PURPOSE: To enable a PWM controller used for inverters, etc., for controlling the torque or speed of induction motors, synchronous motors, etc., to change a carrier frequency over a wide range and to make the carrier frequency suit able for the characteristic of a used switching element so that the controller can be used for various switching elements.
CONSTITUTION: In a PWM controller 20G which generates a PWM control signal PU by comparing a voltage commanding value Vuc with triangular waves CA, the triangular waves CA are generated by means of an up-down counter 32 the counting direction of which is inverted when a count value specified by a frequency setting value Fs is reached and, at the same time, the magnitude of the voltage commanding value Vuc is changed in accordance with the frequency setting value Fs.
TACHIKAWA ATSUO
ODERA NOBUYUKI
NISHIDA YOSHIHARU
YAMASHITA TOSHIRO
TAKAKADO YUZO
INOUE KENJI
SHINKO ELECTRIC CO LTD
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