| 摘要 |
PURPOSE:To allow a phase current to approach a sine wave by a method wherein a value in a threshold signal transmitter is set in such a way that it can be variable in order to limit the phase current to a smaller threshold value within the area of a low frequency or speed, and to a greater threshold value within the area of a medium or high speed. CONSTITUTION:A threshold signal transmitter in the converting circuit (current target value phase current target value) of the power supply unit of a motor, contains a setter 41, multiplier 42 which multiplies the value B0 preset by the setter by a variable coefficient k, a function generator 43 which receives an input signal corresponding to the speed (n) of revolution of a motor or a power supply frequency (f) and generates a function output signal (k) having the specified functional relation with this input signal, and an inversion amplifier 44. Then, the positive threshold value +B=kB0 is outputted from the multiplier 42, while the negative threshold value -B-kB0 is outputted from the inversion amplifier 44. Therefore, the current is allowed to approach a sine wave current by fully utilizing the capacity that a power converting unit has in the area of medium and high speeds. |
