Functions of fuzzy logic-based controllers used in smart building
Authors : Ali M. Baniyounes, Yazeed Yasin Ghadi, Eyad Radwan, Khalid S. Al-Olimat
Abstract : The main aim of this study is to support design and development processes of advanced fuzzy-logic-based controller for smart buildings e.g., heating, ventilation and air conditioning, heating, ventilation, and air conditioning (HVAC) and indoor lighting control systems. Moreover, the proposed methodology can be used to assess systems energy and environmental performances, also compare energy usages of fuzzy control systems with the performances of conventional on/off and proportional integral derivative controller (PID). The main objective and purpose of using fuzzy-logic-based model and control is to precisely control indoor thermal comfort e.g., temperature, humidity, air quality, air velocity, thermal comfort, and energy balance. Moreover, this article present and highlight mathematical models of indoor temperature and humidity transfer matrix, uncertainties of users' comfort preference set-points and a fuzzy algorithm.
Keywords : Energy fifth keyword Fuzzy logic Indoor thermal comfort PID controller
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Grid-Connected PV System with Reactive Power Management and an Optimized SRF-PLL Using Genetic Algorithm
Authors :
Abstract : This paper presents a two-stage grid-connected PV system with reactive power management capability. The proposed model can send phase-shifted current to the grid during a low-voltage ride through (LVRT) to recover the voltage levels of the grid’s feeders. The novelty of the proposed algorithm, unlike the common methods, is that it does not need to disable the maximum power point tracking (MPPT) state while managing active and reactive power injection simultaneously. Moreover, the new method promotes a safety factor by offering overcurrent protection to the PV inverter. The phase-locked loop based on the synchronous reference frame (SRF-PLL) is optimized using a genetic algorithm (GA). The settling time of SRF-PLL’s step response is minimized, and the frequency dynamics are improved to enhance synchronization during LVRT. The system’s performance is tested and verified using MATLAB/Simulink simulations. The obtained results prove the effectiveness of the proposed control algorithm in managing reactive power interventions. The optimized phase-locked loop shows robust performance and is compared to the conventional low-gain PLL to spot the enhancement.
Keywords : grid-connected PV system; genetic algorithm; phase-locked loop; reactive power compensation
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Motor fault detection using sound signature and wavelet transform
Authors :
Abstract : The use of induction machines has gained fast popularity in many aspects of today’s energy applications and industrial productions. However, just as with any other machine, failure is expected due to a variety of faults in component and system levels. Therefore, it is necessary to improve machine reliability by performing preventive maintenance and exploring faulty indications in advance to avoid future failures. In normal operation, a distinct machine sound signature can be identify. Therefore, at any faulty operation, diagnosis of potential error can be defined based on output signature sound data analysis. Yet, this process of monitoring induction machine sounds and vibration can be hectic and extensive in terms of collecting data and compiling analysis. That is, a huge number of data samples need to be collected and stored in order to define abnormality operation. Therefore, in this work, wavelet-based algorithms were developed as an analysis process to analyze collected data and identify abnormality, with much fewer data samples and compiling process, as special prosperity of wavelet transform. As a result, MATLAB codes were implemented to analyze data based on sound signature technique and wavelet transform algorithms to show a significant improvement in identifying potential error and abnormality conditions.
Keywords : condition monitoring; discrete wavelet transform; fault diagnosis; induction motor; sound analysis
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Energy Conservation as a Sustainable Strategy for Smart Home Buildings in Amman, Jordan with Improving Indoor Built Environment features and key performance
Authors :
Abstract : As an ingenious efficient environment, smart buildings can be considered as essential constituents for energy conservation. That is, in today's energy demands upsurges and energy sources degradation, the idea of the smart home building has a major implication on improving the living environment along with cutting down on energy consumptions. Therefore, this study investigates the energy conservation theme in Amman, Jordan in terms of opportunities and challenges vs. renewable energy technology. This study was based on interviews with the expert (academics, professionals architects, and electrical engineers, in addition to employees in Electrical companies) aiming to identify the problematic gap in designing theoretical analysis of a smart automated building based on collaboration work between Electrical and Architectural Engineering. From an Electrical Engineering point of view, automated control building systems can provide efficient means of comfort, sustainable habitat environment, and energy conservation as a building advantage. Such a scheme can be accomplished through automated control software (LabView), sensors, network infrastructure, logic design, and mechanical actuators. Meanwhile, from an architecture point of view, passive design strategies can reduce energy consumption along with public awareness for building users. This was implemented through simulation for base case building showing the integration between architectural and electrical systems through using a hybrid system. As a result, this new building automation design will help reducing energy consumption by controlling light fixtures, air-condition, water pumps, and many more appliances. The design guidelines, once formulated and enacted, will guarantee energy conservation qualitatively which will serve as a proposed guideline for enhancing buildings' regulation and codes
Keywords : Energy Conservation, Sustainable Strategy, Smart Building, Indoor Built Environment
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Design of type-1 servo controller for grid voltage modulated direct-power control of single-phase grid-connected PV inverter
Authors :
Abstract : This paper presents direct control of active and reactive power using grid voltage modulation for single-phase grid-connected photovoltaic inverter. A design of type-1 servo system based on pole-placement method is proposed to control the power flow using a simplified multiple-input multiple-output (MIMO) model of the system. Phase-locked loop (PLL) with a quarter cycle time delay is used to estimate the grid phase angle for the purpose of performing the stationary and synchronous reference frame transformation. Unipolar pulse width modulation (PWM) technique is used to control a single-phase inverter with 2.7 KVA capacity connected to the photovoltaic system. The proposed controller can simply be tuned using minimum number of controller gains to achieve the transient and steady-state performance requirements. The proposed system, was capable of operating for a wide range of solar irradiance levels with a power factor in the range of 0.95 (leading/lagging), for the reactive power compensation purposes.
Keywords : decoupled control; direct power control; grid-connected; renewable energy; single-phase inverter
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Direct control of active and reactive power for a grid-connected single-phase photovoltaic inverter Maximum power tracking Photovoltaic array Reactive power Renewable energy Single-phase inverter
Authors :
Abstract : This paper presents a single-phase grid-connected photovoltaic system with direct control of active and reactive power through a power management system of a Photovoltaic inverter. The proposed control algorithm is designed to allow maximum utilization of the inverter's available KVA capacity while maintaining grid power factor and current total harmonic distortion (THD) requirements within the grid standards. To reduce the complexity and improve the efficiency of the system, two independent PI controllers are implemented to control single-phase unipolar PWM voltage source inverter. One controller is used to control the power angle, and hence the active power flow, while the other controller is used to control the reactive power, and consequently the power factor by adjusting the voltage modulation index of the inverter. The proposed system is modelled and simulated using MATLAB/Simulink. The PV inverter has been examined while being simultaneously connected to grid and local load. Results obtained showed the ability of the PV inverter to manage the active and reactive power flow at, and below rated levels of solar irradiances; resulting in an increased inverter utilization factor, and enhanced power quality. The proposed system was capable of operating at power factors in the range of 0.9 lead or lag for reactive power compensation purposes and delivered its power at a wide range of solar irradiance variations.
Keywords : Distributed generation, Grid-connected, Maximum power tracking, Photovoltaic array, Reactive power, Renewable energy, Single-phase inverter
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Toward Developing Energy Star Rating Development in Jordan
Authors :
Abstract : The objective of this article is to provide an efficient means of enforcing green building in Jordan, the Middle East. The paper is proposing assessment tool of Energy Star Rating Scheme and also explaining its role for achieving sustainable development during buildings lifecycle and hence reducing energy and water usage. The Scheme development will remove considerable environmental, social and economic issues as Jordan is a country that renowned for its poor energy and water resources. The article provides technical aspects, means, technologies and processes for proposing and implementation Green star ratings for buildings. The star ratings are based on integrating renewable energy technologies, water recourses and its consumption management and waste recycling and its management throughout the buildings’ life cycle including its design, installation and operation.
Keywords : Energy star ratings, Energy and water, Sustainable energy, Environment
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Harmonic Analysis of Photovoltaic Generation in Distribution Network and Design of Adaptive Filter
Authors :
Abstract : The aim of this paper is to investigate the effect of increased penetration level of Photovoltaic (PV) generation on the distribution network. Harmonic distortion is the main factor studied in this paper and a typical three-bus distribution network is built in MATLAB/Simulink to understand the harmonics problem. The obtained results show that current harmonics are more susceptible to fluctuate compared to voltage harmonics. Based on existing IEEE harmonic standards, total demand distortion of current (TDDi) is evaluated to estimate maximum PV penetration level at Point of Common Coupling (PCC), and the maximum acceptable TDDi at each bus differs according to specific loading and short-circuit levels. Meanwhile, total harmonic distortion of current (THDi) at inverter outputs represents inverter performance. Instead of assessing at standard test conditions (STC), the impact of irradiance variations is studied. Low irradiance results in an increased THDi of the inverter whilst doesn't explicitly affect TDDi at PCC. A simple and low-cost solution is proposed to dynamically vary the settings of inverter's filter elements against irradiance, and harmonic distortion at low irradiance of the inverter is successfully mitigated.
Keywords : total harmonic distortion, total demand distortion, irradiance, PV penetration level, power system
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Fuzzy logic control for low-voltage ride-through single-phase grid-connected pv inverter
Authors :
Abstract : This paper presents a control scheme for a photovoltaic (PV) system that uses a single-phase grid-connected inverter with low-voltage ride-through (LVRT) capability. In this scheme, two PI regulators are used to adjust the power angle and voltage modulation index of the inverter; therefore, controlling the inverter’s active and reactive output power, respectively. A fuzzy logic controller (FLC) is also implemented to manage the inverter’s operation during the LVRT operation. The FLC adjusts (or de-rates) the inverter’s reference active and reactive power commands based on the grid voltage sag and the power available from the PV system. Therefore, the inverter operation has been divided into two modes: (i) Maximum power point tracking (MPPT) during the normal operating conditions of the grid, and (ii) LVRT support when the grid is operating under faulty conditions. In the LVRT mode, the de-rating of the inverter active output power allows for injection of some reactive power, hence providing voltage support to the grid and enhancing the utilization factor of the inverter’s capacity. The proposed system was modelled and simulated using MATLAB Simulink. The simulation results showed good system performance in response to changes in reference power command, and in adjusting the amount of active and reactive power injected into the grid.
Keywords : grid-connected inverter; fuzzy logic control; low-voltage ride-through; photovoltaic system
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Modified phase locked loop for grid connected single phase inverter
Authors :
Abstract : Connecting a single-phase or three-phase inverter to the grid in distributed generation applications requires synchronization with the grid. Synchronization of an inverter-connected distributed generation units in its basic form necessitates accurate information about the frequency and phase angle of the utility grid. Phase Locked Loop (PLL) circuit is usually used for the purpose of synchronization. However, deviation in the grid frequency from nominal value will cause errors in the PLL estimated outputs, and that's a major drawback. Moreover, if the grid is heavily distorted with low order harmonics the estimation of the grid phase angle deteriorates resulting in higher oscillations (errors) appearing in the synchronization voltage signals. This paper proposes a modified time delay PLL (MTDPLL) technique that continuously updates a variable time delay unit to keep track of the variation in the grid frequency. The MTDPLL is implemented along a Multi-Harmonic Decoupling Cell (MHDC) to overcome the effects of distortion caused by gird lower order harmonics. The performance of the proposed MTDPLL is verified by simulation and compared in terms of performance and accuracy with recent PLL techniques.
Keywords : multi-harmonic decoupling; phase locked loop; variable time delay adjustment
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Wavelet estimation of THD based on Hilbert transform extraction
Authors :
Abstract : In evaluating the quality of waveform energy, Total Harmonic Distortion can be one of the unique testing parameters showing the disturbance effect on pure waveform or regenerated waveform. As harmonics may added to distort the fundamental waveform, the analysis of signal dynamic characteristic and the measurement of harmonics effect on the integrity of the waveform will be study to explore and enhance the testing process. In previous work, Fourier Transform and Wavelet Transform algorithms were employed to analyze characteristics of a waveform. In this work, Hilbert Transform in pairs with Wavelet Transform algorithms, that draw a lot of researchers attention, will be investigated as new propose testing technique to identify signal distortion with the effect on the waveform energy and fundamental frequency. This new proposed testing technique will be validated with conventional methods in terms of accuracy, number of collected data samples, and complexity of data compiling.
Keywords : Total Harmonic Distortion, Analog to Digital Converters, Hilbert Transform, Wavelet Transform
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SENSORLESS SPEED AND POSITION CONTROL OF PERMANENT MAGNET SYNCHRONOUS MOTORS USING HYBRID HIGH FREQUENCY SIGNAL INJECTION METHOD
Authors :
Abstract : Sensorless control of permanent magnet synchronous motor (PMSM) requires the absolute position information to be estimated from the motor currents and voltages. Conventional model-based estimation algorithm is effective at medium and high-speed operation but performs poorly at low and zero speed operation due to small value of motor currents and voltages which then leads to low SNR values. This paper presents a hybrid rotor position estimation algorithm over a wide speed range. At low speed, a new compensated high frequency signal injection method which utilizes Kalman filtering is proposed to estimate the rotor position at zero and low speeds. At high speed applications, a direct scaling method which utilizes the machine model is proposed. The two methods are combined by a reasoning simple algorithm to estimate the rotor speed over the entire speed range. The performance of the proposed estimation method is tested via simulation using Maltlab and Simulink. The results obtained showed the effectiveness and efficiency of the proposed methods over a wide speed range with and without load.
Keywords : sensorless control, permanent magnet synchronous motor, frequency injection
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Improvements on the High Frequency Signal Injection Method for Permanent Magnet Synchronous Motors and its Application in the Hybrid Drive Position Control
Authors :
Abstract : This paper presents a hybrid rotor position estimation for permanent magnet synchronous motor (PMSM) over wide speed range. At zero and low speeds, a rotor position error compensation scheme is proposed to improve the performance of high frequency signal injection method. This includes the incorporation of system modeling and Kalman filtering to improve the estimation performance during transient. At medium and high speeds, a novel yet simple approach called direct scaling is presented to estimate the rotor position. The two methods are combined in a hybrid scheme and implemented for position control of PMSM drive. Simulation results demonstrate the improvements in the high frequency signal injection method during steady state and transient conditions. The performance of the hybrid sensorless motor drive for wide speed range is also tested via simulations. The obtained results show the effectiveness of the proposed methods over the entire speed range.
Keywords : Frequency, Permanent magnet motors, Position control, Rotors, Error compensation, Modeling, Kalman filters, Magnetic separation, Filtering, Steady state
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ADAPTIVE FUZZY PI SPEED CONTROLLER GAINS FOR PERMANENT MAGNET SYNCHRONOUS MOTOR
Authors :
Abstract : The conventional proportional integral (PI) and proportional integral derivative (PID) controllers have been widely utilised as speed controllers in PMSM drives. However, the conventional fixed-gain PI and PID controllers are very sensitive to step change of command speed, parameter variations and load disturbance. To overcome the drawbacks of the fixed gains PI controller, an adaptive fuzzy logic controller is presented in this paper to tune the PI controller gains online. The proposed adaptive fuzzy logic controller processes the speed error and adjusts the PI controller gains automatically to achieve the desired response under different operating conditions. The fuzzy rule base is designed and optimised to achieve the desired control response such as rise time, overshoot and steady state error. The performance of the proposed controller is examined, by simulation using Simulink/Matlab at different operating conditions. The operating conditions studied included various step speed commands from standstill with nominal and changes in motor parameters and load torque. The results obtained were evaluated and compared with the fixed-gains PI controller. The simulation results showed the superiority of the adaptive controller over the conventional fixed-gain PI controller especially for load disturbances and load inertia variations.
Keywords : PID controllers, adaptive fuzzy, permanent magnet synchronous motor, speed controller
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IRFOC induction motor with rotor time constant estimation modelling and simulation
Authors :
Abstract : The authors provide a new and simple inverse rotor time constant identification method which can be used to update an indirect rotor field oriented controlled (IRFOC) induction motor algorithm. Two different equations are used to estimate the rotor flux in the stator reference frame. One of the equations is a function of the rotor time constant, rotor angular velocity and the stator currents. The other equation is a function of measured stator currents and voltages. The equation that uses the voltage and the current signals of the stator serves as reference model, however, the other equation works as an adjustable model with respect to the variation of the rotor time constant. Voltage signals used in the reference model equation are obtained from the measured DC bus voltage and the inverter gating signals. The proposed scheme is verified using a MATLAB/SIMULINK model for two different motors and experimentally using a DSP development tool (MCK 243) supplied by Technosoft S.A. The proposed estimator was able to successfully track the actual value of the inverse rotor time constant for different load torque and speed operating conditions. Increased oscillations in the estimated inverse rotor time constant appeared at lower speeds (below 10 per cent of rated speed) due to drift in a PI regulator (used at the estimator side), which was tuned under rated operating conditions and using parameters nominal values. This estimation scheme is limited when near zero speed operation is demanded; otherwise it gives a simple and practical solution. A suggested way out of this, is to provide a self-tuning controller that can automatically adjust even for zero speed operation, or to automatically disconnect the estimator and take the most updated value as long as the operating speed is below a predetermined value.
Keywords : IRFOC induction motor, rotor time constant, modelling and simulation, PI controller
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