Protective device for a photovoltaic system

Patent metadata

Field	Value
Publication number	US-9780550-B2
Application number	US-201313957569-A
Country	US
Kind code	B2
Filing date	Aug 2, 2013
Priority date	Feb 2, 2011
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A protective device for a photovoltaic system includes at least one input for connection to a photovoltaic generator and at least one output for delivery of an electric power supplied from the photovoltaic generator. The protective device includes a detection device for a signal applied via the at least one output, and is configured to provide a low level-limited voltage at the at least one output if an applied signal does not meet a predetermined criteria, and is further configured to connect the at least one output with low resistance to the at least one input via a switching device if the applied signal meets the predetermined criteria.

First claim

The invention claimed is:

1. A protective device for a photovoltaic system, comprising:
at least one input configured to connect to a photovoltaic generator;
at least one output configured to deliver electric power supplied by the photovoltaic generator;
a detection device configured to receive a signal applied at the at least one output, wherein the protective device is configured to provide a low level-limited voltage at the at least one output when the applied signal does not meet a predetermined criteria, and wherein the protective device is further configured to connect the at least one output to the at least one input via a switching device when the applied signal meets the predetermined criteria;
a DC-DC converter, a series regulator, a shunt regulator, or a further input configured to receive a partial voltage from the photovoltaic generator to generate the low level-limited voltage; and
a timer configured to delay control of the switching device such that a switching of the switching device takes place only if the applied signal meets the predetermined criteria for more than a predetermined period of time.

2. The protective device according to claim 1 , wherein the detection device comprises a current measuring device configured to measure a current at the at least one output, wherein the applied signal is associated with a magnitude of the current.

3. The protective device according to claim 2 , wherein the predetermined criteria is related to a magnitude of the current, wherein the protective device is configured to provide the low level-limited voltage at the at least one output if the current is less than a lower threshold, and further configured to connect the at least one output to the at least one input via the switching device if the current is greater than or equal to an upper threshold, wherein the upper threshold is greater than or equal to the lower threshold.

4. The protective device according to claim 2 , wherein the current measuring device comprises a shunt for current measurement and a threshold switch.

5. The protective device according to claim 1 , wherein the detection device comprises a voltage measuring device configured to measure a voltage at the at least one output, wherein the applied signal is associated with a level of the voltage.

6. The protective device according to claim 1 , wherein the predetermined criteria corresponds to a temporal modulation of the signal.

7. The protective device according to claim 1 , wherein the low level-limited voltage is connected to the at least one output exhibiting a high impedance via a series resistor.

8. The protective device according to claim 1 , wherein the low level-limited voltage is connected to the at least one output via a diode.

9. The protective device according to claim 1 , wherein the switching device comprises a semiconductor switch.

10. The protective device according to claim 1 , further comprising an arc detection component configured to detect an electric arc connected to the switching device for control thereof.

11. The protective device according to claim 10 , wherein the arc detection component is connected to the switching device such that the switching device opens if an electric arc is detected.

12. The protective device according to claim 10 , wherein the arc detection component comprises a band-pass filter and an envelope detector.

13. A protective device for a photovoltaic system, comprising:
at least one input configured to connect to a photovoltaic generator;
at least one output configured to deliver electric power supplied by the photovoltaic generator;
a detection device configured to receive a signal applied at the at least one output, wherein the protective device is configured to provide a low level-limited voltage at the at least one output when the applied signal does not meet a predetermined criteria, and wherein the protective device is further configured to connect the at least one output to the at least one input via a switching device when the applied signal meets the predetermined criteria; and
a DC-DC converter, a series regulator, a shunt regulator, or a further input configured to receive a partial voltage from the photovoltaic generator to generate the low level-limited voltage,
wherein the detection device comprises a current measuring device configured to measure a current at the at least one output, wherein the applied signal is associated with a magnitude of the current,
wherein the current measuring device comprises a shunt for current measurement and a threshold switch, and
wherein the threshold switch exhibits a switching hysteresis.

14. The protective device according to claim 13 , wherein the low level-limited voltage is connected to the at least one output exhibiting a high impedance via a series resistor.

15. The protective device according to claim 13 , wherein the low level-limited voltage is connected to the at least one output via a diode.

16. The protective device according to claim 13 , wherein the switching device comprises a semiconductor switch.

17. The protective device according to claim 13 , further comprising an arc detection component configured to detect an electric arc connected to the switching device for control thereof.

18. The protective device according to claim 17 , wherein the arc detection component is connected to the switching device such that the switching device opens if an electric arc is detected.

19. The protective device according to claim 17 , wherein the arc detection component comprises a band-pass filter and an envelope detector.

20. An operating method for a protective device of a photovoltaic system that comprises at least one input configured to connect to a photovoltaic generator and at least one output configured to deliver the electric power supplied by the photovoltaic generator, comprising:
applying a low level-limited voltage to the at least one output;
monitoring the at least one output for a presence of a signal and, if applicable, detecting a present signal;
applying an operating voltage to the at least one output for delivery of a total electric power supplied by the photovoltaic generator, if a detected signal meets a predetermined criteria using a switching device,
applying the low level-limited voltage to the at least one output if there is no signal present or if the detected signal does not meet the predetermined criteria using the switching device;
generating the low level-limited voltage by a DC-DC converter, a series regulator, a shunt regulator, or receiving a partial voltage from the photovoltaic generator at a further input; and
using a timer to delay control of the switching device such that a switching of the switching device takes place only if the detected signal meets the predetermined criteria for more than a predetermined period of time.

21. The operating method according to claim 20 , wherein the predetermined criteria is related to an operating state of an inverter of the photovoltaic system that is transmitted by means of a temporal modulation of the signal.

22. The operating method according to claim 20 , wherein the predetermined criteria is related to a magnitude of a current at the at least one output, and wherein the at least one output is supplied with the operating voltage, if the current is greater than or equal to an upper threshold and with the low level-limited voltage if the output current is less than a lower threshold, wherein the lower threshold is less t

Assignees

• Sma Solar Technology Ag

Inventors

• Hopf Markus
• Victor Matthias
• Greizer Frank
• Bettenwort Gerd
• Friebe Jens

Classifications

• Y10T307/858

  Cross-Sectional Technologies · mapped topic

• Y10T307/865

  Cross-Sectional Technologies · mapped topic

• Y02E10/50

  Photovoltaic [PV] energy · CPC title

• H02H3/02 Primary

  Details · CPC title

• Y10T307/766

  Cross-Sectional Technologies · mapped topic