At the Solar Power International show in Chicago last week Danfoss introduced its QLX central inverter series for the utility-scale market, and its MLX solar inverter series for medium to large-scale solar projects. In case you missed the show, here’s a quick look at both.
QLX Central Inverter Series: An outdoor solution for the utility-scale market with a product range of 1 MW to 1.5 MW. With a NEMA 4 sealed inverter section, this series delivers maximum efficiency (up to 98%) without derating, even under harsh weather operation at ambient temperatures from -20°C to +50°C.
All inverter components remain cooled, due in part to its liquid cooled design for semi-conductors and inductors. This integrated technology is equipped with speed-controlled fans and pumps to avoid internal pollution and lengthen maintenance intervals – even in dusty regions. Liquid-cooled heat sinks keep the unit cleaner while variable speed controlled fans and pumps help the unit perform more efficiently. The inverter is also equipped with a dehumidifier for water vapor removal.
The inverter’s compact size and weight improves transport logistics. The unit is fully equipped and can be mounted directly to a concrete pad or skid together with a close coupled transformer. Installation can be completed safely and efficiently with designated cabinet functions and quick connections.
An LCD display shows the unit’s operating status, and a built-in data logger records and sends performance and operational data. It allows pyranometer, wind-speed indicator and temperature sensors to work in parallel. All data is recorded from each unit, stored and transmitted daily via modem or an optional Internet connection.
MLX Inverter Series: The MLX is neither a string inverter nor a central inverter, it combines the best of both worlds. An international solution, the MLX is designed for medium to large-scale commercial applications in multi-region grids and climates.
Compact and lightweight, the MLX delivers high yields and do note require an inverter pad. The MLX can quickly mount directly on to PV-array racks. It’s designed for multi-region grids with 3-phase 208 Vac, 400 Vac or 480 Vac grids of 50/60Hz.
With an open communication interface based on industrial standards, the MLX is Sunspec Alliance compliant and easy to integrate into control and monitoring systems.
Optimized for 1000Voc DC layouts and with the need for DC-boosting eliminated, efficiency of over 98% is available. Three power sizes, 30, 45 and 60 kVA will be available, and, depending on PV module architecture, the MLX-60 can handle up to 16 PV strings via an external string combiner.
The MLX is designed to offer a lean service model. Intelligent inverter monitoring enables easy and efficient troubleshooting. As with string inverters, the compact MLX allows for simple exchange-and-return service, eliminating the need for a maintenance contract. Standard off-the-shelf components and pre-built solutions can be used with the MLX.