| 摘要 |
PURPOSE:To prevent increase of the weight and volume of an inverter controller by controlling an inverter with a decrease/increase signal if an AC current is excessive/insufficient when the AC current taken from a stringing is converted into a DC current and then further inverted into an AC current through the inverter. CONSTITUTION:AC voltages taken from a stringing 1 is transformed through a transformer 2 and fed to CTs 15A, 15B to obtain currents IS1, IS2 to be fed to converters 4A, 4B. Absolute value circuits 16A, 16B then amplify the absolute values of the currents IS1, IS2 and a larger one is selected 17 and smoothed 18 to obtain an average value ISM. Comparators 19A, 19B compare the current ISM with preset reference values A, B(A>B). If ISM>A or ISM<B, the current ISM is fed to DN or UP terminal of a motor current command signal regulator 20 to regulate a maximum current command signal IMO at terminal U of the regulator 20 and a zero command signal at terminal L thus delivering a command signal IM to an inverter 6. According to the constitution, highly reliable control is realized without increasing the volume or the weight of the inverter controller. |
