Test Stand

Induction Machine Test Stand

The LSR has a general-purpose 3-phase induction motor test stand conceived for evaluating control algorithm performance in practice. The test stand incorporates off-the-shelf machines with industrial hardware and norm-compliant safety systems. High-performance power electronic modules and sensors together with a PowerPC-based embedded computer with real-time OS and associated development tools enable rapid development and online execution of even computationally-intensive algorithms.

The test stand mainly consists of a general-purpose drive and a configurable generator module. The drive is made up of a 7.5 kW squirrel-cage induction machine and a 12 kVA power electronic frequency converter and may deliver a given torque or emulate a relevant physical system such as a wind turbine. The drive is coupled via a shaft torque transducer to the generator module containing two 4 kW slip-ring induction machines. This module may be configured with switching logic as a single doubly-fed induction generator or as a cascade of two induction generators with electrically and mechanically coupled rotors. The latter configuration allows for investigation of control methods for a brushless doubly-fed induction generator. The majority of the generator's power is exchanged directly with the grid. The balance is coupled to the grid through a 12 kVA back-to-back frequency converter with integrated dc link. The generator control (e.g., rotation rate and delivered power factor) is implemented physically by setting this converter's power electronic switches at 16 kHz.

Main components:

• 7.5 kW, 4-pole squirrel-cage induction machine with integrated encoder and brake
• shaft torque transducer
• 12 kVA power electronic frequency converter with embedded torque controller
• two 4 kW, 4-pole slip-ring induction machines
• 12 kVA back-to-back power electronic frequency converter with integrated dc link
• 12.5 kVA autotransformer for reduced voltage operation
• temperature sensing and active cooling on all machines
• PowerPC-based embedded computer with real-time OS