Adaptive demagnetization compensation for a motor in an electric or partially electric motor vehicle
First Claim
1. A hybrid electric vehicle comprising:
- a first motor coupled to wheels of the hybrid electric vehicle;
a second motor coupled to wheels of the hybrid electric vehicle;
a first voltage monitor coupled to the first motor to determine a first permanent magnet induced voltage of the first motor;
a controller that;
compares the first permanent magnet induced voltage with a first reference voltage that reflects an expected permanent magnet induced voltage for the first motor when a permanent magnet of the first motor is fully magnetized;
determines a state of magnetism of the permanent magnet of the first motor based on the first permanent magnet induced voltage, the first reference voltage and a predetermined speed at which the first permanent magnet induced voltage is determined;
makes the first motor inoperable if the state of magnetism of the permanent magnet of the first motor reaches a predetermined threshold; and
causes wheels of the vehicle to be driven with the second motor after the first motor is made inoperable.
4 Assignments
0 Petitions
Accused Products
Abstract
In an electric or hybrid electric vehicle, a voltage monitor (102) is directly coupled to a traction motor (38) and/or generator motor (30) to detect a permanent magnet induced voltage within the motor at a predetermined speed and no load condition (300). A controller (100) compares the detected permanent magnet induced voltage with an expected reference voltage that represents an expected permanent magnet induced voltage at full magnetization and the predetermined speed (302). The controller produces an indication of magnetization based on the reference voltage, the detected permanent magnet induced voltage, and the predetermined speed. If the indication of magnetism reaches a predetermined threshold, the motor is made inoperable and/or a current to the motor is limited to prevent damage to components (306, 308, 310, 312, 314). Preferably, a user of the vehicle is made aware of these actions by an audible and/or visual indicator (308, 314). If available, another source of motive power is substituted for the motor that is made inoperable (316).
20 Citations
18 Claims
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1. A hybrid electric vehicle comprising:
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a first motor coupled to wheels of the hybrid electric vehicle;
a second motor coupled to wheels of the hybrid electric vehicle;
a first voltage monitor coupled to the first motor to determine a first permanent magnet induced voltage of the first motor;
a controller that;
compares the first permanent magnet induced voltage with a first reference voltage that reflects an expected permanent magnet induced voltage for the first motor when a permanent magnet of the first motor is fully magnetized;
determines a state of magnetism of the permanent magnet of the first motor based on the first permanent magnet induced voltage, the first reference voltage and a predetermined speed at which the first permanent magnet induced voltage is determined;
makes the first motor inoperable if the state of magnetism of the permanent magnet of the first motor reaches a predetermined threshold; and
causes wheels of the vehicle to be driven with the second motor after the first motor is made inoperable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
a second voltage monitor coupled to the second motor to determine a second permanent magnet induced voltage of the second motor.
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9. The vehicle of claim 8 wherein the processor:
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compares the second permanent magnet induced voltage with a second reference voltage that reflects an expected permanent magnet induced voltage for the second motor when a permanent magnet of the second motor is fully magnetized;
determines a state of magnetism of the permanent magnet of the second motor based on the second permanent magnet induced voltage, the second reference voltage, and a predetermined speed at which the second permanent magnet induced voltage is determined;
makes the second motor inoperable if the state of magnetism of the permanent magnet of the second motor reaches a predetermined threshold; and
causes wheels of the vehicle to be driven with the first motor after the second motor is made inoperable.
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10. The vehicle of claim 9 wherein the first voltage monitor comprises a sensor coil that detects the first permanent magnet induced voltage that is induced by rotation of a rotor that includes the permanent magnet of the first motor and wherein the second voltage monitor comprises a sensor coil that detects the second permanent magnet induced voltage that is induced by rotation of a rotor that includes the permanent magnet of the second motor.
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11. The vehicle of claim 9 wherein the first motor is a generator motor and the second motor is a traction motor.
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12. The vehicle of claim 11 wherein the generator is coupled to an internal combustion engine by planetary gears.
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13. The vehicle of claim 9 wherein the first motor is a traction motor and the second motor is a generator coupled to planetary gears.
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14. The vehicle of claim 13 wherein the generator is coupled to an internal combustion engine by the planetary gears.
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15. A method for compensating for permanent magnet degradation in a hybrid electric vehicle that includes a first motor coupled to rotate wheels of the hybrid electric vehicle and a second motor coupled to rotate wheels of the hybrid electric vehicle, the method comprising the steps of:
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determining a state of magnetism of a first permanent magnet in the first motor;
determining whether the state of magnetism has reached a predetermined threshold;
making the first motor inoperable if the state of magnetism has reached the predetermined threshold; and
causing the second motor to rotate wheels of the hybrid electric vehicle if the first motor is made inoperable. - View Dependent Claims (16, 17, 18)
detecting a voltage induce in a coil in a stator of the first motor when the motor is at a no load condition; and
comparing the voltage with an expected voltage that reflects an induced voltage when the first permanent magnet is fully magnetized.
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17. The method of claim 15 wherein the first motor is a generator coupled to an internal combustion engine and the second motor is a traction motor.
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18. The method of claim 15 wherein the first motor is a traction motor and the second motor is a generator motor coupled to an internal combustion engine, and wherein the method further comprises causing the internal combustion engine to rotate wheels of the vehicle after the second motor causes the hybrid electric vehicle to reach a predetermined speed.
Specification