Research on Constant Voltage/Current Output of LCC–S Envelope Modulation Wireless Power Transfer System

Abstract

As a technology that makes power transfer more flexible, wireless power transfer (WPT) technology has become a hot research topic in recent years. However, most of the existing studies are based on a DC–DC WPT system. If applied to AC loads, the traditional system usually contains multiple energy conversion stages, which lead to a low transmission efficiency and therefore higher costs. Besides, the necessary large electrolytic capacitors make the system unreliable and bulky. The goal of this study is to design a reliable and efficient WPT system featuring constant current (CC) and constant voltage (CV) output for AC loads. In this work, an inductor–capacitor–capacitor series (LCC–S) enveloped modulation wireless power transfer (EM–WPT) system is proposed. The design of the proposed system is elaborated in this paper, including the working principle of the system’s power converters, the relationship between CC/CV output characteristics and the input current, and the control strategy of CC/CV output based on an AC–AC boost converter. Lastly, an experimental prototype is configured to verify the CC/CV characteristics. The measured overall efficiency of the system reaches 91% and the power factor of input power supply approaches 1.

Keywords

• wireless power transfer (WPT)
• constant current (CC)
• constant voltage (CV)
• inductor–capacitor–capacitor series (LCC–S)
• envelope modulation wireless power transfer (EM-WPT)
• AC–AC boost converter