Power Control Strategy for Efficiency Optimization in Parallel DC-DC Conveters

A new control method for efficiency optimization in systems composed of parallel converters is presented in this paper. The proposed methodology considers the individual efficiency surfaces for given ratings of power and voltage and determines the optimum operating point for each converter such that the global system efficiency is maximized throughout the entire operating spectrum. Furthermore, a supervisory control strategy is proposed to manage the power-sharing of the converters according to the optimal surfaces provided by the methodology, enabling a performance enhancement for the system by improving its efficiency. Different approaches can be used to implement the active current sharing (ACS) scheme, and in-depth discussions are provided to guide the designer through the tradeoffs to achieve the desired transient and steady-state behavior for the system. Experimental results show that under light load operation, an improvement of 8.5% is achieved in comparison with a conventional technique of equal power-sharing. This points out that the proposed strategy is especially applicable and can significantly improve the performance of systems powered by batteries or renewable sources.