Dynamic current limiting
First Claim
1. A method for producing commands for current comprising:
- generating a command for current; and
preventing the command from exceeding a limit dynamically determined as a function of power dissipation in a component estimated from a measured current level indicative of current in the component and as a function of a measured temperature proximate to the component.
3 Assignments
0 Petitions
Accused Products
Abstract
A system and method for generating commands for current subject to dynamic determinations of a limit. In one embodiment, the dynamically determined limit is a function of power dissipation in a component estimated from a measured current level and as a function of a measured temperature proximate to the component. In another embodiment, the limit is a lesser of two dynamically determined current levels. The system and method may be of particular use in a motor having limits determined with respect to a transistor and a motor winding. More particularly, estimated temperatures are established for a transistor and a motor winding for use in dynamically determining limits. Dynamic current limiting may be applied to a left and right wheeled vehicle such that the limit applied to both wheels is the lower of the limits dynamically determined for each wheel.
132 Citations
37 Claims
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1. A method for producing commands for current comprising:
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generating a command for current; and preventing the command from exceeding a limit dynamically determined as a function of power dissipation in a component estimated from a measured current level indicative of current in the component and as a function of a measured temperature proximate to the component. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a system issuing commands for current, the improvement comprising:
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dynamically determining a first level of current that will not overheat a first component; dynamically determining a second level of current that will not overheat a second component; and preventing the commands from requesting current in excess of any of the first and second dynamically determined levels. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. In a system issuing commands for motor current in a motor, the improvement comprising:
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dynamically determining a first limit as a function of measured motor current and as a function of a measured temperature proximate the motor; dynamically determining a second limit as a function of measured transistor current and as a function of measured temperature proximate the transistor; and preventing the commands for current from exceeding any of the first and second dynamically determined limits. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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27. A computer program product for use in controlling commands for motor current, the computer program product comprising a computer usable medium having computer readable code thereon, the computer readable program code including:
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program code for dynamically determining a first limit as a function of estimated temperature of a motor winding; program code for dynamically determining a second limit as a function of estimated temperature of a power transistor; and program code for preventing the commands for motor current from exceeding any of the first and second dynamically determined limits. - View Dependent Claims (28)
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29. A computer program product for use in controlling commands for motor current, the computer program product comprising a computer usable medium having computer readable code thereon, the computer readable program code including:
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program code for dynamically determining a first limit as a function of measured motor current and as a function of a measured temperature proximate the motor; program code for dynamically determining a second limit as a function of measured transistor current and as a function of measured temperature proximate the transistor; and program code for preventing the commands for current from exceeding any of the first and second dynamically determined limits. - View Dependent Claims (30)
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31. A control circuit for a motor comprising:
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motor windings; at least three power transistors providing current to said motor windings; a current sensor measuring at least one motor current; a temperature sensor measuring temperature of a heat sink in proximity to the motor; a processor responsive to the measured current and the measured temperature to calculate estimated temperature of the one of the at least three power switches, said processor further calculating estimated temperature of the motor winding and dynamically determining a current command limit as a function of estimated power switch temperature, a second current command limit as a function of estimated motor winding temperature and a lowest limit from among the first current command limit, the second current command limit and a fixed limit; and limiting current commands to said motor to no more than the dynamically determined lowest limit. - View Dependent Claims (32)
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33. A control circuit for a motor comprising:
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motor windings; at least three power transistors providing current to said motor windings; a current sensor measuring at least one power transistor current; a temperature sensor measuring temperature of a heat sink near at least one of the power transistors; a processor responsive to the measured current and the measured temperature to calculate estimated temperature of the one of the at least three power switches, said processor further calculating estimated temperature of the motor winding and dynamically determining a current command limit as a function of estimated power switch temperature, a second current command limit as a function of estimated motor winding temperature and a lowest limit from among the first current command limit, the second current command limit and a fixed limit; and limiting current commands to said motor to no more than the dynamically determined lowest limit. - View Dependent Claims (34)
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35. A method for producing commands for current in a device having a plurality of ground contacting members each ground contacting member separately driven by its respective motor, the method comprising:
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dynamically determining a current command limit for each respective motor, applying a lowest of the dynamically determined current command limits to each of the respective motors so that current commands to each of the respective motors are subject to the same current command limit. - View Dependent Claims (36, 37)
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Specification