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Electric Vehicle Propulsion - Coggle Diagram
Electric Vehicle Propulsion
General Motor Principles
Motors
Basic Operating Principles of Motor
AC Motors
AC Motor
The principle of operation for all AC motors relies on the interaction of a revolving magnetic field created in the stator by AC current, with an opposing magnetic field either:
• induced on the rotor (Asynchronous Motor)
• or provided by a separate DC current source (synchronous Motor)
Developing a Rotating Magnetic Field
Synchronous Speed
Types of Rotor
Asynchronous Motor
Squirrel Cage Rotor
Wound Rotor
Synchronous Motor
Permanent Magnet
DC Motor
Brushed DC Motor
• Operate on direct current (DC)
• Attractive for certain application:
Very high torque at low speeds makes the series DC motor attractive for traction and engine starting applications
Rotational speed can easily be controlled by varying the supply voltage
• DC motor consist of:
Rotating part (rotor) called the armature (winding similar to wound rotor)
Stationary part (stator) introduces a magnetic field by either permanent magnets or field windings which act on the armature
Brushless DC motor
• Working principle:
Torque is produced because of the interaction between the magnetic field generated by the stator coils and the permanent magnets. (ex: positive attract to negative)
In order to keep the motor running, the magnetic field produced by the windings should shift position, as the rotor moves to catch up with the stator field.
Motor Control System
Generic Block Diagram of a PHEV
EV High Voltage Circuit
• Shutdown is when capacity starts to discharge:
Active Discharge
• Reducing high voltage to less than 60 V within 4 seconds
• Transistors in the inverter are pulsed which effectively discharges the capacitor through the motor windings.
• Happens during ignition off, accident
Passive Discharge
• Implemented with the aid of various resistors within the power and control electronics between high voltage positive and high-voltage negative.
• Takes about 120 seconds to discharge
Motor Characteristics
Torque-Speed Characteristics of Motors
Motor Torque and Power
Motor Efficiency
Motor Losses
