In order to improve the energy efficiency of new energy vehicles, reducing the inverter loss in the motor electronic control system is a very important part. In this paper, the finite element FEA analysis method is used to build a simulation circuit using MATLAB/Simscape platform. The circuit structure includes bus DC power supply part, permanent magnet synchronous motor control circuit part, three-phase two-level inverter circuit part, permanent magnet synchronous motor module and mechanical transmission system part. The control stratagem of MTPA (Maximum Torque Per Ampere) calculates the corresponding target operating current values of Id and Iq based on different desired torques. The PWM generator is responsible for converting the target voltage, obtaining six PWM waves to control the switching devices in the inverter circuit, and then output the corresponding three-phase AC voltage at the output end. The loss of inverter power components is measured by changing different motor operating points, switching PWM control strategy and changing switching frequency. The simulation results show that the DPWM2 algorithm has less loss for the inverter in the experimental model under the condition of fixed speed and load.