Ground monitor
AssigneeLear Corporation
InventorsDavid A. Hein, Aftab Ali Khan
Life of this patent
Estimating the term…
Abstract
A ground monitor is disclosed. The ground monitor may be configured to conduct a ground continuity test based on a determined ground resistance. The ground monitor may be operable to determine the ground resistance as a function of a voltage differential detected during application of a test current.
Claims20
A charging system operable with a vehicle to facilitate charging the vehicle with energy provided from a three-pronged wall outlet of a domestic power network, the system comprising:
- a three-pronged terminal operable to connect to each of a neutral plug, a hot plug, and a ground plug of the wall outlet;
- an power circuit operable to manipulate energy received at the three-pronged terminal for use in charging the vehicle;
- a signal generator operable to transmit a plurality of test currents having one or more characteristics to the wall outlet, the signal generator being further operable to vary the one or more characteristics of the plurality of test currents;
- and
- a controller operable to determine a ground resistance of the domestic power network based on a detected voltage differential across at least two of the terminals during the transmission of the plurality of test currents;
- the controller being further operable to select the one or more characteristics of the plurality of test currents and to assess a quality of the detected voltage differential for identifying the one or more characteristics of the plurality of test currents that result in a most reliable assessment of the ground resistance;
- and
- the controller operable to prevent the power circuit from charging the vehicle in the event the ground resistance is greater than a predefined threshold while the ground resistance was assessed during application of the plurality of test currents having the one or more characteristics identified to result in the most reliable assessment.
A ground monitor being operably coupled to a three-pronged outlet having a hot plug, a neutral plug, and a ground plug of an AC power network to detect a ground resistance of the network based on a voltage differential between the neutral plug and the ground plug of the outlet, the ground monitor comprising:
- a signal generator operable to apply a test current to the neutral plug at a first frequency, wherein the hot plug of the outlet receives a current flowing therethrough at a second frequency and the first frequency is different from the second frequency;
- a filter being operable to remove signals having the second frequency and to output a filtered signal;
- and
- a voltage sensor operable to measure a voltage differential between the neutral and ground plugs based on the filtered signal, the voltage differential representing the ground resistance during application of the test current.
A ground monitor operable with a three-pronged outlet of an AC power network to detect a ground resistance of the network according to a voltage differential between a neutral plug and a ground plug of the outlet, comprising:
- a signal generator operable to apply an impulse test current to the neutral plug a particular instance in time during which a current flowing to the hot plug is within a predefined zero-crossing range;
- and
- a voltage sensor operable to measure a voltage differential between the neutral and ground plugs during the particular instance in time, the voltage differential representing the ground resistance during application of the test current.
Dependencies are inferred from the claim text.