A novel theory of the commutating process of half/bridge thyristor are welding inverter is presented. According to the characteristic of its typical primary current pulse, a commutating process can be divided into th...A novel theory of the commutating process of half/bridge thyristor are welding inverter is presented. According to the characteristic of its typical primary current pulse, a commutating process can be divided into three stages. ie.. front-edge wave-head stage and back-edge stage.The equivalent circuits of each stage are presented respectively. For wave-head stage, the differential equation about the voltage across commutating capacitor has been set up with the initial condition of nonzero-current and nonzero-voltage. and its solutions are completely in accord with the practically measured waveforms. For front and back edge stages, the theory of current shifting on constant magnetic condition is introduced. The process, in which the inverse voltage across commutating capacitor is formed, and the rule, according to which the inverse voltage varies.are discussed. In addition. each. special operating state is studied carefully and a reasonable design state is determined. By T-type equivalent circuit in the design. state. the fundamental formulas for accurate engineering design are derived. Finally. two design cases are given.展开更多
文摘A novel theory of the commutating process of half/bridge thyristor are welding inverter is presented. According to the characteristic of its typical primary current pulse, a commutating process can be divided into three stages. ie.. front-edge wave-head stage and back-edge stage.The equivalent circuits of each stage are presented respectively. For wave-head stage, the differential equation about the voltage across commutating capacitor has been set up with the initial condition of nonzero-current and nonzero-voltage. and its solutions are completely in accord with the practically measured waveforms. For front and back edge stages, the theory of current shifting on constant magnetic condition is introduced. The process, in which the inverse voltage across commutating capacitor is formed, and the rule, according to which the inverse voltage varies.are discussed. In addition. each. special operating state is studied carefully and a reasonable design state is determined. By T-type equivalent circuit in the design. state. the fundamental formulas for accurate engineering design are derived. Finally. two design cases are given.
