SILPA V S7 F ROLL NO: 58

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NEW HYBRID POWER CONDITIONER

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• Introduction• Before hybrid power conditioner• Hybrid power conditioner• New hybrid power conditioner• Three phase four wire hybrid filter• System configuration• Control principle• Control block diagram• Experimental results• Advantages• Applications• Conclusions• References

CONTENTS

INTRODUCTION

Proposed for suppressing harmonic currents and neutral line current.Employed in three phase four wire distribution system.Consists of neutral line current attenuator and a hybrid power filter.Hybrid power filter consists of three phase power convertor and three phase tuned power filter.

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Zig-zag transformer: Connected to the load in parallel depends the ratio between utility and zig-zag transformer

Zig-zag transformer with single phase power converter : inserted at neutral line fluctuation in the ground voltage of the load

Series of active power filters: connected to the neutral line between the utility and load fluctuation in ground voltage of the load

BEFORE HYBRID POWER CONDITIONER

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Passive power filters :advantage of low hardware cost, affected by system impedance, large volume, parallel resonance and series resonance

Power semiconductor technology : Active power filters suppress the neutral line current capacity and manufacturing cost of power converter is very high

CONTINUED

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HYBRID POWER CONDITONER Developed to solve the problems of active and passive power

conditioners

HPF consists of passive power filter and a power converter

Passive power filter reduce the capacity of power converter

Power converter improve the filter characteristics of passive power filter

HPF is divided into series linked and shunt linked type

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Power converter connected between the utility and load through a linked transformer in series linked type.

Passive power filter is parallel to the load Power converter is connected to the passive power filter in

series and then connected to load in parallel in shunt type.

HPC CONT

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Hybrid power conditioner: 1. neutral line current attenuator, 2. hybrid power filter.

Hybrid power filter : 1. three phase power converter, 2. three phase tuned power filter

Neutral line current attenuator to attenuate neutral line current

Can effectively reduce the power rating of passive and active elements

NEW HYBRID POWER CONDITIONER

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THREE PHASE FOUR WIRE HYBRID POWER FILTER

Fig 1. Configuration of the conventional shunt type hybrid filter

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Configuration of a conventional shunt type hybrid power filter.

Power converter series with power filter connected to the load in parallel.

Passive power filter three phase tuned power filters with an inductor and a capacitor connected in series.

Utility voltage drop on the passive power filter dc bus voltage and voltage rating reduced harmonic current and fundamental reactive currents not diminished.

CONTINUED

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CONTINUED

Fig.2 Configuration of the advanced hybrid power filter

CONTINUEDTo reduce the power rating of the power converter.Power convertor connected to the inductors of the three phase tuned power filter in parallel.Reactive current and harmonic current flows through the inductors decreasing the current flowing through the power converter.

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Major role is to filter the harmonic currents of the load. Neutral line current of the load contains a fundamental

component in unbalanced three phase loads. Conventional type cannot suppress the neutral line current

under the unbalanced load.

SHUNT TYPE HYBRID POWER FILTER

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NEW HYBRID POWER CONDITIONER-SYSTEM CONFIGURATION

Fig 3. System configuration

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A neutral line current attenuator is integrated into the hybrid filter

Advance the filter performance under the unbalanced load With an increase in tuned frequency of the tuned power filters

volume and weight of the tuned power filter reduced

Neutral line current attenuator phase voltage drop on capacitors volume and weight of the transformer reduced

CONTINUED

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Current mode control-to control the three phase power converter of the hybrid power filter

Ica= K1Isah+K2VSA1

Icb=K1Isbh+K2Vsb1

Icc=K1Isch+K2Vsc1

Isah, Isbh , Isch = harmonic components of the three phase utility currents.

VSA1 , Vsb1 Vsc1 =three phase fundamental voltages of the utility.

First term - suppress the non zero sequence harmonics Second term - regulate the dc bus voltage Reactive current of tuned power filters and harmonic currents

of the load-flows through the inductors - suppression attained

CONTROL PRINCIPLE

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Feedforward control- adopts in single phase power converter Vcon=kcon Vm

kcon = gain of the single phase converter Vm =modulation signal of the PWM circuit. The gain of the single phase converter is kcon=Vdc/Vtri

Vdc = bus voltage Vtri = amplitude of the carrier of the PWM circuit. Neutral line current of the utility is detected, amplified and

sent to PWM circuit. Vcon= kconk3Isn , k3 =feedforward gain

CONTINUED

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CONTROL BLOCK DIAGRAM

Fig 4.Control block diagram of the three phase and single phase power converters

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The current references contain fundamental signal and harmonic signal

The band stop filters are used to extract harmonic signals Fundamental signal is obtained as the result from the

multiplier The current references are sent to controllers The output of controllers sent to PWM circuit

CONTINUED

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To control single phase converter Neutral line current obtained by summing up detected three

phase utility currents Output of amplifier circuit sent to PWM circuit The control blocks of three phase and single phase power

converters can integrated into a digital signal processor chip

CONTINUED

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Fig 4. Main parameters of the prototype

EXPERIMENTAL RESULTS To verify the performance prototype is developed and tested with line voltage of 220V

and frequency of 60 Hz The main parameters are given in table

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EXPERIMENTAL RESULTS UNDER BALANCED LOAD

Fig 5. Balanced three phase load and hybrid power conditioner under the balanced three phase loadTotal harmonic distortion of the load current is 47% and neutral line current of load is 11.2AShows the utility currents after being compensated by HPCThe three phase utility current are nearly sinusoidal and THD is 3.9% and neutral line current is .81A

EXPERIMENTAL RESULTS UNDER UNBALANCED LOAD

Fig 6. Results of unbalanced three phase load and hybrid power conditioner under the unbalanced three phase loadThe results of unbalanced three phase load currents and neutral load currentOnly a single phase rectifier is applied between the phase a and neutral lineThree phase utility currents are sinusoidal and THD are 7.35% , 4.71% and 3.23% res. And neutral line current is .96A

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Enhancing operation efficiency The power capacity of power converters in the hybrid power

filter and neutral line current attenuator can be effectively reduced

Suppress neutral line current and harmonic currents

ADVANTAGES

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Three phase four wire distribution systems applied to low voltage applications

Applicable whether the load is balanced or not

APPLICATIONS

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A new hybrid power conditioner composed of a hybrid power filter and a neutral line current attenuator is proposed.

Power capacity of power converters reduced and enhancing the operation efficiency

Effective solution to the problems of harmonic currents and neutral line current in three phase four wire distribution system

CONCLUSION

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[1]Jinn-Chang Wu,Hurng –Liahng Jou and Shun- Tian Xiao, “A new hybrid power conditioner for suppressing harmonics and neutral line current in three phase four wire distribution power systems,”, IEEE Trans. Power Del., vol.29,no. 4 Aug 2014.

[2]B Singh, P. Jayaprakash and D.P.Kothari, “Reduced rating VSC with a zig-zag transformer for current compensation in a three phase four wire distribution system,” IEEE Trans. Power Del., vol.24,no. 1,pp. 249-259,Jan. 2009.

[3]R. M.Ciric, L.F.Ochoa , A. Padilla-Feltrin and H. Nouri , “Fault analysis in four wire distribution networks,” Proc. Inst. Elect .Eng., Gen., Transm . Distrib ., vol. 152,no.6,pp.977-982,2005.

REFERENCES

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THANK YOU……….