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IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, VOL. 1, NO. 3, OCTOBER 2010
Comparison of Directly Connected and Constant
Voltage Controlled Photovoltaic Pumping Systems
Mohammed Ali Elgendy, Bashar Zahawi, Senior Member, IEEE, and David John Atkinson
Abstract—This paper presents a comparative investigation of the
performance characteristics of a directly connected photovoltaic
(PV) pumping system and a scheme utilizing a constant voltage
maximum power point tracking algorithm. A simple and accurate
model is developed for each individual component of the system
based on its measured characteristics and the system is simulated
numerically. System performance is analyzed and energy utilization efficiency is calculated for different weather conditions. A detailed comparison identifying the advantages and drawbacks of
each technique is presented. Experimental results obtained using
a 1080-Wp PV array connected to a 1-kW permanent magnet dc
motor-centrifugal pump set show very good agreement with the
numerical simulation of the systems.
Index Terms—DC–DC power conversion, photovoltaic (PV)
power systems, photovoltaic (PV) pumping.
I. INTRODUCTION
O
NE of the most important applications of photovoltaic
(PV) standalone systems is for water pumping, particularly in rural areas that have a considerable amount of solar radiation and have no access to national grids. PV pumping systems
usually utilize low power pumps ranging from 200–2000 W.
They are widely used in domestic and livestock water supplies
and small-scale irrigation systems, especially those employed
for water and energy conservation such as low head drip irrigation systems. Over 50 000 PV pumping systems made up of
different configurations had been installed worldwide by 2007
with an increasing potential for the use of PV pumping systems
in large-scale irrigation schemes [1].
Several types of pumps and motors are available on the PV
pumping market. The most commonly employed pump type
is the centrifugal pump. Single-stage centrifugal pumps are
frequently used in PV shallow water pumping for low head
applications. For PV subterranean water pumping and surface
water pumping with higher heads, multistage centrifugal pumps
are more suitable. Other pump types such as progressive cavity
pumps [2] and piston pumps [3] have also been utilized.
The most commonly utilized motor type with PV pumping
systems is the permanent magnet (PM) brushed dc motor
[4]–[8]. Other brushed dc motors such as series [9], shunt [10],
Manuscript received February 17, 2010; revised April 30, 2010; accepted
June 06, 2010. Date of publication June 14, 2010; date of current version
September 22, 2010.
The authors are with the School of Electrical, Electronic, and Computer Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K. (e-mail:
m.a.elgendy@ncl.ac.uk; bashar.zahawi@ncl.ac.uk; dave.atkinson@ncl.ac.uk).
Color versions of one or more of the figures in this paper are available online
at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TSTE.2010.2052936
Fig. 1. Mismatch between motor-pump load and PV generator. (a) I –V curves;
(b) power–voltage curves.
and separately excited [11] motors have also been investigated.
In bore-hole and deep-well pumping applications, induction
motors [12] and brushless dc motors [2] are preferred since
they require less maintenance. Other types of motors have also
been used including single-phase induction motors [13] and
switched reluctance motors [14].
A dc motor-pump set can be connected directly to the PV
generator as is the case with most commercial dc PV pumping
systems. In this case, the system operates at the intersection of
the current–voltage ( – ) curve of the PV generator and the
load-line, as shown in Fig. 1. This operating point may be far
from the maximum power point (MPP) of the PV generator
wasting a significant part of the available solar power.
To better match the PV generator to the motor-pump set, a
pump controller is required. For dc PV pumping systems, the
pump controller is basically a dc–dc converter whose duty ratio
is controlled by a maximum power point tracking (MPPT) algorithm. This is used to adjust the motor armature voltage and
1949-3029/$26.00 © 2010 IEEE
ELGENDY et al.: COMPARISON OF DIRECTLY CONNECTED AND CONSTANT VOLTAGE CONTROLLED PV PUMPING SYSTEMS
185
Fig. 2. SANYO’s HIP-J54BE2 PV array.
in turn the motor speed and the hydraulic power of the pump
according to the insolation level. Different types of dc–dc converters have been employed including the buck converter [8],
[15] and the boost converter [4] depending on the voltage rating
of the motor and the PV array.
A constant voltage MPPT algorithm assumes a fixed value
for the MPP voltage equal to the value measured at standard
test conditions provided by the manufacturer. This value is used
as a reference for a feedback control loop that usually employs
a PI controller to adjust the duty ratio of an MPPT converter.
Constant voltage MPPT control requires the measurement of the
array voltage only and is easily implemented with both analogue
and digital circuits.
In this paper, a directly connected PV pumping system and
a scheme utilizing a constant voltage MPPT algorithm are examined experimentally using a 1080-Wp PV setup. The system
is also modeled and simulated numerically using the measured
characteristics of each individual component. In each case, the
system performance is analyzed and the energy utilization efficiency is calculated for different weather conditions.
II. EXPERIMENTAL SETUP AND METHODOLOGY
An experimental PV pumping system prototype comprised
of a 1080-Wp PV array, a step down dc–dc converter, and
a dc motor loaded by a centrifugal pump was constructed.
The PV array (Fig. 2) was installed facing south at a fixed
tilt angle of 54 with respect to the horizontal on the roof of
the Charles Parsons Technology Centre (CPTC) building of
the New and Renewable Energy Centre (NaREC) in Blyth,
Northumberland, U.K. This PV array consists of six 180-Wp
SANYO HIP-J54BE2 solar modules. To suit the motor voltage
rating, this array is divided into two parallel branches of three
series connected modules. A protection diode is connected in
series with each array branch to block any current flow from
the system to the array. On the same roof, a Vaisala MAWS201
weather station is installed where weather parameters are
recorded at a 1-s sampling rate. Solar irradiance was measured
by a global radiation sensor fixed on a surface inclined at
the same tilt angle as that of the solar array. Array surface
temperature was calculated from the available measurements
of the ambient temperature, solar irradiance, and wind speed.
The terminals of the PV generator are connected at a connection control cabinet next to where the pumping system, the
Fig. 3. Experimental PV pumping system setup.
dc–dc power converter, and the measuring probes are located
(Fig. 3).
The – curves of the PV array were measured utilizing two
series connected 120- sliding resistors connected directly to
the array. Array current and voltage were measured using a Tektronix TSD 2014B digital oscilloscope with an A622 current
probe and a P5200 high voltage differential probe. The same instruments are also used for measuring array/motor current and
voltage in the directly connected system. Weather parameters
were monitored and only – curves with no significant irradiance/temperature variations over the measurement interval were
retained. Measurements were taken at different times during the
day to cover different irradiance levels. The effects of the ohmic
losses in the connection cables, the voltage drops across the protection diodes, and the impact of any dissimilarity in module
characteristics were accounted for by measuring – curves of
the PV generator at the load terminals.
A SunPumps SCB 10-185 motor-pump set was utilized. This
set consists of a ten-stage centrifugal surface pump driven by
a PM brushed dc motor. The pump is designed to operate with
best efficiency at a static head of higher than 50 m when operated
at its nominal voltage. It is usually used either for boosting the
water pressure of a fresh water network or with a drip irrigation
network. Since it is difficult to maintain a static head of 50 m
inside the laboratory, the pump was used to circulate the water
in and out of a water tank with a static head of about 1 m. At
this operating point, the pump has a low efficiency. However,
if the pump were to be operated at the same terminal voltage
in a higher static head application, the operating point would
be located at a high efficiency point on the same head-flow rate
curve.
The motor-pump set was first operated from a dc power
supply to measure its parameters before being used with the PV
generator. Motor current and voltage were measured with high
resolution digital multimeters and a digital oscilloscope. Motor
speed was measured with a TENMA 72-6633 handheld digital
phototachometer. Pumping head and flow rate were measured
with a Reliance Water Controls WATM 200-016 MNK Multijet
turbine water flow meter and a TECSIS 1425-075092 pressure
gauge. A discharge valve was used to control the pumping
pressure. The pumping head was varied by controlling the
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IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, VOL. 1, NO. 3, OCTOBER 2010
valve, from 1 m when the valve is fully opened to a maximum
value of 93 m when the valve is fully closed and the motor
operating at its rated voltage of 135 V.
For constant voltage operation, a step-down dc–dc power
converter was constructed and used as an interface between the
PV array and the motor-pump set. The link capacitance and
the PWM frequency of the converter are fixed at 470 F and
10 KHz, respectively. The PV array current and voltage were
measured with Hall Effect sensors: LTS15-NP and LV25-P,
respectively. The current measurements were not used as part
of the control system but were included for data acquisition
purposes only. A Texas Instruments TMS320F2812 DSP-based
eZdsp kit was used for control and data acquisition utilizing
the real-time data exchange (RTDX) feature of the DSP. This
DSP-based control hardware was used for experimental flexibility and ease of programming. In a commercial product, a
lower cost microcontroller would be more than adequate to
implement the control algorithms under investigation.
To analyze the system performance with constant voltage operation under both transient and steady-state conditions, system
parameters were recorded with a resolution of 2 K samples/s. A
test duration of 20 min was chosen to study the effects of solar
irradiance/cell temperature variations on system behavior and
to calculate the energy utilization efficiency at different weather
conditions. In this test, the parameters are recorded with a low
acquisition rate of 10 samples/s to limit the host computer buffer
size and the storage memory required for the acquisition files.
III. SYSTEM MODELING
In order to simulate the system numerically, simple and accurate models are derived for the PV generator and the centrifugal
pump based on their measured characteristics. The parameters
of a simple linear model of the motor [18] were derived from
measurements made on the PM machine. For the sake of simplicity, an ideal lossless model was assumed for the power converter.
A. PV Generator Model
Different models of the solar cell have been used to describe
its electrical behavior. Mathematical models derived from the
one-diode or the two-diode solar cell equivalent circuits are the
most common [16], [17]. These models usually give the cell current as a nonlinear implicit function of the cell voltage requiring
a nonlinear numerical technique such as the Newton–Raphson
method to solve the equation. This iterative process is time consuming especially if high accuracy is required.
For this investigation, a faster look-up table-based model was
developed to simulate the PV generator (Fig. 4). The measured
– curves were scaled to 25 C cell temperature utilizing the
temperature coefficients of the PV module and used to construct
a look-up table. The influence of cell temperature was accounted
for using the temperature coefficients of the array short circuit
current and open circuit voltage. These were also used to calcuand current
from look-up
late the MPP voltage
and
, respectively, at 25 C cell temperatables of
ture. The effect of temperature on the fill factor of the PV array
was neglected. This is a reasonable assumption for the proposed
Fig. 4. Look-up table-based model for PV generator.
Fig. 5. PM brushed dc motor model.
system due to the better temperature characteristics of the Heterojunction with Intrinsic Thin layer (HIT) PV modules used in
the investigation and the cold climate of the installation site.
A simple model was developed to calculate the cell temperfrom the ambient temperature
, the solar irraature
, and the wind speed
, assuming that the cell
diance
acquires thermal energy from the solar radiation thus increasing
. It was also assumed that thermal enits temperature by
ergy is lost by free convection and also by forced convection
when the PV array is exposed to the wind. This energy flow
to the surrounding air decreases the cell temperature by
(free convection) and
(forced convection), as described in
and , be(1). Linear relationships were assumed between
and
, and between
and the product of
tween
and
. The resultant model is illustrated in (2), where
and
are constants chosen to give minimum standard deviation of
the difference between calculated and the measured cell temperatures
(1)
(2)
To compensate for the long time constant of the solar cell,
measured data was averaged every 150 s. About 900 samples of
cell temperature measured at a variety of conditions gave values
and
, at a standard deviation of
of
2.53 C.
B. PM Brushed DC Motor Model
A simple linear model of the PM dc motor was used in this
investigation, as shown in Fig. 5. The load torque here is the mewhich is a nonlinear function
chanical torque of the pump
of the motor speed.
ELGENDY et al.: COMPARISON OF DIRECTLY CONNECTED AND CONSTANT VOLTAGE CONTROLLED PV PUMPING SYSTEMS
187
Fig. 7. Measured pump torque-speed characteristics.
a useful static head replaces the forced friction head resulting
from partially closing the discharge valve
Fig. 6. Measured pump speed-flow rate and speed-power characteristics.
(4)
C. Centrifugal Pump Model
The centrifugal pump is characterized by its head-flow rate
performance curve at the nominal speed. The
curves at different speeds are commonly estimated using the
affinity laws (Similarity laws) of the pump [19]–[21]. These
laws state that the flow rate is directly proportional to the impeller speed, the head is proportional to the square of the speed,
and the hydraulic power is proportional to the cube of the speed.
Affinity laws can predict the performance curves of the pump
with good accuracy at high speeds but they are not very accurate at low speeds and/or with constant head applications.
The measured flow rate versus speed, head versus speed, and
power versus speed characteristics of the SCB 10-185 pump at
1-m static head and different discharge valve settings are shown
in Fig. 6. For very low speeds, the pressure produced by the
pump is less than the static pressure and the rotation just circulates the water within the pump. When the speed reaches a
, the pump starts delivering water and the
threshold value
flow rate varies linearly with the speed, as expressed in (3) obtained by curve fitting. For high speeds, the constant in this
term and the
equation can be neglected with respect to the
relationship agrees with the affinity laws. The values of and
depends on the discharge valve setting and the static head. These
have maximum values when the discharge valve is fully opened
and
at 1-m static head) and decrease with
(
increasing pumping head
(3)
When the discharge valve is fully opened, the friction head
can be neglected compared to the static head resulting in nearly
constant pumping head and a linear relationship between the hydraulic power and the pump speed (Fig. 6). When the discharge
valve is partially closed, the friction head may become much
higher than the static head depending on the speed and a square
head-speed relationship is obtained by curve fitting as illustrated
by (4), where the values of and depend on the valve setting.
For high speeds, the first-order term can be neglected and the
relationship agrees with the affinity laws. In real applications,
Since the hydraulic power is proportional to the head-flow
rate product, it has a linear relationship with the pump speed
when the discharge valve is fully opened and has a cubic relationship with it when the valve is partially opened. This is represented by (5) obtained by curve fitting of the speed-power relationship. The lower order terms can be neglected at high speeds
matching the affinity laws
(5)
Torque-Speed Characteristic of the Centrifugal Pump:
To start the centrifugal pump, a breakaway torque of about
10%–25% of the nominal torque is required to overcome the
static friction of the moving parts involved, such as bearings
and shaft seals [21]. The breakaway torque may be assumed
to decrease linearly with the pump speed to zero when the
speed reaches 10%–20% of its nominal value [20], [22].
However, this assumption does not match the curve fitting
of the measured torque-speed relationship shown in Fig. 7.
Instead, a nonlinear relationship of a summation of two terms
is assumed for the breakaway torque similar to that given in
[23] for a dc motor. The first is an exponentially decaying term
representing the transition from static to kinetic friction and
the second is a constant term representing Coulomb friction. A
square torque-speed relationship can be derived from the power
equation of the affinity laws. Adding the breakaway torque, the
resultant torque-speed relationship will be as illustrated in (6)
showing very good agreement with the measured torque-speed
characteristic
(6)
IV. DIRECTLY CONNECTED PV PUMPING SYSTEMS
The transient characteristics of the directly connected system
were measured at constant solar irradiance and cell temperature
and simulated at the same irradiance and temperature values. As
188
Fig. 8. Simulated array/motor voltage and current waveforms of directly connected PV pumping system.
Fig. 9. Simulated motor speed and flow rate waveforms of directly connected
PV pumping system.
shown in Fig. 8, once the system is started
s , the operating point of the PV array moves abruptly from the open circuit
condition to a point near the short circuit condition where the
ratio between the array voltage and current equals the armature
resistance of the motor. If the solar irradiance is high enough so
that the current at this point can produce a higher torque than
the break-away torque of the motor-pump set, the motor starts
to rotate. This moves the operating point towards the open circuit voltage again to settle at the intersection between the –
curves of the array and the motor. For the considered system, the
steady-state operating point is located to the left-hand side of the
MPP where the change in array/motor current is very small. If
the solar irradiance changes, the operating point moves to the
new intersection point of the – curves of the array and the
motor. As the motor voltage increases, its speed increases. After
reaching a threshold speed, the pump starts to deliver water with
a flow rate proportional to its speed, as shown in Fig. 9.
Unlike the simulated waveforms, the measured array/motor
voltage and current have spikes with magnitude proportional to
the irradiance level (Fig. 10). Consequently, ripples appear in
the motor speed and the flow rate waveforms, as illustrated in
Fig. 11.
The voltage spikes are attributed to the periodic increase in
the effective resistance of the motor as the commutator segments
pass through the brushes. The increase in the effective resistance
of the motor moves the operating point towards the open circuit condition. The frequency spectrum of the measured motor
voltage at a certain motor speed is concentrated in a single tone,
as shown in Fig. 12. As the solar irradiance increases, the motor
IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, VOL. 1, NO. 3, OCTOBER 2010
Fig. 10. Experimental results showing array/motor voltage and current waveforms of directly connected PV pumping system.
Fig. 11. Simulated motor speed and flow rate waveforms of the directly connected system.
Fig. 12. Normalized frequency spectrum of measured array/motor voltage
waveform of directly connected PV pumping system.
voltage and speed increase, which increases, respectively, the
amplitude and the frequency of the peak harmonic. The relationship between the motor speed and the frequency of the peak
harmonic in the measured motor voltage at different irradiance
levels is linear, as shown in Fig. 13. The slope of the line is 18
per revolution, half the number of commutator segments.
Fig. 14 shows the influence of solar irradiance
(0–1200 W/m and cell temperature (0 C–60 C) on the
location of the MPP (shaded area) and the corresponding
operating points of directly connected and constant voltage
controlled PV pumping systems. These are obtained from
measured pump and array performance characteristics. For
the directly connected motor-pump set, the operating points
are a function of the load characteristics and are never in the
ELGENDY et al.: COMPARISON OF DIRECTLY CONNECTED AND CONSTANT VOLTAGE CONTROLLED PV PUMPING SYSTEMS
189
Fig. 13. Relationship between the frequency of the peak harmonic of the array/
motor voltage and the motor speed of the directly connected system.
Fig. 16. Experimental system performance of directly connected PV pumping
systems under slow changing irradiance.
Fig. 14. Influence of solar irradiance and cell temperature on MPP location.
Fig. 17. Experimental system performance of directly connected PV pumping
systems under fast changing irradiance.
V. CONSTANT VOLTAGE CONTROLLED PV PUMPING SYSTEM
Fig. 15. Influence of solar irradiance and cell temperature on the energy utilization efficiency of directly connected PV pumping system.
required maximum power area for the motor-pump set used in
the experimental investigation.
Energy utilization efficiency is a function of temperature and
solar irradiance levels, as shown in Fig. 15. Utilization is reasonably high for high values of temperature and solar irradiance but
falls sharply with lower irradiance values.
Energy utilization efficiency is calculated for the experimental system for a 400-s period at slow changing (Fig. 16) and
at fast changing (Fig. 17) irradiance giving values of around
62% and 51%, respectively. The lower utilization shown in
Fig. 17 is due to the low irradiance intervals where the operating
point is some distance from the MPP and the slow response of
the system to irradiance changes.
A PV pumping system with constant voltage control includes
a dc–dc converter as shown in Fig. 18. The converter duty ratio is
adjusted using a PI controller to keep the array voltage constant
at the reference value, as shown in Fig. 19.
The transient characteristics of the PV pumping system with
constant voltage control are measured at constant solar irradiance and cell temperature. As shown in Fig. 20, when the system
is started, the operating point of the PV array moves from the
open circuit voltage to settle at the reference voltage in less than
0.1 s. The steady-state array voltage has a high frequency ripple
with a peak–peak magnitude of about 2 V.
The motor draws a high starting current from the link capacitor which decreases as the voltage on the capacitor decreases.
The steady-state motor current equals the array current divided
by the duty ratio of the converter. Due to the higher mechanical time constant of the motor-pump set, the motor speed takes
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IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, VOL. 1, NO. 3, OCTOBER 2010
Fig. 18. Circuit diagram of constant voltage controlled PV pumping system.
Fig. 19. Block diagram of constant voltage control.
Fig. 21. Motor current and speed, load torque, and flow rate waveforms of PV
pumping system with constant voltage control.
Fig. 22. Influence of solar irradiance and cell temperature on the energy utilization efficiency of PV system operated at constant voltage.
Fig. 20. Experimental results showing array voltage, current, and power waveforms of constant voltage controlled PV pumping system.
longer to settle. The high frequency ripple is absorbed by the
motor inertia and does not affect the motor speed (Fig. 21). The
flow rate is proportional to the motor speed while the load torque
is a square function of the speed.
For the constant voltage controlled set, the operating point
corresponding to 162-V operation can occasionally lie on the
MPP depending of irradiance and temperature levels (Fig. 14).
The corresponding energy utilization levels shown in Fig. 22 are
significantly better than the previous directly connected case,
especially at low radiation levels.
Energy utilization efficiency is calculated for the experimental system for a 20-min period at slow changing (Fig. 23)
and at fast changing (Fig. 24) irradiance giving values of approximately 91% in both cases. Due to the fast response of the
PI controller compared to the speed of irradiance changes, the
utilization is not affected greatly by irradiance and temperature
transients.
With the system under investigation, the constant voltage
MPPT algorithm gives an energy utilization of only 91%. This
Fig. 23. Experimental performance of PV pumping system when operated at
constant voltage at nearly constant irradiance.
can be improved marginally if the reference voltage is selected
ELGENDY et al.: COMPARISON OF DIRECTLY CONNECTED AND CONSTANT VOLTAGE CONTROLLED PV PUMPING SYSTEMS
191
ACKNOWLEDGMENT
The authors would like to thank the staff at NaREC and in
particular Dr. S. McDonald for the use of their PV arrays and
for their valuable help and support.
REFERENCES
Fig. 24. Experimental performance of PV pumping system when operated at
constant voltage at nearly constant irradiance.
in accordance with local temperature and average irradiance
conditions instead of the STC value of the MPP voltage. For
more significant improvements in energy utilization, more
complex MPPT control algorithms would be required. For low
power applications, this low utilization efficiency is mitigated
by the simplicity of the algorithm and the low cost of its
implementation. However, for applications at higher power
levels, the cost of control is less important and the use of more
sophisticated control would be justified.
VI. CONCLUSION
This paper has presented a comparative performance analysis and an experimental evaluation of directly connected PV
pumping systems with systems using a reference voltage MPPT
algorithm. The effects of the solar irradiance and cell temperature on system behavior and energy utilization were examined
using a 1080-Wp experimental setup.
The directly connected PV pumping system offers a low-cost
implementation but has poor energy utilization depending on
the distance between the load line and the MPP at different
weather conditions. In the experimental system described, energy utilization efficiency values in the region of 63% and 51%
were measured for slow changing and fast changing irradiance,
respectively. In contrast, the constant voltage MPPT-based
scheme offers better energy utilization especially at low cell
temperatures. For this system, experimental tests produced an
energy efficiency figure of 91% for both slow and fast changing
irradiance. Although the constant voltage MPPT performance
can be improved upon by more sophisticated MPPT algorithms,
it does offer a relatively simple approach which can be implemented in low-cost control hardware.
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Mohammed Ali Elgendy was born in Behera, Egypt
in 1974. He received the B.Sc. degree, in 1997, from
Menoufia University, Egypt, and the M.Sc., in 2003,
from Ain Shams University, Egypt, both in electrical
engineering. He is currently working toward the
Ph.D. degree in electrical engineering at Newcastle
University, U.K.
From June 1998 to May 2006, he was a Research
Assistant at the New and Renewable Energy Department, Desert Research Centre, Cairo, Egypt. His research focuses on control of power electronic converters for standalone photovoltaic systems.
Bashar Zahawi (M’96–SM’04) received the B.Sc.
and Ph.D. degrees in electrical and electronic engineering from Newcastle University, Newcastle upon
Tyne, U.K., in 1983 and 1988.
From 1988 to 1993, he was a design engineer
with a U.K. manufacturer of large variable speed
drives and other power conversion equipment. In
1994, he was appointed as a Lecturer in Electrical
Engineering at the University of Manchester, and in
2003, he joined the School of Electrical, Electronic
and Computer Engineering at Newcastle University,
as a Senior Lecturer. His research interests include small scale generation,
power conversion, and the application of nonlinear dynamical methods to
electrical circuits and systems.
Dr. Zahawi is a chartered electrical engineer.
David John Atkinson received the B.Sc. degree
in electrical and electronic engineering from Sunderland Polytechnic, U.K., in 1978, and the Ph.D.
degree from Newcastle University, Newcastle upon
Tyne, U.K., in 1991.
He is currently a Senior Lecturer in the Power
Electronics, Drives and Machines Research Group
at Newcastle University. He joined the university in
1987 after 17 years in industry with NEI Reyrolle
Ltd. and British Gas Corporation. His research
interests are mainly focussed on control of power
electronics systems including electric drives and converters.
Dr. Atkinson is a chartered electrical engineer.