Angle Control Method Research Articles

Robust flux angle control of induction motors to improve efficiency at light loads

AbstractVector control of induction motors has provided us with both good performance and acceptable efficiency at rated loads. Using this method at light loads reduces the efficiency due to the adjustment of motor flux at the rated value. Electric motors are normally used even at lower loads than the rated ones and often selected oversized. Enhancing the efficiency of induction motors at light loads will significantly reduce electric energy consumption. A novel method called Flux Angle Control (FAC) of the induction motor is presented to improve efficiency in the steady state at light loads. To increase the accuracy of the induction motor model we consider iron losses. This method controls the angle between the stator flux (stator current) and the d‐axis (rotor flux direction). The primary aim of the flux angle control method is to reduce the flux level and increase the flux angle at light loads. The optimal flux angle is sensitive to some induction motor parameters. The proposed method offers several advantages compared to similar methods, including high efficiency, minimal sensitivity of the optimal flux angle to changes in motor parameters, a reduced number of calculations, and easy implementation. The validity of this method is examined through experiments.

Integrated control strategy for the vibration mitigation of wind turbines based on pitch angle control and TMDI systems

Modern wind turbines are becoming taller and more slender to gather wind energy more efficiently and are increasingly installed in complex environments. Consequently, the new generations of wind turbines are prone to vibration-related problems, making the development of vibration control strategies important. Various pitch angle control methods and dynamic vibration absorbers (DVAs) have been proposed recently to reduce the aerodynamic forces and structural responses of wind turbines. However, these approaches are often implemented independently, limiting the effectiveness of the overall control strategy. In this paper, pitch angle control and DVAs are integrated to improve the performance of wind turbines in a complex environment. Firstly, a simplified eight degree-of-freedoms (DOFs) model of the wind turbine is developed using Lagrange’s Equation, and the wind turbine is linearized at specific operating points. The NREL 5MW wind turbine is taken as a benchmark model with strategies based on a proportional–integral (PI) pitch controller. Secondly, the pitch angle of each blade is adjusted by the combination of disturbance accommodating control (DAC) and linear quadratic gaussian (LQG) controller considering the wind speed disturbances. Additionally, the tuned mass damper with inerter (TMDI) is adopted to further suppress the structural vibrations. Thirdly, the passive and active methods of TMDl integrated with the pitch controller are investigated. Lastly, the effectiveness of the integrated control strategies is assessed when the wind turbines are subjected to earthquake and wind loads. The results indicate that combining active pitch control and TMDI can improve the power generation performance of wind turbines by reducing structural responses and damage-equivalent loads, and can also improve the power generation performance more effectively than when they are used separately.

Decoupling Control of Double-Side Frequency Tuning for LCC/S WPT System

The parameter fluctuations will lead to the frequency detuning problem of the wireless power transfer (WPT) system, thus affecting the transmission efficiency and output stability. The traditional primary-side frequency tuning method cannot realize the full compensation of the secondary-side resonance parameters, and the double-side frequency tuning method with data communication still exists a coupling problem. Therefore, this paper proposes a decoupling control of double-side frequency tuning for LCC/S wireless power transfer (LCC/S WPT) system, which has the advantages of avoiding information exchange and circuit simplicity. Firstly, based on the circuit model, the influence mechanism of frequency detuning on the transmission efficiency and voltage gain are deeply studied. On this basis, a zero phase angle (ZPA) control method based on optimal efficiency tracking and a two-step perturb and observe method with maximum current search are proposed to adjust the primary and secondary resonance parameters respectively. Finally, a 200W experimental prototype was built to verify the effectiveness of the proposed frequency tuning strategy. It is strong robustness to the parameter fluctuations, and double-side can well maintain the resonance state, which can improve the transmission efficiency and stability of the LCC/S WPT system.

VA Loading Optimization of a Converter Using the Rao Algorithm for Maximum Utilization of the Unified Power Quality Conditioner

In a modern power system, the unified power quality conditioner (UPQC) is considered to be the most effective device for mitigating power quality problems. The use of the dynamic voltage restorer (DVR) for active-reactive power-sharing reduces the loading on the UPQC in all operating conditions, leading to better system efficiency and reliability. The VA loading of the DVC can be controlled by maintaining a proper angle between load and source voltage. In this paper, Rao algorithms are proposed to determine the optimal VA loading of the UPQC using the variable phase angle control method. The primary objective of this study is to determine the optimum angle at which the VA loading of the UPQC is minimum without negotiating the compensation capabilities. To illustrate the effectiveness of the proposed methodology, the results are compared to those for JAYA optimization. This research work will help in the development of an efficient, instantaneous VA loading-based control approach for the UPQC.

New On-Line MTPA Angle Search and Control Methods Based on Digital Twins for IPM Synchronous Motor Drives Considering Motor Non-Linearity

New On-Line MTPA Angle Search and Control Methods Based on Digital Twins for IPM Synchronous Motor Drives Considering Motor Non-Linearity

Computer based speed control application for universal motor

In this study, speed control of alternative current (AC) universal motor is made in a computerized manner using PIC16F84A and PIC18F2550. AC universal motor speed control is realized by triggering the motor power circuit, triac with the phase angle control method by programming PIC16F84A. In the phase angle control method zero crossing points of AC line signal are detected by zero crossing detector and applied to the analog input of PIC16F84A. Zero crossing information applied to the microcontroller has provided phase control at a desired angle value in each alternance of the line. Motor speed control commands via computer are made by means of the control panel designed under Visual Basic 6.0 platform by using PIC18F2550 microcontroller based control card. Application results show that the speed control performed provides practical and easy control, is convenient, sensitive, and economic and also can immediately be adapted to different applications compared to the present analog control.

Analysis and Optimization Based on Factors Affecting the Spiral Climbing Locomotion of Snake-like Robot

The snake-like robot is a limbless bionic robot widely used in unstructured environments to perform tasks with substantial functional flexibility and environmental adaptability in complex environments. In this paper, the spiral climbing motion of a snake-like robot on the outer surface of a cylindrical object was studied based on the three-dimensional motion of a biological snake, and we carried out the analysis and optimization of the motion-influencing factors. First, the spiral climbing motion of the snake-like robot was implemented by the angle control method, and the target motion was studied and analyzed by combining numerical and environmental simulations. We integrated the influence of kinematics and dynamics factors on the spiral climbing motion. Based on this, we established a multi-objective optimization function that utilized the influence factors to optimize the joint module. In addition, through dynamics simulation analysis, the change of the general clamping force of the snake-like robot’s spiral climbing motion was transformed into the analysis of the contact force between the joint module and the cylinder. On the basis of the results, the effect of the control strategy adopted in this paper on the motion and change rule of the spiral climbing motion was analyzed. This paper presents the analysis of the spiral climbing motion, which is of great theoretical significance and engineering value for the realization of the three-dimensional motion of the snake-like robot.

Generation dispatch with large-scale photovoltaic systems

ABSTRACT The objective of this paper is to explore the role of generation dispatch strategy and spinning and non-spinning reserve methods in solving challenges posed by grid-connected large-scale PV systems as opposed to the commonly used approaches such as voltage, rotor angle and frequency control methods. The investigation covers the issues associated with the inherent intermittent of PV output, which results in additional operational challenges such as load-following requirements, spinning reserve requirements, load frequency excursions and system stability. A detailed performance evaluation of generation dispatch with large-scale PV systems is carried out in this research work based on the IEEE 14-bus test system using the MATLAB-based Power System Analysis Toolbox (PSAT). An analysis is conducted by using the power flow analysis methods such as power flow (PF), continuation power flow (CPF) and time domain (TD) analysis to gain an understanding of the influence that large-scale PV systems have on sub-transmission and transmission networks. The outputs of the study can be used to work out the appropriate penetration level of large-scale PV systems that can minimize their negative impacts on sub-transmission and transmission systems.

A novel hybrid control strategy of wind turbine wakes in tandem configuration to improve power production

The wind turbines that operate in the wake region of the upstream turbines produce less power and may suffer serious structural issues due to highly unsteady flows, which can reduce the life expectancy of the turbines. In this study, a novel hybrid wake control strategy for the wind farm power generation enhancement is proposed, which is based on highly accurate large eddy simulations coupled with the actuator line method. The combined effects of yaw angle and tilt angle control methods on the performance improvement of downstream wind turbines in wind farm layouts have not yet been investigated. This work would be the first attempt to evaluate the hybrid wake-control strategy of tandem wind turbines. It is found that the vortex generation is stronger at lower tilt angles because more parts of the rotor are affected by the wakes of the upstream wind turbine. An optimisation analysis is also provided to find the optimum wake deflection angles of the upstream turbine to maximize the electrical power generation. The results show that an accumulative power production increment of 17.1% is achieved by controlling both yaw angle (θ=30o), and tilt angle (φ=24o). The power obtained in the present study is approximately 6.1% higher than previous wake control techniques. By using the hybrid control strategy, an annual energy production enhancement of 3.7% is achieved, which is higher than the previous wake-controlled wind farm layouts.

A Group-Based Droop Control Strategy Considering Pitch Angle Protection to Deloaded Wind Farms

To promote the frequency stability of a system with high penetration of wind power integrated into it, this paper presents a systematic frequency regulation strategy for wind farms (WFs). As preparation for frequency response, a coordinated deloading control (CDC) scheme combining the over-speed control (OSC) and the pitch angle control (PAC) methods is proposed for wind turbine generators (WTGs) to preserve power reserve. The novelty lies in the consideration of high wind speed situations and pitch angle protection. Then, a group-based droop control (GBDC) scheme is proposed for a WF consisting of WTGs with the CDC. In this scheme, WTGs are divided into two groups for different controls. To improve the frequency response performance and ensure stable operation, the droop coefficients of the WF, groups, and all WTGs are determined according to their frequency regulation capabilities (FRCs). Moreover, pitch angle protection during the frequency response process is considered in this scheme. The effectiveness of the GBDC scheme is verified by comparing it with several existing droop control schemes in various situations.

Utilizing UPQC-DG to export reactive power to grid with power angle control method

Unified Power Quality Conditioner with Distributed Generation (UPQC-DG) is combined equipment that not only compensates power quality issues but also integrates distributed generation into the grid. This paper proposes to incorporate additional functionality in UPQC-DG to provide reactive power support to the grid. The proposed functionality enables the UPQC-DG to not only compensate for load reactive power but also to export it to the grid in a controllable and regulated manner. The control method of the proposed UPQC-DG system is based on a combination of Synchronous Reference Frame (SRF) theory and Unit Vector Template Generation (UVTG) and utilizes an additional PI controller to control the reactive power flow to the grid. Since the UPQC-DG in the proposed research handles an increased quantity of reactive power, the work incorporates the Power Angle Control (PAC) method to share reactive power burden between series and shunt Active Power Filters (APFs) of UPQC-DG for reducing the overall rating. The proposed UPQC-DG system is validated using exhaustive real-time simulations in Opal-RT for steady-state and dynamic performance.

Seamless Switching Technology of UPQC Based on Improved Power Angle Control

This paper presents a novel seamless switching technology between different operating conditions of the Unified Power Quality Conditioner (UPQC) with the energy storage system. Frequent start and stop of the series inverter will cause shock and loss under the conventional control method. Moreover, it is a key issue to achieve seamless switching when the UPQC operating condition changes. This paper proposes an improved power angle control (PAC) method to solve these problems. An agile power angle is calculated by this method under stable operating conditions. This feature enables the series inverter to share the load reactive power with the shunt inverter. On the other hand, both the series and shunt inverters are in an easy-to-switch operating state which can help achieve better seamless switching between different operating conditions. Simulation results show the shunt inverter capacity can be reduced up to 47% due to the reactive power sharing by both the inverters which means the reactive power burden of the shunt inverter is great lightened. It is also found that the switching time is about 300μs faster and the maximum voltage fluctuation amplitude is about 90V smaller under improved PAC than the conventional control method.

Wheel Deflection Control of Agricultural Vehicles with Four-Wheel Independent Omnidirectional Steering

Due to the harsh working environment of wheeled agricultural vehicles in the field, it is difficult to ensure that all wheels make contact with the ground at the same time, which is easy to unequally distribute the yaw moments of each independent wheel. The commonly used vehicle lateral control methods are mostly controlled by coordinating the individual torque between different wheels. Obviously, this control method is not suitable for agricultural four-wheeled vehicles. The goal of this study was to provide a wheel steering angle control method that uses electric push rods as actuators that can cope with this problem. The design of a four-wheel steering controller generally adopts the linear PID control method, but the research object of this paper is difficult to establish an accurate and linear mathematical model due to the complex working environment. Therefore, fuzzy adjustment is added on the basis of PID control, which can meet the requirements of model difficulty and control accuracy at the same time. In order to verify the feasibility and rationality of the designed wheel steering mechanism, the model dynamics simulation based on ADAMS software and the response analysis of the electric linear actuator thrust were completed. Based on the kinematics model of the controlled object, the rotation angle of the actuator motor is used as the control target, the lateral deviation e and deviation variation ec are taken as input variables and the parameters KP, KI and KD are taken as output variables, thereby establishing a fuzzy PID controller. Then, this controller is constructed in the Matlab/ Simulink simulation environment to analyze the lateral deviation and response stability during the process of vehicle path tracking. From the verification results of the linear path walking test under the fuzzy PID control method, the maximum lateral deviation of vehicle chassis is 2.7 cm when the driving speed is set as 1 m/s, and the deviation adjustment stable time of the system is 0.15 s. It can be seen that the proposed steering control strategy has good response performance and effectively increases the steering stability.

Smoothing the output power of a wind energy conversion system using a hybrid nonlinear pitch angle controller

Wind energy has been developed and is widely used as a clean and renewable form of energy. Among the existing variety of wind turbines, variable-speed variable-pitch wind turbines have become popular owing to their variable output power capability. In this study, a hybrid control strategy is proposed to implement pitch angle control. A new nonlinear hybrid control approach based on the Adaptive Neuro-Fuzzy Inference System and fuzzy logic control is proposed to regulate the pitch angle and maintain the captured mechanical energy at the rated value. In the controller, the reference value of the pitch angle is predicted by the Adaptive Neuro-Fuzzy Inference System according to the wind speed and the blade tip speed ratio. A proposed fuzzy logic controller provides feedback based on the captured power to modify the pitch angle in real time. The effectiveness of the proposed hybrid pitch angle control method was verified on a 5 MW offshore wind turbine under two different wind conditions using MATLAB/Simulink. The simulation results showed that fluctuations in rotor speed were dramatically mitigated, and the captured mechanical power was always near the rated value as compared with the performance when using the Adaptive Neuro-Fuzzy Inference System alone. The variation rate of power was 0.18% when the proposed controller was employed, whereas it was 2.93% when only an Adaptive Neuro-Fuzzy Inference System was used.

Implementation of Unified Power Quality Conditioner Based on Variable Phase Angle Control Method

This paper investigates the power quality problems which occur frequently in power supply and suggests a method to mitigate the power quality problems by the implementation of UPQC. P-Q problems generally concern with voltage sags/swells and harmonic currents. Custom Power (CP) devices that mitigate these power quality problems have gained more attention in the recent decades. UPQC is Designed, modelled and setup experimentally to mitigate voltage sag/swells and harmonic currents in three phase systems. UPQC consists of Dynamic Voltage Restorer (DVR) and Active Power Filter (APF). UPQC with proposed controller algorithms effectively compensates the sag/swell in supply voltage by keeping the load voltage amplitude at 0.9-1 per unit and eliminates the load current harmonics by keeping supply current at 5% less than of Total Harmonic Distortion,simultaneously. Keywords: Custom power device,Voltage sag,swell,Harmonics. DOI: 10.7176/ISDE/12-3-03 Publication date: September 30 th 2021

Quantitative analysis of total magnetic anomaly maps on archaeological sites—Part 1

In this study, which is the first part of quantitative analysis of total magnetic anomaly maps on archaeological sites, it is aimed to analyze the horizontal boundary values of potential buried structures that cause anomalies from the total magnetic anomaly maps of an archaeological excavation area. In the first step, the model was created in accordance with the archaeological structure. Noisy and noiseless anomaly maps of this model were calculated. These maps were enhanced using the reduction to pole and upward continuation methods. Tilt angle and automatic gain control methods were used. The responses of these methods on the total magnetic anomaly maps of the model were analyzed. In the second step, by applying the same procedures on the total magnetic anomaly map obtained from the magnetic measurements on the area that has not been excavated in the Amasya Oluz Mound archaeological excavation area, the horizontal boundaries of the potential structure elements of the region were analyzed.

Tracking moving mesoscale eddies with underwater gliders under autonomous prediction and control

A heading angle control method is proposed for controlling underwater gliders to follow a straight line sampling path relative to the center of a dynamically moving mesoscale eddy. The constant velocity and constant acceleration kinematic models are employed as motion models of eddy center movements. The model parameters are identified from historical data of eddy tracks. A Kalman filter is developed based on the models and real-time satellite imaging data to estimate and predict the movement of eddy centers. Performance of the two modeling approaches are compared based on historical data, results show that the constant velocity model is preferred for eddy movement prediction when used for glider heading control. Both simulation and field experiments confirm that underwater gliders under the heading control, when used with the Kalman filter, are able to follow the sampling path autonomously with acceptable level of tracking error.

Angle and Force Hybrid Control Method for Electrohydraulic Leveling System with Independent Metering

The electrohydraulic leveling system of the hydraulic press can realize automatic leveling control function. In order to eliminate the eccentric load force accurately, an electrohydraulic leveling system with independent metering is designed. Quasi-static behavior analysis of the leveling cylinders output forces performance is applied to the electrohydraulic leveling system with independent metering. The angle and force hybrid control method is proposed, and then the AMESim/Simulink cosimulation model is built. The HSIC controller and PID controller are used in the simulation, respectively. Simulation results show that both of the leveling angle control and leveling cylinders output forces control can be realized, simultaneously, and the HSIC controller has higher rapidity and smaller overshoot than the PID controller.

Автоматизований контроль механічних параметрів дводвигунового електропривода похилого дифузійного апарата

The article is devoted to the mechanical parameters automated control method development. Control object is the two-engine electric drive of an inclined diffusion apparatus. It is shown that in production conditions, the traditional automated control system, equipped with only electrical parameters control system, does not meet the requirements for the reliability of the two-engine electric drive with elastic bonds in the kinematic circuit. Structural schemes of two-motor electric drive`s relative rotation angle and speed control methods are developed. Theoretical evaluation of metrological characteristics of the proposed measuring channels was carried out, its static characteristics were constructed, and quantization errors were determined. It was established that the quantization error of the measuring channel is directly proportional to the mark number of engine shaft rotation sensors. Therefore, the optimal number of marks for means of mechanical parameters control was determined, which would ensure the necessary reliability of control. The algorithms of two-motor electric drive`s relative rotation angle and speed automated control are developed, the production implementation results of developed control means based on theoretical research are presented. Experimental studies of the two-motor electric drive`s relative rotation angle and speed automated control work, which showed the complete adequacy of measurement, both the speed of engines rotation and their shafts relative rotation angle, were carried out. The real metrological characteristics of these means correlate with theoretical developments. With the help of developed control means, experimental time charts were obtained that illustrate the operation of an inclined diffusion apparatus two-engine electric drive, in transient gear modes associated with the presence of an elastic-dissipative connection between the drive engines and the uneven distribution of torque between them. Preliminary theoretical studies of the dynamic properties of such an electric drive system have been experimentally confirmed.

Simplified Predictive Stator Current Phase Angle Control of Induction Motor With a Reference Manipulation Technique

Finite control set model predictive control (FCS-MPC) is a simple method and has an appropriate dynamic response for the drive applications. Applying additional control objects, e.g., the maximum torque per ampere (MTPA), is easy in FCS-MPC because of its characteristics. A direct application of FCS-MPC to MTPA is the predictive direct angle control method. Though this method eased the MTPA process, the good result is highly sensitive to the proper selection of the weighting factor. Furthermore, finding the best phase angle needs a complicated optimization process. In this paper, the application of simplified predictive control is proposed for angle control. By this proposed method, not only the weighting factor is eliminated but also the constraints of the motor are considered in the control strategy. In this way, the phase angle is automatically controlled in the proper value due to the torque while tedious computation is avoided. Therefore, the proposed method is valid in a wide range of operating points while no optimization process is performed due to changes in speed and torque. This proposed method is evaluated by simulations and experiments.