What are the advantages and disadvantages of using distributed maximum power point tracking (DMPPT) in a large-scale solar power plant, and how does it affect overall energy yield?

Distributed Maximum Power Point Tracking (DMPPT) involves implementing MPPT at the module level or string level, rather than at the entire array level as with central inverters. Microinverters, DC-DC converters integrated into modules, or string inverters with multiple MPPT inputs exemplify DMPPT. A significant advantage of DMPPT is improved energy yield, particularly in conditions with shading, module mismatch, or varying orientations. By optimizing the operating point of each module or string independently, DMPPT minimizes losses due to these non-uniformities. If one module is shaded, it won't drag down the performance of the entire string. Another advantage is enhanced monitoring and diagnostics. DMPPT systems provide granular data on the performance of individual modules or strings, enabling faster identification and resolution of problems. For example, a degraded module can be quickly identified and replaced. A disadvantage of DMPPT is higher upfront cost. Microinverters and DC-DC converters add to the per-module cost. Also, increased complexity in the system design and installation must be considered. There is an increase in the number of components in the system, which might increase the probability of failure. This increased complexity could also make maintenance more difficult and expensive. The impact on overall energy yield depends on the specific site conditions. In sites with minimal shading and module mismatch, the energy yield improvement from DMPPT may be marginal and not justify the increased cost. However, in sites with significant shading or module variations, DMPPT can lead to a substantial increase in energy production, making it a cost-effective solution. DMPPT typically leads to greater energy harvest in locations that experience frequent cloud cover.