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

Abstract

A motorized valve control device for controlling a motorized valve (20), the motorized valve (20) comprising: a valve body (30) having a valve port (34a); a stepping motor having a rotor (55) and a stator (22) connected to the motor driver; and a valve body (40) that moves relative to the valve port (34a) when the rotor (55) rotates. The electric valve control device supplies a drive current to the stator (22) to rotate the rotor (55), and supplies a post-excitation current having a larger amplitude than the drive current to the stator (22) after the supply of the drive current is completed.

Description

Technical Field

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

[0002] For example, the electric valve disclosed in Patent Document 1 supplies a driving current corresponding to the pulse to the stator by inputting a pulse to the motor driver, causing the rotor to rotate. The rotation of the rotor is transmitted to the drive shaft through a reduction mechanism, and the drive shaft moves axially while rotating, causing the valve core to move axially.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-197849 Summary of the Invention

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

[0007] In the aforementioned electric valve, when the pulse input to the stepper motor stops, the rotor does not stop immediately, potentially causing excessive rotation and loss of stepper motor steps. Therefore, it is considered to suppress excessive rotor rotation by continuously supplying a large drive current corresponding to the pulse to the stator. However, this method presents the problem of wear on components such as gears and drive shafts in the reduction mechanism, leading to reduced durability of the electric valve.

[0008] The purpose of this disclosure is to provide an electric valve control device, an electric valve assembly, and a method for controlling an electric valve that can suppress step loss of a stepper motor and reduce the durability of an electric valve.

[0009] Technical means for solving technical problems

[0010] One aspect of the present invention is an electric valve control device for controlling an electric valve, the electric valve comprising: a valve body having a valve port; a stepper motor having a rotor and a stator connected to a motor driver; and a valve core that moves relative to the valve port when the rotor rotates.

[0011] The electric valve control device supplies a drive current to the stator to make the rotor rotate, and after the drive current supply is completed, it supplies a post-excitation current to the stator with an amplitude larger than that of the drive current.

[0012] Invention Effects

[0013] According to this disclosure, an electric valve control device, an electric valve apparatus, and an electric valve control method can be provided that can suppress stepper motor step loss and reduce the durability of the electric valve. Attached Figure Description

[0014] Figure 1 This is a block diagram of an electric valve device according to an embodiment of the present disclosure.

[0015] Figure 2 This is a longitudinal sectional view of an electric valve according to an embodiment of the present disclosure.

[0016] Figure 3 This is a schematic diagram of the rotor and stator of a stepper motor in an electric valve according to an embodiment of the present disclosure.

[0017] Figure 4 This is a graph showing the current in phase A and phase B of the reference example.

[0018] Figure 5 This is a graph of the A-phase current and the B-phase current according to the first embodiment of this disclosure.

[0019] Figure 6 This is a graph of the A-phase current and the B-phase current according to the second embodiment of this disclosure.

[0020] Figure 7 This is a graph showing the A-phase current and B-phase current according to the third embodiment of this disclosure. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, for configurations that have the same reference numerals as those already described in the embodiments, their descriptions are omitted for ease of explanation. Also, in the following description of the embodiments, the vertical direction is indicated. Figure 2 The direction within the paper is not intended to narrow the scope of the invention.

[0022] <Structure of Electric Valve Device>

[0023] Figure 1 This is a block diagram of an electric valve device 100 according to an embodiment of the present disclosure. The electric valve device 100 includes an electric valve control device 10 and an electric valve 20, for example, controlling the flow rate of refrigerant. The electric valve control device 10 includes a motor driver 11, a processor 12 such as a CPU, and a memory 13. The electric valve 20 includes a stepper motor 21.

[0024] The motor driver 11 is driven by the processor 12 to supply drive current to the stepper motor 21. The processor 12 drives the motor driver 11 with reference to the drive parameters of the stepper motor 21 stored in the memory 13.

[0025] Figure 2 This is a longitudinal sectional view of an electric valve 20 according to an embodiment of the present disclosure. The electric valve 20 includes a stator 22, a valve body 30, a valve core 40, and a drive unit 50. Furthermore, Figure 1 The stepper motor 21 shown is composed of Figure 2The stator 22 and the rotor 55 of the drive unit 50 shown are configured, for example, a PM type stepper motor.

[0026] Stator 22 is composed of phase A stack 23 and phase B stack 24, and is connected via... Figure 1 The motor driver 11 shown supplies drive current to drive the rotor 55 to rotate. Phase A stack 23 and phase B stack 24 are opposite each other in the central axis direction Y, with phase A stack 23 located above phase B stack 24.

[0027] The valve body 30 is a bottomed cylindrical component extending along the central axis Y, and has a main valve chamber 32 inside that houses the valve core 40. The valve body 30 has an inflow passage 33 communicating with the main valve chamber 32 in the left-right direction and an outflow passage 34 extending downward from the main valve chamber 32. The inflow passage 33 is connected to an inflow pipe 35, and the outflow passage 34 is connected to an outflow pipe 36. A main valve seat 37 surrounding the outflow passage 34 is formed at the periphery of the valve port 34a of the outflow passage 34. Alternatively, an electric valve can be used to allow fluid to flow in the opposite direction. In this case, fluid flows into the main valve chamber 32 from the outflow passage 34 side and flows out from the inflow passage 33.

[0028] The valve core 40 has a body 41, a valve portion 42, a spring receiving portion 43, and a ball receiving portion 44. The body 41 has a generally cylindrical shape extending along the central axis direction Y. The valve portion 42 has a generally conical shape with its front end facing downwards and is located below the body 41. The front end of the valve portion 42 is opposite to the valve port 34a of the outlet passage 34 in the central axis direction Y. The spring receiving portion 43 has an annular shape and is located above the body 41. The outer diameter of the spring receiving portion 43 is larger than the outer diameter of the body 41. The body 41, valve portion 42, and spring receiving portion 43 may also be integrally formed. The ball receiving portion 44 is fixed to the upper end of the body 41.

[0029] The valve core 40 is designed to move vertically within the internal space of the valve body 30, and can open or close the outlet passage 34 by sitting on or leaving the main valve seat 37. Therefore, when the valve core 40 is in the open state, the fluid flowing in from the inlet passage 33 flows out through the main valve chamber 32 to the outlet passage 34, and when the valve core 40 is in the closed state, it does not flow out to the outlet passage 34 but stays in the main valve chamber 32.

[0030] Within the internal space of the valve body 30 and between the valve body 30 and the valve core 40, a generally cylindrical sleeve 60 and an opening spring 61 are provided along the central axis direction Y. The sleeve 60 is held on the inner circumferential surface of the valve body 30. The opening spring 61 is radially disposed between the main body portion 60a of the sleeve 60 and the body portion 41 of the valve core 40. Furthermore, the opening spring 61 is vertically disposed between the spring support portion 60b of the sleeve 60 and the spring receiving portion 43 of the valve core 40, applying force to the valve core 40 in a direction away from the valve port 34a. The valve core 40 is supported by the lower portion 60c of the sleeve 60, allowing it to move vertically.

[0031] The drive unit 50 includes a drive shaft 51, a bearing component 52, a connecting component 53, a planetary gear mechanism 54, a rotor 55, and a rotor shaft 56.

[0032] The drive shaft 51 has balls 51a and external threads 51t, and is located inside the valve body 30 and above the valve core 40. The balls 51a engage with the ball receiving portion 44 and are in contact with the lower end face of the drive shaft 51. The external threads 51t are located on the outer circumferential surface of the drive shaft 51. Through the balls 51a, the rotation of the drive shaft 51 is not transmitted to the ball receiving portion 44, but the vertical movement of the drive shaft 51 is transmitted to the ball receiving portion 44.

[0033] The bearing member 52 is generally cylindrical in shape and has an internal thread 52t on its inner circumferential surface. The bearing member 52 is configured to cover the internal space of the valve body 30 and the side of the drive shaft 51. The internal thread 52t protrudes radially inward from the inner circumferential surface of the bearing member 52 and is configured to engage with the external thread 51t.

[0034] The connecting member 53 is a generally circular plate-shaped component, integrally formed with the rotor 55 and the sun gear of the planetary gear mechanism 54. The connecting member 53 is supported by the rotor shaft 56 and transmits the rotation of the rotor 55 to the sun gear of the planetary gear mechanism 54.

[0035] The planetary gear mechanism 54 is a speed reduction mechanism that reduces the rotational speed of the rotor 55 and transmits it to the drive shaft 51. The planetary gear mechanism 54 may consist of, for example, a fixed ring gear, a sun gear, multiple planetary gears, a gear carrier, an output gear, and an output shaft.

[0036] If a drive current is supplied to the stator 22, the rotor 55 rotates. The rotation of the rotor 55 is transmitted to the drive shaft 51 via the planetary gear mechanism 54. If the drive shaft 51 rotates, it moves downward by the action of the feed screw, and the valve core 40 is pressed down. If the valve portion 42 of the valve core 40 is seated on the main valve seat 37, the electric valve 20 closes.

[0037] Figure 3This is a schematic diagram of an electric valve 20 according to an embodiment of the present disclosure, having a rotor 55 of a stepper motor 21 and a stator 22.

[0038] Phase A stack 23 has multiple claw-shaped pole teeth 23a and 23b. The front end of pole tooth 23a faces... Figure 2 Below, the front end of pole tooth 23b faces... Figure 2 Above the center. The pole teeth 23a and 23b are arranged to mesh with each other in a manner offset by 1 / 2 pitch in the circumferential direction. The A-phase stack 23, for example, has 12 pole teeth 23a and 12 pole teeth 23b. Additionally, the A-phase stack 23 has an A-phase coil 23c (not shown). If the A-phase coil 23c is energized, the pole teeth 23a and 23b become magnetic poles with opposite polarities.

[0039] The B-phase stack 24 has multiple claw-shaped pole teeth 24a and 24b, and a B-phase coil 24c (not shown). The front end of the pole tooth 24a faces... Figure 2 Below, the front end of pole tooth 24b faces... Figure 2 Above the center. The pole teeth 24a and 24b are arranged to mesh with each other in a manner offset by 1 / 2 pitch in the circumferential direction. The B-phase stack 24, for example, has 12 pole teeth 24a and 12 pole teeth 24b. Additionally, the B-phase stack 24 has a B-phase coil 24c (not shown). If the B-phase coil 24c is energized, the pole teeth 24a and 24b become magnetic poles with opposite polarities.

[0040] The pole teeth 23a and 23b of phase A stack 23 and the pole teeth 24a and 24b of phase B stack 24 are arranged circumferentially offset by 1 / 4 pitch to form the inner circumferential surface of stator 22. A rotor 55 having multiple rotor magnets 57 is arranged inside the inner circumferential surface of stator 22. The rotor magnets 57 are made of permanent magnets and are approximately the same in size, material, and composition. The magnetic poles of the rotor magnets 57 and the pole teeth 24a and 24b of stator 22 are radially opposite each other. Furthermore, the number of magnetic poles of rotor 55 and the number of pole teeth of stator 22 can be varied according to the application of electric valve device 100.

[0041] <Drive Control of Electric Valve Rotor>

[0042] In this embodiment, the stepper motor 21 is controlled by a 2-2 phase excitation method. In addition, the stepper motor 21 can also be controlled by a 1-phase excitation method, a 1-2 phase excitation method, a W1-2 phase excitation method, a 2W1-2 phase excitation method, or a 4W1-2 phase excitation method, and can also be micro-stepped.

[0043] If the processor 12 inputs a pulse signal P (pulse P[1]~P[4]) to the motor driver 11, then the motor driver 11 supplies a drive current corresponding to pulse P[1]~P[4] to the stepper motor 21, and the rotor 55 rotates. Here, the pulse signal P represents the signal that controls the drive current supplied to the stepper motor 21. In addition, pulse P[1]~P[4] each represent the signal waveform of one step of the pulse signal P. Figure 4 As a reference example, this section shows an example of the waveforms of phase A current and phase B current when the processor 12 periodically inputs pulse signals P to the motor driver 11 in the order of pulses P[1]~P[4] and then inputs the excitation signal.

[0044] like Figure 4 As shown, if the processor 12 inputs pulse P[1] to the motor driver 11, then the motor driver 11 supplies a +I A-phase current to the A-phase coil 23c and a -I B-phase current to the B-phase coil 24c. Additionally, if the processor 12 inputs pulse P[2] to the motor driver 11, then the motor driver 11 supplies a +I A-phase current to the A-phase coil 23c and a +I B-phase current to the B-phase coil 24c. Additionally, if the processor 12 inputs pulse P[3] to the motor driver 11, then the motor driver 11 supplies a -I A-phase current to the A-phase coil 23c and a +I B-phase current to the B-phase coil 24c. Additionally, if the processor 12 inputs pulse P[4] to the motor driver 11, then the motor driver 11 supplies a -I A-phase current to the A-phase coil 23c and a -I B-phase current to the B-phase coil 24c.

[0045] If the processor 12 periodically inputs pulse signals P to the motor driver 11 in the order of pulses P[1] to P[4], then as described above, the rotor 55 moves in the first direction (in Figure 3 (In the clockwise direction) the drive shaft 51 moves downward via the planetary gear mechanism 54, the valve core 40 is pressed down, and the electric valve 20 closes.

[0046] However, even if the processor 12 inputs a pulse signal P to the motor driver 11 and the drive current supply to the stator 22 is completed, the rotor 55 will not stop immediately, and may over-rotate, causing the stepper motor 21 to lose its steps. Therefore, as Figure 4 As shown, after the drive current interval ends, the processor 12 inputs a post-excitation signal to the motor driver 11 in the post-excitation current interval. The electric valve control device 10 supplies +I A-phase current to the A-phase coil 23c as the post-excitation current and -I B-phase current to the B-phase coil 24c as the post-excitation current. This stops the rotor 55 and prevents it from losing synchronization.

[0047] Here, the inventors conducted the following research: In order to stop the stepper motor 21 more quickly and prevent step loss more effectively, after the drive current is supplied, a post-excitation current with a larger amplitude than the drive current is supplied to the stator 22.

[0048] Figure 5 This is a graph showing the A-phase current and B-phase current according to the first embodiment of this disclosure. (See figure) Figure 5 As shown, after the drive current supply to the stator 22 is completed, i.e., after the drive current interval ends, the electric valve control device 10 supplies A-phase current and B-phase current, respectively, with an amplitude of +I' greater than the drive current |I|, to the A-phase coil 23c and B-phase coil 24c during the post-excitation current interval. This prevents the stepper motor 21 from losing steps more effectively after the drive current supply is completed without reducing the durability of the electric valve 20. Alternatively, immediately after the drive current supply to the stator 22 is completed, A-phase current and B-phase current, respectively, with an amplitude of +I' greater than the drive current |I|, can be supplied to the A-phase coil 23c and B-phase coil 24c as post-excitation current.

[0049] Figure 6 This is a graph showing the A-phase current and B-phase current according to the second embodiment of this disclosure. (See figure) Figure 6 As shown, the electric valve control device 10 can also, during the after-excitation current range, from the completion of the supply of the drive current to the stator 22 until a predetermined time T1, supply the A-phase current and B-phase current, respectively, with an amplitude of +I equal to that of the drive current, to the A-phase coil 23c and B-phase coil 24c. After the predetermined time T1, it supplies the A-phase current and B-phase current, respectively, with an amplitude of +I' greater than that of the drive current, to the A-phase coil 23c and B-phase coil 24c, respectively, as the after-excitation current. Furthermore, the electric valve control device 10 can either continuously supply the A-phase current and B-phase current, respectively, to the A-phase coil 23c and B-phase coil 24c for a predetermined period Td, or it can continuously supply them beyond the predetermined period Td. Moreover, the predetermined period Td is a longer time than the time until the rotor 55 completely stops (the rotational amplitude substantially disappears); for example, it is 100 times the period of the pulse P.

[0050] Figure 7 This is a graph showing the A-phase current and B-phase current according to the third embodiment of this disclosure. (See figure) Figure 7As shown, the electric valve control device 10 can also, within the after-excitation current range, from the completion of the supply of the drive current to the stator 22 until a predetermined time T2, supply the A-phase current and B-phase current, respectively, with an amplitude of +I equal to the drive current |I|, to the A-phase coil 23c and B-phase coil 24c, respectively, as the after-excitation current. After the predetermined time T2, the magnitude of the after-excitation current is gradually increased to +I', which is larger than the amplitude of the drive current |I|. Alternatively, the electric valve control device 10 can also, after a predetermined time T3 from the start of the after-excitation current supply, gradually decrease the magnitude of the after-excitation current from +I' to +I, or gradually decrease it to 0. Furthermore, T3-T2, the difference between the predetermined time T2 and the predetermined time T3, is a longer time than the time until the rotor completely stops (the rotational amplitude substantially disappears); for example, it is 100 times the period of pulse P.

[0051] In addition, Figure 5 Alternatively, the magnitude of the post-excitation current can be gradually increased to +I' immediately after the drive current supply to stator 22 is completed. Furthermore, in Figure 6 In this context, the specified time T1 can also be 0. Additionally, in... Figure 7 In this context, the specified time T2 can also be 0. Furthermore, in... Figure 6 , Figure 7 In this case, the magnitude of the post-excitation current can be gradually increased from +I to +I' and then rapidly decreased from +I' back to +I, or it can be rapidly increased from +I to +I' and then gradually decreased from +I' back to +I.

[0052] In this way, by supplying a post-excitation current to the stator with a larger amplitude than the drive current after the drive current to the stator 22 is supplied, the stepper motor 21 can be prevented from losing steps after the drive current is supplied without reducing the durability of the electric valve 20.

[0053] The above describes the embodiments of this disclosure. However, the technical scope of this disclosure should not be interpreted as limiting. Those skilled in the art will understand that this embodiment is merely an example, and various modifications to the embodiments can be made within the scope of the technical solutions described in the protection scope. The technical scope of this disclosure should be determined based on the scope of the technical solutions described in the protection scope and their equivalents.

[0054] For example, in embodiments of this disclosure, the electric valve 20 may also be a direct-acting electric valve that directly transmits the rotation of the rotor 55 to the drive shaft 51.

[0055] Furthermore, in the embodiments of this disclosure, the electric valve control device 10 can also calculate the angular velocity ω of the rotor 55. If it determines that the angular velocity ω of the rotor 55 has reached a preset peak value Cp when the drive current supply is completed, it makes the amplitude of the after-excitation current larger than that of the drive current in the after-excitation current range. When the angular velocity ω reaches its peak value Cp when the drive current supply is completed, the stepper motor 21 is more likely to lose steps. Therefore, as described above, by controlling the magnitude of the after-excitation current according to the angular velocity ω of the rotor 55, it is possible to more effectively prevent the stepper motor 21 from losing steps after the drive current supply is completed.

[0056] Furthermore, the angular velocity ω can be calculated using the back electromotive force e generated in rotor 55 via the following equation 1. Here, Ke represents the back electromotive force constant. The back electromotive force constant Ke is determined by the capacitance of phase A coil 23c, phase B coil 24c, etc.

[0057] (Equation 1)

[0058] The relationship between the angular velocity ω up to its peak value Cp and the back electromotive force e generated in the rotor 55 is determined in advance, as is the relationship between the number of pulse signals P input by the processor 12 to the motor driver 11 and the back electromotive force e generated in the rotor 55. Table data representing these relationships and the peak value Cp are stored as driving parameters in the memory 13, and the processor 12 can refer to these driving parameters from the memory 13. Alternatively, the back electromotive force constant Ke from Equation 1 above can be stored as a driving parameter in the memory 13 instead of the table data representing the relationship between the angular velocity ω and the back electromotive force e generated in the rotor 55.

[0059] The processor 12 refers to a table stored in memory 13 showing the relationship between the number of input pulse signals P and the back electromotive force (EMF) e, and calculates the back EMF e generated in the rotor 55 based on the number of input pulse signals P. Next, referring to a table stored in memory 13 showing the relationship between angular velocity ω and back EMF e, or the back EMF constant Ke, the processor calculates the angular velocity ω based on the back EMF e. It determines whether the angular velocity ω calculated when the drive current supply is completed has reached its peak value Cp. If the angular velocity ω reaches its peak value Cp when the drive current supply is completed, the amplitude of the after-excitation current is made larger than that of the drive current in the after-excitation current range; if the angular velocity ω has not reached its peak value Cp, the amplitude of the after-excitation current is not made larger than that of the drive current in the after-excitation current range.

[0060] Furthermore, instead of processor 12 calculating the back electromotive force e generated in rotor 55 based on the number of pulse signals P input, the back electromotive force e can be measured in real time by the voltage acquisition unit (not shown) of electric valve control device 10. This allows for the calculation of a more accurate angular velocity ω.

[0061] This application is based on Japanese Patent Application No. 2024-092914, filed on June 7, 2024, the contents of which are incorporated herein by reference.

[0062] Explanation of reference numerals in the attached figures

[0063] 10: Electric valve control device

[0064] 11: Motor driver

[0065] 12: Processor

[0066] 13: Memory

[0067] 20: Electric valve

[0068] 21: Stepper motor

[0069] 22: Stator

[0070] 23: A-phase stack

[0071] 23a, 23b: Polar teeth

[0072] 24: B-phase pile

[0073] 24a, 24b: Polar teeth

[0074] 30: Valve body

[0075] 32: Main valve chamber

[0076] 33: Inflow route

[0077] 34: Outflow route

[0078] 35: Inflow pipe

[0079] 36: Outflow tube

[0080] 37: Main valve seat

[0081] 40: Valve core

[0082] 41: Torso

[0083] 42: Valve part

[0084] 43: Spring bearing part

[0085] 44: Ball bearing assembly

[0086] 50: Drive Unit

[0087] 51: Drive shaft

[0088] 51a: Ball bearing

[0089] 51t: External thread

[0090] 52: Bearing components

[0091] 52t: Internal thread

[0092] 53: Connecting components

[0093] 54: Planetary gear mechanism

[0094] 55: Rotor

[0095] 56: Rotor shaft

[0096] 57: Rotor magnet

[0097] 60: Sleeve

[0098] 60a: Main part

[0099] 60b: Spring receiving part

[0100] 60c: Lower part

[0101] 61: Valve opening spring

Claims

1. An electric valve control device that controls an electric valve having a valve body having a valve port, a stepping motor having a rotor and a stator connected to a motor driver, and a valve element that moves with respect to the valve port when the rotor rotates, characterized by supplying a drive current to the stator to rotate the rotor, and supplying a post-excitation current larger in amplitude than the drive current to the stator after the supply of the drive current is completed.

2. The electric valve control device according to claim 1, characterized in that the electric valve control device supplies the post-excitation current larger in amplitude than the drive current to the stator when it is determined that the angular velocity of the rotor reaches a peak at the completion of the supply of the drive current.

3. The electric valve control device according to claim 1, characterized in that the electric valve control device supplies the post-excitation current larger in amplitude than the drive current to the stator immediately after the completion of the supply of the drive current.

4. The electric valve control device according to claim 1, characterized in that the electric valve control device supplies the post-excitation current larger in amplitude than the drive current to the stator after a first prescribed time elapses from the completion of the supply of the drive current.

5. The electric valve control device according to claim 1, characterized in that the electric valve control device supplies the post-excitation current larger in amplitude than the drive current to the stator for a prescribed period.

6. The electric valve control device according to claim 1, characterized in that the electric valve control device gradually increases the magnitude of the post-excitation current from the start of the supply of the post-excitation current to the stator.

7. The electric valve control device according to claim 1, characterized in that the electric valve control device gradually decreases the magnitude of the post-excitation current after a second prescribed time elapses from the start of the supply of the post-excitation current to the stator.

8. The electric valve control device according to claim 1, characterized in that the electric valve control device decreases the magnitude of the post-excitation current to the amplitude of the drive current after a third prescribed time elapses from the start of the supply of the post-excitation current to the stator.

9. An electric valve device having the electric valve and the electric valve control device according to any one of claims 1 to 8.

10. A control method of an electric valve having a valve body having a valve port, a stepping motor having a rotor and a stator connected to a motor driver, and a valve element that moves with respect to the valve port when the rotor rotates, characterized by supplying a drive current composed of pulses to the stator to rotate the rotor, and supplying a post-excitation current larger in amplitude than the drive current to the stator after the supply of the drive current is completed. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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