New type of power converter for common-ground DC bus sharing to increase the energy efficiency in drive systems

This paper proposes a new type of power converter for drive systems to enable the exchange of recuperated energy within an independent DC subgrid having one centralized energy storage element. Many industrial applications that require rapid cyclic starts and stops are subject to significant energy waste at the brake chopper of the DC bus due to over voltage during motor deceleration. The proposed solution allows the brake chopper to be eliminated and the otherwise wasted energy to be stored externally. The solution does not require identical hardware or exact synchronization between the drive rectifiers. Experimental results in industrial robotics show savings of up to 20%.