| 摘要 |
The switching number of a bidirectional switch at an inter-sector transfer time is reduced to create a switching pattern having a lowered common mode voltage. With reference to an intermediate voltage phase of an input phase voltage of an AC-AC direct conversion circuit, a zero voltage is generated, and an input space vector is divided into twelve to determine the switching pattern of a zero-voltage vector. When an input current command vector transfers between the sectors of the space vector on the input side or when an output voltage command vector transfers between the sectors of the space vector on the output side, the bidirectional switch is switched for each phase. The degree of freedom of the combination of the zero-voltage vectors is used to change a switching table. In a steady running state, the space vector sector of a next transfer target is predicted within five patterns, and the patterns are so changed as can prevent the simultaneous switching of two phases or more. When the simultaneous switching of two phases or more is made at a duty updating timing, the duty updating is postponed at that instant and is done in a next different switch state. |
