Abstract: A digital motor controller employs a digital signal processor to generate commutation commands that drive and brake a motor. The commutation commands are pulse width modulated. To avoid shoot-through, the digital signal processor automatically adjusts the widths of the pulses according to the amount of current being drawn by the motor. Motor speed is measured by taking the difference between consecutive samples from a position sensor and dividing the difference by the sampling time. The digital signal processor also closes position, speed and current loops. The commands provided by each loop are limited between upper and lower limits. Further, the digital signal processor automatically adjusts the upper and lower limits to compensate for changes in design characteristics due to variations in temperature. The digital motor controller can be used to control different motors having different design characteristics simply by reprogramming the upper and lower limits.

Abstract: An IC controller for a brushless motor includes commutation logic and an inverter on a single chip. The chip can also include an isolated power supply.

Abstract: A solid state controller is mounted directly to a permanent magnet, brushless DC motor. The controller operates the motor at constant torque and variable speed. Speed is determined in accordance with density of the through flow. The motor and controller can be employed to circulate fluid in a circulation loop having variable pressure.