TMEIC: Pioneer of Large-capacity PV Inverter (1) (page 2)
Advanced power electronics technology improves power generation capacity
Fig. 4: The "3-level converter circuit" has four power semiconductors (IGBTs). Switching loss is substantially smaller compared with conventional circuits, leading to improvement in efficiency. (source: TMEIC)
In the production line, one worker skillfully assembles multiple parts and sends the assemblies to the next process. After completion, the PV inverters undergo a final inspection before they are ready for packaging and delivery (Fig. 2 & 3).
"We could respond to the rapid growth in the market because we had development and production bases established for the UPS (uninterruptible power supply) systems," said Naoki Fujiwara, group leader at the PV Technology Group, PV Project Promotion Office, Power Electronics Department, TMEIC.
At the Fuchu Complex, UPSes are manufactured in Building 46, which is adjacent to the building that accommodates the PV inverter production line. UPSes are used to protect servers at data centers, etc, in the event of a power failure, and the structure is very similar to that of PV inverters. PV inverters convert the direct current of solar batteries to alternating current. On the other hand, UPSes convert the alternating current of commercial power to direct current and input/output the current in/from batteries for another conversion to alternating current. TMEIC utilizes the design concept and quality of UPSes, which need to be highly reliable, in PV inverter development and production.
Leads industry through conversion efficiency improvement
At the complex, power semiconductors called IGBTs (insulated gate bipolar transistors), delivered from Mitsubishi Electric Corp, are attached to PV inverter and UPS units after the inspection process. The IGBT is a semiconductor element that controls the "switching" for quick current on/off operation and is the heart of the PV inverter and UPS systems, which convert electric current from direct current to alternating current.
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