STEVAL-ISV003V1

概要

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 the monitoring and/or modifying of 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 which is proportional to the grid voltage is used. This system can be connected to a 50 Hz network (STEVAL-ISV003V1) and to a 60 Hz network (STEVAL-ISV003V2), based on local requirements. The RS-232 interface can be used for serial data transfer of specified voltage, current and current signals.