| 摘要 |
PROBLEM TO BE SOLVED: To reduce voltage distortion due to a harmonic voltage and a dead time generated when it is connected to a direct current load having a rectifier.SOLUTION: An output voltage value of an alternating current filter 20 is three-phase or two-phase converted and rotation-coordinate converted, so as to generate a conversion voltage value (102, 103). A differential value of the conversion voltage value and an output voltage reference value is gain-multiplied so as to calculate first and second gain adjustment values (107). The adjustment values are rotation-coordinate converted at frequencies of 6 times and -6 times of a basic frequency, so as to generate first and second values (108, 109). The values are integrated so as to calculate first and second integrated values (110), and the integrated values are rotation-coordinate inverse-converted at the 6 times and -6 times frequencies, so as to generate first and second inverse conversion values (111, 112). A value found by feedback controlling the error between the inverse conversion values and the output voltage reference value of the conversion voltage value is added to calculate a voltage command value (113). A value found by rotation-coordinate converting and two-phase or three-phase converting the command value is used as an output voltage command value of an inverter 10 (114, 115). |
