Design and Implementation of Z-Source Inverter by Simple Boost Control Technique for Laboratory Scale Micro-Hydro Power Plant Application

In a power plant such as micro-hydropower (MHP), an induction generator (IG) is usually employed to produce electrical power. Therefore, an inverter is needed to deliver it with high efficiency. Z-source inverter (ZSI) has been introduced as a topology with many advantages over conventional inverters. This research aims to investigate the performance of ZSI based simple boost control (SBC) in laboratory-scale MHP systems using a rewinding induction generator. This research has been conducted both from simulations and experiments. Based on the result, the waveform characteristic and value of ZSI are close to the desired design. A shoot-through duty ratio of 17% can reach 60 Vrms output voltage, and this condition has a conversion ratio of about 2.05 times. Also, SBC can significantly reduce the Total Harmonic Distortion (THD). ZSI efficiency has a value of 84.78% at 50% of rating load 100 W and an average value of 80%. Compared to the previous study, the proposed design has more economical with the same component for the higher rating power. Moreover, it has a smoother and entire output waveform of the voltage.

Relay-Based Clustering Method for Interference Management in Heterogeneous Wireless Cellular Network

Femtocell is one of solutions to improve quality of services and network capacity for users in indoor areas. Radio resources used by femtocells are shared from macrocell network, thus it saves the use of frequency spectrum. However, one of problems in deploying femtocells within coverage area of macrocells is interference due to radio resources sharing between femtocells and macrocells. It creates interferences called as cross-tier (macrocell-femtocell/femtocell-macrocell) and co-tier (macrocell-macrocell/femtocell-femtocell) interferences. This paper proposes a relay-based clustering method to mitigate interference in femtocells located in the whole edge area of macrocell and the cell edge area of sectorized macrocells. Relay nodes are deployed statically (fixed location) in the neighboring macrocell area. Relay node will recruit their members based on the shortest distance. Certain relay node’s members do not need to transmit large amounts of power to enhanced Node B (eNB), such that interference from Macrocell User Equipment (MUE) to Home enhanced Node B (HeNB) can be minimized. Simulation experiments has been carried out and optimistic results for the sectorized macrocells scenario show that Signal-to-Interference-plus-Noise-Ratio (SINR) of femtocells for the conventional system that does not reach the targeted SINR of 20 dB is 87%. Meanwhile, after applying the relay-based clustering method, SINR value of femtocells below or equal to 20 dB reaches 72%. Optimistic results for throughput and Bit Error Rate (BER) show improvement of 15% and 14%, respectively. It has been shown that the relay-based clustering method can provide better performance compared to the conventional system even for femtocells densely deployed.

Rompi Penyedia Informasi bagi Penyandang Tunanetra Menggunakan Multisensor HC-SR04

Various electronic travel aids for people having visual impairment have been developed based on ultrasonic object detection employing the HC-SR04 ultrasonic proximity sensor. However, most of them do not consider blind spots where harmful objects cannot be detected. This study discusses the development of a vest that can detect objects in front of the blinds more widely and provide sound alert if an object in front is detected. This detector was developed based on an Arduino Uno equipped with five HC-SR04 ultrasonic sensors, and a mini DFPlayer module. In addition, blind area analysis of sensor detection is carried out to overcome objects that are not detected by similar studies. Horizontally, this travel vest sweeps objects up to 150 cm in distance with a 25o right or left angle deviation from forward direction. Vertically, object detection reaches up to 150 cm in distance with both upward and downward deviation of 30o from the vest.

Analisis Kinerja Metode Fuzzy Teroptimasi PSO untuk Strategi Kendali MPPT pada Sistem Solar Photovoltaic

A fuzzy control system has been widely used in various problem solving. Its performance can be optimized using particle swarm optimization (PSO). This performance can be proven by applying it to the maximum power point tracking (MPPT) control strategy on solar photovoltaic systems. Solar photovoltaic power generation systems are increasingly popular because they are clean and renewable energy sources. The power generated by solar photovoltaic is strongly influenced by solar irradiation and the load carried. In order to obtain maximum power output, an MPPT control strategy is needed. An MPPT control strategy based on fuzzy and PSO hybrid control systems is proposed in this research. The fuzzy-PSO method selects and produces the optimal duty cycle for the boost dc-dc converter in a solar photovoltaic system. Variable duty cycle due to solar irradiation and load changes can be conditioned by the fuzzy-PSO-based MPPT method to extract maximum power. The research results show that the fuzzy-PSO method can control the solar photovoltaic output voltage through a dc-dc converter to produce maximum power at various solar irradiations. Test result by applying a resistive load produces output power at the maximum point. The best result is obtained in the 100 Ohm load test: the response time of 0.0818 seconds and excellent robustness.

Optimized Hybrid DCT-SVD Computation over Extremely Large Images

High performance computing (HPC) is required for image processing especially for picture element (pixel) with huge size. To avoid dependence to HPC equipment which is very expensive to be provided, the soft approach has been performed in this work. Actually, both hard and soft methods offer similar goal which are to reach time computation as short as possible. The discrete cosine transformation (DCT) and singular values decomposition (SVD) are conventionally performed to original image by consider it as a single matrix. This will result in computational burden for images with huge pixel. To overcome this problem, the second order matrix has been performed as block matrix to be applied on the original image which delivers the DCT-SVD hybrid formula. Hybrid here means the only required parameter shown in formula is intensity of the original pixel as the DCT and SVD formula has been merged in derivation. Result shows that when using Lena as original image, time computation of the singular values using the hybrid formula is almost two seconds faster than the conventional. Instead of pushing hard to provide the equipment, it is possible to overcome computational problem due to the size simply by using the proposed formula.

Implementasi Realitas Berimbuh pada Antarmuka Manusia-Mesin di Industri Proses

Process industries such as oil refineries, petrochemical plants, and power plants require a human-machine interface system to monitor continuously. The operator usually carries out monitoring via a human-machine interface. However, it is difficult to know the condition of process equipment in real-time. The implementation of augmented reality allows engineers to visualize process equipment in real-time when conducting field inspections. The implementation of augmented reality at the human-machine interface to the fluid catalytic cracking process in an oil refinery is discussed in this paper. The design was started by developing a three-dimensional process equipment model using Autodesk Inventor. The result of the three-dimensional model then using Unity 3D software connected to the Vuforia Engine was implemented on a gadget into an augmented reality application. Data communication performance analysis was carried out using inferential statistics methods to test variations in service quality at levels 0, 1, and 2. The result of the Tukey test showed that the communication network latency value in level 2 was significantly higher than levels 0 and 1, which was 0.704±0.108 seconds. These results indicate that augmented reality can be implemented on human-machine interfaces by ensuring the quality of data communication services using Message Queue Telemetry Transport (MQTT) protocol at levels 0 or 1.

Implementasi Kendali Keseimbangan Gerak Two Wheels Self Balancing Robot Menggunakan Fuzzy Logic

Self balancing robot is a two-wheeled robot that only has two fulcrums so that this robot is an unbalanced system. Therefore, a control system that can maintain the stability of the robot is needed so that the robot can keep in standing position. This study aims to design a self-balancing robot and its control system which improves the robot's performance against the maximum angle of disturbance that can be overcome. The control system used is based on fuzzy logic with 9 membership functions and 81 rules. The control system is applied to the ESP-32 microcontroller with the MPU-6050 sensor as a feedback position of the robot and DC motor as an actuator. Complementary filters are added to the MPU-6050 sensor readings to reduce noise to obtain better robotic tilt angle readings. The improvement of this research compared to previous research based on fuzzy is the addition of the number of membership functions from 7 to 9 and the embedding of a complementary filter on the MPU-6050 sensor output reading. The result shows that the designed self balancing robot which has dimensions of 10cm x 18cm x 14.5cm can cope with the maximum disturbance angle up to 17.5⁰.

Watermarking berbasis Redundant Discrete Wavelet Transform dan Arnold Transform pada Citra Medis

In telemedicine, data transmission in digital medical images and electronic medical records through the internet is vulnerable to various threats of theft and manipulation. Image watermarking is needed to provide authentication and security to medical images. This paper proposes an image watermarking scheme based on Redundant Discrete Wavelet Transform (RDWT) and Discrete Cosine Transform (DCT) with watermark encryption using Arnold transform. First, the original host medical image was decomposed into four subbands using RDWT. Then, DCT is applied to the LH subband of the RDWT. On the other hand, the watermark is scrambled using Arnold transform to ensure identity security. The singular value of the watermarked image is obtained by modifying the singular value of the host image and the watermark. Tests were carried out on different medical images, namely X-ray, MRI, CT, and ultrasound, with a watermark in a proprietary logo. The host medical image is the same size as the watermark image. The result of this study can provide high authentication, imperceptibility and security in medical images, with an average PSNR value of 65.67 dB, SSIM 1, BER 0, NC 1. This scheme is resistant to JPEG compression, noise addition, filtering, image sharpening, image enhancement, geometric operations, motion blur, image sharpening, and histogram equalization.

Otomatisasi Sistem Fertigasi Tetes untuk Tanaman Berbasis Mikrokontroler

The process of manual fertilization and irrigation of plants has disadvantages such as it requires human labor and is inefficient in the use of fertilizers and water sources. Therefore, the purpose of this research is to design and develop an automatic fertigation system. The method used in this research is a drip fertigation technique where the fertigation liquid that has been stirred is placed in a tank with 100 cm height from ground. With the gravitational force, the fertigation liquid is distributed through pipes, hoses and emitters around the plant. While the control system and automation of fertigation distribution to plants is carried out based on a microcontroller that need the condition of soil moisture values around the plant. If the watering time and humidity values are met, the electronic valve will open so that the fertigation liquid flows from the tank to the plants. Furthermore, in this study the tests were carried out to determine the uniformity coefficient and debit of drip fertigation. From the results, it shows that the emitter’s debit influenced by the liquid level in the tank. The uniformity coefficient obtained in the two tests is greater than 90%. From the two tests carried out from the moisture sensor 1 and 2, it shows the mean percentage error for both sensor is less than 1.7%, while the percentage error of soil moisture sensor 1 is 1.6% and the percentage error of soil moisture sensor 2 is 1%, respectively. Meanwhile, from the ultrasonic sensor testing it was obtained 0% of error. It also shows from the testing conducted that the fertigation system works very well and successfully.

Strategi Pengisian Baterai pada Sistem Panel Surya Standalone Berbasis Kontrol PI Multi-Loop

This study discusses the power control strategy in a standalone photovoltaic-battery hybrid system. The life-time of the battery will be shorter if the battery is often charged with high current and exceeds its State-of-Charge (SoC). Therefore, a control method is needed to control the power flow on the DC bus and the charging current as well as the SoC of the battery so that the battery has a long life-time. The proposed system uses two dc-dc converters to connect photovoltaic (PV) and lead-acid batteries to the load. The unidirectional DC-DC converter is used as the interface between the PV and the DC bus, the bidirectional DC-DC converter is used as the interface between the battery and the DC bus. The control strategy plays a role in controlling the power flow between the converter and the load to maintain the balance of power in the system and controlling the battery to support PV when the available PV power is not enough to meet the load. The multi-loop control strategy is proposed in this study, one of the loops is used to maintain the SoC of the battery in order to control the PV output power to avoid over-charging. Another loop is used to ensure the balance of the system's power when the battery is charging at its maximum charge current. The proposed control system is implemented without requiring any conditions for the control to operate. The simulation results show that the proposed multi-loop control can control the power flow in the system while maintaining the maximum charging current and battery SoC limits.