Electrically operated valve control device, electrically operated valve device, and method for determining state of electrically operated valve

Abstract

Provided are an electrically operated valve control device, an electrically operated valve device having the electrically operated valve control device, and a method for determining the state of an electrically operated valve, with which it is possible to determine, at an appropriate timing, whether or not the rotation of a rotor of a stepping motor is restricted. A drive current for rotating a rotor (41) is supplied to a coil of a stator (60) of a stepping motor (66), said drive current being controlled in a punching width modulation manner. A low-pass filter of the electrically operated valve control device (70) has a cut-off frequency lower than a pulse width modulation frequency used in the pulse width modulation scheme, and the low-pass filter passes a voltage component of a frequency lower than the cut-off frequency among the voltages generated in the coil. A computer of the electrically operated valve control device (70) determines whether or not the electrically operated valve (5) is in a rotation restriction state in which the rotation of the rotor (41) is restricted by using the voltage component that has passed through the low-pass filter.

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 determining the state of an electric valve. Background Technology

[0002] Patent Document 1 discloses an example of a conventional electric valve. The electric valve is, for example, assembled in the refrigeration cycle system of an air conditioner. The electric valve has a valve body, a valve core, and a stepper motor for moving the valve core. The stepper motor has a rotor and a stator. The stator has coils. 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 of the stepper motor, the rotor rotates. The valve core moves in response to the rotation of the rotor. When the rotor is in a reference position, a movable stop that rotates with the rotor abuts against a fixed stop fixed to the valve body, thereby limiting the rotation of the rotor in a first direction.

[0003] The electric valve is controlled by an electric valve control device. During the initialization operation, the electric valve control device inputs pulses to the stepper motor, causing the rotor to rotate in the first direction and positioning the rotor in a reference position. The number of pulses input to the stepper motor is a sufficient number to cause the movable stop to abut against the fixed stop (hereinafter referred to as the "initialization number"). When the rotor rotates in the first direction and the movable stop abuts against the fixed stop, the rotor is positioned in the reference position.

[0004] The electric valve control device inputs pulses to the stepper motor until the number of pulses input to the stepper motor reaches the initialization number. Therefore, the electric valve control device sometimes inputs pulses even after the rotor is positioned at the reference position, resulting in a longer initialization time. Furthermore, when pulses are input to the stepper motor after the rotor is positioned at the reference position, the movable stop and the fixed stop repeatedly collide, generating noise. This noise is particularly prolonged when the rotor is close to the reference position just before the initialization operation begins.

[0005] During initialization, the waveform of the voltage generated in the stator by the rotor's rotation (the voltage electromagnetically induced in the stator) differs before and after the rotor's rotation is restricted. The electric valve control device disclosed in Patent Document 2 acquires the voltage generated in the stator by the rotor's rotation and determines whether the rotor's rotation in a first direction is restricted based on the degree of difference between the voltage waveform and a reference voltage waveform. When the electric valve control device determines that the rotor's rotation in the first direction is restricted, it stops the rotor's rotation. Therefore, the electric valve control device stops the rotor's rotation immediately after it is positioned at a reference position, suppressing prolonged noise generation.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese International Publication No. 2019 / 130928.

[0009] Patent Document 2: Japanese Patent No. 7254400.

[0010] The technical problem that the invention aims to solve

[0011] The stator has an A-phase stator and a B-phase stator. When drive current is supplied to both the A-phase and B-phase stators, the voltage generated in the A-phase stator includes a voltage component generated by the drive current and a voltage component generated by the rotor's rotation. The voltage generated in the B-phase stator also includes a voltage component generated by the drive current and a voltage component generated by the rotor's rotation. In the structure where the drive current is controlled by pulse width modulation, the voltage component generated by the drive current has a relatively high frequency and a large amplitude, while the voltage component generated by the rotor's rotation is hidden within the voltage component generated by the drive current.

[0012] Therefore, when only one of the A-phase stator and the B-phase stator is supplied with drive current, the electric valve control device in Patent Document 2 determines whether the rotation of the rotor in the first direction is restricted based on the voltage generated in the other phase where no drive current is supplied. When drive current is supplied to both the A-phase stator and the B-phase stator, the electric valve control device cannot determine whether the rotation of the rotor in the first direction is restricted. Therefore, the electric valve control device sometimes cannot make a determination when the rotation of the rotor in the first direction is actually restricted. Summary of the Invention

[0013] Therefore, the object of the present invention is to provide an electric valve control device capable of determining at appropriate times whether the rotation of the rotor of a stepper motor is restricted, an electric valve device having an electric valve control device, and a method for determining the state of the electric valve.

[0014] Technical means for solving technical problems

[0015] To achieve the above objectives, one aspect of the present invention provides 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; and a valve core that moves relative to the valve port when the rotor rotates. The electric valve control device includes a low-pass filter and a processing unit that supplies a drive current controlled by pulse width modulation (PWM) for rotating the rotor to a coil of the stator. The low-pass filter has a cutoff frequency lower than the PWM frequency used in the PWM method, and the low-pass filter allows voltage components of the voltage generated in the coil at frequencies lower than the cutoff frequency to pass through. The processing unit uses the voltage components that have passed through the low-pass filter to determine whether the electric valve is in a rotation-limited state where the rotation of the rotor is restricted.

[0016] In this invention, preferably, the processing device determines whether the electric valve is in the rotation restriction state based on the degree of difference between the waveform of the voltage component and the reference waveform of the voltage component.

[0017] In this invention, preferably, the coil is connected to a motor driver. When multiple pulses with consecutive numbers are sequentially and repeatedly input to the motor driver, the motor driver supplies the driving current corresponding to the multiple pulses to the coil to rotate the rotor. The processing device starts inputting the multiple pulses to the motor driver. When the driving current corresponding to the pulses input to the motor driver is supplied to the coil, the processing device acquires the voltage component. The pulses input to the motor driver are referred to as the determination target pulses, and the voltage component is used to determine whether the electric valve is in the rotation restriction state. When the electric valve is determined to be in the rotation restriction state, the processing device stops inputting the multiple pulses before inputting the next pulse of the determination target pulse.

[0018] In this invention, preferably, the coil is connected to a motor driver. When multiple pulses with consecutive numbers are sequentially and repeatedly input to the motor driver, the motor driver supplies the driving current corresponding to the multiple pulses to the coil to rotate the rotor. The processing device starts inputting the multiple pulses to the motor driver. When the driving current corresponding to the pulses input to the motor driver is supplied to the coil, the processing device acquires the voltage component. The pulses input to the motor driver are referred to as the determination target pulses. During the input of the next pulse of the determination target pulse, the processing device uses the voltage component to determine whether the electric valve is in the rotation restriction state. When the electric valve is determined to be in the rotation restriction state, the processing device inputs a pulse with the same number as the determination target pulse to the motor driver following the next pulse of the determination target pulse, and stops inputting the multiple pulses.

[0019] In this invention, preferably, the coil is connected to a motor driver. When a plurality of pulses with consecutive numbers are sequentially and repeatedly input to the motor driver, the motor driver supplies the driving current corresponding to the plurality of pulses to the coil to rotate the rotor. The processing device begins to input the plurality of pulses to the motor driver. When the driving current corresponding to the pulses input to the motor driver is supplied to the coil, the processing device acquires the voltage component. The pulses input to the motor driver are referred to as the determination target pulses. During the input of the next pulse of the determination target pulse, the processing device uses the voltage component to determine whether the electric valve is in the rotation restriction state. When the electric valve is determined to be in the rotation restriction state, the processing device sequentially inputs the plurality of pulses to the motor driver following the next pulse of the determination target pulse until a pulse with the same number as the determination target pulse is input to the motor driver, and then stops inputting the plurality of pulses.

[0020] In this invention, it is preferred that the cutoff frequency be set based on the pulse width modulation frequency.

[0021] To achieve the above objectives, another embodiment of the present invention provides an electric valve device having the electric valve and the electric valve control device.

[0022] To achieve the above-mentioned objective, another aspect of the present invention provides a method for determining the state of an electric valve, the electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator; and a valve core that moves relative to the valve port when the rotor rotates, wherein a drive current controlled by a pulse width modulation method for rotating the rotor is supplied to a coil of the stator, a voltage generated in the coil is input to a low-pass filter having a cutoff frequency lower than the pulse width modulation frequency used in the pulse width modulation method, and the low-pass filter allows voltage components of the voltage generated in the coil at frequencies lower than the cutoff frequency to pass through, and the voltage components passing through the low-pass filter are used to determine whether the electric valve is in a rotation-limited state where the rotation of the rotor is restricted.

[0023] The effects of the invention

[0024] According to the present invention, a stepper motor has a rotor and a stator, and a drive current controlled by pulse width modulation for rotating the rotor is supplied to the coils of the stator. Then, a voltage component with a frequency lower than the cutoff frequency in the voltage generated by the coil is used to determine whether the electric valve is in a rotation-limited state where the rotor's rotation is restricted. In this way, the higher frequency voltage component generated by the drive current can be removed from the voltage generated by the coil, and the voltage component generated by the rotor's rotation can be suppressed from being hidden within the voltage component generated by the drive current. Therefore, even if a drive current is supplied to the coil, it is possible to determine whether the electric valve is in a rotation-limited state based on the voltage generated by that coil. Thus, it is possible to determine at an appropriate time whether the rotation of the stepper motor's rotor is restricted. Attached Figure Description

[0025] Figure 1 This is a block diagram of an air conditioning system with an electric valve device.

[0026] Figure 2 This is a cross-sectional view of an electric valve device.

[0027] Figure 3 This is a diagram showing the valve shaft cage of an electric valve assembly.

[0028] Figure 4 This is a side view of the guide bushing of the electric valve device.

[0029] Figure 5 This is a diagram showing the stop component of an electric valve device.

[0030] Figure 6 It is a top view of the valve shaft cage, stop components, rotor, and stator of the electric valve device.

[0031] Figure 7This is a diagram showing the computer, motor driver, low-pass filter, and stepper motor of an electric valve control device.

[0032] Figure 8 This is a diagram illustrating an example of the relationship between the step signal and direction signal input to the motor driver and the pulse input to the stepper motor.

[0033] Figure 9 This is a diagram illustrating an example of the correspondence between a pulse and the target values ​​of the A-phase current and the B-phase current.

[0034] Figure 10 This is a diagram showing examples of the waveforms of phase A current and phase B current.

[0035] Figure 11 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when the input pulse P[1] is applied).

[0036] Figure 12 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when the input pulse P[2] is applied).

[0037] Figure 13 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when the input pulse P[3] is applied).

[0038] Figure 14 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when the input pulse P[4] is applied).

[0039] Figure 15 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when the input pulse P[5] is applied).

[0040] Figure 16 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when the input pulse P[6] is applied).

[0041] Figure 17 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when the input pulse P[7] is applied).

[0042] Figure 18 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when the input pulse P[8] is applied).

[0043] Figure 19 This is a diagram showing an example of the waveform of the voltage generated in the stator coils.

[0044] Figure 20 It means Figure 19A diagram showing an example of the waveform of a voltage component at a frequency lower than the cutoff frequency.

[0045] Figure 21 This is a diagram showing an example of the waveform of the voltage component at a frequency lower than the cutoff frequency in the voltage generated by the stator coils (in a state where rotor rotation is permissible).

[0046] Figure 22 This is a diagram showing an example of the waveform of the voltage component at a frequency lower than the cutoff frequency in the voltage generated by the stator coils (in a state where the rotation of the rotor is restricted).

[0047] Figure 23 This is a diagram showing an example of the rotor's rotation angle.

[0048] Figure 24 It is a graph comparing the waveforms of voltage components at frequencies lower than the cutoff frequency in the voltage generated by the stator coils.

[0049] Figure 25 This is a diagram of an example data table representing the reference waveform of the voltage component at a frequency lower than the cutoff frequency in the voltage generated by the stator coils.

[0050] Figure 26 This is a diagram showing an example of the waveform of a voltage component at a frequency lower than the cutoff frequency in the voltage generated by the stator coils, and a reference waveform for that voltage component.

[0051] Figure 27 This is a flowchart illustrating an example of the operation of an electric valve control device (Action Example 1).

[0052] Figure 28 These are flowcharts illustrating other examples of the operation of an electric valve control device (Action Examples 2 and 3).

[0053] Figure 29 This is a diagram showing an example of the rotor's rotation angle (micro-stepping mode 1).

[0054] Figure 30 It is a graph comparing the waveforms of voltage components at frequencies lower than the cutoff frequency in the voltage generated by the stator coils (micro-stepping mode 1).

[0055] Figure 31 This is a diagram showing an example of the rotor's rotation angle (micro-stepping mode 2).

[0056] Figure 32 This is a graph comparing the waveforms of voltage components at frequencies lower than the cutoff frequency in the voltage generated by the stator coils (micro-stepping mode 2). Detailed Implementation

[0057] The following is for reference Figures 1 to 28 An electric valve device according to an embodiment of the present invention will be described.

[0058] Figure 1 This is a block diagram of an air conditioning system with an electric valve device. Figure 2 This is a cross-sectional view of an electric valve device. Figure 3 This is a diagram showing the valve shaft cage of an electric valve assembly. Figure 3 (A) is a perspective view of the valve shaft cage. Figure 3 (B) is a top view of the valve shaft cage. Figure 4 This is a side view of the guide bushing of the electric valve device. Figure 5 This is a diagram showing the stop component of an electric valve device. Figure 5 (A) is a three-dimensional view of the stop component. Figure 5 (B) is a top view of the stop component. Figure 6 This is a top view of the valve shaft cage, stop components, rotor, and stator of an electric valve assembly. Figure 6 The diagram schematically represents the rotor's magnetic poles and the stator. Figure 7 This is a diagram showing the computer, motor driver, low-pass filter, and stepper motor of an electric valve control device. Figure 8 This is a diagram illustrating an example of the relationship between the step signal and direction signal input to the motor driver and the pulse input to the stepper motor (motor driver). Figure 9 This is a diagram illustrating an example of the correspondence between a pulse and the target values ​​of the A-phase current and the B-phase current. Figure 10 This is a diagram showing examples of the waveforms of phase A current and phase B current. Figures 11-18 It is a diagram that schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth.

[0059] Figure 19 This is a diagram showing an example of the waveform of the voltage generated in the stator coils. Figure 20 It means Figure 19 The diagram shows an example of the waveform of a voltage component that has passed through a low-pass filter and has a frequency lower than the cutoff frequency. Figure 21 , Figure 22 This is a diagram showing an example of the waveform of a voltage component at a frequency lower than the cutoff frequency in the voltage generated by the stator coils. Figure 21 The waveform representing the voltage component under the condition that the rotor's rotation is permitted. Figure 22 The waveform representing the voltage component when the rotor's rotation is restricted. Figure 23 This is a diagram showing an example of the rotor's rotation angle. Figure 23 This represents the change in the rotor's rotation angle relative to the pulse input. Figure 24It is a graph comparing the waveforms of voltage components at frequencies lower than the cutoff frequency in the voltage generated by the stator coils. Figure 24 It is a graph comparing the waveform of the voltage component when the rotor rotation is allowed to occur with the waveform of the voltage component when the rotor rotation is restricted. Figure 25 This is a diagram of an example data table representing the reference waveform of the voltage component at a frequency lower than the cutoff frequency in the voltage generated by the stator coils. Figure 26 This is a diagram showing an example of the waveform of a voltage component at a frequency lower than the cutoff frequency in the voltage generated by the stator coils, and a reference waveform for that voltage component. Figure 27 , Figure 28 This is a flowchart illustrating an example of the operation of an electric valve control device. Figure 27 Example 1 represents the action. Figure 28 This refers to actions 2 and 3. Figures 19-22 , Figure 24 , Figure 26 In the graph, the horizontal axis represents time, and the vertical axis represents voltage. Figure 23 In the diagram, the horizontal axis represents time, and the vertical axis represents the rotation angle.

[0060] The electric valve device 1 in this embodiment is used, for example, as a flow control valve to control the flow rate of refrigerant as a fluid in an air conditioning system.

[0061] Figure 1 This example illustrates an air conditioning system 100 installed in a vehicle. The air conditioning system 100 includes a compressor 101, a condenser 102, an electric valve device 1 (electric valve 5), and an evaporator 103, which are sequentially connected via piping 105. The electric valve device 1 is an expansion valve. The air conditioning system 100 includes an air conditioning control device 110. The air conditioning control device 110 is communicatively connected to the electric valve device 1 (electric valve control device 70). The air conditioning control device 110 uses the electric valve device 1 to control the flow rate of refrigerant flowing in the piping 105.

[0062] like Figure 2 As shown, the electric valve device 1 has an electric valve 5 and an electric valve control device 70.

[0063] The electric valve 5 has a valve body 10, a housing 20, a valve core 30, a drive mechanism 40, and a stator 60.

[0064] The valve body 10 has a main component 11 and a connecting component 13. The main component 11 has a cylindrical shape. The main component 11 has a valve chamber 14, a valve port 17, and a valve seat 18. The main component 11 engages with a first conduit 15 and a second conduit 16. The first conduit 15 is aligned in a direction orthogonal to the axis L. Figure 2 The second conduit 16 is configured in the left-right direction and is connected to the valve chamber 14. The second conduit 16 is along the axis L (…). Figure 2The valve is configured (vertically and horizontally) and connected to the valve chamber 14 via a valve port 17. The valve port 17 is surrounded by an annular valve seat 18 within the valve chamber 14. The main body component 11 has a circular fitting hole 11a. The fitting hole 11a is located on the upper end face of the main body component 11. The inner circumferential surface of the fitting hole 11a has... Figure 2 A plane 11d extending to the left from the center. A through hole 11b leading to the valve chamber 14 is provided on the bottom surface of the fitting hole 11a. The connecting member 13 has an annular plate shape. The inner periphery of the connecting member 13 engages with the upper end of the main body member 11. The main body member 11 and the connecting member 13 are made of metals such as aluminum alloy, stainless steel, and brass.

[0065] The housing 20 is made of a metal such as stainless steel. The housing 20 has a cylindrical shape. The lower end of the housing 20 is open and the upper end is closed. The lower end of the housing 20 engages with the outer periphery of the connecting member 13.

[0066] The valve core 30 has a first shaft portion 31, a second shaft portion 32, and a valve portion 33. The first shaft portion 31 is cylindrical. The second shaft portion 32 is cylindrical. The diameter of the second shaft portion 32 is smaller than the diameter of the first shaft portion 31. The second shaft portion 32 is coaxially connected to the upper end of the first shaft portion 31. The valve core 30 has a stepped portion 34, which is an annular plane extending upwards. The stepped portion 34 is disposed at the connection between the first shaft portion 31 and the second shaft portion 32. The valve portion 33 has a generally conical shape whose diameter decreases from top to bottom. The valve portion 33 is coaxially connected to the lower end of the first shaft portion 31. The valve portion 33 is disposed at a valve port 17. A variable throttling portion is formed between the valve portion 33 and the valve port 17. The valve portion 33 is opposite to the valve port 17 and the valve seat 18. When the valve portion 33 contacts the valve seat 18, the valve port 17 is closed. When valve part 33 leaves valve seat 18, valve port 17 opens.

[0067] The drive mechanism 40 moves the valve core 30 in the vertical direction (axis L direction). The valve port 17 is opened and closed by the movement of the valve core 30. The drive mechanism 40 has a rotor 41, a valve shaft retainer 42, a guide bushing 43, a stop member 44, and a fixing member 45.

[0068] Rotor 41 has a cylindrical shape. The outer diameter of rotor 41 is slightly smaller than the inner diameter of housing 20. Rotor 41 is disposed inside housing 20. Rotor 41 is rotatable relative to valve body 10. Rotor 41 has multiple N poles and multiple S poles. The multiple N poles and multiple S poles are disposed 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 alternately arranged at equal angular intervals in the circumferential direction. Rotor 41, for example, has 12 N poles and 12 S poles. The angle between adjacent N poles and S poles is 15 degrees.

[0069] Figure 3The valve shaft retainer 42 is indicated. The valve shaft retainer 42 has a cylindrical shape. The lower end of the valve shaft retainer 42 is open. An upper wall portion 42a is provided at the upper end of the valve shaft retainer 42. The upper wall portion 42a has a shaft hole 42b. The valve shaft retainer 42 engages with the fitting hole 41a of the rotor 41. The valve shaft retainer 42 rotates together with the rotor 41. A movable stop member 42s is disposed at the lower end of the outer peripheral surface of the valve shaft retainer 42. The movable stop member 42s is a protrusion that projects radially outward. The second shaft portion 32 of the valve core 30 is disposed in the shaft hole 42b in a manner that allows it to move along the axis L. A washer 46 is disposed on the lower surface of the upper wall portion 42a of the valve shaft retainer 42. A valve closing spring 47 is disposed between the washer 46 and the stepped portion 34 of the valve core 30. The valve closing spring 47 is a coil spring that presses the valve core 30 toward the valve seat 18. An internal thread 42c is provided on the inner circumferential surface of the valve shaft retainer 42. The movable stop 42s is fixed relative to the rotor 41.

[0070] Figure 4 The guide bushing 43 is indicated. The guide bushing 43 has a base 43a and a support 43b. The base 43a has a cylindrical shape. The outer peripheral surface of the base 43a has a plane 43d. The base 43a is pressed into a fitting hole 11a of the main body component 11, with the plane 43d contacting the plane 11d of the fitting hole 11a. Thus, the central axis of the main body component 11 and the central axis of the guide bushing 43 are aligned on axis L, and the guide bushing 43 is correctly positioned relative to the main body component 11 about axis L. The support 43b has a cylindrical shape. The outer diameter of the support 43b is smaller than the outer diameter of the base 43a. The inner diameter of the support 43b is approximately the same as the inner diameter of the base 43a. The support 43b is coaxially connected to the upper end of the base 43a. An external thread 43c is provided on the outer peripheral surface of the support 43b. The external thread 43c engages with the internal thread 42c of the valve shaft retainer 42. The first shaft portion 31 of the valve core 30 is disposed inside the guide bushing 43. The guide bushing 43 supports the valve core 30 so that it can move along the axis L.

[0071] Figure 5 The stop component 44 is indicated. The stop component 44 has a stop body 44a. The stop body 44a has a cylindrical shape. An internal thread 44c is provided on the inner circumferential surface of the stop body 44a. A fixing stop 44s is disposed on the outer circumferential surface of the stop body 44a. The fixing stop 44s is a protrusion that projects radially outward. The internal thread 44c engages with the external thread 43c until the stop body 44a abuts against the base 43a of the guide bushing 43. Thus, the stop component 44 is fixed to the guide bushing 43. The fixing stop 44s is fixed relative to the valve body 10.

[0072] The fixing member 45 has a fixing portion 45a and a flange portion 45b. The fixing portion 45a has a stepped cylindrical shape. A second shaft portion 32 of the valve core 30 is disposed inside the fixing portion 45a. The fixing portion 45a engages with the second shaft portion 32. The flange portion 45b is connected to the lower end of the fixing portion 45a. A return spring 48 is disposed on the outside of the fixing member 45. The return spring 48 is a coil spring.

[0073] The electric valve 5 has a drive mechanism 40 that does not reduce the rotation of the rotor 41. Alternatively, the electric valve 5 may have a drive mechanism that reduces the rotation of the rotor 41 instead of the drive mechanism 40.

[0074] The stator 60 has a cylindrical shape. The stator 60 has an A-phase stator 61 and a B-phase stator 62.

[0075] The A-phase stator 61 has multiple claw-shaped pole teeth 61a and 61b on its inner circumference. The tips of pole teeth 61a face downwards, and the tips of pole teeth 61b face upwards. The pole teeth 61a and 61b are alternately arranged at equal angular intervals along the circumference. For example, the A-phase stator 61 has 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 of opposite polarities.

[0076] The B-phase stator 62 has multiple claw-shaped pole teeth 62a and 62b on its inner circumference. The tips of pole teeth 62a face downwards, and the tips of pole teeth 62b face upwards. The pole teeth 62a and 62b are alternately arranged at equal angular intervals along the circumference. For example, the B-phase stator 62 has 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 of opposite polarities.

[0077] Phase A stator 61 and Phase B stator 62 are coaxially arranged. Phase A stator 61 and Phase B stator 62 are in contact. When viewed from the axis L, the angle between the pole teeth 61a of the adjacent Phase A stator 61 and the pole teeth 62a of the Phase B stator 62 is 7.5 degrees. That is, the Phase B stator 62 is located at a position where the pole teeth 61a and 62a are arranged along the axis L, and rotated 7.5 degrees relative to the Phase A stator 61 about the axis L.

[0078] A housing 20 is disposed inside the stator 60. A rotor 41 is disposed inside the housing 20. The stator 60 and rotor 41 are stepper motors 66. The stepper motor 66 is connected to an electric valve control device 70.

[0079] The rotor 41 rotates by repeatedly inputting sequentially numbered pulses P (P[1]~P[8]) into the stepper motor 66. Specifically, the rotor 41 rotates by supplying a drive current corresponding to the pulse P to the stator 60 of the stepper motor 66. In this specification, "inputting pulse P into the stepper motor 66" and "supplying a drive current corresponding to the pulse P to the stator 60 of the stepper motor 66" are synonymous.

[0080] When pulses P are cyclically input to the stepper motor 66 in ascending order (pulse P[1]~P[8]), the rotor 41 moves in the first direction (in the first direction). Figure 6 The rotor 41 rotates in the second direction (clockwise). When pulses P are cyclically input to the stepper motor 66 in descending order (pulse P[8]~P[1]), the rotor 41 rotates in the second direction (in the clockwise direction). Figure 6 (The center rotates counterclockwise).

[0081] In the electric valve 5, the central axis of each of the valve port 17, valve seat 18, housing 20, valve core 30, rotor 41, valve shaft retainer 42, guide bushing 43, and stator 60 (A-phase stator 61 and B-phase stator 62) is aligned with the axis L.

[0082] The electric valve control device 70 has a base plate 71 on which multiple electronic components (not shown) are mounted. For example... Figure 1 As shown, the electric valve control device 70 includes a non-volatile memory 75, a communication device 76, a motor driver 77, a low-pass filter 78, and a computer 80. The electric valve control device 70 controls the electric valve 5 based on commands from the air conditioning control device 110.

[0083] Non-volatile memory 75 stores data that needs to be retained even when the power is disconnected. Non-volatile memory 75 is, for example, EEPROM or flash memory.

[0084] The communication device 76 is communicatively connected to the air conditioning control device 110 via a wired communication bus 120. The air conditioning system 100 may employ communication methods such as Local Interconnect Network (LIN) or Controller Area Network (CAN). Alternatively, the communication device 76 may be connected to the air conditioning control device 110 wirelessly.

[0085] The motor driver 77 is controlled by the computer 80. The motor driver 77 is connected to the stator 60 of the stepper motor 66. Specifically, as... Figure 7As shown, the motor driver 77 is connected to the A-phase coil 61c of the A-phase stator 61 and the B-phase coil 62c of the B-phase stator 62. The motor driver 77 supplies a drive current corresponding to the pulse P to the stator 60. The motor driver 77 supplies the A-phase current Ia to the A-phase coil 61c and the B-phase current Ib to the B-phase coil 62c.

[0086] As signals corresponding to pulse P, a step signal (STEP) and a direction signal (DIR) are input from computer 80 to motor driver 77. The step signal is a pulse signal. When a direction signal (e.g., an H-level signal) corresponding to the first direction is input to motor driver 77, the input of the step signal is equivalent to inputting pulse P to stepper motor 66 in ascending order. When a direction signal (e.g., an L-level signal) corresponding to the second direction is input to motor driver 77, the input of the step signal is equivalent to inputting pulse P to stepper motor 66 in descending order. Figure 8 This indicates the relationship between the step signal, the direction signal, and the pulse P input to the stepper motor 66.

[0087] Pulses P[1] to P[8] are sequentially input to the stepper motor 66. In response to the input of pulse P, phase A current Ia is supplied to phase A coil 61c, and phase B current Ib is supplied to phase B coil 62c in response to the input of pulse P. Phase A current Ia and phase B current Ib are driving currents used to rotate rotor 41.

[0088] Additionally, a current control signal (CONTROL) is input from the computer 80 to the motor driver 77. The current control signal is a signal used to set the target values ​​of the phase A current (Ita) and phase B current (Itb) to the motor driver 77 as target values ​​for phase A current (Ia) and phase B current (Ib).

[0089] Set the target value Ita of phase A current for pulses P[1] to P[8]. Set the target value Itb of phase B current for pulses P[1] to P[8]. Figure 9 An example illustrating the correspondence between pulse P and the target values ​​Ita of phase A current and Itb of phase B current.

[0090] For pulse P[1], set "+I2" as the target value Ita of phase A current and set "0" as the target value Itb of phase B current.

[0091] For pulse P[2], set "+I1" as the target value Ita of phase A current and set "+I1" as the target value Itb of phase B current.

[0092] For pulse P[3], set “0” as the target value Ita of phase A current and set “+I2” as the target value Itb of phase B current.

[0093] For pulse P[4], set "-I1" as the target value Ita of phase A current and set "+I1" as the target value Itb of phase B current.

[0094] For pulse P[5], set "-I2" as the target value Ita of phase A current and set "0" as the target value Itb of phase B current.

[0095] For pulse P[6], set "-I1" as the target value Ita of phase A current and set "-I1" as the target value Itb of phase B current.

[0096] For pulse P[7], set “0” as the target value Ita of phase A current and set “-I2” as the target value Itb of phase B current.

[0097] For pulse P[8], set "+I1" as the target value Ita of phase A current and set "-I1" as the target value Itb of phase B current.

[0098] The magnitudes of the currents "+I2" and "-I2" are the same, but their directions are different.

[0099] The magnitudes of the currents "+I1" and "-I1" are the same, but their directions are different.

[0100] The magnitudes of the currents in "+I2" and "+I1" are different, but the directions of the currents are the same.

[0101] Figure 10 The diagram schematically illustrates the waveforms of the A-phase current Ia and the B-phase current Ib when pulses P are input to the stepper motor 66 in ascending order. Figure 10 In the diagram, phase A current Ia is the current with the same magnitude and direction as the target value Ita of phase A current, and phase B current Ib is the current with the same magnitude and direction as the target value Itb of phase B current. Figure 9 , Figure 10 In this symbol, (+ / -) indicates the direction of current flow. "+" indicates the direction from terminal A1 to terminal A2, or from terminal B1 to terminal B2. "-" indicates the direction from terminal A2 to terminal A1, or from terminal B2 to terminal B1. "0" indicates no current flow.

[0102] The phase A current Ia and phase B current Ib are controlled by pulse width modulation (PWM). The phase A current Ia and phase B current Ib are waveforms that are repeatedly switched on and off at constant time intervals shorter than the period of pulse P. The reciprocal of this time interval is the pulse width modulation frequency (PWM frequency). The target values ​​Ita for phase A current and Itb for phase B current are the average values ​​of the current supplied to phase A coil 61c and phase B coil 62c during the period of pulse P.

[0103] The combination of phase A current Ia and phase B current Ib is different for each pulse P. The number of combinations is 8, which is called the number of patterns of pulse P. The “pattern” is also called the “switching mode”. The numbers (1 to 8) of pulses P[1] to P[8] are used to determine the pattern number of pulses P[1] to P[8]. For example, the period of pulse P is 8ms, and the period T containing pulses P[1] to P[8] is 64ms. The excitation mode of stepper motor 66 is 1-2 phase excitation. Stepper motor 66 is controlled by half-stepping. The step angle of stepper motor 66 is 3.75 degrees.

[0104] Figures 11-18 The diagram schematically illustrates the positional relationship between the rotor's magnetic poles and the stator's pole teeth when pulses P[1] to P[8] are input to the stepper motor. Figures 11-18 The image schematically represents the rotor's magnetic poles and the stator. Figures 11-18 In order to easily grasp the positional relationship between the rotor 41 and the stator 60 (A-phase stator 61, B-phase stator 62), black circles are marked on the reference pole teeth 61a and the magnetic poles (S poles) of the reference rotor 41.

[0105] When pulses P are cyclically input to the stepper motor 66 in ascending order, and the rotor 41 rotates in the first direction, the rotor 41 and the valve shaft holder 42 move downwards due to the threaded feed action of the internal thread 42c of the valve shaft holder 42 and the external thread 43c of the guide bushing 43. The valve shaft holder 42 presses the valve core 30 downwards via the valve closing spring 47. The valve core 30 moves downwards, and the valve part 33 contacts the valve seat 18. At this time, the rotor 41 is in the closed position Rc. When the rotor 41 is rotated further in the first direction from this state, the valve closing spring 47 is compressed, and the rotor 41 and the valve shaft holder 42 move further downwards. The valve core 30 does not move downwards. Moreover, when the movable stop 42s of the valve shaft holder 42 contacts the fixed stop 44s of the stop member 44, the rotation of the rotor 41 in the first direction is restricted. At this time, the rotor 41 is in the reference position Rx. The movable stop 42s and the fixed stop 44s are stop mechanisms 49 that restrict the rotation of the rotor 41 in the first direction when the rotor 41 is in the reference position Rx.

[0106] When pulses P are cyclically input to the stepper motor 66 in descending order, and the rotor 41 moves in the second direction, the rotor 41 and the valve shaft holder 42 move upwards due to the threaded feed action of the internal thread 42c of the valve shaft holder 42 and the external thread 43c of the guide bushing 43. The valve shaft holder 42 presses the fixing member 45 upwards. The valve core 30 moves upwards together with the fixing member 45, thereby moving the valve core 30 away from the valve seat 18. Under a specified flow measurement environment, the position of the rotor 41 when the flow rate of the fluid in the valve port 17 (the opening degree of the valve port 17) is a specified set value is taken as the valve opening position Ro. The set value is appropriately set according to the configuration and purpose of the electric valve device 1. When the rotor 41 rotates in the second direction and reaches the fully open position Rz, the valve core 30 is furthest away from the valve port 17, and the valve port 17 is at its maximum opening.

[0107] The number of pulses P used to rotate rotor 41 from the fully open position Rz to the reference position Rx is called the stroke number Ns. That is, when a pulse P with a stroke number of Ns is input to the stepper motor 66 of the electric valve 5 with rotor 41 in the fully open position Rz, rotor 41 is positioned at the reference position Rx. For example, the stroke number Ns is 500. The number of pulses P used to rotate rotor 41 from the reference position Rx to the fully open position Rz is also the stroke number Ns.

[0108] The initialization number Ni is set based on the stroke number Ns. The initialization number Ni is the number of sufficient pulses P required to rotate the rotor 41 from the fully open position Rz to the reference position Rx. That is, even if the rotor 41 is in any position, when the pulse P of the initialization number Ni is input to the stepper motor 66, the rotor 41 is positioned at the reference position Rx. The initialization number Ni is, for example, 1.05 to 1.3 times the stroke number Ns. The initialization number Ni is used in the initialization operation to position the rotor 41 at the reference position Rx.

[0109] like Figure 7 As shown, 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 stepper motor 66 in a bipolar manner.

[0110] H-bridge circuit 77A is connected to phase A coil 61c. H-bridge circuit 77A has switches SW11, SW12, SW13, and SW14 as switching elements. H-bridge circuit 77B is connected to phase B coil 62c. H-bridge circuit 77B has switches SW21, SW22, SW23, and SW24 as switching elements. Switches SW11, SW12, SW13, and SW14, as well as switches SW21, SW22, SW23, and SW24, are, for example, N-channel MOSFETs or P-channel MOSFETs, or a combination of both.

[0111] Switches SW11, SW12, SW13, SW14 and switches SW21, SW22, SW23, SW24 are controlled to be on (conducting state) / off (non-conducting state).

[0112] The current control unit 77C controls the H-bridge circuits 77A and 77B by pulse width modulation based on the step signal and direction signal from the computer 80.

[0113] When the phase A current Ia flowing from terminal A1 to terminal A2 is supplied to phase A coil 61c: (1) The current control unit 77C sets switches SW12 and SW13 to open. (2) The current control unit 77C controls the on-time (i.e. duty cycle) of SW11 and SW14 in such a way that the magnitude of phase A current Ia is the same as the magnitude of the target value of phase A current Ita.

[0114] When the phase A current Ia flowing from terminal A2 to terminal A1 is supplied to phase A coil 61c: (1) The current control unit 77C sets switches SW11 and SW14 to open. (2) The current control unit 77C controls the on-time of switches SW12 and SW13 in such a way that the magnitude of phase A current Ia is the same as the magnitude of the target value of phase A current Ita.

[0115] When the B-phase current Ib flowing from terminal B1 to terminal B2 is supplied to the B-phase coil 62c: (1) The current control unit 77C sets switches SW22 and SW23 to be open. (2) The current control unit 77C controls the on-time of switches SW21 and SW24 in such a way that the magnitude of the B-phase current Ib is the same as the magnitude of the target value Itb of the B-phase current.

[0116] When the B-phase current Ib flowing from terminal B2 to terminal B1 is supplied to the B-phase coil 62c: (1) The current control unit 77C sets switches SW21 and SW24 to be open. (2) The current control unit 77C controls the on-time of switches SW22 and SW23 in such a way that the magnitude of the B-phase current Ib is the same as the magnitude of the target value Itb of the B-phase current.

[0117] The low-pass filter 78 is a circuit that includes resistors and capacitors. The low-pass filter 78 has an A-phase low-pass filter 78A and a B-phase low-pass filter 78B.

[0118] The input terminals of the A-phase low-pass filter 78A are connected to terminals A1 and A2 of the A-phase coil 61c, and the output terminal is connected to the computer 80. The A-phase low-pass filter 78A cuts off (including substantially cuts off) the voltage component with a frequency higher than the cutoff frequency Fc in the voltage VA generated between terminals A1 and A2 of the A-phase coil 61c, and allows the voltage component Vac with a frequency lower than the cutoff frequency Fc to pass through. The voltage component Vac is input to the computer 80.

[0119] The input terminals of the B-phase low-pass filter 78B are connected to terminals B1 and B2 of the B-phase coil 62c, and the output terminal is connected to the computer 80. The B-phase low-pass filter 78B cuts off (including substantially cuts off) the voltage component with a frequency higher than the cutoff frequency Fc in the voltage VB generated between terminals B1 and B2 of the B-phase coil 62c, and allows the voltage component Vbc with a frequency lower than the cutoff frequency Fc to pass through. The voltage component Vbc is input to the computer 80.

[0120] The cutoff frequency Fc is set to effectively cut off (attenuate) the voltage components generated by the A-phase current Ia in voltage VA and the voltage components generated by the B-phase current Ib in voltage VB within the low-pass filter 78. A smaller cutoff frequency Fc results in more effective cutoff of these voltage components, but also a larger time constant of the low-pass filter 78, thus increasing the waveform delay of voltage components Vac and Vbc. The allowable delay time caused by the low-pass filter 78 is set as the allowable delay time Td. Voltage component Vac mainly includes the voltage component generated by the rotation of rotor 41 (the voltage electromagnetically induced by the A-phase coil 61c). Voltage component Vbc mainly includes the voltage component generated by the rotation of rotor 41 (the voltage electromagnetically induced by the B-phase coil 62c).

[0121] In this embodiment, the PWM frequency is 20kHz and the cutoff frequency Fc is 1000Hz. The cutoff frequency Fc of the low-pass filter 78 is determined, for example, using the following equations (a) to (c).

[0122] Vout=Vin / (sRC+1)…(a)

[0123] Fc=1 / (2πCR)…(b)

[0124] Td≥RC…(c)

[0125] Where Vin is the input voltage, Vout is the output voltage, R is the resistance value of the resistor, C is the capacitance of the capacitor, and Td is the allowable delay time. Equation (a) is the transfer function of the low-pass filter 78. When ω is set as the angular velocity, s = jω, ω = 2πf. Within the range satisfying equations (a) to (c), the cutoff frequency Fc (i.e., the resistance value R and the capacitance C) is changed while the output voltage Vout (voltage components Vac and Vbc) is observed, and a cutoff frequency Fc that can effectively cut off the voltage component generated by the A-phase current Ia in voltage VA and the voltage component generated by the B-phase current Ib in voltage VB is selected. The cutoff frequency Fc is sufficiently lower than the PWM frequency. The cutoff frequency Fc is preferably less than one-tenth of the PWM frequency, and more preferably less than one-twentieth of the PWM frequency.

[0126] In addition, the low-pass filter 78 can also be composed of an operational amplifier or a digital signal processor.

[0127] Figure 19 This example shows the waveforms of the voltage VA generated in phase A coil 61c and the voltage VB generated in phase B coil 62c when pulses P are input to stepper motor 66 in ascending order. Figure 19 In the process, the A-phase current Ia and the B-phase current Ib are controlled by pulse width modulation. Therefore, the voltage VA oscillates with a large amount of short interval during the periods corresponding to pulses P[1], P[2], P[4], P[5], P[6], and P[8], and the voltage VB oscillates with a large amount of short interval during the periods corresponding to pulses P[2], P[3], P[4], P[6], P[7], and P[8]. Figure 20 Examples showing the waveforms of voltage component Vac in voltage VA and voltage component Vbc in voltage VB. Voltage components Vac and Vbc are voltage components with frequencies lower than the cutoff frequency Fc, passed through low-pass filter 78. Figure 20 As shown, by inputting voltages VA and VB into low-pass filter 78, the voltage components generated by phase A current Ia and phase B current Ib can be removed.

[0128] Computer 80 is a microcomputer that integrates a CPU, ROM, RAM, input / output interface, and A / D converter into a single packaged embedded device. Computer 80 may also include non-volatile memory 75, a communication device 76, and a motor driver 77. Computer 80 functions as a rotation control unit 81, an acquisition unit 82, and a decision unit 83 by executing programs stored in ROM through its CPU. Computer 80 is a processing device.

[0129] The rotation control unit 81 inputs a pulse P to the stepper motor 66, causing the rotor 41 to rotate in a first direction or a second direction. Specifically, the rotation control unit 81 controls the motor driver 77 based on commands from the air conditioning control device 110, supplying A-phase current Ia to the A-phase coil 61c and B-phase current Ib to the B-phase coil 62c. The rotation control unit 81 inputs a step signal, a direction signal, and a current control signal to the motor driver 77.

[0130] The acquisition unit 82 acquires the voltage component Vac in the voltage VA generated by the A-phase coil 61c and the voltage component Vbc in the voltage VB generated by the B-phase coil 62c. Furthermore, in the following description, "voltage component Vac and voltage component Vbc" will be simply referred to as "voltage component V".

[0131] Specifically, when the rotation control unit 81 supplies A-phase current Ia to A-phase coil 61c and B-phase current Ib to B-phase coil 62c based on pulse P[k] (k=1~8), the acquisition unit 82 acquires the voltage component V in a time sequence.

[0132] The acquisition unit 82 acquires the voltage component V sequentially over a predetermined sampling period from the start time to the end time of pulse P. For example, the period from the start time to the end time of pulse P is 8 ms, and the sampling period is 200 μs. For example, the acquisition unit 82 acquires the voltage component V 40 times corresponding to the input of one pulse P[k].

[0133] The voltage component V, acquired sequentially over time, is the waveform of the voltage component V. In this specification, "waveform" refers to the time variation of a physical quantity (voltage) at a fixed point. When visualizing a "waveform," it is represented as a coordinate plane with the physical quantity as the vertical axis and time as the horizontal axis. Additionally, "waveform" also includes non-visual content such as data tables stored in the RAM of the computer 80 and non-volatile memory 75 that associate physical quantity data with time data.

[0134] During the initialization process, the determination unit 83 determines the state of the electric valve 5 based on the voltage component V acquired by the acquisition unit 82. The electric valve 5 has a rotation-allowed state Sp and a rotation-limited state Sr. The rotation-allowed state Sp is a state in which the rotor 41 has not reached the reference position Rx, and rotation of the rotor 41 in the first direction is allowed. The rotation-limited state Sr is a state in which the rotor 41 has reached the reference position Rx, the movable stop 42s abuts against the fixed stop 44s, and rotation of the rotor 41 in the first direction is limited.

[0135] Figure 21 , Figure 22 This is an example of the waveform of the voltage component V when pulses P are input to the stepper motor 66 in ascending order. Figure 21 The waveform represents the electric valve 5 in the rotational permissible state Sp. Figure 22 The waveform represents the electric valve 5 in the rotation-limited state Sr.

[0136] Figure 23 This indicates the rotation angle of rotor 41 when pulses P are input to stepper motor 66 in ascending order. Figure 23In the diagram, the dark line (Sp) represents the rotation angle of electric valve 5 when it is in the rotation-allowed state (Sp), and the light line (Sr) represents the rotation angle of electric valve 5 when it is in the rotation-limited state (Sr). When electric valve 5 is in the rotation-allowed state (Sp), the rotation angle gradually increases in response to the input of pulses P[1] to P[8]. When electric valve 5 is in the rotation-limited state (Sr), the rotation angle does not change in response to the input of pulses P[1], P[2], P[7], and P[8], the rotation angle decreases significantly in response to the input of pulse P[3], and the rotation angle gradually increases in response to the input of pulses P[4], P[5], and P[6].

[0137] Figure 24 This example illustrates the waveform of the voltage component V when pulses P are input to stepper motor 66 in ascending order. Figure 24 In the diagram, the dark line (Sp) represents the voltage component V when the electric valve 5 is in the rotation-allowed state (Sp), and the light line (Sr) represents the voltage component V when the electric valve 5 is in the rotation-limited state (Sr). For example... Figure 24 As shown, the waveform of the voltage component V when the electric valve 5 is in the rotation-allowed state Sp is different from the waveform of the voltage component V when the electric valve 5 is in the rotation-limited state Sr. Specifically, it is different from the waveforms corresponding to pulses P[1]~P[4], P[7], and P[8], but roughly the same as the waveforms corresponding to pulses P[5] and P[6]. Therefore, by setting the waveform of the voltage component V when the electric valve 5 is in the rotation-allowed state Sp as the reference waveform of the voltage component V, and by comparing the reference waveform of the voltage component V with the waveform of the voltage component V acquired by the acquisition unit 82, it is possible to determine whether the electric valve 5 is in the rotation-allowed state Sp or the rotation-limited state Sr. In addition, the waveform of the voltage component V when the electric valve 5 is in the rotation-limited state Sr can also be set as the reference waveform of the voltage component V.

[0138] The determination unit 83 compares the waveform of the voltage component V acquired by the acquisition unit 82 with the reference waveform of the voltage component V to determine the state of the electric valve 5.

[0139] For each pulse P[1] to P[8], a reference waveform for the voltage component Vac is set. In the electric valve 5 in the rotational permissible state Sp, a reference waveform for the voltage component Vac is set based on the waveform of the voltage component Vac obtained when a drive current is supplied to the stator 60 in response to the input of the ascending pulses P[1] to P[8].

[0140] For each pulse P[1] to P[8], a reference waveform for voltage component Vbc is set. In the electric valve 5 in the rotational permissible state Sp, a reference waveform for voltage component Vbc is set based on the waveform of voltage component Vbc obtained when a drive current is supplied to the stator 60 in response to the input of the ascending pulses P[1] to P[8].

[0141] The reference waveform of the voltage component V is stored as a data table in non-volatile memory 75.

[0142] The reference waveform tables Ca[1] to Ca[8] are stored in the non-volatile memory 75. The reference waveform tables Ca[1] to Ca[8] are the reference waveforms of the voltage component Vac set by the pulses P[1] to P[8].

[0143] The reference waveform tables Cb[1] to Cb[8] are stored in the non-volatile memory 75. The reference waveform tables Cb[1] to Cb[8] are reference waveforms of the voltage component Vbc set by the pulses P[1] to P[8].

[0144] Figure 25 An example of a reference waveform table Ca[1]. In the data table, time t, which is a predetermined interval from the start time of pulse P (time 0), is associated with the reference voltage rv at that time t. The interval of time t is the same as the sampling period (200 μs) of the acquisition unit 82. A data table has 40 groups of time t and reference voltage rv. Figure 25 In this context, the unit of time t is μs. The unit of the reference voltage rv is mV. The units of time t and reference voltage rv may be, for example, units corresponding to the sampling period and resolution of the A / D converter of the electric valve control device 70, or they may be separate units.

[0145] The determination unit 83 calculates a difference index value, which represents the degree of difference between the waveform of the voltage component V acquired by the acquisition unit 82 and the reference waveform of the voltage component V. The larger the difference index value, the greater the degree of difference between the waveform of the voltage component V and the reference waveform of the voltage component V.

[0146] The determination unit 83 uses the voltage component Vac obtained corresponding to the input of the pulse P[k] and the reference waveform table Ca[k] to calculate the difference index value sva[k].

[0147] When the acquisition unit 82 acquires the voltage component Vac corresponding to the input of the pulse P[k] at the acquisition time tv, the determination unit 83 reads the reference voltage rv associated with the time t corresponding to the acquisition time tv from the reference waveform table Ca[k] corresponding to the pulse P[k]. The determination unit 83 calculates the value (dv) obtained by subtracting the reference voltage rv from the voltage component Vac acquired by the acquisition unit 82. The determination unit 83 calculates the value (dv) after squaring the difference value dv. 2 The determination unit 83 calculates multiple intermediate values ​​dv corresponding to the input pulse P[k]. 2 The difference index value sva[k] is calculated by adding them together.

[0148] The determination unit 83 uses the voltage component Vac acquired by the acquisition unit 82 during a portion of the period from the start time to the end time of pulse P[k] to calculate the difference index value sva[k]. Specifically, when the period from the start time of pulse P[k] to time t1 is defined as a first period p1, and the period from time t1 to time t2 is defined as a second period p2, the determination unit 83 uses the voltage component Vac of the second period p2 to calculate the difference index value sva[k]. The determination unit 83 does not use the voltage component Vac of the first period p1 in the calculation of the difference index value sva[k]. Time t1 is a time later than the start time of pulse P[k]. Time t2 is a time later than time t1 and earlier than the end time of pulse P[k]. Time t2 can also be the end time of pulse P[k].

[0149] After the pulse P[k] begins, the drive current is in a transitional state, and the voltages VA and VB are unstable. Therefore, after a certain amount of time has elapsed since the beginning of the pulse P[k], and the voltages VA and VB stabilize, the determination unit 83 calculates the difference index value sva[k] using the voltage component Vac acquired by the acquisition unit 82, thereby enabling a more accurate determination of the state of the electric valve 5.

[0150] Figure 26 This shows an example of the waveform of the voltage component Vac obtained corresponding to the input pulse P[k] and a reference waveform of the voltage component Vac. Figure 26 In the diagram, the waveform of the voltage component Vac is represented by a solid line (the acquired waveform), and the reference waveform of the voltage component Vac is represented by a dashed line. Figure 26 In the second period p2, the length of the vertical line connecting the voltage component Vac of the second period p2 and the reference waveform of the voltage component Vac corresponds to the difference value dv used to calculate the difference index value sva[k].

[0151] The length of the first period p1 is 5% to 50% of the period from the start time to the end time of pulse P[k], preferably 20% to 30%. The length of the second period p2 is 50% to 95% of the period from the start time to the end time of pulse P[k], preferably 70% to 80%. Alternatively, the determination unit 83 may use the voltage component Vac acquired by the acquisition unit 82 during the entire period from the start time to the end time of pulse P[k] to calculate the difference index value sva[k]. In this structure, the start time of pulse P[k] is time t1, and the end time of pulse P[k] is time t2.

[0152] The voltage component Vac acquired during the acquisition time tv from time t1 to time t2 is set as v[tv], and the reference voltage rv associated with the acquisition time t corresponding to the acquisition time tv in the reference waveform data table is set as rv[tv]. The difference index value sva is represented by the following mathematical formula (1).

[0153] [Mathematical Expression 1]

[0154]

[0155] Furthermore, the difference index value sva is not limited to the value calculated using the mathematical formula (1) described above. The difference index value sva can also be related to the magnitude shift of the voltage component Vac in the acquisition time tv, for example. Specifically, the electric valve control device 70 calculates the difference value dv between the voltage component Vac at the acquisition time tv corresponding to time t and the reference voltage rv associated with time t. The difference value dv is calculated as an absolute value. The electric valve control device 70 uses the number of difference values ​​dv calculated for the voltage component Vac acquired in the second period p2 that exceed a specified difference judgment value as the difference index value. Such a difference index value also appropriately reflects the degree of difference in the waveform shape.

[0156] Similar to the difference index value sva[k], the determination unit 83 uses the voltage component Vbc acquired corresponding to the input of pulse P[k] and the reference waveform table Cb[k] to calculate the difference index value svb[k]. Furthermore, in the following description, "difference index value sva and difference index value svb" will be simply referred to as "difference index value sv".

[0157] The determination unit 83 determines the state of the electric valve 5 based on the difference index value sv[k]. Specifically, the determination unit 83 compares the difference index value sv[k] with a predetermined difference determination value H. Based on the comparison result between the difference index value sv[k] and the difference determination value H, the determination unit 83 determines whether the electric valve 5 is in a rotation-allowed state Sp or a rotation-limited state Sr. In addition, the electric valve control device 70 may also have difference determination values ​​H[1] to H[8] corresponding to the difference index values ​​sv[1] to sv[8]. The difference determination values ​​H[1] to H[8] may be the same value or different values.

[0158] Next, refer to Figure 27 Example of initialization action of electric valve control device 70 (Action Example 1).

[0159] When an initialization command is received from the air conditioning control device 110 (S110), the electric valve control device 70 (computer 80) inputs pulses P[1] to P[8] in ascending order to the stepper motor 66 (S120). As a result, the initialization operation begins, and the stator 60 is supplied with a drive current corresponding to the pulses P[1] to P[8], and the rotor 41 rotates in the first direction.

[0160] When the rotor 41 rotates in the first direction, the electric valve control device 70 acquires the voltage component Vac in the voltage VA generated by the A-phase coil 61c and the voltage component Vbc in the voltage VB generated by the B-phase coil 62c in a time sequence (S130). That is, the electric valve control device 70 acquires the waveforms of the voltage component Vac and the voltage component Vbc. The electric valve control device 70 acquires the voltage components Vac and Vbc when it supplies drive current to the stator 60 according to the input of pulse P[k] (k=1~8).

[0161] The electric valve control device 70 calculates the difference index value sv (S140). Specifically, the electric valve control device 70 uses the reference waveform table Ca[k] to calculate the difference index value sva[k] corresponding to the input of pulse P[k]. The electric valve control device 70 uses the reference waveform table Cb[k] to calculate the difference index value svb[k] corresponding to the input of pulse P[k].

[0162] Up to the end of pulse P[k], the electric valve control device 70 determines the state of electric valve 5 based on the difference index value sv[k] (S150). In other words, before the next pulse P[j] of the input pulse P[k] (j=k+1 when k=1~7, j=1 when k=8), the electric valve control device 70 determines the state of electric valve 5 based on the difference index value sv[k]. Pulse P[k] is the pulse to be determined. Specifically, the electric valve control device 70 compares the difference index value sva[k] with the difference determination value H, and compares the difference index value svb[k] with the difference determination value H. When the difference index value sva[k] is greater than or equal to the difference determination value H and the difference index value svb[k] is greater than or equal to the difference determination value H, the electric valve control device 70 determines that electric valve 5 is in the rotation restriction state Sr. When the difference index value sva[k] is less than the difference judgment value H, or when the difference index value svb[k] is less than the difference judgment value H, the electric valve control device 70 determines that the electric valve 5 is in the rotational permissible state Sp. Alternatively, the electric valve control device 70 may also use only one of the difference index values ​​sva[k] and svb[k] to determine the state of the electric valve 5.

[0163] When the electric valve 5 is determined to be in the rotation restriction state Sr (S160: Yes), the electric valve control device 70 ends the input of pulse P to the stepper motor 66 and notifies the air conditioning control device 110 of the completion (success) of the initialization action (S170).

[0164] When the electric valve 5 is in the rotational allowable state Sp (S160: No), and the number of pulses P input to the stepper motor 66 exceeds the initialization number Ni (S180: Yes), the electric valve control device 70 ends the input of pulses P to the stepper motor 66 and notifies the air conditioning control device 110 of the completion (failure) of the initialization action (S190).

[0165] When the number of pulses P input to the stepper motor 66 is less than or equal to the initialization number Ni (S190: No), the electric valve control device 70 executes steps S130 to S180 again.

[0166] When the initialization is successful, rotor 41 is positioned at the reference position Rx.

[0167] In the above-described action example 1, the electric valve control device 70 calculates the difference index value sv[k] corresponding to the input pulse P[k], and determines the state of the electric valve 5 before the next pulse P[j] following the input pulse P[k]. The electric valve control device 70 uses the voltage component V acquired during a second period p2 (times t1 to t2) to calculate the difference index value sv[k]. This second period p2 is a portion of the period from the start time to the end time of pulse P[k].

[0168] For example, when time t2 is close to the end of pulse P[k], the electric valve control device 70 sometimes calculates the difference index value sv[k] during the input period of the next pulse P[j] after pulse P[k]. In this configuration, the electric valve control device 70 uses the difference index value sv[k] during the input period of the next pulse P[j] after pulse P[k] to determine whether the electric valve 5 is in the rotation restriction state Sr. (Refer to...) Figure 28 Examples 2 and 3 of the operation of this structure are explained.

[0169] In Operation Examples 2 and 3, when the electric valve control device 70 determines that the electric valve 5 is in the rotation restriction state Sr, the rotor 41 is positioned at the position where the electric valve 5 is in the rotation restriction state Sr (S165). In Operation Examples 2 and 3, the steps other than step S165 are the same as those in Operation Example 1. Step S165 in Operation Examples 2 and 3 will be explained.

[0170] In Action Example 2, when the electric valve 5 is determined to be in rotation-limited state Sr based on the difference index value sv[k] during the input of the next pulse P[j] after pulse P[k] (S160: Yes), the electric valve control device 70 inputs a pulse P[k] following pulse P[j] (S165). For example, when the electric valve 5 is determined to be in rotation-limited state Sr based on the difference index value sv[7] during the input of pulse P[8], the electric valve control device 70 inputs a pulse P[7] following pulse P[8]. As a result, the rotor 41 is positioned at the position corresponding to the pulse P[k] that causes the electric valve 5 to change from rotation-allowed state Sp to rotation-limited state Sr. Then, the electric valve control device 70 ends the input of pulse P to the stepper motor 66 and notifies the air conditioning control device 110 of the completion (success) of the initialization operation (S170).

[0171] In action example 3, when the electric valve 5 is determined to be in rotation-limited state Sr based on the difference index value sv[k] during the input of the pulse P[j] following the pulse P[k] (S160: Yes), the electric valve control device 70 inputs pulses P in ascending order following pulse P[j] until the input pulse P[k] (S165). For example, when the electric valve 5 is determined to be in rotation-limited state Sr based on the difference index value sv[7] during the input of pulse P[8], the electric valve control device 70 inputs pulses P[1] to P[7] following pulse P[8]. As a result, the rotor 41 is positioned at the position corresponding to the pulse P[k] that causes the electric valve 5 to change from rotation-allowed state Sp to rotation-limited state Sr. Then, the electric valve control device 70 ends the input of pulse P to the stepper motor 66 and notifies the air conditioning control device 110 of the completion (success) of the initialization operation (S170).

[0172] As described above, the electric valve device 1 includes an electric valve 5 and an electric valve control device 70. The electric valve 5 includes: a valve body 10 having a valve port 17; a stepper motor 66 having a rotor 41 and a stator 60; and a valve core 30 that moves relative to the valve port 17 when the rotor 41 rotates. The electric valve control device 70 includes a low-pass filter 78 and a computer 80. A-phase current Ia and B-phase current Ib, controlled by pulse width modulation (PWM), are supplied to the A-phase coil 61c and B-phase coil 62c of the stator 60 to rotate the rotor 41. The low-pass filter 78 has a cutoff frequency Fc lower than the PWM frequency used in the PWM method, allowing voltage components Vac (at frequencies lower than Fc) in the voltage VA generated in the A-phase coil 61c and Vbc (at frequencies lower than Fc) in the voltage VB generated in the B-phase coil 62c to pass through. Computer 80 uses the voltage components Vac and Vbc that have passed through low-pass filter 78 to determine whether electric valve 5 is in the rotation restriction state Sr where the rotation of rotor 41 is restricted.

[0173] In this way, the higher frequency voltage component generated by the A-phase current Ia can be removed from the voltage VA generated in the A-phase coil 61c, and the voltage component generated by the rotation of the rotor 41 can be suppressed from being hidden in the voltage component generated by the A-phase current Ia. Similarly, the higher frequency voltage component generated by the B-phase current Ib can be removed from the voltage VB generated in the B-phase coil 62c, and the voltage component generated by the rotation of the rotor 41 can be suppressed from being hidden in the voltage component generated by the B-phase current Ib. Therefore, even if the A-phase current Ia is supplied to the A-phase coil 61c, it is possible to determine whether the electric valve 5 is in a rotation-limited state Sr based on the voltage VA. Similarly, even if the B-phase current Ib is supplied to the B-phase coil 62c, it is possible to determine whether the electric valve 5 is in a rotation-limited state Sr based on the voltage VB. Thus, it is possible to determine at the appropriate time whether the rotation of the rotor 41 of the stepper motor 66 is limited.

[0174] Furthermore, the computer 80 of the electric valve control device 70 determines whether the electric valve 5 is in a rotation-limited state Sr based on the degree of difference between the waveform of voltage component Vac and the reference waveform of voltage component Vac, and the degree of difference between the waveform of voltage component Vbc and the reference waveform of voltage component Vbc. In this way, compared with the structure of the electric valve control device 70 that determines the state of electric valve 5 based on the area or maximum amplitude of the waveform, the state of electric valve 5 can be determined with higher accuracy.

[0175] Additionally, phase A coil 61c and phase B coil 62c are connected to motor driver 77. Multiple pulses P with consecutive numbers are sequentially and repeatedly input to motor driver 77. Motor driver 77 supplies phase A current Ia corresponding to the multiple pulses P to phase A coil 61c and phase B current Ib to phase B coil 62c, causing rotor 41 to rotate. Computer 80 begins inputting multiple pulses P to motor driver 77. When phase A current Ia corresponding to the pulse P[k] input to motor driver 77 is supplied to phase A coil 61c and phase B current Ib is supplied to phase B coil 62c, computer 80 acquires voltage components Vac and Vbc. Computer 80 uses voltage components Vac and Vbc to determine whether electric valve 5 is in a rotation-limited state Sr. When computer 80 determines that electric valve 5 is in a rotation-limited state Sr, it stops inputting multiple pulses P before the next pulse P[j] after input pulse P[k]. In this way, rotor 41 is positioned corresponding to the pulse P[k] that causes electric valve 5 to change from the rotation-allowed state Sp to the rotation-limited state Sr. Therefore, rotor 41 can be positioned more accurately at the reference position Rx.

[0176] Furthermore, in the structure where the computer 80 uses voltage components Vac and Vbc to determine whether the electric valve 5 is in a rotation-limited state Sr during the input of the next pulse P[j] after pulse P[k], the computer 80 can also operate as follows: When it is determined that the electric valve 5 is in a rotation-limited state Sr, the computer 80 inputs pulse P[k] to the motor driver 77 following pulse P[j], and then stops inputting multiple pulses P. Alternatively, when it is determined that the electric valve 5 is in a rotation-limited state Sr, the computer 80 inputs pulses P to the motor driver 77 in ascending order following pulse P[j] until pulse P[k] is input to the motor driver 77, and then stops inputting multiple pulses P. In this way, even in this structure, the rotor 41 is positioned at the position corresponding to the pulse P[k] that causes the electric valve 5 to change from a rotation-allowed state Sp to a rotation-limited state Sr. Therefore, the rotor 41 can be positioned more accurately at the reference position Rx.

[0177] In the aforementioned electric valve device 1, the electric valve control device 70 drives the stepper motor 66 in a half-step mode. The electric valve control device 70 can also drive the stepper motor 66 in micro-step modes 1 and 2. The electric valve control device 70 can also drive the stepper motor 66 in a full-step mode. In the half-step mode, the drive current has three levels (I2, I1, 0). In micro-step mode 1, the drive current has five levels. In micro-step mode 2, the drive current has nine levels.

[0178] Figure 29 , Figure 30This represents the rotation angle of rotor 41 and voltage components V (voltage component Vac, voltage component Vbc) when the stepper motor 66 is driven in micro-stepping mode 1. Figure 31 , Figure 32 This represents the rotation angle of rotor 41 and the voltage components V (voltage component Vac, voltage component Vbc) when the stepper motor 66 is driven in micro-stepping mode 2. Figure 29 , Figure 31 In the diagram, the horizontal axis represents time, and the vertical axis represents the rotation angle. Figure 30 , Figure 32 In the diagram, the horizontal axis represents time, and the vertical axis represents voltage.

[0179] Figure 29 , Figure 31 This indicates the rotation angle of rotor 41 when pulses P are input to stepper motor 66 in ascending order. Figure 29 , Figure 31 In the diagram, the dark line (Sp) represents the rotation angle of the electric valve 5 when it is in the rotation-allowed state Sp, and the light line (Sr) represents the rotation angle of the electric valve 5 when it is in the rotation-limited state Sr.

[0180] Figure 30 , Figure 32 This is an example showing the waveform of the voltage component V when pulses P are input to stepper motor 66 in ascending order. Figure 30 , Figure 32 In the diagram, the dark line (Sp) represents the voltage component V when the electric valve 5 is in the rotational allowable state Sp, and the light line (Sr) represents the voltage component V when the electric valve 5 is in the rotational restricted state Sr.

[0181] Even in a structure where the stepper motor 66 is driven in a micro-stepping manner, it achieves the same (essentially the same) effect as a structure driven in a half-stepping manner.

[0182] In this specification, terms such as "cylinder" and "cylindrical" that indicate shape are also used for parts or portions of parts that substantially have the shape described by these terms. For example, "cylindrical-shaped part" includes both cylindrical-shaped parts and substantially cylindrical-shaped parts. Additionally, in this specification, the term "identical" sometimes includes cases of strict similarity and cases of substantial similarity.

[0183] The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Any additions, deletions, design changes, or appropriate combinations of features of the embodiments made by those skilled in the art to the above embodiments, as long as they do not violate the spirit of the present invention, are included within the scope of the present invention.

[0184] Symbol Explanation

[0185] 1…Electric valve device, 5…Electric valve, 10…Valve body, 11…Main body component, 11a…Matching hole, 11b…Through hole, 11d…Plane, 13…Connecting component, 14…Valve chamber, 15…First conduit, 16…Second conduit, 17…Valve port, 18…Valve seat, 20…Housing, 30…Valve core, 31…First shaft, 32…Second shaft, 33…Valve part, 34…Stepped part, 40…Drive mechanism, 41…Rotor, 41 a…Matching hole, 42…Valve shaft retainer, 42a…Upper wall, 42b…Shaft hole, 42c…Internal thread, 42s…Modible stop, 43…Guide bushing, 43a…Base, 43b…Support, 43c…External thread, 43d…Flat surface, 44…Stop component, 44a…Stop body, 44c…Internal thread, 44s…Fixed stop, 45…Fixed component, 45a…Fixed part, 45b…Flange, 46…Washer, 4 7…valve closing spring, 48…return spring, 49…stopping mechanism, 60…stator, 61…A-phase stator, 61a…pole tooth, 61b…pole tooth, 61c…A-phase coil, 62…B-phase stator, 62a…pole tooth, 62b…pole tooth, 62c…B-phase coil, 66…stepper motor, 70…electric valve control device, 71…board, 75…non-volatile memory, 76…communication device, 77…motor driver, 77A…H-bridge circuit 77B…H-bridge circuit, 77C…current control unit, 78…low-pass filter, 78A…A-phase low-pass filter, 78B…B-phase low-pass filter, 80…computer, 81…rotation control unit, 82…acquisition unit, 83…determination unit, 100…air conditioning system, 101…compressor, 102…condenser, 103…evaporator, 105…piping, 110…air conditioning control device, 120…wired communication bus, L…axis.

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; and a valve core that moves relative to the valve port when the rotor rotates, characterized in that, The electric valve control device includes a low-pass filter and a processing unit. A drive current, controlled by pulse width modulation, is supplied to the coils of the stator to rotate the rotor. The low-pass filter has a cutoff frequency lower than the pulse width modulation frequency used in the pulse width modulation method, and the low-pass filter allows voltage components in the voltage generated by the coil that have frequencies lower than the cutoff frequency to pass through. The processing device uses the voltage component that has passed through the low-pass filter to determine whether the electric valve is in a rotation-limited state where the rotation of the rotor is restricted.

2. The electric valve control device according to claim 1, characterized in that, The processing device determines whether the electric valve is in the rotation restriction state based on the degree of difference between the waveform of the voltage component and the reference waveform of the voltage component.

3. The electric valve control device according to claim 1 or 2, characterized in that, The coil is connected to the motor driver. When a series of sequentially numbered pulses are repeatedly input to the motor driver, the motor driver supplies the drive current corresponding to the pulses to the coil, causing the rotor to rotate. The processing device begins to input the plurality of pulses to the motor driver. When the driving current corresponding to the pulse input to the motor driver is supplied to the coil, the processing device acquires the voltage component. The pulse input to the motor driver is referred to as the determination target pulse, and this voltage component is used to determine whether the electric valve is in the rotation restriction state. When the electric valve is determined to be in the rotation-limited state, the processing device stops the input of the plurality of pulses before inputting the next pulse of the pulse to be determined.

4. The electric valve control device according to claim 1 or 2, characterized in that, The coil is connected to the motor driver. When a series of sequentially numbered pulses are repeatedly input to the motor driver, the motor driver supplies the drive current corresponding to the pulses to the coil, causing the rotor to rotate. The processing device begins to input the plurality of pulses to the motor driver. When the drive current corresponding to the pulse input to the motor driver is supplied to the coil, the processing device acquires the voltage component. The pulse input to the motor driver is referred to as the determination target pulse, and the processing device uses this voltage component during the input of the next pulse of the determination target pulse to determine whether the electric valve is in the rotation restriction state. When the electric valve is determined to be in the rotation restriction state, the processing device inputs a pulse with the same number as the determined pulse to the motor driver following the next pulse of the determined pulse, and stops the input of the plurality of pulses.

5. The electric valve control device according to claim 1 or 2, characterized in that, The coil is connected to the motor driver. When a series of sequentially numbered pulses are repeatedly input to the motor driver, the motor driver supplies the drive current corresponding to the pulses to the coil, causing the rotor to rotate. The processing device begins to input the plurality of pulses to the motor driver. When the drive current corresponding to the pulse input to the motor driver is supplied to the coil, the processing device acquires the voltage component. The pulse input to the motor driver is referred to as the determination target pulse, and the processing device uses this voltage component during the input of the next pulse of the determination target pulse to determine whether the electric valve is in the rotation restriction state. When the electric valve is determined to be in the rotation restriction state, the processing device sequentially inputs the plurality of pulses to the motor driver following the next pulse of the determination target pulse, until a pulse with the same number as the determination target pulse is input to the motor driver, and then stops inputting the plurality of pulses.

6. The electric valve control device according to claim 1 or 2, characterized in that, The cutoff frequency is set based on the pulse width modulation frequency.

7. An electric valve device, characterized in that, have: The electric valve control device according to claim 1; and the electric valve.

8. A method for determining the state of an electric valve, the electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator; and a valve core that moves relative to the valve port when the rotor rotates, characterized in that... A drive current, controlled by pulse width modulation, is supplied to the coils of the stator to rotate the rotor. The voltage generated in the coil is input to a low-pass filter, which has a cutoff frequency lower than the pulse width modulation frequency used in the pulse width modulation method, and the low-pass filter allows voltage components in the voltage generated in the coil that have frequencies lower than the cutoff frequency to pass through. The voltage component that has passed through the low-pass filter is used to determine whether the electric valve is in a rotation-limited state where the rotor's rotation is restricted.

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