STEVAL-ISV003V1 #2: 250W Solar Microinverter, MPPT


The STEVAL-ISV003V1 is a demonstration board which implements the microinverter concept and is designed to optimize the power production of each single solar panel by means of DC/AC conversion. The conversion system is capable of both grid synchronization and Maximum Power Point Tracking (MPPT) thanks to the use of an advanced control algorithm implemented in the 32-bit STM32 microcontroller. The MPPT function is based on the perturb and observe (P & O) concept which seeks the best operating point of the panel, thus maximizing the energy produced under any environmental condition. The grid synchronization algorithm has the advantage over standard solutions of a decoupled control of active and reactive power. The STEVAL-ISV003V1 demonstration board uses a high-frequency (HF) isolated DC/DC converter with interleaved current and an optimized full-bridge DC/AC inverter. The typical solar panel voltage is first stepped up to about 400 V and then converted into AC to create a sinusoidal output.

An LED display provides a user-friendly interface for the end user which allows monitoring and/or modifying some of the main operating parameters. Two modes of operation are available and can be selected to allow either open-loop operation or closed-loop operation in synchronization with the grid.

In open-loop mode the sinusoidal reference is created internally by means of a standard lookup table, while in closed-loop mode, a sinusoidal voltage feedback, proportional to the grid voltage, is used. The system can be connected to either a 50 Hz or 60 Hz network, depending on local requirements. Finally, the RS-232 interface can be used for serial data transfer of specified voltage, current and current signals.


  • 250 W power capability

  • Input voltage range from 18 V to 45 V

  • Output voltage Vout= 230Vac 50Hz -240Vac 60Hz

  • Grid connection algorithm and MPPT capability

  • MPPT efficiency (99%)

  • Decoupled control of active and reactive power

  • Overcurrent and anti-islanding protection

  • RS-232 for communication

  • Galvanic isolation between the panel and the grid


Manufacturer STMicroelectronics
Category Energy Harvesting
Sub-Category Solar Inverter
Eval Board Part Number 497-12941-ND
Eval Board Supplier STMicroelectronics
Eval Board Board not Stocked
Output Power 250 W
Voltage Out @ Frequency 110 ~ 240 V @ 50/60 Hz
Voltage In 18 ~ 45 V
Features Anti-Islanding Protection
Grid Connectable
Over Current Protection
Efficiency @ Conditions >95%, 20 ~ 40V in, 380V @ 75 ~ 250 W
>93%, 380V in, 240 VAC @ 75 ~ 250 W
Component Count + Extras 342 + 16
Design Author STMicroelectronics
Switching Frequency 17 kHz
35 kHz
Application / Target Market
Main I.C. Base Part STM32F103ZE
Date Created By Author
Date Added To Library 2013-05