Sinusoidal control of a 6/4 variable reluctance machine without rotor position sensor

This paper presents the control of a 6/4 variable reluctance machine, without any rotor position sensor. The energizing of each of the three stator phases of the machine is done by means of sinusoidal AC power supplies. The nominal frequency is 50 Hz. Two main cases were considered for this purpose. The first one implies AC voltage sources and the other one refers to AC current sources. The situations when either positive or both alternations of the waveforms corresponding to these sources are also considered. Moreover, the situations when this waveforms have a phase angle of either 60 degrees or 120 degrees (related to each other), are also considered. Adjusting the angular velocity of the rotor is automatically achieved, according to the nominal operating frequency of the power supplies and also depending on the energizing type of the stator phases respectively. This is achieved only after a prior establishment to a certain value of the initial angular speed of the rotor. The initial rotor angular velocity is therefore calculated in advance. Thereby, two main rotor angular speeds are considered: 78.5 rad/s and 157 rad/s respectively (for the same operating frequency of the power supply, depending on how the stator phases are energized). The adjustment of the stator phase current is carried out either by adjusting the current supplied by the current sources, or through resistors in case of the voltage sources. Results of simulations using the software package Matlab - Simulink are presented at the end of this paper.