Safety Switch for Photovoltaic Systems

Patent metadata

Field	Value
Publication number	US-2023223897-A1
Application number	US-202318184992-A
Country	US
Kind code	A1
Filing date	Mar 16, 2023
Priority date	Apr 5, 2016
Publication date	Jul 13, 2023
Grant date	—

Abstract

Various implementations described herein are directed to a methods and apparatuses for disconnecting, by a device, elements at certain parts of an electrical system. The method may include measuring operational parameters at certain locations within the system and/or receiving messages from control devices indicating a potentially unsafe condition, disconnecting and/or short-circuiting system elements in response, and reconnection the system elements when it is safe to do so. Certain embodiments relate to methods and apparatuses for providing operational power to safety switches during different modes of system operation.

First claim

1 - 25 . (canceled)

26 . An apparatus comprising:
first and second connectors; an auxiliary power supply circuit having an output, and an input coupled between the first connector and the second connector, wherein the auxiliary power supply circuit is configured to convert a first direct current (DC) voltage at a first amplitude received at the input to a second DC voltage at a second amplitude at the output, wherein the second amplitude is greater than the first amplitude; and a switch comprising a switchable DC serial path connected between the first and the second connectors, and a control terminal connected to the output of the auxiliary power supply circuit.

27 . The apparatus of claim 26 , wherein the switch is configurable into:
in response to the control terminal receiving the second DC voltage, an ON state that connects the switchable DC serial path between the first connector and the second connector, and in response to the control terminal not receiving the second DC voltage, an OFF state that disconnects the switchable DC serial path.

28 . The apparatus of claim 27 , wherein the auxiliary power supply circuit is configured to:
receive communication signals; and based on the communication signals, enable and disable the second DC voltage to control the switch into the ON state and the OFF state.

29 . The apparatus of claim 28 , wherein the communication signals are received as power line communication signals via the first connector or the second connector.

30 . The apparatus of claim 29 , wherein the power line communication signals comprise alternating-current signals over the first connector or the second connector.

31 . The apparatus of claim 27 , wherein the auxiliary power supply circuit is configured to:
convert the first direct current (DC) voltage at the first amplitude of between 15-200 millivolts when the switch is in the ON state.

32 . The apparatus of claim 27 , wherein, when in the ON state, the switch has a current-voltage relationship that causes the first amplitude to be between 15-200 millivolts when 10 amperes pass through the switchable DC serial path.

33 . The apparatus of claim 27 , wherein the auxiliary power supply circuit is configured to generate the second DC voltage at the second amplitude sufficient to maintain the switch in the ON state, while the first DC voltage at the first amplitude is between 15-90 millivolts.

34 . The apparatus of claim 27 , wherein the auxiliary power supply circuit is configured to:
receive a keep alive signal via the first connector or the second connector; maintain the switch in the ON state based on receiving the keep alive signal; and control the switch into the OFF state based on an absence of the keep alive signal.

35 . The apparatus of claim 26 , wherein the auxiliary power supply circuit is configured to cease generating the second DC voltage based on a serial current flowing between the first and the second connectors through the switchable DC serial path falling below a threshold level.

36 . The apparatus of claim 26 , wherein the switch comprises a transistor connected, via an emitter or source terminal, and a collector or drain terminal, between the first and the second connectors, and the control terminal comprises a base or a gate terminal of the transistor.

37 . The apparatus of claim 36 , wherein the auxiliary power supply circuit comprises:
a communication circuit configured to receive power line communication signals on the first connector or the second connector; and a controller circuit configured to, based on the power line communication signals, control the second amplitude to control the transistor into an ON state and into an OFF state.

38 . The apparatus of claim 37 , wherein the controller circuit is configured to, in response to the power line communication signals, vary the second amplitude between a first value of less than 2 volts and a second value of greater than 5 volts.

39 . The apparatus of claim 36 , wherein the auxiliary power supply circuit is configured to:
convert a drain-to-source voltage across the drain terminal and the source terminal of the transistor to a gate-to-source voltage applied to the gate terminal, wherein the gate-to-source voltage is greater than the drain-to-source voltage when the switch is in an ON state; or convert an emitter-to-collector voltage across the emitter terminal and the source terminal of the transistor to a base-to-emitter voltage applied to the base terminal, wherein the base-to-emitter voltage is greater than the emitter-to-collector voltage when the switch is in the ON state.

40 . The apparatus of claim 26 , further comprising a diode having a cathode connected to the first connector and an anode connected to the second connector.

41 . The apparatus of claim 26 , further comprising a resistor connected between the first connector and the second connector and in parallel with the switch.

42 . The apparatus of claim 26 , wherein the first and the second connectors are designed to mate with third, and fourth connectors, respectively, which are designed to connect to each other.

43 . A system comprising:
a photovoltaic string comprising a pair of photovoltaic generators and a safety switch coupled in series;
wherein the safety switch comprises:
first and second connectors connecting the safety switch inline between the pair of photovoltaic generators;
an auxiliary power supply circuit configured to convert a first direct current (DC) voltage at a first amplitude between the first and the second connectors to a second DC voltage at a second amplitude on an output terminal, wherein the second amplitude is greater than the first amplitude; and
a switch circuit comprising a switchable DC serial path connected between the first and the second connectors, and a control terminal connected to the output terminal of the auxiliary power supply circuit; and

a power device comprising:
a power converter having inputs connected across the photovoltaic string, and
a control circuit configured to control photovoltaic power generated by the photovoltaic string.

44 . A method comprising:
receiving, between first and second connectors of a safety switch, power; converting, with an auxiliary power supply circuit in the safety switch, a first direct current (DC) voltage at a first amplitude received between the first and the second connectors to a second DC voltage at a second amplitude, wherein the second amplitude is greater than the first amplitude; and applying, with the auxiliary power supply circuit, the second DC voltage to a control terminal of a switch comprising a switchable DC serial path connected between the first and the second connectors.

45 . A method comprising:
controlling a power converter from a first mode of operation that extracts photovoltaic power from a photovoltaic string according to a maximum power point tracking (MPPT) algorithm, to a second mode of operation that ceases to draw the photovoltaic power,
wherein the photovoltaic string comprises a pair of photovoltaic generators and a safety switch coupled in series, and wherein the safety switch comprises:
first and second connectors connecting the safety switch inline between the pair of photovoltaic generators;

converting, with an auxiliary power supply circuit in the safety switch, a first direct current (DC) voltage at a first amplitude between the first and second connectors to a second DC voltage at a second amplitude on an output

Assignees

• Solaredge Technologies Ltd

Inventors

• Loewenstern Yakir
• Yoscovich Ilan
• Braginsky David
• Glovinsky Tzachi
• Assia Izak
• Shkoury Roy

Classifications

• H02S40/34 Primary

  comprising specially adapted electrical connection means to be structurally associated with the PV module, e.g. junction boxes · CPC title

• H02M3/158

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02S50/10

  Testing of PV devices, e.g. of PV modules or single PV cells (testing of semiconductor devices during manufacturing {H10P74/00}) · CPC title

• H02S40/36

  characterised by special electrical interconnection means between two or more PV modules, e.g. electrical module-to-module connection · CPC title

• Y02E10/56

  Power conversion systems, e.g. maximum power point trackers · CPC title