Surge Protection Circuit for Power MOSFETs used as Active Bypass Diodes in Photovoltaic Solar Power Systems

摘要

A protection circuit for metal-oxide-semiconductor field-effect transistors (MOSFETs) that are used as active bypass diodes in photovoltaic solar power systems is disclosed. The protection circuit comprises, a detection circuit for detecting the start of a surge event, a switch disposed to connect the MOSFET's drain to it's gate in response to the start of the surge, a diode in series with the switch, a bistable circuit for keeping the switch closed during the surge, and a means of resetting the bistable circuit after the surge.

主权项

1. A protection circuit for protecting a metal-oxide-semiconductor field-effect transistor from electrical surges, comprising:
a switch for coupling the drain of the metal-oxide-semiconductor field-effect transistor to the gate of the metal-oxide-semiconductor field-effect transistor; a diode in series with the switch for preventing current flow from the gate of the metal-oxide-semiconductor field-effect transistor to the drain of the metal-oxide-semiconductor field-effect transistor; a bistable circuit for controlling the switch, the switch being closed whilst the bistable circuit is set and open whilst the bistable circuit is reset; detection circuit for setting the bistable circuit in response to the voltage difference between the drain and source of the metal-oxide-semiconductor field-effect transistor being relatively greater than a first predefined voltage threshold; and a means for resetting the bistable circuit in response to the voltage difference between the drain and source of the metal-oxide-semiconductor field-effect transistor being relatively lesser than a second predetermined voltage threshold.