Control system and control method

Patent metadata

Field	Value
Publication number	US-10998846-B2
Application number	US-201816603214-A
Country	US
Kind code	B2
Filing date	May 17, 2018
Priority date	May 24, 2017
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A control method and a control system, by which a motor can be controlled. The control system includes a central processing module and a drive control module. In a period in which a voltage is not applied to any phase coil of the motor, the drive control module collects voltages of the coil to which the voltage is not applied, and converts the voltages of the coil into digital signals. The central processing module reads the digital signals and determines whether the running speed of the motor is consistent with a preset speed depending on whether an average value of the digital signals falls within a preset threshold range, which helps to improve the control precision.

First claim

The invention claimed is:

1. A control system, wherein the control system is configured to control a motor, and comprises a central processing module and a drive control module;
when the motor is running, the drive control module is configured to sample a voltage of a phase coil of the motor, to which no voltage is applied, during a period in which no voltage is applied to any phase coil of the motor, and convert the voltage of the phase coil of the motor, to which no voltage is applied, into a digital signal;
the control system is configured to store the digital signal and update the digital signal in real time during the period in which no voltage is applied to any phase coil of the motor;
the central processing module is configured to read the digital signal, and obtain a present average value by performing a mathematical operation on the present digital signal and either a previous average value or an initial value; and
the central processing module is configured to determine whether the present average value falls between a first threshold and a second threshold, wherein the first threshold and the second threshold are set corresponding to a preset speed, and the central processing module is configured to determine whether a running speed of the motor is consistent with the preset speed according to a determination result and send out a control signal.

2. The control system according to claim 1 , wherein the drive control module comprises a coil sample-and-hold circuit and an ADC circuit, the coil sample-and-hold circuit is configured to sample the voltage of the coil, and the ADC circuit is configured to convert the sampled voltage signal of the coil into the digital signal.

3. The control system according to claim 1 , wherein the drive control module further comprises a logic processing register, the logic processing register comprises a bemf register, and the bemf register is configured to store the digital signal converted by the ADC circuit.

4. The control system according to claim 3 , wherein the logic processing register further comprises a micro-step register, and the micro-step register is configured to store a micro-step value of the motor.

5. The control system according to claim 3 , wherein the logic processing register is configured to provide a clock signal to the coil sample-and-hold circuit, to allow voltage sampling of the coil performed by the coil sample-and-hold circuit occurs during the period in which no voltage is applied to any phase coil of the motor.

6. A control method, wherein the control method is used for controlling a motor and is implemented by a control system, and the control system comprises a central processing module and a drive control module;
when the motor is running, the drive control module is configured to sample a voltage of a phase coil of the motor, to which no voltage is applied, during a period in which no voltage is applied to any phase coil of the motor, and convert the voltage of the phase coil of the motor, to which no voltage is applied, into a digital signal;
the control system is configured to store the digital signal and update the digital signal in real time during the period in which no voltage is applied to any phase coil of the motor;
the central processing module is configured to read the digital signal, obtain a present average value of the digital signal, and perform the control method, and the control method comprises the following steps:
a1, reading a first threshold Bemf min , a second threshold Bemf max and either an initial value Bemfaver 0 or a previous average value;
a2, reading a digital signal Bemf i ;
a3, calculating a present average value Bemfaver i according to an equation Bemfaver i =(aBemfaver i-1 +bBemf i )/(a+b), wherein i represents the number of times the digital signal is read, i=1, 2 . . . , and when i=1, Bemfaver i-1 is the initial value Bemfaver 0 ;
a4, determining whether the present average value Bemfaver i falls between the first threshold Bemf min and the second threshold Bemf max , and if yes, proceeding to Step a2, otherwise proceeding to Step a5; and
a5, determining that a running speed of the motor is inconsistent with a preset speed and sending out a control signal.

7. A control method, wherein the control method is used for controlling a motor and is implemented by a control system, and the control system comprises a central processing module and a drive control module;
when the motor is running, the drive control module is configured to sample a voltage of a phase coil of the motor, to which no voltage is applied, during a period in which no voltage is applied to any phase coil of the motor, and convert the voltage of the phase coil of the motor, to which no voltage is applied, into a digital signal;
the control system is configured to store the digital signal and update the digital signal in real time during the period in which no voltage is applied to any phase coil of the motor;
the central processing module is configured to read the digital signal, obtain a present average value of the digital signal, and perform the control method,
the control method comprises the following steps:
a1, reading a first threshold Bemf min , a second threshold Bemf max and either an initial value Bemfaver 0 or a previous average value;
a2, reading a digital signal Bemf i ;
a3, calculating a present average value Bemfaver i according to an equation Bemfaver i =(Bemfaver i-1 +Bemf i )/2, wherein i represents the number of times the digital signal is read, i=1, 2 . . . , and when i=1, Bemfaver i-1 is the initial value Bemfaver 0 ;
a4, determining whether the present average value Bemfaver i falls between the first threshold Bemf min and the second threshold Bemf max , and if yes, proceeding to Step a2, otherwise proceeding to Step a5; and
a5, determining that a running speed of the motor is inconsistent with a preset speed and sending out a control signal.

8. The control method according to claim 6 , further comprising Step b3 after Step a2:
Step b3, determining whether a moment when the digital signal is read is within the period in which no voltage is not applied to any phase coil of the motor, and if yes, proceeding to Step a2, otherwise proceeding to Step a3.

9. The control method according to claim 8 , further comprising Step b31 after Step b3:
Step b31, determining whether there is one period, in which no voltage is applied to any phase coil of the motor, included between the read digital signal and the previous digital signal, and if yes, proceeding to Step a3, otherwise proceeding to Step a2.

10. The control method according to claim 9 , further comprising Step b2 after or before Step a1:
Step b2, controlling a motor speed to avoid a resonance interval of the motor, wherein a speed corresponding to the motor resonance interval is related to properties of the motor itself.

11. The control method according to claim 7 , further comprising Step b3 after Step a2:
Step b3, determining whether a moment when the digital signal is read is within the period in which no voltage is not applied to any phase coil of the motor, and if yes, proceeding to Step a2, otherwise proceeding to Step a3.

12. The control method according to claim 11 , further comprising Step b31 after Step b3:
Step b31, determining whether there is one period, in which no voltage is applied to any phase coil of the motor, included between the read digital signal and the previous digital signal, and if yes, proceeding to Step a3, otherwise proceeding to Step a2.

13. The control method according to claim 12 , further comprising Step b2 after or before Step a1:
Step b2, c

Assignees

• Hangzhou Sanhua Res Inst Co Ltd

Inventors

• Jiang Xiaojun
• Yang Likun
• Stanke Edwin J
• Xie Jinlan

Classifications

• H02P29/10 Primary

  for preventing overspeed or under speed · CPC title

• H02P23/00 Primary

  Arrangements or methods for the control of AC motors characterised by a control method other than vector control · CPC title

• H02P8/22 Primary

  Control of step size; Intermediate stepping, e.g. microstepping · CPC title

• H02P23/14

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

• H02P8/34 Primary

  Monitoring operation (H02P8/36 takes precedence) · CPC title