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

Abstract

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 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.SELECTED DRAWING: Figure 8

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes an example of a conventional electric valve. The electric valve includes a valve body, a valve element, a stepping motor, and a stopper mechanism. The stepping motor has a rotor and a stator. When a drive 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 the rotation of the rotor in the first direction when the rotor is in the reference position.

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

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

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The electric valve control device controls the stepping motor in a 1-2 phase excitation mode. In the 1-2 phase excitation mode, there are a two-phase excitation period in which drive currents are supplied to both the A-phase coil and the B-phase coil, and a one-phase excitation period in which 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 obtain only the voltage generated in the coil due to the rotation of the rotor.

[0008] During the one-phase excitation period, when drive current is supplied only to the A-phase coil, the voltage generated in the B-phase coil includes only the voltage component generated by the rotation of the rotor, and when drive current is supplied only to the B-phase coil, the voltage generated in the A-phase coil includes only the voltage component generated by the rotation of the rotor. The electric valve control device can obtain the voltage generated in the one that does not receive the drive current among the A-phase coil and the B-phase coil as the voltage generated by the rotation of the rotor.

[0009] Therefore, when drive current is supplied to only one of the A-phase coil and the B-phase coil, 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.

[0010] However, in the configuration where the electric valve control device controls the stepping motor in a two-phase excitation mode, drive currents are 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 coil due to the rotation of the rotor, and it is difficult to determine whether the 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 the rotation of a rotor is restricted even when a driving current is supplied to a coil of a stator.

Means for Solving the Problems

[0012] The inventors of the present invention used a plurality of electric valves to supply a driving current to the coil of the stator and measured the driving current flowing through the coil, and conducted intensive studies on the measurement results. As a result, the inventors of the present invention found that there is a difference between the waveform of the change period until the driving current in the electric valve in which the rotation of the rotor is restricted changes from the first current value to the second current value and the waveform of the change period in the electric valve in which the rotation of the rotor is not restricted, and thus arrived at the present invention.

[0013] An electric valve control device according to an aspect of the present invention for achieving the above object is an electric valve control device for controlling an electric valve having a valve body having a valve port, a rotor, a stator provided with a coil to which a driving current for rotating the rotor is supplied, and a valve element that moves with respect to the valve port when the rotor rotates, and includes a processing device that determines whether the rotation of the rotor is restricted by using information related to a change period until the driving 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 related to the change period is a change time from the start period to the end period of the change period.

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

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

[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 variation amount is greater than a first determination value while 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 direction and the second direction is restricted when the variation amount is less than a second determination value that is less than the first determination value.

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

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

[0021] To achieve the above object, an electric valve device according to another aspect of the present invention includes the electric valve and the electric valve control device.

[0022] To achieve the above object, a method for determining the state of an electric valve according to another aspect of the present invention is a method for determining the state of an electric valve including a valve body having a valve port, a rotor, a stator provided with a coil to which a drive current for rotating the rotor is supplied, and a valve element that moves relative to the valve port when the rotor rotates. The method is characterized by determining whether the 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.

Advantages of the Invention

[0023] According to the present invention, it is determined whether the rotation of the rotor is restricted by using information related to a change period until a drive current flowing through the coil of the stator changes from a first current value to a second current value. Since it is configured in this way, it is possible to determine whether the rotation of the rotor is restricted even when a drive current is supplied to the coil of the stator.

Brief Description of the Drawings

[0024]

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DETAILED DESCRIPTION OF THE INVENTION

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

[0026] The electric valve device 1 according to the present embodiment is incorporated, for example, in a refrigeration cycle system of an air conditioner and used as a flow control valve for controlling the flow rate of the refrigerant. The electric valve device 1 has an electric valve 5 and an electric valve control device 70. FIG. 1 shows a block diagram of the air conditioner 100 having the electric valve device 1. FIG. 2 shows a cross-sectional view of the electric 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 that are connected in sequence via a pipe 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 communicably connected to the electric valve device 1 (electric valve control device 70). The air conditioner control device 110 controls the flow rate of the refrigerant flowing through the pipe 105 using the electric valve device 1.

[0028] The electric valve 5 has a valve body 10, a can 20, a valve element 30, a drive mechanism 40, and a stator 60.

[0029] The valve body 10 has a body member 11 and a connection member 13. The body member 11 has a cylindrical shape. The 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 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 body member 11 has an annular valve seat 18 that surrounds the valve port 17 in the valve chamber 14. The body member 11 has a circular fitting hole 11a. The fitting hole 11a is disposed on the upper end surface of the body member 11. A through hole 11b communicating with the valve chamber 14 is provided on the bottom surface of the fitting hole 11a. The connection member 13 has an annular plate shape. The inner peripheral edge of the connection member 13 is joined to the upper end of the body member 11. The body member 11 and the connection member 13 are made of a metal such as an 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 peripheral edge of the connection 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 stepped portion 34 which is an upward-facing annular plane. The stepped portion 34 is disposed at the connection portion 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 disposed at 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 contacts the valve seat 18, the valve port 17 closes. When the valve portion 33 separates from the valve seat 18, the valve port 17 opens.

[0032] The drive mechanism 40 moves the valve body 30 in the vertical direction (axis L direction). The opening and closing of the valve port 17 is caused by the movement of the valve body 30. The drive mechanism 40 has a rotor 41, a valve shaft 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 closing spring 47, and a return spring 48.

[0033] FIG. 3 shows a plan view of the rotor 41, the valve shaft holder 42, the stopper member 44, and the stator 60. In FIG. 3, the poles of the rotor 41 and the stator 60 are schematically shown, with the radially outer side of the stator 60 corresponding to the upper side and the radially inner side corresponding 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 cylinder 20. The rotor 41 is disposed inside the cylinder 20. The rotor 41 is rotatable with respect to the valve body 10. The rotor 41 has a plurality of N poles and a plurality of S poles. The plurality of N poles and the plurality of S poles are disposed on the outer peripheral surface of the rotor 41. The plurality of N poles and the plurality of S poles extend in the vertical direction. The plurality of N poles and the plurality of S poles are alternately arranged at equal angular intervals in the circumferential direction. The rotor 41 has, for example, 12 N poles and 12 S poles. The angle between adjacent N poles and S poles is 15 degrees. The position of the rotor 41 has a relationship with the opening degree of the valve port 17.

[0035] The valve shaft holder 42 has a cylindrical shape. The lower end of the valve shaft holder 42 is open. The valve shaft holder 42 has an upper wall portion 42a provided with a shaft hole 42b. The valve shaft 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 peripheral surface of the valve shaft holder 42. The second shaft portion 32 of the valve body 30 is disposed in the shaft hole 42b, and the second shaft portion 32 is movable in the vertical direction in the shaft hole 42b. A closing spring 47 is disposed between a washer 46 disposed on the lower surface of the upper wall portion 42a of the valve shaft holder 42 and a stepped portion 34 of the valve body 30. The closing spring 47 is a coil spring and presses the valve body 30 toward the valve seat 18. A female thread 42c is provided on the inner peripheral surface of the valve shaft 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 screwed into the female thread 42c of the valve shaft holder 42. The first shaft portion 31 of the valve body 30 is disposed inside the guide bush 43. The guide bush 43 supports the valve body 30 so as to be movable 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 peripheral surface of the stopper member 44. The fixed stopper 44s is fixed to the valve body 10.

[0038] 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 element 30 is disposed inside the fixing portion 45a. The fixing portion 45a is joined to the second shaft portion 32. The flange portion 45b is connected to the lower end of the fixing portion 45a. A return spring 48 is disposed outside the retaining member 45. The return spring 48 is a coil spring.

[0039] The electric valve 5 has a drive mechanism 40 that is used without decelerating the rotation of the rotor 41. The electric valve 5 may have a drive mechanism having a speed reduction mechanism that decelerates the rotation of the rotor 41 instead of the drive mechanism 40.

[0040] The stator 60 has a cylindrical shape. The stator 60 has 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 periphery. The tip of the pole tooth 61a faces downward, and the tip of the pole tooth 61b faces upward. The pole teeth 61a and 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 two adjacent pole teeth 61a and 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 with different polarities from each other.

[0042] The B-phase stack 62 has a plurality of claw-pole type pole teeth 62a and 62b on its inner circumference. The tip of the pole tooth 62a faces downward, and the tip of the pole tooth 62b faces 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 with different polarities from each other. The B-phase stack 62 has the same configuration as the A-phase stack 61.

[0043] The A-phase stack 61 is coaxially arranged above the B-phase stack 62. The B-phase stack 62 is 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 61a and 62a are aligned in the direction of the axis L.

[0044] Inside the stator 60, the can 20 is arranged. Inside the can 20, the rotor 41 is arranged. The stator 60 and the rotor 41 form a stepping motor 66. The stepping motor 66 is connected to the electric valve control device 70.

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

[0046] When the pulse P is 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 the first direction (clockwise in FIG. 3). When the pulse P is 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 the second direction (counterclockwise in FIG. 3).

[0047] 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 the 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 easily understand 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 attached to the reference pole teeth 61a and the reference magnetic pole (S pole) of the rotor 41.

[0048] When the pulse P is 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 due to 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 and the valve portion 33 contacts the valve seat 18. The position of the rotor 41 at this time is the valve closing 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 contacts 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 are 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.

[0049] When a pulse P is 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 move upward due to 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. Together with the retaining member 45, the valve body 30 moves upward, and the valve body 30 separates from the valve seat 18. The position of the rotor 41 when the fluid flow rate (the opening degree of the valve port 17) at the valve port 17 in a predetermined flow rate measurement environment is a predetermined set value is defined as the valve opening position Ro. The set value is appropriately set according to the configuration and application of the electric valve device 1, etc. 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.

[0050] 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 number of strokes Ns. That is, when the number of pulses P of the number of strokes Ns is input to the stepping motor 66 of the electric valve 5 where the rotor 41 is at the fully open position Rz, the rotor 41 is positioned at the reference position Rx. For example, the number of strokes Ns is 500.

[0051] In the electric valve 5, the central axes of the valve port 17, the valve seat 18, the cam 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.

[0052] The electric 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 electric valve control device 70 has a non-volatile memory 75, a communication device 76, a motor driver 77, and a computer 80. The electric valve control device 70 controls the electric valve 5 based on an instruction from the air conditioner control device 110.

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

[0054] The communication device 76 is communicably connected to the air conditioner control device 110 via the wired communication bus 120. The air conditioner 100 adopts a communication method such as, for example, Local Interconnect Network (LIN) or Controller Area Network (CAN). Note that the communication device 76 may be wirelessly communicably connected to the air conditioner control device 110.

[0055] FIG. 8 is a diagram schematically showing a computer 80, a motor driver 77, and a stepping motor 66 included in the motor 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.

[0056] The motor driver 77 is controlled by the computer 80. The motor driver 77 supplies a drive current for rotating the rotor 41 to the stator 60. The motor driver 77 supplies an A-phase current Ia to the A-phase coil 61c and a B-phase current Ib to the B-phase coil 62c.

[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 the step signal is input while the direction signal corresponding to the first direction (for example, an H-level signal) is input to the motor driver 77, it corresponds to the pulse P being input to the stepping motor 66 in ascending order. When the step signal is input while the direction signal corresponding to the second direction (for example, an L-level signal) is input to the motor driver 77, it corresponds to the pulse P being input to the stepping motor 66 in descending order. FIG. 9 schematically shows an example of the relationship between the pulse P input to the stepping motor 66 and the step signal and the direction signal input to the motor driver 77.

[0058] Also, the motor driver 77 receives a current control signal (CONTROL) from the computer 80. The current control signal is a signal for setting the target values of the phase A current Ia and the phase B current Ib (the phase A current target value and the phase B current target value) in the motor driver 77.

[0059] FIG. 10 shows an example of the correspondence relationship between the pulse P and the phase A current target value and the phase B current target value. For the pulse P[1], “+It” is set as the phase A current target value, and “-It” is set as the phase B current target value. For the pulse P[2], “+It” is set as the phase A current target value, and “+It” is set as the phase B current target value. For the pulse P[3], “-It” is set as the phase A current target value, and “+It” is set as the phase B current target value. For the pulse P[4], “-It” is set as the phase A current target value, and “-It” is set as the phase B 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] Fig. 11 schematically shows an example of the waveforms of the phase A current Ia and the phase B current Ib when a pulse P is input to the stepping motor 66 in ascending order.

[0061] In Figs. 10 and 11, the signs (+ / -) indicate the direction in which the current flows. "+" 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 the 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 the full-step method. The step angle of the stepping motor 66 is 7.5 degrees. Note that the stepping motor 66 may be controlled in the half-step method or the micro-step method.

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

[0064] The H-bridge circuit 77A is connected to the phase A coil 61c. The H-bridge circuit 77A has switches SW11, SW12, SW13, and SW14. The upstream end of the H-bridge circuit 77A is connected to the power supply, and the downstream end of the H-bridge circuit 77A is connected to the reference potential of the substrate 71 via a shunt resistor 78A. The H-bridge circuit 77B is connected to the phase B coil 62c. The H-bridge circuit 77B has switches SW21, SW22, SW23, and SW24. The upstream end of the H-bridge circuit 77B is connected to the power supply, and the downstream end of the H-bridge circuit 77B is connected to the reference potential of the substrate 71 via a shunt resistor 78B. The switches SW11, SW12, SW13, SW14 and the switches SW21, SW22, SW23, SW24 are, for example, N-channel MOSFETs or P-channel MOSFETs, and both may be mixed.

[0065] The switches SW11, SW12, SW13, SW14 and the switches SW21, SW22, SW23, SW24 are controlled to be on (conducting state) / off (non-conducting state).

[0066] The current control unit 77C controls the H-bridge circuits 77A, 77B in a pulse width modulation method (PWM method) according to the step signal and the direction signal from the computer 80. In this embodiment, the PWM frequency is 20 kHz.

[0067] When supplying the A-phase current Ia flowing from the terminal A1 to the 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 becomes the same as the magnitude of the A-phase current target value.

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

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

[0070] When supplying the B-phase current Ib flowing from the terminal B2 to the 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-times of the switches SW22 and SW23 so that the magnitude of the B-phase current Ib becomes 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 a pulse width modulation method. Each switch is turned on / 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 become their respective target values.

[0072] The computer 80 is a microcomputer for embedded devices in which a CPU, a ROM, a RAM, an analog-to-digital converter (ADC), etc. are incorporated in 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 a step signal and a direction signal from the output ports OP1 and OP2. The computer 80 has a communication port COM. The communication port COM 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) acquires 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 a pulse P to the stepping motor 66 to rotate the rotor 41 in the first direction or the second direction. Specifically, the rotation control unit 81 controls the motor driver 77 based on an instruction from the air conditioner control device 110, supplies a phase A current Ia to the phase A coil 61c, and supplies a phase B current Ib to the phase B 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 related to a change period until the phase A current Ia flowing through the phase A coil 61c changes from the first current value to the second current value. The acquisition unit 82 may acquire information related to a change period until the phase B current Ib flowing through the phase B coil 62c changes from the first current value to the second current value. Examples of information related to the change period are shown below.

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

[0079] When the first current value is "+It" and the second current value is "-It": (6) The change time (fall time) from the start period to the end period of the change period (fall period) (7) The average value of a plurality of fall times (8) The variation amount of a plurality of fall times (9) Duty cycle during determination period E including the fall period (10) Difference between the waveform of phase A current Ia and the reference waveform of phase A current Ia during determination period E including the fall period

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

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

[0082] The rotation allowable state Sp is a state in which rotation of the rotor 41 in the first direction and the second direction is allowed.

[0083] The first direction rotation restriction 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 restriction state Sr, the rotor 41 is at the reference position Rx. In the first direction rotation restriction state Sr, rotation of the rotor 41 in the second direction is not restricted.

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

[0085] The inventors of the present invention 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 is in the rotation-permitted state Sp and the waveform of the drive current measured when the motor-operated valve 5 is in the first-direction rotation-restricted state Sr are superimposed. In FIG. 12, time advances from left to right.

[0086] As shown in FIG. 12, the waveform of the drive current when the motor-operated valve 5 is in the first-direction 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 restraint 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. That is, the rise time when the motor-operated valve 5 is in the first-direction rotation-restricted state Sr (or rotation restraint 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-direction rotation-restricted state Sr (or rotation restraint state Sc) is shorter than the fall time when the motor-operated valve 5 is in the rotation-permitted state Sp. FIG. 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. FIGS. 14 and 15 show examples of the rise time measured in chronological order. In FIG. 14, before time Tx, the motor valve 5 is in the rotation-permitted state Sp, and after time Tx, the motor valve 5 is in the first-direction rotation-restricted state Sr. In FIG. 15, before time Tx, the motor valve 5 is in the rotation-permitted state Sp, and after time Tx, the motor valve 5 is in the rotation-restrained state Sc. Each black dot corresponds to the rise time.

[0088] As shown in FIGS. 14 and 15, when the motor valve 5 is in the rotation-permitted state Sp, the rise time is long and the difference between the maximum value and the minimum value is small. When the motor valve 5 is in the first-direction rotation-restricted state Sr, the rise time is short and the difference between the maximum value and the minimum value is large. When the motor valve 5 is in the rotation-restrained state Sc, the rise time is short and the difference between the maximum value and the minimum value is very small. That is, when the motor valve 5 is in the rotation-permitted state Sp, the average value of the rise time is large and the variation amount is small. When the motor valve 5 is in the first-direction rotation-restricted state Sr, the average value of the rise time is small and the variation amount is large. When the motor valve 5 is in the rotation-restrained state Sc, the average value of the rise time is small and the variation amount is very small. Therefore, the state of the motor valve 5 can be determined by using at least one of the average value and the variation amount of the rise time.

[0089] Also, when the motor valve 5 is in the rotation-permitted state Sp, the rise time is long, and when the motor valve 5 is in the first-direction rotation-restricted state Sr (or the rotation-restrained state Sc), the rise time is short. Therefore, the rise waveform when the motor valve 5 is in the rotation-permitted state Sp has a smaller slope than the rise waveform when the motor valve 5 is in the first-direction rotation-restricted state Sr (or the rotation-restrained 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 of the drive current and the duty cycle in the determination period E including the rising period (changing period). "Including the changing period" means "including at least a part of the changing period". The determination period E only needs to include a part of the changing period to such an extent that the state of the motorized valve 5 can be determined. FIG. 16 shows the waveform of the drive current when the motorized valve 5 is in the rotation-permitted state Sp, and FIG. 17 shows the waveform of the drive current when the motorized valve 5 is in the first-direction rotation-restricted state Sr. In the rising period, the duty cycle becomes 100%. In the period during which the drive current is maintained at the target value (+It) following the rising period, the duty cycle becomes smaller than 100%. The number of times the duty cycle becomes 100% in the first-direction rotation-restricted state Sr (or the rotation-restrained state Sc) is less than the number of times the duty cycle becomes 100% in the rotation-permitted state Sp. Therefore, the state of the motorized valve 5 can be determined by using the duty cycle in the determination period E including the rising 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 in the determination period E including the rising period (changing 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 is different from the waveform of the drive current in the first-direction rotation-restricted state Sr (or the rotation-restrained state Sc). Therefore, the state of the motorized valve 5 can be determined by using the waveform of the drive current in the determination period E including the rising period.

[0092] Note that, for the determination of the state of the electric valve 5, the fall time (fall period) may be used instead of the rise time (rise period). By using at least one of the average value and the variation amount of the fall time, the state of the electric valve 5 can be determined. By using the duty cycle in the determination period E including the fall period, the state of the electric valve 5 can be determined. By using the waveform of the drive current in the determination period E including the fall period, the state of the electric valve 5 can be determined.

[0093] The electric valve control device 70 has, as operation modes, an initialization mode and a normal mode. In the initialization mode, the electric valve control device 70 executes an initialization operation of rotating the rotor 41 in the first direction to position it at the reference position Rx. In the normal mode, the electric valve control device 70 executes an operation based on a control command (excluding the initialization command) received from the air conditioner control device 110.

[0094] When the power is turned on, the electric valve control device 70 shifts to the 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 including the target valve opening degree from the air conditioner control device 110, it rotates the rotor 41 from the current position to the position corresponding to the target valve opening degree and sets the position as the new current position. The electric valve control device 70 stores the current position in the non-volatile memory 75 immediately before the power is turned 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 shifts to the initialization mode and executes the initialization operation. After executing the initialization operation, the electric valve control device 70 shifts to the normal mode.

[0095] Next, a first operation example of the electric valve control device 70 will be described with reference to FIG. 19.

[0096] When a drive current is supplied to the coil of the stator 60, the electric valve control device 70 (computer 80) calculates the average value Ta of a plurality of rise times (S110). Specifically, when the rotor 41 is rotating, the electric valve control device 70 acquires the rise time of the A-phase current Ia, and when a predetermined number (for example, 10) of rise times are acquired, it calculates their average value Ta.

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

[0098] The electric valve control device 70 determines whether the difference value Td is greater than the determination value Th (S130). The determination value Th is set based on, for example, the difference value between the average value Ta in the electric valve 5 in the rotation allowable state Sp and the average value Ta in the electric valve 5 in the first direction rotation restriction state Sr (or rotation restraint state Sc). The determination value Th used when the rotor 41 is rotating in the first direction and the determination value Th used when the rotor 41 is rotating in the second direction may be prepared separately.

[0099] When the difference value Td is less than or equal to the determination value Th (N in S130), the electric valve control device 70 determines that the electric valve 5 is in the rotation allowable state Sp and returns to the calculation of the average value Ta (S110).

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

[0101] When the electric valve control device 70 is in the initialization mode (Y in S180), it determines that the electric valve 5 is in the first-direction rotation restriction 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 has been completed (S182). Then, the electric valve control device 70 stops supplying the drive current to the coil of the stator 60 and stops the rotation of the rotor 41 (S184).

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

[0103] Next, a second operation example of the electric valve control device 70 will be described with reference to FIG. 20.

[0104] When a drive current is supplied to the coil of the stator 60, the electric valve control device 70 (computer 80) calculates the variation amount Ba of a plurality of rise times (S210). Specifically, when the rotor 41 is rotating, the electric valve control device 70 acquires the rise time of the A-phase current Ia, and when a predetermined number (for example, 10) of rise times are acquired, it calculates the variation amount Ba thereof. The variation amount Ba is the standard deviation of a plurality of rise times. The variation amount Ba may be the difference value between the maximum value and the minimum value of a plurality of rise times.

[0105] The electric valve control device 70 determines whether the variation amount Ba is greater than the first determination value Bh1 (S230). The first determination value Bh1 is set based on, for example, the variation amount Ba of the electric valve 5 in the rotation allowable state Sp. The first determination value Bh1 used when the rotor 41 is rotating in the first direction and the first determination value Bh1 used when the rotor 41 is rotating in the second direction may be prepared separately.

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

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

[0108] Next, a third operation example of the electric valve control device 70 will be described with reference to FIG. 21.

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

[0110] When the difference value Td is equal to or less than the determination value Th (N in S330), the electric valve control device 70 determines that the electric valve 5 is in the rotation allowable state Sp, and returns to the calculation of the average value Ta (S310).

[0111] When the difference value Td is greater than the determination value Th (Y in S330), the electric valve control device 70 calculates the variation amount Ba of a plurality of rise times (S340). The operation in step S340 is the same as the operation in step S210 in FIG. 20. The electric valve control device 70 may calculate the variation amount Ba of the newly acquired plurality of rise times, or may calculate the variation amount Ba of the plurality of rise times used for the calculation of the average value Ta.

[0112] The electric valve control device 70 determines whether the variation amount Ba is greater than the second determination value Bh2 (S350). The second determination value Bh2 is set based on, for example, the variation amount Ba in the electric valve 5 in the rotation allowable state Sp (or the rotation restraint 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 prepared separately.

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

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

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

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

[0117] Next, a fourth operation example of the electric valve control device 70 will be described with reference to FIG. 22.

[0118] When a drive current is supplied to the coil of the stator 60, the electric valve control device 70 (computer 80) calculates the average value Daa of a plurality of duty cycles (S410). Specifically, when the rotor 41 is rotating, the electric valve control device 70 acquires a plurality of duty cycles of the A-phase current Ia in the determination period E including the rising period, and calculates the average value Da of the plurality of duty cycles. When the electric valve control device 70 calculates a predetermined number (for example, 10) of average values Da, it calculates their average value Daa.

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

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

[0121] When the average value Daa is smaller than the determination value Dh (Y in S430), the electric valve control device 70 determines whether it is in the initialization mode (S480). The operations in steps S480 to S484 are the same as the operations in steps S180 to S184 in FIG. 19. The description of the operations in steps S480 to S484 is omitted.

[0122] Next, a fifth operation example of the electric valve control device 70 will be described with reference to FIG. 23.

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

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

[0125] When the rotor 41 is rotating, the motor valve control device 70 acquires the waveform of the phase A current Ia during the determination period E including the rising period. Specifically, the motor valve control device 70 acquires the phase A current Ia (current value ia) in time series at a predetermined sampling period.

[0126] The current value ia acquired in time series is the waveform of the phase A current Ia. In this specification, the "waveform" is the time change of a physical quantity (current) at a fixed point. When visualizing the "waveform", it is expressed on a coordinate plane with the physical quantity on the vertical axis and time on the horizontal axis. Also, invisible things such as a data table in which physical quantity data and time data are associated and stored in the RAM or non-volatile memory 75 of the computer 80 are also included in the "waveform".

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

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

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

[0130] When the current value ia acquired at the acquisition time t from the start time (time t1) to the end time (time t2) of the determination period E is denoted as ia[t], and the reference current value ir associated with the time tc corresponding to the acquisition time t in the data table of the reference waveform is denoted as ir[t], the difference degree index value sv is represented by the following formula (1).

[0131]

Equation

[0132] Note that the difference index value sv is not limited to being calculated using the above formula (1). The difference index value sv may be related to, for example, the change in the magnitude of the current value ia at the acquisition time t. Specifically, the motor 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 valve control device 70 uses the number of difference values dv that are greater than or equal to a predetermined difference determination value among the plurality of difference values dv calculated during the determination period E as the difference index value. Such a difference index value also appropriately reflects the degree of difference in the shape of the waveform.

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

[0134] The motor valve control device 70 determines whether the average value sva is greater than the determination value Eh (S530). The determination value Eh is set based on, for example, the average value sva of the motor valve 5 in the rotation allowable state Sp. Separate determination values Eh are prepared for when the rotor 41 is rotating in the first direction and when the rotor 41 is rotating in the second direction.

[0135] When the average value sva is less than or equal to the determination value Eh (N in S530), the motor valve control device 70 determines that the motor valve 5 is in the rotation allowable state Sp, and returns to the calculation of the average value sva (S510).

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

[0137] Note that the determination value Eh may be set based on the average value sva in the electric valve 5 in the first-direction rotation restriction state Sr. In this configuration, it is determined whether the average value sva is less than the determination value Eh (S530). When the average value sva is equal to or greater than the determination value Eh, the process proceeds to step S510 (N in S530). When the average value sva is less than the determination value Eh, the process proceeds to step S580 (Y in S530).

[0138] In the first to fifth operation examples, the electric valve control device 70 determines the state of the electric valve 5 using the A-phase current Ia in the determination period E including the rising period. However, the state of the electric valve 5 may be determined using the A-phase current Ia in the determination period E including the falling period. In the first to fifth operation examples, the electric valve control device 70 determines the state of the electric valve 5 using the A-phase current Ia. However, the state of the electric valve 5 may be determined using the B-phase current Ib, or the state of the electric valve 5 may be determined using both the A-phase current Ia and the B-phase current Ib.

[0139] Also, 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 at the time of manufacturing the electric valve device 1. The electric 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, for example, the air conditioner control device 110. Also, the electric valve control device 70 may set (update) the reference waveform (fifth operation example) of the A-phase current Ia.

[0140] 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 provided with an A-phase coil 61c and a B-phase coil 62c to which an A-phase current Ia and a B-phase current Ib for rotating the rotor 41 are supplied, and a valve element 30 that moves with respect 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 by using information related to a rising 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). Because of this, the electric 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.

[0141] Also, the information related to the rising period is the rising time from the start period to the end period of the rising period. Specifically, it is the average value Ta of the rising time (first operation example), the variation amount Ba of the rising time (second operation example), or the average value Ta of the rising time and the variation amount Ba of the rising time (third operation example). By doing so, 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.

[0142] Also, the electric valve 5 has a stopper mechanism 49 that restricts the rotation of the rotor 41 in a first direction when the rotor 41 is at the reference position Rx. Then, 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 the rotation of the rotor 41 in the first direction is restricted by the stopper mechanism 49 (first direction rotation restriction state Sr) (third operation example). By doing so, the electric valve control device 70 can determine the state of the electric valve 5 in more detail.

[0143] Further, when the variation amount Ba is smaller than the second determination value Bh2 which is smaller than the first determination value Bh1, the electric valve control device 70 determines that the rotation of the rotor 41 in the first direction and the second direction is restricted (rotation restraint state Sc) (third operation example). By doing so, the electric valve control device 70 can more finely determine the state of the electric valve 5.

[0144] Also, the drive current is controlled by a pulse width modulation method. And the information related to the rising period is the duty cycle of the pulse width modulation method in the determination period E including the rising period (fourth operation example). Even in this case, the electric 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.

[0145] Also, the information related to the rising period is the waveform of the A-phase current Ia flowing through the A-phase coil 61c in the determination period E including the rising period (fifth operation example). Even in this case, the electric 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, each term indicating a shape such as "cylinder" or "cylindrical column" is also used for a member or a part of a member that substantially has the shape of the term. For example, a "cylindrical member" includes a cylindrical member and a member that is substantially cylindrical. Also, in this specification, the term "the same" may include cases where they are exactly the same and cases where they are substantially the same.

[0147] Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments. For those skilled in the art, those obtained by appropriately adding, deleting, or changing the design of components, or those obtained by appropriately combining the features of the embodiments, are included in the scope of the present invention as long as they do not depart from the spirit of the present invention.

Explanation of Reference Numerals

[0148] 1… Electric valve device, 5… Electric valve, 10… Valve body, 11… Body member, 11a… Fitting hole, 11b… Through hole, 13… Connecting member, 14… Valve chamber, 15… First conduit, 16… Second conduit, 17… Valve port, 18… Valve seat, 20… Cam, 30… Valve body, 31… First shaft portion, 32… Second shaft portion, 33… Valve portion, 34… Step portion, 40… Driving mechanism, 41… Rotor, 41a… Fitting hole, 42… Valve shaft holder, 42a… Upper wall portion, 42b… Shaft hole, 42c… Female thread, 42s… Movable stopper, 43… Guide bush, 43a… Base portion, 43b… Support portion, 43c… Male thread, 44… Stopper member, 44s… Fixed stopper, 45… Anti-disengagement member, 45a… Fixed portion, 45b… Flange portion, 46… Washer, 47… Closing spring, 48… Return spring, 49… Stopper mechanism, 60… Stator, 61… Phase A stack, 61a… Pole tooth, 61b… Pole tooth, 61c… Phase A coil, 62… Phase B stack, 62a… Pole tooth, 62b… Pole tooth, 62c… Phase B coil, 66… Stepping motor, 70… Electric valve control device, 71… Substrate, 75… Non-volatile memory, 76… Communication device, 77… Motor driver, 77A… H-bridge circuit, 77B… H-bridge circuit, 77C… Current control unit, 78A… Shunt resistor, 78B… Shunt resistor, 80… Computer, 81… Rotation control unit, 82… Acquisition unit, 83… Judgment unit, 100… Air conditioner, 101… Compressor, 102… Condenser, 103… Evaporator, 105… Pipe, 110… Air conditioner control device, 120… Wired communication bus, L… Axis

Claims

1. An electric valve control device for controlling an electric valve having a valve body with a valve port, a rotor, a stator provided with a coil to which a drive current for rotating the rotor is supplied, and a valve element that moves with respect to the valve port when the rotor rotates, comprising: A processing device that determines whether the 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. The electric valve control device is characterized by this.

2. The electric valve control device according to claim 1, wherein the information related to the change period is a change time from the start period to the end period of the change period.

3. The electric valve control device according to claim 2, wherein the information related to the change period is an average value of the change time.

4. The electric valve control device according to claim 2, wherein the information related to the change period is an amount of variation of the change time.

5. The electric valve has a stopper mechanism that restricts the rotation of the rotor in a first direction when the rotor is at a reference position, 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 determination value while the rotor is rotating in the first direction. The electric valve control device according to claim 4.

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

7. The drive current is controlled by a pulse width modulation method, The electric valve control device according to claim 1, wherein the information related to the change period is a duty cycle of the pulse width modulation method in a determination period including the change period.

8. The electric valve control device according to claim 1, wherein the information related to the change period is a waveform of the drive current flowing through the coil in a determination period including the change period.

9. An electric valve device comprising the electric valve and the electric valve control device according to any one of claims 1 to 8.

10. A method for determining the state of an electric valve, comprising a valve body having a valve port, a rotor, a stator provided with a coil to which a drive current for rotating the rotor is supplied, and a valve element that moves relative to the valve port when the rotor rotates, wherein: 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 is used to determine whether the rotation of the rotor is restricted. A method for determining the state of an electric valve, characterized by this.

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