Battery Charger Utilizing Coupled Inductor Based High Gain Bidirectional DC-DC Converter: Analysis, Design, and Implementation

The bidirectional dc-dc converter with high voltage gain and high efficiency plays an important role in the designing of battery charging systems. In this paper, design and development of a battery charging system utilizing coupled inductor based high gain dc-dc converter is presented. The converter uses a clamp capacitor network to recover the leakage energy of a coupled inductor. The converter has inherent soft-switching capability during turn ON, which ensures high efficiency at high switching frequency. Design equations to derive value of different passive components are given and a step-wise exclusive design to construct coupled inductor is presented. A 50 kHz, 500 W laboratory prototype has been designed, which can increase the voltage with 10 gain (boost operation) in one direction and can reduce the voltage at (1/10) gain (buck operation) in other direction. The CCCV battery charging algorithm is implemented using generic ARM Cortex-M4 microcontroller. Extensive experiments have been performed and the experimental results are presented in buck, boost, and battery charging operations.