Half-bridge power-processing cell utilizing a linear variable inductor and thyristor-dual switches

Bridge-type power-processing cells using linear variable inductors (LVIs) as controlled elements are inherently reactive; during certain portion of the switching cycle they restore energy to the source. The switches turn on a zero current, and can use the thyristor-dual principle to virtually eliminate turn-off losses, an inherent advantage of the LVI topologies being a constant-frequency operation. A half-bridge LVI power-processing cell utilizing thyristor-dual switches is analyzed, its properties are discussed, and experimental results illustrating these properties are reported. It is demonstrated that the implementation is feasible and that it results in extremely low switching losses. The transient-stability problem inherent in topologies with thyristor-duals is discussed, and a simple and highly reliable solution is proposed. Steady-state analysis has been carried out, and the boundary of the fail-safe commutation of the switches is determined. The numerical results obtained can be directly incorporated into straightforward design programs; the design procedure is summarized in a comprehensive flowchart.