Research On Bidirectional DC-DC Converter For Battery Formation Equipment

Based on the requirements of the research project and development on large-capacity lithium-ion battery equipment, according to characteristics of discharge modules:low-voltage and high-current charge, and considering the size and cost of equipment, a bi-directional DC/DC converter is designed. It enables the DC bus to charge the battery, and the battery's energy can also be fed back to the DC bus.At first, based on a detailed comparative analysis of the Bi-directional DC-DC converter topology, bi-directional half-bridge DC-DC converter topology is chose to be the main topology of the charge and discharge module. And in accordance with the bus voltage, battery current, power and other specific functional requirements, the main circuit parameters are completely designed and verified in the MATLAB/ Simulink environment.Then, according to the battery charge and discharge characteristics, a control scheme of bi-directional half-bridge DC-DC converter is proposed. It makes the PWM control mode as its core, generates pulse with SG3525 controller chip. The function of constant current battery charge and discharge time-constant is achieved with closed loop regulation. In addition, the protection circuit, starting circuit and the other auxiliary circuit are designed.Finally, according to the design results, an engineering prototype is manufactured, the function of battery charge and discharge energy flows in two-way in the converter is achieved. The correction of the circuit topology selection, design parameters and controlling scheme is verified...