Pulse width-modulation control device for invertor devices

摘要

A pulse width-modulation control device includes a superposed signal creating circuit for superposing a sine wave signal having a predetermined frequency upon a triangular wave signal as a carrier signal, having a frequency higher than the predetermined frequency to form a superposed signal. A pulse width modulating circuit compares the superposed signal with a predetermined threshold level to form a pulse width modulated signal. A pulse width limiting circuit limits the pulse width of the pulse width modulated signal when the pulse width modulated signal has a pulse width lying outside a predetermined range, and supplies a pulse signal having a pulse width thus limited to a switching device.