Ground fault detection system
First Claim
Patent Images
1. A ground fault detection system comprising:
- A single optocoupler connected to a second voltage source, a current sink, a first node at a ground zero reference level, and a second node at around;
wherein said current sink comprises;
a first resistor; and
a first transistor;
wherein said current sink is electrically connected in series between said optocoupler and a terminal of a battery pack comprising one or more battery units, andwherein a first voltage source. that provides a potential below the lowest potential of a battery pack, is connected in series between said current sink and said battery pack,wherein the first voltage source is connected to a negative terminal of a battery unit,wherein a first node at a zero reference level is an enclosure around portion of said battery pack; and
wherein upon connection between a battery unit to said first node, current flows through the optocoupler and the current sink to cause the optocoupler to output a ground fault detection signal to an output node, and whereby the output node is electrically connected with said second node, and whereby said second node is electrically isolated from said first node;
whereby current only flows through the ground fault detection system when the battery is electrically grounded.
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Abstract
The present application describes, among other things, a ground fault detection system. The system includes an optocoupler, a current sink, and a first voltage source connected in series. The first voltage source can connect to a negative terminal of a battery unit. Upon connection between a positive terminal of the battery unit and a first node at a ground zero reference level, current can flow through the optocoupler and the current sink to cause the optocoupler to output a ground fault detection signal.
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Citations
17 Claims
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1. A ground fault detection system comprising:
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A single optocoupler connected to a second voltage source, a current sink, a first node at a ground zero reference level, and a second node at around; wherein said current sink comprises; a first resistor; and a first transistor; wherein said current sink is electrically connected in series between said optocoupler and a terminal of a battery pack comprising one or more battery units, and wherein a first voltage source. that provides a potential below the lowest potential of a battery pack, is connected in series between said current sink and said battery pack, wherein the first voltage source is connected to a negative terminal of a battery unit, wherein a first node at a zero reference level is an enclosure around portion of said battery pack; and wherein upon connection between a battery unit to said first node, current flows through the optocoupler and the current sink to cause the optocoupler to output a ground fault detection signal to an output node, and whereby the output node is electrically connected with said second node, and whereby said second node is electrically isolated from said first node;
whereby current only flows through the ground fault detection system when the battery is electrically grounded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A ground fault detection system comprising:
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optocoupler with a light emitting diode and a transistor; wherein said optocoupler is connected to a second voltage source, a current sink, a first node at a ground zero reference level, and a second node at ground; a current sink comprising; a first resistor; and a first transistor; wherein the current sink is connected to the light emitting diode of the optocoupler; and a first voltage source with a negative terminal connected to the current sink and a positive terminal connected to a negative terminal of a battery unit; wherein upon connection between a positive terminal of the battery unit and a chassis of an electric vehicle, i) current flows through the light emitting diode of the optocoupler and the current sink, and ii) the light emitting diode activates the transistor such that the optocoupler outputs a ground fault detection signal.
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17. A method of detecting a ground fault comprising:
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a) providing a ground fault detection system comprising; a single optocoupler connected to a second voltage source, a current sink, a first node at a ground zero reference level, and a second node at ground; wherein said current sink comprises; a first resistor; and a first transistor; wherein said current sink is electrically connected in series between said optocoupler and a terminal of a battery pack comprising out or more battery units, and wherein the first voltage source that provides a potential below the lowest potential of a battery back is connected in series between said current sink and a negative terminal of the battery unit, wherein said first node, at a zero reference level, is an enclosure around a portion of said battery pack; and wherein upon connection between a battery unit and said first node, current flows through said optocoupler and the current sink to cause the optocoupler to output a ground fault detection signal to an output node, and whereby the output node is electrically connected with said second node, and whereby said second node is electrically isolated from said first node; whereby current only flows through the ground fault detection system when the battery is electrically grounded; b) connecting a positive terminal of said first voltage source to said negative terminal of said battery unit to said first node at a ground zero reference level; c) flowing said current through a light emitting diode of said optocoupler and a current source; and d) activating a transistor of said optocoupler such that said optocoupler outputs said ground fault detection signal.
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Specification