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新能源STEM世代
Inspiring Young Minds,
striving for a Greener Hong Kong
New Energy STEM Generation
”可載人太陽能車”工作坊(三) 電力驅動技術
22June2019
2
Key dates
Time to start!
1. Pre-registration 13th April 2. Workshops
27th April - 13th July
3. Technical submission 22th June - 27th July
4. Technical webcast 28th August
5. Submission of all documents 22th July – 27th July
6. Scrutineering day 21tst September
8. Event day 30th November
7. Semi-final
28th September
3
1) Power train exploration2) Energy storage and motor system3) E-mobility 4) Typical questions
Contents
4
Power train exploration
Hub motor
Battery pack
Solar panels
3 wheels:Solar Energy
Mechanical EnergyElectrical Energy
5
Power train exploration
Hub motorMPPT
Battery pack
Solar panels
3 wheels:Solar Energy
Mechanical EnergyElectrical Energy
6
Power train exploration
MotorMPPTBattery pack
Solar panels
4 wheels: Solar Energy
Mechanical Energy
Electrical Energy
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Power train exploration
MPPTBattery pack
Solar panels
Solar Energy
Mechanical Energy
Electrical Energy Motor
Motor
Bad example:
8
Power train exploration
MPPTBattery pack
Solar panels
Solar Energy
Mechanical Energy
Electrical Energy
Motor
Motor
Working
Not Working
If one motor is not working:Car crash accidents
9
Power train exploration
Lets go through the electrical system calculation!
10
Energy storage and motor system
Input
Power
Output
Power
Solar cells →Battery pack →motor
Rolling resistance
Wind resistance
Acceleration
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Energy storage and motor system
Power Sources:
1. Solar cell array giving 9 A, 120 V, (standard conditions);
2. 20, series-connected, 6-V, Ag-Zn batteries.
Power System Schematic
12
Energy storage and motor system
Major Batteries developed for EVs
13
Energy storage and motor system
Storing Electric Energy (1):
Storage Methods. All autonomous cars must use propulsive energy stored in the car.Vehicles using chemical storage run on the energy stored in gasoline or otherhydrocarbon fuels.
Solar energy can be stored in several ways: by sensible storage (heating a mass), byphase change storage (melting a substance) by electrochemical storage or capacitivestorage (conversion to electric energy and storage in a battery or capacitor,respectively), or by flywheel inertial storage (converting electric energy to rotationalkinetic energy and storing it in a spinning flywheel).
Note that inertial storage is intrinsic to all vehicles because each stores kinetic energyin its own mass and the rotating masses of its wheels and drive.
14
Energy storage and motor system
Battery connection:
Example:
3.7 Volts x 10 in serial = 37 VBattery is 2600 mAhFor 3 sets in parallel = 2600mAh x 3 = 7.8AhBattery pack capacity(Wh) = 37 x 7.8 = 288.6 Wh
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Energy storage and motor system
4.17. Energy Source / storage
4.17.1. Any energy storage device, must not exceed a nominal voltage of 48 VDC.
4.17.2. The energy storage device, must be installed outside of the driver’scompartment.
Nominal voltage of battery will be referred to battery specification.
According to 4.18.2. The circuit drawing must contain batteries, fuses, circuit breakers, power switchers, solar generator, power trackers, capacitors, motor-controller or chopper, motor(s) and junctioncables.All components (including Battery) in the circuit drawing must be labelled with their detailed electrical specifications.
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Energy storage and motor system
4.17.3. Only one propulsion battery and one accessory battery per vehicle areallowed.
Propulsion battery
provide power to the power train
Li-ion battery pack need a Battery Management System (BMS)
Accessory battery
provide power to all safety devices such as, E-stop relay, Horn, lighting
cannot be used for cooling systems, electric motors
only one unit
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Energy storage and motor system
4.14.4. The energy storage device, including fuel cell, must be equipped withprotective measures to automatically isolate the said device in the event ofovervoltage, overcurrent, short-circuit, thermal overload and other abnormaloperation of the said device without the need for power other than from the saiddevice.
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Energy storage and motor system
19
Energy storage and motor system
Principle of DC machine rotation• Electric Current• Magnetic Field
• Force (Rotation)
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Energy storage and motor system
• Electric controller(ESC) is required to keep the motor running which is sometimes more expensive than the motor.
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Energy storage and motor system
22
Energy storage and motor system
Parameter:1. N (r/min): Revolution(s) Per
Minute2. Pout(W): Power output3. U(V): Motor voltage4. I(A): Motor current5. Pin(W): Power input6. η (%): Motor power
efficiency
Motor characteristic curve:
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Energy storage and motor system
Parameter:1. N (r/min): Revolution(s) Per
Minute2. Pout(W): Power output3. U(V): Motor voltage4. I(A): Motor current5. Pin(W): Power input6. η (%): Motor power
efficiency7. T(N.m.) Torque
𝑃 = 𝑉 𝑥 𝐼 = 𝑇 𝑥 𝑟𝑝𝑚𝑃in= V x I = 358.2 W
Pout= Pin x η= 358.2 x 0.772=276.5 W
Recall Lesson 1:
I = 9.95 A, V= 36V, and η = 77.2 %
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Energy storage and motor system
Why in-wheel motor?
• high torque
• fast response
• gearless operation
• zero transmission loss
25
Energy storage and motor system
Motor control example:
On/Off Forward/
Reverse Speed control Stop Light & horn Meter display
26
新能源STEM世代
Inspiring Young Minds,
striving for a Greener Hong Kong
New Energy STEM Generation 2019
小休
27
E-mobility
• What is your designed external dimension?
• Which type of chassis do you choose?
– Monocoque
– Space frame/ I beam
• Hand-made or purchase
• Delivery date of the key component?
How about your project progress?
28
E-mobility (I)
Flat SurfaceSheet metal?Thin Balsa wood?
29
E-mobility (II)
30
E-mobility (III)
31
E-mobility (IV)
32
E-mobility (V)
33
Typical Questions
1. Any allowance for the limit of external dimension?
Dimension Limits
Max. Height 1300mm
Max. Width 1300mm
Max. Length 3500mm
Track width 50% of Width
Wheelbase >1000mm
Ground clearance >100mm
Max. vehicle weight (without driver)
225 kg
Driver compartment
Height >880mm
Width >700mm
34
Typical Questions
2. Solar Panel limitation:4.15.2. Maximum allowable solar collector with Silicon solar cells is 1.0 𝑚2.
GaAs solar cells, the maximum solar collector array will be reduced to 50 per cent of the maximum solar collector area specified for Silicon solar cells
Examples: A-300 solar cell mono crystalline silicon:Dimension: 0.125m x 0.125 m = 0.015625 m2
Solar cells allowed: 1/ 0.015625 = 64
35
Typical Questions
MPPT converter
Example:
We have 2 set of 50 W 18V,
2 set of 150W 24V.
At least 2 set of MPPT converter need.
The converter can only work under same voltage level.
Most efficient way is series the solar panels/ separate with converter.
36
Typical Questions
4.14.3. All electrical enclosures, junction boxes, etc. containing harnesses orcomponents with nominal operating voltage over 50 VDC or VAC RMS must havehigh voltage warning labels on the enclosure.
37
Typical Questions
IndependentBraking System
2Primary Braking
Parking Braking
Ensure the car can STOPmoving! Even one of them FAIL!
3. Brake:4.11.1. Two independently triggered braking systems commanded by one single command unit, e.g. a foot pedal or lever, must be installed onto the vehicle.
38
Typical Questions
4.11.3. Each braking system must NOT act on only one side of wheels.
Caution: Each system must NOT act only one side of wheels
39
Typical Questions
4. Light fitting
Headlights in white color
Front and rear turn indicators
In amber color
Stoplights in red color
Head light
Front indicatorBrake light
Rear indicator
40
Typical Questions
Bracket Installation
5. Seat belt installation (at least 4-points)
41
Typical Questions
6. Type of steering wheel
(must be in close-loop)
42
Typical Questions
7. Steering rack
43
Typical Questions
8. Wheels dimension
(can choose different sizes of wheels)
4.13.3. The dimension of all wheels must be identical, and
designed for the intended application, loads, and forces.
44
Typical Questions
9. Fire extinguishermust be fitted with a 1kg fire extinguisher within the cockpit and be accessible to thedriver.
Securely mounted to prevent movement while driving/ braking
All drivers must be trained in using
Pressurised at least 8 bar to 13.5 bar
Info:– Capacity
– Type of fire extinguisher
– Weight
– Date: no more than 2 years
45
Review: Bulkheads and Partitions
Driver Compartment (w/ Fire Extinguisher)
Wheel Compartment
Battery Compartment
Wheel Bulkhead
Joule meter Compartment
Bulkhead
46
Review: Dimensions
Total Width
Track Width
650
1300
700
47
Inspiring Young Minds,
striving for a Greener Hong Kong
完
新能源STEM世代
New Energy STEM Generation 2019
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