Abstract：The traditional ultra high speed permanent magnet synchronous motor（PMSM）driver uses PWM

equivalent sine voltage output，which leads to severe motor heating due to large harmonics，and it cannot be used in situations where the input voltage changes over a large range，such as fuel cells. To reduce the heat generated by the motor and further expand its application scenarios，a new sine wave voltage output inverter based on three-phase DC/DC converter was proposed，a 120 kr/min ultra high speed PMSM was successfully driven. The experimental results show that the output voltage harmonics of the three-phase sine wave voltage output inverter are lower than those of traditional inverters，which reduces the heat generation of the motor under high speed conditions and has practical engineering application value.

      Key words：ultra high frequency sine wave；Buck-Boost chopper circuit；permanent magnet synchronous

motor （PMSM）