US Patent 7643733
A delta type inverter is used in conjunction With a closed-loop motor controller to provide a control device for driving a three phase brushless direct current motor. The delta inverter has one-half of the solid state switching devices and diodes required by conventional bridge type inventers, thereby improved reliability, and enabling the motor control device to have reduced size, cost and weight. The closed-loop motor controller may include a torque loop for reducing torque ripple during operation of the motor.
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