文档介绍：Electric Power Systems Research 76 (2006) 271–282
Analysis and implementation of three-phase power pensator
under the balanced and unbalanced load conditions
Bor-Ren Lin ∗, Tsung-Yu Yang
Power Electronics Research Laboratory, Department of Electrical Engineering, National Yunlin University of Science and Technology,
Touliu City, Yunlin 640, Taiwan, ROC
Received 14 October 2004; received in revised form 21 January 2005; accepted 6 May 2005
Available online 12 October 2005
Abstract
An active power filter with asymmetric inverter legs are presented to eliminate harmonics, compensate reactive power and draw the balanced
line current from the AC source under balanced and unbalanced load conditions. Three inverter legs are used in the adopted voltage source inverter.
In each leg, four active switches are adopted to achieve three-level pulse-width modulation (PWM). No clamped diode or flying capacitor is used
in the proposed inverter. In the adopted control algorithm, a classical proportional-integral voltage controller and hysteresis current controller are
used to maintain DC-link voltage constant and to track line mands, respectively. A pensator is added in the inner control
loop pensate the neutral point voltage variation due to load variation. Based on the proposed PWM control scheme, a three-level voltage
pattern is generated on the AC terminal of the inverter. The system configuration and mathematical analysis are discussed in the paper. Finally, the
experimental results based on a laboratory scaled down prototype are provided to verify the effectiveness of the control algorithm.
© 2005 Published by Elsevier .
Keywords: Voltage and current controller; Pulse-width modulation; Inverter
1. Introduction reactive power theory [1] or synchronous reference control
scheme [2] were proposed to achieve power factor correction.
The widely use of nonlinear loads, such as diode and thyris- Six active switches with voltage stress of DC-link voltage a