Permanent magnet motor

A permanent magnet electric motor is a kind of brushless electric electric motor that uses long term magnets instead of winding in the field.

This type of motor can be used in the Chevy Bolt[1], the Chevy Volt, and the Tesla Model 3.[2] Other Tesla versions use traditional induction motors motors.[3] Front motors in all-wheel drive Model 3 Teslas are also induction motors.

Long term magnet motors are better than induction engine or motors with field windings for several high-efficiency applications such as for example electric powered vehicles. Tesla’s Chief Electric motor Designer was quoted talking about these advantages, saying: “It’s well known that permanent magnet devices have the advantage of pre-excitation from the magnets, and for that reason you involve some efficiency benefit for that. Induction machines have ideal flux regulation and for that reason you can enhance your efficiency. Both seem sensible for variable-speed drive single-gear transmission as the drive units of the cars. Therefore, you may already know, our Model 3 includes a long term magnet machine now. It is because for the specification of the overall performance and efficiency, the long term magnet machine better solved our price minimization function, and it had been optimal for the range and performance target. Quantitatively, the difference can be what drives the continuing future of the device, and it’s a trade-off between motor cost, range and battery price that is determining which technology will be used in the future.
The magnetic field for a synchronous machine could be provided by using long term magnets made of neodymium-boron-iron, samarium-cobalt, or ferrite on the rotor. In a few motors, these magnets are installed with adhesive on the surface of the rotor core in a way that the magnetic field is certainly radially directed over the atmosphere gap. In other designs, the magnets are inset into the rotor core surface area or inserted in slots just below the surface. Another kind of permanent-magnet motor provides circumferentially directed magnets placed in radial slots offering magnetic flux to iron poles, which setup a radial field in the atmosphere gap.

The main application for permanent-magnet motors is in variable-speed drives where in fact the stator comes from a variable-frequency, variable-voltage, electronically controlled source. Such drives can handle precise speed and position control. Because of the absence of power losses in the rotor, as compared with induction engine drives, also, they are highly efficient.

Permanent-magnet motors can be designed to operate at synchronous velocity from a way to obtain constant voltage and frequency. The magnets are embedded in the rotor iron, and a damper winding is certainly placed in slots in the rotor surface area to Drive Chain provide starting capability. Such a motor will not, however, have means of managing the stator power aspect.