Study On High-Gain Output Topology Of Inductive Power Transfer System

Wireless power transmission(IPT) technology, referred to as IPT technology, which can realize contactless power transmission by means of high-frequency electromagnetic field. System can transfer power at different medium with high efficiency get rid of the inherent electrical contact, because of the primary side and the secondary side are completely separated. With high flexibility and stability, IPT has become a hot topic in the transmission of electrical energy recently.Since the IPT system primary and secondary side in the state of physical separation and low coupling coefficient, the output voltage gain of IPT system cannot achieve similar as physical transformer turns ratio gain. For analysis of the system gain respect, the traditional IPT systems typically require additional boost circuits to increase the output gain of the system, or optimize magnetic coupling mechanism. Additional auxiliary circuits make the system be more complicated, while the magnetic coupling mechanism optimization can improve the coupling coefficient, but the improvement of the output voltage gain is limited. In order to improve output gain, this paper proposes a high-gain output IPT system based on push-pull circuit by using different control modes of the phase inductance energy storage ways to increase the injection energy of the system, thereby increasing the output gain of the system.The main contents of this paper include the following aspects:(1) Introduced the constitutions and basic principles of IPT system, analyzed the gain of the basic structure IPT systems. Summarized the work principles and the advantages and disadvantages which can achieve gain adjustment method, mastered the structural characteristics of IPT system and proposed a high-gain output circuit implementations based on push-pull IPT system.(2) The working principle of the energy injection push-pull circuit is analyzed in details, and optimized system configuration parameters, the approach to improve system output gain is proposed based on inductance energy storage. Analysis the relationship between the switch on-duty and output gain based on equal pulse width chopping control method, moreover, the system gain and efficiency performance of the different parameters are analyzed in this paper.(3) The entire resonant half-wave intermittent energy injection control method was proposed based on energy injection and the free oscillation mode. By analyzing basic working principle and building the energy model of the system, and analyzing the relationship between the energy injection and oscillation period, this paper gave out the corresponding period ratio relations to achieve high-gain output and voltage control, as well as soft-switching realization.(4) Established the simulation models of improved push-pull IPT circuit by Matlab/Simulink software and simulated the output gain in two different control modes, and build the corresponding experimental platform. The simulation and experimental results verify that the two control methods can achieve high output gain adjustment.