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

Abstract

To provide a motor-operated valve control device capable of detecting a load on a motor and a state of a motor-operated valve with a high degree of accuracy.SOLUTION: A motor-operated valve control device comprises a load determination part 91 that controls a motor-operated valve having a magnet rotor for opening / closing a valve port and a stepping motor including a coil part for rotating the magnet rotor. The load determination part 91 determines a load on the stepping motor on the basis of a phase difference between an exciting current or an exciting voltage supplied to the coil part and a counter-electromotive force generated in a non-energization phase in the coil part.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an electric valve control device, an electric valve device, and an electric valve control method, and more particularly to a technique for controlling an electric valve that opens and closes a valve port by a rotor rotated by a motor. [Background technology]

[0002] Motor-operated valves are used in the refrigerant flow path of air conditioners, for example, and control the flow rate of the refrigerant by the opening of the valve port. The opening of the valve port is controlled by the rotation amount of the rotor in the motor. The motor is controlled using an excitation voltage applied to the motor and a back electromotive voltage (induced voltage) generated in the stator, and a process is performed to detect the load on the motor and, ultimately, the state of the motor-operated valve. A stepping motor driving method that monitors the motor load and detects loss of synchronization of the motor-operated valve device is described, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-17598 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the stepping motor driving method described in Patent Document 1 detects the load state of the motor by calculating the differential voltage between the coil voltage of the stepping motor and a predicted coil voltage corresponding to the rotational speed of the stepping motor and comparing the differential voltage with a threshold value. With the configuration described in Patent Document 1, the rotational speed of the stepping motor depends on the coil voltage, so both the coil voltage and the predicted coil voltage change, and there is a problem in further improving the accuracy of the differential voltage compared with the threshold value.

[0005] The present invention has been made in consideration of the above points, and aims to provide an electric valve control device, an electric valve device, and an electric valve control method that can detect the load on the motor and the state of the electric valve with high accuracy. [Means for solving the problem]

[0006] One aspect of the present invention is an electric valve control device that includes an electric valve control unit that controls an electric valve that has a rotor that opens and closes a valve port and a motor that includes a coil unit that rotates the rotor, and the electric valve control unit includes a load determination unit that determines the load on the motor based on the phase difference between the excitation voltage or excitation current supplied to the coil unit and the back electromotive force generated in the non-energized phase in the coil unit.

[0007] Another aspect of the present invention is an electric valve device including the above-described electric valve control device.

[0008] Another aspect of the present invention is a method for controlling an electric valve having a rotor that opens and closes a valve port and a motor that includes a coil unit that rotates the rotor, the method including the steps of: acquiring an excitation voltage or excitation current supplied to the coil unit and a back electromotive force generated in the coil unit in a non-energized phase; calculating a phase difference between the phase of the acquired excitation voltage or excitation current and the phase of the back electromotive force; and a load determination unit that determines a load on the motor based on the phase difference. [Effects of the Invention]

[0009] According to the above aspects, it is possible to provide an electric valve control device, an electric valve device, and an electric valve control method that can detect the load on the motor and the state of the electric valve with high accuracy. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a system to which an electric valve device according to an embodiment of the present invention is applied; [Figure 2]1 is a diagram illustrating an electric valve device according to an embodiment of the present invention; [Figure 3] 3 is a diagram for explaining an upper limit stopper and a lower limit stopper of the guide system shown in FIG. 2. FIG. [Figure 4] FIG. 3 is a cross-sectional view of a coil portion of the motor-operated valve shown in FIG. 2. [Figure 5] FIG. 2 is a functional block diagram of the motor-operated valve control device shown in FIG. [Figure 6] 3 is a diagram illustrating an example of a threshold value for determining whether the valve port shown in FIG. 2 is fully closed or fully open. [Figure 7] 4 is a flowchart illustrating an initialization process according to the first embodiment. [Figure 8] FIG. 10 is a diagram for explaining part initialization according to the second embodiment of the present invention. [Figure 9] 10 is a flowchart illustrating an initialization process according to the second embodiment. [Figure 10] 10A and 10B are diagrams for explaining types of step-out detected by the third embodiment. [Figure 11] 10 is a flowchart illustrating a lock determination process according to the third embodiment. [Figure 12] 10 is a flowchart illustrating a known initialization process. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a first embodiment and a second embodiment of the present invention (hereinafter also collectively referred to as "the present embodiment") will be described with reference to the drawings. The drawings used to describe the present embodiment are intended to explain the configuration of the present invention, the positional relationship of each configuration, effects, operation, technical concept, etc., and are not intended to limit the specific specifications or shape of the present invention.

[0012] (First embodiment) 1 is a diagram illustrating a system to which an electric valve device 100 of this embodiment is applied. The system includes, for example, a circulation mechanism 5 that circulates a refrigerant in an air conditioner, an electric valve 1 applied to the circulation mechanism 5, an electric valve control device 2 that controls the electric valve 1, and a system control device 58 that performs overall control of the system based on, for example, an operation signal. The electric valve 1 and the electric valve control device 2 constitute the electric valve device 100.

[0013] The circulation mechanism 5 includes a heat exchanger OUT51, a heat exchanger IN52, a four-way valve 53, and a compressor 54. The heat exchanger OUT51 functions as a condenser for the outdoor unit during cooling and as an evaporator for the outdoor unit during heating. Similarly, the heat exchanger IN52 functions as an evaporator for the indoor unit during cooling and as a condenser for the indoor unit during heating. The four-way valve 53 switches the direction of refrigerant flow between cooling and heating. The motor-operated valve 1 is an expansion valve. The system control device 58 is communicatively connected to the motor-operated valve device 100. The system control device 58 uses the motor-operated valve device 100 to control the flow rate of refrigerant flowing through the piping.

[0014] The motor-operated valve 1 according to this embodiment will be described with reference to Figure 2. The motor-operated valve 1 is mainly composed of a valve body 10, a support member 70, a drive shaft 55, a valve body 60, a coil member 30, and a stepping motor 80. Each component of the motor-operated valve 1 will be described below in order.

[0015] The valve body 10 is formed in a cylindrical shape from a metal such as stainless steel. A valve seat member 23 formed separately from the valve body 10 is provided to close the lower end of the valve body 10. A valve port 22 that functions as a valve opening is opened in the center of the valve seat member 23. The valve body 10 forms a valve chamber 14 inside.

[0016] A first coupling pipe 18, which serves as a flow path for a fluid such as a refrigerant, is connected to one outer periphery of the valve body 10, and this first coupling pipe 18 is in communication with the valve chamber 14. A second coupling pipe 28, which abuts against a valve seat member 23, is connected to the bottom side of the valve body 10, and this second coupling pipe 28 is in communication with the valve chamber 14 via a valve port 22. The first coupling pipe 18 and the second coupling pipe 28 are made of, for example, copper or stainless steel, and are fixed to the valve body 10 by brazing or the like.

[0017] The case 86 is made of a metal such as stainless steel and has a generally cylindrical shape with a closed upper end. The lower open end of the case 86 is airtightly fixed to the upper end of the valve body 10 by welding or the like.

[0018] The support member 70 includes a substantially cylindrical holder portion 50 made of a resin material such as polyphenylene sulfide (PPS), and a stainless steel fixing portion 79 that is integrally provided by insert molding on the end of the holder portion 50 that is closer to the valve body 10. The support member 70 is fixed to the valve body 10 by the fixing portion 79 through welding.

[0019] The holder portion 50 is disposed so that its axis overlaps with the axis L passing through the axis of the valve port 22. A drive shaft 55 is inserted through the center of the holder portion 50, and the male thread portion 55a of the drive shaft 55 threadably engages with the female thread portion 50b on the inner surface of the holder portion 50. A guide rail 75 consisting of a spiral ridge is integrally formed on the outer circumferential surface of the holder portion 50. Adjacent winding portions of the guide rail 75 are disposed with a gap between them. The guide rail 75 is disposed so that its axis overlaps with the axis L, and the winding portion 31 (described later) is threadably engaged with the guide rail 75, guiding each winding portion of the winding portion 31 from one or both sides so that the winding portion 31 can rotate in the circumferential direction.

[0020] The drive shaft 55 is formed into a cylindrical rod shape using a metal such as stainless steel. The drive shaft 55 is formed with a male thread portion 55a, a guide portion 56, and a flange portion 57 arranged at the end of the guide portion 56 closer to the valve port 22, which are aligned in the direction of the axis L. The male thread portion 55a is threadedly engaged with a female thread portion 50b on the inner surface of the holder portion 50, thereby converting the rotational motion of the drive shaft 55 into linear motion. The guide portion 56 is slidably engaged with the inner circumferential surface of the bearing hole 56a, thereby guiding the movement of the drive shaft 55 in the direction of the axis L.

[0021] The valve body portion 60 includes a valve holder 61 , a valve body 42 , a washer 63 , a spring bearing 41 , and a compression coil spring 43 .

[0022] The valve holder 61 is formed in a cylindrical shape with an outer diameter that is approximately the same as the inner diameter of the slide hole 56b through which the guide portion 56 of the holder part 50 is inserted. The valve holder 61 is engaged so as to be slidable in the direction of the axis L along the slide hole 56b.

[0023] The valve element 42 is needle-shaped and is fixed to the lower end 40a of the valve holder 61 on the valve port 22 side so that the tip of the needle faces the valve port 22. The valve element 42 adjusts the flow rate by adjusting the opening between the valve element 42 and the valve seat of the valve port 22 between the maximum valve opening and the minimum valve opening (or fully closed state).

[0024] A flange portion 57 of the drive shaft 55 is rotatably engaged with the upper end portion 40b of the valve holder 61 on the side opposite the valve port 22. Specifically, a washer 63 is sandwiched between the flange portion 57 of the drive shaft 55 and the upper end portion 40b of the valve holder 61, and the drive shaft 55 is rotatably engaged with the upper end portion 40b of the valve holder 61 by this flange portion 57. Due to this engagement, the valve holder 61 is supported by the drive shaft 55 so as to be movable in the direction of axis L and rotatable about axis L. An opening larger than the radial movement range of the drive shaft 55 is formed in the upper end portion 40b of the valve holder 61. A spring retainer 41 is provided within the valve holder 61 so as to be movable in the direction of axis L. A compression coil spring 43 is attached between the spring retainer 41 and the valve body 42 in a compressed state with a predetermined load applied. As a result, the spring bearing 41 is pressed against the drive shaft 55 and comes into contact with the end face of the drive shaft 55 on the flange portion 57 side.

[0025] The coil member 30 integrally includes a coil spring-shaped winding portion 31 and a claw portion 32 protruding radially outward from one end of the winding portion 31. The winding portion 31 is threadedly engaged with a guide rail 75 of the holder portion 50 so as to be rotatable in the circumferential direction. The claw portion 32 can abut against a protrusion 83 of a magnet rotor 81 (described later), and rotation of the magnet rotor 81 pushes and rotates the winding portion 31 in the circumferential direction. As a result, the claw portion 32 abuts against an upper limit stopper (FIG. 3) or a lower limit stopper (FIG. 3), restricting rotation of the coil member 30 and the magnet rotor 81. This prevents the valve element 42 from moving beyond the maximum or minimum opening position (or the valve closed state). The coil member 30 can be easily manufactured by forming a metal wire such as stainless steel.

[0026] Here, the upper limit stopper and the lower limit stopper of this embodiment in the support member 70 shown in FIG. 2 will be described in more detail. FIG. 3 is a diagram for explaining the upper limit stopper and the lower limit stopper, and is a perspective view of the holder portion 50 of the support member 70. As shown in FIG. 3, the holder portion 50 has a guide rail 75 consisting of a spiral protrusion integrally formed on its outer peripheral surface 50a. Adjacent winding portions (portions that go around the outer peripheral surface 50a of the holder portion 50) of the guide rail 75 are arranged with a gap between them. The guide rail 75 is threadedly engaged with the winding portion 31 and guides the winding portion 31 from one or both sides so that the coil member 30 can rotate in the circumferential direction. The guide rail 75 is arranged so that its axis overlaps with the axis L. In this embodiment, a portion of the outer peripheral surface 50a of the holder portion 50 is chamfered in the direction of the axis L. As a result, the guide rail 75 is not formed in an actual continuous spiral shape, but in an imaginary continuous spiral shape at the chamfered portion. This facilitates demolding during resin molding of the holder part 50. Of course, this is not limiting, and the holder part 50 may be formed in a cylindrical shape without chamfering as described above, with the guide rail 75 formed in an actual continuous spiral shape.

[0027] A valve-closing lower-limit stopper projection 76 protruding in the radial direction of the guide rail 75 is provided near the end of the guide rail 75 on the outer peripheral surface 50a of the holder part 50 that is closer to the valve port 22, and a piece-shaped valve-open upper-limit stopper projection 77 protruding in the radial direction of the guide rail 75 is provided near the upper end of the outer peripheral surface 50a of the holder part 50 opposite the lower end of the guide rail 75. This valve-open upper-limit stopper projection 77 is located at one end of the holder part 50.

[0028] The valve-closing lower limit stopper projection 76 is provided with a lower limit stopper surface 76a that is formed parallel to the axis L and the radial direction of the guide rail 75 so as to intersect with the guide rail 75 at the lower end of the guide rail 75, so that the claw portions 32 of the coil member 30 abut against the lower limit stopper surface 76a when the coil member 30 is guided by the guide rail 75 and reaches its lower end. The lower limit stopper surface 76a is formed to extend radially outward from the guide rail 75 to the holder portion 50. In other words, the lower limit stopper surface 76a is formed so that its height from the outer circumferential surface 50a of the holder portion 50 is higher than that of the guide rail 75.

[0029] The valve-opening upper limit stopper projection 77 is provided with an upper limit stopper surface 77a that is formed parallel to the axis L and the radial direction of the guide rail 75 so as to intersect with the guide rail 75 at the upper end of the guide rail 75, so that one end of the wound portion 31 of the coil member 30 abuts against the upper limit stopper surface 77a when the coil member 30 is guided by the guide rail 75 and reaches the upper end of the guide rail 75. The upper limit stopper surface 77a is formed to extend radially outward from the guide rail 75 toward the holder portion 50. In other words, the upper limit stopper surface 77a is formed so that its height from the outer peripheral surface 50a of the holder portion 50 is higher than that of the guide rail 75. In the above configuration, the valve-closing lower limit stopper projection 76 and lower limit stopper surface 76a, and the valve-opening upper limit stopper projection 77 and upper limit stopper surface 77a correspond to fixed stoppers, and the coil member 30, which is composed of the wound portion 31 and the claw portions 32, corresponds to a movable stopper.

[0030] However, FIG. 3 described above is an example of a mechanism that functions as a stopper, and the stopper of this embodiment is not limited to the configuration shown in FIG.

[0031] Fig. 4 is a diagram for explaining the stepping motor 80, and is a cross-sectional view of the coil portion 84 of the motor-operated valve 1 shown in Fig. 2. As shown in Fig. 2, the stepping motor 80 includes a magnet rotor 81 and a coil portion 84.

[0032] The coil portion 84 has a cylindrical shape. The coil portion 84 includes a stator 82 and windings 823 and 826. The stator 82 is a unit composed of parts for rotating the magnet rotor 81, and includes an A-phase stator 82A and a B-phase stator 82B (hereinafter, the A-phase stator 82A and the B-phase stator 82B are collectively referred to simply as "stator 82"). The A-phase stator 82A has a plurality of claw-pole-shaped pole teeth 821 and 822 on its inner periphery. The tips of the pole teeth 821 face downward, and the tips of the pole teeth 822 face upward. The pole teeth 821 and the pole teeth 822 are alternately arranged at equal angular intervals in the circumferential direction. In this embodiment, the A-phase stator 82A has ten pole teeth 821 and ten pole teeth 822. The angle between adjacent pole teeth 821 and 822 is 18 degrees. When the winding 823 of the A-phase stator 82A is energized, the pole teeth 821 and 822 become magnetic poles of mutually opposite polarities.

[0033] The B-phase stator 82B has a plurality of claw-pole-shaped pole teeth 824, 825 on its inner circumference. The tips of the pole teeth 824 face downward, and the tips of the pole teeth 825 face upward. The pole teeth 824 and 825 are alternately arranged at equal angular intervals in the circumferential direction. In this embodiment, the B-phase stator 82B has ten pole teeth 824 and ten pole teeth 825. The angle between adjacent pole teeth 824 and 825 is 18 degrees. When a current is applied to the winding 826 of the B-phase stator 82B, the pole teeth 824 and 825 become magnetic poles of mutually opposite polarities.

[0034] The A-phase stator 82A and the B-phase stator 82B are arranged coaxially. The A-phase stator 82A is in contact with the B-phase stator 82B. When viewed from the direction of the axis L, the angle between a pole tooth 821 of the A-phase stator 82A and a pole tooth 824 of the B-phase stator 82B, which are adjacent to each other, is 9 degrees. In other words, the B-phase stator 82B is located at a position rotated 9 degrees around the axis L with respect to the A-phase stator 82B from the position where the pole tooth 821 and the pole tooth 822 are aligned in the direction of the axis L. A terminal of the winding 823 of the A-phase stator 82A and a terminal (not shown) of the winding 826 of the B-phase stator 82B are connected to the motor-operated valve control device 2.

[0035] In this embodiment, the motor load determination process according to the present invention is applied to the initialization process of the motor-operated valve. The initialization process of the motor-operated valve 1 will now be described. The initialization process is performed, for example, when power is applied to an air conditioner, or when the engine is started in the case of an in-vehicle air conditioner. In the initialization process, the valve element 42 first moves to the lower limit position (valve closed) or the upper limit position (valve open), bringing the valve into a fully closed or fully open state. The initialization process is a process for determining the base point of the movable stopper position (adjusting the 0 pulse position). After the valve element 42 reaches the upper limit position or the lower limit position, when further pulses are input to the stepping motor 80, the difference between the phase of the excitation voltage or current of the windings 823, 826 of the stator 82 and the phase of the generated back electromotive force becomes less than 90 degrees. In this embodiment, the difference between the phase of the excitation voltage or current and the phase of the generated back electromotive force is input, and an input signal with a phase difference of less than 90 degrees is set as a specific input signal, and for example, contact of the lower limit stopper surface 76a or the upper limit stopper surface 77a with the coil member 30 is detected.

[0036] After the base point is set, the coil member 30 (winding portion 31, claw portion 32) serving as a movable stopper is rotated a predetermined amount to set the valve element 42 to the desired opening. Specifically, for example, pulses corresponding to operation information indicating the set temperature and timer setting of the air conditioner input to the system control device 58 shown in FIG. 1 are input to the stepping motor 80, and a drive voltage or drive current corresponding to the pulses is supplied to the windings 823, 826, exciting the stator 82 and causing the magnet rotor 81 to rotate. As described above, in this embodiment, either a voltage or a current can be applied to excite the stator 82, but this embodiment will be described taking an example in which a pulse voltage is supplied to the windings 823, 826.

[0037] A pulse voltage is repeatedly input in a predetermined order to the stepping motor 80. When controlling the opening of the valve element 42 in this manner, an initialization process is performed in advance, so that the present embodiment can accurately and stably control the opening of the valve element 42 in accordance with the operation information.

[0038] FIG. 5 is a functional block diagram of the motor-operated valve control device 2 shown in FIG. 1. The motor-operated valve control device 2 controls the motor-operated valve 1, which includes a magnet rotor 81 that opens and closes the valve port 22 and a stepping motor 80 including a coil unit 84 that rotates the magnet rotor 81. The motor-operated valve control device 2 includes a load determination unit 91 that determines the load on the stepping motor 80 based on the phase difference between the excitation voltage supplied to the windings 823 and 826 and the back electromotive force generated in the windings 823 and 826 during the non-energized phase. The load determination unit 91 compares the phase difference with a predetermined threshold and rotates the magnet rotor 81 until the movable stopper (winding unit 31, claw unit 32) abuts against the fixed stopper (valve-closing lower limit stopper projection 76, valve-open upper limit stopper projection 77), and then continues or stops the initialization process. The load determination unit 91 functions as the motor-operated valve control unit of the first embodiment.

[0039] For this reason, the phase of the excitation voltage supplied to windings 823, 826 and the phase of the back electromotive force generated by the excitation are input to load determination unit 91. Load determination unit 91 includes a threshold value storage unit 911, a calculation unit 912, and a signal generation unit 913. The calculation unit 912 calculates the difference (phase difference) between the phase of the excitation voltage and the phase of the back electromotive force. Threshold value storage unit 911 is a memory that stores preset threshold values, and calculation unit 912 compares the calculated phase difference with the threshold value. Based on the result of comparing the phase difference with the threshold value, signal generation unit 913 outputs a signal to issue an alarm to alarm device 93 (described later).

[0040] The motor-operated valve control device 2 of this embodiment further includes a motor driver 92 that supplies an electric pulse signal to the stepping motor 80, and an alarm device 93 that issues an alarm to the operator of the motor-operated valve device 100. When the phase difference is smaller than a threshold value, the motor-operated valve control device 2 outputs a control signal to stop the motor driver 92, for example.

[0041] However, this embodiment is not limited to the configuration shown in Fig. 5. For example, the motor-operated valve control device 2 is not limited to a configuration including the threshold value storage unit 911. In this embodiment, the motor-operated valve control device 2 may be configured to be able to communicate with the outside, and threshold values may be input from the outside depending on the specifications and status of the system. Furthermore, the alarm issued by the alarm device 93 may be an alarm sound, a flashing warning light, a voice message such as "An abnormality has occurred in the system," or even text displayed on a display screen.

[0042] This embodiment is based on the following technical concept. Specifically, the magnitude of the back electromotive force generated when the magnet rotor rotates due to application of an excitation voltage to the coil section varies depending on the excitation voltage. Furthermore, the relationship between the excitation voltage and the back electromotive force can change depending on the state of the device and changes over time. On the other hand, when an excitation voltage is applied, the magnet rotor 81 rotates, and the rotational force of the magnet rotor 81 generates a back electromotive force. At this time, the phase difference between the excitation voltage and the back electromotive force is constant at 90 degrees in a completely no-load state. The inventors focused on this point and set the phase difference between the excitation voltage and the back electromotive force as a threshold for determining the no-load state. Therefore, this embodiment can stably determine the no-load state regardless of the magnitude of the excitation voltage (input signal).

[0043] The first embodiment illustrates the use of the phase difference between the excitation voltage and the back electromotive force to control the initialization process. That is, a known initialization process involves moving the valve element 42 until its movement is restricted by a fixed stopper and a movable stopper. At this time, the stepping motor outputs a control signal to rotate the magnet rotor 81 through the maximum possible angle or more. Regardless of the position of the valve element 42, the magnet rotor 81 rotates at least the maximum possible angle. Therefore, the magnet rotor 81 continues to rotate even after the valve port 22 is fully opened or fully closed, placing a relatively large load on the stepping motor 80.

[0044] In contrast, in the first embodiment, the threshold value is the phase difference between the excitation voltage and the back electromotive force when the valve port 22 is fully closed or fully open. Fig. 6 is a diagram illustrating an example of the threshold value for determining whether the valve port 22 is fully closed or fully open. The horizontal axis of Fig. 6 represents time t, and the vertical axis represents the phase difference (degrees). The phase difference between the excitation voltage and the back electromotive force decreases as the load on the magnet rotor 81, i.e., the stepping motor 80, increases. Fig. 6 shows an example in which the magnet rotor 81 becomes difficult to rotate when the valve port 22 is fully closed or fully open, causing the phase difference to fall below the threshold value Ath and outputting an abnormality signal Sa.

[0045] FIG. 7 is a flowchart for explaining the initialization process of the first embodiment. The initialization process of the first embodiment is started when an instruction for the initialization process is input to the motor-operated valve control device 2, such as when the air conditioner is powered on or the vehicle engine is started. The load determination unit 91 inputs the phase of the excitation voltage and the phase of the back electromotive force, and calculates the phase difference |Δp| therebetween (step S801). Furthermore, the motor-operated valve control device 2 outputs a control signal to the motor driver 92 in response to the instruction for the initialization process. The motor driver 92 includes a stepping motor 80, and inputs a pulse signal to windings 823, 826 of the stepping motor 80 to excite the stator 82 (the above operation will be referred to as "exciting the coil unit 84") (step S802).

[0046] The load determination unit 91 determines whether the phase difference |Δp| is equal to or less than the threshold value Ath (step S803). While the phase difference |Δp| is greater than the threshold value Ath, the motor-operated valve control device 2 continues to excite the coil unit 84 (step S803: NO), and when the phase difference |Δp| becomes smaller than the threshold value Ath (step S803: YES), it determines that the movable stopper has come into contact with the fixed stopper and ends the excitation (step S804). With the above processing, the initialization processing of the first embodiment is completed.

[0047] In the first embodiment described above, the position of the movable stopper is detected with high accuracy using the phase difference |Δp|, and when the movable stopper abuts against the fixed stopper, excitation of the coil portion 84 is terminated. Such a first embodiment can reduce the mechanical load caused by the abutment of the movable stopper and the fixed stopper.

[0048] [Second embodiment] Next, a second embodiment will be described. In the second embodiment, the motor-operated valve control device 2 includes a signal generating unit that generates a signal for instructing the stepping motor 80 about the amount of rotation. The load determining unit 91 functions as the signal generating unit in the second embodiment. The load determining unit 91 generates a signal for executing part initialization, which rotates the stepping motor 80 by a predetermined number of pulses at an amount of rotation that is smaller than the maximum amount of rotation until the movable stopper abuts against the fixed stopper. In the second embodiment, part initialization is executed by rotating the magnet rotor 81 by a number of divided pulses obtained by equally dividing an amount of rotation that exceeds the maximum amount of rotation of the magnet rotor 81 by a predetermined number of divisions.

[0049] FIG. 8 is a diagram for explaining part initialization. FIG. 8 shows position Ps3 of a movable stopper located between position Ps1 of one fixed stopper (e.g., valve-closing lower-limit stopper projection 76) and position Ps2 of the other fixed stopper (e.g., valve-open upper-limit stopper projection 77), and shows the number of input pulses (52, 104, . . . 520) corresponding to each position and the timings t1, t2, . . . t10 at which the pulses are applied. In the second embodiment, 520 pulses are input to windings 823 and 826 during initialization. FIG. 8 shows an example in which 520 pulses are divided into 10 times, from timing t1 to timing t10, and 52 pulses are applied to windings 823 and 826 during one part initialization. In the example shown in FIG. 8, the motor-operated valve 1 is in a state in which the movable stopper abuts against the fixed stopper at the timing when 60 pulses are input. In such a case, while 52 pulses are input at timing t1, the movable stopper does not come into contact with the fixed stopper, and the phase difference |Δp| does not become equal to or less than the threshold value.

[0050] At the next timing t2, the movable stopper abuts against the fixed stopper at the timing when eight pulses are input, and the phase difference |Δp| becomes smaller than the threshold value. Then, at the next timing t3, the phase difference |Δp| becomes equal to or smaller than the threshold value from the start of the part initialization process. In this case, the second embodiment executes the part initialization at timing t3 and ends the initialization process.

[0051] FIG. 9 is a flowchart for explaining the initialization process of the second embodiment. As in the first embodiment, the initialization process of the second embodiment is started when an instruction for the initialization process is input. The load determination unit 91 inputs the phase of the excitation voltage and the phase of the back electromotive force, and calculates the phase difference |Δp| therebetween (step S901). Then, when executing the initialization process, the motor-operated valve control device 2 first counts the number of times part initialization has been executed (step S902). That is, the motor-operated valve control device 2 first sets the number of part initializations n=1, and excites the coil unit 84 (step S903).

[0052] Next, the load determination unit 91 determines whether the phase difference |Δp| is equal to or less than the threshold value Ath (step S904). While the phase difference |Δp| is greater than the threshold value Ath, the motor-operated valve control device 2 continues to excite the coil unit 84 (step S904: NO) and counts the number of times part initialization has been executed (step S902). Furthermore, if the phase difference |Δp| is equal to or less than the threshold value Ath (step S904: YES), it determines whether the count number n has reached the division number, i.e., 10 times in FIG. 8 (step S905).

[0053] In step S905, if the count number n has not reached the division number (step S905: NO), the motor-operated valve control device 2 continues to excite the coil unit 84 (step S907). Furthermore, the load determination unit 91 determines whether the phase difference |Δp| is equal to or less than the threshold value Ath (step S908). If the phase difference |Δp| is not equal to or less than the threshold value Ath (step S908: NO), the number of times part initialization has been executed is counted (step S902).

[0054] If the count number reaches the division number in step S905 (step S905: YES), the motor-operated valve control device 2 terminates excitation of the coil unit 84 (step S906). In this case, the valve port 22 was in a fully closed or fully open state during the initialization process. Furthermore, if the phase difference |Δp| becomes equal to or less than the threshold value Ath in step S908 (step S908: YES), the motor-operated valve control device 2 terminates excitation of the coil unit 84 (step S906). This process, as shown in FIG. 8 , executes part initialization once more after the phase difference Δp becomes equal to or less than the threshold value Ath at timing t2, thereby reliably positioning the valve disc 42 and minimizing the time during which the stepping motor 80 rotates even after the coil member 30 of the movable stopper abuts against the fixed stopper.

[0055] [Third embodiment] Next, a third embodiment will be described. The third embodiment is an example in which the motor-operated valve control device and the motor-operated valve device of the present embodiment are applied to detecting loss of synchronism of a stepping motor 80.

[0056] FIG. 10 is a diagram for explaining the types of step-out detected by the third embodiment. The horizontal axis of FIG. 10 represents time, and the vertical axis represents phase difference. The third embodiment can perform lock determination, light lock determination, and danger level determination. As shown in FIG. 10, the third embodiment sets three thresholds for the differential phase difference: a first threshold Ath, a second threshold Bth, and a third threshold Cth. The relationship between thresholds Ath, Bth, and Cth is threshold Ath<threshold Bth<threshold Cth.

[0057] The lock determination is an example of a determination that a step-out has occurred when the differential phase difference has dropped to the threshold value Ath. The lock determination is an example of a determination that a load similar to that when the movable stopper becomes stuck during the initialization process has been applied to the stepping motor 80. This state can occur, for example, when a foreign object in the fluid gets caught in the sliding portion of the valve, causing it to stop moving completely. This state is also known as a complete lock state, and can also occur when the movable stopper becomes stuck in either the upward or downward direction. When a lock determination is made, the motor-operated valve control device 2 may be configured to output an abnormality signal Sa indicating that a lock determination has been made.

[0058] The light lockup determination is made when the differential phase difference falls between threshold Ath and threshold Bth, which is greater than threshold Ath, and reaches or exceeds threshold Dth, a fourth threshold greater than threshold Bth, within a first period of time Tb. In a motor-operated valve, repeated operation of the valve can gradually increase the resistance of the sliding parts. In such a case, the torque required to rotate the magnet rotor increases. For example, a valve that previously operated at 50% of the rated voltage (or rated current in the case of current drive) may no longer operate at 80% of the rated voltage. In such a state, a change in the state, such as an increase in pressure, or a change in sliding resistance may cause a momentary delay in the rotation of the magnet rotor. The light lockup determination can, for example, identify such an event. The motor-operated valve control device 2 may output an abnormality signal Sb when a light lockup is determined. Furthermore, the abnormality signal Sb may be a unique signal different from the abnormality signal Sa, which indicates a lockup determination.

[0059] The danger level determination is made when the differential phase value falls between the threshold value Bth and the threshold value Cth, which is greater than the threshold value Bth, and continues for a third period of time Tc. The period Tc is set to be sufficiently longer than the period Tb. The danger level refers to a state in which, although there appears to be no abnormality, such as a delay in the rotation of the magnet rotor, the load on the stepping motor is increasing and the rotor torque margin is running out. The danger level determination makes it possible to detect an increase in the load on the stepping motor early and prevent the stepping motor from locking up. When the danger level determination is made, the motor-operated valve control device 2 may output an abnormality signal Sc, which may be a unique signal different from the abnormality signals Sa and Sb.

[0060] FIG. 11 is a flowchart illustrating the process of lock determination according to the third embodiment. The lock determination is performed by periodically detecting the phase difference |Δq| between the phase of the excitation voltage and the phase of the back electromotive force (step S1001). The motor-operated valve control device 2 excites the coil unit 84 (step S1002). Next, the motor-operated valve control device 2 determines whether the phase difference |Δq| is equal to or greater than a threshold value Bth and equal to or less than a threshold value Cth (step S1003). If |Δq| is equal to or greater than the threshold value Bth and equal to or less than a threshold value Cth (step S1003: YES), the motor-operated valve control device 2 determines whether this state continues for a duration of Tc or longer (step S1004). If the duration is equal to or greater than Tc (step S1004: YES), the motor-operated valve control device 2 outputs an abnormality signal Sc (step S1005). If the duration is equal to or less than Tc (step S1004: NO), the motor-operated valve control device 2 determines whether |Δq| is equal to or greater than a threshold value Ath and equal to or less than a threshold value Bth (step S1006).

[0061] In step S1003, if the phase difference |Δq| is not equal to or greater than the threshold Bth and equal to or less than the threshold Cth (step S1003: NO), it is determined whether the phase difference |Δq| is equal to or greater than the threshold Ath and equal to or less than the threshold Bth (step S1006). In step S1006, if the phase difference |Δq| is equal to or greater than the threshold Ath and equal to or less than the threshold Bth (step S1006: YES), it is determined whether the duration is equal to or less than Tb (step S1007). If the duration is equal to or less than Tb (step S1007: YES), the motor-operated valve control device 2 outputs an abnormality signal Sb (step S1008). Furthermore, if the duration is equal to or greater than Tb in step S1007, it is determined whether the phase difference |Δq| is equal to or less than the threshold Ath (step S1009).

[0062] In step S1006, if the phase difference |Δq| is not equal to or greater than the threshold value Ath and not equal to or less than the threshold value Bth (step S1006: NO), it is determined whether the phase difference |Δq| is equal to or less than the threshold value Ath (step S1009). In step S1009, if the phase difference |Δq| is equal to or less than the threshold value Ath (step S1009: YES), the motor-operated valve control device 2 outputs an abnormality signal Sa (step S1010). If the phase difference |Δq| is not equal to or less than the threshold value Ath (step S1009: NO), the motor-operated valve control device 2 calculates the phase difference |Δq| again (step S1001).

[0063] The third embodiment detects the load on the stepping motor with high accuracy using the phase difference between the excitation voltage and the back electromotive force, making it possible to detect the various states described above.Furthermore, since it is possible to detect the possibility of locking before the stepping motor actually locks, it is possible to prevent the system from stopping due to locking.

[0064] [Comparative Example] Next, a comparative example of the present embodiment described above will be described. FIG. 12 is a flowchart illustrating a known initialization process. In the known initialization process, first, the coil unit 84 is excited (step S1101) to rotate the movable stopper to the maximum rotation angle. Then, the motor-operated valve control device determines whether the rotation to the maximum angle (initialization process) has been completed (step S1102). If the initialization is completed (step S1102: YES), the excitation of the coil unit 84 is terminated (step S101). In this comparative example, a rotational force is applied to the rotor regardless of the positional relationship between the movable stopper and the fixed stopper. This generates a resistance between the movable stopper and the fixed stopper, damaging the device and placing an excessive load on the stepping motor. In contrast, the present embodiment quickly detects that the movable stopper has come into contact with the fixed stopper, and terminates initialization, thereby reducing damage to the device and the load on the stepping motor.

[0065] Although the present embodiment has been described above as an example of voltage driving, it can also be applied to current driving, in which case it is sufficient to grasp the phase difference between the driving current and the back electromotive force.

[0066] The motor-operated valve control device according to claim 1 of the present invention comprises a rotor for moving a valve element that opens and closes a valve port, a motor including a coil unit for rotating the rotor, and a motor-operated valve control unit that controls the motor-operated valve that rotates the rotor to open and close the valve port with the valve element, and the motor-operated valve control unit includes a load determination unit that determines the load on the motor based on the phase difference between the excitation voltage or excitation current supplied to the coil unit and the back electromotive force generated in the coil unit during the non-energized phase. With this configuration, this aspect can detect the state of the motor-operated valve using the phase difference between the excitation power and the back electromotive force, which is independent of the excitation power (voltage, current), and therefore can accurately and stably grasp the state of the motor-operated valve.

[0067] In addition, in an electric valve control device according to claim 2 of the present invention, the electric valve comprises a movable stopper member that rotates in conjunction with the rotation of the rotor, and a fixed stopper member that abuts against the movable stopper member when the valve port is fully open or fully closed, and the electric valve control unit compares the phase difference with a predetermined threshold value, and if the phase difference is greater than the reference threshold value, continues the initialization process of rotating the movable stopper member until it abuts against the fixed stopper member, and stops the initialization process if the phase difference becomes smaller than the reference threshold value. With this configuration, this aspect can detect the abutment of the movable stopper member and the fixed stopper member and stop the initialization process, thereby reducing the load on the motor and equipment of the electric valve.

[0068] In addition, in an embodiment of the motor-operated valve control device according to claim 3, the motor-operated valve control unit includes a signal generating unit that generates a signal to instruct the motor about the amount of rotation, and the signal generating unit generates a signal to execute part initialization, which rotates the rotor a predetermined number of pulses by an amount of rotation that is smaller than the maximum amount of rotation until the rotor abuts the movable stopper member. With this configuration, this embodiment can quickly detect the abutment of the movable stopper member and the fixed stopper member by rotating the rotor in small increments, further reducing the load on the motor and the motor of the motor-operated valve.

[0069] In addition, in the motor-operated valve control device according to claim 4, the motor-operated valve control unit executes part initialization by rotating the rotor by a number of divided pulses, which is equal divisions of a rotation amount exceeding the maximum rotation amount by a predetermined number of divisions. This configuration eliminates the need for a new mechanism for stopping initialization during continuous control processing, thereby simplifying rotor rotation control and simplifying the device. Furthermore, in this configuration, if the number of rotations for one initialization is determined based on the allowable time for the movable stopper member and the fixed stopper member to remain in contact with each other, the load on the motor and the motor of the motor-operated valve can be effectively alleviated.

[0070] In addition, in the motor-operated valve control device according to an aspect of claim 5, when the phase difference falls to the first threshold value during execution of part initialization, the motor-operated valve control section executes part initialization at least once if the number of divisions of part initialization has not been reached, and stops part initialization if the number of divisions of part initialization has been reached. With this configuration, this aspect can stop the initialization process after the movable stopper member and the fixed stopper member are reliably brought into contact with each other.

[0071] In addition, in the motor-operated valve control device according to claim 6, the motor-operated valve control unit further includes an alarm generating unit that generates a first alarm signal when the phase difference drops to a first threshold value. With this configuration, this aspect can detect a locked state in which the phase difference drops to the first threshold value, among other out-of-step states of the motor, in a manner that distinguishes it from other states.

[0072] In addition, in the motor-operated valve control device according to an aspect of claim 7, the alarm generating unit generates a second alarm signal when the phase difference falls between the first threshold value and a second threshold value that is larger than the first threshold value and reaches or exceeds a fourth threshold value that is larger than the second threshold value within the first time range. With this configuration, this aspect can detect, among motor out-of-step states, a light lock state in which the phase difference falls to the second threshold value but recovers within a short period of time, in a manner that distinguishes it from other states.

[0073] In addition, in the motor-operated valve control device according to an aspect of claim 8, the alarm generating unit generates a third alarm signal when the phase difference falls between the second threshold value and a third threshold value that is greater than the second threshold value and continues for a second period of time. With this configuration, this aspect can detect, before the motor loses synchronization, a dangerous state in which a load is applied to the motor for a long period of time, even if the motor does not become locked, by distinguishing it from other states.

[0074] Furthermore, an electric valve device according to an aspect of claim 9 includes any one of the above-mentioned electric valve control devices, and an electric valve equipped with a rotor that opens and closes a valve port, and a motor including a coil portion that rotates the rotor. With this configuration, this aspect can provide an electric valve device that uses any one of the above-mentioned electric valve control devices.

[0075] Furthermore, a motor-operated valve control method according to an aspect of claim 10 is a motor-operated valve control method for controlling a motor including a rotor that opens and closes a valve port and a motor including a coil unit that rotates the rotor, and includes the steps of acquiring an excitation voltage or excitation current supplied to the coil unit and a back electromotive force generated in the coil unit during a non-energized phase, calculating a phase difference between the acquired excitation voltage or excitation current and the phase of the back electromotive force, and a load determination unit that determines a load on the motor based on the phase difference.With this method, this aspect can detect the state of the motor-operated valve using the phase difference between the excitation power and the back electromotive force, which is independent of the excitation power (voltage, current), regardless of its specific configuration, and therefore can accurately and stably grasp the state of the motor-operated valve. [Explanation of symbols]

[0076] 1 Electric valve, 2 Electric valve control device, 5 Circulation mechanism, 10 Valve body, 14 Valve chamber 18 first coupling pipe, 22 valve port, 23 valve seat member, 28 second coupling pipe 30 coil member, 31 winding portion, 32 claw portion 40a lower end, 40b upper end, 41 spring holder 42 valve body, 50 holder portion, 50a outer peripheral surface, 50b female thread portion 51 Heat exchanger OUT, 52 Heat exchanger IN 53 four-way valve, 54 compressor, 55 drive shaft, 55a male thread portion, 56 guide portion 56a slide hole, 57 flange portion, 58 system control device, 60 valve body portion 61 valve holder, 63 washer, 70 support member 75 guide rail, 76 valve closing lower limit stopper protrusion, 76a lower limit stopper surface 77 valve opening upper limit stopper protrusion, 77a upper limit stopper surface, 79 fixing portion 80 stepping motor, 81 magnet rotor, 82 stator 83 ridge, 84 coil part, 86 case 91 load determination unit, 92 motor driver 93 Alarm device, 100 Electric valve device, 821, 822, 824, 825 Pole teeth 823, 826 winding, 911 threshold storage unit, 912 calculation unit, 913 signal generation unit

Claims

1. An electric valve control device comprising: a rotor for moving a valve element that opens and closes a valve port; and a motor including a coil unit that rotates the rotor; and an electric valve control unit that controls an electric valve that opens and closes the valve port by rotating the rotor with the valve element, The motor-operated valve control unit a load determination unit that determines a load on the motor based on a phase difference between an excitation voltage or excitation current supplied to the coil unit and a back electromotive force generated in a non-energized phase in the coil unit, Electric valve control device.

2. the motor-operated valve includes a movable stopper member that rotates in conjunction with the rotation of the rotor, and a fixed stopper member that abuts against the movable stopper member when the valve port is fully opened or fully closed; 2. The motor-operated valve control device according to claim 1, wherein the motor-operated valve control unit compares the phase difference with a predetermined threshold value, and when the phase difference is greater than a reference threshold value, continues an initialization process of rotating the movable stopper member until it abuts against the fixed stopper member, and when the phase difference becomes smaller than the threshold value, stops the initialization process.

3. The motor-operated valve control unit a signal generating unit that generates a signal to instruct the motor about a rotation amount; the signal generating unit generates the signal for executing part initialization by rotating the rotor by a predetermined number of pulses at an amount of rotation smaller than the maximum amount of rotation until the rotor abuts against the movable stopper member. The electrically operated valve control device according to claim 2.

4. The motor-operated valve control unit The part initialization is performed by rotating the rotor by a number of divided pulses obtained by equally dividing an amount of rotation exceeding the maximum amount of rotation by a predetermined number of divisions. The electrically operated valve control device according to claim 3.

5. The motor-operated valve control unit 5. The electric valve control device according to claim 4, wherein, when the phase difference decreases to a first threshold value during execution of the part initialization, if the number of divisions of the part initialization has not been reached, the part initialization is executed at least once, and if the number of divisions of the part initialization has been reached, the part initialization is stopped.

6. 2. The motor-operated valve control device according to claim 1, wherein the motor-operated valve control unit further includes an alarm generating unit that generates a first alarm signal when the phase difference decreases to a first threshold value.

7. The warning generation unit 7. The motor-operated valve control device according to claim 6, wherein a second warning signal is generated when the phase difference falls between the first threshold value and a second threshold value that is greater than the first threshold value and reaches or exceeds a fourth threshold value that is greater than the second threshold value within a first time range.

8. The warning generation unit 7. The motor-operated valve control device according to claim 6, wherein a third warning signal is generated when the phase difference falls between the second threshold value and a third threshold value greater than the second threshold value and continues for a second period of time.

9. 9. An electric valve device comprising: the electric valve control device according to claim 1; and an electric valve equipped with a rotor that opens and closes a valve port, and a motor that includes a coil portion that rotates the rotor.

10. A motor-operated valve control method for controlling a motor-operated valve including a rotor that opens and closes a valve port and a motor that includes a coil portion that rotates the rotor, comprising: acquiring an excitation voltage or an excitation current supplied to the coil section and a back electromotive force generated in a non-energized phase in the coil section; calculating a phase difference between the excitation voltage or excitation current and the back electromotive force; a load determination unit that determines a load on the motor based on the phase difference; Motor-operated valve control method.

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