Load And Mutual Inductance Identification Method Of ICPTSystem Based On Switching Capacitors

Inductive coupled power transfer(ICPT) technology is a electricity energy wireless transmission technology which is based on electromagnetic induction theory. The direct electrical contact between the power supply equipment and load can be avoided with this technology, which makes it has the advantage of safety, easy maintenance and flexible. This technology has been widely concerned by scholars at home and aboard.With the development of ICPT technology, more and more load can be accessed into the ICPT system, the system need to formulate corresponding control strategy for different size and character of the load. There are few deep researches on load and mutual inductance parameters identification at present. In traditional ICPT load identification methods, the mutual inductance is set to a fixed value or we suppose that the reflecting impedance which comes from the secondary loop is zero, both of them are ideal conditions. However, take the wireless power supply for electrical vehicles as an example, different electrical vehicles have different load characteristics, and different heights and alignment of chassis can cause the air gap between the transmitting winding and the pick-up winding to change, resulting in different mutual inductance. At the same time, the load change reflects the change in the actual power requirement, so the output power of the system should be adjusted to ensure efficient and reliable power transfer. Therefore, there is an urgent need for a load and mutual inductance parameter identification method. It can lay the foundation for realizing the precise control and improving the performance of the system.We use SS-type ICPT system as the research project, study the load and mutual inductance parameters identification. The existing load identification technology are analyzed and studied. Include the method based on reflecting impedance, the method based energy transport model, and the method based on energy injected and energy free oscillation mode. The deficiencies of these already been proposed methods are given in this paper for validation the feasibility and necessity of this research work.The method of load identification based on capacitance switching is proposed with the SS-type circuit topology and foundation theory of load identification. Steady-state mathematical model of capacitance switching are established, the detailed load identification process and calculation formula are given in this paper. The circuits of load identification based on capacitance switching are designed in this paper. Include the methods of ZCS circuit designing and related signal sampling and processing.The Matlab/Simulink load identification model based on capacitance switching is built in this paper; the simulation results have verified the correctness of the proposed method. The experimental platform is built based on the theoretical analysis and simulation results, the change of load and mutual inductance parameters are verified by experiment. The experimental results have shown that the proposed method can identify the load and mutual inductance parameters with high accuracy and reliability, this method can be used to improve the system performance with precise control.