The Influence of Switching Frequency and Bus Voltage on Loss Performance of Electric Motor Drive System

Electric vehicles are gradually replacing fuel-powered vehicles. The electric motor drive system is mainly composed of traction motor, inverter and control unit, which is the core of electric vehicles. However, due to the energy density of lithium battery, electric vehicle is very sensitive to cruising mileage, so efficiency has become an important performance index. Therefore, it is imperative to study the loss performance of the electric motor drive system. The system loss mainly includes motor loss and inverter loss. In this paper, an interior permanent magnet synchronous motor (IPMSM) with 8 poles and 48 slots is taken as an example to build a simulation model in ANSYS Twin Builder, and the influence of switching frequency and bus voltage on loss performance of electric motor drive system are studied under NEDC driving conditions. Simulation results show that the selection of switching frequency needs to be combined with the actual driving conditions and weighed between inverter loss and motor loss; When the ampere turns is certain, increasing the bus voltage can reduce the inverter loss, so as to reduce the total loss of the electric motor drive system.