Summary: The semi-active energy-recycling methods studied in this article suppress vibration by controlling switches in inductive shunt circuits connected to piezoelectric transducers in vibrating structures. This article compares the performances of simple and sophisticated methods that can be used for multiple-mode vibration. Although it should be obvious that the performance of the latter is superior, we need to know whether the superior performance of the sophisticated method justifies the expense incurred by its complexity. The performance comparisons were done by numerically simulating the vibration suppression of a truss structure with a piezoelectric transducer. We simulated transient free vibrations, forced sinusoidal vibrations, and forced random vibrations. In all cases, both methods were shown to be effective for the first and second modes of vibration. The ways and situations in which the sophisticated method is superior to the simple method were also elucidated. A vibration suppression experiment using a truss was also carried out and demonstrated that the sophisticated method worked well under random excitation.