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

Abstract

[Problem] To provide a motorized valve control device, a motorized valve device, and a motorized valve control method with a simple configuration capable of estimating the temperature of a rotor of a stepping motor with high accuracy. [Solution] A stepping motor 66 of a motorized valve includes a rotor 41 and a stator 60 provided with a coil. A computer 80 of a motorized valve control device estimates the temperature of the rotor 41 on the basis of a current flowing through the coil, and supplies, to the coil, a drive current with a magnitude corresponding to the temperature of the rotor 41.

Description

Technical Field

[0006] , ,

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

Background Art

[0002] Patent Document 1 describes an example of a conventional electric valve. For example, the electric valve is incorporated into a refrigeration cycle system of an air conditioner and used as a flow control valve for controlling the flow rate of a refrigerant. The electric valve has a valve body, a valve element, and a stepping motor. The stepping motor has a rotor and a stator. The rotor is disposed inside a can that is a case joined to the valve body. The rotor has a plurality of magnetic poles. The stator is disposed outside the can. The stator has a coil. The electric valve is controlled by an electric valve control device. When the electric valve control device supplies a drive current to the coil of the stator, the rotor rotates. The valve element moves in response to the rotation of the rotor.

Prior Art Documents

[0007] The electric valve control unit has a circuit board and a temperature sensor mounted on the circuit board. The electric valve control unit estimates the rotor temperature based on the temperature sensor signal and controls the magnitude of the drive current according to the rotor temperature, thereby suppressing excessive power consumption by the stepping motor. However, because the temperature sensor mounted on the circuit board is far from the can, it is difficult for the electric valve control unit to estimate the rotor temperature with high accuracy. Placing the temperature sensor on the can to estimate the rotor temperature with high accuracy complicates the configuration of the electric valve control unit.

[0008] Therefore, the present invention aims to provide an electric valve control device and electric valve device with a simple configuration that can estimate the rotor temperature with high accuracy, as well as a method for controlling an electric valve. [Means for solving the problem]

[0009] The inventors used multiple electric valves to supply current to the stator coils and measured the current flowing through the coils, then diligently studied the measurement results. As a result, the inventors discovered that the current flowing through the coils is related to the rotor temperature, leading to the present invention.

[0010] To achieve the above objective, an electric valve control device according to one aspect of the present invention is an electric valve control device that controls an electric valve to which a drive current for rotating the rotor is supplied to the coil, the electric valve control device having a valve body having a valve chamber and a valve port, a cylindrical case attached to the valve body and having an inner space connected to the valve chamber, a rotor disposed in the inner space, a stator having a hollow annular yoke in contact with the outer circumferential surface of the case and a coil housed in the yoke, and a valve body facing the valve port in the valve chamber and moving relative to the valve port when the rotor rotates, the electric valve control device having a processing device for estimating the temperature of the rotor based on the current flowing through the coil.

[0011] In the present invention, it is preferable that the drive current is a current that alternately changes between a first current value and a second current value, and that the processing device estimates the temperature of the rotor using information relating to the change period from the first current value to the second current value in which the current flowing through the coil changes.

[0012] In the present invention, it is preferable that the information relating to the change period is the change time from the start to the end of the change period.

[0013] In the present invention, it is preferable that the current is controlled by a pulse width modulation scheme, and the information relating to the change period is the duty cycle of the pulse width modulation scheme during the determination period including the change period.

[0014] In the present invention, it is preferable that the information relating to the change period is the degree of difference between the waveform of the current flowing through the coil and the reference waveform of the current during the determination period including the change period.

[0015] In the present invention, it is preferable that the information relating to the change period is the slope of the waveform of the current flowing through the coil during the change period.

[0016] In the present invention, it is preferable that the coil is connected to a current supply device, and the processing device controls the current supply device so that a drive current of an magnitude corresponding to the temperature of the rotor is supplied to the coil.

[0017] In the present invention, it is preferable that the coil is connected to a current supply device, and the processing device controls the current supply device so that when the temperature of the rotor is lower than the operating temperature determination value, a current is supplied to the coil to raise the temperature of the rotor.

[0018] In the present invention, it is preferable that the electric valve is incorporated into a refrigeration cycle system and used to control the flow rate of the refrigerant, and that the processing device estimates the temperature of the rotor after a waiting period has elapsed since the refrigeration cycle system stopped, and that the waiting period is set to a length of time at which the temperature difference between the rotor and the coil disappears.

[0019] In the present invention, it is preferable that the coil is connected to a current supply device, the electric valve control device has a temperature sensor that outputs a signal corresponding to the temperature of the space in which the stator is located, the processing device estimates the temperature of the rotor based on the current flowing through the coil and obtains the temperature of the space from the signal, controls the current supply device so that a normal-sized drive current is supplied to the coil when the temperature of the rotor is higher than the rotor temperature determination value or the temperature of the space is higher than the space temperature determination value, and controls the current supply device so that a larger-than-normal-sized drive current is supplied to the coil when the temperature of the rotor is less than or equal to the rotor temperature determination value and the temperature of the space is less than or equal to the space temperature determination value.

[0020] In the present invention, it is preferable that the electric valve has a housing that accommodates the stator and the temperature sensor.

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

[0022] In order to achieve the above object, a method for controlling an electric valve according to another aspect of the present invention includes a valve body having a valve chamber and a valve port, a cylindrical case attached to the valve body and having an inner space connected to the valve chamber, a rotor disposed in the inner space, a stator having a hollow annular yoke in contact with the outer peripheral surface of the case and a coil accommodated in the yoke, and a valve body facing the valve port in the valve chamber and moving relative to the valve port when the rotor rotates. A method for controlling an electric valve in which a drive current for rotating the rotor is supplied to the coil, the method estimating the temperature of the rotor based on the current flowing through the coil and supplying the drive current having a magnitude corresponding to the temperature of the rotor to the coil.

Advantages of the Invention

[0023] According to the present invention, the valve chamber and the inner space of the case are connected, and the fluid in the valve chamber is introduced into the inner space of the case. The temperature of the fluid is reflected in the temperature of the rotor and also in the temperature of the coil via the case and the yoke. The temperature of the coil and the temperature of the rotor are related, and the current flowing through the coil is related to the temperature of the rotor. The temperature of the rotor is estimated based on the current flowing through the coil of the stator. Thus, the temperature of the rotor can be estimated with high accuracy using an electric valve control device having a simple configuration.

Brief Description of the Drawings

[0024] [Figure 1] It is a block diagram of an air conditioner having an electric valve device. [Figure 2] It is a cross-sectional view of the electric valve device. [Figure 3] It is a plan view of a valve shaft holder, a movable stopper, a fixed stopper, a rotor, and a stator of the electric valve device. [Figure 4] It is a diagram schematically showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[1] is input). [Figure 5]This diagram schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when pulse P[2] is input). [Figure 6] This diagram schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when pulse P[3] is input). [Figure 7] This diagram schematically shows the positional relationship between the rotor's magnetic poles and the stator's pole teeth (when pulse P[4] is input). [Figure 8] This diagram schematically shows the computer, motor driver, and stepping motor of the electric valve control unit of an electric valve device. [Figure 9] This figure shows an example of the relationship between the pulses input to a stepping motor and the step and direction signals input to the motor driver. [Figure 10] This figure shows an example of the correspondence between pulses and the target values ​​for phase A and phase B currents. [Figure 11] This diagram schematically shows examples of the waveforms of the A-phase current and the B-phase current. [Figure 12] This figure shows an example of the waveform of the drive current flowing through the stator coil. [Figure 13] This figure shows another example of the waveform of the drive current flowing through the stator coil. [Figure 14] This figure shows an example of the relationship between the rotor's rotation direction, rotor temperature, power supply voltage, and rise time. [Figure 15] This diagram schematically shows the waveform of the drive current flowing through the stator coil. [Figure 16] This diagram schematically shows an example of the relationship between the drive current waveform and the duty cycle (when the rotor temperature is low). [Figure 17] This diagram schematically illustrates another example of the relationship between the drive current waveform and the duty cycle. (Under high rotor temperature conditions) [Figure 18] This diagram schematically shows the waveforms of the two drive currents. [Figure 19] This figure shows an example of the relationship between rotor temperature and target drive current. [Figure 20] This flowchart shows the first example of operation of the electric valve control device. [Figure 21] This flowchart shows a second example of operation for the electric valve control device. [Figure 22] This flowchart shows a third example of operation for the electric valve control device. [Figure 23] This is a flowchart showing the fourth example of operation of the electric valve control device. [Figure 24] This figure shows an example of a data table for the reference waveform of the drive current. [Modes for carrying out the invention]

[0025] The following describes an electric valve device according to one embodiment of the present invention.

[0026] The electric valve device 1 according to this embodiment is incorporated into, for example, the refrigeration cycle system of an air conditioner and used as a flow control valve to control the flow rate of refrigerant. The electric valve device 1 comprises an electric valve 5 and an electric valve control device 70. Figure 1 shows a block diagram of an air conditioner 100 having the electric valve device 1. Figure 2 shows a cross-sectional view of the electric valve device 1.

[0027] The air conditioner 100 has a compressor 101, a condenser 102, an electric valve device 1 (electric valve 5), and an evaporator 103 connected in order via piping 105. The electric valve device 1 is an expansion valve. The air conditioner 100 has an air conditioner control device 110. The air conditioner control device 110 is communicatively connected to the electric valve device 1 (electric valve control device 70). The air conditioner control device 110 controls the flow rate of refrigerant flowing through piping 105 using the electric valve device 1.

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

[0029] The valve body 10 comprises a main body member 11 and a connecting member 13. The main body member 11 has a cylindrical shape. The main body member 11 has a valve chamber 14 and a valve opening 17 connected to the valve chamber 14. A first conduit 15 and a second conduit 16 are joined to the main body member 11. The first conduit 15 is connected to the valve chamber 14. The second conduit 16 is connected to the valve opening 17. The main body member 11 has an annular valve seat 18 surrounding the valve opening 17 in the valve chamber 14. The main body member 11 has a circular fitting hole 11a. The fitting hole 11a is located on the upper end surface of the main body member 11. A through hole 11b 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 is joined to the upper end of the main body member 11. The main body component 11 and the connecting component 13 are made of metal such as aluminum alloy, stainless steel, or brass.

[0030] The can 20 is made of a metal such as stainless steel. The can 20 has a cylindrical shape. The can 20 is open at the bottom and closed at the top. The bottom end of the can 20 is joined to the outer edge of the connecting member 13. The inner space 21 of the can 20 is connected to the valve chamber 14. Refrigerant is introduced into the inner space 21 of the can 20. The can 20 is a case attached to the valve body 10.

[0031] The valve body 30 has a first shaft portion 31, a second shaft portion 32, and a valve portion 33. The first shaft portion 31 and the second shaft portion 32 have a cylindrical shape. The diameter of the second shaft portion 32 is smaller than the diameter of the first shaft portion 31. The second shaft portion 32 is coaxially connected to the upper end of the first shaft portion 31. The valve body 30 has a stepped portion 34, which is an annular plane facing upward. The stepped portion 34 is located at the connection point between the first shaft portion 31 and the second shaft portion 32. The valve portion 33 has a conical shape, with its diameter decreasing from top to bottom. The valve portion 33 is coaxially connected to the lower end of the first shaft portion 31. The valve portion 33 is located in the valve port 17. A variable throttling portion is formed between the valve portion 33 and the valve port 17. The valve portion 33 faces the valve port 17 and the valve seat 18. When the valve portion 33 contacts the valve seat 18, the valve opening 17 closes. When the valve portion 33 moves away from the valve seat 18, the valve opening 17 opens.

[0032] The drive mechanism 40 moves the valve body 30 in the vertical direction (axis L direction). The movement of the valve body 30 opens and closes the valve port 17. The drive mechanism 40 includes a rotor 41, a valve stem holder 42, a movable stopper 42s, a guide bush 43, a stopper member 44, a fixed stopper 44s, a retaining member 45, a washer 46, a valve closing spring 47, and a return spring 48.

[0033] Figure 3 shows a plan view of the rotor 41, valve stem holder 42, movable stopper 42s, fixed stopper 44s, and stator 60. In Figure 3, the magnetic poles of the rotor 41 and the stator 60 are schematically shown. In Figure 3, the radially outward direction of the figure shown as the stator 60 corresponds to the top of the stator 60, and the radially inward direction corresponds to the bottom.

[0034] The rotor 41 has a cylindrical shape. The outer diameter of the rotor 41 is slightly smaller than the inner diameter of the can 20. The rotor 41 is positioned inside the can 20. The rotor 41 is rotatable relative to the valve body 10. The rotor 41 has multiple magnetic poles (multiple north poles and multiple south poles). The multiple north poles and multiple south poles are arranged on the outer circumferential surface of the rotor 41. The multiple north poles and multiple south poles extend in the vertical direction. The multiple north poles and multiple south poles are arranged alternately at equal angular intervals in the circumferential direction. For example, the rotor 41 has 12 north poles and 12 south poles. The angle between adjacent north poles and south poles is 15 degrees. The position of the rotor 41 is related to the opening degree of the valve port 17.

[0035] The valve stem holder 42 has a cylindrical shape. The lower end of the valve stem holder 42 is open. The valve stem holder 42 has an upper wall portion 42a with a shaft hole 42b. The valve stem holder 42 is fitted into the fitting hole 41a of the rotor 41 and rotates together with the rotor 41. A movable stopper 42s is integrally provided on the outer circumferential surface of the valve stem holder 42. The second shaft portion 32 of the valve body 30 is positioned in the shaft hole 42b, and the second shaft portion 32 is movable vertically within the shaft hole 42b. A valve closing spring 47 is positioned between a washer 46 positioned on the lower surface of the upper wall portion 42a of the valve stem holder 42 and the stepped portion 34 of the valve body 30. The valve closing spring 47 is a coil spring and pushes the valve body 30 toward the valve seat 18. An internal thread 42c is provided on the inner circumferential surface of the valve stem holder 42. The movable stopper 42s is fixed to the rotor 41.

[0036] The guide bush 43 has a base portion 43a and a support portion 43b. The base portion 43a and the support portion 43b have a cylindrical shape. The base portion 43a is press-fitted into the fitting hole 11a of the main body member 11. The support portion 43b is coaxially connected to the upper end of the base portion 43a. A male thread 43c is provided on the outer circumferential surface of the support portion 43b. The male thread 43c is screwed into the female thread 42c of the valve stem holder 42. The first shaft portion 31 of the valve body 30 is positioned inside the guide bush 43. The guide bush 43 supports the valve body 30 so that it can move in the axial direction L.

[0037] The stopper member 44 has a cylindrical shape. The stopper member 44 is fixed to the lower end of the support portion 43b of the guide bush 43. A fixed stopper 44s is integrally provided on the outer circumferential surface of the stopper member 44. The fixed stopper 44s is fixed to the valve body 10.

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

[0039] The electric valve 5 has a drive mechanism 40 that uses the rotor 41 without reducing its rotation speed. Alternatively, the electric valve 5 may have a drive mechanism that has a reduction mechanism for reducing the rotation speed of the rotor 41 instead of the drive mechanism 40.

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

[0041] The A-phase stack 61 has a hollow, annular yoke, and multiple claw-pole type pole teeth 61a and 61b are arranged on the inner circumference of the yoke. The tips of the pole teeth 61a point downward, and the tips of the pole teeth 61b point upward. 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 angle between adjacent pole teeth 61a and pole teeth 61b is 15 degrees. The A-phase stack 61 has an A-phase coil 61c. The A-phase coil 61c is wound on a cylindrical bobbin and is housed in the yoke together with the bobbin. The A-phase coil 61c is indirectly in contact with the yoke via the bobbin. However, the A-phase coil 61c may be in direct contact with the yoke as long as it is electrically insulated from the yoke. When the A-phase coil 61c is energized, the pole teeth 61a and 61b become magnetic poles with opposite polarities.

[0042] The B-phase stack 62 has a hollow, annular yoke, and multiple claw-pole type pole teeth 62a and 62b are arranged on the inner circumference of the yoke. The tips of the pole teeth 62a point downward, and the tips of the pole teeth 62b point upward. 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 angle between adjacent pole teeth 62a and pole teeth 62b is 15 degrees. The B-phase stack 62 has a B-phase coil 62c. The B-phase coil 62c is wound on a cylindrical bobbin and is housed in the yoke together with the bobbin. The B-phase coil 62c is indirectly in contact with the yoke via the bobbin. However, the B-phase coil 62c may be in direct contact with the yoke if it is electrically insulated from the yoke. 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 configuration as the A-phase stack 61.

[0043] The A-phase stack 61 is coaxially positioned on top of the B-phase stack 62. The B-phase stack 62 is positioned 7.5 degrees around axis L relative to the A-phase stack 61 from a position where the pole teeth 61a and pole teeth 62a are aligned in the direction of axis L.

[0044] A can 20 is positioned inside the stator 60, with the yokes of the A-phase stack 61 and the B-phase stack 62 in contact with the outer surface of the can 20. A rotor 41 is positioned inside the can 20. The stator 60 and rotor 41 are a stepping motor 66. The stepping motor 66 is connected to an electric valve control device 70.

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

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

[0047] Figures 4 to 7 schematically show the positional relationship between the magnetic poles of the rotor 41 and the pole teeth of the stator 60 when pulses P[1] to P[4] are input to the stepping motor 66. In Figures 4 to 7, the magnetic poles of the rotor 41 and the stator 60 are schematically shown. In Figures 4 to 7, black circles are placed on the reference pole teeth 61a and the reference magnetic pole (S pole) of the rotor 41 to make it easier to understand the positional relationship between the rotor 41 and the stator 60 (A-phase stack 61 and B-phase stack 62).

[0048] When pulses P are input cyclically in ascending order to the stepping motor 66, and the rotor 41 rotates in the first direction, the rotor 41 and the valve stem holder 42 move downward due to the feed screw action between the female thread 42c of the valve stem holder 42 and the male thread 43c of the guide bush 43. The valve stem holder 42 pushes the valve body 30 downward via the valve closing spring 47. The valve body 30 moves downward and the valve portion 33 contacts the valve seat 18. At this time, the position of the rotor 41 is the closed valve position Rc. If 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 stem holder 42 move further downward. The valve body 30 does not move downward. Then, when the movable stopper 42s contacts the fixed stopper 44s, the rotation of the rotor 41 in the first direction is restricted. At this time, the position of the rotor 41 is the reference position Rx. The movable stopper 42s and the fixed stopper 44s constitute a stopper mechanism 49 that restricts the rotation of the rotor 41 in the first direction when the rotor 41 is in the reference position Rx.

[0049] When pulses P are input cyclically in descending order to the stepping motor 66, and the rotor 41 rotates in the second direction, the rotor 41 and the valve stem holder 42 move upward due to the feed screw action between the female thread 42c of the valve stem holder 42 and the male thread 43c of the guide bush 43. The valve stem holder 42 pushes the retaining member 45 upward. The valve body 30 moves upward together with the retaining member 45, and the valve body 30 moves away from the valve seat 18. The position of the rotor 41 when the fluid flow rate at the valve port 17 (opening degree of the valve port 17) is a predetermined set value in a predetermined flow rate measurement environment is defined as the open valve position Ro. The set value is appropriately set according to the configuration and application of the electric valve device 1. When the rotor 41 rotates in the second direction and reaches the fully open position Rz, the valve body 30 is furthest away from the valve port 17, and the valve port 17 is at its maximum opening degree.

[0050] The number of pulses P required to rotate the rotor 41 from the fully open position Rz to the reference position Rx is called the stroke number Ns. That is, when pulses P with stroke number Ns are input to the stepping motor 66 of the electric valve 5, which is in the fully open position Rz, the rotor 41 moves to the reference position Rx. The stroke number Ns is, for example, 500.

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

[0052] The electric valve control device 70 has a circuit board 71 on which several electronic components (not shown) are mounted. As shown in Figure 1, 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 from the air conditioner control device 110.

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

[0054] The communication device 76 is connected to the air conditioner control device 110 via a wired communication bus 120 so as to be able to communicate. The air conditioner 100 employs a communication method such as Local Interconnect Network (LIN) or Controller Area Network (CAN). The communication device 76 may also be connected to the air conditioner control device 110 so as to be able to communicate wirelessly.

[0055] Figure 8 is a schematic diagram showing the computer 80, motor driver 77, and stepping motor 66 of the electric valve control device 70. The motor driver 77 is connected to the A-phase coil 61c and B-phase coil 62c of the stepping motor 66. The motor driver 77 is connected to the computer 80.

[0056] The motor driver 77 is controlled by the computer 80. The motor driver 77 supplies drive current (A-phase current Ia, B-phase current Ib) to the stator 60 to rotate the rotor 41. The motor driver 77 supplies A-phase current Ia to the A-phase coil 61c and B-phase current Ib to the B-phase coil 62c. The motor driver 77 is a current supply device.

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

[0058] Furthermore, the motor driver 77 receives a current control signal (CONTROL) from the computer 80. The current control signal is a signal to set the motor driver 77 to the target values ​​of the A-phase current Ia and B-phase current Ib, which are the target values ​​of the A-phase current Ia and B-phase current Ib.

[0059] Figure 10 shows an example of the correspondence between pulse P and the target values ​​for phase A and phase B currents. For pulse P[1], "+It" is set as the A-phase current target value and "-It" is set as the B-phase current target value. For pulse P[2], "+It" is set as the A-phase current target value and "+It" is set as the B-phase current target value. For pulse P[3], "-It" is set as the A-phase current target value and "+It" is set as the B-phase current target value. For pulse P[4], "-It" is set as the A-phase current target value and "-It" is set as the B-phase current target value. "+It" and "-It" represent currents of the same magnitude but with different directions. The target value (It) is, for example, 200-600mA.

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

[0061] In Figures 10 and 11, the signs (+ / -) indicate the direction of current flow. "+" indicates the direction from terminal A1 to terminal A2, or from terminal B1 to terminal B2. "-" indicates the direction from terminal A2 to terminal A1, or from terminal B2 to terminal B1.

[0062] In this embodiment, the period of pulse P is 8 ms, and one period including pulses P[1] to P[4] is 32 ms. The stepping motor 66 is controlled in a full-step manner. The step angle of the stepping motor 66 is 7.5 degrees. The stepping motor 66 may also be controlled in a half-step manner or a micro-step manner.

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

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

[0065] Switches SW11, SW12, SW13, SW14 and switches SW21, SW22, SW23, SW24 are controlled to be either on (conductive) or off (non-conductive).

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

[0067] When supplying the A-phase current Ia flowing from terminal A1 to terminal A2 to the A-phase coil 61c: (1) The current control unit 77C turns off switches SW12 and SW13. (2) The current control unit 77C controls the on time (i.e., duty cycle) of switches SW11 and SW14 so that the magnitude of the A-phase current Ia is the same as the magnitude of the A-phase current target value.

[0068] When supplying the A-phase current Ia that flows from terminal A2 to terminal A1 to the A-phase coil 61c: (1) The current control unit 77C turns off switches SW11 and SW14. (2) The current control unit 77C controls the ON time of switches SW12 and SW13 so that the magnitude of the A-phase current Ia is the same as the magnitude of the A-phase current target value.

[0069] When supplying the B-phase current Ib from terminal B1 to terminal B2 to the B-phase coil 62c: (1) The current control unit 77C turns off switches SW22 and SW23. (2) The current control unit 77C controls the ON time of switches SW21 and SW24 so that the magnitude of the B-phase current Ib is the same as the magnitude of the B-phase current target value.

[0070] When supplying the B-phase current Ib from terminal B2 to terminal B1 to the B-phase coil 62c: (1) The current control unit 77C turns off switches SW21 and SW24. (2) The current control unit 77C controls the ON time of switches SW22 and SW23 so that the magnitude of the B-phase current Ib is the same as the magnitude of the B-phase current target value.

[0071] The A-phase current Ia and B-phase current Ib are currents controlled by pulse width modulation (constant current drive) to reach target values. Each switch is turned on / off at time intervals shorter than the pulse P period so that the A-phase current Ia and B-phase current Ib reach their respective target values.

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

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

[0074] Computer 80 has input ports IP1 and IP2. Input ports IP1 and IP2 are connected to the downstream ends of H-bridge circuits 77A and 77B. The voltage input to input port IP1 is converted by the ADC into information indicating the A-phase current Ia flowing through the A-phase coil 61c. The voltage input to input port IP2 is converted by the ADC into information indicating the B-phase current Ib flowing through the B-phase coil 62c. Computer 80 (CPU) obtains the information converted by the ADC as the A-phase current Ia and the B-phase current Ib.

[0075] The computer 80 functions as a rotation control unit 81, an acquisition unit 82, and an estimation unit 83 by having the CPU execute a program stored in ROM.

[0076] The rotation control unit 81 inputs a pulse P to the stepping motor 66 to rotate the rotor 41 in the first or second direction. Specifically, the rotation control unit 81 controls the motor driver 77 based on commands from the air conditioner 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.

[0077] The acquisition unit 82 acquires information relating to the change period from the first current value to the second current value for the A-phase current Ia flowing through the A-phase coil 61c. The acquisition unit 82 may also acquire information relating to the change period from the first current value to the second current value for the B-phase current Ib flowing through the B-phase coil 62c. An example of information relating to the change period is shown below.

[0078] If the first current value is "-It" and the second current value is "+It", then the information is: (1) The change time (rise time) from the start to the end of the change period (rise period), (2) The average of multiple rise times, (3) Duty cycle in judgment period E including the rise period, (4) The degree of difference between the waveform of the A-phase current Ia during the judgment period E, including the rise time, and the reference waveform of the A-phase current Ia, or (5) The slope of the waveform of the A-phase current Ia during the rise time.

[0079] If the first current value is "+It" and the second current value is "-It", then the information is: (6) The change time (falling period) from the start to the end of the change period (falling period), (7) The average of multiple fall times, (8) Duty cycle in judgment period E including fall time, (9) The degree of difference between the waveform of phase A current Ia during the judgment period E, including the falling edge period, and the reference waveform of phase A current Ia, or (10) The slope of the A-phase current waveform during the falling edge period.

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

[0081] The estimation unit 83 estimates the temperature T of the rotor 41 using the information related to the change period acquired by the acquisition unit 82.

[0082] The inventors installed the electric valve device 1 in a constant temperature bath and, after the temperature T of the rotor 41 of the electric valve 5 and the coils of the stator 60 (A-phase coil 61c and B-phase coil 62c) became the same as the temperature of the constant temperature bath, supplied a drive current to the coils and observed the waveform of the drive current flowing through the coils. The valve chamber 14 and the inner space 21 of the can 20 of the electric valve 5 are filled with refrigerant. The temperature of the refrigerant is also the same as the temperature of the constant temperature bath. The stator 60 is in contact with the can 20, and the temperature of the coils reflects the temperature of the can 20 (refrigerant and rotor 41).

[0083] Figures 12 and 13 show examples of the waveform of the drive current flowing through the A-phase coil 61c when the rotor 41 is rotated in the second direction. The power supply voltage of the motor driver 77 is 9V. The drive current waveforms shown in Figures 12 and 13 include the waveform of the drive current during the rise time. Figure 12 shows the waveform of the drive current when the temperature T (temperature of the constant temperature bath) of the rotor 41 is -30°C. Figure 13 shows the waveform of the drive current when the temperature T of the rotor 41 is 125°C.

[0084] As shown in Figure 12, when the temperature T of the rotor 41 is low, the rise time is relatively short. As shown in Figure 13, when the temperature T of the rotor 41 is high, the rise time is relatively long. The relationship between the temperature T of the rotor 41 and the rise time shows the same trend even when the power supply voltage and the rotation direction of the rotor 41 are changed. Figure 14 shows the relationship between the rotation direction of the rotor 41, the temperature T of the rotor 41, the power supply voltage, and the rise time. There is a relationship between the temperature T of the rotor 41 and the rise time. Therefore, the temperature T of the rotor 41 can be estimated using the rise time. In addition, the temperature T of the rotor 41 can also be estimated using the fall time, similar to the rise period. Figure 15 shows the change time rt (rise time) from the start to the end of the rise period of the A-phase current Ia and the change time ft (fall time) from the start to the end of the fall period.

[0085] Furthermore, as shown in Figure 12, when the temperature T of the rotor 41 is low, the slope of the rising waveform is relatively large. As shown in Figure 13, when the temperature T of the rotor 41 is high, the slope of the rising waveform is relatively small. The rising waveform is the waveform of the drive current during the rising period. Therefore, the temperature T of the rotor 41 can be estimated using the slope of the rising waveform. The slope of the rising waveform is calculated, for example, using multiple drive currents (current values) acquired at different timings during the rising period. Note that the temperature T of the rotor 41 can also be estimated using the waveform of the drive current during the falling period (falling waveform).

[0086] Next, the inventors measured the duty cycle of the drive current flowing through the coil. Figures 16 and 17 show examples of the drive current waveform and duty cycle during the determination period E, which includes the rise period (change period). Figure 16 shows the drive current waveform when the temperature T of the rotor 41 is low. Figure 17 shows the drive current waveform when the temperature T of the rotor 41 is high. "Including the change period" means "including at least a part of the change period." The determination period E only needs to include a part of the change period to the extent that the temperature T of the rotor 41 can be estimated.

[0087] During the rise-up period, the duty cycle is 100%. In the period following the rise-up period, when the drive current is maintained at the target value (+It), the duty cycle becomes less than 100%. As shown in Figure 16, when the temperature T of the rotor 41 is low, the number of times the duty cycle is 100% in the judgment period E is relatively small. As shown in Figure 17, when the temperature T of the rotor 41 is high, the number of times the duty cycle is 100% in the judgment period E is relatively large. Therefore, the temperature T of the rotor 41 can be estimated by using the duty cycle in the judgment period E, which includes the rise-up period.

[0088] Figure 18 shows the waveform of the drive current during the judgment period E, which includes the rise time (change period). In Figure 18, the dashed line shows the waveform of the drive current when the temperature T of the rotor 41 is low, and the solid line shows the waveform of the drive current when the temperature T of the rotor 41 is high. The waveform of the drive current when the temperature T of the rotor 41 is low is different from the waveform of the drive current when the temperature T of the rotor 41 is high. Therefore, the temperature T of the rotor 41 can be estimated by using the waveform of the drive current during the judgment period E, which includes the rise time.

[0089] Alternatively, the fall time (fall period) may be used to estimate the temperature T of the rotor 41. The temperature T of the rotor 41 can be estimated by using the fall time. The temperature T of the rotor 41 can be estimated by using the duty cycle in the judgment period E, which includes the fall period. The temperature T of the rotor 41 can be estimated by using the waveform of the drive current in the judgment period E, which includes the fall period.

[0090] In the electric valve 5, refrigerant is introduced into the inner space 21 of the can 20. The rotor 41 is immersed in the refrigerant. The refrigerant contains refrigerant oil. When the refrigerant temperature is low, the viscosity of the refrigerant oil is high, making it difficult for the rotor 41 to rotate. When the refrigerant temperature is high, the viscosity of the refrigerant oil is low, making it easy for the rotor 41 to rotate.

[0091] The magnetic force generated by the multiple magnetic poles of the rotor 41 is affected by the temperature T of the rotor 41. The temperature T of the rotor 41 is the same as the temperature of the refrigerant. When the temperature T of the rotor 41 is low, the magnetic force is strong and the rotor 41 rotates easily. When the temperature T of the rotor 41 is high, the magnetic force is weak and the rotor 41 rotates difficult.

[0092] Therefore, the characteristics of the stepping motor 66 change according to the temperature T of the rotor 41. The characteristics include the relationship between the drive current and the output torque. By supplying a drive current corresponding to the temperature T of the rotor 41 to the coil of the stator 60, the stepping motor 66 can output a torque above a specified value without consuming excess power.

[0093] The rotation control unit 81 sets target values for the A-phase current Ia and the B-phase current Ib based on the temperature T of the rotor 41 estimated by the estimation unit 83. FIG. 19 shows the relationship between the temperature T of the rotor 41 and the target values.

[0094] When the temperature T of the rotor 41 is lower than the first temperature determination value T1 (low temperature state), the rotation control unit 81 sets the low temperature target value ItL as the magnitude of the target value. When the temperature T of the rotor 41 is equal to or higher than the first temperature determination value T1 and equal to or lower than the second temperature determination value T2 (normal temperature state), the rotation control unit 81 sets the normal temperature target value ItR as the magnitude of the target value. When the temperature T of the rotor 41 is higher than the second temperature determination value T2 (high temperature state), the rotation control unit 81 sets the high temperature target value ItH as the magnitude of the target value.

[0095] The first temperature determination value T1 is greater than the lower limit value TL of the operating temperature range of the motorized valve 5, the second temperature determination value T2 is smaller than the upper limit value TH of the operating temperature range of the motorized valve 5, and the second temperature determination value T2 is greater than the first temperature determination value T1 (TL < T1 < T2 < TH). The low temperature target value ItL is greater than the normal temperature target value ItR, the high temperature target value ItH is greater than the normal temperature target value ItR, and the low temperature target value ItL is greater than the high temperature target value ItH (ItL > ItH > ItR). The first temperature determination value T1, the second temperature determination value T2, the low temperature target value ItL, the normal temperature target value ItR, and the high temperature target value ItH are appropriately set according to the configuration of the motorized valve device 1 and the like.

[0096] When the power is turned on, the motorized valve control device 70 (computer 80) reads the position of the rotor 41 stored in the non-volatile memory 75 as the current position Rp of the rotor 41. When the motorized valve control device 70 receives a valve body movement command including the target valve opening degree from the air conditioner control device 110, it performs a valve body movement operation. The valve body movement operation is an operation of rotating the rotor 41 from the current position Rp to a position corresponding to the target valve opening degree and setting the position as the new current position Rp. The motorized valve control device 70 stores the current position Rp in the non-volatile memory 75 immediately before the power is cut off.

[0097] The electric valve control device 70 performs a drive current setting operation in parallel with the valve body movement operation. Figures 20 to 22 show examples of the drive current setting operation (first operation example to third operation example).

[0098] A first example of operation of the electric valve control device 70 will be explained with reference to Figure 20.

[0099] The electric valve control device 70 determines whether the current position Rp of the rotor 41 is within the temperature estimation range (S110).

[0100] The rotation angle of the rotor 41 corresponding to pulse P with distance determination number F is defined as the travel distance M. The travel distance M is the rotation angle of the rotor 41 when pulse P with distance determination number F is input to the stepping motor 66. The distance determination number F is, for example, 50. (1) The electric valve control device 70 determines that the current position Rp of the rotor 41 is not within the temperature estimation range when the distance (rotation angle) between the current position Rp of the rotor 41 and the reference position Rx is less than or equal to the travel distance M. (2) The electric valve control device 70 determines that the current position Rp of the rotor 41 is not within the temperature estimation range when the distance between the current position Rp of the rotor 41 and the fully open position Rz is less than or equal to the travel distance M. (3) The electric valve control device 70 determines that the current position Rp of the rotor 41 is within the temperature estimation range when the conditions are not met in (1) or (2). The temperature estimation range includes the positions of the rotor 41 from the reference position Rx to the fully open position Rz, excluding (i) positions within a travel distance M from the reference position Rx, and (ii) positions within a travel distance M from the fully open position Rz.

[0101] The electric valve control device 70 terminates this operation when it determines that the current position Rp of the rotor 41 is not within the temperature estimation range (N in S110).

[0102] When the electric valve control device 70 determines that the current position Rp of the rotor 41 is within the temperature estimation range (Y in S110), it calculates the average value Ka of multiple rise times of the drive current supplied to the coil of the stator 60 (S120). Specifically, the electric valve control device 70 obtains the rise time of the A-phase current Ia, and after obtaining the rise times of a target number G, it calculates their average value Ka. The target number G is, for example, 10, and is a number less than or equal to the distance determination number F.

[0103] The electric valve control device 70 estimates the temperature T of the rotor 41 using the average value Ka (S130). For example, the non-volatile memory 75 stores a data table (temperature table) containing multiple pairs of the average value Ka and the temperature T of the rotor 41 corresponding to that average value Ka, and the electric valve control device 70 reads the temperature T of the rotor 41 corresponding to the calculated average value Ka from the temperature table. In other words, the electric valve control device 70 obtains the temperature T of the rotor 41 from the temperature table stored in the non-volatile memory 75 using the average value Ka. The temperature table is set up based on, for example, measured values ​​or simulation results.

[0104] When the temperature T of the rotor 41 is lower than the first temperature determination value T1 (Y: low temperature state in S140), the electric valve control device 70 sets the low temperature target value ItL as the magnitude of the target value of the drive current (S150) and terminates this operation.

[0105] When the temperature T of the rotor 41 is greater than or equal to the first temperature determination value T1 and greater than the second temperature determination value T2 (N in S140, Y in S160: high temperature state), the electric valve control device 70 sets the high temperature target value ItH as the magnitude of the target value of the drive current (S170) and terminates this operation.

[0106] The electric valve control device 70 terminates this operation when the temperature T of the rotor 41 is greater than or equal to the first temperature determination value T1 and less than or equal to the second temperature determination value T2 (N in S140, N in S160: normal temperature state), setting the target value ItR for the drive current as the target value for normal temperature (S180).

[0107] The electric valve control device 70 may also estimate the temperature T of the rotor 41 using the slope of the waveform of the A-phase current Ia. Specifically, the electric valve control device 70 calculates the slope using multiple A-phase currents Ia (current values) acquired at different timings during the rise time, and calculates the average value of the multiple slopes. Then, the electric valve control device 70 uses this average value to obtain the temperature T of the rotor 41 from a temperature table (which includes multiple pairs of the average value and the corresponding temperature T of the rotor 41) stored in the non-volatile memory 75.

[0108] Next, a second example of operation of the electric valve control device 70 will be explained with reference to Figure 21.

[0109] The electric valve control device 70 determines whether the current position Rp of the rotor 41 is within the temperature estimation range (S210).

[0110] The electric valve control device 70 terminates this operation when it determines that the current position Rp of the rotor 41 is not within the temperature estimation range (N in S210).

[0111] When the electric valve control device 70 determines that the current position Rp of the rotor 41 is within the temperature estimation range (Y in S210), it calculates the average value Daa of multiple duty cycles in the drive current supplied to the coil of the stator 60 (S220). Specifically, the electric valve control device 70 acquires multiple duty cycles of the A-phase current Ia during the determination period E, which includes the rise period, and calculates the average value Daa of the multiple duty cycles. When the electric valve control device 70 calculates the average value Daa of the target number G to be acquired, it calculates the average value Daa of those.

[0112] The electric valve control device 70 estimates the temperature T of the rotor 41 using the average value Daa (S230). For example, the non-volatile memory 75 stores a temperature table containing multiple pairs of the average value Daa and the rotor temperature T corresponding to that average value Daa, and the electric valve control device 70 reads the rotor temperature T corresponding to the calculated average value Daa from the temperature table. In other words, the electric valve control device 70 obtains the temperature T of the rotor 41 from the temperature table stored in the non-volatile memory 75 using the average value Daa.

[0113] The operations in steps S210 and S240-S280 are the same as those in steps S110 and S140-S180 in Figure 20. The explanation of the operations in steps S210 and S240-S280 is omitted.

[0114] The electric valve control device 70 may also estimate the temperature T of the rotor 41 using the number of times the A-phase current Ia reaches 100% of its duty cycle. Specifically, the electric valve control device 70 counts the number of times the A-phase current Ia reaches 100% of its duty cycle during the determination period E and calculates the average value of multiple such counts. Then, the electric valve control device 70 uses this average value to obtain the temperature T of the rotor 41 from a temperature table (which includes multiple pairs of the average value and the corresponding rotor temperature T) stored in the non-volatile memory 75.

[0115] Next, a third example of operation of the electric valve control device 70 will be explained with reference to Figure 22.

[0116] First, let's explain the difference index value sv used in the third example of operation.

[0117] The difference index value sv is a value that indicates the degree of difference between the waveform of the A-phase current Ia and the reference waveform of the A-phase current Ia. The larger the difference index value sv, the greater the degree of difference between the waveform of the A-phase current Ia and the reference waveform of the A-phase current Ia. The electric valve control device 70 calculates the difference index value sv.

[0118] The electric valve control device 70 acquires the waveform of the A-phase current Ia during the determination period E, which includes the rise time. Specifically, the electric valve control device 70 acquires the A-phase current Ia (current value ia) in a time series at a predetermined sampling period (100 μs).

[0119] The time-series acquired current value ia is the waveform of the A-phase current Ia. In this specification, "waveform" refers to the temporal change of a physical quantity (current) at a fixed point. When visualizing a "waveform," it is represented on a coordinate plane with the physical quantity on the vertical axis and time on the horizontal axis. Invisible elements such as data tables in which physical quantity data and time data are associated and stored in the RAM or non-volatile memory 75 of the computer 80 are also included in the "waveform."

[0120] The reference waveform for the A-phase current Ia is set based, for example, on the waveform of the A-phase current Ia when the temperature T of the rotor 41 is -30°C. Separate reference waveforms for the A-phase current Ia are prepared for use when the rotor 41 is rotating in the first direction and for use when the rotor 41 is rotating in the second direction. The reference waveforms for the A-phase current Ia are stored in the non-volatile memory 75 during the manufacture of the electric valve device 1.

[0121] The reference waveform of the A-phase current Ia is stored in the non-volatile memory 75 as a data table (waveform table). In the waveform table, a time tc at predetermined time intervals from the start of the judgment period E (time 0) is associated with the reference current value ir at that time tc. The interval of time tc is the same as the sampling period (100 μs). One waveform table has 40 pairs of time tc and reference current value ir. Figure 24 shows an example of a waveform table. In Figure 24, the unit of time tc is [μs] and the unit of reference current value ir is [mA].

[0122] When the electric valve control device 70 acquires a current value ia at acquisition time t, it reads a reference current value ir from the waveform table that is associated with time tc corresponding to the acquisition time t. The electric valve control device 70 calculates a value (difference value dv) by subtracting the reference current value ir from the current value ia. The electric valve control device 70 calculates an intermediate value (dv2) by squaring the difference value dv. The electric valve control device 70 calculates a difference index value sv by summing up multiple intermediate values ​​dv2 calculated for one judgment period E.

[0123] When the current value ia acquired at acquisition time t between the start (time t1) and end (time t2) of the judgment period E is denoted as ia[t], and the reference current value ir associated with time tc corresponding to acquisition time t in the waveform table is denoted as ir[t], the difference index value sv is given by the following equation (1).

[0124]

number

[0125] The difference index value sv is not limited to that calculated using the above formula (1). The difference index value sv may, for example, relate to the change in the magnitude of the current value ia at acquisition time t. Specifically, the electric valve control device 70 calculates the difference value dv between the current value ia acquired at acquisition time t and the reference current value ir associated with time tc corresponding to acquisition 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 during the judgment period E that are greater than or equal to a predetermined difference judgment value as the difference index value. Such a difference index value also appropriately reflects the degree of difference in the shape of the waveform.

[0126] In the third example of operation, the electric valve control device 70 determines whether the current position Rp of the rotor 41 is within the temperature estimation range (S310).

[0127] The electric valve control device 70 terminates this operation when it determines that the current position Rp of the rotor 41 is not within the temperature estimation range (N in S310).

[0128] When the electric valve control device 70 determines that the current position Rp of the rotor 41 is within the temperature estimation range (Y in S310), it calculates the average value sva of several difference index values ​​sv related to the drive current supplied to the coil of the stator 60 (S320). Specifically, the electric valve control device 70 acquires the waveform of the A-phase current Ia during the determination period E, which includes the rise time, and calculates the difference index value sv. After calculating the difference index values ​​sv for the target number G of acquisition targets, the electric valve control device 70 calculates their average value sva. The larger the average value sva, the greater the degree of difference between the waveform of the A-phase current Ia and the reference waveform of the A-phase current Ia. The reference waveform of the A-phase current Ia is based on the waveform of the A-phase current Ia when the temperature T of the rotor 41 is -30℃. Therefore, if the average value sva is small, it is estimated that the temperature T of the rotor 41 is low, and if the average value sva is large, it is estimated that the temperature T of the rotor 41 is high.

[0129] The electric valve control device 70 estimates the temperature T of the rotor 41 using the average value sva (S330). Specifically, the non-volatile memory 75 stores a temperature table containing multiple pairs of the average value sva and the rotor temperature T corresponding to that average value sva, and the electric valve control device 70 reads the rotor temperature T corresponding to the calculated average value sva from the temperature table. In other words, the electric valve control device 70 obtains the temperature T of the rotor 41 from the temperature table stored in the non-volatile memory 75 using the average value sva.

[0130] The operations in steps S310 and S340-S380 are the same as those in steps S110 and S140-S180 in Figure 20. The explanation of the operations in steps S310 and S340-S380 is omitted.

[0131] The reference waveform for the A-phase current Ia may be based on the waveform of the A-phase current Ia when the rotor temperature T of 41 is 125°C. In this case, a small average value sva suggests that the rotor temperature T of 41 is high, and a large average value sva suggests that the rotor temperature T of 41 is low.

[0132] In the first to third operation examples, the electric valve control device 70 estimates the temperature T of the rotor 41 using the A-phase current Ia during the rise period, but it may also estimate the temperature T of the rotor 41 using the A-phase current Ia during the fall period. In the first to third operation examples, the electric valve control device 70 estimates the temperature T of the rotor 41 using the A-phase current Ia, but it may also estimate the temperature T of the rotor 41 using the B-phase current Ib, or it may also estimate the temperature T of the rotor 41 using both the A-phase current Ia and the B-phase current Ib.

[0133] 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 chamber 14 and a valve port 17, a cylindrical can 20 attached to the valve body 10, a rotor 41 positioned in the inner space 21 of the can 20, a stator 60, and a valve body 30 that moves relative to the valve port 17 when the rotor 41 rotates. The valve chamber 14 and the inner space 21 are connected. The stator 60 includes a hollow annular yoke in contact with the outer surface of the can 20 and coils (A-phase coil 61c, B-phase coil 62c) housed in the yoke. The coils are supplied with drive currents (A-phase current Ia, B-phase current Ib) to rotate the rotor 41. The electric valve control device 70 includes a computer 80 that estimates the temperature T of the rotor 41 based on the drive currents flowing through the coils.

[0134] In the electric valve 5, the valve chamber 14 and the inner space 21 of the can 20 are connected, and the refrigerant from the valve chamber 14 is introduced into the inner space 21. The temperature of the refrigerant is reflected in the temperature T of the rotor 41 and also in the temperature of the coil via the can 20 and the yoke. The temperature of the coil and the temperature T of the rotor 41 are related, and the current flowing through the coil is related to the temperature T of the rotor 41. In this way, the temperature T of the rotor 41 can be estimated with high accuracy using an electric valve control device 70 with a simple configuration.

[0135] Furthermore, the computer 80 estimates the temperature T of the rotor 41 using information relating to the rise period until the drive current flowing through the coil changes from a first current value to a second current value. The information relating to the rise period is the change time (rise time) from the start to the end of the rise period (first operation example). The information relating to the rise period is the duty cycle of the pulse width modulation method in the judgment period E including the rise period (second operation example), or the information relating to the rise period is the degree of difference between the waveform of the drive current flowing through the coil and the reference waveform of the drive current in the judgment period E including the rise period (third operation example). The information relating to the rise period may also be the slope of the waveform of the drive current flowing through the coil during the rise period. In this way, the electric valve control device 70 can estimate the temperature T of the rotor 41 based on information that can be obtained relatively easily.

[0136] Furthermore, the coils of the stator 60 are connected to the motor driver 77. The computer 80 controls the motor driver 77 so that a drive current of a magnitude corresponding to the temperature T of the rotor 41 is supplied to the coils. In this way, the stepping motor 66 can output torque above a specified value without consuming excess power.

[0137] When the electric valve control device 70 receives a valve body movement command, it performs a drive current setting operation in parallel with the valve body movement operation. The electric valve control device 70 may perform the drive current setting operation in parallel with the valve body movement operation only if a predetermined time (e.g., 1 hour) has elapsed since the previous valve body movement command was received when the electric valve control device 70 receives the valve body movement command. The predetermined time is set to be sufficient time for the temperature of the coil, which has risen due to the drive current, to decrease and for the temperature difference between the rotor 41 and the coil to disappear (including the temperature difference to disappear substantially). In this way, the electric valve control device 70 can estimate the temperature T of the rotor 41 more accurately.

[0138] The electric valve control device 70 may autonomously perform the drive current setting operation. For example, the electric valve control device 70 performs the drive current setting operation when the power is turned on, or when a predetermined time (e.g., 1 hour) has elapsed since the last drive current setting operation. In this drive current setting operation, the electric valve control device 70 inputs a pulse P corresponding to the current position Rp of the rotor 41 to the stepping motor 66. That is, the electric valve control device 70 supplies a drive current to the coil corresponding to the pulse P. For example, when pulse P[1] corresponds to the current position Rp of the rotor 41, the electric valve control device 70 controls the motor driver 77 so that "+It" is supplied as the A-phase current Ia and "-It" is supplied as the B-phase current Ib. When pulse P[2] corresponds to the current position Rp of the rotor 41, the electric valve control device 70 controls the motor driver 77 so that "+It" is supplied as the A-phase current Ia and "+It" is supplied as the B-phase current Ib. This allows the electric valve control device 70 to estimate the temperature T of the rotor 41 based on the current flowing through the coil while keeping the rotor 41 at its current position Rp. The pulse P corresponding to the current position Rp of the rotor 41 is also the last pulse P input to the stepping motor 66.

[0139] The electric valve control device 70 may perform the following operations. After the power is turned on, the electric valve control device 70 estimates the temperature T of the rotor 41. Then, when the temperature T of the rotor 41 is lower than the operating temperature threshold value (e.g., 25°C), the electric valve control device 70 supplies a current to the coil via the motor driver 77 to raise the temperature T of the rotor 41. As a result, the coil generates heat, and the refrigerant in the can 20 and its inner space 21, as well as the rotor 41, are heated. The electric valve control device 70 inputs a pulse P corresponding to the current position Rp of the rotor 41 to the stepping motor 66. That is, the electric valve control device 70 supplies a drive current to the coil corresponding to the pulse P. As a result, the electric valve control device 70 estimates the temperature T of the rotor 41 based on the current flowing through the coil, and supplies a current to the coil to raise the temperature T of the rotor 41, while keeping the rotor 41 at its current position Rp. The electric valve control device 70 repeatedly estimates the temperature T of the rotor 41 and supplies current to the coil until the temperature T of the rotor 41 reaches the operating temperature determination value. Before estimating the temperature T of the rotor 41, the electric valve control device 70 waits to supply current to the coil until the temperature of the coil, which has risen due to the current, drops to a temperature suitable for estimation. In this way, the electric valve control device 70 can raise the temperature T of the rotor 41 to a temperature suitable for the operation of the stepping motor 66. The operating temperature determination value is set appropriately according to the configuration of the electric valve device 1.

[0140] The electric valve control device 70 may have a timer that operates even when the refrigeration cycle system including the electric valve control device 70 is stopped. The timer is, for example, built into the computer 80. In this configuration, the electric valve control device 70 estimates the temperature T of the rotor 41 after a predetermined waiting time has elapsed since the refrigeration cycle system stopped. Specifically, when the refrigeration cycle system starts operating and power is supplied to the electric valve control device 70, the electric valve control device 70 obtains from the timer the time that has elapsed since the refrigeration cycle system stopped. If the time obtained from the timer is greater than or equal to the waiting time, the electric valve control device 70 performs a drive current setting operation. In the drive current setting operation, the electric valve control device 70 estimates the temperature of the rotor 41. The waiting time is set to be sufficient time for the temperature difference between the rotor 41 and the coil to disappear (including substantially eliminating the temperature difference). The waiting time is set to, for example, 3 to 12 hours. The waiting time may be set to the time when the temperature of the refrigerant, the temperature of the rotor 41, and the temperature of the coil are the same as (including substantially the same as) the ambient temperature of the refrigeration cycle system. In this way, the electric valve control device 70 can estimate the temperature T of the rotor 41 more accurately.

[0141] The electric valve control device 70 may have a temperature sensor. The temperature sensor is mounted on the circuit board 71 and connected to the computer 80. The temperature sensor may also be built into the computer 80. The stator 60 and the circuit board 71 are housed in, for example, a housing (not shown), and the temperature sensor outputs a signal corresponding to the temperature of the inner space of the housing (i.e., the space in which the stator 60 is located). The inner space is a closed space. An example of the operation of the electric valve control device 70 having this configuration (fourth operation example) will be described with reference to Figure 23. The electric valve control device 70 performs this operation immediately after the power is turned on.

[0142] The electric valve control device 70 inputs a pulse P corresponding to the current position Rp of the electric valve 5 to the stepping motor 66 (S410). The pulse P corresponding to the current position Rp is the last pulse P input to the stepping motor 66. The rotor 41 does not rotate even when the pulse P corresponding to the current position Rp is input to the stepping motor 66. In step S410, multiple pulses P are input to the stepping motor 66 at intervals. For example, when the last pulse P input is pulse P[1], 10 pulses P[1] are input to the stepping motor 66 at intervals (e.g., 10 ms). In response to the input of pulses P to the stepping motor 66, a drive current is supplied to the coil of the stator 60.

[0143] The electric valve control device 70 calculates the average value Ka of multiple rise times of the drive current supplied to the coil of the stator 60 (S420). For example, the electric valve control device 70 obtains 10 rise times and calculates their average value Ka. The electric valve control device 70 may also calculate the average value Ka of multiple fall times of the drive current. The electric valve control device 70 estimates the temperature T of the rotor 41 using the average value Ka (S430).

[0144] The electric valve control device 70 obtains the temperature S of the inner space of the housing from the signal output by the temperature sensor (S440).

[0145] When the temperature T of the rotor 41 is higher than the rotor temperature determination value Tr (N in S450), the electric valve control device 70 sets the ambient temperature target value ItR as the magnitude of the target value of the drive current (S470) and terminates this operation.

[0146] When the temperature S of the inner space of the housing is higher than the ambient temperature determination value Ts (Y in S450, N in S460), the electric valve control device 70 sets the ambient temperature target value ItR as the magnitude of the target value of the drive current (S470) and terminates this operation.

[0147] The electric valve control device 70 terminates this operation when the temperature T of the rotor 41 is less than or equal to the rotor temperature determination value Tr and the temperature S of the inner space is less than or equal to the space temperature determination value Ts (Y in S450, Y in S460), setting the low-temperature target value ItL as the target value of the drive current (S480). The low-temperature target value ItL is greater than the normal temperature target value ItR. The normal temperature target value ItR is the normal value of the drive current.

[0148] In this way, the electric valve control device 70 can supply an appropriate drive current to the coil of the stator 60 based on the temperature T of the rotor 41 and the temperature S of the inner space of the housing. After a predetermined time (for example, 1 hour) has elapsed since this operation, the electric valve control device 70 may set the ambient temperature target value ItR as the magnitude of the target value of the drive current. The electric valve control device 70 may perform this operation at predetermined intervals (for example, every hour) after the power is turned on.

[0149] In this specification, terms indicating shapes such as "cylinder" and "column" are also used to refer to members or parts of members that substantially have the shape of those terms. For example, "cylindrical member" includes both cylindrical members and substantially cylindrical members. Furthermore, in this specification, the term "same" may include both strictly identical and substantially identical items.

[0150] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, deletions, design modifications, and combinations of features of the embodiments, as appropriate by those skilled in the art, are also included within the scope of the present invention, as long as they do not contradict the spirit of the invention. [Explanation of Symbols]

[0151] 1…Electric valve device, 5…Electric valve, 10…Valve body, 14…Valve chamber, 17…Valve port, 18…Valve seat, 20…Can, 30…Valve body, 40…Drive mechanism, 41…Rotor, 42…Valve shaft holder, 42c…Female thread, 42s…Movable stopper, 43…Guide bush, 43c…Male thread, 44…Stopper member, 44s…Fixed stopper, 49…Stopper mechanism, 60…Stator, 61…A-phase stack, 61c…A-phase coil, 62…B-phase stack, 62c…B-phase coil, 66…Stepping motor, 70…Electric valve control device, 75…Non-volatile memory, 76…Communication device, 77…Motor driver, 80…Computer

Claims

1. An electric valve control device for controlling an electric valve having a valve body having a valve chamber and a valve port, a cylindrical case attached to the valve body and having an inner space connected to the valve chamber, a rotor disposed in the inner space, a stator having a hollow annular yoke in contact with the outer circumferential surface of the case and a coil housed in the yoke, and a valve body facing the valve port in the valve chamber and moving relative to the valve port when the rotor rotates, wherein a drive current for rotating the rotor is supplied to the coil, The electric valve control device includes a processing device that estimates the temperature of the rotor based on the current flowing through the coil, The aforementioned drive current is a current that alternately changes between a first current value and a second current value. An electric valve control device that estimates the temperature of the rotor using information relating to the change period from the first current value to the second current value in which the current flowing through the coil changes.

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

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

4. The electric valve control device according to claim 1, wherein the information relating to the change period is the degree of difference between the waveform of the current flowing through the coil and the reference waveform of the current during a determination period including the change period.

5. The electric valve control device according to claim 1, wherein the information relating to the change period is the slope of the waveform of the current flowing through the coil during the change period.

6. The coil is connected to a current supply device. The electric valve control device according to claim 1, wherein the processing device controls the current supply device so that a drive current of a magnitude corresponding to the temperature of the rotor is supplied to the coil.

7. The coil is connected to a current supply device. The electric valve control device according to claim 1, wherein the processing device controls the current supply device so that when the temperature of the rotor is lower than the operating temperature determination value, a current is supplied to the coil to raise the temperature of the rotor.

8. An electric valve control device for controlling an electric valve having a valve body having a valve chamber and a valve port, a cylindrical case attached to the valve body and having an inner space connected to the valve chamber, a rotor disposed in the inner space, a stator having a hollow annular yoke in contact with the outer surface of the case and a coil housed in the yoke, and a valve body facing the valve port in the valve chamber and moving relative to the valve port when the rotor rotates, wherein a drive current for rotating the rotor is supplied to the coil, The electric valve control device includes a processing device that estimates the temperature of the rotor based on the current flowing through the coil, The aforementioned electric valve is incorporated into a refrigeration cycle system and used to control the flow rate of the refrigerant. The processing device estimates the temperature of the rotor after a waiting period has elapsed since the refrigeration cycle system stopped. An electric valve control device wherein the aforementioned waiting time is set to a length of time at which the temperature difference between the rotor and the coil disappears.

9. An electric valve control device for controlling an electric valve having a valve body having a valve chamber and a valve port, a cylindrical case attached to the valve body and having an inner space connected to the valve chamber, a rotor disposed in the inner space, a stator having a hollow annular yoke in contact with the outer circumferential surface of the case and a coil housed in the yoke, and a valve body facing the valve port in the valve chamber and moving relative to the valve port when the rotor rotates, wherein a drive current for rotating the rotor is supplied to the coil, The electric valve control device includes a processing device that estimates the temperature of the rotor based on the current flowing through the coil, The coil is connected to a current supply device. The electric valve control device has a temperature sensor that outputs a signal corresponding to the temperature of the space in which the stator is located, The aforementioned processing apparatus The temperature of the rotor is estimated based on the current flowing through the coil, and the temperature of the space is obtained from the signal. When the rotor temperature is higher than the rotor temperature determination value or the ambient temperature is higher than the ambient temperature determination value, the current supply device is controlled so that a normal-sized drive current is supplied to the coil. An electric valve control device that controls the current supply device so that a drive current larger than the normal size is supplied to the coil when the temperature of the rotor is below a rotor temperature determination value and the temperature of the space is below a space temperature determination value.

10. The electric valve control device according to claim 9, wherein the electric valve has a housing that accommodates the stator and the temperature sensor.

11. An electric valve device having the electric valve and the electric valve control device described in claim 1.

12. A control method for an electric valve comprising: a valve body having a valve chamber and a valve port; a cylindrical case attached to the valve body and having an inner space connected to the valve chamber; a rotor disposed in the inner space; a stator having a hollow annular yoke in contact with the outer surface of the case and a coil housed in the yoke; and a valve body facing the valve port in the valve chamber and moving relative to the valve port when the rotor rotates, wherein a drive current for rotating the rotor is supplied to the coil, The aforementioned drive current is a current that alternately changes between a first current value and a second current value. Using information relating to the change period from the first current value to the second current value in which the current flowing through the coil changes, the temperature of the rotor is estimated. A method for controlling an electric valve, characterized by supplying the drive current to the coil in an amount corresponding to the temperature of the rotor.

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