Optimisation of Output Filters for Inverter Fed Drives

This paper presents a detailed analysis and optimisation of output filters for inverter fed drives. The goal is to minimise the total cost of the filter components when the maximum deviation of the fundamental output voltage and the minimum suppression of harmonic voltages are given. The analysis is based on the full equivalent circuit diagram of induction machines and thus covers all possible load states of the drive. Besides simple LC filters, a fourth order LCLC filter and an LC filter with additional band rejection are discussed