Current Issue : October-December Volume : 2024 Issue Number : 4 Articles : 5 Articles
The rising popularity of grid-connected multilevel inverters with photovoltaic panels underscores the importance of effective modulation and control strategies for ensuring optimal power quality. The performance of these inverters hinges significantly on modulation and control approaches, specifically addressing issues like common mode voltage, harmonics, switching loss, and dynamic response. This study introduces a novel approach to mitigate current harmonics in these inverters by employing sliding mode control. Notably, this technique achieves harmonic reduction without necessitating an increase in the switching count. The presented technique eliminates phase-locked loop, current controllers, and carrier waves, thereby easing hardware computation. Beyond computational efficiency, this approach contributes to enhanced power quality and dynamic response within the inverter system. Simulation results affirm the efficacy of the proposed method when compared to the use of the phase opposite disposition modulation combined with the current controllers. In the nominal operational mode, the proposed method reduces the current Total Harmonic Distortion (THD), the highest magnitude of individual harmonics, and the switching count by 43.6%, 73.5%, and 19.6% respectively, compared with those of the method using the phase opposite disposition modulation combined with current controllers....
Global warming and energy-saving efforts make it necessary to look for energy-free technology to reduce buildings’ temperature. This work aims to develop a system for monitoring green panels’ physical variables (atmospheric temperature, humidity, soil humidity, amount of light, and vibration) to determine their efficiency. A model of a green panel was outfitted with detectors that recorded atmospheric variable modifications within and outside the green panel under evaluation. Open-source code and hardware were used to record all variables and store the data. Once the monitoring system is completed, a green panel model is developed as concept proof for monitoring the physical variables; a database is created, studied, and tested using the formulated hypothesis. The variables were analyzed using current techniques of statistical description, and the results obtained support the idea underpinning the feasibility of implementing green panels in city houses and buildings. A substantial difference in temperature up to 12°C was found when using green walls and ceiling systems at the hottest times of the day. The humidity in the air is up to 88%, generating an atmosphere of comfort in buildings where these systems are installed....
This research paper investigates an LED strip lighting system, whose LED lighting controller was developed based on the PIC24FV32KA302 microcontroller and PCA9685 PWM driver. During the study, various parameters of the system were evaluated, including the response time from the length of commands, the dependence of the PWM signal characteristics on the logic values generated by the microcontroller, and the dependence of the LED light flux and power on the percentage of the PWM signal and the power of the power supply channels. The results of the study revealed that the reaction time depended on the length of the sent command, where as the logic values of the microcontroller were changed from 1000 to 4000, the size of the PWM signal changed from 25 to 100%. The use of the I2C communication protocol, which is a master–slave architecture and uses data and synchronization lines, was also found to affect response times. When the percentage of the PWM signal was changed from 10 to 100%, the light flux of the LED strip changed from 100 to 1000 lm. These results reflect the advantages of applying microcontrollers and PWM drivers to LED control systems, emphasizing their flexibility, efficiency, and precise light control....
To solve the problem of optical path difference velocity (OPDV) stability in the Fourier spectrometer, a Cerebellar Model Articulation Controller-Proportional-Integral-Derivative (CMAC-PID) composite control strategy is proposed. The relationship between the angular velocity of the rotary-type voice coil motor (RT-VCM) and the OPDV was studied, along with a mathematical model of the parallel rotating mirror interferometer system. CMAC-PID is designed and simulated on this basis to suppress the disturbance of nonlinear factors in the system model. The simulation results demonstrate that the steady-state fluctuation error of the CMAC-PID controller is 90.1% less than that of the PID controller. The experimental results indicate that compared to the PID controller, the CMAC-PID controller improves the stability of the OPDV by 1.25%, which means that time-varying disturbances are effectively suppressed....
The four-wheel steering distributed drive vehicle is a novel type of vehicle with independent control over the four-wheel angle and wheel torque. A method for jointly controlling the distribution of the wheel angle and torque is proposed based on this characteristic. Firstly, the two-degrees- of-freedom model and ideal reference model of four-wheel steering vehicle are established; then, the four-wheel steering controller and torque distribution controller are designed. The rear wheel angle is controlled by the feedforward controller and the feedback controller. The feedforward controller takes the side slip angle of the center of mass as the control target, and the feedback controller takes the yaw angle as the control target. Torque is controlled by two control layers, the additional yaw moment of the upper layer is calculated by the vehicle motion state and fuzzy control theory, and the lower layer distributes wheel torque through the road adhesion coefficient and wheel load. Finally, a simulation platform is established to verify the effectiveness of the proposed control algorithm....
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