With “National Semiconductor Acquires Act Solar, Extending Its Solar Energy Efficiency and Management Capabilities”, National Semiconductor Corporation (NSM) purchased a string based photovoltaic ((PV)) DC power optimization solution in favor of its overpriced module based product. Per “National Semi Buys Act Solar” by Ucilia Wang in the Green Light blog at Greentech Media, “National Semi declined to say how much it paid for Act Solar. Jenkins said it was an all-cash transaction.”
While the Act Solar Active Power Management Whitepaper describes the problems PowerString (datasheet, product overview) solves, it does not delve into the technology. As I understand it, PowerString senses the main solar array MPP (Maximum Power Point) voltage and monitors the string current to determine whether the string solar modules are generating maximum power. If any string solar modules are impaired or shaded, PowerString uses a Buck Converter arrangement to bias the unimpaired or unshaded modules at their MPP voltage thus recovering secondary and tertiary string power losses. The PowerString bucks the array MPP voltage to match the lower MPP voltage of the power generating modules.
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