Reverse current protection control for electric motors

Abstract

A method is provided. A command to correspond to a target speed of a motor is received. A rotational speed of the motor is measured, and a brake-to-off ratio for a braking interval is calculated based at least in part on the rotation speed, the target speed, a braking parameter. An off state for an inverter that is coupled to motor is induced during an off portion of the braking interval, and a brake signal is applied to the inverter during a braking portion of the braking interval.

Description

Reverse current protection control for electric motors technical field The present invention relates generally to motor control, and more particularly to the control of brushless direct current (DC) motors. Background technique Brushless DC motors are employed in a wide variety of applications and, for example, one application for a brushless DC motor is as a spindle motor for a hard disk drive (HDD) or optical disc drive (i.e. a digital versatile disc or DVD player) . For some of these applications, such as DVD players, speed control of the motor can be very important because the motor will change speed frequently. This means that there are transient periods of braking and acceleration. In particular, for braking, the motor should slow down quickly to generally ensure proper functionality is preserved, and an example of a system 100 - 1 employing a braking scheme can be seen in FIG. 1 . In this example, motor 110 is a three-phase brushless DC motor in which each phase...

AI Technical Summary

Problems solved by technology

Using this short braking period effectively slows down the motor 110 to a desired or target speed during the desired deceleration period (i.e., between times T3 and T4), but the speed is not stable

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