A Novel Hybrid Dynamic Reactive Power Compensator

Abstract

Abstracts-A novel dynamic reactive power compensation circuit topology suitable for low voltage distribution system was proposed. The efficient compensation of unbalanced load could be realized by the structure of three-phase four-leg inverter circuit. The sinusoidal pulse width modulation (SPWM) control of inverter could ensure the low distortion of voltage and current. Besides, by the regulation of the inverter's output voltage, the compensation reactive power could be dynamically regulated and the aim of system's zero reactive power compensation could be realized. Combined with fixed capacitor compensator, small capacity of inverter is required to compensate dynamic reactive power. The novel dynamic static var compensator (SVC) could improve the system's power factor and voltage stability. Finally, simulations are carried on the platform of PSCAD/EMTDC. The results show that the proposed control strategy is feasible and efficient.Index Terms-power quality; static var compensate; power factor; inverter; sinusoidal pulse width modulation;

Digital Predictive Current Control of a Three-Phase Four-Leg Inverter

“…The four-leg converter is very flexible and widely demanded for three-phase four-wire power electronics applications including the following: distributed generation (DG) [1], [2] with grid-connected [3], [4] or stand-alone operation [5] to deliver high quality power supply to the arbitrary consumer loads; shunt active power filters also known as DSTATCOM [6] to compensate non-linear load harmonics, imbalances, and reactive power in order to maintain sinusoidal supply currents; series active power filters also known as dynamic voltage restorers (DVR) [7] to provide voltage support to sensitive loads during voltage sags, swells, and imbalances; unified power quality conditioners (UPQC) [8] to perform DSTATCOM and DVR functions simultaneously; static Var compensators (SVC) [9] to improve the system's power factor and voltage stability; grid power quality enhancement [10]; active front end (AFE) rectifiers [11] to deal with line imbalances and fault-tolerant operation; common-mode active filters [12] for the minimization of common-mode voltage and electromagnetic interference (EMI); electric motor drive applications for electric vehicles [13] such as independent control of two or more motors from an inverter [14], fault tolerant operation of drives [15], and control of two-phase motors [16]; uninterruptible power supplies (UPS) [17] to feed unbalanced loads with less harmonic current distortion; rural electrification schemes; aircraft power supply networks; satellite earth stations; military, medical and telecommunication equipment.…”