# US 11,305,810 B2 · Method and system to synchronize non-deterministic events

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- Number: US 11,305,810 B2
- Document ID: US11305810B2
- Status: Granted
- Kind: B2
- Application number: 16/857,610
- Filed: 2020-04-24
- Published: 2021-10-28
- Granted: 2022-04-19
- Earliest claimed: 2020-04-24
- Assignees: Steering Solutions IP Holding Corporation
- Applicants: Steering Solutions IP Holding Corporation
- Inventors: Keyur Patel; Sreekanth Siddam
- Web page: https://patentgrep.com/patent/US11305810B2

## CPC

- B62D 5/046: {Controlling the motor}
- B62D 5/0463: {calculating assisting torque from the motor based on driver input}
- G05B 15/02: electric
- H02P 6/28: Arrangements for controlling current (H02P6/10 takes precedence)
- H02P 21/22: Current control, e.g. using a current control loop
- H02P 27/06: using DC to AC converters or inverters (H02P27/05 takes precedence)
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

Technical solutions for controlling operation of an electric machine by a control system are provided. The control system comprises an inverter and a controller performing a first operation to produce a first output data representing a motor control current command in a first time period beginning at one of a plurality of initial times occurring at a first periodic timing interval. The controller also performs a second operation upon the first output data to produce a second output data in a second time period. The controller also performs a third operation at a periodic command time to produce a motor control voltage command using the second output data in response to satisfaction of a timing criterion. The timing criterion is based upon comparing the command time and occurrence of a posting time after the initial time. A method of enforcing timing restriction to synchronize non-deterministic motor control events is also provided.

## Claims

### Claim 1

A control system for controlling operation of an electric machine, comprising:
an inverter operable to rectify current from alternating current phase buses of the electric machine to a direct current bus with switches; and
a controller operable to:
perform a first operation to produce a first output data representing a motor control current command in a first time period beginning at an initial time, wherein the initial time is one of a plurality of initial times occurring at a first periodic timing interval;
perform a second operation upon the first output data to produce a second output data in a second time period;
wherein at least one of the first time period or the second time period is a non-deterministic time period;
perform a third operation produce a motor control command at one of a plurality of command times occurring at a second periodic timing interval; and
wherein the third operation uses the second output data in response to satisfaction of a timing criterion, the timing criterion based upon comparing the one of the plurality of command times and occurrence of a posting time after the initial time.

### Claim 2 (depends on 1)

The control system of claim 1, wherein satisfaction of the timing criterion comprises the one of the plurality of command times happening after occurrence of the posting time after the initial time.

### Claim 3 (depends on 1)

The control system of claim 1, wherein satisfaction of the timing criterion comprises the one of the plurality of command times happening within a predetermined calibration time of occurrence of the posting time after the initial time.

### Claim 4 (depends on 1)

The control system of claim 1, wherein the motor control command produced by the third operation is a motor voltage command.

### Claim 5 (depends on 1)

The control system of claim 1, wherein performing the third operation upon the second output data in response to satisfaction of the timing criterion further comprises performing the third operation upon a previous data input in response to non-satisfaction of the timing criterion.

### Claim 6 (depends on 1)

The control system of claim 1, wherein the second periodic timing interval is a shorter time than the first periodic timing interval.

### Claim 7 (depends on 1)

The control system of claim 1, wherein the controller is configured to determine the posting time by performing the steps of:
determining an actual length of the first time period to produce the first output data;
determining an actual length of the second time period to produce the second output data;
calculating an actual interval length as the actual length of the first time period plus the actual length of the second time period;
revising the posting time based upon the actual interval length.

### Claim 8 (depends on 1)

The control system of claim 1, wherein the electric machine is configured to perform at least one of: applying an assist torque to a steering system of a vehicle, or controlling the steering system.

### Claim 9

A method of enforcing timing restriction to synchronize non-deterministic motor control events, the method comprising:
performing a first operation to produce a first output data in a first time period beginning at an initial time, wherein the initial time is one of a plurality of initial times occurring at a first periodic timing interval;
performing a second operation upon the first output data to produce a second output data in a second time period;
wherein at least one of the first time period or the second time period is a non-deterministic time period;
determining a posting time based upon a total of the first time period and the second time period; and
enabling a third operation to produce a motor control command at one of a plurality of command times occurring at a second periodic timing interval; and
performing the third operation upon the second output data in response to satisfaction of a timing criterion, the timing criterion based upon comparing the one of the plurality of command times and occurrence of the posting time after the initial time.

### Claim 10 (depends on 9)

The method of claim 9, wherein satisfaction of the timing criterion comprises the one of the plurality of command times happening after occurrence of the posting time after the initial time.

### Claim 11 (depends on 9)

The method of claim 9, wherein satisfaction of the timing criterion comprises the one of the plurality of command times happening within a predetermined calibration time of occurrence of the posting time after the initial time.

### Claim 12 (depends on 11)

The method of claim 11, wherein satisfaction of the timing criterion comprises the one of the plurality of command times happening within the predetermined calibration time before or after occurrence of the posting time after the initial time.

### Claim 13 (depends on 9)

The method of claim 9, wherein performing the third operation upon the second output data in response to satisfaction of the timing criterion further comprises performing the third operation upon a previous data input in response to non-satisfaction of the timing criterion.

### Claim 14 (depends on 9)

The method of claim 9, wherein the first operation comprises generating the first output data representing a motor control current command.

### Claim 15 (depends on 9)

The method of claim 9, wherein the second operation comprises transferring the first output data from a first module configured to perform the first operation to a second module configured to perform the third operation.

### Claim 16 (depends on 9)

The method of claim 9, wherein the third operation comprises generating a motor control voltage command using the second output data.

### Claim 17 (depends on 9)

The method of claim 9, wherein the second periodic timing interval is a shorter time than the first periodic timing interval.

### Claim 18 (depends on 9)

The method of claim 9, wherein the second periodic timing interval occurs an integer number of times within the first periodic timing interval.

### Claim 19 (depends on 9)

The method of claim 9, wherein determining the posting time further comprises:
determining an actual length of the first time period to produce the first output data;
determining an actual length of the second time period to produce the second output data;
calculating an actual interval length as the actual length of the first time period plus the actual length of the second time period;
revising the posting time based upon the actual interval length in response to the actual interval length being longer than the posting time.

### Claim 20 (depends on 9)

The method of claim 9, wherein determining the posting time is performed a fixed number of times after a system initialization event, after which the posting time is unchanged.