Rotodynamic study of a high speed switched reluctance generator

High speed generation derives its motivation from a variety of applications such as concentrated solar power (CSP) generation, hybrid automotive power generation and aerospace. Research is actively been pursued in the field of power generation using solar heat, where novel thermodynamic cycles like supercritical carbon dioxide (sCO2) Brayton and Organic Rankine Cycles are considered as superior options over conventional steam and gas turbine based cycles. The inherent feature of these cycles is high speed turbomachinery which demands a compatible high speed generator for an efficient turbo-generator power block. Switched reluctance (SR) machines are inherently advantageous for high-speed operation since the rotor is magnet free, carries no current, and can be constructed using a single material. This paper investigates the structural and rotodynamic aspects of a 5 kW, 10000 rpm, 6/4 pole switched reluctance generator. The rotor is devoid of laminations and is a single solid body. Preliminary results show that the effect of centrifugal loading on radial deflections is higher than the radial electromagnetic forces. The critical speeds are widely spaced from the desired operating speed.