DISTRIBUTED INTERNAL FAULT BYPASS IN A MODULAR UNINTERRUPTIBLE POWER SUPPLY

摘要

A modular uninterruptible power supply is presented having multiple power modules. Each power module contains an internal bypass circuit sized for its particular power module, and preferably to carry two per unit load. The system also includes internal control circuitry for each power module that control transitions between the inverter and bypass modes of operation. Both the high speed communication bus and a high level interrupt line are utilized to minimize the transfer break time between different modes of operation while ensuring that the inverter is never paralleled with the utility line voltage. To further minimize this transfer time, a solid state switching circuit is utilized to provide the initialization between operational modes. To maximize the efficiency during the bypass mode of operation, and electromechanical relay is utilized in coordinated operation with the solid state switching device to provide long-term power requirements during the bypass mode.