Patent ID: 8970183
Filing Date: 2015-03-03
Classification: H02H,H02M,H02P

Abstract:
1. A generator comprising: a permanent magnet generator, an exciter and a main generator mounted for rotation on a shaft, the main generator configured to produce a voltage output; a generator control unit including a circuit configured to provide current from the permanent magnet generator to the exciter; a switch provided in the circuit and configured to change between open and closed conditions, the switch configured to flow current in the circuit in the closed condition and interrupt current flow in the open condition; an overvoltage limit controller programmed to determine an amount of overvoltage of the output voltage exceeding a specified voltage, use a fixed reference threshold voltage or use a varying reference threshold voltage based upon the duration of overvoltage, and modulate the switch between the open and closed conditions according to a voltage error between the output voltage and the reference threshold voltage to limit the output voltage to a desired voltage; and wherein the generator control unit includes an exciter field driver, and comprising an exciter controller configured to receive the point of regulation voltage and provide a desired voltage/current command signal to the exciter field driver to achieve the desired voltage, the overvoltage limit controller configured to modulate the switch in response to a faulty desired voltage command signal.