Balanced Supply Conditions Research Articles

ADALINE-based synchronous detection for enhanced shunt APF performance

Power quality issues caused by current harmonics from nonlinear and unbalanced loads are a growing concern. This paper presents a novel control strategy for four-wire shunt active power filters (SAPF) that surpasses existing conventional methods in mitigating harmonics and power factor correction. The strategy employs an improved synchronous detection method (SDM) enhanced by an adaptive linear neural network (ADALINE) trained using the least mean square (LMS) algorithm. This approach accurately estimates harmonic frequencies, enabling the SAPF to generate precise compensation currents. The effectiveness of the proposed method is validated through MATLAB-Simulink simulations under balanced supply conditions, encompassing diverse load scenarios. These simulation results are compared with those obtained using instantaneous power theory (IPT). They demonstrate the ability of the proposed method to achieve excellent harmonic identification and elimination, to comply with IEEE 519 harmonic limits, to ensure sinusoidal and balanced line currents, and to compensate for reactive power and neutral current. Furthermore, its simple architecture and noise robustness make it a promising solution for enhancing power quality.

A novel Algorithm Adaptive Autarchoglossans Lizard Foraging (AALF) in a shunt active power filter connected to MPPT-based photovoltaic array

Power quality issues often involve harmonics. Harmonics may harm capacitors, overheat equipment, cause motor instability, and increase neutral currents. A shunt filter is used as a harmonic compensation device. The world is moving towards more alternative energy due to its reduced cost. Nevertheless, because conventional energy has downsides of more pollution and higher cost, renewable energy is free of these problems and has higher demands nowadays. There are various conventional control techniques like constant instantaneous power control, Sinusoidal current control, synchronous reference frame and many more. But they lack in areas like less harmonic reduction, accuracy, speed and many more. This paper's main aim is to optimize the common constant instantaneous power control technique using a new adaptive autarchoglossans lizard foraging algorithm (AALF) to control a three-phase active power filter with a solar photovoltaic array installed at its DC-bus. The conventional and optimized control technique will be compared based on the source current THD and voltage THD under balanced supply conditions. The comparison method will be simulation done using MATLAB. In this paper, two key performance aspects will be discussed. They are THD and compensation time.

Unbalance characteristics of fundamental and harmonic currents of three‐phase electric vehicle battery chargers

Three-phase electric vehicle (EV) battery chargers are expected to not impact the unbalance of distribution networks; moreover, using active power factor correction topologies they are expected to behave like resistive loads not affecting the system harmonic distortion. In this study, unexpected unbalance characteristics of fundamental and harmonic currents of three-phase EV battery chargers are analysed by means of experimental tests performed on two EV cars of different technology. In order to quantify unbalance and harmonic distortion, proper comprehensive indices, in part developed in this study with specific reference to currents, are utilised. The unbalanced current absorbed even under ideal voltage balanced supply conditions by one of the two EV tested is shown and quantified constituting a real-life case study of endogenous unbalance. Then, the influence of voltage unbalance supply conditions on fundamental and harmonic currents is evaluated by means of a proposed testing procedure, obtaining case studies of exogenous unbalance. The experimental results obtained for the two EVs should be extended to a larger set of cars; anyway, they show the need, before moving forward to full grid EV connection, for utilities and for designers to improve the current standard certification process and the control performances of three-phase battery chargers.

Design and implementation of ANN-based SAPF approach for current harmonics mitigation in industrial power systems

This article describes with Shunt Active Power Filter (SAPF) for compensation of reactive Power (P), current harmonics. An ADALINE based neural network current estimator can control the SAPF to maintain sinusoidal source currents and unity Power Factor (PF). The three-phase (III-Phase) load currents are sensed and measured by Least Mean Square(LMS) algorithm based on ADALINE, the weights obtained with the help of online calculation, and then these weights are multiplied with the help of unit vector, which gives the fundamental frequency of Load Currents (LC). The DC link voltage (V) of the V Source Converter, maintained at a constant value, and it can work as the SAPF, and various simulation results are presented under the steady-state conditions using the PI controller. The switching action of VSC is performed using Hysteresis Current Control based on pulse width modulation, which makes the source currents should follow the reference source currents. The MATLAB based simulation results and implementation results are obtained to determine the efficacy of the SAPF with ADALINE based neural network control for load compensation. SAPF system meets IEEE Standard 519 recommended harmonic standards for different rated nonlinear loads under balanced supply conditions.

Exploitation of independent stator and rotor geometrical periodicities in electrical machines using the Schur complement

In this paper we present a-priori model reduction technique that enables to take full advantage of the periodicity existing in the stator and rotor geometrical structures of electrical machines in order to reduce the computational time. Firstly, a change of basis is performed by applying two distinct discrete Fourier transformations on the stator and rotor periodic structures independently. Secondly, the Schur complement is introduced in the new spectral basis, to allow a parallel solving of the resulting block-diagonal matrix systems. Moreover, the using of a matrix-free Krylov method based on the conjugate gradient solver has verified an efficient solving of the equation system associated to the stator-rotor interface. Furthermore, in the peculiar case of balanced supply conditions, a model order reduction can be carried out by considering only the dominant discrete Fourier transform components. This model reduction approach is applied on a buried permanent magnet machine and has successfully shown its efficiency under balanced and unbalanced conditions.

Incipient Turn Fault Detection and Condition Monitoring of Induction Machine Using Analytical Wavelet Transform

Diagnosis and monitoring the condition of induction machines and supply system is critical for industries. Incipient fault detection has received reasonable attention in recent years. In this paper, a method based on complex wavelets is proposed for incipient fault detection and condition monitoring. A complex wavelet-support vector machine (SVM) classifier-based method is developed which takes into account four conditions: healthy, turn fault (TF) under balanced supply conditions, voltage imbalance, and interturn fault with voltage imbalance, both occurring at the same time. The performance metrics show the ability of the technique to identify the fault at an early stage and it also provides additional information regarding which of the four conditions is prevailing at a given time. Voltage imbalance and turn fault are often confused. Both affect the performance of the machine and the unbalanced voltage condition considerably reduces the winding insulation life due to overheating. This necessitates the precise identification of the supply condition along with the fault diagnosis. A comparison of the proposed method with standard discrete wavelet transform (DWT) shows its effectiveness in providing reliable information under variable supply-frequency conditions. The proposed technique is also tested in presence of high resistance connections (HRCs), which shows its isolating capability.

Analysis and implementation of a three‐phase power factor correction scheme using modular Cuk rectifier for balanced and unbalanced supply conditions

In this study, the analysis and design of a three-phase AC–DC converter followed by DC–DC Cuk converter modules to achieve unity power factor is presented. Two methods of reference current generation techniques are employed. In the first scheme, reference current is generated using instantaneous symmetrical component theory under balanced supply conditions. In the second scheme, extended synchronous detection methods such as equal current criterion, equal power criterion and equal impedance criterion are used for reference current generation under unbalanced supply conditions. The control strategy uses three hysteresis current controllers for source current shaping and an outer voltage loop with proportional-integral controller for load voltage regulation. To validate the proposed method, a prototype controlled by dSPACE signal processor is set up. Simulation and experimental results indicate that the proposed system offers regulated output voltage for wide load variations and provides power factor close to unity.

Analytical Investigation of an Induction Motor Fed From Four-Switch VSI With a New Space Vector Modulation Strategy

In this paper, an analytical model with a new space-vector modulation strategy for a four-switch (B4), inverter feeding an induction motor drive is derived. The proposed modulation strategy for the B4 operation has the same symmetry as in a classical B6 inverter. The analysis is based on a novel space-vector decomposition technique. The analytical results of the machine are accomplished in an alphabeta complex plane by space vector decomposition and by using a mixed p-z approach. As shown, good agreement exists between the analytically calculated waveforms and the experimentally determined ones. Therefore, the proposed analytical model becomes a very useful method for motor investigation under unbalanced as well as balanced supply conditions