Three distinct synchronized switching circuits based on a magnetostrictive actuator are compared in this paper to examine their control mechanisms and circuit characteristics. These circuits include a semi-active shunt circuit, a semi-active current inversion and amplification circuit, and a semi-active automatic current inversion and amplification circuit. Each circuit type employs an additional electronic switch. The synchronized switching method enables the rational control of the circuit current generated by the magnetostrictive actuator to fulfill any desired control strategy. Simulation and experimental results on a 10-bay truss structure reveal that the three circuits can effectively adjust the polarity of the induced current as needed. The three circuits are then compared to thoroughly analyze their unique characteristics and explain their respective advantages and dis-advantages. Using the comparison results, various options available for control circuit design are demonstrated.

When attempting to suppress structural vibrations employing a magnetostrictive transducer, owing to the control force is generated from current, a larger amplification of the current entails superior control performance. The semi-active control theory uses the synchronized switching damping (SSD) technique for structural vibration suppression while requiring a minimal energy supply. However, the absence of external energy input limits the current amplification performance. To address this limitation, this study proposes a novel method that combines semi-active vibration suppression method with negative capacitance to improve the current amplification performance. The proposed circuit switches the circuit status between shunt, inductor-capacitor (LC) electrical oscillation, and negative capacitance circuits. A mathematical model was employed to analyze the current operation, suppression performance, and robustness of the proposed circuit. Further, machine learning and kernel regression model were employed to predict the optimal control force gain. Validation experiments conducted on a 10-bay truss structure identical to the simulation model show that the experimental results align with the simulation predictions. The vibration suppression rates of the proposed method under single-mode and multiple-mode vibrations reached 85.8% and 78.3%, respectively, which are 2.64 and 1.89 times higher than those achieved by conventional methods.

Vibration energy harvesting (VEH) has garnered substantial attention in recent years. Among the various VEH technologies, magnetostrictive transducers stand out due to their remarkable resistance to shock and heat. This study presents a novel magnetostrictive VEH method that integrates an innovative circuit design with a switching control strategy to optimise energy harvesting. The proposed configuration comprises a magnetostrictive transducer, an electrical circuit, and an electronic switch. The design minimises energy losses and improves overall harvesting efficiency by utilising fewer diodes than conventional circuits. The switching control strategy regulates the electronic switch’s operation in response to multimodal vibrations. Numerical simulations were performed to evaluate the system’s performance and investigate how changes in transducer and circuit parameters affect the harvested energy. Experimental validation on a truss structure showed that the proposed method harvested 105 times more energy than traditional techniques.