A Bi-Directional Buck/Boost Voltage Balancer for DC Distribution System

A bi-directional Buck/Boost voltage balancer required in DC distribution system is proposed in this paper. Compared with the existing voltage balancer, the proposed balancer is unique in adding a bi-directional Buck/Boost converter, so that it cannot only balance the positive and negative rail voltages of the load side, but also regulate the total load voltage for fluctuating supply voltage. Theoretical analysis is performed to establish the model of this bidirectional Buck/Boost voltage balancer. For meeting the characteristic of the proposed voltage balancer, based on the complementary PWM method the control strategy has been proposed and analyzed. And the simulations have been carried out to verify the validity of the circuit topology.