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 the rotation of a rotor of a stepping motor is being regulated even when a driving current is flowing in a coil of the stepping motor; an electric valve device; and an electric valve state determination method. [Solution] A computer 80 of this electric valve control device determines whether the rotation of a rotor 41 of a stepping motor 66 is being regulated by using information related to a rise period in which the driving current flowing through an A-phase coil 61c of the stepping motor 66 changes from a first current value to a second current value.

Description

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

[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.

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

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

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

[0005] Patent No. 7254400

[0006] The motor-operated valve control device controls the stepping motor using a 1-2 phase excitation method. The 1-2 phase excitation method has a 2-phase excitation period and a 1-phase excitation period. During the 2-phase excitation period, a drive current is supplied to both the A-phase coil and the B-phase coil. During the 1-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 rotor rotation, 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 rotor rotation, making it difficult for the motor-operated valve control device to obtain only the voltage generated in the coil due to the rotor rotation.

[0008] During the one-phase excitation period, when a drive current is supplied only to the A-phase coil, the voltage generated in the B-phase coil contains only a voltage component generated by the rotation of the rotor, and when a drive current is supplied only to the B-phase coil, the voltage generated in the A-phase coil contains only a voltage component generated by the rotation of the rotor.The motor-operated valve control device can obtain the voltage generated in the A-phase coil or the B-phase coil to which no drive current is supplied as the voltage generated by the rotation of the rotor.

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

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

[0011] Therefore, an object of the present invention is to provide an electric valve control device, an electric valve device, and a method for determining the state of an electric valve that can determine whether rotor rotation is restricted even when a driving current is supplied to the stator coil.

[0012] The inventors conducted extensive research using multiple motor-operated valves, supplying a drive current to the stator coil and measuring the drive current flowing through the coil, and discovered that there is a difference in the waveform of the drive current during the change period from a first current value to a second current value in a motor-operated valve in which rotor rotation is restricted, and the waveform during the change period in a motor-operated valve in which rotor rotation is not restricted, leading to the present invention.

[0013] 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 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 rotation of the rotor is restricted using information related to the change period until the drive current flowing through the coil changes from a first current value to a second current value.

[0014] In the present invention, it is preferable that the information relating to the change period is a change time from the start to the end of the change period.

[0015] In the present invention, it is preferable that the information relating to the change period is an average value of the change time.

[0016] In the present invention, it is preferable that the information relating to the change period is an amount of variation in the change time.

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

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

[0019] In the present invention, it is preferable that the drive current is controlled by pulse width modulation, and the information relating to the change period is a duty cycle of the pulse width modulation in a determination period that includes the change period.

[0020] In the present invention, it is preferable that the information relating to the change period is a waveform of the drive current flowing through the coil during a determination period that includes the change period.

[0021] 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.

[0022] In order to achieve the above object, another aspect of the present invention provides a state determination method for an electric valve having a valve body with 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 it determines whether or not rotation of the rotor is restricted using information related to the change period until the drive current flowing through the coil changes from a first current value to a second current value.

[0023] According to the present invention, whether or not rotor rotation is restricted is determined using information related to the change period during which the drive current flowing through the stator coil changes from the first current value to the second current value, making it possible to determine whether or not rotor rotation is restricted even when the drive current is supplied to the stator coil.

[0024] 1 is a block diagram of an air conditioner having an electric valve device;

[0023] FIG. 1 is a cross-sectional view of the electric valve device;

[0024] FIG. 2 is a plan view of the valve stem holder, stopper member, rotor, and stator of the electric valve device;

[0025] FIG. 3 is a schematic diagram showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[1] is input);

[0026] FIG. 4 is a schematic diagram showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[2] is input);

[0027] FIG. 5 is a schematic diagram showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[3] is input);

[0028] FIG. 6 is a schematic diagram showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[4] is input).

[0029] FIG. 7 is a schematic diagram showing a computer, a motor driver, and a stepping motor included in an electric valve control device of the electric valve device;

[0029] FIG. 8 is a diagram showing an example of the relationship between pulses input to the stepping motor and step signals and direction signals input to the motor driver;

[0029] FIG. 9 is a diagram showing an example of the correspondence relationship between pulses and A-phase current target values ​​and B-phase current target values;

[0029] FIG. 10 is a diagram showing an example of the waveforms of A-phase current and B-phase current. 1 is a diagram showing an example of the waveform of a drive current flowing through a stator coil. FIG. 2 is a diagram schematically showing the waveform of a drive current flowing through a stator coil. FIG. 3 is a diagram showing an example of the relationship between the rise time of the drive current waveform and the state of the motor-operated valve. FIG. 4 is a diagram showing another example of the relationship between the rise time of the drive current waveform and the state of the motor-operated valve. FIG. 5 is a diagram schematically showing an example of the relationship between the drive current waveform and the duty cycle (state in which rotor rotation is permitted). FIG. 6 is a diagram schematically showing another example of the relationship between the drive current waveform and the duty cycle. FIG. 7 is a diagram schematically showing two drive current waveforms (state in which rotor rotation is restricted). FIG. 8 is a flowchart showing a first operation example of the motor-operated valve control device. FIG. 9 is a flowchart showing a second operation example of the motor-operated valve control device. FIG. 10 is a flowchart showing a third operation example of the motor-operated valve control device. FIG. 11 is a flowchart showing a fourth operation example of the motor-operated valve control device. FIG. 12 is a flowchart showing a fifth operation example of the motor-operated valve control device. FIG. 13 is a diagram showing an example of a data table of reference waveforms of drive current.

[0025] Hereinafter, an electric valve device according to one embodiment of the present invention will be described.

[0026] The motor-operated 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 for controlling the flow rate of a refrigerant. The motor-operated valve device 1 has a motor-operated valve 5 and a motor-operated valve control device 70. Fig. 1 shows a block diagram of an air conditioner 100 having the motor-operated valve device 1. Fig. 2 shows a cross-sectional view of the motor-operated valve device 1.

[0027] The air conditioner 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 conditioner 100 has an air conditioner control device 110. The air conditioner 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 conditioner control device 110 uses the electric valve device 1 to control the flow rate of refrigerant flowing through the piping 105.

[0028] 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 .

[0029] 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 has a valve chamber 14 and a valve port 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 port 17. The main body member 11 has an annular valve seat 18 that surrounds the valve port 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 that communicates with 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 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.

[0030] 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.

[0031] 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 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 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.

[0032] 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 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.

[0033] Fig. 3 shows a plan view of the rotor 41, the valve stem holder 42, the stopper member 44, and the stator 60. Fig. 3 also shows a schematic representation of the magnetic poles of the rotor 41 and the stator 60. In Fig. 3, the radially outer side of the figure shown as the stator 60 corresponds to the upper side of the stator 60, and the radially inner side corresponds to the lower side.

[0034] 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 alternately disposed 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. The position of the rotor 41 is related to the opening degree of the valve port 17.

[0035] 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 an axial 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 formed on the outer circumferential surface of the valve stem holder 42. The second axial portion 32 of the valve element 30 is disposed in the axial hole 42b, and the second axial portion 32 is movable up and down within the axial hole 42b. A valve-closing spring 47 is disposed between a washer 46 disposed on the lower surface of the upper wall portion 42a of the valve stem holder 42 and the step portion 34 of the valve element 30. The valve-closing spring 47 is a coil spring and presses the valve element 30 toward the valve seat 18. A female thread 42c is formed on the inner circumferential surface of the valve stem holder 42. The movable stopper 42s is fixed to the rotor 41.

[0036] 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 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 direction of the axis L.

[0037] 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.

[0038] The retaining member 45 has a fixed portion 45a and a flange portion 45b. The fixed portion 45a has a stepped cylindrical shape. The second shaft portion 32 of the valve body 30 is disposed inside the fixed portion 45a. The fixed portion 45a is joined to the second shaft portion 32. The flange portion 45b is connected to the lower end of the fixed portion 45a. A return spring 48 is disposed outside the retaining member 45. The return spring 48 is a coil spring.

[0039] The motor-operated valve 5 has a drive mechanism 40 that uses the rotation of the rotor 41 without reducing the speed. 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, instead of the drive mechanism 40.

[0040] The stator 60 has a cylindrical shape and includes an A-phase stack 61 and a B-phase stack 62 .

[0041] The A-phase stack 61 has a plurality of claw-pole-type 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 stack 61 has, for example, 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 the pole teeth 61b become magnetic poles of opposite polarities.

[0042] The B-phase stack 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 stack 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 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 polarities. The B-phase stack 62 has the same configuration as the A-phase stack 61.

[0043] The A-phase stack 61 is coaxially disposed on the B-phase stack 62. The B-phase stack 62 is located at a position rotated 7.5 degrees around the axis L with respect to the A-phase stack 61 from the position where the pole teeth 61 a and the pole teeth 62 a are aligned in the direction of the axis L.

[0044] 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.

[0045] In this embodiment, the stepping motor 66 is controlled by a two-phase excitation method. Pulses P (P[1] to P[4]) are input to the stepping motor 66, causing the rotor 41 to rotate. Specifically, a drive current corresponding to the pulses P is supplied to the stator 60 of the stepping motor 66, causing the rotor 41 to rotate. In this specification, "inputting 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." Note that the stepping motor 66 may also be controlled by a one-phase excitation method, a one-two-phase excitation method, a W1-2-phase excitation method, a two-phase excitation method, or a four-phase excitation method.

[0046] When pulses P are cyclically input to the stepping motor 66 in ascending order (in the order of pulses P[1] to P[4]), the rotor 41 rotates in a first direction (clockwise in FIG. 3). When pulses P are cyclically input to the stepping motor 66 in descending order (in the order of pulses P[4] to P[1]), the rotor 41 rotates in a second direction (counterclockwise in FIG. 3).

[0047] 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. The magnetic poles of the rotor 41 and the stator 60 are also shown in FIGS. 4 to 7. In FIGS. 4 to 7, to make it easier to understand the positional relationship between the rotor 41 and the stator 60 (the A-phase stack 61 and the B-phase stack 62), the reference pole tooth 61a and the reference magnetic pole (south pole) of the rotor 41 are indicated by black circles.

[0048] 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 stem holder 42 move downward 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 presses the valve element 30 downward via the valve closing spring 47. The valve element 30 moves downward, and the valve portion 33 contacts the valve seat 18. The rotor 41 is in the valve closing position Rc at this time. 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 stem holder 42 move further downward. The valve element 30 does not move downward. When the movable stopper 42s contacts the fixed stopper 44s, rotation of the rotor 41 in the first direction is restricted. The rotor 41 is in the reference position Rx at this time. The movable stopper 42s and the fixed stopper 44s form 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.

[0049] 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 retaining member 45 upward. The valve disc 30 moves upward together with the retaining member 45, and the valve disc 30 separates 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.

[0050] The number of pulses P required to rotate 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 P with the stroke number Ns are input to the stepping motor 66 of the motor-operated valve 5 with the rotor 41 in the fully open position Rz, the rotor 41 moves to the reference position Rx. For example, the stroke number Ns is 500.

[0051] In the electric valve 5, the valve port 17, valve seat 18, can 20, valve body 30, rotor 41, valve shaft holder 42, guide bush 43, and stator 60 (A-phase stack 61 and B-phase stack 62) each have a central axis that coincides with the axis L.

[0052] 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 has 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.

[0053] The nonvolatile memory 75 stores data that needs to be retained even when power is cut off. For example, the position of the rotor 41 immediately before power to the motor-operated valve control device 70 is stored in the nonvolatile memory 75. The nonvolatile memory 75 is an EEPROM, a flash memory, or the like.

[0054] The communication device 76 is communicably connected to the air conditioner control device 110 via a wired communication bus 120. 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 wirelessly.

[0055] 8 is a diagram schematically showing a computer 80, a motor driver 77, and a stepping motor 66 included in the electrically operated valve control device 70. The motor driver 77 is connected to the stepping motor 66 (the A-phase coil 61c and the B-phase coil 62c) and the computer 80.

[0056] The motor driver 77 is controlled by the computer 80. The motor driver 77 supplies a drive current to the stator 60 for rotating the rotor 41. 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.

[0057] The motor driver 77 receives a step signal (STEP) and a direction signal (DIR) from the computer 80. The step signal is a pulse signal. When a direction signal corresponding to a first direction (e.g., an H-level signal) is input to the motor driver 77, the step signal is input, which corresponds to pulses P being input to the stepping motor 66 in ascending order. When a direction signal corresponding to a second direction (e.g., an L-level signal) is input to the motor driver 77, the step signal is input, which corresponds to pulses P being input to the stepping motor 66 in descending order. FIG. 9 schematically shows an example of the relationship between the pulses P input to the stepping motor 66 and the step signal and direction signal input to the motor driver 77.

[0058] Furthermore, 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 target values ​​of the A-phase current Ia and the B-phase current Ib (A-phase current target value and B-phase current target value) in the motor driver 77.

[0059] FIG. 10 shows an example of the correspondence between pulse P and the A-phase current target value and 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, 200 to 600 mA.

[0060] 11 shows an example of the waveforms of the A-phase current Ia and the B-phase current Ib when pulses P are input in ascending order to the stepping motor 66. The A-phase current Ia and the B-phase current Ib are rectangular wave currents that alternate between a first current value and a second current value.

[0061] 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.

[0062] 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 using a full-step method. The step angle of the stepping motor 66 is 7.5 degrees. The stepping motor 66 may also be controlled using a half-step method or a micro-step method.

[0063] The motor driver 77 has H-bridge circuits 77 A and 77 B and a current control section 77 C. The motor driver 77 drives the stepping motor 66 in a bipolar manner.

[0064] The H-bridge circuit 77A is connected to the A-phase coil 61c. The H-bridge circuit 77A includes switches SW11, SW12, SW13, and SW14. The upstream end of the H-bridge circuit 77A is connected to a power supply, and the downstream end of the H-bridge circuit 77A is connected to the reference potential of the circuit board 71 via a shunt resistor 78A. The H-bridge circuit 77B is connected to the B-phase coil 62c. The H-bridge circuit 77B includes switches SW21, SW22, SW23, and SW24. The upstream end of the H-bridge circuit 77B is connected to a power supply, and the downstream end of the H-bridge circuit 77B is connected to the reference potential of the circuit board 71 via a shunt resistor 78B. 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 combination of both.

[0065] 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).

[0066] The current control section 77C controls the H-bridge circuits 77A and 77B by 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.

[0067] When supplying the A-phase current Ia flowing from terminal A1 to terminal A2 to the 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 (i.e., 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.

[0068] When supplying the A-phase current Ia flowing from terminal A2 to terminal A1 to the 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 the same as the magnitude of the A-phase current target value.

[0069] When supplying the B-phase current Ib flowing from terminal B1 to terminal B2 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 the same as the magnitude of the B-phase current target value.

[0070] When supplying the B-phase current Ib flowing from terminal B2 to terminal B1 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.

[0071] The A-phase current Ia and the B-phase current Ib are currents controlled by pulse width modulation, in which each switch is turned on and off at a time interval shorter than the period of the pulse P so that the A-phase current Ia and the B-phase current Ib reach their respective target values.

[0072] The computer 80 is a microcomputer for an embedded device in which a CPU, ROM, RAM, an analog-to-digital converter (ADC), etc. are integrated into one package. The computer 80 may include a non-volatile memory 75, a communication device 76, and a motor driver 77. The computer 80 is a processing device.

[0073] The computer 80 has output ports OP1 and OP2. The output ports OP1 and OP2 are connected to the motor driver 77. The computer 80 outputs step signals and direction signals from the output ports OP1 and OP2. The computer 80 has a communication port COM, which is connected to the motor driver 77. The computer 80 outputs a current control signal from the communication port COM. Information provided by the motor driver 77 is input to the computer 80 from the communication port COM.

[0074] The computer 80 has input ports IP1 and IP2. The input ports IP1 and IP2 are connected to the downstream ends of the H-bridge circuits 77A and 77B. The voltage input to the 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 the input port IP2 is converted by the ADC into information indicating the B-phase current Ib flowing through the B-phase coil 62c. The computer 80 (CPU) obtains the information converted by the ADC as the A-phase current Ia and the B-phase current Ib.

[0075] 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.

[0076] 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.

[0077] The acquisition unit 82 acquires information relating to a change period during which the A-phase current Ia flowing through the A-phase coil 61c changes from a first current value to a second current value. The acquisition unit 82 may also acquire information relating to a change period during which the B-phase current Ib flowing through the B-phase coil 62c changes from the first current value to the second current value. Examples of the information relating to the change period are shown below.

[0078] When the first current value is "-It" and the second current value is "+It", the information is: (1) the change time (rise time) from the beginning to the end of the change period (rise period), (2) the average value of multiple rise times, (3) the amount of variation of multiple rise times, (4) the duty cycle in the determination period E including the rise period, or (5) the difference between the waveform of the A-phase current Ia in the determination period E including the rise period and the reference waveform of the A-phase current Ia.

[0079] When the first current value is "+It" and the second current value is "-It", the information is: (6) the change time (fall time) from the start to the end of the change period (fall period), (7) the average value of the plurality of fall times, (8) the amount of variation of the plurality of fall times, (9) the duty cycle in the determination period E including the fall period, or (10) the difference between the waveform of the A-phase current Ia in the determination period E including the fall period and the reference waveform of the A-phase current Ia.

[0080] The acquisition unit 82 acquires information related to the change period based on, for example, the A-phase current Ia and the B-phase current Ib acquired via an ADC. If the motor driver 77 has a function to provide the information (e.g., change time and duty cycle), the acquisition unit 82 may acquire the information from the motor driver 77. The determination period E is equal to or shorter than the length of the period of the pulse P, for example, half the length of the period of the pulse P (4 ms). The start of the determination period E may be the same as the start of the period of the pulse P, or may be later than the start of the period of the pulse P.

[0081] The determination unit 83 determines the state of the motor-operated valve 5 using the information related to the change period acquired by the acquisition unit 82. The motor-operated valve 5 has a rotation permitted state Sp, a first-direction rotation restricted state Sr, and a failure state Sf (including a rotation restricted state Sc).

[0082] The rotation permitted state Sp is a state in which the rotor 41 is permitted to rotate in the first direction and the second direction.

[0083] The first-direction rotation restricted state Sr is a state in which the rotor 41 reaches the reference position Rx, the movable stopper 42s abuts against the fixed stopper 44s, and rotation of the rotor 41 in the first direction is restricted. In the first-direction rotation restricted state Sr, the rotor 41 is at the reference position Rx. In the first-direction rotation restricted state Sr, rotation of the rotor 41 in the second direction is not restricted.

[0084] The fault state Sf is a state in which a fault is suspected in the motor-operated valve 5. For example, when foreign matter contained in the refrigerant enters the drive mechanism 40 or the viscosity of the refrigeration oil in the refrigerant increases at low temperatures, preventing normal rotation of the rotor 41, the motor-operated valve 5 is determined to be in the fault state Sf. The fault state Sf includes a state in which rotation of the rotor 41 in the first direction and the second direction is restricted, and this state is called a rotation restriction state Sc.

[0085] The inventors supplied drive currents (A-phase current Ia and B-phase current Ib) to the coils (A-phase coil 61c and B-phase coil 62c) of the stator 60 of the motor-operated valve 5, and observed the waveforms of the drive currents flowing through the coils. FIG. 12 shows an example of the waveform of the drive current flowing through the coils. In FIG. 12, the waveform of the drive current measured when the motor-operated valve 5 was in the rotation-permitted state Sp is superimposed on the waveform of the drive current measured when the motor-operated valve 5 was in the first-direction rotation-restricted state Sr. In FIG. 12, time progresses from left to right.

[0086] As shown in Figure 12, the waveform of the drive current when the motor-operated valve 5 is in the first-way rotation restricted state Sr reaches the target value earlier than the waveform of the drive current when the motor-operated valve 5 is in the rotation permitted state Sp. Although not shown, the waveform of the drive current when the motor-operated valve 5 is in the rotation restricted state Sc also reaches the target value earlier than the waveform of the drive current when the motor-operated valve 5 is in the rotation permitted state Sp. In other words, the rise time when the motor-operated valve 5 is in the first-way rotation restricted state Sr (or the rotation restricted state Sc) is shorter than the rise time when the motor-operated valve 5 is in the rotation permitted state Sp. The fall time when the motor-operated valve 5 is in the first-way rotation restricted state Sr (or the rotation restricted state Sc) is shorter than the fall time when the motor-operated valve 5 is in the rotation permitted state Sp. Figure 13 shows the change time rt (rise time) from the start to the end of the rise period and the change time ft (fall time) from the start to the end of the fall period.

[0087] Next, the inventors measured the rise time of the drive current flowing through the coil. Examples of rise times measured over time are shown in Figures 14 and 15. In Figure 14, the motor-operated valve 5 is in the rotation-permitted state Sp before time Tx, and the motor-operated valve 5 is in the first-direction rotation-restricted state Sr after time Tx. In Figure 15, the motor-operated valve 5 is in the rotation-permitted state Sp before time Tx, and the motor-operated valve 5 is in the rotation-restricted state Sc after time Tx. Each black dot corresponds to a rise time.

[0088] As shown in Figures 14 and 15, when the motor-operated valve 5 is in the rotation permitted state Sp, the rise time is long and the difference between the maximum and minimum values ​​is small. When the motor-operated valve 5 is in the first-way rotation restricted state Sr, the rise time is short and the difference between the maximum and minimum values ​​is large. When the motor-operated valve 5 is in the rotation restricted state Sc, the rise time is short and the difference between the maximum and minimum values ​​is very small. In other words, when the motor-operated valve 5 is in the rotation permitted state Sp, the average rise time is large and the variation is small. When the motor-operated valve 5 is in the first-way rotation restricted state Sr, the average rise time is small and the variation is large. When the motor-operated valve 5 is in the rotation restricted state Sc, the average rise time is small and the variation is very small. Therefore, the state of the motor-operated valve 5 can be determined by using at least one of the average rise time and the variation.

[0089] Furthermore, the rise time is long when the motor-operated valve 5 is in the rotation permitted state Sp, and short when the motor-operated valve 5 is in the first-direction rotation restricted state Sr (or rotation constrained state Sc). Therefore, the rise waveform when the motor-operated valve 5 is in the rotation permitted state Sp has a smaller slope than the rise waveform when the motor-operated valve 5 is in the first-direction rotation restricted state Sr (or rotation constrained state Sc). The rise waveform is the waveform of the drive current during the rise period.

[0090] Next, the inventors measured the duty cycle of the drive current flowing through the coil. FIGS. 16 and 17 show examples of the waveform and duty cycle of the drive current during a determination period E, which includes a rise period (change period). "Including the change period" means "including at least a portion of the change period." The determination period E may include a portion of the change period to the extent that the state of the motor-operated valve 5 can be determined. FIG. 16 shows the waveform of the drive current when the motor-operated valve 5 is in the rotation-permitted state Sp, and FIG. 17 shows the waveform of the drive current when the motor-operated valve 5 is in the first-direction rotation-restricted state Sr. During the rise period, the duty cycle is 100%. During the period following the rise period in which the drive current is maintained at the target value (+It), the duty cycle is less than 100%. The number of times the duty cycle reaches 100% in the first-direction rotation-restricted state Sr (or the rotation-restricted state Sc) is less than the number of times the duty cycle reaches 100% in the rotation-permitted state Sp. Therefore, the state of the motor-operated valve 5 can be determined by using the duty cycle in the determination period E, which includes the rise period.

[0091] Next, the inventors observed the waveform of the drive current flowing through the coil. Fig. 18 shows the waveform of the drive current during a determination period E, which includes a rising period (change period). In Fig. 18, the dashed-dotted line shows the waveform of the drive current in the rotation permitted state Sp, and the solid line shows the waveform of the drive current in the first-direction rotation restricted state Sr. The waveform of the drive current in the rotation permitted state Sp differs from the waveform of the drive current in the first-direction rotation restricted state Sr (or the rotation constrained state Sc). Therefore, the state of the motor-operated valve 5 can be determined by using the waveform of the drive current during the determination period E, which includes the rising period.

[0092] The state of the motor-operated valve 5 may be determined using the fall time (fall period) instead of the rise time (rise period). The state of the motor-operated valve 5 can be determined by using at least one of the average value and the amount of variation in the fall time. The state of the motor-operated valve 5 can be determined by using the duty cycle in the determination period E, which includes the fall period. The state of the motor-operated valve 5 can be determined by using the waveform of the drive current in the determination period E, which includes the fall period.

[0093] The motor-operated valve control device 70 has two operating modes: an initialization mode and a normal mode. In the initialization mode, the motor-operated valve control device 70 performs an initialization operation to rotate the rotor 41 in a first direction and position it at a reference position Rx. In the normal mode, the motor-operated valve control device 70 performs an operation based on a control command received from the air conditioner control device 110.

[0094] When power is applied to the motor-operated valve control device 70, the motor-operated valve control device 70 transitions to normal mode and reads out the position of the rotor 41 stored in the nonvolatile memory 75 as the current position of the rotor 41. When the motor-operated valve control device 70 receives a control command including a target valve opening from the air conditioner control device 110, 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 motor-operated valve control device 70 stores the current position in the nonvolatile memory 75 immediately before power is cut off. When the motor-operated 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 out from the nonvolatile memory 75, the motor-operated valve control device 70 transitions to initialization mode and performs an initialization operation. After performing the initialization operation, the motor-operated valve control device 70 transitions to normal mode.

[0095] Next, a first operation example of the motor-operated valve control device 70 will be described with reference to FIG.

[0096] The motor-operated valve control device 70 (computer 80) calculates an average value Ta of a plurality of rise times (S110) when a drive current is supplied to the coil of the stator 60. Specifically, the motor-operated valve control device 70 acquires the rise time of the A-phase current Ia while the rotor 41 is rotating, and calculates an average value Ta of a predetermined number (e.g., 10) of rise times acquired.

[0097] The motor-operated valve control device 70 calculates a difference value Td between the reference value Tr and the average value Ta (S120). The difference value Td is a value obtained by subtracting the average value Ta from the reference value Tr. The reference value Tr is set, for example, based on the average value Ta for the motor-operated valve 5 in the rotation permissive state Sp. A reference value Tr used when the rotor 41 is rotating in the first direction and a reference value Tr used when the rotor 41 is rotating in the second direction may be prepared separately.

[0098] The motor-operated valve control device 70 determines whether the difference value Td is greater than a reference value Th (S130). The reference value Th is set, for example, based on the difference between the average value Ta of the motor-operated valve 5 in the rotation-permitted state Sp and the average value Ta of the motor-operated valve 5 in the first-direction rotation-restricted state Sr (or rotation-constrained state Sc). A reference value Th used when the rotor 41 is rotating in the first direction and a reference value Th used when the rotor 41 is rotating in the second direction may be separately prepared.

[0099] When the difference value Td is equal to or smaller than the determination value Th (N in S130), the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation-permitted state Sp, and returns to calculating the average value Ta (S110).

[0100] When the difference value Td is greater than the determination value Th (Y in S130), the motor-operated valve control device 70 determines whether the motor-operated valve control device 70 is in the initialization mode (S180).

[0101] When the motor-operated valve control device 70 is in the initialization mode (Y in S180), it determines that the motor-operated 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).The motor-operated valve control device 70 then stops the supply of drive current to the coil of the stator 60, stopping the rotation of the rotor 41 (S184).

[0102] When the motor-operated valve control device 70 is not in the initialization mode (N in S180), it determines that the motor-operated valve 5 is in the failure state Sf and notifies the air conditioner control device 110 of the failure of the motor-operated valve 5 (S183).The motor-operated valve control device 70 then stops the supply of drive current to the coil of the stator 60, and stops the rotation of the rotor 41 (S184).When the motor-operated valve control device 70 is not in the initialization mode, the motor-operated valve control device 70 is in the normal mode.

[0103] Next, a second operation example of the motor-operated valve control device 70 will be described with reference to FIG.

[0104] When a drive current is supplied to the coil of the stator 60, the motor-operated valve control device 70 (computer 80) calculates a variation Ba of a plurality of rise times (S210). Specifically, the motor-operated valve control device 70 acquires the rise time of the A-phase current Ia while the rotor 41 is rotating, and calculates a variation Ba of a predetermined number (e.g., 10) of rise times acquired. The variation Ba is the standard deviation of the plurality of rise times. The variation Ba may also be the difference between the maximum and minimum values ​​of the plurality of rise times.

[0105] The motor-operated valve control device 70 determines whether the variation amount Ba is greater than a first determination value Bh1 (S230). The first determination value Bh1 is set, for example, based on the variation amount Ba in the motor-operated valve 5 in the rotation permissive state Sp. Separate first determination values ​​Bh1 may be prepared: one to be used when the rotor 41 is rotating in the first direction, and another to be used when the rotor 41 is rotating in the second direction.

[0106] When the variation amount Ba is equal to or less than the first determination value Bh1 (N in S230), the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation permitted state Sp, and returns to calculating the variation amount Ba (S210).

[0107] When the variation amount Ba is greater than the first determination value Bh1 (Y in S230), the motor-operated valve control device 70 determines whether the motor-operated valve control device 70 is in the initialization mode (S280). The operations of steps S280 to S284 are the same as the operations of steps S180 to S184 in Fig. 19. A description of the operations of steps S280 to S284 will be omitted.

[0108] Next, a third operation example of the motor-operated valve control device 70 will be described with reference to FIG.

[0109] When a drive current is supplied to the coil of the stator 60, the motor-operated valve control device 70 (computer 80) calculates an average value Ta of a plurality of rise times (S310). The motor-operated valve control device 70 calculates a difference value Td between a reference value Tr and the average value Ta (S320). The motor-operated valve control device 70 determines whether the difference value Td is greater than a determination value Th (S330). The operations of steps S310 to S330 are the same as the operations of steps S110 to S130 in FIG. 19 .

[0110] When the difference value Td is equal to or smaller than the determination value Th (N in S330), the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation-permitted state Sp, and returns to calculating the average value Ta (S310).

[0111] When the difference value Td is greater than the judgment value Th (Y in S330), the motor-operated valve control device 70 calculates the amount of variation Ba of the plurality of rise times (S340). The operation of step S340 is the same as the operation of step S210 in Fig. 20. The motor-operated valve control device 70 may calculate the amount of variation Ba of the plurality of rise times that have been newly acquired, or may calculate the amount of variation Ba of the plurality of rise times that was used to calculate the average value Ta.

[0112] The motor-operated valve control device 70 determines whether the variation amount Ba is smaller than a second determination value Bh2 (S350). The second determination value Bh2 is set, for example, based on the variation amount Ba in the motor-operated valve 5 in the rotation-permitted state Sp (or the rotation-constrained state Sc). The second determination value Bh2 used when the rotor 41 is rotating in the first direction and the second determination value Bh2 used when the rotor 41 is rotating in the second direction may be separately prepared.

[0113] When the variation amount Ba is smaller than the second determination value Bh2 (Y in S350), the motor-operated valve control device 70 determines that the motor-operated valve 5 is in a failure state Sf (rotation restriction state Sc), and proceeds to step S383.

[0114] When the variation amount Ba is equal to or greater than the second determination value Bh2 (N in S350), the motor-operated valve control device 70 determines whether the variation amount Ba is greater than a first determination value Bh1 (S360). The first determination value Bh1 is set, for example, based on the variation amount Ba in the motor-operated valve 5 in the rotation permitted state Sp (or the first-direction rotation restricted state Sr). A first determination value Bh1 used when the rotor 41 is rotating in the first direction and a first determination value Bh1 used when the rotor 41 is rotating in the second direction may be separately prepared.

[0115] When the variation amount Ba is equal to or less than the first determination value Bh1 (N in S360), the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation permitted state Sp, and returns to calculating the average value Ta (S310).

[0116] When the variation amount Ba is greater than the first determination value Bh1 (Y in S360), the motor-operated valve control device 70 determines whether the motor-operated valve control device 70 is in the initialization mode (S380). The operations of steps S380 to S384 are the same as the operations of steps S180 to S184 in Fig. 19. A description of the operations of steps S380 to S384 will be omitted.

[0117] Next, a fourth operation example of the motor-operated valve control device 70 will be described with reference to FIG.

[0118] When a drive current is supplied to the coil of the stator 60, the motor-operated valve control device 70 (computer 80) calculates an average value Daa of a plurality of duty cycles (S410). Specifically, when the rotor 41 is rotating, the motor-operated valve control device 70 acquires a plurality of duty cycles of the A-phase current Ia during a determination period E including a rise period, and calculates an average value Da of the plurality of duty cycles. The motor-operated valve control device 70 calculates a predetermined number of average values ​​Da (for example, 10), and then calculates an average value Daa of these average values.

[0119] The motor-operated valve control device 70 determines whether the average value Daa is smaller than a reference value Dh (S430). The reference value Dh is set, for example, based on the average value Daa for the motor-operated valve 5 in the rotation permissive state Sp. The reference value Dh used when the rotor 41 is rotating in the first direction and the reference value Dh used when the rotor 41 is rotating in the second direction may be separately prepared.

[0120] When the average value Daa is equal to or greater than the determination value Dh (N in S430), the motor-operated valve control device 70 determines that the motor-operated valve 5 is in the rotation-permitted state Sp, and returns to calculating the average value Daa (S410).

[0121] When the average value Daa is smaller than the determination value Dh (Y in S430), the motor-operated valve control device 70 determines whether the motor-operated valve control device 70 is in the initialization mode (S480). The operations in steps S480 to S484 are the same as those in steps S180 to S184 in Fig. 19. A description of the operations in steps S480 to S484 will be omitted.

[0122] Next, a fifth operation example of the motor-operated valve control device 70 will be described with reference to FIG.

[0123] First, the dissimilarity index value sv used in the fifth operation example will be described.

[0124] The difference index value sv is a value that indicates the degree of difference between the waveform of the A-phase current Ia and the reference waveform of the A-phase current Ia. The larger the difference index value sv, the greater the degree of difference between the waveform of the A-phase current Ia and the reference waveform of the A-phase current Ia. The motor-operated valve control device 70 calculates the difference index value sv.

[0125] The motor-operated valve control device 70 acquires the waveform of the A-phase current Ia during a determination period E, which includes a rise period, while the rotor 41 is rotating. Specifically, the motor-operated valve control device 70 acquires the A-phase current Ia (current value ia) in time series at a predetermined sampling period.

[0126] The current value ia acquired over time is the waveform of the A-phase current Ia. In this specification, a "waveform" refers to a change over time in a physical quantity (current) 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 data 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 is also included in the "waveform."

[0127] The reference waveform of the A-phase current Ia is set, for example, based on the waveform of the A-phase current Ia in the motor-operated valve 5 in the rotation permitted state Sp. A reference waveform of the A-phase current Ia used when the rotor 41 is rotating in the first direction and a reference waveform of the A-phase current Ia used when the rotor 41 is rotating in the second direction are separately prepared. The reference waveform of the A-phase current Ia is stored in the non-volatile memory 75 during manufacture of the motor-operated valve device 1.

[0128] The reference waveform of the A-phase current Ia is stored as a data table in the non-volatile memory 75. In the data table, times tc at predetermined intervals from the start of the determination period E (time 0) are associated with the reference current value ir at that time tc. The interval between times tc is the same as the sampling period (100 μs). One data table has 40 pairs of times tc and reference current values ​​ir. FIG. 24 shows an example of the data table. In FIG. 24, the unit of time tc is [μs], and the unit of reference current value ir is [mA].

[0129] When the motor-operated valve control device 70 acquires the current value ia at acquisition time t, it reads from the data table the reference current value ir associated with time tc corresponding to the acquisition time t. The motor-operated valve control device 70 calculates a value (difference value dv) by subtracting the reference current value ir from the current value ia. The motor-operated valve control device 70 calculates a value (intermediate value dv2) by squaring the difference value dv. The motor-operated valve control device 70 calculates a difference index value sv by adding together multiple intermediate values ​​dv2 calculated corresponding to one determination period E.

[0130] When the current value ia acquired at acquisition time t between the start (time t1) and end (time t2) of the judgment period E is ia[t], and the reference current value ir associated with time tc corresponding to the acquisition time t in the reference waveform data table is ir[t], the dissimilarity index value sv is expressed by the following equation (1).

[0131]

[0132] The difference index value sv is not limited to one calculated using the above formula (1). The difference index value sv may relate to, for example, the transition of the magnitude of the current value ia at the acquisition time t. Specifically, the motor-operated valve control device 70 calculates a difference value dv between the current value ia acquired at the acquisition time t and a reference current value ir associated with the time tc corresponding to the acquisition 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 during the determination period E that are equal to or greater than a predetermined difference determination value as the difference index value. Such a difference index value also appropriately reflects the degree of difference in the waveform shapes.

[0133] In the fifth operation example, when a drive current is supplied to the coil of the stator 60, the motor-operated valve control device 70 (computer 80) calculates an average value sva of the multiple dissimilarity index values ​​sv (S510). Specifically, when the rotor 41 is rotating, the motor-operated valve control device 70 acquires the waveform of the A-phase current Ia during a determination period E including a rise period, and calculates the dissimilarity index value sv. After calculating a predetermined number (e.g., 10) of dissimilarity index values ​​sv, the motor-operated valve control device 70 calculates an average value sva of these dissimilarity index values ​​sv. The smaller the average value sva, the more similar the waveform of the A-phase current Ia is to the reference waveform of the A-phase current Ia (based on the A-phase current Ia in the rotation permitted state Sp).

[0134] The motor-operated valve control device 70 determines whether the average value sva is greater than a reference value Eh (S530). The reference value Eh is set, for example, based on the average value sva for the motor-operated valve 5 in the rotation permitted state Sp. The reference value Eh is separately prepared 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.

[0135] When the average value sva is equal to or less than the judgment value Eh (N in S530), the motor-operated valve control device 70 judges that the motor-operated valve 5 is in the rotation-permitted state Sp, and returns to calculating the average value sva (S510).

[0136] When the average value sva is greater than the determination value Eh (Y in S530), the motor-operated valve control device 70 determines whether the motor-operated valve control device 70 is in the initialization mode (S580). The operations of steps S580 to S584 are the same as the operations of steps S180 to S184 in Figure 19. A description of the operations of steps S580 to S584 will be omitted.

[0137] The determination value Eh may be set based on the average value sva of the motor-operated valve 5 in the first-direction rotation restricted state Sr. In this configuration, it is determined whether the average value sva is smaller than the determination value Eh (S530), and if the average value sva is equal to or greater than the determination value Eh, the process proceeds to step S510 (N in S530), and if the average value sva is smaller than the determination value Eh, the process proceeds to step S580 (Y in S530).

[0138] In the first to fifth operation examples, the motor-operated valve control device 70 determines the state of the motor-operated valve 5 using the A-phase current Ia in the determination period E that includes the rise period, but may also determine the state of the motor-operated valve 5 using the A-phase current Ia in the determination period E that includes the fall period. In the first to fifth operation examples, the motor-operated valve control device 70 determines the state of the motor-operated valve 5 using the A-phase current Ia, but may also determine the state of the motor-operated valve 5 using the B-phase current Ib, or may also determine the state of the motor-operated valve 5 using the A-phase current Ia and the B-phase current Ib.

[0139] Furthermore, the reference value Tr and the determination value Th (first operation example), the first determination value Bh1 and the second determination value Bh2 (second and third operation examples), the determination value Dh (fourth operation example), and the determination value Eh (fifth operation example) are stored in the non-volatile memory 75 during manufacture of the motor-operated valve device 1. The motor-operated valve control device 70 may set (update) the reference value Tr and the determination value Th, the first determination value Bh1 and the second determination value Bh2, the determination value Dh, and the determination value Eh in response to a command from the air conditioner control device 110, for example. The motor-operated valve control device 70 may also set (update) a reference waveform of the A-phase current Ia (fifth operation example).

[0140] 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 rotor 41, the stator 60 having the A-phase coil 61c and the B-phase coil 62c to which the A-phase current Ia and the B-phase current Ib for rotating the rotor 41 are supplied, 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 computer 80 that determines whether rotation of the rotor 41 is restricted using information related to the rise time period until the A-phase current Ia flowing through the A-phase coil 61c changes from a first current value (-It) to a second current value (+It). As a result, the motor-operated valve control device 70 can determine whether rotation of the rotor 41 is restricted even when the A-phase current Ia and the B-phase current Ib are supplied to the A-phase coil 61c and the B-phase coil 62c.

[0141] Furthermore, the information relating to the rise period is the rise time from the start to the end of the rise period, specifically, the average value Ta of the rise time (first operation example), the amount of variation Ba of the rise time (second operation example), or the average value Ta of the rise time and the amount of variation Ba of the rise time (third operation example). In this way, the motor-operated 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.

[0142] The motor-operated valve 5 also has a stopper mechanism 49 that restricts rotation of the rotor 41 in the first direction when the rotor 41 is in the reference position Rx. When the variation amount Ba is greater than the first determination value Bh1 while the rotor 41 is rotating in the first direction in the initialization mode, the computer 80 determines that rotation of the rotor 41 in the first direction is restricted by the stopper mechanism 49 (first-direction rotation restricted state Sr) (third operation example). This allows the motor-operated valve control device 70 to determine the state of the motor-operated valve 5 in more detail.

[0143] Furthermore, when the variation amount Ba is smaller than a second determination value Bh2 that is smaller than the first determination value Bh1, the motor-operated valve control device 70 determines that the rotation of the rotor 41 in the first direction and the second direction is restricted (rotation restricted state Sc) (third operation example). In this way, the motor-operated valve control device 70 can determine the state of the motor-operated valve 5 in more detail.

[0144] Furthermore, the drive current is controlled by pulse width modulation, and the information relating to the rising period is the duty cycle of the pulse width modulation in the determination period E that includes the rising period (fourth operation example). Even in this manner, the motor-operated valve control device 70 can determine whether or not the rotation of the rotor 41 is restricted, even if the A-phase current Ia and the B-phase current Ib are supplied to the A-phase coil 61c and the B-phase coil 62c.

[0145] Further, the information relating to the rising period is the waveform of the A-phase current Ia flowing through the A-phase coil 61c during the determination period E that includes the rising period (fifth operation example). In this manner, the motor-operated valve control device 70 can determine whether or not the rotation of the rotor 41 is restricted even when the A-phase current Ia and the B-phase current Ib are supplied to the A-phase coil 61c and the B-phase coil 62c.

[0146] 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.

[0147] 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.

[0148] 1...motor-operated valve device, 5...motor-operated valve, 10...valve body, 11...main body member, 13...connecting member, 14...valve chamber, 17...valve port, 18...valve seat, 20...can, 30...valve body, 40...drive mechanism, 41...rotor, 42...valve stem holder, 42c...female thread, 42s...movable stopper, 43...guide bush, 43c...male thread, 44...stopper member, 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...motor-operated valve control device, 75...non-volatile memory, 76...communication device, 77...motor driver, 80...computer

Claims

1. An electric valve control device that controls 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, characterized in having a processing device that determines whether or not rotation of the rotor is restricted using information related to a change period until the drive current flowing through the coil changes from a first current value to a second current value.

2. The motor-operated valve control device according to claim 1, wherein the information relating to the period of change is a change time from the start to the end of the period of change.

3. The motor-operated valve control device according to claim 2, wherein the information relating to the change period is an average value of the change time.

4. The motor-operated valve control device according to claim 2, wherein the information relating to the change period is a variation in the change time.

5. The electric valve control device as described in claim 4, wherein the electric valve has a stopper mechanism that restricts 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 a first judgment value when the rotor is rotating in the first direction.

6. The electric valve control device as described in claim 5, wherein the processing device determines that rotation of the rotor in the first direction and the second direction is restricted when the amount of variation is smaller than a second determination value which is smaller than the first determination value.

7. The motor-operated valve control device according to claim 1, wherein the drive current is controlled by a pulse width modulation method, and the information relating to the change period is a duty cycle of the pulse width modulation method in a determination period that includes the change period.

8. The motor-operated valve control device according to claim 1, wherein the information relating to the change period is a waveform of the drive current flowing through the coil during a determination period that includes the change period.

9. 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 8.

10. A method for determining the state of an electrically-operated 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 method comprising the steps of: determining whether or not rotation of the rotor is restricted using information relating to a period of change until the drive current flowing through the coil changes from a first current value to a second current value.

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