Extending The Limits of Short-Stroke High Peak Force Density Solenoids

Abstract:
This paper presents a design approach to overcome the limitations of conventional pot core short-stroke solenoids with limited outer diameter that are required to operate in magnetic saturation. Starting with a conventional pot-core solenoid actuator design, the situation is analyzed to identify the limiting criteria. It is shown with an example that conventional approaches can improve the situation, but still suffer from slot leakage, especially when the potential solutions grow in axial length with the intention to reduce the peak power demand. The proposed solution changes the slot to a conical shape. While the effect on the leakage is obvious, the positive effect on the power density requires a detailed analysis which is found in a comparative multi-objective genetic optimization. The proposed design approach extends the Pareto front with respect to controllability and force density and is thus applicable as solution whenever a high power density solenoid with limiting diameter constraints is required. The paper concludes with the evaluation of an example selected from the range of optimal solutions. The main features of the new design are discussed in detail on the basis of FE simulations applied in genetic multi-criteria optimizations.