Protection system for alternating current, battery powered electric traction motor vehicle
First Claim
1. A battery powered traction vehicle propulsion system comprising at least one alternating current (AC) adjustable speed electric traction motor, which can propel the vehicle, being connected to a source of controllable AC power that is responsive to a control signal for setting the value of power applied to the motor, and a function generator for producing the control signal in response to a command signal, said generator limiting the rate of change of the control signal and minimum and maximum values thereof, said minimum and maximum values being selectively variable in response to at least two preselected operating characteristics of the propulsion system in a manner whereby the maximum and minimum values are varied in response to that characteristic requiring the most restrictive motor operation.
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Accused Products
Abstract
A battery powered traction vehicle propulsion system uses an alternating current (AC) adjustable speed electric traction motor to propel the vehicle. The motor is connected to a source of controllable AC power that is responsive to a control signal for setting the value of power applied to the motor. A function generator produces the control signal in response to a command signal and limits the rate of change of the control signal and its minimum and maximum values. The minimum and maximum values are varied in response to preselected operating characteristics of the propulsion system, such as, for example, battery voltage, motor temperature, motor and vehicle speed and control system temperature.
93 Citations
11 Claims
- 1. A battery powered traction vehicle propulsion system comprising at least one alternating current (AC) adjustable speed electric traction motor, which can propel the vehicle, being connected to a source of controllable AC power that is responsive to a control signal for setting the value of power applied to the motor, and a function generator for producing the control signal in response to a command signal, said generator limiting the rate of change of the control signal and minimum and maximum values thereof, said minimum and maximum values being selectively variable in response to at least two preselected operating characteristics of the propulsion system in a manner whereby the maximum and minimum values are varied in response to that characteristic requiring the most restrictive motor operation.
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9. In a battery powered electric traction vehicle propulsion system comprising at least one alternating current (AC) adjustable speed electric traction motor which can propel the vehicle, the motor being connected to a source of controllable AC power that is responsive to a control signal for setting the value of power applied to the motor, the improvement comprising:
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a function generator for producing the control signal in response to a command signal, said generator limiting the rate of change of the control signal and minimum and maximum values thereof, said minimum and maximum values being variable in response to preselected operating characteristics of the propulsion systems; a battery voltage monitor having selectable upper and lower voltage limits, said monitor providing a signal to said function generator for varying one of said minimum and maximum values toward zero in response to battery voltage becoming less than or greater than said lower and upper limits, respectively; a motor temperature monitor for comparing a calculated motor temperature and a measured motor temperature to preselected temperature limits, said motor temperature monitor providing a signal to said function generator for varying said minimum and maximum values toward zero at a preselected rate when either said calculated or said measured temperature exceeds said temperature limit; a control temperature monitor for comparing measured power source temperature to a preselected maximum limit and for providing a signal to said function generator for varying one of said minimum and maximum values toward zero at a preselected rate when source temperature exceeds said maximum limit; and selection means for receiving each of said signals from said battery voltage monitor, said motor temperature monitor and said control temperature monitor, said selection means selecting a most restrictive signal from said received signals for application to said function generator for varying said maximum and minimum values. - View Dependent Claims (10, 11)
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Specification