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Electric Vehicle Propulsion - Coggle Diagram
Electric Vehicle Propulsion
AC Motor
Single Phase
Asnchronous
Synchronous
Three-Phase
Asynchronous
Squirrel Cage
Uses a induction Motor (asynchronous)
Cage like: Two circular end caps are joined by rotor bars
Wound Rotor
Rotor is made up of windings which terminate at slip rings on teh shaft
used in special applications where a high starting torque is required
Has Slip
Speed of motor (N) < Ns (N = Ns (1-s)
Synchronous
Permanent
Magnet
Permanent Magnet mounted on the ROTOR
Reluctance
Non-Salient
Pole
Salient Pole
Synchromous speed (Ns) = 120 f / p
Frequency: Current supplies frequency (number of the complete cycle in 1 sec)
(p) Number of pole pairs: determined by how many times a phase winding appears.
DC Motor
Series Wound
Separately Excited Shunt Wound
Permanent Magnet / Brushless
Compounded
Shunt Wound
Attractive for certain application
Very high torque at low speeds making the series DC motor attractive for traction and engine starting applications
Rotational speed can easily be controlled by varying the supply voltage
Rotating part (Rotor) called the armature (winding similar to wound rotor) / Stationary (stator) part introduces a magnetic field by either permanent magnets or field windings which act on the armature
Brush DC Motor
Armature (Electromagnet coil)
Stator (This can be permanent magnet or electromagnet)
Brush (Keeps in contact with commutator and allow for current to flow into the armature)
Shaft
Commutator (a rotary electrical switch that periodically reverses the current between the rotor)
Brushless DC motor
Does not have commutator and brush compared to brush DC motor
Inner Rotor Motor
Heat is easily dissipated from electromagnet coil winding as it is positioned outside. Designed to produce high torque.
Outer Rotor Motor
Heat is from elecgromagnet coil winding is trapped within the permanent magnet. Desgined to operate at lower rated current and low cogging torque.
Motor
The Stator (stationary Part)
The Rotor (rotating part)
Basic Operating Principles of Motor
Oncec the electromagnet has rotated 180 degrees, the polarity of the electromagnet can be changed by changing the direction of current flow. This allows the iron rod to spin continuously.
Generic Block Diagram of a PHEV
Stages of the 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 and power
Measures in either in-ibs or N-m
Horsepower = Torque (N.m) x Speed (RPM) / 50.1503
Motor Efficiency
Efficiency = (Mechanical OUTPUT / Electrical INPUT ) x 100%
Motor losses
Core losses
Stator losses
Rotor losses
Friction and windage losses
Stray load losses
