Performance evaluation of GaN FET-based matrix converters with dv/dt filters for variable frequency drive applications

Abstract

This paper evaluates the dv/dt performances of the motor input terminal fed by a gallium nitride (GaN) field effect transistor (FET) matrix converter for variable frequency drive applications. To limit the high dv/dt caused by the fast switching operation of GaN devices, a dv/dt filter is employed. With the dv/dt filter, the input terminal voltage can meet the standards suggested by National Electrical Manufacturers Association. On the other hand, when a GaN FET matrix converter and an electric motor are connected by a long cable, the parasitic impedance of the cable varies. This impedance mismatch results in voltage reflection (VR), and this VR causes a large surge voltage with severe ringing at the motor input terminal. Even in this case, the dv/dt filter effectively restricts the dv/dt of the voltage applied to the electric motor. Frequency response results are obtained through the transfer functions of the filter according to the applied position. Experiments are carried out using a 220 V/60 Hz induction motor and a GaN FET-based matrix converter prototype. The dv/dt filter performance with two positions and cable lengths of 5 m and 25 m is evaluated by comparing the obtained experimental results with the frequency response.