Electric valve control device, electric valve device, and method for controlling electric valve

An electric valve control device for controlling an electric valve that includes a valve body including a valve seat, a rotor rotatable with respect to the valve body, a stator constituting a stepping motor together with the rotor, a valve member facing the valve seat and moving toward the valve seat when the rotor rotates in a first direction, and a stopper mechanism restricting rotation of the rotor in the first direction when the rotor is at a reference position, the electric valve control device comprising:

• a rotation controller configured to input a pulse to the stepping motor to rotate the rotor in the first direction;
• a current obtainer configured to obtain a current generated in the stator by the rotation of the rotor;
• and
• a state determiner configured to determine whether the electric valve is in a first-rotation restricted state where the rotation of the rotor in the first direction is restricted, based on a degree of difference between a waveform of the current and a reference waveform of the current.

A method for controlling an electric valve that includes a valve body including a valve seat, a rotor rotatable with respect to the valve body, a stator constituting a stepping motor together with the rotor, a valve member facing the valve seat and moving toward the valve seat when the rotor rotates in a first direction, and a stopper mechanism restricting rotation of the rotor in the first direction when the rotor is at a reference position, the method comprising:

• inputting a pulse to the stepping motor to rotate the rotor in the first direction;
• obtaining a voltage generated in the stator by the rotation of the rotor;
• and
• determining whether the electric valve is in a first-rotation restricted state where the rotation of the rotor in the first direction is restricted, based on a degree of difference between a waveform of the voltage and a reference waveform of the voltage.

A method for controlling an electric valve that includes a valve body including a valve seat, a rotor rotatable with respect to the valve body, a stator constituting a stepping motor together with the rotor, a valve member facing the valve seat and moving toward the valve seat when the rotor rotates in a first direction, and

• a stopper mechanism restricting rotation of the rotor in the first direction when the rotor is at a reference position, the method comprising:
• inputting a pulse to the stepping motor to rotate the rotor in the first direction;
• obtaining a current generated in the stator by the rotation of the rotor;
• and
• determining whether the electric valve is in a first-rotation restricted state where the rotation of the rotor in the first direction is restricted, based on a degree of difference between a waveform of the current and a reference waveform of the current.