Electric valve control device, electric valve device, and electric valve state determination method

Abstract

[Problem] To provide: an electric valve control device capable of determining whether or not the rotation of a rotor of a stepping motor is regulated even when a drive current is flowing through a coil of the stepping motor; an electric valve device; and an electric valve state determination method. [Solution] A computer 80 of an electric valve control device uses information related to a change amount of a drive current flowing through an A-phase coil 61c of a stepping motor 66 in a determination section during a change period in which the drive current changes from a first current value to a second current value to thereby determine whether or not the rotation of a rotor 41 of the stepping motor 66 is regulated.

Description

Motor-operated valve control device, motor-operated valve device, and method for determining state of motor-operated valve

[0001] The present invention relates to a motor-operated valve control device, a motor-operated valve device including the motor-operated valve control device, and a method for determining a state of a motor-operated valve.

[0002] Patent Document 1 describes an example of a conventional motor-operated valve. The motor-operated valve includes a valve main body, a valve body, a stepping motor, and a stopper mechanism. The stepping motor includes a rotor and a stator. When a drive current is supplied to coils of the stator (an A-phase coil and a B-phase coil), the rotor rotates. The valve body moves in accordance with rotation of the rotor. The stopper mechanism restricts rotation of the rotor in a first direction when the rotor is at a reference position.

[0003] The motor-operated valve is controlled by the motor-operated valve control device. In an initialization operation, the motor-operated valve control device supplies a drive current to the coils to rotate the rotor in the first direction, and positions the rotor at the reference position.

[0004] Specifically, the motor-operated valve control device acquires a voltage generated in the coils by rotation of the rotor (a voltage electromagnetically induced in the coils), and determines whether rotation of the rotor in the first direction is restricted based on the voltage. When the motor-operated valve control device determines that rotation of the rotor in the first direction is restricted, the motor-operated valve control device stops rotation of the rotor.

[0005] Japanese Patent No. 7254400

[0006] The motor-operated valve control device controls the stepping motor by a 1-2 phase excitation method. In the 1-2 phase excitation method, there are a two-phase excitation period and a one-phase excitation period. In the two-phase excitation period, a drive current is supplied to both the A-phase coil and the B-phase coil. In the one-phase excitation period, a drive current is supplied to only one of the A-phase coil and the B-phase coil.

[0007] During the two-phase excitation period, the voltage generated in the A-phase coil includes a voltage component generated by the drive current and a voltage component generated by the rotation of the rotor, and the voltage generated in the B-phase coil also includes a voltage component generated by the drive current and a voltage component generated by the rotation of the rotor. Therefore, it is difficult for the electric valve control device to acquire only the voltage generated in the coil due to the rotation of the rotor.

[0008] During the single-phase excitation period, if drive current is supplied only to the A-phase coil, the voltage generated in the B-phase coil will include only the voltage component generated by the rotor's rotation. If drive current is supplied only to the B-phase coil, the voltage generated in the A-phase coil will include only the voltage component generated by the rotor's rotation. The electric valve control device can obtain the voltage generated in the A-phase coil and the B-phase coil that is not supplied with drive current as the voltage generated by the rotor's rotation.

[0009] Therefore, the electric valve control device determines whether the rotation of the rotor in the first direction is restricted based on the voltage generated in the other coil when drive current is supplied to only one of the A-phase coil and the B-phase coil.

[0010] However, in a configuration where the electric valve control device controls the stepping motor using a two-phase excitation method, drive current is always supplied to both the A-phase coil and the B-phase coil. Therefore, the electric valve control device cannot obtain the voltage generated in the coils by the rotation of the rotor, making it difficult to determine whether or not the rotation of the rotor in the first direction is restricted.

[0011] Therefore, the present invention aims to provide an electric valve control device and an electric valve device that can determine whether or not the rotation of the rotor is restricted even when a drive current is supplied to the stator coil, as well as a method for determining the state of an electric valve.

[0012] The inventors measured the drive current flowing through the stator coil using multiple electric valves and diligently studied the measurement results. The drive current alternates between a first current value and a second current value. The period from when the drive current changes from the first current value to the second current value is defined as the change period. The inventors found a difference between the waveform of the drive current during the change period in an electric valve where the rotor rotation is restricted and the waveform of the drive current during the change period in an electric valve where the rotor rotation is not restricted, leading to the present invention.

[0013] To achieve the above objective, an electric valve control device according to one aspect of the present invention is an electric valve control device for controlling an electric valve having a valve body having a valve port, a rotor, a stator equipped with a coil to which a drive current for rotating the rotor is supplied, and a valve body that moves relative to the valve port when the rotor rotates, and is characterized by having a processing device that determines whether or not the rotation of the rotor is restricted using information relating to the amount of change of the drive current in a part of the change period from a first current value to a second current value in which the drive current flowing through the coil changes.

[0014] In the present invention, it is preferable that the start time of the partial section is the same as the start time of the change period.

[0015] In the present invention, it is preferable that the information includes the average value of the change in the drive current.

[0016] In the present invention, it is preferable that the information includes the amount of variation in the amount of change of the drive current.

[0017] In the present invention, it is preferable that the electric valve has a stopper mechanism that restricts the rotation of the rotor in a first direction when the rotor is in a reference position, and the processing device determines that the rotation of the rotor in the first direction is restricted by the stopper mechanism when the amount of variation is greater than or equal to a first determination value when the rotor is rotating in the first direction.

[0018] In the present invention, it is preferable that the processing device determines that the rotation of the rotor in the first and second directions is restricted when the amount of variation is less than or equal to a second determination value which is smaller than the first determination value.

[0019] To achieve the above objective, another embodiment of the present invention provides an electric valve device comprising the electric valve control device and the electric valve.

[0020] To achieve the above objective, another embodiment of the present invention provides a method for determining the state of an electric valve, comprising: a valve body having a valve port; a rotor; a stator equipped with a coil to which a drive current for rotating the rotor is supplied; and a valve body that moves relative to the valve port when the rotor rotates, characterized in that the method determines whether or not the rotation of the rotor is restricted using information relating to the amount of change in the drive current flowing through the coil during a partial change period from a first current value to a second current value.

[0021] According to the present invention, information relating to the amount of change in the drive current flowing through the stator coil during a portion of the change period from a first current value to a second current value is used to determine whether or not the rotation of the rotor is restricted. In this way, it is possible to determine whether or not the rotation of the rotor is restricted even when drive current is supplied to the stator coil.

[0022] This is a block diagram of an air conditioner having an electric valve device. This is a cross-sectional view of the electric valve device. This is a plan view of the valve shaft holder, stopper member, rotor, and stator of the electric valve device. This diagram schematically shows the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[1] is input). This diagram schematically shows the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[2] is input). This diagram schematically shows the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[3] is input). This diagram schematically shows the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[4] is input). This diagram schematically shows the computer, motor driver, and stepping motor of the electric valve control device of the electric valve device. This diagram shows an example of the relationship between pulses input to the stepping motor and step signals and direction signals input to the motor driver. This diagram shows an example of the correspondence between pulses and A-phase current target values ​​and B-phase current target values. This diagram schematically shows examples of A-phase current waveforms and B-phase current waveforms. This is a diagram showing an example of the waveform of the drive current flowing through the stator coil. This is a schematic diagram showing the waveform of the drive current flowing through the stator coil. This is a diagram showing an example of the waveform of the drive current (a state in which rotor rotation is permitted). This is a diagram showing another example of the waveform of the drive current (a state in which rotor rotation is restricted). This is a diagram showing an example of the relationship between the change in drive current and the state of the motor valve. This is a diagram showing another example of the relationship between the change in drive current and the state of the motor valve. This is a flowchart showing the first example of operation of the motor valve control device. This is a flowchart showing the second example of operation of the motor valve control device. This is a flowchart showing the third example of operation of the motor valve control device.

[0023] The following describes an electric valve device according to one embodiment of the present invention.

[0024] The electric valve device 1 according to this embodiment is incorporated into, for example, the refrigeration cycle system of an air conditioner and used as a flow control valve to control the flow rate of refrigerant. The electric valve device 1 includes an electric valve 5 and an electric valve control device 70. Figure 1 shows a block diagram of an air conditioner 100 having the electric valve device 1. Figure 2 shows a cross-sectional view of the electric valve device 1.

[0025] The air conditioner 100 has a compressor 101, a condenser 102, an electric valve device 1 (electric valve 5), and an evaporator 103 connected in order via piping 105. The electric valve device 1 is an expansion valve. The air conditioner 100 has an air conditioner control device 110. The air conditioner control device 110 is communicatively connected to the electric valve device 1 (electric valve control device 70). The air conditioner control device 110 controls the flow rate of refrigerant flowing through piping 105 using the electric valve device 1.

[0026] The electric valve 5 comprises a valve body 10, a can 20, a valve element 30, a drive mechanism 40, and a stator 60.

[0027] The valve body 10 comprises a main body member 11 and a connecting member 13. The main body member 11 has a cylindrical shape. The main body member 11 has a valve chamber 14 and a valve opening 17 connected to the valve chamber 14. A first conduit 15 and a second conduit 16 are joined to the main body member 11. The first conduit 15 is connected to the valve chamber 14. The second conduit 16 is connected to the valve opening 17. The main body member 11 has an annular valve seat 18 surrounding the valve opening 17 in the valve chamber 14. The main body member 11 has a circular fitting hole 11a. The fitting hole 11a is located on the upper end surface of the main body member 11. A through hole 11b leading to the valve chamber 14 is provided on the bottom surface of the fitting hole 11a. The connecting member 13 has an annular plate shape. The inner periphery 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 can 20 is open at the lower end and closed at the upper end. The lower end of the can 20 is joined to the outer edge 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 and the second shaft portion 32 have 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 stepped portion 34 which is an annular plane facing upward. The stepped portion 34 is located at the connection point between the first shaft portion 31 and the second shaft portion 32. The valve portion 33 has a conical shape in which the 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 throttling 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 opening 17 closes. When the valve portion 33 moves away from the valve seat 18, the valve opening 17 opens.

[0030] The drive mechanism 40 moves the valve body 30 in the vertical direction (axis L direction). The movement of the valve body 30 opens and closes the valve port 17. The drive mechanism 40 includes a rotor 41, a valve stem holder 42, a movable stopper 42s, a guide bush 43, a stopper member 44, a fixed stopper 44s, a retaining member 45, a washer 46, a valve closing spring 47, and a return spring 48.

[0031] Figure 3 shows a plan view of the rotor 41, valve stem holder 42, stopper member 44, and stator 60. In Figure 3, the magnetic poles of the rotor 41 and the stator 60 are schematically shown. In Figure 3, the radially outward direction of the figure shown as the stator 60 corresponds to the upper part of the stator 60, and the radially inward direction corresponds to the lower part.

[0032] 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 positioned inside the can 20. The rotor 41 is rotatable relative to the valve body 10. The rotor 41 has a plurality of north poles and a plurality of south poles. The plurality of north poles and a plurality of south poles are arranged on the outer circumferential surface of the rotor 41. The plurality of north poles and a plurality of south poles extend in the vertical direction. The plurality of north poles and a plurality of south poles are arranged alternately at equal angular intervals in the circumferential direction. For example, the rotor 41 has 12 north poles and 12 south poles. The angle between adjacent north poles and south poles is 15 degrees. The position of the rotor 41 is related to the opening degree of the valve port 17. The rotor 41 is a magnetic rotor.

[0033] The valve stem holder 42 has a cylindrical shape. The lower end of the valve stem holder 42 is open. The valve stem holder 42 has an upper wall portion 42a with a shaft hole 42b. The valve stem holder 42 is fitted into the fitting hole 41a of the rotor 41 and rotates together with the rotor 41. A movable stopper 42s is integrally provided on the outer circumferential surface of the valve stem holder 42. The second shaft portion 32 of the valve body 30 is positioned in the shaft hole 42b, and the second shaft portion 32 is movable vertically within the shaft hole 42b. A valve closing spring 47 is positioned between a washer 46 positioned on the lower surface of the upper wall portion 42a of the valve stem holder 42 and the stepped portion 34 of the valve body 30. The valve closing spring 47 is a coil spring and pushes the valve body 30 toward the valve seat 18. An internal 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.

[0034] The guide bush 43 has a base portion 43a and a support portion 43b. The base portion 43a and the support portion 43b have a cylindrical shape. The base portion 43a is press-fitted into the fitting hole 11a of the main body member 11. The support portion 43b is coaxially connected to the upper end of the base portion 43a. A male thread 43c is provided on the outer circumferential surface of the support portion 43b. The male thread 43c is screwed into the female thread 42c of the valve stem holder 42. The first shaft portion 31 of the valve body 30 is positioned inside the guide bush 43. The guide bush 43 supports the valve body 30 so that it can move in the axial direction L.

[0035] The stopper member 44 has a cylindrical shape. The stopper member 44 is fixed to the lower end of the support portion 43b of the guide bush 43. A fixed stopper 44s is integrally provided on the outer circumferential surface of the stopper member 44. The fixed stopper 44s is fixed to the valve body 10.

[0036] The retaining member 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 positioned 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 positioned outside the retaining member 45. The return spring 48 is a coil spring.

[0037] The electric valve 5 has a drive mechanism 40 that uses the rotor 41 without reducing its rotation speed. Alternatively, the electric valve 5 may have a drive mechanism that has a reduction mechanism to reduce the rotation speed of the rotor 41 instead of the drive mechanism 40.

[0038] The stator 60 has a cylindrical shape. The stator 60 has an A-phase stack 61 and a B-phase stack 62.

[0039] The A-phase stack 61 has multiple claw-pole type pole teeth 61a and 61b on its inner circumference. The tips of the pole teeth 61a point downward, and the tips of the pole teeth 61b point upward. The pole teeth 61a and 61b are arranged alternately at equal angular intervals in the circumferential direction. For example, the A-phase stack 61 has 12 pole teeth 61a and 12 pole teeth 61b. The angle between adjacent pole teeth 61a and pole teeth 61b is 15 degrees. The A-phase stack 61 has an A-phase coil 61c. When the A-phase coil 61c is energized, the pole teeth 61a and 61b become magnetic poles of opposite polarity.

[0040] The B-phase stack 62 has multiple claw-pole type pole teeth 62a and 62b on its inner circumference. The tips of the pole teeth 62a point downward, and the tips of the pole teeth 62b point upward. The pole teeth 62a and 62b are arranged alternately at equal angular intervals in the circumferential direction. For example, the B-phase stack 62 has 12 pole teeth 62a and 12 pole teeth 62b. The angle between adjacent pole teeth 62a and pole teeth 62b is 15 degrees. The B-phase stack 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 opposite polarity. The B-phase stack 62 has the same configuration as the A-phase stack 61.

[0041] The A-phase stack 61 is coaxially positioned on top of the B-phase stack 62. The B-phase stack 62 is positioned α degrees around the axis L relative to the A-phase stack 61 from a position where the pole teeth 61a and 62a are aligned in the direction of the axis L. α is half the angle between the pole teeth 61a and 61b, which in this embodiment is 7.5 degrees.

[0042] A can 20 is positioned inside the stator 60. A rotor 41 is positioned inside the can 20. The stator 60 and rotor 41 are a stepping motor 66. The stepping motor 66 is connected to an electric valve control device 70.

[0043] In this embodiment, the stepping motor 66 is controlled using a two-phase excitation method. The rotor 41 rotates when pulses P (P[1] to P[4]) are input to the stepping motor 66. Specifically, the rotor 41 rotates when a drive current I corresponding to the pulses P is supplied to the stator 60 of the stepping motor 66. In this specification, "pulses P being input to the stepping motor 66" is synonymous with "a drive current I corresponding to the pulses P being supplied to the stator 60 of the stepping motor 66". The stepping motor 66 may also be controlled using a one-phase excitation method, a one-to-two-phase excitation method, a W1-to-two-phase excitation method, a 2W1-to-two-phase excitation method, or a 4W1-to-two-phase excitation method.

[0044] When pulses P are cyclically input to the stepping motor 66 in ascending order (the order of pulses P[1] to P[4]), the rotor 41 rotates in a first direction (clockwise direction in FIG. 3). When pulses P are cyclically input to the stepping motor 66 in descending order (the order of pulses P[4] to P[1]), the rotor 41 rotates in a second direction (counterclockwise direction in FIG. 3).

[0045] FIGS. 4 to 7 schematically show the positional relationship between the magnetic poles of the rotor 41 and the pole teeth of the stator 60 when pulses P[1] to P[4] are input to the stepping motor 66. In FIGS. 4 to 7, the magnetic poles of the rotor 41 and the stator 60 are schematically shown. In FIGS. 4 to 7, in order to make it easy to grasp the positional relationship between the rotor 41 and the stator 60 (the A-phase stack 61 and the B-phase stack 62), black circles are added to the reference pole teeth 61a and the reference magnetic pole (S pole) of the rotor 41.

[0046] 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 valve shaft holder 42 move downward by the feed screw action between the female screw 42c of the valve shaft holder 42 and the male screw 43c of the guide bush 43. The valve shaft holder 42 pushes the valve body 30 downward via the valve-closing spring 47. The valve body 30 moves downward so that the valve portion 33 comes into contact with the valve seat 18. The position of the rotor 41 at this time is 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 valve shaft holder 42 move further downward. The valve body 30 does not move downward. Then, when the movable stopper 42s comes into contact with the fixed stopper 44s, the rotation of the rotor 41 in the first direction is restricted. The position of the rotor 41 at this time is 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 at the reference position Rx.

[0047] 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 shaft holder 42 are moved upward by the feed screw action between the female screw 42c of the valve shaft holder 42 and the male screw 43c of the guide bush 43. The valve shaft holder 42 pushes the retaining member 45 upward. The valve body 30 moves upward together with the retaining member 45, so that the valve body 30 separates from the valve seat 18. In a predetermined flow measurement environment, the position of the rotor 41 when the flow rate of fluid at the valve port 17 (the opening degree of the valve port 17) is a predetermined set value is defined as the valve opening position Ro. The set value is appropriately set according to the configuration, application, and other factors 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 body 30 is farthest from the valve port 17, and the valve port 17 reaches the maximum opening degree.

[0048] The number of pulses P for rotating the rotor 41 from the fully open position Rz to the reference position Rx is referred to as the stroke number Ns. That is, when pulses of the stroke number Ns are input to the stepping motor 66 of the motor-operated valve 5 with the rotor 41 located at the fully open position Rz, the rotor 41 moves to the reference position Rx. For example, the stroke number Ns is 500.

[0049] In the motor-operated valve 5, the respective central axes of the valve port 17, the valve seat 18, the can 20, the valve body 30, the rotor 41, the valve shaft holder 42, the guide bush 43, and the stator 60 (the A-phase stack 61 and the B-phase stack 62) coincide with the axis L.

[0050] The motor-operated valve control device 70 has a substrate 71 on which a plurality of electronic components (not shown) are mounted. As shown in FIG. 1, the motor-operated valve control device 70 includes a non-volatile memory 75, a communication device 76, a motor driver 77, 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.

[0051] The non-volatile memory 75 stores data that needs to be retained even when the power supply is cut off. For example, the non-volatile memory 75 stores the position of the rotor 41 immediately before the power supply to the motor-operated valve control device 70 is cut off. The non-volatile memory 75 is an EEPROM, a flash memory, or the like.

[0052] The communication device 76 is connected to the air conditioner control device 110 via a wired communication bus 120 so as to be able to communicate. The air conditioner 100 employs a communication method such as Local Interconnect Network (LIN) or 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.

[0053] Figure 8 is a schematic diagram showing the computer 80, motor driver 77, and stepping motor 66 of the electric valve control device 70. The motor driver 77 is connected to the stepping motor 66 (A-phase coil 61c and B-phase coil 62c) and the computer 80.

[0054] The motor driver 77 is controlled by the computer 80. The motor driver 77 supplies a drive current I to the coils of the stator 60 to rotate the rotor 41. Specifically, 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. The A-phase current Ia and the B-phase current Ib are the drive current I.

[0055] The motor driver 77 receives step signals (STEP) and direction signals (DIR) from the computer 80. The step signal is a pulse signal. When the motor driver 77 receives a direction signal corresponding to the first direction (e.g., an H-level signal), the input of a step signal corresponds to the input of pulses P to the stepping motor 66 in ascending order. When the motor driver 77 receives a direction signal corresponding to the second direction (e.g., an L-level signal), the input of a step signal corresponds to the input of pulses P to the stepping motor 66 in descending order. Figure 9 schematically shows an example of the relationship between the pulses P input to the stepping motor 66 and the step signals and direction signals input to the motor driver 77.

[0056] Furthermore, the motor driver 77 receives a current control signal (CONTROL) from the computer 80. The current control signal is a signal to set target values ​​for the A-phase current Ia and B-phase current Ib (A-phase current target value and B-phase current target value) in the motor driver 77.

[0057] Figure 10 shows an example of the correspondence between pulse P and the A-phase current target value and the B-phase current target value. For pulse P[1], "+It" is set as the A-phase current target value and "-It" is set as the B-phase current target value. For pulse P[2], "+It" is set as the A-phase current target value and "+It" is set as the B-phase current target value. For pulse P[3], "-It" is set as the A-phase current target value and "+It" is set as the B-phase current target value. For pulse P[4], "-It" is set as the A-phase current target value and "-It" is set as the B-phase current target value. "+It" and "-It" have the same current magnitude but different current directions. The magnitude of the target value (|It|) is, for example, 200mA to 600mA.

[0058] Figure 11 schematically shows examples of 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. The A-phase current Ia and the B-phase current Ib are rectangular wave currents that alternately change between a first current value and a second current value.

[0059] In Figures 10 and 11, 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.

[0060] In this embodiment, the period of pulse P is 8 ms, and one period including pulses P[1] to P[4] is 32 ms. The stepping motor 66 is controlled in a full-step manner. The step angle of the stepping motor 66 is 7.5 degrees. The stepping motor 66 may also be controlled in a half-step manner or a micro-step manner.

[0061] The motor driver 77 includes H-bridge circuits 77A and 77B and a current control unit 77C. The motor driver 77 drives the stepping motor 66 in a bipolar manner.

[0062] H-bridge circuit 77A is connected to the A-phase coil 61c. H-bridge circuit 77A has switches SW11, SW12, SW13, and SW14. The upstream end of H-bridge circuit 77A is connected to the power supply, and the downstream end of H-bridge circuit 77A is connected to the reference potential of the substrate 71 via a shunt resistor 78A. H-bridge circuit 77B is connected to the B-phase coil 62c. H-bridge circuit 77B has switches SW21, SW22, SW23, and SW24. The upstream end of H-bridge circuit 77B is connected to the power supply, and the downstream end of H-bridge circuit 77B is connected to the reference potential of the substrate 71 via a shunt resistor 78B. Switches SW11, SW12, SW13, SW14 and switches SW21, SW22, SW23, SW24 are, for example, N-channel MOSFETs or P-channel MOSFETs, and both may be mixed.

[0063] Switches SW11, SW12, SW13, SW14 and SW21, SW22, SW23, SW24 are controlled to be on (conductive) or off (non-conductive).

[0064] The current control unit 77C controls the H-bridge circuits 77A and 77B using pulse width modulation (PWM) in response to step signals and direction signals from the computer 80. In this embodiment, the PWM frequency is 20 kHz.

[0065] When supplying the A-phase current Ia from terminal A1 to terminal A2 to the A-phase coil 61c: (1) The current control unit 77C turns off switches SW12 and SW13. (2) The current control unit 77C controls the ON time (i.e., duty cycle) of 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.

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

[0067] When supplying a B-phase current Ib to the B-phase coil 62c, flowing from terminal B1 to terminal B2: (1) The current control unit 77C turns off switches SW22 and SW23. (2) The current control unit 77C controls the ON time of switches SW21 and SW24 so that the magnitude of the B-phase current Ib is the same as the magnitude of the B-phase current target value.

[0068] When supplying a B-phase current Ib to the B-phase coil 62c, flowing from terminal B2 to terminal B1: (1) The current control unit 77C turns off switches SW21 and SW24. (2) The current control unit 77C controls the ON time of 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.

[0069] The A-phase current Ia and B-phase current Ib are currents controlled by pulse width modulation. Each switch is turned on / off at time intervals shorter than the pulse P period so that the A-phase current Ia and B-phase current Ib reach their respective target values.

[0070] Computer 80 is a microcomputer for embedded devices, in which a CPU, ROM, RAM, analog-to-digital converter (ADC), etc., are integrated into a single package. Computer 80 may also include non-volatile memory 75, a communication device 76, and a motor driver 77. Computer 80 is a processing unit.

[0071] Computer 80 has output ports OP1 and OP2. Output ports OP1 and OP2 are connected to the motor driver 77. Computer 80 outputs step signals and direction signals from output ports OP1 and OP2. Computer 80 has a communication port COM. Communication port COM is connected to the motor driver 77. Computer 80 outputs a current control signal from communication port COM. Information provided by the motor driver 77 is input to computer 80 from communication port COM.

[0072] Computer 80 has input ports IP1 and IP2. Input ports IP1 and IP2 are connected to the downstream ends of H-bridge circuits 77A and 77B. The voltage input to input port IP1 is converted by the ADC into information indicating the A-phase current Ia flowing through the A-phase coil 61c. The voltage input to input port IP2 is converted by the ADC into information indicating the B-phase current Ib flowing through the B-phase coil 62c. Computer 80 (CPU) acquires the information converted by the ADC as the A-phase current Ia and the B-phase current Ib.

[0073] The computer 80 functions as a rotation control unit 81, an acquisition unit 82, and a determination unit 83 by having the CPU execute a program stored in ROM.

[0074] The rotation control unit 81 inputs a pulse P to the stepping motor 66 to rotate the rotor 41 in the first or second direction. Specifically, the rotation control unit 81 controls the motor driver 77 based on commands from the air conditioner control device 110, supplying 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.

[0075] The acquisition unit 82 acquires change amount information F. The change amount information F is information relating to the amount of change C of the drive current I in the stator 60 during the determination interval D of the change period T until the drive current I flowing through the coil of the stator 60 changes from a first current value to a second current value. The drive current I is the A-phase current Ia, the B-phase current Ib, or the A-phase current Ia and the B-phase current Ib.

[0076] When the first current value is "-It" and the second current value is "+It", the change period T is the rise period rt of the drive current I. When the first current value is "+It" and the second current value is "-It", the change period T is the fall period ft of the drive current I. Either the rise period rt or the fall period ft may be used as the change period T. The determination interval D is a part of the change period T. The start of the determination interval D may be the same as the start of the change period T, or it may be later than the start of the change period T. In the determination interval D, the drive current I increases or decreases monotonically. The determination interval D is set appropriately according to the configuration of the electric valve 5.

[0077] The acquisition unit 82 acquires the drive current I via the ADC and calculates the change amount C of the drive current I in the determination interval D of the change period T. The change amount C of the drive current I indicates the amount (absolute value) of the change in the drive current I, and specifically, it is the difference between the value of the drive current I at the start of the determination interval D and the value of the drive current I at the end of the determination interval D. When the acquisition unit 82 calculates multiple change amounts C of the drive current I, it acquires their average value A or the variation amount V. The variation amount V is, for example, the standard deviation of the multiple change amounts C of the drive current I, or the difference between the maximum and minimum values ​​of the multiple change amounts C of the drive current I. The acquisition unit 82 acquires at least one of the average value A and the variation amount V as change amount information F.

[0078] The determination unit 83 determines the state of the electric valve 5 using the change amount information F acquired by the acquisition unit 82. The electric valve 5 has a rotation-permitted state Sp, a first-direction rotation-restricted state Sr, and a fault state Sf.

[0079] The rotation-permitted state Sp is a state in which rotation of the rotor 41 is permitted in both the first and second directions.

[0080] The first-direction rotation restriction state Sr is a state in which the rotor 41 has reached the reference position Rx and the movable stopper 42s has come into contact with the fixed stopper 44s, thereby restricting the rotation of the rotor 41 in the first direction. In the first-direction rotation restriction state Sr, the rotor 41 is at the reference position Rx. In the first-direction rotation restriction state Sr, the rotation of the rotor 41 in the second direction is not restricted.

[0081] Fault condition Sf is a condition in which a malfunction of the electric valve 5 is suspected. For example, when foreign matter contained in the refrigerant enters the drive mechanism 40, or when the viscosity of the refrigerant oil in the refrigerant increases at low temperatures, preventing the rotor 41 from rotating normally, the electric valve 5 is determined to be in fault condition Sf. Fault condition Sf includes rotational restraint condition Sc. Rotational restraint condition Sc is a condition in which the rotation of the rotor 41 in the first and second directions is restricted.

[0082] The inventors supplied a drive current I to the coil of the stator 60 of the electric valve 5 and observed the waveform of the drive current I flowing through the coil. Figure 12 shows an example of the waveform of the drive current I flowing through the coil. In Figure 12, the waveform of the drive current I measured when the electric valve 5 is in the rotation-permitted state Sp and the waveform of the drive current I measured when the electric valve 5 is in the first-direction rotation-restricted state Sr are superimposed. In Figure 12, time progresses from left to right.

[0083] As shown in Figure 12, the waveform of the drive current I when the electric valve 5 is in the first-direction rotation restricted state Sr reaches the target value faster than the waveform of the drive current I when the electric valve 5 is in the rotation-allowed state Sp. Although not shown, the waveform of the drive current I when the electric valve 5 is in the rotation-constrained state Sc also reaches the target value faster than the waveform of the drive current I when the electric valve 5 is in the rotation-allowed state Sp. In other words, the rise time rt when the electric valve 5 is in the first-direction rotation restricted state Sr (or rotation-constrained state Sc) is shorter than the rise time rt when the electric valve 5 is in the rotation-allowed state Sp. The fall time ft when the electric valve 5 is in the first-direction rotation restricted state Sr (or rotation-constrained state Sc) is shorter than the fall time ft when the electric valve 5 is in the rotation-allowed state Sp. Figure 13 shows the rise time rt and fall time ft.

[0084] Figure 14 shows an example of the change in drive current I C in the determination interval D of the change period T when the electric valve 5 is in the rotation-allowed state Sp. Figure 15 shows an example of the change in drive current I C in the determination interval D of the change period T when the electric valve 5 is in the first-direction rotation-restricted state Sr. In Figures 14 and 15, the change period T is the rise period rt. The length from the start of the change period T to the start of the determination interval D is constant regardless of the length of the change period T. The length of the determination interval D is constant regardless of the length of the change period T. As shown in Figures 14 and 15, the change in drive current I C when the electric valve 5 is in the first-direction rotation-restricted state Sr is greater than the change in drive current I C when the electric valve 5 is in the rotation-allowed state Sp. Even when the change period T is the fall period ft, the change in drive current I C when the electric valve 5 is in the first-direction rotation-restricted state Sr is greater than the change in drive current I C when the electric valve 5 is in the rotation-allowed state Sp.

[0085] Next, the inventors measured the change in drive current I C in the determination interval D of the change period T. Figures 16 and 17 show examples of the change in drive current I C measured over time. In Figure 16, before time Tx, the electric valve 5 is in a rotation-allowed state Sp, and after time Tx, the electric valve 5 is in a first-direction rotation-restricted state Sr. In Figure 17, before time Tx, the electric valve 5 is in a rotation-allowed state Sp, and after time Tx, the electric valve 5 is in a rotation-restricted state Sc. Each black dot corresponds to the change in drive current I C.

[0086] As shown in Figures 16 and 17, when the electric valve 5 is in the rotation-permitted state Sp, the change in the drive current I C is small and the difference between the maximum and minimum values ​​is small. When the electric valve 5 is in the first-direction rotation-restricted state Sr, the change in the drive current I C is large and the difference between the maximum and minimum values ​​is large. When the electric valve 5 is in the rotation-restricted state Sc, the change in the drive current I C is large and the difference between the maximum and minimum values ​​is very small. In other words, when the electric valve 5 is in the rotation-permitted state Sp, the average value A of the change in the drive current I C is small and the variation V is small. When the electric valve 5 is in the first-direction rotation-restricted state Sr, the average value A of the change in the drive current I C is large and the variation is large. When the electric valve 5 is in the rotation-restricted state Sc, the average value A of the change in the drive current I C is large and the variation V is very small. Therefore, the state of the electric valve 5 can be determined by using at least one of the average value A and the variation V.

[0087] The electric valve control device 70 has two operating modes: an initialization mode and a normal mode. In the initialization mode, the electric valve control device 70 performs an initialization operation to rotate the rotor 41 in the first direction and position it at the reference position Rx. In the normal mode, the electric valve control device 70 performs operations based on control commands received from the air conditioner control device 110.

[0088] When power is turned on, the electric valve control device 70 switches to normal mode and reads the position of the rotor 41 stored in the non-volatile memory 75 as the current position of the rotor 41. When the electric valve control device 70 receives a control command from the air conditioner control device 110, including the target valve opening, it rotates the rotor 41 from its current position to a position corresponding to the target valve opening and sets that position as the new current position. The electric valve control device 70 stores the current position in the non-volatile memory 75 just before the power is cut off. When the electric valve control device 70 receives an initialization command from the air conditioner control device 110, or when there is an abnormality in the position of the rotor 41 read from the non-volatile memory 75, it switches to initialization mode and performs initialization. After performing initialization, the electric valve control device 70 switches back to normal mode.

[0089] Next, a first example of operation of the electric valve control device 70 will be explained with reference to Figure 18.

[0090] The electric valve control device 70 (computer 80) calculates the average value A of multiple changes C of the drive currents I when a drive current I is supplied to the coil of the stator 60 (S110). Specifically, when the rotor 41 is rotating, the electric valve control device 70 obtains the changes C of the drive current I in the determination interval D of the change period T, and after obtaining a predetermined number (for example, 10) of changes C of the drive current I, it calculates their average value A.

[0091] The electric valve control device 70 calculates the difference value Ad between the reference value Ar and the average value A (S120). The difference value Ad is an absolute value. The reference value Ar is set, for example, based on the average value A of the electric valve 5 in the rotation-permitted state Sp. Separate reference values ​​Ar may be provided for use when the rotor 41 is rotating in the first direction and for use when the rotor 41 is rotating in the second direction.

[0092] The electric valve control device 70 determines whether the difference value Ad is greater than or equal to the determination value Ah (S130). The determination value Ah is set, for example, based on the difference between the average value A of the electric valve 5 in the rotation-permitted state Sp and the average value A of the electric valve 5 in the first-direction rotation-restricted state Sr (or rotation-constrained state Sc). Separate determination values ​​Ah may be provided for use when the rotor 41 is rotating in the first direction and for use when the rotor 41 is rotating in the second direction.

[0093] When the difference value Ad is smaller than the determination value Ah (N in S130), the electric valve control device 70 determines that the electric valve 5 is in a rotation-permitted state Sp and returns to calculating the average value A (S110).

[0094] The electric valve control device 70 determines whether or not it is in initialization mode when the difference value Ad is greater than or equal to the determination value Ah (Y in S130) (S180).

[0095] When the electric valve control device 70 is in initialization mode (Y in S180), it determines that the electric valve 5 is in the first-direction rotation restricted state Sr, sets the reference position Rx as the current position of the rotor 41 (S181), and notifies the air conditioner control device 110 that the initialization operation is complete (S182). Then, the electric valve control device 70 stops supplying the drive current I to the coil of the stator 60 and stops the rotation of the rotor 41 (S184).

[0096] When the electric valve control device 70 is not in initialization mode (N in S180), it determines that the electric valve 5 is in a fault state Sf and notifies the air conditioner control device 110 of the electric valve 5's failure (S183). The electric valve control device 70 then stops supplying the drive current I to the stator 60 coil and stops the rotation of the rotor 41 (S184). When the electric valve control device 70 is not in initialization mode, the electric valve control device 70 is in normal mode.

[0097] Next, a second example of operation of the electric valve control device 70 will be explained with reference to Figure 19.

[0098] The electric valve control device 70 (computer 80) calculates the variation amount V of multiple changes C of the drive currents I when a drive current I is supplied to the coil of the stator 60 (S210). Specifically, when the rotor 41 is rotating, the electric valve control device 70 obtains the change amount C of the drive current I in the determination interval D of the change period T, and after obtaining a predetermined number (for example, 10) of change amounts C of the drive current I, it calculates their variation amount V. The variation amount V is the standard deviation of the multiple change amounts C of the drive currents I. The variation amount V may also be the difference between the maximum and minimum values ​​of the multiple change amounts C of the drive currents I.

[0099] The electric valve control device 70 determines whether the variation amount V is greater than or equal to a first determination value Vh1 (S230). The first determination value Vh1 is set, for example, based on the variation amount V in the electric valve 5 in the rotation-permitted state Sp. Separate first determination values ​​Vh1 may be provided for use when the rotor 41 is rotating in the first direction and for use when the rotor 41 is rotating in the second direction.

[0100] When the variation amount V is less than the first determination value Vh1 (N in S230), the electric valve control device 70 determines that the electric valve 5 is in a rotation-permitted state Sp and returns to calculating the variation amount V (S210).

[0101] The electric valve control device 70 determines whether or not it is in initialization mode (S280) when the variation amount V is greater than or equal to the first determination value Vh1 (Y in S230). The operation of steps S280 to S284 is the same as the operation of steps S180 to S184 in Figure 18. The explanation of the operation of steps S280 to S284 is omitted.

[0102] Next, a third example of operation of the electric valve control device 70 will be explained with reference to Figure 20.

[0103] The electric valve control device 70 (computer 80) calculates the average value A of the changes C of multiple drive currents I when a drive current I is supplied to the coil of the stator 60 (S310). The electric valve control device 70 calculates the difference value Ad between the reference value Ar and the average value A (S320). The electric valve control device 70 determines whether the difference value Ad is greater than or equal to the judgment value Ah (S330). The operation of steps S310 to S330 is the same as the operation of steps S110 to S130 in Figure 18.

[0104] When the difference value Ad is smaller than the determination value Ah (N in S330), the electric valve control device 70 determines that the electric valve 5 is in a rotation-permitted state Sp and returns to calculating the average value A (S310).

[0105] The electric valve control device 70 calculates the variation amount V of the changes C of multiple drive currents I when the difference value Ad is greater than or equal to the judgment value Ah (Y in S330) (S340). The operation in step S340 is the same as the operation in step S210 in Figure 19. The electric valve control device 70 may calculate the variation amount V of the newly acquired changes C of multiple drive currents I, or it may calculate the variation amount V of the changes C of multiple drive currents I used to calculate the average value A.

[0106] The electric valve control device 70 determines whether the variation amount V is less than or equal to the second determination value Vh2 (S350). The second determination value Vh2 is set, for example, based on the variation amount V in the electric valve 5 in the rotation-allowed state Sp (or rotation-restricted state Sc). Separate second determination values ​​Vh2 may be provided for use when the rotor 41 is rotating in the first direction and for use when the rotor 41 is rotating in the second direction.

[0107] The electric valve control device 70 determines that the electric valve 5 is in a faulty state Sf (rotationally constrained state Sc) when the variation amount V is less than or equal to the second determination value Vh2 (Y in S350), and proceeds to step S383.

[0108] The electric valve control device 70 determines whether the variation amount V is greater than or equal to the first determination value Vh1 (S360) when the variation amount V is greater than the second determination value Vh2 (N in S350). The first determination value Vh1 is set, for example, based on the variation amount V in the electric valve 5 in the rotation-permitted state Sp (or the first-direction rotation-restricted state Sr). Separate first determination values ​​Vh1 may be provided for use when the rotor 41 is rotating in the first direction and for use when the rotor 41 is rotating in the second direction. The second determination value Vh2 is less than the first determination value Vh1.

[0109] When the variation amount V is less than the first determination value Vh1 (N in S360), the electric valve control device 70 determines that the electric valve 5 is in a rotation-permitted state Sp and returns to calculating the average value A (S310).

[0110] The electric valve control device 70 determines whether or not it is in initialization mode (S380) when the variation amount V is greater than or equal to the first determination value Vh1 (Y in S360). The operation of steps S380 to S384 is the same as the operation of steps S180 to S184 in Figure 18. The explanation of the operation of steps S380 to S384 is omitted.

[0111] In the first to third operation examples, the electric valve control device 70 may use the A-phase current Ia, the B-phase current Ib, or both as the drive current I. The electric valve control device 70 may use the rise period rt, the fall period ft, or both as the change period T of the drive current I.

[0112] Furthermore, the electric valve control device 70 sets the determination interval D of the change period T using a time calculated based on the reference change period Tr. For example, the shortest change period T when the electric valve 5 is in the first direction rotation restricted state Sr or rotation restrained state Sc is defined as the reference change period Tr. If the start of the reference change period Tr is set to 0% and the end to 100%, the electric valve control device 70 uses, for example, the interval corresponding to the interval from 10% to 50% of the reference change period Tr in the change period T as the determination interval D of the change period T. If the start of the reference change period Tr is set to T0, the point in time when the reference change period Tr is 10% is set to T10, and the point in time when the reference change period Tr is 50% is set to T50, the electric valve control device 70 defines the interval from the start of the change period T to the point in time when T10 has elapsed to the point in time when T50 has elapsed as the determination interval D. Note that the start of the determination interval D may be the same as the start of the reference change period Tr. In this way, near the start of the change period T, the amount of change in the drive current I per unit time varies relatively large for each state of the electric valve 5, allowing for a more accurate determination of the state of the electric valve 5.

[0113] Furthermore, the reference value Ar, the judgment value Ah, the first judgment value Vh1, and the second judgment value Vh2 are stored in the non-volatile memory 75 during the manufacture of the electric valve device 1. The electric valve control device 70 may, for example, set (update) the reference value Ar, the judgment value Ah, the first judgment value Vh1, and the second judgment value Vh2 in response to a command from the air conditioner control device 110.

[0114] As described above, the electric valve device 1 includes an electric valve 5 and an electric valve control device 70. The electric valve 5 includes a valve body 10 having a valve port 17, a rotor 41, a stator 60 equipped with a coil to which a drive current I for rotating the rotor 41 is supplied, and a valve body 30 that moves relative to the valve port 17 when the rotor 41 rotates. The electric valve control device 70 has a computer 80 that determines whether or not the rotation of the rotor 41 is restricted using information (change amount information F) related to the amount of change C of the drive current I in the determination interval D of the change period T until the drive current I flowing through the coil changes from a first current value to a second current value. In this way, the electric valve control device 70 can determine whether or not the rotation of the rotor 41 is restricted even if a drive current I is supplied to the coil.

[0115] Furthermore, the change amount information F is the average value A of the change amount C of the drive current I (first operation example), the variation amount V of the change amount C of the drive current I (second operation example), or the average value A and the variation amount V (third operation example). In this way, the electric valve control device 70 can determine whether or not the rotation of the rotor 41 is restricted based on information that can be obtained relatively easily.

[0116] Furthermore, the electric valve 5 has 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. The computer 80 determines that the rotation of the rotor 41 in the first direction is restricted by the stopper mechanism 49 (first direction rotation restriction state Sr) when the variation amount V is greater than or equal to a first determination value Vh1 when the rotor 41 is rotating in the first direction in the initialization mode (second operation example and third operation example). In this way, the electric valve control device 70 can determine the state of the electric valve 5 in more detail.

[0117] Furthermore, when the variation amount V is less than or equal to a second determination value Vh2, which is smaller than the first determination value Vh1, the computer 80 determines that the rotation of the rotor 41 in the first and second directions is restricted (rotational constraint state Sc) (third operation example). In this way, the electric valve control device 70 can determine the state of the electric valve 5 in more detail.

[0118] In this specification, terms indicating shapes such as "cylinder" and "column" are also used to refer to members or parts of members that substantially have the shape of those terms. For example, "cylindrical member" includes both cylindrical members and substantially cylindrical members. Furthermore, in this specification, the term "same" may include both strictly identical and substantially identical items.

[0119] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, deletions, design modifications, and combinations of features of the embodiments, as appropriate by those skilled in the art, are also included within the scope of the present invention, as long as they do not contradict the spirit of the invention.

[0120] 1...Electric valve device, 5...Electric valve, 10...Valve body, 11...Body component, 13...Connecting component, 14...Valve chamber, 17...Valve port, 18...Valve seat, 20...Can, 30...Valve body, 40...Drive mechanism, 41...Rotor, 42...Valve shaft holder, 42c...Female thread, 42s...Movable stopper, 43...Guide bush, 43c...Male thread, 44...Stopper component, 44s...Fixed stopper, 49...Stopper mechanism, 60...Stator, 61...A-phase stack, 61c...A-phase coil, 62...B-phase stack, 62c...B-phase coil, 66...Stepping motor, 70...Electric valve control device, 75...Non-volatile memory, 76...Communication device, 77...Motor driver, 80...Computer

Claims

1. An electric valve control device for controlling an electric valve having a valve body having a valve port, a rotor, a stator equipped with a coil to which a drive current for rotating the rotor is supplied, and a valve body that moves relative to the valve port when the rotor rotates, the electric valve control device comprising a processing device that determines whether or not the rotation of the rotor is restricted using information relating to the amount of change of the drive current in a part of the change period from a first current value to a second current value in which the drive current flowing through the coil changes.

2. The electric valve control device according to claim 1, wherein the start time of the partial section is the same as the start time of the change period.

3. The electric valve control device according to claim 1, wherein the information includes the average value of the change in the drive current.

4. The electric valve control device according to claim 1, wherein the information includes the amount of variation in the amount of change of the drive current.

5. The electric valve control device according to claim 4, wherein the electric valve has a stopper mechanism that restricts the rotation of the rotor in a first direction when the rotor is in a reference position, and the processing device determines that the rotation of the rotor in the first direction is restricted by the stopper mechanism when the amount of variation is greater than or equal to a first determination value when the rotor is rotating in the first direction.

6. The electric valve control device according to claim 5, wherein the processing device determines that the rotation of the rotor in the first and second directions is restricted when the amount of variation is less than or equal to a second determination value which is less than the first determination value.

7. An electric valve device comprising an electric valve control device according to any one of claims 1 to 6, and the electric valve.

8. A method for determining the state of an electric valve, comprising a valve body having a valve port, a rotor, a stator equipped with a coil to which a drive current for rotating the rotor is supplied, and a valve body that moves relative to the valve port when the rotor rotates, characterized in that the method determines whether or not the rotation of the rotor is restricted using information relating to the amount of change of the drive current in a part of the change period from a first current value to a second current value in which the drive current flowing through the coil changes.

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