Photovoltaic-based DC microgrid with partial shading and fault tolerance

Partial shading is a common problem that affects bus regulation in DC microgrids with several photovoltaic (PV) modules as energy sources, as a result of reduced solar irradiance reaching the modules. The problem can be mitigated by incorporating batteries, but if they are not included, appropriate control strategies must be used. This paper presents a new approach in a PV-based DC microgrid, which provides a high quality bus voltage regulation in islanding mode, without being affected by partial shading or problems associated with PV module connection and disconnection. The solution proposed herein ensures a proper voltage regulation without being affected by problems such as failures in PV modules or mismatch between them. Besides, it can help to prevent PV partial shade stress by disconnecting the modules affected. A further advantage of the approach is the flexibility to connect more PV modules. The advantages of this approach were verified in a 200 W prototype.