Abstract: Compared to the constant switching frequency sinusoidal pulse width modulation (CSFSPWM), the variable switching frequency sinusoidal pulse width modulation (VSFSPWM) method can reduce harmonics and losses without adding additional hardware conditions. We proposed an inverse phase sine passive VSFSPWM (Isin-PVSFSPWM) technology to reduce output total harmonic distortion (THD) and improve time domain characteristics. The relationship between output THD and Isin-PVSFSPWM was quantified. The switching loss and current ripple were analyzed under the Isin-PVSFSPWM method by time domain. Then, a 1-kW H-bridge inverter was built. Experimental results show that the Isin-PVSFSPWM method can be adopted to reduce losses and the output of THD within a suitable spread spectrum range. Compared to CSFSPWM, the THD of the inductor current ripple under the Isin-PVSFSPWM method decreases from 26.22% to 23.92%. The THD of the output current decreases from 3.80% to 3.01%. The efficiency of Isin-PVSFSPWM under D(0.4, 1) increases from 93.69% to 94.75%.