Inductively Coupled Wireless Power Transfer Technology Based On Active Compensation

With the development of science and technology, wireless power transmission technology has drawn more and more attention. Wireless power transmission technology has three types, include inductively coupled power transfer technology, microwave energy transfer technology and magnetic wireless power transmission. After nearly a few decades of rapid development, these three types of wireless electrical transmission technology have made great progress in theory. Among of them, the first type is the most widely used in engineering applications. Aiming at the problem of large leakage inductance and low transmission efficiency of inductively wireless power transfer system, this puts emphasis on the active compensation. The works related to this thesis are as follows.Firstly, through analyses of resonant principle, an active compensation technology based on capacitor array is proposed. This capacitor is adopted in the receiver to compensate the reactive power. The transmission power and efficiency are also improved. By studying the theory of active compensation, a hardware circuit was designed and developed. According to the experimental result, the voltage and current waveforms are improved.In order to adapt to different applications, this thesis proposes a dynamic compensation based on phase shift. By studying the LC equivalent circuit model of wireless power transfer system, the theory that transmission power can be controlled by phase difference was proved. In the end, a experimental prototype was designed and fabricated, it can test the wireless transmission system, which proves the feasibility of the theory.The main innovation of this thesis is:(1)In this thesis, a method of dynamic control of energy transfer by means of tunable capacitor array and phase shift control is proposed,to solve the problem of the system’s energy transfer ability and the efficiency of the system, which can be solved by the variation of the parameters of the induction wireless transmission system and the uncertainty of the connected load.(2)Soft switching technology is applied in the phase shift control, which is used to complete the energy conversion between the transmitter and the receiver. The experimental results show that the topology can greatly improve the transmission efficiency of the inductive radio transmission.