a novel control method for transformerless h bridge cascaded statcom with excellent dyna

International Journal of Research in Advanced Technology - IJORAT Vol. 2, Issue 3, MARCH 2016

All Rights Reserved © 2016 IJORAT 1

A NOVEL CONTROL METHOD FOR

TRANSFORMERLESS H BRIDGE

CASCADED STATCOM WITH

EXCELLENT DYNAMIC

PERFORMANCE Liza.V

1, S.Nirosha Devi

2, S.Usha Rani

3

123Student, Dept of EEE ,FRANCIS XAVIER ENGINEERING COLLEGE, Tamilnadu, India

ABSTRACT:This work proposes a novel technique in transformerless STATCOM design based on the H-

Bridge converter star topology. The proposed method jointly implementing current control loops and also

the DC voltage control loops. The current control loops and also the DC voltage control loops are

designed based on the four parts like passivity based control, overall voltage control, Clustered balancing

control,. Individual balancing control. The current loop control, a non linear controller based on the

passivity based control theory is used in this cascaded structure STATCOM for the first time. The dc

capacitor voltage control ,overall voltage control is realized by adopting proportional resonant (PR)

controller. Clustered balancing control is obtained by using active disturbances rejection controller

(ADRC). Individual balancing control is achieved by shifting the modulation wave vertically which can be

easily implemented in FPGA .The proposed system is providing good dynamic performance while

compared with the conventional STATCOM topology because of its robust procedure.

KEYWORDS :PR-Proportional Resonant, ADRC-Active Disturbances Rejection Controller

I. INTRODUCTION

Power Generation and Transmission is a

complex process, requiring the working of many

components of the power system in tandem to

maximize the output. One of the main components

to form a major part is the reactive power in the

system. It is required to maintain the voltage to

deliver the active power through the lines. Loads

like motor loads and other loads require reactive

power for their operation. To improve the

performance of ac power systems, we need to

manage this reactive power in an efficient way and

this is known as reactive power compensation.

There are two aspects to the problem of reactive

power compensation: load compensation and

voltage support. Load compensation consists of

improvement in power factor, balancing of real

power drawn from the supply, better voltage

regulation, etc. of large fluctuating loads. Voltage

support consists of reduction of voltage fluctuation

at a given terminal of the transmission line. Two

types of compensation can be used: series and

shunt compensation. These modify the parameters

of the system to give enhanced VAR compensation.

In recent years, static VAR compensators like the

STATCOM have been developed. These quite

satisfactorily do the job of absorbing or generating

reactive power with a faster time response and

come under Flexible AC Transmission Systems

(FACTS). This allows an increase in transfer of

apparent power through a transmission line, and

much better stability by the adjustment of

parameters that govern the power system i.e.

current, voltage, phase angle, frequency and

impedance.



As power demand increases in many parts

of the world , power transmission needs to be

developed, as well. The FACTS devices are used in

power system to enhance the system utilization,

power transfer capacity and power quality for ac

system interconnections, STATCOM is utilized at

the point of common connection to absorb or inject

the required reactive power, through which the

voltage quality of PCC is improved. Now a days

many topologies are used in the STATCOM. One

of the topology is H-bridge cascaded STATCOM

has been widely used in high power applications.

The H –bridge STATCOM leads to following

applications like high efficiency, quick response

speed, small volume, minimal interaction with the

supply grid and individual phase control ability.

II. PROPOSED SYSTEM

A.BLOCK DIAGRAM

The below block diagram shows the

control algorithm for H – bridge cascaded

STATCOM . The whole control algorithm mainly

consist of parts , namely ,passivity based control,

overall voltage control, clustered balancing control.

The three parts are achieved in DSP. The current

loop control, a non linear controller based on the

passivity based control theory is used in this

cascaded structure STATCOM for the first time.

The dc capacitor voltage control ,overall voltage

control is realized by adopting proportional

resonant (PR) controller. Clustered balancing

control is obtained by using active disturbances

rejection controller (ADRC).

Fig 1: Control block diagram for the 10 KV 2

MVA H-bridge cascaded STATCOM

.

B. PWM GENERATOR

The PWM Generator block generates

pulses for carrier-based pulse width modulation

(PWM) converters using two-level topology. The

block can be used to fire the forced-commutated

devices (FETs, GTOs, or IGBTs) of single-phase,

two-phase, three-phase, two-level bridges or a

combination of two three-phase bridges.The pulses

are generated by comparing a triangular carrier

waveform to a reference modulating signal. The

modulating signals can be generated by the PWM

generator itself, or they can be a vector of external

signals connected at the input of the block. One

reference signal is needed to generate the pulses for

a single- or a two-arm bridge, and three reference

signals are needed to generate the pulses for a

three-phase, single or double bridge.

The amplitude (modulation), phase, and

frequency of the reference signals are set to control

the output voltage (on the AC terminals) of the

bridge connected to the PWM Generator block.

Pulse width modulation (PWM) is a method of

changing the duration of a pulse with respect to the

analog input. The duty cycle of a square wave is



modulated to encode a specific analog signal level.

This pulse width modulation tutorial gives you the

basic principle of generation of a PWM signal. The

PWM signal is digital because at any given instant

of time, the full DC supply is either ON or OFF

completely.PWM method is commonly used for

speed controlling of fans, motors, lights, pulse

width modulation controller etc. These signals may

also be used in varying intensities for approximate

time-varying of analogue signals. Below you can

see the pulse width modulation generator circuit

diagram (pulse width modulator) using op amp.

PWM is employed in a wide variety of

applications, ranging from measurement and

communications to power control and conversion.

C. PASSIVITY BASED CONTROL

To better understand the passivity concept

and passivity-based control (PBC), we need to

leave behind the notion of state of a system and

think of the latter as a device which interacts with

its environment by transforming inputs into

outputs. From an energetic viewpoint we can define

a passive system as a system which cannot store

more energy than is supplied by some “source”,

with the difference between stored energy and

supplied energy, being the dissipated energy.

Passivity is a fundamental property of

many physical systems which may be roughly

defined in terms of energy dissipation and

transformation. It is an inherent Input-Output

property in the sense that it quantifies and qualifies

the energy balance of a system when stimulated by

external inputs to generate some output. Passivity

is therefore related to the property of stability in an

input-output sense, that is, we say that the system is

stable if bounded “input energy” supplied to the

system, yields bounded output energy. This is in

contrast to Lyapunov stability which concerns the

internal stability of a system, that is, how “far” the

state of a system is from a desired value. In other

words, how differently a system behaves with

respect to a desired performance

Passivity based control is a methodology which

consists in controlling a system with the aim at

making the closed loop system, passive. A section

is also devoted to a wide class of physical

passive systems: the Euler-Lagrange (EL) systems

and their passivity-based control.

Figure 2: Block diagram of PBC

Consider the above figure the following set of

voltage and current equations can be derived:

𝐿 𝑑𝑖𝑎𝑑𝑡

= 𝑢𝑠𝑎 − 𝑢𝑎 − 𝑅𝑖𝑎 − − − − − (3.1)

𝐿 𝑑𝑖𝑏𝑑𝑡

= 𝑢𝑠𝑏 − 𝑢𝑏 − 𝑅𝑖𝑏 − − − − − −(3.2)

𝐿 𝑑𝑖𝑐𝑑𝑡

= 𝑢𝑠𝑐 − 𝑢𝑐 − 𝑅𝑖𝑐 − − − − − −(3.3)

Where R is the equivalent series resistance

of the inductor.

Applying the d-q transformations ,the equations in

d-q axix are obtained

𝐿 𝑑𝑖𝑑𝑑𝑡

= −𝑅𝑖𝑑 + 𝜔𝐿𝑖𝑞 + 𝑢𝑠𝑑 − 𝑢𝑑 − − − (3.4)

𝐿 𝑑𝑖𝑞

𝑑𝑡= −𝜔𝐿𝑖𝑑−𝑅𝑖𝑞 + 𝑢𝑠𝑞 − 𝑢𝑞 − − − (3.5)

Where ud and uq are d-axis and q axis

components corresponding to the three-phase

STATCOM cluster voltages, ua,ub and uc. Usd

and usq are those corresponding to the three- phase

grid voltages usa,usb and usc. Whenthe grid

voltages are sinusoidal and balanced , usq is always

zero because usa is aligned with d-axis.



To apply PBC method the above equation

is transformed in to the form of EL, system model

in this paper. EL system model is one of the

important part of the non linear PBC theory and an

effective modelling technology. It defines the

energy equation by setting the general variable and

harness the known theorem that can be used to

analyses the dynamic performance to deduce the

dynamic equations.

D. OVERALL VOLTAGE CONTROL

As the first level control of the dc

capacitor voltage balancing, the aim of the overall

voltage control is to keep the dc mean voltage of all

converter cells equalling to the dc capacitor

reference voltage. The common approach is to

adopt the conventional PI controller which is

simple to implement. However, the output voltage

and current of H-bridge cascaded STATCOM are

the power frequency sinusoidal variables and the

output power is the double power frequency

sinusoidal variable, it will make the dc capacitor

also has the double power frequency ripple voltage.

So the reference current which is obtained in the

process of the overall voltage control is not a

standard dc variable and it also has the double

power frequency alternating component and it will

reduce the quality of STATCOM output current.

Figure 3: Block diagram of overall

voltage control.

To resolve the problem, this paper adopts

PR controller for the overall voltage control. The

gain of PR controller is infinite at the fundamental

frequency and very small at the other frequency.

Consequently, the system can achieve the zero

steady state error at the fundamental frequency. By

setting the

Cut off frequency and the resonant frequency of PR

controller appropriately, it can reduce the part of

ripple voltage in total error, decrease the reference

current distortion which is caused by ripple voltage

and improve the quality of STATCOM output

current. Moreover, the dynamic performance and

the dynamic response speed of the system also can

be improved. In particular, during the start up

process of STATCOM, the much larger dc voltage

overshoot can be restrained effectively.

PR controller is composed of a

proportional regulator and resonant regulator. Its

transfer function can be expressed as

Gpr s = kp +2kr ωc s

s2+2ωc s+ω02 ----------- (3.7)

where kp is the proportional gain coefficient. kr is

the integral gain coefficient. wc is the cutoff

frequency. Wo is the resonant frequency. Kr

influences the gain of the controller but the

bandwidth. With kr increasing, the amplitude at the

resonant frequency is also increased and it plays a

role in the elimination of the steady state error. wc

influences the gain of the controller and the

bandwidth. With wc increasing, the gain and the

bandwidth of the controller are both increased. This

paper selects kp=0.05, kr=10,wc=3.14 rad/s and

wo=100pie as the controller parameters.

E. CLUSTERED BALANCING CONTROL

The purpose of the clustered balancing

control is to keep the dc mean voltage of three

cascaded converter cells in each cluster equal to the

dc mean voltage of the three clusters. The clustered

balancing control as the second level control of the

dc capacitor voltage balancing , the purpose is to

keep the dc mean voltage of 12 cascaded converter

cells in each cluster equalling the dc mean voltage



of the three clusters. ADRC is adopted to achieve

it.

Figure 4: Block diagram of clustered

balancing control.

The block diagram of the

clustered balancing control with the simplified

ADRC. When ADRC receives the reference

voltage udc* and the real-time detected value of the

dc mean voltage ukdc ( k = a,b,c ) of 12 cascaded

converter cells in each cluster, it will trace the

reference voltage rapidly with TD and obtain the

tracking signal v1 by filtering. Then, by subtracting

the tracking signal v1 from the state estimation

signal of the dc capacitor voltage z1 , the control

deviation command €1 the system voltage is

calculated. €1 is used as the input signal of

NLSEF. Finally, the active adjustment control

current ▲ik ( k = a,b, c ) of the clusteredbalancing

control is achieved by subtracting the disturbance

estimate signals which obtained in ESO from the

output result of NLSEF.

F. INDIVIDUAL BALANCING CONTROL

The individual control becomes necessary

because of the different cells have different losses.

The aim of the individual balancing control as the

third level control is to keep each of 12 dc voltages

in the same cluster equalling to the dc mean voltage

of the corresponding cluster. It plays an important

role in balancing 12 dc mean capacitor voltages in

each cluster

Fig 5: Block Diagram of Individual Balancing

Control

Figure shows the block diagram of the

individual balancing dc-capacitor voltage control. It

forms an active power between the ac voltage of

each bridge cell and the corresponding cluster

current.

G. CIRCUIT DIAGRAM

Figure shows the circuit configuration of

the 10 kV 2 MVA star-configured STATCOM

cascading 12 H-bridge PWM converters in each

phase and it can be expanded easily according to

the requirement. By controlling the current of

STATCOM directly, it can absorb or provide the

required reactive current to achieve the purpose of

dynamic reactive current compensation.



Figure 6: Circuit diagram of the

experimental system.

The power switching devices working in ideal

condition is assumed. usa , usb and usc are the

three-phase voltage of grid. a u , b u and c u are the

three-phase voltage of STATCOM. isa ,isb and isc

are the three-phase current of grid. ia , ib and ic are

the three-phase current of STATCOM. ila , ilb and

ilc are the three-phase current of load. Udc is the

reference voltage of dc capacitor. C is the dc

capacitor. L is the inductor. Rs is the

H. SIMULATION OF PROPOSED SYSTEM

The proposed method describes most

widely used linear control schemes are PI

controllers. In to regulate reactive power, only a

simple PI controller is carried out. In through a

decoupled control strategy, the PI controller is

employed in a synchronous d–q frame. Thus, a

number of intelligent methods have been proposed

to adapt the PI controller gains such as particle

swarm optimization neural networks and artificial

immunity. A dc injection elimination method called

IDCF is proposed to build an extra feedback loop

for the dc component of the output current.

To verify the correctness and effectiveness

of the proposed methods, the experimental platform

is built according to the second part of this paper.

Two H-bridge cascaded STATCOMs are running

simultaneously. One generates the set reactive

current and the other generates the compensating

current that prevents the reactive current from

flowing into the grid. The experiment is divided

into two parts: the current loop control experiment

and the dc capacitor voltage balancing control

experiment. In current loop control experiment, the

measured experimental waveform is the current of

a-phase cluster and it is recorded by the

oscilloscope. In dc capacitor voltage balancing

control experiment, the value of dc capacitor

voltages are transferred into DSP by signal

acquisition system and they can be recorded and

observed by CCS software in computer. Finally,

with the exported experimental data from CCS,

experimental waveform is plotted by using

MATLAB.

With the proposed control method, the

reactive current is compensated effectively. The

error of the compensation is very small. The

residual current of the grid is also quite small. The

phase of the compensating current is basically the

same as the phase of the reactive current. The

waveforms of the compensating current and the

reactive current are smooth and they have the small

distortion and the great sinusoidal shape. When

STATCOM is running in over load state (about 1.4

times current rating), due to the selected IGBT has

been reserved the enough safety margin,

STATCOM still can run continuously

and steadily. The over load capability of

STATCOM is improved greatly and the operating

reliability of STATCOM in practical industrial

field is enhanced effectively.



Figure 7: Simulation model of proposed system.

I.SIMULATION RESULT

This chapter will investigate the results

of the proposed model. Simulated

results of the project are shown and

discussed.

Fig 8: Result for Real Power from

Genaration

The figure shows the simulation result

for power from generation

Fig 9:Result for Reactive Power from

Generation

This figure shous the simulation

result for reactive power from

generation.

Fig 10: Result for Real Power

from STATCOM

This above figure shows the

simulation result for Real Power

from STATCOM

2

V DC

1

PF Source PI

Vpcc

Vdc

Vabc

Vinv

Ipcc

Iabc

Iinv

Vpcc*

Vdc*

Vabc*

Vinv *

Ipcc*

Iabc*

Iinv *

fi lter concept

A

B

C

A

B

C

a

b

c

A

B

C

a

b

c

A B C

a b

c

A

B

C

a

b

c

A B C

A B C

out

Q f rom Gen

Q Demand at Load

P f rom Gen

P Demand at Load

PF at Source

PF at load

P f rom STATCOM

Q f rom StTATCOM

Subsystem3

In1

ANGLE

Conn4

Conn5

Conn6

Subsystem1

VPcc

V DC in

Subsystem

Statcom V & I3

Statcom V & I2

Reference2

Reference1

Real P From Gen

Real P Demand

Reactive Q drawn from Gen

Reactive Q Demand

Q STATCOM

PFat Load

PF at Source

P STATCOM

VDC

Goto1

Vabcc

Iinvv

Vinvv

Ipccc

VDCC

Vpcc

Iabc

RealPI

ReactivePI

Vdc2

From20

Vabc

Vdc1

From19

Vdc

From18

I_mul

V_mul

Vdc

From15

Vpcc

From14

Vpccc

Iabcc

I_inv

V_inv

Ipcc

VDC0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

0

0.5

1

1.5

2

Time(sec)

voltage(v

)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Time(sec)

voltage(v

)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-1.6

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

Time(sec)

voltage(v

)

source_power_factor



Fig 11: Result for Reactive

Power from STATCOM

This above figure shows the simulation

result for reactive power from

STATCOM

Fig 12 : Result for Real Power

Demand at Load

The above figure shows the

simulation result for real power

demand at load.

Fig 13 : Result for Reactive Power

Demand at Load


simulation result for reactive power

demand at load.

Fig 14 Result for Source Votage


simulation result for source voltage.

Fig 15: Result for source current

This above figure shows

the simulation result for source

current.

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

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

Time(sec)

voltage(v

)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50

0.05

0.1

0.15

0.2

0.25

Time(sec)

pow

er(w

)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50

0.05

0.1

0.15

0.2

0.25

time(sec)

pow

er(w

)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-1

-0.5

0

0.5

1

Time(sec)

voltage(v)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-1.5

-1

-0.5

0

0.5

1

1.5

Time(sec)

current(am

p)

source_power_factor



Fig 16 : Result for Load Voltage


the simulation result for load

voltage.

Fig 17: Result for Load Current


the simulation result for load

current.

Fig 18: Result for Inverter Voltage


simulation result for Inverter

Voltage.

Fig 19: Result for

Inverter current This above figure shows the simulation

result for inverter current.

Fig 20: Result for DC Voltage

This above figure shows the simulation

result for DC Voltage

Fig 21: Result for H Bridge

Cascaded Input Voltage

The above figure shows the

simulation result for H Bridge

Cascaded input voltage.

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-1

-0.5

0

0.5

1

Time(sec)

voltage(v)

source_power_factor

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

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

Time(sec)

current(am

p)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-1

-0.5

0

0.5

1

Time(sec)

voltage(v)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-1.5

-1

-0.5

0

0.5

1

1.5

Time(sec)

current(am

p)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50

200

400

600

800

1000

Time(sec)

voltage(v)

source_power_factor

0.475 0.48 0.485 0.49 0.495 0.5-1500

-1000

-500

0

500

1000

1500

Time(sec)

voltage(v

)



Fig 22: Result for Load Power

Factor

This figure shows the

simulation result for load power factor.

Fig 23: Result for Source Power

Factor


simulation result for source power

factor.

Fig 24: Resut for Total Harmonic

Distortion

CONCLUSION

This paper has addressed a

transformerless STATCOM model

based on multi level H bridge converter

with star topology. This paper has

analyzed the fundamentals of

STATCOM based on multilevel H-

bridge converter with star

configuration. And then, the actual H-

bridge cascaded STATCOM rated at 10

kV 2 MVA is constructed and the novel

control methods are also proposed in

detail. The proposed methods has the

following characteristics: A PBC

theory based nonlinear controller is

first used in STATCOM with this

cascaded structure for the current loop

control, and the viability is verified by

the experimental results. The PR

controller is designed for overall

voltage controland the experimental

result proves that it has better

performance in terms of response time

and damping profile compared with the

PI controller. The ADRC is first used

in H-bridge cascaded STATCOM for

clustered balancing control

and the experimental results verify that

it can realize excellent dynamic

compensation for the outside

disturbance.

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50.707

0.7071

0.7072

0.7073

0.7074

0.7075

Time(sec)

pow

er(w

)

source_power_factor

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50.942

0.944

0.946

0.948

0.95

0.952

0.954

0.956

0.958

Time(sec)

pow

er(w

)

source_power_factor



ACKNOWLEDGMENT

First of all we would like to thank the

almighty for giving me sound health

throughout my paper work. This research

was supported/partially supported by our

college. We thank our staffs from our

department who provided insight and

expertise that greatly assisted the research,

although they may not agree with all of the

interpretations/conclusions of this paper

REFERENCES

1. B. Gultekin, and M. Ermis, “Cascaded

Multilevel Converter-Based

Transmission STATCOM: System

Design Methodology and Development

of a 12 kV ±12 MVAr Power Stage,”

IEEE Trans. Power Electron., vol.28,

no.11, pp. 4930-4950, Nov. 2013.

2. B. Gultekin, C. O. Gerçek, T. Atalik,

M. Deniz, N. Biçer, M. Ermis, K.Kose,

C. Ermis, E. Koç, I. Çadirci, A. Açik,

Y. Akkaya, H. Toygar, and S.Bideci,

“Design and Implementation of a 154-

kV±50-Mvar Transmission STATCOM

Based on 21-Level Cascaded

Multilevel Converter,” IEEE Trans.

Ind. Appl. , vol. 48, no. 3, pp. 1030–

1045, May/June 2012

3. S. Kouro, M. Malinowski, K.

Gopakumar, L. G. Franquelo, J.

J.Rodriguez, B. Wu, M. A. Perez and J.

I. Leon, “Recent advances and

industrialapplications of multilevel

converters,” IEEE Trans. Ind Electron.

, vol. 57, no. 8, pp. 2553–2580, Aug.

2010.

4. C. H. Liu and Y. Y. Hsu, “Design of a

self-tuning PI controller for a

STATCOM using particle swarm

optimization,” IEEE Trans. Ind.

Electron. , vol. 57, no. 2, pp. 702–715,

Feb. 2010.

5. Y. O. Lee, Y. Han, and C. C. Chung,

“Output tracking control with enhanced

damping of internal dynamics and its

output boundedness,” in Proc. IEEE

Conf. Dec. Contr., 2010, pp. 3964–

3971.

6. Y. O. Lee, Y. Han, and C. C. Chung,

“Output tracking control with enhanced

damping of internal dynamics and its

output boundedness for STATCOM

system,” IET Contr. Theory Appl., vol.

6, no. 10, pp.1445–1455, 2012



7. L. Maharjan, S. Inoue, and H. Akagi,

“A Transformerless Energy Storage

System Based on a Cascade Multilevel

PWM Converter With Star

Configuration,” IEEE Trans. Ind.

Appl., vol. 44, no. 5, pp. 1621–1630,

Sep./Oct. 2008.

8. Y. Shi, B. Liu, and S. Duan,

“Eliminating DC Current Injection in

Current-Transformer-Sensed

STATCOMs,” IEEE Trans. Power

Electron., vol.28, no.8, pp.3760-3767,

Aug. 2013.

9. B. Singh, and S. R. Arya, “Adaptive

Theory-Based Improved Linear

Sinusoidal Tracer Control Algorithm

for DSTATCOM,” IEEE Trans. Power

Electron., vol.28, no.8, pp. 3768-3778,

Aug. 2013.

10. V. Spitsa, A. Alexandrovitz, and E.

Zeheb, “Design of a robusstate

feedback controller for a STATCOM

using a zero set concept IEEETrans.

Power Del vol. 25, no. 1, pp. 456–467,

Jan. 2010

11. C. D. Townsend, T. J. Summers, and R.

E. Betz, “Multigoal Heuristic Model

Predictive Control Technique Applied

to a Cascaded H-bridge StatCom,”

IEEE Trans. Power Electron., vol.27,

no.3, pp.1191-1200, March 2012.

12. C.D. Townsend, T. J. Summers, J.

Vodden, A. J. Watson, R. E. Betz, and

J. C. Clare, “Optimization of Switching

Losses and Capacitor Voltage Ripple

Using Model Predictive Control of a

Cascaded H-Bridge Multilevel

StatCom,” IEEE Trans. Power

Electron., vol.28, no.7, pp.3077-3087,

Jul. 2013.

13. H. Tsai, C. Chu and S. Lee, “Passivity-

based Nonlinear STATCOM Controller

Design for Improving Transient

Stability of Power Systems” presented

at IEEE/PES Transmission and

Distribution Conference & Exhibition:

Asia and Pacific, Dalian, China, 2005.

14. G. E. Valderrama, P. Mattavelli, and

A.M. Stankovic, “Reactive power and

unbalance compensation using

STATCOM with dissipativity-based

control,” IEEE Trans. Contr. Syst.

Technol., vol. 9, no. 5, pp. 718–727,

2001.



15. Q. Zheng, L. L. Dong, and Z. Gao,

“Control and rotation rate estimation of

vibrational MEMS gyroscopes ,” in

Proc. IEEE International Conference on

Control Applications, IEEE,

Piscataway, NJ, 2007, pp. 118–123.

16. W. Zhou and Z. Gao, “An active

disturbance rejection approach to

tension and velocity regu-lations in

Web processing lines ,” in Proc. IEEE

International Conference on Control

Applications, IEEE, Piscataway, NJ,

2007, pp. 842–848.

a novel control method for transformerless h bridge cascaded statcom with excellent dyna

Documents