Pulse modulated control with field weakening for improved motor efficiency
AssigneeTula eTechnology, Inc.
InventorsPaul Carvell, Adya S. Tripathi
Life of this patent
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Abstract
Modulated pulse control of electric machines to deliver a desired output in a more energy efficient manner by either (a) operating the electric machine in a continuous mode when a requested torque demand is greater than the peak efficiency torque of the electric machine or (b) in a pulsed modulation mode when the requested torque demand is less than the peak efficiency torque of the electric machine. When operating in the pulsed modulation mode, the inverter may be deactivated to further improve the system efficiency when field weakening is not required to mitigate or eliminate generation of a retarding torque in situations when Back Electromagnetic Force (BEMF) exceeds a supply voltage for the inverter of the machine.
Claims42
A method comprising:
- operating the motor in a pulsed mode if a received torque demand is less than a threshold;
- and
- applying field weakening to the motor if back electromagnetic force (BEMF) of the motor is more than a supply voltage applied to a power inverter used to excite the motor.
A motor assembly configured to:
- operate a motor in a pulse mode wherein the motor:
- (a) generates substantially no torque between on pulses;
- and
- (b) generates sufficient torque during the on pulses to meet a torque demand;
- and
- apply field weakening during the pulsed mode operation of the motor when back electromagnetic force (BEMF) of the motor exceeds a supply voltage provided to an inverter that is used to excite the motor.
The motor assembly 12, further comprising a sigma-delta torque modulation module configured to use sigma delta modulation to generate a modulated waveform for the inverter to control pulsing of the motor during the pulsed mode operation.
A motor assembly configured to operate in multiple modes, including:
- (a) a first pulsed mode with an inverter used to excite the motor is deactivated during periods between pulses when (i) a torque demand is less than a threshold torque and (ii) back electromagnetic force (BEMF) of the motor is less than a supply voltage provided to the inverter;
- and
- (b) a second pulsed mode with the inverter turned activated, but no torque is demanded during periods between pulses when (i) the torque demand is less than a threshold torque and (ii) back electromagnetic force BEMF of the motor is more than the supply voltage provided to the inverter.
A motor assembly configured to:
- apply field weakening during a pulsed mode operation of a motor of the assembly when back electromagnetic force (BEMF) of the motor exceeds a supply voltage provided to an inverter that is used to excite the motor;
- maintain the inverter activated during periods of time between pulses during pulsed operation when field weakening is applied, but the motor generates no torque;
- and
- when field weakening is not applied, maintaining the inverter in a deactivated state during the periods of time between the pulses.
The motor assembly 31, further comprising a sigma-delta torque modulation module configured to use sigma delta modulation to generate a modulated waveform for the inverter to control pulsing of the motor during the pulsed mode operation.
Dependencies are inferred from the claim text.