Zero Voltage Switching for High Power Three-Phase Inductive Power Transfer With a Dual Active Bridge

Inductive power transfer (IPT) technology used for charging electric vehicles faces challenges in transferring high power because the power capacity and switching losses of high-frequency semiconductor devices are limiting factors. A three-phase system is a common high-power solution and soft switching is crucial for efficiency-oriented applications with high switching frequencies. In addition, dual active bridge (DAB) topology is a suitable topology for soft switching and has advantages in controllability and high efficiency. Therefore, to obtain higher power and efficiency, this paper studies the zero voltage switching (ZVS) of a three-phase inductive power transfer system with a dual active bridge. The three-phase IPT system with a DAB is different from both the normal three-phase DAB converter and the single-phase IPT system with a DAB, so their ZVS conditions and ranges are also different and need to be studied. This paper investigates the conditions and operating range for realizing zero voltage switching of the three-phase IPT system with a DAB. Based on this, the efficiency of the system is improved by changing the load angle between the primary and secondary sides. Finally, a 60 kW three-phase IPT system with a DAB is built, and the experimental verification of the study is conducted.