Variable switching point predictive current control of quasi-Z-source inverters

Abstract

<p>This paper presents a variable switching point predictive current control (VSP<sup>2</sup>CC) for the quasi-Z-source inverter (qZSI). The proposed VSP<sup>2</sup>CC aims to regulate the current on the ac side as well as the inductor current and capacitor voltage of the quasi-Z-source network. Unlike the previously presented model predictive control (MPC) strategies for the qZSI, with the proposed control scheme the optimal switch position can be changed at any time instant within the sampling interval. By doing so, the shoot-through state can be applied for a shorter time than the sampling interval which in turn results in lower output and inductor currents ripples. Experimental results, based on an FPGA, are provided to verify the proposed control technique. As it is shown, in comparison with the conventional MPC, the proposed method results in lower inductor current ripples and less output current THD.</p>