Mathworks SIMPOWERSYSTEMS 5 Reference

SimPowerSystems™ 5
Reference
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SimPowerSystems™ Reference
© COPYR IGHT 1998–2010 by Hydro-Québec and The MathWorks, Inc.
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Revision History
January 1998 First printing Version 1.0 (Release 10) September 2000 Second printing Revised for Version 2.1 (Release 12) June 2001 Online only Revised for Version 2.2 (Release 12.1) July 2002 Online only Revised for Version 2.3 (Release 13) (Renamed from Power
System Blockset User’s Guide) February 2003 Third printing Revised for Version 3.0 (Release 13SP1) June 2004 Online only Revised for Version 3.1 (Release 14) October 2004 Fourth printing Revised for Version 4.0 (Release 14SP1) March 2005 Online only Revised for Version 4.0.1 (Release 14SP2) May 2005 Online only Revised for Version 4.1 (Release 14SP2+) September 2005 Online only Revised for Version 4.1.1 (Release 14SP3) March 2006 Online only Revised for Version 4.2 (Release 2006a) September 2006 Online only Revised for Version 4.3 (Release 2006b) March 2007 Online only Revised for Version 4.4 (Release 2007a) September 2007 Online only Revised for Version 4.5 (Release 2007b) March 2008 Online only Revised for Version 4.6 (Release 2008a) October 2008 Online only Revised for Version 5.0 (Release 2008b) March 2009 Online only Revised for Version 5.1 (Release 2009a) September 2009 Online only Revised for Version 5.2 (Release 2009b) March 2010 Online only Revised for Version 5.2.1 (Release 2010a)
Block Reference
1
Electrical Sources ................................. 1-2
Contents
Elements
Power Electronics
Machines
Applications
Electric Drives Flexible AC Transmission Systems (FACTS) Distributed Resources (DR)
Measurements
Extras
Signal Measurem ents Signal and Pulse Sources
Powergui
.......................................... 1-2
................................. 1-5
......................................... 1-5
...................................... 1-7
.................................... 1-7
......................... 1-10
..................................... 1-10
............................................ 1-11
............................. 1-11
........................... 1-11
......................................... 1-13
........... 1-9
v
Blocks — Alphabetical List
2
Function Reference
3
Technical Conventions
A
International System of Units ....................... A-2
B
Per Unit
What Is the Per Unit System? Example 1: Three-Phase Transformer Example 2: Asynchronous Machine Base Values for Instantaneous Voltage and Current
Why Use the Per Unit System Instead of the Standard SI
.......................................... A-3
....................... A-3
................. A-5
................... A-6
Waveforms
Units?
..................................... A-8
........................................ A-8
Bibliography
Index
vi Contents

Block Reference

Electrical Sources (p. 1-2) Generate electric signals
1
Elements (p. 1-2)
Power Electronics (p. 1-5) Machines (p. 1-5) Applications (p. 1-7 ) Access electric drives, F ACTS, and
Measurements (p. 1-10) Current and voltage measurements Extras (p. 1-11) Additional useful blocks, such as
Powergui (p. 1-13) Opens graphical user interface for
Linear and nonlinear circuit elements
Power electronics devices Power machinery models
distributed resources
specialized measurement and control blocks
steady-state analysis of electrical circuits
1 Block Reference

Electrical Sources

Eleme
nts
AC Current Source AC Voltage Source Battery Controlled Current Source Controlled Voltage Source DC Voltage Source Implement DC voltage source Three-Pha
Source
Three-P
Break
Conn
se Programmable Voltage
hase Source
er
ection Port
Implement sinusoidal current source Implement sinusoidal voltage source Implement generic battery model Implement co Implement c
Implement source wit variatio frequenc
Implement three-phase source with internal R-L impedance
ment circuit breaker opening
Imple
rrent zero crossing
at cu
te Physical Modeling connector
Crea
for subsystem
port
ntrolled current source
ontrolled voltage source
three-phase voltage
h programmable time
nofamplitude,phase,
y, and harmonics
1-2
Distributed Parameter Line Implement N-phase distributed
parameter transmission line model
with lumped losses Ground Grounding Transformer
Linear Transformer
Provide connection to ground
Implement three-phase grounding
transformer providing a neutral in
three-wire system
Implement two- or three-winding
linear transformer
Elements
Multi-Winding Transformer
Implement multi-windin g
transformer with taps Mutual Inductance Implement inductances with mutual
coupling Neutral Implement common node in circuit Parallel RLC Branch Implement parallel RLC branch Parallel RLC Load Implement linear parallel RLC load PI Section Line
Implement single-phase
transmission line with lumped
parameters Saturable Transformer
Implement two- or three-winding
saturable transformer Series RLC Branch Implement series RLC branch Series RLC Load Implement linear series R LC load Surge Arrester
Implement metal-oxide surge
arrester Three-Phase Breaker Implement three-phase circuit
breaker opening at current zero
crossing Three-Phase Dynamic Load Im pleme nt three-phase dynamic
load with active power and reactive
power as function of voltage or
controlled from external input Three-Phase Fault Implement programmable
phase-to-phase and phase-to-ground
fault breaker system Three-Phase Harmonic Filter
Implement four types of three-phase
harmonic filters using RLC
components Three-Phase Mutual Inductance
Z1-Z0
Implement three-phase impedance
with mutual coupling among phases Three-Phase Parallel RLC Branch Implement three-phase parallel RLC
branch
1-3
1 Block Reference
Three-Phase Parallel RLC Load Implement three-phase parallel RLC
load with selectable connection Three-Phase PI Section Line
Three-Phase Series RLC Branch Implement three-phase series RLC
Three-Phase Series RLC Load Implement three-phase series RLC
Three-Phase Transformer (Three Windings)
Three-Phase Transformer (Two Windings)
Three-Phase Transformer 12 Terminals
Three-Phase Transformer Inductance M atrix Type (Three Windings)
Three-Phase Transformer Inductance Matrix Type (Two Windings)
Implement three-phase transmission
line section with lumped parameters
branch
load with selectable connection
Implement three-phase transformer
with configurable winding
connections
Implement three-phase transformer
with configurable winding
connections
Implement three single-phase,
two-winding transformers where all
terminals are accessible
Implement three-phase
three-winding transform er with
configurable winding connections
and core geometry
Implement three-phase two-winding
transformer with configurable
winding connections and core
geometry
1-4
Zigzag Phase-Shifting Transformer Implement zigzag phase-shifting
transformer with configurable
secondary winding connection

Power Electronics

Diode Implement diode model GTO Implement gate turn off (GTO)
Power Electronics
thyristor model

Machines

Ideal Switch IGBT
IGBT/Diode Implements
MOSFET Implement Three-Level Bridge Implement three-level neutral point
Thyristor Implement thyristor model
rsal Bridge
Unive
Asynchronous Machine Model the dynamics of three-phase
Implement ide
Implement in
transistor (
MOSFET and
clamped (NPC) power converter
with selectable topologies and power
switching devices
ment universal power
Imple
rter with selectable topologies
conve
ower electronic devices
and p
asynchronous machine, also known
as induction machine
al switch device
sulated gate bipolar
IGBT)
ideal IGBT, GTO, or
antiparallel diode
MOSFET model
DC Machine Implement wound-field or
permanent magnet DC machine Excitation System Provide excitation system for
synchronous machine and regulate
its terminal voltage in generating
mode
1-5
1 Block Reference
Generic Power System Stabilizer
Hydraulic Turbine and Governor
Machine Measurement Demux
Multiband Power System Stabilizer
Permanent Magnet Synchronous Machine
Simplified Synchronous Machine Model the dynamics of simplified
Single Phase Asynchronous Machine Model the dynamics of single
Steam Turbine and Governor Model the dynamics of speed
Implement generic power system
stabilizer for synchronous machine
Model hydraulic turbine and
proportional-integral-derivative
(PID) governor system
Split measurement signal of machine
models into separate signals
Implement multiband power system
stabilizer
Model the dynamics of three-phase
permanent magnet synchronous
machine with sinusoidal or
trapezoidal back electromotive force
(back EMF)
three-phase s ynchronous machine
phase asynchronous machine with
squirrel-cage rotor
governing system, steam turbine,
and multimass shaft
1-6
Stepper Motor Switched Reluctance Motor Model the dynamics of switched
Synchronous Machine Model the dynamics of three-phase
Implement stepper motor mo de l
reluctance motor
round-rotor or s alient-po le
synchronous machine

Applications

Applications
Electric Drives (p. 1-7) AC and D C electric drives models Flexible AC Transmission Systems
(FACTS) (p. 1-9) Distributed R esources (DR) (p. 1-10)
FACTS models
Wind turbine models

Electric Drives

DC Drives (p. 1-7) DC electric drives AC Drives (p. 1-8) AC electric drives Shafts and Speed Reducers (p. 1-8) Shafts and speed reducers Extra Sources (p. 1-9)
DC Drives
Four-Qu
Four-Q Rectif
Four-Quadrant Three-Phase Rectifier DC Drive
adrant Chopper DC Drive
uadrant Single-Phase
ier DC Drive
Extra electrical sources
Impleme
DC drive
Implement single-phase
dual-converter DC drive with
circulating current
Implement three-phase
dual-converter DC drive with
circulating current
nt four-quadrant chopper
One-Quadrant Chopper DC D rive
o-Quadrant Chopper DC Drive
Tw
lement one-quadrant chopper
Imp
ck converter topology) DC drive
(bu
Implement two-qua dra n t chopper
(buck-boost converter topology) DC
drive
1-7
1 Block Reference
Two-Quadrant Single-Phase Rectifier DC Drive
Two-Quadrant Three-Phase Rectifier DC Drive
Implement two-quadrant
single-phase rectifier DC drive
Implement two-quadrant
three-phase rectifier DC drive
AC Drives
Brushless DC Motor Drive Implement brushless DC motor
drive using Permanent Magnet
Synchronous Motor (PMSM) with
trapezoidal back electromotive force
(BEMF) DTC Induction M otor Drive Implement direct torque and flux
control (DTC) induction motor drive
model Field-Oriented Control Induction
Motor Drive PM Synchronous Motor Drive
Self-Controlled Synchronous Motor Drive
Implement field-oriented control
(FOC) induction motor drive model
Implement P ermanent Magnet
Synchronous Motor (PMSM) vector
control drive
Implement Self-Controlled
Synchronous Motor Drive
1-8
Six-Step VSI Induction Motor Drive Implement six -ste p inverter fed
Induction Motor Drive Space Vector PWM VSI Induction
Motor Drive
Implement space vector PWM VSI
induction motor drive
Shafts and Speed Reducers
Mechanical Shaft Implement mechanical shaft Speed Reducer
Implement speed reducer
Extra Sources
Applications
Battery Fuel Cell Stack Implement generic hydrogen fuel
Implement generic battery model
cell stack model

Flexible AC Transmission Systems (FACTS)

Power-Electronics Based FACTS (p. 1-9)
Transformers (p. 1-10) Transformer models
Power-Electronics Based FACTS
Static Synchronous Compensator (Phasor Type)
Static Synchronous Series Compensator (Phasor Type)
Static Var Compensator (Phasor Type)
Power-electronics based models
Implement phasor model of
three-phase sta tic synchronous
compensator
Implement phasor model of
three-phase sta tic synchronous
series compensator
Implement phasor model of
three-phase static var compensator Unified Power Flow Controller
(Phasor Type)
Implement phasor model of
three-phase unified power flow
controller
1-9
1 Block Reference
Transformers
Three-Phase OLTC Phase Shifting Transformer Delta-Hexagonal (Phasor Type)
Three-Phase O LTC Regulating Transformer (Phasor Type)

Distributed Resources (DR)

Wind Turbine
Wind Turbine Doubly-Fed Induction Generator (Phasor Type)
Wind Turbine Induction Generator (Phasor Type)
Implement phasor model of
three-phase OLTC phase-shifting
transformer using delta hexagonal
connection
Implement phasor model of
three-phase OLTC regulating
transformer
Implement model of variable pitch
wind turbine
Implement phasor model of variable
speed doubly-fed induction generator
driven by wind turbine
Implement phasor model of
squirrel-cage induction generator
driven by variable pitch wind turbine

Measurements

1-10
Current Measurement Impedance Measurement
Multimeter Measure v oltages and currents
Three-Phase V-I Measurement Measure three-phase currents and
Voltage Measurement Measure voltage in circuit
Measure current in circuit
Measure impedance of circuit as
function of frequency
specified in d i al og boxes of
SimPowerSystems™ blocks
voltages in circuit

Extras

Extras
Signal Measurements (p. 1-11) Specialized measurement blocks Signal and Pulse Sources (p. 1-11) Specialized source blocks

Signal Measurements

abc_to_dq0 Transformation Perform Park transformation from
three-phase (abc) reference frame to
dq0 reference frame Active & Reactive Power
dq0_to_abc Transformation Perform Park transformation from
Fourier RMS Measure root mean square (RMS)
Three-Phase Sequence Analyzer
Total Harmonic Distortion Measure total harmonic distortion
Measure active and reactive powers
of voltage-current pair
dq0 reference frame to abc reference
frame
Perform Fourier analysis of signal
value of signal
Measur
and zer
three
(THD)ofsignal
e positive-, negative-, o-sequence components of
-phase signal

Signal and Pulse Sources

PWM Generator Generate pulses for carrier-based
two-level pulse width modulator
(PWM) in converter bridge Synchronized 12-Pulse Generator
Implement synchronized pulse
generator to fire thyristors of
twelve-pulse converter
1-11
1 Block Reference
Synchronized 6-Pulse G enerator
Timer
Implement synchronized pulse
generator to fire thyristors of
six-pulse converter
Generate signal changing at
specified transition tim es
1-12

Powergui

Powergui
Powergui
Environment block for
SimPowerSystems models
1-13
1 Block Reference
1-14
2

Blocks — Alphabetical List

abc_to_dq0 Transformation
Purpose Perform Park transformation from three-phase (abc) reference frame to
dq0 reference frame
Library Extras/Measurements
A discrete version of this block is available in the Extras/Discrete Measurements library.
Description The abc_to_dq0 Transformation block computes the direct axis,
quadratic axis, and zero sequence quantities in a two-axis rotating reference frame for a three-phase sinusoidal signal. The following transformation is used:
2-2
where ω = rotation speed (rad/s) of the rotating frame. The transformation is the same for the case of a three-phase current;
you simply replace the V I
c,Id,Iq
,andI0variables.
a,Vb,Vc,Vd,Vq
,andV0variables with the Ia,Ib,
This transformation is commonly used in three-phase electric machine models, where it is known as a Park tran sf orm a tion [1]. It allows you to eliminate time-varying indu c tances by referring the stator and rotor quantities to a fixed or rotating reference frame. In the case of a synchronous machine, the stator quantities are referred to the ro tor. I
and Iqrepresent the two DC currents flowing in the two equivalent
d
rotor windings (d winding directly on thesameaxisasthefieldwinding, and q winding on the quadratic axis), producing the same flux as the stator I
,andIccurrents.
a,Ib
You can use this block in a control system to measure the positive-sequence component V
of a set of three-phase voltages or
1
abc_to_dq0 Transformation
currents. The Vdand Vq(or Idand Iq) then represent the rectangular coordinates of the positive-sequence component.
You can use the Math Function block and the Trigonometric Function block to obtain the modulus and angle of V
:
1
Dialog Box and Parameter
Inputs and Outputs
This measure Fourier anal harmonics a
ment system does not introduce any delay, but, unlike the
ysis done in the Sequence Analyzer block, it is sensitive to
nd imbalances.
s
abc
Connect to the first input the vectorized sinusoidal phase signal to be converted [phase A phase B phase C].
sin_cos
Connect to the second input a vectorized signal containing the [sin(ωt) cos(ωt)] values, where ω is the rotation speed of the reference frame.
dq0
The output is a vectorized signal containing the three sequence components [d q o].
2-3
abc_to_dq0 Transformation
Example The power_3phsignaldq demo uses a Discrete Three-Phase
Programmable Source block to generate a 1 pu, 15 degrees positive sequence voltage. At 0.05 second the positive sequence voltage is increased to 1.5 pu and at 0.1 second an imbalance is introduced by the addition of a 0.3 pu negative sequence component with a phase of -30 degrees. The magnitude and phase of the positive-sequence component areevaluatedintwodifferentways:
Sequence calculation of phasors using Fourier analysis
abc-to-dq0 transformation
2-4
Start the simulation and observe the instantaneous signals Vabc (Scope1), the signals returned by the Sequence Analyzer (Scope2), and the abc-to-dq0 transformation (Scope3).
abc_to_dq0 Transformation
2-5
abc_to_dq0 Transformation
2-6
Note tha immune t is a one­Howeve
r, an imbalance produces a ripple at the V1 and Phi1 outputs.
t the Sequence Analyzer, which uses Fourier analysis, is
o harmonics and imbalance. However, its response to a step
cycleramp.Theabc-to-dqotransformation is instantaneous.
abc_to_dq0 Transformation
References [1] Krause, P. C. Analysis of Electric Machinery.NewYork:
McGraw-Hill, 1994, p.135.
See Also dq0_to_abc Transforma tion
2-7
AC Current Source
Purpose Implement sinusoidal current source
Library Electrical Sources
Description The AC Current Source block implements an ideal AC current source.
The positive current direction is indicated by the arrow in the block icon. The generated current I is described by the following relationship:
Negative values are allowed for amplitude and phase. A zero frequency and a 90 degree phase specify a DC current source. You cannot enter a negative frequency; the software returns an error in that case, and the block displays a question mark in the block icon. You can modify the first three block parameters at any time during the simulation.
Dialog Box and Parameters
2-8
Peak a
The p
mplitude
eak amplitude of the generated current, in amperes (A).
AC Current Source
Phase
The phase in degrees (deg). Specify a frequency of 0 and a p hase of 90 degrees to implement a DC current source.
Frequency
The source frequency in hertz (Hz). Specify a frequency of 0 and a phase of 90 degrees to implement a DC current source.
Sample time
The sample period in seconds (s). The default is to a continuous source.
Measurements
Select Current Source block.
Place a Multimeter block in your m ode l to display the selected measurements during the simulation. In the Available Measurements list box of the Multimeter block, the measurement is identified by a label followed by the block name.
Current to measure the current flowing through the AC
0, corresponding
Measurement Label
Current
Isrc:
Example The power_accurrent demo uses two AC Current Source blocks in
parallel to sum two sinusoidal currents in a resistor.
2-9
AC Current Source
See Also Controlled Current Source, M ultimeter
2-10
Active & Reactive Power
Purpose Measure active and reactive pow ers of voltage-current pair
Library Extras/Measurements
A discrete version of this block is available in the Extras/Discrete Measurements library.
Description The Active & Reactive Power block measures the active power P and
reactive power Q associated with a periodic voltage-current pair that can contain harmonics. P and Q are calculated by averaging the V I product with a running average window over one cycle of the fundamental frequency, s o that the powers are evaluated at fundamental frequency.
where T = 1/(fundamental frequency). A current flowing into an RL branch, for example, produces positive
active and reactive powers. As this block uses a running window, one cycle of simulation has to be
completed before the output gives the correct active and reactive powers. The discrete version of this block, a vailable in the Extras/Discrete
Measurements library, allows you to specify the initial input voltage and current (magnitude and phase). For the first cycle of simulation the outputs are held constant using the values specified by the initial input parameters.
2-11
Active & Reactive Power
Dialog Box and Parameters
Fundamental freq uency (Hz)
The fundamental frequency, in hertz, of the instantaneous voltage and current.
Inputs and Outputs
V
The first input is the instantaneous voltage.
I
The secon
PQ
The outp
d input is the instantaneous current.
ut is a vector [P Q] of the active and reactive powers.
Example The power_transfo demo simulates a three-winding distribution
transformer rated at 75 kVA:14400/120/120 V. The transformer primary winding is connected to a high-voltage source of 14400 Vrms. Two identical inductive loads (20 kW-10 kvar) are connected to the two secondary windings. A third capacitive load (30 kW-20 kvar) is fed at 240 V.
2-12
Active & Reactive Power
Initially, the circuit breaker in series with Load 2 is closed, so that the system is balanced. When the circuit breaker opens, a current starts to flow in the neutral path as a result of the load imbalance.
The active power computed from the primary voltage and current is measured by an Active & Reactive Power block. When the breaker opens, the active power decreases from 70 kW to 50 kW.
2-13
Active & Reactive Power
2-14
AC Voltage Source
Purpose Implement sinusoidal voltage source
Library Electrical Sources
Description The AC Voltage Source block implements an ideal AC voltage source.
The generated voltage U is described by the following relationship:
Negative values are allowed for amplitude and phase. A frequency of 0 and phase equal to 90 degrees specify a DC voltag e source. Negative frequency is not allowed; otherwise the software signals an error, and the block displays a question mark in the block icon.
Dialog Box and Parameters
Peak amplitude
The peak amplitude o f the generated voltage, in volts (V).
Phase
The phase in degrees (deg).
Frequency
The source frequency in hertz (Hz).
2-15
AC Voltage Source
Sample time
The sample period in seconds (s). The default is to a continuous source.
Measurements
Select the AC Voltage Source block.
Place a Multimeter block in your m ode l to display the selected measurements during the simulation. In the Available Measurements list box of the Multimeter block, the measurement is identified by a label followed by the block name.
Voltage tomeasurethevoltageacrosstheterminalsof
Measurement Label
Voltage
Usrc:
Example The power_acvoltage demo uses two AC Voltage Source blocks at
different frequencies connected in series across a resistor. The sum of the two voltages is read by a Voltage Measurement block.
0, corresponding
See Also Controlled Voltage Source, DC Voltage Source, Multimeter
2-16
Asynchronous Machine
Purpose Model the dynamics of three-phase asynchronous machine, also known
as induction machine
Library Machines
Description The Asynchronous Machine block operates in either generator or motor
mode. The mode of operation is dictated by the sign of the mechanical torque:
If Tm is positive, the machine acts as a motor.
If Tm is negative, the machine acts as a generator.
The electrical part of the machine is represented by a fourth-order state-space model and the mechanical part by a second-order system. All electrical variables and parameters are referred to the stator. This is indicated by the prime signs in the machine equations given below. All stator and rotor quantities are in the arbitrary two-axis reference frame (dq frame). The subs cripts used are defined as follows:
Subscript Definition
d d axis quantity q r s
l Leakage inductance m
qaxisquantity Rotor quantity Stator quantity
Magnetizing inductance
2-17
Asynchronous Machine
Electrical System
2-18
Mechanical System
The Asynchronous Machine block parameters are defined as follows (all quantities are referred to the stator):
Parameter Definition
Rs,L R’r,L’ L
m
Ls,L’
ls
lr
r
Stator resistance and leakage inductance Rotor resistance and leakage inductance Magnetizing inductance Total stator and rotor inductances
Parameter Definition
Asynchronous Machine
Vqs,i V’qr,i’ Vds,i V’dr,i’
ϕqs, ϕ ϕqr, ϕ’
ω
m
Θ
m
p
ω
r
Θ
r
T
e
T
m
J
H
F
qs
qr
ds
dr
ds
dr
q axis stator voltage and current q axis rotor voltage and current d axis stator voltage and current d axis rotor voltage and current Stator q and d axis fluxes Rotorqanddaxisfluxes Angular velocity of the rotor Rotor angular position Number of pole pairs Electrical angular velocity (ωmxp) Electrical rotor angular position (Θmxp) Electromagnetic torque Shaft mechanical torque Combined rotor and load inertia coefficient. Set
to infinite to simulate locked rotor. Combined rotor and load inertia constant. Set to
infinite to simulate locked rotor. Combined rotor and load viscous friction
coefficient
Dialog Box and Parameters
You can choose between two Asynchronous M achine blocks to specify the electrical and mechanical parameters of the model, by using the pu Units dialog box or the SI dialog box. Both blocks are modeling the same asynchronous machine model. Depending on the dialog box y ou choose to use, SimPowerSystems software automatically converts the parameters you enter into per unit parameters. The Simulink
®
model of
the Asynchronous Machine block uses pu parameters.
2-19
Asynchronous Machine
Configuration Tab
2-20
Preset model
Provides a set of predetermined electrical and mechanical parameters for various asynchronous machine ratings of power (HP), phase-to-phase voltage (V), frequency (Hz), and rated speed (rpm).
Select one of the preset models to load the corresponding electrical and mechanical parameters in the entries of the dialog box. Note that the preset models do not include predetermined saturation parameters. Select preset model, or if you want to modify some of the parameters of a preset model, as des cribed below.
No if you do not want to use a
Asynchronous Machine
When you select a preset model, the e lectrical and mechanical parameters in the Parameters tab of the dialog box become unmodifiable (grayed out). To start from a given preset model and thenmodifymachineparameters,youhavetodothefollowing:
1 Select the desired preset model to initialize the parameters. 2 Change the Preset model parameter value to No.Thiswillnot
change the machine parameters. By doing so, you just break the connection w ith the particular preset model.
3 Modify the machine parameters as you wish, then click Apply.
Mechanical input
Allows you to select either the torque applied to the shaft or the rotor speed as the Simulink signal applied to the block’s input.
Select Torque Tm to specify a torque input, in N.m or in pu, and change labeling of the block’s input to determined by the machine InertiaJ(orinertiaconstantHforthe pu machine) and by the difference between the applied mechanical torque Tm and the internal electromagnetic torque Te. The sign convention for the mechanical torque is the following: when the speed is positive, a positiv e torque signal indicates motor mode and a negative signal indicates generator mode.
Tm. The machine speed is
Select Speed w to specify a speed input, in rad/s or in pu, and change labeling of the block’s input to is imposed and the mechanical part of the model (Inertia J) is ignored. Using the spee d as the mechanical input allows modeling a mechanical coupling between two machines and interfacing with SimMechanics™ and SimDriveline™ models.
The next figure indicates how to model a stiff shaft interconnection in a motor-generator set when friction torque is ignored in machine 2. The speed output of machine 1 (motor) is connected to the speed input of machine 2 (generator), while machine 2 electromagnetic torque output Te is applied to the mechanical torque input Tm of machine 1. The Kw factor takes into account
w. The machine speed
2-21
Asynchronous Machine
speed units of both machines (pu or rad/s) and gear box ratio w2/w1. The KT factor takes into account torque units of both machines (pu or N.m) and machine ratings. Also, as the inertia J2 is ignored in machine 2, J2 referred to m achine 1 speed must be added to machine 1 inertia J1.
Rotor type
Specifies the branching for the rotor windings.
2-22
Reference frame
Specifies the reference frame that is used to convert input voltag es (abc reference frame) to the dq reference frame, and output currents (dq reference frame) to the abc reference frame. You can choose among the following reference frame transformations:
Rotor (Park transformation) Stationary (Clarke or αβ transformation)
Synchronous
The following relationships describe the abc-to-dq reference frame transformations applied to the Asynchronous Machine phase-to-phase voltages.
Asynchronous Machine
In the preced reference frame, while
position of the reference frame and the position (electrical) of the rotor. Because the machine windings are connected in a three-wire Y configuration, there is no homopolar (0) component. This also justifies the fact that two line-to-line input voltages are used inside the model instead o f three line-to-neutral voltages. The following relationships describe the dq-to-abc reference frame transformations applied to the Asynchronous Machine phase currents.
The following table shows the values taken by Θ and β in ea ch reference frame (Θ reference frame).
ing equations, Θ is the angular position of the
is the difference between the
is the position of the synchronously rotating
e
2-23
Asynchronous Machine
Reference Frame
Rotor Stationary Synchronous Θ
The choice of reference frame affects the waveforms of all dq variables. It also affects the simulation speed and in certain cases the accuracy of the results. The following guidelines are suggested in [1]:
Use the stationary reference frame if the stator voltages are either unbalanced or discontinuous and the rotor voltages are balanced (or 0).
Use the rotor reference frame if the rotor voltages are either unbalanced or discontinuous and the stator voltages are balanced.
Use either the stationary or synchronous reference frames if all voltages are balanced and continuous.
Θ
r
0
e
0
-Θ
r
Θe- Θ
r
2-24
Mask units
Specifies the units of the electrical and mechanical parameters of the model. This parameter is not modifiable; it is pr ovided for information purposes only.
Parameters Tab
Asynchronous Machine
Nominal power, voltage (line-line), and frequency
The nominal apparent power Pn (VA), RMS line-to-line voltage Vn (V), and frequency fn (Hz).
Stator resistance and inductance
The stator resistance Rs (Ω or pu) and leakage inductance Lls (H or pu).
Rotor resistance and inductance
The rotor resistance Rr’ (Ω or pu) and leakage inductance Llr’ (H or pu), both referred to the stator.
Mutual inductance
The magnetizing inductance Lm (H or pu).
2-25
Asynchronous Machine
Inertia constant, friction factor, and pole pairs
For the SI units dialog box: the combined machine and load inertia coefficient J (kg.m (N.m.s), and pole pairs p. The friction torque Tf is proportional to the rotor speed ω (T f = F.w).
For the pu units dialog box: the inertia constant H (s), combined viscous friction coefficient F (pu), and pole pairs p.
Initial conditions
Specifies the initial slip s, electrical angle Θe (degrees), stator current magnitude (A or pu), and phase angles (degrees):
2
), combined viscous friction coefficient F
[slip, th, i
as,ibs,ics
,phaseas,phasebs,phasecs]
For the wound-rotor machine, you can also specify optional initial values for the rotor current magnitude (A or pu), and phase angles (degrees):
[slip, th, ias,ibs,ics, phaseas, phasebs, phasecs,iar,ibr,icr,
, phasebr, phasecr]
phase
ar
For the squirrel cage machine, the initial conditions can be computed by the load flow utility in the Powergui block.
Simulate saturation
Specifies whether magnetic saturation of rotor and stator iron is simulated or not.
Saturation parameters
Specifies the no-load s aturation curve parameters. Magnetic saturation of stator and rotor iron (saturation of the mutual flux) is modeled by a nonlinear function (in this case a polynomial) using points of the no-load saturation curve. You must enter a 2-by-n matrix, where n is the number of points taken from the saturation curve. The first row of this matrix contains the values of stator currents, while t he second row contains values of corresponding terminal voltages (stator voltages). The first point
2-26
Asynchronous Machine
(first column of the matrix) must correspond to the point where the effect of saturation begins.
You must select the Simulate saturation check box to simulate saturation. If the Simulate saturation is not selected, the relationship between the stator current and the stator voltage is linear.
Advanced Tab
le time (-1 for inherited)
Samp
ifies the sample time used by the block. To inherit the sample
Spec
specified in the Powergui block, set this parameter to
time
-1.
2-27
Asynchronous Machine
Inputs and Outputs
Tm
The Simulink input of the block is the m echanical torque at the machine’s shaft. When the input is a positive Simulink signal, the asynchronous machine behaves as a motor. When the input is a negative signal, the asynchronous machine behaves as a generator.
When you use the SI parameters mask, the input is a signal in N.m, otherwise it is in pu.
w
The alternative block input (depending on the value of the Mechanical input parameter) is the machine speed, in rad/s.
m
The Simulink output of the block is a vector containing 21 signals. You can demultiplex these signals by u sing the Bus Selector block provided in the Simulink library. Depending on the type of mask you use, the units are in SI, or in pu.
Signal Definition Units Symbol
1 2 3 4 5 6 7 8 9 10 11
Rotor current ir_a Rotor current ir_b Rotor current ir_c Rotor current iq Rotor current id Rotor flux phir_q Rotor flux phir_d Rotor voltage Vr_q Rotor voltage Vr_d
Aorpu i’ Aorpu i’ Aorpu i’ Aorpu i’ Aorpu i’ V.s or pu V.s or pu Vorpu
Vorpu Stator current is_a A or pu Stator current is_b A or pu
ϕ ϕ
v’ v’ i i
ra
rb
rc
qr
dr
qr
dr
qr
d
sa
sb
2-28
Asynchronous Machine
Signal Definition Units Symbol
12 13 14 15 16 17 18 19 20 21
Stator current is_c A or pu Stator current is_q A or pu Stator current is_d A or pu Stator flux phis_q Stator flux phis_d Stator voltage vs_q Stator voltage vs_d
V.s or pu V.s or pu Vorpu
Vorpu Rotor speed rad/s Electromagnetic torque Te
N.m or pu T Rotor angle thetam rad
The s tator terminals of the Asynchronous Machine block are identified by the A, B, and C letters. The rotor terminals are identified by the a, b, and c letters. Note that the neutral connections of the stator and rotor windings are not available; three-wire Y connections are assumed.
i
sc
i
qs
i
ds
ϕ
qs
ϕ
ds
v
qs
v
ds
ω
m
e
Θ
m
Limitations 1 The Asynchronous Machine block does not include a representation
of the saturation of leakage fluxes. You must be careful when you connect ideal sources to the machine’s stator. If you choose to supply the stator via a three-phase Y-connected infinite voltage source, you must use three sources connected in Y. However, if you choose to simulate a delta source connection, you must use only tw o sources connected in series.
2-29
Asynchronous Machine
2 When you use Asynchronous Machine blocks in discrete systems, you
might have to use a small parasitic resistive load, connected at the machine terminals, in order to avoid numerical oscillations. Large sample times require larger loads. The minimum resistive load is proportional to the sample time. As a rule of thumb, remember that with a 25 μs time step on a 60 Hz system, the minimum load is approximately 2.5% of the machine nominal power. For example, a 200 MVA asynchronous machine in a power system discretized with a50μssampletimerequiresapproximately 5% of resistive load or 10 MW. If the sample time is reduced to 20 μs, a resistive load of 4 MW should be sufficient.
Examples Example 1: Use of the Asynchronous Machine Block in
Motor Mode
The power_ pwm demo illustrates the use of the Asynchronous Machine block in motor mode. It consists of an asynchronous machine in an open-loop speed control system.
The machine’s rotor is short-circuited, and the stator is fed by a PW M inverter, built with Simulink blocks and interfaced to the Asynchronous Machine block through the Controlled Voltag e Source block. The inverter uses sinusoidal pulse-width modulation, which is described in [2].Thebasefrequencyofthesinusoidal reference wave is set at 60 Hz and the triangular carrier wave’s frequency is set at 1980 Hz. This
2-30
corresponds to a frequency modulation factor m
1980). It is recommended in [2] that m that the value be as high as possible.
be an odd multiple of three and
f
of 33 (60 Hz x 33 =
f
Asynchronous Machine
The3HPmachineisconnectedtoaconstant load of nominal value (11.9 N.m). It is started and reaches the set point speed of 1.0 pu at t = 0.9 second.
The parameters of the machine are thos e found in the SI Units dialog box above, except for the stator leakage inductance, which is set to twice its normal value. This is done to simulate a smoothing inductor placed between the inverter and the machine. Also, the stationary reference frame was used to obtain the results shown.
Open the p ower _pwm demo. Note in the simulation parameters that a small relative tolerance is required because of the high switching rate of the inverter.
Run the simulation and observe the machine’s speed and torque.
2-31
Asynchronous Machine
2-32
The first graph shows the machine’s speed going from 0 to 1725 rpm (1.0 pu). The second graph shows the electromag netic torque developed by the machine. Because the stator is fed by a PWM inverter, a noisy torque is observed.
However, this noise is not visible in the spe e d because it is filtered out by the m achine’s inertia, but it can also be seen in the stator and rotor currents, which are observed next.
Asynchronous Machine
Finally, look at the output of the PWM inverter. Because nothing of interest can be seen at the simulation tim e scale, the graph concentrates on the last moments of the simulation.
2-33
Asynchronous Machine
2-34
Example 2: Effect of Saturation of the Asynchronous Machine Block
The power_asm_sat demo illustrates the effect of saturation of the Asynchronous Machine block.
Two identical three-phase motors (50 HP, 460 V, 1800 rpm) are simulated with and without saturation, to observe the saturation effects on the stator currents. Tw o different simulations are realized in the demo.
Asynchronous Machine
The first simulation, is the no-load steady-state test. The table below contains the values of th e Saturation Parameters and the measurements obtained by simulating different operating points on the saturated motor (no-load and in steady-state).
Saturation Parameters Measurements
Vsat (Vrms L-L) Isat (peak A) Vrms L-L Is_A (peak A)
-­230 14.04 230 14.03
--
-­322 27.
--
81
120 7.322
250 16.86 300 24.04 322 28. 351 35.22
39
2-35
Asynchronous Machine
Saturation Parameters Measurements
Vsat (Vrms L-L) Isat (peak A) Vrms L-L Is_A (peak A)
-­414
--
-­460 72.69 460 73.01
--
-­506 97.98 506 100.9
--
--
-­552 148.68 552 146.3
--
-­598 215.74 598 216.5
--
-­644 302.98 644 313.2
--
--
-­690 428.78 690 432.9
53.79
382 43.83 414 426 58.58 449 67.94
472 79.12 488 88.43
519 111.6 535 126.9 546 139.1
569 169.1 581 187.4
620 259.6 633 287.8
659 350 672 383.7 681 407.9
54.21
2-36
Asynchronous Machine
The graph below illustrates these results and shows the accuracy of the saturation model. As you can se e, the measured operating points fit well the curve that is plotted from the Saturation Parameters data.
Running the simulation with a blocked rotor or with many different values of load torque will allow t he observation of other effects of saturation on the stator currents.
References [1] Krause, P.C., O. Wasynczuk, and S.D. Sudhoff, Analysis of Electric
Machinery, IEEE Press, 2002.
2-37
Asynchronous Machine
[2] Mohan, N., T.M. Undeland, and W.P. Robbins, Power Electronics: Converters, Applications, and Design, J ohn Wiley & Sons, Inc., New
York, 1995, Section 8.4.1.
See Also Powergui
2-38
Battery
Purpose Implement generic battery model
Library Electrical Sources, E lectric Drives/Extra Sources
Description The B attery block implements a generic dynamic model parameterized
to represent most popular types of rechargeable batteries. The equivalent circuit of the battery is shown below:
Lead-Acid Model
Discharge model (i* > 0)
Charge Model (i* < 0)
2-39
Battery
Lithium-Ion Model
Discharge Model (i* > 0)
Charge Model (i* < 0)
Nickel-Cadmium and Nickel-Metal-Hydride Model
Discharge Model (i* > 0)
Charge Model (i*< 0)
where,
2-40
= Nonlinear voltage (V)
E
Batt
=Constantvoltage(V)
E
0
Exp(s) = Exponential zone dynamics (V) Sel(s) = Represents the battery mode. Sel(s) = 0 during battery
discharge, Sel(s) = 1 during battery charging.
-1
K = P olarization constant (Ah
) or Polarization resistance (Ohms) i* = Low frequency current dynamics (A) i = Battery current (A) it = Extracted capacity (Ah) Q = Maximum battery capacity (A h) A = Exponential voltage (V) B = Exponential capacity (Ah)
-1
Battery
The parameters of the equivalent circuit can be modified to represent a particular battery type, based on its discharge characteristics. A typical discharge curve is composed of three sections, as shown in the next figure:
The first section represents the exponential voltage drop when the battery is charged. Depending on the battery type, this area is more or less wide. The second section represents the charge that can be extracted from the battery until the voltage drops below the battery nominal voltage. Finally, the third section represents the total discharge of the battery, when the voltage drops rapidly.
When the battery current is negative, the battery will recharge following a charge characteristic as shown below:
2-41
Battery
2-42
Note that the parameters of the model are deduced from discharge characteristics and assumed to be the same for charging.
The E xp(s) transfer function represents the hysteresis phenomenon for the Lead-Acid, NiCD and NiM H batteries during charge and discharge cycles. The exponential voltage increases when battery is charging, no matter the SOC of the battery. When the battery is discharging, the exponential voltage decreases immediately:
Battery
2-43
Battery
Dialog Box and Parameters
Parameters Tab
2-44
Battery type
Provides a set of predetermined charge behavior for four types of battery:
Lead-Acid
Lithium-Ion
Nickel-Cadmium
Nickel-Metal-Hydride
Nominal Voltage (V)
The nominal voltage (Vnom) of the battery (volts). The nominal voltage represents the end of the linear zone of the discharge characteristics.
Rated Capacity (Ah)
The rated capacity (Qrated) of the battery in ampere-hour. The rated capacity is the minimum effective capacity of the battery.
Initial State-Of-Charge (%)
The initial State-Of-Charge (SOC) of the battery. 100% indicates a fully charged battery and 0% indicates an empty battery. This parameter is used as an initial condition for the simulation and does not affect the discharge curve (when the option Plot Discharge Characteristics is used).
Battery
Use parameters based on Battery type and nominal values
Load the corresponding parameters in the entries of the dialog box, depending on the selected Battery type,theNominal Voltage and the Rated Capacity.
When a preset model is used, the detailed parameters cannot be modified. If you want to modify th e discharge curve, select the desired battery type to load the default parameters, and then uncheck the Use parameters based on Battery type and
nominal values checkbox to access the detailed parameters.
Maximum Capacity (Ah)
The maximum theoretical capacity (Q), when a d isco ntin uity occurs in the battery voltage. This value i s generally equal to 105% of the rated capacity.
Fully charged Voltage (V)
The fully charged voltage (Vfull), for a given discharge current. Note that the fully charged voltage is not the no-load voltage.
2-45
Battery
Nominal Discharge Current (A)
The nominal discharge current, for which the discharge curve has been measured. For example, a typical discharge current for a 1.5 Ah N iMH battery is 20% of the rated capacity: (0.2 *
1.5 Ah / 1h = 0.3A).
Internal Resistance
The internal resistance of the battery (ohms). When a preset model is used, a generic value is loaded, corresponding to 1% of the nominal power (nominal voltage * rated capacity of the battery). The resistance is supposed to be constant during the charge and the discharge cycles and does not v ary with the amplitude of the current.
Capacity (Ah) @ Nominal Voltage
The capacity (Qnom) extracted from the battery until the voltage drops under the nominal voltage. This value should be between Qexp and Qmax.
Exponential zone [Voltage (V), Capacity (Ah)]
The voltage (Vexp)andthecapacity(Qexp) corresponding to the end of the exponential zone. The voltage s ho uld be between Vnom and Vfull. The capacity should be between 0 and Qnom.
2-46
View Discharge Characteristics Tab
Plot Discharge Characteristics
If selected, plots a figure c on tain in g two grap h s . The first graph represents the nominal discharge curve (at the Nominal Discharge Current) and the second graph represents the discharge curves at the specified discharge currents. When the checkbox is active, the graph remains on and updates itself when a parameter changes in the dialog box. To clear the figure, uncheck and close the figure.
Discharge current
Allows to specify different values of discharge current. The discharge characteristics for these currents are presented in the second part of the graph.
Units
Choose either
Time or A mpere-hour as the x-axis for the plot.
Battery Dynamics Tab
Battery
Battery response time (s)
The response time of the battery (at 95% of the final value).
This value represents the voltage dynamics and can be observed when a current step is applied:
2-47
Battery
In this example, a battery response time of 30 secs is used.
2-48
Battery
Extract Battery Parameters From Data Sheets
This section gives an example of detailed parameters e xtracted from the Panasonic NiMH-HHR650D battery data sheet:
From the specification tables, we obtain the rated capacity and the internal resistance. The other detailed parameters are deduced from the Typical Discharge Characteristics plot:
Param
Rated capacity Internal Resistance Nominal Voltage Rated Capacity 6.5 Ah
eter
Value
h
6.5 A 2mΩ
(a)
1.18 V
2-49
Battery
Parameter Value
Maximum Capacity Fully Charged voltage Nominal Discharge Current Capacity @ Nominal Voltage Exponential Voltage Exponential C apacity
(b)
7 Ah (5.38h * 1.3A)
(c)
(d)
(a)
(e)
(e)
1.39 V
1.3 A
6.25 Ah
1.28 V
1.3 Ah
These parameters are approximate and depend on the precision of the points obtained from the d is charg e curve. A tool, called ScanIt (provided by amsterCHEM, http://www.amsterchem.com) can be used to extract values from data sheet curves.
The parameters obtained from the data sheet are entered in the mask of the Battery block as in the following picture:
2-50
Battery
The discharge curves (the dotted line curves in the following plots) obtained with these parameters are similar to the data sheet curves.
2-51
Battery
2-52
Battery
Cells in Series and/or in Parallel
To model a series and/or parallel combination of c ells based o n the parameters of a single cell, the parameter transformation shown in the next figure can be used. The corresponds to the number of cells in series, and to the number of cell in parallel:
Nb_ser variable in mask below
Nb_par corresponds
2-53
Battery
Block Inputs and Outputs
Model Validation
Model Assumptions
m
The Simulink output of the block is a vector containing three signals. You can demultiplex these signals by using the Bus Selector block provided in the Simulink library.
Signal Definition Units
SOC The State-Of-Charge o f the battery
(between 0 and 100%). The SOC for a fully charged battery is 100% and for an empty battery is 0%. The SOC is calculated as:
Current Voltage The Battery voltage
Experimental validation of the model shown a m aximum error of 5% (when SOC is between 10% and 100%) for charge (current between 0 and 2C) and discharge (current between 0 and 5C) dynamics.
The internal resistance is supposed constant during the charge and
the discharge cycles and doesn’t vary with the amplitude of the current.
The Battery current
%
A V
2-54
The parameters of the model are deduced from discharge
characteristics and assumed to be the same for charging.
The capacity of the battery doesn’t change with the amplitude of
current (No Peukert effect).
The model doesn’t take the temperature into account.
The Self-Discharge of the battery is not represented. It can be
represented by adding a large resistance in parallel with the battery terminals.
Battery
The battery has no memory effect.
Limitations The minimum no-load battery voltage is 0 volt and the maximum
battery voltage is equal to 2*E0.
The minimum capacity of the battery is 0 Ah and the maximum capacity is Qmax.
Example The power_bat tery demo illustrates a 200 volts, 6.5 Ah NiMH battery
connected to a constant load of 50 A. The DC machine is connected in parallel with the load and operates at no load torque. When the State-Of-Charge (SOC) of the battery goes under 0.4 (40%), a negative load torque of 200 Nm is applied to the machine so it acts as a generator to recharge the battery. When the SOC goes over 80%, the load torque is removed so only the battery supplies the 50 amps load .
The simulation produces the followings results:
2-55
Battery
The battery is discharged by the constant DC load of 50 A. When the SOC drops under 0.4, a mechanical torque of -200 Nm is applied so the machine acts as a generator and provides a current of 100 amps. Hence, 50 amps goes to the load and 50 amps goes to recharge the battery. When the SOC g oes over 0.8, the mechanical torque is removed and the machine operates freely. And then the cycle restarts.
References [1]C.M.Shepherd,"DesignofPrimary and Secondary Cells - Part 2.
An equation describing battery discharge," Journal of Electrochemical Society, Volume 112, Jul. 1965, pp. 657-664
[2] Tremblay, O.; Dessaint, L.-A.; Dekkiche,A.-I.,"AGenericBattery Model for the Dynamic Simulation of Hybrid Electric Vehicles," Vehicle Power and Propulsion Conference, 2007. VPPC 2007. IEEE 9-12 Sept. 2007, pp. 284-289
2-56
Breaker
Purpose Implement circuit breaker opening at current zero crossing
Library Elements
Description The Breaker block implements a circuit breaker where the opening and
closing times can be controlled either from an external Simulink signal (external control mode), or from an internal control timer (internal control mode).
A series Rs-Cs snubber circuit is included in the model. It can be connected to the circuit breaker. If the Breaker block happens to be in series with an inductive circuit, an open circuit or a current source, you must use a snubber.
When the Breaker block is set in external control m ode , a Simulink input appears on the block icon. The control signal connected to the Simulink input must be either 0 or 1 (0 to open the breaker, 1 to close it).
When the Breaker block is set in internal control mode, the switching times are specified in the dialog box of the block.
When the breaker is closed, it is represented by a resistance Ron. The Ron value can b e set as small as neces sary in order to be negligible compared with external components (a typical value is 10 mohms). When the breaker is open, it has an infinite resistance.
The arc extinction process is simulated by opening the breaker device when its current passes through 0 at the first current zero crossing following the transition of the Simulink control input from 1 to 0.
Operation Conditions
The Breaker closes when
The Breaker opens when
Control signal goes to 1 (for discrete systems, control signal must stay at 1 for at least 3 times the sampling period)
Control signal goes to 0 Breaker current passes through 0
2-57
Breaker
Dialog Box and Parameters
Note The Breaker block may not be the appropriate switching device to
use for DC circuits. For such applications, it is recommende d t hat you use the Ideal Switch block as a switching device.
2-58
Breaker r esistance Ron
The internal breaker resistance, in ohms (Ω). The Break er resistance Ron parameter cannot be set to 0.
Initial state
The initial state of the breaker. A closed contact is displayed in the block icon when the Initial state parameter is set to an open contact is displayed when it is set to
0.
1,and
If the breaker initial state is set to 1 (closed), the software automatically initializes all the states of the linear circuit and the Breaker block initial current, so that the simulation starts in steady state.
Snubber resistance Rs
The snubber resistance, in ohms (Ω). Set the Snubber resistance Rs pa ra m eter to
Snubber capacitance Cs
The snubber capacitance, in farads (F). Set the Snubber capacitance Cs parameter to
inf to get a resistive snubber.
Switching times
Specifies the vector of switchin g times when using the Bre ak er block in internal control m ode. At each switching time the Breaker block opens or closes depending on its initial state. For example, if the Initial state parameter is closes at the first switching time, opens at the second switchin g time, and so on. The Switching times para m eter is not visible in the dialog box if the External control of switching times parameter is selected.
inf to eliminate the snubber from the model.
0 to eliminate the snubber, or to
0 (open), the breaker
Breaker
External control of switching times
If selected, adds a Simulink input to the Breaker block for external control of the switching times of the breaker. The switching times are defined by a logical signal ( to the Simulink input.
Measurements
Select block terminals.
Select the Breaker block. If the snubber device is connected to the breaker model, the measured current is the one flowing through the breaker contacts only.
Branch voltage to measure the voltage across the B reaker
Branch current to measure the current flowing through
0 or 1) connected
2-59
Breaker
Select Branch voltage and current to measure the breaker voltage and the breaker current.
Place a Multimeter block in your m ode l to display the selected measurements during the simulation.
In the Available Measurements list box of the Multimeter block, the measurement is ide ntified by a label followed by the block name:
Measurement Label
Branch voltage Branch current
Limitations When the b lock is connected in s eries with an inductor or another
current source, y ou must add the snubber circuit. In most applications you can use a resistive snubber (Snubber capacitance parameter set to
inf) with a large resistor value (Snubber resistance para m eter set
to
1e6 or so). Because of modeling constraints, the internal breaker
inductance Ron cannot be set to 0.
Ub:
Ib:
You must use a stiff integration a lg orithm to simulate circuits with the Breaker block. best simulation spe ed.
For discretized models, the control signal must stay at 1 for a minimum of 3 sampling time periods to correctly close the Breaker block, otherwise the device stays open.
ode23tb with default parameters usually gives the
Example The power_breaker demo illustrates a circuit breaker connected in
series with a series RL circuit on a 60 Hz voltage source. The switching times of the Breaker block are controlled by a Simulink signal. The breaker device is initially closed and an opening order is given at t =
1.5 cycles, when current reaches a maximum. The current stops at
2-60
Breaker
the next zero crossing, then the breaker is reclosed at a zero crossing of voltage at t = 3 cycles.
Simulation produces the following re sults.
2-61
Breaker
Note that the breaker device opens only when the load current has reached zero, after the opening order.
See Also Three-Phase Fault
2-62
Brushless DC Motor Drive
Purpose Implement brushless DC motor drive using Permanent Magnet
Synchronous Motor (PMSM) with trapezoidal back electromotive force (BEMF)
Library Electric Drives/AC drives
Description
The high-level schematic shown below is built from six main blocks. The PMSM, the three-phase inverter, and the three-phase diode rectifier models are provided with the SimPow erSystems library. The speed controller, the braking chopper, and the current controller models are specific to the Electric Drives library. It is possible to use a simplified version of the drive containing an average-value model of the inverter forfastersimulation.
Note In SimPowerSystems software, the Brushless DC Moto r Drive block is commonly called the
AC7 motor drive.
2-63
Brushless DC Motor Drive
High-Level Schematic
Simulink Schematic
2-64
Speed Contr
oller
The speed co ntro ller is based on a PI regulator, shown below. The output of this regulator is a torque set point applied to the current controller block.
Brushless DC Motor Drive
Current Controller
The current controller contains four main blocks, shown below. These blocks are described below.
The T-I block performs the conversion from the reference torque to the peak reference current. The relation used to convert torque to current assumes pure rectangular current waveforms. In practice, due to the motor inductance, it’s impossible to obtain these currents. Therefore the electromagnetic torque may be lower than the reference torque, especially at high speed.
2-65
Brushless DC Motor Drive
The Hall decoder block is used to extract the BEM F information from the Hall effect signals. The outputs, three-level signals (-1, 0, 1), represent the normalized ideal phase currents to be injected in the motor phases. These type of currents will produce a constant torque. The following figure shows the BEMF of phase A and the output of the Hall decoder fo r the phase A.
The current regulator is a bang-bang current controller with adjustable hysteresis bandwidth.
2-66
Braking Chopper
The Switching control block is used to limit the inverter commutation frequency to a maximum value specified by the user.
When using the average-value inverter, the abc current references are sent to the simplified inverter.
The braking chopper block contains the DC bus capacitor and the dynamic b raking chopper, which is used to absorb the energy produced by a motor deceleration.
Brushless DC Motor Drive
Average-Value Inverter
The average-value inverter is shown in the following figure.
It is composed of one controlled current source on the DC side and of two controlled voltage sources on the AC side. The DC current source allows the representation of the DC bus current behavior described by the following equation:
with being the output AC power, the losses in the power electronic devices, and
On the AC side, the voltage sourcesarefedbytheinstantaneous voltages provided by the Trapezoidal PMSM dynamic model (see PMSM documentation for machine model). This dynamic model takes the reference currents (the rate of these currents has been limited to represent the real life currents), the measured BEMF voltages and the machine speed to compute the terminal voltages to be applied to the machine.
the DC bus voltage.
The dynamic rate limiter limits the rate of the reference currents when transitions occurs. The rate depends of the inverter saturation degree.
During loss of current tracking due to insufficient inverter voltage, the dynamicratelimitersaturates the reference current in accordance to this operation mode.
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Brushless DC Motor Drive
Remarks The model is discrete. Good sim ulati on results have been obtained with
a2 system has two different sampling times:
Speed controller sampling time
Current controller sampling time
The speed controller sampling time has to be a multiple of the current controller sampling time. The latter sampling time has to be a multiple of the simulation time step. The average-va lu e in verter allows the use of bigger simulation time steps since it does not gene rate small time constants (due to the RC snubbers) inherent to the detailed converter. For a current controller sampling time of 40 µs, good simulation results have been obtained for a simulation time step of 40 µs. The simulation time step can, of course, not be higher than the current controller time step.
time step. To simu late a digital controller device, the control
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Brushless DC Motor Drive
Dialog Box
PM Synchronous Machine Tab
The PM synchronous machine tab displays the parameters of the PM synchronous machine block of the powerlib library. Refer to Permanent Magnet Synchronous Machine for more information on the PM synchronous machine parameters.
Model detail level
Select between the detailed and the average-value inverter.
Mechanical input
Allows you to select eithe r the load torque or the motor speed as mechanical input. Note that if you select and apply a load torque, you will obtain as output the motor speed according to
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Brushless DC Motor Drive
the following differential equation that describes the mechanical system dynamics:
This mechanical system is included in the motor model.
However if you select the motor speed as mechanical input then you will get the electromagnetic torque as output, allowing you to represent externally the mechanical system dynamics. Note that the internal mechanical system is not used with this mechanical input selection and the inertia and viscous friction p arameters are not displayed.
See for example “Mechanical Coupling of Two Motor Drives”.
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Converters and DC Bus Tab
Brushless DC Motor Drive
fier section
Recti
The re the pa libr univ
rter section
Inve
The i the lib uni
ctifier section of the Converters and D C bus tab displays rameters of the Universal Bridge block of the powerlib
ary. Refer to the Universal Bridge for more information on the
ersal bridge parameters.
nverter section of the Converters and DC bus tab displays
parameters of the Universal Brige block of the powerlib
rary. Refer to the Universal Bridge for more information on the
versal bridge parameters.
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Brushless DC Motor Drive
The average-value inverter uses the following parameter.
On-state resistance
The on-state resistance of the inverter switches (ohms).
DC Bus Field — Capacitance
The DC bus capacitance (F).
Braking Chopper Section
Resistance
The braking chopper resistance used to avoid bus over-voltage during motor deceleration or when the load torque tends to accelerate the motor (ohms).
Frequency
The braking chopper frequency (Hz).
Activation Voltage
The dynamic braking is activated when the bus voltage reaches the upper limit of the hysteresis band. The following figure illustrates the braking chopper hysteresis logic.
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Deactivation Voltage
The dynamic braking is shut down whe n the bus voltage reaches the lower limit of the hysteresis band. The chopper hysteresis logic is shown in the following figure.
Controller Tab
Brushless DC Motor Drive
Regul
Sche
ation Type
This p regul
matic Button
When curr
op-up menu allows you to choose between speed and torque
ation.
you press this button, a diagram illustrating the speed and
ent controllers schematics appears.
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Brushless DC Motor Drive
Speed Controller section
Speed cutoff frequency
The speed measurement first-order low-pass filter cutoff frequency (Hz). This parameter is used in speed regulation mode only.
Speed controller sampling time
Thespeedcontrollersamplingtime(s). Thesamplingtimemust be a multiple of the simulation time step.
Speed Ramps — Acceleration
The maximum change of speed allowed during motor acceleration (rpm/s). An excessively large positive value can cause DC bus under-voltage. This parameter is used in speed regulation mode only.
Speed Ramps — Deceleration
The maximum change of speed allowed during motor deceleration (rpm/s). An excessively large negative value can cause DC bus overvoltage. This parameter is used in speed regulation mode only.
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PI Regulator — Proportional Gain
The speed controller proportional gain. This parameter is used in speed regulation m ode only.
PI Regulator — Integral Gain
The speed controller integral gain. Thi s parameter is used in speed regulation m ode only.
Torque output limits — Negative
The maximum negative demanded torque applied to the motor by the current controller (N.m).
Torque output limits — Positive
The maximum positive demanded torque applied to the motor by the current controller (N.m).
Brushless DC Motor Drive
Current Controller Section
Sampling Time
The current controller sampling time (s). The sampling time must be a multiple of the simulation time step.
Current controller hysteresis band
The current hysteresis bandwidth. This value is the total bandwidth distributed symmetrically around the current set point (A). The following figure illustrates a case where the current set point is Is
This parameter is not used when using the average-value inverter.
*
and the current hysteresis bandwidth is set to dx.
Block Inputs and Outputs
Note This bandwidth can be exceeded because a fixed-step simulation
is used. A rate transition block is needed to transfer data between different sampling rates. This block causes a delay in the gates signals, so the current may exceed the hysteresis band.
Maximum switching frequency
The maximum inverter switching frequency (Hz). This parameter is not used when using the average-value inverter.
SP
The speed or torque set p oint. Note that the speed set point can be a step function, but the speed change rate will follow the acceleration / deceleration ramps. If the load torque and the speed have oppos ite signs, the accelerating torque will be the sum of the electromagnetic and load torques.
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Brushless DC Motor Drive
Tm or Wm
The mechanical input: load torque (Tm) or motor s peed (Wm).
A, B, C
The three phase terminals of the motor drive.
Wm or Te
The mechanical output: motor speed (Wm) or electromagnetic torque (Te).
Motor
The motor measurement vector. This vector allows you to observ e the motor’s variables using the Bus Selector block.
Conv
The three-phase converters measurement vector. This vector contains:
The DC bus voltage
The rectifier output current
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The inverter input current
Note that all current and voltage values of the bridges can be visualized with the Multimeter block.
Ctrl
The controller measurement vector. This vector contains:
The torque refe rence
The speed error (difference between the speed reference ramp and actual speed)
The speed reference ramp or torque reference
Brushless DC Motor Drive
Model Specifications
The library contains a 3 hp drive parameter set. The specifications of the3hpdriveareshowninthefollowingtable.

3 HP Drive Specifications

Drive Input Voltage
Amplitude Frequency 60 Hz
Motor Nominal Values
Power Speed Voltage 300 Vdc
220 V
3hp 1650 rpm
Example The ac7_example demo illustrates an AC7 motor drive simulation with
standard load condition. At time t = 0 s, the speed set point is 300 rpm.
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Brushless DC Motor Drive
There are two design tools in this example. The first block calculates the gains of the speed regulator in accordance with your specifications. The second block plots the operating regions of the drive. Open these blocks for more information.
As shown in the following figure, the speed precisely follows the acceleration ramp. At t = 0.5 s, the nominal load torque is applied to the motor. At t = 1 s, the speed set point is changed to 0 rpm. The speed decreases to 0 rpm. At t = 1.5 s., the mechanical load passes from11N.mto-11N.m. Thenextfigureshowstheresultsforthe detailed converter and for the average-value converter. Observe that the average voltage, current, torque, and speed values are identical for both models. Notice that the higher frequency signal components are not represented with the average-value converter.
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AC7 Example Waveforms (Blue: Detailed Converter, Red: Average-Value Converter)
Brushless DC Motor Drive
References [1] Bose, B. K., Modern Power Electronics and AC Drives,Prentice-Hall,
N.J., 2002. [2] Krause, P. C., Analysis of E lectric Machinery, McGraw-Hill, 1986. [3] Tremblay, O., Modélisation, simulation et commande de la machine
synchrone à aimants à force contre-électromotrice trapézoïdale,École de Technologie Supérieure, 2006.
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Connection Port
Purpose Create Physical Modeling connector port for subsystem
Library Elements
Description The Connection Port block, placed inside a subsystem composed of
SimPowerSystems blocks, creates a Physical Modeling open round connector port connection line, the port becomes solid the solid port
You connect individual SimPowerSystems blocks and subsystems made of SimPowerSystems blocks to o ne another with SimPowerSystems connection lines, instead of regular Simulink signal lines. These are anchored at the open, round connector ports of SimPowerSystems blocks automatically have such open round connector ports. You can add additional connector ports by adding Connection Port blocks to your subsystem.
Dialog Box and Parameters
on the boundary of the subsystem. Once connected to a
. O nce you begin the simulation,
becomes a n electrical terminal port, an open square .
. Subsystems constructed
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Port n
Port
umber
ield labels the subsystem connector port created by the
This f
. Multiple connector ports on the boundary of a single
block
ystem require different numbers as labels. The default value
subs
hefirstportis
for t
location on parent subsystem
se which side of the parent subsystem boundary the port is
Choo
ced on. The cho ices are
pla
1.
Left or Rig ht. The default is Left.
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