Generalised design methodology of second-order filters for voltage-source inverters with space-vector modulation

Abstract

The paper presents a systematised and generalised methodology of second-order output filter for inverters that synthetise sinusoidal voltage waveforms through space-vector pulse-width modulation (PWM). The objective of this methodology is to determine the largest natural frequency of the filter that ensures specification of the maximum total harmonic distortion (THD) admissible in the output voltages of the PWM inverter. The proposed methodology is discussed in detail, including the description of the steps needed to derive the design procedure for different topologies of voltage inverters, and the procedure for obtaining the design curves. To illustrate the use of the proposed methodology, detailed design procedures are given for single-phase, three-phase three-wire and three-phase four-wire filter topologies. Finally, examples are presented which include experimental results demonstrating the validity of the proposed design methodology.