Passive power decoupling approach for three-level single-phase impedance Source Inverter based on resonant and PID controllers

Single-phase inverter suffers from double-frequency power ripples in the input side transferred there from the ac-side. To mitigate this ripple, two types of power decoupling approaches can be applied: passive power decoupling and active power decoupling. We present a technique of passive power decoupling realized by modifying the control strategy. The main idea is to produce the time-varying shoot-through duty cycle to charge and discharge impedance capacitors when needed in the desired sequence for mitigating input power ripple without deteriorating the output power quality. The main contribution of the paper is in the determination of the parameters of a regulator taking into account the dynamic feature of the quasi-Z-source network. The validity of the proposed control strategy was confirmed by simulation results in PSCAD. The results show that this strategy can be applied for practical applications.