Compared with traditional medium frequency power supply, modular medium frequency static power supply had the advantages of flexible selection, high reliability, good redundancy and easy system maintenance. The rectifier of medium frequency static power supply should achieve unit power factor control while controlling bus voltage stability. For this reason, the dual current loop control strategy was analyzed concretely. The principle of separating positive and negative sequences of voltage and current in dual current loop controller and the concrete realization method of double dqphase locked loop were introduced, i.e., delay signal cancellation (DSC) and quasi proportional resonance (PR). Aiming at the problems of high harmonic content and difficulty in tracking the fundamental wave of the output voltage of the inverter, a multiple quasi PR control strategy was adopted to achieve the stable output of the medium frequency voltage. The simulation and experimental results showed that the dual current loop controller could achieve bus voltage stability and unit power factor control simultaneously. The medium frequency inverter with double closed loop multiple quasi PR control strategy could output stable medium frequency AC voltage.