Single Phase Shunt Active Power Filter for Domestic Non-Linear Loads with Induction Motor Drive

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89 International Journal for Modern Trends in Science and Technology

Single Phase Shunt Active Power Filter for Domestic Non-Linear Loads with Induction Motor Drive

1-6Department of Electrical and Electronics Engineering, Sanketika Institute of Technology and Management, Visakhapatnam, Andhra Pradesh, India

To Cite this Article

P.Narendra, D.Ramakrishna, M.Phaneendra Sai, G.Lokesh Kumar, S.S.L.NaraSimha and Y.Durga Prasad, “Single Phase Shunt Active Power Filter for Domestic Non-Linear Loads with Induction Motor Drive”, International Journal for Modern Trends in Science and Technology, Vol. 04, Issue 03, March 2018, pp.: 89-94.

Active Power Filter (APF) control scheme has proposed to improve the performance of the APF. 3- phase AC voltage controller is employed as a soft-start. Effect of inserting a shunt active filter to provide harmonic and reactive power compensation in a soft-start has been studied. Shunt active filter has been inserted between AC voltage controller and power supply to take care of reactive power requirement of the motor , AC voltage controller and also to provide harmonic compensation. MATLAB/SIMULINK power system toolbox is used to simulate the proposed system.

I. INTRODUCTION

In a modern power system, increasing of loads and nonlinear equipment‟s have been demanding the compensation of the disturbances caused for them. These non-linear loads may cause poor power factor and high degree of harmonics.

Active power filter (APF) can solve problems of harmonic and reactive power simultaneously.

APF‟s consisting of voltage source inverters and a dc capacitor have been researched and developed for improving the power factor and stability of transmission systems. APF have the ability to adjust the amplitude of the synthesized ac voltage of the inverters by means of pulse width modulation or by control of the dc-link voltage, thus drawing either leading or lagging reactive power from the supply. APF‟s are an up-to-date solution to power quality problems. Shunt APF‟s allow the compensation of current harmonics and

unbalance, together with power factor correction, and can be a much better solution than conventional approach (capacitors and passive filters). The simplest method of eliminating line current harmonics and improving the system power factor is to use passive LC filters. However, bulk passive components, series and parallel resonance and a fixed compensation characteristic are the main drawbacks of passive LC filters.

Harmonic compensations have become increasingly important in power systems due to the widespread use Of adjustable-speed drives, arc furnace, switched-mode power Supply, uninterruptible power supply, etc. Harmonics not only Increase the losses but also produce unwanted disturbance To the communication network, more voltage and/or current Stress, etc.

Different mitigation solutions, e.g., passive filter, Active power line conditioner, and also hybrid filter, have been Proposed and used. Recent ABSTRACT

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International Journal for Modern Trends in Science and Technology

ISSN: 2455-3778 :: Volume: 04, Issue No: 03, March 2018

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90 International Journal for Modern Trends in Science and Technology technological advancement Of switching devices

and availability of cheaper controlling devices, E.g., DSP-/field-programmable-gate-array-based

system, Make active power line conditioner a natural choice to compensate For harmonics.

Shunt-type active power filter (APF) is used to eliminate the current harmonics. The dynamic performance of an APF is mainly dependent on how quickly and how accurately the harmonic components Are extracted from the load current.

Many harmonic extraction Techniques are available, and their responses have been explored.

In this project a new concept is proposed that is FBD algorithm in three-phase four-wire shunt active power filter to compensate the harmonics.

In APF design and control, instantaneous reactive power theory was often served as the basis for the calculation of compensation current. In this theory, the mains voltage was assumed to be an ideal source in the calculation process. However, in most of time and most of industry power systems, mains voltage may be unbalanced and/or distorted. Under such scenarios, this theory may not be valid for application.

The p–q theory, since its proposal, has been applied in the control of three-phase active power filters.

However, power system voltages being often non-ideal, in distorted voltage systems the control using the p–q theory does not provide good performance. For improving APF performance under non-ideal mains voltages, new control methods are proposed by Komatsu and Kawabata and Huang and Chen and Hsu. In this paper, the proposed control algorithm

Fig: 1 Block diagram of APF

gives adequate compensating current reference even for non ideal voltage system. Consequently, it is primarily concerned with the development of APF performance under non-ideal or distorted mains voltage conditions. Performance of the proposed scheme has been found feasible and excellent to that of the instantaneous reactive power

algorithms under various non-ideal mains test scenarios.

II. ACTIVE POWER FILTER

Fig.1 shows basic APF block diagram including non-linear load on three-phase supply condition.

In this study, three-phase controlled thyristor bridge rectifier with ohmic–inductive loading are considered as a non-linear load on three-phase ac mains. This load draws non-sinusoidal currents from ac mains and can be controlled by changing its firing angle. APF overcome the drawbacks of passive filters by using the switching mode power converter to perform the harmonic current elimination. Shunt active power filters are developed to suppress the harmonic currents and compensate reactive power simultaneously. The shunt active power filters are operated as a current source parallel with the non-linear load. The power converter of active power filter is controlled to generate a compensation current, which is equal but opposite the harmonic and reactive currents generated from the nonlinear load. In this situation, the mains current is sinusoidal and in phase with mains voltage. A voltage-source inverter having IGBT switches and an energy storage capacitor on dc bus is implemented as a shunt APF. The main aim of the APF is to compensate harmonics, reactive power and to eliminate the unwanted effects of non-ideal ac mains supplies only unity power factor sinusoidal balanced three-phase currents. Shunt active filters are designed to compensate for harmonic currents, reactive power and neutral current by injecting filtering currents into the electric grid. These can be considered as a controlled current source and prove to be particularly effective when their control system provides a good reference tracking. The simplest control technique for current controlled PWM inverters, used as an APF, is hysteresis control. However, at critical points, where changes of reference waveform slope are unpredictable, hysteresis control causes a dangerous increase in switching frequency which cannot be justified, even if it has the advantage of not exceeding the designed error band. The proposed current control, on the other hand, aims to reduce tracking error, by means of a fixed frequency driving signal.

During the switching period in each inverter leg, the control allows the proper state for a longer interval resulting in the quickest possible error reduction. Furthermore, the frequency of the driving signal remains fixed. Active filter regulation is achieved by means of a fuzzy controller which

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91 International Journal for Modern Trends in Science and Technology corrects the amplitude of mains fundamental

current reference in order to move the power balance. In transients and at start up the supply is asked to feed an amount of power different from that absorbed by the load, in order to compensate d.c. side voltage error. The effectiveness of the proposed active filter control was proved in a simulation, where the compensation of the harmonic pollution caused by a hard distorting and unbalanced load is carried out, and is evaluated by means of a performance index.

Harmonic compensation as well as reactive power reduction and line neutral current reduction are achieved by using 10 kHz inverter switching signals

III. POWER QUALITY

The power quality of power supply of an ideal power system means to supply electric energy with perfect sinusoidal waveform at a constant frequency of a specified voltage with least amount of disturbances. Power quality is an issue that is becoming increasingly important to electricity consumers at all levels of usage. Sensitive equipment and non-linear loads are now more commonplace in both the industrial commercial sectors and the domestic environment. Because of this a heightened awareness of power quality is developing amongst electricity users. Occurrences affecting the electricity supply that were once considered acceptable by electricity companies and users are now often considered a problem to the users of everyday equipment. However the harmonic is one of the major factor due to which none of condition is fulfilled in practice. The presence of harmonics, disturbs the waveform shape of voltage and current, and increases the current level and changes the power factor of supply and which in turn creates so many problems.

Fig.2 Basic Compensation Principles

Fig.2 shows the basic compensation principle of a shunt active power filter. It is controlled to

draw/supply a compensating current I from / to the utility, so that it cancels current harmonics on the AC side, and makes the source current in phase with the source voltage. The load current waveform, the desired mains current and compensating current injected by the active filter are containing all the harmonic components to make mains current sinusoidal.

IV. MATLAB/SIMULATION RESULTS APF using HCC for RECTIFIES as a NON-LINEAR LOAD:

Fig.3 Simulink model of APF using HCC for rectifies as a non-linear Load.

Fig.4 Load, Compensation & Source Current for Į = 30^o

Fig.5 FFT analysis of source current with APF for Į

= 30^o.

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92 International Journal for Modern Trends in Science and Technology Fig.6 Load, Compensation & Source Current for Į =

45^o

Fig.7 FFT analysis of source current with APF for Į

= 45^o

Fig.8 Load, Compensation and Source Current for CFL as a Load

Fig.9 FFT analysis of source current with APF for CFL.

Fig.10 Load, Compensation & Source Current for Oven as a Load

Fig.11 FFT analysis of source current with APF for Oven

Fig.12 Load, Compensation & Source Current for Refrigerator as a Load

Fig.13 FFT analysis of source current with APF for Refrigerator

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93 International Journal for Modern Trends in Science and Technology APF using HCC for RECTIFIES as a NON-LINEAR

LOAD with INDUCTION MOTOR DRIVE

Fig.14 Simulink model of APF using HCC for rectifies as a non-linear Load with Induction Motor

Drive.

Fig.15 Simulation Results of Current, Speed and Torque for Induction Motor Drive.

V. CONCLUSION

The presented single-phase Shunt Active Power Filter has demonstrated to be able to compensate the harmonic currents and the power factor produced by loads, making the current at the source side to become almost sinusoidal and in phase with the system voltage. This current compensation can also prevent voltage harmonics.

APF simulation using MATLAB Simulink is proven to be very useful for studying the detailed behavior of the system for harmonic and unbalance compensation, under steady state and transients.

In all, it can be stated that a shunt active filter can be very useful to reduce the current amplitude and Pollution level substantially when an AC voltage controller fed induction motor drive is employed in certain applications like fans or centrifugal pumps.

This will be a very useful scheme especially in industries where multiple induction motors of large capacity are frequently started from a 3-phase supply.

ACKNOWLEDGMENTS

The authors would like to express their gratitude to Dr. S.V.H Rajendra, Secretary, Alwardas Group of Educational Institutions, Mrs. Madhu Bhatt, Executive Officer, Alwardas Group of Technical Institutions, Mr.K.S.P.Rao, Director (HR and Administration), Alwardas Group of Technical Institutions and Dr. C. Ghanshyam, Principal, Sanketika Institute of Technology and Management for their encouragement and support throughout the course of work. The authors are grateful to Dr. N.C. Anil, Vice-Principal, Sanketika Institute of Technology and Management and staff members for providing the facilities for publication of the paper.

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