Estimation of rotor flux of an induction machine

The objective of this dissertation is to estimate rotor flux of an IM. Some of the material is focused on the functional block of the IM i.e. Torque estimator, Speed estimator etc. while a subsequent part deals with estimation of rotor flux. The dissertation is organized as follows:Chapter 1 describes background information of the machines then it focuses on the methodology how on to approach the task on a particular time with the help of Gantt chart.Chapter 2 presents the basic principals of rotating magnetic field of the IM and asserts brief overview of the AC machines. Later it talks about different kinds of IM rotors suggesting which one is good. It is crucial to start with good and appropriate reviews which were verified by numerous journals. Literature review is presented by analysing the previous work. (Busawan et al., 2001) summarises that a nonlinear observers for the estimation of the rotor flux and the load torque in an induction motor. The observers are designed on the basis of the standard alpha - beta Park's model. Finally, fuzzy logic is mentioned in more detailed way and Membership functions were also discussedChapter 3 explains the dynamic model of induction machine plant and the model was presented. Then the model is analysed, developed in MATLAB-SIMULINK which was discussed in Chapter 4. By considering following assumptions, dynamic model is implemented i.e. it should be symmetrical two-pole, three phase windings. Slotting effects are neglected, Permeability of the iron part is infinite, and iron losses are neglected. Dynamic d-q model and Axes transformation is implemented on stationary reference frame (a-b-c). Lastly torque equation is derived.Chapter 4 is the heart of this project by scrutinizing the model thoroughly and by introducing fuzzy controller logic using MATLAB-SIMULINK; simulations are performed to estimate the functional block such as torque, speed, flux, resistance with and without fuzzy logic. Results were obtained for different blocks and the m-file, DTC, Flux table were obtained and presented in the Appendixes.Chapter 5 concludes the simulation results and concentrates mainly on the future direction what more can be done to improve the platform in a more efficient manner

Nonlinear Time-Frequency Control of Permanent Magnet Electrical Machines

Permanent magnet (PM) electrical machines have been widely adopted in industrial applications due to their advantages such as easy to control, compact in size, low in power loss, and fast in response, to name only a few. Contemporary control methods specifically designed for the control of PM electrical machines only focus on controlling their time-domain behaviors while completely ignored their frequency-domain characteristics. Hence, when a PM electrical machine is highly nonlinear, none of them performs well. To make up for the drawback and hence improve the performance of PM electrical machines under high nonlinearity, the novel nonlinear time-frequency control concept is adopted to develop viable nonlinear control schemes for PM electrical machines. In this research, three nonlinear time-frequency control schemes are developed for the speed and position control of PM brushed DC motors, speed and position control of PM synchronous motors, and chaos suppression of PM synchronous motors, respectively. The most significant feature of the demonstrated control schemes are their ability in generating a proper control effort that controls the system response in both the time and frequency domains. Simulation and experiment results have verified the effectiveness and superiority of the presented control schemes. The nonlinear time-frequency control scheme is therefore believed to be suitable for PM electrical machine control and is expected to have a positive impact on the broader application of PM electrical machines

Integrated Optimal Design of a Passive Wind Turbine System: An Experimental Validation

This work presents design and experimentation of a full passive wind turbine system without active electronic part(power and control). The efficiency of such device can be obtained only if the system design parameters are mutually adapted through an Integrated Optimal Design (IOD) method. This approach based on multiobjective optimization, aims at concurrently optimizing the wind power extraction and the global system losses for a given wind speed profile while reducing the weight of the wind turbine generator. It allows us to obtain the main characteristics (geometric and energetic features) of the optimal Permanent Magnet Synchronous Generator (PMSG) for the passive wind turbine. Finally, experiments on the PMSG prototype built from this work show a good agreement with theoretical predictions. This validates the design approach and confirms the effectiveness of such passive device

Advanced Control of the Permanent Magnet Synchronous Motor

The electrical machines are the core of the electrical drives. By introducing the vector control techniques for the alternative current machines, the high performances in drive systems are attained. One on the alternative current machines is the permanent magnet synchronous motor (PMSM). Due to their advantages, it becomes a very popular solution in the electrical drive field. In this chapter, an optimal control solution applied on the PMSM based on the Riccati solution is developed by the author. The objectives of the optimal control drive system are regulation, stability, robustness to the load disturbance variation and the energy reduction. Comparative with the conventional cascaded control, the proposed solution conducts up to 10% to energy efficiency improvement in transient regimes. The efficiency improvement depends on the chosen weighted matrices. Both the conventional and optimal controllers are implemented in Matlab-Simulink. The real-time solution based on the dSpace platform is provided

Grey Fuzzy Sliding Mode Control with Grey Estimator for Brushless Doubly Fed Motor

In this paper, a grey fuzzy sliding mode controller (GFSMC) for brushless doubly fed motor (BDFM) adjustable speed system is presented. A grey model estimator and adaptive fuzzy control technology are incorporated into the sliding mode control (SMC) to adaptively regulate the adaptive law of SMC. The proposed adaptive fuzzy equivalent controller, adaptive fuzzy switching controller, and grey model compensation controller for BDFM can eliminate the average chattering encountered by most SMC schemes, improve the robustness, and obtain excellent static and dynamic performances of SMC. Simulation results show that the proposed control strategy is feasible, correct and effective

Rotor field orientation speed and torque control of BDFM with adaptive second order sliding mode

This paper presents two cascaded second order sliding mode controllers (SOSMCs) for brushless doubly fed motor (BDFM) adjustable speed system, which regulate the speed and torque. And an adaptive super twisting algorithm is incorporated into the SOSMCs to adaptively regulate the law of SOSMC. The proposed controllers for BDFM eliminate the average chattering encountered by most sliding mode control (SMC) schemes, and also possess the robustness and excellent static and dynamic performances of SMC. Simulation results show that the proposed control strategy is feasible, proper and effective. © 2013 IEEE

Analysis and Simulation of Direct Torque Controlled Induction Motor Drive

The vector control study of an induction motor countenances the decoupled analysis. In this control torque and flux components are independently controlled (just as in dc motor). This simplifies the analysis compared to the per phase equivalent circuit. The major disadvantage of flux vector control is the required insertion of the pulse encoder. The other disadvantage is that torque is indirectly controlled rather than directly. Lastly, a delay in signal of input references and resultant stator voltage vector is introduced because of presence of the PWM modulator. The last two factors prevent the eventual capability of vector control to attain high express flux and torque control. Direct torque control (DTC) of an induction motor fed by a voltage source inverter is a modest scheme that does not need lengthy computation time and can be implemented without pulse encoders and is unresponsive to parameter variations. The objective is to control efficiently torque and flux. This procedure estimates motor flux and torque by sampling and analyzing motor terminal voltages and currents. A voltage vector is nominated to have flux and torque errors within boundaries, built on estimations of flux position and amount of instantaneous errors in torque and stator flux. This method made the motor control more accurate and fast, highly dynamic speed response and simple to control. The reference value can be evaluated using the flux and torque estimated and motor parameters. The effectiveness of the Direct Torque Control scheme was verified by simulation using MATLAB/SIMULINK®