Efficiency‐based design optimisation of a double‐sided LCL compensated wireless power transfer system

Abstract

The double-sided inductor-capacitor-inductor (DS-LCL) compensation topology has been extensively employed in wireless power transfer (WPT) systems owing to its advantages including zero voltage switching operation, constant current output, and no reactive power exchange between the primary and secondary sides. However, in most cases, equality of the primary and secondary coupling inductances is not optimal from the perspective of power transfer efficiency (PTE). This study presents an efficiency-based design optimisation method for DS-LCL compensated WPT system to obtain the highest PTE. The loss sources, as well as their impact on the PTE, are analysed. The analytical equivalent series resistance models of the efficiency-related loss sources are built and validated by practical measurements. The optimisation procedures are given as well. Two 1 A/200 W WPT prototypes are fabricated, tested, and compared, where one of them is designed in terms of the proposed optimisation method, whereas the other is designed in a conventional manner. The power loss on coupling coils of the optimised system is 7.49 W, 21.5% lower than that of the conventional system (9.54 W). The system overall efficiency is increased from 91.65% to 92.67% by utilising the proposed optimisation method.

Integrated control method for constant output voltage and maximum efficiency tracking of bilateral LCL compensation ICPT system

“…The parameter tuning methods of a bilateral LCL compensation ICPT system need to satisfy the following equation [26–29]: The root mean square (RMS) value of the primary coil current I p1 is shown in the following equation: Based on the mutual inductive coupling principle, the RMS value of the secondary inductive voltage U sin is equal to ωMI p1 . The RMS value of the secondary coil current I s1 and the current I s2 can be calculated, respectively,…”

“…The parameter tuning methods of a bilateral LCL compensation ICPT system need to satisfy the following equation [26][27][28][29]:…”

“…In [27], the characteristics of bilateral LCL circuits are fully explored and applied in electric vehicles wireless power transfer. The authors [28, 29] optimised bilateral LCL circuit parameters to improve system efficiency. This paper takes the common bilateral LCL compensation circuit in the ICPT system as an example to verify the effectiveness of the proposed integrated method, which is representative, and it is also applicable to other typical compensation topologies and has a certain universality.…”

“…In particular, the bilateral LCL topology has been studied and applied wildly due to its unique advantages. It can provide an output current independent of load and mutual inductance through reasonable parameter design, minimise the current switched by the inverter and generate a higher power factor at the rated frequency [26][27][28][29]. In [27], the characteristics of bilateral LCL circuits are fully explored and applied in electric vehicles wireless power transfer.…”

Analysis and design of a S/PS compensated IPT system with constant current output

“…It behaves as a CC source when the converter operates at the resonance frequency [20][21][22]. With the CC excitation in the transmitter-side coil, CC output of the receiver side can be obtained by using topologies such as LCL/P [23,24] and LCL/LCL [25][26][27]. It is worth noting that in LCL compensation, the compensation inductance is usually tuned to be equal to the self-inductance of the transmitter coil for generating CC output, which results in extra cost and power loss of the system [28].…”