DRIVE-CONTROL DEVICE FOR MOTOR FOR PUMP

PROBLEM TO BE SOLVED: To provide a drive-control device for a motor for a pump, which can make a control resolution in the vicinity of the rated point of the pump and can identically decide a command analog signal from the objective output of a pump by laying the analog signal and the pump output in substantially a linear relation, and is superior in responsiveness as compared to general PID control. SOLUTION: This drive control device is equipped with a pressure detector 108 or a flow detector which detects the pressure or flow rate of the pump and outputs a detection signal, and a pressure control part 109 or a flow control part which receives the detection signal, generates an analog signal for deciding the pulse width of PWM and controls pressure into set objective pressure or flow rate into objective flow rate, and a PWM signal generating circuit 111 has a sine wave generating circuit 112 which generates the sine wave signal of a frequency corresponding to the carrier frequency of PWM, an absolute value generating circuit 113 which generates the absolute value signal of the sine wave signal, and a comparison circuit 114 which compares the analog signal with the absolute value signal.