Analysis of efficiency improvement in wireless power transfer system

Abstract

Recently, efficiency improvement of wireless power transfer (WPT) systems has been the focus of research. Conventional methods of DC-DC converters are employed for load modulation to achieve high efficiency over large variations in mutual inductance and load. However, these additional circuits degrade the performance due to their inherent losses. To address this problem, this study presents a dual-side phase shift control method for load modulation and voltage regulation in a compact WPT system. The key features of the proposed work are: attaining load modulation and voltage regulation with reduced size of the system; elimination of communication between active bridges and simple control logic. Mathematical expression of equivalent resistance versus the phase shift angles (PSAs) is deduced and the optimal PSAs for maximum efficiency are presented. Utilisation of local control, stability analysis and fault detection method are included. MATLAB/Simulink simulation and experimental results are carried out to validate the proposed method.

A Novel Single-switch Phase Controlled Wireless Power Transfer System

“…Active rectifiers with two or four switches can realize PC [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], whereas previous single-switch rectifiers can only adopt duty ratio control [29][30][31][32][33][34][35][36]. Although duty ratio control is easier to implement, it can cause resonant current oscillations when the power transfer path is chopped.…”

“…According to Fourier series and fundamental harmonic analysis [23][24][25], the root-mean-square value of v s (V s ) can be denoted as:…”

“…Active rectifiers are initially put forward to reduce the conduction losses of the diode rectifier and transfer the power bi-directionally [12][13][14][15][16][17][18][19]. Recently, Phase Control (PC) method is introduced to regulate resonant currents [20][21][22][23][24][25], which can further reduce the energy consumed by parasitic resistances.…”

“…Active rectifiers proposed for WPT systems can be classified into three categories: (i) full bridge rectifier with four switches; (ii) semi-bridgeless rectifier with two switches; and (iii) single-switch rectifier. Full active bridge rectifiers are used in various applications [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Four Metal-Oxide- 2…”

An LCC-P Compensated Wireless Power Transfer System with a Constant Current Output and Reduced Receiver Size

“…Wireless Power Transfer (WPT) technology is growing in popularity in recent years due to its non-physical connection between the source and the load [1][2][3], and it has been widely used in diverse scenarios, such as toothbrushes, cell phones [4], electrical vehicles [5], and autonomous underwater vehicles (AUVs) [6][7][8]. Energy is a major factor restricting the long-term continuous operation of the AUV in the ocean.…”