Robust position control of ultrasonic motor using VSS observer

Intrinsic properties of ultrasonic motor (high torque for low speed, high static torque, compact in size, etc.) offer great advantages for industrial applications. However, when load torque is applied, dead-zone occurs in control input. Therefore, sliding mode controller, which is a nonlinear controller, is adopted for ultrasonic motor. The state quantities, such as acceleration, speed, and position are needed to apply the sliding mode controller for position control. However, rotary encoder causes quantization errors in the speed information. This paper presents a robust position control method for ultrasonic motor by using Variable Structure System(VSS) observer. The state variables for sliding mode controller are estimated by the VSS observer. Besides, a small, low cost, and good response sliding mode controller is designed in this paper by using a micro computer that is essential in embedded system for the developments of industrial equipments. The effectiveness of the proposed method is verified by experimental results

Control of an Autonomous Hybrid Microgrid as Energy Source for a Small Rural Village

Nowadays, the exhaustion of electricity power in rural areas is becoming an important issue for many African Nations. Moreover, challenges include the high cost of extending the power grid to these locations, the economic health of the utilities and lack of revenue in impoverished villages. Numerous new initiatives are being implemented in the countries some of them co-financed by international organizations. In this paper, the hybrid microgrid is carried out as a feasible solution for a small rural village. A model of hybrid microgrid consisting of combination of photovoltaic (PV) panels and battery energy storage (BES) and a control system for managing the components of entire system to feed the village as local load is proposed. The control system must avoid the interruptions of power delivered to the consumers (village) and, therefore, good quality and reliability of system is required. The PI controllers are used to regulate the voltage and current using three-phase dq transformation, while the parameters are determined using Ziegler-Nichols tuning method. The effectiveness of the proposed method is verified by simulation results given by the Matlab/SimPowerSystems environment. 

Robust position control of ultrasonic motor considering dead-zone

Intrinsic properties of ultrasonic motor (high torque for low speed, high static torque, compact in size, etc.) offer great advantages for industrial applications. However, when load torque is applied, dead-zone occurs in the control input. Therefore, a nonlinear controller, which considers dead-zone, is adopted for ultrasonic motor. The state quantities, such as acceleration, speed, and position are needed to apply the nonlinear controller for position control. However, rotary encoder causes quantization errors in the speed information. This paper presents a robust position control method for ultrasonic motor considering dead-zone. The state variables for nonlinear controller are estimated by a Variable Structure System (VSS) observer. Besides, a small, low cost, and good response nonlinear controller is designed by using a micro computer that is essential in embedded system for the developments of industrial equipments. Effectiveness of the proposed method is verified by the experimental results

Multi-energy Microgrids Incorporating EV Integration : Optimal Design and Resilient Operation

There are numerous opportunities and challenges in integrating multiple energy sources, for example, electrical, heat, and electrified transportation. The operation of multi-energy sources needs to be coordinated and optimized to achieve maximum benefits and reliability. To address the electrical, thermal, and transportation electrification energy demands in a sustainable and environmentally friendly multi-energy microgrid, this paper presents a mixed integer linear optimization model that determines an optimized blend of energy sources (battery, combined heat and power units, thermal energy storage, gas boiler, and photovoltaic generators), size, and associated dispatch. The proposed energy management system seeks to minimize total annual expenses while simultaneously boosting system resilience during extended grid outages, based on an hourly electrical and thermal load profile. This approach has been tested in a hospital equipped with an EV charging station in Okinawa, Japan through several case studies. Following a M1/M2/c queuing model, the proposed grid-tied microgrid successfully integrates EVs into the system and assures continued and economic power supply even during grid failures in different weather conditions.©2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed

Multi-objective optimal operation with demand management and voltage stability

textabstractDue to the electric power liberalization, many power producers are entering into the deregulated power market. Most of the electrical power companies are introducing Renewable Energy Sources (RES), which will increase the power system uncertainty. Consequently, the underlyng uncertainty imposed by RES will increase the likelihood of voltage instability and voltage collapse. Also, fluctuations in supply and demand are increased by the introduction of renewable energies. On the other hand, Demand Response Program (DRP) is one of the potential solutions that reduces the power fluctuations. In this study, we proposed multi-objective optimal operation based Unit Commitment (UC) considering voltage stability and demand response. The effectiveness of the proposed method is verified by simulation results using the MATLAB

A control algorithm to increase the efficient operation of wind energy conversion systems under extreme wind conditions

This paper aims to increase the power production of gearless permanent magnet synchronous generator (PMSG) based wind energy conversion systems (WECS) in strong (greater than 25 m/s) wind speed regions. In general, most wind turbines cut off when wind speed is over the cut-out rate; as a result, the power generation of the wind farm decreases. This study introduces the look-up table pitch angle and rotational speed control to generate extra power in a strong wind region. Consequently, WECS can produce electric power at a reduced level until the wind speed reaches 35 m/s and the possibility of shutting down the wind turbines decreases. The proposed algorithm decreases the mechanical stress of wind turbine by decelerating rotational speed rather than turbine torque in strong wind regions. Furthermore, the model predictive control (MPC) is proposed to replace the PI controller in the inner current loop of the rotor speed control loop, thereby improving the performance of the stator current track. The proposed control method is validated in Matlab/SimPowerSystem software. The simulation result confirms that the proposed control method reduces the possibility of shutdown and guarantees temporally power production in strong wind conditions. 2022 The Author(s)This publication was made possible by Qatar University Collaborative Research grant [ QUCG-CENG-21/22-1 ] from the Qatar University. The statements made herein are solely the responsibility of the authors. The APC for this article is funded by the Qatar National Library, Doha, Qatar.Scopu

Strategija upravljanja pozicijom ultrazvučnog motora s putujućim valom

Since a conventional controller is continuous one, control period is normally set for a long time. When applying that controller for a travelling-wave ultrasonic motor whose parameters and performance are time-varying as a result of increasing temperature and operating condition, it is consequently resulted in degradation of the control performance. In this paper, a digital control algorithm is proposed for position control of the motors to shorten the long control period to maintain the stability of the motor performance. The proposed controller is digitally implemented by a SH7125 microcomputer utilizing a high-performance embedded workshop. The state quantities such as acceleration, speed and position, which are necessary for digital implementation, are provided by a rotary encoder. However, the optical encoder causes quantization errors in the speed information. To overcome the problem, a digital Variable Structure System (VSS) observer is also included to estimate the state quantities. The control input will be calculated after comparing the measured values and the estimated values given by the VSS observer. In short, a small, low cost and fast responsive digital controller is designed, based on a digital VSS observer, by using the SH7125 microcomputer. Effectiveness and reliability of the proposed digital controller are experimentally verified.Strategija upravljanja pozicijom ultrazvučnog motora s putujućim valom Sažetak: S obzirom da je standardni regulator najčešće kontinuirani, period upravljanja obično je postavljen na duži period. Koristeći takav regulator pri upravljanju ultrazvučnim motorom s putujućim valom, čiji su parametri i svojstva vremenski promjenjivi zbog povećanja temperature i promjena uvjeta rada, rezultat su smanjena upravljačka svojstva. U ovome radu predložen je digitalni upravljački algoritam za upravljanje pozicijom motora u svrhu smanjenja dugačkog perioda upravljanja za održavanje stabilnosti svojstava motora. Regulator je implementiran koristeći SH7125 mikroračunalo uz HEW (engl. high-performance embedded workshop) okruženje. Iznosi veličina kao što su akceleracija, brzina i pozicija, nužnih za digitalnu implementaciju, dobiveni su iz rotirajućeg enkodera. Međutim, optički enkoder dovodi do greške kvantizacije kod proračuna brzine. U svrhu smanjenja tog problema, u proces proračuna iznosa varijabli uključen je VSS (engl. Variable Structure System) estimator. Upravljački ulaz računa se nakon usporedbe mjerenih i estimiranih vrijednosti dobivenih korištenjem VSS-a. Dizajniran je digitalni regulator malih dimenzija, jeftine cijene i brzog odziva, temeljen na digitalnom VSS estimatoru koristeći SH7125 mikroračunalo. Eksperimentalno je provjerena efikasnost i pouzdanost digitalnog regulatora

Power System Planning and Quality Control

The optimum planning of the electrical power expansion and, accordingly, controlling the power quality are recent critical issues in power management [...