4.
0 SIMULATION AND PERFORMANCE ANALYSIS
4.1 COMPONENTS SELECTION AND SPECIFICATIONS
4.1.1 Battery Sizing
Battery Sizing for requirement : (Minimum EV Range 75km per charge, travelling at
60km/h)
At 60 km/h = 4.94kW at wheels
Assume drive line and motor efficiency = 95% & 90%
Target EV range = 75km
Time required = 1.25 hours
Energy Capacity Required= (4.94/(0.9*0.95))*1.25 = 7.22kWh
dSoC Range = 0.6 (assume 0.8SOCmax, 0.2SOC min)
Battery Capacity = (7.22kWh/0.6) =12.03kWh
Max battery power (acceleration) = 97.771kW
I_discharge = 7Q (max rate)
I_max = 600A
Cell (Ah) = 86Ah
Min Battery Voltage Cap = (12.03kWh/86Ah) = 139.88V
Nominal Cell Voltage (Lithium polymer) = 3.7V
No of cells in series = 37pieces 136.9V
Min Battery Voltage (based on max current) = (97.771kW/600) = 162.95V
Nominal Cell Voltage = 3.7V
No of cells in series = 44pieces 162.8V
Actual Capacity = 14kWh
Specific Energy (lithium polymer) = 100Wh/kg
Estimated battery mass = 140kg
Revised EV = (14kWh/(4.94/0.9*0.95))* 60 = 145km
Battery Sizing for requirement (at top speed 120km/h, ESS only)
At 120 km/h = 22.43kW at wheels
Assume drive line and motor efficiency = 95% and 90%
Battery power required = 26.23kW
Pack Voltage = 162.8V
I of ess = 26.23kW/162.8V = 161.12A
Usable capacity = 12.03kWh
Time at top speed = 12.03kWh/ 26.23kW =0.46 hours
EV range at top speed = 0.46 hours * 120km/h =55.2 km
4.1.2 Battery Selection
3.7V and 43Ah per cell, arranged in parallel as to acquire 3.7V, 86Ah.
Total number of cells = 44 x 2 = 88 cells
4.1.3 Engine Generator Sizing
Engine-Generator Sizing(charge at constant speed of 60km/h , at an assumed 2 hours charge)
At 60 km/h = 4.94kW
Assume drive line and motor efficiency = 95% and 90%
Generator power required (Traction) = 5.778 kW
Battery Capacity (20-80%) = 12.03kWh
Battery charging efficiency = 0.9%
Time to charge = Assume 2 hours
Generator Power Required- Charging = 6.68 kW
Total Generator Power Required = 5.778+ 6.68 =12.458kW
Generator Efficiency = 90%
Engine Power Required = 13.84kW
Assume engine rpm = 1500rpm,157.1rad/s
Engine torque required = 88.09Nm
Assume Engine torque at 120% = 105.708Nm
Engine eff = 38%
At top speed of 120km/h, generator only
Wheel power required= 22.43kW
Generator eff = 90%
Engine Power required = 24.92kW
Assume Engine rpm = 2000rpm, 209.47rad/s
Engine Torque Required =118.97Nm
4.1.4 Generator Selection
UQM PowerPhase Pro 100
Or
Drive Motor 1PV5135 4WS14 by SIEMENS
Selection 1 : UQM PowerPhase Pro 100
Type Specifications
Operating Speed 0-7700RPM
Max/Continuous Power 100kW/60kW
Max/Continuous Torque 300Nm/160Nm
Peak Efficiency 95%
Operating Voltage 270-425 VDC
Weight 40kg
Figure 4.1: Efficiency Map of UQM PowerPhase Pro 100
Selection 2: SIEMENS Drive Motor 1PV5135 4WS14
Type Specifications
Operating Speed 0-10000rpm
Max/Continuous Power 120kW/67kW
Max/Continuous Torque 430Nm/160Nm
Peak Efficiency 95%
Operating Voltage 650 VDC
Weight 90kg
Figure 4.2: Efficiency Map of SIEMENS Drive Motor 1PV5135 4WS28
4.2 Vehicle Sub-System Performance – Matlab Simulation
The ICE Generator used is a 1.0 L generator, with fuel tank capacity of 30L. By inserting the
value of battery sizing, generator efficiency mapping of selection 2 and the vehicle
specifications into the series hybrid mode, one can monitor each and every sub-system
performance as details below.
Motor efficiency reached its peak as per figure 4.2 and transverse ups and downs as the speed
varies. Lowest efficiency value has seemed to be around 68%. While the ICE generator hit its
maximum peak efficiency of 38% at then end of each charging.
Figure 4.3: Efficiency graph of Motor and ICE Generator
While the peak velocity and current recorded are 740V and 72A respectively as state of
charge (SOC) goes hike and down over time. Each time the SOC reached 0.2, it will be
recharged by the ICE generator up to 0.80 SOC which then will be re-utilized for driving the
vehicle.
Figure 4.4: State of Charge Graph and Energy Consumption Rate
While the overall energy consumption rate has found to be around 474.7 Wh/km at the end of
the 30L fuel usage. Also, the overall distance covered has found to be 804.3km for the 30L
capacity.
Figure 4.5: Overall Series Hybrid Design for Generator Selection 2
4.3 Comparison of Performance for On-Board Generators
This section sought understanding on how would the difference be in terms of overall
performance when two different types of generators were used. In this case, the generator
mapping efficiency of selection 2 as per tested in section 4.2 is replaced with the efficiency
mapping of generator selection 1, UQM PowerPhase Pro 100. Also note that, generator 1 has
50kg lesser in mass, hence need to be considered into the simulation.
Comparing the efficiency of motor, generator selection 1, UQM PowerPhase Pro 100 reached
its peak efficiency of 95% as per figure 4.6. However the ice generator remain the same.
Figure 4.6: Efficiency graph of Motor and ICE Generator
While the peak velocity and current recorded are 740V and 72A respectively as state of
charge (SOC) goes hike and down over time which appears to be the same result as generator
2. Each time the SOC reached 0.2, it will be recharged by the ICE generator up to 0.80 SOC
which then will be re-utilized for driving the vehicle.
Figure 4.7: State of Charge Graph and Energy Consumption Rate
However, the overall energy consumption rate has found to be around 472.1 Wh/km at the
end of the 30L fuel usage which is higher than generator selection 2. Also, the overall
distance covered has found to be 828.7km for the 30L capacity hence able to reach even
further than previous generator selection.
Figure 4.8: Overall Hybrid Series Model
4.4 Potential Modifications to Improve Energy usage
In order to further improve the energy use, we can opt for a more lighter materials and
components when choosing major equipment. This is because lesser weight will helps to
reduce loads towards the whole system hence improving overall efficiency. By ,
implementing a more aerodynamic friendly chassis which can help reducing aerodynamic
drag coefficient can also helps in improving energy usage of the hybrid model drivetrain.
Also, by running the engine at its best fuel efficiency will also help in boosting energy usage
e.g running the engine at certain RPM and torque that provide its highest efficiency.
