System and method for computing motor speed and rotor position using hall sensor

Patent metadata

Field	Value
Publication number	US-9531310-B2
Application number	US-201414569641-A
Country	US
Kind code	B2
Filing date	Dec 13, 2014
Priority date	Sep 25, 2014
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A method and system for computing a motor speed and a rotor position using a hall sensor are provided. The method improves precision for computing the speed of the motor rotating at a high speed and the rotor position using the hall sensor based on configurations, such as the hall sensor mounted in the motor as a position sensor, a motor controller configured to receive a signal of the hall sensor to operate the motor, and a microcomputer configured to store a time when the motor controller senses the timing of a change in the signal of the hall sensor.

First claim

What is claimed is:

1. A method for computing a motor speed of a motor and a rotor position of the motor using a hall sensor, comprising:
determining, by an inverter controller having installed therein a microcomputer which includes a memory configured to store program instruction and a central processing unit (CPU) configured to execute the program instructions, whether a signal value of the hall sensor is changed;
after determining that the signal value of the hall sensor is changed, computing, by the inverter controller, a time T current at a point which a computation for determining a pulse width modulation (PWM) switching duty starts and a time T Hall at a point at which the signal value of the hall sensor is changed by reading an internal clock counter value according to a CPU clock counter of the CPU of the inverter controller;
computing, by the inverter controller, a motor speed ω r based on a time difference between T Hall which is closest to a current time and a time T Hall _ old which represents the old T Hall value; and
computing, by the inverter controller, a rotor position based on a time difference ΔT between the T Current and the T Hall ;
wherein the hall sensor is mounted within the motor as a position sensor, the inverter controller is configured to receive a signal of the hall sensor to operate the motor, and the microcomputer is configured to store a time at which point the inverter controller senses the change in the signal value of the hall sensor.

2. The method of claim 1 , wherein the time computation for determining the start of the PWM switching duty is performed when the computation for determining the PWM switching duty starts between the timing when the signal value of the hall sensor is changed and the timing when a next signal value of the hall sensor is changed.

3. The method of claim 1 , further comprising:
generating, by the controller, an event triggered by a change in the signal of the hall, and the internal clock counter value of the CPU is automatically recorded in a specific memory of the controller as a value for measuring the T Hall at the point at which the signal value of the hall sensor is changed, based on the generated event.

4. The method of claim 1 , wherein the time T current when the computation for determining the PWM switching duty starts is computed based on T Current =CPU Clock Counter×ΔT CPU by reading the internal clock counter value of the CPU,
wherein, a CPU clock counter represents a CPU internal clock counter to determine timing when an operation to determine a PWM switching duty starts, and ΔT CPU represents a time when the CPU clock counter is increased by one.

5. The method of claim 1 , wherein the time T Hall at the point at which the signal value of the hall sensor is changed is computed based on T Hall =T Hall _ count ×ΔT CPU by reading the internal clock counter value of the CPU,
wherein, T Hall _ count represents the internal clock counter value of the CPU which is automatically stored in the specific memory of the controller, as the time information when the signal value of the hall sensor is changed, and the ΔT CPU represents the time when the CPU clock counter is increased by one.

6. The method of claim 1 , wherein the motor speed ω r is computed based on

ω
r

=

1

N
×

T

Hall
⁢
_
⁢
update

at the timing when the computation for determining the PWM switching duty between the timing when the signal value of the hall sensor is changed and the timing when a next signal value of the hall sensor is changed is performed, wherein, T Hall _ update represents the difference between the time T Hall when a signal value of the hall sensor is changed at a previous time which is closest to a current time, the time T Hall _ old which represents the time required for the signal value of the hall sensor to be changed, and N represents the number of poles of the motor.

7. The method of claim 1 , wherein the rotor position of the motor is computed based on

θ
=

θ
Hall

+

180
TT

⁢

ω
r

⁢

⁢
Δ
⁢

⁢
T

at the timing when the computation for determining the PWM switching duty between the timing when the signal value of the hall sensor is changed and the timing when a next signal value of the hall sensor is changed is performed,
wherein, θ Hall represents an electrical position when a position of the hall sensor determined by a position of a motor where the hall sensor is physically mounted is changed, and ΔT represents the time difference between T Current and T Hall .

8. A system for computing a motor speed of a motor and a rotor position of the motor using a hall sensor, comprising:
an inverter controller having installed therein a microcomputer which includes a memory configured to store program instructions and a processor configured to execute the program instructions, which executed cause the processor to:
determine whether a signal value of the hall sensor is changed;
after determining that the signal value of the hall sensor is changed, compute a time T current at a point which a computation for determining a pulse width modulation (PWM) switching duty starts and a time T Hall at a point at which the signal value of the hall sensor is changed by reading an internal clock counter value according to a CPU clock counter of the processor of the inverter controller;
compute a motor speed ω r based on a time difference between T Hall which is closest to a current time and T Hall _ old which represents the old T Hall value; and
compute a rotor position based on a time difference ΔT between the T current and the T Hall ;

wherein the hall sensor is mounted within the motor as a position sensor, the inverter controller is configured to receive a signal of the hall sensor to operate the motor, and the microcomputer is configured to store a time at which point the inverter controller sense the change in the signal value of the hall sensor.

9. The system of claim 8 , wherein the time computation for determining the start of the PWM switching duty is performed when the computation for determining the PWM switching duty starts between the timing when the signal value of the hall sensor is changed and the timing when a next signal value of the hall sensor is changed.

10. The system of claim 8 , wherein the program instructions when executed are further configured to:
generate an event triggered by a change in the signal of the hall, and the internal clock counter value of the CPU is automatically re

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Lee Dong Hun
• Kang Min Su
• Kwon Soon Woo
• Kim Sung Do
• Lee Joon Yong
• Ryu Chang Seok

Classifications

• H02P6/165 Primary

  Electricity · mapped topic

• H02P27/08 Primary

  with pulse width modulation · CPC title

• H02P6/16 Primary

  Circuit arrangements for detecting position · CPC title

• H02P6/17 Primary

  and for generating speed information · CPC title