A π-type Compensated Ferrite-Free Domino IPT System for DC Circuit Breakers

This article proposes a novel domino inductive power transfer (IPT) system to provide voltage isolation capability for gate drives in medium voltage dc circuit breakers (DCCBs). The property of reasonably steady outputs under various load conditions is achieved by applying the π-type compensation network. The efficiency of a domino IPT system with identical loads is analyzed, including parasitic resistances. There are two main contributions. First, a ferrite-free PCB-based magnetic coupler combing bipolar with unipolar structures is proposed, lowering cost and weight. Second, a parameter selection method is given to meet the requirements of the output voltages of all loads and the system efficiency. Furthermore, a single-input-five-output prototype is implemented. The transfer distance between adjacent transmitter and receiver is 40 mm, and the switching frequency is 1 MHz. When the input dc voltage is 24 V, the induced voltage of each receiver is around 20 V, and the voltage difference is within 3 V. The maximum efficiency can reach 60% at the total power of 15.5 W. Besides, the prototype is exploited to power five gate drivers of a DCCB during a current turn-off test. The total power consumption is 5.6 W, and efficiency reaches 47%.