Thesis Defense - Mert Serdar Bilgin (MSEE)

Mert Serdar Bilgin - MSc., Electrical Electronics Engineering

Asst.Prof. Göktürk Poyrazoğlu - Advisor

INVESTIGATION ON THE EFFECTS OF DC-LINK
CAPACITORS TO DC/AC CONVERTER UNDER
VARIOUS OPERATION CONDITION

Date: 29.05.2019

Time: 10:00

Location: AB2 G12

Thesis Committee: 

Asst.Prof. Göktürk Poyrazoğlu,  Özyeğin University

Assoc. Prof. Fatih Uğurdağ,  Özyeğin University

Assoc. Prof. Mutlu Boztepe,  Ege University

Asst.Prof. Ahmet Tekin,  Özyeğin University

Asst.Prof. Özgür Tamer,  Dokuz Eyül University

Abstract

In the designing stage of a DC/AC converter, determining parameters of components has an essential role such as value, size and material type. DC-Link capacitors are the critical components for DC/AC converters and define the lifetime of the converter. A grid-connected converter must provide related standards and grid regulations done by operating country even though poor operating conditions. Effective power generation through a grid-tied DC/AC converter faces many challenges that cause less lifetime and improper working of the device due to several factors including but not limited to unstable grid voltage, change of DC input voltage and different power factors. Grid voltage unbalance causes higher THD values on grid currents than normal grid conditions. THD value of grid current is limited by the IEEE 519- 2014 standard. Unstable grid conditions show different results because of the value
and type of DC-Link capacitors. In this thesis, after the introduction of topologies, basics of control methods, PWM methods of a DC/AC converter then two types of capacitors (electrolytic and film capacitors) are compared with different grid voltage conditions and power factor values for grid-tied 10 kVA DC/AC converter. On the other hand, the lifetime calculation theory of an electrolytic capacitor is interpreted and calculations are done for electrolytic capacitors in different operating conditions.

Lastly, an unbalance voltage controller added to the system to observe effects on output current quality for an electrolytic DC-Link capacitor. All the work is done by simulation software PLECS, results are compared and explained.

Bio

Mert Serdar Bilgin was born in 1992 in Denizli. He received D.Sc degree of Electrical and Electronics Engineering from Dokuz Eylul University in 2016. He is a Power Electronic Hardware Design and Control Engineer. He has the experience to design voltage source inverters, DC/DC converter topologies, experience to analyze engineering problems, evaluate designs and recommend alternatives. He has a good understanding of hardware product development design and closed-loop control algorithm development. He has been working at Vestel Electronic R&D department.