Electric Vehicle Systems & Powertrains Flashcards
7 cards from real EVT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Electric Vehicle Systems & Powertrains flashcards as text
What is 'torque vectoring' in an EV with multiple motors?
Answer: Independently varying torque output to individual wheels to improve handling
Torque vectoring precisely controls how much torque each motor (or wheel) delivers, improving cornering stability and traction without mechanical differentials.
In an EV high-voltage system, what does 'galvanic isolation' protect against?
Answer: Electric shock to vehicle occupants and technicians by separating HV from low-voltage circuits
Galvanic isolation ensures no direct electrical path exists between the high-voltage traction system and the low-voltage (12V) chassis, protecting occupants and technicians.
What is the purpose of the pre-charge circuit in an EV high-voltage system?
Answer: Slowly charge inverter capacitors before closing the main contactors to prevent inrush current damage
The pre-charge resistor and relay gradually charge large capacitors in the inverter to near-battery voltage before the main contactors close, preventing destructive current spikes.
Which parameter does a variable frequency drive (VFD/inverter) primarily adjust to control motor speed?
Answer: The frequency of the AC output supplied to the motor
An inverter varies the frequency of its AC output to control motor speed, since synchronous and induction motor speeds are directly proportional to supply frequency.
What is back-EMF in an electric motor, and when is it highest?
Answer: A counter-voltage generated by the spinning rotor; highest at maximum motor speed
Back-EMF is a voltage opposing the supply generated by the rotating rotor's magnetic field; it increases proportionally with rotor speed and limits top-end current.
In a series hybrid powertrain, the internal combustion engine (ICE) is mechanically connected to:
Answer: A generator that produces electricity to power the drive motor or charge the battery
In a series hybrid, the ICE drives only a generator; the generator's electrical output propels the vehicle through an electric motor, so the ICE never directly drives the wheels.
What does 'peak power' versus 'continuous power' mean for an EV traction motor?
Answer: Peak power is available briefly for acceleration; continuous power is sustainable indefinitely without overheating
EV motors can deliver peak (burst) power for short periods, typically limited by thermal capacity, while continuous power is the level sustainably maintainable without exceeding temperature limits.