| Title |
Suppression of Common-Mode Voltage in a Multi-Central Large-Scale PV Generation Systems for Medium-Voltage Grid Connection |
| Authors |
Young-Sang Bae ; Rae-Young Kim |
| DOI |
10.6113/TKPE/2014.19.1.31 |
| Keywords |
central inverter; medium voltage; common mode; leakage current |
| Abstract |
This paper describes an optimal configuration for multi-central inverters in a medium-voltage (MV) grid, which is suitable for large-scale photovoltaic (PV) power plants. We theoretically analyze a proposed common-mode equivalent model for problems associated with multi-central transformerless-type three-phase full bridge(3-FB) PV inverters employing two-winding MV transformers. We propose a synchronized PWM control strategy to effectively reduce the common-mode voltages that may simultaneously occur. In addition, we propose that the existing 3-FB topology may also have the configuration of a multi-central inverter with a two-winding MV transformer by making a simple circuit modification. Simulation and experimental results of three 350kW PV inverters in a multi-central configuration verify the effectiveness of the proposed synchronization control strategy. The modified transformerless-type 3-FB topology for a multi-central PV inverter configuration is verified using an experimental prototype of a 100kW PV inverter. |