A comparison of parallel resonant converters operating in lagging power factory mode

Three different parallel resonant converter (PRC) configurations are compared for their performance and analyzed for operation in the discontinuous capacitor voltage mode (DCVM). DCVM operation is shown not to exist in the case of a PRC with the resonating capacitor of the primary side of the high-frequency (HF) transformer. The conditions for DCVM in the case of PRCs with an ideal HF transformer and PRCs with secondary-side resonance differ only in terms of the ratio M/(M+L+L/sub p/), which is equal to 1.0 for a PRC with an ideal HF transformer. The comparison shows that the PRC with the capacitor on the primary side of the nonideal HF transformer is more suited for low-voltage, high-current applications; the PRC with secondary-side resonance is useful for feeding high-voltage, low-current loads; and the PRC with an ideal transformer or with no transformer is more appropriate for low-power, low-output voltage application or where isolation is not required. Experimental results obtained from three phototype units are presented to support the theory.<>