Design and Multi-constraint Evaluation of Passive dv/dt Filter for SiC-based Motor Drives

Wide band gap devices represented by silicon carbide (SiC) MOSFET and gallium nitride (GaN) bring lots of advantages to motor drives, such as small volume, high efficiency, low audible noise and so on. However, fast switching process will also cause a very large voltage and current change rate (dv/dt and di/dt), which greatly increases the common mode (CM) electromagnetic interference (EMI) of the system. In the case of long-term transmission, the peak value of the motor terminal voltage will reach twice the bus voltage, which seriously threatens the reliability and life of the motor drive system. In order to resolve this challenge, this paper proposed a simple multi-dimension and multi-constraint filter parameter design strategy. The voltage attenuation, power losses, efficiency, resonant frequency and volume are analyzed at the same time. After that, the filter parameters can be designed accurately. the motor terminal voltage and its dv/dt will be effectively reduced. Moreover, the common mode interference of the system is suppressed, accordingly. The effectiveness of the proposed parameter design method is illustrated by a series of experimental results.