Pulsed electric machine control

Patent metadata

Field	Value
Publication number	US-2023253911-A1
Application number	US-202318165100-A
Country	US
Kind code	A1
Filing date	Feb 6, 2023
Priority date	Feb 7, 2022
Publication date	Aug 10, 2023
Grant date	—

Abstract

An electric machine controller is described that is arranged to direct a power converter to cause pulsed operation of the electric machine in selected operational ranges to deliver a desired output. The pulsed operation of the electric machine causes the output of the electric machine to alternate between a first torque level, a second torque level, and an intermediate torque level range providing a shaped pulse pattern. The second torque level is lower than the first torque level and the intermediate torque level range is between the first torque level and the second torque level. The first torque level, second torque level, intermediate torque level range, and shaped pulse pattern are selected to provide a third torque level output such that the system has a higher energy conversion efficiency during the pulsed operation of the electric machine than the system would have when operated at a third torque level that would be required to drive the electric machine in a continuous manner to deliver the third torque level output, wherein the intermediate torque level range is a range of less than 5 Nm and wherein the intermediate torque level range is provided for at least 1 millisecond.

First claim

What is claimed is:

1 . An electric machine controller arranged to direct a power converter to cause pulsed operation of an electric machine in selected operational ranges to deliver a desired output, wherein a pulsed operation of the electric machine causes an output of the electric machine to provide a shaped pulse pattern that alternates between a first torque level, a second torque level, and an intermediate torque level range, wherein the second torque level is lower than the first torque level, wherein the intermediate torque level range is between the first torque level and the second torque level, wherein the first torque level, second torque level, and intermediate torque level range and shaped pulse pattern are selected to provide an overall average system output having a higher energy conversion efficiency during the pulsed operation of the electric machine than the electric machine would have when operated at a third torque level that would be required to drive the electric machine in a continuous manner to deliver the same overall average system output, wherein the intermediate torque level range is a range of less than 5 Nm and wherein the intermediate torque level range is provided for at least 1 millisecond.

2 . The electric machine controller, as recited in claim 1 , wherein the second torque level is substantially zero torque.

3 . The electric machine controller, as recited in claim 2 , wherein the electric machine is controlled using a discontinuous pulse width modulation (DPWM) technique during the second torque level.

4 . The electric machine controller, as recited in claim 2 , wherein the intermediate torque level range has an average intermediate torque level that is no more than 25% of the first torque level.

5 . The electric machine controller, as recited in claim 4 , wherein the electric machine is controlled using discontinuous pulse width modulation (DPWM) technique during the second torque level and intermediate torque level range.

6 . The electric machine controller, as recited in claim 1 , wherein the electric machine controller includes a pulse controller that provides a pulse pattern of the electric machine, wherein the pulse pattern provides the shaped pulse pattern comprising the first torque level for a first period of time, the second torque level for a second period of time, and the intermediate torque level range for a third period of time.

7 . The electric machine controller, as recited in claim 6 , wherein the first period of time and the second period of time and the third period of time are equal.

8 . The electric machine controller, as recited in claim 6 , further comprising providing the intermediate torque level range for a fourth period of time, wherein in the shaped pulse pattern, the third period of time is before the first period of time and the fourth period of time is after the first period of time.

9 . The electric machine controller, as recited in claim 6 , wherein in the shaped pulse pattern, the third period of time is before the first period of time and wherein each shaped pulse pattern has only one period of time at the intermediate torque level range.

10 . The electric machine controller, as recited in claim 1 , wherein the electric machine controller includes a pulse controller that provides a pulse pattern of the electric machine, wherein the pulse pattern provides the shaped pulse pattern comprising at least one first torque level step, at least one second torque level step, and at least one intermediate torque level range step.

11 . The electric machine controller, as recited in claim 10 , wherein the pulse controller that provides the pulse pattern that provides a first plurality of cycles of an AC power at a first amplitude to provide the first torque level step and provides a second plurality of cycles of an AC power at a second amplitude to provide the second torque level and provides a third plurality of cycles of an AC power at an intermediate amplitude range to provide the intermediate torque level range.

12 . A system comprising:
an electric machine; a power converter; and the electric machine controller as recited in claim 1 .

13 . The system, as recited in claim 12 , wherein the electric machine is a motor, and the power converter includes an inverter.

14 . The system, as recited in claim 12 , wherein the electric machine is a generator, and the power converter includes a rectifier.

15 . The system, as recited in claim 12 , wherein the electric machine is configured to operate as a motor/generator.

16 . The system, as recited in claim 12 , wherein the electric machine is an induction machine that has at least three phases.

17 . The system, as recited in claim 12 , wherein the electric machine is a synchronous AC electric machine.

18 . The system, as recited in claim 17 , wherein the electric machine is selected from the group consisting of:
a synchronous reluctance machine, a permanent magnet assisted synchronous reluctance machine; a hybrid permanent magnet synchronous reluctance machine; an externally excited AC synchronous machine; and a permanent magnet synchronous machine.

19 . The electric machine controller, as recited in claim 1 , wherein the electric machine controller includes a pulse controller that provides a pulse pattern of the electric machine, wherein the pulse pattern provides the shaped pulse pattern comprising a first torque level step, at least one second torque level step, and an intermediate torque level step, wherein the shaped pulse pattern has only one first torque level step and only one intermediate torque level step.

20 . The electric machine controller, as recited in claim 1 , wherein the electric machine controller includes a pulse controller that provides a pulse pattern of the electric machine, wherein the pulse pattern provides the shaped pulse pattern comprising a first torque level step, at least one second torque level step, and an intermediate torque level step, wherein the shaped pulse pattern has only one first torque level step and has two intermediate torque level steps, wherein the two intermediate torque level steps are a first intermediate torque level step and a second intermediate torque level step.

21 . The electric machine controller, as recited in claim 20 , wherein the first intermediate torque level step lasts a first period of time and the second intermediate torque level step lasts a second period of time, wherein the first period of time equals the second period of time.

22 . The electric machine controller, as recited in claim 20 , wherein the first intermediate torque level step lasts a first period of time and the second intermediate torque level step lasts a second period of time, wherein the first period of time is not equal to the second period of time.

23 . The electric machine controller, as recited in claim 1 , wherein the shaped pulse pattern further comprises a second intermediate torque level range, wherein the second intermediate torque level range is between the first torque level and the second torque level and is different from the intermediate torque level range and wherein the second intermediate torque level range is a range of less than 5 Nm and wherein the second intermediate torque level range is provided for at least 1 millisecond.

24 . The electric machine controller, as recited in claim 23 , wherein the shaped pulse pattern further comprises a thi

Assignees

• Tula Technology Inc

Inventors

• Islam Md Zakirul

Classifications

• H02P23/02 Primary

  specially adapted for optimising the efficiency at low load · CPC title

• H02P21/02

  specially adapted for optimising the efficiency at low load · CPC title

• H02P27/085 Primary

  wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency · CPC title

• H02P23/14

  Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage · CPC title