초록 ▼

In a DC motor control system, switching element driving circuits are connected to respective base circuits of four switching elements arranged to form a bridge circuit which has a DC motor connected thereto as an electric load thereon, and an output signal interlocking circuit is provided in each pa

In a DC motor control system, switching element driving circuits are connected to respective base circuits of four switching elements arranged to form a bridge circuit which has a DC motor connected thereto as an electric load thereon, and an output signal interlocking circuit is provided in each paired driving circuits associated with the corresponding paired switching elements which are connected in series across a DC power source, respectively, thereby preventing simultaneous conduction of each paired switching elements. By virtue of the provision of the output signal interlocking circuits, it is possible to realize a PWM control system for DC motors with a simplified circuit construction and yet to thereby prevent power source short-circuiting trouble with elevated safety and reliability.

대표청구항 ▼

A DC motor control system comprising: a DC motor; a bridge circuit which is constituted by first, second, third and fourth switching elements and which is fed by a DC power source and has said DC motor connected thereto as an electric load thereon; a speed sensor for sensing a rotational speed of sa

A DC motor control system comprising: a DC motor; a bridge circuit which is constituted by first, second, third and fourth switching elements and which is fed by a DC power source and has said DC motor connected thereto as an electric load thereon; a speed sensor for sensing a rotational speed of said DC motor; a current sensor for sensing an electric current flowing through said DC motor; a triangular waveform generator for generating a triangular waveform signal; an adder for adding the triangular waveform signal to a control signal obtained on the basis of an externally applied speed command signal and negative feedback signals supplied from said speed sensor and said current sensor; a subtractor for subtracting the triangular waveform signal from the control signal; a first comparator for generating an output signal when an output signal of said adder, which is applied to said first comparator, is at a level lower than zero volt; a second comparator for generating an output signal when an output signal of said subtractor, which is applied to said second comparator, is at a level higher than zero volt; first and second driving circuits to which the output signal of said first comparator and an inverted signal thereof are applied respectively through an interface circuit; and third and fourth driving circuits to which the output signal of said second comparator and an inverted signal thereof are applied respectively through said interface circuit, said first and second driving circuits and said third and fourth driving circuits being provided with respective output signal interlocking circuits, whereby said third and fourth switching elements connected in series across said DC power source are driven by said first and second driving circuits, respectively, and said first and second switching elements connected in series across said DC power source are driven by said third and fourth driving circuits, respectively.