Distributed Control Scheme for a 11-Level Modular Multilevel Converter in a Grid Connected Photovoltaic Power Conversion System
- Resource Type
- Conference
- Authors
- Adams, Stephan; Sera, Dezso; Walker, Geoff; Broadmeadow, Mark
- Source
- 2022 IEEE 7th Southern Power Electronics Conference (SPEC) Power Electronics Conference (SPEC), 2022 IEEE 7th Southern. :1-6 Dec, 2022
- Subject
- Communication, Networking and Broadcast Technologies
Power, Energy and Industry Applications
Robotics and Control Systems
Signal Processing and Analysis
Transportation
Maximum power point trackers
Photovoltaic systems
Current control
Multilevel converters
Voltage measurement
Decentralized control
Power conversion
- Language
- ISSN
- 2832-2983
In recent years multilevel modular cascade converters have become a promising technique to connect photovoltaic cells to the grid. The reason for this is that they allow for plug and play modularity (allowing expansion and reduction), can have multiple local maximum power points (MPPs) allowing the system to produce the maximum possible power even when the PV cells are partially shaded, and allow for a reduction in the output filter. While current control systems can produce individual maximum power point tracking (MPPT) for each module they do not allow for plug and play modularity. This paper proposes a module voltage balancing technique coupled with a global maximum power point tracker to achieve this dual goal. This was then tested on a 11-level modular multilevel converter at several different irradiance levels between different modules. These tests show that if all the modules have an irradiances of $1 kW/m^{2}$ then a total MPPT efficiency of 98.8-100% and an individual MPPT efficiency of 98.8-100% was achieved. It also showed that as long as the number of modules with irradiance difference is minimal and the location of these modules with irradiance differences is optimal, then the global efficiency is maintained with only slight difference in individual MPPT efficiency.