Analytical Modeling of Ripple Currents in a Drive Inverter with a LC Sine Wave Filter

In this work an analytical calculation method to obtain ripple current waveforms in inverters with sine wave filters is presented. Those are represented as piece-wise linear (PWL) waveforms. The main advantage of calculated PWL waveforms is the faster computation compared to conventional circuit simulation. Furthermore a lot of analytical loss models for passive filter components and for the semiconductors require PWL waveforms. The presented method is validated with a circuit simulation. Then a design example is given, where the calculated PWL current waveforms of a two level voltage source inverter (VSI) are applied to a semiconductor loss model. The influence of the inductance value on the semiconductor losses is investigated.