Apparatus and method for measuring ground impedance of a circuit
AssigneeChargepoint, Inc.
InventorCarl F. Hagenmaier, Jr.
Life of this patent
Estimating the term…
Abstract
A ground continuity circuit is described. In one embodiment, a first voltage of a signal associated with an electrical line input to a circuit is measured with respect to a first resistance value of the circuit. A ground continuity test signal is asserted into the circuit that causes the resistance value of the circuit to change to a second resistance value. A second voltage of the signal is measured with respect to the second resistance value. A ground impedance value of the circuit is determined as a function of the first and second measured voltages and the first and second resistance values.
Claims15
A method, comprising:
- measuring, with respect to a first resistance value of a circuit, a first voltage of a signal associated with an electrical line input to the circuit, wherein a first set of one or more resistors provides the first resistance value of the circuit;
- asserting a ground continuity test signal into the circuit that causes a switch to close to change the resistance value of the circuit to a second resistance value by causing a second set of one or more resistors to be connected in parallel with the first set of resistors, wherein the second resistance value is lower than the first resistance value;
- measuring, with respect to the second resistance value, a second voltage of the signal associated with the electrical line input;
- and
- determining a ground impedance value of the circuit as a function of the first and second measured voltages and the first and second resistance values.
An apparatus, comprising:
- a first set of one or more resistors providing resistance to a circuit;
- a second set of one or more resistors connected in parallel with the first set of resistors by a switching mechanism, wherein the second set of resistors provides resistance to the circuit when the switching mechanism is closed and not when the switching mechanism is open;
- and
- a processor operable to:
- periodically assert a ground continuity test signal into the circuit for operating the switching mechanism, and
- determine a ground impedance value of the circuit based on a ratio between a first voltage measurement of the circuit when the switching mechanism is closed and a second voltage measurement of the circuit when the switching mechanism is open.
An apparatus, comprising:
- a means for measuring, with respect to a first resistance value of a circuit, a first voltage of a signal associated with an electrical line input to the circuit, wherein a first set of one or more resistors provides the first resistance value of the circuit;
- a means for asserting a ground continuity test signal into the circuit that causes a switch to close to change the resistance value of the circuit to a second resistance value by causing a second set of one or more resistors to be connected in parallel with the first set of resistors, wherein the second resistance value is lower than the first resistance value;
- a means for measuring, with respect to the second resistance value, a second voltage of the signal associated with the electrical line input;
- and
- a means for determining a ground impedance value of the circuit as a function of the first and second measured voltages and the first and second resistance values.
Dependencies are inferred from the claim text.