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

Abstract

Provided is an electric valve control device, electric valve device, and control method for an electric valve that can suppress misalignment of a stepping motor and deterioration of durability of an electric valve. The electric valve (5) has a rotor (41) and a stator (60) connected to a motor driver. A computer of the electric valve control device (70) rotates the rotor (41) by supplying driving current corresponding to a plurality of pulses to the stator (60) by inputting the plurality of pulses to the motor driver. The computer makes the driving current corresponding to the last at least one pulse larger than the driving current corresponding to the pulse before the last at least one pulse.

Description

Technical Field

[0001] This invention relates to an electric valve control device, an electric valve device having an electric valve control device, and a method for controlling an electric valve. Background Technology

[0002] Patent Document 1 discloses a conventional electric valve. The electric valve in Patent Document 1 includes a stepper motor, a reduction gear mechanism, a drive shaft, a bearing assembly, and a valve core. The stepper motor has a rotor and a stator connected to a motor driver. When a pulse is input to the stepper motor, the rotor rotates. Specifically, when a drive current corresponding to the pulse is supplied to the stator by inputting a pulse to the motor driver, the rotor rotates. The rotation of the rotor is transmitted to the drive shaft via the reduction gear mechanism. The drive shaft has an external thread. The bearing assembly has an internal thread that engages with the external thread. When the drive shaft rotates, the drive shaft moves axially. The valve core moves axially along with the movement of the drive shaft.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2012-197849.

[0006] The technical problem that the invention aims to solve

[0007] When pulses are input to the stepper motor, the rotor rotates; when the pulse input stops, the rotor stops. However, sometimes the rotor doesn't stop immediately after the pulse input stops, resulting in excessive rotation. This causes stepper motor misalignment. While continuously supplying a relatively large drive current corresponding to the pulsations to the stator can suppress excessive rotor rotation, it can sometimes exacerbate wear on components such as gears and drive shafts in the reduction mechanism. Consequently, the durability of the electric valve decreases. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide an electric valve control device, an electric valve device, and an electric valve control method that can suppress stepper motor misalignment and the decrease in the durability of electric valves.

[0009] Technical methods for solving technical problems

[0010] The inventors conducted in-depth research on the misalignment of stepper motors using multiple electric valves. As a result, the inventors discovered the following (i) to (iii), thereby achieving the present invention.

[0011] (i) When multiple pulses are input to the stepper motor, or when the input speed of the pulses increases when multiple pulses are input, the angular velocity of the rotor increases toward the peak value corresponding to the input speed of the pulses.

[0012] (ii) If the rotor's angular velocity does not reach its peak value before the last pulse of the input pulse, stepper motor misalignment is likely to occur; if the rotor's angular velocity reaches its peak value before the last pulse of the input pulse, stepper motor misalignment is unlikely to occur.

[0013] (iii) If the drive current supplied to the stator is relatively large, it is difficult to cause stepper motor misalignment.

[0014] To achieve the above objectives, one aspect of the present invention relates to an electric valve control device that controls an electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator connected to a motor driver; and a valve core that moves relative to the valve port when the rotor rotates. The electric valve control device is characterized in that it has a processing unit that supplies a drive current corresponding to the plurality of pulses to the stator to rotate the rotor by inputting a plurality of pulses to the motor driver, wherein the processing unit makes the drive current corresponding to the last at least one of the plurality of pulses greater than the drive current corresponding to the pulses preceding the last at least one pulse.

[0015] To achieve the above objectives, another aspect of the present invention relates to an electric valve control device that controls an electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator connected to a motor driver; and a valve core that moves relative to the valve port when the rotor rotates. The electric valve control device is characterized in that it has a processing unit that supplies a drive current corresponding to the plurality of pulses to the stator to rotate the rotor by inputting a plurality of pulses to the motor driver. The processing unit ensures that the drive current corresponding to at least the last pulse among the plurality of pulses is greater than the drive current corresponding to pulses preceding the last at least one pulse. "At least the last pulse among the plurality of pulses" also includes either the last pulse among the plurality of pulses or a series of consecutive pulses including the last pulse among the plurality of pulses.

[0016] In this invention, preferably, the processing device inputs the plurality of pulses to the motor driver at a predetermined input speed. When it is determined that the rotor's angular velocity has not reached the peak value corresponding to the predetermined input speed before the last pulse is input, the processing device makes the drive current (second drive current) corresponding to the last at least one pulse larger than the drive current (first drive current) corresponding to the pulses before the last at least one pulse. When it is determined that the rotor's angular velocity has reached the peak value before the last pulse is input, the processing device keeps the magnitude of the drive current (first drive current) corresponding to the plurality of pulses constant.

[0017] In this invention, preferably, when the number of pulses input to the motor driver to rotate the rotor from the current position to the target position is set to M, the number of pulses required for the rotor's angular velocity to reach the peak value from 0 when pulses are input to the motor driver at the predetermined input speed is set to N, and a natural number greater than 1 and less than N is set to S, when the processing device rotates the rotor from the current position to the target position, M is obtained. When M > N, the processing device supplies the stator with M pulses corresponding to the M pulses by inputting M pulses to the motor driver at the predetermined input speed. When M≤N and M>S, the processing device supplies the stator with a first driving current corresponding to (M-S) pulses by inputting (M-S) pulses to the motor driver at the predetermined input speed. Then, it supplies the stator with a second driving current greater than the first driving current corresponding to the S pulses by inputting S pulses to the motor driver at the predetermined input speed. When M≤S, the processing device supplies the stator with a second driving current corresponding to the M pulses by inputting M pulses to the motor driver at the predetermined input speed.

[0018] In this invention, preferably, when the number of pulses input to the motor driver to rotate the rotor from the current position to the target position is set to M, and the number of pulses required for the rotor's angular velocity to reach the peak value from 0 when pulses are input to the motor driver at the predetermined input speed is set to N, the processing device obtains M when rotating the rotor from the current position to the target position. When M > N, the processing device supplies the stator with a first driving current corresponding to M pulses by inputting M pulses to the motor driver at the predetermined input speed. When M ≤ N, the processing device supplies the stator with a second driving current greater than the first driving current corresponding to M pulses by inputting M pulses to the motor driver at the predetermined input speed.

[0019] In this invention, preferably, the number of pulses required for the rotor's angular velocity to reach the peak value from 0 is set based on the back electromotive force generated in the stator when the rotor rotates by supplying the first driving current corresponding to the pulse to the stator.

[0020] In this invention, preferably, the first driving current is a current that alternately changes to a first current value and a second current value, and the number of pulses required for the rotor's angular velocity to reach the peak value is set based on the time it takes for the first driving current flowing through the stator to change from the first current value to the second current value when the rotor rotates by supplying the first driving current to the stator.

[0021] In this invention, preferably, the drive current includes a first drive current and a second drive current larger than the first drive current. The first drive current is a current that alternately changes between a first current value and a second current value. When the number of pulses input to the motor driver to rotate the rotor from the current position to the target position is set to M, when the processing device rotates the rotor from the current position to the target position, M is obtained. The processing device supplies the stator with the first drive current corresponding to the (M-1) pulses by inputting (M-1) pulses to the motor driver at the predetermined input speed. The processing device is based on the (M-1)th pulse flowing through the stator... -1) The processing device determines whether the rotor's angular velocity reaches the peak value before the Mth pulse is input. When it is determined that the rotor's angular velocity has reached the peak value, the processing device inputs the Mth pulse to the motor driver at the predetermined input speed, thereby supplying the stator with the first drive current corresponding to the Mth pulse. When it is determined that the rotor's angular velocity has not reached the peak value, the processing device inputs the Mth pulse to the motor driver at the predetermined input speed, thereby supplying the stator with the second drive current corresponding to the Mth pulse.

[0022] To achieve the above objectives, another aspect of the present invention relates to an electric valve device having the electric valve and the electric valve control device.

[0023] To achieve the above objectives, another aspect of the present invention relates to a control method for an electric valve, the electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator connected to a motor driver; and a valve core that moves relative to the valve port when the rotor rotates. The control method for the electric valve is characterized in that, by inputting a plurality of pulses to the motor driver, a drive current corresponding to the plurality of pulses is supplied to the stator to rotate the rotor, such that the drive current corresponding to the last pulse among the plurality of pulses is greater than the drive current corresponding to the pulses preceding the last pulse.

[0024] To achieve the above objectives, another aspect of the present invention relates to a control method for an electric valve, the electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator connected to a motor driver; and a valve core that moves relative to the valve port when the rotor rotates. The control method is characterized in that the rotor is rotated by supplying a drive current corresponding to the plurality of pulses to the stator by inputting a plurality of pulses to the motor driver, such that the drive current corresponding to the last at least one of the plurality of pulses is greater than the drive current corresponding to the pulses preceding the last at least one pulse.

[0025] In this invention, preferably, the plurality of pulses are input to the motor driver at a predetermined input speed. When it is determined that the rotor angular velocity has not reached the peak value corresponding to the predetermined input speed before the last pulse is input, the drive current corresponding to the last at least one pulse is made larger than the drive current corresponding to the pulses before the last at least one pulse. When it is determined that the rotor angular velocity has reached the peak value before the last pulse is input, the magnitude of the drive current corresponding to the plurality of pulses is kept constant.

[0026] The effects of the invention

[0027] According to the present invention, the rotor is rotated by supplying a drive current corresponding to the multiple pulses to the stator through inputting multiple pulses to the motor driver. Furthermore, the drive current corresponding to the last at least one of the multiple pulses is made larger than the drive current corresponding to the pulses preceding the last at least one pulse. Therefore, when the last at least one pulse is input, the stator pole teeth strongly attract the rotor's magnetic poles. Thus, by not consistently supplying a relatively large drive current to the stator, excessive rotor rotation can be suppressed. Therefore, stepper motor misalignment and decreased durability of the electric valve can be suppressed. Attached Figure Description

[0028] Figure 1 This is a block diagram of an air conditioner equipped with an electric valve.

[0029] Figure 2 This is a cross-sectional view of an electric valve device.

[0030] Figure 3 This is a schematic diagram showing the rotor and stator of the stepper motor in an electric valve device.

[0031] Figure 4 This is a schematic diagram illustrating the computer and motor driver of an electric valve control device that includes a stepper motor and an electric valve assembly.

[0032] Figure 5 This is a diagram illustrating an example of the relationship between a pulse and the stepping and direction signals input to the motor driver.

[0033] Figure 6 This is a diagram illustrating an example of the correspondence between a pulse and the currents in phases A and B.

[0034] Figure 7 This is a graph that schematically illustrates an example of the relationship between the number of pulse inputs and the angular velocity of the rotor.

[0035] Figure 8 This is a graph illustrating an example of the relationship between the number of pulse inputs and the angular velocity of the rotor.

[0036] Figure 9 It is a diagram that schematically represents the waveform of the driving current flowing through the coils of the stator.

[0037] Figure 10 This is a flowchart illustrating the first action of an electric valve control device.

[0038] Figure 11 This is a flowchart illustrating the second action example of an electric valve control device.

[0039] Figure 12 This is a flowchart illustrating the third action example of an electric valve control device.

[0040] Figure 13 This is a flowchart illustrating the fourth action of the electric valve control device. Detailed Implementation

[0041] The electric valve device according to an embodiment of the present invention will be described below.

[0042] The electric valve device 1 involved in this embodiment is, for example, assembled in the refrigeration cycle system of the air conditioner 100 and used as a flow control valve to control the flow rate of the refrigerant. The electric valve device 1 includes an electric valve 5 and an electric valve control device 70. Figure 1 A block diagram showing an air conditioner 100 having an electric valve device 1. Figure 2 This is a cross-sectional view of the electric valve device 1.

[0043] Air conditioner 100 includes a compressor 101, a condenser 102, an electric valve device 1 (electric valve 5), and an evaporator 103, which are connected in sequence via piping 105. The electric valve device 1 is an expansion valve. Air conditioner 100 includes an air conditioning control unit 110. The air conditioning control unit 110 is communicatively connected to the electric valve device 1 (electric valve control unit 70). The air conditioning control unit 110 uses the electric valve device 1 to control the flow rate of refrigerant flowing in piping 105.

[0044] The electric valve 5 has a valve body 10, a valve core 20, a drive mechanism 30, and a stator 60.

[0045] The valve body 10 has a housing 11, a sleeve 14, a connecting plate 15, and an outer shell 18.

[0046] The housing 11 has a bottomed cylindrical shape. The housing 11 has a valve chamber 12 and a valve port 13 connected to the valve chamber 12. A first conduit 16 is joined to the peripheral wall portion 11a of the housing 11. The first conduit 16 is connected to the valve chamber 12. A second conduit 17 is joined to the bottom wall portion 11b of the housing 11. The second conduit 17 is connected to the valve port 13 located in the bottom wall portion 11b. An upward-facing annular plane 11c is provided on the inner peripheral surface of the peripheral wall portion 11a.

[0047] The sleeve 14 has a cylindrical shape. The sleeve 14 integrally has a cylindrical portion 14a and a flange portion 14b. The inner diameter of the upper part of the cylindrical portion 14a is larger than the inner diameter of the lower part of the cylindrical portion 14a. The flange portion 14b has an annular shape. The inner periphery of the flange portion 14b is connected to the upper end of the cylindrical portion 14a. The flange portion 14b is in contact with the annular plane 11c of the housing 11. An upward-facing annular plane 14c is provided on the inner peripheral surface of the cylindrical portion 14a.

[0048] The connecting plate 15 has an annular shape. A peripheral wall portion 11a is disposed on the inner side of the connecting plate 15. The inner periphery of the connecting plate 15 engages with the peripheral wall portion 11a.

[0049] The outer casing 18 has a cylindrical shape. The lower end of the outer casing 18 is open and the upper end is closed. The lower end of the outer casing 18 engages with the outer periphery of the connecting plate 15.

[0050] The valve core 20 has a body 21, a valve portion 22, a spring support portion 23, and a ball support portion 24. The body 21 is cylindrical. The valve portion 22 is conical with its apex pointing downwards. The valve portion 22 is coaxially connected to the lower end of the body 21. The valve portion 22 and the valve port 13 are opposite each other in the vertical direction (axis L direction). The spring support portion 23 is annular. The outer diameter of the spring support portion 23 is larger than the outer diameter of the body 21. The inner periphery of the spring support portion 23 is connected to the upper end of the body 21. The body 21, valve portion 22, and spring support portion 23 are integrally formed. The ball support portion 24 is mounted on the upper end face of the body 21.

[0051] The body 21 is disposed inside the cylindrical portion 14a of the sleeve 14 and is supported by the lower part of the cylindrical portion 14a so that it can move in the vertical direction. The valve opening spring 25 is disposed between the spring support portion 23 and the annular plane 14c of the sleeve 14. The valve opening spring 25 is a compression helical spring that presses the valve core 20 upward.

[0052] The drive mechanism 30 moves the valve core 20 in the vertical direction. The drive mechanism 30 is located inside the housing 18. The drive mechanism 30 includes a drive shaft 31, a bearing component 35, a rotor 41, a connecting component 42, a rotor shaft 43, a support component 44, and a planetary gear mechanism 50.

[0053] The drive shaft 31 has a cylindrical portion 32, a flat portion 33, and a ball 34. The cylindrical portion 32 has an external thread 32t. The external thread 32t is disposed on the outer peripheral surface of the cylindrical portion 32. The flat portion 33 extends upward from the upper end surface of the cylindrical portion 32. The cylindrical portion 32 and the flat portion 33 are integrally formed. The ball 34 engages with the lower end surface of the cylindrical portion 32. The drive shaft 31 is connected to the valve core 20. Specifically, the ball 34 of the drive shaft 31 is slidably connected to the ball support portion 24 of the valve core 20.

[0054] The bearing component 35 has a cylindrical shape. The bearing component 35 is disposed on the inner side of the upper part of the peripheral wall portion 11a of the housing 11. The bearing component 35 is fixed to the peripheral wall portion 11a. A flange portion 14b of the sleeve 14 is maintained between the lower end face of the bearing component 35 and the annular plane 11c of the peripheral wall portion 11a. The bearing component 35 has an internal thread 35t. The internal thread 35t is disposed on the lower part of the inner peripheral surface of the bearing component 35. The external thread 32t of the drive shaft 31 engages with the internal thread 35t.

[0055] Rotor 41 has a cylindrical shape. Rotor 41 is rotatable relative to valve body 10. Rotor 41 has multiple magnetic poles (multiple N poles and multiple S poles). The multiple N poles and multiple S poles are arranged on the outer circumferential surface of rotor 41. The multiple N poles and multiple S poles extend in the vertical direction. The multiple N poles and multiple S poles are arranged alternately at equal angular intervals in the circumferential direction. Rotor 41, for example, has 12 N poles and 12 S poles. The position (angle) of rotor 41 is related to the opening degree of valve port 13. Figure 3 The rotor 41 and stator 60 are schematically represented in the diagram. Figure 3 In the diagram, the outer radial side of the stator 60 corresponds to the top of the stator 60, and the inner radial side corresponds to the bottom.

[0056] The connecting member 42 has a circular plate shape. The connecting member 42 connects the upper end of the rotor 41 and the rotor shaft 43. The connecting member 42 rotates together with the rotor 41. The support member 44 is disposed above the rotor 41. The support member 44 supports the upper end of the rotor shaft 43 so that it can rotate.

[0057] The planetary gear mechanism 50 is a speed reduction mechanism that slows down the rotation of the rotor 41. The planetary gear mechanism 50 connects the rotor 41 and the drive shaft 31, and transmits the rotation of the rotor 41 to the drive shaft 31. The planetary gear mechanism 50 is located inside the rotor 41. The planetary gear mechanism 50 includes a gearbox 51, a fixed ring gear 52, a sun gear 53, multiple planetary gears 54, a planetary gear carrier 55, an output gear 56, and an output shaft 57.

[0058] Gearbox 51 has a cylindrical shape. Gearbox 51 is fixed to the upper part of the peripheral wall 11a of housing 11. Fixed gear ring 52 is an internal gear. Fixed gear ring 52 is fixed to the upper part of gearbox 51. Sun gear 53 is connected to the lower surface of connecting member 42. Sun gear 53 and connecting member 42 are integrally formed. Rotor shaft 43 is inserted through the inside of sun gear 53. Multiple planet gears 54 surround sun gear 53. Multiple planet gears 54 mesh with fixed gear ring 52 and sun gear 53. Planet gear carrier 55 has a plate shape. Planet gear carrier 55 has a support shaft that supports multiple planet gears 54 for rotation. Output gear 56 is an internal gear with a bottom cylindrical shape. Output gear 56 meshes with multiple planet gears 54.

[0059] The output shaft 57 is cylindrical. The lower part of the output shaft 57 is disposed inside the bearing component 35. The output shaft 57 is rotatably supported on the bearing component 35. The upper part of the output shaft 57 is fixed to the bottom of the output gear 56. The output shaft 57 rotates together with the output gear 56. The output shaft 57 has a bearing bore for the lower end of the rotor shaft 43. The output shaft 57 supports the lower end of the rotor shaft 43 so that it is rotatable.

[0060] The output shaft 57 has a slit 57a extending in the vertical direction. The slit 57a is disposed at the lower part of the output shaft 57. The width of the slit 57a is the same as the thickness of the flat plate portion 33 of the drive shaft 31. The output shaft 57 is connected to the drive shaft 31. Specifically, the flat plate portion 33 is disposed in the slit 57a in a manner that allows it to move in the vertical direction. When the output shaft 57 rotates, the flat plate portion 33 (drive shaft 31) rotates, and the flat plate portion 33 moves in the vertical direction within the slit 57a.

[0061] The stator 60 has a cylindrical shape. The stator 60 has an A-phase stack 61 and a B-phase stack 62.

[0062] The A-phase stack 61 has a plurality of claw-shaped pole teeth 61a and 61b. The tips of pole teeth 61a face downwards, and the tips of pole teeth 61b face upwards. The pole teeth 61a and 61b are arranged alternately at equal angular intervals in the circumferential direction. The A-phase stack 61 has, for example, 12 pole teeth 61a and 12 pole teeth 61b. The A-phase stack 61 has an A-phase coil 61c. When the A-phase coil 61c is energized, the pole teeth 61a and 61b become magnetic poles of opposite polarities.

[0063] The B-phase stack 62 has multiple claw-shaped pole teeth 62a and 62b. The tips of pole teeth 62a face downwards, and the tips of pole teeth 62b face upwards. The pole teeth 62a and 62b are arranged alternately at equal angular intervals in the circumferential direction. The B-phase stack 62 has, for example, 12 pole teeth 62a and 12 pole teeth 62b. The B-phase stack 62 has a B-phase coil 62c. When the B-phase coil 62c is energized, the pole teeth 62a and 62b become magnetic poles of opposite polarity. The B-phase stack 62 has the same structure as the A-phase stack 61.

[0064] Phase A stack 61 is disposed on top of phase B stack 62. Phase B stack 62 is located at a position that is rotated by an angle α relative to phase A stack 61 about axis L, from the position where pole teeth 61a and 62a are arranged along axis L. Angle α is half the angle between pole teeth 61a and 61b. The pole teeth 61a and 61b of phase A stack 61 and the pole teeth 62a and 62b of phase B stack 62 form the inner circumferential surface of stator 60.

[0065] A housing 18 is disposed inside the stator 60. A rotor 41 is disposed inside the housing 18. The magnetic poles of the rotor 41 are radially opposite to the pole teeth 61a, 61b, 62a, 62b of the stator 60, separated by the housing 18. The stator 60 and rotor 41 are stepper motors 66. The stepper motor 66 is controlled by an electric valve control device 70. Furthermore, the structure of the stepper motor 66 described above (e.g., the number of magnetic poles of the rotor 41, the number of pole teeth of the stator 60) is an example and can be changed according to the application of the electric valve device 1, etc.

[0066] In this embodiment, the stepper motor 66 is controlled in a two-phase excitation mode. The rotor 41 rotates by inputting pulses P (P[1]~P[4]) to the stepper motor 66. Specifically, a motor driver 77 of an electric valve control device 70 is connected to the stator 60 of the stepper motor 66. By inputting pulses P to the motor driver 77, a drive current corresponding to pulse P is supplied to the stator 60, thereby causing the rotor 41 to rotate. In this specification, "inputting pulses P to the stepper motor 66" and "supplying a drive current corresponding to pulse P to the stator 60 by inputting pulses P to the motor driver 77" are synonymous. In addition, the stepper motor 66 can also be controlled in a one-phase excitation mode, a one-two-phase excitation mode, a W1-two-phase excitation mode, a two-W1-two-phase excitation mode, or a four-W1-two-phase excitation mode.

[0067] When pulse P is input to stepper motor 66 in ascending order (pulse P[1]~P[4] in sequence), rotor 41 moves in the first direction ( Figure 3 The rotor 41 rotates clockwise. The rotation of the rotor 41 is transmitted to the drive shaft 31 via the planetary gear mechanism 50. When the drive shaft 31 rotates, it moves downwards through a threaded feed action. The drive shaft 31 presses the valve core 20 downwards. As the valve core 20 moves downwards, the valve portion 22 approaches the valve port 13, and the opening of the valve port 13 decreases. When the valve portion 22 contacts the periphery (valve seat) of the valve port 13, the opening of the valve port 13 becomes minimal (zero). Even when the opening of the valve port 13 is minimal, a gap can still be formed between the valve portion 22 and the valve seat.

[0068] When pulse P is input to stepper motor 66 in descending order (pulse P[4]~P[1] in sequence), rotor 41 moves in the second direction ( Figure 3 The rotor 41 rotates counterclockwise. The rotation of the rotor 41 is transmitted to the drive shaft 31 via the planetary gear mechanism 50. When the drive shaft 31 rotates, it moves upwards through the threaded feed action. The valve core 20, pressed against the valve opening spring 25, moves upwards, the valve part 22 moves away from the valve port 13, and the opening degree of the valve port 13 increases. When the valve part 22 is furthest away from the valve port 13, the opening degree of the valve port 13 reaches its maximum.

[0069] The central axis of each of the following components is aligned with axis L: housing 11, valve port 13, sleeve 14, outer shell 18, valve core 20, drive shaft 31, bearing component 35, rotor 41, connecting component 42, rotor shaft 43, fixed gear ring 52, sun gear 53, output gear 56, output shaft 57, and stator 60 (A phase stack 61, B phase stack 62).

[0070] The electric valve control device 70 has a baseboard 71 on which multiple electronic components (not shown) are mounted. The electric valve control device 70 includes 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 commands received from the air conditioning control device 110.

[0071] Non-volatile memory 75 stores data that needs to be retained even when the power is cut off. Non-volatile memory 75 is, for example, EEPROM or flash memory. Non-volatile memory 75 is a storage unit.

[0072] The communication device 76 is connected to the air conditioning control device 110 via a wired communication bus 120 in a communicative manner. The air conditioner 100 may use communication methods such as Local Interconnect Network (LIN) or Controller Area Network (CAN). Alternatively, the communication device 76 may also be connected to the air conditioning control device 110 in a wireless communication manner.

[0073] The motor driver 77 is controlled by the computer 80. The motor driver 77 supplies drive current to the stator 60 to rotate the rotor 41. For example... Figure 4 As shown, the motor driver 77 is connected to terminals A1 and A2 of phase A coil 61c and terminals B1 and B2 of phase B coil 62c. The motor driver 77 supplies phase A current to phase A coil 61c and phase B current to phase B coil 62c. The motor driver 77 can also be installed in the electric valve 5.

[0074] Computer 80 inputs a step signal (STEP) and a direction signal (DIR) to motor driver 77. The step signal is a pulse signal. When a direction signal corresponding to the first direction (e.g., an H-level signal) is input to motor driver 77, the step signal is input, which is equivalent to pulses P being input to stepper motor 66 in ascending order. When a direction signal corresponding to the second direction (e.g., an L-level signal) is input to motor driver 77, the step signal is input, which is equivalent to pulses P being input to stepper motor 66 in descending order. Figure 5 This is an example illustrating the relationship between the pulse P input to the stepper motor 66 and the stepping signal and direction signal input to the motor driver 77.

[0075] Additionally, a current control signal (CTRL) is input from the computer 80 to the motor driver 77. The current control signal is used to set the magnitude of the drive current in the motor driver 77.

[0076] Figure 6 This example illustrates the correspondence between pulse P and the drive current (phase A current, phase B current) supplied by motor driver 77. Figure 6 In the diagram, (+) indicates that phase A current is supplied from terminal A1 to terminal A2 or phase B current is supplied from terminal B1 to terminal B2. (-) indicates that phase A current is supplied from terminal A2 to terminal A1 or phase B current is supplied from terminal B2 to terminal B1.

[0077] The motor driver 77 supplies "+I" and "-I" as the first drive current.

[0078] Corresponding to pulse P[1], it is used as the A-phase current supply "+I" and as the B-phase current supply "-I".

[0079] Corresponding to pulse P[2], it is used as the A-phase current supply "+I" and as the B-phase current supply "+I".

[0080] Corresponding to pulse P[3], it is used as the A-phase current supply "﹣I" and as the B-phase current supply "+I".

[0081] Corresponding to pulse P[4], it is used as the A-phase current supply "﹣I" and as the B-phase current supply "﹣I".

[0082] "+I" and "-I" have the same size but flow in different directions.

[0083] The magnitude of the first drive current (|I|) is, for example, 200 to 600 mA.

[0084] Furthermore, the motor driver 77 can supply a second drive current instead of the first drive current. The second drive current is larger than the first drive current. For example, the magnitude of the second drive current is 1.4 times the magnitude of the first drive current. Preferably, the magnitude of the second drive current is 1.1 to 1.8 times the magnitude of the first drive current, more preferably 1.3 to 1.5 times.

[0085] A pulse P is input to the stepper motor 66 (i.e., the motor driver 77) at a predetermined input speed V. The input speed V is constant. In this embodiment, the input speed V of the pulse P is set to a set speed Vs. For example, the set speed Vs is 100 to 500 pps (pulses per second). The stepper motor 66 is controlled in full-step mode. The stepper motor 66 can also be controlled in half-step mode or micro-step mode. The step angle of the stepper motor 66 is, for example, 5 degrees or 7.5 degrees.

[0086] Computer 80 is a microcomputer that integrates a CPU, ROM, RAM, input / output interface (I / O), and analog-to-digital converter (ADC) into a single package. Computer 80 may also include non-volatile memory 75, communication device 76, and motor driver 77. Computer 80 is a processing device.

[0087] The inventors investigated the relationship between the angular velocity of rotor 41 and the misalignment of stepper motor 66 when an electric valve device 1 inputs a pulse P to stepper motor 66 to rotate rotor 41.

[0088] The calculated angular velocity Cc of rotor 41 is obtained by multiplying the step angle by the input velocity V of pulse P. For example, when the step angle is 5 degrees and the input velocity V of pulse P is 500 pps, the calculated value Cc is 2500 degrees / second. For example, when the step angle is 7.5 degrees and the input velocity V of pulse P is 300 pps, the calculated value Cc is 2250 degrees / second.

[0089] Figure 7 This example schematically illustrates the relationship between the number of pulses P input to the stepper motor 66 at an input speed V and the angular velocity of the rotor 41. Figure 7 The horizontal axis represents the number of pulses P input, and the vertical axis represents the angular velocity of rotor 41. When pulse P is input to stepper motor 66 at input speed V, the angular velocity of rotor 41 increases from 0, exceeds the calculated value Cc, and reaches a peak value Cp corresponding to input speed V. Then, the angular velocity of rotor 41 decreases after reaching the peak value Cp, and its value stabilizes approximately at or near the calculated value Cc. That is, the angular velocity of rotor 41 overshoots. The peak value Cp is the maximum value of the angular velocity of rotor 41 when pulse P is input to stepper motor 66 at input speed V, and can be, for example, 150% to 250% of the calculated value Cc. The peak value Cp is measured using electric valve device 1 or calculated by simulation.

[0090] When pulse P is input to stepper motor 66, rotor 41 rotates. Specifically, when the first pulse P is input to stepper motor 66, rotor 41 rotates from its current position R0 towards position R1, which has advanced by a step angle. When the second pulse P is input to stepper motor 66, rotor 41 rotates from position R1 towards position R2, which has advanced by a step angle. When the third pulse P is input to stepper motor 66, rotor 41 rotates from position R2 towards position R3, which has advanced by a step angle. When the fourth pulse P is input to stepper motor 66, rotor 41 rotates from position R3 towards position R4, which has advanced by a step angle. Rotor 41 rotates similarly when the fifth and subsequent pulses P are input.

[0091] The inventors input four pulses P to the stepper motor 66 at a set speed Vs. The drive current corresponding to pulse P is of normal magnitude (i.e., the first drive current). The angular velocity of the rotor 41 increases according to the input of the first to the fourth pulses P. Figure 8 The angular velocity of rotor 41 does not reach its peak Cp before the input of the fourth pulse P, which is the final pulse P. In this case, after the fourth pulse P is input, the angular velocity of rotor 41 does not decrease to 0 near position R4, and sometimes rotor 41 over-rotates. Figure 8 This is a graph illustrating the relationship between the number of pulses P input and the angular velocity of the rotor 41 when four pulses P are input to the stepper motor 66 at a set speed Vs.

[0092] Furthermore, the inventors input five pulses P to the stepper motor 66 at a set speed Vs. The drive current corresponding to pulse P is the first drive current. The angular velocity of rotor 41 increases according to the input of the first to fourth pulses P, and decreases before the input of the fifth pulse P (not shown). The angular velocity of rotor 41 reaches its peak value Cp before the input of the fifth pulse P, which is the final pulse P. In this case, after the input of the fifth pulse P, the angular velocity of rotor 41 decreases to 0 near position R5, and rotor 41 stops at the correct position.

[0093] In the electric valve device 1 used by the inventors, the angular velocity of the rotor 41 reaches its peak value Cp after the fourth pulse P is input, and decreases compared to the peak value Cp before the fifth pulse P is input. Therefore, in the electric valve device 1, when pulse P is input to the stepper motor 66 at a set speed Vs, the number of pulses P required for the angular velocity of the rotor 41 to reach the peak value Cp corresponding to the set speed Vs from 0 is 4.

[0094] Furthermore, as the drive current increases, the magnetic force generated by the stator 60 becomes stronger. Therefore, by using a second drive current that is larger than the first drive current as the drive current corresponding to the pulse P, the pole teeth of the stator 60 more strongly attract the magnetic poles of the rotor 41, suppressing excessive rotation of the rotor 41.

[0095] Figure 9 The diagram schematically illustrates the waveform of the drive current (phase A current, phase B current) flowing through the A-phase coil 61c and B-phase coil 62c of the stator 60 when pulse P is input to the stepper motor 66 in ascending order.

[0096] Figure 9 The diagram above shows the waveform when the magnitude of the drive current corresponding to multiple pulses P is set to a constant (|I|). The drive current is a rectangular wave that alternately changes between a first current value (﹣I) and a second current value (+I). Alternatively, the first current value can be "+I" and the second current value can be "﹣I". Figure 9 The figure below shows the waveform when the driving current corresponding to the last two pulses P (P[1], P[2]) among multiple pulses P is greater than the driving current corresponding to the pulses P (P[1]~P[4]) before the last two pulses P (1.4 times).

[0097] Based on this result, we can know (i) to (iii).

[0098] (i) When multiple pulses P are input to the stepper motor 66, the angular velocity of the rotor 41 increases toward the peak value Cp corresponding to the input velocity V of the pulses P.

[0099] (ii) If the angular velocity of rotor 41 does not reach its peak value Cp before the last pulse P in the input of multiple pulses P, the stepper motor 66 is prone to misalignment. If the angular velocity of rotor 41 reaches its peak value Cp before the last pulse P in the input of multiple pulses P, the stepper motor 66 is unlikely to misalign. (In other words, if the angular velocity of rotor 41 increases when the last pulse P is input, the stepper motor 66 is prone to misalignment. If the increase in the angular velocity of rotor 41 is suppressed when the last pulse P is input, the stepper motor 66 is unlikely to misalign.)

[0100] (iii) If the drive current supplied to the stator 60 is relatively large, it is difficult to cause misalignment of the stepper motor 66.

[0101] Next, refer to Figures 10-13 An example of the actions performed by the electric valve control device 70 (specifically, the computer 80) will be described.

[0102] (Example of the first action)

[0103] Figure 10 This is a flowchart illustrating the first action of the electric valve control device 70.

[0104] The electric valve control device 70 receives a command from the air conditioning control device 110 to change the valve opening as the opening degree of the valve port 13 (S10). This command includes the target valve opening degree. The electric valve control device 70 calculates a control number M (S20). The control number M is the number of pulses P input to the stepper motor 66 (i.e., the motor driver 77) to rotate the rotor 41 from the current position corresponding to the current valve opening degree to the target position corresponding to the target valve opening degree. Alternatively, the electric valve control device 70 may obtain the control number M through calculation, but it is also possible that the command to change the valve opening degree includes the control number M, from which the electric valve control device 70 obtains the control number M.

[0105] The electric valve control device 70 supplies a first drive current corresponding to (M-1) pulses P to the stator 60 at a set speed Vs, thereby causing the rotor 41 to rotate (S30). Then, the electric valve control device 70 supplies a second drive current corresponding to one pulse P to the stator 60 at a set speed Vs, thereby causing the rotor 41 to rotate (S40). That is, the electric valve control device 70 makes the drive current corresponding to the last pulse P greater than the drive current corresponding to the pulses P before the last pulse P. As a result, the pole teeth of the stator 60 more strongly attract the magnetic poles of the rotor 41, and when the input of M pulses P ends, the rotor 41 stops at the target position.

[0106] In this example, the second drive current can be supplied from the beginning to the end of the cycle of the last pulse P, or it can be supplied from the middle to the end of the cycle. The second drive current can be provided during at least a portion of the cycle of the last pulse P.

[0107] (Example of the second action)

[0108] In the structure for executing the second action example, the non-volatile memory 75 stores the peak pulse number N and constant S used by the computer 80.

[0109] The peak pulse number N is the number of pulses P required for the rotor 41 to reach the peak value Cp corresponding to the set speed Vs when pulses P are input to the stepper motor 66 at a set speed Vs, from 0. That is, when N pulses P are input to the stepper motor 66 at a set speed Vs, causing the rotor 41 to rotate, the angular velocity of the rotor 41 reaches the peak value Cp from 0. Before the input of the (N+1)th pulse P, the angular velocity of the rotor 41 is smaller than the peak value Cp. The peak pulse number N is measured using the electric valve device 1 or calculated through simulation. In this embodiment, the peak pulse number N is 4.

[0110] The constant S is a natural number greater than 1 and less than N. When the electric valve control device 70 inputs multiple pulses P to the stepper motor 66 at a set speed Vs to rotate the rotor 41, if the angular velocity of the rotor 41 has not reached its peak value Cp before the last pulse P among the input multiple pulses P, the drive current corresponding to the last S pulses P is increased. In this embodiment, the constant S is 1. The constant S is preferably 1 to 5, and is appropriately set according to the structure of the electric valve 5.

[0111] Figure 11 This is a flowchart illustrating a second action example of the electric valve control device 70.

[0112] The electric valve control device 70 receives a command to change the valve opening degree from the air conditioning control device 110 (S110) and calculates the control number M (S120).

[0113] When the control number M is greater than the peak pulse number N (S130: Yes), the electric valve control device 70 determines that the angular velocity of the rotor 41 reaches the peak value Cp corresponding to the set speed Vs before the last pulse P of the input M pulses P. It then supplies the stator 60 with a first drive current corresponding to the M pulses P by inputting M pulses P to the motor driver 77 at the set speed Vs, thereby causing the rotor 41 to rotate (S140). That is, the electric valve control device 70 supplies the first drive current corresponding to the first to the Mth pulses P (keeping the magnitude of the drive current corresponding to the multiple pulses P constant from beginning to end). As a result, the angular velocity of the rotor 41 increases to the peak value Cp corresponding to the set speed Vs, then decreases, and stabilizes approximately at or near the calculated value Cc. The calculated value Cc is the value obtained by multiplying the step angle by the set speed Vs. Then, when the input of the M pulses P ends, the rotor 41 stops at the target position.

[0114] When the control number M is less than or equal to the peak pulse number N (S130: No), the electric valve control device 70 determines that the angular velocity of the rotor 41 has not reached the peak value Cp corresponding to the set speed Vs before the last pulse P in the input M pulses P.

[0115] When the control number M is greater than the constant S (S150: Yes), the electric valve control device 70 inputs (M-S) pulses P to the motor driver 77 at a set speed Vs, thereby supplying the stator 60 with a first drive current corresponding to the (M-S) pulses P, causing the rotor 41 to rotate (S160). Next, the electric valve control device 70 inputs S pulses P to the motor driver 77 at a set speed Vs, thereby supplying the stator 60 with a second drive current corresponding to the S pulses P, causing the rotor 41 to rotate (S170). That is, the electric valve control device 70 makes the drive current corresponding to the last S pulses P greater than the drive current corresponding to the pulses P preceding those last S pulses P. As a result, the pole teeth of the stator 60 more strongly attract the magnetic poles of the rotor 41, and when the input of the M pulses P ends, the rotor 41 stops at the target position.

[0116] When the control number M is less than or equal to a constant S (S150: No), the electric valve control device 70 supplies the stator 60 with a second drive current corresponding to the M pulses P by inputting M pulses P to the motor driver 77 at a set speed Vs, thereby causing the rotor 41 to rotate (S180). As a result, the pole teeth of the stator 60 more strongly attract the magnetic poles of the rotor 41, and when the input of the M pulses P ends, the rotor 41 stops at the target position.

[0117] Furthermore, the electric valve device 1 has the following structure: the angular velocity of the rotor 41 reaches its peak value Cp on the (N-1)th and Nth pulses P, and before the (N+1)th pulse P is input to the stepper motor 66, the angular velocity of the rotor 41 is lower than the peak value Cp. In this structure, the electric valve control device 70 also performs the same operation as described above. For example, in the structure where the angular velocity of the rotor 41 reaches its peak value Cp on the third and fourth pulses P, the number of peak pulses N is set to 4. When the constant S is 1 and the control number M is 3, the electric valve control device 70 supplies a first drive current to the stator 60 corresponding to the first to second pulses P, and supplies a second drive current to the stator 60 corresponding to the third pulse P. When the constant S is 1 and the control number M is 4, the electric valve control device 70 supplies a first drive current to the stator 60 corresponding to the first to third pulses P, and supplies a second drive current to the stator 60 corresponding to the fourth pulse P.

[0118] (Example of the third action)

[0119] In the structure for executing the third action example, the number of peak pulses N used by the computer 80 is stored in the non-volatile memory 75.

[0120] Figure 12 This is a flowchart illustrating the third action example of the electric valve control device 70.

[0121] The electric valve control device 70 receives a command to change the valve opening degree from the air conditioning control device 110 (S210) and calculates the control number M (S220).

[0122] When the control number M is greater than the peak pulse number N (S230: Yes), the electric valve control device 70 determines that the angular velocity of the rotor 41 reaches the peak value Cp corresponding to the set speed Vs before the last pulse P of the input M pulses P. It then inputs M pulses P to the motor driver 77 at the set speed Vs, thereby supplying the stator 60 with a first drive current corresponding to the M pulses P, causing the rotor 41 to rotate (S240). As a result, the angular velocity of the rotor 41 increases to the peak value Cp corresponding to the set speed Vs, then decreases, and stabilizes approximately at or near the calculated value Cc. Then, when the input of the M pulses P ends, the rotor 41 stops at the target position. The actions of steps S210 to S240 are similar to... Figure 11 The actions in steps S110 to S140 are the same.

[0123] When the control number M is less than or equal to the peak pulse number N (S230: No), the electric valve control device 70 determines that the angular velocity of the rotor 41 has not reached the peak value Cp corresponding to the set speed Vs before the last pulse P of the input M pulses P. It then inputs M pulses P to the motor driver 77 at the set speed Vs, thereby supplying the stator 60 with a second drive current corresponding to the M pulses P, causing the rotor 41 to rotate (S250). As a result, the pole teeth of the stator 60 more strongly attract the magnetic poles of the rotor 41, and when the input of the M pulses P ends, the rotor 41 stops at the target position.

[0124] The method for setting the peak pulse number N used in the second and third action examples will be explained.

[0125] The angular velocity of rotor 41 is related to the voltage generated in stator 60 (the electromagnetically induced voltage in stator 60) by the rotation of rotor 41. This voltage is called back electromotive force (EMF). The higher the angular velocity of rotor 41, the greater the back EMF. Therefore, the back EMF is at its maximum when the angular velocity of rotor 41 reaches its peak value Cp. Therefore, by inputting pulses P to stepper motor 66 at a set speed Vs to rotate rotor 41, and observing the back EMF, the number of pulses P input before the back EMF reaches its maximum value is taken as the peak pulse number N. Thus, the peak pulse number N can be obtained relatively easily.

[0126] Furthermore, the back electromotive force hinders the change in the drive current. Therefore, the angular velocity of rotor 41 is related to the time T of the change in the first drive current flowing through stator 60. The first drive current is a rectangular wave that alternates between "-I" and "+I". Figure 9 This example represents the change time T (rise time rt, fall time ft). The larger the back electromotive force, the longer the change time T. Therefore, the change time T is longest when the angular velocity of rotor 41 reaches its peak value Cp. Therefore, by inputting pulses P to the stepper motor 66, which is stationary at a set speed Vs, to rotate rotor 41, and observing the change time T, the number of pulses P input before the change time T becomes the longest is taken as the peak pulse number N. Thus, the peak pulse number N can be obtained relatively easily.

[0127] In the first to third operating examples, the electric valve control device 70 can also supply the drive current corresponding to the last pulse P for a period longer than the period of pulse P. For example, when the period of pulse P is 2 to 10 ms (the set speed Vs is 100 to 500 pps), the electric valve control device 70 supplies the drive current corresponding to the last pulse P for 500 ms. As a result, the pole teeth of the stator 60 attract the magnetic poles of the rotor 41 for a longer period of time, which can suppress the oscillation of the rotor 41 when it stops at the target position.

[0128] (Example of the fourth action)

[0129] In the configuration for executing the fourth action example, phase A coil 61c and phase B coil 62c are connected to the ADC of computer 80. Computer 80 can measure the change time T (rise time rt and fall time ft) of the first drive current flowing through phase A coil 61c and phase B coil 62c. The change time T is the time it takes for the first drive current to change from a first current value to a second current value (from "-I" to "+I" or from "+I" to "-I").

[0130] The non-volatile memory 75 stores the length determination value Lt and the tilt determination value St used by the computer 80.

[0131] The length determination value Lt is used to determine the length TL of the change time T. The length determination value Lt is set, for example, based on the length TL corresponding to the calculated value Cc and the peak value Cp of the rotor 41's angular velocity. Preferably, the length determination value Lt is longer than the length TL of the change time T corresponding to the calculated value Cc.

[0132] The slope determination value St is used to determine the slope TS of the change time T. The slope TS represents the amount of change of length TL per unit time (the amount of change of length TL relative to pulse P). The tilt determination value St is set, for example, based on the amount of change of length TL from the calculated value Cc to 80% of the peak value Cp of rotor 41 angular velocity.

[0133] Figure 13 This is a flowchart illustrating the fourth action example of the electric valve control device 70.

[0134] The electric valve control device 70 receives a command to change the valve opening degree from the air conditioning control device 110 (S310) and calculates the control number M (S320).

[0135] The electric valve control device 70 inputs (M-1) pulses P to the motor driver 77 at a set speed Vs, thereby supplying a first drive current corresponding to the (M-1) pulses to the stator 60, causing the rotor 41 to rotate (S330). The electric valve control device 70 acquires the change time T (length TL, slope TS) of the first drive current corresponding to the (M-1)th pulse P (S340).

[0136] When the slope TS of the time change T is greater than the slope determination value St (S350: Yes), the electric valve control device 70 determines that the angular velocity of the rotor 41 has not reached the peak value Cp corresponding to the set speed Vs before the input of the Mth pulse P. It then inputs the Mth pulse P to the motor driver 77 at the set speed Vs, thereby supplying the stator 60 with the second drive current corresponding to the Mth pulse P, causing the rotor 41 to rotate (S360). As a result, the pole teeth of the stator 60 more strongly attract the magnetic poles of the rotor 41, and when the input of the Mth pulse P ends, the rotor 41 stops at the target position.

[0137] When the length TL of the change time T is longer than the length determination value Lt (S350: No, S370: Yes), the electric valve control device 70 determines that the angular velocity of the rotor 41 has not reached the peak value Cp corresponding to the set speed Vs before the input of the Mth pulse P. It then inputs the Mth pulse P to the motor driver 77 at the set speed Vs, thereby supplying the stator 60 with the second drive current corresponding to the Mth pulse P, causing the rotor 41 to rotate (S360). As a result, the pole teeth of the stator 60 more strongly attract the magnetic poles of the rotor 41, and when the input of the Mth pulse P ends, the rotor 41 stops at the target position.

[0138] When the slope TS of the time change T is below the slope determination value St and the length TL of the time change T is below the length determination value Lt (S350: No, S370: No), the electric valve control device 70 determines that the angular velocity of the rotor 41 reaches the peak value Cp corresponding to the set speed Vs before the input of the Mth pulse P. By inputting the Mth pulse P to the motor driver 77 at the set speed Vs, the first drive current corresponding to the Mth pulse is supplied to the stator 60 to make the rotor 41 rotate (S380). Then, when the input of the Mth pulse P ends, the rotor 41 stops at the target position.

[0139] In the fourth action example, the electric valve control device 70 may also use only one of the length TL and the slope TS of the change time T to determine whether the angular velocity of the rotor 41 reaches the peak value Cp corresponding to the set speed Vs before the input of the Mth pulse P.

[0140] As described above, the electric valve device 1 includes an electric valve 5 and an electric valve control device 70. The electric valve 5 includes: a valve body 10 with a valve port 13; a stepper motor 66 with a rotor 41 and a stator 60 connected to a motor driver 77; and a valve core 20 that moves relative to the valve port 13 when the rotor 41 rotates. Multiple pulses P are input to the stepper motor 66 (i.e., the motor driver 77) to rotate the rotor 41. The electric valve control device 70 includes a computer 80. The computer 80 supplies a drive current corresponding to the multiple pulses P to the stator 60, thereby rotating the rotor 41, by inputting multiple pulses P to the motor driver 77. The computer 80 makes the drive current corresponding to the last S pulses P greater than the drive current corresponding to the pulses P preceding the last S pulses P. S is a number greater than or equal to 1 and less than or equal to the peak pulse number N. Therefore, when the last S pulses P are input, the pole teeth of the stator 60 strongly attract the magnetic poles of the rotor 41. Thus, by not always supplying a relatively large drive current to the stator 60, over-rotation of the rotor 41 can be suppressed. Therefore, it is possible to suppress the misalignment of the stepper motor 66 and the decrease in the durability of the electric valve 5.

[0141] Furthermore, the computer 80 inputs multiple pulses P to the motor driver 77 at a set speed Vs. When the computer 80 determines that the angular velocity of the rotor 41 has not reached the peak value Cp corresponding to the set speed Vs before the last pulse P among the input multiple pulses P, it makes the drive current corresponding to the last S pulses P greater than the drive current corresponding to the pulses P before the last S pulses P. When the computer 80 determines that the angular velocity of the rotor 41 reaches the peak value Cp before the last pulse P is input, it keeps the magnitude of the drive current corresponding to the multiple pulses P constant from the beginning to the end. This reduces the power consumption of the electric valve 5.

[0142] Furthermore, let M be the number of pulses P input to the motor driver 77 to rotate the rotor 41 from its current position to the target position, let N be the number of pulses P required for the angular velocity of the rotor 41 to reach the peak value Cp corresponding to the set speed Vs when pulses P are input to the motor driver 77 at a set speed Vs, and let S be the natural number greater than 1 and less than N. When the computer 80 rotates the rotor 41 from its current position to the target position, it acquires M. When M > N, the computer 80 supplies the stator 60 with a first drive current corresponding to M pulses P by inputting M pulses P to the motor driver 77 at a set speed Vs. When M > S and M ≤ N, the computer 80 supplies the stator 60 with a first drive current corresponding to (M - S) pulses P by inputting (M - S) pulses P to the motor driver 77 at a set speed Vs, and then supplies the stator 60 with a second drive current greater than the first drive current corresponding to the S pulses P by inputting S pulses P to the motor driver 77 at a set speed Vs. When M ≤ S, the computer 80 inputs M pulses P to the motor driver 77 at a set speed Vs, thereby supplying a second drive current corresponding to the M pulses P to the stator 60. Thus, through relatively simple processing, the misalignment of the stepper motor 66 and the decrease in the durability of the electric valve 5 can be suppressed.

[0143] Furthermore, when the computer 80 rotates the rotor 41 from its current position to the target position, it acquires M. When M > N, the computer 80 inputs M pulses P to the motor driver 77 at a set speed Vs, thereby supplying the stator 60 with a first drive current corresponding to the M pulses P. When M ≤ N, the computer 80 inputs M pulses P to the motor driver 77 at a set speed Vs, thereby supplying the stator 60 with a second drive current greater than the first drive current corresponding to the M pulses P. Thus, through a relatively simple process, the misalignment of the stepper motor 66 and the decrease in the durability of the electric valve 5 can be suppressed.

[0144] Furthermore, when the computer 80 rotates the rotor 41 from its current position to the target position, it acquires M. The computer 80 supplies the stator 60 with a first drive current corresponding to (M-1) pulses P by inputting (M-1) pulses P to the motor driver 77 at a set speed Vs. Based on the change time T of the first drive current corresponding to the (M-1) pulses P flowing through the stator 60, the computer 80 determines whether the angular velocity of the rotor 41 has reached its peak value Cp before the input of the Mth pulse P. When the computer 80 determines that the angular velocity of the rotor 41 has reached its peak value Cp, it supplies the stator 60 with a first drive current corresponding to the Mth pulse P by inputting the Mth pulse P to the motor driver 77 at a set speed Vs. When the computer 80 determines that the angular velocity of the rotor 41 has not reached its peak value Cp, it supplies the stator 60 with a second drive current corresponding to the Mth pulse P by inputting the Mth pulse P to the motor driver 77 at a set speed Vs. Therefore, through relatively simple processing, the misalignment of the stepper motor 66 and the decrease in the durability of the electric valve 5 can be suppressed.

[0145] In addition, the electric valve control device 70 (computer 80) may, for example, have the following structure: based on the angular velocity of the rotor 41 obtained by using a sensor, it determines whether the angular velocity of the rotor 41 has reached the peak value Cp corresponding to the input velocity V of the pulse P before the last pulse P of the input multiple pulses P.

[0146] Alternatively, the electric valve control device 70 may also have a structure that increases the input speed V of multiple pulses P when inputting multiple pulses P. For example, the electric valve control device 70 starts inputting multiple pulses P at a second speed V2, and then inputs pulses P at a first speed V1, which is higher than the second speed V2, starting from the middle of inputting multiple pulses P. In this structure, when the electric valve control device 70 determines that the angular velocity of the rotor 41 has not reached the first peak value Cp1 corresponding to the first speed V1 switched from the second speed V2 before the last pulse P in the input multiple pulses P, it makes the drive current corresponding to the last S pulses P greater than the drive current corresponding to the pulses P before the last S pulses P.

[0147] The electric valve 5 described above slows down the rotation of the rotor 41 and transmits the rotation to the drive shaft 31. The electric valve 5 can also be a direct-acting electric valve that directly transmits the rotation of the rotor 41 to the drive shaft 31.

[0148] In this specification, the terms "cylinder," "cylindrical," etc., are also used for parts or portions of parts that substantially have the shape described in the term. For example, "cylinder-shaped part" includes both cylindrical parts and substantially cylindrical parts. Furthermore, in this specification, the term "same" includes cases of strict sameness and cases of substantial sameness.

[0149] The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Those skilled in the art can appropriately add or delete constituent elements, modify the structure, or combine features of the embodiments as needed, provided that such modifications do not depart from the spirit of the present invention, and these modifications are also included within the scope of the present invention.

[0150] Symbol Explanation

[0151] 1… Electric valve device, 5… Electric valve, 10… Valve body, 12… Valve chamber, 13… Valve port, 18… Housing, 20… Valve core, 30… Drive mechanism, 31… Drive shaft, 32t… External thread, 35… Bearing component, 35t… Internal thread, 41… Rotor, 50… Planetary gear mechanism, 60… Stator, 61… Phase A stacked, 61c… Phase A coil, 62… Phase B stacked, 62c… Phase B coil, 66… Stepper motor, 70… Electric valve control device, 77… Motor driver, 80… Computer, 100… Air conditioner, 110… Air conditioner control device.

Claims

1. An electric valve control device for controlling an electric valve, the electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator connected to a motor driver; and a valve core that moves relative to the valve port when the rotor rotates, characterized in that, The electric valve control device has a processing unit. The processing device causes the rotor to rotate by inputting multiple pulses to the motor driver, thereby supplying a drive current corresponding to the multiple pulses to the stator. The processing device makes the drive current corresponding to the last at least one of the plurality of pulses greater than the drive current corresponding to the pulses preceding the last at least one pulse.

2. The electric valve control device according to claim 1, characterized in that, The processing device inputs the plurality of pulses to the motor driver at a predetermined input speed. When it is determined that the rotor's angular velocity has not reached the peak value corresponding to the predetermined input speed before the last pulse in the plurality of pulses is input, the processing device makes the drive current corresponding to the last at least one pulse larger than the drive current corresponding to the pulses preceding the last at least one pulse. When it is determined that the rotor's angular velocity reached the peak value before the last pulse was input, the processing device keeps the magnitude of the drive current corresponding to the plurality of pulses constant.

3. The electric valve control device according to claim 2, characterized in that, Let M be the number of pulses input to the motor driver to rotate the rotor from the current position to the target position. Let N be the number of pulses required for the rotor's angular velocity to reach its peak value from 0 when pulses are input to the motor driver at the specified input speed. When we define a natural number greater than 1 and less than N as S, When the processing device rotates the rotor from the current position to the target position, M is obtained. When M > N, the processing device supplies the stator with a first driving current corresponding to the M pulses by inputting M pulses to the motor driver at the specified input speed. When M ≤ N and M > S, the processing device supplies the stator with a first drive current corresponding to (M-S) pulses by inputting (M-S) pulses to the motor driver at the predetermined input speed, and then supplies the stator with a second drive current greater than the first drive current corresponding to the S pulses by inputting S pulses to the motor driver at the predetermined input speed. When M≤S, the processing device supplies the stator with the second driving current corresponding to the M pulses by inputting M pulses to the motor driver at the specified input speed.

4. The electric valve control device according to claim 2, characterized in that, Let M be the number of pulses input to the motor driver to rotate the rotor from the current position to the target position. When the number of pulses required for the rotor's angular velocity to reach its peak value from 0 when pulses are input to the motor driver at the specified input speed is set to N, When the processing device rotates the rotor from the current position to the target position, it acquires M. When M > N, the processing device supplies the stator with a first driving current corresponding to the M pulses by inputting M pulses to the motor driver at the specified input speed. When M≤N, the processing device supplies the stator with a second driving current that is larger than the first driving current, corresponding to the M pulses, by inputting M pulses to the motor driver at the specified input speed.

5. The electric valve control device according to claim 3 or 4, characterized in that, The number of pulses required for the rotor's angular velocity to reach the peak value from 0 is set based on the back electromotive force generated in the stator when the rotor rotates by supplying the first drive current corresponding to the pulse to the stator.

6. The electric valve control device according to claim 3 or 4, characterized in that, The first driving current is a current that alternately changes between a first current value and a second current value. The number of pulses required for the rotor's angular velocity to reach the peak value from 0 is set based on the time it takes for the first drive current flowing through the stator to change from the first current value to the second current value when the rotor rotates by supplying the first drive current to the stator.

7. The electric valve control device according to claim 2, characterized in that, The drive current includes a first drive current and a second drive current that is larger than the first drive current. The first driving current is a current that alternately changes between a first current value and a second current value. When the number of pulses input to the motor driver to rotate the rotor from the current position to the target position is set to M, When the processing device rotates the rotor from the current position to the target position, M is obtained. The processing device supplies the stator with the first driving current corresponding to (M-1) pulses by inputting (M-1) pulses to the motor driver at the specified input speed. The processing device determines whether the rotor's angular velocity reached the peak value before the Mth pulse was input, based on the change time of the first drive current corresponding to the (M-1)th pulse flowing through the stator from the first current value to the second current value. When it is determined that the angular velocity of the rotor has reached the peak value, the processing device inputs the Mth pulse to the motor driver at the predetermined input speed, thereby supplying the stator with the first drive current corresponding to the Mth pulse. When it is determined that the angular velocity of the rotor has not reached the peak value, the processing device supplies the stator with the second driving current corresponding to the Mth pulse by inputting the Mth pulse to the motor driver at the specified input speed.

8. An electric valve device, characterized in that, The device comprises the electric valve control device and the electric valve as described in claim 1.

9. A method for controlling an electric valve, the electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator connected to a motor driver; and a valve core that moves relative to the valve port when the rotor rotates, characterized in that, By inputting multiple pulses to the motor driver, a drive current corresponding to the multiple pulses is supplied to the stator, thereby causing the rotor to rotate. The drive current corresponding to the last at least one of the plurality of pulses is greater than the drive current corresponding to the pulse preceding the last at least one pulse.

10. The control method for the electric valve according to claim 9, characterized in that, The plurality of pulses are input to the motor driver at a specified input speed. If it is determined that the rotor's angular velocity has not reached the peak value corresponding to the specified input speed before the last pulse in the plurality of pulses is input, then the drive current corresponding to the last at least one pulse is made greater than the drive current corresponding to the pulses preceding the last at least one pulse. When it is determined that the rotor's angular velocity reached the peak value before the last pulse was input, the magnitude of the drive current corresponding to the plurality of pulses is kept constant.

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