Hydraulically driven low reactance, large air gap permanent magnet generator and voltage regulation system for use therewith

摘要

An electric power generating system comprises a low reactance, large airgap permanent magnet generator driven by a hydraulic motor to generate a poly-phase AC output voltage. Because the permanent magnet generator is a low reluctance, large airgap machine, the output voltage regulation is low over the desired loading range of the system. The output voltage is controlled within acceptable limits by trimming the output speed of the hydraulic motor through the use of a servovalve. The control for the servovalve senses a parameter of output power and generates a speed control signal to compensate for deviations in the generator output. The system includes protection circuitry which monitors at least one parameter of the output power. This protection circuitry generates an output protection signal in response to a deviation in the monitored parameter which exceeds predetermined limits. In response to this signal, an on/off solenoid, which is coupled between the hydraulic motor and the external source of hydraulic power, terminates the flow of hydraulic power to the hydraulic motor. This results in a termination of the power generation by the permanent magnet generator. In one embodiment of the instant invention, the permanent magnet generator includes a second stator winding which is used to generate a second output voltage. A rectification circuit is coupled to this second output to transform the voltage produced thereon to a dc voltage to power dc loads.