SLLA498A October   2020  – December 2024

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Solar String Inverters
    1. 2.1 Power Stages for DC/DC MPPT
    2. 2.2 Power Stages for Battery Port DC/DC
    3. 2.3 Power Stages for Single-Phase DC/AC
    4. 2.4 Power Stages for Three-Phase DC/AC
  6. 3Future Technology and Trends
  7. 4Summary
  8. 5References
  9. 6Revision History

1 Introduction

Solar string inverters are used to convert the DC power output from a string of solar panels to an AC power. String inverters are commonly used in residential and smaller commercial installations. Wide bandgap semiconductors like Silicon carbide (SiC) and Gallium nitride (GaN) allow to operate converters at higher switching frequencies which allows use of smaller magnetic components and in turn drive power density of these systems up. To scale power levels up very often such systems are made in modular fashion to get from 10th of kW to 100th of kWs.

To cope with the fact that Photovoltaic (PV)-systems stop generating energy when sun light goes down, these systems very often incorporate a power conversion port for a battery energy storage system (BESS). Excess energy generated during day time is stored into the battery and can be used during times the energy from the PV-string is not enough.