METHOD AND APPARATUS FOR CONTROLLING PULSE-WIDTH MODULATION IN AN ELECTRIC MOTOR
First Claim
1. A method of controlling pulse-width modulation (PWM) for an electric motor, the method comprising:
- applying PWM pulses of a fixed width to a plurality of stator windings of a stator of the electric motor when a rotational speed of the electric motor is below a pre-determined threshold;
applying, to at least one subset of the plurality of stator windings, at least one PWM pulse having a phase advance with respect to the fixed-width PWM pulses when the rotational speed of the electric motor exceeds the pre-determined threshold;
determining that the rotational speed of the electric motor has dropped from being above the pre-determined threshold to being below the pre-determined threshold; and
disabling power to the plurality of stator windings when it is determined that the rotational speed of the electric motor has dropped below the pre-determined threshold.
6 Assignments
0 Petitions
Accused Products
Abstract
In a method of controlling current in a control circuit of an electric motor, pulse-width modulation (PWM) pulses are applied to a stator of the electric motor, via a plurality of transistors of the control circuit, using a first control mode when a rotational speed of a rotor of the electric motor is within a first range. At least one PWM pulse is applied to the stator, via a subset of the plurality of transistors, using a second control mode when the rotational speed of the rotor is within a second range. When it is determined that the rotational speed of the rotor has changed from being within the second range to being within the first range, additional PWM pulses are applied to the stator such that, for each of the plurality of transistors, a current through the transistor does not exceed a maximum current capacity of the transistor.
-
Citations
20 Claims
-
1. A method of controlling pulse-width modulation (PWM) for an electric motor, the method comprising:
-
applying PWM pulses of a fixed width to a plurality of stator windings of a stator of the electric motor when a rotational speed of the electric motor is below a pre-determined threshold; applying, to at least one subset of the plurality of stator windings, at least one PWM pulse having a phase advance with respect to the fixed-width PWM pulses when the rotational speed of the electric motor exceeds the pre-determined threshold; determining that the rotational speed of the electric motor has dropped from being above the pre-determined threshold to being below the pre-determined threshold; and disabling power to the plurality of stator windings when it is determined that the rotational speed of the electric motor has dropped below the pre-determined threshold. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A motor apparatus comprising:
-
stator having a plurality of stator poles; a rotor configured to rotate in response to pulse-width modulation (P pulses applied to the plurality of stator poles; and a control circuit comprising a plurality of electronic switching mechanisms, the control circuit configured to; apply PWM pulses to the plurality of stator poles based on a rotational speed of the rotor, via the plurality of electronic switching mechanisms; determine that the rotational speed of the rotor has dropped below a pre-determined threshold; and in response to determining that the rotational speed has dropped below the pre-determined threshold, apply additional PWM pulses to the plurality of stator poles such that, for each of the plurality of electronic switching mechanisms, a current through the electronic switching mechanism does not exceed a maximum current capacity of the electronic switching mechanism. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
-
-
15. A method of controlling current in a control circuit of an electric motor, the electric motor having a stator and a rotor configured to rotate in response to pulse-width modulation (PWM) pulses applied to the stator, the method comprising:
-
applying PWM pulses to the stator, via a plurality of transistors of the control circuit, using, a first control mode when a rotational speed of the rotor is within a first range; applying at least one PWM pulse to the stator, via a subset of the plurality of transistors, using a second control mode when the rotational speed of the rotor is within a second range; determining the rotational speed of the rotor; and applying, when it is determined that the rotational speed of the rotor has changed from being within the second range to being within the first range, additional PWM pulses to the stator such that, for each of the plurality of transistors, a current through the transistor does not exceed a maximum current capacity of the transistor. - View Dependent Claims (16, 17, 18, 19, 20)
-
Specification