Decreasing the Single-Phase Inverter Output Voltage Distortions Caused by Impedance Networks

This article presents the possibility of decreasing the inverter output voltage distortions that are caused by the typical distortions in the output voltage pulses of an impedance network using the qZ-source as an example. DC sources, such as photovoltaic cells with the qZ-source, increase the dc voltage; an impedance network operates in the continuous current mode and the discontinuous current mode (DCM). Both of these, but particularly DCM, implement the characteristic distortions to the impedance network output pulses, which results in the distortions in the inverter output voltage. It is possible to decrease these distortions in a passive way (increasing the capacitors of the network) or by using an efficient instantaneous controller of the inverter output voltage. Two controllers - a single-input single-output PID controller and a multi-input single-output improved passivity-based controller - were compared using the experimental model voltage source inverter with the input qZ-source.