Optimized load sharing control by means of thermal reliability management

As the demand for reliable power systems comprised of parallel-connected converter units continue to increase the need for optimized load sharing techniques rises accordingly. This fact is emphasized by a power system minimization trend that tends to shrink the available PCB area set aside for the power system. These contradictive trends feed the research in topics such as advanced thermal management and dynamic thermal management. Implementation of the latter topic usually requires the use of complicated controllers that continuously monitors the thermal working environment and key components within the system. If the thermal stress exceeds preset limits the controller react according to a predetermined sequence to minimize the damaging effects of excessive thermal stress. This paper combines the dynamic thermal management with the load sharing. It is hereby effectively ensured that the parts count is kept to a minimum while providing a dynamic optimization of parameters such as average and absolute system temperatures as well as overall system reliability. The latter aspect is achieved by redistributing the current throughput of each converter, which in turn results in equal thermal conditions as opposed to well-known and widely used current sharing technique´s intent to establish equal currents.