A Tranformerless Grid-Connected Photovoltaic

这些都是光伏发电系统吧比较经典的论文,希望可以帮到大家。大概都是零八年以后的IEEE论文,有些方法运用比较经典。

A Tranformerless Grid-Connected Photovoltaic System with Active and Reactive Power Control

Su-Won Lee1, Jae-Hyung Kim2, Seong-Ryong Lee3, Byoung-Kuk Lee2, and Chung-Yuen Won2

1 Center for Advanced IT HRD with closed Industry Cooperation, Sungkyunkwan University, Suwon, 440-746, Korea

2 School of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746, Korea 3 School of Electrical and Information Engineering, Kunsan National University, Kunsan, 573-701, Korea

Also, considering the high cost of a solar cell panel, the transformerless type is suitable for the PV system [4],[5].

The conventional grid-connected PV system merely supplies the maximum active power from the PV array to the grid via an inverter. Today, non-linear loads are widely used in residential and office buildings. If the grid-connected PV system is applied to non-linear loads, the power quality is relatively poorer, because of the active power supply by the PV array.

To solve this problem, the grid-connected PV system should not only supply active power to the system via MPPT, but also improve the power quality (low THD and unity power factor). In the grid-connected PV system, which considers the power I. INTRODUCTION

quality, studies on the line frequency transformer type (Fig.

Nowadays, renewable energy resources are receiving

1(a)) are in progress, but studies on the transformerless type

attention as a solution to guarantee energy security and reduce

(Fig. 1(b)) are limited [6]-[10].

greenhouse gases, and large-scale research activity has been carried out in this field. Photovoltaic (PV) energy is becoming one of the most important renewable energy resources, since it is clean, generated on-site, pollution free and inexhaustible [1],[2]. Generally, a PV system is categorized into the stand-alone and grid-connected type. In the global market, a large proportion of PV solar power is supplied by the grid-connected type.

A conventional grid-connected PV system supplies the

(a) DC/AC inverter with transformer. maximum available active power from the PV array to the grid.

Fig. 1 shows the most widely used topologies of the grid-connected PV system. Fig. 1(a) consists of an inverter and a line frequency transformer. Even if this topology is simple, it has the disadvantage of the heavy weight and huge volume, because of the large line frequency transformer. The PV module has a wide operating voltage range, owing to the duration of the irradiance and temperature change. Therefore, the output (b) DC/AC inverter with DC/DC converter. voltage of the inverter is restricted by the minimum PV input Fig. 1. The topologies of PV system DC voltage. The PV system with two conversion stages, with a

In this paper, a transformerless grid-connected photovoltaic DC/DC converter as the first stage and a DC/AC inverter as the

second stage, is shown in Fig. 1(b). Although a non-insulation (PV) system with an active and reactive power control algorithm problem is inherent in Fig. 1(b), it is good for making low cost is proposed. The proposed system operations can be divided into and compact products. However, this topology needs a very sunny mode and night mode. In night mode, it compensates for high efficiency DC/DC converter for the high efficiency PV the reactive power demanded by nonlinear loads. In sunny system. Recently, a study on a non-isolated DC/DC converter mode, it not only supplies active power from the PV array to the with a high efficiency, by the soft switching method, was grid or loads, but also performs power quality control (PQC), to

improve the power factor and reduce the harmonic current. In released [3].

In order to supply the PV system on a global scale, the major order to verify the proposed system, simulation results are issue is the reduction in the cost and size of the inverter system. presented.

Abstract-This paper presents a transformerless grid-connected photovoltaic (PV) system with active and reactive power control. The proposed system operations can be categorized into sunny mode and night mode. In night mode, it compensates for the reactive power demanded by nonlinear loads. In sunny mode, it not only supplies active power from the PV array to the grid or loads, but also performs power quality control (PQC), to improve the power factor and reduce the harmonic current. Simulation results are provided to demonstrate the effectiveness of the proposed system.