High frequency injection-based high voltage interlock
First Claim
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1. A vehicle comprising:
- an electric machine; and
a controller programmed to apply a voltage to the electric machine corresponding to an injection current, a frequency of the injection current being a predetermined multiple of a switching frequency corresponding to a rate at which the voltage is changed, and, in response to amplitudes of positive and negative sequence voltages derived from the voltage being a predetermined amount greater than corresponding predetermined sequence voltage amplitudes that are based on parameters of the injection current and parameters of the electric machine, output an indicator for a loss of electric machine connection.
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Abstract
A power inverter for driving an electric machine is configured to apply a voltage to the electric machine based on a high-frequency injection current. Three phase currents are measured and input into a current controller. A voltage command output from the current controller is monitored using a discrete Fourier transform to determine a positive and negative sequence voltage of the voltage command. The sequence voltages are compared to expected positive and negative sequence voltages. A loss of connection diagnostic is output if a magnitude of the difference between the expected and actual sequence voltages is greater than a predetermined threshold.
8 Citations
17 Claims
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1. A vehicle comprising:
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an electric machine; and a controller programmed to apply a voltage to the electric machine corresponding to an injection current, a frequency of the injection current being a predetermined multiple of a switching frequency corresponding to a rate at which the voltage is changed, and, in response to amplitudes of positive and negative sequence voltages derived from the voltage being a predetermined amount greater than corresponding predetermined sequence voltage amplitudes that are based on parameters of the injection current and parameters of the electric machine, output an indicator for a loss of electric machine connection. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method comprising:
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causing, by a controller, a power inverter to output a voltage to an electric machine based on a measured current and a diagnostic injection current reference having a frequency that is a predetermined multiple of a switching frequency corresponding to a rate at which the voltage is changed; and indicating, by the controller, a loss of electric machine connection in response to positive and negative sequence voltage amplitudes derived from the voltage being greater than predetermined positive and negative sequence voltage amplitudes by a predetermined amount. - View Dependent Claims (8, 9, 10)
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11. A power inverter comprising:
a controller programmed to apply a voltage to an electric machine corresponding to an injection current and, in response to positive and negative sequence voltage amplitudes derived from the voltage being greater than corresponding predetermined sequence voltage amplitudes that are based on parameters of the injection current and parameters of the electric machine by a predetermined amount, output an indicator for a loss of electric machine connection to the power inverter, wherein a frequency of the injection current is a predetermined multiple of a switching frequency corresponding to a rate at which the voltage is changed. - View Dependent Claims (12, 13, 14, 15, 16, 17)
Specification