Tesla’s electric motor evolution is an interesting journey that has taken them at this point to the permanent magnet synchronous reluctance motor (PMSRM). Their

Tesla’s electric motor evolution is an interesting journey that has taken them at this point to the permanent magnet synchronous reluctance motor (PMSRM). Their history is very interesting. The early Model S was RWD using an induction motor. The AWD Model S then got a smaller induction motor on the front, keeping the larger sibling in the rear. They then ditched the larger rear motor and just used the same smaller motors front and rear. All the while they were also evolving the software to optimize for torque split, acceleration, and range. They released a feature that they called torque sleep in which the rear motor would pulse off leaving just the front motor driving the car during low torque conditions. The AWD was effectively FWD during these moments, squeezing additional range. When the Model 3 was released, it had a completely new motor, the permanent magnet synchronous reluctance motor. Various names and acronyms called it PMSRM, IPM-SynRM, PMa-SynRM, but the main difference was that now Tesla was moving away from the asynchronous induction motor (and no permanent magnet), to the PMSRM. Having permanent magnets now allowed it to have true “one-pedal” driving, where the car can bring itself to a complete stop without using the physical brakes. With the magnetless induction motors, the driver has to induce a brake hold during a stop, then release, which was still better than keeping the foot on the brake, but one-pedal driving was the luxury feature to have if just for the lazy look-ma-no-pedals stop. Wait there’s more. Tesla in its genius still had inventories of the induction motor, so at first they created an AWD configuration that had the extra-large watermelon-sized induction motor in the rear and cantaloupe-sized PMSRM on front. Software was used to optimize for power or range. Stomp on the power pedal and electricity went to the induction motor. Cruise for range and this load was tasked to the PMSRM. There was enough combined torque and power to go around that Tesla could make these modulations hundreds of times a second. They also sold these combinations as the Performance or Plus version. There was also the LR for Long Range, the LR Plus, the Standard Range, Standard Range Plus). You can guess as to which combination of AWD, RWD, induction, or induction + PMSRM each car model had based on the badging. They did this for a few quarters then went all in on purely PMSRM front and rear. Some Tesla old-school purists still scour the used car listings to find the pure induction models. If you haven’t experienced it you have to try how smooth the Tesla motors are when it comes to one-pedal driving. It’s really good compared to other makers. One-pedal driving isn’t unique to Tesla but there’s something different in their recipe. It’s available in the latest Model S, 3, X, Y with PMSRM. Tesla engineers are a brilliant lot and maybe Robert Sansone can join them and continue the arc of motor evolution and who knows maybe go back to motors without a permanent magnet someday.