DC drives

From EvTechWiki

A "DC drive" consists of the DC motor and the DC motor controller. It's best to start with the motor and consider what would be required to control the motor.

Most DC motors are in fact internally AC, but have a mechanical inverter in the form of a commutator. Because a commutator can engage and disengage different combinations of windings as it rotates, this is a suprisingly effective way to produce AC for driving a motor. One proposed but not (as far as I know) implimented way of creating a AC drive is to use a rotary converter with a microcontroller-driven main shaft motor to provide all the simplicity of a DC drive while getting the 'clean' regen and torque control of a AC drive. I suspect that such a rotary converter would be reletively cheap.

There are several different types of DC motors:

• Series Motors
• Permanent Magnet motors
• Brushless DC motors (electronically commutated)

Series and permanent magnet motors can use functionally similar controllers. A brushless DC [BLDC] motor uses a controller that is not unlike a synchronous AC device.

Discussion of AC vs DC drives