Research On Frequency Tracking Mode Contactless Power Transfer Technology

Contactless Power Transfer (CPT) is a new type of non-contact electric power transmissiontechnology. Compared with the traditional power transmission mode, it is more secure, durable andconvenient. Therefore, the non-contact power transmission technology has a good development andapplication prospects. In order to solve the problem of poor transmission efficacy of the system, thistext studies some key technologies of contactless power transmission system, such as the circuitoptimization design, compensation topology selection and loosely coupled transformer structure etcand the frequency tracking control system was added in the system that can improve thetransmission efficacy.At first, the paper analyzed the base work principle of contactless power transmission system,introduced high-frequency inverter circuit and system compensation topology structure, voltagetype full bridge high-frequency inverter and series-primary compensation structure was determined;Loosely coupled transformer are analyzed, and the measurement method of mutual inductance andcoupling coefficient is given and the coupling coefficient can increase8%-36%when theprimary-secondary side coil use the same structure, internal diameter is almost1/2of externaldiameter. Then it analyzes and simulates the effect of resonant frequency, secondary quality factorand coupling coefficient on the system efficiency, the system transmission efficiency can reachmore than80%when the resonant frequency was set between30and100kHz; It also summarizesthe variation law of frequency change with load switch, gets the conclusion of load switching willinfluence the resonant frequency. At last, the main circuit, the primary-secondary compensationcircuit, loosely coupled transformer and its core material was designed. By testing, the experimentalresults show that the output power system can be improved about25%compared with the systemworking in the constant frequency mode.In this paper, the frequency tracking control system was added in this system, improved thetransmission power of the system and laid the foundation for subsequent experiments andapplications.