Contribucion al control de motores de reluctancia autoconmutados

Abstract

In this thesis contributions are made to the Electronic Control of the Switched Reluctance Motors (SRM) to a given margin of power between 0.25 -10 kW. Following a brief historical introduction to SRMs, the SRM is placed in the context of the electric drives, its constitution, its model, and afterward its principles of operation are then analyzed. Following this a relationship between its advantages and drawbacks are then carried out along with its commercial applications and future expectations. Secondly, after a brief review on the state-of-the-art of SRM controls, several structures of power converter used in these types of drives are studied. Then different alternatives to the current and position/speed sensing are described. Subsequently, the different control strategies, likely to be applied to the average torque in SRM, are presented as well as the different implementing possibilities to the afore-mentioned control strategies. Thirdly, a low-cost drive of the SRM which permits regulation of speed with constant commutation angles is proposed. The control of this drive has been built by means of analogical and digitally discrete components. With respect to the sensors, a single current sensor has been used and the position/speed sensor has been build by means of three optical-interrupters and a slotted disc. Regarding the basics of this drive, we have studied how some motor parameters such as efficiency and acoustic noise have been influenced by the different strategies of control which were mainly built by different types of regulators (Pulse-Width Modulation PWM, Hysteresis, PWM with current regulation) with some characteristic parameters focusing on the motors operation, such as efficiency and acoustic noise. Fourth, a platform is presented for a design of the digital SRM drives by using as a base the Dspace Ace kit 1104 CLP. On this platform, three distinct alternative averaging torque controls have been developed for SRM starting from the signals coming from three optical-interrupters. The first alternative consists of an online control of the turn-on and turn-off angles for variable speed applications which does not depend on curves of magnetization but on a few parameters of the motor. The turn-on angle is calculated through Boses law and the turn-off angle is calculated through Gribbles turn-off angle theory. The second alternative consists of a control that includes a performance turn off optimizer in which starting from the turn-on and turn-off conduction obtained from the aforementioned control modifying itself online by means of an algorithm in order to minimize input power and maximize performance. The third alternative tries to maximize efficiency from a table, experimentally obtained, which picks up the turn-on and turn-off angles minimizing the drive input power in distinct operational zones with margins of speed pre-established. An efficiency and electrical consumption comparison between the results obtained applying different digital control alternatives and with a commercial vector-controlled induction motor drive of the same size is included. The influence of different digital control alternatives that optimize efficiency on torque ripple and acoustic noise is also studied. Finally, all the contributions were brought together, final conclusions presented and a summary of future lines of work offered.