[Interview] How Does National Semiconductor Boost Solar Power System Efficiency?

Jul 25, 2008
Katsumi Yamashita, Nikkei Electronics

National Semiconductor Corp of the US developed the "SolarMagic," a technology to boost the performance of solar power systems, and started field testing in Calif, the US.

The SolarMagic can increase the volume of power generated by existing solar power systems by up to 45%, the company said.

How does the technology increase the amount of power generated? Nikkei Electronics interviewed Jeff Waters, who is the president of the company's Japanese unit, about the technical content of SolarMagic and some other matters.

Q: What methods does SolarMagic use to raise the amount of power generated by solar power systems? Can you explain it in detail?

Waters: We realized SolarMagic making the most of our analog semiconductor technology. It is in the form of a module, not a standalone IC. The module houses intelligent analog ICs and other technical components. This module is connected with each solar cell module (including multiple solar cells) when used. Accordingly, a system combining three solar cell modules in series and two in parallel requires six SolarMagic modules.

The SolarMagic module prevents the solar power system's power generation from decreasing due to shade caused by buildings and trees, for example. Existing systems have enabled an overall solar power system to generate power by bypassing solar cell modules in shade using diodes.

In other words, bypassed solar cell modules make little contribution to power generation. SolarMagic allows such solar cell modules in shade to help power generation. The amount of power generation increases as a result.

SolarMagic has another effect to minimize the negative impact caused by mismatches among solar cells. A mismatch is the variation of power generation performance among solar cells. As the solar cell module connects cells in series, all cells' performance will be limited if a cell with poor performance is included. The SolarMagic module enables solar cell modules to exert their maximum performance.

Q: What controls does the SolarMagic module execute?

Waters: Power gained from solar cells is not always stable. Generated power widely varies depending on cell voltage. In other words, certain cell voltages maximize power generation. Those voltages are called MPPs (maximum power points).

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