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

Abstract

To provide an electric valve control device capable of suppressing noise by shortening the time taken for an initialization operation of an electric valve, and to provide an electric valve device having the electric valve control device, and a control method of the electric valve.SOLUTION: An electric valve 5 includes a stepping motor 66 having a rotor 41 and a stator 60. The stator 60 is connected to a current circuit having a switch element. An electric valve control device 70 acquires an OFF time of the switch element when driving current for rotating the rotor 41 in a first direction is supplied to the stator 60. The electric valve control device 70 determines whether the electric valve 5 is in a first rotation regulated state in which rotation in the first direction of the rotor 41 is regulated on the basis of the OFF time.SELECTED DRAWING: Figure 2

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 controlling an electric valve.

Background Art

[0002] Patent Document 1 discloses an example of a conventional electric valve. Such an electric valve is incorporated in a refrigeration cycle of an air conditioner. The electric valve has a valve body, a valve element, and a stepping motor for moving the valve element. The stepping motor has a rotor and a stator. When a pulse is input to the stepping motor, the rotor rotates. The valve element moves according to the rotation of the rotor. When the rotor is in the reference position, a movable stopper that rotates with the rotor abuts against a fixed stopper fixed to the valve body, and the rotation of the rotor in the first direction is restricted.

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

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The electric valve control device inputs pulses to the stepping motor until the number of pulses input to the stepping motor reaches the initialization number. Therefore, the electric valve control device may input pulses even after the rotor is positioned at the reference position, and the initialization operation takes a long time. Further, when a pulse is input to the stepping motor after the rotor is positioned at the reference position, the movable stopper repeatedly collides with the fixed stopper and noise is generated. In particular, when the position of the rotor immediately before the initialization operation is close to the reference position, the noise is generated for a long time.

[0006] Therefore, an object of the present invention is to provide an electric valve control device and an electric valve device having the electric valve control device that can shorten the time required for the initialization operation of the electric valve and suppress noise, and a control method for the electric valve.

Means for Solving the Problems

[0007] When a pulse is input to the stepping motor, the rotor rotates. Specifically, when a drive current corresponding to the pulse is supplied to the coil of the stator of the stepping motor, the rotor rotates. When the rotor rotates, the magnetic flux passing through the coil changes, and a voltage is generated in the coil. This voltage is called back electromotive force (BEMF).

[0008] The stator is connected to a current circuit that supplies a drive current. The current circuit has a switching element. The current circuit has a target value of the drive current and a lower limit value of the drive current that is smaller than the target value by a fixed value. The current circuit operates in a method (hereinafter referred to as "fixed ripple current control method") in which the switching element is turned on (conducting state) when the drive current is smaller than the lower limit value and the switching element is turned off (non-conducting state) when the drive current reaches the target value. The off time of the switching element is referred to as Toff and is represented by the following formula (1).

[0009]

Equation

[0010] I is the current flowing through the coil, R is the resistance of the coil, L is the inductance of the coil, and ΔI is the fixed value. Toff is related to the BEMF.

[0011] The inventors of the present invention have found that in an electric valve, the rotation state of the rotor is different before and after the rotation of the rotor in the first direction is restricted, and the BEMF and Toff are also different, and thus the present invention has been achieved.

[0012] In order to achieve the above object, an electric valve control device according to an aspect of the present invention is a valve body having a valve port, a stepping motor having a rotor and a stator, a valve body facing the valve port and moving toward the valve port when the rotor rotates in a first direction, and a stopper mechanism for restricting the rotation of the rotor in the first direction when the rotor is in a reference position, an electric valve control device for controlling an electric valve, comprising the stator is connected to a current circuit that supplies a drive current, the current circuit has a switch element, and the switch element is turned on when the drive current is smaller than a lower limit value that is smaller than a target value by a fixed value, and the switch element is turned off when the drive current reaches the target value, and operates in a manner the electric valve control device an off-time acquisition unit that acquires an off time of the switch element when the drive current for rotating the rotor in the first direction is supplied to the stator, and a state determination unit that determines whether the electric valve is in a first rotation restriction state in which the rotation of the rotor in the first direction is restricted, based on the off time. It is characterized by having

[0013] In the present invention, it is preferable that the state determination unit determines whether the electric valve is in the first rotation restriction state based on the degree of difference between the waveform of the reciprocal of the off time acquired by the off-time acquisition unit and a reference waveform of the reciprocal of the off time.

[0014] In the present invention, the reference waveform is set based on a waveform of the reciprocal of the off-time obtained when the drive current for rotating the rotor in the first direction is supplied to the stator, the state determination unit calculates a difference index value indicating the degree of difference between the waveform of the reciprocal of the off-time acquired by the off-time acquisition unit and the reference waveform, and determines whether or not the electric valve is in the first rotation restriction state based on a comparison result between the difference index value and a difference determination value, which is preferable.

[0015] In the present invention, the reference waveform is a data table in which time and a reference value of the reciprocal of the off-time at that time are associated, the state determination unit calculates an intermediate value that is a value obtained by squaring a difference value between the reciprocal of the off-time acquired by the off-time acquisition unit at the acquisition time corresponding to the time and the reference value associated with the time, it is preferable that the state determination unit calculates the difference index value by adding up a plurality of the intermediate values.

[0016] In the present invention, the electric valve control device further includes a rotation control unit that inputs a pulse to the stepping motor to rotate the rotor, and a reference waveform setting unit that sets the reference waveform, the current circuit supplies the drive current corresponding to the pulse to the stator in response to the input of the pulse to the stepping motor, the rotation control unit performs a preparation operation of inputting a preparation number of pulses to the stepping motor to rotate the rotor in the second direction, and following the preparation operation, performs a warm-up operation of inputting a warm-up number of pulses equal to or less than the preparation number to the stepping motor to rotate the rotor in the first direction, it is preferable that the reference waveform setting unit sets the waveform of the reciprocal of the off-time acquired by the off-time acquisition unit during the warm-up operation as the reference waveform.

[0017] 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.

[0018] To achieve the above object, a control method for an electric valve according to another aspect of the present invention is a control method for an electric valve having a valve body having a valve port, a stepping motor having a rotor and a stator, a valve body facing the valve port and moving toward the valve port when the rotor rotates in a first direction, and a stopper mechanism that restricts rotation of the rotor in the first direction when the rotor is in a reference position, the method comprising: the stator is connected to a current circuit that supplies a drive current, the current circuit has a switching element, and operates in such a manner that the switching element is turned on when the drive current is less than a lower limit value that is a fixed value smaller than a target value, and the switching element is turned off when the drive current reaches the target value, the control method includes an off-time acquisition step of acquiring an off time of the switching element of the current circuit when the drive current for rotating the rotor in the first direction is supplied to the stator, and a state determination step of determining, based on the off time, whether or not the electric valve is in a first rotation restriction state in which rotation of the rotor in the first direction is restricted.

Advantages of the Invention

[0019] According to one aspect of the present invention, the electric valve control device acquires the off time of the switching element of the current circuit when the drive current for rotating the rotor in the first direction is supplied to the stator, and determines, based on the off time, whether or not the electric valve is in a first rotation restriction state in which rotation of the rotor in the first direction is restricted.

[0020] As a result of this, for an electric valve that can operate normally, when the electric valve control device determines that the electric valve is in the first rotation restriction state, the rotor is at the reference position. Therefore, when the electric valve control device determines that the electric valve is in the first rotation restriction state, by stopping the rotation of the rotor in the first direction, the time required for the initialization operation can be shortened. In addition, after the rotor is positioned at the reference position, it is possible to suppress the occurrence of noise for a long time.

[0021] In addition, the electric valve control device determines whether the electric valve is in the first rotation restriction state based on the off-time of the switch element in the current circuit. Therefore, components for determining the state of the electric valve based on the rotation of the rotor such as a rotation angle sensor are unnecessary, and the electric valve and the electric valve control device can have a simple configuration.

[0022] Also, for example, when determining the state of the electric valve based on the back electromotive force, since the back electromotive force is obtained when no drive current flows through the coil of the stator, the timing for obtaining the back electromotive force is limited. On the other hand, when determining the state of the electric valve based on the off-time, the off-time can be obtained even when a drive current flows through the coil of the stator. Therefore, the electric valve control device can determine in a timely manner whether the electric valve is in the first rotation restriction state.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

Figure 30

Figure 31

Figure 32

Mode for Carrying Out the Invention

[0024] Hereinafter, the motor-operated valve device will be described with reference to FIGS. 1 to 32.

[0025] FIG. 1 is a block diagram of an air conditioner system having an electric valve device. FIG. 2 is a cross-sectional view of the electric valve device of FIG. 1. FIG. 3 is a view showing a valve shaft holder of the electric valve device of FIG. 2. FIG. 3A is a perspective view of the valve shaft holder, and FIG. 3B is a plan view of the valve shaft holder. FIG. 4 is a side view of a guide bush of the electric valve device of FIG. 2. FIG. 5 is a view showing a stopper member of the electric valve device of FIG. 2. FIG. 5A is a perspective view of the stopper member, and FIG. 5B is a plan view of the stopper member. FIG. 6 is a plan view of a valve shaft holder, a stopper member, a rotor, and a stator of the electric valve device of FIG. 2. In FIG. 6, the stator is schematically shown. Also, in FIG. 6, the magnetic poles of the rotor are schematically shown. FIG. 7 is a view for explaining a computer, a motor driver including a current circuit having a switching element, and a stepping motor of the electric valve device of FIG. 2. FIG. 8 is a view showing an example of the correspondence between the pulses input to the stepping motor and the target values of the phase A current and the phase B current. FIG. 9 is a view showing an example of the waveforms of the phase A current and the phase B current.

[0026] FIGS. 10 to 17 are views schematically showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator. FIGS. 10 to 17 show the case where pulses P[1] to P[8] are input to the stepping motor. In FIGS. 10 to 17, the stator is schematically shown. Also, in FIGS. 10 to 17, the magnetic poles of the rotor are schematically shown.

[0027] FIG. 18 is a diagram showing an example of the waveform of the B-phase current and the waveform of the back electromotive force generated in the B-phase coil. FIG. 19 is a diagram showing an example of a graph of the rotor rotation angle, the B-phase current, the back electromotive force generated in the B-phase coil, and the reciprocal of the off-time of the switching element related to the B-phase current. FIGS. 20 and 21 are diagrams showing an example of the waveform of the reciprocal of the off-time of the switching element when a drive current for rotating the rotor in the first direction is supplied. FIG. 20 shows the waveform in a state where the electric valve allows the rotation of the rotor in the first direction, and FIG. 21 shows the waveform in a state where the electric valve restricts the rotation of the rotor in the first direction. FIG. 22 is a diagram showing an example of the data table of the reference waveform of the reciprocal of the off-time. FIG. 23 is a diagram showing an example of the waveform (actual reciprocal waveform) of the reciprocal of the off-time and the reference waveform of the reciprocal of the off-time.

[0028] FIGS. 24 to 28 are flowcharts showing Operation Example 1 of the electric valve control device according to an embodiment of the present invention. FIG. 24 shows the main flow of Operation Example 1. FIG. 25 shows the preparation operation of Operation Example 1. FIGS. 26 and 27 show the warm-up operation of Operation Example 1. FIG. 28 shows the reference output operation of Operation Example 1.

[0029] FIGS. 29 to 32 are flowcharts showing Operation Example 2 of the electric valve control device according to an embodiment of the present invention. FIG. 29 shows the main flow of Operation Example 2. FIGS. 30 to 32 show the warm-up operation of Operation Example 2.

[0030] The electric valve device 1 according to the present embodiment is used, for example, as a flow control valve that controls the flow rate of a refrigerant, which is a fluid, in the refrigeration cycle of an air conditioning system.

[0031] FIG. 1 shows an example of an air conditioning system 100 mounted on a vehicle. The air conditioning system 100 has a compressor 101, a condenser 102, an electric valve device 1 (electric valve 5), and an evaporator 103 connected in sequence via a pipe 105. The electric valve device 1 is an expansion valve. The air conditioning system 100 has an air conditioning control device 110. The air conditioning control device 110 is communicably connected to the electric valve device 1. The air conditioning control device 110 controls the flow rate of the refrigerant flowing through the pipe 105 using the electric valve device 1.

[0032] As shown in FIG. 2, the electric valve device 1 includes an electric valve 5 and an electric valve control device 70.

[0033] The electric valve 5 includes a valve body 10, a can 20, a valve element 30, a drive mechanism 40, and a stator 60.

[0034] The valve body 10 includes a body member 11 and a connecting member 13. The body member 11 has a cylindrical shape. The body member 11 has a valve chamber 14, a valve port 17, and a valve seat 18. A first conduit 15 and a second conduit 16 are joined to the body member 11. The first conduit 15 is arranged along a direction orthogonal to the axis L (the left - right direction in FIG. 2) and is connected to the valve chamber 14. The second conduit 16 is arranged along the axis L direction (the up - down direction in FIG. 2) and is connected to the valve chamber 14 via the valve port 17. The valve port 17 is surrounded by an annular valve seat 18 in the valve chamber 14. The body member 11 has a circular fitting hole 11a. The fitting hole 11a is arranged on the upper end surface of the body member 11. The inner peripheral surface of the fitting hole 11a has a plane 11d facing leftward in FIG. 2. A through - hole 11b communicating with the valve chamber 14 is provided at 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 portion of the body member 11. The body member 11 and the connecting member 13 are made of a metal such as an aluminum alloy, stainless steel, or brass.

[0035] 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 connecting member 13.

[0036] The valve body 30 has a first shaft portion 31, a second shaft portion 32, and a valve portion 33. The first shaft portion 31 has a cylindrical shape. The second shaft portion 32 has a cylindrical shape. The diameter of the second shaft portion 32 is smaller than the diameter of the first shaft portion 31. The second shaft portion 32 is coaxially connected to the upper end portion 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 substantially conical shape in which the diameter decreases from top to bottom. The valve portion 33 is coaxially connected to the lower end portion 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.

[0037] 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 guide bush 43, a stopper member 44, and a fixture 45.

[0038] 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 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 pole and S pole is 15 degrees.

[0039] Figure 3 shows the valve shaft holder 42. The valve shaft holder 42 has a cylindrical shape. The lower end of the valve shaft holder 42 is open. An upper wall portion 42a is provided at the upper end of the valve shaft holder 42. The upper wall portion 42a has a shaft hole 42b. The valve shaft holder 42 is fitted into the fitting hole 41a of the rotor 41. The valve shaft holder 42 rotates together with the rotor 41. A movable stopper 42s is disposed at the lower end of the outer peripheral surface of the valve shaft holder 42. The movable stopper 42s is a protrusion that projects radially outward. The second shaft portion 32 of the valve body 30 is disposed in the shaft hole 42b so as to be movable in the axial direction of the axis L. A washer 46 is disposed on the lower surface of the upper wall portion 42a of the valve shaft holder 42. A closing spring 47 is disposed between the washer 46 and the 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.

[0040] Figure 4 shows the guide bush 43. The guide bush 43 has a base portion 43a and a support portion 43b. The base portion 43a has a cylindrical shape. The outer peripheral surface of the base portion 43a has a flat surface 43d. The base portion 43a is press-fitted into the fitting hole 11a of the main body member 11, and the flat surface 43d contacts the flat surface 11d of the fitting hole 11a. Thereby, the central axis of the main body member 11 and the central axis of the guide bush 43 coincide on the axis L, and the guide bush 43 is correctly positioned around the axis L with respect to the main body member 11. The support portion 43b has a cylindrical shape. The outer diameter of the support portion 43b is smaller than the outer diameter of the base portion 43a. The inner diameter of the support portion 43b is the same as the inner diameter of the base portion 43a. The support portion 43b is coaxially connected to the upper end 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 axial direction of the axis L.

[0041] Figure 5 shows the stopper member 44. The stopper member 44 has a stopper body 44a. The stopper body 44a has a cylindrical shape. An internal thread 44c is provided on the inner peripheral surface of the stopper body 44a. A fixed stopper 44s is disposed on the outer peripheral surface of the stopper body 44a. The fixed stopper 44s is a protrusion protruding radially outward. The internal thread 44c is screwed onto the male thread 43c until the stopper body 44a abuts against the base portion 43a of the guide bush 43. Thereby, the stopper member 44 is fixed to the guide bush 43. The fixed stopper 44s is fixed to the valve body 10.

[0042] The fixture 45 has a fixing portion 45a and a flange portion 45b. The fixing portion 45a has a stepped cylindrical shape. The second shaft portion 32 of the valve body 30 is disposed inside the fixing portion 45a. The fixing portion 45a is joined to the second shaft portion 32. The flange portion 45b is connected to the lower end portion of the fixing portion 45a. A return spring 48 is disposed outside the fixture 45. The return spring 48 is a coil spring.

[0043] The electric valve 5 has a drive mechanism 40 that is used without reducing the rotation of the rotor 41. The electric valve 5 may have a drive mechanism having a speed reduction mechanism that reduces the rotation of the rotor 41 instead of the drive mechanism 40.

[0044] The stator 60 has a cylindrical shape. The stator 60 has a phase-A stator 61 and a phase-B stator 62. In FIG. 6, the stator 60 is schematically shown.

[0045] The A-phase stator 61 has a plurality of claw-pole type pole teeth 61a, 61b on its inner circumference. 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 stator 61 has, for example, 12 pole teeth 61a and 12 pole teeth 61b. The angle between adjacent pole teeth 61a and 61b is 15 degrees. The A-phase stator 61 has an A-phase coil 61c. When the A-phase coil 61c is energized, the pole teeth 61a and 61b become magnetic poles with different polarities from each other.

[0046] The B-phase stator 62 has a plurality of claw-pole type pole teeth 62a, 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 stator 62 has, for example, 12 pole teeth 62a and 12 pole teeth 62b. The angle between adjacent pole teeth 62a and 62b is 15 degrees. The B-phase stator 62 has a B-phase coil 62c. When the B-phase coil 62c is energized, the pole teeth 62a and 62b become magnetic poles with different polarities from each other.

[0047] The A-phase stator 61 and the B-phase stator 62 are arranged coaxially. The A-phase stator 61 is in contact with the B-phase stator 62. The angle between the pole tooth 61a of the A-phase stator 61 and the pole tooth 62a of the B-phase stator 62 adjacent to each other when viewed from the direction of the axis L is 7.5 degrees. That is, the B-phase stator 62 is at a position rotated 7.5 degrees around the axis L with respect to the A-phase stator 61 from the position where the pole teeth 61a and 62a are aligned in the direction of the axis L.

[0048] 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.

[0049] The stepping motor 66 is connected to the electric valve control device 70. Specifically, as shown in FIG. 7, the terminals A1 and A2 of the phase A coil 61c and the terminals B1 and B2 of the phase B coil 62c are connected to the motor driver 77 of the electric valve control device 70.

[0050] When a pulse P (P[1] to P[8]) is 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 a 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".

[0051] Pulses P[1] to P[8] are sequentially input to the stepping motor 66. A phase current Ia, which is a drive current corresponding to the pulse P, is supplied to the phase A stator 61. A phase current Ib, which is a drive current corresponding to the pulse P, is supplied to the phase B stator 62. The combination of the phase A current Ia and the phase B current Ib is different for each pulse P. The number of combinations is 8, which is the number of patterns of the pulse P. "Pattern" is also referred to as "switching mode". The numbers (1 to 8) of the pulses P[1] to P[8] are pattern numbers for specifying the pulses P[1] to P[8]. For example, the period of the pulse P is 8 ms, and one period X including the pulses P[1] to P[8] is 64 ms. The excitation mode of the stepping motor 66 is 1-2 phase excitation. The step angle of the stepping motor 66 is 3.75 degrees.

[0052] A phase current target value Ita corresponding to the pulses P[1] to P[8] is set for the phase A current Ia. A phase current target value Itb corresponding to the pulses P[1] to P[8] is set for the phase B current Ib. FIG. 8 shows an example of the correspondence between the pulse P and the phase A current target value Ita and the phase B current target value Itb.

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

[0054] FIG. 9 schematically shows waveforms of phase A current Ia and phase B current Ib when pulse P is input to stepping motor 66 in ascending order. In FIG. 9, phase A current Ia is a current having the same magnitude and current direction as phase A current target value Ita, and phase B current Ib is a current having the same magnitude and current direction as phase B current target value Itb. In FIGS. 8 and 9, the symbol (+ / -) indicates the direction in which the current flows. \"+\" indicates the direction from terminal A1 to terminal A2, or the direction from terminal B1 to terminal B2. \"-\" indicates the direction from terminal A2 to terminal A1, or the direction from terminal B2 to terminal B1. \"0\" indicates that no current flows.

[0055] The energization period D(1) corresponds to pulses P[2], P[3], P[4], and in the energization period D(1), a phase B current Ib flowing from terminal B1 to terminal B2 is supplied to phase B coil 62c. The energization period D(2) corresponds to pulses P[4], P[5], P[6], and in the energization period D(2), a phase A current Ia flowing from terminal A2 to terminal A1 is supplied to phase A coil 61c. The energization period D(3) corresponds to pulses P[6], P[7], P[8], and in the energization period D(3), a phase B current Ib flowing from terminal B2 to terminal B1 is supplied to phase B coil 62c. The energization period D(4) corresponds to pulses P[8], P[1], P[2], and in the energization period D(4), a phase A current Ia flowing from terminal A1 to terminal A2 is supplied to phase A coil 61c.

[0056] FIGS. 10 to 17 show examples of the positional relationship between rotor 41 and stator 60 when pulses P[1] to P[8] are input. In FIGS. 10 to 17, in order to easily grasp the positional relationship between rotor 41 and stator 60 (phase A stator 61, phase B stator 62), black circles are attached to reference pole teeth 61a and the magnetic pole (S pole) of reference rotor 41.

[0057] When the rotor 41 is rotated in the first direction (clockwise in FIGS. 10 to 17), pulses P are cyclically input to the stepping motor 66 in ascending order (in the order of pulses P[1] to P[8]). When the rotor 41 rotates in the first direction, the rotor 41 and the valve shaft holder 42 move downward due to the screw feed action between the female screw 42c of the valve shaft holder 42 and the male screw 43c of the guide bush 43. The rotor 41 (valve shaft holder 42) presses 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 moves further downward. The valve body 30 does not move downward. Then, when the movable stopper 42s of the valve shaft holder 42 contacts the fixed stopper 44s of the stopper member 44, 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.

[0058] When the rotor 41 is rotated in the second direction opposite to the first direction (counterclockwise in FIGS. 10 to 17), pulses P are cyclically input to the stepping motor 66 in descending order (in the order of pulses P[8] to P[1]). When the rotor 41 rotates in the second direction, the rotor 41 and the valve shaft holder 42 move upward due to the screw feed action between the female screw 42c of the valve shaft holder 42 and the male screw 43c of the guide bush 43. The rotor 41 (valve shaft holder 42) presses the fixture 45 upward. The valve body 30 moves upward together with the fixture 45, and the valve body 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 (the opening degree of the valve port 17) is a predetermined set value in a predetermined flow rate measurement environment 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 and the like. 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 has the maximum opening degree.

[0059] 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 in the fully open position Rz, the rotor 41 is positioned at the reference position Rx. For example, the number of strokes Ns is 500. The number of pulses P for rotating the rotor 41 from the reference position Rx to the fully open position Rz is also the number of strokes Ns.

[0060] Based on the number of strokes Ns, an initialization number Ni is set. The initialization number Ni is the number of pulses P sufficient to rotate the rotor 41 from the fully open position Rz to the reference position Rx. That is, when the number of pulses P of the initialization number Ni is input to the stepping motor 66 regardless of the position of the rotor 41, the rotor 41 is positioned at the reference position Rx. The initialization number Ni is, for example, a number that is 1.05 to 1.3 times the number of strokes Ns.

[0061] Based on the number of strokes Ns, a preparation number Np and a warm-up number Nw are set. The preparation number Np and the warm-up number Nw are used in the operation (initialization operation) of positioning the rotor 41 at the reference position Rx. The preparation number Np is, for example, a number that is 0.05 to 0.3 times the number of strokes Ns. The warm-up number Nw is the same as the preparation number Np. The warm-up number Nw may be smaller than the preparation number Np, and is preferably a number that is 0.8 to 1 times the preparation number Np.

[0062] In the electric valve 5, 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 stator 61 and the B-phase stator 62) have their respective central axes coinciding with the axis L.

[0063] 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.

[0064] The non-volatile memory 75 stores data that needs to be retained even when the power is cut off. The non-volatile memory 75 is, for example, an EEPROM or a flash memory.

[0065] The communication device 76 is communicably connected to the air conditioner control device 110 via the wired communication bus 120. The air conditioner system 100 adopts a communication method such as, for example, a Local Interconnect Network (LIN) or a Controller Area Network (CAN). Note that the communication device 76 may be wirelessly communicably connected to the air conditioner control device 110.

[0066] The motor driver 77 is controlled by the computer 80 and supplies drive currents (phase A current Ia, phase B current Ib) to the stator 60 of the stepping motor 66.

[0067] The motor driver 77 is connected to the stator 60. Specifically, as shown in FIG. 7, the motor driver 77 is connected to the phase A coil 61c and the phase B coil 62c. The motor driver 77 supplies the phase A current Ia to the phase A coil 61c and supplies the phase B current Ib to the phase B coil 62c.

[0068] The motor driver 77 receives a pulse signal (PULSE) and a direction signal (DIR) from the computer 80. When the pulse signal is input while the direction signal corresponding to the first direction 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 pulse signal is input while the direction signal corresponding to the second direction is input to the motor driver 77, it corresponds to the pulse P being input to the stepping motor 66 in descending order.

[0069] As shown in FIG. 7, the motor driver 77 has H-bridge circuits 77A and 77B, and a current control unit 77C. The H-bridge circuits 77A and 77B are current circuits. The motor driver 77 drives the stepping motor 66 in a bipolar method.

[0070] The H-bridge circuit 77A is connected to the A-phase coil 61c. The H-bridge circuit 77A has switch elements SW11, SW12, SW13, and SW14 which are switch elements. When a current is passed from the terminal A1 to the terminal A2 of the A-phase coil 61c, the switches SW11 and SW14 are turned on (conductive state), and the switches SW12 and SW13 are turned off (non-conductive state). When a current is passed from the terminal A2 to the terminal A1 of the A-phase coil 61c, the switches SW12 and SW13 are turned on, and the switches SW11 and SW14 are turned off. The switches SW11, SW12, SW13, and SW14 are, for example, N-channel MOSFETs or P-channel MOSFETs, and both may be mixed.

[0071] After supplying the A-phase current Ia to the A-phase coil 61c, the switches SW11 and SW13 are turned off, and the switches SW12 and SW14 are turned on. Then, after the energy is attenuated in the circuit formed by the switches SW12 and SW14 and the A-phase coil 61c, the switches SW12 and SW14 are turned off.

[0072] The H-bridge circuit 77B is connected to the B-phase coil 62c. The H-bridge circuit 77B has switch elements SW21, SW22, SW23, and SW24 which are switch elements. When a current is passed from the terminal B1 to the terminal B2 of the B-phase coil 62c, the switches SW21 and SW24 are turned on, and the switches SW22 and SW23 are turned off. When a current is passed from the terminal B2 to the terminal B1 of the B-phase coil 62c, the switches SW22 and SW23 are turned on, and the switches SW21 and SW24 are turned off. The switches SW21, SW22, SW23, and SW24 are, for example, N-channel MOSFETs or P-channel MOSFETs, and both may be mixed.

[0073] After supplying the B-phase current Ib to the B-phase coil 62c, turn off switches SW21 and SW23, and turn on switches SW22 and SW24. Then, after attenuating the energy in the circuit formed by switches SW22, SW24, and the B-phase coil 62c, turn off switches SW22 and SW24.

[0074] The current control unit 77C controls the H-bridge circuits 77A and 77B according to the pulse signal and the direction signal input from the computer 80. The current control unit 77C outputs an A-phase switch state signal (A-STATE) indicating the states of the switches SW11, SW12, SW13, and SW14 of the H-bridge circuit 77A. The current control unit 77C outputs a B-phase switch state signal (B-STATE) indicating the states of the switches SW21, SW22, SW23, and SW24 of the H-bridge circuit 77B. The A-phase switch state signal and the B-phase switch state signal are binary signals. The binary signal has a first value (for example, H value) and a second value (for example, L value).

[0075] The current control unit 77C controls the H-bridge circuits 77A and 77B by a fixed ripple current control method.

[0076] 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 switches SW12 and SW13. (2) The current control unit 77C determines the magnitude of the A-phase current Ia. (2-1) When the A-phase current Ia is smaller than the A-phase current lower limit value Isa, the current control unit 77C turns on switches SW11 and SW14. The A-phase current lower limit value Isa is smaller than the A-phase current target value Ita by a fixed value ΔI. (2-2) When the A-phase current Ia reaches the A-phase current target value Ita, the current control unit 77C turns off switches SW11 and SW14. (3) When switches SW11 and SW14 are on, the current control unit 77C sets the A-phase switch state signal to the first value, and when switches SW11 and SW14 are off, the current control unit 77C sets the A-phase switch state signal to the second value.

[0077] 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 determines the magnitude of the A-phase current Ia. (2-1) When the A-phase current Ia is smaller than the A-phase current lower limit value Isa, the current control unit 77C turns on the switches SW12 and SW13. (2-2) When the A-phase current Ia reaches the A-phase current target value Ita, the current control unit 77C turns off the switches SW12 and SW13. (3) When the switches SW12 and SW13 are on, the current control unit 77C sets the A-phase switch state signal to the first value, and when the switches SW12 and SW13 are off, the current control unit 77C sets the A-phase switch state signal to the second value.

[0078] 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 determines the magnitude of the B-phase current Ib. (2-1) When the B-phase current Ib is smaller than the B-phase current lower limit value Isb, the current control unit 77C turns on the switches SW21 and SW24. The B-phase current lower limit value Isb is smaller than the B-phase current target value Itb by a fixed value ΔI. (2-2) When the B-phase current Ib reaches the B-phase current target value Itb, the current control unit 77C turns off the switches SW21 and SW24. (3) When the switches SW21 and SW24 are on, the current control unit 77C sets the B-phase switch state signal to the first value, and when the switches SW21 and SW24 are off, the current control unit 77C sets the B-phase switch state signal to the second value.

[0079] 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 determines the magnitude of the B-phase current Ib. (2-1) When the B-phase current Ib is smaller than the B-phase current lower limit value Isb, the current control unit 77C turns on the switches SW22 and SW23. (2-2) When the B-phase current Ib reaches the B-phase current target value Itb, the current control unit 77C turns off the switches SW22 and SW23. (3) When the switches SW22 and SW23 are on, the current control unit 77C sets the B-phase switch state signal to the first value, and when the switches SW22 and SW23 are off, the current control unit 77C sets the B-phase switch state signal to the second value.

[0080] Figure 18 shows an example of the waveform of the B-phase current Ib and the waveform of the back electromotive force (BEMF) generated in the B-phase coil 62c in the fixed ripple current control method. The back electromotive force is the voltage generated in the B-phase coil 62c by the rotation of the rotor 41. The B-phase current Ib flows from the terminal B1 to the terminal B2. In the periods T(1) to T(3), when the B-phase current Ib is smaller than the B-phase current lower limit value Isb, the switches SW21 and SW24 are turned on, and the B-phase current Ib increases (Ton). When the B-phase current Ib reaches the B-phase current target value Itb, the switches SW21 and SW24 are turned off, and the B-phase current Ib decreases (Toff). The on / off of the switches SW21 and SW24 is repeated according to the magnitude of the B-phase current Ib. The on-time and off-time of the switches SW21 and SW24 are variable. The off-time Toff of the switches SW21 and SW24 is represented by the following formula (1).

[0081]

Equation

[0082] I is the B-phase current Ib supplied to the B-phase coil 62c, R is the resistance of the B-phase coil 62c, L is the inductance of the B-phase coil 62c, and ΔI is a fixed value. Equation (1) shows that Toff has a relationship with the BEMF. That is, as shown in FIG. 18, when the BEMF is low, Toff is short, and when the BEMF is high, Toff is long. Even when the direction of the B-phase current Ib is from terminal B2 to terminal B1, Equation (1) holds. Also, Equation (1) holds for the off-time of the switching element related to the A-phase current Ia.

[0083] The computer 80 is a microcomputer for embedded devices in which a CPU, ROM, RAM, input / output interface, A / D converter, etc. are integrated 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 functions as a rotation control unit 81, an off-time acquisition unit 82, a state determination unit 83, and a reference waveform setting unit 84 by the CPU executing a program stored in the ROM.

[0084] 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 a command received from the air conditioner control device 110, and supplies the A-phase current Ia and the B-phase current Ib to the stator 60 (A-phase coil 61c, B-phase coil 62c).

[0085] The off-time acquisition unit 82 acquires the on-time and off-time of the switching element when the A-phase current Ia and the B-phase current Ib for rotating the rotor 41 in the first direction are supplied to the stator 60.

[0086] The off-time acquisition unit 82 acquires the on-time and off-time of the switching element related to the B-phase current Ib based on the B-phase switch state signal during the energization periods D(1) and D(3). The off-time acquisition unit 82 acquires the on-time and off-time of the switching element related to the A-phase current Ia based on the A-phase switch state signal during the energization periods D(2) and D(4). The off-time acquisition unit 82 calculates the reciprocal of the off-time acquired during the energization periods D(1) to D(4).

[0087] The energization period D(1) includes consecutive periods T(1) to T(n) having an on-time and an off-time. The off-time in the period T(h) (h = 1 to n) is Toff(h). FIG. 18 shows an example of the periods T(1) to T(3). When the energization period D(1) ends, the off-time acquisition unit 82 sets the reciprocal of the off-time in the period T(h) as 1 / Toff(h). The off-time acquisition unit 82, for example, sets the reciprocal of the off-time in the period T(1) as 1 / Toff(1), the reciprocal of the off-time in the period T(2) as 1 / Toff(2), and the reciprocal of the off-time in the period T(3) as 1 / Toff(3). Then, the off-time acquisition unit 82 acquires the reciprocal of the off-time at a predetermined time interval from the start to the end of the energization period D(1). The predetermined time interval is, for example, 400 μs. The energization period D(1) corresponds to the pulses P[2], P[3], P[4] and is 24 ms. The off-time acquisition unit 82 acquires 60 reciprocals of the off-time during the energization period D(1). The off-time acquisition unit 82 may exclude the period T corresponding to the switching timing of the pulse P where the B-phase current Ib is relatively unstable and the period T close to the switching timing from the acquisition targets of the reciprocal of the off-time. The plurality of reciprocals of the off-time acquired by the off-time acquisition unit 82 is the waveform of the reciprocal of the off-time during the energization period D(1). In the following description, the waveform of the reciprocal of the off-time acquired by the off-time acquisition unit 82 is also referred to as the "actual reciprocal waveform".

[0088] In this specification, a "waveform" refers to the temporal change of a physical quantity at a fixed point. The physical quantity includes the reciprocal of the off-time. When visualizing a "waveform", it is represented 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". Further, the "area of the waveform" is the area of the region surrounded by the waveform and the horizontal axis when the waveform is represented on a coordinate plane with the physical quantity on the vertical axis and time on the horizontal axis corresponding to the physical quantity 0.

[0089] The off-time acquisition unit 82 acquires the inverse reciprocal waveform in the same manner as in the energization period D(1) even in the energization periods D(2) to D(4).

[0090] The state determination unit 83 determines the state of the electric valve 5 based on the reciprocal of the off-time acquired by the off-time acquisition unit 82 in the initialization operation. The electric valve 5 has a first rotation allowable state Sp1 and a first rotation regulation state Sr1. The first rotation allowable state Sp1 is a state in which the rotor 41 has not reached the reference position Rx and the rotation of the rotor 41 in the first direction is allowed. The first rotation regulation state Sr1 is a state in which the rotor 41 has reached the reference position Rx and the movable stopper 42s has come into contact with the fixed stopper 44s and the rotation of the rotor 41 in the first direction is regulated.

[0091] FIG. 19 shows an example of a graph (waveform) of the rotation angle of the rotor 41, the B-phase current Ib, the back electromotive force (BEMF) generated in the B-phase coil 62c, and the reciprocal of the off-time (1 / Toff) of the switching element related to the B-phase current Ib. In FIG. 19, the waveform surrounded by the dashed-dotted line is an enlarged part of the waveform of the B-phase current Ib.

[0092] In FIG. 19, as the rotation angle of the rotor 41 increases, the rotor 41 approaches the reference position Rx. Then, at the time tx, the rotor 41 reaches the reference position Rx and the rotation of the rotor 41 in the first direction is regulated. Before the time tx, the electric valve 5 is in the first rotation allowable state Sp1, and after the time tx, the electric valve 5 is in the first rotation regulation state Sr1.

[0093] Figure 19 shows the following regarding the BEMF waveform. The BEMF waveforms during the energization period D(1) before time tx are the same. The BEMF waveforms during the energization period D(3) before time tx are the same. The BEMF waveforms during the energization period D(1) after time tx are the same. The BEMF waveforms during the energization period D(3) after time tx are the same. The BEMF waveform during the energization period D(1) after time tx is different from the BEMF waveform during the energization period D(1) before time tx. The BEMF waveform during the energization period D(3) after time tx is different from the BEMF waveform during the energization period D(3) before time tx.

[0094] Figure 19 shows the following regarding the waveform of 1 / Toff (actual reciprocal waveform). The actual reciprocal waveforms during the energization period D(1) before time tx are the same. The actual reciprocal waveforms during the energization period D(3) before time tx are the same. The actual reciprocal waveforms during the energization period D(1) after time tx are the same. The actual reciprocal waveforms during the energization period D(3) after time tx are the same. The actual reciprocal waveform during the energization period D(1) before time tx is the same as the actual reciprocal waveform during the energization period D(3) before time tx. The actual reciprocal waveform during the energization period D(1) after time tx is different from the actual reciprocal waveform during the energization period D(3) after time tx. The actual reciprocal waveform during the energization period D(1) after time tx is different from the actual reciprocal waveform during the energization period D(1) before time tx. The actual reciprocal waveform during the energization period D(3) after time tx is different from the actual reciprocal waveform during the energization period D(3) before time tx.

[0095] The above also applies to the waveform of the back electromotive force generated in the A-phase coil 61c and the waveform of the reciprocal of the off-time of the switching element related to the A-phase current Ia.

[0096] Therefore, the state determination unit 83 can determine the state of the motor-operated valve 5 based on the reciprocal of the off-time.

[0097] Also, the refrigerant is introduced inside the can 20. The refrigerant contains refrigeration oil. The refrigeration oil has a high viscosity when the temperature of the refrigerant is low and a low viscosity when the temperature of the refrigerant is high. Therefore, immediately after the start of operation of the motor-operated valve 5, the temperature of the refrigerant is low, and the resistance to the rotation of the rotor 41 is large. As the operation of the motor-operated valve 5 progresses and the refrigerant is heated by the heat of the stator 60, the resistance becomes small. Since the back electromotive force is generated by the rotation of the rotor 41, the waveform of the reciprocal of the off-time of the switching element (actual reciprocal waveform) may change according to the temperature rise of the motor-operated valve 5 (refrigerant).

[0098] From this, the following matters are inferred. The actual reciprocal waveform when the motor-operated valve 5 is cold is different from the actual reciprocal waveform when the motor-operated valve 5 is warm. The actual reciprocal waveform gradually changes until the motor-operated valve 5 is sufficiently warmed, and the actual reciprocal waveform stabilizes when the motor-operated valve 5 is sufficiently warmed.

[0099] Therefore, in the initialization operation of the motor-operated valve 5, a stable actual reciprocal waveform can be obtained by rotating the rotor 41 to warm the motor-operated valve 5.

[0100] Fig. 20 shows an example of the actual reciprocal waveform in the energization period D(1) when the rotor 41 is rotated in the first direction in the motor-operated valve 5 in the first rotation allowable state Sp1. Fig. 21 shows an example of the actual reciprocal waveform in the energization period D(1) when the rotor 41 is rotated in the first direction in the motor-operated valve 5 in the first rotation restriction state Sr1.

[0101] The state determination unit 83 determines the state of the motor-operated valve 5 by comparing the actual reciprocal waveform with the reference waveform of the reciprocal of the off-time. In the following description, the reference waveform of the reciprocal of the off-time is also simply referred to as the "reference waveform".

[0102] Further, the state determination unit 83 compares the actual reciprocal waveform with the reference waveform to determine whether the actual reciprocal waveform is similar to the reference waveform.

[0103] The reference waveform setting unit 84 sets the reference waveform. The reference waveform is set based on the reciprocal of the off-time acquired by the off-time acquisition unit 82. The reference waveform setting unit 84 stores the reference waveform in the non-volatile memory 75. The reference waveform setting unit 84 may store the reference waveform in the RAM of the computer 80.

[0104] One reference waveform is set for each of the energization periods D(1) to D(4).

[0105] The reference waveform in the energization period D(1) is set based on the actual reciprocal waveform when the B-phase current Ib is supplied to the B-phase coil 62c in accordance with the pulses P[2], P[3], P[4] input to the stepping motor 66 when the rotor 41 is rotated in the first direction.

[0106] The reference waveform in the energization period D(2) is set based on the actual reciprocal waveform when the A-phase current Ia is supplied to the A-phase coil 61c in accordance with the pulses P[4], P[5], P[6] input to the stepping motor 66 when the rotor 41 is rotated in the first direction.

[0107] The reference waveform in the energization period D(3) is set based on the actual reciprocal waveform when the B-phase current Ib is supplied to the B-phase coil 62c in accordance with the pulses P[6], P[7], P[8] input to the stepping motor 66 when the rotor 41 is rotated in the first direction.

[0108] The reference waveform in the energization period D(4) is set based on the actual reciprocal waveform when the A-phase current Ia is supplied to the A-phase coil 61c in accordance with the pulses P[8], P[1], P[2] input to the stepping motor 66 when the rotor 41 is rotated in the first direction.

[0109] The reference waveform is stored in the non-volatile memory 75 as a data table. In the non-volatile memory 75, reference waveform tables C[1] to C[4] that are reference waveforms during the energization periods D(1) to D(4) are stored.

[0110] FIG. 22 shows an example of the reference waveform table C[1]. In the reference waveform table C[1], a time t at a predetermined interval from the start time (time 0) of the energization period D(1) and a reference value rv that is the reciprocal of the off time at the time t are associated with each other. The interval of the time t is the same as the time interval (400 μs) at which the off time acquisition unit 82 acquires the reciprocal of the off time. The time t corresponds to the time (acquisition time) at which the off time acquisition unit 82 acquires the reciprocal of the off time. The reference waveform table C[1] has 60 pairs of the time t and the reference value rv. In FIG. 22, the unit of the time t is μs. The unit of the reference value rv is none. The units of the time t and the reference value rv may be unique units. The reference waveform tables C[2] to D[4] also have the same structure as the reference waveform table C[1].

[0111] The state determination unit 83 calculates a value (difference degree index value sv) indicating the degree of difference between the actual reciprocal waveform and the reference waveform. The larger the difference degree index value sv, the greater the degree of difference between the actual reciprocal waveform and the reference waveform.

[0112] When the energization period D(k) (k = 1 to 4) ends, the state determination unit 83 acquires the reciprocal v of the off time acquired by the off time acquisition unit 82 and the reference value rv associated with the time t corresponding to the acquisition time tv of the reciprocal v in the reference waveform table C[k]. The state determination unit 83 calculates a value (difference value dv) obtained by subtracting the reference value rv from the reciprocal v. The state determination unit 83 calculates a value (intermediate value dv2) obtained by squaring the difference value dv. The state determination unit 83 calculates a difference degree index value sv[k] by adding up the plurality of intermediate values dv2 calculated for the energization period D(k).

[0113] FIG. 23 shows an example of the actual reciprocal waveform (solid line) and the reference waveform (dashed line) during the energization period D(1). In FIG. 23, the length of the vertical line connecting the actual reciprocal waveform and the reference waveform corresponds to the difference value dv used for calculating the dissimilarity index value sv[1].

[0114] When the reciprocal v of the off-time obtained at the acquisition time tv between the start time t1 and the end time t2 of the energization period D is denoted as v[tv], and the reference value rv associated with the time t corresponding to the acquisition time tv in the reference waveform table C is denoted as rv[tv], the dissimilarity index value sv is represented by the following formula (2).

[0115]

Equation

[0116] The state determination unit 83 determines the state of the motor-operated valve 5 based on the dissimilarity index value sv[k]. Specifically, the state determination unit 83 compares the dissimilarity index value sv[k] with a predetermined dissimilarity determination value H. The state determination unit 83 determines whether the motor-operated valve 5 is in the first rotation allowable state Sp1 or the first rotation restriction state Sr1 based on the comparison result between the dissimilarity index value sv[k] and the dissimilarity determination value H. The motor-operated valve control device 70 may have a dissimilarity determination value H[k] corresponding to the dissimilarity index value sv[k]. Each dissimilarity determination value H[k] may be the same value or different values from each other.

[0117] In addition, the state determination unit 83 determines whether the actual reciprocal waveform and the reference waveform used for calculating the dissimilarity index value sv[k] are similar. Specifically, the state determination unit 83 compares the dissimilarity index value sv[k] with a predetermined similarity determination value G. The state determination unit 83 determines whether the actual reciprocal waveform and the reference waveform are similar based on the comparison result between the dissimilarity index value sv[k] and the similarity determination value G. The motor-operated valve control device 70 may have a similarity determination value G[k] corresponding to the dissimilarity index value sv[k]. Each similarity determination value G[k] may be the same value or different values from each other.

[0118] Next, an example of the initialization operation of the electric valve control device 70 (operation example 1) will be described with reference to FIGS. 24 to 28.

[0119] When the electric valve control device 70 (specifically, the computer 80) receives an initialization command from the air conditioner control device 110 (S100), it invalidates the reference waveform stored in the non-volatile memory 75 and then performs an initialization operation. The initialization operation includes a preparation operation (S200), a warm-up operation (S400), and a reference output operation (S600). The preparation operation, the warm-up operation, and the reference output operation correspond to a preparation step, a warm-up step, and a reference output step, respectively.

[0120] (Preparation operation) In the preparation operation, the electric valve control device 70 starts inputting the pulses P to the stepping motor 66 in descending order (Y in S210, S220) to rotate the rotor 41 in the second direction. When the number of pulses P input to the stepping motor 66 in the preparation operation reaches the preparation number Np (N in S220), the electric valve control device 70 stops inputting the pulses P to the stepping motor 66 (S230). The electric valve control device 70 ends the preparation operation and starts the warm-up operation.

[0121] (Warm-up operation) When starting the warm-up operation, the reference waveform is not set. "Not set" includes that the reference waveform has never been set, that the reference waveform has been set but is overwritten by a newly set reference waveform without being used even once, and that the reference waveform has been set but is recognized as invalid.

[0122] During the warm-up operation, the electric valve control device 70 starts inputting pulses P to the stepping motor 66 in ascending order (Y in S410 and S420), and rotates the rotor 41 in the first direction. When the number of pulses P input to the stepping motor 66 in the warm-up operation reaches K (N in S420), the electric valve control device 70 acquires the actual inverse waveform (S430) and sets the reference waveform (S440). The acquisition of the actual inverse waveform starts from the first energization period D after the K-th input pulse P in the warm-up operation. K is a natural number of 1 or more. In the electric valve control device 70, K = 1. It is preferable that K is a value equal to or less than half of the number of warm-up operations Nw.

[0123] In steps S430 and S440, the electric valve control device 70 acquires the actual inverse waveform during the energization period D(k) (k = 1 to 4), and stores the actual inverse waveform during the energization period D(k) as the reference waveform (reference waveform table C[k]) in the non-volatile memory 75. That is, the electric valve control device 70 sets the reference waveform.

[0124] When the reference waveform is set, the electric valve control device 70 starts the determination operation (S450 to S500).

[0125] The electric valve control device 70 acquires the actual inverse waveform during the energization period D(k) (S450). The electric valve control device 70 calculates the difference index value sv[k] using the actual inverse waveform during the energization period D(k) and the reference waveform (reference waveform table C[k]) (S460).

[0126] The electric valve control device 70 determines whether the actual inverse waveform and the reference waveform are similar (S470).

[0127] Specifically, the electric valve control device 70 compares the difference index value sv[k] with the similarity determination value G. When the difference index value sv[k] is equal to or less than the similarity determination value G, the electric valve control device 70 determines that the actual inverse waveform during the energization period D(k) is similar to the reference waveform. When the difference index value sv[k] is greater than the similarity determination value G, the electric valve control device 70 determines that the actual inverse waveform during the energization period D(k) is not similar to the reference waveform.

[0128] When the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) is similar to the reference waveform (Y in S480), it stores the actual reciprocal waveform as a new reference waveform (reference waveform table C[k]) in the non-volatile memory 75 (S490).

[0129] When the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) is not similar to the reference waveform (N in S480), it maintains the current reference waveform (reference waveform table C[k]). That is, the electric valve control device 70 does not update the reference waveform.

[0130] When the number of pulses P input to the stepping motor 66 in the warm-up operation is less than the warm-up number Nw (Y in S500), the electric valve control device 70 repeats the above operations (S450 to S500).

[0131] When the number of pulses P input to the stepping motor 66 in the warm-up operation reaches the warm-up number Nw (N in S500), the electric valve control device 70 ends the warm-up operation and starts the reference setting operation.

[0132] (Reference setting operation) In the reference setting operation, following the warm-up operation, the electric valve control device 70 inputs pulses P to the stepping motor 66 in ascending order to rotate the rotor 41 in the first direction.

[0133] The electric valve control device 70 acquires the actual reciprocal waveform during the energization period D(k) (S610). The electric valve control device 70 calculates the difference index value sv[k] using the actual reciprocal waveform and the reference waveform (reference waveform table C[k]) during the energization period D(k) (S620).

[0134] The electric valve control device 70 determines the state of the electric valve 5 (S630).

[0135] Specifically, the electric valve control device 70 compares the degree-of-difference index value sv[k] with the degree-of-difference determination value H, and compares the degree-of-difference index value sv[j] calculated immediately before the degree-of-difference index value sv[k] (when k = 2, 3, 4, j = k - 1; when k = 1, j = 4) with the degree-of-difference determination value H. When the degree-of-difference index value sv[k] is greater than or equal to the degree-of-difference determination value H and the degree-of-difference index value sv[j] is greater than or equal to the degree-of-difference determination value H, the electric valve control device 70 determines that the electric valve 5 is in the first rotation restriction state Sr1. When the degree-of-difference index value sv[k] is less than the degree-of-difference determination value H, or when the degree-of-difference index value sv[j] is less than the degree-of-difference determination value H, the electric valve control device 70 determines that the electric valve 5 is in the first rotation allowable state Sp1.

[0136] Alternatively, the electric valve control device 70 may determine the state of the electric valve 5 by comparing only the degree-of-difference index value sv[k] with the degree-of-difference determination value H. Specifically, the electric valve control device 70 compares the degree-of-difference index value sv[k] related to the period X[n] (n is a natural number) including the pulses P[1] to P[8] with the degree-of-difference determination value H, and compares the degree-of-difference index value sv[k] related to the period X[n - 1] immediately before the period X[n] with the degree-of-difference determination value H. When the degree-of-difference index value sv[k] related to the period X[n] is greater than or equal to the degree-of-difference determination value H and the degree-of-difference index value sv[k] related to the period X[n - 1] is greater than or equal to the degree-of-difference determination value H, the electric valve control device 70 determines that the electric valve 5 is in the first rotation restriction state Sr1. Note that when all of the plurality of degree-of-difference index values sv[k] related to three or more consecutive periods X are greater than or equal to the degree-of-difference determination value H, the electric valve control device 70 may determine that the electric valve 5 is in the first rotation restriction state Sr1. When the degree-of-difference index value sv[k] related to the period X[n] is less than the degree-of-difference determination value H, or when the degree-of-difference index value sv[k] related to the period X[n - 1] is less than the degree-of-difference determination value H, the electric valve control device 70 determines that the electric valve 5 is in the first rotation allowable state Sp1.

[0137] When the electric valve control device 70 determines that the rotor 41 is positioned at the reference position Rx when the electric valve 5 is in the first rotation restriction state Sr1 (Y in S640), the electric valve control device 70 notifies the air conditioner control device 110 of the success of the initialization operation (S660) and stops the input of the pulse P to the stepping motor 66 (S680). The electric valve control device 70 ends the reference setting operation (initialization operation).

[0138] When the electric valve 5 is in the first rotation allowable state Sp1 and the number of pulses P input to the stepping motor 66 in the warm-up operation and the reference setting operation is less than or equal to the initialization number Ni (N in S640, N in S650), the electric valve control device 70 repeats the above operations (S610 to S650).

[0139] When the electric valve 5 is in the first rotation allowable state Sp1 and the number of pulses P input to the stepping motor 66 in the warm-up operation and the reference setting operation exceeds the initialization number Ni (N in S640, Y in S650), the electric valve control device 70 determines that the electric valve 5 is faulty. Then, the electric valve control device 70 notifies the air conditioner control device 110 of the failure of the initialization operation (S670) and stops the input of the pulse P to the stepping motor 66 (S680). The electric valve control device 70 ends the reference setting operation (initialization operation). Note that the electric valve control device 70 may perform the above determination operation during the reference setting operation. Specifically, the same operations as steps S460 to S490 of the warm-up operation are performed immediately before step S620 of the reference setting operation.

[0140] When the initialization operation is successful, the rotor 41 is positioned at the reference position Rx. When the electric valve control device 70 rotates the rotor 41 at the reference position Rx in the second direction, the pulse P is input to the stepping motor 66 in descending order.

[0141] In Operation Example 1, steps S430, S450, and S610 correspond to the off-time acquisition process, steps S440 and S490 correspond to the reference waveform setting process, and step S630 corresponds to the state determination process.

[0142] Next, another example of the initialization operation of the electric valve control device 70 (operation example 2) will be described with reference to FIGS. 29 to 30.

[0143] In operation example 2, a reference waveform (reference waveform table C[k]), a first reference waveform (first reference waveform table C1[k]), and a second reference waveform (second reference waveform table C2[k]) are stored in the non-volatile memory 75. The first reference waveform table C1[k] and the second reference waveform table C2[k] have the same configuration as the reference waveform table C[k].

[0144] When the electric valve control device 70 receives an initialization command from the air conditioner control device 110 (S100), it invalidates the reference waveform, the first reference waveform, and the second reference waveform stored in the non-volatile memory 75, and then performs an initialization operation. The initialization operation includes a preparation operation (S200), a warm-up operation (S700), and a reference output operation (S600). In operation example 2, since the preparation operation and the reference output operation are the same as those in operation example 1, detailed descriptions thereof are omitted.

[0145] (Warm-up operation) When starting the warm-up operation, the reference waveform, the first reference waveform, and the second reference waveform are not set.

[0146] In the warm-up operation, the electric valve control device 70 starts inputting pulses P to the stepping motor 66 in ascending order (Y in S710, S720), and rotates the rotor 41 in the first direction. When the number of pulses P input to the stepping motor 66 in the warm-up operation reaches K (N in S720), the electric valve control device 70 acquires the actual reciprocal waveform (S730) and sets the first reference waveform (S740). The acquisition of the actual reciprocal waveform starts from the first energization period D after the K-th input pulse P in the warm-up operation.

[0147] In steps S730 and S740, the electric valve control device 70 acquires the actual reciprocal waveform during the energization period D(k), and stores the actual reciprocal waveform during the energization period D(k) in the non-volatile memory 75 as the first reference waveform (first reference waveform table C1[k]). That is, the electric valve control device 70 sets the first reference waveform.

[0148] When the first reference waveform is set, the electric valve control device 70 starts the first determination operation (S750 to S930).

[0149] The electric valve control device 70 acquires the actual reciprocal waveform during the energization period D(k) (S750). The electric valve control device 70 calculates the first difference index value sv1[k] using the actual reciprocal waveform during the energization period D(k) and the first reference waveform (first reference waveform table C1[k]) (S760). The electric valve control device 70 calculates the first difference index value sv1[k] in the same way as the difference index value sv[k].

[0150] The electric valve control device 70 determines whether the actual reciprocal waveform and the first reference waveform are similar (S770).

[0151] Specifically, the electric valve control device 70 compares the first difference index value sv1[k] with the similarity determination value G. When the first difference index value sv1[k] is less than or equal to the similarity determination value G, the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) is similar to the first reference waveform. When the first difference index value sv1[k] is greater than the similarity determination value G, the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) is not similar to the first reference waveform.

[0152] When the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) is similar to the first reference waveform (Y in S780), it stores the actual reciprocal waveform in the non-volatile memory 75 as the new first reference waveform (first reference waveform table C1[k]) (S790).

[0153] When the electric valve control device 70 first determines that the actual reciprocal waveform during the energization period D(k) does not resemble the first reference waveform (N in S780), it stores the actual reciprocal waveform as the second reference waveform (second reference waveform table C2[k]) in the non-volatile memory 75 (S820). That is, the electric valve control device 70 sets the second reference waveform.

[0154] When the number of pulses P input to the stepping motor 66 during the warm-up operation is less than the warm-up number Nw (Y in S800), the electric valve control device 70 repeats the above operations (S750 to S800).

[0155] When the number of pulses P input to the stepping motor 66 during the warm-up operation reaches the warm-up number Nw (N in S800), the electric valve control device 70 sets the first reference waveform (first reference waveform table C1[k]) as the reference waveform (reference waveform table C[k]) (S810). The electric valve control device 70 ends the warm-up operation and starts the reference setting operation.

[0156] When the second reference waveform is set, the electric valve control device 70 starts the second determination operation (S830 to S930).

[0157] The electric valve control device 70 acquires the actual reciprocal waveform during the energization period D(k) (S830). The electric valve control device 70 calculates the first difference index value sv1[k] using the actual reciprocal waveform during the energization period D(k) and the first reference waveform (first reference waveform table C1[k]), and calculates the second difference index value sv2[k] using the actual reciprocal waveform during the energization period D(k) and the second reference waveform (second reference waveform table C2[k]) (S840). The electric valve control device 70 calculates the first difference index value sv1[k] and the second difference index value sv2[k] in the same way as the difference index value sv[k].

[0158] The electric valve control device 70 determines whether the actual reciprocal waveform and the first reference waveform are similar, and determines whether the actual reciprocal waveform and the second reference waveform are similar (S850).

[0159] Specifically, the electric valve control device 70 compares the first phase difference index value sv1[k] with the similarity determination value G. When the first phase difference index value sv1[k] is less than or equal to the similarity determination value G, the electric valve control device 70 determines that the actual reciprocal waveform in the energization period D(k) is similar to the first reference waveform. When the first phase difference index value sv1[k] is greater than the similarity determination value G, the electric valve control device 70 determines that the actual reciprocal waveform in the energization period D(k) is not similar to the first reference waveform.

[0160] The electric valve control device 70 compares the second phase difference index value sv2[k] with the similarity determination value G. When the second phase difference index value sv2[k] is less than or equal to the similarity determination value G, the electric valve control device 70 determines that the actual reciprocal waveform in the energization period D(k) is similar to the second reference waveform. When the second phase difference index value sv2[k] is greater than the similarity determination value G, the electric valve control device 70 determines that the actual reciprocal waveform in the energization period D(k) is not similar to the second reference waveform.

[0161] When the electric valve control device 70 determines that the actual reciprocal waveform in the energization period D(k) is similar to the first reference waveform and determines that the actual reciprocal waveform in the energization period D(k) is not similar to the second reference waveform (Y in S860 and N in S870), the electric valve control device 70 stores the actual reciprocal waveform as a new first reference waveform (first reference waveform table C1[k]) in the non-volatile memory 75 (S900).

[0162] When the electric valve control device 70 determines that the actual reciprocal waveform in the energization period D(k) is not similar to the first reference waveform and determines that the actual reciprocal waveform in the energization period D(k) is similar to the second reference waveform (N in S860 and Y in S880), the electric valve control device 70 stores the actual reciprocal waveform as a new second reference waveform (second reference waveform table C2[k]) in the non-volatile memory 75 (S910).

[0163] When the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) does not resemble the first reference waveform and also determines that the actual reciprocal waveform during the energization period D(k) does not resemble the second reference waveform (N in S860, N in S880), it maintains the current first reference waveform (first reference waveform table C1[k]) and also maintains the current second reference waveform (second reference waveform table C2[k]).

[0164] When the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) resembles the first reference waveform and also determines that the actual reciprocal waveform during the energization period D(k) resembles the second reference waveform (Y in S860, Y in S870), it determines which of the first reference waveform and the second reference waveform the actual reciprocal waveform resembles (S890).

[0165] Specifically, the electric valve control device 70 compares the first difference index value sv1[k] and the second difference index value sv2[k]. When the first difference index value sv1[k] is less than or equal to the second difference index value sv2[k] (sv1[k] ≦ sv2[k]), the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) resembles the first reference waveform more than the second reference waveform. When the first difference index value sv1[k] is greater than the second difference index value sv2[k] (sv1[k] > sv2[k]), the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) resembles the second reference waveform more than the first reference waveform.

[0166] When the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) resembles the first reference waveform more than the second reference waveform (Y in S890), it stores the actual reciprocal waveform as a new first reference waveform (first reference waveform table C1[k]) in the non-volatile memory 75 (S900).

[0167] When the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) resembles the second reference waveform more than the first reference waveform (N in S890), it stores the actual reciprocal waveform as a new second reference waveform (second reference waveform table C2[k]) in the non-volatile memory 75 (S910).

[0168] In addition, when the electric valve control device 70 determines that the actual reciprocal waveform during the energization period D(k) resembles the first reference waveform and also determines that the actual reciprocal waveform during the energization period D(k) resembles the second reference waveform (Y in S860 and Y in S870), the actual reciprocal waveform may be stored in the non-volatile memory 75 as a new first reference waveform (first reference waveform table C1[k]), and the actual reciprocal waveform may be stored in the non-volatile memory 75 as a new second reference waveform (second reference waveform table C2[k]).

[0169] When the number of pulses P input to the stepping motor 66 during the warm-up operation is less than the warm-up number Nw (Y in S920), the electric valve control device 70 repeats the above operation (S830 to S920).

[0170] When the number of pulses P input to the stepping motor 66 during the warm-up operation reaches the warm-up number Nw (N in S920), the electric valve control device 70 sets the one with the larger number of setting times among the first reference waveform and the second reference waveform as the reference waveform (S930). The number of setting times of the first reference waveform is the number of times the actual reciprocal waveform is set as the first reference waveform in steps S740, S790, and S900. The number of setting times of the second reference waveform is the number of times the actual reciprocal waveform is set as the second reference waveform in steps S820 and S910. The electric valve control device 70 ends the warm-up operation and starts the reference setting operation.

[0171] In operation example 2, steps S730, S750, and S830 correspond to the off-time acquisition process, steps S740, S790, S810, S820, S900, S910, and S930 correspond to the reference waveform setting process, and step S630 corresponds to the state determination process.

[0172] 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 stepping motor 66 having a rotor 41 and a stator 60, a valve element 30 facing the valve port 17 and moving toward the valve port 17 when the rotor 41 rotates in a first direction, and a stopper mechanism 49 that restricts the rotation of the rotor 41 in the first direction when the rotor 41 is at a reference position Rx. The stator 60 is connected to H-bridge circuits 77A and 77B which are current circuits for supplying drive current. The H-bridge circuits 77A and 77B have switching elements. The H-bridge circuit 77A operates in a manner that the switching element is turned on when the A-phase current Ia is less than the A-phase current lower limit value Isa, and the switching element is turned off when the A-phase current Ia reaches the A-phase current target value Ita. The H-bridge circuit 77B operates in a manner that the switching element is turned on when the B-phase current Ib is less than the B-phase current lower limit value Isb, and the switching element is turned off when the B-phase current Ib reaches the B-phase current target value Itb.

[0173] The electric valve control device 70 acquires the off-time of the switching elements of the H-bridge circuits 77A and 77B when the A-phase current Ia and the B-phase current Ib for rotating the rotor 41 in the first direction are supplied to the stator 60 (off-time acquisition unit 82). The electric valve control device 70 determines whether the electric valve 5 is in a first rotation restriction state Sr1 based on the off-time (state determination unit 83).

[0174] Due to this, for a normally operable electric valve 5, when the electric valve control device 70 determines that the electric valve 5 is in the first rotation restriction state Sr1, the rotor 41 is at the reference position Rx. Therefore, when the electric valve control device 70 determines that the electric valve 5 is in the first rotation restriction state Sr1, by stopping the rotation of the rotor 41 in the first direction, the time required for the initialization operation can be shortened. Also, after the rotor 41 is positioned at the reference position Rx, the occurrence of noise for a long time can be suppressed.

[0175] Further, the electric valve control device 70 determines whether the electric valve 5 is in the first rotation control state Sr1 based on the OFF times of the switch elements of the H-bridge circuits 77A and 77B. Therefore, components for determining the state of the electric valve 5 based on the rotation of the rotor 41 such as a rotation angle sensor are unnecessary, and the electric valve 5 and the electric valve control device 70 can have a simple configuration.

[0176] Also, for example, when determining the state of the electric valve 5 based on the back electromotive force, since the back electromotive force is obtained when no drive current flows through the stator 60, the timing for obtaining the back electromotive force is limited. On the other hand, when determining the state of the electric valve 5 based on the OFF time, the OFF time can be obtained even when a drive current flows through the stator 60. Therefore, the electric valve control device 70 can timely determine whether the electric valve 5 is in the first rotation control state Sr1.

[0177] Further, the electric valve control device 70 obtains a waveform of the reciprocal of the OFF time (actual reciprocal waveform), and determines whether the electric valve 5 is in the first rotation control state Sr1 based on the degree of difference between the actual reciprocal waveform and a reference waveform of the reciprocal of the OFF time. Therefore, compared with a configuration for determining the state of the electric valve 5 based on the area of the actual reciprocal waveform or the maximum amplitude of the actual reciprocal waveform, the state of the electric valve 5 can be determined with higher accuracy.

[0178] Also, the reference waveform is set based on the actual reciprocal waveform obtained when the A-phase current Ia and the B-phase current Ib for rotating the rotor 41 in the first direction are supplied to the stator 60. Then, the electric valve control device 70 calculates a difference index value sv indicating the degree of difference between the actual reciprocal waveform and the reference waveform, and determines whether the electric valve 5 is in the first rotation control state Sr1 based on the comparison result between the difference index value sv and the difference determination value H. By doing so, the electric valve control device 70 can determine the state of the electric valve 5 with higher accuracy.

[0179] Further, the reference waveform is a data table in which the time t and the reference value rv which is the reciprocal of the off-time at the time t are associated with each other. The electric valve control device 70 calculates an intermediate value dv2 which is a value obtained by squaring the difference value between the reciprocal v of the off-time at the acquisition time tv corresponding to the time t and the reference value rv associated with the time t. The electric valve control device 70 calculates a difference degree index value sv by adding up a plurality of intermediate values dv2. Since it is configured in this way, unlike the area of the waveform and the maximum amplitude of the waveform, the difference degree index value sv appropriately reflects the degree of difference in the shape of the waveform. Therefore, the electric valve control device 70 can determine the state of the electric valve 5 with higher accuracy.

[0180] Note that the difference degree index value sv is not limited to being calculated using the above formula (2). The difference degree index value may be, for example, related to the transition of the magnitude of the reciprocal v at the acquisition time tv. Specifically, the electric valve control device 70 calculates a difference value dv between the reciprocal v of the off-time at the acquisition time tv corresponding to the time t and the reference value rv associated with the time t. The difference value dv is calculated as an absolute value. The electric valve control device 70 uses the number of those having a value equal to or greater than a predetermined difference determination value among the plurality of difference values dv calculated for the energization period D as the difference degree index value. Such a difference degree index value also appropriately reflects the degree of difference in the shape of the waveform.

[0181] Also, the electric valve control device 70 inputs a pulse P to the stepping motor 66 to rotate the rotor 41 (rotation control unit 81). The electric valve control device 70 sets a reference waveform (reference waveform setting unit 84). The H-bridge circuits 77A and 77B supply a phase A current Ia and a phase B current Ib corresponding to the pulse P to the stator 60 in response to the input of the pulse P to the stepping motor 66. The electric valve control device 70 performs a preparation operation of inputting a pulse P of a preparation number Np to the stepping motor 66 to rotate the rotor 41 in the second direction. Subsequently to the preparation operation, the electric valve control device 70 performs a warm-up operation of inputting a pulse P of a warm-up number Nw to the stepping motor 66 to rotate the rotor 41 in the first direction. The warm-up number Nw is the same as the preparation number Np. The electric valve control device 70 sets the actual reciprocal waveform acquired during the warm-up operation as the reference waveform. By doing so, the electric valve control device 70 sets the actual reciprocal waveform acquired at a time point after a certain period has elapsed since the electric valve 5 started operating as the reference waveform. Therefore, a relatively stable actual reciprocal waveform actually acquired using the electric valve 5 can be used as the reference waveform, and the state of the electric valve 5 can be determined with higher accuracy.

[0182] Also, when the electric valve control device 70 starts the warm-up operation in operation example 1, the reference waveform is not set. The electric valve control device 70 performs a determination operation of determining whether the actual reciprocal waveform and the reference waveform are similar based on the degree of difference between the actual reciprocal waveform acquired during the warm-up operation and the reference waveform. After the electric valve control device 70 sets the reference waveform, it starts the determination operation. When the number of pulses P input to the stepping motor 66 in the warm-up operation reaches K, the electric valve control device 70 sets the actual reciprocal waveform acquired as the reference waveform. When the electric valve control device 70 determines in the determination operation that the actual reciprocal waveform and the reference waveform are similar, it sets the actual reciprocal waveform related to the determination as the reference waveform. When the electric valve control device 70 determines in the determination operation that the actual reciprocal waveform and the reference waveform are not similar, it maintains the reference waveform. By doing so, the electric valve control device 70 can set a reference waveform suitable for the electric valve 5.

[0183] Further, in the determination operation, the electric valve control device 70 calculates a difference index value sv indicating the degree of difference between the actual reciprocal waveform and the reference waveform, and determines whether the actual reciprocal waveform and the reference waveform are similar based on the comparison result between the difference index value sv and the similarity determination value G. By doing so, the electric valve control device 70 can set a reference waveform more suitable for the electric valve 5.

[0184] Also, when the electric valve control device 70 starts the warm-up operation in operation example 2, the first reference waveform and the second reference waveform are not set. The electric valve control device 70 performs a first determination operation to determine whether the actual reciprocal waveform and the first reference waveform are similar based on the degree of difference between the actual reciprocal waveform acquired during the warm-up operation and the first reference waveform. The electric valve control device 70 performs a second determination operation to determine whether the actual reciprocal waveform and the second reference waveform are similar based on the degree of difference between the actual reciprocal waveform acquired during the warm-up operation and the second reference waveform. After the electric valve control device 70 sets the first reference waveform, it starts the first determination operation. After the electric valve control device 70 sets the second reference waveform, it starts the second determination operation. When the number of pulses P input to the stepping motor 66 in the warm-up operation reaches K in the electric valve control device 70, the electric valve control device 70 sets the actual reciprocal waveform it has acquired as the first reference waveform. When the electric valve control device 70 determines in the first determination operation that the actual reciprocal waveform and the first reference waveform are similar, it sets the actual reciprocal waveform related to the determination as the first reference waveform. When the electric valve control device 70 determines in the first determination operation that the actual reciprocal waveform and the first reference waveform are not similar, it maintains the first reference waveform. When the electric valve control device 70 first determines in the first determination operation that the actual reciprocal waveform and the first reference waveform are not similar, it sets the actual reciprocal waveform related to the determination as the second reference waveform. When the electric valve control device 70 determines in the second determination operation that the actual reciprocal waveform and the second reference waveform are similar, it sets the actual reciprocal waveform related to the determination as the second reference waveform. When the electric valve control device 70 determines in the second determination operation that the actual reciprocal waveform and the second reference waveform are not similar, it maintains the second reference waveform. Before the warm-up operation ends, the electric valve control device 70 sets the one with the larger number of setting times among the first reference waveform and the second reference waveform as the reference waveform. By doing so, the electric valve control device 70 can set a reference waveform suitable for the electric valve 5.

[0185] Also, when the electric valve control device 70 determines that the actual reciprocal waveform is similar to the first reference waveform in the first determination operation and determines that the actual reciprocal waveform is similar to the second reference waveform in the second determination operation, the actual reciprocal waveform related to the determination is set as the one that is more similar to the actual reciprocal waveform among the first reference waveform and the second reference waveform. By doing so, it is possible to avoid the situation where one actual reciprocal waveform is set as both the first reference waveform and the second reference waveform.

[0186] Also, the electric valve control device 70 calculates a first difference index value sv1 indicating the degree of difference between the actual reciprocal waveform and the first reference waveform in the first determination operation, and determines whether the actual reciprocal waveform is similar to the first reference waveform based on the comparison result between the first difference index value sv1 and the similarity determination value G. In the second determination operation, the electric valve control device 70 calculates a second difference index value sv2 indicating the degree of difference between the actual reciprocal waveform and the second reference waveform, and determines whether the actual reciprocal waveform is similar to the second reference waveform based on the comparison result between the second difference index value sv2 and the similarity determination value G. By doing so, the electric valve control device 70 can set the first reference waveform, the second reference waveform, and the reference waveform that are more suitable for the electric valve 5.

[0187] Also, the electric valve control device 70 may perform the preparation operation and the warm-up operation multiple times, and set the actual reciprocal waveform obtained during the last warm-up operation as the reference waveform. By doing so, the electric valve 5 can be sufficiently warmed up, and a more stable actual reciprocal waveform can be set as the reference waveform.

[0188] Further, after the warm-up operation, the electric valve control device 70 performs a reference setting operation of inputting a pulse P to the stepping motor 66 to rotate the rotor 41 in the first direction. When the electric valve control device 70 determines that the electric valve 5 is in the first rotation restriction state Sr1 during the reference setting operation, the input of the pulse P to the stepping motor 66 is stopped. When the number of pulses P input to the stepping motor 66 in the warm-up operation and the reference setting operation exceeds the initialization number Ni, the electric valve control device 70 determines that the electric valve 5 is malfunctioning. By doing so, for example, compared to a configuration in which the air conditioner control device 110 is notified that the electric valve 5 is in the first rotation restriction state Sr1, receives a stop command from the air conditioner control device 110, and stops the initialization operation, the electric valve control device 70 can simply and quickly stop the rotation of the rotor 41 in the first direction. Further, the electric valve control device 70 can detect that the electric valve 5 has malfunctioned.

[0189] The electric valve control device 70 sets the actual reciprocal waveform acquired in the initialization operation as the reference waveform. For example, the electric valve control device 70 may have a configuration in which the actual reciprocal waveform acquired at the time of factory shipment using the electric valve 5 is set in advance as the reference waveform. The electric valve control device 70 having this configuration starts inputting pulses P to the stepping motor 66 in ascending order without performing the preparation operation and the warm-up operation in the initialization operation, and performs the reference setting operation.

[0190] 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 that term. For example, a "cylindrical member" includes a cylindrical member and a member that is substantially cylindrical. Further, in this specification, the term "the same" may include cases where they are exactly the same and cases where they are substantially the same.

[0191] 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.

Description of Reference Numerals

[0192] 1… Electric valve device, 5… Electric valve, 10… Valve body, 11… Body member, 11a… Fitting hole, 11b… Through hole, 11d… Plane, 13… Connecting member, 14… Valve chamber, 15… First conduit, 16… Second conduit, 17… Valve port, 18… Valve seat, 20… Cam, 30… Valve element, 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, 43d… Plane, 44… Stopper member, 44a… Stopper body, 44c… Female thread, 44s… Fixed stopper, 45… Fixture, 45a… Fixing portion, 45b… Flange portion, 46… Washer, 47… Closing spring, 48… Return spring, 49… Stopper mechanism, 60… Stator, 61… A-phase stator, 61a… Pole teeth, 61b… Pole teeth, 61c… A-phase coil, 62… B-phase stator, 62a… Pole teeth, 62b… Pole teeth, 62c… B-phase coil, 66… Stepping motor, 70… 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, 80… Computer, 81… Rotation control unit, 82… Off-time acquisition unit, 83… State determination unit, 84… Reference waveform setting unit, 100… Air conditioning system, 101… Compressor, 102… Condenser, 103… Evaporator, 105… Pipe, 110… Air conditioning control device, 120… Wired communication bus, L… Axis

Claims

1. A valve body having a valve port, a stepping motor having a rotor and a stator, a valve element facing the valve port and moving toward the valve port when the rotor rotates in a first direction, and a stopper mechanism that restricts the rotation of the rotor in the first direction when the rotor is in a reference position. An electric valve control device for controlling an electric valve, wherein the stator is connected to a current circuit that supplies a drive current, the current circuit has a switching element, and the switching element is turned on when the drive current is less than a lower limit value that is smaller than a target value by a fixed value, and the switching element is turned off when the drive current reaches the target value, and operates in such a manner, the electric valve control device, an off-time acquisition unit that acquires the off-time of the switching element when the drive current for rotating the rotor in the first direction is supplied to the stator, and a state determination unit that determines whether or not the electric valve is in a first rotation restriction state in which the rotation of the rotor in the first direction is restricted based on the off-time. An electric valve control device characterized by comprising.

2. The state determination unit determines whether or not the electric valve is in the first rotation restriction state based on the degree of difference between the waveform of the reciprocal of the off-time acquired by the off-time acquisition unit and the reference waveform of the reciprocal of the off-time. The electric valve control device according to claim 1.

3. The reference waveform is set based on the waveform of the reciprocal of the off-time acquired when the drive current for rotating the rotor in the first direction is supplied to the stator, the state determination unit calculates a difference index value indicating the degree of difference between the waveform of the reciprocal of the off-time acquired by the off-time acquisition unit and the reference waveform, and based on the comparison result between the difference index value and the difference determination value, determines whether or not the electric valve is in the first rotation restriction state. The electric valve control device according to claim 2.

4. The reference waveform is a data table in which a time and a reference value of the reciprocal of the off-time at that time are associated, the state determination unit calculates an intermediate value that is a value obtained by squaring a difference value between the reciprocal of the off-time acquired by the off-time acquisition unit at the acquisition time corresponding to the time and the reference value associated with the time, and the state determination unit calculates the difference index value by adding up a plurality of the intermediate values. The electric valve control device according to claim 3.

5. The electric valve control device, a rotation control unit that inputs pulses to the stepping motor to rotate the rotor, and a reference waveform setting unit that sets the reference waveform, further includes, the current circuit supplies the driving current corresponding to the pulse to the stator in response to the input of the pulse to the stepping motor, the rotation control unit performs a preparation operation of inputting a preparation number of pulses to the stepping motor to rotate the rotor in the second direction, and following the preparation operation, performs a warm-up operation of inputting a warm-up number of pulses less than or equal to the preparation number to the stepping motor to rotate the rotor in the first direction, the reference waveform setting unit sets, as the reference waveform, a waveform that is the reciprocal of the off-time acquired by the off-time acquisition unit during the warm-up operation. The electric valve control device according to claim 2.

6. An electric valve device including the electric valve and the electric valve control device according to claim 1.

7. A control method for an electric valve, comprising a valve body having a valve port, a stepping motor having a rotor and a stator, a valve body facing the valve port and moving toward the valve port when the rotor rotates in a first direction, and a stopper mechanism that restricts the rotation of the rotor in the first direction when the rotor is in a reference position, the stator is connected to a current circuit that supplies a driving current, the current circuit has a switching element, and operates in such a manner that the switching element is turned on when the driving current is less than a lower limit value that is smaller than a target value by a fixed value, and the switching element is turned off when the driving current reaches the target value, the control method includes, an off-time acquisition step of acquiring an off-time of the switching element when the driving current for rotating the rotor in the first direction is supplied to the stator, and a state determination step of determining, based on the off-time, whether or not the electric valve is in a first rotation restriction state in which the rotation of the rotor in the first direction is restricted. The control method for an electric valve is characterized by including the above steps.

Images