Proposal of highly effective driving method for linear oscillatory actuator

Linear oscillatory actuators (LOAs) have been widely used in linear compressors as a high-speed oscillatory driving device. Maximum efficiency is obtained at the resonance frequency determined from the spring constant and mass of the mover. However, there is a problem that the efficiency severely decreases when the driving frequency differs from the resonant frequency to change the output power. In this paper, we propose a highly effective driving method in which the thrust, which shows the characteristics of a spring, is generated by the LOA. In the proposed method, the resonance frequency always corresponds to the driving frequency. The efficiency can be improved in a wide range of driving frequency of 20-40 Hz. The efficiency is improved from 6.1 % to 52.2 % at the driving frequency of 40 Hz.