Performance of a cascaded multilevel H-bridge series voltage compensation system under multiple loop control strategy

In this paper, the performance of a cascaded multilevel H-bridge converter for a series voltage compensation system under multiple loop control strategy (MLCS) is investigated. The control method employs the voltage and current of the capacitor of the output LC filter of the converter as the feedback signals to generate the reference signal for the converter. The contribution of each voltage source inverter (VSI) cell to the total output capacitor current is calculated and the frequency response for the series voltage compensation system is investigated, for a cascaded five-level H-bridge topology. The effects of the gains of the controller used in the feed-forward path of both the capacitor current loop and capacitor voltage loop on the THD of the compensated load voltage are investigated using the response surface methodology (RSM), leading to the selection of optimum gain values. Finally, simulation results are presented to validate the performance of the MLCS for reducing load voltage disturbances through series voltage compensation.