Super Capacitor Constant Current Charger

Super capacitor constant current charger is a kind of control device which can convert the AC voltage to constant current.Through the study of the constant current charger, a single stage charger which combines the PFC circuit and the DC/DC converter was proposed in this thesis. The controller has three parts:a main circuit, a feedback circuit and a control circuit. The function of the main circuit is EMI filtering, rectifying and flyback conversion; The output signal of voltage and current is sampled by the feedback circuit which will generate a signal by comparing the output signal with a limit value; By controlling the flyback circuit, the power factor is improved, and the constant current control, overvoltage protection can be achieved.The main circuit, the feedback circuit and the control circuit were simulated by Matlab/Simulink simulation tool in this thesis, and the structure and parameters of the circuit had been determined.The hardware circuit, including the main circuit, the feedback circuit and the control circuit, was designed in this thesis. The main circuit is composed of an EMI filter circuit, a flyback circuit and a high-frequency transformer; The feedback circuit consists of the constant current control circuit and overvoltage protection circuit; The control circuit includes a start circuit, a frequency compensation network, a speed circuit, etc. The hardware circuit experiment and the analysis of the waveforms show that:the designed super capacitor constant current charger can effectively charge the super capacitor.