In the insulation test of inverter-fed motor, the repetitive pulse square wave voltage can not fully simulate the PWM voltage output from the inverter reflects the insulation failure mechanism of the inverter-fed motor, and the use of different power sources in the same experiment affects the consistency of the experimental data. In this paper, a direct-output PWM voltage generator is designed, which can not only output the SPWM and SVPWM voltage of analog converter for insulation test, but also output the repetitive pulse square wave voltage to carry out contrast experiment. Firstly, a pulse signal generator based on FPGA is designed to generate the SPWM and SVPWM trigger pulse with adjustable fundamental frequency and switching frequency, repetitive square wave trigger pulse with adjustable frequency and duty ratio also can be generated. Then, a chopper based on solid-state push-pull switch is designed to output bipolar high voltage pulse under the trigger of pulse signal. Finally, the experiment of insulation partial discharge of inverter-fed Motor under SPWM voltage is carried out with the pulse voltage generator, which proves the reliability and practicability of the system.