Minimizing Input Current of the Rectifier of LCC–LCC Compensated IPT Systems by Switch-Controlled Capacitor for Improving Efficiency

In the inductive power transfer (IPT) system for automatic guided vehicles with a low-voltage and high-current property, the large current stress in the rectifier is one of the reasons for causing the largest power losses. In this article, a power regulation method with the switch-controlled capacitor (SCC) is proposed to lower the input current of the rectifier at the cost of a limited increase of the inverter's current stress. The SCC is applied in the receiver side of the LCC–LCC compensated IPT system, which is controlled to break the resonant tank of the receiver coil for obtaining the ability to adjust the input current of the rectifier. Thus, by achieving unit power factor in the rectifier, the current stress of the rectifier can be minimized while its ac input voltage is boosted. With the adopting of the SCC, the zero-voltage-switching operation is realized on the inverter. Moreover, the parameters and the control strategy of the proposed system with the SCC are designed. Finally, a 700-W prototype is built. Experimental results show that the proposed method maintains a high efficiency under the heavy-load condition (∼91.0%@700 W) and improves the system efficiency by ∼15.8% under the light-load condition (∼80.5%@100 W).