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

Abstract

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.

Shunt Active Power Filter: A Review on Phase Synchronization Control Techniques

“…This section discusses about the phase synchronization techniques which have so far been integrated in the control system of SAPF. It includes the two common techniques in the literature namely zero-crossing detection (ZCD) [19,51,52] and phase-locked loop (PLL) [53][54][55], and the more recent techniques such as artificial neural-network (ANN) or adaptive linear neuron (ADALINE) [56][57][58], fundamental component extraction [59,60], and unit vector generation [61][62][63]. In this manuscript, the synchronization techniques are classified according to the intended application of SAPF, i.e., either for single-phase or three-phase power system, as illustrated in Figure 3.…”

Adaptive Linear Neural Network Approach for Three-Phase Four-Wire Active Power Filtering under Non-Ideal Grid and Unbalanced Load Scenarios

“…The overall updating process performed by the W-H weight updating technique is as follows: Figure 2. Control structure of a generalized adaptive linear neuron (ADALINE) module [11,19].…”

“…Hence, to minimize this problem, suitable learning rate γ in the range of zero to one (0 < γ < 1) is added. Anyhow, the best γ value reported for fundamental current estimation is 0.0006 [16,19]. Note that a fully updated i L f und_est will have the following expression.…”

“…Meanwhile, according to the ADALINE-based fundamental voltage extraction algorithm, the synchronization phase is literally a unity representation of the source voltage, obtained by dividing the sinusoidal source voltage with its magnitude (extracted by the ADALINE algorithm) [16]. In this case, if the source voltage is distorted and/or unbalanced, the unified ADALINE (as a whole) will probably fail to work as desired [19]. Fortunately, techniques to deal with distorted and/or unbalanced source voltage scenarios have been developed such as by using adaptive notch filters (ANFs) [20] and highly selective filters (HSF) or self-tuning filters (STFs) [18,19,21].…”

“…In this case, if the source voltage is distorted and/or unbalanced, the unified ADALINE (as a whole) will probably fail to work as desired [19]. Fortunately, techniques to deal with distorted and/or unbalanced source voltage scenarios have been developed such as by using adaptive notch filters (ANFs) [20] and highly selective filters (HSF) or self-tuning filters (STFs) [18,19,21]. For the purpose of generating reference current, STF has been integrated with ADALINE technique (named as STF-based ADALINE) and this innovative technique has been reported to work effectively under various distorted and/or unbalanced source voltage scenarios [19].…”