Electric and Hybrid Drive Systems homework
ansediao
SummaryOfTopics2019.docxECE 4/5630 Electric & Hybrid Drive Systems Prof Ka C Cheok
SUMMARY
Background
Math
Electrical & Electronics
Mechanical motions
Controls
Matlab, Simulink, Simscape
How to access, get help and view tutorials
Matlab m-script and toolboxes
Simulink model and blocksets
Simscape models and physical model libraries
Climate & Energy
Global Warming
How real is this threat?
What are the evidence?
What are the consequences?
Sources of Energy
Solar Energy
The standard solar panel has an input rate of around 1000 Watts per square meter, however on the solar panels available at present you will only gain roughly 15-20% efficiency at best. Therefore if your solar panel was 1 square meter in size, then it would likely only produce around 150-200W in good sunlight.
Solar electricity, solar car
Solar cooker, solar water heater
Alternative Vehicles
Ch1 Alternative Vehicles
· Energy Efficiencies
· Electric Vehicle (EV)
· Hybrid Electric Vehicle (HEV)
· Plugin Hybrid Electric Vehicle (PHEV)
· Hybrid Vehicles. Are they worth it? User testimonial. Video go to 6:30
· Know Your Toyota Mechanical: Hybrid Synergy Drive commercial overview Video 4 mins
Power Split Device
· Planetary gears
· Parallel PSD – Toyota Prius
· Serial PSD – Hyundai Sonata Hybrid
Simple Vehicle Dynamics
Longitudinal motion![]()
Quarter-car model
Variables
Parameters, value, unit and definition
Pre-compute
The Universe & its Mysterious Forces
Factors of 10 & logarithmic scale
Power of math
The Universe
How long has it been around? 15 billion years
How big is it? 1.4x1026 m radius
How small is it? Quarks. 1x10-15 m radius
Light
Speed of light in vacuum = 299 792 458 m/s = 9.8357e+08 ft/s. I.e., 0.98 feet per nanosecond.
Speed of sound in dry air at 20 °C = 343 m/s = 1,122 ft/s. I.e., 1.122 feet per millisecond.
Interacting Forces of the Universe
Strong nuclear forces
Weak nuclear forces
Electromagnetic forces
Gravitational forces
Electromagnetic Force and Electromechanical Force
Maxwell equations
Ampere’s law twisted pair wires
Faraday’s law right hand rule: emf = thumb, conductor velocity = 1st finger , mag field = middle finger
Lorentz’s law right hand rule: mech force = thumb, current = 1st finger , mag field = middle finger
Ohm’s law
Newton’s law
Electrical Circuit Analysis
Laplace transform
Resistance, reactance, impedance
Resistors, inductance, capacitance
Kirchoff voltage law, Kirchoff current law
Thevenin’s equivalence, Norton’s equivalence
Electromagnet brakes
Magnet falling in copper tube
Magnetic brake for rides,
Magnetic disc brake
COMSOL MultiPhysics
DC Motor
Permanent Magnet & Brushed Commutator
Separately Excited DC Motor
Field circuit at steady state
\
Simple Brushless Motor
Outrunner brushless
Three-Phase Stators with Sinusoidal Distributed Winding
Effective Field Current
.
3-phase voltages & currents space vector voltages & currents
AC Permanent Magnet Synchronous Machine (PMSM)
Effective Torque
Variables:
Parameters:
Rotor and Mechanical Load, and External Torque.
-
Back EMF
When the rotor starts to move, it will induce a back emf (because Faraday says so!).
Field Oriented Control (FOC) Brushless DC (BLDC) Motor
( Space Vector Current/Field Inverse Clarke Transform PWM+ Three P hase Inverter Circuit Y-Stator circuit Hardware Software - Hardware Measurements & Inputs )
Clarke transform, Inverse Clarke, Park transform, Inverse Park transform. d-q components.
AC INDUCTION MOTOR
_
_
Block 1B
Block 1A
Block 1C
Block 1D
Block 2A
Block 2B
Block 3A
Block 3B
Block 4
Block 5A
Block 5B
Stator & Rotor Fields
Basic Hardware + Software Integration
( Space Vector Current/Field Inverse Clarke Transform PWM+ Three Phase Inverter Circuit Y-Stator circuit Hardware Software - Hardware Measurements & )
Compute effective stator field current
1 Control of BLDC Motor
Dynamic Analysis
System Parameter Estimation
Control Schemes
Variable Reluctance Motors
Stepper Motors
Servo Motors
Has closed-loop position control or closed-loop speed contol
Power Electronics Converters
Combination of Discrete Components
· Diodes
· Resistors
· Inductors
· Capacitors
· Transistors
· Bipolar junction transistor (BJT)
· Metal-oxide-semiconductor field-effect transistor (MOSFET)
· Insulated gated bipolar transistor (IGBT)
· Silicon controlled rectifier (SCR), Thyristors
DC-DC Converters
· Buck converter E.g. 12 Vdc to 5 Vdc
· Boost converter E.g., 12 Vdc to 100 Vdc
· Buck-boost converter
Switching circuits
· Efficiency of on-off switching
· PWM
Bidirectional Two-Quadrant Chopper
DC Motor Drive
We can drive a DC motor with Semiconductor H-Bridges, using Bipolar Junction Transistors (BJTs), Field Effect Transistors (FETs) or Insulated-Gate Bipolar Transistors (IGBTs).
Forward Reverse Brake
Brake Fuse Test (only if warranted) Fuse Test (only if warranted)
If you turn on the two upper circuits, the motor resists turning, so you effectively have a breaking mechanism. The same is true if you turn on both of the lower circuits. This is because the motor is a generator and when it turns it generates a voltage. If the terminals of the motor are connected (shorted), then the voltage generated counteracts the motors freedom to turn. It is as if you are applying a similar but opposite voltage to the one generated by the motor being turned. Vis-ã-vis, it acts like a brake.
To be nice to your transistors, you should add diodes to catch the back voltage that is generated by the motor's coil when the power is switched on and off. This flyback voltage can be many times higher than the supply voltage! If you don't use diodes, you could burn out your transistors.
Transistors, being a semiconductor device, will have some resistance, which causes them to get hot when conducting much current. This is called not being able to sink or source very much power, i.e.: Not able to provide much current from ground or from plus voltage.
Mosfets are much more efficient, they can provide much more current and not get as hot. They usually have the flyback diodes built in so you don't need the diodes anymore. This helps guard against flyback voltage frying your MCU.
To use Mosfets in an H-Bridge, you need P-Channel Mosfets on top because they can "source" power, and N-Channel Mosfets on the bottom because then can "sink" power. N-Channel Mosfets are much cheaper than P-Channel Mosfets, but N-Channel Mosfets used to source power require about 7 volts more than the supply voltage, to turn on. As a result, some people manage to use N-Channel Mosfets, on top of the H-Bridge, by using cleaver circuits to overcome the breakdown voltage.
It is important that the four quadrants of the H-Bridgecircuits be turned on and off properly. When there is a path between the positive and ground side of the H-Bridge, other than through the motor, a condition exists called "shoot through". This is basically a direct short of the power supply and can cause semiconductors to become ballistic, in circuits with large currents flowing. There are H-bridge chips available that are much easier, and safer, to use than designing your own H-Bridge circuit.
H-Bridge Devices The L293 has 2 H-Bridges, can provide about 1 amp to each and occasional peak loads to 2 amps. Motors typically controlled with this controller are near the size of a 35 mm film plastic canister. The L298 has 2 h-bridges on board, can handle 1amp and peak current draws to about 3amps. You often see motors between the size a of 35 mm film plastic canister and a coke can, driven by this type H-Bridge. The LMD18200 has one h-bridge on board, can handle about 2 or 3 amps and can handle a peak of about 6 amps. This H-Bridge chip can usually handle an average motor about the size of a coke. There are several more commercially designed H-Bridge chips as well.
Simple BLDC Speed Motor Drive
The fan motors in PC’s are simple brushless dc motors. Significantly more efficient and less maintenance.
Principle of operation
1. Electronically switch on a field coil (e.g. coil A shown)
2. Rotor rotates towards coil A
3. Optical sensor shuts of coil (A) and turns on the next field coil (say B)
4. Rotor rotates towards coil B
5. Process repeats for Coil C and so on.
Notes:
6. Speed is controlled by amplitude of current in coil
7. Direction can be reversed by reversing the currents (not represented in this diagram)
A driver module can be built or purchased
Six-Step Operation in BLDC Motor Drive
Which direction will the motor move?
a) Clockwise
b) Counterclockwise
Space Vector Modulation for BLDC Motor Drive
SVM uses a six-step operation with careful timing schedule to implement a voltage/current field in the stator. The SVM concept is straight forward: There are 6 sectors as shown. We have 8 vectors that we can turn on full blast one at a time. We will only turn on two nonzero vectors as needed.
Say you have to generate these desired voltage field vector such as the ones shown here for each 1 ms period.
0 1 ms 2ms
