Switching Frequency Limited Hysteresis Based Voltage Mode Control of Single-Phase Voltage Source Inverters

Abstract

This paper proposes a new control strategy for single-phase voltage source inverters that does not rely on switching based on Pulse Width Modulation. The technique is similar to conventional current hysteresis control, but instead of the output current, the low-pass-filtered inverter output voltage is utilised as the feedback signal. Nevertheless, the switching instants are not determined by a predefined band, but rather by a low-cost Complex Programmable Logic Device (CPLD)-based control logic, which ensures a nearly constant switching frequency. Similar to hysteresis-based control methods, the proposed method ensures a rapid dynamic response. Notable characteristics of the proposed method include a quick dynamic response, a well-defined harmonic spectrum, and an improved total harmonic distortion (THD), particularly during load current and source voltage changes. The proposed method is implemented on a 1 kW, 230 V, 50 Hz prototype. Simulation and experimental results are presented to validate the proposed concept, which demonstrates a superior dynamic response and enhanced THD during load and source voltage variations.