| Abstract: | In recent years, parallel operation of inverters is employed to increase reliability and capacity in an uninterruptible power supply (UPS) system. A phase error in PWM carrier‐signals of each inverter causes high‐frequency loop current between inverters. Therefore, the PWM carrier‐signal of each inverter should be adjusted in phase. This paper proposes a detection method of phase error in PWM carrier‐signal and its application to synchronization control for parallel‐connected inverters. A simple definite‐integral circuit achieves detection of the carrier phase error from high‐frequency loop current using no signal line between inverters. The detected carrier phase error is applied to synchronize the PWM carrier‐signal through a PI compensator, and then the high‐frequency loop current can be suppressed. Several experimental test results show the validity of the proposed detection method and synchronization control. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 63– 71, 2006; Published online in Wiley InterScience ( http://www.interscience.wiley.com ). DOI 10.1002/eej.20143 |
