The VSC parallel structure and control technology for the centralized V2G system

According to the centralized V2G high-power converter environment, this paper reveals the mechanism of the uneven flow and circumfluence production with the VSC modules in parallel operation, then proposes a parallel structure and control method of a voltage-source PWM converter (VSC). With the double closed-loop control mode which consists of outer voltage loop and inner current loop under the dq coordinate system, the outer unified voltage regulator of the VSC parallel module is independent to form a common unified voltage regulator. The control method of the VSC parallel module is simplified to a single closed-loop current control, achieving current sharing control among the parallel modules. The method solves the consistency problem of parallel VSC modules energy flows and avoids the generation of circulation among modules. With power expansion of the centralized V2G system, this method structures system power capacity flexibly and improves the system reliability and redundancy. Simulation and experimental results verify the effectiveness and feasibility of this method.