|关键词: solar, frequently asked questions, faqs|
Maxim's submodule optimizers are highly integrated DC-DC converters that replace traditional bypass diodes. The optimizers limit the PV module output voltage and output current to enhance system design flexibility as well as eliminate the impact of series and parallel mismatch frequently present during system operation. Rather than completely bypassing an underperforming cell string, the Maxim device actively harvests the available power and regulates the cell string's output current. This ensures that the underperforming cell string can always contribute power without impacting the output of the highest performing cell strings.
There are several key differences between Maxim’s submodule optimizer and other solutions that attach to the outside of modules (i.e., DC optimizers or microinverters). First of all, the Maxim solution is integrated directly into the PV module and does not require any additional equipment, such as communication devices, or specialized inverters to operate. The Maxim optimizers provide a broadly compatible and low-cost solution to increase module string length (reduce system capex), enhance system design flexibility, and mitigate losses due to module mismatch and long-term degradation.
Maxim's solution was designed to work with standard string inverters—both transformer-based and transformerless. The optimizers operate each cell-string within the module at their unique maximum power point while the inverter operates the overall array at the global maximum power point. With this division of maximum power point tracking responsibility, the system is guaranteed to always deliver all available power.
The speed at which the Maxim optimizers perform MPPT is considerably faster than that of the inverter, allowing both systems to work seamlessly together.
Maxim optimizers limit the maximum output voltage of a module, allowing a significant increase in the number of modules allowed in series while remaining under the high voltage safety limits. Furthermore, PV modules can be placed in partially shaded areas or face multiple directions without an energy production penalty.
The Maxim IC is a one-for-one replacement of the diode. The devices have similar reliability characteristics and have little statistical impact. The chip-level power solution is based on Maxim’s proprietary power semiconductor platform, with several billion similar shipped and functioning in similarly harsh environmental conditions. In practical applications, the Maxim device ensures that power is always harvested from its associated cell string. This eliminates the possibility of hot spots and bypass diode heating, thus increasing the reliability of the other module components. Furthermore, because of the MPPT granularity, long term module and system degradation can both be significantly reduced.
Maxim's highly integrated three-chip solution can be compared to board-level solutions containing hundreds of discrete components. Maxim's solution provides a significant statistical and practical reliability improvement over these complex implementations.
The PV module manufacturers selling Maxim-enabled modules provide warranties identical to their conventional counterparts. Based on extensive reliability assessments, leading manufacturers have concluded that Maxim devices meet their high standards for quality product components.
Maxim has enabled a turnkey J-box solution that can be quickly integrated into a conventional module design for testing, certification, and production. Please contact Zerun for samples, module design and testing guidelines, and commercial terms.
Software modeling tools, such as Aurora,PVsyst, and PV*SOL, can provide simulations for Maxim-enabled modules, which can be compared to standard modules or modules with alternative panel optimizer technologies.
SAM and PVWatts Calculator are general reference tools and not specifically designed for systems with shade. The software asks for losses in % of energy, which is a blanket entry based on the designer's assumptions about energy loss. For Maxim-enabled modules, you may consider reductions in percentage loss for soiling or mismatch assumptions over standard modules. An alternative approach is to use Aurora Solar or PVsyst.
Maxim's optimization solution is a simple, low-cost, industry-compatible technology to increase energy harvesting that lowers the cost of energy. To keep this solution simple, we do not add complex communication networks or wireless gateways, which can add complexity and cost to a project. If you need monitoring, you can get string-level, revenue-grade monitoring from most string inverter solutions on the market today.
|© Feb 27, 2017, Maxim Integrated Products, Inc.|
APP 6403: Feb 27, 2017
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