Step‐charging technique for CC/CV mode battery charging with low‐cost control components in IPT systems

Abstract

In wireless power transfer technology, power control technique is required to realise constant current (CC) and constant voltage (CV) modes for battery charging. CC and CV modes are needed to effectively charge lithium (Li)-ion batteries to ensure long life span and maximum capacity utilisation. The use of additional battery charging circuitry reduces efficiency, increases volume, and increases circuit complexity. The frequency modulation method is a method that can control power without an additional charging circuit, but a high-resolution controller is needed to control the voltage and current for charging the battery by frequency modulation. This study proposes a system that controls current and voltage for CC and CV modes through a step-charging method using a battery hysteresis with a low-cost control system. The in-band communication circuit is analysed and used to link the primary and secondary sides of the inductive power transfer (IPT) coils, which enables effective feedback control without an additional wireless communication module. This method enables high-efficiency charging while minimising the overall size and cost of mobile IPT applications such as power tools. The proposed system shows 90.3% transfer efficiency with a 20.75 V, 4 Ah Li-ion battery at 7 mm distance.

A Switching Hybrid LCC-S Compensation Topology for Constant Current/Voltage EV Wireless Charging

“…When M resonated with C 1 and L , in combination with (6), (12) and (26), following equation can be derived as…”

“…In a wireless power transfer (WPT) system, there are generally two factors that should be considered simultaneously: zero voltage switching (ZVS) operations are required to reduce electromagnetic interference (EMI) and improve the transfer efficiency [11], and CC/CV hybrid charging is required to ensure long life span and maximum capacity utilization of batteries [12]. Currently, three primary schemes are utilized to achieve these factors.…”

Investigation of triple quadrature pad for wireless power transfer system of electric vehicles

“…Inductive power transfer (IPT) systems or wireless power transfer (WPT) systems can transfer power through air gap without any contact and extra cables to charge the battery of EVs. Safety charging as well as being impervious to a dusty environment, humidity and storms are some of the main reasons that make IPT systems an attractive solution to charge batteries in static, dynamic or quasi-dynamic application modes [1][2][3][4][5][6][7]. An IPT system contains two main transmitter and receiver sides, as depicted in Figure 1.…”

Wireless charging system for electric bicycle application

“…The other problem with wireless charging is that the CC/CV charging modes are required to achieve high charging efficiency and lithium-ion pin protection [14,15]. Therefore, a proper charging control strategy is required.…”