Speed Control Of Fuel Cell Driven PMSM Using IDDB Converter With LQR Control

Speed Control Of Fuel Cell Driven PMSM

Using IDDB Converter With LQR Control

J.S.V.Siva Kumar, P.Mallikarjuna Rao

Abstract : The conspicuousness of Fuel Cell based Electric Vehicles (FCEV) has been taking off in advancements being actualized in electric cars because of their principle focal points of eco-accommodating nature, plentiful effectiveness and extraordinary dependability. The design and simulation of fuel cell based electric vehicle is explained in this paper. These FCEVs consists ―rechargeable energy storage system‖ (RESS) and also provide better acceleration along with regenerative braking. The output voltage of thet stack of fuel cell is significantly low, subsequently it is expanded by utilizing Interleaved Double Dual Boost converter with LQR control. The increased output of boost converter is given as input to the inverter for getting AC to run PMSM. Gating pulses are given to the inverter by the utilization of Space Vector PWM method and the output of inverter is provided to the PMSM drive through LC filter so as to lessen ripples in the output of inverter. The results are established by simulation strategies using MATLAB/Simulink.

Index Terms: Fuel cell system, IDDB converter, Boost Converter LQR control, SPVPWM, PMSM, electrical vehicles. ——————————  ——————————

1.

INTRODUCTION.

These days contamination is expanding a result of petroleum products which are utilized in the greater part of the automotive industries. Thus it is mandatory for improvement of ecofriendly electrical vehicles. The fuel cell technology is required to transform into a charming wellspring of intensity for vehicle applications due to their eco-accommodating nature in recent years, reduced noise pollution, more efficiency and reliability. PEMFC is given priority for utilization in electric vehicles compare to all types of FC systems because of their Significant characteristics lilke high-power density laterally with operating temperatures at lower levels in [1]-[6],. The output Power developed is being in the cutoff points of any watts to around hundred kilowatts and the open circuit turns into the obstacle on account of PEMFC. The scope of voltage in the single cell is nearly 0.8V to 1.2V. To get high voltage and power the cells are connected in series/parallel. This voltage is not enough to drive the motor.so it is required to boost voltage by interfacing the DC/DC converter with high voltage gain.In the EVs, The needed conditions for an electrical drive comprise more efficiency, low volume, lesser weight, and low cost. But now a days PMSM drive having higher performance as compared to AC motors such as high values of speed, torque and efficiency.[7] The main drawback of PMSM drive is the ripples in the torque. Because of this ripples it won‘t give any considerable operation. The better speed control is attained, ripples also minimized and also gating pulses for the switches of the inverter also generated by using Space Vector Pulse Width Modulation

2.

PROPOSED

SYSTEM.

The fuel cell based electric vehicle block diagram is shown in Fig1. Its comprises Fuel cell, DC-DC Boost converter, SVPWM controlled VSI fed PMSM.

The output voltage of single fuel cell is nearly 0.8V to 1.2V. So it is required to combine number of cells in series/parallel for getting high operating voltages. In this paper the output of the fuel cell stack is nearly 60Vand this is increased to 360V DC by using IDDB converter which is controlled by LQR controller[10] for getting controlled output. In this paper IDDB converter with closed loop operation is suggested for achieving high operating voltage, LQR controller is used as controller in feedback circuit. In this paper the output of IDDB [8,9]converter is nearly 360V which is input to Inverter to convert this DC to AC voltage. The ripples in AC voltage are minimized by connecting PMSM through LC filter and the gating pulses for the switches of the inverter are generate using space vector pulse width modulation technique.[2]-[7]

Fig1. Fuel cell based PMSM Drive

3.

PEM

FUEL

CELL

SYSTEM

MODELING.

Fuel cell is a device is normally used to convert the chemical form of energy to Electrical energy. In Electric vehicles normally we can use different types of fuel cells but out of which PEM fuel cell is having more importance because of its operation with temperature with high power density. The clear diagram of PEMFC is shown in fig.2

________________________________

Fig.2 PEM Fuel Cell

In the fuel cell chemical reaction starts at anode. At anode hydrogen is separated to electrons and protons. Protons are passes through electrolyte whereas electrons are flowing through the external circuit, developing electrical energy at the fuel cell. Air from cathode and hydrogen from anode combines develops water at outlet of fuel cell.

Reaction at Anode :

H

₂



2

H





2

e

 (1) Reaction at Cathode :

O

₂

2

H

2

e

H

₂

O

2

1

_



_



_

(2)

Complete reaction :

H

2

O

2

H

2

O

2

1

_



(3)

The output voltage developed at fuel cell is quantified by using Ohms law and Nernst‘s equation.

V

_fc



E



V

_act



V

_ohmic



V

_conc (4)

Where E is Thermodynamic reversible potential

act

V

is activation over voltage

ohmic

V

is Ohmic voltages (Vohmic)

conc

V

is Concentration over voltages

And all these values are measured by using below formulas













3

0 0 2 2

1

0.85 10 ln ln

2 2

R

E E T T T PH Po

F

  

     _  _

 

(5)

0

l o g

a c t

R T I V

Z F I





(6)

V

ohmic



I

(

R

m



R

c

)

(7)



















lim

1

log

I

I

ZF

RT

V

conc (8)

4.

FUEL

CELL

SUPPLIED

LQR

CONTROL

OF

IDDB

CONVERTER

The two phases IDDB is shown in Fig. 3, where ‗RO‘ represents

the load. Each phase of the converter comprise a conventional boost module with an inductor and its corresponding couple of switches. Phase1 and capacitor C1 are here denoted by

―module 1‖ vice versa.

Assumption : Two modules of the converter are symmetric. The duty cycle δ is variable and it is identical to both the modules. The model is concerned with the capacitors voltages.

Fig. 3. IDDB With TWO phases. As pointed, this topology facilitates modular structure permitting more than two phases. To attain symmetry, an even multiple of phases are preferred. This section is to generalize the converter modeling to N-phase topology. The phases of the upper group are connected to C1 whereas lower group are

connected to C2. All upper group is one module and lower is

another module and multiphase IDDB are shown in fig.4.

Fig.4. Six phase IDDB The source current is given by:

i

_in



i

₁



i

₂



i

₃



...



i

_N



i

₀ (9) The state variables of N-phase IDDB are N+2, which are ‗N' inductor currents and two capacitor voltages.

The differential equation for the current in each module is given by



_{k k k in}



k

k

R

I

V

V

L

I

dt

d

_

_

_

_

_

1

1

for k =1..., N/2. Similarly for k=(N/2)+1 to N The voltage in C1 is given by V1

Is represented by differential equation

V1 = ]

(11) Similarly for voltage across C2

Now, by assuming system Is symmetry that means in two phase all inductances and capactors are same and also the currents and duty cycles in each phases are same in all phases that means

I 1 = I 2 = ……..= I N = I



₁





₂



...





_N





Then



RI

V

V

_in



L

I

dt

d









1



(12)

and

 





















0

2

2

1

R

V

V

I

N

C

V

dt

d



_in

(13)

The state vecor X is defined by

X =





I

I

V

(14) whereas input matrix are

A =

0

2

2

R

L

L

N

C

R C



































B =

0

1

1

L

R C

























(15)

The reference values are taken for simulation are given below Vin = 60 V, R = 0.15 Ω, L = 535 µH, C = 470 µF R0 =59Ω,

fsw = 10 kHz, δ = 0.73.

4.1. METHODOLOGYOFLQRCONTROLLER

The finite horizon, linear quadratic regulator (LQR) is given by

Bu

Ax

x







y



Cx

0 m

n

,

,

,

u

y

x

x













p given









 T T T

dt Ru u Qx x J

0

2 1

where Q ≥ 0, R > 0, P1≥ 0, are symmetric, positive

(semi-) definite matrices. The Q and R are weight matrices for states and control input respectively.

The LQR control input is given by

u





kx

‗

k

‘ is

LQR gain and is given by

k



R

1

B

T

P

And ‗P‘ can be obtained from algebraic Ricatti equation solution of

0

1











Q

P

B

PBR

PA

P

A

T T

Fig.5. Control Diagram of the implemented controllers

5.

SVPWM

CONTROLLED

VSI

Fig6. Three-Phase VSI

Schematic drawing of a three-leg voltage source inverter is shown in Fig6.Gating pulses for three phase inverter are generated by using Space vector pulse width modulation technique. In this technique various switching sequence are to be there for generating output voltage

Fig7. Three-Phase VSI Switching states

0 0.01 0.02 0.03 0.04 0.05 0.06 0

100 200

V2

0 0.01 0.02 0.03 0.04 0.05 0.06 0

100 200

V1

0 0.01 0.02 0.03 0.04 0.05 0.06 0

200 400

Time

Vo

0.1 0.15 0.2 0.25 0.3 0.35 0.4

-400 -200 0 200 400

Time

O

ut

pu

t V

ol

ta

ge

Fig 8. Space vector diagram of the inverter

Three-Phase Voltage Source inverter Switching states are shown in fig7. SVPWM technique of the inverter consists of eight space vectors, in that two zero state vectors(V0(000) and

V7(111)) and the six remaining vectors are called active

vectors(V1,V2,V3,V4,V5,V6) are shown in fig 8. The gating pulses

which are produce by SVPWM are given to Inverter for getting ripple free AC output voltage.

6.

PMSM

DRIVE

CONTROL

STRATEGY

The PMSM control has two main parts one is driver circuit and other is control circuit. In this main drive circuit is remains same and only focusing on control circuit. In this PMSM is controlled by v/f method. In this the speed of PMSM is compared with reference speed, and then the error of this is given to the PI controller as an input. The generating pulses In SVPWM are by Proper modulation of voltage signal which is the output of PI controller. The main advantage of this method is sensors are not required for estimating the speed.

7.

SIMULATIONS

AND

RESULTS

Fig 9. Simulink Model of Electric Vehicle

Fig10. Output Voltage of Fuel Cell Stack

0.055 0.051 0.052 0.053 0.054 0.055

10 15 20 25

Time

In

p

u

t

C

u

rr

e

n

t

Fig11. Input Inductor Current of IDDB

Fig12. Output voltage of IDDB

Fig13. Output Voltage of Inverter

0.2 0.25 0.3 0.35 0.4

-10 -5 0 5 10

Time

O

u

tp

u

t

C

u

rr

e

n

t

0 0.1 0.2 0.3 0.4 0.5 0

100 200 300 400

S

p

e

e

d

0 0.1 0.2 0.3 0.4 0.5

-4 -2 0 2 4

Time

To

rq

u

e

0 0.1 0.2 0.3 0.4

0 200

S

p

e

e

d

i

n

R

P

M

0 0.1 0.2 0.3 0.4

-5 0 5

Time

T

o

rq

u

e

I

n

N

-M

Fig.15. Speed and Torque Under No Load Load

Fig.16. Speed and Torque Under Step Load

0 0 . 1 0 . 2 0 . 3 0 . 4

- 5 0 0 0 500

S

p

e

e

d

i

m

R

P

M

0 0.1 0.2 0.3 0.4

-5 0 5

Time

T

o

rq

u

e

I

N

N

-m

Fig.17. Speed and Torque Under Ramp Load

8. CONCLUSIONS.

In this paper the modelling and simulation of fuel cell is done and output voltage of the stack of fuel cell is nearly 60 V. It is clearly observed the power handling capability of IDDB increases with the number of phases, that means the output voltage is more for six phase IDDB as compared to two phase IDDB. The output voltage of the inverter is nearly 350V ripple free by using SVPWM and It is given to PMSM under different load conditions. It is clearly observed the PMSM is running stable condition under step and ramp load .Simulation results are supported the theoretical analysis.

9

REFERENCES

[1] A. A. Salam, A. Mohamed, and M. A. Hannan, ―Modeling and Simulation of a PEM Fuel Cell System Under Various Temperature Conditions,‖ 2nd WSEAS/IASME International Conference on RENEWABLE ENERGY SOURCES (RES'08) Corfu, Greece, October 26-28, 2008pp. 204–209, 2008.

[2] .R.Chaitany,J.S.V.SivaKumar,M.Rambabu ―Fuel Cell Supplied SVPWM Controlled Inverter Fed PMSM Drive in an Electrical Vehicle‖ International Journal of Engineering Research & Technology, Vol. 3 Issue 9, September- 2014 [3] Maria Teresa Outeiro and Adriano Carvalho ―Methodology of

Designing Power Converters for FuelCell Based Systems‖ http://dx.doi.org/10.5772/54674, April 2013

[4] J.S.V.Siva Kumar, P.Mallikarjuna Rao, ―Design and Simulation of Front End Converter For Fuel Cell Based Electric Vehicle Applications‖, IEEE International Conference on Power,Control,Signalsand Instrumentation Engineering(ICPCSI-0070), Saveetha Engineering College, Chennai, September 2017

[5] J.S.V.Siva Kumar, P.Mallikarjuna Rao, ―Design and Simulation of DC-DC Converter For Fuel Cell Based Electric Vehicle With Closed loop operation‖, Springer International Conference on Soft Computing in Data Analytics(SCDA 2018), Sivani Engineering College,Andhrapradesh,10th - 11th March 2018.

[6] J.S.V.Siva Kumar, Potunuru Venkata Sateesh, ―Design and Simulation Of A Current Fed Full Bridge Voltage Doubler Converter With High Voltage Gain For Fuel Cell Based Electric Vehicle‖, Journal of Advanced Research in Dynamical and Control Systems, Vol. No.x, Issue No.16, pp 110-121, November 2017

[7] Permanent Magnet Synchronous and Brushless DC Motor Drives by R.Krishnan,1st edition, CRC press, September 2009

[8] Fellipe S. Garcia, José Antenor Pomilio, Giorgio Spiazzi,‖ Modeling and Control Design of the InterleavedDouble Dual Boost Converter,‖ IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 60, NO. 8, AUGUST 2013

[9] Pi-Yun Chen, Kuei-Hsiang Chao and Hong-Jhih Chen,‖Modeling and quantitative design of a controller for a bidirectional converter with high voltage conversion ratio‖ in international Journal of Innovative Computing, Information and Control in Volume 14, Number 6, December 2018. [10] Emmanuel Okyere, Amar Bousbaine, Gwangtim T. Poyi, Ajay