Transient-free commutation of a resonant-mode array of inductors

A method and system are proposed for a transient-free commutation of a resonant-mode array of inductors. A single capacitor is used to tune the entire array, and triacs are used to commutate the inductors. To avoid the transients, the tuning capacitor is electrically locked when it stores the whole energy of the excited circuit. This prevents the capacitor from discharge during the fast, 0.1 ms delays, where a triac disconnects the previously excited inductor and another triac connects the next inductor in series with the capacitor. The 0.1 ms delays are defined by the triacs' recovery time. After completing the commutation, the fully charged tuning capacitor is unlocked, and the next excitation cycle begins with no transient. We neglect the short recovery delays and regard the commutation process as transient free. We also show that the recovery delays can further be reduced if the triacs are replaced with faster switching devices. Our experiments with an array of 64 inductors prove the efficiency and simplicity of the commutation method and system. The approach suggested can be useful in instrumentation, power and control magnetics, where a large number of resonant-mode inductors should be quickly commutated.