Abdullah Nur Aziz
Program Studi Fisika, Fakultas Sains dan Teknik, Universitas Jenderal Soedirman Jl. Dr. Suparno No. 61 Karangwangkal Purwokerto

Published : 2 Documents
Articles

Found 2 Documents
Search

Pemanfaatan Teknik Lissajous untuk Mengetahui Korelasi antara Kandungan Air terhadap Sifat Dielektrik Tanah (Studi Kasus: Sampel Tanah Permukaan di Sekitar Kota Purwokerto)

BERKALA FISIKA Vol 12, No 3 (2009): Berkala Fisika
Publisher : BERKALA FISIKA

Show Abstract | Original Source | Check in Google Scholar | Full PDF (329.833 KB)

Abstract

The equipment has been designed to measure the dielectric properties of soil samples with lissajous technique in Basic Physics Laboratory, Study Program of Physics, Faculty of Science and Engineering, University of Jenderal Sudirman, Purwokerto. The equipment has been used to measure the dielectric constant of 19 soil samples taken from several locations in area of Purwokerto city and its surrounding, at a frequency of 100 kHz. The measurement has been conducted on soil samples with the variation of soil mass water content. The results obtained indicate, the existence of a correlation between the dielectric constant of soil samples to the soil water mass content (h) which can be expressed with two equations; dielectric permittivity e = 0.3176 h-2.5555 with a correlation coefficient R2 = 0.9538, and dielectric loss equation e= 0.00003 h -5.3336 with a correlation coefficient R2 = 0.9513.

Five-level PWM Inverter with a Single DC Power Source for DC-AC Power Conversion

International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 8, No 3: September 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Original Source | Check in Google Scholar | Full PDF (495.129 KB)

Abstract

This paper presents a circuit configuration of five-level PWM voltage-source inverter developed from the three-level H-bridge inverter using only a single DC input power source. In the proposed five-level inverter, an auxiliary circuits working as the voltage balancing circuits of the inverter’s DC capacitors is presented. The auxiliary circuits work to keep stable DC capacitor voltages of the inverter, and also to reduce the capacitor size of the inverter. The unique point of the proposed balancing circuits is that it needs only a single voltage sensor to control the voltages of the two capacitors in the inverter. Moreover, a minimum number the inverter’s switching devices is also an important feature of the proposed inverter topology. A simple proportional integral controller is applied to control the voltage of the DC capacitors. The proposed topology is tested through computer simulation using PSIM software. Laboratory experimental tests were also conducted to verify the proposed inverter circuits. The computer simulation and experimental test results showed that the proposed balancing circuits works properly keeping stable voltages across the two DC capacitors of the inverter using only a single voltage sensor. The inverter also works well to synthesize a five-level PWM voltage waveform with sinusoidal load current.