One manufacturer of solar micro inverters offers a new model that it says will double the life of a solar PV system without adding cost. Enecsys Limited’s 480-W Enecsys Duo micro inverter supports fully independent power point tracking of two photovoltaic modules when converting the DC output of the PV modules to grid-compliant AC.
The inverter, along with its 360-W version, bring the capital costs of solar PV systems down to those of systems based on string inverters. However, string inverters typically need to be replaced at least once during the lifetime of the system, while Enecsys says its micro inverters are expected to have a service life of over 25 years and come with a 20-year limited warranty, double the reliable operating life of solar PV systems based on string inverters.
As with other Enecsys micro inverters, the SMI-D480W-60 and SMI360W-60 operate in real world conditions over an ambient temperature range from -40 to +85 degrees C. The micro inverters mount on the rails behind each solar module, either one per module or, in the case of the Duo models, one for every two modules. With a patented design that eliminates electrolytic capacitors, the most life-limiting components in inverters, the manufacturer says their reliability has been verified through industry-standard test methodologies including HALT, HASS and HTOL. The inverters have also been subjected to thermal cycling to IEC61215 standards, the same methodology used to test solar PV modules.
Micro inverters enable maximum power point tracking (MPPT) to be applied individually to each PV module to ensure maximum energy harvest. Solar PV systems based on micro inverters do not suffer from dramatic reductions in output when a module, or part of a module, has its output reduced by shading or build-up of surface debris. As a result, Enecsys says their micro inverter systems extract between 5% and 20% more energy over the lifetime of the installation, compared with traditional residential and commercial solar PV systems using string inverters. The degree of improvement depends upon the system layout and the installation site.
Products within the Enecsys micro inverter family are safety and EMC tested and certified to EN 62109, G83, UL1741, TUV and CE. Country-specific requirements, including VDE V 0126-1: 2006 compliance, are achieved through the use of specific Enecsys installation products. Each micro inverter has a built-in ZigBee wireless monitoring system to provide real-time and historical data on the performance of every individual solar module. When connected to the Internet via the Enecsys Gateway, this enables online monitoring of system performance from anywhere in the world.