Permanent magnet alternator speed detection circuit with feedback at lower speeds

摘要

A permanent magnet alternator is driven by a turbine engine to supply three phases of power to a control circuit for the engine. A shunt regulator delivers current to the control circuit, and a voltage supply is also included to deliver power for a period of time as the alternator is gaining speed at startup. A speed detection circuit detects the speed of the shaft for diagnostic purposes and a feedback circuit overrides a control for the supply of the current at lower speeds such that the speed detection circuit will be accurate even at lower speeds.