Disconnection of a string carrying direct current power
First Claim
1. An apparatus comprising:
- a differential current sensor configured to measure differential current of at least one photovoltaic string of a plurality of photovoltaic strings, the differential current measured by comparing respective currents in a first direct current (DC) power line and a second DC power line that interconnect the at least one photovoltaic string to the plurality of photovoltaic strings;
a first switch connected in series with the first DC power line;
a second switch connected in series with the first DC power line and in parallel with the first switch, wherein the first switch is configured to allow more of a current to flow than the second switch; and
a controller circuit configured to operate the first switch or the second switch in response to a measurement of the differential current from the differential current sensor.
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Accused Products
Abstract
A direct current (DC) power combiner operable to interconnect multiple interconnected photovoltaic strings is disclosed. The DC power combiner may include a device adapted for disconnecting at least one photovoltaic string from the multiple interconnected photovoltaic strings, each photovoltaic string connectible by a first and second DC power line. The device may include a differential current sensor adapted to measure differential current by comparing respective currents in the first and second DC power lines. A first switch is connected in series with the first DC power line. A control module is operatively attached to the differential current sensor and the first switch. The control module may be operable to open the first switch when the differential current sensor measures the differential current to be greater than a maximum allowed current differential, thereby disconnecting the photovoltaic string from the interconnected photovoltaic strings.
1144 Citations
20 Claims
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1. An apparatus comprising:
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a differential current sensor configured to measure differential current of at least one photovoltaic string of a plurality of photovoltaic strings, the differential current measured by comparing respective currents in a first direct current (DC) power line and a second DC power line that interconnect the at least one photovoltaic string to the plurality of photovoltaic strings; a first switch connected in series with the first DC power line; a second switch connected in series with the first DC power line and in parallel with the first switch, wherein the first switch is configured to allow more of a current to flow than the second switch; and a controller circuit configured to operate the first switch or the second switch in response to a measurement of the differential current from the differential current sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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measuring a differential current by comparing current in a first DC power line to current in a second DC power line, the first DC power line and the second DC power line connecting at least one photovoltaic string to a plurality of photovoltaic strings; and switching, in response to the measuring, one or more of a first switch or a second switch, the first switch connected in series with the first DC power line and the second switch connected in series with the first DC power line and connected in parallel with the first switch, wherein the first switch is configured to allow more of a current to flow than the second switch. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification