Department of Mechanical and Manufacturing Engineering www.m-tech.aau.dk
4th Student Symposium on Mechanics and Manufacturing Symposium, 2016
Assembly and Control of Double U-core Switched Reluctance Motor
C. Poulose, K. B. Jensen, M. M. Madsen, P. Sloth-Odgaard, R. A. Hertz, S. Valentin-Pedersen Dept. of Mechanical and Manufacturing Engineering, Aalborg University, DK
1. Introduction The use of ammonia in cooling systems constitute a health and environmental risk. Johnson Controls has developed a patented multi stage cooling system that utilize water but requires varying impeller speeds to get the same cooling effect as ammonia The main scope of this project is to realize a prototype single phase double U-core switched reluctance motor (SRM) and develop control strategies to investigate the performance, in order to prove the possibility of such a system in the compressor solu- tion developed by Johnson Controls. Performance requirements: Minimum torque output of 30 Nm at 14300 RPM. Minimum input/output efficiency of 90% for the
3. Modelling and Control
4. Conclusion The prototype is modelled, assembled and successfully tested in the laboratory using the proposed control strategies, implemented on a DSP using C-code. The AHB inverter was subjected to multiple tests, which indicates that the designed functionalities work as intended. It is possible to switch the transistors with more than 10 kHz.
Acknowledgement The authors of this work gratefully acknowledge Sintex for sponsor-ing the 4th MechMan Symposium
The double U-core SRM concept employ a segmented stator design in the form of a U-shape.
Electrical sizing of the motor is optimization to 24 turns - Cost function: 30 Nm at 14300 Efficiency of >90 % - Objective function: Current Firing angles Skin and proximity effects are taken into account
2. System overview
Nonlinear motor model, including FEM based lookup tables, mechanical losses and impeller load torque.
System controlled with PI current and -speed cascade control: The current controller is verified using a step input of 4 A and
the speed controller with a step input from 250 RPM to 350 RPM.
An asymmetric H bridge inverter(AHB) is assembled to drive the SRM. The inver- ter is controlled by interfaced with a digital signal processor (DSP) - DC link: 563 V - Peak current: 660 A
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