Rapid shutdown and safety disconnect for hybrid PV systems

Patent metadata

Field	Value
Publication number	US-9812869-B2
Application number	US-201615222785-A
Country	US
Kind code	B2
Filing date	Jul 28, 2016
Priority date	Mar 21, 2016
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Embodiments of the present disclosure describe an energy generation system including a rapid shutdown mechanism configured to prevent a flow of power from a photovoltaic (PV) array when activated, a battery pack comprising one or more power storage devices, and an inverter coupled to the rapid shutdown mechanism and the battery pack. The inverter includes anti-islanding relays configured to electrically disconnect the inverter from a utility grid when activated transfer relays configured to electrically disconnect the inverter from a load when activated, and a detection and initiation circuit coupled to the rapid shutdown mechanism, battery pack, anti-islanding relays, and transfer relays, where the detection and initiation circuit is configured to detect a triggering event and to activate the rapid shutdown mechanism, disable the battery pack, activate the anti-islanding relays, and activate the transfer relays in response to the detection of the triggering event.

First claim

What is claimed is:

1. An energy generation system comprising:
a first rapid shutdown mechanism configured to prevent a flow of power from a photovoltaic (PV) array when activated;
a first battery pack comprising one or more power storage devices;
a switch; and
a first inverter coupled to the first rapid shutdown mechanism, the switch, and the first battery pack, the first inverter comprising:
first anti-islanding relays configured to electrically disconnect the first inverter from a utility grid when activated;
first transfer relays configured to electrically disconnect the first inverter from a load when activated; and
a first detection and initiation circuit coupled to the first rapid shutdown mechanism, first battery pack, first anti-islanding relays, and first transfer relays, wherein the first detection and initiation circuit is configured to detect an activation of the switch and to activate the first rapid shutdown mechanism, disable the first battery pack, activate the first anti-islanding relays, and activate the first transfer relays in response to the detection of the activation of the switch, thereby preventing flow of power from the array into an external circuit in response to the detection of the activation of the switch.

2. The energy generation system of claim 1 , wherein the switch is a shut-off switch positioned proximate to a main utility panel.

3. The energy generation system of claim 1 , wherein the switch is a DC disconnect switch positioned inside or proximate to the first inverter.

4. The energy generation system of claim 1 , wherein the first rapid shutdown mechanism is further configured to prevent a flow of power from the first battery pack.

5. The energy generation system of claim 4 , wherein the first rapid shutdown mechanism is further configured to prevent a flow of power from all sources of the energy generation system.

6. The energy generation system of claim 1 , further comprising a second battery pack comprising one or more storage devices.

7. The energy generation system of claim 6 , wherein the detection and initiation circuit is further coupled to the second battery pack, and wherein the detection and initiation circuit is further configured to disable the second battery pack.

8. The energy generation system of claim 6 , further comprising a second inverter coupled to a second rapid shutdown mechanism and the second battery pack, the second inverter comprising:
second anti-islanding relays configured to electrically disconnect the second inverter from the utility grid when activated;
second transfer relays configured to electrically disconnect the second inverter from the load when activated; and
a second detection and initiation circuit coupled to the first detection and initiation circuit, second rapid shutdown mechanism, second battery pack, second anti-islanding relays, and second transfer relays, wherein the second detection and initiation circuit is configured to activate the second rapid shutdown mechanism, disable the second battery pack, activate the second anti-islanding relays, and activate the second transfer relays in response to a command signal from the first detection and initiation circuit upon the detection of the activation of the switch.

9. The energy generation system of claim 8 , wherein the first inverter is communicatively coupled to the second inverter.

10. The energy generation system of claim 9 , wherein the first detection and initiation circuit is communicatively coupled to the second detection and initiation circuit.

11. The energy generation system of claim 8 , further comprising a third battery pack comprising one or more storage devices coupled to the first inverter.

12. The energy generation system of claim 11 , further comprising a fourth battery pack comprising one or more storage devices coupled to the second inverter.

13. The energy generation system of claim 8 , wherein the first detection and initiation circuit is further coupled to the second battery pack, and wherein the first detection and initiation circuit is further configured to disable the second battery pack.

14. An energy generation system comprising:
a rapid shutdown mechanism configured to prevent a flow of power from a photovoltaic (PV) array when activated;
a battery pack comprising one or more power storage devices;
a battery switch coupled to the battery pack;
a shut-off switch;
an inverter coupled to the rapid shutdown mechanism, the shut-off switch, and the battery pack, wherein the switch is configured to electrically disconnect the battery pack from the inverter, the inverter comprising:
anti-islanding relays configured to electrically disconnect the inverter from a utility grid when activated;
transfer relays configured to electrically disconnect the inverter from a load when activated; and
a detection and initiation circuit coupled to the rapid shutdown mechanism, battery pack, anti-islanding relays, and transfer relays, wherein the detection and initiation circuit is configured to detect an activation of the shut-off switch and to activate the rapid shutdown mechanism, disable the battery pack, activate the anti-islanding relays, and activate the transfer relays in response to the detection of the activation of the shut-off switch; and

a DC disconnect switch coupled to the detection and initiation circuit, and configured to electrically disconnect the PV array and the battery pack when the DC disconnect switch activated.

15. The energy generation system of claim 14 , wherein the shut-off switch is external to the inverter.

16. The energy generation system of claim 15 , wherein the DC disconnect switch generates the triggering event upon activation.

17. A method of performing a rapid shutdown function for an energy generation system comprising:
detecting, by a detection and initiation circuit in an inverter, an occurrence of an activation of a switch; and
in response to the detection of the occurrence of the activation of the switch, sending, by the detection and the initiation circuit, a plurality of signals to:
a rapid shutdown mechanism to cease power flow from a PV array;
a battery pack to disable the battery pack;
anti-islanding relays to cease power flow from the inverter to a utility grid; and
transfer relays to cease power flow from the inverter to a load,

wherein the signals electrically isolate the inverter from the PV array, the battery pack, the utility grid, and the load.

18. The method of claim 17 , wherein the triggering event is an activation of a DC disconnect switch.

19. The method of claim 17 , wherein the triggering event is an activation of an external shut-off switch.

Assignees

• Solarcity Corp

Inventors

• Narla Sandeep

Classifications

• H02J3/381 Primary

  Dispersed generators · CPC title

• H02J2101/24

  Photovoltaics · CPC title

• H02J3/388

  Arrangements for the handling of islanding, e.g. for disconnection or for avoiding the disconnection of power · CPC title

• H02S40/32

  comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules · CPC title

• H02S40/38

  Energy storage means, e.g. batteries, structurally associated with PV modules · CPC title