Danfoss has developed a new control algorithm for its VLT frequency converters that opens up for synchronous reluctance motors and heralds the "one VLT for all motors".
High efficiency synchronous reluctance is one of the newly-emerged motor technologies offering optimum energy utilisation. It is also a robust technology — maintenance requires little effort, so overall it can demonstrate an impressively short payback period in terms of return on investment.
When the diverse motor technologies within one plant are controlled by a single drive platform, the designer has full liberty to install the best value motor for each application, says Danfoss. At the same time, costs are reduced for both storage and training in operation of the frequency converter. And updating the system with the new motor technology is an easier retrofit, as no exchange of the drive is required.
These advantages, says Danfoss, are precisely the benefits that its VLT frequency converters offer. The VLT AutomationDrive is able to control a wide variety of motor types, now including synchronous reluctance. Control not only involves operating the motors using advanced Voltage Vector Control, but also the full realisation of the efficiency advantages. This realisation is possible due to specially adapted algorithms for operation at the optimum operating point.
New Danfoss firmware for synchronous reluctance means that commissioning is as easy as for a standard AC asynchronous motor — the installer has to enter only four motor parameters. The automatic motor adaptation for synchronous reluctance motors takes only 2.7 seconds to measure the motor characteristics and optimise the motor parameters. The motor then operates at the highest possible energy efficiency, for lower energy consumption and reduced running costs.
Danfoss’ “One VLT for all motors” approach enables motor independence including synchronous reluctance at no extra cost; whilst still ensuring optimal performance. The same frequency converter can be configured for operation of standard asynchronous machines, permanent magnet and synchronous reluctance motors — even existing installations can be upgraded with the new software.