The SPD Laboratory, Inc. has developed its first generation PV Power Analyzer VKPA-25 (currently discontinued) with built-in Maximum Power Point Tracking (MPPT)
function in 2015, and then delivered to Prof. Segawa Group at the RCAST, Universityof Tokyo. By utilizing this, Prof. Satoshi Uchida has patiently continued his researchon perovskite solar cell (PSC) hysteresis and used MPPT technique to evaluate thePSC performance for the first time (PSCO-2015, Sep. 25, EPFL; Chem. Lett. 2015, 44, 1750-1752).
The announcement was new to everyone's memory. In particular, it was significant toclarify that the hysteresis of a stacked PSC was caused by its capacitance component
inside and to make the skeptical researchers mostly from Europe acknowledge its
existence. Also, the MPPT has been gradually used in the real evaluation of solar cell
performance, different from the conventional I-V curve method, where all of the SPD
Lab’s power analyzers have built-in advanced MPPT algorithms driven in firmware
level by maintaining the cell at the maximum output conditions.

SPD Laboratory, Inc.
Hamamatsu, 432-8011, JAPAN
Tel: +81-53-474-7901
Fax: +81-53-401-7080
Email: inq@spd-lab.com
Web: http://www.spdlab.com

VK-MPA-100

VK-PA-100

Measure Range:

Voltage: ±10 V to ±30 mV
Current: ±1 A to ±6 μA

Maximum Measuring
Resolution:

Voltage: 2 μV (16-bit ADC)
Current: 14 nA (16-bit ADC)

Communication
Functions::BluetoothI-V Tracer, MPPT, Potentiostat/Galvanostat, 4 Quadrant I-V, 4 Probe ΩAutomatic Light intensity measurement

For More Details:

http://www.spdlab.com/English/VK-PA100.html

Measure Range:

Maximum Measuring
Resolution
Number of Channels
CommunicationFunctions::::For More Details:VK-PA-300

Measure Range:

Maximum Measuring
Resolution
Communication
Functions:::

For More Details:

Voltage: ±12 V to ±150 mV
Current: ±4 A to ±6 μA
Voltage: 9 nV (24-bit ADC)
Current: 0.8 pA (24-bit ADC)
BluetoothI-V Tracer with automatic curve fitting,
MPPT, Potentiostat/Galvanostat, Cyclic
Voltammetry (CV) with automatic area
calculation
http://www.spdlab.com/English/VK-PA300.html

VK-PA-1000

Measure Range:

Voltage: 100 V to 500 mV (8 ranges)
Current: 1 A to 50 μA (15 ranges)

Maximum Measuring
Resolution:

Voltage: 62 nV (24-bit ADC)
Current: 12 pA (24-bit ADC)

Communication
Functions::

For More Details:

BluetoothI-V Tracer with automatic curve fitting,
MPPT, Programmable electronic load.
http://www.spdlab.com/English/VK-PA1000.html

VK-PA-8000

Measure Range:

Maximum Measuring
Resolution
Communication
Functions:::

For More Details:

Voltage: ±20 V to ±250 mV
Current: ±8 A to ±15 μA(±10 A Pulse)
Voltage: 19 nV (24-bit ADC)
Current: 2 pA (24-bit ADC)
BluetoothI-V Tracer with automatic curve fitting,
MPPT, Potentiostat/Galvanostat, Cyclic
Voltammetry (CV) with automatic area
calculation
http://www.spdlab.com/English/VMK8000.html

Voltage: ±10 V to ±100 mV (6 ranges)
Current: ±1.2 A to ±20 μA (16 ranges)
Voltage: 16 nV (24-bit ADC)
Current: 3 pA (24-bit ADC)
6 (PV), 4 (Light Intensity), 1 (Temperature)
BluetoothI-V Tracer with automatic curve fitting,
MPPT, Programmable electronic load,
Continuous plotting of light intensity andtemperature graphs
http://www.spdlab.com/English/VK-MPA100.html

VK-PA-PicoMeasure Range:Maximum Measuring
Resolution:

Communication
Functions::

For More Details:

Voltage: ±10 V to ±80 mVCurrent : ±5 mA to ±600 pA
Voltage: 2 μV (16-bit ADC)
Current: 17 fA (16-bit ADC)
Bluetooth
Pico Ammeter, Potentiostat, I-V Tracer,
MPPT, 4 Quadrant I-V
http://www.spdlab.com/English/VK-PAPico.html

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(1)

True Maximum Power Point Tracking (MPPT) Function:2

 Determination of true conversion efficiency of asolar cell is impossible with the I-V curve when itshows hysteresis effect.
 MPPT is the way to extract true maximum
output power and efficiency of solar cell withtime.
 Taking series of I-V curves with a given timeinterval and then plotting the calculated Pmax
against time will NOT solve the issue. Becauseof all I-V curves have two different Pmax values
for forward and reverse I-V.
 Our VK-PA series analyzers have built-in
advanced MPPT algorithm driven in firmware
level which can continuously maintain the cell at
maximum output conditions.

 Our user-friendly software interface offers
maximum flexibility to set searching and tracking
parameters.
 Measured power conversion efficiency, maximum
output power, voltage, current, and total energy
are plotted against time on an auto-scaling graph.
Users can view I vs. V plot on a separate graphduring MPPT.
 Optimized two step MPPT algorithm (initialsearching and tracking) used in our analyzers
capable of quickly reaching and keep tracking MPP
without oscillatory behavior.
 Four different conditions can be conveniently
used to automatically stop the tracking process
when condition satisfied.

 Our VK-PA-300 and VK-PA-8000 analyzers offer
two different maximum power point searching
methods.
 “Linear” tab for “Hill climbing algorithm” to findthe maximum power point.

 “Bisection” tab for “Bisection algorithm” to findthe maximum power point.

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 Results of independent measurement on MPPT performed by Prof. Satoshi Uchida’s group at RCAST,
University of Tokyo shows the comparison between SPD Lab VK-PA-Pico and Keysight + add-in-software
measuring systems.

4(2) I-V Tracing Function:
 All of our PV Analyzers offer conventional I-V
tracing function with following capabilities.

 “Auto Reverse” option allow user to plot forward
and reverse I-V on same graph and analyze
hysteresis effects.

 User can set start, stop, step and select one ofthree different scan methods.

 Advanced I-V and “Programmed Continuous I-V”
options are available.

Automatic curve fitting function is applicable to fit the I-V data with two diode model and calculate variousparameters.

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Calculated fitting parameters. This will show the difference of parameters calculated form the fitted curveand direct I-V data.
(This function is available on VK-PA-300 and VK-PA-8000 )(3)

Advanced I-V Tracing Function:

 This function allows user to change thefollowing settings during I-V tracing andobserve transient behavior of the cell.
1. Start point holding time
2. End point holding time
3. Current vs. time plot (I-t) for eachdata point
4. I-t plot for given fixed voltage in the
middle of I-V curve.

6(4) Pico Ammeter Function:
 Pico ammeter function allow user to measuretrue short circuit current of PV device with 0 V
voltage drop across the PV device.
 Analyzer uses trans-impedance amplifier with lessthan 4 μV offset and 0.015 μV/C˚ offset drift toperform this operation.
 VK-PA-Pico can reach the maximum measurement
resolution of 17 fA.

 Two automatic calibration functions allow user tonull the thermoelectric current generated from
dissimilar metal contacts in the circuit andmeasure only the photo current.

(This function is available on VK-PA-Pico only)(5) Potentiostat /Galvanostat Function: Potentiostat function allow user to set the desired
constant voltage across the sample and measure
voltage current, resistance , and power.
 Galvanostat function (except VK-PA-Pico) allow user
to set the desired constant current through thesample and measure voltage, current, resistance ,and power.
 User can plot voltage , current, and power withthe time under the given set voltage or current.

 “Plot Voc and Isc” special function allows user toplot the behavior of solar cell when it switchedfrom open circuit to the short circuit condition andbackward condition intermittently.

7(6) Cyclic Voltammetry Function:
 This function allow user to plot CV curve of asample.
 User can set the following parameters.

4-WIRESENSE

INPUT/OUTPUTHIHILOLO The inside area of each curve is automaticallycalculated by the anlyzer software.

 User can use two or three electrode configuration
to connect sample with the analyzer.

Screen shot of a Cyclic Voltammetry curve showing calculated absolute area inside each cycle

(7) Data Saving Options: The control software of our PV analyzer
canautomaticallygenerate
fully
formatted Microsoft Excel workbookwith data and graph.

 Text file (.txt) and comma separated text(.csv) format file saving is also possible.

Example of Excel file for I-V data generated from VK-PA-300

89(8) Advanced User Settings:
 Our analyzers allow more flexibility to modify andmonitor hardware .

 Timing diagram will show you the details of realtiming of voltage set point and data reading point.

 User has access to change the integration time ofAnalog to Digital Converter (ADC).

 Analyzer can be “Reset” using the software
button remotely.
 Four or two wires configuration can be selected.

(9) Wireless Bluetooth Connection:
 Control command and data communication
between PV analyzer and a computer isestablished by a Bluetooth communication.
 There is no wire connections between PV power
analyzer and the computer where you installed
the control software.
 User can conveniently place PV analyzer andcomputer in a two separate places in thelaboratory.

08/12/20