Solar photovoltaic module safety shutdown system
A PV system may be used in case of emergencies. Each individual photovoltaic module receives a signal to determine if it is allowed to be operational or must shut down. Modules by default are shut off and safe to handle, absent the signal and in the presence of light.
1. A photovoltaic system comprising:
a first photovoltaic module comprising a first module switch, the first photovoltaic module operatively coupled with a first circuit, the first circuit operatively coupled to an alternating current (AC) main panelboard;
a second photovoltaic module comprising a second module switch, the at least second photovoltaic module operatively coupled with the first photovoltaic module through the first circuit;
a second circuit operatively coupled with the first module switch and with the second module switch;
a System-Monitor device operatively coupled with the first circuit, the second circuit, and the AC main panelboard, the System-Monitor device comprising a manual switch, the System-Monitor device configured to generate a System-On signal and to feed the System-On signal to the first module switch and to the second module switch through the second circuit when the manual switch is in an on state;
wherein the first module switch is configured to disable the first photovoltaic module through one of shorting the first photovoltaic module and disconnecting the first photovoltaic module from the first circuit when the System-On signal is not received by the first module switch from the second circuit;
wherein the second module switch is configured to disable the second photovoltaic module through one of shorting the first photovoltaic module and disconnecting the first photovoltaic module from the first circuit when the System-On signal is not received by the second module switch from the second circuit.
2. The system of claim 1 wherein the manual switch is including a manually controlled and lockable switch with visual feedback to enable or disable the System-On signal.
3. The system of claim 1 wherein the System-Monitor device further comprises a sensor switch where the System-Monitor device is further configured to feed the System-On signal to the first module switch and to the second module switch through the second circuit when both the manual switch and the sensor switch are in the on state.
4. The system of claim 3 wherein the sensor switch comprises a sensor selected from the group consisting of motion, moisture, heat sensors, and any combination thereof.
5. The system of claim 1 , wherein the first module switch comprises a current limiting resistor that provides power to an opto-isolated FET driver integrated circuit, which provides a gate voltage to a FET wherein the FET is connected to the first circuit.
6. The system of claim 5 wherein an inherent capacitance of a gate of the FET stores enough charge to remain at a high enough voltage to allow the FET to remain on during an entire AC cycle of the System On signal.
7. The system of claim 6 including a resistor to protect the FET as the first module switch transitions from an on state to an off state and to drain the charge in time to avoid overheating due to power dissipation.
8. The system of claim 1 including a first isolation device comprised in the first module switch and a second isolation device comprised in the second module switch.
9. The system of claim 8 wherein the first isolation device and the second isolation device are one of a transformer and an optical isolator.
10. A photovoltaic system comprising:
a first photovoltaic module comprising a first module switch, the first photovoltaic module operatively coupled with a first circuit, the first circuit operatively coupled to an alternating current (AC) main panelboard;
a second photovoltaic module comprising a second module switch, the at least second photovoltaic module operatively coupled with the first photovoltaic module through the first circuit;
a second circuit operatively coupled with the first module switch and with the second module switch;
a System-Monitor device operatively coupled with the first circuit, the second circuit, and the AC main panelboard, the System-Monitor device comprising a sensor switch, the System-Monitor device configured to generate a System-On signal and to feed the System-On signal to the first module switch and to the second module switch through the second circuit when the sensor switch is in an on state;
wherein the first module switch is configured to disable the first photovoltaic module through one of shorting the first photovoltaic module and disconnecting the first photovoltaic module from the first circuit when the System-On signal is not received by the first module switch from the second circuit;
wherein the second module switch is configured to disable the second photovoltaic module through one of shorting the first photovoltaic module and disconnecting the first photovoltaic module from the first circuit when the System-On signal is not received by the second module switch from the second circuit.
11. The system of claim 10 , wherein the System-Monitor device further comprises a manual switch that is lockable.