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November 2012 Doc ID 16555 Rev 3 1/55
AN3095
Application note
STEVAL-ISV002V1, STEVAL-ISV002V2 3 kW
grid-connected PV system, based on the STM32F103xx
Introduction
The STEVAL-ISV002V2 demonstration board is the same as the STEVAL-ISV002V1, but
assembled in a metal suitcase. In recent years, the interest in photovoltaic (PV) applications
has grown exponentially. As PV systems need an electronic interface to be connected to the
grid or standalone loads, the PV market has started appealing to many power electronics
manufacturers. Improvements in design, technology and manufacturing of PV inverters, as
well as cost reduction and high efficiency, are always the main objectives, [see References
1, 2].
This application note describes the development and evaluation of a conversion system for
PV applications with the target of achieving a significant reduction in production costs and
high efficiency. It consists of a high frequency isolated input power section performing DC-
DC conversion and an inverter section capable of delivering sinusoidal current of 50 Hz to
the grid. The system operates with input voltages in the range of 200 V to 400 V and is tied
to the grid at 230 Vrms, 50 Hz, through an LCL filter. Other peculiar characteristics of the
proposed converter are the integration level, decoupled active and reactive power control
and flexibility towards the source. A prototype has been realized and a fully digital control
algorithm, including power management for grid-connected operation and an MPPT
(maximum power point tracking) algorithm, has been implemented on a dedicated control
board, equipped with a latest generation 32-bit (STM32F103xx) microprocessor.
Figure 1. 3 kW PV system image
www.st.com
