Sinusoidal Source Voltage Research Articles

A Self-Tuning Filter-Based Adaptive Linear Neuron Approach for Operation of Three-Level Inverter-Based Shunt Active Power Filters under Non-Ideal Source Voltage Conditions

This paper presents a self-tuning filter (STF)-based adaptive linear neuron (ADALINE) reference current generation algorithm to enhance the operation of a three-phase three-level neutral-point diode clamped (NPC) inverter-based shunt active power filter (SAPF) under non-ideal (unbalanced and/or distorted) source voltage conditions. SAPF is an effective and versatile mitigation tool for current harmonics. As for its controller, ADALINE-based reference current generation algorithmd have widely been applied and proven to work effectively under balanced and purely sinusoidal source voltage conditions. However, no work has been conducted to study its performance under non-ideal source voltage conditions. In this work, a STF-based fundamental voltage extraction algorithm is integrated with an ADALINE algorithm, serving as synchronizer algorithm to ensure in-phase operation of the generated reference current with the non-ideal source voltage. Hence, it completely eliminates any dependency on conventional synchronizer algorithms such as phase-locked loop (PLL) and zero-crossing detector (ZCD). Additionally, the proposed STF-based ADALINE algorithm implements the modified Widrow-Hoff (W-H) weight updating algorithm for fast generation of reference current. Both simulation and experimental works are performed to verify design concept and effectiveness of the proposed algorithm. Comparative study with another recently reported algorithm is performed to investigate the performance improvement achieved by SAPF while using the proposed algorithm.

Comparison of control strategies for DSTATCOM in three-phase, four-wire distribution system for power quality improvement under various source voltage and load conditions

This paper presents comparison of three different control strategies to generate reference current components for Distribution Static Compensator (DSTATCOM). Reference currents are tracked by a three-phase voltage source converter in a hysteresis band control scheme. These methods are instantaneous reactive power (IRP) theory, symmetrical component (SC) theory and an improved instantaneous active and reactive current component (IARCC) theory. The performance of three methods has been evaluated under various source voltage and load conditions with new IEEE Standard 1459 power definitions. A comparative study of their performance in terms of rms value of source current, Total Harmonic Distortion (THD), supply power factor and compensator ratings is also presented. A three-phase, four-wire distribution system supplying linear as well as non-linear load is considered for simulation study which is carried out using MATLAB/SIMULINK software. Under balanced and sinusoidal source voltage conditions, all three control strategies similar performance while an improved IARCC theory outperforms, particularly, under unbalanced and distorted source voltage conditions.

Control strategies for harmonic mitigation and power factor correction using shunt active filter under various source voltage conditions

This paper gives a new insight into the concept of load compensation using shunt active filter (SAF) under ideal and non-ideal source voltage conditions. A novel approach based on an improved instantaneous active and reactive current component method is proposed. The performance of the proposed control strategy has been compared with instantaneous reactive power theory, symmetrical component theory and dq theory. SAF has been realized by three-phase voltage source converter. Reference currents generated by control strategies has been tracked by a SAF in a hysteresis band control scheme. The performance of the proposed scheme is evaluated in terms of reactive power compensation, reduction in magnitude of source currents, compensator currents, and harmonic compensation as per IEEE-519 standard. To ascertain the viability of the proposed control algorithm, the performance is evaluated under different source voltage conditions with the IEEE Standard-1459 power definitions. Variation in magnitude as well as harmonic content of source voltage has been considered. Under balanced sinusoidal source voltage condition, all control strategies congregate to similar results. Under unbalanced sinusoidal source voltage condition, dq theory and proposed theory have shown similar performance. However, under distorted source voltage conditions, an improved instantaneous active and reactive current component theory presents superior performance. A three-phase, three-wire distribution system supplying non-linear load is considered for simulation study. Simulation results from a complete model of SAF are presented to validate and compare the control strategies.

Present point of view about the instantaneous reactive power theory

The instantaneous reactive power theory has been the most used in nonlinear load compensation with active power filters (APF). Its application to APF control allows constant source power to be obtained after compensation in a simple way. It works optimally with balanced and sinusoidal source voltage, but not so good with unbalanced or non-sinusoidal source voltage. Although the p–q theory obtains constant source power in all the cases, in the second one the source current obtained is not balanced and sinusoidal. On the other hand, some researches argue that it is not a complete power theory because it does not assign a physical meaning to the power terms. Necessary modifications in the original formulation to treat compensation under any condition of voltage supply are discussed. Moreover, here, it is reformulated in phase coordinates, which allows a simpler treatment for analysing the different compensation strategies. On the other hand, from the power point of view, it is proved that the introduction of instantaneous imaginary power makes p–q formulation a formal theory of electric power in three-phase system. Finally, compensation strategies are applied to a practical power system and the results are presented.