Overvoltage snubber for grid tie inverter

An overvoltage snubber circuit configured to receive an alternating current (AC) overvoltage, comprising:

• a first rectifier configured to convert the AC overvoltage to a direct current (DC) overvoltage;
• a chopper circuit electrically connected to the first rectifier and configured to break up the DC overvoltage and to output a variable DC voltage;
• and
• a resistor electrically connected to the chopper circuit and configured to dissipate energy of the variable DC voltage,
• wherein the first rectifier is electrically connected to the resistor and configured to convert the variable DC voltage to a snubbed AC voltage,
• wherein the overvoltage snubber circuit is located in a fuel cell system comprising:
• a plurality of fuel cell modules are electrically connected to an inverter and configured to convert a DC voltage output of the plurality of fuel cell modules to an AC voltage,
• an electrical grid circuit breaker electrically connected to an electrical grid and configured to interrupt an electrical connection between the inverter and the electrical grid,
• a load configured to receive the AC voltage from the electrical grid and the inverter,
• an electrical bus configured to transmit the AC voltage, and configured to electrically connect the inverter, the electrical grid circuit breaker, the load, and the overvoltage snubber circuit in parallel, and
• wherein the overvoltage snubber circuit further comprises:
• the first rectifier electrically connected to the electrical bus on an AC side of the first rectifier and electrically connected to a positive bus and a negative bus on a DC side of the first rectifier,
• a pre-charge circuit electrically connected between the positive bus and the negative bus and electrically connected in parallel to an input of the chopper circuit via the negative bus, and
• the resistor having a first and a second end, the first end of the resistor electrically connected to an output of the chopper circuit and the second end of the resistor electrically connected to the positive bus.