An implementation of rotor speed observer for sensorless induction motor drive in case of machine parameter uncertainty

The paper describes observers using model reference adaptive system for sensorless induction motor drive with the pulse width modulator and the direct torque control under the circumstances of incorrect information of induction motor parameters. An approximation based on the definition of the Laplace transformation is used to obtain initial values of the parameters. These values are utilized to simulate sensorless control structures of the induction motor drive in Matlab-Simulink environment. Performance comparison of two typical observers is carried out at different speed areas and in presence of parameter uncertainty. A laboratory stand with the induction motor drive and load unit is set up to verify the properties of observers. Experimental results confirm the expected dynamic properties of selected observer

Half-duplex energy harvesting relay network over different fading environment: System performance with effect of hardware impairment

In this paper, we introduce a half-duplex (HD) energy harvesting (EH) relay network over the different fading environment with the effect of hardware impairment (HI). The model system was investigated with the amplify-and-forward (AF) and the power splitting (PS) protocols. The system performance analysis in term of the outage probability (OP), achievable throughput (AT), and bit error rate (BER) were demonstrated with the closed-form expressions. In addition, the power splitting (PS) factor was investigated. We verified the analytical analysis by Monte Carlo simulation with all primary parameters. From the results, we can state that the analytical and simulation results match well with each other.Web of Science911art. no. Unsp 228

Speed estimators using stator resistance adaptation for sensorless induction motor drive

The paper describes speed estimators for a speed sensorless induction motor drive with the direct torque and flux control. However, the accuracy of the direct torque control depends on the correct information of the stator resistance, because its value varies with working conditions of the induction motor. Hence, a stator resistance adaptation is necessary. Two techniques were developed for solving this problem: model reference adaptive system based scheme and artificial neural network based scheme. At first, the sensorless control structures of the induction motor drive were implemented in Matlab-Simulink environment. Then, a comparison is done by evaluating the rotor speed difference. The simulation results confirm that speed estimators and adaptation techniques are simple to simulate and experiment. By comparison of both speed estimators and both adaptation techniques, the current based model reference adaptive system estimator with the artificial neural network based adaptation technique gives higher accuracy of the speed estimation

Pulse-width modulation direct torque control induction motor drive with Kalman filter

The paper deals with application of Kalman filter in induction motor drive using pulse-width modulation direct torque control (PWM-DTC). In the first part, the conventional PWM-DTC drive is described and Kalman filter is utilized to filter components of stator current vector those are assumed to be disturbed by white noise. The second part contains simulation results that are obtained in different cases of load torque, process and measurement noise covariances. The integral time absolute error (ITAE) performance index, undershoot, ripple of important quantities are used to compare the conventional drive structure and proposed drive structure with Kalman filter. The simulation results confirm the expected dynamic response of the proposed structure

Evaluating the initial result of transanal and transvaginal NOTES for colorectal cancer

Objective: Natural Orifice Transluminal Endoscopic Surgery (NOTES) is an important evolution in minimally invasive surgery (MIS) nowaday. This paper presents the techniques and early results of the pure transanal and transvaginal laparoscopies (NOTES) used for the treatment of colorectal cancer. Material and method: Prospective studies were conducted at Hue Central Hospital, Vietnam. Patients: From December 2013 to September 2015, 22 cololorectal cancer patients (18 rectum, 3 sigmoid tumors and 1 descending colon), adenocarcinoma, T≤ T3N1M0. Methods: The patients were placed in lithotomy and Trendelenburg positions, and the lone-star retractor was placed in the anus (rectum cancer) or vagina (sigmoid cancer). The surgical cavity was then inflated with CO 2 and set at 12 mm/Hg. Dissection was continued until inside of the abdominal cavity (transanal technique). After that, the rectum was pushed into the abdominal cavity. The IMA and IMV were divided (TME included) in both techniques. After finishing dissection, the specimens were pulled out through the anus or vagina to prepare anastomosis. Coloanal and colorectal anastomosis were either hand-sewn (6 cases) or sealed with EEA staplers (16 cases). Results: 2 patients needed one more 5 mm umbilical port in RLQ, 2 patients needed two 5 mm trocars (post radiation hemorrhage, and urethral perforation). One patient converted to open and 1 patient converted to the HYBRID-NOTES procedure. The operation time was 258±40 (190-300) minutes. All patients required minimal analgesia. Bowel movement returned on the first day to 16 patients (average: two days, maximum: three days). The hospital stay was 7±2.8 (4-14) days. Kirwan classification (sphincter function) was very good (stage I: 18). Conclusions: Pure transanal and transvaginal laparoscopies for the treatment of colorectal cancer are feasible and safe. We believe that this is the first pure transvaginal laparoscopy (NOTES) for human in the world. A multicentric study in a large numbers of patients and a long follow-up is necessary

Aplikace řízení v klouzavém režimu v pohonu s asynchronním motorem

Induction motors, as well as electrical drives, are widely used in industry applications and consume a large number of electrical energy in the world. Energy saving, torque fast response and speed accuracy are main area in controlling induction motors. During last years, control methods have been developed to get these goals. Among these control methods, field - oriented control (FOC) is more and more popular because of high performance, energy saving, controlled acceleration, etc. However, in controlling AC machine drive by using FOC, the motor speed is required. Together with the development of semiconductor technologies and digital signal processing (DSP), software instruments have been used to estimate speed, reducing hardware complexity and cost of a mechanical speed sensor. However, due to the nonlinearity, high order and multivariable properties of induction motor dynamics, the development of advanced induction motor control is still a challenging task. In this research proposal, basic description of the torque and flux control, as well as the theory and application of sliding mode algorithms are reviewed in details. From that, a sliding mode control algorithms for speed control is proposed to implement the pulse width modulation with a constant switching frequency. In addition, the sliding mode observer for speed estimation is investigated. The parameter sensitivity of the observer and controller are analyzed. Furthermore, the robustness of control and observer algorithms are also proved by Lyapunov’s criterion. Simulation models and control structures in MATLAB – Simulink environment are developed to verify the performance of the proposed algorithms. Finally, the experimental work in an induction motor drive controlled by eZdspTMF28335 is presented to compare with theoretical assumptions and simulation results.Induction motors, as well as electrical drives, are widely used in industry applications and consume a large number of electrical energy in the world. Energy saving, torque fast response and speed accuracy are main area in controlling induction motors. During last years, control methods have been developed to get these goals. Among these control methods, field - oriented control (FOC) is more and more popular because of high performance, energy saving, controlled acceleration, etc. However, in controlling AC machine drive by using FOC, the motor speed is required. Together with the development of semiconductor technologies and digital signal processing (DSP), software instruments have been used to estimate speed, reducing hardware complexity and cost of a mechanical speed sensor. However, due to the nonlinearity, high order and multivariable properties of induction motor dynamics, the development of advanced induction motor control is still a challenging task. In this research proposal, basic description of the torque and flux control, as well as the theory and application of sliding mode algorithms are reviewed in details. From that, a sliding mode control algorithms for speed control is proposed to implement the pulse width modulation with a constant switching frequency. In addition, the sliding mode observer for speed estimation is investigated. The parameter sensitivity of the observer and controller are analyzed. Furthermore, the robustness of control and observer algorithms are also proved by Lyapunov’s criterion. Simulation models and control structures in MATLAB – Simulink environment are developed to verify the performance of the proposed algorithms. Finally, the experimental work in an induction motor drive controlled by eZdspTMF28335 is presented to compare with theoretical assumptions and simulation results.430 - Katedra elektronikyvyhově

Application of BEMF-MRAS with Kalman filter in sensorless control of induction motor drive

This paper describes an induction motor speed estimation using the observer with back electromotive force-based model reference adaptive system and Kalman filter. In the first part of the paper, there is a mathematical description of the rotor speed observer. The second part of the paper includes Kalman filter that is used for the filtration of measured stator currents and obtaining their time derivatives. The third part contains a description of the laboratory workplace with the induction motor drive and active load unit that was used for an experimental verification of the rotor speed observer. The last section of the paper shows experimental results that were obtained for different changes in the induction motor speed. The experimental results confirmed expected dynamic properties of the induction motor drive with sensorless control.Web of Science9941160115

Application of Sensorless Sliding Mode Observer in Control of Induction Motor Drive

Induction motors are widely used in an industry and it is necessary to improve control methods for induction motors to increase the efficiency of them. In this paper, sliding mode controllers are proposed instead of traditional PI controllers in vector control of induction motor drives. Moreover, rotor speed is estimated by a sliding mode observer. In addition, the robustness of control and observer algorithms are also proved by Lyapunov’s criterion. The experiments are obtained in different speed changes of an induction motor drive. These experimental results confirm the dynamic properties of a sensorless sliding mode control of an induction motor drive

Performance Analysis in DF Energy Harvesting Full-Duplex Relaying Network with MRC and SC at the Receiver under Impact of Eavesdropper

This paper investigates the decode-and-forward (DF) full-duplex (FD) relaying system under the presence of an eavesdropper. Moreover, the relay node is able to harvest energy from a transmitter, and then it uses the harvested energy for conveying information to the receiver. Besides, both two-hop and direct relaying links are taking into consideration. In the mathematical analysis, we derived the exact expressions for intercept probability and outage probability (OP) by applying maximal ratio combining (MRC) and selection combining (SC) techniques at the receiver. Next, the Monte Carlo simulation is performed to validate the mathematical analysis. The results show that the simulation curves match the mathematic expressions, which confirms the analysis section

Extended second order sliding mode control for mismatched uncertain systems with only output measurable

Most existing Second Order Sliding Mode Control (SOSMC) approaches are achieved under assumptions that 1) all of state variables must be accessible; 2) the second derivative of all state variables must exist, even though mathematical model of systems uses the first order equations. In this paper, a new adaptive SOSMC scheme is proposed for mismatched uncertain systems in which these above assumptions are required. In this proposed method, only output variables are used in the sliding surface and controller design. The advantage of no need of all state variables in controller design makes the method more useful and realistic since it can be applied to a wider class of systems. Finally, a vertical take-off and landing aircraft at the nominal airspeed of 135~knots is simulated to demonstrate the advantages and effectiveness of the proposed approach