一种UPS的无互联线并联控制技术研究

由于模块化电压型逆变器并联控制便于系统扩容和提高系统可靠性,因而逆变器之间或逆变器与公共电网之间组成的并联运行系统正向众多领域(如UPS系统)推广应用. 本文介绍了一种基于频率和电压下垂均流控制的无互联线并联UPS系统.由于采用有功和无功功率作为控制变量,从理论上分析了输出功率与两台UPS之间的输出电压的相位差和幅值差的关系,给出了系统的数字控制方案,在采用TMS320F240控制的两台3KVA的UPS上进行了实验,验证了理论分析.

Parallel operation technique of UPS system by wireless load sharing control

The control strategies about parallel operation system of modularized voltage source SPWM inverters with other inverters or with utility source have been applied in many fields, especially in uninterruptible power supply (UPS). The multi module inverters can flexibly implement expansion of power system capacities. Furthermore, it can be used to build up parallel redundant system in order to improve the reliability of the whole power system. A load sharing control based on the frequency and voltage drop concept for parallel operation of two UPS system with no control interconnection lines is presented in this paper. Firstly, due to the use of active power and reactive power as control variables, the characteristics of output powers according to the amplitude and phase differences between the output voltages of two UPS system are analyzed. Secondly, the digital control algorithm based on the wireless parallel operation is presented. Finally, experiments are presented to verify the theoretical discussion with two 3KVA UPS system employed TMS320F240.