Temperature Integrated Load Sharing of Paralleled Modules

Paralleling power modules is designed to share system loads (stresses) equally to improve system reliability. Due to variations in the parameters in the power converter system, temperature mismatches may occur. These mismatches may lead to unequal life expectancy of individual converters in the total system. It is believed that equalizing the operating temperature of the semiconductor devices may improve total system reliability. In this paper a new thermal-based load-sharing scheme for parallel converters is proposed. In this scheme, the load current is redistributed among parallel converters based on the temperature of the converters. The main goal is to minimize the relative temperature difference between parallel converters while they are supporting load current. To avoid an additional temperature sharing bus, temperature information is integrated with the current information. This information instead of current alone is used in a structure very similar to average current sharing to control the output current of each converter. In this way the converter with the highest temperature will support the least of the load current. Stability analysis of the closed loop system is presented through small signal modelling the parallel converters. Simulation and experimental results presented confirm the performance of the proposed method