A New Method of Integration Control With Instantaneous Current Monitoring for Class D Series-Resonant Converter

In this paper, the application of the integration control method for class D transistor voltage source series-resonant converters used as dc/dc and dc/ac converters is presented. First, the integration control of the signal as a combination of the resonant frequency and its subharmonics (subharmonic integration control) is discussed. Second, the modulation density of the pulses shorting the bridge diagonal for one current half wave (semi wave integral pulse density modulation) is explained. A detailed control circuit operation, referred to as the four basic algorithms of the resonant current control, is given. The method for the calculation of the value and sequence of the current increments for a dc/dc converter is presented. The results of computer simulations and laboratory experiments demonstrate that the proposed methods allow controlling the converter output quantities fulfilling soft switching conditions (zero-current switching) and provide higher efficiency in comparison to other known methods