An Analysis of a voltage clamped zero-voltage switching two-inductor boost converter with a wide load range

The Zero-Voltage Switching (ZVS) two-inductor boost converter has been previously developed for the dc-dc conversion stage in a photovoltaic (PV) Module Integrated Converter (MIC). In order to apply Maximum Power Point Tracking (MPPT) to the PV module, the resonant dc-dc converter is required to operate with variable input output voltage ratios. It has been established that the variable load operation of the ZVS two-inductor boost converter can be achieved by variable frequency operation, where the three circuit parameters including the load factor, the timing factor and the delay angle are adjusted to maintain the resonant switching transition. However, the ratio of the maximum to the minimum output voltages of the ZVS two-inductor boost converter is limited to 2.3 if the MOSFET voltage rating of 200 V is applied. In order to operate the converter with a wider output voltage range and without the penalty of the high MOSFET voltage stress, mechanisms which are able to control the MOSFET voltage below a certain level are required. This paper studies the variable frequency operation of the ZVS two-inductor boost converter with a simple voltage clamping circuit.