Motor-operated valve control device, motor-operated valve device, and motor-operated valve state determination method

Abstract

[Problem] To provide an electric valve control device capable of determining at an appropriate timing whether or not the rotation of the rotor of a stepping motor is restricted, an electric valve device having the electric valve control device, and an electric valve state determination method. [Solution] A drive current for rotating a rotor 41, the drive current being controlled by a pulse width modulation method, is supplied to a coil of a stator 60 of a stepping motor 66. A low-pass filter of an electric valve control device 70 has a cutoff frequency lower than a pulse width modulation frequency used in the pulse width modulation method and allows a voltage component having a frequency lower than the cutoff frequency of a voltage generated in the coil to pass. A computer of the electric valve control device 70 determines, using a voltage component that has passed through the low-pass filter, whether or not an electric valve 5 is in a rotation-restricted state in which the rotation of the rotor 41 is restricted.

Description

[Technical Field]

[0001] The present invention relates to an electric valve control device, an electric valve device having the electric valve control device, and a method for determining the state of an electric valve. [Background technology]

[0002] Patent Document 1 discloses an example of a conventional motor-operated valve. The motor-operated valve is incorporated, for example, in the refrigeration cycle system of an air conditioner. The motor-operated valve has a valve body, a valve element, and a stepping motor for moving the valve element. The stepping motor has a rotor and a stator. The stator has a coil. When a pulse is input to the stepping motor, the rotor rotates. Specifically, the rotor rotates when a drive current corresponding to the pulse is supplied to the stator of the stepping motor. The valve element moves in response to the rotation of the rotor. When the rotor is in a reference position, a movable stopper that rotates together with the rotor abuts against a fixed stopper fixed to the valve body, restricting the rotation of the rotor in a first direction.

[0003] The motor-operated valve is controlled by a motor-operated valve control device. In an initialization operation, the motor-operated valve control device inputs pulses to the stepping motor to rotate the rotor in a first direction and position the rotor at a reference position. The number of pulses input to the stepping motor is a number sufficient for the movable stopper to abut against the fixed stopper (hereinafter referred to as the "initialization number"). When the rotor rotates in the first direction and the movable stopper abuts against the fixed stopper, the rotor is positioned at the reference position.

[0004] The motor-operated valve control device inputs pulses to the stepping motor until the number of pulses input to the stepping motor reaches the initialization number. As a result, the motor-operated valve control device may input pulses even after the rotor is positioned at the reference position, which makes the initialization operation take a long time. Furthermore, if pulses are input to the stepping motor after the rotor is positioned at the reference position, the movable stopper repeatedly collides with the fixed stopper, generating noise. In particular, if the rotor's position immediately before the initialization operation is close to the reference position, noise will be generated for a long time.

[0005] During the initialization operation, the waveform of the voltage generated in the stator by the rotation of the rotor (the voltage electromagnetically induced in the stator) differs before and after the rotation of the rotor is restricted. The motor-operated valve control device disclosed in Patent Document 2 acquires the voltage generated in the stator by the rotation of the rotor and determines whether the rotation of the rotor in a first direction is restricted based on the degree of difference between the voltage waveform and a reference voltage waveform. When it determines that the rotation of the rotor in the first direction is restricted, the motor-operated valve control device stops the rotation of the rotor. In this way, the motor-operated valve control device stops the rotation of the rotor immediately after the rotor is positioned at the reference position, thereby preventing noise from being generated for a long period of time. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2019 / 130928 [Patent Document 2] Patent No. 7254400 Summary of the Invention [Problem to be solved by the invention]

[0007] The stator has an A-phase stator and a B-phase stator. When a drive current is supplied to both the A-phase stator and the B-phase stator, the voltage generated in the A-phase stator includes a voltage component generated by the drive current and a voltage component generated by the rotor rotation. The voltage generated in the B-phase stator also includes a voltage component generated by the drive current and a voltage component generated by the rotor rotation. In a configuration in which the drive current is controlled using pulse width modulation, the frequency and amplitude of the voltage component generated by the drive current are relatively high, and the voltage component generated by the rotor rotation is hidden by the voltage component generated by the drive current.

[0008] Therefore, the motor-operated valve control device of Patent Document 2 determines whether rotation of the rotor in the first direction is restricted when a drive current is supplied to only one of the A-phase stator and the B-phase stator, based on the voltage generated in the other stator to which no drive current is supplied. The motor-operated valve control device cannot determine whether rotation of the rotor in the first direction is restricted when drive current is supplied to both the A-phase stator and the B-phase stator. Therefore, the motor-operated valve control device may not be able to determine when rotation of the rotor in the first direction is actually restricted.

[0009] Therefore, an object of the present invention is to provide an electric valve control device that can determine at an appropriate time whether the rotation of the rotor of a stepping motor is restricted, an electric valve device having an electric valve control device, and a method for determining the state of an electric valve. [Means for solving the problem]

[0010] In order to achieve the above object, one aspect of the present invention provides an electric valve control device that controls an electric valve having a valve body with a valve port, a stepping motor with a rotor and a stator, and a valve body that moves relative to the valve port when the rotor rotates, the electric valve control device having a low-pass filter and a processing device, a drive current for rotating the rotor controlled by a pulse width modulation method is supplied to the coil of the stator, the low-pass filter has a cut-off frequency lower than the pulse width modulation frequency used in the pulse width modulation method and passes voltage components of frequencies lower than the cut-off frequency in the voltage generated in the coil, and the processing device uses the voltage component that has passed through the low-pass filter to determine whether the electric valve is in a rotation restricted state in which rotation of the rotor is restricted.

[0011] In the present invention, it is preferable that the processing device determines whether the motor-operated valve is in the rotation restricted state based on the degree of difference between the waveform of the voltage component and a reference waveform of the voltage component.

[0012] In the present invention, it is preferable that a motor driver is connected to the coil, and when a plurality of pulses having consecutive numbers are input to the motor driver in a repeated sequence, the motor driver supplies the drive current corresponding to the plurality of pulses to the coil to rotate the rotor, and the processing device starts inputting the plurality of pulses to the motor driver, acquires the voltage component when the drive current corresponding to the pulse input to the motor driver (hereinafter referred to as the "pulse to be determined") is supplied to the coil, determines whether the motor-operated valve is in the rotation restriction state using the voltage component, and if it determines that the motor-operated valve is in the rotation restriction state, stops inputting the plurality of pulses before inputting the next pulse of the pulse to be determined.

[0013] In the present invention, it is preferable that a motor driver is connected to the coil, and when a plurality of pulses having consecutive numbers are input repeatedly to the motor driver in sequence, the motor driver supplies the drive current corresponding to the plurality of pulses to the coil to rotate the rotor, and the processing device starts inputting the plurality of pulses to the motor driver, acquires the voltage component when the drive current corresponding to the pulse input to the motor driver (hereinafter referred to as the "pulse to be determined") is supplied to the coil, determines whether the motor-operated valve is in the rotation restriction state using the voltage component during the input period of the next pulse after the pulse to be determined, and if it is determined that the motor-operated valve is in the rotation restriction state, inputs a pulse having the same number as the pulse to be determined to the motor driver following the next pulse after the pulse to be determined, and stops inputting the plurality of pulses.

[0014] In the present invention, it is preferable that a motor driver is connected to the coil, and when a plurality of pulses having consecutive numbers are input to the motor driver in a repeated sequence, the motor driver supplies the coil with the drive current corresponding to the plurality of pulses to rotate the rotor, and the processing device starts inputting the plurality of pulses to the motor driver, acquires the voltage component when the drive current corresponding to the pulse input to the motor driver (hereinafter referred to as the "pulse to be determined") is supplied to the coil, and determines whether the motor-operated valve is in the rotation restriction state using the voltage component during the input period of the pulse next to the pulse to be determined, and if it is determined that the motor-operated valve is in the rotation restriction state, inputs the plurality of pulses to the motor driver in a sequence following the pulse next to the pulse to be determined until a pulse having the same number as the pulse to be determined is input to the motor driver, and then stops inputting the plurality of pulses.

[0015] In the present invention, it is preferable that the cutoff frequency is set based on the pulse width modulation frequency.

[0016] In order to achieve the above object, a motor-operated valve device according to another aspect of the present invention includes the motor-operated valve and the motor-operated valve control device.

[0017] In order to achieve the above object, another aspect of the present invention provides a state determination method for an electrically operated valve having a valve body with a valve port, a stepping motor with a rotor and a stator, and a valve body that moves relative to the valve port when the rotor rotates, the method comprising: supplying a drive current for rotating the rotor, which is controlled by a pulse width modulation method, to the coil of the stator; inputting the voltage generated in the coil to a low-pass filter that has a cut-off frequency lower than the pulse width modulation frequency used in the pulse width modulation method and that passes voltage components of the voltage generated in the coil that have a frequency lower than the cut-off frequency; and using the voltage component that has passed through the low-pass filter, determining whether the electrically operated valve is in a rotation restricted state in which rotation of the rotor is restricted. [Effects of the Invention]

[0018] According to the present invention, a stepping motor has a rotor and a stator, and a drive current controlled by pulse width modulation is supplied to the stator coil to rotate the rotor. Then, a voltage component with a frequency lower than the cutoff frequency in the voltage generated in the coil is used to determine whether the motor-operated valve is in a rotation-restricted state in which rotor rotation is restricted. This configuration makes it possible to remove the relatively high-frequency voltage component generated by the drive current from the voltage generated in the coil, thereby preventing the voltage component generated by rotor rotation from being obscured by the voltage component generated by the drive current. This makes it possible to determine whether the motor-operated valve is in a rotation-restricted state based on the voltage generated in the coil, even if a drive current is supplied to the coil. Therefore, it is possible to determine at an appropriate time whether the rotor rotation of the stepping motor is restricted. [Brief explanation of the drawings]

[0019] [Figure 1]1 is a block diagram of an air conditioning system having an electric valve device. [Figure 2] FIG. 2 is a cross-sectional view of the motor-operated valve device. [Figure 3] FIG. 2 is a view showing a valve stem holder of the motor-operated valve device. [Figure 4] FIG. 4 is a side view of a guide bush of the motor-operated valve device. [Figure 5] 10A and 10B are diagrams illustrating a stopper member of the motor-operated valve device. [Figure 6] FIG. 2 is a plan view of a valve stem holder, a stopper member, a rotor, and a stator of the motor-operated valve device. [Figure 7] FIG. 2 is a diagram showing a computer, a motor driver, a low-pass filter, and a stepping motor included in an electric valve control device of the electric valve device. [Figure 8] 10A and 10B are diagrams illustrating an example of the relationship between step signals and direction signals input to a motor driver and pulses input to a stepping motor. [Figure 9] 10 is a diagram illustrating an example of a correspondence relationship between a pulse and an A-phase current target value and a B-phase current target value. FIG. [Figure 10] 4A and 4B are diagrams illustrating examples of waveforms of an A-phase current and a B-phase current. [Figure 11] FIG. 2 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[1] is input). [Figure 12] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[2] is input). [Figure 13] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[3] is input). [Figure 14] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[4] is input). [Figure 15] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[5] is input). [Figure 16] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[6] is input). [Figure 17] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[7] is input). [Figure 18] FIG. 10 is a diagram showing a schematic diagram of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[8] is input). [Figure 19] FIG. 10 is a diagram showing an example of a waveform of a voltage generated in a coil of a stator. [Figure 20] 20 is a diagram showing an example of the waveform of a voltage component having a frequency lower than the cutoff frequency in the voltage shown in FIG. 19. FIG. [Figure 21] FIG. 10 is a diagram showing an example of the waveform of a voltage component having a frequency lower than the cutoff frequency in the voltage generated in the stator coil (a state in which the rotor is allowed to rotate). [Figure 22] FIG. 10 is a diagram showing an example of the waveform of a voltage component having a frequency lower than the cutoff frequency in the voltage generated in the coil of the stator (in a state in which the rotation of the rotor is restricted). [Figure 23] FIG. 10 is a diagram illustrating an example of a rotation angle of a rotor. [Figure 24] 10A and 10B are diagrams comparing waveforms of voltage components at frequencies lower than the cutoff frequency in the voltage generated in the stator coil. [Figure 25] FIG. 10 is a diagram showing an example of a data table relating to a reference waveform of a voltage component at a frequency lower than the cutoff frequency in the voltage generated in the coil of the stator. [Figure 26] 10A and 10B are diagrams showing examples of the waveform of a voltage component at a frequency lower than the cutoff frequency in the voltage generated in the coil of the stator, and a reference waveform of the voltage component. [Figure 27] 4 is a flowchart showing an example of the operation of the motor-operated valve control device (Operation Example 1). [Figure 28] 6 is a flowchart showing other examples of the operation of the motor-operated valve control device (operation examples 2 and 3). [Figure 29] FIG. 10 is a diagram showing an example of the rotation angle of the rotor (microstep method 1). [Figure 30]This is a diagram comparing the waveforms of voltage components at frequencies lower than the cutoff frequency in the voltage generated in the stator coil (microstep method 1). [Figure 31] FIG. 10 is a diagram showing an example of the rotation angle of the rotor (microstep method 2). [Figure 32] This is a diagram comparing the waveforms of voltage components at frequencies lower than the cutoff frequency in the voltage generated in the stator coil (microstep method 2). DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a motor-operated valve device according to one embodiment of the present invention will be described with reference to FIGS.

[0021] FIG. 1 is a block diagram of an air conditioning system having a motor-operated valve device. FIG. 2 is a cross-sectional view of the motor-operated valve device. FIG. 3 is a diagram showing a valve stem holder of the motor-operated valve device. FIG. 3A is a perspective view of the valve stem holder, and FIG. 3B is a plan view of the valve stem holder. FIG. 4 is a side view of a guide bush of the motor-operated valve device. FIG. 5 is a diagram showing a stopper member of the motor-operated valve device. FIG. 5A is a perspective view of the stopper member, and FIG. 5B is a plan view of the stopper member. FIG. 6 is a plan view of the valve stem holder, stopper member, rotor, and stator of the motor-operated valve device. FIG. 6 schematically shows the rotor magnetic poles and stator. FIG. 7 is a diagram showing the computer, motor driver, low-pass filter, and stepping motor included in the motor-operated valve control device of the motor-operated valve device. FIG. 8 is a diagram showing an example of the relationship between the step signal and direction signal input to the motor driver and the pulses input to the stepping motor (motor driver). FIG. 9 is a diagram showing an example of the correspondence between the pulses and the A-phase current target value and the B-phase current target value. Fig. 10 is a diagram showing an example of the waveform of the A-phase current and the waveform of the B-phase current. Figs. 11 to 18 are diagrams showing schematic diagrams of the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator.

[0022] FIG. 19 is a diagram showing an example of the waveform of the voltage generated in the stator coil. FIG. 20 is a diagram showing an example of the waveform of the voltage component of the voltage shown in FIG. 19 , which has passed through a low-pass filter and has a frequency lower than the cutoff frequency. FIGS. 21 and 22 are diagrams showing an example of the waveform of the voltage component of the voltage generated in the stator coil, which has a frequency lower than the cutoff frequency. FIG. 21 shows the waveform of the voltage component in a state where rotor rotation is permitted, and FIG. 22 shows the waveform of the voltage component in a state where rotor rotation is restricted. FIG. 23 is a diagram showing an example of the rotor rotation angle. FIG. 23 shows the change in the rotor rotation angle with respect to pulse input. FIG. 24 is a diagram comparing the waveform of the voltage component of the voltage generated in the stator coil, which has a frequency lower than the cutoff frequency. FIG. 24 is a diagram comparing the waveform of the voltage component in a state where rotor rotation is permitted with the waveform of the voltage component in a state where rotor rotation is restricted. FIG. 25 is a diagram showing an example of a data table showing the reference waveform of the voltage component of the voltage generated in the stator coil, which has a frequency lower than the cutoff frequency. Fig. 26 is a diagram showing an example of the waveform of a voltage component at a frequency lower than the cutoff frequency in the voltage generated in the stator coil, and a reference waveform of the voltage component. Figs. 27 and 28 are flowcharts showing examples of the operation of the motor-operated valve control device. Fig. 27 shows operation example 1, and Fig. 28 shows operation examples 2 and 3. In Figs. 19 to 22, 24, and 26, the horizontal axis is time and the vertical axis is voltage. In Fig. 23, the horizontal axis is time and the vertical axis is rotation angle.

[0023] The motor-operated valve device 1 according to this embodiment is used, for example, as a flow control valve that controls the flow rate of a refrigerant, which is a fluid, in an air conditioning system.

[0024] FIG. 1 shows an example of an air conditioning system 100 mounted on a vehicle. The air conditioning system 100 has a compressor 101, a condenser 102, an electric valve device 1 (electric valve 5), and an evaporator 103, which are connected in this order via piping 105. The electric valve device 1 is an expansion valve. The air conditioning system 100 also has an air conditioning control device 110. The air conditioning control device 110 is connected to the electric valve device 1 (electric valve control device 70) so that it can communicate with them. The air conditioning control device 110 uses the electric valve device 1 to control the flow rate of refrigerant flowing through the piping 105.

[0025] As shown in FIG. 2, the motor-operated valve device 1 includes a motor-operated valve 5 and a motor-operated valve control device 70.

[0026] The motor-operated valve 5 includes a valve body 10 , a can 20 , a valve element 30 , a drive mechanism 40 , and a stator 60 .

[0027] The valve body 10 includes a main body member 11 and a connecting member 13. The main body member 11 has a cylindrical shape. The main body member 11 includes a valve chamber 14, a valve port 17, and a valve seat 18. A first conduit 15 and a second conduit 16 are joined to the main body member 11. The first conduit 15 is arranged in a direction perpendicular to the axis L (the left-right direction in FIG. 2 ) and is connected to the valve chamber 14. The second conduit 16 is arranged in the direction of the axis L (the up-down direction in FIG. 2 ) and is connected to the valve chamber 14 via a valve port 17. The valve port 17 is surrounded by a ring-shaped valve seat 18 in the valve chamber 14. The main body member 11 includes a circular fitting hole 11a. The fitting hole 11a is located on the upper end surface of the main body member 11. The inner circumferential surface of the fitting hole 11a has a flat surface 11d facing leftward in FIG. 2 . A through-hole 11b that communicates with the valve chamber 14 is provided in the bottom surface of the fitting hole 11a. The connecting member 13 has an annular plate shape. The inner peripheral edge of the connecting member 13 is joined to the upper end of the main body member 11. The main body member 11 and the connecting member 13 are made of metal such as aluminum alloy, stainless steel, or brass.

[0028] The can 20 is made of a metal such as stainless steel. The can 20 has a cylindrical shape. The lower end of the can 20 is open and the upper end is closed. The lower end of the can 20 is joined to the outer periphery of the connecting member 13.

[0029] The valve body 30 has a first shaft portion 31, a second shaft portion 32, and a valve portion 33. The first shaft portion 31 has a cylindrical shape. The second shaft portion 32 has a cylindrical shape. The diameter of the second shaft portion 32 is smaller than the diameter of the first shaft portion 31. The second shaft portion 32 is coaxially connected to the upper end of the first shaft portion 31. The valve body 30 has a step portion 34, which is an upward-facing annular flat surface. The step portion 34 is located at the connection between the first shaft portion 31 and the second shaft portion 32. The valve portion 33 has a generally conical shape whose diameter decreases from top to bottom. The valve portion 33 is coaxially connected to the lower end of the first shaft portion 31. The valve portion 33 is located in the valve port 17. A variable throttle portion is formed between the valve portion 33 and the valve port 17. The valve portion 33 faces the valve port 17 and the valve seat 18. When the valve portion 33 comes into contact with the valve seat 18, the valve port 17 closes. When the valve portion 33 moves away from the valve seat 18, the valve port 17 opens.

[0030] The drive mechanism 40 moves the valve element 30 in the vertical direction (the direction of the axis L). The movement of the valve element 30 opens and closes the valve port 17. The drive mechanism 40 has a rotor 41, a valve stem holder 42, a guide bush 43, a stopper member 44, and a fixing device 45.

[0031] The rotor 41 has a cylindrical shape. The outer diameter of the rotor 41 is slightly smaller than the inner diameter of the can 20. The rotor 41 is disposed inside the can 20. The rotor 41 is rotatable relative to the valve body 10. The rotor 41 has multiple north poles and multiple south poles. The multiple north poles and multiple south poles are disposed on the outer peripheral surface of the rotor 41. The multiple north poles and multiple south poles extend in the vertical direction. The multiple north poles and multiple south poles are disposed alternately at equal angular intervals in the circumferential direction. The rotor 41 has, for example, 12 north poles and 12 south poles. The angle between adjacent north poles and south poles is 15 degrees.

[0032] FIG. 3 shows the valve stem holder 42. The valve stem holder 42 has a cylindrical shape. The lower end of the valve stem holder 42 is open. An upper wall portion 42a is provided at the upper end of the valve stem holder 42. The upper wall portion 42a has a shaft hole 42b. The valve stem holder 42 is fitted into a fitting hole 41a of the rotor 41. The valve stem holder 42 rotates together with the rotor 41. A movable stopper 42s is arranged at the lower end of the outer circumferential surface of the valve stem holder 42. The movable stopper 42s is a protrusion that protrudes radially outward. The second shaft portion 32 of the valve body 30 is arranged in the shaft hole 42b so as to be movable in the direction of the axis L. A washer 46 is arranged on the lower surface of the upper wall portion 42a of the valve stem holder 42. A valve-closing spring 47 is arranged between the washer 46 and the step portion 34 of the valve body 30. The valve-closing spring 47 is a coil spring that presses the valve element 30 toward the valve seat 18. A female thread 42c is provided on the inner circumferential surface of the valve stem holder 42. The movable stopper 42s is fixed to the rotor 41.

[0033] FIG. 4 shows the guide bush 43. The guide bush 43 has a base portion 43a and a support portion 43b. The base portion 43a has a cylindrical shape. The outer peripheral surface of the base portion 43a has a flat surface 43d. The base portion 43a is press-fitted into the fitting hole 11a of the main body member 11, and the flat surface 43d contacts the flat surface 11d of the fitting hole 11a. This causes the central axis of the main body member 11 and the central axis of the guide bush 43 to coincide on the axis L, and the guide bush 43 is correctly positioned around the axis L relative to the main body member 11. The support portion 43b has a cylindrical shape. The outer diameter of the support portion 43b is smaller than the outer diameter of the base portion 43a. The inner diameter of the support portion 43b is the same as the inner diameter of the base portion 43a. The support portion 43b is coaxially connected to the upper end portion of the base portion 43a. A male thread 43c is provided on the outer peripheral surface of the support portion 43b. The male thread 43c is threadedly engaged with the female thread 42c of the valve stem holder 42. The first shaft portion 31 of the valve element 30 is disposed inside the guide bush 43. The guide bush 43 supports the valve element 30 so that it can move in the axial L direction.

[0034] FIG. 5 shows the stopper member 44. The stopper member 44 has a stopper body 44a. The stopper body 44a has a cylindrical shape. An internal thread 44c is provided on the inner peripheral surface of the stopper body 44a. A fixed stopper 44s is disposed on the outer peripheral surface of the stopper body 44a. The fixed stopper 44s is a protrusion that protrudes radially outward. The internal thread 44c is threadedly engaged with the external thread 43c until the stopper body 44a abuts against the base 43a of the guide bush 43. This fixes the stopper member 44 to the guide bush 43. The fixed stopper 44s is fixed to the valve body 10.

[0035] The fixing device 45 has a fixing portion 45a and a flange portion 45b. The fixing portion 45a has a stepped cylindrical shape. The second shaft portion 32 of the valve body 30 is disposed inside the fixing portion 45a. The fixing portion 45a is joined to the second shaft portion 32. The flange portion 45b is connected to the lower end of the fixing portion 45a. A return spring 48 is disposed outside the fixing device 45. The return spring 48 is a coil spring.

[0036] The motor-operated valve 5 has a drive mechanism 40 that uses the rotation of the rotor 41 without reducing the speed. Instead of the drive mechanism 40, the motor-operated valve 5 may have a drive mechanism that has a speed reduction mechanism that reduces the speed of the rotation of the rotor 41.

[0037] The stator 60 has a cylindrical shape and includes an A-phase stator 61 and a B-phase stator 62.

[0038] The A-phase stator 61 has a plurality of claw-pole-shaped pole teeth 61a, 61b on its inner circumference. The tips of the pole teeth 61a face downward, and the tips of the pole teeth 61b face upward. The pole teeth 61a and the pole teeth 61b are alternately arranged at equal angular intervals in the circumferential direction. The A-phase stator 61 has, for example, 12 pole teeth 61a and 12 pole teeth 61b. The angle between adjacent pole teeth 61a and 61b is 15 degrees. The A-phase stator 61 has an A-phase coil 61c. When the A-phase coil 61c is energized, the pole teeth 61a and the pole teeth 61b become magnetic poles of opposite polarity.

[0039] The B-phase stator 62 has a plurality of claw-pole-shaped pole teeth 62a, 62b on its inner circumference. The tips of the pole teeth 62a face downward, and the tips of the pole teeth 62b face upward. The pole teeth 62a and 62b are alternately arranged at equal angular intervals in the circumferential direction. The B-phase stator 62 has, for example, 12 pole teeth 62a and 12 pole teeth 62b. The angle between adjacent pole teeth 62a and 62b is 15 degrees. The B-phase stator 62 has a B-phase coil 62c. When the B-phase coil 62c is energized, the pole teeth 62a and 62b become magnetic poles of mutually opposite polarities.

[0040] The A-phase stator 61 and the B-phase stator 62 are arranged coaxially. The A-phase stator 61 is in contact with the B-phase stator 62. When viewed from the direction of the axis L, the angle between the pole tooth 61a of the A-phase stator 61 and the pole tooth 62a of the B-phase stator 62, which are adjacent to each other, is 7.5 degrees. In other words, the B-phase stator 62 is located at a position rotated 7.5 degrees around the axis L with respect to the A-phase stator 61 from the position where the pole tooth 61a and the pole tooth 62a are aligned in the direction of the axis L.

[0041] The can 20 is disposed inside the stator 60. The rotor 41 is disposed inside the can 20. The stator 60 and the rotor 41 form a stepping motor 66. The stepping motor 66 is connected to an electric valve control device 70.

[0042] The rotor 41 rotates when consecutively numbered pulses P (P[1] to P[8]) are input to the stepping motor 66 in a repeated sequence. Specifically, the rotor 41 rotates when a drive current corresponding to the pulses P is supplied to the stator 60 of the stepping motor 66. In this specification, "inputting the pulses P to the stepping motor 66" is synonymous with "supplying a drive current corresponding to the pulses P to the stator 60 of the stepping motor 66."

[0043] When pulses P are cyclically input to the stepping motor 66 in ascending order (in the order of pulses P[1] to P[8]), the rotor 41 rotates in a first direction (clockwise in FIG. 6). When pulses P are cyclically input to the stepping motor 66 in descending order (in the order of pulses P[8] to P[1]), the rotor 41 rotates in a second direction (counterclockwise in FIG. 6).

[0044] In the motor-operated valve 5, the central axes of the valve port 17, valve seat 18, can 20, valve body 30, rotor 41, valve stem holder 42, guide bush 43, and stator 60 (A-phase stator 61, B-phase stator 62) all coincide with the axis L.

[0045] The motor-operated valve control device 70 has a substrate 71 on which multiple electronic components (not shown) are mounted. As shown in Fig. 1, the motor-operated valve control device 70 has a non-volatile memory 75, a communication device 76, a motor driver 77, a low-pass filter 78, and a computer 80. The motor-operated valve control device 70 controls the motor-operated valve 5 based on commands from the air conditioner control device 110.

[0046] The nonvolatile memory 75 stores data that needs to be retained even when the power is turned off, and is, for example, an EEPROM or a flash memory.

[0047] The communication device 76 is communicably connected to the air conditioner control device 110 via a wired communication bus 120. The air conditioner system 100 employs a communication method such as a Local Interconnect Network (LIN) or a Controller Area Network (CAN). The communication device 76 may also be connected to the air conditioner control device 110 so as to be able to communicate wirelessly.

[0048] The motor driver 77 is controlled by the computer 80. The motor driver 77 is connected to the stator 60 of the stepping motor 66. Specifically, as shown in FIG. 7, the motor driver 77 is connected to the A-phase coil 61c of the A-phase stator 61 and the B-phase coil 62c of the B-phase stator 62. The motor driver 77 supplies a drive current corresponding to the pulse P to the stator 60. The motor driver 77 supplies an A-phase current Ia to the A-phase coil 61c and a B-phase current Ib to the B-phase coil 62c.

[0049] The motor driver 77 receives a step signal (STEP) and a direction signal (DIR) from the computer 80 as signals corresponding to the pulses P. The step signal is a pulse signal. When a direction signal (e.g., an H-level signal) corresponding to a first direction is input to the motor driver 77, the step signal is input, which corresponds to the pulses P being input to the stepping motor 66 in ascending order. When a direction signal (e.g., an L-level signal) corresponding to a second direction is input to the motor driver 77, the step signal is input, which corresponds to the pulses P being input to the stepping motor 66 in descending order. Figure 8 shows the relationship between the step signal, direction signal, and pulses P input to the stepping motor 66.

[0050] Pulses P[1] to P[8] are input in sequence to stepping motor 66. In response to the input of pulses P, an A-phase current Ia is supplied to A-phase coil 61c, and in response to the input of pulses P, a B-phase current Ib is supplied to B-phase coil 62c. The A-phase current Ia and the B-phase current Ib are drive currents for rotating rotor 41.

[0051] Further, a current control signal (CONTROL) is input to the motor driver 77 from the computer 80. The current control signal is a signal for setting, in the motor driver 77, an A-phase current target value Ita and a B-phase current target value Itb, which are target values ​​for the A-phase current Ia and the B-phase current Ib.

[0052] An A-phase current target value Ita is set for each of the pulses P[1] to P[8]. A B-phase current target value Itb is set for each of the pulses P[1] to P[8]. Figure 9 shows an example of the correspondence between the pulse P and the A-phase current target value Ita and the B-phase current target value Itb.

[0053] For pulse P[1], "+I2" is set as the A-phase current target value Ita, and "0" is set as the B-phase current target value Itb. For pulse P[2], "+I1" is set as the A-phase current target value Ita, and "+I1" is set as the B-phase current target value Itb. For pulse P[3], "0" is set as the A-phase current target value Ita, and "+I2" is set as the B-phase current target value Itb. For pulse P[4], "-I1" is set as the A-phase current target value Ita, and "+I1" is set as the B-phase current target value Itb. For pulse P[5], "-I2" is set as the A-phase current target value Ita, and "0" is set as the B-phase current target value Itb. For pulse P[6], "-I1" is set as the A-phase current target value Ita, and "-I1" is set as the B-phase current target value Itb. For pulse P[7], "0" is set as the A-phase current target value Ita, and "-I2" is set as the B-phase current target value Itb. For pulse P[8], "+I1" is set as the A-phase current target value Ita, and "-I1" is set as the B-phase current target value Itb. "+I2" and "-I2" have the same current magnitude but different current directions. "+I1" and "-I1" have the same current magnitude but different current directions. "+I2" and "+I1" have different current magnitudes but the same direction.

[0054] FIG. 10 shows the waveforms of the A-phase current Ia and the B-phase current Ib when pulses P are input to the stepping motor 66 in ascending order. In FIG. 10, the A-phase current Ia has the same magnitude and direction as the A-phase current target value Ita, and the B-phase current Ib has the same magnitude and direction as the B-phase current target value Itb. In FIGS. 9 and 10, the signs (+ / -) indicate the direction of current flow. "+" indicates the direction from terminal A1 to terminal A2, or from terminal B1 to terminal B2. "-" indicates the direction from terminal A2 to terminal A1, or from terminal B2 to terminal B1. "0" indicates that no current flows.

[0055] The A-phase current Ia and the B-phase current Ib are currents controlled by pulse width modulation (PWM). The A-phase current Ia and the B-phase current Ib have waveforms that repeatedly turn on and off at regular time intervals that are shorter than the period of the pulse P. The reciprocal of this time interval is the pulse width modulation frequency (PWM frequency). The A-phase current target value Ita and the B-phase current target value Itb are average values ​​of the currents supplied to the A-phase coil 61c and the B-phase coil 62c during the period of the pulse P.

[0056] The combination of the A-phase current Ia and the B-phase current Ib varies for each pulse P. There are eight possible combinations, which are referred to as the number of pulse P patterns. A "pattern" is also called a "switching mode." The numbers (1 to 8) in pulses P[1] to P[8] are pattern numbers that identify pulses P[1] to P[8]. For example, the period of pulse P is 8 ms, and one period T including pulses P[1] to P[8] is 64 ms. The excitation mode of the stepping motor 66 is 1-2 phase excitation. The stepping motor 66 is controlled using the half-step method. The step angle of the stepping motor 66 is 3.75 degrees.

[0057] 11 to 18 are schematic diagrams showing the positional relationship between the rotor's magnetic poles and the stator's pole teeth when pulses P[1] to P[8] are input to the stepping motor. The rotor's magnetic poles and stator are shown in schematic diagrams. In FIGS. 11 to 18, to make it easier to understand the positional relationship between the rotor 41 and the stator 60 (A-phase stator 61, B-phase stator 62), the reference pole tooth 61a and the reference magnetic pole (S pole) of the rotor 41 are indicated by black circles.

[0058] When pulses P are cyclically input to the stepping motor 66 in ascending order and the rotor 41 rotates in the first direction, the rotor 41 and the stem holder 42 move downward due to the feed screw action between the female thread 42c of the stem holder 42 and the male thread 43c of the guide bush 43. The stem holder 42 presses the valve disc 30 downward via the valve-closing spring 47. The valve disc 30 moves downward, and the valve portion 33 contacts the valve seat 18. At this time, the rotor 41 is in the valve-closed position Rc. When the rotor 41 is further rotated in the first direction from this state, the valve-closing spring 47 is compressed, and the rotor 41 and the stem holder 42 move further downward. The valve disc 30 does not move downward. When the movable stopper 42s of the stem holder 42 contacts the fixed stopper 44s of the stopper member 44, rotation of the rotor 41 in the first direction is restricted. At this time, the rotor 41 is in the reference position Rx. The movable stopper 42s and the fixed stopper 44s constitute a stopper mechanism 49 that restricts the rotation of the rotor 41 in the first direction when the rotor 41 is in the reference position Rx.

[0059] When pulses P are cyclically input to the stepping motor 66 in descending order and the rotor 41 rotates in the second direction, the rotor 41 and the valve stem holder 42 move upward due to the feed screw action between the female thread 42c of the valve stem holder 42 and the male thread 43c of the guide bush 43. The valve stem holder 42 pushes the fixture 45 upward. The valve disc 30 moves upward together with the fixture 45, and the valve disc 30 moves away from the valve seat 18. The position of the rotor 41 when the flow rate of the fluid at the valve port 17 (opening of the valve port 17) is a predetermined set value in a predetermined flow measurement environment is defined as the open position Ro. The set value is set appropriately depending on the configuration and application of the motor-operated valve device 1. When the rotor 41 rotates in the second direction and reaches the fully open position Rz, the valve disc 30 is farthest from the valve port 17, and the valve port 17 is at its maximum opening.

[0060] The number of pulses P required to rotate the rotor 41 from the fully open position Rz to the reference position Rx is called the stroke number Ns. In other words, when pulses P with the stroke number Ns are input to the stepping motor 66 of the motor-operated valve 5 with the rotor 41 at the fully open position Rz, the rotor 41 is positioned at the reference position Rx. For example, the stroke number Ns is 500. The number of pulses P required to rotate the rotor 41 from the reference position Rx to the fully open position Rz is also the stroke number Ns.

[0061] An initialization number Ni is set based on the stroke number Ns. The initialization number Ni is the number of pulses P sufficient to rotate the rotor 41 from the fully open position Rz to the reference position Rx. In other words, regardless of the position of the rotor 41, inputting pulses P equal to the initialization number Ni to the stepping motor 66 positions the rotor 41 at the reference position Rx. The initialization number Ni is, for example, 1.05 to 1.3 times the stroke number Ns. The initialization number Ni is used in the initialization operation to position the rotor 41 at the reference position Rx.

[0062] 7, the motor driver 77 includes H-bridge circuits 77A and 77B and a current control unit 77C. The H-bridge circuits 77A and 77B are current circuits. The motor driver 77 drives the stepping motor 66 in a bipolar manner.

[0063] The H-bridge circuit 77A is connected to the A-phase coil 61c. The H-bridge circuit 77A has switches SW11, SW12, SW13, and SW14, which are switching elements. The H-bridge circuit 77B is connected to the B-phase coil 62c. The H-bridge circuit 77B has switches SW21, SW22, SW23, and SW24, which are switching elements. The switches SW11, SW12, SW13, and SW14 and the switches SW21, SW22, SW23, and SW24 are, for example, N-channel MOSFETs or P-channel MOSFETs, or a mixture of both.

[0064] The switches SW11, SW12, SW13, and SW14 and the switches SW21, SW22, SW23, and SW24 are controlled to be on (conductive state) or off (non-conductive state).

[0065] The current control section 77C controls the H-bridge circuits 77A and 77B in accordance with a step signal and a direction signal from the computer 80 using pulse width modulation.

[0066] When A-phase current Ia flowing from terminal A1 to terminal A2 is supplied to A-phase coil 61c: (1) The current control unit 77C turns off the switches SW12 and SW13. (2) The current control unit 77C controls the on-time (ie, duty cycle) of the switches SW11 and SW14 so that the magnitude of the A-phase current Ia is the same as the magnitude of the A-phase current target value Ita.

[0067] When A-phase current Ia flowing from terminal A2 to terminal A1 is supplied to A-phase coil 61c: (1) The current control unit 77C turns off the switches SW11 and SW14. (2) The current control unit 77C controls the ON time of the switches SW12 and SW13 so that the magnitude of the A-phase current Ia is equal to the magnitude of the A-phase current target value Ita.

[0068] When a B-phase current Ib flowing from terminal B1 to terminal B2 is supplied to the B-phase coil 62c: (1) The current control unit 77C turns off the switches SW22 and SW23. (2) The current control unit 77C controls the ON time of the switches SW21 and SW24 so that the magnitude of the B-phase current Ib is equal to the magnitude of the B-phase current target value Itb.

[0069] When a B-phase current Ib flowing from terminal B2 to terminal B1 is supplied to the B-phase coil 62c: (1) The current control unit 77C turns off the switches SW21 and SW24. (2) The current control unit 77C controls the ON time of the switches SW22 and SW23 so that the magnitude of the B-phase current Ib is the same as the magnitude of the B-phase current target value Itb.

[0070] The low-pass filter 78 is an electric circuit including a resistor and a capacitor, and includes an A-phase low-pass filter 78A and a B-phase low-pass filter 78B.

[0071] An input terminal of A-phase low-pass filter 78A is connected to terminals A1 and A2 of A-phase coil 61c, and an output terminal is connected to computer 80. A-phase low-pass filter 78A blocks (or substantially blocks) voltage components of voltage VA generated between terminals A1 and A2 of A-phase coil 61c that have frequencies equal to or higher than cutoff frequency Fc, and passes voltage component Vac that has a frequency lower than cutoff frequency Fc. Voltage component Vac is input to computer 80.

[0072] An input terminal of B-phase low-pass filter 78B is connected to terminals B1 and B2 of B-phase coil 62c, and an output terminal is connected to computer 80. B-phase low-pass filter 78B blocks (including substantially blocks) voltage components of frequencies equal to or higher than cutoff frequency Fc in voltage VB generated between terminals B1 and B2 of B-phase coil 62c, and passes voltage component Vbc of frequencies lower than cutoff frequency Fc. Voltage component Vbc is input to computer 80.

[0073] The cutoff frequency Fc is set in the low-pass filter 78 so as to effectively block (attenuate) the voltage component of the voltage VA caused by the A-phase current Ia and the voltage component of the voltage VB caused by the B-phase current Ib. The lower the cutoff frequency Fc, the more effectively these voltage components can be blocked; however, the larger the time constant of the low-pass filter 78, the greater the delay in the waveforms of the voltage components Vac and Vbc. The allowable delay time Td is the time allowed for the waveform delay caused by the low-pass filter 78. The voltage component Vac mainly includes a voltage component generated by the rotation of the rotor 41 (a voltage electromagnetically induced in the A-phase coil 61c). The voltage component Vbc mainly includes a voltage component generated by the rotation of the rotor 41 (a voltage electromagnetically induced in the B-phase coil 62c).

[0074] In this embodiment, the PWM frequency is 20 kHz, and the cutoff frequency Fc is 1000 Hz. The cutoff frequency Fc of the low-pass filter 78 is determined using, for example, the following equations (a) to (c). Vout = Vin / (sRC+1) (a) Fc=1 / (2πCR) (b) Td ≥ RC (c) where Vin is the input voltage, Vout is the output voltage, R is the resistance of the resistor, C is the capacitance of the capacitor, and Td is the allowable delay time. Equation (a) is the transfer function of the low-pass filter 78, and where ω is the angular velocity, s = jω and ω = 2πf. The output voltage Vout (voltage components Vac, Vbc) is observed while changing the cutoff frequency Fc (i.e., the resistance R and capacitance C) within a range that satisfies equations (a) to (c), and a cutoff frequency Fc that can effectively cut off the voltage component in voltage VA caused by the A-phase current Ia and the voltage component in voltage VB caused by the B-phase current Ib is selected. The cutoff frequency Fc is sufficiently lower than the PWM frequency. The cutoff frequency Fc is preferably equal to or less than one-tenth of the PWM frequency, and more preferably equal to or less than one-twentieth of the PWM frequency.

[0075] The low-pass filter 78 may be configured with an operational amplifier or a digital signal processor.

[0076] FIG. 19 shows an example of the waveform of the voltage VA generated in the A-phase coil 61c and the waveform of the voltage VB generated in the B-phase coil 62c when pulses P are input to the stepping motor 66 in ascending order. In FIG. 19, because the A-phase current Ia and the B-phase current Ib are controlled using pulse-width modulation, the voltage VA oscillates greatly at short intervals during periods corresponding to pulses P[1], P[2], P[4], P[5], P[6], and P[8], and the voltage VB oscillates greatly at short intervals during periods corresponding to pulses P[2], P[3], P[4], P[6], P[7], and P[8]. FIG. 20 shows an example of the waveform of the voltage component Vac of the voltage VA and the voltage component Vbc of the voltage VB. The voltage components Vac and Vbc are voltage components with frequencies lower than the cutoff frequency Fc that have passed through the low-pass filter 78. As shown in FIG. 20, by inputting voltage VA and voltage VB to low-pass filter 78, the voltage component generated by A-phase current Ia and the voltage component generated by B-phase current Ib can be removed.

[0077] The computer 80 is a microcomputer for embedded devices in which a CPU, ROM, RAM, input / output interface, A / D converter, etc. are incorporated into a single package. The computer 80 may also include a non-volatile memory 75, a communication device 76, and a motor driver 77. The computer 80 functions as a rotation control unit 81, an acquisition unit 82, and a determination unit 83 by the CPU executing a program stored in the ROM. The computer 80 is a processing device.

[0078] The rotation control unit 81 inputs pulses P to the stepping motor 66 to rotate the rotor 41 in a first direction or a second direction. Specifically, the rotation control unit 81 controls the motor driver 77 based on a command from the air conditioner control device 110 to supply an A-phase current Ia to the A-phase coil 61c and a B-phase current Ib to the B-phase coil 62c. The rotation control unit 81 inputs a step signal, a direction signal, and a current control signal to the motor driver 77.

[0079] The acquisition unit 82 acquires a voltage component Vac of the voltage VA generated in the A-phase coil 61c and a voltage component Vbc of the voltage VB generated in the B-phase coil 62c. In the following description, the "voltage components Vac and Vbc" will be simply referred to as the "voltage component V."

[0080] Specifically, the acquisition unit 82 acquires the voltage component V in a time series manner when the rotation control unit 81 supplies an A-phase current Ia to the A-phase coil 61c and a B-phase current Ib to the B-phase coil 62c in accordance with the pulse P[k] (k=1 to 8).

[0081] The acquiring unit 82 acquires the voltage component V in time series at a predetermined sampling period during the period from the start to the end of the pulse P. For example, the period from the start to the end of the pulse P is 8 ms, and the sampling period is 200 μs. For example, the acquiring unit 82 acquires the voltage component V 40 times in response to the input of one pulse P[k].

[0082] The voltage component V acquired over time is the waveform of the voltage component V. In this specification, a "waveform" refers to a change over time in a physical quantity (voltage) at a fixed point. When a "waveform" is visualized, it is expressed on a coordinate plane with the physical quantity on the vertical axis and time on the horizontal axis. In addition, invisible things such as a data table in which physical quantity data and time data are associated and stored in the RAM of the computer 80 or the non-volatile memory 75 are also included in the "waveform."

[0083] During the initialization operation, the determination unit 83 determines the state of the motor-operated valve 5 based on the voltage component V acquired by the acquisition unit 82. The motor-operated valve 5 has a rotation permitted state Sp and a rotation restricted state Sr. The rotation permitted state Sp is a state in which the rotor 41 has not reached the reference position Rx and rotation of the rotor 41 in the first direction is permitted. The rotation restricted state Sr is a state in which the rotor 41 has reached the reference position Rx and the movable stopper 42s abuts against the fixed stopper 44s, restricting rotation of the rotor 41 in the first direction.

[0084] 21 and 22 show examples of the waveform of the voltage component V when pulses P are input to the stepping motor 66 in ascending order. Fig. 21 shows the waveform when the motor-operated valve 5 is in the rotation-permitted state Sp. Fig. 22 shows the waveform when the motor-operated valve 5 is in the rotation-restricted state Sr.

[0085] FIG. 23 shows the rotation angle of the rotor 41 when pulses P are input to the stepping motor 66 in ascending order. In FIG. 23, the rotation angle when the motor-operated valve 5 is in the rotation-permitted state Sp is indicated by a dark line (Sp), and the rotation angle when the motor-operated valve 5 is in the rotation-restricted state Sr is indicated by a light line (Sr). When the motor-operated valve 5 is in the rotation-permitted state Sp, the rotation angle gradually increases in response to the input of pulses P[1] to P[8]. When the motor-operated valve 5 is in the rotation-restricted state Sr, the rotation angle does not change in response to the input of pulses P[1], P[2], P[7], and P[8], but decreases significantly in response to the input of pulse P[3], and gradually increases in response to the input of pulses P[4], P[5], and P[6].

[0086] FIG. 24 shows an example of the waveform of the voltage component V when pulses P are input to the stepping motor 66 in ascending order. In FIG. 24, the voltage component V when the motor-operated valve 5 is in the rotation-permitted state Sp is indicated by a thick line (Sp), and the voltage component V when the motor-operated valve 5 is in the rotation-restricted state Sr is indicated by a thin line (Sr). As shown in FIG. 24, the waveform of the voltage component V when the motor-operated valve 5 is in the rotation-permitted state Sp differs from the waveform of the voltage component V when the motor-operated valve 5 is in the rotation-restricted state Sr. Specifically, the waveforms corresponding to pulses P[1] to P[4], P[7], and P[8] differ, while the waveforms corresponding to pulses P[5] and P[6] are roughly the same. Therefore, by setting the waveform of the voltage component V when the motor-operated valve 5 is in the rotation-permitted state Sp as the reference waveform of the voltage component V and comparing the reference waveform of the voltage component V with the waveform of the voltage component V acquired by the acquisition unit 82, it is possible to determine whether the motor-operated valve 5 is in the rotation-permitted state Sp or the rotation-restricted state Sr. The waveform of the voltage component V when the motor-operated valve 5 is in the rotation restricted state Sr may be set as the reference waveform of the voltage component V.

[0087] The determination unit 83 compares the waveform of the voltage component V acquired by the acquisition unit 82 with a reference waveform of the voltage component V to determine the state of the motor-operated valve 5.

[0088] The reference waveforms of the voltage component Vac are set one by one for the pulses P[1] to P[8]. The reference waveforms of the voltage component Vac are set based on the waveforms of the voltage component Vac obtained when a drive current is supplied to the stator 60 in response to the input of the pulses P[1] to P[8] in ascending order in the motor-operated valve 5 in the rotation-permitted state Sp.

[0089] The reference waveform of the voltage component Vbc is set for each of the pulses P[1] to P[8]. The reference waveform of the voltage component Vbc is set based on the waveform of the voltage component Vbc obtained when a drive current is supplied to the stator 60 in response to the input of the pulses P[1] to P[8] in ascending order in the motor-operated valve 5 in the rotation permitted state Sp.

[0090] The reference waveform of the voltage component V is stored in the nonvolatile memory 75 as a data table.

[0091] Reference waveform tables Ca[1] to Ca[8] are stored in nonvolatile memory 75. Reference waveform tables Ca[1] to Ca[8] are reference waveforms of voltage components Vac set for pulses P[1] to P[8].

[0092] Reference waveform tables Cb[1] to Cb[8] are stored in the nonvolatile memory 75. The reference waveform tables Cb[1] to Cb[8] are reference waveforms of the voltage component Vbc set for the pulses P[1] to P[8].

[0093] FIG. 25 shows an example of the reference waveform table Ca[1]. In the data table, times t at predetermined intervals from the start of the pulse P (time 0) are associated with the reference voltage rv at that time t. The interval between the times t is the same as the sampling period (200 μs) of the acquisition unit 82. One data table has 40 pairs of time t and reference voltage rv. In FIG. 25, the unit of time t is μs. The unit of the reference voltage rv is mv. The unit of the time t and the unit of the reference voltage rv may be unique units, for example, units corresponding to the sampling period and resolution of the A / D converter of the motor-operated valve control device 70.

[0094] The determination unit 83 calculates a difference index value, which is a value indicating the degree of difference between the waveform of the voltage component V acquired by the acquisition unit 82 and the reference waveform of the voltage component V. The larger the difference index value, the greater the degree of difference between the waveform of the voltage component V and the reference waveform of the voltage component V.

[0095] The determination unit 83 calculates a dissimilarity index value sva[k] using the voltage component Vac acquired in response to the input of the pulse P[k] and the reference waveform table Ca[k].

[0096] When the acquisition unit 82 acquires a voltage component Vac at acquisition time tv in response to the input of the pulse P[k], the determination unit 83 reads out the reference voltage rv associated with the time t corresponding to the acquisition time tv from the reference waveform table Ca[k] corresponding to the pulse P[k]. The determination unit 83 calculates a value (difference value dv) obtained by subtracting the reference voltage rv from the voltage component Vac acquired by the acquisition unit 82. The determination unit 83 calculates a value (intermediate value dv2) obtained by squaring the difference value dv. The determination unit 83 calculates a dissimilarity index value sva[k] by adding together the multiple intermediate values ​​dv2 calculated in response to the input of the pulse P[k].

[0097] The determination unit 83 calculates the dissimilarity index value sva[k] using the voltage component Vac acquired by the acquisition unit 82 during a portion of the period from the start to the end of the pulse P[k]. Specifically, when a first period p1 is defined as the period from the start of the pulse P[k] to time t1 and a second period p2 is defined as the period from time t1 to time t2, the determination unit 83 calculates the dissimilarity index value sva[k] using the voltage component Vac during the second period p2. The determination unit 83 does not use the voltage component Vac during the first period p1 when calculating the dissimilarity index value sva[k]. Time t1 is a time after the start of the pulse P[k]. Time t2 is a time after time t1 and before the end of the pulse P[k]. Time t2 may be the end of the pulse P[k].

[0098] Immediately after the start of pulse P[k], the drive current is in a transient state, and voltages VA and VB are not stable. Therefore, the determination unit 83 can determine the state of the motor-operated valve 5 with higher accuracy by calculating the dissimilarity index value sva[k] using the voltage component Vac acquired by the acquisition unit 82 after a certain amount of time has passed since the start of pulse P[k] and voltages VA and VB have stabilized.

[0099] 26 shows an example of the waveform of the voltage component Vac acquired in response to the input of the pulse P[k] and the reference waveform of the voltage component Vac. In FIG. 26, the waveform of the voltage component Vac is shown by a solid line (acquired waveform), and the reference waveform of the voltage component Vac is shown by a dashed line. In FIG. 26, the length of the vertical line connecting the waveform of the voltage component Vac and the reference waveform of the voltage component Vac during the second period p2 corresponds to the difference value dv used to calculate the dissimilarity index value sva[k].

[0100] The length of the first period p1 is 5 to 50% of the period from the start to the end of the pulse P[k], and preferably 20 to 30%. The length of the second period p2 is 50 to 95% of the period from the start to the end of the pulse P[k], and preferably 70 to 80%. The determination unit 83 may calculate the dissimilarity index value sva[k] using the voltage component Vac acquired by the acquisition unit 82 during the period from the start to the end of the pulse P[k] (the entire period). In this configuration, the start of the pulse P[k] is time t1, and the end of the pulse P[k] is time t2.

[0101] When the voltage component Vac acquired at the acquisition time tv between time t1 and time t2 is v[tv], and the reference voltage rv associated with the time t corresponding to the acquisition time tv in the reference waveform data table is rv[tv], the dissimilarity index value sva is expressed by the following equation (1).

[0102]

number

[0103] The difference index value sva is not limited to one calculated using the above formula (1). The difference index value sva may relate to, for example, the transition of the magnitude of the voltage component Vac at the acquisition time tv. Specifically, the motor-operated valve control device 70 calculates a difference value dv between the voltage component Vac at the acquisition time tv corresponding to time t and a reference voltage rv associated with time t. The difference value dv is calculated as an absolute value. The motor-operated valve control device 70 determines the number of difference values ​​dv calculated for the voltage component Vac acquired during the second period p2 that are equal to or greater than a predetermined difference judgment value as the difference index value. Such a difference index value also appropriately reflects the degree of difference in the waveform shapes.

[0104] Similar to the dissimilarity index value sva[k], the determination unit 83 calculates the dissimilarity index value svb[k] using the voltage component Vbc acquired in response to the input of the pulse P[k] and the reference waveform table Cb[k]. In the following description, the "dissimilarity index value sva and the dissimilarity index value svb" will be simply referred to as the "dissimilarity index value sv."

[0105] The determination unit 83 determines the state of the motor-operated valve 5 based on the difference index value sv[k]. Specifically, the determination unit 83 compares the difference index value sv[k] with a predetermined difference determination value H. Based on the comparison result between the difference index value sv[k] and the difference determination value H, the determination unit 83 determines whether the motor-operated valve 5 is in the rotation permitted state Sp or the rotation restricted state Sr. Note that the motor-operated valve control device 70 may have difference determination values ​​H[1] to H[8] corresponding to the difference index values ​​sv[1] to sv[8]. The difference determination values ​​H[1] to H[8] may be the same value or may be different values.

[0106] Next, an example of the initialization operation of the motor-operated valve control device 70 (operation example 1) will be described with reference to FIG.

[0107] When the motor-operated valve control device 70 (computer 80) receives an initialization command from the air conditioner control device 110 (S110), it starts inputting pulses P[1] to P[8] in ascending order to the stepping motor 66 (S120). This starts the initialization operation, and a drive current corresponding to the pulses P[1] to P[8] is supplied to the stator 60, causing the rotor 41 to rotate in the first direction.

[0108] When the rotor 41 is rotating in the first direction, the motor-operated valve control device 70 acquires, in time series, a voltage component Vac of the voltage VA generated in the A-phase coil 61c and a voltage component Vbc of the voltage VB generated in the B-phase coil 62c (S130). That is, the motor-operated valve control device 70 acquires the waveform of the voltage component Vac and the waveform of the voltage component Vbc. The motor-operated valve control device 70 acquires the voltage component Vac and the voltage component Vbc when a drive current is supplied to the stator 60 in response to input of a pulse P[k] (k=1 to 8).

[0109] The motor-operated valve control device 70 calculates a dissimilarity index value sv (S140). Specifically, the motor-operated valve control device 70 calculates a dissimilarity index value sva[k] using the reference waveform table Ca[k] in response to the input of the pulse P[k]. The motor-operated valve control device 70 calculates a dissimilarity index value svb[k] using the reference waveform table Cb[k] in response to the input of the pulse P[k].

[0110] The motor-operated valve control device 70 determines the state of the motor-operated valve 5 based on the difference index value sv[k] by the end of the pulse P[k] (S150). In other words, the motor-operated valve control device 70 determines the state of the motor-operated valve 5 based on the difference index value sv[k] before the next pulse P[j] (j=k+1 when k=1 to 7, j=1 when k=8) after the pulse P[k] is input. The pulse P[k] is the pulse to be determined. Specifically, the motor-operated valve control device 70 compares the difference index value sva[k] with the difference judgment value H, and compares the difference index value svb[k] with the difference judgment value H. When the difference index value sva[k] is equal to or greater than the difference judgment value H and the difference index value svb[k] is equal to or greater than the difference judgment value H, the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation restricted state Sr. The motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation permitted state Sp when the difference index value sva[k] is smaller than the difference determination value H, or when the difference index value svb[k] is smaller than the difference determination value H. Note that the motor-operated valve control device 70 may determine the state of the motor-operated valve 5 using only one of the difference index value sva[k] and the difference index value svb[k].

[0111] When the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation restricted state Sr (Y in S160), it stops inputting pulses P to the stepping motor 66 and notifies the air conditioner control device 110 that the initialization operation has been completed (successful) (S170).

[0112] When the motor-operated valve 5 is in the rotation-permitted state Sp (N in S160) and the number of pulses P input to the stepping motor 66 exceeds the initialization number Ni (Y in S180), the motor-operated valve control device 70 stops inputting pulses P to the stepping motor 66 and notifies the air conditioner control device 110 of the completion (failure) of the initialization operation (S190).

[0113] When the number of pulses P input to the stepping motor 66 is equal to or less than the initialization number Ni (N in S190), the motor-operated valve control device 70 executes steps S130 to S180 again.

[0114] If the initialization operation is successful, the rotor 41 is positioned at the reference position Rx.

[0115] In the above-described operation example 1, the motor-operated valve control device 70 calculates the difference index value sv[k] in response to the input of the pulse P[k], and determines the state of the motor-operated valve 5 before the input of the pulse P[j] following the pulse P[k]. The motor-operated valve control device 70 calculates the difference index value sv[k] using the voltage component V acquired during a second period p2 (times t1 to t2), which is part of the period from the start to the end of the pulse P[k].

[0116] For example, if time t2 is near the end of pulse P[k], the motor-operated valve control device 70 may calculate the difference index value sv[k] during the input period of pulse P[j] following pulse P[k]. In this configuration, the motor-operated valve control device 70 determines whether or not the motor-operated valve 5 is in the rotation restricted state Sr using the difference index value sv[k] during the input period of pulse P[j] following pulse P[k]. Operation examples 2 and 3 in this configuration will be described with reference to FIG.

[0117] In Operation Examples 2 and 3, when the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation restricted state Sr, it positions the rotor 41 at a position where the motor-operated valve 5 is in the rotation restricted state Sr (S165). In Operation Examples 2 and 3, the steps other than step S165 are the same as those in Operation Example 1. Step S165 in Operation Examples 2 and 3 will be described.

[0118] In the second operational example, when the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation-restricted state Sr based on the difference index value sv[k] during the input period of the pulse P[j] following the pulse P[k] (Y in S160), it inputs one pulse P[k] following the pulse P[j] (S165). For example, when the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation-restricted state Sr based on the difference index value sv[7] during the input period of the pulse P[8], it inputs one pulse P[7] following the pulse P[8]. This positions the rotor 41 at a position corresponding to the pulse P[k] at which the motor-operated valve 5 changes from the rotation-permitted state Sp to the rotation-restricted state Sr. The motor-operated valve control device 70 then stops inputting pulses P to the stepping motor 66 and notifies the air conditioner control device 110 of the completion (success) of the initialization operation (S170).

[0119] In Operation Example 3, when the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation-restricted state Sr based on the difference index value sv[k] during the input period of the pulse P[j] following the pulse P[k] (Y in S160), it inputs pulses P in ascending order following pulse P[j] until it inputs pulse P[k] (S165). For example, when the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation-restricted state Sr based on the difference index value sv[7] during the input period of pulse P[8], it inputs pulses P[1] to P[7] following pulse P[8]. This positions the rotor 41 at a position corresponding to pulse P[k], at which the motor-operated valve 5 changes from the rotation-permitted state Sp to the rotation-restricted state Sr. The motor-operated valve control device 70 then stops inputting pulses P to the stepping motor 66 and notifies the air conditioner control device 110 of the completion (success) of the initialization operation (S170).

[0120] As described above, the motor-operated valve device 1 includes the motor-operated valve 5 and the motor-operated valve control device 70. The motor-operated valve 5 includes the valve body 10 having the valve port 17, the stepping motor 66 having the rotor 41 and the stator 60, and the valve element 30 that moves relative to the valve port 17 when the rotor 41 rotates. The motor-operated valve control device 70 includes a low-pass filter 78 and a computer 80. The A-phase current Ia and the B-phase current Ib, which are controlled by pulse-width modulation and are used to rotate the rotor 41, are supplied to the A-phase coil 61c and the B-phase coil 62c of the stator 60. The low-pass filter 78 has a cutoff frequency Fc lower than the PWM frequency used in pulse-width modulation, and passes a voltage component Vac of the voltage VA generated across the A-phase coil 61c that has a frequency lower than the cutoff frequency Fc and a voltage component Vbc of the voltage VB generated across the B-phase coil 62c that has a frequency lower than the cutoff frequency Fc. The computer 80 uses the voltage components Vac and Vbc that have passed through the low-pass filter 78 to determine whether the motor-operated valve 5 is in the rotation restricted state Sr in which the rotation of the rotor 41 is restricted.

[0121] This configuration allows the relatively high-frequency voltage component generated by the A-phase current Ia to be removed from the voltage VA across the A-phase coil 61c, thereby preventing the voltage component generated by the A-phase current Ia from being obscured by the voltage component generated by the rotation of the rotor 41. The relatively high-frequency voltage component generated by the B-phase current Ib to be removed from the voltage VB across the B-phase coil 62c, thereby preventing the voltage component generated by the B-phase current Ib from being obscured by the voltage component generated by the B-phase current Ib. This makes it possible to determine whether the motor-operated valve 5 is in the rotation-restricted state Sr based on the voltage VA even when the A-phase current Ia is supplied to the A-phase coil 61c. It also makes it possible to determine whether the motor-operated valve 5 is in the rotation-restricted state Sr based on the voltage VB even when the B-phase current Ib is supplied to the B-phase coil 62c. This allows for timely determination of whether the rotation of the rotor 41 of the stepping motor 66 is restricted.

[0122] Furthermore, the computer 80 of the motor-operated valve control device 70 determines whether the motor-operated valve 5 is in the rotation restricted state Sr based on the degree of difference between the waveform of the voltage component Vac and the reference waveform of the voltage component Vac, and the degree of difference between the waveform of the voltage component Vbc and the reference waveform of the voltage component Vbc. In this way, the motor-operated valve control device 70 can determine the state of the motor-operated valve 5 with higher accuracy than a configuration that determines the state of the motor-operated valve 5 based on the area of ​​the waveform or the maximum amplitude of the waveform.

[0123] A motor driver 77 is connected to the A-phase coil 61c and the B-phase coil 62c. A plurality of pulses P having consecutive numbers are input to the motor driver 77 in a sequential manner. The motor driver 77 supplies an A-phase current Ia to the A-phase coil 61c and a B-phase current Ib to the B-phase coil 62c in response to the plurality of pulses P, thereby rotating the rotor 41. A computer 80 starts inputting the plurality of pulses P to the motor driver 77. The computer 80 acquires voltage components Vac and Vbc when the A-phase current Ia and the B-phase current Ib are supplied to the B-phase coil 62c in response to the pulses P[k] input to the motor driver 77. The computer 80 uses the voltage components Vac and Vbc to determine whether the motor-operated valve 5 is in the rotation restriction state Sr. If the computer 80 determines that the motor-operated valve 5 is in the rotation restriction state Sr, it stops inputting the plurality of pulses P before inputting the pulse P[j] next to the pulse P[k]. In this way, the rotor 41 is positioned at a position corresponding to the pulse P[k] at which the motor-operated valve 5 changes from the rotation-permitted state Sp to the rotation-restricted state Sr. Therefore, the rotor 41 can be more accurately positioned at the reference position Rx.

[0124] In a configuration in which the computer 80 determines whether the motor-operated valve 5 is in the rotation-restricted state Sr using the voltage component Vac and the voltage component Vbc during the input period of the pulse P[j] following the pulse P[k], the computer 80 may operate as follows. When the computer 80 determines that the motor-operated valve 5 is in the rotation-restricted state Sr, it inputs a pulse P[k] following the pulse P[j] to the motor driver 77, and then stops inputting the multiple pulses P. Alternatively, when the computer 80 determines that the motor-operated valve 5 is in the rotation-restricted state Sr, it inputs pulses P to the motor driver 77 in ascending order following the pulse P[j] until it inputs a pulse P[k] to the motor driver 77, and then stops inputting the multiple pulses P. By doing this, even in this configuration, the rotor 41 is positioned at a position corresponding to the pulse P[k] at which the motor-operated valve 5 changes from the rotation-permitted state Sp to the rotation-restricted state Sr. Therefore, the rotor 41 can be more accurately positioned at the reference position Rx.

[0125] In the motor-operated valve device 1 described above, the motor-operated valve control device 70 drives the stepping motor 66 in a half-step mode. The motor-operated valve control device 70 may drive the stepping motor 66 in micro-step modes 1 and 2. The motor-operated valve control device 70 may drive the stepping motor 66 in a full-step mode. In the half-step mode, the magnitude of the drive current has three levels (I2, I1, 0). In the micro-step mode 1, the magnitude of the drive current has five levels. In the micro-step mode 2, the magnitude of the drive current has nine levels.

[0126] 29 and 30 show the rotation angle and voltage components V (voltage components Vac, voltage components Vbc) of the rotor 41 when the stepping motor 66 is driven by microstep method 1. FIGS. 31 and 32 show the rotation angle and voltage components V (voltage components Vac, voltage components Vbc) of the rotor 41 when the stepping motor 66 is driven by microstep method 2. In FIGS. 29 and 31, the horizontal axis represents time and the vertical axis represents the rotation angle. In FIGS. 30 and 32, the horizontal axis represents time and the vertical axis represents voltage.

[0127] 29 and 31 show the rotation angle of the rotor 41 when pulses P are input in ascending order to the stepping motor 66. In Figures 29 and 31, the rotation angle when the motor-operated valve 5 is in the rotation-permitted state Sp is shown by a dark line (Sp), and the rotation angle when the motor-operated valve 5 is in the rotation-restricted state Sr is shown by a light line (Sr).

[0128] 30 and 32 show examples of the waveform of the voltage component V when pulses P are input in ascending order to the stepping motor 66. In Figures 30 and 32, the voltage component V when the motor-operated valve 5 is in the rotation-permitted state Sp is shown by a thick line (Sp), and the voltage component V when the motor-operated valve 5 is in the rotation-restricted state Sr is shown by a thin line (Sr).

[0129] Even when the stepping motor 66 is driven by the microstep method, the same (substantially the same) operational effect can be achieved as when the stepping motor 66 is driven by the half-step method.

[0130] In this specification, terms indicating a shape, such as "cylinder" or "column," are also used to refer to members or portions of members that substantially have the shape of the term. For example, a "cylindrical member" includes both a cylindrical member and a substantially cylindrical member. In addition, in this specification, the term "same" can include both the exact same and the substantially same.

[0131] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Any modifications, additions, deletions, or design changes of components made by a person skilled in the art to the above embodiments, or any combinations of features of the embodiments, are also included within the scope of the present invention as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0132] 1...motor-operated valve device, 5...motor-operated valve, 10...valve body, 11...body member, 11a...fitting hole, 11b...through hole, 11d...flat surface, 13...connecting member, 14...valve chamber, 15...first conduit, 16...second conduit, 17...valve port, 18...valve seat, 20...can, 30...valve body, 31...first shaft portion, 32...second shaft portion, 33...valve portion, 34...step portion, 40...drive mechanism, 41...rotor, 41a...fitting hole, 42...valve stem holder 42a...upper wall portion, 42b...shaft hole, 42c...female thread, 42s...movable stopper, 43...guide bush, 43a...base portion, 43b...support portion, 43c...male thread, 43d...flat surface, 44...stopper member, 44a...stopper body, 44c...female thread, 44s...fixed stopper, 45...fixing device, 45a...fixing portion, 45b...flange portion, 46...washer, 47...valve closing spring, 48...return spring , 49...Stopper mechanism, 60...Stator, 61...A-phase stator, 61a...Pole teeth, 61b...Pole teeth, 61c...A-phase coil, 62...B-phase stator, 62a...Pole teeth, 62b...Pole teeth, 62c...B-phase coil, 66...Stepping motor, 70...Motor-operated valve control device, 71...Substrate, 75...Non-volatile memory, 76...Communication device, 77...Motor driver, 77A...H-bridge circuit, 77B...H-bridge circuit, 77C...Current control unit, 78...Low-pass filter, 78A...A-phase low-pass filter, 78B...B-phase low-pass filter, 80...Computer, 81...Rotation control unit, 82...Acquisition unit, 83...Determination unit, 100...Air conditioning system, 101...Compressor, 102...Condenser, 103...Evaporator, 105...Pipe, 110...Air conditioning control device, 120...Wired communication bus, L...Axis

Claims

1. An electric valve control device for controlling an electric valve having a valve body having a valve port, a stepping motor having a rotor and a stator, and a valve element that moves relative to the valve port when the rotor rotates, The motor-operated valve control device has a low-pass filter and a processing device, a motor driver that supplies a drive current controlled by a pulse width modulation method to rotate the rotor is connected to the coil of the stator; When a plurality of pulses having consecutive numbers are input to the motor driver in a repeated order, the motor driver supplies the driving current corresponding to the plurality of pulses to the coil to rotate the rotor, the low-pass filter has a cutoff frequency lower than a pulse width modulation frequency used in the pulse width modulation method, and passes a voltage component of a voltage generated in the coil that has a frequency lower than the cutoff frequency; The processing device commencing input of the plurality of pulses to the motor driver; a voltage component that has passed through the low-pass filter when the drive current corresponding to the pulse input to the motor driver (hereinafter referred to as the "determination target pulse") is supplied to the coil, and the voltage component is used to determine whether the motor-operated valve is in a rotation restriction state in which rotation of the rotor is restricted; When it is determined that the motor-operated valve is in the rotation restricted state, the motor-operated valve control device stops input of the plurality of pulses before inputting a pulse next to the pulse to be determined.

2. An electric valve control device for controlling an electric valve having a valve body having a valve port, a stepping motor having a rotor and a stator, and a valve body that moves relative to the valve port when the rotor rotates, The motor-operated valve control device has a low-pass filter and a processing device, a motor driver that supplies a drive current controlled by a pulse width modulation method to rotate the rotor is connected to the coil of the stator; When a plurality of pulses having consecutive numbers are input to the motor driver in a repeated order, the motor driver supplies the driving current corresponding to the plurality of pulses to the coil to rotate the rotor, the low-pass filter has a cutoff frequency lower than a pulse width modulation frequency used in the pulse width modulation method, and passes a voltage component of a voltage generated in the coil that has a frequency lower than the cutoff frequency; The processing device commencing input of the plurality of pulses to the motor driver; a voltage component that has passed through the low-pass filter when the drive current corresponding to a pulse input to the motor driver (hereinafter referred to as a "target pulse") is supplied to the coil, and the voltage component is used during an input period of a pulse following the target pulse to determine whether the motor-operated valve is in a rotation restriction state in which rotation of the rotor is restricted; When it is determined that the motor-operated valve is in the rotation restricted state, the motor-operated valve control device inputs a pulse having the same number as the pulse to be determined, following the pulse next to the pulse to be determined, to the motor driver, and stops the input of the multiple pulses.

3. An electric valve control device for controlling an electric valve having a valve body having a valve port, a stepping motor having a rotor and a stator, and a valve body that moves relative to the valve port when the rotor rotates, The motor-operated valve control device has a low-pass filter and a processing device, a motor driver that supplies a drive current controlled by a pulse width modulation method to rotate the rotor is connected to the coil of the stator; When a plurality of pulses having consecutive numbers are input to the motor driver in a repeated order, the motor driver supplies the driving current corresponding to the plurality of pulses to the coil to rotate the rotor, the low-pass filter has a cutoff frequency lower than a pulse width modulation frequency used in the pulse width modulation method, and passes a voltage component of a voltage generated in the coil that has a frequency lower than the cutoff frequency; The processing device commencing input of the plurality of pulses to the motor driver; a voltage component that has passed through the low-pass filter when the drive current corresponding to a pulse input to the motor driver (hereinafter referred to as a "target pulse") is supplied to the coil, and the voltage component is used during an input period of a pulse following the target pulse to determine whether the motor-operated valve is in a rotation restriction state in which rotation of the rotor is restricted; When it is determined that the motor-operated valve is in the rotation restricted state, the motor-operated valve control device inputs the plurality of pulses to the motor driver in sequence until a pulse having the same number as the pulse to be determined is input to the motor driver following the pulse to be determined, and then stops inputting the plurality of pulses.

4. The electric valve control device according to any one of claims 1 to 3, wherein the processing device determines whether the electric valve is in the rotation restricted state based on the degree of difference between the waveform of the voltage component and a reference waveform of the voltage component.

5. 4. The electrically operated valve control device according to claim 1, wherein the cutoff frequency is set based on the pulse width modulation frequency.

6. A motor-operated valve device comprising the motor-operated valve and the motor-operated valve control device according to any one of claims 1 to 3.

7. A method for determining the state of an electrically operated valve having a valve body having a valve port, a stepping motor having a rotor and a stator, and a valve element that moves relative to the valve port when the rotor rotates, comprising: a motor driver that supplies a drive current controlled by a pulse width modulation method to rotate the rotor is connected to the coil of the stator; When a plurality of pulses having consecutive numbers are input to the motor driver in a repeated order, the motor driver supplies the driving current corresponding to the plurality of pulses to the coil to rotate the rotor, commencing input of the plurality of pulses to the motor driver; inputting the voltage generated in the coil to a low-pass filter having a cutoff frequency lower than a pulse width modulation frequency used in the pulse width modulation method and allowing voltage components of the voltage generated in the coil having frequencies lower than the cutoff frequency to pass; a voltage component that has passed through the low-pass filter when the drive current corresponding to the pulse input to the motor driver (hereinafter referred to as the "determination target pulse") is supplied to the coil, and the voltage component is used to determine whether the motor-operated valve is in a rotation restriction state in which rotation of the rotor is restricted; When it is determined that the motor-operated valve is in the rotation restricted state, the input of the plurality of pulses is stopped before the next pulse of the pulse to be determined is input.

8. A method for determining the state of an electrically operated valve having a valve body having a valve port, a stepping motor having a rotor and a stator, and a valve element that moves relative to the valve port when the rotor rotates, comprising: a motor driver that supplies a drive current controlled by a pulse width modulation method to rotate the rotor is connected to the coil of the stator; When a plurality of pulses having consecutive numbers are input to the motor driver in a repeated order, the motor driver supplies the driving current corresponding to the plurality of pulses to the coil to rotate the rotor, commencing input of the plurality of pulses to the motor driver; inputting the voltage generated in the coil to a low-pass filter having a cutoff frequency lower than a pulse width modulation frequency used in the pulse width modulation method and allowing voltage components of the voltage generated in the coil having frequencies lower than the cutoff frequency to pass; a voltage component that has passed through the low-pass filter when the drive current corresponding to a pulse input to the motor driver (hereinafter referred to as a "target pulse") is supplied to the coil, and the voltage component is used during an input period of a pulse following the target pulse to determine whether the motor-operated valve is in a rotation restriction state in which rotation of the rotor is restricted; A method for determining the state of an electric valve, when it is determined that the electric valve is in the rotation restriction state, (i) inputting a pulse having the same number as the pulse to be determined following the pulse to be determined to the motor driver, and stopping the input of the plurality of pulses, or (ii) inputting the plurality of pulses to the motor driver in order until inputting a pulse having the same number as the pulse to be determined following the pulse to be determined to the motor driver, and stopping the input of the plurality of pulses.

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