Modulating Inverter System for Variable-Speed Induction Motor Drive (GM Electrovair II)

The induction motor control system of the battery- powered Electrovair II, where a thyristor (controlled rectifier) modulating inverter supplies the three-phase variable frequency and modulates the voltage level as required by the induction motor is described. Electrovair I, which preceded Electrovair II, used separate power circuits to perform the functions of voltage-level control and frequency generation.