Indirect Vector Control of Stand-Alone Self-Excited
Induction Generator
1
S. N. Mahato1, S. P. Singh2, and M. P. Sharma3
Department of Electrical Engineering, National Institute of Technology, Durgapur, India
2
Department of Electrical Engineering, Indian Institute of Technology, Roorkee, India
3
Alternate Hydro Energy Centre, Indian Institute of Technology, Roorkee, India
Abstract - This paper presents the voltage build-up process
and the terminal voltage control of a stand-alone self-excited
induction generator (SEIG) using indirect vector control
(IVC) technique under variable speeds and different types of
load. Here, the three-phase SEIG is excited by a pulse-width
modulated voltage source inverter (PWM-VSI) connected to a
single-capacitor on the DC side with a start-up battery. The
limitation of having stand-alone SEIG is poor voltage
regulation, which occurs with change in speed and load
condition. Hence, there should be a control system that keeps
the terminal voltage of the SEIG and the DC bus voltage
constant when the speed of the rotor and also, the load on the
SEIG are varied. The indirect vector control scheme has been
presented to maintain the terminal voltage of the generator
and the DC bus voltage constant for variable rotor speed and
load. The space-phasor model of the induction machine has
been used in simulation. To predict the performance of the
proposed system, a MATLAB/SIMULINK based study has
been carried out for both AC and DC loads. The proposed
control scheme has shown very good voltage regulation and
phase balance even with unbalanced three-phase load.
Keywords: AC and DC load, Indirect vector control, PWM
inverter, Self-excited induction generator.
1
Introduction
The electrification of remote, rural areas are important for
the sustainable development of a country. To provide power
through grid extension becomes very difficult and expensive
in such hard to access and remote areas. In such areas, plenty
of renewable energy sources such as small hydro, wind, biomass etc. are available. A practical solution therefore is to
develop isolated, small-scale power generation schemes that
utilize the renewable energy resources locally available to
supply the consumers. Due to the research of clean power (or
renewable energy resources), and small-scale autonomous
power generation systems, the SEIG has become very popular
for generating power from renewable energy sources, such as
wind and small hydro. The SEIG has distinct advantages like
simplicity, low cost, ruggedness, little maintenance, absence
of DC, brushless etc. as compared to the conventional
synchronous generator. However, its major disadvantage is
the inability to control the voltage and frequency under
change in load and speed in stand-alone system.
A number of schemes have been suggested for regulating
the terminal voltage. The scheme based on switched
capacitors [1] finds limited application because it regulates
the terminal voltage in discrete steps. A saturable reactor
scheme of voltage regulator [2] involves a potentially large
size and weight, due to the necessity of a large saturating
inductor. In the short/long shunt configuration [3], the series
capacitor used causes the problem of resonance while
supplying power to an inductive load.
Unlike conventional excitation system that normally
consists of variable impedance scheme [4], the PWM
compensator permits the vector control implementation and
presents precise and continuous reactive power control with
fast response times, over a wide variation in speed. A wide
variety of VAR generators with some control strategies using
power electronic technology have been developed for standalone SEIG [5-7]. Lyra et al. [5] have analyzed a high
performance variable speed energy generation system based
on an isolated induction generator using a PWM VAR
compensator to control the flux in the induction generator and
the reactive power balance by implementing flux vector
control methods. Seyoum et al. [6] have presented the stator
flux oriented vector control for wind turbine driven isolated
induction generator. However, an additional decoupling
compensation should be applied for vector control in the
stator flux orientation. In [7], a field-oriented controller has
been used to excite the stand-alone induction machine
efficiently, minimizing copper and iron losses, and to regulate
the generated voltage for variable speed and load. An
advanced solution for voltage control of the induction
generator using rotor field-oriented control for small-scale AC
and DC power applications has been given by Ahmed et al.
[8]. Cardenas and Pena [9] have discussed a sensorless
control structure based on a direct rotor flux oriented vector
control system for variable speed wind energy applications.
The modeling, control system design and simulation results
for a stand-alone induction generator system with static
reactive power compensator of current controlled PWM VSI
using rotor flux oriented control has been presented by Liao
and Levi [10]. Ahmed et al. [11] have used a hybrid excitation
unit consisting of a capacitor bank and an active power filter
to regulate the output voltage of stand-alone SEIG and
proposed the advanced deadbeat current control strategy that
works with variable speed to reduce the system cost. Pucci
and Cirrincione [12] have presented a maximum power point
tracking for high performance wind generators. The fieldoriented control of the machine has been further integrated
with an intelligent sensorless technique.
Since, only few papers on application of vector control
techniques for control of SEIG are available in the literature,
further investigation on vector control of isolated induction
generators needs to be carried out. Accordingly, indirect
vector control strategy with rotor flux orientation with high
dynamic performance has been used in this paper for voltage
control of an isolated SEIG for both DC and AC power
applications. The single DC side capacitor provides all the
reactive current or the VAR required by the generator and the
load. The space-phasor model of the induction generator has
been used. The proposed scheme has been simulated in
MATLAB/SIMULINK environment. The simulated studies
for different transient conditions such as self-excitation,
sudden application and removal of both AC and DC loads
have been carried out to demonstrate the effectiveness of the
scheme.
2
System Description and Control
Scheme
Fig. 1 shows the general configuration of the system, where
the DC and AC loads can be supplied by the generator. The
basic system consists of a PWM VAR compensator connected
to an induction generator. A battery on the DC side of the
inverter is provided for initial excitation. When the flux
reaches the desired level, the battery is disconnected and the
generator supplies itself the necessary energy to control
the voltage across the compensator DC capacitor. The
reactive power required by the SEIG and load is provided by
the VSI.
During start-up, the power produced by SEIG is used to
charge the capacitor connected across the DC link to a set
reference value. In this study, the DC voltage is maintained at
600 V. The DC bus voltage is measured to feedback the DC
voltage controller. This controller provides the q-axis
component of compensator reference AC currents that
represents the flow of active power necessary to keep the DC
voltage constant. The field weakening is done above base
speed operation and the flux command is generated. The flux
error is fed to the PI controller and the output of this PI
controller gives the d-axis component of compensator
reference AC current. The principal vector control parameters
Idse* and Iqse* , which are DC values in synchronously rotating
frame, are converted to stationary frame with the help of unit
vectors (cosθe and sinθe). By using the transformation matrix,
the resulting stationary frame two axes current commands are
converted into three-phase current commands. These threephase current commands are compared with the three-phase
stator currents. The errors are amplified and compared with
the triangular carrier signal to generate the switching pulses
for the inverter.
Any variation in the output power of the SEIG is directly
indicated by the variation in the terminal voltage of the
generator. A reduction of the DC link voltage indicates that
the active power drawn by the load is more than the
generated power of the SEIG and the difference in power is
supplied by the VSI and hence, the DC link voltage falls.
An increase in the DC link voltage indicates that the active
power drawn by the load is less than the generated power
of the SEIG. In both these two cases, the controller varies
the ON-OFF period of the IGBTs of the inverter and the
terminal voltage of the generator is maintained constant.
Fig. 1. Block diagram of the proposed system.
i La
A
The shaft torque, Tshaft of the prime-mover and speed is
represented by a linear curve given as:
Tshaft = k1 – k2ωr
where, Tshaft is the shaft torque which shows the drooping
characteristic of prime-mover and k1 and k2 are constants. J is
the moment of inertia of the induction machine including the
machine (prime-mover) coupled on its shaft
i pa
L Lc
R La
i pc
3.2
R Lc
L Lb
L La
3.2.1
Rotor flux vector estimation
The derivations of the control equations of indirect
vector control can be done from the d-q equivalent circuit of
the induction machine in synchronously rotating reference.
The rotor circuit equations are written as:
R Lb
C
i Lc
i pb
B
i Lb
Fig. 2. Circuit diagram of three-phase inductive load
3
3.1
Mathematical Modeling
Modeling of the SEIG
The induction machine has been represented by the
space-phasor model. Instead of using two axes such as the d
and q for a balanced polyphase machine, the flux linkage
phasors can be thought of as being produced by equivalent
single-phase stator and rotor windings.
The four dq equations of equation (A1) in Appendix-A can be
reduced to two space-phasor equations as:
vs = vqs − jvds = (Rs + Ls p)is + Lm pir
(1)
Similarly, the rotor equations can be written as:
vr = vqr − jvdr = (Lm p − jωr Lm)is + (Rr + Lr p − jωr Lr )ir
(2)
From equations (A2) and (A3) in Appendix-A, the voltage
equations can be written as:
dλ s
Vs = Rs is +
dt
dλ
Vr = Rrir + r − jωr [B]λr
dt
where, V s = [vds vqs]T,
Vr = [0 0],
(3)
(4)
dλdre
+ Rr idre − (ωe − ωr )λqre = 0
dt
dλqre
+ Rr iqre + (ωe − ωr )λdre = 0
dt
where,
λdre = Lr idre + Lmidse
(9)
λ =Li +L i
e
qr
e
r qr
e
e
m qs
(10)
e
From (9) and (10), idr and iqr can be written as:
idre = (λdre − Lmidse )/Lr
(11)
iqre = (λqre − Lmiqse )/Lr
(12)
e
e
Eliminating idr and iqr from (7) and (8) using the equations
(11) and (12),
dλdre Rr e Lm
λdr −
+
Rr idse − ωsl λqre = 0
dt
Lr
Lr
dλqre
dt
+
(13)
Rr e Lm
λqr −
Rr iqse + ωsl λdre = 0
Lr
Lr
(14)
where ωsl = ωe − ωr .
e
qr
For decoupling control, λ
= 0, i.e.,
dλqre
dt
=0
From (13) and (14), we get
The electromagnetic torque developed is given by,
(5)
and
Lr dλr
+ λr = Lmidse
Rr dt
L R
ωsl = m r iqse
λr Lr
(15)
(16)
The derivative of rotor flux can be written as:
The torque balance equation of SEIG is defined as:
⎛2⎞
Tshaft = Te + J ⎜ ⎟ pωr
⎝ P⎠
(8)
λr = λdre .
⎡0 − 1⎤
Rs = diag[Rs Rs], Rr = diag[Rr Rr] and [B] = ⎢
⎥.
⎣1 0 ⎦
3P
Lm (iqs idr − ids iqr )
22
(7)
so that total rotor flux λr is directed along the de axis and
i s = [ids iqs]T,
i r = [idr iqr]T, λ s = [λds λqs]T, λr = [λdr λqr]T,
Te =
Modeling of the control scheme
pλr =
(6)
Rr
(Lmidse − λr )
Lr
The rotor flux is calculated from the above equation.
(17)
ω*sl can be written as:
L R *
ω*sl = m *r iqs
Lr λr
The slip frequency
and
(18)
ωe = ωr + ω*sl
(19)
The field angle (i.e., the angle of the synchronously rotating
frame) is calculated as:
θe = ∫ ωe dt
(20)
3.2.2
Calculation of d and q axes components of
compensator reference current
The field weakening is done above base speed operation
and accordingly the flux command (λrref) is generated. The
flux error at the nth sampling instant is expressed as :
λrer ( n ) = λrref ( n ) − λr ( n ) .
The flux error λrer is fed to the PI controller and the output of
the PI controller at the nth sampling instant is expressed as:
e* =I e*
Ids
(n) ds(n−1) +K pd {λrer(n) −λrer(n−1) }+Kidλrer(n)
(21)
where Kpd and Kid are the proportional and integral gain
constants, respectively, of the PI controller.
The DC bus voltage error (VDCer) at the nth sampling
instantis: VDCer(n) = VDCref(n) −VDC(n) . The error is fed to the
to generate the gate pulses. If the amplified error signal
corresponding to phase ‘a’ (Isaer) is greater than the triangular
carrier wave signal then the switch S1 (upper device) of the
phase ‘a’ leg of the VSI bridge is ON and the switch S4
(lower device) is OFF, and the value of the switching
function SA = 1. If the amplified error signal corresponding
to phase ‘a’ (Isaer) is less than the triangular carrier wave
signal then the switch S1 (upper device) is OFF and the
switch S4 (lower device) is ON, and SA = 0. Similar logic
applies to other phases.
3.2.5 Modeling of the VSI
The derivative of the DC bus voltage is defined as:
When there is no load on the DC side of the inverter,
pv dc = (i da SA + i db SB + i dc SC ) / C dc
and when DC load is present, the equation (27) is modified
as: pvdc = [(idaSA+ idbSB+ idcSC) − (
(+2 SA − SB − SC )
3
(− SA + 2SB − SC )
vb = Vdc
3
(− SA − SB + 2 SC )
vc = Vdc
3
v a = Vdc
(22)
where Kpq and Kiq are the proportional and integral gain
constants, respectively, of the DC bus PI controller.
3.2.3
Calculation of compensator reference currents in
stationary reference frame
The q-axis and d-axis reference currents ( I qs and I
e*
e*
ds
I ds* = − I qs sin θ e + I cosθ e
e*
e*
ds
(24)
These q and d axes stationary reference currents ( I qs* and
I ds* ) are converted to three phase reference currents
* , I * and I * ).
( I sa
sb
sc
3.2.4
The line voltages may be expressed as:
v ab = v a − vb = v dc (SA − SB)
vbc = vb − vc = v dc (SB − SC)
vca = v c − v a = v dc (SC − SA)
),
which are DC values in synchronously rotating frame, are
converted to stationary frame with the help of unit vectors as
given below:
(23)
I qs* = I qse* cos θ e + I dse* sin θ e
PWM current controller
* , I * and I * ) are compared
The reference currents ( I sa
sb
sc
with the sensed currents (Isa, Isb and Isc). The current errors
are amplified and compared with the triangular carrier wave
vdc
)]/ Cdc
Rd
(26)
where SA, SB and SC are the switching functions for the
ON/OFF positions of the VSI bridge switches S1-S6 and Rd is
the DC load resistance.
The DC bus voltage reflects at the output of the inverter in
the form of the three-phase PWM AC voltages va, vb and vc.
These voltages may be expressed as:
PI controller and the output of the PI controller for
maintaining DC bus voltage at the nth sampling instant is
given by
e* = I e*
I qs
( n ) qs ( n −1) + K pq {VDCer ( n ) −VDCer ( n −1) }+ KiqVDCer ( n )
(25)
3.3
(27)
(28)
(29)
Modeling of the load
3.3.1
DC load
The current through the DC load resistance connected
across the DC capacitor of the inverter is given by:
idc =
vdc
Rdc
(30)
3.3.2 Three phase resistive load
The phase currents ipa, ipb and ipc in the three-phase load
circuit are modeled as:
i pa =
vab
RLa
(31)
(32)
(35)
pi pc = (vca − RLc i pc )/LLc
(36)
From these phase currents of the load, the line currents of this
delta-connected load are given by:
iLa = i pa − i pc
(37)
iLb = i pa − i pc
(38)
iLc = i pa − i pc
(39)
0.4
0.6
0.8
0.2
0.4
0.6
0.8
Sudden application and removal of load
4.2.1 Load application and removal on DC side
To investigate the response of the system with sudden
application and removal of load on the DC side, the generator
is initially excited at no-load and suddenly a DC load of (Rdc =
5.6 p.u.) is applied at t = 1.2 sec. and this load is removed at t
= 1.8 sec. as shown in Fig. 5. At the time of application of
load, the voltages t end to decrease but quickly return to
1
1.2
1.4
1.6
1.8
2
1
1.2
Time (Sec.)
1.4
1.6
1.8
2
800
600
400
Cdc = 1000 Micro-farad
Cdc = 1500 Micro-farad
Cdc = 1800 Micro-farad
200
0
0
0.2
0.4
0.6
0.8
1
1.2
Time (Sec.)
1.4
1.6
1.8
2
Fig. 4. DC voltage build-up at no-load for different
values of capacitances.
0
-500
1
620
600
580
560
1
10
Isa (A)
Vdc (V)
Vsa (V)
500
1.2
1.4
1.6
1.8
2
2.2
2.4
1.2
1.4
1.6
1.8
2
2.2
2.4
-10
1
5
1.2
1.4
1.6
1.8
2
2.2
2.4
0
1
1.2
1.4
1.6
1.8
Time (Sec.)
2
2.2
2.4
0
Idc (A)
Self-excitation of the SEIG
The voltage build-up of the generator and the DC voltage
across the capacitor at no-load condition are shown in Fig. 3.
The reference DC voltage is set at 600 V. It is found that the
generator voltage remains small until the air-gap flux linkage
is at low level, and thereafter, there is a rapid growth of
voltage, which settles down to a steady-state value due to
magnetizing flux saturation. The DC voltage is settled to the
reference value. Fig. 4 gives the DC voltage build-up at noload with different values of capacitors. It is found that when
the capacitance value is large, it takes longer time to reach to
steady-state value.
4.2
0.2
800
600
400
200
0
0
Simulation results and discussion
The developed models have been simulated in
MATLAB/SIMULINK environment. The simulated results
have been presented for no-load excitation, sudden
application and removal of both AC and DC loads on a 2.2
kW, 3-phase, star connected induction machine. The
parameters of the induction machine obtained by conducting
DC resistance test, synchronous speed test and blocked rotor
test are given in Appendix B.
4.1
-500
0
Fig. 3. Voltage build-up at no-load.
Vdc (V)
pi pb = (vbc − RLb i pb )/LLb
0
Vdc (V)
(33)
3.3.3 Three phase inductive load
The derivatives of the phase currents of the delta connected
inductive load shown in Fig. 2 are given as:
pi pa = (vab − RLa i pa )/LLa
(34)
4
Vsa (V)
500
vbc
RLb
v
i pc = ca
RLc
i pb =
Fig. 5. Waveforms during application and removal
of load on DC side.
reference values. When the load is removed, the phase voltage
of the generator and the DC voltage increase due to mismatch
in active power produced by the SEIG, which is more than the
power consumed by the load. The duty cycle of the inverter is
adjusted by the control action and the voltages are maintained
at their reference values.
4.2.2 Load application and removal on AC side
To investigate the response of the system due to application
and removal of balanced resistive load across the terminals of
the SEIG, a resistive load (RL = 6.6 p.u./phase) is applied at t
= 1.4 sec. and removed at t = 2 sec. as shown in Fig. 6.
Vsa (V)
Vdc (V)
-500
1
650
550
1
10
6
Appendices
6.1
1.6
1.8
2
2.2
2.4
2.6
2.8
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
-10
1
5
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
1.2
1.4
1.6
1.8
2
Time (Sec.)
2.2
2.4
2.6
2.8
0
-5
1
Fig. 6. Stator phase ‘a’ voltage, DC voltage, stator
phase ‘a’ current and load current during application
and removal of resistive load on SEIG terminals.
Vdc (V)
Vsa (V)
500
0
-500
1.2
650
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
1.4
1.6
1.8
2
Time (Sec.)
2.2
2.4
2.6
2.8
600
Isa (A)
550
1.2
10
0
-10
1.2
5
0
-5
1.2
Fig. 7. Stator phase ‘a’ voltage, DC voltage, stator phase
‘a’ current and load current during application and
removal of inductive load on SEIG terminals.
Appendix A
The dq stationary reference frame model of the induction
machine is given by:
0
0 ⎤⎡iqs⎤
Lm p
⎡vqs⎤ ⎡Rs + Ls p
⎢v ⎥ ⎢ 0
0
Rs + Ls p
Lm p ⎥⎥⎢⎢ids⎥⎥
⎢ ds⎥ = ⎢
⎢vqr⎥ ⎢ Lm p
−ωr Lm Rr + Lr p −ωr Lr ⎥⎢iqr⎥
⎥⎢ ⎥
⎢ ⎥ ⎢
Lm p
ωr Lr Rr + Lr p⎦⎣idr⎦
⎣vdr⎦ ⎣ ωr Lm
1.4
0
Conclusions
This paper provides a high performance variable speed
induction generator system using indirect vector control
technique with rotor flux orientation for small-scale AC and
DC power applications. A PWM VAR compensator is used to
control the flux in the generator and the reactive power
balance. The excitation power is supplied from the capacitor
connected on the DC side of the PWM inverter. The induction
machine has been represented by space-phasor model. The
developed
models
have
been implemented using
MATLAB/SIMULINK. The controller has been tested for
different transient conditions such as voltage build-up, sudden
application and removal of both the resistive and the inductive
loads and also for unbalanced three-phase loads. It has a fast
dynamic response, robust, reliable and very good phase
balance even with unbalanced three-phase load.
1.2
600
Ipa (A)
5
0
Isa (A)
Figs. 8 and 9 show the three-phase load currents, stator
phase currents and stator phase voltages during sudden
application of unbalanced three-phase resistive load (RLa = 5.6
p.u., RLb = 6.76 p.u. and RLc = 7.5 p.u.) and inductive load
(RLa = 1.9 p.u., XLa = 1.4 p.u.; RLb = 2.8 p.u., XLb = 2.1 p.u.
and RLc = 3.8 p.u., XLc = 2.8 p.u.) respectively. It is observed
that stator phase voltages and currents are balanced even if the
load current is unbalanced due to the PWM inverter action.
Hence, the indirect vector control technique acts also as a
good phase balancer.
500
Ipa (A)
Similarly, the responses of the system due to load perturbation
with balanced inductive load (RL = 2.6 p.u./phase, XL = 1.97
p.u./phase) of 0.8 pf are shown in Fig. 7. In both these cases,
the voltage reduces during application and increases during
removal of load due to mismatch of power generated and
power consumed. The voltage comes to the reference value
quickly due to control action. The phase current of the SEIG
increases at the time of application of load.
(A1)
where Ls = Lls + Lm and Lr = Llr + Lm.
Again, in dq reference frame, the stator and rotor flux
linkages can be written as:
Lm ⎤⎡ids ⎤
⎡λds ⎤ ⎡Lls + Lm
⎢λ ⎥ = ⎢ L
Llr + Lm ⎥⎦⎢⎣idr ⎥⎦
⎣ dr ⎦ ⎣ m
Lm ⎤⎡iqs ⎤
⎡λqs ⎤ ⎡Lls + Lm
⎢ ⎥
⎢λ ⎥ = ⎢
Llr + Lm ⎥⎦⎣iqr ⎦
⎣ qr ⎦ ⎣ Lm
Lm ⎤
⎡ids ⎤ ⎡Lls + Lm
Hence, ⎢ ⎥ = ⎢
Llr + Lm ⎥⎦
⎣idr ⎦ ⎣ Lm
Lm ⎤
⎡iqs ⎤ ⎡Lls + Lm
Similarly, ⎢ ⎥ = ⎢
Llr + Lm ⎥⎦
⎣iqr ⎦ ⎣ Lm
−1
−1
⎡λds ⎤
⎢λ ⎥
⎣ dr ⎦
⎡λqs ⎤
⎢λ ⎥
⎣ qr ⎦
(A2)
(A3)
(A4)
(A5)
[2] S. M. Alghuwainem, “Steady-state analysis of a selfexcited induction generator self-regulated by shunt saturable
reactor”, IEEE International Conference on Electrical
Machines and Drives, pp. 101-103, 1997.
ILabc (A)
5
0
-5
1
1.1
1.2
1.3
1.4
1.5
1.6
Isabc (A)
10
0
-10
1
1.1
1.2
1.3
1.4
1.5
1.6
Vsabc (V)
500
0
-500
1
1.1
1.2
1.3
Time (Sec.)
1.4
1.5
1.6
ILabc (A)
5
0
1.4
1.6
1.8
2
2.2
2.4
Isabc (A)
10
0
-10
1.2
1.4
1.6
1.8
2
2.2
[4] M. B. Brennen and A. Abbondanti, “Static excitors for
induction generators”, IEEE Transactions on Industry
Applications, Vol. 1A-13, pp. 422-428, September-October
1977.
[5] R. O. C. Lyra, S. R. Silva and P. C. Cortizo, “Direct and
indirect flux control of an isolated induction generator”,
Proceedings of IEEE International Conference on Power
Electronics and Drive Systems, Vol. 1, pp. 140-145, 1995.
Fig. 8. Three-phase load currents, stator phase currents
and stator phase voltages during sudden application of
unbalanced resistive load on SEIG terminals.
-5
1.2
[3] S. S. Murthy, C. Prabhu, A. K. tandon and M. O.
Vaishya, “Analysis of series compensated self-excited
induction generators for autonomous power generation”,
IEEE Conference on Power Electronics, Drives and Energy
Systems for Industrial Growth, pp. 687-693, 1996.
2.4
[6] D. Seyoum, M. F. Rahman and C. Grantham, “Terminal
voltage control of a wind turbine driven isolated induction
generator using stator oriented field control”, Proceedings of
IEEE Power Electronics Conference and Exposition- APEC,
Vol. 2, pp. 846-852, 2003.
[7] R. Leidhold, G. Garcia and M I. Valla, “Field-oriented
controlled induction generator with loss minimization”, IEEE
Transactions on Industrial Electronics, Vol. 49, No. 1, pp.
147-156, February 2002.
Vsabc (V)
500
0
-500
1.2
1.4
1.6
1.8
Time (Sec.)
2
2.2
2.4
Fig. 9. Three-phase load currents, stator phase currents
and stator phase voltages during sudden application of
unbalanced inductive load on SEIG terminals.
6.2
Appendix B
The parameters of the induction machine are given as:
2.2 kW, 3-phase, 4-pole, 50 Hz, 415 V., 4.5 A., star
connected, 1440 rpm, Rs = 3.84 Ω, Rr = 2.88 Ω, Xls = 4.46 Ω,
Xlr = 4.46 Ω, Lm = 0.2168 H, Base impedance = 53.24 Ω.
Coefficients of the Prime-mover Characteristics:
k1 = 249.39, k2 = 0.7875
7
References
[1] N. H. Malik and A. H. Al-Bahrani, “Influence of the
terminal capacitor on the performance characteristics of a
self-excited induction generator”, IEE Proceedings, Part C,
Vol. 137, No. 2, pp. 168-173, march 1990.
[8] T. Ahmed, K. Nishida and M. Nakaoka, “Advanced
voltage control of induction generator using rotor fieldoriented control”, Conference Record of IEEE Industry
Applications Conference, Vol. 4, pp. 2835-2842, 2-6
October, 2005.
[9] Cardenas R. and Pena R., “Sensorless vector control of
induction machines for variable speed wind energy
applications”, IEEE Trans. on Energy Conversion, Vol. 19,
No. 1, pp. 196-205, 2004.
[10] Liao Y. W. and Levi E., “Modelling and simulation of a
stand-alone induction generator with rotor flux oriented
control”, Electric Power Systems Research, Vol. 46, pp. 141152, 1998.
[11] T. Ahmed, K. Nishida and M. Nakaoka, “A novel standalone induction generator system for AC and DC poer
applications”, IEEE Transactions on Industry Applications,
Vol. 43, No. 6, pp. 1465-1474, November/December 2007.
[12] M. Pucci and M. Cirrincione, “Neural MPPT control of
wind generators with induction machines without speed
sensors”, IEEE Transactions on Industrial Electronics, Vol.
58, No. 1, pp. 147-156, January 2011.