Three‐coil structure‐based WPT system design for electric bike CC and CV charging without communication

Abstract

In comparison with the traditional plug-in charging systems for the electric bike (EB), wireless power transfer (WPT) systems have superior advantages of convenience and safety. Combining the application requirement range of the EB, this study proposes a three-coil structure-based WPT system in order to achieve ideal and reliable constant current (CC) output and constant voltage (CV) output without the need for a sophisticated control strategy and the real-time communication links between the transmitter and receiver sides. Two ac switches are utilised at the transmitter side to implement the change of charging mode from CC to CV. By correctly selecting the parameters of compensation components, the required loadindependent CC and CV characteristics with zero phase angle in the CC and CV modes can be achieved. Besides this, a load identification method based on the active power calculation used to estimate the equivalent resistance of the battery in the whole charging process, is utilised to judge the switching point from CC to CV mode. Finally, the feasibility of the method is verified through the construction of a laboratory platform with a 3.3 A charging current and a 57 V charging voltage.

Design and analysis of decoupled tetra‐polar ring‐coils for wireless power transfer in rotary mechanism applications

“…In this experiment, two external series LC resonant circuit is connected up to the primary side loop to reduce k A and k B values of the coupler and suppress the harmonic component as shown in Fig. 14 When the coils on the same side are decoupled, the seriescompensated IPT prototype presents constant current output characteristics with the load variation, which is similar to the single-input and single-output IPT systems [19]. In Fig.…”

“…When the coils on the same side are decoupled, the series‐compensated IPT prototype presents constant current output characteristics with the load variation, which is similar to the single‐input and single‐output IPT systems [19]. In Fig.…”

Method for detecting vertical offset of coupling coil using signal coil based on magnetic coupling resonance wireless power transfer system

“…To realize the parameter above, once the system is setup, one can get a set of data in Fig. 13, and then fit the plot using equation (6), and program the data into the MCU control chip. Based on the analysis and results above, it can be seen that fixing the secondary side power coil open loop, when the primary side coil current is known, the vertical offset of the secondary side power coil can be obtained by the magnitude of the induced voltage on the primary side signal coil.…”

“…Wireless power transfer (WPT) technology has been widely applied for the advantage of convenience and safety compared with cable transfer [1][2][3]. Recently, in the field of consumer electronics, the demand of wireless charging increased dramatically [4][5][6]. To realize high performance power transmission, the communication is indispensable.…”

Design and Implementation of a Cost-Effective Wireless Charger for an Electric Bicycle

“…As the secondary coil is connected to the EV battery, this component can be charged. More complex structures have been proposed with three [6]- [8] or four coils [9]. The power transfer is clearly affected by the relative position or misalignment between the primary and the secondary coils.…”