February 2011
Intermediate
416 pages
11h 24m
English
2
Photovoltaic Inverter Structures
2.1 Introduction
The PV inverter is the key element of grid-connected PV power systems. The main function is to convert the DC power generated by PV panels into grid-synchronized AC power.
Depending on the PV power plant configuration, the PV inverters can be categorized as:
- Module integrated inverters, typically in the 50-400 W range for very small PV plants (one panel).
- String inverters, typically in the 0.4-2 kW range for small roof-top plants with panels connected in one string.
- Multistring inverters, typically in the 1.5-6 kW range for medium large roof-top plants with panels configured in one to two strings.
- Mini central inverters, typically > 6 kW with three-phase topology and modular design for larger roof-tops or smaller power plants in the range of 100 kW and typical unit sizes of 6, 8, 10 and 15 kW.
- Central inverters, typically in the 100-1000 kW range with three-phase topology and modular design for large power plants ranging to tenths of a MW and typical unit sizes of 100, 150, 250, 500 and 1000 kW.
Historically the first grid-connected PV plants were introduced in the 1980s as thyristorbased central inverters. The first series-produced transistor-based PV inverter was PV-WR in 1990 by SMA [1]. Since the mid 1990s, IGBT and MOSFET technology has been extensively used for all types of PV inverters except module-integrated ones, where MOSFET technology is dominating.
Due to the high cost of solar energy, the PV inverter technology ...
