Characterization of Advanced Drive System
for Hybrid Electric Vehicles
Wei Xu1, Jianguo Zhu1, Yongchang Zhang1, Yi Wang1, Guangyong Sun2
1. School of Electrical, Mechanical and Mechatronic Systems, University of Technology, Sydney, NSW, Australia
2. State Key Laboratory of Advanced Design and Manufacture for Vehicle Body, Hunan University, Changsha, China.
E-mail: weixuhappy@ieee.org; joe@eng.uts.edu.au
Abstract — The electric drive is a key component in a plug-in
hybrid electric vehicle (PHEV). The ideal tendency is to use the
electric machine over the entire torque/speed range. This paper
presents the characterization of the electrical drive suitable for a
recently proposed PHEV powertrain, and the design optimization
of the electric machine. The newly proposed PHEV powertrain
has only one electric machine functioning as either a motor or
generator at a time, an energy storage unit consisting of battery
and super-capacitor banks for fast charging/discharging during
regenerative braking and fast acceleration/deceleration, and a
transmission line consisting of two power split devices and a
gearbox. The electric machine must be designed for frequent
start/stop, fast acceleration/deceleration, high torque and power
densities, and high efficiency at all speeds. The drive system was
modeled and characterized by using MATLAB/SIMULINK and
PSAT, while the machine design was conducted through
electromagnetic field analysis by using ANSYS. The design
optimization was carried out for four different electric machines,
including a double salient permanent magnet (DSPM) machine, a
hybrid excitation DSPM (HEDSPM) machine, and two fluxswitching permanent magnet (FSPM) machines of two different
pole arrangements. The results show that the 6/7 pole FSPM
machine has the best performance.
the electricity is produced from a clean energy source, such as
wind and solar, the CO2 emission of a PHEV is then even
smaller. Although these advantages are well recognized,
commercial development has been handicapped. This is for
various reasons, mainly due to the lack of optimal electrical
drive systems which can best meet the requirements as the
major driver for PHEVs.
In general, the HEV powertrains can be classified as the
series, parallel, and series-parallel [1-5]. The series powertrain
is the simplest in structure, but perhaps the most expensive as
it requires the full capacity ICE, generator, and motor. The
parallel powertrain couples the ICE and motor in parallel.
Once the electricity runs out, the ICE drives the car directly
and a full capacity ICE is required. The series-parallel system
incorporates the merits of both the series and parallel systems,
i.e., high efficiency and compact volume, and has been applied
widely in HEVs.
Battery
DC/DC
G
Rectifier
I. INTRODUCTION
With the rapid increase in world population and economy,
vehicles driven by internal combustion engines (ICEs) are
depleting fast the oil supply and causing heavy air pollutions
in cities. As reported in [1], transportation in a typical city
accounts for up to 41% of the CO2 emission. Hybrid electric
vehicles (HEVs) jointly powered by ICEs and electric motors
can dramatically improve the fuel efficiency resulting in a
huge reduction of carbon emission. In an HEV, the electric
motor variable speed drive is employed to implement the
regenerative braking to recover the kinetic energy stored
during acceleration and the electronic continuous variable
transmission (e-CVT), which allows the ICE to be operated at
the constant speeds of highest fuel efficiency. The recent
breakthrough in battery technology has enabled the
development of plug-in HEV (PHEV). In a typical PHEV, the
high energy density battery tank is charged from the grid, and
the electric motor is the prime mover whereas the ICE is only
required to provide the extra torque when the vehicle
accelerates fast and climbing a hill and to drive the generator
when the battery state-of-charge is low [2].
According to the American National Renewable Energy
Laboratory [2], if charged by the electricity from coal fired
power plants, the emission of a PHEV is 76-136 g/mile of CO2,
less than half of that by an ICE-driven car (250-300 g/mile). If
Grid
Supercapacitor
DC/DC
Inverter
Inverter/
Rectifier
Charger
Battery
DC/DC
M
M/G
Engine
Power split device
Engine
Gear
Power s plit device
Gear
Wheel
Fig.1. Toyota hybrid system
configuration.
Wheel
Fig.2. Proposed PHEV system
configuration.
Fig.1 shows the typical structure of the series-parallel
system of the Toyota Prius launched in 1997 [3]. The wheels
are driven by the engine and the electric motor M while the
battery is charged through the generator G that is driven by the
ICE using a power split unit. During the regenerative braking,
both M and G can be controlled to charge the energy storage
units. The powertrain is designed to well suit the need of an
HEV in which the ICE acts as the prime mover. However, the
configuration requires two electric machines, which increases
the system cost, and additional power losses.
A novel PHEV powertrain, which uses only one electric
machine, was proposed in 2008 [4]. As illustrated in Fig.2, it
consists of an energy storage unit comprised of batteries and
super-capacitors, a power control unit including the DC link,
DC/DC converters and a back to back inverter/rectifier, an
electric machine, MG, functioning as either a motor or a
generator, and an ICE working mostly during fast acceleration
to provide the extra torque required. The system operation is
governed by a special energy management strategy as
illustrated in Fig.3, where SOC stands for the state of charge
of the energy storage unit, and EM the electric machine. At the
starting, it is assumed that the battery and super-capacitor
banks are fully charged (SOC high) from the grid, and the
capacity of the energy storage is designed such that the car
should be able to cover a reasonable long range, e.g. 150km,
per full charge. In the normal operation mode (high SOC and
moderate load), the EM works alone as the prime mover of the
car. When there is a need of extra toque for fast acceleration or
hill climbing, the ICE will provide the assistance. When the
SOC drops, the ICE will recharge the battery while the system
is idle, e.g. waiting at traffic lights, and if the load is high and
SOC very low, e.g. after a long distance drive, the ICE will
work alone to drive the car, same as a conventional car. The
braking is performed jointly by the regenerative braking and
mechanical braking.
Braking
High
Mechanical
braking mode
Moderate
SOC
Low
Regenerative
braking mode
terminal voltage increases linearly with the speed. At the base
speed, both the voltage and current reach the limits (the rated
values). In Region II, a flux weakening scheme is employed to
extend the operating speed range under the condition that the
voltage and current do not exceed the rated values, resulting in
constant power or inversely decreasing torque versus speed
curves. In Region III, the torque and power collapse because
of ineffective field weakening – there is insufficient supply
voltage to drive the system and this region should be avoided.
In relation to the road speed limits in Australia, the base speed
would typically be 50 km/h, and the critical speed 200 km/h.
Cruising
EM only mode
EM only or ICE
recharge mode
ICE recharge
mode
ICE and EM
assist mode
Fig.4. Torque and power versus speed curves.
ICE only
mode
Negative
Moderate
High
Power Demand of Vehicle
Fig.3. The energy management strategy for proposed PHEV.
This paper presents the design optimization of the electric
machine for the proposed PHEV. The machine specifications
are determined from the practical requirement of drive
performance, and confirmed by the numerical simulations by
the powertrain system analysis toolkit (PSAT) for three typical
driving cycles: the urban drive schedule (UDDS), extra-urban
drive cycle (EUDC), and highway fuel economy drive
schedule (HWFET). Section II determines the rated power of
the electric machine according to the required dynamic
performance. After a brief qualitative comparison, section III
presents the design optimization of four electric machines
including a double salient permanent magnet (DSPM)
machine, a hybrid excited DSPM (HEDSPM) machine, and
two flux switching permanent magnet (FSPM) machines of
two different pole arrangements. In section IV, a numerical
comparison of commonly used indices, such as power or
torque density, efficiency, and flux weakening ability, shows
that the 6/7 pole FSPM machine has the best performance.
II. DETERMINATION OF SPECIFICATIONS
As shown in Fig.4, the typical torque and power versus
speed curves of the proposed PHEV have three regions: (I) the
constant torque region (below base speed), (II) the constant
power region (between the base and critical speeds), and (III)
the reduced power region (above critical speed). In Region I,
the maximum torque capability is limited by the thermal or
current rating of the electric drive system while the machine
On the other hand, the resistance experienced by a vehicle
running at speed V (m/s) is mainly due to the rolling resistance
and air drag, as expressed below
(1)
Fr = M v g ( f r cos α + sin α ) + 0.5ρ a C D AV 2
2
where Mv is the vehicle mass (kg), g the gravity (9.81 m/s ),
fr the rolling resistance coefficient, the road gradient, V
the vehicle speed (m/s), a the air mass density (1.205
kg/m3), CD the aerodynamic coefficient, and A the front
area of the vehicle (m2).
The corresponding power required to overcome the
resistance, Pr (W), can be expressed as
(2)
Pr = M v g ( f r cos α + sin α )V + 0.5ρ a CD AV 3
By Newton’s law, to accelerate a vehicle from one speed
to another, the traction force required, Ftr, is
Ftr = M v dV dt + M v g ( f r cosα + sin α ) + 0.5ρ a C D AV 2 (3)
and the corresponding traction power required is
Ptr = M v VdV dt + M v g ( f r cos α + sin α )V + 0.5ρ aCD AV 3 (4)
The time it takes to accelerate a vehicle from one speed to
another can then be calculated as
V2
Mv
ta = ³
dt (5)
V1 P V − M g ( f cos α + sin α ) − 0.5ρ C AV 2
tr
v
r
a D
The rated power of the prime mover should be chosen to
meet the required vehicle performance: (1) at the critical speed,
Vc, the vehicle should still have certain capability for further
acceleration, i.e. Prated > Pr; and (2) the acceleration time to
typical cruise speeds should be acceptable.
Table I list an estimate of the component weights of the
proposed PHEV. It is assumed that the vehicle will carry a
driver and four passengers of 80 kg each. The total weight of
the vehicle is 1,600 kg.
TABLE I
WEIGHT OF THE PROPOSED PHEV (unit: kg)
Mechanical accessory
35
Motor
85
Clutch/Torque converter
25
Motor controller
15
Super-capacitor
30
Gearbox
75
Vehicle body
470
Final drive
20
Battery
150
Wheel axle
100
Power converter-energy storage
30
Electrical accessory
15
Power converter-electrical accessory
30
Engine
120
Payload
400
Total
1600
100
3
90
is 50 km/h. The base and critical motor speeds are 3,000
rpm and 12,000 rpm, respectively.
Based on the above analysis, if we choose the rated power
of the motor as 75 kW, the acceleration time is 4.3 s from
standstill to 50 km/h with an average acceleration of 3.2 m/s2,
and acceleration distance of 29.8 m, and 7.0 s from 50 km/h to
100 km/h with an average acceleration of 1.8 m/s2 and
acceleration distance of 150 m. As a comparison, Toyota Prius
uses a 50 kW interior permanent magnet (IPM) motor, and it
takes 4.8 s to accelerate from 0 to 50 km/h, and 8.2 s from 50
to 100 km/h.
For the parameters specified above, the proposed PHEV
performance was simulated by using PSAT for three typical
drive cycles and very satisfactory results were obtained [4].
2.5
80
III. DESIGN OPTIMIZATION
Resistance power (kW)
2
70
1.5
60
1
50
0.5
40
0
30
0
10
20
30
40
50
Rolling resistance
Total resistance
20
10
0
0
20
40
60
80
100
120
140
160
180
200
Vehicle speed (km/h)
Fig.5. Resistance power versus vehicle speed.
14
(1)
(1)x=10,Ptr=68.7kW
(2)x=8,Ptr=70.1kW
(3)x=6,Ptr=73kW
(4)x=4,Ptr=81.4kW
(5)x=2,Ptr=126.7kW
Thrust on driven wheels (kN)
12
(2)
10
(3)
8
(4)
6
(5)
4
2
0
0
20
40
60
80
100
120
140
160
180
200
Vehicle speed (km/h)
Fig.6. Thrust force versus speed for different gear ratio and traction power.
Fig.5 plots the resistance power to the proposed PHEV
2
with the following parameters: Mv = 1600 kg, A = 2.23 m ,
CD = 0.26 and fr = 0.01. The rolling resistance power is the
black dashed line and the aerodynamic resistance is the
difference between red line (total resistance) and the black
line. From the curves, it can be seen that the rolling
resistance power is the higher resistance loss representing
70% of the total resistance at 50 km/h. At higher speeds,
the aerodynamic resistance increases in proportion to the
cube of the speed. At the critical speed, 200 km/h, the
rolling resistance is 14% of the aerodynamic resistance, and
the total resistance power is 70 kW, i.e. Prated > 70 kW.
Fig.6 depicts the thrust force versus vehicle speed at
different gearbox speed ratio, x, and traction power. As
shown, if we choose x = 5, and Ptr = 75 kW, the base speed
For the proposed PHEV, a desired electric machine should
have high efficiency, high power or torque density, high
controllability, strong flux weakening ability for a wide speed
range (ratio of critical and base speed), mechanical robust
structure for reliable maintenance free operation, and so on.
The electrical machines commonly employed for EV
propulsions are DC machines, induction machines, switched
reluctance machines (SRMs), and permanent magnet (PM)
machines, each with their own specific merits and demerits.
DC machines have excellent controllability and performance,
such as linear torque/speed curve and low torque ripples, but
because of the use of brushes and commutators, the reliability
and power or torque density are low. Induction machines,
especially squirrel cage induction machines, have strong rotor
structures (high reliability), and low manufacturing cost, but
the efficiency and power or torque density are also low. In
addition, the induction machine speed control is complicated
and sensitive to machine parameters. SRMs have very robust
construction and outstanding flux weakening ability, but they
have problems of low power density, large torque ripples, and
large noise because of their salient structures. PM machines
have high power density, high efficiency, high controllability
and fast dynamic response. The major weaknesses are the
delicate rotor structure because of the low mechanical strength
of PMs and narrow speed range due to the difficulty to weaken
the field of PMs.
To overcome the weakness of rotor structure and retain the
merits of the PM machines, several variations of the machine
topology can be obtained by placing the PMs on the stator and
employing a solid salient rotor similar to that of the SRM [6].
Fig.7 depicts the recently proposed topologies in this category,
including the DSPM, HEDSPM, and FSPM machines.
From the structures and the PM flux distributions shown in
Fig.7, features of these machines can be readily summarized in
contrast to the conventional PM machines in the following:
(a) Concentrated winding – The edge connection of stator
winding is shorter than distributed ones, which means less
copper loss with the same amplitude of stator current.
(b) Strong thermal dissipation capability – As the PMs are
inserted in the stator, they can have greater cross sectional area
and are less likely to suffer the demagnetization problem. The
winding current density can reach 7-8 A/mm2 or even larger.
In continuous operation, the stator temperature can be
maintained well below 125oC, which is in the range of Hgrade insulation by water cooling.
(a). DSPM machine with 12/8
(stator/rotor) poles.
(b). HEDSPM machine with 12/8
poles.
(c) The mutual inductances are nonlinear functions of the
rotor position and stator currents, which causes difficulty to
the advanced performance control.
(d) With the PMs inserted in the stator, the fabrication of
the stator iron core is more complicated than that of traditional
PM machines.
Fortunately, special considerations in practical design will
be taken to optimize the performance by enhancing the effects
of merits and mitigating the effects of demerits.
To find the most suitable electric machine(s) for the PHEV
propulsion, an exercise of design optimization was conducted
for four different electric machines, namely DSPM machine
with 12/8 stator /rotor poles, HEDSPM machine with 12/8
stator/rotor poles, FSPM machine with 6/7 stator/rotor poles,
and FSPM machine with 12/10 stator/rotor poles, without
rotor skewing, for optimal torque and efficiency as expressed
by the following objective function:
Max f
(c). FSPM machine with 6/7 poles.
(d). FSPM machine with 12/10 poles.
Fig.7 Flux distribution of four machines with stator PMs.
(c) Strong structure robustness – Similar to SRMs, the
rotor has no PMs or brushes, and therefore is suitable for high
speed operation, e.g. above 20,000 rpm. For a given power
rating, as the rated speed increases, the machine volume can
be reduced.
(d) High power or torque density – Same as the traditional
PM machines, PMs are employed to generate the major air gap
flux in the DSPM, HEDSPM, and FSPM machines, and the
merit of high power or torque density is retained.
(e) Great flux weakening ability – It is one of the most
important indices for PHEV propulsion. In general, the flux
weakening ability (ratio of the maximum and base speeds) of
conventional PM machines does not exceed 3. However, some
recent studies [7-9] show that the flux weakening ability of
DSPM machine may reach 3, HEDSPM machine 4, and FSPM
machine 4, which is closely related to their structures.
(f) Good redundancy capability – The stator mounted PM
machines with concentrated windings possess the feature of
independent electric and magnetic circuits among phases such
that the control of each phase is independent of other phases.
When one phase is out of order due to open-circuit fault, the
current of the other two phases could be controlled to maintain
almost the same MMF before the fault [7]. This fault tolerance
provides a favorable redundancy in extreme embarrassments.
(g) Feasible control schemes – The back-EMF of stator
mounted PM machines could be optimized to be close to sine
waves by skewing the rotor, and the advanced control schemes
for traditional machines, such as the vector control and direct
torque control can be readily applied to achieve excellent
steady and dynamic state performances.
The demerits of the stator mounted PM machines include:
(a)There exist partial saturation phenomena in the stator
and rotor components, such as the stator teeth, and rotor poles.
(b)The back-EMF waves contain harmonics, resulting in
extra copper loss.
= a1
η − ηw
T − Tw
+ a2
Tb − Tw
ηb − η w
(6)
where T is the optimal torque, Tw the worst or minimum
acceptable torque, Tb the best or most desired torque, the
optimal efficiency, w the worst or minimum acceptable
efficiency, b the best or most desired efficiency; a1 and a2 are
the weighting factors. As the optimization variables are
normalized such that the objective function is dimensionless,
the designer’s preference can be implemented through the
choice of a1, a2, Tw, Tb, w, and b. In this paper, these
parameters, as tabulated in Table II, were determined through
the PHEV simulation by PSAT in the stage of specification.
For a fair comparison, the main dimensions, such as the
stator outer diameter, air gap length, the axial length, and the
rotor diameters, and ratings, such as the terminal voltage,
stator winding current density, and the rated speed, of the four
machines are chosen to be the same. Table III lists the main
dimensions of the four machines. The flux linkage and torque
curves of the four machines are illustrated in Figs.8-11,
respectively.
TABLE II
INDEXES OF OBJECTIVE FUNCTION
Items
FSPM (6/7)
FSPM (12/10)
DSPM
HEDSPM
a1
0.6
0.6
0.6
0.6
a2
0.4
0.4
0.4
0.4
Tw (Nm)
230
200
110
100
Tb (Nm)
280
220
190
180
T (Nm)
272
215
153.5
137.6
w
0.85
0.84
0.85
0.84
b
0.97
0.97
0.97
0.96
0.971
0.968
0.962
0.952
IV. PERFORMANCE COMPARISON
Four key indices including the power density, torque
density, flux weakening ability, and efficiency, of the four
electric machines are compared in order to find the most
suitable one for the PHEV propulsion.
TABLE III
MAIN DIMENSIONS OF FOUR MACHINES (length unit: mm)
FSPM
FSPM
Items
DSPM HEDSPM
(6/7)
(12/10)
101.5
101.5
101.5
101.5
Outer radius
Stator York height
23
17.5
23.5
23.5
Number of pole
6
12
12
12
Pole width
46.8
23.4
16
16
Pole height
20.4
20.8
17.5
17.5
Number of turns per
13
9
8
8
pole winding
PM
Width
12
8
12
12
Height
36.3
18.1
40
34
0.5
0.5
0.5
0.5
Air gap length
Rotor Pole width
24
12
17
24
Pole height
24.6
24.2
14
14
York
17.5
17.5
25
25
Number of poles
7
10
8
8
21
21
21
21
Radius of shaft
211
211
211
211
Effective axial length
PhaseB
200
PhaseC
180
0.2
160
140
Torque (Nm)
Flux linkage (Wb)
PhaseA
0.25
0.15
0.1
120
80
60
40
0
20
0
90
180
270
0
360
90
180
270
360
Rotor position (electrical degree)
Rotor position (electrical degree)
(a) Flux distribution.
(b) Torque (average: 153.5 Nm).
Fig.8. DSPM machine with 12/8 poles.
-1400Aturns
1400Aturns
200
0Aturns
180
0.3
160
140
Toruqe (Nm)
Flux linkage (Wb)
0.25
0.2
0.15
0.1
120
100
80
60
40
0.05
20
0
0
0
90
180
270
360
0
90
Rotor position (electrical degree)
180
270
360
Rotor position (electrical degree)
(b) Torque (average: 137.6 Nm).
(a) Flux distribution (Phase A).
Fig.9. HEDSPM machine with 12/8 poles.
PhaseA(Wb)
PhaseB(Wb)
Flux linkage (Wb)
0.05
180
270
360
-0.1
-0.15
-0.2
B. Flux Weakening Ability
According to the definitions of flux weakening ability for
DSPM machine [8] and FSPM machine [9], the flux
weakening abilities of the four machines are calculated as
shown in Table V.
TABLE V
FLUX-WEAKENING ABILITY OF FOUR MACHINES
FSPM
FSPM
DSPM HEDSPM
Machine
(6/7 poles) (12/10)
Flux weakening ability
4.24
5.01
3.01
4.17
As shown, the flux weakening ability of the FSPM
machines is stronger than that of the DSPM and HEDSPM
machines because of the greater d-axis inductances. In the
FSPM machines, the ability of the one with 12/10 poles is
larger than that of the one with 6/7 poles mainly because the
one with more poles has smaller PM linkage. Compared with
the DSPM machine, the HEDSPM machine has better flux
weakening ability by using the DC excitation. This, however,
reduces the efficiency because of the extra copper loss
produced by the DC current.
C. Torque
Torque is one of most important performance indices of
electric machines for PHEV propulsion. In the starting and
acceleration stages, the drive machine with a higher torque
could reach the desired speed in a shorter time. In the four
machines, the torque is closely related to the structure and size
of PMs. By optimizing the dimensions of the stator slot, stator
pole, PM width and length, rotor pole, and number of turns of
stator windings in series, etc., the optimal rated torque is
obtained for the four machines as summarized in Table VI,
where the torque ripples are calculated by the definition in [9].
0.1
90
The power densities of the DSPM and HEDSPM machines
are significantly lower than those of the FSPM machines. This
is mainly because less PM material is used in these machines
in order to achieve acceptable flux weakening ability.
PhaseC(Wb)
0.2
0.15
0
-0.05 0
TABLE IV
POWER DENSITY ESTIMATION OF DRIVE MACHINES (unit: kW/kg)
Toyota
FSPM
FSPM
Prius
DSPM HEDSPM
Machine
(6/7)
(12/10)
(IPM)
Power density
1.69
1.93
1.60
1.07
0.9
100
0.05
0
of Toyota Prius, followed by the FSPM machine with 12/10
poles of 1.60 kW/kg. The main reason for the difference in
power density between the two FSPM machines is that the one
with more poles has higher leakage inductance.
Rotor position(electrical degree)
Torque (Nm)
(b) Torque (average: 272 Nm).
(a) Flux distribution (Phase A).
Fig.10. FSPM machine with 6/7 poles.
260
240
220
200
180
160
140
120
100
80
60
40
20
0
0
90
180
270
360
Rotor position (electrical degree)
(b) Torque (average: 215 Nm).
(a) Flux distribution (Phase A).
Fig.11. FSPM machine with 12/10 poles.
A. Power Density
Table IV tabulates the power densities at the rated speed of
the four machines and the IPM of Toyota Prius [10]. As
shown, the FSPM machine with 6/7 poles has the highest
power density of 1.93 kW/kg, which is a little higher than that
TABLE VI
TORQUE DENSITY OF FOUR MACHINES
FSPM
FSPM
DSPM
Items
(6/7)
(12/10)
Average torque (Nm)
272
215
153.5
Torque ripple (%)
2.52
2.93
11.91
HEDSPM
137.7
17.17
As shown, the FSPM machine with 6/7 poles has the
highest average torque and lowest torque ripple, followed by
the FSPM machine with 12/10 poles. While the DSPM and
HEDSPM machines have small rated torque, and their torque
ripples are much higher than those of the FSPM machines.
D. Efficiency
Table VII tabulates the calculated rated efficiency of the
four machines. In the calculation, it is assumed that the total of
the frictional, windage, and stray losses is up to 1.5 % of the
output power. The core loss is calculated by summing up the
core losses in each finite element, which is obtained by
interpolating the silicon steel core loss curves according to the
flux density in each element and the frequency. As shown in
the table, the FSPM machine with 6/7 poles has the highest
efficiency, while the HEDSPM machine with 12/8 poles has
the lowest efficiency because of the extra copper loss
produced by the DC excitation current.
TABLE VII
EFFICIENCY OF FOUR MACHINES
FSPM
FSPM
DSPM HEDSPM
Machine
(6/7)
(12/10)
Efficiency
97.1
96.77
96.2
95.18
V. CONCLUSIONS
The PHEV technology can significantly improve the
energy efficiency, and greatly reduce the greenhouse gas
emission through regenerative braking, e-CVT to improve ICE
efficiency, and electricity produced from clean energy sources.
Using one electrical machine and super-capacitors, the
proposed PHEV can have lower weight, better regenerative
braking, and dynamic performance.
Through a qualitative comparison, it is identified that the
stator mounted PM machines have much more robust rotor
structure while retaining the merits of high power or torque
density and high efficiency of the conventional PM machines.
Through design optimization and numerical comparison, it
is found that among the four stator mounted PM machines
studied, the FSPM machine of 6/7 poles has the best
performance of high power and torque densities, strong flux
weakening ability, high efficiency, and small torque ripples,
which is satisfactory for propulsion of the proposed PHEV.
REFERENCES
C.C. Chan and K. T. Chau, Modern electric vehicle technology, Oxford
University Press, 2001.
[2] M. Ehsani, Y. Gao, S. E. Gay, and A. Emadi, Modern electric, hybrid
electric, and fuel cell vehicles, CRC Press LLC, 2005.
[3] H. Oba, “Characteristics and analysis of efficiency of various hybrid
systems,” Report of Toyota Motor Corporation, 2004, pp.935-957.
[4] W. Xu, J.G. Zhu, etc., “Drive system analysis of a novel plug-in hybrid
vehicle”, in Proc. IEEE Industrial Electronics Society, 2009, pp.37173722.
[5] M. Ehsani, G. Yimin, etc.,"Hybrid electric vehicles: architecture and
motor drives," in Proc. of the IEEE, vol.95, no.4, pp.719-728, Apr. 2007.
[6] Z.Q. Zhu and D. Howe, "Electrical Machines and Drives for Electric,
Hybrid, and Fuel Cell Vehicles." Proceedings of the IEEE, vol.95, no.4,
pp.746-765, Apr. 2007.
[7] W.X. Zhao, "Analysis of fault-tolerant performance of a doubly salient
permanent-magnet motor drive using transient cosimulation method,"
IEEE Trans. Ind. Electron., vol.55, no.4, Apr. 2008, pp.1739-1748.
[8] X.Y. Zhu, etc., "Design and analysis of a new hybrid excited doubly
salient machine capable of field control," in Proc. Industry Applications
Conference, Oct. 2006, pp. 2382-2389.
[9] W. Hua, “Inductance characteristics of 3-phase flux-switching
permanent magnet machine with doubly-salient structure,” Trasactions
of China Electrotechnical Society, vol.22, no.11, pp. 25-32, Nov. 2007.
[10] M. Olszewski, "Evaluation of the 2007 Toyota Camry hybrid synergy
drive system," Apr. 2009.
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