As a true multi-biofuel district heating plant, Hjørring has a wide range of applications in use. When specifying the new plant, the operations manager recognized the benefits of SynRM motors over permanent magnet motors (which can be difficult and expensive to repair), and that they have superior efficiency over IM motors. However, at that time, SynRM motors with super-premium efficiency class IE4 were not widely commercially available. It was difficult to find a partner that could supply a single drive platform to control the different motor technologies used with the wide range of applications at the plant.
The project chose a Danfoss customized AC-drive development solution over an off-the-shelf drive-motor package from a competing supplier.
Software development was an important part of the solution. Danfoss Drives developed and tested an algorithm which was customized to the SynRM motors at the plant. The algorithm enables the drive to adapt to the motor in under three seconds during commissioning.
A total of 18 Danfoss VLT® AutomationDrive FC 302 AC drives are installed at the plant, and all drives are installed with PROFIBUS and 24V DC backup options. Based on required performance, Danfoss dimensioned the AC drives to match the specified motors. Each drive was selected for the individual load and application – pump or fan.
We like Danfoss products and were not hesitant about committing to a development process. At the beginning of the project, it was quite difficult to find an IE4 motor. However, nowadays, it's already realistic to specify IE4 motors.Gorm Gade Knudsen, Weiss
(performs project management, design and installation of combustion plants for biofuels)
Making the most of the compatibility of the VLT® AutomationDrive FC 302 with different motor types, Hjørring is one of the few district heating plants in the world to achieve high efficiency, world-class performance with 125% fuel utilization and parallel 2022 emission targets. This is the ultimate multi-biofuel plant.
By using SynRM instead of PM motors, the district heating plant saves on maintenance costs and increases motor uptime, which helps them achieve a really impressive 7-year ROI.
A lot of operational, maintenance and training time has also been saved since all the drives have the same user interface even though they control different motor types (both IM and SynRM) and different drive sizes/applications. Also, having one drive brand and platform ensures a reduced spare parts inventory.
payback on IE4 SynRM motors by comparison with traditional IE2 motors operating at partial load