Apinan Aurasopon

Power Factor Improvement and Voltage Harmonics Reduction in Pulse Width Modulation AC Chopper Using Bee Colony Optimization

Abstract This paper presents a new pulse width modulation (PWM) switching technique for a single phase AC chopper. In the proposed technique, the switching frequency is fixed and the optimal PWM switching angles are obtained by using bee colony optimization. This process can improve the input power factor and reduce the total harmonic distortion of the output voltage. The performance of the proposed technique is compared with that of the conventional PWM through the simulation and experimental results.

Asymmetrical PWM for Harmonics Reduction and Power Factor Improvement in PWM AC Choppers Using Bee Colony Optimization

This paper presents the application of bee colony optimization (BCO) to obtain the optimal switching angles for single phase PWM AC choppers. The optimal switching angles are found in the region of 0-π based on the asymmetrical PWM technique. This PWM process results in improvements of the total harmonic distortion of the output voltage and in the input power factor. Simulation and experimental results are compared with the conventional PWM to verify the performance of the proposed PWM process.

Optimal Switching Pattern for PWM AC-AC Converters Using Bee Colony Optimization

This paper proposes a harmonic reduction approach for a pulse width modulation (PWM) AC-AC converters using Bee Colony Optimization (BCO). The optimal switching angles are provided by BCO to minimize harmonic distortions. The sequences of the PWM switching angles are considered as a technical constraint. In this paper, simulation results from various optimization techniques including BCO, Genetic Algorithm (GA), and Particle Swarm Optimization (PSO) are compared. The test results indicate that BCO can provide a better solution than the others in terms of power quality and power factor improvement. Lastly, experiments on a 200W AC-AC converter confirm the performance of the proposed switching pattern in reducing harmonic distortions of the output waveform.

Designing parameters in PWM buck AC chopper for unity input power factor

This paper presents the technique for selecting the parameters based on PWM buck AC chopper. This results the optimal capacitor filter that produces the phase angle of input current in phase with that of input voltage. Therefore, the converter operates at unity input power factor. The simulation results by Pspice program are used to verify the proposed technique.

Classification of the cattle's behaviors by using accelerometer data with simple behavioral technique

To prognosticate the cattles health, the farmer can observe the cattle activities such as the time period of walking-grazing, standing and sleeping. However, to monitor the cattles behaviors, it is unable to monitor such behavior all the time and thorough, especially raise many cattle. Therefore, this paper proposes to classify the cattles behaviors by using the magnitude and standard deviation of accelerometer output signal. The magnitude of each axis is used to classify the behaviors into two groups: 1) walking-grazing and standing and 2) lying down. While the standard deviation of Y-axis is used to notify the behaviors of walking-grazing and standing. The classification results were tested with two cattle and measured precise time of each behavior comparing with human observers. As a result, duration of each behavior is nearby, it has the errors as follows walking-grazing maximum errors 2% standing maximum errors 13% and lying maximum errors 7%.

Classification system for estrus behavior of cow using an accelerometer

Generally, estrus of cow can be observed from its body such as swollen vagina, slime and mydriasis or its behaviors such as bellow out, ride piggyback with the other or let the other rides piggyback. These symptoms will only occur within 18 hours. To access the best result, therefore, the insemination should be processed during on 9-18 hours of that period time. Therefore, this project proposes the application of accelerometer for checking estrus of cow. The accelerometer is installed on the cows front leg. When the cow rides piggyback the other, resulting the output signal of accelerometer is changed. This signal will be sent to the microcontroller for processing and send the signal through wireless to computer for displaying. The proposed system will be useful to improve efficiency of the insemination.