Title :
Design and Analysis of Multiloop Controllers With DC Suppression Loop for Paralleled UPS Inverter System
Author :
Guofeng He ; Min Chen ; Wei Yu ; Ning He ; Dehong Xu
Author_Institution :
Inst. of Power Electron., Zhejiang Univ., Hangzhou, China
Abstract :
This paper proposes an improved control strategy to eliminate dc circulating current in the paralleled uninterrupted power supply (UPS) systems. The active and reactive power control has good performance on restricting ac circulating current. However, it is unable to suppress dc circulating current effectively. Based on conventional active and reactive power control for load sharing in paralleled UPS systems, a dc circulating current suppression loop is introduced to each paralleled inverter module, which is used to eliminate the dc component of output voltage in each paralleled inverter module. The dc circulating current control is decoupled since each inverter module only regulates its own dc component. The proper design of multiloop controller parameters for the dc suppression loop ensures excellent steady-state and dynamic performances. The proposed dc circulating current suppression method is verified by experimental results of a paralleled three-phase UPS inverter system.
Keywords :
control system synthesis; electric current control; invertors; reactive power control; uninterruptible power supplies; DC circulating current control; DC circulating current suppression loop; dynamic performance; improved control strategy; load sharing; multiloop controller design; paralleled inverter module; paralleled three phase UPS inverter system; reactive power control; steady-state performance; uninterrupted power supply; Analog-digital conversion; Inverters; Reactive power control; Uninterruptible power systems; Voltage control; DC suppression loop; decoupled control; multiloop controllers; multimodule paralleled inverter system; uninterruptible power supply (UPS);
Journal_Title :
Industrial Electronics, IEEE Transactions on
DOI :
10.1109/TIE.2014.2314059