Control of two PM linear motors with a single inverter: application to elevator doors

This work considers the control of two PM synchronous motors using a single inverter. The standard approach to the control of a PM synchronous motor is to use a single inverter which provides independent control of the direct and quadrature voltages (and therefore of the direct and quadrature currents) of the motor. Here, an approach is presented that provides independent torque control of two PM synchronous motors using a single inverter. In this approach, the quadrature current of each motor is controlled while it is shown that the direct current is uncontrollable. Both parallel and series connections of the two motors to the single inverter are considered and it is shown how the singularity of the controller can be avoided in each case. The methodology is applied to the control of elevator doors.