Direct Method for Evaluation of Energy Conversion Efficiency in Solenoid Valves During Start Transient and Improvements Obtained by Core Annealing

Energy conversion efficiency in solenoid valves is an important subject of study considering the wide usage and application of such valves in the industry. In this paper we have attempted to present an analytical multi-physics-based formulation which will help in deducing the energy conversion efficiency of solenoid valves in a direct manner without loss apportionment. We call this method as the 'flux augmentation method'. The effect of opposing load, applied voltage and core annealing on energy conversion efficiency are studied. The electromechanical transient characteristics (ETC) during valve opening is the focus of this study and analysis. It is found that there exists an optimum voltage of operation at which the efficiency is at its highest. This optimum voltage of operation varies with actuator load. A maximum energy conversion efficiency of 38.6 % is noticed for the range under study and a maximum improvement of 9 % could be obtained by annealing the soft magnetic core material. The valve should ideally be operated at the point of maximum energy conversion efficiency in order to be more efficient in the long run over its life span while operating in pulse width modulation mode.