Highly Efficient Target Power Control for Two-Receiver Wireless Power Transfer Systems

Abstract

Multiple-receiver wireless power transfer (MRWPT) systems have revolutionary potential for use in applications that require transmitting power to multiple devices simultaneously. In most MRWPT systems, impedance matching is adopted to provide maximum efficiency. However, for most MRWPT systems, achieving target power levels and maximal efficiency is difficult because the target output power and maximum efficiency conditions are mostly not satisfied. This study establishes a target power control (TPC) strategy to balance providing target transfer powers and operating under high efficiency. This study is divided into the following points: First, this study derives the optimal mutual inductance to verify that it’s difficult for two-receiver wireless power transfer (WPT) system to achieve both maximum efficiency and power distribution simultaneously; Second, this study illustrates that for impedance matching method the mutual inductances play a more important role than equivalent impedances in increasing the system efficiency, and hence system should give priority in improving the mutual inductance as large as possible; Third, this study proposes a simplified system model which helps to derive the analytic solutions of equivalent impedances; Fourth, this study developed a 100-kHz two-receiver WPT system and establishes a TPC strategy for enabling the system to achieve target output power levels with high efficiency; At last, the proposed system is proved to achieve an efficiency level of more than 90 % and satisfies the target output power levels requirements.

Time-Sharing Control Strategy for Multiple-Receiver Wireless Power Transfer Systems

“…By solving Equations (1) and (9)-(13), the output voltage of the ith load resistance U oi can be derived to give Equation (14).…”

“…Some studies have focused on improving the system efficiency and providing voltage control on MRWPT systems, as discussed in References [10][11][12][13][14][15]. A MRWPT system [10] is proposed for portable devices with simplified receiver design.…”

“…To provide a high efficiency and a transfer target output power in a two-receiver WPT system, a control method based on a simplified math model was developed to meet the demands of different load characteristic [14]. To meet the constant output voltage commands, a load-independent voltage method was analyzed in Sun et al [15].…”

Management of Multiple-Transmitter Multiple-Receiver Wireless Power Transfer Systems Using Improved Current Distribution Control Strategy

“…Some research on single-transmitter multiple-receiver WPT (STMRWPT) systems is presented in [24,[32][33][34][35][36]. A STMRWPT system is developed in [32] for portable devices which are of low-complexity receiver design.…”

“…To increase system efficiency, metamaterials [34] are introduced to multiple receiver WPT system, where the efficiency is increased by about 20%. To provide high efficiency and target output power in a two-receiver WPT system, a control strategy based on simplified math model is proposed [35]. To meet the constant source supply, a load independent output voltage method [36] is proposed to satisfy the demands of different load devices.…”