analysis of shunt apf (active powerfilter)

AN ANALYSIS OF SHUNT ACTIVE POWER FILTER BASED ON INSTANTANEOUS

REACTIVE POWER THEORY

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Batch Members

A. Saroja Padma vathi (09MN1A0203)D. Rajesh (09MN1A0213)S. Jakeer Hussain (09MN1A0239)K. Tarakeswara Rao (10MN5A0202)

Project Guide

P. Taviti Naidu sirAsst. Prof. Dept. of EEE

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ABSTRACT

Shunt Active Power Filter is an ideal device that could manage the harmonic compensation in an adjustable and dynamic manner. This article reviews the basic principle of shunt active power filter, along with the current tracking circuit based on the instantaneous reactive power theory and the main circuit performing as an inverter with PWM hysteresis control. A comprehensive control method is analyzed and a harmonic compensation simulation is conducted, the result of which verifies the harmonic detection algorithm is well-proposed and the power quality of the grid is overall-enhanced.

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INTRODUCTION

Harmonic suppression and reactive power Compensation are essential for the construction of smart grid, which gathers, distributes, and acts on the behavior of suppliers and consumers in order to improve the efficiency and sustainability of electric services. With the increasingly widespread application of power electronic device, such as electronic appliances, switching model power supplies and electronic ballasts, the harmonic contamination they produce in grid has given rise to a variety of safety concerns.

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EXISTING METHODS TO ELIMINATE HARMONICS

By increasing the pulse number

Passive Filters

Active Filters

Notching & Noise

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ADVANTAGES

Response is high

Active filter is capable of handling harmonics ranging between fluctuating frequencies

It can be operated at lower order harmonic

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DISADVANTAGES

Whenever our load changes, the filter value also changes.

It can not provide flexible compensation

It causes resonance problems

Needs cooling system

Not suitable for higher order harmonics

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SHUNT ACTIVE POWER FILTER

Along with increasing demand on improving quality, the most popular technique that has been used is active power filter (APF); this is because APF can easily eliminate unwanted harmonics, improve power factor and overcome voltage sags.

It is a combination of inverter and capacitor.

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BLOCK DIAGRAM

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REFERENCE CURRENT CALCULATION

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CURRENT CONTROL CIRCUIT

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MAIN CIRCUIT PARAMETER DESIGN

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MAIN CIRCUIT WORKING

The working mode of the main circuit is determined by the condition of its six switches. Generally speaking, there is always a single device switched on in all three groups (S1/S4, S3/S6 or S2/S5), constructing six different combinations all together.

Ka is 1/3 when lower bridge arm is working.Ka is -2/3 when upper bridge arm is working.

SSITMATLAB/SIMULINK MODELING OF NON-LINEAR LOAD

WITHOUT APF

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WAVEFORMS OF LOAD CURRENT AND POWER FACTOR

Load current Waveforms before connecting the APF to the distribution line

Power factor Waveforms before connecting the APF to the distribution line

SSITMATLAB/SIMULINK MODELING OF NON-LINEAR LOAD WITH APF USING BUTTERWORTH FILTER

SSITWAVEFORMS OF LOAD CURRENT AND POWER FACTOR

USING APF

Load current Waveforms after connecting the APF to the distribution line

Power factor Waveforms after connecting the APF to the distribution line

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TOTAL HARMONIC DISTORTION

The THD is defined as the ratio of the rms value of the harmonic components to the rms value of the fundamental component and usually expressed in percent. This index is used to measure the deviation of a periodic wave form containing harmonics from a perfect sine wave. For a perfect sine wave at fundamental frequency, the THD is zero.

Thd > 5 , Harmonics are presentThd < 5 , Harmonics are absent

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FFT ANALYSIS OF LOAD CURRENT WITHOUT APF

SSITFFT ANALYSIS OF LOAD CURRENT

WITH APF

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ANALYSIS OF HARMONIC CURRENT

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APPLICATIONS

FACTS Devices

Smart GRID systems

HVDC converters

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CONCLUSION

On the basis of the simulation, the article utilizes the

instantaneous reactive power theory (ip-iq calculating approach) to

detect harmonic wave and reactive load current efficiently, compensate

the load current effectively by reshaping the source current to that

similar to sine wave and reducing the THD value to below 5%. The

compensation performance of the simulation result provides a practical

approach to the basis of APF application in smart grid system.

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Thank You

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