Study on the vibration characteristics induced by magnetic force on air-core reactors

Air-core reactors are critical components in power electronic systems, particularly in HVDC and harmonic filtering applications. However, their operation under harmonic currents induces electromagnetic forces that generate mechanical vibrations, leading to potential noise issues, structural fatigue, and reduced efficiency. This paper investigates the vibration characteristics of air-core reactors induced by magnetic forces, focusing on the frequency-dependent vibration distribution. The study begins with a theoretical analysis of electromagnetic force generation, showing that the magnetic force is proportional to the square of the current and varies with frequency. A controlled experimental setup is designed, featuring programmable harmonic current sources and non-contact laser vibrometers, to measure vibration responses across the reactor’s surface under single-frequency excitations ranging from 25 Hz to 650 Hz. Amplitude and phase distributions are mapped on the reactor’s cylindrical surface, revealing distinct patterns influenced by frequency. At lower frequencies, vibration distributions exhibit broad longitudinal patterns with circumferential variations, while higher frequencies produce block-like segmentations with alternating peaks and troughs. The results highlight the significant role of structural components, such as star frames, in shaping vibration characteristics. These findings provide critical insights for optimizing reactor design, mitigating noise, and improving reliability. This study offers a comprehensive framework for analyzing the complex interplay between magnetic forces and mechanical vibrations in air-core reactors, contributing to enhanced performance and predictive maintenance strategies in power electronic systems.