Dynamic Modelling And Implementation Of Split-Phase Induction Machine

ABSTRACT

Multiphase induction machine offers numerous advantages compared to the

conventional three phase induction machine. It is an upgrade from the conventional

three phase induction machine. By splitting the phase belt of a three phase, a sixphase

machine is realised. The areas of application of multiphase machines are

enormous, mostly where reliability is paramount. This research presents the

modelling and implementation of a split phase induction machine with Saturation

and skin effects incorporated for submarine application. A three phase

asynchronous machine is reconfigured and converted into a six-phase with same

size as the original machine. No load, Blocked rotor and Retardation tests were

carried out on the sample machine to determine machine parameters. MATLAB

software was employed for the simulation of the developed models. The simulation

results are presented and discussed. Comparison of the models representing

different operating conditions is also presented. The results of the study show that

the six phase machine has an improved torque of 84-Nm compared to 64-Nm of the

three phase. The stator phase currents in the six phase is reduced by 50 percent

compared to the three phase machine. The results also show that the phase currents

settling time in the three phase and six phase is 0.4secs and 0.2secs respectively.

The mechanical rotor speed of the three and six phase reaches synchronism in

0.3secs and 0.6secs respectively. The torque settling time is 0.6secs and 0.5secs

respectively. The efficiency of the two motors are also compared, and the results

show that the three and six phase motors is 84 percent and 88 percent respectively.

This shows a 4 percent improvement in motor efficiency, and translates to reduction

in energy demand by this machine. It important to point out here that multiphase

induction machine will soon replace the traditional three phase network.