A split-wound induction motor design to improve the reliability of PWM inverter drives

Stator windings have been designed for the three-phase induction motor to protect the PWM inverter bridge against simultaneous-conduction fault currents. Rather than adding inductance in each inverter leg to control fault currents, the design lets the primary leakage inductance of the motor stator windings perform the fault current control function. Appropriate separation of the windings in the stator slots increases the protection afforded. A 4 kW, two-pole, squirrel-cage induction motor, together with a 5 kW MOSFET inverter drive switching at 20 kHz, illustrates that excellent motor performance is possible with the new winding configurations. The motor power rating and torque/slip curves obtained at various speed settings with the new drive are close to those of a motor using standard stator windings. The protection afforded by the windings is shown to increase with the motor power and voltage rating