Improved circuit of the switched coupled-inductor cell for dc-dc converters with very large conversion ratio

By replacing the inductor in a basic boost converter by a multiple-coupled-inductor, and adding two diodes and a capacitor, a new converter with a large conversion ratio and low stresses on the switches is obtained. The additional diode helps to circulate the leakage inductance energy to the load in a non-oscillatory manner. The transistor turns on/off with soft-switching. The diodes turn on with zero-voltage switching and turn off with zero-current-switching, their reverse-recovery problem is alleviated. The voltage stress on both the transistor and diodes is less than the output voltage. Computer simulation and experimental results confirmed the theoretical expectations.