Voltage and Frequency Control of Variable Speed Induction Generator using One Cycle Control Technique

International Journal of Power Electronics and Drive System (IJPEDS)
Vol. 6, No. 4, December 2015, pp. 723~729
ISSN: 2088-8694  723
Journal homepage: http://iaesjournal.com/online/index.php/IJPEDS
Voltage and Frequency Control of Variable Speed Induction
Generator using One Cycle Control Technique
T. Elango1
, A. Senthil Kumar2
1
Anna University, Chennai & Department of EEE, Sri Balaji Chockalingam Engg. College, Arni, Tamil Nadu, India
2
Department of EEE, Velammal Engg. College, Chennai, Tamil Nadu, India
Article Info ABSTRACT
Article history:
Received Apr 24, 2015
Revised Aug 11, 2015
Accepted Sep 10, 2015
Induction generators are widely used to extract the energy from renewable
sources, particularly as a wind power generator either grid connected or
isolated operation. The problem associated with stand-alone mode operation
is voltage and frequency control. An electronic load controller is used for
frequency / voltage control. It uses PI controller to generate the gating signal
for the DC chopper. This method has the fault of bad dynamic response and
thedistortion of output voltage at zero-crossing. To overcome the defect of PI
controller when steady state error is equal to zero, a one cycle control
technique suggested and implemented. Simulation of wind driven self-
excited induction generator (SEIG) performance is studied and results are
discussed.
Keyword:
Electronic load controller
Frequency control
Induction Generator
One cycle control
Voltage control Copyright © 2015 Institute of Advanced Engineering and Science.
All rights reserved.
Corresponding Author:
T. Elango,
Research Scholar, Anna University,Chennai,
Associate Prof., Departement of EEE,
Sri BalajiChockalingamEngg. College, Arni, Tamil Nadu, India.
Email: telango_arni@yahoo.co.in
1. INTRODUCTION
To meet the shortfall in power demand, power generation from wind contributes major role among
other renewable energy sources such as solar, tide etc., and, advancement of power electronics technology
also support to generate more power from wind. The future trend of wind energy conversion systems
(WECS) is to increase the power capacity of wind turbines and generators to reduce the cost of generated
electricity[1]-[5]. The power electronic technologies used in wind turbine application have changed
dramatically during last 30 years [6]-[7].
In remote area electric power supply, standalone operation of SEIGs has a vital role. In order to
optimize the cost of the system induction motor is used as generator. It has significant advantages such as
easy maintenance and control, no need of separately exciting source instead of that, capacitor connected
across the stator winding is sufficient to excite the machine, and, rugged in rotor construction is more suitable
for wind turbine rotations. The voltage generation and generated frequency depends on the wind velocities.
The problem associated with this scheme is to control the frequency and voltage.
Bhim Singh et al [8] suggested a load control technique to solve the above problem. Transient
analysis of SEIG considered on their further research [9]. However, the method suggested by them
incorporated PI controller to generate the gate pulse for the chopper switch which is controlling power flow
through the dump load/ additional load.
One-cycle control is a typical practical nonlinear controltechnology; it has rapid dynamic response and
trackperformance [10]. It is designed to control the duty-ratioof the switch in real time. The aim of this work
to eliminate the problem associated with PI controller as and when the steady state error is zero by
implementing one cycle control (OCC). The OCC is presented in subsequent section in detail.

 ISSN: 2088-8694
IJPEDS Vol. 6, No. 4, December 2015 : 723 – 729
724
This paper organized as section 2 describes the system configuration, Frequency control, one cycle
control and its operation. Simulated results and conclusion presented in section 3 and 4 respectively.
2. SYSTEM CONFIGURATION
The proposed system is shown in Figure 1. It comprises with SEIG, Electronic load controller, one
cycle controller, consumer load and wind turbine emulator.
Figure 1. Schematic diagram of SEIG with Electronic Load controller and one cycle controller
The torque generated by the wind turbine emulator with wind velocity of 6 m/sec is applied to the
induction motor. Since the torque is in negative and adequate capacitor connected across the stator winding,
as soon as the rotor speed exceed the synchronous speed (Ns = 120f/P) voltage induced across the stator
winding and also builds up, to the rated value is called self-excitation process. So called self-excited
induction generator.
The SEIG supply the power to a three-phase wye connected consumer load and an additional (dump
load) is shown in Figure 1. Dump load is controlled by the proposed one cycle controller. The function of the
controller is to maintain the power generated by SEIG is constant at all condition.
2.1. Frequency Control
The Electronic load controller can be used to connect or disconnect the dump load whenever the consumer
load fluctuates. It consists of a diode rectifier and a step down chopper circuit connected in series with a
dump load. The duty cycle of the IGBT switch is controlled depending on the variations in consumer load
which eventually decide the amount of power to be dumped.
The AC voltage from the SEIG terminal is rectified by means of an uncontrolled bridge rectifier and
a capacitor is connected across the diode bridge rectifier to filter out the ripples. The effective input
resistance seen by the source at point of common coupling (PCC) is,

R
R
V
V
I
V
R
s
s
o
s
i 
(1)

IJPEDS ISSN: 2088-8694 
Voltage and Frequency Control of Variable Speed Induction Generator using One Cycle .... (T. Elango)
725
From eqn. (1), the duty cycle can be varied from 0 to1 by varying T or f and the input resistance (Ri)
as a function of duty cycle α.
2.2. One Cycle Control Tecnique
One cycle control can be used to control a switched variable and a switch controlled by this method
fully rejects the input signal and reproduces the control reference at the output [10]. The basic assumption
here is that the switching frequency is much higher than the maximum frequency of the input and reference
signals.
One cycle controller uses the constant frequency pulse to turn on and turn off the transistor and
active the integrator. It is new non linear control technique implemented to control the duty ratio of switch in
real time, in each cycle the average value chopping waveform of switch output is exactly same as control
reference voltage. This sample signal is taken from the chopped voltage not from the output voltage.
One-cycle control method reject input voltage perturbation in only one switching cycle and follow the control
reference very quickly.
Let u(t) be an input to a switch operating at variable on and off times (Ton and Toff),total cycle time
Ts, duty ratio d(t) and producing the average of the switched output i.e., effective signal, is
)()(
0
)(
1
)( tdtudt
T
tu
T
tw
ON
s
 
(2)
The duty ratio has to be generated as a control input to the switch based on areference signal vref (t).
The integration of the switched variable is made exactly equal to the integration of the control reference by
regulating the duty-ratio of the switch in each cycle, i.e.,
dtt
T
ref
Vdt
T
tu
sON
)(
00
)(  
(3)
If the switching period is constant in each cycle, then the average value of the switched variable is
precisely equal to control reference. Thus, the average of the switched variable at the switch output is
controlled instantaneously within one cycle of time duration, i.e.,
)()(
0
1
0
)(
1
)( tVdtt
T
ref
V
T
dt
T
tx
T
ty ref
s
s
ON
s
 
(4)
The nonlinear technique used to control switches based on this concept is known as the “One-Cycle
Control technique” (OCC). With thistechnique, the effective output signal of the switch is
)()( tuVtw ref
(5)
In OCC technique, the non-linear switch leads into a linear path by rejecting the input signal of the
switch and linearly passing the control reference Wref.The integrator and the re-setter are the key components
of the OCC technique. As the switch is turned on with the fixed frequency clock pulse, the integration gets
starts. The integration value is,
dt
t
txkV 
0
)(int
(6)
Where k is a constant the integration value and the control reference Vref(t) are compared
instantaneously. Thus, the controller made the switch to turned off when the integration value Vint reaches the
control reference Vref(t) and the controller automatically resets the integrator value to zero. The duty ratio (d)
of the present cycle is calculated by using the following equation:

 ISSN: 2088-8694
726
)(
0
)( tVdt
dT
tuk ref
s

(7)
Since the switch period, T = constant and K = l/kTs is also constant. Thus, the average value of the
switched variable in each cycle at the switch output y (t) is admitted to be
)(
1
0
)(
1
)( tV
kT
dt
dT
tu
T
tw ref
s
s
s
 
(8)
This control strategy can be implemented with a simple integrator with reset. Areset pulse is
generated by a clock of required switching frequency. At the start of everycycle the switch is turned on by the
reset pulse. The input is integrated and when theintegrated output just exceeds the reference signal vref, the
switch is turned off. Theintegrator resets after time Ts and the switch goes on again.
3. MATLAB/SIMULK BASED SIMULATION RESULTS
Simulink connection of wind driven SEIG employed in standalone power supply for a remote places
and its control is shown in Figure 2.
Figure 2. Simulation circuit of proposed system
One cycle control technique is implemented using the built-in libraries of power system toolbox of
Matlab/Simulink softwareis shown in Figure3.In order to solve the equation ode23tb is considered for the
simulation time of 6 seconds.
Figure 3. Implementation of one cycle control in Matlab/Simulink

727
The consumer load of 323W and 200W is connected at 2.5 and 4 seconds respectively. Voltage and
frequency is controlled by controlling the active power consumed by the consumer and dump loads.
3.1. Voltage Control
The source voltage and current waveform is shown in Figure 4(a), the load voltage and current
waveform is shown in Figure 4(b).
Figure 4(a). Source voltage and current waveforms Figure 4(b). Load voltage and current waveforms
Figure 5 illustrate the active power generation of SEIG and feeding to the loads, from 2.5 to 4 and
4 to 6 seconds the consumer load is connected to the SEIG terminals and the variations is shown in Figure
5(b).
Figure 5. variations of active power in (a) source, and (b) consumer load.
Figure 6 illustrate the variations of dc voltage and power consumed by the dump load.

 ISSN: 2088-8694
728
Figure 6.Variations of dc voltage and power across the dump load
3.2. Frequency Control
Figure 7 illustrates the frequency variations; it lies within in the prescribed limit.
Figure 7. Frequency variations
4. CONCLUSION
A simple voltage and frequency control of SEIG using one cycle control is simulated and results are
discussed. The result shows the terminal voltage is almost nearly constant irrespective of wind velocity. It is
observed that there is voltage reduction in SEIG terminal before point of common coupling (PCC) slightly
because of inductance connected before the dumb load controller needs a reactive power controller.
ACKNOWLEDGMENT
The authors acknowledge the management and the research committee members, for their valuable
successions to complete this work successfully.
REFERENCES
[1] Bansal, RC., “Three-Phase Self-Excited induction generators: An over View”, IEEE Transactions on Energy
Conversion, vol/issue: 20(2), pp. 292-299, 2005.
[2] Senthil Kumar, A., Singh, GK., Saini, RP., “A self-excited six-phase induction generator for stand-alone renewable
energy generation”, European Transactions on Electrical Power, vol/issue: 20(7), pp. 884-900, 2010.
[3] T. Elango, A. Senthil Kumar, “Investigation of an Induction Motor performance working as Generator with Motor
parameters”, International Journal of Applied Engineering Research, vol/issue: 9(22), pp. 16613-16623, 2014.
[4] Ridwan Gunawan, et al, “The Self Excited Induction Generator with ObservationMagnetizing Characteristic in the
Air Gap”, International Journal of Power Electronics and Drive System, vol/issue: 5(3), pp. 355~365, 2015.

729
[5] Mohamed Barara, et al, “Advanced Control of Wind Electric Pumping System forIsolated Areas Application”,
International Journal of Power Electronics and Drive System, vol/issue: 4(4), pp. 567~577, 2014.
[6] F. Blaabjerg, M. Liserre, Ke Ma, “Future on Power electronics for wind turbine systems”, IEEE Trans. on
Emerging and Selected Topics in Power Electronics, vol/issue: 1(3), pp. 139 –151, 2013.
[7] F. Blaabjerg, M. Liserre, Ke Ma, “Power electronic converters for wind turbine systems”, IEEE Trans. on Indust.
Appli.., vol/issue: 48(2), pp. 169–176, 2012.
[8] Bhim Singh, SS. Murthy, Sushma Gupta, “Analysis and Design of Electronic Load Controller for Self-Excited
Induction Generator”, IEEE Trans. on Energy Conver, vol/issue: 21(1), pp. 285-293, 2006.
[9] Bhim Singh, SS. Murthy, Sushma Gupta, “Transient Analysis of self-Excited Induction Generator with Electronic
Load Controller supplying Static and Dynamic loads”, IEEE Trans. on Indust. Appli. Vol/issue: 41(5), pp. 1194-
1204, 2005.
[10] KM. Smedley, S. Cuk, “One-cycle control of switching converters", IEEE Transactions on Power Electronics,
vol/issue: 10(6), pp. 625-633, 1995.
BIOGRAPHIES OF AUTHORS
T.Elango obtained is Bachelor’s Degree in Electrical Engineering from Bangalore University in
the year 1996. He obtained is Master’s degree in Applied Electronics from University of Madras
in the year 2001. He is currently pursuing the Ph.D. in Electrical Engineering at Anna
University, Chennai. His current research includes Renewable-Energy Generation, Power
Electronics converters and Power Quality issues in Renewable Energy. He has a teaching
experience of 17 years. He has published 3 papers in international journals and presented 3
papers in National & International conferences. He has attended many seminars and
workshops.He is life member of Indian Society of Technical Education (ISTE). He is a Ph.D
research scholar of Anna University, Chennai. At present he is working as Head of the EEE
department at Sri Balaji Chockalingam Engineering College, Arni.
Dr. A.Senthil Kumar, obtained is Bachelor’s Degree (1996) in Electrical and Electronics
Engineering in first class from University of Madras, Chennai, Tamil Nadu. He obtained is
Master’s degree (2000) in Power Electronics and Drives in first class from Bharathidasan
University, Trichy, Tamilnadu, and also he obtained is Master’s degree (2006) in Human-
Resource Management in first class from TNOU, Chennai. He completed his Doctoral degree
(2010) in the area of Electrical Engineering from Indian Institute of Technology Roorkee,
Roorkee, Uttarakhad, India. He is also completed isPost-doctoral research fellow in Centre for
Energy and Electrical Power, Electrical Engineering Department, Faculty of Engineering and the
Built Environment, Tshwane University of Technology, Pretoria, South Africa for a period of
one year from 2012-13. He obtained many awards and certificates during M.E and Ph.D studies.
He has 17 years of teaching and research experience. He has published 25 papers in international
journals and presented 30 papers in international and national conferences. He has attended
many international seminars and workshops. He is a life member of many professional bodies
like ISTE, IEI, CSI, IAENG, IACSIT, etc.; He visited foreign countries such as Hong Kong
Chengudu& Mauritius which was financially supported by DST, CSIR and NRF. He has
delivered state of the art lectures in many educational institutions and professional societies. He
is currently doingan on-going project funded by AICTE worth of 33 lakhs. His research interests
include Multiphase Machines, Power Electronics, Renewable-Energy Generation Source,
Microcontroller & VLSI application in Power Electronics & Electric Drives, Active Filters
Stability and System Analysis. Currently, he is working as Professor/EEE at Velammal
Engineering College, Chennai,Tamil Nadu.

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