A unified approach to dual-mode synchronous overmodulation regulation of PWM inverters with constant and variable fundamental frequencies

Abstract

This paper presents a brief overview of methods and algorithms for synchronous overmodulation regulation of power electronic systems (variable-speed electric drives and photovoltaic (PV) installations) based on modulated voltage source inverters (VSINs). These inverters are controlled using synchronous space-vector pulse-width modulation (SSV PWM), which ensures synchronization and symmetry of the output voltage of power electronic systems with both constant (PV stations) and variable (AC electric drives) fundamental frequencies. In this case, dual-mode overmodulation control of PWM inverters is based on modified control correlations. Specifically, these correlations include two special overmodulation coefficients, defined as functions of two modulation threshold indices for PV inverters and two threshold frequencies for drive inverters. Simulations demonstrate the behavior of these inverter-based power conversion systems operating at increased modulation indices of PWM inverters.