Implementation of a High Efficiency Grid-Tied Multi-Level Photovoltaic Power Conditioning System Using Phase Shifted H-Bridge Modules

Implementation of a High Efficiency Grid-Tied
Multi-Level Photovoltaic Power Conditioning
System Using Phase Shifted H-Bridge Modules
Jong-Pil Lee†, Byung-Duk Min**, and Dong-Wook Yoo*
†*Power Conversion Research Center, Korea Electrotechnology Research Institute, Changwon, Korea
**Green Power Co. Ltd, Suwon, Korea
Abstract
This paper proposes a high efficiency three-phase cascaded phase shifted H-bridge multi-level inverter without DC/DC
converters for grid-tied multi string photovoltaic (PV) applications. The cascaded H-bridge topology is suitable for PV
applications since each PV module can act as a separate DC source for each cascaded H-bridge module. The proposed phase
shifted H-bridge multi-level topology offers advantages such as operation at a lower switching frequency and a lower current
ripple when compared to conventional two level topologies. It is also shown that low ripple sinusoidal current waveforms are
generated with a unity power factor. The control algorithm permits the independent control of each DC link voltage with a
maximum power point for each string of PV modules. The use of the controller area network (CAN) communication protocol for
H-bridge multi-level inverters, along with localized PWM generation and PV voltage regulation are implemented. It is also
shown that the expansion and modularization capabilities of the H-bridge modules are improved since the individual inverter
modules operate more independently. The proposed topology is implemented for a three phase 240kW multi-level PV power
conditioning system (PCS) which has 40kW H-bridge modules. The experimental results show that the proposed topology has good performance.
LINKS DOWNLOAD
http://www.koreascience.or.kr/article/ArticleFullRecord.jsp?cn=E1PWAX_2013_v13n2_296

Transformerless three-phase on-line UPS with high performance

Transformerless three-phase on-line UPS with
high performance
E.-H. Kim J.-M. Kwon B.-H. Kwon
Department of Electronic and Electrical Engineering, Pohang University of Science and Tech, Republic of Korea
E-mail: znight@postech.ac.kr
Abstract: A transformerless three-phase on-line uninterruptible power supply (UPS) is proposed. The proposed
UPS is composed of a rectifier, an inverter and a battery charger/discharger. The rectifier regulates a DC-link
voltage and performs power factor correction. On the other hand, the inverter provides a regulated sinusoidal
output voltage and has the current-limiting capability for an impulsive load. The battery charger/discharger
reduces the number of battery and supplies the power demanded by the load in the event of the input
power failure or abrupt decrease of the input voltage. Since both neutral lines of the input and output
voltages are connected at the centre of the DC-link, the need for an isolation transformer is eliminated and
the size, weight and cost of the system are significantly reduced. Additionally, new control algorithms of the rectifier, the charger/discharger and the inverter are proposed.
LINK
http://www.mediafire.com/view/7yl5uqoj5e3eq4s/TRANSFORMERLESS-UPS.pdf

Novel Two-Stage High-Power-Factor Electronic Ballast CHUN YUAN CHRISTIAN UNIVERSITY

Abstract

In this thesis, electronic ballast with power factor correction for high intensity discharging (HID) lamp is presented. The proposed topology is a two-stages circuit that requires only one switch and one inductor for each stage. Power factor correction (PFC) stage is boost dc-to-dc converter operating in continuous conduction mode (CCM) to achieve low total harmonic distortion (THD) and proper output characteristics over a wide range of load (10% ~ 90% full load).
This control implementation for against broken lamp can be easily implemented with the proposed circuitry. The high-frequency supply the lamp is given by the flyback converter. Input AC voltages ranges from 90V~260V are allowable for our system with a low DC bus voltage below 450V. It is suitable for electronic ballast with medium power HID lamp. The topologies could work under the circumstance of two 250W fluorescent lamps at 66 KHz switching frequency.
LINK
https://www.mediafire.com/?bc4y0332flfxltc

A STUDY OF CHARGING EQUALIZATION AND DISCHARGING POWER MANAGEMENT FOR SERIES AND PARALLEL CONNECTED BATTERY PACK

A STUDY OF CHARGING EQUALIZATION
AND DISCHARGING POWER MANAGEMENT FOR SERIES AND
PARALLEL CONNECTED BATTERY PACK

研 究 生： 蔡志明    Jr-Ming Tsai
指導教授： 李清元教授    Prof. Ching-Yuan Lee

Master Thesis Department of Electrical Engineering Tatung University

ABSTRACT
ABSTRACT

The object of this paper is to research the methodology of charging equalization and
discharging power management of the series and paralleled connected battery sets under the
considerations of the safety, economics and practicality to improve the overall battery sets
efficiency.  The battery management system used the isolation method to ensure the charging
equalization of batteries; and to protect from the abnormal situation during discharging of the
series-connected battery sets.  As for the parallel-connected battery sets, this paper proposes
a multi-mode chopper.  It will enable to control and distribute the output current from each
battery.
The serial and parallel connection scheme uses two batteries as the smallest unit.  The number of batteries may be expanded at will.  The system performs the charging and discharging tests of the serial and parallel connected GS LC18650 1800mAh lithium battery sets.  Finally, a single-chip microprocessor, PIC16F877 is use to implement the control method of the proposed system. Via the experimentation, it proofs that the methods can performs its feasibility and good characteristics as anticipated.

LINK FULL THESIS
https://www.mediafire.com/?rhvvhjqnr3io4ug

Enterprise-Scale UPS Protection for Medium and Large Data Centers