implementation of echo-state network based control for...

Implementation of Echo-State Network Based Control for Power

Quality Improvement

CH.SOMASEKHAR, DEPARTMENT OF ELECTRICAL AND ELECTRONICS

ENGINEERING, N.B.K.R. INSTITUTE OF SCIENCE AND TECHNOLOGY

(Autonomous), Affiliated to JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY,

ANANTAPUR, MASTER OF TECHNOLOGY with POWER SYSTEMS as specialization,

Project Guide Head of the Department

Dr. N.USHA Dr. S. SURESH REDDY

Professor Professor

Abstract—

This paper proposes a replacement management rule

for mitigation of power quality issues at the

distribution level. The management rule is meant on

the idea of echo-state network that may be a form of

perennial neural network. This technique is employed

to extract basic weight parts from non-sinusoidal load

currents. These weight parts square measure used to

appraise grid currents and consequently generate

change logic for the voltage supply convertor utilized

in the active filter. The shunt connected active filter

with the proposed management rule is employed to

beat many current related power quality issues and

provides the load compensation. issues reminiscent of

the presence of lower order harmonics, meagre

reactive power and cargo unbalancing square

measure corrected employing a shunt filter in each

the facility issue correction (PFC) and voltage

regulation (VR) modes. The projected management

algorithm is valid on a true time system that may be a

paradigm of a shunt filter. The rule is tested in

MATLAB victimizationSim Power Systems and

SIMULINK and enforced on a digital signal

processor.

Index Terms— Power quality, harmonics, shunt

active filter, echo state network, recurrent neural

network.

I. INTRODUCTION:-

Electric power framework is getting dirtied because

of an expansion in control gadgets based converters

in family apparatuses and modern hardware.

Generous increment in nonlinear burdens, for

example, converters, switch mode control supplies

(SMPS), circular segment heaters, electric/electronic

release lighting, variable speed drives, PCs, fax

machines and house hold electronic gear introduced

at the dispersion level assume a noteworthy part in

contorting the sinusoidal waveform of supply

voltages and streams. The primary worry of power

purchasers is to acquire uninterruptable power supply

with enhanced power quality. For the electrical

utility, there are a few delicate burdens viz. doctor's

facilities and preparing plants that require unpolluted

and uninterruptable electric power supply [1]. In this

way, to guarantee quality capacity to all customers

notwithstanding when a portion of the heaps are

themselves dirtying in nature, turns into a noteworthy

test.

The power quality issues identified with streams are

primarily sounds, inadequate receptive power and

uneven burdens and these influence the execution of

other hardware, which are coupled at purpose of

basic association (PCC). Universal measures have

been prescribed to indicate the passable furthest

reaches of control quality issues and to give rules to

the end client, maker and utility to enhance the nature

of intensity [2]-[3]. The relief of music and other

power quality issues are critical assignments of

service organizations. Today shunt dynamic power

channels (SAPFs) are the well known decision in

accomplishing great power quality levels. The SAPFs

are used for sounds concealment, responsive power

age/ ingestion and giving remunerating streams to

adjust the stack. An execution of a shunt dynamic

channel in a cost viable way, ends up conceivable in

light of striking advancement in territory of

semiconductor gadgets identified with power and flag

handling [4]. Research around there has driven to

advancements in the territory of various setups and

control calculations for the control of the shunt

dynamic channel. Akagi et al. [5] have talked about a

three stage compensator controlled by prompt

responsive power procedure. Singh et al. [6] have

created control adjust hypothesis for dynamic power

channel for coordinating AC mains genuine power,

receptive power stream what's more, music from the

dynamic channel to the heap. Rao et al. [7] have

talked about quick symmetrical part hypothesis

International Journal of Research

Volume 7, Issue XII, December/2018

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Page No:1394

(ISCT) for remuneration under three stage adjusted/

uneven supply voltages and the focal points and

downsides of these control calculations are

introduced in view of different current and voltage

related power quality issues. Silva et al. [8] have

exhibited control in view of changed synchronous

reference outline (MSRF) for SAPF.

A versatile control hypothesis depends on the

programmed alteration of controller in a composed

and ascertained way amid the control task by

changing procedure parameters [9]. Various

distributions are accessible on control calculations for

SAPF in view of versatile control, for example,

versatile step channel , Wiener and minimum mean

square (LMS) channels, recursive minimum square ,

enhanced straight sinusoidal tracer , recurrence

versatile partial request monotonous control, safe

input controller , and recursive slightest square (RLS)

control in which the joining rate and following

abilities are controlled by factor overlooking variable.

The field of computerized reasoning has been

perceived as a great instrument for the outline of

appropriate controllers and following. These control

calculations have the ability of learning, self-

arranging or self-adjusting. Fake neural system

(ANN) and fluffy surmising framework based

controllers alongside their changed blends are

introduced in the writing.

The reverberate state arrange procedure otherwise

called sort of intermittent neural system (RNN) has

been discovered reasonable for principal weight

extraction from mutilated load streams. The proposed

arrange indicates impressive preparing

expeditiousness and following properties than

different sorts of repetitive neural system. Quick

preparing rate of resound state arrange has made this

strategy reasonable as a framework identifier and

shut circle controller in control framework. Some

different points of interest incorporate great dynamic

reaction making it reasonable for ongoing

applications. Because of these attributes, this system

has been utilized for changed applications, for

example, satellite station balance multimachine

control framework, recognizable proof of load sounds

and so on. In this paper, the resound state organize is

connected for the calculation of basic parts of load

streams from non-sinusoidal load streams. These

parts of load streams so acquired are then prepared

for estimation of reference matrix streams. This sort

of system is straightforward and simple to actualize.

All SAPF highlights, for example, music dismissal,

remuneration of load receptive power and load

unbalancing are executed in both the control modes

utilizing reenactment and trial thinks about on the

framework. Results with a resound state organize

control calculation are analyzed with the SRFT and

LMS control calculations on a few parameters.

II. SYSTEM CONFIGURATION:-

A three-stage, AC mains with lattice impedance,

indicated utilizing arrangement resistive inductive

(𝑅𝑆-𝐿𝑆) branch, sustains a three stage nonlinear load

as appeared in Fig. 1. The SAPF is planned utilizing

three-leg voltage source converter (VSC) which

utilizes two protected entryway bipolar transistors

(IGBTs) with hostile to parallel diodes in every one

of the three legs and DC connect capacitor (𝐶𝑑𝑐) at

DC side. Three inductors (𝐿𝑓) are utilized to couple

the VSC to the framework. Uninvolved channels

involve arrangement associated resistive (𝑅𝑓 ) and

capacitive (𝐶𝑓) components coupled to the PCC, and

these are reasonably stifled exchanging clamor of

VSC. A diode connect rectifier having R-L

arrangement components speaks to nonlinear load

and is characteristic of the real load that infuses

sounds in the AC framework. The scaled model of

SAPF is actualized in the research center (with VSC)

and resound state organize control is executed by

methods for DSP (dSPACE 1104 R&D controller)

implanted in the PC.

Fig. 1 Configuration of three-phase SAPF

III. CONTROLLER DESIGN:-

The reverberate state organize control calculation is

created for the calculation of essential current parts.

The extraction of weight segments alongside

development of reference streams and gating beats is

depicted here.



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A. Computation of Fundamental Active

Current Components of Reference Grid

Currents:-

The complete block diagram of control algorithm

incorporating echo- state network technique is shown

in Fig. 2. Three phase voltages (𝑉𝑆𝑎, 𝑉𝑆𝑏and 𝑉𝑆𝑐) at

the PCC are sensed and their peak value is

determined as follows,

Using PCC voltage magnitude, the unit inphase

components are calculated as,

The low pass filter of 12 Hz bandwidth is used to

suppress AC ripples in the sensed DC bus voltage. A

proportional-integral (PI) controller over DC link

voltage regulates it to reference (𝑉𝑑𝑐∗ ). The output of

this controller at 𝑛𝑡ℎ sampling moment is computed

as follows,

where the gains of PI controller are as 𝑘𝑝𝑑 and 𝑘𝑖𝑑 .

The fundamental equation describing a computation

of active power weights of load currents as described

in [23] is as,

where ‘e’ is error computed between sensed load

current (𝑖𝑙) and estimated load current (𝑖𝑒𝑠𝑡), x(n) is

input vector, η and γ are defined as learning and

momentum gains. Both the learning and momentum

gains vary in a range of 0 to 1 and the selected values

for η and γ are 0.5 and 0.35, respectively. The

updation of weights is made in such a manner that the

mean square error (MSE) is reduced. At 𝑛𝑡ℎ sampling

instant, this is defined as,

where r is the length of input and output sequence.

The length of the input and output sequences for the

algorithm is [2×1]. The fundamental active power

weights (𝑤𝑝𝑎 , 𝑤𝑝𝑏 and 𝑤𝑝𝑐 ) corresponding to three

phase load currents are formulated by (4) as,

The average magnitude of weights ( 𝑤𝑝𝑎𝑣𝑔 )

corresponding to active power components

(𝑤𝑝𝑎,𝑤𝑝𝑏and 𝑤𝑝𝑐) is given as,

The total reference weight (𝑤𝑝 ) corresponding to

active power component is obtained by adding the

average weight (𝑤𝑝𝑎𝑣𝑔) and the DC bus PI controller

weight (𝑤𝑝𝑑𝑐) as

The reference currents ( 𝑖𝑝𝑎∗ , 𝑖𝑝𝑏

∗ and 𝑖𝑝𝑐∗ )

corresponding to fundamental active component are

computed by using (2) and (10) as,

These active reference grid currents are used to

compute total reference grid currents.

B. Computation of Fundamental Reactive

Components of Reference Grid Currents

Using Echo-State Network:-

The unit quadrature vectors of PCC voltages are

calculated from unit in-phase templates (𝑢𝑝𝑎, 𝑢𝑝𝑏and

𝑢𝑝𝑐) as,

The voltage regulation using SAPF is performed by

means of an additional PI controller realized over the

peak of PCC voltage (𝑉𝑡 ). The error between the

actual and the desired peak voltage is passed through

a PI controller and output (wt) is computed at 𝑛𝑡ℎ

sampling instant as,

where 𝐾𝑝𝑞 and 𝐾𝑖𝑞 represent gains of this PI

controller.



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The reactive weights (𝑊𝑞𝑎, 𝑊𝑞𝑏and 𝑊𝑞𝑐) from non-

sinusoidal load currents are computed by using (4) as,

The average weight (𝑊𝑞𝑎𝑣𝑔) of reactive constituent is

calculated from the amplitude of load reactive weight

components (𝑊𝑞𝑎, 𝑊𝑞𝑏and 𝑊𝑞𝑐) as,

The reference reactive constituent (𝑊𝑞) is computed

by subtracting average weight (𝑊𝑞𝑎𝑣𝑔) from output of

AC bus PI controller (𝑊𝑡 ). Here, wt is used to

compensate for the voltage drop due to grid

impedance and loading on the system as,

Reference currents of fundamental reactive power

component are calculated using unit quadrature

templates given in (12) to (14) and reference reactive

weight given by (20) as,

These fundamental reactive components are utilized

with fundamental active components given by (11) to

generate references given as follows.

C. Computation of References and Gating

Pulses:-

The addition of active (𝑖𝑝𝑎∗ , 𝑖𝑝𝑏

∗ and 𝑖𝑝𝑐∗ ) and reactive

( 𝑖𝑞𝑎∗ , 𝑖𝑞𝑏

∗ and 𝑖𝑞𝑐∗ ) components of reference grid

currents using (11) and (21) gives total reference grid

currents (𝑖𝑠𝑎∗ , 𝑖𝑠𝑏

∗ and 𝑖𝑠𝑐∗ ) as,

The grid currents are sensed and compared with

these reference grid currents, and the current errors

(isae, isbe and isce) are generated which are passed

over PWM current controller. Thus, appropriate

gating pulses are generated for the SAPF.

Fig. 2 Controller based on echo-state network for shunt active filter

Simulation results by using fuzzy

controller: Fuzzy rule is a sort of many-regarded justification in

which reality estimations of elements may be any

bona fide number some place in the scope of 0 and 1.

By separate, in Boolean method of reasoning, reality

estimations of components may simply be 0 or 1.

Fluffy basis has been contacted manage the

possibility of partial truth, where reality regard may

go between absolutely apparent and completely false.



ISSN NO:2236-6124

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Moreover, when semantic factors are utilized, these

degrees might be overseen by particular capacities.

Membership function for error in input-1

Membership function for change in error input-2

Membership function for output

The 3 variables of the FLC, the mistake, the alternate

in error and the output, have 7 triangle membership

features for each. The fundamental fuzzy units of

membership features for the variables are as proven

inside the Figs.8. The fuzzy factors are

communicated by semantic factors „positive

enormous (PB)‟, ‟, „positive little (PS)‟, „zero (Z)‟,

„negative little (NS)‟,‟, „negative huge (NB)‟, for

every one of the three factors.A lead inside the

govern base can be communicated in the shape: If (e

is NB) and (de is NB), at that factor (album is Z). The

tenets are set in view of the facts of the framework

and the operating of the framework. The administer

base alters the obligation cycle for the PWM of the

inverter as in keeping with the modifications within

the contribution of the FLC. The amount of ideas can

be set as desired. The quantities of guidelines are 49

for the 7 enrollment elements of the blunder and the

adjustment in mistake (contributions of the FLC).

Input/

output

NB NM NS ZE PS PM PB

NB NB NB NB NB NM NS ZE

NM NB NB NB NM NS ZE PS

NS NB NB NM NS ZE PS PM

ZE NB NM NS ZE PS PM PB

PS NM NS ZE PS PM PB PB

PM NS ZE PS PM PB PB PB

PB ZE PS PM PB PB PB PB

TABLE: FUZZY RULES

SIMULATION RESULTS:

FIG:3.aBehaviour of intermediate signals for echo

state network controller



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FIG:3.bBehaviour of intermediate signals for echo


FIG: 4Behaviour shunt filter in PFC mode

FIG:5Harmonic spectra of phase a of PCC

voltage,vsa

FIG: 6Harmonic spectra of phase a of supply

current,Isa

FIG :7Harmonic spectra of phase a of load current

,Iia in phase mode

FIG: 8Load current THD

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

-10

-5

0

5

10

Selected signal: 25 cycles. FFT window (in red): 3 cycles

Time (s)

0 100 200 300 400 500 600 700 800 900 10000

2

4

6

8

10

12

Frequency (Hz)

Fundamental (50Hz) = 15.02 , THD= 12.40%

Mag (

% o

f F

undam

enta

l)



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Page No:1399

FIG: 9Source current THD

FIG: 10Source voltage THD

FUZZY CONTROLLER:

Fig: 11 Behavior of intermediate signals for echo


Fig: 12 Behavior of intermediate signals for echo


FIG:13Behaviour shunt filter in PFC mode

Fig: 14 Harmonic spectra of phase a of PCC

voltage,vsa

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

-5

0

5

10


Time (s)

0 100 200 300 400 500 600 700 800 900 10000

0.2

0.4

0.6

0.8

1

Frequency (Hz)


Mag (

% o

f F

undam

enta

l)

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-500

0

500Selected signal: 25 cycles. FFT window (in red): 3 cycles

Time (s)

0 100 200 300 400 500 600 700 800 900 10000

0.2

0.4

0.6

0.8

1

1.2

Frequency (Hz)


Mag (

% o

f F

undam

enta

l)



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Fig: 15 Harmonic spectra of phase a of supply

current, Isa

Fig:16Harmonic spectra of phase a of load current

,IIa in phase mode

FIG: 17 load current THD

FIG:18 source current THD

FIG: 19 source voltage THD

THD

parameters

PI controller Fuzzy

controller

Source

current

1.06 0.45

Load current 12.40 10.12

Source

voltage

1.25 0.10

VI. CONCLUSION:-

The echo-state network algorithmic program has

been applied for the control of SAPF. This filter has

been used for load compensation and rising power

issue, reducing lower order harmonics and

reconciliation of three-phase load. These aforesaid

power quality issues are relieved with SAPF

operation in 2 completely different modes viz. PFC

and VR. The proposed management technique has

been found appropriate for extracting basic active and

reactive weights components from the distorted load

currents. the benefits of this management algorithmic

program are determined in terms of simplicity to

implement on DSP, improved harmonic

compensation, quick weight convergence and fewer

machin burden, when put next to SRFT and LMS

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

-10

-5

0

5

10


Time (s)

0 100 200 300 400 500 600 700 800 900 10000

2

4

6

8

10

Frequency (Hz)


Mag (

% o

f F

undam

enta

l)

0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-10

-5

0

5

10


Time (s)

0 100 200 300 400 500 600 700 800 900 10000

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

Frequency (Hz)


Mag (

% o

f F

undam

enta

l)

0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-500

0

500Selected signal: 25 cycles. FFT window (in red): 3 cycles

Time (s)

0 100 200 300 400 500 600 700 800 900 10000

0.005

0.01

0.015

Frequency (Hz)

Fundamental (50Hz) = 441 , THD= 0.10%

Mag (

% o

f F

undam

enta

l)



ISSN NO:2236-6124

Page No:1401

based mostly management algorithms. it's offered

less machine burden (45µs) in real time

implementation on the processor. in depth results

have been bestowed very well along side the

intermediate signals. These results highlight the

satisfactory performance of SAPF exploitation echo

state network based mostly management algorithmic

program below a variety of load conditions as well as

load unbalancing of the severest kind once one

section of the load is changed. Experimental

validation of the algorithmic program has been

achieved and the results show a three.8% doctor's

degree in grid current when compensation, that may

be a substantial improvement from 21.4% doctor's

degree in load current, thereby meeting limits such

that in AN IEEE 519 customary.

REFERENCES:-

[1] B. Singh, A. Chandra, and K. Al-Haddad, Power

quality: problems and mitigation techniques, John

Wiley & Sons Ltd., U.K, 2015.

[2] A. Ghosh and G. Ledwich, Power quality

enhancement using custom power devices, Springer

International Edition, Delhi, 2009.

[3] B. Singh, K. Al-Haddad and A. Chandra, “A

review of active filters for power quality

improvement,” IEEE Trans. Ind. Electron., vol. 46,

no. 5, pp. 960-971, Oct 1999.

[4] C. Lascu, L. Asiminoaei, I. Boldea and F.

Blaabjerg, “High Performance Current Controller for

Selective Harmonic Compensation in Active Power

Filters,” IEEE Trans. Power Electron., vol. 22, no. 5,

pp. 1826-1835, Sept. 2007.

[5] H. Akagi, Y. Kanazawa and A. Nabae,

“Instantaneous reactive power compensators

comprising switching devices without energy storage

components” IEEE Trans. Ind. Applications, vol. 20,

no. 3, pp. 625- 630, May/June 1984.

[6] B.N. Singh, B. Singh, A. Chandra and K. Al-

Haddad, “Design and digital implementation of

active filter with power balance theory,” IEE Proc.-

Electr. Power Appl., vol. 152, no. 5, Sep. 2005, pp.

1149-1160.

[7] U.K. Rao, M.K. Mishra and A. Ghosh, “Control

strategies for load compensation using instantaneous

symmetrical component theory under different supply

voltages,” IEEE Trans. Power Del., vol. 23, pp. 2310-

2317, 2008.

[8] C. H. da Silva, R. R. Pereira, L. E. B. da Silva, G.

Lambert-Torres and B. K. Bose, “Improving the

dynamic response of shunt active power filter using

modified Synchronous Reference Frame PLL,” in

Proc. 34th Annual Conference of IEEE Industrial

Electronics, 2008, pp. 790-795.

[9] Simon S. Haykin, Adaptive Filter Theory, Person

Education India, 2008.

[10] B. Singh, S. R. Arya, A. Chandra and K. Al-

Haddad, “Implementation of adaptive filter in

distribution static compensator,” IEEE Trans. Ind.

Applications, vol. 50, no. 5, pp. 3026-3036, Sept.-

Oct. 2014.



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