Abstract
This paper discusses a grid-connected energy storage system based on two three-level (3L) converters: a DC-DC one and a neutral-point-clamped inverter. When compared to a system using standard two-level converters, the main advantages of this system are: higher efficiency, smaller reactive components allowing for a system cost reduction and its capability to handle higher voltage and power. A modulation strategy for the DC-DC converter which includes the neutral-point voltage balance control is proposed. The capability of the DC-DC converter to cancel the inverter's neutral-point voltage oscillations is also analyzed. Results are presented to illustrate the extended operation area without imbalances. Design guidelines to size the DC-link capacitors are given for a practical implementation. Experimental results taken from a 10 kW 3L DC-DC converter prototype are provided to show the capability of this particular converter to keep neutral-point voltage balance.
| Original language | English |
|---|---|
| Pages (from-to) | 14-22 |
| Number of pages | 9 |
| Journal | EPE Journal (European Power Electronics and Drives Journal) |
| Volume | 23 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2013 |
Keywords
- Converter control
- Energy storage
- Modulation strategy
- Multilevel converters
- Renewable energy systems
