Abstract：From the perspective of energy saving and noise reduction of electric vehicle air conditioning system, an analysis has been made of the current harmonic components and switching losses of motor output at different frequencies by different space vector pulse width modulation (SVPWM) algorithms. A combined SVPWM algorithm is designed to meet the requirements of energy saving and noise reduction in complex working conditions of motors by switching the algorithm. A simulation test has been carried out on the sensorless control of PMSM based on the model reference adaptive system in Matlab/Simulink. Combined with the switching loss characteristics of inverters and the requirement of high accuracy for motor torque control at low speed, the switching points of two SVPWM algorithms can be determined in the whole speed range.