epe_capacitor_voltage_control_techniques_of_the_z-source_inverter_a_comparative_study-libre.pdf

7/27/2019 EPE_Capacitor_Voltage_Control_Techniques_of_the_Z-source_Inverter_A_Comparative_Study-libre.pdf

1/12

Capacitor Voltage Control Techniques of the Z-source Inverter: A Comparative Study

EPE Journal Vol. 21 no 4 December 2011 13

Nomenclature

C1 = C2 = C Z-network capacitance (F)

Cos AC load power factor

D0 Steady state shoot-through duty ratio (%)

fcz Required gain cross over frequency (Hz)

Fs ZSI switching frequency (Hz)Gcv(s) Voltage loop controller T.F

Gci(s) Current loop controller T.F

Gid(s) Control to inductor current continuous T.F

Gid(z) Control to inductor current discrete T.F

Gii(s) Input to inductor current continuous T.F

GM(s) Modified modulation to shoot-through T.F

Gvd(s) Control to capacitor voltage continuous T.F

Gvd(z) Control to capacitor voltage discrete T.F

Gvi(s) Input to capacitor voltage continuous T.F

IL Steady state Z-network inductor current (A)

II Steady state equivalent DC load current (A)

iL, Vc,Il State variables: inductor current, capacitorvoltage and load current

~iL,

~Vc,

~Il Small signal perturbations in state variables

Ki Integral gain constant

Kp Proportional gain constant

L1 =L2 =L Z-network inductance (H)

Lac AC load phase inductance (H)

Ll Equivalent DC load inductance (H)

M Modulation index (%)

Rac AC load phase resistance ()Rl Equivalent DC load resistance ()Td Computation time delay (s)

Ti(s) Inner current loop gain

Tv(s) Outer voltage loop gain

Ts Sampling period (s)

Vc Steady state Z-network capacitor voltage (V)

Vin ZSI Input voltage (V)~vin,

~d0 Input voltage and shoot-through duty ratio small

signal perturbations

Vi Average DC-link voltage (V)Vip Peak DC-link voltage (V)

vm Modified modulation signal amplitude (V)

Vtri Triangle carrier signal amplitude (V)

Zac AC load phase impedance ()m Required phase margin ()

Introduction

The Z-source inverter (ZSI), as shown in Fig. 1, is an emergingtopology for power electronics DC-AC converters. It can utilizethe shoot-through (ST) state to boost the input voltage, which

improves the inverter reliability and enlarge its application field.In comparison with other power electronics converters, it providesan attractive single stage DC-AC conversion with buck-boostcapability, reduced cost, reduced volume and higher efficiency

Capacitor Voltage Control Techniques of the Z-source Inverter: A

Comparative Study

Omar Ellabban, R&D Department, Punch Powertrain, 3800 Sint-Truiden, Belgium

Joeri Van Mierlo, and Philippe Lataire, Department of Electrical Engineering and Energy Technology (ETEC), Vrije UniversiteitBrussel, 1050 Brussels, Belgium

Keywords: Z-source inverter, maximum constant boost control, small signal modeling, single-loop capacitor voltage control, dual-loopcapacitor voltage control

Abstract

The Z-source inverter (ZSI) is a recently proposed single-stage power conversion topology. It adds voltage boost capa-

bility for complementing the usual voltage buck operation of a traditional voltage source inverter (VSI) with improved

reliability. In this paper, a single-loop and dual-loop capacitor voltage control techniques for the ZSI are digitally

designed based on a third order small signal model of the ZSI, implemented using a digital signal processor (DSP) and

compared. Simulation and experimental results of a 30 kW ZSI during input voltage changes, load disturbances and

steady state operations are presented and compared. The results show that the dual-loop capacitor voltage control tech-

nique achieves better steady state and transient performance and enlarge the stability margins of the ZSI compared to

the single-loop capacitor voltage control technique.

Fig 1: The ZSI basic structure


2/12

Omar Ellabban, Joeri Van Mierlo, Philippe Lataire

due to a lower component number. For emerging power genera-tion technologies, such as fuel cells, photovoltaic arrays and windturbine, the ZSI is a very promising and competitive topology [1-3].

Since the ZSI was proposed in 2003 [4], lots of work had beendone in the ST control methods. Four different ST control methodshave been proposed in the literature, which are: simple boostcontrol (SBC) [4], maximum boost control (MBC) [5], maximum

constant boost control (MCBC) [6] and modified space vectormodulation boost control (MSVMBC) [7] methods. In [8], theauthors present a review of these four ST boost control methodsand present a comparison between them based on simulation andexperimental results. They concluded that the MCBC methodseems to be the most suitable boost control method for insertingthe ST state within the switching states of the ZSI. Therefore, theMCBC method will be used in this paper.

The control strategy of the ZSI is an important issue and severalfeedback control strategies have been investigated in recent publi-cations [9-24]. There are four methods for controlling the ZSI DC-link voltage, which are: capacitor voltage control [9-17], indirectDC-link voltage control [18, 19], direct DC-link control [20-22]and unified control [23, 24]. In [9-11], the capacitor voltage is

controlled by regulating the ST duty ratio using different controlmethods. Where, in [9] a PID controller is used to control the STduty ratio and the modulation index is set to beM= 1 D0 usingthe SBC method. While, in [10] a PI controller with saturation isused to control the ST duty ratio and a PI controller tuned by aneural network for wide range control is used in [11], where theMSVMBC method is used in [10-11]. In [12-14], nonlinear con-trol methods are used to control the capacitor voltage using theSBC method, where the gain scheduling combined with the statefeedback control was used in [12, 13] and sliding mode controlmethod was used in [14]. In [15-17], the capacitor voltage is con-trolled by the regulating the ST duty ratio and the output voltageis controlled by regulating the modulation index using the

MSVMBC method with two separate control loops with PI con-trollers as in [15, 16] and a neural network controllers as in [17].In [18], a PID-like fuzzy controller is used to indirectly control theaverage DC-link voltage using the SBC method, where the aver-age DC-link voltage is calculated by measuring the capacitor volt-age using the following relation Vi = Vc/(1 D0). Moreover, in[19], the peak DC-link voltage is indirectly controlled by control-ling the peak AC output voltage using a PI controller to regulate the

modulation index and the ST duty ratio is calculated by measur-ing the input voltage and comparing it by the required peak DC-link voltage using the MSVMBC method. In [20, 21], the peakDC link voltage is directly controlled by regulating the ST dutyratio, the peak DC-link voltage is measured using an additionalcircuit, because of its pulsating nature, which makes the controlalgorithm more complex, the SBC method was used in [20] andthe MSVMBC was used in [21]. In [22], the peak DC-link voltageis directly controlled by regulating the ST duty ratio using theSBC method, where the peak of the DC-link voltage was estimat-ed by measuring both the input and the capacitor voltages, as Vip= 2Vc Vin. In [23, 24], the unified control method is used to reg-ulate the modulation index and the ST simultaneously by control-ling the AC output voltage using a single PI controller using theMSVMBC method. Table 1, presents a review of the above men-

tioned control methods with their drawbacks.

In all the above mentioned control methods, a single-loop voltagecontrol technique was used. However, in high power converters, asingle-loop voltage control has two problems. The first problem isthat, the inductor current is not regulated and can be overloadedduring transient events and the limited stability limits is thesecond problem [25]. Therefore, a dual-loop voltage control is pre-ferred over a single-loop voltage control in high power convertersto overcome the above mentioned problems [26].

This paper presents, a comparative study between two capacitorvoltage control techniques for controlling the DC-link voltage of

EPE Journal Vol. 21 no 4 December 201114

Table 1 Review of previous ZSI control strategies

Reference No. Control method Controller type Controller variable Drawbacks

9 Vc control Single loop control with a PID D0 The controller is designed basedcontroller on a second order model

10 Vc control Single loop control with a PI D0 The controller is not designedcontroller with saturation

11 Vc control Single loop control with a D0 The controller parameters is tunedPI controller by neural network (NN)

12, 13 Vc control Single loop nonlinear control D0 andM Complex control algorithm

14 Vc control Single loop nonlinear control D0 Complex control algorithm

15, 16, 17 Vc control Two control loops with a PI controller D0 andM The controller is not designed ortuned by NN

18 Indirect Vi

PID fuzzy controller D0

The controller is not accurate,control by because the relation between andcontrolling Vac is not linear and the controller is

not designed

19 Indirect Vi PI controller with saturation M The ST is not controlled and thecontrol by controller is not designedcontrolling Vac

20 Direct Vi control Single loop PID controller D0 External complex sensing circuitand the controller is not designed

21 Direct Vi control Two control loops with a PI controller D0 andM External complex sensing circuitand the controller is not designed

22 Direct Vi control Dual loop Vi control, the outer voltage D0 A simplified representation of theloop has a PI controller and the inner 3-phase load of the ZSIcurrent loop has a P controller

23, 24 Unified control Single loop with a PI controller Vreffor the MSVM Suitable for isolated operationsand the controller is not designed


3/12


the ZSI, which are single-loop and dual-loop control techniques.A digital PI controller with anti-windup correction is used for bothcontrol techniques. The performance of both control techniques isverified and compared by simulation and experimental results of a30 kW ZSI with inductive load during input voltage changes, loaddisturbances and steady state operations.

A small signal model of the ZSI

Many methods for modeling power converters have been reportedin the literature [27, 28]. Among these methods, the state spaceaveraged small-signal modeling, which is the most widely used tomodel power converters. Therefore, an accurate small-signalmodel of the ZSI is needed, which gives not only a global but alsoa detailed view of system dynamics and provides guidelines forsystem controllers design since the required transfer functionscould be derived accordingly.

General operation of a ZSI can be illustrated by simplifying the ACside circuit by an equivalent RL load in parallel with a switch S2and the input diode D is represented by a switch S1, as shown inthe simplified circuit presented in Fig. 2. Where, Rl is calculatedbased on output power balance of the two circuits (Fig. 1 and Fig.

2) asRl = 8Zac/3cos andLl is determined so that the time con-stant of the DC load is the same as the AC load [12]. Two operationmodes involving two different circuit topologies can be identifiedin the ZSI operation as shown in Fig. 3. In Mode 1, Fig. 3-a, theenergy transferred from source to load is zero because the loadside and source side are decoupled by the ST state and the openstatus of S1. In Mode 2, Fig. 3-b, real energy transfer betweensource and load occurs.

Let us define the state variables (capacitor voltages and inductorcurrents in the network, and load current) as a vector,

(1)

Due to Z-network symmetry, iL1(t) = iL2(t) = iL(t) and vc1(t) =

vc2(t) = vc(t), therefore the system order reduced to a third ordersystem, with state variables: iL(t) = vc(t) and il(t) [29, 30]. Usingstate space averaging method, and performing small signal pertur-bation for a given operating point, one gets:

(2)

after its Laplace transformation, it becomes:

(3)

sLi s D v s D v s V V L c in C in( ) ( ) ( ) ( ) ( ) ( )= + + 2 1 1 20 0 dd s

sLv s D i s D i s I

0

0 01 2 1 2

( )

( ) ( ) ( ) ( ) ( ) ( c L l L= + ++

=

I d s

sLi s D v s R i s D

l

l c l l

) ( )

( ) ( ) ( ) ( ) (

0

02 1 1 00 02) ( ) ( ) ( ) v s V V d sin C in+ +

d

d

i t

v t

i t

D

L

D

t

L

c

l

( )

( )

( )

=

02 1

0

1 2

0

0

CC

D

C

D

L

R

L

01

02 1

0

0

( )

( )

l

l

l

i t

v t

i t

L

c

l

( )

( )

( )

( )

+

1

0

1

0D

L

D

L

v

E

l

in (( )t

V V

L

I I

C

V V

L

+

+

+

2

2

2

C in

L l

C in

l

d t0 ( )

x t i t i t v t v t i t( ) [ ( ) ( ) ( ) ( ) ( )]= L1 L2 c1 c2 lT

The steady state values can be calculated by Ax + Bu = 0, as:

(4)

In small-signal modeling and transient analysis, the response ofone state variable to multiple small-signal perturbations can beexpressed as a linear combination of the variable response to eachindividual perturbation. The capacitor voltage and the inductorcurrent can be expressed as a linear combination of the variableresponse to each individual perturbation as:

(5)

where Gvd(s), Gvi(s), Gid(s) and Gii(s) are given by:

v s G s d s G s v s

i s G s

c vd vi in

L id

( ) ( ) ( ) ( ) ( )

( ) ( )

= +

=0

dd s G s v s0 ( ) ( ) ( )+ ii in

VD

DV

ID

DI

IV

R

Co

in

Lo

l

lC

l

=

=

=

1

1 2

1

1 2

0

0


Fig. 2: A simplified equivalent circuit for the ZSI

Fig. 3: The basic two equivalent operation modes:(a) ST state, (b) NST state


4/12


Predicting the right half plane (RHP) zeros of the related transferfunctions is one of the major advantages of the small-signal mode-ling. By considering the control-to-capacitor voltage transfer

function, given by Eq. 6 as an example, the numerator is aquadratic equation. As known, for a quadratic equation ax2 + bx+c = 0, there will be two different poles and if the discrimi-nant b2 - 4ac > 0. Regarding this case, it can be acquired thata = ( 2IL +II)LIL < 0 and c = (1 2D0)(2Vc Vin)RI > 0, there-fore, this transfer function has two zeros: one is negative while theother is a positive one, which is called RHP zero. This identifies anon-minimum phase characteristic in the capacitor voltageresponse that is known to potentially introduce stability issuesin the closed loop regulated system. The design of a feedbackcontroller with an adequate phase margin becomes more difficultwhen RHP zeros appear in the transfer function, since it tends todestabilize the wide-bandwidth feedback loops, implying high-gain instability and imposing control limitations [29, 30].

Capacitor voltage control strategies

In order to conduct a fair comparison between the single-loop anddual-loop capacitor voltage control strategies of the ZSI, theymust be designed using the same procedure. The direct digitaldesign method is used to design the single and the dual-loop con-trollers, using the following steps: first, the continuous time con-trol to outputs transfers functions (Gvd(s) and Gid(s)) of the ZSI arediscretized using the zero order hold (ZOH) method. After that,once the discrete transfer functions of the system areavailable, the digital controllers are designed directlyin the z-domain using methods similar to the continu-ous time frequency response methods [31]. This hasthe advantage that the poles and zeros of the digitalcontrollers are located directly in the z-domain, result-

ing in a better load transient response, as well as betterphase margin and bandwidth for the closed loop powerconverter [32].

Single-loop capacitor voltage control

Fig. 4 shows the entire digital single-loop capacitorvoltage control technique of the ZSI containing thevoltage loop controller, Gcv(z), the zero order hold,(1 eTsS/s), the computational delay, eTds, the controlto capacitor voltage continuous time transfer functionGvd(s) and the modified modulation to ST transferfunction GM(s). Where GM(s) is expressed by [9]:

(10)G sD s

v s VM

m tri( )

( )

( )= =02

In this digital implementation the chosen sampling scheme resultsin a computation delay of half the sampling period (Td = Ts/2). Theloop gain for the single loop capacitor voltage control can be

expressed by [31]:

(11)

In this paper, a digital PI controller with anti-windup will bedesigned based on the required phase margin, and critical fre-quency, using the bode diagram of the system in the z-domain, thetransfer function of the digital PI controller in z-domain is givenby:

(12)

where

(13)

(14)K

f

G zi

cz

p

= sin( )

KG z

p

p

= cos( )

G z KK T z

zc p

i s( ) = +1

G z Ze

se G s G svd

-T s-T s

M vd

s

d( ) ( ) ( )=

1


Fig. 4: Single-loop capacitor voltage control: (a) system diagram,(b) discrete time block diagram

(a)

(b)

(6)

(7)

(8)

(9)G sD L LCs D D R Ls D

iil l( )

( ) ( )( ) (=

+ + 1 1 1 2 102

0 0 0 ))

[ ( ) ( ) ]

2

3 20

20

22 1 2 1

L

L LCs R LCs L D L D s Rl l l+ + + + ll D( )2 102

G sV V L Cs R C V V DC l C

idin l in( )

( ) [ ( ) ( )=

+ + 2 2 1 22 0 (( ) ] ( )( ) ( )( + + + 2 1 2 1 2 20 0I I L s D V V D ICL l l in L+++ + +

I R

L LCs R LCs L D L D

l l

l l l

)

[ ( ) ( ) ]3 2 02

022 1 2 1 ss R D+ l ( )2 10

2

G sD L D D L s D

vil( )

[( ) ( )( ) ] ( )(=

+ + 1 1 1 2 1 102

0 0 0 + + +

2

2 1 2 1

03 2

02

02

D R

L LCs R LCs L D L D

)

[ ( ) ( )

l

l l l ]] ( )s R D+ l 2 102

G sI I L Ls I I R L D

vdL l l L l l( )

( ) [( ) ( )(=

+ + + + 2 2 12 0 22 1 2 2 1 2 20 0V V L D V V L s D V C in c in l c + + ) ( )( ) ] ( )( + + +

V R

L LCs R LCs L D L D

in l

l l l

)

[ ( ) ( )3 2

02

02

2 1 2 1 ]] ( )s R D+ l 2 102


5/12


and

(15)

Dual-loop capacitor voltage control

Fig. 5 shows the entire dual-loop capacitor voltage control tech-nique of the ZSI containing the voltage loop and current loop con-trollers Gcv(s), Gci(s), the zero order hold, the computationaldelay, the control to outputs transfer functions Gvd(s), Gid(s) andthe modified modulation to ST transfer function GM(s), respec-tively. The loop gains for inner current loop and outer voltage loopcan be expressed as:

(16)

(17)

where the discretized inductor current to control transfer functionis given by:

(18)

As an example, Fig. 6 shows the bode plots for the current loopgain and voltage loop gain for the dual-loop control technique,

G z Ze

se G s G sid

-T s-T s

M id

s

d( ) ( ) ( )=

1

T zG z G z G z

T zv

cv ci vd

i

( )( ) ( ) ( )

( )=

+1

T z G z G zi ci id( ) ( ) ( )=

= + 180 m pG z( )

respectively, with the system parameters listed in Table2. The plots indicate that the current loop gain has acrossover frequency as high as 1 kHz, with a phasemargin of 65 and a gain margin of 10 dB. To avoidinteraction between the sub-systems, low control band-width is used for the voltage loop. The resulting outervoltage loop has a crossover frequency of 100 Hz anda phase margin of 59 and a gain margin of 25 dB.

Simulation and experimental results

The dynamic performance of the ZSI with single-loopand dual-loop capacitor voltage control techniques hasbeen tested using MATLAB simulation and experi-mental verification using the system parameters inTable 2. A 30 kW ZSI prototype, as shown in Fig. 7,has been designed, implemented and tested up to 10kW. The eZdsp F2808 evaluation board is used forthe realization of the capacitor voltage control tech-niques and the real time workshop (RTW) is used forautomatic code generation.


Fig. 5: Dual-loop capacitor voltage control: (a) system diagram,(b) discrete time block diagram

(a)

(b)

Fig. 6: Bode diagrams for current (a) and voltage (b) loops ofdual-loop capacitor voltage control

Fig. 7: Experimental setup of a 30 kW ZSI

(a)

(b)

Table 2: Experimental and simulation parameters of the ZSIParameter Value

Input voltage 200 V

Capacitor reference voltage 300 V

Inductance 650 HInductance internal resistance 0.22 Capacitance 320 FCapacitance internal resistance 0.9 mSwitching frequency 10 kHz

AC load inductance 340HAC load resistance 12.5


6/12


Figs. 8-10 show the simulation and experimental results of the sin-gle-loop capacitor voltage control technique and Figs. 11-13 showthe simulation and experimental results of the dual-loop capacitorvoltage control technique during input voltage step down by 7.5%with the same load, load increasing and decreasing by 50% andsteady state operations. It is noticeable that the experimentalresults in both cases match the simulation results very well.

By comparing Fig. 8 with Fig. 11, in case of input voltage stepdown, one can conclude that there is a noticeable oscillations in

the inductor current and the output line voltage in case of thesingle-loop control technique. Furthermore, during load distur-bances, Fig. 9 and Fig. 12, the single-loop control strategy,compared to the dual-loop control strategy, suffers from largeoscillations in the inductor current, capacitor voltage, DC-linkvoltage and output line voltage during load increasing by 50%. Inaddition, by comparing Fig. 10 and Fig. 13, the dual-loop controlstrategy gives better steady state performance compared with thesingle-loop control strategy. Therefore, the dual loop capacitorvoltage control technique achieves better steady state and transientperformances.

As well-know, the zeros in the RHP of the s-domain will bemapped outside the unity circle in the z-domain. Also, as the gainof a closed loop controlled system is increased, the root locus

position of the open loop system poles track towards the open loopsystem zeros. Since the control to capacitor voltage transfer func-

tion, Eq. 6, has a zero in the RHP, this means that attempting tocontrol the capacitor voltage with a single PI voltage controllerwill cause the open loop poles to track across the unity circle inthe z-domain into the RHP as the controller gain is increased, thusmaking the system unstable, as indicated in Fig. 14-a. In contrast,the control to inductor current transfer function given by Eq. 8contain only a left hand plane (LHP) zeros and consequently donot has a non-minimum phase characteristic. Controlling the ZSIinductor current with a closed loop PI controller makes the systemclosed loop poles track to the open loop system zeros, but in this

case their path is away from the unity circle and towards the ori-gin of the z-domain. When the outer voltage controller is wrappedaround the current controlled system, the RHP zero reappears inthe overall system transfer function, Eq. 17, and will cause thecurrent controlled system poles to once again track to the RHP asthe outer loop PI gain is increased. However, the pole locations ofthe cascaded system at the system final design gains are still insidethe unity circle, as shown in Fig. 14-b. Therefore, the insertion ofthe inner PI current control loop has modified the primary systemresponse to make it over damped and more stable. This hasallowed the gains of the outer PI voltage control loop to then beincreased to achieve a good overall system dynamic response,while still avoiding the stability limits of the single-loop voltagecontrol system.


(a)

(c)

(b)

(d)

Fig. 8: ZSI response during input voltage step down by 7.5 %: (a and c) simulation results and (b and d) experimental results usingsingle-loop control technique


7/12

Conclusion

This paper presents two techniques for digitally control the capa-citor voltage of the ZSI. Both control techniques are designedbased on a small-signal mode of the ZSI using a bode diagram ofthe discrete time transfer functions of the system to achieve therequired phase margin and critical frequency. Experimental andsimulation results of a 30 kW ZSI during input voltage changes,load disturbances and steady state for both single and dual-loopcontrol techniques are presented and compared. In addition, the

stability of both control techniques is discussed. Finally, the dual-loop capacitor voltage control technique achieves better steadystate and transient performance and more stable behavior com-pared to the single-loop capacitor voltage control technique.

References

[1] M. Shen, A. Joseph, J. Wang, F. Z. Peng and D. J. Adams:Comparison of Traditional Inverters and Z-Source Inverter for FuelCell Vehicles, IEEE Transactions on Power Electronics, vol. 22,no. 4, pp. 1453-1463, July 2007.

[2] Yi Huang, Miaosen Shen and Fang Z. Peng: Z-Source Inverter forResidential Photovoltaic Systems, IEEE Transactions on Power

Electronics, Vol. 21, No. 6, pp. 1776-1782, November 2006.[3] W.-T. Franke, M. Mohr and F. W. Fuchs: Comparison of a Z-


Source Inverter and a Voltage-Source Inverter Linked with aDC/DC Boost-Converter for Wind Turbines Concerning TheirEfficiency and Installed Semiconductor Power, IEEE 39th PowerElectronics Specialists Conference, PESC08, 15-19 June 2008.

[4] F. Z. Peng: Z-source inverter, IEEE Transactions on IndustryApplications, Vol. 39, No. 2, pp. 504-510, Mar/Apr. 2003.

[5] F. Z. Peng, M. Shen, and Z. Qian: Maximum boost control of theZ-source inverter, IEEE Transactions on Power Electronic,Vol. 20,No. 4, pp. 833-838. July 2005.

[6] Miaosen Shen, Jin Wang, A. Joseph, Fang Zheng Peng,L.M.Tolbert and D. J. Adams: Constant boost control of the Z-source inverter to minimize current ripple and voltage stress, IEEETransactions on Industry Applications, Vol. 42, No. 3, pp: 770-778,May-June 2006.

[7] Poh Chiang Loh, D. Mahinda Vilathgamuwa, Yue Sen Lai, GeokTin Chua and Yunwei Li: Pulse-Width Modulation of Z-SourceInverters, IEEE Transactions on Power Electronics, vol. 20, no. 6,November 2005.

[8] Omar Ellabban, Joeri Van Mierlo, and Philippe Lataire:Experimental Study of the Shoot-Through Boost Control Methodsfor the Z-Source Inverter, the European Power Electronics Journal(EPE J), Vol. 21, No. 2, pp. 18-29, June 2011.

[9] Ding, Xinping Qian, Zhaoming Yang, Shuitao Cui, Bin Peng,

Fangzheng: A PID Control Strategy for DC-link Boost Voltage inZ-source Inverter, The Twenty Second Annual IEEE Applied


(a)

(c)

(b)

(d)

Fig. 9: ZSI response during load increasing and decreasing by 50 % : (a and c) simulation results and (b and d) experimentalresults using single-loop control technique


8/12



(a)

(c)

(e)

(b)

(d)

(f)

Fig. 10: Steady state response of the ZSI : (a, c and e) simulation results and (b, d and f) experimental result using single-loopcontrol technique


9/12


Power Electronics Conference, APEC, pp. 1145-1148, , 25 Feb. -1March 2007.

[10] Jin-Woo Jung and Ali Keyhani: Control of a Fuel Cell Based Z-Source Converter, IEEE Transactions on Energy Conversion, Vol.22, No. 2, pp. 467- 476, , June 2007.

[11] M.J.; Rastegar Fatemi, S. Mirzakuchaki, S. Rastegar Fatemi:Wide-Range Control of Output Voltage in Z-Source Inverter byNeural Network, The International Conference on ElectricalMachines and Systems, ICEMS, pp.1653-1658, 17-20 Oct. 2008.

[12] Miaosen Shen; Qingsong Tang; Peng, F.Z.: Modeling andController Design of the Z-Source Inverter with Inductive Load,The IEEE Power Electronics Specialists Conference, PESC, pp.1804-1809, 2007.

[13] Cheng Ruqi, Zhao Gengshen, Guo Tianyong, Zhao ergang, Zhaoyao and Qi chao: Modeling and State Feedback Control of Z-source Inverter, The 2nd International Conference on PowerElectronics and Intelligent Transportation System (PEITS), pp.125-129, 19-20 Dec. 2009.

[14] A.H. Rajaei, S. Kaboli, A. Emadi: Sliding-mode control of Z-source inverter, The 34th Annual Conference of IEEE IndustrialElectronics, IECON, pp. 947-952, 10-13 Nov. 2008.

[15] Quang-Vinh Tran, Tae-Won Chun, Jung-Ryol Ahn and Hong-HeeLee: Algorithms for Controlling Both the DC Boost and AC Output

Voltage of Z-Source Inverter, IEEE Transactions on IndustrialElectronics, Vol. 54, No. 5, pp. 2745-2750, October 2007.

[16] Quang-Vinh Tran, Tae-Won Chun, Heung-Gun Kim, and Eui-Cheol Nho: Minimization of Voltage Stress across SwitchingDevices in the Z-Source Inverter by Capacitor Voltage Control,Journal of Power Electronics, Vol.9, No.3, pp.335-342, 2009.

[17] H. Rostami, D. A. Khaburi: Neural Networks Controlling for Boththe DC Boost and AC Output Voltage of Z-Source Inverter, The 1st

Power Electronic & Drive Systems & Technologies Conference,PEDSTC, pp. 135-140, 17-18 Feb. 2010.

[18] Xinping Ding, Zhaoming Qian, Shuitao Yang, Bin Cui, Fang zheng

Peng: A Direct DC-Link Boost Voltage PID-Like Fuzzy ControlStrategy in Z-Source Inverter, The IEEE Power ElectronicsSpecialists Conference, PESC, pp. 405-411, 15-19 June 2008.

[19] Yu Tang, Shaojun Xie and Chaohua Zhang: Feedforward plus feedbackcontrol of the improved Z-source inverter, IEEE Energy ConversionCongress and Exposition, ECCE, pp. 783-788, 20-24 Sept. 2009.

[20] Xinping Ding, Zhaoming Qian, Shuitao Yang, Bin Cui, FangzhengPeng: A Direct Peak DC-link Boost Voltage Control Strategy in Z-Source Inverter, The Twenty Second Annual IEEE Applied PowerElectronics Conference, APEC, pp. 648-653, 25 Feb. -1 March2007.

[21] Yu Tang, Jukui Wei, Shaojun Xie: A New Direct Peak DC-linkVoltage Control Strategy of Z-source Inverters, The Twenty-FifthAnnual IEEE Applied Power Electronics Conference andExposition, APEC, pp. 867-872, 21-25 Feb. 2010.

[22] G. Sen, M. Elbuluk: Voltage and Current Programmed Modes in


(a)

(c)

(b)

(d)

Fig. 11: ZSI response during input voltage step down by 7.5 %: (a and c) simulation results and (b and d) experimental resultsusing dual-loop control technique


10/12


Control of the Z-Source Converter, IEEE Transactions on IndustryApplications, Vol. 46, No. 2, pp. 680-687, March-April 2010.

[23] Shuitao Yang, Xinping Ding, Fan Zhang, F. Z. Peng, andZhaoming Qian: Unified Control Technique for Z-Source Inverter,The IEEE Power Electronics Specialists Conference, PESC, pp.3236-3242, 2008.

[24] Xiaoyu Wang, D. M. Vilathgamuwa, K. J. Tseng and C. J.Gajanayake: Controller design for variable-speed permanent mag-net wind turbine generators interfaced with Z-source inverter, The

International Conference on Power Electronics and Drive Systems,PEDS, pp. 752-757, 2-5 Nov. 2009.

[25] D. G. Holmes, B. P. McGrath, D. Segaran and W. Y. Kong:Dynamic Control of a 20kW Interleaved Boost Converter forTraction Applications, the IEEE Industry Applications SocietyAnnual Meeting, IAS, 5-9 Oct. 2008.

[26] Omar Ellabban, Joeri Van Mierlo and Philippe Lataire: A DSPBased Dual Loop Digital Controller Design and Implementation ofa High Power Boost Converter for Hybrid Electric VehiclesApplications, the Journal of Power Electronics (JPE), Vol. 11, No.2, pp.113-119, March 2011.

[27] T. Suntio, I. Gadoura and K. Zenger: Small-Signal Modelling ofSwitched-Mode Converters - A Unified Approach, Nordic work-shop on power and industrial electronics, 12-14 Agust 2002.

[28] M. Veerachary: General rules for signal flow graph modeling andanalysis of DC-DC converters, IEEE Transactions on Aerospace

and Electronic Systems, Vol. 40, No. 1, pp. 259-271, Jan. 2004.

[29] Jingbo Liu, Jiangang Hu, Longya Xu: Dynamic Modeling andAnalysis of Z-Source Converter-Derivation of AC Small SignalModel and Design-Oriented Analysis, IEEE Transactions onPower Electronics, Vol.22, No. 5, pp. 1786-1796, Sept. 2007.

[30] Veda Prakash Galigekere and Marian K. Kazimierczuk: Small-Signal Modeling of PWM Z-Source Converter by Circuit-Averaging Technique, IEEE International Symposium on Circuitsand Systems (ISCAS), pp.1600-1603,15-18 May 2011.

[31] Omar Ellabban, Joeri Van Mierlo and Philippe Lataire: Design andImplementation of a DSP Based Dual-Loop Capacitor VoltageControl of the Z-Source Inverter, the International Review ofElectrical Engineering (IREE), Vol. 6, No. 6, pp. 98-108, February2011.

[32] Veerachary Mummadi: Design of Robust Digital PID Controllerfor H-Bridge Soft-Switching Boost Converter, IEEE Transactionson Industrial Electronics, Vol. 58, N0. 7, pp. 2883 2897, July2011.


(a)

(c)

(b)

(d)

Fig. 12: ZSI response during load increasing and decreasing by 50 % : (a and c) simulation results and (b and d) experimentalresults using dual-loop control technique


11/12



(a)

(c)

(e)

(b)

(d)

(f)

Fig. 13: Steady state response of the ZSI: (a, c and e) simulation results and (b, d and f) experimental result using dual-loop con-trol technique


12/12


The authors

Omar Ellabban was born in Egypt in 1975. He received the B.Sc. fromHelwan University, Egypt in 1998 and the M.Sc. degree from CairoUniversity, Egypt in 2005, both in Electric Power and Machines

Engineering, and the Ph.D. degree in Electrical Engineering from VrijeUniversiteit Brussel, Belgium in May 2011 with the greatest distinction.

In May 2011, he joined the R and D departmentat Punch Powertrain, Sint-Truiden, Belgium,where he and his team develop a next generation,highly performing hybrid Powertrain. Hisresearch interests include motor drives, artificialintelligent, power electronics converters design,modeling and control, electric and hybrid electricvehicles control, DSP-based system control andswitched reluctance motor control for automotiveapplications. He is a member at the IEEE, JPEand EPE journals.

Prof. Dr. ir. Joeri Van Mierlo obtained his Ph.D.in electromechanical Engineering Sciences fromthe Vrije Universiteit Brussel in 2000. He is nowa full-time professor at this university, where heleads the MOBI - Mobility and automotive tech-nology research centre (http://mobi.vub.ac.be).Currently his activities are devoted to the devel-opment of hybrid propulsion (power converters,energy storage, energy management, etc.) sys-

tems as well as to the environmental comparisonof vehicles with different kind of drive trains andfuels (LCA, WTW). Prof. Van Mierlo is Vice-

president of AVERE (www.avere.org), is the secretary of the board ofthe Belgian section of AVERE (ASBE) (www.asbe.be). He chairs theEPE chapter Hybrid and electric vehicles (www.epe-association.org).He is member of ERTRACs Energy & Environment Working Group(European Research Transport Advisory Council). He is an active mem-ber of EARPA - the European Automotive Research PartnerAssociation. Furthermore he is member of Flanders Drive and of VSWB Flemish Cooperative on hydrogen and Fuels Cells. He is the author ofmore than 200 scientific publications. He is editor in chief of the WorldElectric Vehicle Journal Volume 3 and co-editor of the Journal of AsianElectric Vehicles and member of the editorial board of Studies inScience and Technology. Prof. Van Mierlo was Chairman of theInternational Program Committee of the International Electric, hybrid

and fuel cell symposium (EVS24).

Philippe Lataire received a degree inElectromechanical Engineering in 1975 and hisPh.D. in 1982, both from Vrije UniversiteitBrussel (VUB), Brussels, Belgium. He ispresently a Full Time Professor at VUB. His cur-rent research interests include electric drives,power electronics and control.


(a)

(c)

Fig. 14: Z-domain root locus for single-loop (a) and dual-loop(b) capacitor voltage controlled ZSI

epe_capacitor_voltage_control_techniques_of_the_z-source_inverter_a_comparative_study-libre.pdf

Documents