Digital Hysteresis Control Algorithm for Switched Inductor Quasi Z-Source Inverter with Constant Switching Frequency

Abstract

In this paper, a digital hysteresis current limit controller is developed for Switched Inductor Quasi Z-Source Inverter (SLQZSI). Traditional methods like hysteresis current fixed limit and adjustable hysteresis current limit techniques changes the hysteresis bandwidth in accordance to modulating frequency and gradient of reference current. The operating shifting frequency of typical approaches oscillates and crosses the intended steady shifting frequency under noise. It leads to undesirable heavy interference between the phases and more power loss. In the planned digital hysteresis current limit technique, the hysteresis current limit is calculated by resolving the optimization problem. In the proposed approach the operating shifting frequency is kept same or inferior to the intended steady shifting frequency even under noise. Hence the planned digital hysteresis current limit algorithm maintains the output current steady and power loss is minimized which is not promised by the conservative techniques. To compare different control strategies in terms of nature of operating switching frequency and harmonic performance simulations are built on the MATLAB/SIMULINK