Abstract: A method for controlling the power system is presented. The power system is composed of at least one inverter for supplying AC power to a load through a bus, a phase lock system to synchronize all output voltages of the inverters and a current sharing circuit to properly distribute the load current among all inverters. Each inverter is controlled by an unbalanced power to limit the increase of its cross current. Moreover, the information related to DC bus voltage is further applied to control the inverters, whereby the cross current is mitigated and entire power system is operated steadily.

Abstract: A power redundant power system and a method for controlling the power system are presented, wherein the power system is composed of at least one inverter for supplying AC power to a load through a bus, a phase lock system to synchronize all output voltages of the inverters and a current sharing circuit to properly distribute the load current among all inverters. Each inverter is controlled by an unbalanced power to limit the increase of its cross current. Moreover, the information related to DC bus voltage is further applied to control the inverters, whereby the cross current is mitigated and entire power system is operated steadily.

Abstract: A power redundant power system and a method for controlling the power system are presented, wherein the power system is composed of at least one inverter for supplying AC power to a load through a bus, a phase lock system to synchronize all output voltages of the inverters and a current sharing circuit to properly distribute the load current among all inverters. Each inverter is controlled by an unbalanced power to limit the increase of its cross current. Moreover, the information related to DC bus voltage is further applied to control the inverters, whereby the cross current is mitigated and entire power system is operated steadily.

Abstract: A modular AC power supply system with fault bypass and the method of switching output modes is provided. The system architecture allows a plurality of uninterruptible power supply (UPS) modules connected in parallel to share the loads and tripped for fail independently. A virtual control center is automatically installed in one of the UPS modules at system initialization, used for controlling all UPS modules connected over the UPS network. When a disorder is detected in any UPS module, the virtual control center first collects the operation data from other parallel UPS modules through a high speed communication line, and then decides to send a command to the failing module to trip and shutdown, or to send a command to all parallel UPS modules to switch to the bypass mode through a high speed communication line. The system also employs a low priority interrupt with the falling edge of sync clocks to enhance the overall system reliability and the usage of system resources.

Abstract: A power redundant power system and a method for controlling the power system are presented, wherein the power system is composed of at least one inverter for supplying AC power to a load through a bus, a phase lock system to synchronize all output voltages of the inverters and a current sharing circuit to properly distribute the load current among all inverters. Each inverter is controlled by an unbalanced power to limit the increase of its cross current. Moreover, the information related to DC bus voltage is further applied to control the inverters, whereby the cross current is mitigated and entire power system is operated steadily.

Abstract: An uninterruptible power supply (UPS) system and control method thereof is provided. The system contains a plurality of UPS modules connected in parallel, and each module is equipped with full uninterruptible power supply capabilities, and redundant control logic and functional capabilities for self-initiated role detection, master arbitration and parallel processing. The UPS system is self-initialized through a master arbitration process to elect a virtual master among the peers for maintaining inter-unit signaling between parallel UPS modules and controlling the parallel operation. If the virtual master is failed, other UPS modules will initiate the role detection and master arbitration to re-elect a new virtual master. Parallel operation is accomplished without any external controller; the system can be operated with only one UPS module; distribution of adequate resource to each module is properly arranged, thus the risks of system-level single-point failure are much reduced.

Abstract: A modular AC power supply system with fault bypass and the method of switching output modes is provided. The system architecture allows a plurality of uninterruptible power supply (UPS) modules connected in parallel to share the loads and tripped for fail independently. A virtual control center is automatically installed in one of the UPS modules at system initialization, used for controlling all UPS modules connected over the UPS network. When a disorder is detected in any UPS module, the virtual control center first collects the operation data from other parallel UPS modules through a high speed communication line, and then decides to send a command to the failing module to trip and shutdown, or to send a command to all parallel UPS modules to switch to the bypass mode through a high speed communication line. The system also employs a low priority interrupt with the falling edge of sync clocks to enhance the overall system reliability and the usage of system resources.

Abstract: A parallel redundant power system and a method for control the same, wherein the power system is composed by UPS modules with outputs coupled in parallel to supply power to a load through a bus. The control method employs the P−&ohgr; and Q−V slope lines of the droop method to perform phase locking and current sharing. Moreover, the method further utilizes the internal impedance of the UPS in accompaniment with a current shift method to simulate an actual inductor being coupled to the output of the UPS module so as to satisfy the droop method. Therefore, the drawbacks otherwise caused from actual inductors such as the large size and heave weight are eliminated.