摘要: Besides the ability to change frequency and amplitude of output voltages a high-performance changer (FC) should produce sinusoidal in-phase input currents allow bidirectional power flow. The Venturini FC meets all these requirements but has some deficiencies which affect its practicality. Three kinds improved FC's?a new direct special applications, current source FC, voltage indirect FC?which retain good features Venturini's overcome are investigated. Their principles, features, problems discussed. New control laws circuits proposed.