The Research On Steady Voltage And Current Technologies Of Capacitively Coupled Contactless Supply

Contactless power transfer (CPT) technology is one of the research focuses in the field of electrical engineering so far. It uses magnetic field, electric field or ultrasound to transfer electrical energy to relative rest or moving electrical equipments in the contactless form. Compared with the traditional power transfer mode, CPT can eliminate contact spark and mechanical friction, and solve the problem of wire through hard. Besides, it also owns the advantages of convenience, safety and flexibility, which make it has a widespread application prospect in the fields of portable electronics, biomedical, energy transportation, underwater, mines and so on.In recent years, Capacitively Coupled Contactless Power Transfer (CCPT) technology has caused extensive research of scholars for its unique advantages, and it has high practical value.The paper focuses on the steady voltage and current technologies of Capacitively Coupled Contactless supply, in order to achieve the stability of the power transfer with the change of the coupling capacitance or the load. During the study, the main work of the paper is as follows:In order to carry out the research work, the paper briefly introduces the general structure of CCPT system, and analyzes the three parts of the high-frequency inverter circuit, electric field coupling mechanism and the compensation circuit in detail, and also summarizes the characteristics of CCPT system.The double class-E inverter is studied to provide high-frequency power to the coupling capacitor. The paper analyzes its specific work modes, deduces the formulas of its component parameters in detail, and analyzes its PWM control circuit and the drive circuit. The high-efficiency of double class-E inverter is verified by using simulation and experiment methods.The steady voltage and steady current output characteristics of CCPT system are studied. Under the fundamental condition, the paper designs the impedance transformation circuits based on resonant principle, so that the valid values of the load voltage and current are approximately invariant with the change of the coupling capacitance or the load. Therefore, the relatively complex frequency tracking technology is avoided.The corresponding simulation models are built by the power electronics simulation software of PSIM, and the steady voltage and steady current output characteristics of CCPT system based on double class-E inverter are studied by the use of PSIM. The actual system is built based on the theoretical analysis and simulation results. The principle and design are validated by means of both simulations and experiments. The results show that, the CCPT system is still able to output steady voltage and steady current with the change of the coupling capacitance or the load, which will enhance the adaptability of the CCPT system circuit to the changes of the coupling capacitance and the load.