Smart Electric Valve Controller Based on All Digital Phase-Locked Loop

Electric valve has been applied to various occasions and domains. In some adverse environments where such defects of traditional control system as low efficiency and poor safety have been exposed, optical encoder is adopted to detect the motor’s angular speed and displacement and ADPLL is used for generating control logic, so as to regulate switching frequency and duty ratio of pulse wavelength modulation (PWM), alter the motor’s input voltage and current and achieve the open and close control of Electric valve. The system can automatically regulate the rotating speed and the dragging torque of motor based on the open and close position, rotating speed and torque of the valve to make sure that the motor can achieve the best rotating speed and torque. The results of the test by motor 90ZY24-200 prove that the system has prompt response, high accuracy, little harmonic and ripple range; it can also automatically adapt to the torque alteration to realize the protective function of direct current (DC) motor. Electric valve control based on ADPLL can not only realize functions of the whole system, but also enjoys a stable and reliable performance. It can reduce the harmonic and ripple, and help the whole system achieve real-time remote control, data collection and transmission, and display the motor torque in LED, so as to control the valve flow stably and accurately through DC motor.