Power Quality Improvement using Shunt Hybrid Power Filter

This project report presents design, simulation and development of passive shunt filter and shunt hybrid power filter (SHPF) for mitigation of the power quality problem at ac mains in ac-dc power supply feeding to a nonlinear load. The power filter is consisting of a shunt passive filter connected in series with an active power filter. At first passive filter has been designed to compensate harmonics. The drawback associated with the passive filter like fixed compensation characteristics and resonance problem is tried to solve by SHPF. Simulations for a typical distribution system with a shunt hybrid power filter have been carried out to validate the presented analysis. Harmonic contents of the source current has been calculated and compared for the different cases to demonstrate the influence of harmonic extraction circuit on the harmonic compensation characteristic of the shunt hybrid power filter

A new design algorithm for hybrid active power filter

The correct determination of the parameters of Hybrid Active Power Filter (HAPF) plays a decisive role in its performance. Therefore, this paper proposes a new design algorithm for HAPF based on the Social Spider Algorithm (SSA). This algorithm has the advantage that it is possible to determine the parameters of both the power circuit part and the control circuit part of HAPF. The achieved results are multi-purpose, such as: minimum total harmonic distortion of the supply current and source voltage, the maximum reactive power compensation into the system and satisfy many constraints such as: system stability, resonance conditions of the branches and the limits of the parameters. Compared to traditional design method using the Particle Swarm Optimization algorithm, the proposed algorithm shows the advantages of smaller total harmonic distortion of supply current and source voltage, and higher reactive power compensation into the grid while still meeting the constraints

Simulation and Performance Evaluation of Shunt Hybrid Power Filter for Power Quality Improvement Using PQ Theory

This work proposes the design of shunt hybrid filter using instantaneous power theory to improve the power quality and simulation has been carried out for 3 phase distribution system feeding different types of non linear loads. The proposed filter consists of parallel combination of 5th and 7th tuned selective harmonic elimination passive filters, which is connected in series with a small rating IGBTs based voltage source inverter. In this work, principle of compensation and filtering behavior of the system has been discussed in detail. Instantaneous real and reactive power theory based controller has been designed to estimate the reference current from the distorted current. In order to reduce the harmonics, generated reference currents are tracked by voltage source inverter using hysteresis band current controller. The performance of the hybrid scheme is evaluated for various nonlinear loads using Matlab/ Simulink tool. The detailed analysis has been carried out on harmonics reduction and DC bus voltage regulation and the simulation result ensures the feasibility of suggested control strategy. The proposed topology improves the filtering performance of the passive filter in hybrid scheme

Rating optimization of three phase series hybrid power filter for power quality compensation and renewable energy integration

Hybrid series active filters and shunt passive filter can significantly improve power quality and ensure a reliable voltage supply to the load through mitigating or eliminating issues such as voltage distortions, sags, swells, and unbalances. They can also compensate current problems related to linear and non-linear loads, such as load reactive power, current harmonics. In this thesis study, a 3-phase hybrid series power filter for power quality compensation is used for current harmonic, reactive power compensation, unbalance/sag/swell grid voltage compensation. A major research in this thesis concerns an approach to compensate simultaneously a reactive power by removing a TCR converter proposed in the paper published which has an impact on the reduction of the cost of the three phases series hybrid filter. Other research concerns the comparison of two approaches of the design of the passive filter to evaluate the impact on the series active filter rating. The hybrid series active filter (HSeAF) has gained in popularity as a highly efficient power electronics-based active power compensator. Without the active portion of the HSeAF, a shunt passive filter is unable to resolve voltage problems on its own as a dynamic voltage restorer. A conventional HSeAF 3-phase system comprises three series isolation transformers connected to a 3-phase converter sharing a common DC link bus. It is controlled as a variable voltage source similar to a shunt active power filter, the latter which is tuned for harmonic frequencies and installed to create an alternative path for load current harmonics. The existing literature focuses on using hybrid active power filters to compensate for load current issues only, due to the complexity and expense of the devices. The present research looks instead at optimizing available resources in order to enhance product efficiency and reduce overall costs. Also an approach provides smarter use of the shunt passive filter; along with a reduced series active filter rating and an overall reduction in cost. MATLAB simulations show that the 3-phase SHPF is able to simultaneously resolve voltage problems and load current issues

PSO-GWO Optimized Fractional Order PID Based Hybrid Shunt Active Power Filter for Power Quality Improvements

This paper presents a Hybrid Shunt Active Power Filter (HSAPF) optimized by hybrid Particle Swarm Optimization-Grey Wolf Optimization (PSO-GWO) and Fractional Order Proportional-Integral-Derivative Controller (FOPIDC) for reactive power and harmonic compensation under balance and unbalance loading conditions. Here, the parameters of FOPID controller are tuned by PSO-GWO technique to mitigate the harmonics. Comparing Passive with Active Filters, the former is tested to be bulky and design is complex and the later is not cost effective for high rating. Hence, a hybrid structure of shunt active and passive filter is designed using MATLAB/Simulink and in real time experimental set up. The compensation process for shunt active filter is different from predictable methods such as (p-q) or (id-i ) theory, in which only the source current is to be sensed. The performance of the proposed controller is tested under different operating conditions such as steady and transient states and indices like Total Harmonic Distortion (THD), Input Power Factor (IPF), Real Power (P) and Reactive Power (Q) are estimated and compared with that of other controllers. The parameters of FOPIDC and Conventional PID Controller (CPIDC) are optimized by the techniques such as PSO, GWO and hybrid PSO-GWO. The comparative simulation/experiment results reflect the better performance of PSO-GWO optimized FOPIDC based HSAPF with respect to PSO/GWO optimized FOPIDC/CPIDC based HSAPF under different operating conditions.

Hybrid Active Power Filter: Design Criteria

The configuration of a series active power filter (APF) and a parallel passive filter (PPF) has proven to be an efficient system for nonlinear load compensation. For this topology, different compensation strategies have been proposed to control the series APF. The most effective strategy determines the APF refrerence voltage as a proportion of the source current harmonics. The proportionality constant in the control algorithm implementation is related to the APF gain and the system dynamics. In this paper, the system state model has been obtained for three control strategies of series APF: voltage proportional to source current harmonics, voltage opposite to the load voltage harmonics and a hybrid strategy which combines both previous. The resulting model analyses provide the information needed to establish design criteria for each strategy, both in terms of harmonic filtering and the system stability. The three strategies were compared in two different situations: sinusoidal supply voltages and distorted supply voltages. Finally, results of an experimental prototype developed for this purpose allowed the proposed analysis to be verified

Comparison of different optimization criteria for optimal sizing of hybrid active power filters parameters

Praise Worthy Prize granted a permission for Brunel University London to archive this article in BURA.Harmonic distortion in power systems has increased considerably due to the increasing use of nonlinear loads in industrial firms and elsewhere. This distortion can give rise to overheating in all sectors of the power system, leading to reduced efficiency, reliability, operational life and sometimes failure. This article seeks to propose a new methodology for the optimal sizing of hybrid active power filter (HPF) parameters in order to overcome the difficulties in hybrid power filters design when estimating the preliminary feasible values of the parameters. Sequential Quadratic Programming based on FORTRAN subroutines is used to find out the planned filter size in two different optimization criteria depending on design concerns. The first criterion is to minimize the total voltage harmonic distortion. The second one is to maximize the load power factor, while taking into account compliance with IEEE standard 519-1992 limits for the total voltage harmonic distortion and the power factor.The effectiveness of the proposed filter is discussed using four exemplary case

Design of Passive High Pass Filter for Hybrid Active Power Filter Applications

In recent years there has been considerable concern over power quality, at both distribution and consumer levels, and the need to control reactive power and voltage stability at transmission levels. Active filtering of electric power has now become a mature technology for harmonic and reactive power compensation in two-wire (single phase), three-wire (three phase without neutral), and four-wire (three phase with neutral) ac power networks with nonlinear loads. Active power filter and passive filters (APF & PF) are the traditional ways of compensating for harmonics. However, both of the two ways have some disadvantages, namely resonance and tuning problems in passive filters, and capacity, initial and running cost in APF. Hybrid Active Power Filter (HAPF) has been proposed to overcome the disadvantages of APF and PF. It is a combined system of PF and APF. Appropriate choice of PF and detailed design method for the same is being presented in this thesis, which when combined with APF will eliminate the higher order harmonics. A simple mathematical design procedure is derived for the passive high pass filter. In this thesis, power quality improvement based on HAPF is analyzed for a nonlinear RL-load connected to a 1-phase ac supply which can simultaneously improve the power quality and control the reactive power requirement of the load. The switching algorithm for the APF is presented. The design procedure is limited to the design of passive HPF. However using the designed PF along with existing system consisting of APF is improving the power quality. The obtained results of the proposed HAPF is compared with the existing system with only APF in terms of source current and source voltage spectrums, active & reactive power flow from the filter side to the power system at the point of common coupling (PCC). The studied system is modeled and simulated in the MATLAB/Simulink environment. The performance indices included are THD analysis of source voltage, source current

A Hybrid Active Filter Using the Backstepping Controller for Harmonic Current Compensation

This document presents a new hybrid combination of filters using passive and active elements because of the generalization in the use of non-linear loads that generate harmonics directly affecting the symmetry of energy transmission systems that influence the functioning of the electricity grid and, consequently, the deterioration of power quality. In this context, active power filters represent one of the best solutions for improving power quality and compensating harmonic currents to get a symmetrical waveform. In addition, given the importance and occupation of the transmission network, it is necessary to control the stability of the system. Traditionally, passive filters were used to improve energy quality, but they have endured problems such as resonance, fixed remuneration, etc. In order to mitigate these problems, a hybrid HAPF active power filter is proposed combining a parallel active filter and a passive filter controlled by a backstepping algorithm strategy. This control strategy is compared with two other methods, namely the classical PI control, and the fuzzy logic control in order to verify the effectiveness and the level of symmetry of the backstepping controller proposed for the HAPF. The proposed backstepping controller inspires the notion of stability in Lyapunov’s sense. This work is carried out to improve the performance of the HAPF by the backstepping command. It perfectly compensates the harmonics according to standards. The results of simulations performed under the Matlab/Simulink environment show the efficiency and robustness of the proposed backstepping controller applied on HAPF, compared to other control methods. The HAPF with the backstepping controller shows a significant decrease in the THD harmonic distortion rate

New trends in active filters for improving power quality

Since their basic compensation principles were proposed around 1970, active filters have been studied by many researchers and engineers aiming to put them into practical applications. Shunt active filters for harmonic compensation with or without reactive power compensation, flicker compensation or voltage regulation have been put on a commercial base in Japan, and their rating or capacity has ranged from 50 kVA to 60 MVA at present. In near future, the term of active filters will cover a much wider sense than that of active filters in the 1970s did. The function of active filters will be expanded from voltage flicker compensation or voltage regulation into power quality improvement for power distribution systems as the capacity of active filters becomes larger. This paper describes present states of the active filters based on state-of-the-art power electronics technology, and their future prospects toward the 21st century, including the personal view and expectation of the author</p