CAN bus based current sharing control of high-power switching converters

A digital current sharing control method leveraging a CAN bus is developed to inhibit the fluctuating current distributions of parallel converters in high-output oxidation power systems. When compared to conventional current sharing strategies, the proposed design significantly reduces circuit complexity without resorting to an analog current sharing bus, and is extremely robust in maintaining system functionality against one or multiple module failures. The digital control design also features anti-interference among high-power switching converters. In addition to detailing the operation principles and mathematical deductions of the state-space average model, the design of a current sharing controller and a current sharing scheme based on a CAN bus are presented to analyze the steady-state operation of parallel converters and dynamic-state operation. Based on these observations, a proof-of-concept prototype was developed that offers a maximum output power of nearly 400 kW with a current sharing error (CSE) below 2.1%. In addition, this system features outstanding anti-interference capability in intense electromagnetic fields.