Design and implementation of an inverter output LC filter used fordv/dt reduction

摘要

This paper presents the design and analysis of a LC output filternfor use with IGBT-based motor drive inverters. The LC filter is used tonlimit the rate of rise of the inverter output voltage and reduce commonnmode noise to the motor. In typical applications where dv/dt is limitednto 100-500 V/Μs, the resonant frequency of the filter is above thenswitching frequency. A diode bridge must therefore be used to clamp thenresonant voltage. Resistors are also used to help dissipate the energynstored in the resonant circuit. Crucial to the design of the filter isnthe handling of the additional losses in the filter. The paper describesnthe design considerations for such a filter for use in a 460 V inductionnmotor drive. The losses in the circuit are estimated to show thenlimitations of the filter. Experimental results illustrate the controlnof dv/dt at the inverter terminals, and the reduced peak voltage at thenmotor end of a long cable