Power electronic converters

Contracting authority is publishing direct award notice for 'Power electronic converters'.

BACKGROUND INFO To advance research in energy and electrification, Tampere University is in the process of expanding its laboratory infrastructure with funding from the Research Council of Finland. As part of the interdisciplinary project “Digital electrification infrastructure”, a laboratory setup is being developed for the testing of electrical drive systems, benefiting both research and educational purposes. This setup comprises of two back-to-back connected electrical machines, one functioning as a motor and the other as a generator. The first machine is powered by an active front end (AFE) and an inverter unit (INU). The second machine is driven by an changeable inverter connected to a DC-link, which is powered by an AFE and a DC/DC buck converter such that its voltage can be adjusted over a wide range. Both AFEs are connected to a 400 V 3-phase grid. NEED Focus is the purchase of the following essential components to complete the test setup: two active front ends (AFEs), one inverter unit (INU), one DC/DC buck converter, two LCL filters, one set of DC filters, and two pre-charge circuits. Technical specifications: • The AFE and INU connected to the first machine should be IGBT-based two-level voltage source converters capable of supplying a three-phase four-pole permanent magnet synchronous machine with a rated voltage of 400V, rated shaft power of 200 kW, rated speed of 3800 rpm, and a maximum speed of 8000 rpm. The current rating is 295 A at 3800 rpm and 347 A at 8000 rpm. • The maximum DC-link voltage required between the AFE and INU is 750 V. • The INU should be compatible with the Heidenhain ECN 413 Speed Encoder (2048 SinCos signals, max. 200 kHz). • The AFE and DC/DC buck converter connected to the second machine should be capable of handling a DC-link current of 1000 A. • The frequency converters should facilitate bidirectional power flow. • The DC-link between the DC/DC buck converter and the changeable inverter should support a voltage range from 50 to 750 V. • All converters must be water-cooled and should function with a constant water inflow and simultaneous drainage, without the need for a heat exchanger unit. • The converters must include the manufacturer's control system, with the possibility to modify the INU to allow external control of the IGBTs using optical signals for future research purposes. • The converters must comply with IEC standards and be functional within ambient temperatures ranging from -10 to 40 °C. • The LCL filters, DC filters, and pre-charge circuits must be compatible with the designed setup, with air cooling being sufficient. • Pt-100 temperature sensors must be installed in the provided DC filters. MARKET ANALYSIS AND CONCLUSION FOR DIRECT AWARD Meeting all the specified requisites and the ability to provide all required components is mandatory of been selected in this procurement process. Frequency converters in the VACON NXP water-cooled product range are to be procured from the selected supplier, along with the necessary filters and pre-charge circuits. One of the key requirements is the variability of the DC-link voltage connected to the changeable inverter over a wide range. This capability is essential for testing different motor-inverter packages. The selected supplier exceeds this requirement by facilitating the DC-link voltage to vary between 25 and 775 V. Additionally, the ability of the machine-side converter (INU) to switch between the default manufacturer controls and external controls implemented using optical signals was a significant factor in the selection process. A wind generator setup with a similar component layout installed at the Tampere University laboratory includes frequency converters of the same model from the selected supplier which facilitate external controllability. This setup incorporates a separately fitted bus-adapter / option board to facilitate the control of IGBTs from optical signals. However, the high-power frequency converters selected for the new setup are pre-installed with optical connections, ensures the required external controllability without the need for additional modifications. The selected frequency converter range guarantees the use of tap water as one of its coolants, supporting the need of the use a continuous flow of water with the exemption of the use of a heat exchanger. The full setup provided by the selected supplier meets the needs all essential components, ensuring the system remains simple but effective. The VACON NXP frequency converter range has also proven to be robust are well-suited for research and educational purposes as demonstrated by its use in the wind generator setup, hydraulics lab setup, and solid-state transformer setup at Tampere University. Due to the aforementioned high technical requirements, only the specific supplier can be considered. Reasonable alternatives or substitute solutions do not exist, and the absence of competition is not due to an artificial narrowing of purchase conditions. The contracting authority has the right to set a quality level based on its own needs which products or services must implement.