A simple frequency-independent method for calculating the reactive and harmonic current in a nonlinear load
TL;DR: A simple and effective method for calculating the reference current necessary to feed a shunt active power filter to compensate the power factor and harmonic currents generated by a nonlinear load is described.
Abstract: A basic criterion that determines the behavior of an active power filter is the method of calculating the reference current. There are many ways of generating this reference, but the methods are generally complex and hard to tune. This paper describes a simple and effective method for calculating the reference current necessary to feed a shunt active power filter to compensate the power factor and harmonic currents generated by a nonlinear load. Simulations and experimental results are presented, showing that the proposed circuit may operate at frequencies ranging from 40 to 65 Hz without adjustment.
Citations
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08 Oct 2000
TL;DR: In this paper, the authors proposed several concepts of integrators for sinusoidal signals, including parallel and series associations of the basic PI units using the stationary frame generalized integrators, for current control of active power filters.
Abstract: The paper proposes several concepts of integrators for sinusoidal signals. Parallel and series associations of the basic PI units using the stationary frame generalized integrators are used for current control of active power filters. Zero steady state error for the concerned current harmonics are realized, with reduced computation, under unbalanced utility or load conditions. Designing of the PI constants, digital realization of the generalized integrators, as well as compensation of the computation delay etc. are studied. Extensive test results from a 10 kW active power filter prototype are demonstrated.
838 citations
TL;DR: This new control method aims to compensate harmonics and first harmonic unbalance and is compared with the instantaneous active and reactive power p-q method under various mains voltage conditions and for different harmonic injection high-pass filters.
Abstract: A shunt active filter based on the instantaneous active and reactive current component i/sub d/-i/sub q/ method is proposed. This new control method aims to compensate harmonics and first harmonic unbalance. To evaluate its relative performance, it is compared with the instantaneous active and reactive power p-q method under various mains voltage conditions and for different harmonic injection high-pass filters. Both methods are completely frequency-independent, however under distorted mains voltages the proposed method presents a better harmonic compensation performance. The system synthesis and implementation are performed. Simulation and experimental results are presented.
406 citations
Cites methods from "A simple frequency-independent meth..."
...A large number of AF’s are implemented with a PLL [ 5 ], [9], so using the - control method many synchronization problems are avoided and a truly frequency-independent filter is achieved....
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23 Feb 1997
TL;DR: In this article, the authors developed a control technique for operating two or more single phase inverter modules in parallel with no auxiliary interconnections, using frequency, fundamental voltage, and harmonic voltage droop to allow independent inverters to share the load in proportion to their capacities.
Abstract: To provide reliable power under scheduled and unscheduled outages requires an uninterruptible power supply (UPS) which can be easily expanded to meet the needs of a growing demand. A system suck as this should also be fault tolerant and include the capability for redundancy. These goals can be met by paralleling together smaller inverters if a control scheme can be designed to allow them to operate independently yet still share the load. We have developed a control technique for operating two or more single phase inverter modules in parallel with no auxiliary interconnections. This technique uses frequency, fundamental voltage, and harmonic voltage droop to allow independent inverters to share the load in proportion to their capacities. Simulation results are provided to prove the concept.
332 citations
TL;DR: It is shown that a supercapacitor can serve as both an active and a reactive energy storage and can buffer the periodical low-frequency ripple in the requested power.
Abstract: This paper proposes a line-interactive fuel-cell-powered uninterruptible-power-supply system. A three-port bidirectional converter connects a fuel cell and a supercapacitor to a grid-interfacing inverter. The system can operate in both stand-alone and grid-connected modes. Moreover, an active filtering function is integrated into the system. It is shown that a supercapacitor can serve as both an active and a reactive energy storage and can buffer the periodical low-frequency ripple in the requested power. For connecting the system to the utility grid, a high-performance single-phase phase-locked loop that incorporates an orthogonal filter is presented. Resonant controllers for both the voltage and current regulations eliminate steady-state error and implement selective harmonic compensation. Simulation and experimental results are provided to show the feasibility of the proposed system and the effectiveness of the control methods.
230 citations
Cites background from "A simple frequency-independent meth..."
...5 employs a feedback loop and an integral-gain block to accurately calculate the in-phase current ip(t) [20]....
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04 Mar 2005
TL;DR: In this paper, the available control techniques are described and contrasted in a structured way to identify their performance strengths and the key difference between control methods is the way in which current distortion is treated in the presence of distorted grid voltage.
Abstract: There have been many variants of the active power filter proposed and these variations cover both the circuit topology and the control system employed. Some of the control variants reflect different control objectives but there are still many variants within similar objectives. The available control techniques are described and contrasted in a structured way to identify their performance strengths. Objectives are classified by the supply current components to be corrected and by the response required to distorted grid voltage. The various signal transformations are described in terms of their impact on the distortion identification problem. Time-domain, frequency-domain, instantaneous power and impedance synthesis methods are examined. Additional control functions such as DC-bus voltage and current reference following are also discussed. It is found that a key difference between control methods is the way in which current distortion is treated in the presence of distorted grid voltage.
213 citations
References
More filters
TL;DR: In this paper, a new instantaneous reactive power compensator comprising switching devices is proposed, which requires practically no energy storage components, and is based on the instantaneous value concept for arbitrary voltage and current waveforms.
Abstract: The conventional reactive power in single-phase or three- phase circuits has been defined on the basis of the average value concept for sinusoidal voltage and current waveforms in steady states. The instantaneous reactive power in three-phase circuits is defined on the basis of the instantaneous value concept for arbitrary voltage and current waveforms, including transient states. A new instantaneous reactive power compensator comprising switching devices is proposed which requires practically no energy storage components.
3,331 citations
TL;DR: In this article, an active power filter with quadruple voltage-source PWM converters was developed, of which the power circuit consists of quadruple-VRS converters.
Abstract: The control strategy of active power filters using switching devices is proposed on the basis of the instantaneous reactive power theory. This aims at excellent compensation characteristics in transient states as well as steady states. The active power filter is developed, of which the power circuit consists of quadruple voltage-source PWM converters. As the result, interesting compensation characteristics were verified experimentally which could not be obtained by the active power filter based on the conventional reactive power theory.
722 citations
TL;DR: Active power line conditioning (APLC) as mentioned in this paper is a line conditioning technique that can potentially correct network distortion caused by power electronic loads by injecting equal-but-opposite distortion at carefully selected points in a network.
Abstract: Active power-line conditioning (APLC) is a concept that can potentially correct network distortion caused by power electronic loads by injecting equal-but-opposite distortion at carefully selected points in a network. Results are presented of an extensive literary survey on the subject of APLCs. Thirty-seven key publications are identified and reviewed. Existing and proposed line-conditioning methodologies are compared, and a list of the advantages and limitations of each is presented. >
573 citations
TL;DR: In this paper, a new definition of instantaneous reactive power is presented, which includes both the conventional instantaneous reactive powers and the instantaneous power of a zero-phase component, and a simple control algorithm for the active filter derived from the new definition is described.
Abstract: A new definition of instantaneous reactive power is presented. This definition has a clear physical meaning that includes both the conventional instantaneous reactive power and the instantaneous power of a zero-phase component. A simple control algorithm for the active filter derived from the new definition is described. Simulations verified the control algorithm. >
231 citations
07 Oct 1990
TL;DR: A pulse-width-modulation (PWM) scheme that uses the converter switching frequency to minimize unwanted load current harmonics is described, which results in the reduction of the number of switch communications per cycle.
Abstract: A pulse-width-modulation (PWM) scheme that uses the converter switching frequency to minimize unwanted load current harmonics is described. This results in the reduction of the number of switch communications per cycle. The method is suitable for high-performance variable-speed AC-motor drives that require high-output switching frequencies for near-silent operation. It is also applicable, without change, to voltage or current-source inverters and to two and four-quadrant three-phase PWM rectifiers. Key predicted results have been verified experimentally on a 5 kVA inverter breadboard. >
44 citations