Abstract
To fulfill requirement of connecting transmission lines at different voltages in DC grids, a modular multilevel DC/DC (MMC DC/DC) converter based on LCL tank is proposed. This converter combines merits of isolated MMC DC/DC and IGBT-direct-serial-based LCL-DC/DC converters. The converter topology is described and its working principle analyzed. Following that, determination of the LCL tank parameters in the converter is proposed on basis of power transfer and harmonics mitigation. Control and protection strategies applicable to the converter are brought up to transfer power with zero reactive power flowing from one side of MMC to another and to limit DC fault currents. This topology and the control and protection strategies are verified with Matlab/Simulink. Results show that the proposed control strategy makes the converter exhibit good static and dynamic performance under different operation conditions. Fault current can also be limited with the protection strategy.
| Original language | English |
|---|---|
| Pages (from-to) | 1106-1113 |
| Number of pages | 8 |
| Journal | Dianwang Jishu/Power System Technology |
| Volume | 41 |
| Issue number | 4 |
| DOIs | |
| State | Published - 5 Apr 2017 |
Keywords
- DC grids
- DC/DC converter
- LCL resonant tank
- Trapezoidal wave operation mode
- Zero reactive power control