Structural characteristics of decentralized bypass for modular UPS power system
The distributed bypass structure of parallel modular UPS power supply system is characterized by that each UPS module in parallel operation has its own bypass power supply branch. Parallel modular UPS power supply system does not need a special bypass power supply branch and a dedicated bypass controller. The bypass switch and the corresponding bypass controller are integrated in the UPS module. The bypass strategy is characterized by simple bypass structure, automatic increase of bypass power supply capacity with the increase of the number of parallel modules, no special bypass controller, easy expansion and modular parallel connection, and high reliability. Because each parallel UPS has a bypass power supply branch, the failure of a bypass switch will not cause the whole UPS parallel system to have no bypass power supply branch. Because bypass controllers are distributed in each parallel UPS module, the load detection results of each parallel UPS only affect the power supply state of the unit. The bypass conversion of all modular UPS in parallel state must satisfy certain conditions, so that the power supply state (bypass state, high resistance state, inverse) can be determined after judging the overload of UPS. Variable state) is more complex. The decentralized bypass strategy is more suitable for modular UPS parallel systems.
In view of the advantages of decentralized bypass strategy, considering the standardization of system design, modular UPS requirements and user-friendly expansion of power supply capacity of UPS parallel system, the modular N+X redundant parallel UPS power supply system studied here adopts decentralized bypass control strategy.