Electric Vehicles

BLDC In-runner Motors: Another type of BLDC motors are the In-runner types. They are used in applications where a transmission unit is required. They are normally coupled along with a differential for 3-wheeled or 4-wheeled EVs. These motors look like normal motors with a shaft and the shaft rotates when the motor is powered. An In-runner type Motor of an E-rickshaw coupled with differential is shown below.

Brushed DC motors: The Brushed DC motor also known as DC series motor was the preferable choice for all old Electric cars. These motors provide a lot of torque which could easily give a sporty feel to the EV. The pull/pick-up of the EV would be almost at par with an average conventional car that these motors were used by drag racers during then. But now after 2008, these motors are not much in use any longer the reason is DC motors cannot provide a constant torque under a varying load. Meaning cursing or climbing a hill with the car will be difficult. Also DC motors cannot start without a load that is it cannot self start due to its high initial current which might damage the motor itself. Today these motors are used in Golf carts commonly a picture of the same is shown below

AC Induction Motors: Most Modern day Electric cars like the Tesla uses an AC Induction motor. The Tesla model S for instance uses a 3-phase AC Induction Motor. Well you might have already guessed it because the company itself is named after Tesla who invented the three phase AC Induction motor. The reason why these motors are selected is that they do not have permanent magnets within them and thus low cost. It also has good life since there are no magnets, magnets would lose their tendency in day course. The downside of the motor would be that it is hard to control the speed and torque of the motor and advanced circuitries are required. Below is the image of Tesla Model S front wheel, taken from Wikipedia.

Controller

There is a very good chance that this question already struck you. We know EV runs on battery which are DC powered and we have motors that run on three phase AC. How will both of these work together? This job is taken car by the Controller, from a basic bi-cycle till a Tesla Roadster every EV has its own controller that converts the DC voltage from the Battery to a suitable level for the Motors to run. It also controls the speed of the motor.