An innovative method of semi-active vibration suppression based on an energy-recycling approach using piezoelectric transducers is described. Piezoelectric transducers attached to or embedded in structures can convert the mechanical energy of the structure into electrical energy or, conversely, electrical energy into mechanical energy. Conventional methods have focused on how to effectively dissipate the transferred electrical energy. With our new energy-recycling method, the electrical energy is stored in the transducer functioning as a capacitor and is reused to suppress vibration of the structure, instead of simply being dissipated. This paper presents an advanced energy-recycling method to suppress multiple-mode vibration of beam structures with multiple transducers. Several control strategies based on active control theories are derived from formulae on the dynamics of a beam structure with piezoelectric transducers and electricity. We demonstrate the ability to suppress not only transient vibrations but also vibrations excited by sinusoidal and random forces.