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US-20260128691-A1 - BRAKE CONTROL METHOD, DEVICE, MODE CONTROL DEVICE AND COMPUTER READABLE MEDIUM

US20260128691A1US 20260128691 A1US20260128691 A1US 20260128691A1US-20260128691-A1

Abstract

The present application discloses a brake control method, a brake control device and a computer readable medium. The control method includes following steps: collecting a voltage value of a voltage-dividing resistor R 12 ; calculating a first bus voltage value according to the voltage value of the voltage-dividing resistor R 12 ; detecting a change of a bus voltage within a first time interval and calculating a voltage change rate; estimating a second bus voltage value within a second time interval according to the voltage change rate, the second bus voltage value being an estimated bus voltage value; determining a magnitude relationship between the estimated bus voltage value and a preset value; in response that the estimated bus voltage value is greater than the preset value, stopping a slow braking; in response that the estimated bus voltage value is less than the preset value, continuing to performing the slow braking.

Inventors

  • Minming Liu
  • Jiawei Chen

Assignees

  • JIANGSU DONGCHENG TOOLS TECHNOLOGY CO., LTD

Dates

Publication Date
20260507
Application Date
20231027
Priority Date
20221031

Claims (20)

  1. 1 . A brake control method, comprising: collecting a voltage value of a voltage-dividing resistor R 12 ; calculating a first bus voltage value according to the voltage value of the voltage-dividing resistor R 12 ; detecting a change of the first bus voltage value within a first time interval and calculating a voltage change rate; estimating a second bus voltage value within a second time interval according to the voltage change rate, the second bus voltage value being an estimated bus voltage value; determining a magnitude relationship between the estimated bus voltage value and a preset value; in response that the estimated bus voltage value is greater than or equal to the preset value, stopping a slow braking; in response that the estimated bus voltage value is less than the preset value, performing the slow braking.
  2. 2 . The brake control method according to claim 1 , wherein: performing the slow braking comprises performing the slow braking according to a modulation signal with a pulse width modulation (PWM) duty cycle of upper three tubes being 0, and with a PWM duty cycle of the lower three tubes, and the PWM duty cycle of the lower three tubes having a PWM initial duty cycle and gradually increasing.
  3. 3 . The braking control method according to claim 2 , wherein the initial duty cycle is 5%-50%, and when performing the slow braking, the duty cycle is less than 100%.
  4. 4 . The brake control method according to claim 1 , wherein a bus voltage value U total is calculated according to a formula of U total =(R 6 +R 12 )÷R 12 ×U ad , wherein U ad is a voltage value of R 12 , and R 6 is another voltage-dividing resistor.
  5. 5 . The brake control method according to claim 1 , wherein the voltage change rate is a slope, which is calculated according to a formula of K=(U total2 −U total1 )÷T, wherein K is the slope, and T is a time interval for the voltage value of R 12 to change from U total1 to U total2 , U total1 and U total2 are voltage values of R 12 .
  6. 6 . The brake control method according to claim 1 , further comprising: in response that the estimated bus voltage value is greater than the preset value, outputting a PWM modulation signal with a PWM duty cycle of upper three tubes being 0 and a PWM duty cycle of lower three tubes being 0.
  7. 7 . (canceled)
  8. 8 . A brake control device, comprising: a voltage collecting circuit configured to collect a voltage value of a voltage-dividing resistor R 12 ; a MCU configured to calculate a first bus voltage value according to the voltage value of the voltage-dividing resistor R 12 ; detect a change of a bus voltage within a first time interval and calculate a voltage change rate; estimate a second bus voltage value; determine a magnitude relationship between the estimated bus voltage value and a preset value, and stop a slow braking in response that the estimated bus voltage value is greater than the preset value, and perform the slow braking in response that the estimated bus voltage value is less than the preset value.
  9. 9 . A mode control device, comprising: a processor; a non-transitory storage medium, storing computer programs, which when executed by the processor, cause the processor to: collect a voltage value of a voltage-dividing resistor R 12 ; calculate a first bus voltage value according to the voltage value of the voltage-dividing resistor R 12 ; detect a change of a bus voltage within a first time interval and calculate a voltage change rate; estimate a second bus voltage value within a second time interval according to the voltage change rate, the second bus voltage value being an estimated bus voltage value; determine a magnitude relationship between the estimated bus voltage value and a preset value; in response that the estimated bus voltage value is greater than the preset value, stop a slow braking; and in response that the estimated bus voltage value is less than the preset value, perform the slow braking.
  10. 10 . (canceled)
  11. 11 . The brake control device according to claim 8 , wherein the MCU performing the slow braking according to a modulation signal with a pulse width modulation (PWM) duty cycle of upper three tubes being 0, and with a PWM duty cycle of the lower three tubes, and the PWM duty cycle of the lower three tubes having a PWM initial duty cycle and gradually increasing.
  12. 12 . The brake control device according to claim 11 , wherein the initial duty cycle is 5%-50%, and when performing the slow braking, the duty cycle is less than 100%.
  13. 13 . The brake control device according to claim 8 , wherein the MCU calculates a bus voltage value U total according to a formula of U total =(R 6 +R 12 )÷R 12 ×U ad , wherein U ad is a voltage value of R 12 , and R 6 is another voltage-dividing resistor.
  14. 14 . The brake control device according to claim 8 , wherein the voltage change rate is a slope, the MCU calculates the voltage change rate according to a formula of K=(U total2 −U total1 )÷T, wherein K is the slope, and T is a time interval for the voltage value of R 12 to change from U total1 to U total2 , U total1 and U total2 are voltage values of R 12 .
  15. 15 . The brake control device according to claim 8 , wherein in response that the estimated bus voltage value is greater than the preset value, the MCU outputs a PWM modulation signal with a PWM duty cycle of upper three tubes being 0 and a PWM duty cycle of lower three tubes being 0.
  16. 16 . The brake control device according to claim 8 , wherein the preset value comprises a withstand voltage value of the bus voltage.
  17. 17 . The mode control device according to claim 9 , wherein the processor performs the slow braking according to a modulation signal with a pulse width modulation (PWM) duty cycle of upper three tubes being 0, and with a PWM duty cycle of the lower three tubes, and the PWM duty cycle of the lower three tubes having a PWM initial duty cycle and gradually increasing.
  18. 18 . The mode control device according to claim 16 , wherein the initial duty cycle is 5%-50%, and when performing the slow braking, the duty cycle is less than 100%.
  19. 19 . The mode control device according to claim 9 , wherein the processor calculates a bus voltage value U total according to a formula of U total =(R 6 +R 12 )÷R 12 ×U ad , wherein U ad is a voltage value of R 12 , and R 6 is another voltage-dividing resistor.
  20. 20 . The mode control device according to claim 9 , wherein the voltage change rate is a slope, the processor calculates the voltage change rate according to a formula of K=(U total2 −U total1 )÷T, wherein K is the slope, and T is a time interval for the voltage value of R 12 to change from U total1 to U total2 , U total1 and U total2 are voltage values of R 12 .

Description

FIELD The present application relates to a field of electrical tools, and more specifically, to a braking control method, a control device and a computer-readable medium. BACKGROUND In handheld power tools such as electric wrenches and electric circular saws, when stopping, if a direct brake method is used, the direct brake method will cause a brushless motor to instantly generate a huge braking torque, resulting in a large reaction force of the tool, making the user feel poor and noisy; if a slow brake method is used, the slow brake method will reduce the reaction force and the noise of the tool, but repeatedly turning switch tubes on and off will cause current backflow and cause excessive voltage, thereby damaging MOS tubes and affecting a service life of the power tool. Please refer to a Chinese utility model patent issued No. CN213342062U published on Jun. 1, 2021, which discloses that when a switch is disconnected, at least two upper switch tubes or at least two lower switch tubes of an inverter circuit are controlled to be turned on at a first duty cycle less than 100% for braking. When the voltage detected by a peak voltage detection module is higher than a preset value stored in a control module, the control module controls at least two upper switch tubes or at least two lower switch tubes to be turned on at a second duty cycle of 100% for braking. Although it controls a peak voltage generated by an early braking, it does not control a forced power generated by a later braking, which will still generate a lot of noise and make the user feel poor. Therefore, it is necessary to design a brushless direct current (DC) motor braking device and method to solve the above problems. SUMMARY In view of deficiencies in the prior art, a purpose of the present application is to provide a brushless DC motor braking device and method to solve the problems of voltage increase during braking, which may cause damage to electronic components, and to avoid the problems of excessive braking torque, unstable braking transition, and poor user experiment. The present application solves existing technical problems by adopting following technical solutions: a brake control method, comprising: S1: collecting a voltage value of a voltage-dividing resistor R12;S2: calculating a first bus voltage value according to the voltage value of the voltage-dividing resistor R12;S3: detecting a change of a bus voltage within a first time interval and calculating a voltage change rate;S4: estimating a second bus voltage value within a second time interval according to the voltage change rate, the second bus voltage value being an estimated bus voltage value;S5: determining a magnitude relationship between the estimated bus voltage value and a preset value; in response that the estimated bus voltage value is greater than the preset value, stopping a slow braking; in response that the estimated bus voltage value is less than the preset value, performing the slow braking. A further improved solution includes: performing the slow braking comprises performing the slow braking according to a modulation signal with a pulse width modulation (PWM) duty cycle of upper three tubes being 0, and with a PWM duty cycle of lower three tubes, and the PWM duty cycle of lower three tubes having a PWM initial duty cycle and gradually increasing. In a further improved solution, the initial duty cycle is 5 %-50%, and when performing the slow braking, the duty cycle is less than 100%. In a further improved solution, the bus voltage value Utotal is calculated according to a formula of Utotal=(R6+R12)÷R12×Uad, Uad is the voltage value of R12, and R6 is another voltage-dividing resistor. In a further improved solution, the voltage change rate is a slope, which is calculated according to a formula of K=(Utotal2−Utotal1)÷T, K is the slope, and T is a time interval for the voltage value of R12 to change from Utotal1 to Utotal2, Utotal1 and Utotal2 are voltage values of R12. A further improved solution includes: in response that the estimated bus voltage value is greater than the preset value, outputting a PWM modulation signal with a PWM duty cycle of upper three tubes is 0 and a PWM duty cycle of lower three tubes is 0. A further improved solution includes a brake control device, and the brake control device includes: a voltage collecting module, configured to collect a voltage value of a voltage-dividing resistor R12;a first calculation module, configured to calculate a first bus voltage value according to the voltage value of the voltage-dividing resistor R12;a detecting module, configured to detect a change of a bus voltage within a first time interval and calculate a voltage change rate;a second calculation module, configured to estimate a second bus voltage value within a second time interval according to the voltage change rate, the second bus voltage value being an estimated bus voltage value;a determining module, configured to determine a magnitude relationsh