Thermal protection for AC traction motors using temperature estimations to calculate torque limits and blower speed requirements
First Claim
1. A thermal protection apparatus for an AC traction motor including a stator, a rotor, and an inverter, comprising:
- means for measuring ambient air temperature of the motor;
means for measuring atmospheric air pressure of the motor;
means for using the measured ambient air temperature and atmospheric air pressure values for estimating a plurality of temperatures in the AC traction motor;
means for calculating a plurality of motor torque limits imposed by the plurality of estimated temperatures; and
means for controlling the inverter by providing a signal comprising the lowest of the calculated plurality of motor torque limits to an inverter controller.
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Accused Products
Abstract
A thermal protection apparatus for an AC traction motor including a stator, a rotor, a blower fan, and an inverter includes measuring apparatus for measuring ambient air temperature of the motor and atmospheric air pressure of the motor. A computer is provided for using the measured ambient air temperature and atmospheric air pressure values for estimating a plurality of temperatures in the AC traction motor and for calculating a plurality of motor torque limits imposed by the plurality of estimated temperatures. A control system is provided for controlling the inverter by providing a signal comprising the lowest of the calculated plurality of motor torque limits to an inverter controller. The control system can also be used to calculate a plurality of blower speed requirements imposed by the plurality of estimated temperatures and set the blower speed of the motor to the highest of the calculated plurality of blower speed requirements.
48 Citations
13 Claims
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1. A thermal protection apparatus for an AC traction motor including a stator, a rotor, and an inverter, comprising:
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means for measuring ambient air temperature of the motor; means for measuring atmospheric air pressure of the motor; means for using the measured ambient air temperature and atmospheric air pressure values for estimating a plurality of temperatures in the AC traction motor; means for calculating a plurality of motor torque limits imposed by the plurality of estimated temperatures; and means for controlling the inverter by providing a signal comprising the lowest of the calculated plurality of motor torque limits to an inverter controller. - View Dependent Claims (2, 3)
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4. A method of controlling an inverter to provide thermal protection for an AC traction motor including a rotor and a stator comprising the steps of:
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starting the inverter; measuring ambient air temperature of the motor; measuring atmospheric air pressure of the motor; estimating a plurality of temperatures in the AC traction motor with the ambient air temperature and atmospheric air pressure values; calculating a plurality of motor torque limits imposed by the plurality of estimated temperatures; and controlling the inverter by providing a signal comprising the lowest of the calculated plurality of motor torque limits to an inverter controller. - View Dependent Claims (5, 6, 7)
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8. A thermal protection apparatus for an AC traction motor including a stator, a rotor, and a ventilating blower, comprising:
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means for measuring ambient air temperature of the motor; means for measuring atmospheric air pressure of the motor; means for using the measured ambient air temperature and atmospheric air pressure values for estimating a plurality of temperatures in the AC traction motor; means for calculating a plurality of blower speed requirements imposed by the plurality of estimated temperatures; and means for setting the blower speed of the motor ventilating blower to the highest of the calculated plurality of blower speed requirements. - View Dependent Claims (9, 10)
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11. A method of controlling a speed of a blower fan to provide thermal protection for an AC traction motor including a rotor and a stator comprising the steps of:
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starting the inverter; measuring ambient air temperature of the motor; measuring atmospheric air pressure of the motor; estimating a plurality of temperatures in the AC traction motor with the ambient temperature and atmospheric air pressure values; calculating a plurality of blower speed requirements imposed by the plurality of estimated temperatures; and setting the blower speed of the motor to the highest of the calculated plurality of blower speed requirements. - View Dependent Claims (12, 13)
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Specification