| 摘要 |
PROBLEM TO BE SOLVED: To improve the accuracy of following performance and the suppression of a current distortion rate by measuring a current change rate due to the opening and closing of a switching element, measuring the inductance of a reactor, and using the inductance for controlling. SOLUTION: The switching-control device of a converter is composed of a three-phase voltage-mode converter bridge 1, a polyphase AC power supply 2, an AC reactor 3, an AC controller 4, a DC controller 5, and an inductance computing element 6. In this case, upper and lower arms are off and on, respectively, in one phase with an arbitrary control timing, and the upper and lower arms are set on and off, respectively, in the next control cycle. Meanwhile, no switching is made in other phases. At this time, based on the detection values of a power current and DC and AC voltages at each control timing, the value of L (inductance) which is inserted into a power supply is obtained according to an equation L=(Vs-2Vd)T/ is(tn)-is(tn+1)}, where T, Vs and 'is', and Vd are control cycle, power voltage and current of a phase under noticed, and DC voltage, respectively.
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