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Revision History
January 1998First printingVersion 1.0 (Release 10)
September 2000 Second printingRevised for Version 2.1 (Release 12)
June 2001Online onlyRevised for Version 2.2 (Release 12.1)
July 2002Online onlyRevised for Version 2.3 (Release 13) (Renamed from Power
System Blockset User’s Guide)
February 2003Third printingRevised for Version 3.0 (Release 13SP1)
June 2004Online onlyRevised for Version 3.1 (Release 14)
October 2004Fourth printingRevised for Version 4.0 (Release 14SP1)
March 2005Online onlyRevised for Version 4.0.1 (Release 14SP2)
May 2005Online onlyRevised for Version 4.1 (Release 14SP2+)
September 2005 Online onlyRevised for Version 4.1.1 (Release 14SP3)
March 2006Online onlyRevised for Version 4.2 (Release 2006a)
September 2006 Online onlyRevised for Version 4.3 (Release 2006b)
March 2007Online onlyRevised for Version 4.4 (Release 2007a)
September 2007 Online onlyRevised for Version 4.5 (Release 2007b)
March 2008Online onlyRevised for Version 4.6 (Release 2008a)
October 2008Online onlyRevised for Version 5.0 (Release 2008b)
March 2009Online onlyRevised for Version 5.1 (Release 2009a)
September 2009 Online onlyRevised for Version 5.2 (Release 2009b)
March 2010Online onlyRevised for Version 5.2.1 (Release 2010a)
transformer with taps
Mutual InductanceImplement inductances with mutual
coupling
NeutralImplement common node in circuit
Parallel RLC BranchImplement parallel RLC branch
Parallel RLC LoadImplement 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 BranchImplement series RLC branch
Series RLC LoadImplement linear series R LC load
Surge Arrester
DiodeImplement diode model
GTOImplement gate turn off (GTO)
Power Electronics
thyristor model
Machines
Ideal Switch
IGBT
IGBT/DiodeImplements
MOSFETImplement
Three-Level BridgeImplement three-level neutral point
ThyristorImplement thyristor model
rsal Bridge
Unive
Asynchronous MachineModel 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 MachineImplement wound-field or
permanent magnet DC machine
Excitation SystemProvide 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 MachineModel the dynamics of simplified
Single Phase Asynchronous MachineModel the dynamics of single
Steam Turbine and GovernorModel 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 MotorModel the dynamics of switched
Synchronous MachineModel 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 DriveImplement brushless DC motor
drive using Permanent Magnet
Synchronous Motor (PMSM) with
trapezoidal back electromotive force
(BEMF)
DTC Induction M otor DriveImplement 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 DriveImplement six -ste p inverter fed
Induction Motor Drive
Space Vector PWM VSI Induction
Three-Phase V-I MeasurementMeasure three-phase currents and
Voltage MeasurementMeasure 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 TransformationPerform Park transformation from
three-phase (abc) reference frame to
dq0 reference frame
Active & Reactive Power
dq0_to_abc TransformationPerform Park transformation from
Fourier
RMSMeasure root mean square (RMS)
Three-Phase Sequence Analyzer
Total Harmonic DistortionMeasure 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 GeneratorGenerate 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
PurposePerform Park transformation from three-phase (abc) reference frame to
dq0 reference frame
LibraryExtras/Measurements
A discrete version of this block is available in the Extras/Discrete
Measurements library.
DescriptionThe 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
ExampleThe 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 Alsodq0_to_abc Transforma tion
2-7
AC Current Source
PurposeImplement sinusoidal current source
LibraryElectrical Sources
DescriptionThe 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 AvailableMeasurements 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
MeasurementLabel
Current
Isrc:
ExampleThe 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 AlsoControlled Current Source, M ultimeter
2-10
Active & Reactive Power
PurposeMeasure active and reactive pow ers of voltage-current pair
LibraryExtras/Measurements
A discrete version of this block is available in the Extras/Discrete
Measurements library.
DescriptionThe 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.
ExampleThe 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
PurposeImplement sinusoidal voltage source
LibraryElectrical Sources
DescriptionThe 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 AvailableMeasurements list box of the Multimeter block, the
measurement is identified by a label followed by the block name.
Voltage tomeasurethevoltageacrosstheterminalsof
MeasurementLabel
Voltage
Usrc:
ExampleThe 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 AlsoControlled Voltage Source, DC Voltage Source, Multimeter
2-16
Asynchronous Machine
PurposeModel the dynamics of three-phase asynchronous machine, also known
as induction machine
LibraryMachines
DescriptionThe 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:
SubscriptDefinition
dd axis quantity
q
r
s
lLeakage 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):
ParameterDefinition
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
ParameterDefinition
Asynchronous Machine
Vqs,i
V’qr,i’
Vds,i
V’dr,i’
ϕqs, ϕ
ϕ’qr, 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
SynchronousΘ
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):
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 DefinitionUnitsSymbol
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
Aorpui’
Aorpui’
Aorpui’
Aorpui’
Aorpui’
V.s or pu
V.s or pu
Vorpu
Vorpu
Stator current is_aA or pu
Stator current is_bA or pu
ϕ’
ϕ’
v’
v’
i
i
ra
rb
rc
qr
dr
qr
dr
qr
d
sa
sb
2-28
Asynchronous Machine
Signal DefinitionUnitsSymbol
12
13
14
15
16
17
18
19
20
21
Stator current is_cA or pu
Stator current is_qA or pu
Stator current is_dA 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 speedrad/s
Electromagnetic torque Te
N.m or puT
Rotor angle thetamrad
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
Limitations1 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.
ExamplesExample 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 ParametersMeasurements
Vsat (Vrms L-L)Isat (peak A)Vrms L-LIs_A (peak A)
-23014.0423014.03
--
-32227.
--
81
1207.322
25016.86
30024.04
32228.
35135.22
39
2-35
Asynchronous Machine
Saturation ParametersMeasurements
Vsat (Vrms L-L)Isat (peak A)Vrms L-LIs_A (peak A)
-414
--
-46072.6946073.01
--
-50697.98506100.9
--
--
-552148.68552146.3
--
-598215.74598216.5
--
-644302.98644313.2
--
--
-690428.78690432.9
53.79
38243.83
414
42658.58
44967.94
47279.12
48888.43
519111.6
535126.9
546139.1
569169.1
581187.4
620259.6
633287.8
659350
672383.7
681407.9
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 AlsoPowergui
2-38
Battery
PurposeImplement generic battery model
LibraryElectrical Sources, E lectric Drives/Extra Sources
DescriptionThe 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 PlotDischarge 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,theNominalVoltage 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 NominalDischarge 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 Capacity6.5 Ah
eter
Value
h
6.5 A
2mΩ
(a)
1.18 V
2-49
Battery
ParameterValue
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 DefinitionUnits
SOCThe 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.
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
PurposeImplement circuit breaker opening at current zero crossing
LibraryElements
DescriptionThe 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.
OperationConditions
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:
MeasurementLabel
Branch voltage
Branch current
LimitationsWhen 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
ExampleThe 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 AlsoThree-Phase Fault
2-62
Brushless DC Motor Drive
PurposeImplement brushless DC motor drive using Permanent Magnet
Synchronous Motor (PMSM) with trapezoidal back electromotive force
(BEMF)
LibraryElectric 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:
withbeing 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.
2-67
Brushless DC Motor Drive
RemarksThe 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
2-68
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
2-69
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”.
2-70
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.
2-71
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.
2-72
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.
2-73
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.
2-74
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.
2-75
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
2-76
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
Frequency60 Hz
Motor Nominal
Values
Power
Speed
Voltage300 Vdc
220 V
3hp
1650 rpm
ExampleThe 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.
2-77
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.
2-79
Connection Port
PurposeCreate Physical Modeling connector port for subsystem
LibraryElements
DescriptionThe 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
2-80
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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