Ampt said that its patented String Optimizers are being deployed in 600 volt photovoltaic (PV) solar systems at installed costs in cents per watt that rival that of 1000 volt systems. Ampt String Optimizers are designed to allow the use of 1000 volt inverters that are claimed to lower inverter cost by 40% and also reduce DC BOS costs by 50%.

Problem

600 volt systems continue to be deployed due to application type (like rooftops) or code adoption cycles across local jurisdictions in the US market. In some cases, 600 volt systems are used to take advantage of significantly lower cost 600 volt PV modules, or because they are grandfathered in under the 1603 Treasury Grant Program. However, lower cost and higher power from systems can be achieved to lower when deployed with 1000 volt inverters.

Solution

Ampt String Optimizers are DC-to-DC converters that are being deployed with 1000 volt inverters at their full-rated power in 600 volt National Electrical Code (NEC)-compliant systems. These inverters are claimed to be delivering 60% more power translating to a 40% reduction in inverter cost. In addition, fewer inverters are used, so AC cabling costs and labor decreases proportionally and are claimed to support the removal of 5 to 10 US cents per watt in total system cost installations in the US market. 

Applications

US residential rooftops deploying 600 volt (NEC) compliant PV systems.

Platform

Ampt's patented ‘String Stretch’ technology allows PV strings to be twice as long as in other NEC-compliant systems. Doubling the number of PV modules per string reduces the number of combiners, disconnects and associated labor by 50%. 

Availability

June 2015 onwards. 

Tags: string optimizers, dc-to-dc converters

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