High Performance Control of AC Drives with Matlab / Simulink Models

8.4 MRAS-based Sensorless Control of Five-phase Induction Motor Drive

Sensorless operation of a vector controlled three-phase drive is widely discussed in the literature; however, this is not true for multi-phase AC machines, where a limited number of publications have appeared in the literature [25–27,59]. One of the most popular solutions is the MRAS, which is similar to three-phase drives [29–36].

As was shown in Chapter 6, multi-phase machine models can be transformed into an orthogonal frame of decoupled equations. The d-q reference frame contributes to torque and flux production. Hence, in rotor field oriented control (FOC), the rotor flux linkage is kept in the d-axis so that the q component of the rotor flux is zero. Thus, the produced torque and the rotor flux can be controlled independently by the d and q components of the stator current. The decoupled control of the torque and flux using the rotor flux oriented control for a five-phase IM is illustrated in Chapter 6.

This section focuses on the MRAS-based sensorless control of a five-phase IM, with current control in the stationary reference frame. A PI controller is used to compensate the rotor speed in the adaptive model. Phase currents are controlled using the hysteresis current control method.

The difference between the five-phase machine model, given in Chapter 6, and the three-phase machine model is the presence of x-y component. Motor x-y components are fully decoupled from d-q components, in addition to the one ...