Power Factor Control Method Based on Virtual Capacitors for Three-Phase Matrix Rectifiers

Abstract

This paper proposes a novel input power factor control method based on a concept of virtual capacitors to provide unity input power factor for three-phase matrix rectifiers. The proposed algorithm introduces, at the input terminal of the matrix rectifier, an imaginary input capacitor generated by modifying a reference vector of the space vector modulation method. The virtual input capacitor, which is fictitiously built in parallel with an input LC filter, successfully compensates for the leading power factor of the LC filter of the matrix rectifier. Thus, the proposed method yields a unity power factor operation despite the presence of the LC filter of the three-phase matrix rectifier. In addition, under a condition when the unity power factor operation cannot be realized, the proposed algorithm adjusts a virtual capacitance to obtain a maximum achievable power factor operation. Because the proposed technique yields the input power factor control by introducing the virtual capacitor and adjusting a reference space vector, the proposed algorithm can be easily incorporated with conventional space vector modulation algorithms for the three-phase matrix rectifiers. Thus, the proposed method can control input power factor without employing proportionalintegral controllers used in conventional power factor control methods for the matrix rectifiers, leading to simple control structure and straightforward tuning process for power factor control.

Current-Limiting Soft Starting Method for a High-Voltage and High-Power Motor

“…Based on the research findings [28][29][30][31][32] and according to the above current-limiting starting characteristic curve, a device was developed which integrated current-limiting starting, reactive compensation, and harmonic filtering (hereinafter referred to as integrated device). The topological structure of the integrated device is shown in Figure 2.…”

Reduction of DC Current Ripples by Virtual Space Vector Modulation for Three-Phase AC–DC Matrix Converters

“…Basically, it is a single-stage bidirectional current source AC-DC converter, which rectifies the sinusoidal AC signals to the pure DC signals. Different modulation strategies have been applied for the AC-DC MCs, such as the Alesina-Venturini [5], the pulse-width modulation (PWM) [10,11], the model predictive control (MPC) [12][13][14], and the space vector modulation (SVM) [15][16][17][18][19][20][21]. Predictive control strategies for the AC-DC MCs under unbalanced grid voltage were proposed in [12] and [13].…”

“…The optimized modulation strategy to deduce the charging current ripple for vehicle to grid (V2G) applications using the AC-DC MC was presented in [20]. An input power factor control method was studied in [21] based on the concept of the virtual capacitor. A controlled rectifier was implemented in [22] using the AC-AC MC theory.…”

Predictive Control Method Based on Adjacent Vector Confinement Technique for a Three-Phase AC-DC Matrix Converter with High Efficiency

“…Several modulation methods have been successfully adapted to the AC-DC MCs [9]. An AC-DC MC is traditionally controlled by a space vector modulation algorithm [10][11][12][13][14][15][16][17]. Literature [10] presents a digitally controlled power supply for isolated three-phase AC-DC MCs without modulation blocks.…”

“…DC current ripple reduction algorithms are studied in References [15,16]. Application of the virtual capacitor concept to the AC-DC MCs to control the input power factor is presented in Reference [17]. Recent studies have shown the massive potential of model predictive control (MPC) thanks to the advanced development of fast and powerful digital microprocessors and power devices [18,19].…”