A decentralized current sharing control strategy for output parallel-connected DC-DC converters with true redundancy

This work presents a decentralized current sharing control technique for a modular power supply composed of n output parallel-connected DC-DC converters. Each converter is connected to the load through individual line resistance. A phase shifted PWM signal, whose phase is proportional to each converters measured output resistance, is used to control switch state, generating a small power flow at switching frequency between connected units. In order to provide proper load sharing, a voltage reference adjustment for the main control loop is done through the weighted sum of measured reactive power at switching frequency and load current controller output. A distributed power system with three buck converters feeding a 75 W Light Emitting Diode (LED) street lighting fixture is tested with simulations to prove the feasibility of the idea.