# US 12,003,202 B2 · Pulsed electric machine control

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- Number: US 12,003,202 B2
- Document ID: US12003202B2
- Status: Granted
- Kind: B2
- Application number: 18/180,358
- Filed: 2023-03-08
- Published: 2023-07-13
- Granted: 2024-06-04
- Earliest claimed: 2018-03-19
- Assignees: Tula eTechnology, Inc.
- Applicants: Tula eTechnology, Inc.
- Inventors: Adya S. Tripathi
- Web page: https://patentgrep.com/patent/US12003202B2

## CPC

- H02P 23/0004: {Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control}
- H02P 27/08: with pulse width modulation
- B60L 15/08: using pulses
- H02P 27/085: {wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency}
- H03M 3/438: {the modulator having a higher order loop filter in the feedforward path}
- H03M 3/456: {the modulator having a first order loop filter in the feedforward path}
- H03M 3/458: {Analogue/digital converters using delta-sigma modulation as an intermediate step}
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)

## Abstract

A variety of methods, controllers and electric machine systems are described that facilitate pulsed control of electric machines (e.g., electric motors and generators) to improve the machine's energy conversion efficiency. Under selected operating conditions, the electric machine is intermittently driven (pulsed). The pulsed operation causes the output of the electric machine to alternate between a first output level and a second output level that is lower than the first output level. The output levels are selected such that at least one of the electric machine and a system that includes the electric machine has a higher energy conversion efficiency during the pulsed operation than the electric machine would have when operated at a third output level that would be required to drive the electric machine in a continuous manner to deliver the desired output. In some embodiments, the second output level is zero torque.

## Claims

### Claim 1

An electric machine system comprising:
an electrically excited synchronous machine (EESM);
a power converter; and
a controller arranged receive an indication of a desired electric machine output and to direct the power converter to cause pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output, wherein a pulsing frequency of the electrically excited synchronous machine is at least 10 Hz.

### Claim 2 (depends on 1)

The electric machine system as recited in claim 1 wherein the controller is further arranged to vary a pulsing frequency of the electrically excited synchronous machine based at least in part on an operating parameter of the electric machine.

### Claim 3 (depends on 1)

The electric machine system as recited in claim 1 wherein the operating parameter is machine speed.

### Claim 4 (depends on 1)

The electric machine system as recited in claim 1 wherein the controller is further arranged to vary a pulsing frequency of the electrically excited synchronous machine based at least in part on the desired torque output.

### Claim 5

An electric machine system comprising:
an electrically excited synchronous machine (EESM);
a power converter; and
a controller arranged receive an indication of a desired electric machine output and to direct the power converter to cause pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output; and
wherein the controller is further arranged to vary a pulsing frequency varies of the electrically excited synchronous machine based at least in part on noise or vibration considerations.

### Claim 6

An electric machine comprising:
an electrically excited synchronous machine (EESM);
a power converter; and
a controller arranged receive an indication of a desired electric machine output and to direct the power converter to cause pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output; and
wherein the controller includes a sigma delta converter configured to determine at least one of a timing of the outputted pulses, a duration of the outputted pulses, a frequency of the outputted pulses and a pulse cycle duration of the outputted pulses, the pulse cycle duration being a period between beginnings of sequential pulses.

### Claim 7 (depends on 1)

The electric machine system as recited in claim 1 wherein the controller is configured to turn off the electrically excited synchronous machine for at least portions of the times between sequential pulses.

### Claim 8 (depends on 7)

The electric machine system as recited in claim 7 wherein the controller is further configured to turn off the power converter for at least portions of the times between sequential pulses.

### Claim 9 (depends on 1)

The electric machine system as recited in claim 1 wherein the controller is configured such that during the pulsed operation of the electrically excited synchronous machine, an output of the electrically excited synchronous machine varies between a first output level and substantially zero torque output.

### Claim 10 (depends on 1)

The electric machine system as recited in claim 1 wherein the controller is further configured to vary the first output level based at least in part on variations in an operating speed of the electrically excited synchronous machine.

### Claim 11 (depends on 9)

The electric machine system as recited in claim 9 wherein the electrically excited synchronous machine includes a stator and a rotor and the rotor spins continuously during the pulsed operation of the electrically excited synchronous machine.

### Claim 12

A wound field synchronous electric machine (WFSM) comprising:
a power converter; and
a controller arranged receive an indication of a desired electric machine output and to direct the power converter to cause pulsed operation of the wound field synchronous electric machine system during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the wound field synchronous electric machine would attain when driven in continuous manner to deliver the desired output, wherein a pulsing frequency of the wound field synchronous electric machine is at least 10 Hz.

### Claim 13

A method of operating an electrically excited synchronous machine (EESM), the method comprising directing pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output, wherein a pulsing frequency of the electrically excited synchronous machine is at least 10 Hz.

### Claim 14 (depends on 13)

The method as recited in claim 13 further comprising varying a pulsing frequency of the electrically excited synchronous electric machine based at least in part on machine speed during the pulsed operation.

### Claim 15

A method of operating an electrically excited synchronous machine (EESM), the method comprising:
directing pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output; and
varying a pulsing frequency of the electrically excited synchronous electric machine based at least in part on noise or vibration considerations.

### Claim 16

A method of operating an electrically excited synchronous machine (EESM), the method comprising:
directing pulsed operation of the electrically excited synchronous electric machine during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the electrically excited synchronous machine would attain when driven in continuous manner to deliver the desired output; and
wherein a sigma delta conversion is utilized to determine at least one of a timing of the outputted pulses, a duration of the outputted pulses, a frequency of the outputted pulses and a pulse cycle duration of the outputted pulses, the pulse cycle duration being a period between beginnings of sequential pulses.

### Claim 17 (depends on 13)

The method as recited in claim 13 wherein the electrically excited synchronous machine is turned off for at least portions of the times between sequential pulses.

### Claim 18 (depends on 17)

The method as recited in claim 17 wherein the power converter is turned off for at least portions of the times between sequential pulses.

### Claim 19 (depends on 13)

The method as recited in claim 13 wherein during the pulsed operation of the electrically excited synchronous machine, an output of the electrically excited synchronous machine varies between a first output level and substantially zero torque output.

### Claim 20 (depends on 13)

The method as recited in claim 13 wherein the first output level varies at least in part based on variations in an operating speed of the electrically excited synchronous machine.

### Claim 21 (depends on 13)

The method as recited in claim 13 wherein the electrically excited synchronous machine includes a stator and a rotor and the rotor spins continuously during the pulsed operation of the electrically excited synchronous machine.

### Claim 22

An externally excited synchronous machine comprising:
a power converter; and
a controller arranged receive an indication of a desired electric machine output and to direct the power converter to cause pulsed operation of the externally excited synchronous machine system during at least some operating conditions to deliver a net average of the desired output at a higher energy conversion efficiency than the externally excited synchonous machine would attain when driven in continuous manner to deliver the desired output, wherein a pulsing frequency of the externally excited synchronous machine is at least 10 Hz.

### Claim 23 (depends on 22)

The externally excited synchronous machine as recited in claim 22 wherein the controller is further arranged to vary a pulsing frequency of the externally excited synchronous machine based at least in part on an operating parameter of the electric machine.

### Claim 24 (depends on 22)

The externally excited synchronous machine as recited in claim 22 wherein the operating parameter is machine speed.

### Claim 25 (depends on 22)

The externally excited synchronous machine as recited in claim 22 wherein the controller is further arranged to vary a pulsing frequency of the externally excited synchronous machine based at least in part on the desired torque output.

### Claim 26 (depends on 22)

The externally excited synchronous machine as recited in claim 22 wherein the controller is further arranged to vary a pulsing frequency varies of the externally excited synchronous machine based at least in part on noise or vibration considerations.

### Claim 27 (depends on 22)

The externally excited synchronous machine as recited in claim 22 wherein the controller includes a sigma delta converter configured to determine at least one of a timing of the outputted pulses, a duration of the outputted pulses, a frequency of the outputted pulses and a pulse cycle duration of the outputted pulses, the pulse cycle duration being a period between beginnings of sequential pulses.

### Claim 28 (depends on 22)

The externally excited synchronous machine as recited in claim 22 wherein the controller is configured to turn off the externally excited synchronous machine for at least portions of the times between sequential pulses.

### Claim 29 (depends on 28)

The externally excited synchronous machine as recited in claim 28 wherein the controller is further configured to turn off the power converter for at least portions of the times between sequential pulses.

### Claim 30 (depends on 22)

The externally excited synchronous machine as recited in claim 22 wherein the controller is configured such that during the pulsed operation of the externally excited synchronous machine, an output of the electrically excited synchronous machine varies between a first output level and substantially zero torque output.

### Claim 31 (depends on 22)

The externally excited synchronous machine as recited in claim 22 wherein the controller is further configured to vary the first output level based at least in part on variations in an operating speed of the externally excited synchronous machine.

### Claim 32 (depends on 30)

The externally excited synchronous machine as recited in claim 30 wherein the externally excited synchronous machine includes a stator and a rotor and the rotor spins continuously during the pulsed operation of the externally excited synchronous machine.