IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0460865
(2012-05-01)
|
등록번호 |
US-8907596
(2014-12-09)
|
발명자
/ 주소 |
- Harris, III, Troy W.
- Kallara, Jacob
|
출원인 / 주소 |
|
인용정보 |
피인용 횟수 :
0 인용 특허 :
5 |
초록
▼
A first motor controller generates commanded speeds of a first rotor of a first electric motor for a first time interval and a second time interval. A first speed monitor detects observed speeds of the first rotor for the time intervals. A first ratio is determined based on a relationship between re
A first motor controller generates commanded speeds of a first rotor of a first electric motor for a first time interval and a second time interval. A first speed monitor detects observed speeds of the first rotor for the time intervals. A first ratio is determined based on a relationship between respective commanded speeds and corresponding observed speeds for the first time interval and the second time interval. A first data processor increments a persistence counter for the first motor if the first ratio increases or changes during the time intervals. A first motor deceleration is estimated if the persistence counter exceeds a stall limit count. A target rotor speed of a second motor is adjusted based on the estimated first motor rate of change to track the first motor rate of change (or first rotor speed) if the persistence counter exceeds the stall limit count.
대표청구항
▼
1. A method for controlling a first motor and a second motor of a common assembly, the method comprising: generating a plurality of commanded speeds of a first rotor of a first electric motor for a first time interval and a second time interval within a series of time intervals;detecting a plurality
1. A method for controlling a first motor and a second motor of a common assembly, the method comprising: generating a plurality of commanded speeds of a first rotor of a first electric motor for a first time interval and a second time interval within a series of time intervals;detecting a plurality of observed speeds of the first rotor for the first time interval and the second time interval, each one of the observed speeds corresponding to a respective commanded speed;determining a first ratio based on a relationship between respective commanded speeds and corresponding observed speeds for the first time interval and the second time interval;incrementing a persistence counter for the first motor if the first ratio decreases or changes during the series of time intervals;estimating a first motor deceleration or first motor rate of change in first rotor speed of the first motor if the persistence counter exceeds a stall limit count; andadjusting a target rotor speed of a second motor based on the estimated first motor rate of change to track the first motor rate of change or the first rotor speed if the persistence counter exceeds the stall limit count, wherein the adjusting further comprises decreasing the target rotor speed and current of the second motor to be proportional to the first motor deceleration multiplied by an elapsed time, between the first time interval and the second time interval, plus a previous second rotor speed of the second motor. 2. The method according to claim 1 wherein the incrementing the persistence counter for the first motor further comprises incrementing the persistence counter for the first motor if an inversion of the first ratio increases during the series of time intervals. 3. The method according to claim 1 wherein the adjusting further comprises: decreasing the target rotor speed to a fixed rotor speed at a respective motor input current subject to a corresponding current limit, wherein the target rotor speed is proportional to or equal to the observed first motor speed and wherein the motor input current is less than or equal to the current limit. 4. The method according to claim 1 wherein the adjusting further comprises: decreasing the target rotor speed of the second motor in accordance with the following equation: ω=ω0+αt, where α is the constant negative angular acceleration or deceleration of the first motor deceleration, ω is the target angular velocity of the second motor, and ω0 is previous second rotor speed, and t is elapsed time between the first time interval and the second time interval. 5. The method according to claim 1 wherein the target rotor speed of the second motor is modeled as a time integral to address time-varying angular acceleration in accordance with the following equation: ω(t)=ω0+∫0Tα(t)dt, where ω(t) is the target angular velocity of the second motor for a time within time period T, ω0 is an initial second rotor speed at T=0, α(t) is the negative angular acceleration or deceleration that is a function of time, and is equal to the first motor deceleration at a corresponding time. 6. The method according to claim 1 wherein determining a first ratio based on a relationship between respective fractional representations of commanded speeds and corresponding observed speeds further comprises: determining a common denominator for the respective commanded speeds and a numerator difference between the corresponding observed speeds for the first time interval and the second time interval, a first ratio formed by the numerator difference and the common denominator for the first motor. 7. The method according to claim 1 further comprising: detecting a first current draw of the first motor, where the first motor is subject to variable load and wherein the first motor and the second motor comprise components within a common assembly for cutting material;determining whether the first current draw is greater than a maximum allowable current draw;detecting a second current draw of a second motor and an observed speed versus a commanded speed of at least one of the first motor and the second motor if the first current draw is greater than the maximum allowable current draw. 8. The method according to claim 1 further comprising: detecting a first current draw of the first motor, where the first motor is subject to a variable load and wherein the first motor and the second motor comprise components within a common assembly for cutting material;determining whether the first current draw is greater than a maximum allowable current draw;detecting an observed rotor speed of the first rotor of the first motor;detecting a second current draw of a second motor and an observed speed of the second motor versus a commanded speed of the second motor if the first current draw is greater than the maximum allowable current draw and if the first observed rotor speed is less than a commanded rotor speed for a group of time intervals. 9. The method according to claim 1 wherein the persistence counter for the first motor exceeding a stall limit value is indicative of the first motor approaching or being at a stall mode. 10. The method according to claim 6 wherein: determining the common denominator for the respective commanded speeds and a numerator difference between the corresponding observed speeds if a first current draw of the first motor is greater than a maximum allowable current draw, if a second current draw of the second motor is greater than a maximum allowable current draw, and if an observed speed is less than a commanded speed of the first motor for the first time interval and the second time interval. 11. The method according to claim 6 further comprising: generating a plurality of commanded speeds of a second rotor of a second electric motor for a third time interval and a fourth time interval within a series of time intervals;detecting a plurality of observed speeds of the second rotor for the third time interval and the fourth time interval, each one of the observed speeds corresponding to a respective commanded speed;determining a common denominator for the fractional representations of the respective commanded speeds and a secondary numerator difference between the corresponding observed speeds for the third time interval and the fourth time interval, a second ratio formed by the secondary numerator difference and the common denominator for the first motor;incrementing a secondary persistence counter for the second motor if the second ratio increases or changes during the series of time intervals;estimating a second motor deceleration or second motor rate of change in second rotor speed of the second motor if the second ratio exceeds a stall limit count; andadjusting or decelerating a target rotor speed of a first motor based on the estimated second motor rate of change to track or match the observed rotor speed of the second motor. 12. A system for controlling a first motor and a second motor of a common assembly, the system comprising: a first motor;a second motor;a first motor controller for generating a plurality of commanded speeds of a first rotor of the first electric motor for a first time interval and a second time interval within a series of time intervals;a first speed monitor for detecting a plurality of observed speeds of the first rotor for the first time interval and the second time interval, each one of the observed speeds corresponding to a respective commanded speed;a first persistence counter for determining a difference between the respective commanded speeds and the corresponding observed speeds for the first time interval and the second time interval, incrementing the persistence counter for the first motor if the difference increases during the series of time intervals;a first speed control module for estimating a first motor rate of change in first rotor speed of the first motor if the persistence counter exceeds a stall limit count; anda second motor controller for adjusting a target rotor speed of the second motor based on or to track the estimated first motor rate of change if the persistence counter exceeds the stall limit count; wherein the second motor controller further comprises a second speed control module for decreasing the target rotor speed of the second motor to be proportional to the first motor deceleration multiplied by an elapsed time, between the first time interval and the second time interval, plus a previous second rotor speed of the second motor. 13. The system according to claim 12 wherein the second motor controller further comprises a second speed control module for decreasing the target rotor speed to a fixed rotor speed at a respective motor input current subject to a corresponding current limit, wherein the target rotor speed is proportional to or equal to the observed first motor speed and wherein the motor input current is less than or equal to the current limit. 14. The system according to claim 12 wherein the target rotor speed of the second motor is decreased in accordance with the following equation: ω=ω0+αt, where α is the constant negative angular acceleration equal to the first motor deceleration, w is the target angular velocity of the second motor, and ω0 is previous second rotor speed, and t is elapsed time between the first time interval and the second time interval. 15. The system according to claim 12 wherein the target rotor speed of the second motor is modeled as a time integral to address time-varying angular acceleration in accordance with the following equation: ω(t)=ω0+∫0Tα(t)dt, where ω(t) is the target angular velocity of the second motor for a time within time period T, ω0 is an initial second rotor speed at T=0, α(t) is the negative angular acceleration or deceleration that is a function of time, and is equal to the absolute value of the first motor deceleration at a corresponding time. 16. The system according to claim 12 further comprising: the first motor and the second motor attached to a mower deck for rotating a first mower blade and a second mower blade, respectively, the first mower blade located proximate to a discharge chute of the mower deck;a first current monitor for detecting a first current draw of the first motor, where the first motor is subject to a variable load from cut material presented by both the first mower blade and the second mower blade;a first data processor for determining whether the first current draw is greater than a maximum allowable current draw;a second data processor of the second motor controller for sampling a second current draw of a second motor and an commanded versus observed speed of the second motor if the first current draw is greater than the maximum allowable current draw. 17. The system according to claim 12 further comprising: a first current monitor for detecting a first current draw of the first motor, where the first motor is subject to variable load and wherein the first motor and the second motor comprise components within a common assembly for cutting material, the first current monitor adapted to determine whether the first current draw is greater than a maximum allowable current draw;a second current monitor for detecting a second current draw of a second motor and an observed speed versus a commanded speed of at least one of the first motor and the second motor if the first current draw is greater than the maximum allowable current draw. 18. The system according to claim 12 further comprising: a first current monitor for detecting a first current draw of the first motor, where the first motor is subject to a variable load and wherein the first motor and the second motor comprise components within a common assembly for cutting material, the first current monitor adapted to determine whether the first current draw is greater than a maximum allowable current draw;the first speed monitor for determining an observed rotor speed of the first rotor of the first motor;a second current monitor for detecting a second current draw of a second motor and an observed speed of the second motor versus a commanded speed of the second motor if the first current draw is greater than the maximum allowable current draw and if the first observed rotor speed is less than a commanded rotor speed for a group of time intervals. 19. The system according to claim 12 further comprising: a second motor controller for generating a plurality of commanded speeds of a second rotor of a second electric motor for a third time interval and a fourth time interval within a series of time intervals;a second speed monitor for detecting a plurality of observed speeds of the second rotor for the third time interval and the fourth time interval, each one of the observed speeds corresponding to a respective commanded speed;the second data processor for determining a common denominator for fractional representations of the respective commanded speeds and a secondary numerator difference between the corresponding observed speeds for the third time interval and the fourth time interval, a second ratio formed by the secondary numerator difference and the common denominator for the first motor;the second persistence counter for incrementing a secondary persistence counter for the second motor if the second ratio increases during the series of time intervals; andthe second motor controller adapted to estimate a first motor deceleration or first motor rate of change in first rotor speed of the first motor if the second ratio exceeds a stall limit count, the second motor controller adapted to adjust a target rotor speed of a second motor based on the estimated first motor rate of change to counteract or oppose the first motor rate of change. 20. The system according to claim 12 wherein the first persistence counter for the first motor exceeds a stall limit value is indicative of the first motor approaching or being at a stall mode. 21. The system according to claim 16 wherein: the second data processor of the second motor controller adapted to determine the common denominator for fractional representations of the respective commanded speeds and a numerator difference between the corresponding observed speeds if a first current draw of the first motor is greater than a maximum allowable current draw, if a second current draw of the second motor is greater than a maximum allowable current draw, and if an observed speed is less than a commanded speed of the first motor for the first time interval and the second time interval.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.