| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately correct strain while keeping high-speed response, concerning the strain correction of the output voltage of an inverter by a rectifier load. <P>SOLUTION: A strain correcting controller 9 corrects its strain, based on the deviation between the output voltage of the inverter and the product (a normal voltage instantaneous value) of a voltage command Vref and sin(θ) computed by a phase detected value θ. A discrete Fourier transformer 21 and an inverse discrete Fourier transformer 22 extract main harmonics such as fifth order, seventh order, etc. contained in an inverter output voltage signal, etc., and a deviation accumulating means 25 accumulates the harmonics as the amount of voltage strain, and a limiter 24 limits the accumulated value of the amount of voltage strain to the upper limit value and the lower limit value and adds it to the output voltage command of an inverter. It gets the three-phase full wave rectified voltage of the output voltage of the inverter or the root-mean-square value by dq conversion, and when these get over their thresholds, it sets the upper limit value and the lower limit value of the limiter to zero thereby resetting the accumulated value once. <P>COPYRIGHT: (C)2008,JPO&INPIT |
