IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 15, NO. 3, MAY 2000
495
An Improved Control Algorithm of Shunt Active
Filter for Voltage Regulation, Harmonic Elimination,
Power-Factor Correction, and Balancing of Nonlinear
Loads
Ambrish Chandra, Senior Member, IEEE, Bhim Singh, B. N. Singh, Member, IEEE, and
Kamal Al-Haddad, Senior Member, IEEE
Abstract—This paper deals with an implementation of a
new control algorithm for a three-phase shunt active filter to
regulate load terminal voltage, eliminate harmonics, correct
supply power-factor, and balance the nonlinear unbalanced loads.
A three-phase insulated gate bipolar transistor (IGBT) based
current controlled voltage source inverter (CC-VSI) with a dc bus
capacitor is used as an active filter (AF). The control algorithm
of the AF uses two closed loop PI controllers. The dc bus voltage
of the AF and three-phase supply voltages are used as feed back
signals in the PI controllers. The control algorithm of the AF provides three-phase reference supply currents. A carrier wave pulse
width modulation (PWM) current controller is employed over the
reference and sensed supply currents to generate gating pulses
of IGBT’s of the AF. Test results are presented and discussed
to demonstrate the voltage regulation, harmonic elimination,
power-factor correction and load balancing capabilities of the AF
system.
Fig. 1. Fundamental building block of the active filter.
Index Terms—Active filter, harmonic compensation, load balancing, power-factor correction, voltage regulation.
I. INTRODUCTION
S
OLID state control of ac power using thyristors and other
semiconductor devices is in an extensive use in a number of
applications such as adjustable speed drives (ASD’s), furnaces,
computers power supplies, and asynchronous ac–dc–ac links.
These power converters behave as nonlinear loads to ac supply
system and cause harmonic injection, lower power-factor, poor
voltage regulation, and utilization of ac network. Moreover, in
a three-phase ac system some load unbalancing may be present
due to the use of some typical loads such as traction and furnaces. Single-phase loads on a three-phase supply system result
in an unbalance in system voltage and supply current. The unbalance in the voltage affects the performance of other loads,
Manuscript received November 11, 1998; revised January 18, 1999. This
work was supported by the Natural Science and Engineering Research Council
of Canada. Recommended by Associate Editor, F. D. Tan.
A. Chandra, and K. Al-Haddad are with the Department of Electrical Engineering. Ecole de Technologie Supérieure GREPCI, Montreal, Quebec H3C
1K3, Canada.
B. Singh is with the Department of Electrical Engineering. Indian Institute of
Technology Hauz Khas, New Delhi 110016 India.
B. N. Singh is with the Department of Electrical Engineering and Computer
Science, Tulane University, New Orleans, LA 70118 USA.
Publisher Item Identifier S 0885-8993(00)03394-9.
Fig. 2.
Control scheme of the active filter.
0885-8993/00$10.00 © 2000 IEEE
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IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 15, NO. 3, MAY 2000
capacitor is used as the shunt AF. An indirect current control
technique [28] is employed to obtain PWM switching signals for
the devices used in the CC-VSI working as an AF. Three-phase
reference supply currents are derived using sensed ac voltages
(at PCC) and dc bus voltage of the AF as feedback signals. Two
proportional plus integral (PI) controllers are used to estimate
the amplitudes of in-phase and quadrature components of reference supply currents. The control algorithm of the AF is implemented on a TMS320C31 DSP system. Test results during
steady state and transient operating conditions of the AF are
presented and discussed in detail to demonstrate voltage regulation/power-factor correction, harmonic elimination and load
balancing capabilities of the AF system.
II. SYSTEM CONFIGURATION AND CONTROL SCHEME
Fig. 3. Digital signal processing (DSP) system hardware of the active filter.
mainly the cage induction motors. In the past, a number of attempts have been made [1]–[28] on harmonic elimination, load
balancing and power factor correction.
Several texts [2], [6], [9], [10], [21], [22] have appeared on
electric power quality and many solutions have been suggested
to improve the power quality. A number of compensators have
been reported only for load balancing [2], [3], [5], [7], [11],
[13], [19], [20] using lossless passive elements (L and C) and
active elements (solid state CSI and VSI). Similarly, several attempts have been made only for harmonic elimination [1], [4],
[6], [8]–[10], [12], [14]–[28] using passive, active and hybrid
filters to improve the performance and to reduce the size of an
active filter. Many control techniques such as instantaneous reactive power theory [4], notch filters [16], flux based controller
[17], power balance theory [18]–[20], sliding mode controllers
[14], [15] etc. have been used to improve the performance of the
active and hybrid filters. Most of these control algorithms need a
number of transformations and are difficult to implement. Apart
from the problems of harmonics, poor power-factor and unbalance, there is some voltage drop at the point of common coupling (PCC) due to reactive power burden of nonlinear loads.
This paper presents an implementation of a simple and new
control algorithm of a shunt active filter (AF) for ac voltage
regulation at load terminals (at PCC), harmonic elimination,
power-factor correction and load balancing of nonlinear loads.
The control algorithm of the AF is made flexible and it can be
modified for power-factor correction (unity), harmonic elimination and load balancing of nonlinear loads. The proposed control algorithm inherently provides a self-supporting dc bus of
the AF. An insulated gate bipolar transistor (IGBT) based current controlled voltage source inverter (CC-VSI) with a dc bus
Fig. 1 shows the fundamental building block of the shunt AF.
The AF system is made of a standard three-phase IGBT based
) and a dc bus
VSI bridge with the input ac inductors ( ,
) to obtain a self-supporting dc bus for an effeccapacitor (
tive current control. A three-phase ac mains with line impedance
) is feeding power to a three-phase diode bridge recti( ,
fier with a resistive-inductive load. A provision is made with a
switch to open an ac line of the load to realize an unbalanced
nonlinear load. The values of circuit parameters of the system
are given in the Appendix.
Fig. 2 shows the control scheme of the AF. Three-phase voltages at PCC along with dc bus voltage of the AF are used for
implementation of control scheme. In real time implementation of the AF a band pass filter plays an important role. The
three-phase voltages ( , , and ) are sensed at PCC (Fig. 1)
using potential transformers and conditioned in a band pass filter
to meet the range of ADC channels and to filter out any distortion. The three-phase voltages ( , , and ) are inputs
, and
) are outand three-phase filtered voltages ( ,
, and
) here
puts from band pass filter. The voltages ( ,
in after are termed as the supply voltages. In real time control of the AF, a self-supporting dc bus of the AF is realized
using a PI controller over the sensed ( ) and reference ( )
values of dc bus voltage of the AF. The PI voltage controller on
of
the dc bus voltage of the AF provides the amplitude
, and
) of reference supply
in-phase components (
,
, and
currents. The three-phase unit current vectors (
) are derived in-phase with the supply voltages ( ,
,
). Another PI controller is used over the reference
and
and sensed ( ) values of peak supply voltage. The output of
of quadrathis PI controller is considered as an amplitude
, and
) of reference supply curture components (
,
rents. The three-phase quadrature unit current vectors (
, and
) are derived from in-phase unit current vectors
,
, and
). The multiplication of in-phase ampli(
with in-phase unit current vectors (
,
, and
tude
) results in the in-phase components (
,
, and
) of
three-phase reference supply currents ( , , and ). Simiwith quadralarly, multiplication of quadrature amplitude
,
, and
) results in the
ture unit current vectors (
,
, and
)
quadrature components (
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CHANDRA et al.: IMPROVED CONTROL ALGORITHM OF SHUNT ACTIVE FILTER
Fig. 4.
497
Performance of the AF system under switch IN and steady state conditions with a three-phase nonlinear load.
Fig. 5. Steady state response of the AF for voltage regulation and harmonic elimination with a three-phase nonlinear load.
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498
IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 15, NO. 3, MAY 2000
Fig. 6. Steady state response of the AF for voltage regulation, harmonic elimination, and load balancing with a single-phase nonlinear load.
of three-phase reference supply currents ( , , and ). Alge,
, and
) and quadrature (
,
braic sum of in-phase (
, and
) components results in the three-phase reference
supply currents ( , , and ). For regulation of voltage at
PCC the three-phase reference supply currents have two components. The first component is in-phase with the voltage at PCC
to feed active power to the load and the losses of the AF. The
second component is at quadrature with the voltage at PCC to
feed reactive power of load and to compensate the line voltage
drop by reactive power injection at the PCC. For power-factor
correction to the unity, harmonic elimination and balancing of
nonlinear load, the quadrature component of reference supply
currents is set to zero by assigning a zero value to the quantity
. For the voltage regulation at PCC, the supply currents
should lead the supply voltages while for the power factor control to the unity, the supply currents should be in phase with
the supply voltages. Since these two conditions, namely, voltage
regulation at PCC and power-factor control to unity can not be
achieved simultaneously [2], therefore, the control algorithm
of the AF is made flexible to achieve either voltage regulation, harmonics compensation, load balancing or power-factor
correction to unity, harmonics compensation, load balancing.
With three-phase supply voltages ( ,
, and
) and dc bus
voltage ( ) as feedback signals, the control algorithm of the
AF provides the three-phase reference supply currents ( , ,
and ) as output signals. A carrier wave PWM current controller is used over reference supply currents ( , , and )
and sensed supply currents ( , , and ) to generate gating
signals to the IGBT’s used in the VSI bridge working as the AF.
In response to gating pulses to the AF, it regulates the voltage
at PCC, eliminates harmonics, correct the power-factor at PCC
and balances the unbalanced nonlinear load while maintaining
a self-supporting dc bus of the AF. A deadbeat time of 8 s is
set between upper and lower devices of a leg of VSI to avoid
shoot through fault. An over current protection of devices of the
AF is provided at gate drive level of each IGBT to ensure a safe
operation of the VSI. The carrier frequency of PWM controller
is set at 6.4 kHz.
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CHANDRA et al.: IMPROVED CONTROL ALGORITHM OF SHUNT ACTIVE FILTER
Fig. 7.
499
Switch IN response of the AF for voltage regulation, harmonic elimination with a three-phase nonlinear load.
III. DSP HARDWARE AND CONTROL ALGORITHM
In this section, the details of hardware interfacing with DSP
system and basic equations of control algorithm are given.
A. Description of DSP System Hardware
Fig. 3 shows the DSP system hardware of the AF. The DSP
system [29] consists of a TSM320C31 digital signal processor,
eight channels of 12 bit analog to digital converter (ADC), eight
channels of 12-bit digital to analog converter (DAC), three
hardware interrupts and three timer interrupts. The DSP system
is serially interfaced to an IBM-PC. In PC the control algorithm
is developed in C language and converted in assembly language
codes using optimizing compiler. These assembly language
codes are down loaded into the DSP board through serial port.
, and
) and dc
The three-phase supply voltages ( ,
bus voltage ( ) of the AF are input signals to the DSP board
through its ADC interface. The dc bus voltage of the AF is
sensed using an isolation amplifier (AD202) and scaled to feed
to ADC channel. The synchronization of ac mains with the control algorithm in DSP system is obtained using one digital signal
(hardware interrupt). This signal is generated using comparators and logic gates over the three-phase ac supply voltages.
The three-phase ac supply voltages result in six zero crossing
signals at 60 of intervals. Therefore, the digital signal continuously interrupts the DSP system at 60 time intervals of frequency of ac supply system. Using four analog signals and one
hardware interrupt signal, the control algorithm of the AF is implemented in real time. The control algorithm of the AF generates three-phase reference supply currents. The three-phase
reference supply currents ( , , and ) are input signals to
DAC’s of DSP. The outputs of DAC’s are fed to a carrier wave
PWM current controller. In PWM current controller the error
signals of the reference ( , , and ) and sensed ( , ,
and ) supply currents (sensed using LEM hall-effect current
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IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 15, NO. 3, MAY 2000
Fig. 8. Switch IN response of the AF for voltage regulation, harmonic elimination and load balancing with a single-phase nonlinear load.
sensors) are compared with a carrier signals resulting in gating
pulses for the IGBT’s of the AF.
The error signal,
, is processed in PI controller and output
at th sampling instant is expressed as
B. Basic Equations of Control Algorithm of the AF
The three-phase reference supply currents are computed
using three-phase supply voltages and dc bus voltage of the AF.
These reference supply currents consist of two components, one
in-phase and another in quadrature with the supply voltages.
1) Computation of In-Phase Components of Reference
of in-phase component
Supply Currents: The amplitude
of reference supply currents is computed using PI controller
) of the AF and
over the average value of dc bus voltage (
. Comparison of average and
its reference counterpart
reference values of dc bus voltage of the AF results in a voltage
, at th sampling instant
error, which is expressed as,
(1)
(2)
and
are proportional and integral gains of
where
and
the dc bus voltage PI controller. The quantities,
are the output of the voltage controller and voltage
th sampling instant. The output
error, respectively, at
of PI controller is taken as amplitude
of in-phase
component of the reference supply currents.
Three-phase in-phase components of the reference supply
and in-phase
currents are computed using their amplitude
unit current vectors derived in-phase with the supply voltages
and
(3)
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CHANDRA et al.: IMPROVED CONTROL ALGORITHM OF SHUNT ACTIVE FILTER
501
Fig. 9. Dynamic response of the AF for voltage regulation, harmonic elimination, and load balancing under the load change from three-phase to single-phase.
Fig. 10.
Dynamic response of the AF for voltage regulation, harmonic elimination, and load balancing under the load change from single-phase to three-phase.
where
,
derived as
, and
are in-phase unit current vectors and
and
where
as
(4)
PI controller over the average value of amplitude (
) of
. Comparison
supply voltage and its reference counterpart
of average and reference values of amplitude of the supply
,
voltage results in a voltage error, which is expressed as,
at th sampling instant
is the amplitude of supply voltage and it is computed
(6)
(5)
2) Computation of Quadrature Components of Reference
of quadrature compoSupply Currents: The amplitude
nent of reference supply currents is computed using an another
, is processed in PI controller and
The error signal,
at th sampling instant is expressed as
output
(7)
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502
IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 15, NO. 3, MAY 2000
Fig. 11. Steady state response of the AF for power-factor correction, harmonic elimination with a three-phase nonlinear load.
where
and
are proportional and integral gain conand
stants of ac voltage PI controller. The quantities,
are the output of voltage controller and voltage error,
)th sampling instant. The output
respectively, at (
of PI controller is taken as amplitude
of quadrature component of the reference supply currents. Three-phase quadrature
components of the reference supply currents are computed using
and quadrature unit current vectors as
their amplitude
and
(8)
,
, and
are quadrature unit current vectors
where
and these are derived from in-phase unit current vectors as
(9)
3) Computation of Total Reference Supply Currents: Threephase instantaneous reference supply currents are computed by
adding in-phase and quadrature components expressed in (3)
and (8)
(10)
For ac voltage regulation along with harmonic elimination
and load balancing these reference supply currents are used
directly. However, for power-factor correction along with
of
harmonic elimination and load balancing, amplitude
,
, and
) is set to zero and
quadrature components (
,
, and
)
in this condition the in-phase components (
become the total reference supply currents ( , , and ).
However, by giving a proper weight-age to two components of
reference supply currents a reasonably good compromise may
be achieved.
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CHANDRA et al.: IMPROVED CONTROL ALGORITHM OF SHUNT ACTIVE FILTER
503
Fig. 12. Steady state response of the AF for power-factor correction, harmonic elimination, and load balancing with a single-phase nonlinear load.
The three-phase reference supply currents ( , , and )
are inputs to 12 bit DAC’s of DSP and outputs of DAC’s are fed
to PWM current controller along with sensed supply currents
( , , and ). The PWM current controller generates gating
signals for IGBT’s of the AF.
IV. PERFORMANCE OF THE AF SYSTEM
A number of tests have been carried out on the developed
prototype model of the AF system for voltage regulation and
power-factor correction along with load balancing and harmonic
elimination. Test results on the AF are presented in Figs. 4–14
and Tables I and II, demonstrating its steady state and transient
performance. From these results, the following observations are
made.
A. Effect of the AF on Power Quality
To demonstrate voltage regulation capability of the AF, an
inductor ( and , values are given in the Appendix) is intro-
duced in each phase in series with the line connecting ac mains
with the AF and load. This causes a voltage drop and distortion
in the voltage waveforms ( , , and ) at PCC as shown in
Fig. 4 for the phase a ( ). Fig. 4(a) shows “switch-in” response
of the AF, whereas, Fig. 4(b) shows steady state response of the
AF with a three-phase nonlinear load. In Fig. 4(a), all the quantities are shown for phase “ ” only and top to bottom waveforms
), load voltage at the PCC ( ),
are the mains voltage (
supply voltage ( ) obtained from load voltage ( ) using a
band pass filter and supply current ( ). It is to mention here
that the supply voltage ( ) is recorded in the results pertaining
to all other operating conditions of the AF system. It is observed
from Fig. 4 that the load terminal voltage ( ) is quite distorted
and has a THD of 18.3% without AF, however, its THD reduces
to 4.3% when the AF is switched in. A comparative reduction
in different harmonics present in load terminal voltage ( ) are
given in Table I. Similarly, THD in supply currents also reduces
to 4.2% from 27.4% when the AF is “switched-in.” Table II
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504
Fig. 13.
IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 15, NO. 3, MAY 2000
Switch IN response of the AF for power-factor correction and harmonic elimination with a three-phase nonlinear load.
presents various harmonics in the supply current for the cases
with and without compensation. The high frequency switching
ripples which are observed in the load voltage ( ) are filtered
out with the help of a band pass filter and output of band pass
fed to DSP system. The results shown
filter is voltage signal
in Fig. 4 and Tables I and II confirm that the AF system is able
to improve the quality of power and reduces THD in the voltage
(4.3% THD) and current (4.2% THD) at PCC.
) are sinusoidal, balanced and slightly leading with respect to
, and
) which is necessary to comsupply voltages ( ,
pensate line impedance drop. Fig. 6 shows the steady state response of the AF for voltage regulation, harmonic elimination
and load balancing with a single-phase nonlinear load. The AF
regulates the ac load terminal voltage, eliminates harmonics and
balances a single-phase load resulting in three-phase balanced,
sinusoidal and slightly leading power-factor supply currents.
B. Steady State Performance of the AF for Voltage Regulation,
Harmonic Elimination, and Load Balancing
C. Dynamic Response of the AF for Voltage Regulation,
Harmonic Elimination, and Load Balancing
Fig. 5 shows the steady state response of the AF for ac voltage
regulation and harmonic elimination with a three-phase nonlinear load. The AF system regulates ac load terminal voltage
at its reference value and reduces THD in the supply current to
4.2% from 27.4% THD in load current. The dc bus voltage of the
AF is also regulated at its reference value and thus a self-supporting dc bus is obtained. The supply currents ( , , and
Fig. 7 shows the “switch-in” response of the AF for voltage
regulation, harmonic elimination and load balancing with a
three-phase nonlinear load. It is observed that the ac load
terminal voltage is raised from 37.48 V (rms) to its reference
value set at 40 V (rms). With the AF system switched in, the
supply currents become sinusoidal within a fraction of a cycle
of ac mains. The dc bus voltage reaches to its steady state
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CHANDRA et al.: IMPROVED CONTROL ALGORITHM OF SHUNT ACTIVE FILTER
Fig. 14.
505
Switch IN response of the AF for power-factor correction, harmonic elimination, and load balancing with a single-phase nonlinear load.
value almost instantaneously due to fast dynamic response of
the AF system. Fig. 8 shows the “switch-in” response of the
AF with a single-phase nonlinear load. The supply currents
become sinusoidal and balanced almost instantaneously which
confirms fast response of the AF. The ac load terminal voltage
and dc bus voltage of the AF reach to their respective desired
values within a cycle of the ac mains.
Fig. 9 shows the dynamic response of the AF for a load
change from three-phase to single-phase. The ac load terminal
voltage remains unaffected and the supply currents are reduced
in amplitude but remain sinusoidal, balanced and slightly
leading with respect to supply voltages. Similarly, Fig. 10
shows the dynamic response of the AF when a single-phase
nonlinear load is changed to a three-phase. The three-phase
supply currents are observed with an increased amplitude but
remain sinusoidal, balanced and slightly leading with respect to
supply voltage which is necessary to regulate ac load terminal
voltage.
D. Steady State Performance of the AF for Power-Factor
Correction, Harmonic Elimination, and Load Balancing
Fig. 11 shows the steady state response of the AF with a
three-phase nonlinear load for power-factor correction and harmonic elimination. The AF is able to reduce harmonics in the
supply currents (THD 4.0% from 27.4%) and it improves the
supply power-factor to unity. The supply currents are balanced,
sinusoidal and in-phase with the voltages. Fig. 12 shows the
steady state response of the AF with a single-phase nonlinear
load. It is observed that the AF is able to balance a nonlinear
single-phase load resulting in sinusoidal, balanced and unity
power-factor supply currents. The control algorithm also provides a self-supporting dc bus of the AF.
E. Dynamic Performance of the AF for Power-Factor
Correction, Harmonic Elimination, and Load Balancing
Fig. 13 shows “switch-in” response of the AF with a threephase nonlinear load for power-factor correction and harmonic
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IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 15, NO. 3, MAY 2000
TABLE I
CONTENT OF HARMONICS IN LOAD
VOLTAGE (EXPERIMENTAL RESULTS)
TABLE II
CONTENT OF HARMONICS IN SUPPLY CURRENTS (EXPERIMENTAL RESULTS)
linear loads. Dynamic and steady state performances of the AF
system have been observed under different operating conditions
of the load. The performance of the AF system has been found
to be excellent. The AF system has been found capable of improving the power quality, voltage profile, power-factor correction, harmonic elimination and balancing the nonlinear loads.
The proposed control algorithm of the AF has an inherent property to provide a self-supporting dc bus and requires less number
of current sensors resulting in an over all cost reduction. It has
been found that for voltage regulation and power-factor correction to unity are two different things and can not be achieved
simultaneously. However, a proper weight-age to in-phase and
quadrature components of the supply current can provide a reasonably good level of performance and voltage at PCC can be
regulated with a leading power-factor near to unity. It has been
found that the AF system reduces harmonics in the voltage at
PCC and the supply currents well below the mark of 5% specified in IEEE-519 standard.
APPENDIX
A. System Parameters
(rms/phase)
mH,
and
V,
F,
,
Hz,
,
,
mH,
mH.
B. PI Controllers Gain Constants
1) DC Bus Voltage PI Controller:
.
2) AC Voltage PI Controller:
.
elimination. The AF system offers an instantaneous response
and moment it is turned on it starts filtering the nonsinusoidal
load currents resulting in balanced, sinusoidal and unity powerfactor supply currents. The dc bus voltage of the AF is maintained at its reference value and thus a self-supporting dc bus
is obtained. Fig. 14 shows “switch-in” response of the AF with
a single-phase nonlinear load. The supply currents become balanced, sinusoidal and in phase with the supply voltages resulting
in unity power-factor of ac mains. The phase “a” current of the
AF is same as the supply current because there is no load on this
phase. The dc bus voltage of the AF is regulated at its reference
value.
The proposed control algorithm of the AF is found suitable
to regulate ac load voltage, to correct the power-factor of ac
mains to unity and harmonic reduction in the supply currents
and terminal voltages along with load balancing. The proposed
AF with an indirect current control technique applied over the
sensed and reference supply currents reduces real time computation effort and requires a less number of current sensors. These
aspects enhance the response of the AF due to processing of less
number of signals and reduce the overall cost of the system.
V. CONCLUSIONS
An improved control algorithm of the AF system has been implemented on a DSP system for voltage regulation/power-factor
correction, harmonic elimination and load balancing of non-
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1992.
Ambrish Chandra (SM’87) was born in India
in 1955. He received the B.E. degree from the
University of Roorkee, India, in 1977, the M.Tech.
degree from I.I.T., New Delhi, India, in 1980, and
the Ph.D. degree from the University of Calgary,
Calgary, Alta., Canada, in 1987.
He worked as a Lecturer and later as a Reader
at the University of Roorkee. He is a Professor in
the Electrical Engineering Department, Ecole de
Technologie Supérieure, Montreal, Que., Canada.
His main research interests are power quality, active
filters, reactive power compensation, and FACTS.
507
Bhim Singh was born in Rahamapur, U.P., India
in 1956. He received the B.E. degree from the
University of Roorkee, India, in 1977 and the
M.Tech. and Ph.D. degrees from the Indian Institute
of Technology (IIT), New Delhi, in 1979 and 1983,
respectively.
In 1983, he started working as a Lecturer and,
in 1988 became a Reader in the Department of
Electrical Engineering, University of Roorkee.
In December 1990, he started as an Assistant
Professor, became an Associate Professor in the
Department of Electrical Engineering, IIT, in 1994, and a Professor in 1997.
His field of interest includes CAD, power electronics, active filters, static VAR
compensation, analysis, and digital control of electrical machines.
Dr. Singh is a Fellow of IE(I) and IETE and a Life Member of ISTE, SSI, and
NIQR.
B. N. Singh (M’98) was born in 1968. He received
the B.E. degree from M.M.M. Engineering College,
Gorakhpur, India, in 1989, the M.E. degree from the
University of Roorkee, India, in 1991, and the Ph.D.
degree from Indian Institute of Technology, New
Delhi, in 1996.
In September 1996, he joined the Department
of Electrical Engineering, École de Technologie
Supérieure, Montréal, P.Q., Canada, as a Postdoctoral Fellow, where he worked in the area of active
filters, UPFC, and FACTS. In February 1999, he
joined the Department of Electrical and Computer Engineering, Concordia
University, Montreal, as a Research Fellow, where he worked in the area of
power supplies for telecommunication system. Recently, he joined the Department of Electrical Engineering and Computer Science, Tulane University, New
Orleans, LA, as an Assistant Professor. His main research interests are power
supplies, power electronics, power systems, electrical machines, and drives.
Kamal Al-Haddad (S’82–M’88–SM’92) was born
in Beirut, Lebanon, in 1954. He received the B.Sc.A.
and the M.Sc.A. degrees from the Université du
Québec à Trois-Rivières, P.Q., Canada, in 1982 and
1984, respectively, and the Ph.D. degree from the
Institut National Polytechnique, Toulouse, France,
in 1988.
From June 1987 to June 1990, he was a Professor
in the Engineering Department, Université du
Québec, Trois-Rivières. In June 1990, he joined
the teaching staff as a Professor in the Electrical
Engineering Department, École de Technologie Supérieure, Université du
Québec, Montreal, P.Q. His fields of interest are static power converters,
harmonics, and reactive power control, switch mode and resonant converters,
including the modeling, control, and development of industrial prototypes for
various applications.
Dr. Al-Haddad is a member of the Order of Engineering of Québec and the
Canadian Institute of Engineers.
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