| 摘要 |
PROBLEM TO BE SOLVED: To keep a harmonic element included in primary current at the lowest level all the time, by detecting unbalancing of the secondary winding of a transformer from the phase of modulated wave which is required for generating a PWM pulse supplied to a plurality of converter devices, and controlling a carrier phase according to it. SOLUTION: An AC stringing 1 is connected to the primary winding 2 of a transformer, and secondary windings 3, 4 are connected to converter devices 9, 10 respectively. Corresponding PWM signals Spwm1, Spwm2 are outputted to the converter devices 9, 10 based on secondary current Is1, Is2 detected by the current detectors 5, 6, Is1* and Is2* from a host controller, and synchronization signal Sn whose secondary voltage Es1 detected by a voltage detector 7 is converted by a synchronization signal generation means 8, and according to these, a carrier phase is controlled. It is thus possible to keep a harmonic element included in primary current at the lowest level. |
