| 摘要 |
PURPOSE:To improve an input power factor in a low-speed operation region, and to conduct operation up to a high-speed operation region without distorting output voltage by continuously transferring the output voltage references of each converter smoothly from asymmetric control to symmetric control. CONSTITUTION:Actual speed omegagamma and certain low-frequency operation speed omegaalphaand high-speed frequency operation speed (omegabeta) are compared. Frequency is set at frequency omegaalpha getting no trouble through asymmetric control in the distortion of the output voltage waveform of a cycloconverter and high-speed operation frequency omegabeta incapable of being applied as a system by the effect of the distortion, etc., of the output voltage waveform when symmetric control is not executed. Consequently, asymmetric control is conducted in the region of ¦omegagamma¦<=omegaalpha, and symmetric control is performed in the region of ¦omegagamma¦>=omegabeta. Volt age references EU1S, EU2S are determined in order to continuously transfer output voltage at each stage smoothly from asymmetic control to symmetric control in the speed range of the regions of omegaalpha<=omegagamma<=omegabeta. |
