Digital signal processor implementation and performance evaluation of split capacitor, four-leg and three H-bridge-based three-phase four-wire shunt active filters
ABSTRACT In this paper a comprehensive study on the three-phase four-wire (3P4W) shunt active power filter (APF) is carried out on the basis of three system configurations. These three two-level voltage source inverter topologies are compared for 3P4W shunt APF, namely, split capacitor (2C), four-leg (4L) and three single-phase H-bridges (3HB). The performance of all three topologies, under an unbalanced non-linear load condition, is evaluated with a detailed digital signal processor (DSP)-based experimental investigation. The steady-state as well as dynamic performance of APF is studied to compensate for current harmonics, reactive power, current unbalance and neutral current. The advantages and limitations offered by each of the topologies are also discussed in brief.
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ABSTRACT: This paper presents an alternative three-phase four-wire converter for active power filter applications. The topology of this converter consists of four switch-legs, and it uses a "split-capacitor" in the DC-bus. In this converter, three legs are destined to control the injected currents in utility lines, while the fourth leg assures a balanced voltage sharing in the DC-bus capacitors. This converter solves the problem of DC-bus voltage imbalance in the three-leg split-capacitor converter. Moreover, this topology allows each leg to be controlled independently, so injected current control is simpler than in the four-leg full-bridge conventional converter, which utilizes a single capacitor on the DC-bus side. In this sense, a simple constant-frequency current control technique is proposed. In this paper, an analytical study and a verification by simulation are conducted.IECON 02 [Industrial Electronics Society, IEEE 2002 28th Annual Conference of the]; 12/2002