economic operation of autonomous ac, dc and hybrid ac/dc...

Economic Operation of Autonomous AC, DC and Hybrid AC/DC

Micro-grids by using Fuzzy logic controller Chinthaginjala Obul Kumar 1 M. Purushotham 2

1 PG Student / Department of Electrical Electronics Engineering,

Shree Institute of Technical Education, Tirupathi A.P. India

2 Assistant Professor / Department of Electrical Electronics Engineering,

Shree Institute of Technical Education, Tirupathi, A.P. India

ABSTRACT:

Financial activity is a noteworthy worry for micro-grids (MGs). Framework activity cost is enhanced when

the incremental costs (ICs) of every single disseminated generator (DGs) achieve fairness. Traditionally, monetary

dispatches of DGs are fathomed by brought together control with improvement calculations or conveyed control

with agreement calculations. To enhance the unwavering quality, adaptability also, economy of MGs, a completely

decentralized monetary power sharing procedure is proposed in this paper. As recurrence is a worldwide state in AC

MG and DC transport voltage fills in as a characteristic marker in DC MG, a recurrence IC (f-IC) hang plot is

proposed for Air conditioning MG, a voltage-IC (V-IC) hang conspire is proposed for DC MG and a standardization

conspire is proposed for half and half AC/DC MG. By utilizing the proposed system, ICs of DGs achieve balance

with the merging of the framework worldwide pointer (recurrence or DC transport voltage). At that point control

sharing of every DG is consequently accomplished in view of its important IC work and the aggregate working cost

can be improved with no correspondence or focal controllers. The proposed approach is executed in an AC MG, a

DC MG and a crossover AC/DC MG in Mat lab/Simulink to check its adequacy.

Index Terms-- Economic operation, incremental cost, power-sharing, decentralized, autonomous micro-grids

INTRODUCTION:

Dispersed generators (DGs) are increasing

developing consideration due to their monetary,

natural and supportable impetuses. DGs incorporate

breeze vitality sources, sun powered PV sources,

energy units, micro turbines, and so on. Micro-grid

(MG), which consolidates DGs, vitality stockpiles

(ESs) and a group of burdens, is a key innovation

empowering the use of DGs. MGs can be named AC

MG, DC MG and half and half AC/DC MG .

Numerous inquires about have been engaged on AC

MG improvement as ordinary power frameworks

have overwhelmingly embraced AC because of its

favorable circumstances in control transmission,

dispersion and change. On the other hand, numerous

DGs, for example, sun oriented PV and FC, and most

vitality stockpiles are DC sources by nature.

Additionally, there is an expanding number of DC

loads incorporated to the lattice including light-

transmitting diode (LED), correspondence and

computation gadgets, engine drive frameworks, and

so on. This prompts the motivating forces for creating

DC MG as it gives an effective coordination with the

decrease of intensity change stages. Thinking about

the upsides of AC MG and DC MG, cross breed

AC/DC MG has been proposed and pulls in

developing interests as of late. In a cross breed

AC/DC MG, Air conditioning and DC perfect units

are associated with AC and DC sub-grids fittingly

and the two sub-grids are tied by interlinking

converters.

MG has two activity modes: network

associated mode and independent mode . In network

associated mode, the recurrence furthermore, voltage

of MG are overwhelmingly controlled by the primary

brace. In independent task, without the help from

primary matrix, recurrence and voltage ought to be

kept up by DGs and the control of MG is frequently

more unpredictable because of the little latency of

independent MG. Legitimate control plans ought to

be intended to guarantee solid and temperate task of

MG. As different DGs have distinctive working cost

attributes, it is fundamental to perform financial

dispatch to improve framework working expense.

Routinely, monetary dispatch of DGs is an

enhancement issue to limit add up to working

expense and is regularly understood by a

concentrated controller with improvement

calculations, for example, Lagrangian unwinding

system, quadratic programming , hereditary

International Journal of Research

Volume 7, Issue XII, December/2018

ISSN NO:2236-6124

Page No:1284

calculation, self-sorting out various leveled molecule

swam streamlining, and so on. These concentrated

control plans have points of interest of high exactness

and controllability. Notwithstanding, they experience

high correspondence furthermore, calculation

troubles and may endure single point-of failure

issues. Also considering the appropriated nature of

MGs and the usage of attachment and play

innovation, incorporated control plan won't not be

monetarily suitable, particularly for islanded MGs in

remote zone. In dispersed control systems with

accord calculations are proposed to take care of the

monetary dispatch issue with expanded unwavering

quality and adaptability. Incremental cost of each DG

is chosen as the agreement variable and ideal power

order of every DG is created by just imparting with

neighboring DGs. Be that as it may, correspondences

still remain among various DGs and the execution of

agreement calculation is regularly confused. To

additionally build framework unwavering quality,

adaptability and economy, a completely decentralized

control ought to be produced and this is the focal

point of this paper.

Hang control strategies are the for the most

part embraced decentralized control strategies. In AC

MG, control sharing among DGs is performed by

dynamic power-recurrence (P-f) and receptive control

voltage (Q-V) hang attributes with just local

measurements. In DC MG, as the DC transport

voltage can be seen as a worldwide pointer, the

power-voltage (P-V) hang conspire is executed for

relative power sharing [9]. In crossover AC/DC MG,

a standardization conspire with P-f hang control for

AC subgrid and P-V hang control for DC sub grid is

proposed for self-sufficient power sharing among all

DGs all through the two sub grids . Numerous altered

hang control techniques have been proposed to

enhance framework execution For instance, a

dynamic hang pick up is proposed in to moist the

power motions; A versatile hang pick up plot is

proposed in [24] to remunerate voltage drop and

increment receptive power sharing precision; To

bargain with nonlinear load and uneven load, a

negative-succession impedance controller and a

symphonious impedance controller are proposed,

separately. Be that as it may, for all these hang based

strategies, dynamic power sharing among DGs

depends on their kVA evaluations and little

consideration is paid on their task cost. As financial

activity is a noteworthy control objective, working

expense ought to be considered for control sharing

also. Cost based hang plans are proposed by altering

hang coefficients as per the age cost qualities. In spite

of the fact that the working expense is spared

contrasted and regular hang control, the ideal cost

sparing can't be ensured amid the full activity extend.

In this paper, an incremental cost (IC) based hang

control system is proposed to improve working

expense in a decentralized way and it is actualized for

self-sufficient AC, DC what's more, cross breed

AC/DC MGs. For AC MG, as the recurrence is a

worldwide express, a recurrence incremental cost (f-

IC) hang trademark is proposed and actualized for all

DGs. At that point ICs of all DGs can way to deal

with fairness consequently went with by the

synchronization of frequencies of all DGs at enduring

state. The power dispatch for every DG is as

indicated by applicable IC capacity and framework

works at the ideal point. Essentially for DC MG, as

the DC transport voltage fills in as the worldwide

pointer, a voltage-incremental cost (V-IC) hang

trademark is proposed. For half breed AC/DC MG, a

standardization plot with the proposed f-IC and V-IC

hang attributes is executed. By this implies, ICs of

DGs can be upheld to a normal esteem self-

sufficiently and add up to working expense of the

MG can be advanced without the contribution of any

correspondence.

This paper is composed as takes after: Section II

presents customary hang control plans for AC, DC

and half and half Air conditioning/DC MGs. In

Section III, an IC based hang control system is

proposed, including f-IC hang conspire for AC MG,

V-IC hang conspire for DC MG and a standardization

plot for half and half AC/DC MG. Recreations are

directed in Mat lab/Simulink to approve the adequacy

of the proposed procedure in Section IV. Conclusions

are attracted Section V.

II. AUTONOMOUS MGS WITH

CONVENTIONAL DROOP

CONTROL

Fig. 1. Schematic diagram of an autonomous AC

MG.



ISSN NO:2236-6124

Page No:1285

Fig. 2. Schematic diagram of an autonomous DC

MG.

Fig. 3. Schematic diagram of an autonomous

hybrid AC/DC MG.

Bidirectional interlinking converter (BIC).

For the activity of self-governing-MGs-,hang control

plans are generally embraced what's more, will be

quickly-presented beneath.

A. Conventional droop control

in AC MG

As indicated by regular hang control conspire,

dynamic what's more, responsive intensity of one DG

can be controlled by P-f hang plan and Q-V hang

plot, communicated as

𝑓𝑖 = 𝑓𝑚𝑎𝑥 − 𝑚𝑖𝑃𝑖 (1)

𝑉𝑖 = 𝑉𝑚𝑎𝑥 − 𝑛𝑖𝑄𝑖 (2)

Where fmax and 𝑉𝑚𝑎𝑥 are the most extreme

recurrence and voltage sufficiency at no heap

condition; mi and ni are hang coefficients of ith DG

in light of the most extreme deviations of recurrence

also, voltage size and the important age limit as

portrayed in.

𝑚𝑖 = 𝑓𝑚𝑎𝑥 − 𝑓𝑚𝑖𝑛

𝑃𝑖,𝑚𝑎𝑥

𝑛𝑖 = 𝑉𝑚𝑎𝑥− 𝑉𝑚𝑖𝑛

𝑄𝑖,𝑚𝑎𝑥 (3)

As frequencies are implemented to be equivalent for

all DGs at relentless state, dynamic power produced

by every DG can be portrayed by

𝑃𝑖 = 𝑓𝑚𝑎𝑥− 𝑓

𝑚𝑖 (4)

Where f is the framework basic recurrence at

relentless state.

B. Conventional droop control in DC

MG

The traditional hang procedure in AC MG can be

broadened to DC MG by supplanting the P-f hang

with the P-V hang, given by

𝑉𝑑𝑐−𝑗 = 𝑉𝑑𝑐−𝑚𝑎𝑥 − 𝑑𝑗𝑃𝑗 (5)

where 𝑉𝑑𝑐_𝑗 is the terminal voltage of the jth

DG, 𝑉𝑑𝑐, 𝑚𝑎𝑥 is the most extreme DC transport

voltage at no heap condition, dj is hang

coefficient of 𝑗𝑡ℎ DG in view of the greatest

reasonable DC transport voltage deviation and

the pertinent age limit of the 𝑗𝑡ℎ DG, which is

given by

𝑑𝑗 = 𝑉𝑑𝑐,𝑚𝑎𝑥−𝑉𝑑𝑐,𝑚𝑖𝑛

𝑃𝑗,𝑚𝑎𝑥 (6)

At that point control created by every DG can be

portrayed by

𝑃𝑗 = 𝑉𝑑𝑐,𝑚𝑎𝑥−𝑉𝑑𝑐,

𝑑𝑗 (7)

Where 𝑉𝑑𝑐 is the DC bus voltage at steady state.

It ought to be said that, in view of the

diverse line impedance amongst DGs and normal

DC transport, control sharing among DGs may

marginally veer off from the coveted esteem. This

minor mistake is like that accomplished by

receptive power partaking in AC MG and has been

broadly talked about in writings. To enhance the

power sharing precision, strategies presented in can

be received and this won't be additionally talked

about here as it isn't the focal point of this paper.

C. Conventional droop control

in hybrid AC/DC MG

It ought to be said that, in view of the diverse line

impedance amongst DGs and normal DC transport,

control sharing among DGs may marginally veer off

from the coveted esteem. This minor mistake is like

that accomplished by receptive power partaking in

AC MG and has been broadly talked about in

writings. To enhance the power sharing precision,

strategies presented in can be received and this won't



ISSN NO:2236-6124

Page No:1286

be additionally talked about here as it isn't the focal

point of this paper.

∑ ` (1

𝑚𝑖) (𝑓𝑚𝑖𝑛 − 𝑓)𝑛

𝑖=1 = ∑ 𝑃𝑎𝑐_𝑖𝑛𝑖=1 (8)

where Pac i is the output power of ith DG in AC sub

grid Manipulating (8) yields an overall P-f droop for

AC subgrid:

(9)

where meq is the equivalent droop coefficient for all u

DGs in AC subgrid, expressed as

(10)

Similarly, an overall P-V droop for DC sub grid is

obtained by summing both sides of eqn. (7) and

doing manipulation as

(11)

where Pdc_j is the yield intensity of jth DG in DC

subgrid and deq is the proportional hang coefficient

for all v DGs in DC subgrid, given by

(12)

To consolidate the hang plans of two sub-grids,

recurrence extend [fmin, fmax] and voltage run

[𝑉𝑑𝑐, 𝑚𝑖𝑛, 𝑉𝑑𝑐, 𝑚𝑎𝑥] are standardized to a typical

per-unit go at [-1, 1] by the standardization recipe:

At the point when the standardized recurrence

𝑓𝑝𝑢 and voltage 𝑉𝑑𝑐, 𝑝𝑢 are evened out, the two sub-

grids could share control in light of their evaluations.

A basic path is to bolster the distinction of f_pu and

Vdc,pu to a PI controller to create dynamic power

reference for BIC.

Customary hang control plans presented above can

accomplish self-sufficient power sharing among DGs

in light of their control evaluations with no

correspondence. In any case, as different sorts of

DGs have distinctive cost attributes, monetary task

ought to be thought about. To improve the framework

working cost, an incremental cost (IC) based hang

control system is proposed and will be shown in the

following area.

III. PROPOSED IC-BASED

DROOP CONTROL STRATEGY

Age expenses of various dispatch-able DGs (diesel

generators, power modules, batteries, and so on.)

incorporate numerous elements, yet in general, they

can be spoken to by a quadratic capacity, given by

(13)

Where ai0, ai1 and ai2 are cost coefficients of the ith

DG.

For a MG with n DGs, the goal of monetary

task is to limit the aggregate working cost, which is

given by. Equity limitation is the power adjust

necessity portrayed by and imbalance requirement is

the age limit confinement of every DG given by .

This is the same as the regular financial dispatch

issue in control framework.

(14)

According to conventional Lagrangian

relaxation technique

Fig. 4. Proposed frequency-IC droop scheme.

expecting power appraisals of all DGs are not abused,

at the point when every DG has the same incremental

cost (IC), framework working expense is advanced.

The IC of ith DG is characterized as the subordinate

of its cost work, given by

(15)

At the point when the ICs of all DGs

achieve uniformity, framework works at the ideal



ISSN NO:2236-6124

Page No:1287

point. To get the ideal point, advancement

calculations are actualized in brought together control

strategies and agreement calculations are led in

conveyed control strategies, all of which require

correspondences as said already. To wipe out

correspondence also, enhance unwavering quality

and adaptability, a decentralized procedure for

financial dispatch is proposed in this paper. As there

are worldwide states in MGs which will be upheld to

uniformity for all DGs self-governing at relentless

state, for example, recurrence in AC MG and DC

transport voltage in DC MG, by choosing an

appropriate worldwide state as the framework marker

and relating IC with it, the meeting of ICs will wind

up self-governing. This is the essential thought of the

proposed IC based hang control technique and it will

be nitty gritty in AC MG, DC MG and crossover

AC/DC MG as howl.

A. Proposed frequency-IC droop

control strategy In AC MG, recurrence is a worldwide state and

ought to be kept up the same for all DGs at enduring

state. Then again, the ICs of all DGs should unite to

be equivalent at the ideal working point. On the off

chance that a relationship of recurrence and IC is

built up, the union of ICs can be accomplished with

the synchronization of recurrence.

As indicated by P-f hang relationship in (1) and IC

cost work in (18), recurrence and IC are directly

related. At that point a recurrence IC (f-IC) hang

trademark can be set up as

(16)

where mIC is the hang coefficient which ought to be

the same for all DGs and it is given by (20) thinking

about the requirements of intensity limit and most

extreme recurrence deviation.

(17)

where Imax is the maximum IC of all the DGs, i.e.

(18)

Delineates how the financial power sharing

between two DGs can be accomplished under the

proposed f-IC droop scheme. DG1 and DG2 are

coordinated to the basic AC transport to nourish stack

PD and the power adjust relationship in (22) is

continuously kept up. The IC elements of the DGs

are appeared in the left piece of Fig. 4 and the

proposed f-IC trademark is appeared in the correct

part. Accept DG1 gives P1 and DG2 gives P2 before

unfaltering state and the relating ICs are IC1 and IC2.

It can be seen from the f-IC hang relationship that

frequencies of DG1 framework and DG2 framework

are f1 also, f2, and f2< f1. To authorize a similar

recurrence, DG1 increments control supply and DG2

diminishes control supply. The balance point is

accomplished when DG1 and DG2 come to a basic

recurrence with the power supply of P1_o and P2_o

separately. Now, ICs of DGs are evened out at ICo

and along these lines the balance point is the ideal

point with limited framework working expense.

(19)

In light of the f-IC hang conspire, IC at the ideal

point ICo can be gotten as (23) and the relating ideal

power supply of ith DG is dictated by (24) as per its

significant IC work in (18). By utilizing the proposed

f-IC hang plot, monetary activity of AC MG is

acknowledged without interchanges.

B. Proposed voltage-IC droop

control strategy

In DC MG, DC transport voltage fills in as a

worldwide pointer. Like the proposed f-IC hang

plot for AC MG, a relationship of DC transport

voltage and IC can be set up for DC MG and it is

proposed as voltage-IC (V-IC) hang conspire,

given by

(20)

where dIC is a typical hang coefficient for all

DGs in DC MG and it is given by (26) thinking

about the limitations of intensity limit and most

extreme transport voltage deviation.

(21)

With the proposed V-IC hang control plot, when

theterminal voltages of DGs are evened out, ICs

can unite to an ideal esteem self-governingly.

Fig. 5 demonstrates the execution of the

proposed procedure in a DC MG with DG1 and

DG2.



ISSN NO:2236-6124

Page No:1288

Fig. 5. Proposed voltage-IC droop scheme

Fig. 6. Normalized f-IC droop and V-IC droop

scheme.

En-couraging burden PD. The power adjust

relationship is the same as (22) and ought to be kept

up constantly. Accept DG1 supplies P1 and DG2

supplies P2 before enduring state. In light of IC cost

bends of DGs and the V-IC hang attributes, the

terminal voltages of DG1 and DG2 are V1 and V2.

As V1 is bigger than V2, DG1 will supply more

power and DG2 will diminish its capacity age until

the point that V1 is equivalent to V2 at the harmony

point Vo. Now, two DGs have a similar IC esteem

ICo and in this manner the framework working

expense is limited. The IC esteem ICo is given by

(27) in light of the proposed V-IC hang attributes and

the ideal power age of ith DG can be communicated

as (24). Upon the usage of the proposed system,

decentralized monetary dispatch in DC MG is

accomplished.

(22)

C. Normalization scheme for

hybrid AC/DC MG The proposed f-IC hang control in

(19) and V-IC hang control in (25) can be

connected for monetary activity of AC MG

and DC MG separately. For crossover

AC/DC MG, the control methodology in AC

subgrid and DC subgrid will be the same as

that in AC MG and DC MG, and power

sharing for monetary activity in each subgrid

can be accomplished exclusively. At that

point the bidirectional interlinking inverter

(BIC) in AC furthermore, DC is executed to

oversee control stream between AC what's

more, DC sub-grids for general ideal power

sharing. To organize the two sub-grids, the

two hang plans ought to be combined. The

standardization procedure in (13) will be

received with the goal that f-IC hang and V-

IC hang can be set together with basic

vertical and flat tomahawks. Upon the

execution of standardization system,

recurrence go is standardized to [-1, 1] and

the standardized f-IC hang plan can be

communicated as.

(23)

where mIC,pu is the coefficient for

standardized f-IC hang technique which

ought to be the same for all DGs in AC

subgrid and like (20), it is given by

(24)

where ICmax is the same as the articulation in

(18). Correspondingly, the standardized V-

IC hang plot is communicated as

(25)

where dIC,pu is the coefficient for

standardized V-IC hang methodology which

ought to be the same for all DGs in DC

subgrid and is given by

(26)

It can be seen from (28) and (30)

that the standardized f- IC hang plan and V-

IC hang plot are indistinguishable with a

similar coefficient. Fig. 6 represents the

power sharing procedure for monetary

activity of half breed AC/DC framework. As

of now talked about in Section III.A and

III.B, ICs of all DGs in Air conditioning

subgrid are balanced when frequencies of

DGs are synchronized to a typical esteem f

at consistent state; ICs everything being

equal in DC sub grid are evened out when

terminal voltages of DGs unite to be

equivalent at Vdc at relentless state. The

interlinking converter will control the power

stream amongst AC and DC subgrids to

uphold f_pu = Vdc,pu. With the leveling of

standardized recurrence and DC transport

voltage, ICs all things considered. all

through two sub-grids can be evened out and

monetary power sharing between two sub-

grids can be accomplished. Like Area II.C, a

straightforward PI controller can be utilized



ISSN NO:2236-6124

Page No:1289

for BIC reference control age to authorize

the condition.

D. Some other considerations:

1) Stochastic characteristics of

renewable energy sources

sources As the incremental cost of sustainable

power sources (RESs) can be viewed as zero, to

enhance monetary advantage, the RESs are

ordinarily work at most extreme power point

following mode. Hence, they are non-dispatch able

circulated ages (DGs) and can be viewed as steady

power sources. In this paper, as the concentration is

the monetary activity of the dispatch able DGs, the

RESs are viewed as consistent power sources also,

they are joined with the lumped stack, filling in as

the identical heap of the dispatch able DGs. The

stochastic attributes of the sustainable power

sources will cause the variety of yield intensity of

the dispatch able DGs. In any case, with the usage

of the proposed IC-based technique, the financial

task can at present be accomplished.

2) Implementation with higher

level control with communication As the proposed technique is completely

decentralized, it can be executed at the essential

level of the progressive control structures and work

with numerous more elevated amount control

systems for example, auxiliary recurrence

rebuilding, voltage reclamation and unequal voltage

pay to accomplish more capacities.

3) Reactive power sharing and

unbalanced situations

For monetary task, the working expense depends on

dynamic control age and the cost of responsive

power age is typically disregarded . In this manner,

responsive power sharing and voltage size control

are not considered in the proposed technique, and

the generally utilized regular Q-V hang plot in (2)

will be embraced. The proposed technique centers

around monetary task under typical conditions,

though it is adaptable to join with other novel

strategies to manage nonlinear or unequal load

conditions. For instance, the negative-grouping yield

impedance controller proposed in can be utilized

with the proposed strategy to manage the unequal

conditions and the symphonious impedance

controller proposed in can be actualized to manage

the nonlinear load conditions.

4) Stability analysis

As the proposed methodology is directly in light of

traditional hang methodology, strength examination

is like that with the execution of regular hang

control and can be alluded to a few literary works,

for example for AC MG,for DC MG andfor half

breed ACDC MG. By supplanting the customary

hang models with the proposed hang models in

these investigations, framework soundness under the

proposed method can be examined and appropriate

parameters can be chosen to guarantee stable

activity.

5) Radial connection case

It merits specifying that heaps and DGs in a down to

earth MG are typically associated in various hubs

(transports) of an outspreadarrange rather than a

typical PCC. For this situation, the proposed

technique can even now be utilized for DGs in spiral

associated AC MG as the proposed f-IC hang plot

depends on framework recurrence, which won't be

influenced by the line impedance be between

distinctive transports. For DC outspread system, the

line obstruction between DGs must be considered,

as the proposed VIC hang plot depends on the

normal transport voltage like regular P-V hang

technique and will experience the same

disadvantage of wrong power sharing when line

impedance can't be disregarded. A few

methodologies have been proposed to increment the

power sharing precision for regular hang control in

DC coordinate with line impedance and can

additionally be actualized in the proposed strategy.

In this way, the propose strategy is additionally

appropriate to spiral associated MGs.

With the execution of the proposed IC based hang

control technique, ICs of all DGs can join to be

equivalent self-rulingly what's more, framework

working expense is in this manner upgraded. It

ought to be specified that if at the coveted balance

point, the ideal power age of one DG achieves its

upper/ bring down bound, it will be set at its

upper/bring down bound esteem what's more, the

rest of the DGs will share the rest control under the

proposed IC based hang control.

Fuzzy logic

Fuzzy logic is a form of many-valued logic in which

the truth values of variables may be any real number

between 0 and 1. By contrast, in Boolean logic, the

truth values of variables may only be 0 or 1. Fuzzy

logic has been extended to handle the concept of

partial truth, where the truth value may range

between completely true and completely



ISSN NO:2236-6124

Page No:1290

false. Furthermore, when linguistic variables are

used, these degrees may be managed by specific

functions.

Usually fuzzy logic control system is created from

four major elements presented on Figure

Fuzzification interface, fuzzy inference engine, fuzzy

rule matrix and Defuzzification interface. Each part

along with basic fuzzy logic operations will be

described in more detail below.

Fig. 7. The fuzzy logic analysis and control methods

shown in Figure 1 can be described as:

1. Receiving one or large number of

measurements or other assessment of

conditions existing in some system that will

be analyzed or controlled.

2. Processing all received inputs according to

human based, fuzzy ”if-then” rules, which

can be expressed in simple language words,

and combined with traditional non-fuzzy

processing.

3. Averaging and weighting the results from all

the individual rules into one single output

decision or signal which decides what to do

or tells a controlled system what to do. The

result output signal is a precise defuzzified

value.

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.

Moreover, when semantic factors are utilized, these

degrees might be overseen by particular capacities.

Fig.8 Membership function of input-1

Fig. 9 Membership function of input-2

Fig. 10 Membership function of output

The three variables of the FLC, the error, the change

in error and the output, have five triangle

membership functions for each. The basic fuzzy sets

of membership functions for the variables are as

shown in 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 in the govern

base can be communicated in the shape: If (e is NB)

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

are set in view of the information of the framework

and the working of the framework. The administer

base alters the obligation cycle for the PWM of the

inverter as per the adjustments in the contribution of

the FLC. The quantity of principles can be set as

wanted. The quantities of guidelines are 25 for the

five enrollment elements of the blunder and the

adjustment in mistake (contributions of the FLC).

Input/output NB NS ZE PS PB

NB ZE ZE PB PB PB

NS ZE ZE PS PS PS

ZE PS ZE ZE ZE NS

PS NS NS ZE ZE ZE

PB NB NB NB ZE ZE

Table: 1 fuzzy table



ISSN NO:2236-6124

Page No:1291

4. Simulation results

6.1 Ac micro grid:

6.1.1 Conventional:

(a)

(b)

(c)

(d)

(e)

6.1 AC GRID GRAPHS AT CONVENTIONAL a.

cost, b. frequency, c. power, d. total cost, e.

voltage.

6.1.2 PI controller:

A

B

C



ISSN NO:2236-6124

Page No:1292

D

E

6.2 AC GRID GRAPHS AT PI CONTROLLER

A. Cost, B. frequency, C. power, D. total cost, E.

voltage.

6.2 DC micro grid:

6.2.1 Conventional:

A

B

C

6.3 DC GRID AT CONVENTIONAL A. Cost, B.

power, C. total cost

6.2.2 PI controller:

A

B

c

D

6.4 DC GRID AT PI controller cost, power, total

cost, dc voltage



ISSN NO:2236-6124

Page No:1293

6.3 DC GRID AT STOHASTIC

CHARACTERISTICS OF RES:

6.3.1 PI CONTROLLER:

A

B

C

D

6.5 DC GRID AT STOHASTIC

CHARACTERISTICS A. cost, B. load power, C.

power, and D. dc voltage

6.4 DC GRID SECONDARY

VOLTAGE RESTORATION

CONTROL:

6.4.1 PI CONTROLLER:

A

B

C

6.6 DC GRID SECONDARY VOLTAGE

RESTORATION CONTROL A. Cost, B. dc

voltage, C. power

6.5 DC-AC-DC MG:

6.5.1 CONVENTIONAL:

A



ISSN NO:2236-6124

Page No:1294

B

C

D

6.6 DC-AC-DC MG AT CONVENTIONAL A.

Cost, B. frequency, C. power, D. total cost

6.5.2 DC-AC-DC MG PI

CONTROLLER:

A

B

C

D

E

F

G



ISSN NO:2236-6124

Page No:1295

H

6.7 DC-AC-DC MG PI CONTROLLER A. IC

COST, B. IT THD, C. POWER, D. T COST, E.

VOLTAGE, F. VT THD, G. AC VT, H. AC

FREQUENCY

6.6SIMULATION RESULTS

USING FUZZY CONTROLLER:

A

B

C

D

E

F

G

H

E

6.8:A.COST fuzzy controller, B. IT THD,

C. NORMALZED, D. POWER, E. TCOST, F.

VAC, G. VDC, H. VF, E. VTTHD



ISSN NO:2236-6124

Page No:1296

Parameter PI controller Fuzzy

control

Current THD 9.78% 3.22%

Voltage THD 8.66% 3.45%

Fig. 6.1 Thd values

Conclusion

In this paper, an IC based hang control procedure

has been proposed for decentralized financial

dispatch in self-ruling Air conditioning, DC and

crossover AC/DC MGs. As recurrence is a

worldwide state in AC MG and DC transport voltage

is a characteristic marker in DC MG, a f-IC hang

procedure is proposed for AC MG, a VIC hang plot is

proposed for DC MG and a standardization plot with

the proposed f-IC and V-IC is proposed for half and

half Air conditioning/DC MG. As the worldwide

variable (framework recurrence or DC transport

voltage) will be implemented to a typical incentive at

unfaltering state self-sufficiently, IC of every DG

achieves correspondence and framework for control

partaking in AC MG, DC MG and half and half Air

conditioning/DC MG are led in Matlab/Simulink to

approve the adequacy of the proposed procedure. The

proposed system gives a straightforward, solid and

adaptable answer for monetary activity of MGs.

References

[1] F. Blaabjerg, R. Teodorescu, M. Liserre, and A.

V. Timbus, “Overviewof control and grid

synchronization for distributed power

generationsystems,” IEEE Trans. Ind. Electron., vol.

53, no. 5, pp. 1398–1409,2006.

[2] D. E. Olivares, A. Mehrizi-Sani, A. H. Etemadi,

C. a. Cañizares, R.Iravani, M.Kazerani, A. H.

Hajimiragha, O. Gomis-Bellmunt, M.Saeedifard, R.

Palma-Behnke, G. a. Jiménez-Estévez, and N.

D.Hatziargyriou, “Trends in microgrid control,”

IEEE Trans. Smart Grid,

vol. 5, no. 4, pp. 1905–1919, 2014.

[3] J. M. Guerrero, P. C. Loh, T.-L. Lee, and M.

Chandorkar, “Advanced control architectures for

intelligent microgrids—Part II: Power quality,energy

storage, and AC/DC microgrids,” IEEE Trans. Ind.

Electron.,vol. 60, no. 4, pp. 1263–1270, 2013.

[4] X. Liu, P. Wang, and P. C. Loh, “A hybrid

AC/DC microgrid and itscoordination control,” IEEE

Trans. Smart Grid, vol. 2, no. 2, pp. 278–286, 2011.

[5] D. De and V. Ramanarayanan, “Decentralized

parallel operation ofinverters sharing unbalanced and

nonlinear loads,” IEEE Trans. PowerElectron., vol.

25, no. 12, pp. 3015 3025, 2010.

[6] J. M. Guerrero, M. Chandorkar, T. Lee, and P. C.

Loh, “AdvancedControl Architectures for Intelligent

Microgrids-Part I: Decentralizedand Hierarchical

Control,” Ind. Electron. IEEE Trans., vol. 60, no. 4,

pp.1254–1262, 2013.

[7] H. Karimi, E. J. Davison, and R. Iravani,

“Multivariable servomechanismcontroller for

autonomous operation of a distributed generation

unit: Design and performance evaluation,” IEEE

Transactions on Power Systems, vol. 25, no. 2, pp.

853–865, 2010.

[8] J. Xiao, P. Wang, and L. Setyawan, “Hierarchical

Control of Hybrid Energy Storage System in DC

Microgrids,” Industrial Electronics, IEEE

Transactions on, vol. 62, no. 8. pp. 4915–4924, 2015.

[9] T. Dragicevic, X. Lu, J. Vasquez, and J. Guerrero,

“DC Microgrids-PartI: A Review of Control

Strategies and Stabilization Techniques,” IEEETrans.

Power Electron., vol. 8993, no. c, pp. 1–1, 2015.

[10] J. Xiao, P. Wang, L. Setyawan, and Q. Xu,

“Multi-Level Energy Management System for Real-

Time Scheduling of DC Microgrids With Multiple

Slack Terminals,” IEEE Trans. Energy Convers., vol.

31, no. 1, pp. 392–400, Mar. 2016.



ISSN NO:2236-6124

Page No:1297

economic operation of autonomous ac, dc and hybrid ac/dc...

Documents