ST ISV005V2 User Manual

STEVAL-ISV005V2

240 W photovoltaic battery charger based on the SPV1020

Features

■PWM mode DC-DC boost converter

■Duty cycle controlled by MPPT algorithm with 0.2% accuracy

■Operating voltage range 0-40 V

■Overvoltage, overcurrent, overtemperature protections

■Built in soft-start

■Up to 98% efficiency

■Automatic transition to burst mode for improved efficiency at low solar radiation

■SPI interface

■Output current limitation

■RoHS compliant

Description

The STEVAL-ISV005V2 demonstration board is mainly based on the SPV1020 device, a monolithic DC-DC boost converter designed to maximize the power generated by photovoltaic panels independently of temperature and amount of solar radiation.

The optimization of the power conversion is obtained with an embedded logic which performs the MPPT (max power point tracking) algorithm on the PV cells connected to the converter.

One or more converters can be housed in the connection box of the PV panels, replacing the bypass diodes. Since the maximum power point is locally computed, the efficiency at system level will be higher than that of conventional topologies, where the MPP is computed in the main centralized inverter.

For a cost-effective application solution and miniaturization requirements, the SPV1020 embeds the power MOSFETs for active switches and synchronous rectification, minimizing the number of external devices. Furthermore, the

Data brief

4-phase interleaved topology of the DC-DC converter renders unnecessary the use of electrolytic capacitors, which would severely limit the lifetime.

The SPV1020 works at fixed frequency in PWM mode, where the duty cycle is controlled by the embedded logic running a “Perturb & Observe” MPPT algorithm. The switching frequency, internally generated and set by default at 100 kHz, can be tuned externally, while the duty cycle ranges from 5% to 90% with a step of 0.2%.

Safety of the application is guaranteed by stopping the drivers in case of output overvoltage or overtemperature.

The bypass diodes SPV1001N40 guarantee very high application efficiency even when the PV panel voltage is lower than the UVLO threshold of the SPV1020 (6.5 V) and the connection is in series consisting of two or more PV panels.

The SEA05 is connected to the output stage of the application and is used to implement the output current limitation (not available with the SPV1020 alone) through the current sensing resistors R9 and R10.

February 2012	Doc ID 022746 Rev 1	1/4
For further information contact your local STMicroelectronics sales office.		www.st.com

2/4

Figure

1

Circuit

6BATT

9,1

'

639 1

-

)$6721

9B287

'

6736 8

17

9&&

'

&

&

'

639 1

-

&

60% &$

'

X)

X)

X)

60% &$

5 P 2KP

&

9EDWW

&211 )/(;

X )

&%

&%

17

9,1

&

Q)

/

/

&

Q)

9,1

- )$6721

/

X+

X+

/

6BATT

9,1

)OUT?MAX6

SENSEE2N

schematicISV005V2STEVALcircuit1-.

schematicCircuit

schematic

-

9B287

9B287

5

&

X)

&%

&%

&

X)

0

022746 ID Doc

/

/

0'.$

0'.$

9,1B616

/

/

-

&

X)

&%

&%

&

X)

9B287

9B287

&

S)

3(5430)?8#3

',$* 63,B'$7$B287

5

4%34?30)?$!4!.$!4!?)

9UHJ

&

Q)

N

4%34?#,+30)?#,+

26&B,1

5

26&B,1

5

GQP

',$* 63,B'$7$B287

9&&

9287B616

5

N

& Q)

3%!)CTRLLPINTO

3%!)SNS)PINTO

Rev

9,1B616

3=B287

9287B616

6).?3.3?-

6).?3.3?-

!'.$

& S)

+($'(5

639 3662 SDFNDJH

1

9,1

/

9,1

/

X+

/

X+

/

&

&

Q)

&%

&%

Q)

34 3/,!2 +%9 02/$5#4#,EGEND

&

Q)

5

N

9B287

' 5 /('

5 N

& Q)

5 .

9UHJ

3=B287

306.

306

5 0

2%$%,%$ ON /UTPUTN,IMITAIONUIS 4RIGGERED

6CTRLL 6

6BATTAT6

-

& Q)

(IGH #URRENT 0ATHH,EGEND

6($&9 && FRQWUROOHU

STEVAL

5

N

)SNS

9B287

9EDWW

9EDWW

3=B287

)INIPATH

9287B616

6CTRL

)CTRL

6OUT?SNS?S6

'ROUND PATH

6BATTAT6

5

N

)LOAD PATH

9EDWW

ISV005V2-

)LOAD PATH

V-!