Motorized valve control device, motorized valve device, and motorized valve control method

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

Motor-operated valve control device, motor-operated valve device, and motor-operated valve control method

[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.

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

[0003] Japanese Patent Application Laid-Open No. 2023-73091

[0004] A refrigerant is introduced into the inner space of the can. The rotor 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 to rotate. When the refrigerant temperature is high, the viscosity of the refrigerant oil is low, making it easy for the rotor to rotate.

[0005] The magnetic force generated by the rotor's multiple magnetic poles is affected by the rotor's temperature, which is the same as the temperature of the coolant.

[0006] Motor-operated valves are required to operate normally when the ambient temperature is within a specified operating temperature range. Therefore, the magnitude of the drive current is set to suit strict temperature conditions so that the stepping motor can output torque greater than the specified value when the ambient temperature is within the operating temperature range. However, when the temperature conditions are not strict, the drive current may be larger than necessary, which could result in the stepping motor consuming excessive power.

[0007] The motor-operated valve control device has a circuit board and a temperature sensor mounted on the circuit board. The motor-operated valve control device estimates the rotor temperature based on the temperature sensor signal and controls the magnitude of the drive current according to the rotor temperature, thereby preventing the stepping motor from consuming excessive power. However, the temperature sensor mounted on the circuit board is far from the can, making it difficult for the motor-operated valve control device to estimate the rotor temperature with high accuracy. Placing the temperature sensor on the can to estimate the rotor temperature with high accuracy would complicate the configuration of the motor-operated valve control device.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a motor-operated valve control device and motor-operated valve device, as well as a motor-operated valve control method, which have a simple configuration and are capable of estimating rotor temperature with high accuracy.

[0009] The inventors conducted extensive research using multiple motor-operated valves to supply current to the stator coils and measure the current flowing through the coils. As a result, they discovered that the current flowing through the coils is related to the rotor temperature, leading to the present invention.

[0010] In order to achieve the above object, one aspect of the present invention provides an electric valve control device 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 peripheral surface of the case and a coil housed in the yoke; and a valve disc facing the valve port in the valve chamber and moving relative to the valve port as the rotor rotates, the electric valve control device controlling an electric valve in which a drive current for rotating the rotor is supplied to the coil, and characterized by 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 alternates between a first current value and a second current value, and the processing device estimates the temperature of the rotor using information related to the change period from the first current value to the second current value of the current flowing through the coil.

[0012] In the present invention, it is preferable that the information relating to the change period is a 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 pulse width modulation, and the information relating to the change period is a duty cycle of the pulse width modulation in a determination period that includes the change period.

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

[0015] In the present invention, it is preferable that the information relating to the change period is a gradient 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 the drive current having a 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 that the processing device controls the current supply device so that, when the temperature of the rotor is lower than the operating temperature judgment value, a current for raising the temperature of the rotor is supplied to the coil.

[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 time has elapsed since the refrigeration cycle system was stopped, and that the waiting time is set to a length that eliminates the temperature difference between the rotor and the coil.

[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 according to the temperature of the space in which the stator is placed, 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, and controls the current supply device so that a normal magnitude of the drive current is supplied to the coil when the temperature of the rotor is higher than a rotor temperature determination value or the temperature of the space is higher than a space temperature determination value, and controls the current supply device so that a drive current larger than the normal magnitude is supplied to the coil when the temperature of the rotor is equal to or lower than the rotor temperature determination value and the temperature of the space is equal to or lower than the space temperature determination value.

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

[0021] In order to achieve the above object, a motor-operated valve device according to another aspect of the present invention includes the motor-operated valve and the motor-operated valve control device.

[0022] In order to achieve the above object, another aspect of the present invention provides a control method for an electrically operated 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 hollow annular yoke in contact with the outer peripheral surface of the case; a stator having 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 as the rotor rotates, wherein a drive current for rotating the rotor is supplied to the coil, and the control method comprises estimating the temperature of the rotor based on the current flowing through the coil, and supplying the drive current to the coil at a magnitude corresponding to the temperature of the rotor.

[0023] According to the present invention, the valve chamber and the internal space of the case are connected, and the fluid in the valve chamber is introduced into the internal space of the case. The temperature of the fluid is reflected in the temperature of the rotor and, via the case and yoke, in the temperature of the coil. There is a relationship between the temperature of the coil and the temperature of the rotor, and the current flowing through the coil is also 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. As a result, the rotor temperature can be estimated with high accuracy using a motor-operated valve control device with a simple configuration.

[0024] 1 is a block diagram of an air conditioner having an electric valve device;

[0023] FIG. 1 is a cross-sectional view of the electric valve device;

[0024] FIG. 2 is a plan view of the valve stem holder, movable stopper, fixed stopper, rotor, and stator of the electric valve device;

[0025] FIG. 3 is a schematic diagram showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[1] is input);

[0026] FIG. 4 is a schematic diagram showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[2] is input);

[0027] FIG. 5 is a schematic diagram showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[3] is input);

[0028] FIG. 6 is a schematic diagram showing the positional relationship between the magnetic poles of the rotor and the pole teeth of the stator (when pulse P[4] is input);

[0029] FIG. 7 is a schematic diagram showing a computer, a motor driver, and a stepping motor included in an electric valve control device of the electric valve device;

[0029] FIG. 8 is a diagram showing an example of the relationship between pulses input to the stepping motor and step signals and direction signals input to the motor driver;

[0029] FIG. 9 is a diagram showing an example of the correspondence relationship between pulses and A-phase current target values ​​and B-phase current target values;

[0029] FIG. 10 is a diagram showing an example of the waveforms of A-phase current and B-phase current. 1 is a diagram showing an example of the waveform of a drive current flowing through a stator coil. FIG. 2 is a diagram showing another example of the waveform of a drive current flowing through a stator coil. FIG. 3 is a diagram showing an example of the relationship between the rotation direction of the rotor, the temperature of the rotor, the power supply voltage, and the rise time. FIG. 4 is a diagram showing a schematic diagram of the waveform of a drive current flowing through a stator coil. FIG. 5 is a diagram showing a schematic diagram of an example of the relationship between the drive current waveform and the duty cycle (when the rotor temperature is low). FIG. 6 is a diagram showing another example of the relationship between the drive current waveform and the duty cycle. FIG. 7 is a diagram showing a schematic diagram of two drive current waveforms (when the rotor temperature is high). FIG. 8 is a diagram showing an example of the relationship between the rotor temperature and the target value of the drive current. A flowchart showing a first operation example of the motor-operated valve control device. A flowchart showing a second operation example of the motor-operated valve control device. A flowchart showing a third operation example of the motor-operated valve control device. A flowchart showing a fourth operation example of the motor-operated valve control device. FIG. 9 is a diagram showing an example of a data table of the reference waveform of the drive current.

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

[0026] The motor-operated 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 for controlling the flow rate of a refrigerant. The motor-operated valve device 1 has a motor-operated valve 5 and a motor-operated valve control device 70. Fig. 1 shows a block diagram of an air conditioner 100 having the motor-operated valve device 1. Fig. 2 shows a cross-sectional view of the motor-operated 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, which are connected in this 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 connected to the electric valve device 1 (electric valve control device 70) so that it can communicate with them. The air conditioner control device 110 uses the electric valve device 1 to control the flow rate of refrigerant flowing through the piping 105.

[0028] The motor-operated valve 5 includes a valve body 10 , a can 20 , a valve element 30 , a drive mechanism 40 , and a stator 60 .

[0029] The valve body 10 includes 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 port 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 port 17. The main body member 11 has an annular valve seat 18 that surrounds the valve port 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 that communicates with 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 peripheral edge of the connecting member 13 is joined to the upper end of the main body member 11. The main body member 11 and the connecting member 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 lower end of the can 20 is open and the upper end is closed. The lower end of the can 20 is joined to the outer periphery of the connecting member 13. An inner space 21 of the can 20 is connected to the valve chamber 14. A 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 step portion 34, which is an upward-facing annular flat surface. The step portion 34 is located at the connection between the first shaft portion 31 and the second shaft portion 32. The valve portion 33 has a 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 located in the valve port 17. A variable throttle portion is formed between the valve portion 33 and the valve port 17. The valve portion 33 faces the valve port 17 and the valve seat 18. When the valve portion 33 comes into contact with the valve seat 18, the valve port 17 closes. When the valve portion 33 moves away from the valve seat 18, the valve port 17 opens.

[0032] The drive mechanism 40 moves the valve element 30 in the vertical direction (the direction of the axis L). The movement of the valve element 30 opens and closes the valve port 17. The drive mechanism 40 has 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] Fig. 3 shows a plan view of the rotor 41, the valve stem holder 42, the movable stopper 42s, the fixed stopper 44s, and the stator 60. Fig. 3 also shows a schematic representation of the magnetic poles of the rotor 41 and the stator 60. In Fig. 3, the radially outer side of the figure shown as the stator 60 corresponds to the upper side of the stator 60, and the radially inner side corresponds to the lower side.

[0034] The rotor 41 has a cylindrical shape. The outer diameter of the rotor 41 is slightly smaller than the inner diameter of the can 20. The rotor 41 is disposed 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 disposed on the outer peripheral 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 alternately disposed at equal angular intervals in the circumferential direction. The rotor 41 has, for example, 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 an axial 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 formed on the outer circumferential surface of the valve stem holder 42. The second axial portion 32 of the valve element 30 is disposed in the axial hole 42b, and the second axial portion 32 is movable up and down within the axial hole 42b. A valve-closing spring 47 is disposed between a washer 46 disposed on the lower surface of the upper wall portion 42a of the valve stem holder 42 and the step portion 34 of the valve element 30. The valve-closing spring 47 is a coil spring and presses the valve element 30 toward the valve seat 18. A female thread 42c is formed 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 peripheral surface of the support portion 43b. The male thread 43c is threadedly engaged with the female thread 42c of the valve stem holder 42. The first shaft portion 31 of the valve element 30 is disposed inside the guide bush 43. The guide bush 43 supports the valve element 30 so that it can move in the direction of the axis L.

[0037] The stopper member 44 has a cylindrical shape. The stopper member 44 is fixed to the lower end of the support portion 43b of the guide bush 43. A fixed stopper 44s is integrally provided on the outer 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 fixed portion 45a and a flange portion 45b. The fixed portion 45a has a stepped cylindrical shape. The second shaft portion 32 of the valve body 30 is disposed inside the fixed portion 45a. The fixed portion 45a is joined to the second shaft portion 32. The flange portion 45b is connected to the lower end of the fixed portion 45a. A return spring 48 is disposed outside the retaining member 45. The return spring 48 is a coil spring.

[0039] The motor-operated valve 5 has a drive mechanism 40 that uses the rotation of the rotor 41 without reducing the speed. The motor-operated valve 5 may have a drive mechanism that has a speed reduction mechanism that reduces the speed of the rotation of the rotor 41, instead of the drive mechanism 40.

[0040] The stator 60 has a cylindrical shape and 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 pole teeth 61a, 61b are arranged on the inner periphery of the yoke. The tips of the pole teeth 61a face downward, and the tips of the pole teeth 61b face upward. The pole teeth 61a and 61b are alternately arranged at equal angular intervals in the circumferential direction. The A-phase stack 61 has, for example, 12 pole teeth 61a and 12 pole teeth 61b. The angle between adjacent pole teeth 61a and 61b is 15 degrees. The A-phase stack 61 has an A-phase coil 61c. The A-phase coil 61c is wound around a cylindrical bobbin and housed in the yoke together with the bobbin. The A-phase coil 61c is indirectly in contact with the yoke via the bobbin. Note that 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 of mutually opposite polarities.

[0042] The B-phase stack 62 has a hollow, annular yoke, and multiple claw-pole pole teeth 62a, 62b are arranged on the inner periphery of the yoke. The tips of the pole teeth 62a face downward, and the tips of the pole teeth 62b face upward. The pole teeth 62a and 62b are alternately arranged at equal angular intervals in the circumferential direction. The B-phase stack 62 has, for example, 12 pole teeth 62a and 12 pole teeth 62b. The angle between adjacent pole teeth 62a and 62b is 15 degrees. The B-phase stack 62 has a B-phase coil 62c. The B-phase coil 62c is wound around 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. Note that the B-phase coil 62c may be in direct contact with the yoke as long as 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 polarities. The B-phase stack 62 has the same configuration as the A-phase stack 61.

[0043] The A-phase stack 61 is coaxially disposed on the B-phase stack 62. The B-phase stack 62 is located at a position rotated 7.5 degrees around the axis L with respect to the A-phase stack 61 from the position where the pole teeth 61 a and the pole teeth 62 a are aligned in the direction of the axis L.

[0044] The can 20 is disposed inside the stator 60, and the yoke of the A-phase stack 61 and the yoke of the B-phase stack 62 are in contact with the outer circumferential surface of the can 20. The rotor 41 is disposed inside the can 20. The stator 60 and the rotor 41 form 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 by a two-phase excitation method. Pulses P (P[1] to P[4]) are input to the stepping motor 66, causing the rotor 41 to rotate. Specifically, a drive current corresponding to the pulses P is supplied to the stator 60 of the stepping motor 66, causing the rotor 41 to rotate. In this specification, "inputting pulses P to the stepping motor 66" is synonymous with "supplying a drive current corresponding to the pulses P to the stator 60 of the stepping motor 66." Note that the stepping motor 66 may also be controlled by a one-phase excitation method, a one-two-phase excitation method, a W1-2-phase excitation method, a two-phase excitation method, or a four-phase excitation method.

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

[0047] 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. The magnetic poles of the rotor 41 and the stator 60 are also shown in FIGS. 4 to 7. In FIGS. 4 to 7, to make it easier to understand the positional relationship between the rotor 41 and the stator 60 (the A-phase stack 61 and the B-phase stack 62), the reference pole tooth 61a and the reference magnetic pole (south pole) of the rotor 41 are indicated by black circles.

[0048] When pulses P are cyclically input to the stepping motor 66 in ascending order and the rotor 41 rotates in the first direction, the rotor 41 and the valve 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 presses the valve element 30 downward via the valve closing spring 47. The valve element 30 moves downward, and the valve portion 33 contacts the valve seat 18. The rotor 41 is in the valve closing position Rc at this time. When the rotor 41 is further rotated in the first direction from this state, the valve closing spring 47 is compressed, and the rotor 41 and the valve stem holder 42 move further downward. The valve element 30 does not move downward. When the movable stopper 42s contacts the fixed stopper 44s, rotation of the rotor 41 in the first direction is restricted. The rotor 41 is in the reference position Rx at this time. The movable stopper 42s and the fixed stopper 44s form 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 cyclically input to the stepping motor 66 in descending order and the rotor 41 rotates in the second direction, the rotor 41 and the valve 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 disc 30 moves upward together with the retaining member 45, and the valve disc 30 separates from the valve seat 18. The position of the rotor 41 when the flow rate of the fluid at the valve port 17 (opening of the valve port 17) is a predetermined set value in a predetermined flow measurement environment is defined as the open position Ro. The set value is set appropriately depending on the configuration and application of the motor-operated valve device 1. When the rotor 41 rotates in the second direction and reaches the fully open position Rz, the valve disc 30 is farthest from the valve port 17, and the valve port 17 is at its maximum opening.

[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 the stroke number Ns are input to the stepping motor 66 of the motor-operated valve 5 with the rotor 41 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, can 20, valve body 30, rotor 41, valve shaft holder 42, guide bush 43, and stator 60 (A-phase stack 61 and B-phase stack 62) each have a central axis that coincides with the axis L.

[0052] The motor-operated valve control device 70 has a substrate 71 on which a plurality of electronic components (not shown) are mounted. As shown in Fig. 1, the motor-operated valve control device 70 has a non-volatile memory 75, a communication device 76, a motor driver 77, and a computer 80. The motor-operated valve control device 70 controls the motor-operated valve 5 based on commands from the air conditioner control device 110.

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

[0054] The communication device 76 is communicably connected to the air conditioner control device 110 via a wired communication bus 120. 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 wirelessly.

[0055] 8 is a diagram schematically showing a computer 80, a motor driver 77, and a stepping motor 66 included in the electrically operated valve control device 70. The motor driver 77 is connected to the A-phase coil 61 c and the B-phase coil 62 c 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 currents (A-phase current Ia and B-phase current Ib) to the stator 60 to rotate the rotor 41. 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. The motor driver 77 is a current supply device.

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

[0058] Furthermore, a current control signal (CONTROL) is input to the motor driver 77 from the computer 80. The current control signal is a signal for setting, in the motor driver 77, an A-phase current target value and a B-phase current target value, which are target values ​​for the A-phase current Ia and the B-phase current Ib.

[0059] FIG. 10 shows an example of the correspondence relationship between pulse P and the A-phase current target value and B-phase current target value. 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" have the same current magnitude but different current directions. The target value (It) is, for example, 200 to 600 mA.

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

[0061] 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 using a full-step method. The step angle of the stepping motor 66 is 7.5 degrees. The stepping motor 66 may also be controlled using a half-step method or a micro-step method.

[0063] The motor driver 77 has H-bridge circuits 77 A and 77 B and a current control section 77 C. 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 includes switches SW11, SW12, SW13, and SW14. The upstream end of the H-bridge circuit 77A is connected to a 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 includes switches SW21, SW22, SW23, and SW24. The upstream end of the H-bridge circuit 77B is connected to a power supply, and the downstream end of the H-bridge circuit 77B is connected to the reference potential of the circuit board 71 via a shunt resistor 78B. The switches SW11, SW12, SW13, and SW14 and the switches SW21, SW22, SW23, and SW24 are, for example, N-channel MOSFETs or P-channel MOSFETs, or a combination of both.

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

[0066] The current control section 77C controls the H-bridge circuits 77A and 77B by pulse width modulation (PWM) in response to 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 the switches SW12 and SW13. (2) The current control unit 77C controls the on-time (i.e., duty cycle) of the switches SW11 and SW14 so that the magnitude of the A-phase current Ia is the same as the magnitude of the A-phase current target value.

[0068] When supplying the A-phase current Ia flowing from terminal A2 to terminal A1 to the A-phase coil 61c: (1) The current control unit 77C turns off the switches SW11 and SW14. (2) The current control unit 77C controls the on-time of the 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 flowing from terminal B1 to terminal B2 to the B-phase coil 62c: (1) The current control unit 77C turns off the switches SW22 and SW23. (2) The current control unit 77C controls the on-time of the 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 flowing from terminal B2 to terminal B1 to the B-phase coil 62c: (1) The current control unit 77C turns off the switches SW21 and SW24. (2) The current control unit 77C controls the on-time of the 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 the B-phase current Ib are currents controlled (constant current driven) by pulse width modulation so that they reach their target values. Each switch is turned on / off at a time interval shorter than the period of the pulse P so that the A-phase current Ia and the B-phase current Ib reach their respective target values.

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

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

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

[0076] The rotation control unit 81 inputs pulses P to the stepping motor 66 to rotate the rotor 41 in a first direction or a second direction. Specifically, the rotation control unit 81 controls the motor driver 77 based on a command from the air conditioner control device 110 to supply an A-phase current Ia to the A-phase coil 61c and a 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 a change period during which the A-phase current Ia flowing through the A-phase coil 61c changes from a first current value to a second current value. The acquisition unit 82 may also acquire information relating to a change period during which the B-phase current Ib flowing through the B-phase coil 62c changes from the first current value to the second current value. Examples of the information relating to the change period are shown below.

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

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

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

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

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

[0083] 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 FIGS. 12 and 13 include the drive current waveform during the rise period. FIG. 12 shows the drive current waveform when the temperature T of the rotor 41 (temperature of the thermostatic bath) is -30°C. FIG. 13 shows the drive current waveform 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 tends to be the same 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. Note that, like the rise period, the temperature T of the rotor 41 can also be estimated using the fall time. Figure 15 shows the change time rt (rise time) from the beginning to the end of the rise period of the A-phase current Ia and the change time ft (fall time) from the beginning to the end of the fall period.

[0085] Furthermore, as shown in FIG. 12 , when the temperature T of the rotor 41 is low, the slope of the rising waveform is relatively large. As shown in FIG. 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 times 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 waveform and duty cycle of the drive current during a determination period E, which includes a rising period (change period). Figure 16 shows the waveform of the drive current when the temperature T of the rotor 41 is low. Figure 17 shows the waveform of the drive current when the temperature T of the rotor 41 is high. "Including the change period" means "including at least a portion of the change period." It is sufficient that the determination period E includes a portion of the change period to the extent that the temperature T of the rotor 41 can be estimated.

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

[0088] 18 shows the waveform of the drive current during the determination period E, which includes the rise period (change period). In FIG. 18, the dashed dotted 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 determination period E, which includes the rise period.

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

[0090] In the motor-operated valve 5, a 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 temperature of the refrigerant is low, the viscosity of the refrigerant oil is high, making it difficult for the rotor 41 to rotate. When the temperature of the refrigerant 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 with difficulty.

[0092] For this reason, 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 according to the temperature T of the rotor 41 to the coil of the stator 60, the stepping motor 66 can output torque equal to or greater than the specified value without consuming extra 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 (room temperature state), the rotation control unit 81 sets the room 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 TL of the operating temperature range of the motor-operated valve 5, the second temperature determination value T2 is less than the upper limit TH of the operating temperature range of the motor-operated 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 room temperature target value ItR, the high temperature target value ItH is greater than the room 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 room temperature target value ItR, and the high temperature target value ItH are set appropriately depending on the configuration of the motor-operated valve device 1, etc.

[0096] When the electric valve control device 70 (computer 80) is powered on, it reads out the position of the rotor 41 stored in the nonvolatile memory 75 as the current position Rp of the rotor 41. When the electric valve control device 70 receives a valve element movement command including a target valve opening from the air conditioner control device 110, it performs a valve element movement operation. The valve element movement operation is an operation in which the rotor 41 is rotated from the current position Rp to a position corresponding to the target valve opening, and that position is set as the new current position Rp. The electric valve control device 70 stores the current position Rp in the nonvolatile memory 75 immediately before the power is cut off.

[0097] The motor-operated valve control device 70 performs a drive current setting operation in parallel with the valve element moving operation. Examples of the drive current setting operation (first operation example to third operation example) are shown in Figures 20 to 22.

[0098] A first operation example of the motor-operated valve control device 70 will be described with reference to FIG.

[0099] The motor-operated 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 the pulses P of the distance determination number F is defined as the travel distance M. The travel distance M is the rotation angle of the rotor 41 when the pulses P of the distance determination number F are input to the stepping motor 66. The distance determination number F is, for example, 50. (1) When the distance (rotation angle) between the current position Rp of the rotor 41 and the reference position Rx is equal to or less than the travel distance M, the motor-operated valve control device 70 determines that the current position Rp of the rotor 41 is not within the temperature estimation range. (2) When the distance between the current position Rp of the rotor 41 and the fully open position Rz is equal to or less than the travel distance M, the motor-operated valve control device 70 determines that the current position Rp of the rotor 41 is not within the temperature estimation range. (3) When conditions (1) and (2) are not met, the motor-operated valve control device 70 determines that the current position Rp of the rotor 41 is within the temperature estimation range. The temperature estimation range includes positions of the rotor 41 from the reference position Rx to the fully open position Rz, excluding (i) positions within the moving distance M from the reference position Rx, and (ii) positions within the moving distance M from the fully open position Rz.

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

[0102] When the motor-operated 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 an average value Ka of a plurality of rise times of the drive current supplied to the coil of the stator 60 (S120). Specifically, the motor-operated valve control device 70 acquires the rise time of the A-phase current Ia, and calculates the average value Ka of the rise times of the target number G of acquisition times. The target number G is, for example, 10, which is a number equal to or less than the distance determination number F.

[0103] The motor-operated valve control device 70 estimates the temperature T of the rotor 41 using the average value Ka (S130). For example, a data table (temperature table) containing a plurality of pairs of average values ​​Ka and temperatures T of the rotor 41 corresponding to the average values ​​Ka is stored in the non-volatile memory 75, and the motor-operated valve control device 70 reads out the temperature T of the rotor 41 corresponding to the calculated average value Ka from the temperature table. In other words, the motor-operated 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 based on, for example, actual measurements or simulation results.

[0104] When the temperature T of the rotor 41 is lower than the first temperature determination value T1 (Y in S140: low temperature state), 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 equal to or greater than 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] When the temperature T of the rotor 41 is equal to or greater than the first temperature determination value T1 and equal to or less than the second temperature determination value T2 (N in S140, N in S160: room temperature state), the electric valve control device 70 sets the room temperature target value ItR as the magnitude of the target value of the drive current (S180) and terminates this operation.

[0107] The motor-operated valve control device 70 may estimate the temperature T of the rotor 41 using the slope of the waveform of the A-phase current Ia. Specifically, the motor-operated valve control device 70 calculates the slope using multiple A-phase currents Ia (current values) acquired at different times during the rise period, and calculates the average value of the multiple slopes. The motor-operated valve control device 70 then uses the average value to acquire the temperature T of the rotor 41 from a temperature table (containing multiple pairs of the average value and the temperature T of the rotor 41 corresponding to the average value) stored in the non-volatile memory 75.

[0108] Next, a second operation example of the motor-operated valve control device 70 will be described with reference to FIG.

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

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

[0111] When the motor-operated 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 an average value Daa of multiple duty cycles of the drive current supplied to the coil of the stator 60 (S220). Specifically, the motor-operated valve control device 70 obtains multiple duty cycles of the A-phase current Ia during a determination period E that includes the rise period, and calculates the average value Da of the multiple duty cycles. After calculating the average value Da of the acquisition target number G, the motor-operated valve control device 70 calculates the average value Daa of these duty cycles.

[0112] The motor-operated valve control device 70 estimates the temperature T of the rotor 41 using the average value Daa (S230). For example, a temperature table containing a plurality of pairs of the average value Daa and the temperature T of the rotor 41 corresponding to the average value Daa is stored in the non-volatile memory 75, and the motor-operated valve control device 70 reads out the temperature T of the rotor 41 corresponding to the calculated average value Daa from the temperature table. In other words, the motor-operated 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 of steps S210, and S240 to S280 are the same as the operations of steps S110, and S140 to S180 in Fig. 20. A description of the operations of steps S210, and S240 to S280 will be omitted.

[0114] The motor-operated valve control device 70 may estimate the temperature T of the rotor 41 using the number of 100% duty cycles among the multiple duty cycles of the A-phase current Ia. Specifically, the motor-operated valve control device 70 counts the number of 100% duty cycles among the multiple duty cycles of the A-phase current Ia during the determination period E and calculates the average value of the multiple counts. Then, the motor-operated valve control device 70 uses the average value to obtain the temperature T of the rotor 41 from a temperature table (containing multiple pairs of the average value and the temperature T of the rotor 41 corresponding to the average value) stored in the non-volatile memory 75.

[0115] Next, a third operation example of the motor-operated valve control device 70 will be described with reference to FIG.

[0116] First, the dissimilarity index value sv used in the third operation example will be described.

[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 motor-operated valve control device 70 calculates the difference index value sv.

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

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

[0120] The reference waveform of the A-phase current Ia is set, for example, based on the waveform of the A-phase current Ia when the temperature T of the rotor 41 is −30° C. A reference waveform of the A-phase current Ia used when the rotor 41 is rotating in a first direction and a reference waveform of the A-phase current Ia used when the rotor 41 is rotating in a second direction are separately prepared. The reference waveform of the A-phase current Ia is stored in the non-volatile memory 75 during manufacture of the motor-operated 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, times tc at predetermined intervals from the start of the determination period E (time 0) are associated with the reference current value ir at that time tc. The interval between times tc is the same as the sampling period (100 μs). One waveform table has 40 pairs of times tc and reference current values ​​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 motor-operated valve control device 70 acquires the current value ia at acquisition time t, it reads out from the waveform table the reference current value ir associated with time tc corresponding to the acquisition time t. The motor-operated valve control device 70 calculates a value (difference value dv) by subtracting the reference current value ir from the current value ia. The motor-operated valve control device 70 calculates a value (intermediate value dv2) by squaring the difference value dv. The motor-operated valve control device 70 calculates a dissimilarity index value sv by adding together multiple intermediate values ​​dv2 calculated corresponding to one determination 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 ia[t], and the reference current value ir associated with time tc corresponding to the acquisition time t in the waveform table is ir[t], the dissimilarity index value sv is expressed by the following equation (1):

[0124]

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

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

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

[0128] When the motor-operated 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 an average value sva of multiple discrepancy index values ​​sv related to the drive current supplied to the coil of the stator 60 (S320). Specifically, the motor-operated valve control device 70 acquires the waveform of the A-phase current Ia during a determination period E, including the rise period, and calculates the discrepancy index value sv. After calculating the discrepancy index values ​​sv for the target number G of acquisitions, the motor-operated valve control device 70 calculates the 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° C. Therefore, if the average value sva is small, the temperature T of the rotor 41 is estimated to be low, and if the average value sva is large, the temperature T of the rotor 41 is estimated to be high.

[0129] The motor-operated valve control device 70 estimates the temperature T of the rotor 41 using the average value sva (S330). Specifically, a temperature table containing a plurality of pairs of the average value sva and the temperature T of the rotor 41 corresponding to the average value sva is stored in the non-volatile memory 75, and the motor-operated valve control device 70 reads out the temperature T of the rotor 41 corresponding to the calculated average value sva from the temperature table. In other words, the motor-operated 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 of steps S310, and S340 to S380 are the same as the operations of steps S110, and S140 to S180 in Fig. 20. A description of the operations of steps S310, and S340 to S380 will be omitted.

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

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

[0133] As described above, the motor-operated valve device 1 includes the motor-operated valve 5 and the motor-operated valve control device 70. The motor-operated valve 5 includes the valve body 10 having the valve chamber 14 and the valve port 17, the cylindrical can 20 attached to the valve body 10, the rotor 41 disposed in the inner space 21 of the can 20, the stator 60, and the valve element 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 that contacts the outer circumferential surface of the can 20 and coils (A-phase coil 61c, B-phase coil 62c) housed in the yoke. Drive currents (A-phase current Ia, B-phase current Ib) for rotating the rotor 41 are supplied to the coils. The motor-operated valve control device 70 includes a computer 80 that estimates the temperature T of the rotor 41 based on the drive current flowing through the coils.

[0134] In the motor-operated valve 5, the valve chamber 14 and the inner space 21 of the can 20 are connected, and the refrigerant in 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, via the can 20 and yoke, in the temperature of the coil. There is a relationship between the temperature of the coil and the temperature T of the rotor 41, and the current flowing through the coil is also related to the temperature T of the rotor 41. As a result, the temperature T of the rotor 41 can be estimated with high accuracy using a motor-operated valve control device 70 with a simple configuration.

[0135] The computer 80 also estimates the temperature T of the rotor 41 using information related to a rise period during which the drive current flowing through the coil changes from a first current value to a second current value. The information related to the rise period is the time period (rise time) during which the drive current changes from the beginning to the end of the rise period (first operation example). The information related to the rise period is the duty cycle of the pulse width modulation method during a determination period E that includes the rise period (second operation example). Alternatively, the information related to the rise period is the degree of difference between the waveform of the drive current flowing through the coil during the determination period E that includes the rise period and a reference waveform of the drive current (third operation example). The information related 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 manner, the motor-operated valve control device 70 can estimate the temperature T of the rotor 41 based on information that is relatively easy to obtain.

[0136] Furthermore, the coil of the stator 60 is connected to a motor driver 77. A 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 coil. This allows the stepping motor 66 to output torque equal to or greater than the specified value without consuming extra power.

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

[0138] The motor-operated valve control device 70 may autonomously perform the drive current setting operation. For example, the motor-operated valve control device 70 performs the drive current setting operation when power is turned on or when a predetermined time (e.g., one hour) has elapsed since the previous drive current setting operation. In this drive current setting operation, the motor-operated 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 motor-operated valve control device 70 supplies a drive current corresponding to the pulse P to the coil. For example, when pulse P[1] corresponds to the current position Rp of the rotor 41, the motor-operated 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 motor-operated 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 motor-operated 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 the current position Rp. The pulse P corresponding to the current position Rp of the rotor 41 is also the pulse P last input to the stepping motor 66.

[0139] The motor-operated valve control device 70 may perform the following operation. After power is applied, the motor-operated valve control device 70 estimates the temperature T of the rotor 41. When the temperature T of the rotor 41 is lower than an operating temperature determination value (e.g., 25°C), the motor-operated valve control device 70 supplies a current to the coil via the motor driver 77 to raise the temperature T of the rotor 41. This causes the coil to generate heat, which in turn heats the refrigerant in the can 20 and its internal space 21 and the rotor 41. The motor-operated 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 motor-operated valve control device 70 supplies a drive current corresponding to the pulse P to the coil. As a result, the motor-operated valve control device 70 estimates the temperature T of the rotor 41 based on the current flowing through the coil while keeping the rotor 41 at the current position Rp, and supplies a current to the coil to raise the temperature T of the rotor 41. The motor-operated 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 judgment value. Before estimating the temperature T of the rotor 41, the motor-operated valve control device 70 waits to supply current to the coil until the temperature of the coil, which has been increased by the current, drops to a temperature suitable for estimation. In this way, the motor-operated valve control device 70 can increase the temperature T of the rotor 41 to a temperature suitable for operation of the stepping motor 66. The operating temperature judgment value is set appropriately depending on the configuration of the motor-operated valve device 1.

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

[0141] The motor-operated valve control device 70 may have a temperature sensor. The temperature sensor is mounted on the substrate 71 and connected to the computer 80. The temperature sensor may be built into the computer 80. The stator 60 and substrate 71 are housed, for example, in 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 disposed). The inner space is a closed space. An example (fourth operation example) of the operation of the motor-operated valve control device 70 having this configuration will be described with reference to FIG. 23 . The motor-operated valve control device 70 performs this operation immediately after power is turned on.

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

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

[0144] The motor-operated 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 motor-operated valve control device 70 sets the normal temperature target value ItR as the magnitude of the target value of the drive current (S470) and ends this operation.

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

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

[0148] In this way, the motor-operated 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. The motor-operated valve control device 70 may set the room temperature target value ItR as the magnitude of the target value of the drive current after a predetermined time (e.g., one hour) has elapsed since performing this operation. The motor-operated valve control device 70 may also perform this operation at predetermined time intervals (e.g., every hour) after power is turned on.

[0149] In this specification, terms indicating a shape, such as "cylinder" or "column," are also used to refer to members or portions of members that substantially have the shape of the term. For example, a "cylindrical member" includes both a cylindrical member and a substantially cylindrical member. In addition, in this specification, the term "same" can include both the exact same and the substantially same.

[0150] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Any modifications, additions, deletions, or design changes of components made by a person skilled in the art to the above embodiments, or any combinations of features of the embodiments, are also included within the scope of the present invention as long as they do not deviate from the spirit of the present invention.

[0151] 1...motor-operated valve device, 5...motor-operated 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 stem 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...motor-operated valve control device, 75...non-volatile memory, 76...communication device, 77...motor driver, 80...computer

Claims

1. An electric valve control device that controls an electric valve having a valve body with 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 placed in the inner space, a hollow annular yoke in contact with the outer surface of the case and a stator having a coil housed in the yoke, and a valve disc that faces the valve port in the valve chamber and moves relative to the valve port when the rotor rotates, wherein a drive current for rotating the rotor is supplied to the coil, and characterized by having a processing device that estimates the temperature of the rotor based on the current flowing through the coil.

2. The motor-operated valve control device according to claim 1, wherein the drive current is a current that alternates between a first current value and a second current value, and the processing device estimates the temperature of the rotor using information relating to the period of time during which the current flowing through the coil changes from the first current value to the second current value.

3. The motor-operated valve control device according to claim 2, wherein the information relating to the change period is a change time from the start to the end of the change period.

4. The motor-operated valve control device according to claim 2, wherein the current is controlled by pulse width modulation, and the information relating to the change period is a duty cycle of the pulse width modulation during a determination period that includes the change period.

5. The motor-operated valve control device according to claim 2, wherein the information relating to the change period is the degree of difference between the waveform of the current flowing through the coil during a determination period including the change period and a reference waveform of the current.

6. The motor-operated valve control device according to claim 2, 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.

7. The motor-operated valve control device according to claim 1, wherein the coil is connected to a current supply device, and the processing device controls the current supply device so that the drive current having a magnitude corresponding to the temperature of the rotor is supplied to the coil.

8. The motor-operated valve control device according to claim 1, wherein 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 an operating temperature determination value, a current for raising the temperature of the rotor is supplied to the coil.

9. The motor-operated valve control device according to claim 1, wherein the motor-operated valve is incorporated into a refrigeration cycle system and is used to control the flow rate of a refrigerant, the processing device estimates the temperature of the rotor after a waiting time has elapsed since the refrigeration cycle system was stopped, and the waiting time is set to a length that eliminates the temperature difference between the rotor and the coil.

10. The motor-operated valve control device according to claim 1, wherein the coil is connected to a current supply device, the motor-operated valve control device has a temperature sensor that outputs a signal according to the temperature of the space in which the stator is disposed, and 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 magnitude of the drive current is supplied to the coil when the temperature of the rotor is higher than a rotor temperature determination value or the temperature of the space is higher than a space temperature determination value, and controls the current supply device so that a drive current larger than the normal magnitude is supplied to the coil when the temperature of the rotor is equal to or lower than the rotor temperature determination value and the temperature of the space is equal to or lower than the space temperature determination value.

11. The motor-operated valve control device according to claim 10, wherein the motor-operated valve has a housing that houses the stator and the temperature sensor.

12. A motor-operated valve device comprising the motor-operated valve and the motor-operated valve control device according to claim 1.

13. A control method for an electrically operated 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 placed in the inner space, a hollow annular yoke in contact with the outer surface of the case and a stator having a coil housed in the yoke, and a valve disc facing the valve port in the valve chamber and moving relative to the valve port as the rotor rotates, wherein a drive current for rotating the rotor is supplied to the coil, the control method for an electrically operated valve comprising: estimating the temperature of the rotor based on the current flowing through the coil; and supplying the drive current to the coil at a magnitude corresponding to the temperature of the rotor.

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