Electrical system for turbine/alternator on common shaft

An electrical system for a turbine/alternator comprising a gas driven turbine and permanent magnet alternator on a common shaft comprising:

• a) said alternator having a permanent magnet rotor and a stator winding;
• b) an AC bus connected to the stator winding;
• c) an AC output circuit;
• d) an inverter connected to the AC output circuit;
• e) a first contactor for connecting the inverter to the AC bus;
• f) a DC bus connected to the inverter;
• g) a rectifier connected between the AC bus and the DC bus;
• h) a temporary power supply connected to the DC bus;
• i) a driver connected to cause switching of the inverter;
• j) a signal generator driven by signals derived from the rotation of the common shaft;
• k) an open loop waveform generator;
• l) a second contactor for connecting either the signal generator or the open loop waveform generator to the inverter;
• and
• m) a system controller for during a startup mode switching the first contactor to connect the inverter circuit to the AC bus and switching the second contactor to connect the signal generator to the driver and during a power out mode switching the first contactor to disconnect the inverter from the AC bus and switching the second contactor to connect the open loop waveform generator to the driver;
• whereby during the startup mode, the alternator functions as a motor to raise the speed of the turbine to a safe ignition speed and in the power out mode the electrical system outputs to the AC output circuit, AC electric power having a frequency unrelated to the rotational speed of the alternator.