Abstract: A high-power high-frequency power supply was designed for test requirements of some special

electrical equipment. In the power supply，cascaded H-bridge was adopted to form five-level topology structure，the integrated modulation method was adopted，including bipolar PWM modulation，carrier phase-shifted SPWM

modulation and variable carrier frequency PWM modulation，so as to avoid the disadvantages of high harmonic

output when synchronous modulation at low frequency and low frequency output precision when asynchronous

modulation unable to take into account both high frequency and low frequency，make the power supply have good harmonic characteristics，the output precision of the power supply in the full frequency output range was met. A simple and reliable engineering application method was designed to solve the potential problem of DC voltage imbalance in H-bridge cascade topology.The high-frequency power supply designed has been applied in the field to simulate the linear generator，which prove the feasibility of the design scheme.

      Key words: high-frequency power supply；bipolar PWM modulation；carrier phase-shifted（CPS） SPWM

modulation；variable carrier frequency PWM modulation；DC voltage balance