| 摘要 |
PURPOSE:To achieve a variable speed driving with a staged frequency output obtained by controlling each one of three phases obtained in a bidirectional control rectification circuit and each one opposite thereto by switching with a microcomputer. CONSTITUTION:Bidirectional control rectifiers TH are connected to respective phases of a converter 2 for 3-phase-6-phase conversion. The outputs of the control rectifiers TH are fed to a 3-phase induction motor 4 while the gate thereof is controlled with a control circuit 5. The control circuit 5 containing a microcomputer 52 provides the output thereof an alpha control circuit 54 and a sign distributor 55. The outputs thereof are subjected to an AND gate 56 with the output of a gate delay circuit 59 to generate a control signal of the control rectifiers TH. Each one of three phases and each one therto are optimally controlled by switching to obtain staged outputs. Thus, a variable speed driving can be done utilizing a.c. waveforms as intact. |
