Research On Multi-port Regional Power Router And Its Dc Bus Voltage Control Strategy

Regional power router can provide flexible electrical interfaces for a variety of distributed generation,energy storage,load and distribution networks,and can also rely on information flow to control the size and direction of the power flow between different electrical ports,therefore,it has a broad application space on the customer-side including distributed photovoltaic,energy storage,AC/DC load and AC/DC power distribution network coexisting.The regional power router relies on the DC bus to realize the interconnection of multiple energy terminals.Therefore,the efficient and stable control of the DC bus voltage is essential.However,the diversity of source-network-load-storage brings the complexity of operating conditions,which brings severe challenges to the stable and efficient operation of regional power routers.In order to solve the above problems,based on the analysis of the topology and operating conditions of the regional power router,this paper studies and proposes the corresponding solutions to the problems existing in the DC bus voltage control under the typical operation conditions,so as to realize the efficient and stable operation of the regional power router under different operation conditions.The main work and innovation of this paper are as follows:1)This paper analyzes and summarizes the basic functions and architecture of the regional power router,and puts forward an implementation scheme of the regional power router based on the idea of modularization.The modular power unit can effectively construct a variety of typical ports of the regional power router,and the modular communication control unit based on Ether CAT bus technology can effectively realize the information flow transmission of the regional power router.Based on the above research,the corresponding experimental platform is built,which provides a feasible reference scheme for the design and implementation of regional power router;2)In order to optimize the DC bus voltage control performance of regional power router,the influence mechanism of constant power load and hot swap of distributed energy storage port on DC bus voltage control under grid connection is analyzed,and a grid connection port control strategy based on energy feedback is proposed to effectively eliminate the adverse effect of constant power load on DC bus voltage control.At the same time,the voltage feedforward method is used to effectively suppress the impact of the start-up of distributed energy storage ports and the change of steady-state working point on DC bus voltage control,which effectively improves the DC bus voltage control performance of regional power router under grid-connected conditions;3)In order to optimize the DC bus voltage control performance of the regional power router under islanding,this paper analyzes the mechanism of the influence of transmission power and constant power load on the DC bus voltage control performance,and then proposes a DC port output voltage control strategy based on decoupling.The proposed strategy is verified by theoretical analysis and experiments The decoupling control strategy can effectively solve the problem that the control performance of DC bus voltage deteriorates with the increase of transmission power,and can suppress the adverse effect of constant power load at the same time,so as to effectively improve the DC bus voltage control performance of regional power router under island conditions;4)On the basis of realizing the optimization DC bus voltage control of regional power routers under the two basic operating conditions of grid-connected and islanding,and considering the multi port coordinated control of DC bus voltage under start-up,overload / overcharge,grid connected and islanded switching and other complex conditions,a DC bus voltage coordination control method based on distributed autonomy centralized optimization is proposed.It can effectively realize reliable control of DC bus voltage under various emergency conditions by the distribution autonomy of local controllers at each port.By centralized optimization of central controller,it can effectively coordinate power flow of each port to realize stable control of DC bus voltage under various predictable conditions.The control strategy makes full use of the advantages of communication control unit of regional power router,and effectively realizes the control strategy.Through theoretical analysis and experiments,the proposed control strategy can effectively improve the control performance of DC bus voltage of regional power router under multi working conditions.