Abstract:A new speed measuring system based on speed sensorless principle is presented to solve the problem of high rate of faults in the existing electric vehicle speed measurement system. The main topology of the speed measuring system adopts the DC-AC structure, the instantaneous current and voltage value of the detecting system, the vector control strategy, the equivalent model of permanent magnet synchronous motor is a DC motor, according to the feedback of current and voltage signal using the DSP trigger pulse is generated in the software, control motor driver module SVPWM. Based on the TMS320F28055 control chip of TI company, the control platform of the speed estimation system is built. The simulation results show that the speed estimator can realize the accurate tracking of the estimated speed to the actual speed, and meets the design index in theory. In open-loop conditions, the physical object has also been verified.