SYSTEMS AND METHODS FOR CONTROLLING A DC MOTOR

Various systems and methods for controlling DC motors are disclosed herein. For example, one method provides for controlling a polyphase, brushless DC motor. The method includes providing a DC motor that has a plurality of phases. Such a DC motor operates by inducing a current in the plurality of phases in accordance with a plurality of commutation states. In the example, six commutation states are discussed, but fewer than or more than six commutation states may exist. The method further includes initializing a count, inducing a current in the plurality of phases in accordance with a first commutation state, and incrementing the count until the current achieves a threshold in the first commutation state. Then, a current is induced in the plurality of phases in accordance with a second commutation state, and the count is decremented until the current achieves the threshold in the second commutation state. The sign bit of the count is stored, and a desired initial commutation state is determined based at least in part on the sign bit of the count.