Synchronous electric machines self-sensing fault detection
AssigneeCaterpillar Inc.
InventorsAhmed Khalil, Jackson Wai, Sajan Abdul
Life of this patent
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Abstract
Techniques are described to continuously calculate an inverter DC power of a synchronous machine, e.g., motor or generator, based on the individual phase currents, DC link voltage, and gate signals, which can be compared against the commanded mechanical power based of the estimated rotor speed and commanded torque. A controller can determine whether to shut down the inverter, such as the pulse width modulation (PWM), if the DC power is greater than a threshold value. Such a threshold can be defined to allow an acceptable position and speed estimation error margin.
Claims20
A control system for a synchronous machine having a stator and a rotor, the control system comprising:
- an inverter circuit configured to be coupled between the stator and a common bus, wherein the common bus is configured to be coupled with an electrical load;
- a controller configured for:
- determining an inverter DC power value based on a voltage of the common bus and a current of the common bus;
- determining a power command value based on an estimated rotational speed of the rotor and a commanded torque value;
- comparing the determined inverter DC power value and the determined power command value to a threshold value;
- and
- determining whether to turn off the inverter circuit based on the comparison.
A method of controlling a synchronous machine having a stator, a rotor, and controlled by an inverter circuit coupled between the stator and a common bus, wherein the common bus is coupled with an electrical load, the method comprising:
- determining an inverter DC power value based on a voltage of the common bus and a current of the common bus;
- determining a power command value based on an estimated rotational speed of the rotor and a commanded torque value;
- comparing the determined inverter DC power value and the determined power command value to a threshold value;
- and
- determining whether to turn off the inverter circuit based on the comparison.
A vehicle having a synchronous machine having a stator and a rotor, the vehicle comprising:
- a traction system mechanically coupled to the synchronous machine;
- an inverter circuit configured to be coupled between the stator and a common bus, wherein the common bus is configured to be coupled with an electrical load;
- a controller configured for:
- determining an inverter DC power value based on a voltage of the common bus and a current of the common bus;
- determining a power command value based on an estimated rotational speed of the rotor and a commanded torque value;
- comparing the determined inverter DC power value and the determined power command value to a threshold value;
- and
- determining whether to turn off the inverter circuit based on the comparison.
Dependencies are inferred from the claim text.