Cost reduction and manufacture of the SunSine{reg_sign} AC module: Phase I Annual Report : 21 April 1998 -- 31 October 1999

This report summarizes the progress made by Ascension Technology in Phase 1 of the cost reduction and manufacturing improvements of the SunSine{reg_sign} AC Module. This work, conducted under NREL subcontract, is a two-phase effort consisting of investigations into improving inverter packaging, soft switching, circuit optimization, design for manufacturing, manufacturing processes, and pilot production manufacturing. The objective of this subcontract is to significantly reduce the cost of the SunSine{reg_sign} inverter, enhance its performance, and streamline and expand the manufacturing process. During Phase 1, the soft-switching topology was designed, then refined to meet stringent cost and performance goals. This design resulted in improved performance, smaller overall footprint, and reduced costs. The aluminum inverter housing was redesigned, and the decision was made to conformal coat the circuit boards, which was verified through the HAST (Highly Accelerated Stress Testing) method. Potential international markets were identified, and the inverter is designed to be easily modified to meet the requirements of other countries. Significant cost reduction and performance improvements have been achieved in Phase I, and accomplishments during Phase I include: (1) SunSine{reg_sign} AC Module costs have been reduced enough to be able to reduce the suggested list price; (2) successful implementation of soft-switching; (3) power circuit-board size reduced 53{percent}; (4) power circuit-board component count reduced 34{percent}; (5) total inverter parts count reduced 49{percent}; (6) anticipated inverter manufacturing cost reduced 57{percent} on a $/Wp rating; (7) transformer efficiency improved 1.4{percent}; and (8) inverter efficiency improved 4.7{percent} to 91.0{percent} at 275 Wac.