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Widely distributed single-phase power electronic rectifier loads are increasing source of harmonics in power distribution system. These harmonics have many well known adverse impacts on the power system. So it is necessary to improve the power quality of the rectifiers. This paper presents a novel single phase rectifier in which capacitors are used in parallel with diodes in one leg of the rectifier...
Traditional 2-level voltage source inverter (VSI) based active power filters (APF) has a high DC voltage across the capacitor. A pure APF connected to a 3-ϕ 400V line voltage, will have a DC voltage of more than 600V for its effective working. Active switches in the inverter subjected to this voltage, results in a high voltage stress. Multi-level inverter topology in APF reduces the voltage stress...
In this paper, a new methodology combined with Harmonic Loss Sensitivity Factor (HLSF) and Direct Search Algorithm (DSA) has been proposed for optimal placement of capacitor on unbalanced and harmonically distorted three phase radial distribution system. In other words, an aggregate harmonic loss sensitivity factor, i.e., including fundamental component is used to decide the prospective optimal locations...
In this paper a front-end converter having third harmonic current injection technique is used for improving input current shape as near sinusoidal. Here zig-zag transformer is used as the current injection device so that the advantages pertaining to zig-zag transformer is utilized effectively. The third harmonic current injection device along with the three-level boost converter at the output stage...
Overheating in the equipment and conductors can be primarily caused by harmonics in power systems. Decrease of harmonics is considered necessary, especially when capacitor banks exist. Using a detuned harmonic filter is a traditional solution. Current limiting reactors (CLR) can be an economical solution to damp harmonic pollution if installed in the optimal location. In this paper, power system studies,...
Modulation techniques for the modular multilevel converter consider that the total number of sub-modules in the phase-leg is, either instantaneously or on average, equal to N balancing the capacitor voltages to a constant reference. This paper proposes an offset PWM technique that utilises the total number of the SMs in the arms of the MMC, particularly under low modulation indices. The result is...
By the way of establishment of mathematical model for three-phase four-wire T-type three-level Active Power Filter (APF), the relation of DC-link voltage difference, the neutral current and the duty-ratio of each bridge arms are revealed. Consequently, a control strategy of DC-link voltage balancing is proposed with the controllable neutral current injection, which is easier to be realized and more...
In this paper, the topology of distribution static compensator (DSTATCOM) with a three-phase four-wire system is modified. The modification concerns with the interfacing filter and DC-link capacitor with a goal of improving the system power factor, stabilizing the system voltages and eliminating the harmonic distortion resulting from nonlinear loads. The modified DSTATCOM has a three-leg inverter...
In this paper, active power decoupling using six switch rectifier with a built-in ripple port (inductive or capacitive or combination of both) to reduce the size of the E-cap is studied. The six switch rectifier is analyzed as a three-port converter: (i) AC source at the input port, (ii) a load at the DC output port, and (iii) an inductor or capacitor connected to the third port called ripple port...
The superior harmonic performance of the modular multilevel converter facilitates reduction in passive filtering requirements. However, in practice, any volume and weight reduction brought about by using smaller filtering components, is offset by the increase in stored capacitor energy inside the converter. This paper proposes injection of high-frequency circulating currents and zero-sequence voltages,...
Multilevel cascaded converters for use in battery energy storage systems (BESSs) can utilise parallel-connected dc/dc conversion stages. These stages decouple each battery string voltage from the associated H-bridge capacitor voltage. Decoupling prevents second harmonic current ripple flowing in the batteries and compensates for variation in battery voltage due to state of charge. Instead of parallel-connected...
In the literature, passive filters have been commonly used to mitigate the harmonic currents in industrial distribution systems because they are inexpensive, simple, and reliable. The aim of this paper is presenting different design methods for multiple-arm shunt passive filters based on various reactive power sharing approaches for an industrial distribution system of a petrochemical plant in Egypt...
The study is concerned with the optimal penetration of renewable energy sources and their impacts on power quality case studies into distribution systems. Non-linear loads are the main harmonic sources in a distribution grid while the PV system constitutes power converters which are large generating source of harmonics. Therefore, both nonlinear loads and PV systems have large impact on the power...
This paper proposes a method to enhance the power quality of the medium voltage multilevel inverter based induction motor drive system. An 18-pulse AC-DC converter is used to feed a 27-level inverter based vector controlled induction motor drive (VCIMD). Using this configuration, the input supply current distortion decreases to meet the demand of an IEEE-519 standard. The distortion in the 27-level...
This paper presents a Minor Component Analysis Based Anti-Hebbian Neural Network (MCA based AHNN) algorithm with adaptive step size convergence parameter for decoupled voltage and frequency control of single phase standalone Nano-hydro generation systems. In the proposed control scheme the adaptive step size convergence (ASSC) parameter significantly improves the convergence property of the algorithm...
This paper presents the design & analysis of D-STATCOM using ICCT with conventional controllers to improve the power quality. The use of AC circuits in electrical power system has been a common practice nearly since the very inception of the interconnected power network. The most familiar loads on such a system were the constant power, constant impedance and constant current loads or a linear...
This paper investigates performances of Modified Widrow-Hoff ADALINE as harmonics extraction algorithm under effect of photovoltaic (PV) integrated with shunt active power filter (SAPF). Integration of PV with SAPF gives high advantages in terms of energy source and power quality. The dependable on grid supply current reduces as PV current may support good amount of current to the load. However, with...
In recent years, the majority of the research has focused on grid-tied transformerless PV inverters, more capable than traditional grid-tied line transformer-based PV inverters, but more critical from a power quality point of view, especially in terms of common mode voltage and ground leakage current. Neutral point clamped (NPC) converters have recently gained popularity due to high efficiency and...
This paper presents the performance and comparative analysis of Static Synchronous Compensator (STATCOM) based on 6, 12 and 48-pulse VSC configuration. STATCOM is implemented for regulation of the voltage at the Point of Common Coupling (PCC) bus which has time-variable loads. The dq decoupled current control strategy is used for implementation of STATCOM, where modulation index M and phase angle...
This paper proposes a three-phase single stage power factor corrected (PFC) bridgeless modular zeta converter based switched mode power supply (SMPS) suited for welding applications demanding high current and low voltage at the output. Typically, for high-power welding applications, modular arrangement of converters is suggested to reduce the device rating and provide ease of power expandability as...
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