Compensated Reference Current Research Articles

A novel approach for reactive power compensation in hybrid wind-battery system using distribution static compensator

This paper proposes a novel algorithmic approach to compensate the reactive power using distribution static compensator (DSTATCOM) for wind energy conversion system (WECS). Three phase bidirectional converter is utilized to exchange real and reactive power in both directions. The plug-in hybrid electric vehicle (PHEV) is enabled to consume during excess power availability. The battery is connected through a separate bidirectional DC-DC converter to adjust the power at the desired range. The compensated reference current is being generated based on the load requirement, wind power generations and state of charge (SOC) status. The proposed algorithmic approach helps to stabilize the grid by injecting accurate compensating current at the point of common coupling (PCC). Thereby, the proposed approach ensures the grid at balanced states under all operating cases. In order to validate the proposed approach, different case studies have been considered and validated through simulation results using PSCAD/EMDTC software.

Performance evaluation of three‐phase, neutral‐point clamped bi‐directional rectifier for supply and load perturbations

In this study, an improved performance three-phase neutral-point clamped bidirectional rectifier with modified control scheme is proposed. The proposed control strategy takes into consideration the amount/degree of deviation of source voltage from desired rated value during supply perturbation and accordingly modifies the reference current template for each phase individually which is termed as compensated reference current. In other words, magnitude, shape and phase of compensated reference current waveform for each phase are different depending on amount of deviation of that phase. A complete mathematical model of rectifier using pulse width modulation technique is developed. The performance of the converter is evaluated in terms of near unity input power factor, low input current total harmonic distortion, reduced ripple factor of the regulated DC output voltage and particularly the neutral-point voltage balance under different load conditions both for rectification and inversion modes of operation. It is shown that the three-level AC to DC converter with the proposed control scheme displays better performance under source voltage perturbations such as voltage sag, swell, unbalance, harmonics, frequency variations as well as phase angle deviations which are regularly encountered in practical environment.

Real-Time Implementation of Type-2 FLC–Based Shunt Active Filter Control Strategies (p–q and Id–Iq) with Different Fuzzy MFs for Power Quality Improvement

Abstract This research article proposes the shunt active filter (SHAF) control strategies (p–q and Id–Iq), which are used to improve the power quality of the electrical network by mitigating the harmonics with the help of Type-2 fuzzy logic controller (Type-2 FLC) different membership functions (MFs). Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the proposed control strategies has been evaluated in terms of harmonic mitigation and DC link voltage regulation under various source conditions. In order to maintain DC link voltage constant and to generate the compensating reference currents, we have developed Type-2 FLC with different fuzzy MFs (trapezoidal, triangular and Gaussian). The SHAF with proposed Type-2 FLC using Gaussian MF is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed real-time results using real-time digital simulator are presented to support the feasibility of proposed control strategies.

Supply perturbation compensated control scheme for three-phase neutral-point clamped bi-directional rectifier

In this paper, an improved performance three-phase neutral-point clamped bidirectional rectifier with modified control scheme is proposed. The proposed control strategy takes into consideration the amount/degree of deviation of source voltage from desired rated value during supply perturbation and accordingly modifies the reference current template for each phase individually which is termed as compensated reference current. In other words, magnitude, shape and phase of compensated reference current waveform for each phase are different depending on amount of deviation of that phase. A complete mathematical model of rectifier using PWM technique is developed. The performance of the converter is evaluated in terms of near unity input power factor, low input current THD, reduced ripple factor of the regulated DC output voltage and particularly the neutral point voltage balance under different load conditions both for rectification and inversion modes of operation. It is shown that the three-level ac to dc converter with proposed control scheme displays better performance under source voltage perturbations such as voltage sag, swell, unbalance, harmonics, frequency variations as well as phase angle deviations which are regularly encountered in practical environment.

Types‐1 and ‐2 fuzzy logic controllers‐based shunt active filter I d – I q control strategy with different fuzzy membership functions for power quality improvement using RTDS hardware

This research paper proposes the shunt active filter (SHAF), which is used to improve the power quality of the electrical network by mitigating the harmonics with the help of Types-1 and -2 fuzzy logic controllers (Types-1 and -2 FLC) using different fuzzy membership functions (MFs). To carry out this analysis, active and reactive current (I d -I q ) control strategy is chosen. Threephase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the proposed control strategy has been evaluated in terms of harmonic mitigation and DC-link voltage regulation under various source conditions. To maintain DC-link voltage constant and to generate the compensating reference currents, the authors have developed Types-1 and -2 FLC with different fuzzy MFs (trapezoidal, triangular and Gaussian). The I d -I q control strategy with proposed Type-2 FLC is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed real-time results using real-time digital simulator are presented to support the feasibility of proposed control strategy.

Performance analysis and real-time implementation of shunt active filter Id-Iq control strategy with type-1 and type-2 FLC triangular M.F

This research article presents a novel approach based on an instantaneous active and reactive current component (id-iq) theory for generating reference currents for shunt active filter (SHAF). Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the proposed control strategy has been evaluated in terms of harmonic mitigation and DC link voltage regulation under various source conditions. In order to maintain DC link voltage constant and to generate the compensating reference currents, we have developed type-1 fuzzy logic controller (T1FLC) and type-2 FLC (T2FLC) triangular M.F. The SHAF with proposed type-1 and type-2 FLCs using triangular M.F is able to eliminate the uncertainty in the system. By using T2FLC triangular M.F, SHAF gains outstanding compensation abilities. The detailed simulation results using MATLAB/SIMULINK software are presented to support the feasibility of proposed control strategy. To validate the proposed approach, the system is also implemented on OPAL-RT (real-time) simulator, and adequate results are reported for its verifications. Copyright © 2012 John Wiley & Sons, Ltd.

Real-Time Implementation of Shunt Active Filter P-Q Control Strategy for Mitigation of Harmonics with Different Fuzzy M.F.s

This research article presents a novel approach based on an instantaneous active and reactive power component (p-q) theory for generating reference currents for shunt active filter (SHAF). Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the SHAF using the p-q control strategy has been evaluated under various source conditions. The performance of the proposed control strategy has been evaluated in terms of harmonic mitigation and DC link voltage regulation. In order to maintain DC link voltage constant and to generate the compensating reference currents, we have developed Fuzzy logic controller with different (Trapezoidal, Triangular and Gaussian) fuzzy M.F.s. The proposed SHAF with different fuzzy M.F.s is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed simulation results using MATLAB/SIMULINK software are presented to support the feasibility of proposed control strategy. To validate the proposed approach, the system is also implemented on a real time digital simulator and adequate results are reported for its verifications.

A Multifunctional Four-Leg Grid-Connected Compensator

There has been a growing demand for using active power filters (APFs) for grid-connected converter systems based on nonconventional energy sources such as solar, wind, and fuel cells. In addition to power quality conditioning, the APF can also be used for bidirectional active power exchange with the three-phase four-wire grid and, therefore, acts as a multifunctional compensator. This paper presents a four-leg shunt multifunctional grid-connected power quality compensator. The compensator reference currents are generated using the instantaneous p-q-r theory. This paper proposes a simple modification to the conventional theory to eliminate the source neutral current from the three-phase four-wire power system. A digital controller is used to implement dead-beat current control. The outputs of the digital current controller are used as reference voltages for a 3-D space vector modulator (3D-SVM). A new approach for pulse width modulation waveform generation in 3D-SVM is proposed. All the intermediate steps are discussed from the viewpoint of implementation on a digital signal processor field-programmable gate array platform. The multifunctional compensator is analyzed, simulated, and tested experimentally for the most practical conditions in the power system, and the results are presented.

Unified shunt compensator algorithm based on generalised instantaneous reactive power theory

The various compensation strategies for shunt compensators using a generalised instantaneous reactive power theory are discussed. A general instantaneous vector expression for compensator current in terms of active and reactive source powers is given. The equivalent general time domain expressions for compensator reference currents are also derived. Detailed simulation results using MATLAB have been presented to validate the proposed reference current algorithm. The algorithm is implemented in real time on a PC. The experimental generation of ideal compensator currents demonstrates its suitability for practical shunt compensators. A prototype model of compensator has been implemented in the laboratory with a voltage source inverter. Simulated and experimental results are presented and compared.