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This paper presents a novel topology for instantaneous reactive power compensation. The topology is derived from the Dynamic-Current or Dyna-C, which is a patented power converter capable of transferring energy for two or multiterminal dc, single- and/or multiphase ac systems. The proposed topology, named dynamic VAr compensator (DVC), has a current source power conversion stage and can provide instantaneous leading or lagging reactive power. The proposed DVC has three individual bridges coupled through a three-winding high-frequency transformer. It has a modular structure that allows it to be series stacked for medium-voltage applications. In addition, the high-frequency Galvanic isolation link provides interphase fault isolation among the three phases. The circuit eliminates the use of electrolytic capacitors for bulk energy storage, which usually lowers life and reliability. Operating principles, theoretical analysis, and design of the proposed topology are described. The converter functionality is validated through simulation as well as experimental results. [ABSTRACT FROM AUTHOR]

Industrial plants are faced with stringent requirements by the utility to maintain a near unity power factor. These plants have traditionally utilized switched capacitor banks as a cost-effective means for power factor correction (PFC). However, if there is a significant level of harmonics present in the current that is disturbing the neighboring loads, then a separate unit for harmonic filtering is required as well. By the time a realistic system is configured, significant cost and complexity are encountered. The concept of a dynamic capacitor (D-CAP) was previously introduced as a means by which to achieve dynamic VAR injection as well as active harmonic filtering in one single integrated unit. The topology consists of taking an existing asset like a PFC capacitor, adding a pair of ac switches and small LC components per phase, and thereby realizing an asset with augmented functionalities. Although the power stage is simple, the underlying control is very challenging. This paper discusses the intricacies of controlling such an architecture and provides keen insights into how one would go about designing a controller. [ABSTRACT FROM AUTHOR]

Industrial plants are faced with stringent requirements enforced by the utility to meet power factor and power quality requirements. These plants, in order to avoid very costly penalties, have traditionally utilized switchable shunt capacitor banks with detuning reactors for power factor correction, along with a separate active harmonic filter in cases where harmonic currents are an issue as well. Alternate solutions such as SVCs and STATCOMs have been considered to be too expensive for use in industrial power conditioning applications. This paper proposes a dynamic capacitor (D-CAP) based on the family of inverter-less active filters that is able to provide a dynamically controllable capacitance with active harmonic filtering integrated into the same unit. This new device is seen to be compact, and is likely to be cost competitive against simple switched shunt capacitors. It can maintain power factor close to unity, offering dynamic capabilities better than switched capacitors or SVCs, possibly lending itself for arc-furnace type of loads. [ABSTRACT FROM PUBLISHER]