<p>➀ Cycloconverters are AC-to-AC power converters that adjust frequency without intermediate DC conversion, primarily used for controlling low-speed, high-torque motors in industrial applications; </p><p>➁ They operate by modulating thyristors to reconstruct output waveforms, with types including step-down, single/three-phase configurations, and blocking/circulating current modes; </p><p>➂ Key applications include steel mills, marine propulsion, and heavy machinery, offering high efficiency (95-98%) but facing challenges like harmonic distortion and complex control systems.</p>