Research On Topology And Control Strategy Of Contactless Coupled Power Conversion System

As a novel power dispatch method,micro-grid can realize the local consumption of renewable energy generation,and assist power leverage for utility grid.In this thesis,two parts are studied for the active and passive load in DC micro-grid.The first part is to investigate contactless power supply for the mobile active load in the DC micro-grid.The second part is to investigate the air-coupled isolated DC transformer for the static load in the DC micro-grid.Contactless power supply is investigated for the mobile active load,which is represented as the battery pack in electric vehicles in DC micro-grid environment.Series resonant structure is implemented to enable the contactless power transfer;the active load matching method based on the boost converter circuit is studied to regulate the contactless power transfer.The resonant frequency tracking and load detection control is designed.To regulate the load power,a small-signal model of the power adjustment unit is built for design the power control system.The time domain model of this system is established in MATLAB/SIMULINK,and the effect of the system load detection function and power regulation control is verified by the simulation.An experimental platform is built and the experiment is carried out in different medium.The results show that the contactless power transfer,the resonant frequency tracking,and the load detection can be achieved.Also the system has a good adapbility to the position offset.The air-coupled isolated DC transformer is designed for the static load in DC micro-grid,which realizes the bidirectional flow of power between the DC grid and stationary load.The system is based on the half-bridge series resonant topology,and due to different load conditions,two working modes and respective equivalent circuit are studied.A small-signal model under the frequency-mode control is derived.A combined frequency-phaseshift control are proposed.Two different modes are simulated in PSIM;the open-loop scan is used to sketch the characteristics of the system;the closed-loop system of the bidirectional system are established in the MATLAB/SIMULINK.The simulation verifies the effectiveness of the bidirectional control system.After all experiments are used to finally verify the validity of the control scheme of the static load air-coupled isolated DC transformer.