Wireless Battery Charging Circuit Using Load Estimation Without Wireless Communication

Lee Lee,Choi Choi,Kang Kang,Kim Kim

doi:10.3390/en12234489

Lee Lee, Choi Choi + Show 2 more

Open Access

https://doi.org/10.3390/en12234489

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Abstract

A wireless battery charging circuit is proposed, along with a new load estimation method. The proposed estimation method can predict the load resistance, mutual inductance, output voltage, and output current without any wireless communication between the transmitter and receiver sides. Unlike other estimation methods that sense the high-frequency AC voltage and current of the transmitter coil, the proposed method only requires the DC output value of the peak current detection circuit at the transmitter coil. The proposed wireless power transfer (WPT) circuit uses the estimated parameters, and accurately controls the output current and voltage by adjusting the switching phase difference of the transmitter side. The WPT prototype circuit using a new load estimation method was tested under various coil alignment and load conditions. Finally, the circuit was operated in a constant current and constant voltage modes to charge a 48-V battery pack. These results show that the proposed WPT circuit that uses the new load estimation method is well suited for charging a battery pack.

Highlights

Wireless power transfer (WPT) technologies have been rapidly developed and widely applied to many industrial applications, such as biomedical devices, consumer electronics, manufacturing facilities, and electric vehicles (Evs), where direct contact between power supplies and applications is impossible or inconvenient [1,2,3,4]
Most of the wireless power transfer (WPT) circuits use electromagnetic coupling between coils. These WPT circuits use capacitors to reduce reactive power [5,6,7,8,9,10,11,12,13], and can be largely categorized into four types, depending on whether the capacitors are connected with the transmitter and receiver coils in series and series (S-S), series and parallel (S-P), parallel and parallel (P-P), or parallel and series (P-S) [5,6,7]
Powertransfer transferefficiency efficiencyofofthe theproposed proposedWPT. These results show that the proposed load estimation method is suitable for use in battery charging, These results show that the proposed load estimation method is suitable for use in battery and that the adjustment of φ was crucial to have I follow Iref in constant current (CC) charging mode and to have Vbat charging, and that the adjustment of φ was crucialbat to have Ibat follow Iref in CC charging mode and to follow charging voltage limit (CVL) in constant voltage (CV) charging mode

Summary

Introduction

Wireless power transfer (WPT) technologies have been rapidly developed and widely applied to many industrial applications, such as biomedical devices, consumer electronics, manufacturing facilities, and electric vehicles (Evs), where direct contact between power supplies and applications is impossible or inconvenient [1,2,3,4]. Most of the WPT circuits use electromagnetic coupling between coils. These WPT circuits use capacitors to reduce reactive power [5,6,7,8,9,10,11,12,13], and can be largely categorized into four types, depending on whether the capacitors are connected with the transmitter and receiver coils in series and series (S-S), series and parallel (S-P), parallel and parallel (P-P), or parallel and series (P-S) [5,6,7].

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