| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence difficulties in high frequency current leakage in a three-phase AC equipment by suppressing a common mode voltage fluctuation itself at a load by controlling an inverter by two-arm-on switching. SOLUTION: Three-phase AC is generated by alternately repeating a switching control (two-arm-on switching) in which an upper arm of a certain phase is turned on, the lower arm of the other phase is turned on, and both the upper arm and lower arm are turned off for a remaining phase among each phase of U, V, W of a three-phase voltage type inverter 10. By doing this, a voltage of E/2 is applied to one of the phases U, V, W, and a voltage of -E/2 to one of the others, thereby resulting in uniform application of voltage as a whole so that the common mode voltage as the voltage at the virtual neutral point of delta connection load 30 is always at zero potential. Because of this, no high frequency current is generated which leaks to the outside of the load. |
