Load Sharing and Voltage Restoration Improvement in DC Microgrids with Adaptive Droop Control Strategy

DC microgrid is a connecting network between distributed DC generators. The converter control on DCMG is used to obtain proportional load sharing and voltage restoration of DC bus. The traditional droop control is a common control technique in DC microgrid networks with multiple unit converters. However, this technique has limited performance when the difference of the line resistance is considered. In this paper, the intelligent adaptive droop control is proposed to improve the accuracy of load sharing, while the distributed secondary loop is utilized to minimize the DC bus voltage deviation. The droop resistance is tuned using fuzzy logic controller so that the load power sharing error compensation is obtained, while the DC bus voltage deviation is reduced by the PI controller. The exchange of output currents between converter units through communication lines is considered to obtain the actual load current conditions. The proposed droop control strategy can guarantee the load power sharing balance between three sources with a ratio close to 1:1:1. The results of the comparison analysis between the proposed technique and the traditional droop control are simulated completely using Matlab/Simulink, even under fluctuating loads and the line resistance changes

Building an Unmanned Aerial Vehicle for Humanitarian Aid Delivery

When an emergency occurs, immediate responses are needed for the affected areas. Conventional means of transportation often face difficulties carrying supplies to the location in need, especially in severely damaged areas.In this project, a small semi-autonomous unmanned aerial vehicle (UAV) was designed and constructed to undertake a representative humanitarian aid mission. The system has a novel hex-rotor design with overlapping propellers. Half of the motors have been turned upside down with a slight overlap between each propeller, hence reducing the total dimension of the system without losing its efficiency. The system is also equipped with a new lightweight servo activated two ring release system, allowing it to carry and release two kilograms of payloads with only small physical force needed.Overall, the system is capable to operate automatically while performing a series of tasks such as navigate waypoints and deliver payloads before returning to base. the system created in this project could deliver two individual payloads of 1 kg each to the pre-destinated target almost autonomously. The system provided promising results that encourage the utilization of UAV for delivering Humanitarian Aid

PV Generation-Energy Storage Coordination With Adaptive Droop Control In Isolated DC Microgrid

Photovoltaic (PV) generators and energy storages are critical components for supplying electricity and ensuring system stability, particularly in isolated DC mi-crogrid. Coordination of PV generators and energy storages plays an important role to avoid voltage instability, overcharge and overdischarge of energy storages. To develop PV generators-energy storage coordination, this paper proposes a distributed control method based on the SoC (state of charge) battery level and the DC bus voltage signalling. The proposed control method is equipped with adaptive droop control for both energy storage system and PV generators. Droop control for energy storage is responsible for ensuring the balance of stored energy, which can avoid overcharging or deepdischarging of certain energy storage units. Meanwhile, droop control for PV is used to minimize load sharing error when line resistance is considered. To restore the DC bus voltage due to the use of droop control, secondary control is also proposed in this paper. The results of the pro-posed technique are simulated completely using Matlab/Simulink, even under fluctuating PV power and the load changes

PENGARUH ARUS KAS PERUSAHAAN, DIVIDEN, DAN NILAI TAMBAH EKONOMIS TERHADAP VOLUME PERDAGANGAN SAHAM

Bob Suryoatmojo, 2019: The Influence of Firm Cash Flow, Dividend, and Economic Value Added on Stock Trading Volume. Universitas Negeri Jakarta This study aims to examine the influence of operating cash flows, investing cash flows, financing cash flows, dividends, and economic value added on stock trading volume. This study uses secondary data with the population of manufacturing companies listed on the Indonesia Stock Exchange for the period 2015-2017. Through purposive sampling technique taken 67 samples for 3 years which were processed by regression data panel analysis using Eviews 10. From the analysis perfomed in this research, it can be concluded that operating cash flow has positive significant effect on stock trading volume. Investing cash flow, financing cash flow, dividend payout ratio, and economic value added has no significant effect on stock trading volume. Independent variable in this research are able to explain of 15.04% to stock trading volume as the dependent variable. Keywords: Operating Cash Flow, Investing Cash Flow, Financing Cash Flow. Dividend Payout Ratio, Economic Value Added, and Stock Trading Volume

Analisis Implementasi Saturated Iron – Core Superconducting Fault Current Limiter pada Jaring Distribusi PT. PERTAMINA RU V BALIKPAPAN.

Pada studi ini akan dilakukan analisis hubung singkat pada sistem distribusi PT. PERTAMINA RU V. Analisis hubung singkat dilakukan pada bus utama PT. PERTAMINA RU V dengan rating 6,6 kV dan melihat pada bus mana yang tidak mampu menahan besarnya arus gangguan karena adanya retrofit generator STG I-4 yang terhubung pada sistem kelistrikan PT. PERTAMINA RU V. Saat terjadi gangguan hubung singkat 3 fasa peak pada bus 2HT dan 3HT, rating bracing peak pada bus sebesar 78,75 kA tidak mampu menahan arus gangguan sebesar 84,72 kA. Agar tidak terjadi kerusakan pada bus tersebut, maka diperlukan sebuah device pembatas arus gangguan yaitu Saturated Iron – Core Superconducting Fault Current Limiter (SISFCL). SISFCL dipasang pada satu incoming yang terhubung ke bus 2HT dimana pada incoming ini menyumbang arus kontribusi. Setelah dipasang SISFCL, nilai arus gangguan pada bus 2HT dan 3HT berkurang dari 84,72 kA menjadi 73,12 kA. Arus gangguan pada incoming yang dipasang SISFCL juga akan berkurang sehingga setting koordinasi proteksi untuk rele arus lebih juga akan berubah untuk itu diperlukan setting ulang pada beberapa rele. Setting ulang rele ditunjukkan pada kurva TCC ( Time Current Curve)

Perbaikan Faktor Daya Menggunakan Cuk Converter pada Pengaturan Kecepatan Motor Brushless DC

Brushless DC motor (BLDC) adalah mesin listrik yang sangat serbaguna. Secara konstruksi, BLDC adalah motor sinkron dengan gulungan ketat dan magnet permanen dipasang pada rotor. Dengan tidak menggunakan sikat dan komutator, sikat kerusakan dan percikan api tidak ditemukan di motor ini dan membuat BLDC lebih efisien daripada jenis lain dari motor listrik. BLDC digunakan dalam berbagai aplikasi, seperti aplikasi rumah tangga, transportasi, aerospace, pemanasan, ventilasi, robotika, dan banyak lainnya. Dalam operasi BLDC menggunakan sumber AC, rectifier ​​dan menghubungkan kapasitor umumnya digunakan. Dan juga, karena BLDC perlu gelombang saat persegi untuk bekerja, penggunaan inverter diperlukan. Inverter juga digunakan untuk tujuan kontrol kecepatan di kontrol kecepatan BLDC konvensional. Kontrol kecepatan konvensional yang hanya menggunakan DBR dan inverter menghasilkan harmonik yang besar yang berarti mengurangi faktor daya juga. Untuk mengatasi masalah ini, dapat digunakan DC-DC konverter antara rectifier dan inverter. Pada penelitian ini akan diteliti pengaruh mode Cuk Converter sebagai penghubung antara DBR dan inverter terhadap faktor daya sumber