Andres Ortiz Salazar

Analysis and Study of a Bearingless AC Motor Type Divided Winding, Based on a Conventional Squirrel Cage Induction Motor

This paper shows the analysis and study of a bearingless ac Motor type divided winding for a conventional squirrel cage induction motor, (IM). The conventional IM is used as a bearingless motor for artificial-lift oil proposes, allowing a reduction in maintenance and operation costs. The goal of this paper is improving electromagnetic forces performance, such as the Lorentz and Maxwell forces, allowing rotor positioning at the rotation axis. It was used a simulator based on the finite element method for acquiring load results for a 3,75 kW, 380 V, 4-poles, 60 Hz, 1.04 Nm, IM motor. Experimental results show that is possible to use a conventional IM as a bearingless motor, achieving a 80% efficiency. This paper presents simulated and experimental results that demonstrated the operation of the IM bearingless-type split coil built from a conventional induction motor.

A new bilinear generalized predictive control approach: Algorithm and results

Abstract In this paper a new approach of bilinear predictive control is presented. The approach is based in the Bilinear Generalized Predictive Control (BGPC), strategy that uses a time-step quasi-linearised NARIMAX model. In that approach, due to the used model, a prediction error exist, which increases with the prediction horizon, degrading the performance of that controller. Thus, in the present approach, a compensated model is used, whose compensation term depends of the prediction horizon. The algorithm and the results obtained in a example simulation are shown, evidencing that a new approach presents a better performance than the controller based on the quasi-linear model.

Magnetic Sensor Used to Detect Contamination of Insulating Oil in Motors Applied to Electrical Submersible Pump

This paper presents a solution for detecting contamination of insulating oil used in the artificial lift method of the oil-type electrical submersible pump (ESP), which indirectly protects the induction motor associated with that system. The objective of this sensor is to generate an alarm signal at just the moment when the contamination in the isolated oil is present. The prototype was designed to work in harsh conditions to reach a depth of 2000 m and temperatures up to 200°C. It used simulator software to define the mechanical and electromagnetic variables. Results of field experiments were performed to validate the prototype. The final results performed in an ESP system with a 60-HP motor showed a good reliability and fast response of the prototype.

FPGA based robust controller applied to a boost converter

This paper presents a way to control a DC-DC Boost converter by a robust controller embedded in a Field Programmable Gate Array (FPGA). Normally, when the converter works for some time, the converters inductive and capacitive components suffer heating, causing an increase on the converters output resistance. This problem changes the systems operating point, contributing directly in output power loss. The main objective of this work is to synthetize a robust controller embedded in FPGA that minimizes the effects of load variations and input voltage variations. The main objective of the controller is maintaining a constant voltage in the output load. The results showed that the robust control technique H∞ embedded in the FPGA minimized the effects of the uncertainties and the disturbances approximating the system output response to its operating point.

DSP utilization in radial positioning control of bearingless machine

This work presents the radial positioning control of a bearingless machine rotor that was supported by DSP (digital signal processor). The studied bearingless machine is a three-phase induction machine that presents divided stator windings, coiled rotor and it is in the vertical position. The radial positioning control needs precision and appropriated answer time what is obtained with the DSP easily. To the machine position control is used a proportional derivative each one for each direction that indicate the rotor displacement. To the machine position control is used a proportional derivative controller (PD) that is based on two sensor measurement, each one for each direction that indicate the rotor displacement. To the current control is used a proportional integrative controller (PI) that is also implemented in DSP which acts by measured information in the windings. The machine is supplied from six inverters, which works guided, by PWM (pulse width modulation) sign from the DSP. The control machine was accomplished in a common PC initially and this work contributes with the transition to the system controlled by a DSP showing a comparison between the two implementations.

QoS analysis of routing protocols in wireless sensor networks in the monitoring of wind farms

The rising global demand of energy and the scarcity of fossil fuels can be mentioned as factors that justify the investment in renewable energies sources in the world, such as the wind power. Wind power has tremendous potential to provide renewable energy without reliance on traditional fossil fuel technologies. Conditional monitoring of wind turbines can help to avert unplanned downtime due to component failure, and this can be done via low-cost wireless sensor networks. This paper presents the Quality of Service (QoS) analysis in the monitoring of wind farms by using Wireless Sensor Networks (WSNs) based on the IEEE 802.15.4 standard using hierarchical and flat routing protocols through a simulated environment in the presence and absence of faults in the nodes. The results presented in this paper will assist in choosing the best protocol that guarantees the best response time of the system and consequently, improving the safety margin, preventing accidents that can damage the equipment and cause huge losses.

CRYSEED: An automatic 8-bit cryptographic algorithm developed with genetic programming

In this paper a cryptographic algorithm optimized for wireless sensor networks is proposed and developed automatically using the technique of genetic programming. The proposed algorithm, CRYSEED, was developed considering the safety and computational efficiency, important to keep the algorithm fast, thus consuming less energy and increasing the autonomy of embedded networking devices. In genetic programming were used in the fitness function the metrics maximum deviation, irregular deviation and algorithm running time, to find a safe and fast algorithm. CRYSEED algorithm was compared with the AES, showing better performance in all aspects tested.

DSP based Fuzzy controller applied to a DC-DC Boost converter

This paper presents a Fuzzy controller applied to a DC-DC Boost converter in order to minimize the systems power loss effects by adjusting the duty cycle of the converter. The variation in the input voltage and the losses in the electronic components of the converter (load variations) are the main causes of these power losses. The main objective of the controller is to maintain a constant voltage at the load regardless of these losses. The Fuzzy controller was embedded on a Digital Signal Processor in order to have a great reliability and a faster system response. The results show that the Fuzzy control technique can be utilized to minimize the effects of the systems uncertainties and disturbances while keeping the systems output response in its operating point.

Performance analysis of a neural flux observer for a bearingless induction machine with divided windings

This study presents a performance analysis of a neural observer applied to speed and radial position controls of an induction-type bearingless motor with divided windings. The speed and radial control actions are carried out in conjunction with current control in the windings. The neural flux observer aims at compensating possible parametric variations of the machine caused by agents such as temperature or nucleus saturation. Control and estimation of flux are executed by a program developed in ANSI C language. The following resources were used in the DSP: the analog/digital converter, the PWM outputs and the RS-232 parallel and serial interfaces, which are responsible, respectively, for programming the DSP and capturing data using the supervisory system. Compared with a fixed parameter, the observer validates the proposed method.

Wireless Monitoring of Induction Machine Rotor Physical Variables

With the widespread use of electric machines, there is a growing need to extract information from the machines to improve their control systems and maintenance management. The present work shows the development of an embedded system to perform the monitoring of the rotor physical variables of a squirrel cage induction motor. The system is comprised of: a circuit to acquire desirable rotor variable(s) and value(s) that send it to the computer; a rectifier and power storage circuit that converts an alternating current in a continuous current but also stores energy for a certain amount of time to wait for the motor’s shutdown; and a magnetic generator that harvests energy from the rotating field to power the circuits mentioned above. The embedded system is set on the rotor of a 5 HP squirrel cage induction motor, making it difficult to power the system because it is rotating. This problem can be solved with the construction of a magnetic generator device to avoid the need of using batteries or collector rings and will send data to the computer using a wireless NRF24L01 module. For the proposed system, initial validation tests were made using a temperature sensor (DS18b20), as this variable is known as the most important when identifying the need for maintenance and control systems. Few tests have shown promising results that, with further improvements, can prove the feasibility of using sensors in the rotor.