99%—Efficient, interleaved bidirectional DC‐DC converter with new interleaved PWM method of parallel‐connected Mosfets

Abstract

AbstractA new high efficiency interleaved pulse‐width modulation (HE‐IPWM) method using parallel‐connected Mosfets is presented. The IPWM is evaluated using a bidirectional DC‐DC converter for charging and discharging a battery. The results show an excellent DC voltage gain without an extremely large duty cycle. Compared with conventional pulse‐width modulation (CPWM), the IPWM reduces by half the ripple of the battery current. The current ripple of IPWM is four times higher of the switching frequency, while CPWM is two times higher. The proposed interleaved strategy also double the inductor current ripple frequency, whereas in general, is equal to the switching frequency. As a result, the use of the IPWM reduces the weight and size of inductor design. Furthermore, IPWM provides the best battery current ripple at the duty cycle close to 25%. The operating stage, mathematical analyses, and design guidelines of the two proposed modulations are explained in detail. The IPWM experimental results of a 250‐W prototype confirmed the circuit performance. The maximum efficiency of 98.9% is obtained at 250 W for boost mode and 99% for buck mode.