US 8,013,552 B2 · Systems and methods for controlling a DC motor

Abstract

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.

Claims21

Dependent claims

A DC motor controller, the controller comprising:

a period detector, wherein the period detector is operable to detect a period associated with a DC motor, wherein the DC motor includes a plurality of phases to which current is applied in accordance with a plurality of commutation states, and wherein the plurality of commutation states includes at least a first commutation state and a second commutation state;
an initial commutation state controller, wherein the initial commutation state controller is operable to:
initialize an up/down counter;
induce a first current in the plurality of phases in accordance with the first commutation state;
increment the up/down counter until the first current achieves a threshold in the first commutation state;
induce a second current in the plurality of phases in accordance with the second commutation state;
decrement the up/down counter until the second current achieves the threshold in the second commutation state;
store the sign bit of the up/down counter;
and
determine a desired initial commutation state based at least in part on the sign bit of the up/down count.

7 more elements

A method for controlling a polyphase, brushless DC motor, the method comprising:

providing a DC motor, wherein the DC motor includes a plurality of phases, wherein operating the DC motor includes inducing currents in the plurality of phases in accordance with a plurality of commutation states, and wherein the plurality of commutation states includes at least a first commutation state and a second commutation state;
initializing a count;
inducing a first current to the plurality of phases in accordance with the first commutation state;
incrementing the count until the current achieves a threshold in the first commutation state;
inducing a second current to the plurality of phases in accordance with the second commutation state;
decrementing the count until the second current achieves the threshold in the second commutation state;
storing the sign bit of the count;
and
determining a desired initial commutation state based at least in part on the sign bit of the count.

6 more elements

A DC motor system, the system comprising:

a DC motor, wherein the DC motor includes a plurality of phases, wherein operating the DC motor includes applying a voltage to the plurality of phases in accordance with a plurality of commutation states, and wherein the plurality of commutation states includes at least a first commutation state and a second commutation state;
an initial commutation state controller, wherein the initial commutation state controller includes an up/down counter, and wherein the initial commutation state controller is operable to:
initialize the up/down counter;
apply a voltage to the plurality of phases in accordance with the first commutation state;
increment the up/down counter until a first current corresponding to the voltage achieves a threshold in the first commutation state;
apply the voltage to the plurality of phases in accordance with the second commutation state;
decrement the up/down counter until a second current corresponding to the voltage achieves the threshold in the second commutation state;
store the sign bit of the up/down counter;
and
determine a desired initial commutation state based at least in part on the sign bit of the up/down counter.

7 more elements

Dependencies are inferred from the claim text.

Systems and methods for controlling a DC motor

Life of this patent

Systems and methods for controlling a DC motor

Life of this patent

Abstract

Claims21