Pump device and program for pump device

Abstract

A pump device includes a first pump and a second pump. The pump device also includes a driver and a controller. The first pump and the second pump are connected in parallel with each other on an electric power supply path from the driver. The controller is capable of acquiring an impedance value of the first pump and an impedance value of the second pump, and identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump. The controller is capable of controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value.

Description

CROSS REFERENCE TO RELATED APPLICATION

[0001] This is a continuation of International Application No. PCT / JP 2024 / 040556 filed on Nov. 15, 2024 which claims priority from Japanese Patent Application No. 2023-208568 filed on Dec. 11, 2023. The contents of these applications are incorporated herein by reference in their entireties.BACKGROUND OF THE DISCLOSUREField of the Disclosure

[0002] The present disclosure relates to a pump device and a program for the pump device.Description of the Related Art

[0003] A pump device disclosed in Japanese Patent No. 7219722 includes a driver, a first pump, a second pump, and a controller. The driver performs voltage conversion on electric power supplied from a power supply and supplies the electric power to the first pump and the second pump. The first pump and the second pump are piezoelectric pumps and are capable of pumping a gas. The first pump and the second pump are connected in parallel with each other on an electric power supply path from the driver. That is, substantially the same drive voltage is applied to the first pump and the second pump. The controller controls a drive voltage to be supplied from the driver to each pump.BRIEF SUMMARY OF THE DISCLOSURE

[0004] In a pump device such as that disclosed in Japanese Patent No. 7219722, the variation characteristics of the impedance value of each pump with respect to the environmental temperature differ from one individual to another. Thus, for example, when a drive voltage is controlled based on the impedance value of one pump, a current larger than assumed may flow through the other pump depending on the environmental temperature.

[0005] To solve the above problem, the present disclosure provides a pump device including: a first pump that is an electric pump capable of pumping a fluid; a second pump that is an electric pump capable of pumping a fluid; a driver capable of converting an input voltage and supplying electric power to the first pump and the second pump; and a controller configured to control the driver, wherein the first pump and the second pump are connected in parallel with each other on an electric power supply path from the driver, and the controller is capable of executing: an identification process for identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump; and a driving process for controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

[0006] The present disclosure also provides a program for a pump device, the pump device including a first pump that is an electric pump capable of pumping a fluid, a second pump that is an electric pump capable of pumping a fluid, a driver capable of converting an input voltage and supplying electric power to the first pump and the second pump, and a controller configured to control the driver, the first pump and the second pump being connected in parallel with each other on an electric power supply path from the driver, the program enabling the controller to execute an identification process for identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump, and a driving process for controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

[0007] It is possible to suppress an unexpectedly large current from flowing through a pump.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0008] FIG. 1 is a perspective view of a nebulizer.

[0009] FIG. 2 is a schematic configuration diagram of a pump device according to a first embodiment.

[0010] FIG. 3 is a flowchart of switching control.

[0011] FIG. 4 is a schematic configuration diagram of a pump device according to a second embodiment.

[0012] FIG. 5 is a flowchart of feedback control.DETAILED DESCRIPTION OF THE DISCLOSURE

[0013] A first embodiment and a second embodiment of a pump device and a program for the pump device will be described hereinafter. In each embodiment, the pump device is applied to a nebulizer. The drawings may illustrate components on an enlarged scale to facilitate understanding. Dimensional ratios of the components may differ from actual ones or from those in other drawings.First Embodiment of Pump Device and Program for Pump Device(Overall Configuration of Nebulizer)

[0014] As illustrated in FIG. 1, a nebulizer 10 includes a pump device 20, a tank unit 30, and a discharge unit 40.

[0015] The pump device 20 includes a housing 21, a first pump P1, and a second pump P2. The housing 21 has a substantially cylindrical appearance. Further, the housing 21 has a hollow portion therein. In the following description, an axis parallel to a central axis of the housing 21 is defined as a reference axis AX. One direction parallel to the reference axis AX is defined as an upward direction UD, and a direction opposite to the upward direction UD is defined as a downward direction DD.

[0016] The first pump P1 is an electric pump. The first pump P1 is located in the housing 21. Specifically, the first pump P1 is a micro blower using a piezoelectric element. This micro blower may also be referred to as a piezoelectric pump, an air pump, or the like. Although not illustrated, the first pump P1 has a diaphragm, a piezoelectric element, an inlet, and an outlet. The diaphragm is a thin film having elasticity. The piezoelectric element is attached to the diaphragm. The piezoelectric element is ceramic. When a voltage is applied to the piezoelectric element, the piezoelectric element undergoes flexural vibration. The diaphragm repeatedly undergoes bending deformation in conjunction with the flexural vibration of the piezoelectric element, thereby causing a gas sucked from the inlet to be pumped from the outlet. Thus, the first pump P1 is capable of pumping a gas. The first pump P1 is also capable of atomizing a liquid by spraying the pumped gas onto the liquid.

[0017] Within the housing 21, the outlet of the first pump P1 faces in the upward direction UD. The outlet of the first pump P1 communicates with the outside of the pump device 20 through an upward-direction-UD-side end face of the pump device 20. Thus, the gas discharged through the outlet of the first pump P1 is discharged in the upward direction UD of the housing 21. The inlet of the first pump P1 faces in the downward direction DD.

[0018] The second pump P2 is an electric pump. The second pump P2 is located in the housing 21. The second pump P2 is a pump complying with the same specifications as the first pump P1. That is, the second pump P2 is a micro blower using a piezoelectric element. Thus, the second pump P2 is capable of pumping a gas.

[0019] Within the housing 21, an outlet of the second pump P2 faces in the upward direction UD. The outlet of the second pump P2 is connected to the inlet of the first pump P1. That is, the first pump P1 and the second pump P2 are connected in series on a gas flow path. Thus, the gas pumped from the outlet of the second pump P2 is sucked into the first pump P1. The gas sucked into the first pump P1 is increased in pressure and flow rate and pumped by the first pump P1.

[0020] The variation characteristics of the impedance value of each pump with respect to the environmental temperature differ from one individual pump to another. This is attributable to manufacturing errors of each pump, temporal changes after manufacture, and the like. That is, even at the same environmental temperature, the impedance value of the first pump P1 and the impedance value of the second pump P2 may have a magnitude relationship. Furthermore, as the environmental temperature changes, the magnitude relationship between the impedance value of the first pump P1 and the impedance value of the second pump P2 may be reversed. The environmental temperature refers to the ambient temperature of each pump. The impedance value refers to the absolute value of impedance.

[0021] As illustrated in FIG. 1, the tank unit 30 is attached to the upward direction UD side of the pump device 20. The tank unit 30 includes a tank body 31 and an atomizing nozzle (not illustrated).

[0022] The tank body 31 is substantially cylindrical and has a bottom surface. That is, one end face of the tank body 31 is open. In a state in which the tank unit 30 is attached to the pump device 20, the opening of the tank body 31 faces in the upward direction UD. Thus, the tank body 31 can store a liquid medicine or the like.

[0023] The atomizing nozzle (not illustrated) is attached to the bottom surface of the tank body 31 within the tank body 31. The atomizing nozzle has an air blowing nozzle and a water suction nozzle, which are not illustrated. The air blowing nozzle is a through hole extending along the reference axis AX. The air blowing nozzle is connected to the outlet of the first pump P1. Thus, the gas pumped by the first pump P1 is discharged through the air blowing nozzle of the atomizing nozzle. The water suction nozzle supplies a liquid stored at the bottom of the tank body 31 to the vicinity of an open end of the air blowing nozzle. Thus, the liquid that has reached the vicinity of the air blowing nozzle through the water suction nozzle is sprayed with the gas pumped by the first pump P1 and the second pump P2 of the pump device 20 and becomes mist.

[0024] As illustrated in FIG. 1, the discharge unit 40 is attached to the upward direction UD side of the tank unit 30. The discharge unit 40 includes a case 41, an intake hole 42, and a discharge nozzle 43. The case 41 is substantially cylindrical, with one end face being open and the other end face being closed. The opening of the case 41 is fitted into the opening of the tank body 31. Thus, an internal space is defined by the tank body 31 and the case 41.

[0025] The intake hole 42 is a through hole that penetrates a surface of the case 41 that faces in the upward direction UD. That is, the intake hole 42 allows the internal space of the case 41 to communicate with the external space thereof.

[0026] The discharge nozzle 43 is a tube protruding from a side surface of the case 41. The discharge nozzle 43 is located in the vicinity of an upward-direction-UD-side end of the side surface of the case 41. One end of the discharge nozzle 43 is connected to the internal space of the case 41. Thus, the liquid atomized by the pump device 20 and the tank unit 30 is discharged from the discharge nozzle 43 through the internal space defined by the case 41 and the tank body 31.(Electrical Configuration of Pump Device according to First Embodiment)

[0027] As illustrated in FIG. 2, the pump device 20 of the nebulizer 10 includes a driver 50 and a controller 70. The driver 50 and the controller 70 are housed in the housing 21 of the pump device 20.

[0028] The driver 50 includes a power conversion circuit 51, a first drive circuit D1, and a second drive circuit D2. The driver 50 is capable of converting a voltage from an external power supply device PU and supplying electric power to the first pump P1 and the second pump P2. The power supply device PU may be a secondary battery housed in the housing 21 of the pump device 20.

[0029] The power conversion circuit 51 is connected to the power supply device PU. The power conversion circuit 51 converts a DC voltage inputted from the power supply device PU and outputs a drive voltage Vp. Specifically, the power conversion circuit 51 is a step-up converter. The power conversion circuit 51 has a plurality of switching elements (not illustrated). The plurality of switching elements are, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The power conversion circuit 51 converts the DC voltage inputted from the power supply device PU into a voltage having a predetermined voltage value by switching on and off the plurality of switching elements. The power conversion circuit 51 outputs the converted voltage as the drive voltage Vp.

[0030] The first drive circuit D1 is connected between the power conversion circuit 51 and the first pump P1. Specifically, the first drive circuit D1 includes an H-bridge circuit (not illustrated). The H-bridge circuit includes an input terminal and a pair of output terminals. The input terminal of the H-bridge circuit is connected to the power conversion circuit 51. The pair of output terminals of the H-bridge circuit is connected to the first pump P1. The pair of output terminals output voltages having the same absolute value and opposite phases at a predetermined drive frequency. Thus, the first drive circuit D1 converts the DC voltage supplied from the power conversion circuit 51 into AC power and supplies the AC power to the first pump P1.

[0031] When electric power is supplied from the first drive circuit D1 to the first pump P1, the piezoelectric element of the first pump P1 is excited. That is, the first pump P1 is driven. In the present embodiment, the first drive circuit D1 is a self-excited oscillation circuit. That is, the first drive circuit D1 controls, within the first drive circuit D1, the drive frequency of the AC voltage to be applied to the first pump P1, independently of external control.

[0032] The second drive circuit D2 is connected between the power conversion circuit 51 and the second pump P2. Specifically, the second drive circuit D2 includes an H-bridge circuit (not illustrated). The H-bridge circuit includes an input terminal and a pair of output terminals. The input terminal of the H-bridge circuit is connected to the power conversion circuit 51. The pair of output terminals of the H-bridge circuit is connected to the second pump P2. Thus, the second drive circuit D2 converts the DC voltage supplied from the power conversion circuit 51 into AC power and supplies the AC power to the second pump P2.

[0033] When electric power is supplied from the second drive circuit D2 to the second pump P2, the piezoelectric element of the second pump P2 is excited. That is, the second pump P2 is driven. In the present embodiment, the second drive circuit D2 is a self-excited oscillation circuit.

[0034] As described above, the first pump P1 and the second pump P2 are connected to the same power conversion circuit 51 via the corresponding drive circuits. That is, the first pump P1 and the second pump P2 are connected in parallel with each other on an electric power supply path from the driver 50. More specifically, substantially the same drive voltage Vp is applied to the first pump P1 and the second pump P2 from the driver 50.

[0035] The controller 70 is housed in the housing 21 of the pump device 20. The controller 70 controls the driver 50. Specifically, the controller 70 has an arithmetic processing unit 71 and a storage unit 72.

[0036] The storage unit 72 of the controller 70 stores a predetermined program PG in advance. The arithmetic processing unit 71 of the controller 70 is capable of executing the program PG. That is, the controller 70 is an MCU (Microcontroller Unit). The arithmetic processing unit 71 of the controller 70 executes the program PG to control the power conversion circuit 51 of the driver 50. Specifically, the arithmetic processing unit 71 inputs a PWM (Pulse Width Modulation) signal to gate terminals of the plurality of switching elements of the power conversion circuit 51. Accordingly, the on / off states of the respective switching elements are switched. Consequently, the magnitude of the drive voltage Vp to be outputted by the power conversion circuit 51 is controlled.(Switching Control According to First Embodiment)

[0037] When electric power is supplied from the power supply device PU to the pump device 20, the power conversion circuit 51 of the driver 50 applies the drive voltage Vp to the first pump P1 and the second pump P2 through the first drive circuit D1 and the second drive circuit D2, respectively. Thereafter, the arithmetic processing unit 71 of the controller 70 executes the program PG stored in the storage unit 72 to start switching control. The switching control is a control method for controlling the driver 50 such that an identification process S11 is performed to identify, as a specific pump, a pump having a minimum impedance value from among the first pump P1 and the second pump P2 and such that a drive current to be supplied to the first pump P1 and the second pump P2 has a value less than or equal to a prescribed current value determined in advance for the specific pump. The arithmetic processing unit 71 of the controller 70 repeatedly executes the switching control at intervals of a predetermined time.

[0038] Immediately before starting the switching control, the arithmetic processing unit 71 controls the power conversion circuit 51 of the driver 50, with one of the first pump P1 and the second pump P2 being designated as a pump to be controlled. The pump to be controlled is the specific pump identified by the identification process S11 described below in the preceding switching control. In the switching control performed when electric power is first supplied to the pump device 20 after manufacture of the pump device 20, the arithmetic processing unit 71 controls the power conversion circuit 51, with a pump determined in advance from among the first pump P1 and the second pump P2 being designated as a pump to be controlled. The pump to be controlled is controlled in accordance with a driving process S14 described below.

[0039] As illustrated in FIG. 3, when the switching control is started, the arithmetic processing unit 71 of the controller 70 executes an acquisition process S10. In the acquisition process S10, the controller 70 acquires the impedance value of the first pump P1 and the impedance value of the second pump P2.

[0040] Specifically, as illustrated in FIG. 2, the arithmetic processing unit 71 acquires the drive voltage Vp outputted by the power conversion circuit 51. The arithmetic processing unit 71 further acquires a first drive current Ip1 inputted from the first drive circuit D1 to the first pump P1 and a second drive current Ip2 inputted from the second drive circuit D2 to the second pump P2. Subsequently, the arithmetic processing unit 71 divides the drive voltage Vp by the first drive current Ip1 to calculate the impedance value of the first pump P1. The arithmetic processing unit 71 divides the drive voltage Vp by the second drive current Ip2 to calculate the impedance value of the second pump P2.

[0041] As described above, the variation characteristics of the impedance value of each pump with respect to the environmental temperature differ from one individual pump to another. Thus, when the environmental temperature changes, the magnitude relationship between the impedance value of the first pump P1 and the impedance value of the second pump P2 may be reversed. That is, at the start of driving of the first pump P1 and the second pump P2, the impedance value of the first pump P1 may be greater than the impedance value of the second pump P2, and after a predetermined time elapses from the start of driving, the impedance value of the first pump P1 may become smaller than the impedance value of the second pump P2. Alternatively, at the start of driving, the impedance value of the second pump P2 may be greater than the impedance value of the first pump P1, and after a predetermined time elapses from the start of driving, the impedance value of the second pump P2 may become smaller than the impedance value of the first pump P1.

[0042] As illustrated in FIG. 3, after the acquisition process S10, the arithmetic processing unit 71 performs the identification process S11. In the identification process S11, a pump having a minimum impedance value from among the first pump P1 and the second pump P2 is identified as the specific pump. Specifically, the impedance value of the first pump P1 and the impedance value of the second pump P2, which are acquired in the acquisition process S10, are compared, and a pump having a smaller impedance value is identified as the specific pump.

[0043] After the identification process S11, the arithmetic processing unit 71 performs a comparison process S12. In the comparison process S12, the arithmetic processing unit 71 determines whether the pump designated as a pump to be controlled at the time when the comparison process S12 is started is the same as the specific pump identified in the identification process S11. In other words, the arithmetic processing unit 71 determines whether the magnitude relationship between the impedance values of the respective pumps is reversed between the time when the preceding switching control is executed and the time when the current switching control is executed.

[0044] If the pump to be controlled and the specific pump are different in the comparison process S12 (S12: YES), the arithmetic processing unit 71 performs a switching process S13. In other words, if the magnitude relationship between the impedance values is reversed between the time when the preceding switching control is executed and the time when the current switching control is executed, the arithmetic processing unit 71 performs the switching process S13. In the switching process S13, the pump to be controlled is switched to the specific pump.

[0045] Specifically, information indicating that the first pump P1 or the second pump P2 identified in the most recent identification process S11 is the pump to be controlled is stored in the storage unit 72. For example, it is assumed that the pump to be controlled at the time when the comparison process S12 is started is the first pump P1 and that the specific pump identified in the identification process S11 is the second pump P2. In this case, the arithmetic processing unit 71 rewrites the information of the pump stored as the specific pump in the storage unit 72 from the first pump P1 to the second pump P2.

[0046] On the other hand, if the pump to be controlled and the specific pump are the same in the comparison process S12 (S12: NO), the arithmetic processing unit 71 maintains the information stored as the specific pump in the storage unit 72 without change.

[0047] After a negative determination is made in the comparison process S12 or after the switching process S13 is performed, the controller 70 performs a driving process S14. In the driving process S14, the arithmetic processing unit 71 controls the drive voltage Vp, based on the impedance value of the specific pump to be controlled. Specifically, the arithmetic processing unit 71 controls the power conversion circuit 51 of the driver 50 such that both the first drive current Ip1 to be supplied to the first pump P1 and the second drive current Ip2 to be supplied to the second pump P2 have values less than or equal to a prescribed current value determined in advance for the specific pump. In the present embodiment, the term “prescribed current value” refers to the value of the rated current of the pump to be controlled. The term “value less than or equal to the prescribed current value” refers to the rated current.

[0048] With the above switching control, the arithmetic processing unit 71 of the controller 70 controls the driver 50 such that the first drive current Ip1 to be supplied to the first pump P1 and the second drive current Ip2 to be supplied to the second pump P2 have values less than or equal to the prescribed current value determined in advance for the specific pump. The series of switching control is repeatedly executed during driving of the pump device 20. Thus, the drive current flowing through the specific pump is maintained at or less than the prescribed current value.(Operation of First Embodiment)

[0049] As described above, the variation characteristics of the impedance values of pumps with respect to the environmental temperature vary from one individual pump to another. Thus, as the environmental temperature changes, the magnitude relationship between the impedance values of the respective pumps may be reversed.

[0050] For example, it is assumed here that the arithmetic processing unit 71 controls the driver 50 with only the first pump P1 being designated as a pump to be controlled, such that the first drive current Ip1 is equal to the rated current. In this case, when the impedance value of the second pump P2 is smaller than the impedance value of the first pump P1, a current larger than the rated current assumed as the current flowing through the second pump P2 may flow.

[0051] According to the above-described embodiment, in the identification process S11, the arithmetic processing unit 71 of the controller 70 identifies a specific pump having a minimum impedance value. In the switching process S13, the arithmetic processing unit 71 stores the specific pump as a control target. Subsequently, in the driving process S14, the arithmetic processing unit 71 controls the driver 50 such that the respective drive currents to be supplied to the first pump P1 and the second pump P2 are equal to the rated current. That is, the specific pump having the minimum impedance value at the time when the switching control is executed is designated as the control target.(Effects of First Embodiment)(1-1) In the first embodiment, the controller 70 controls the drive voltage Vp, with the specific pump having the minimum impedance designated as the control target. That is, the controller 70 designates, as the control target, the specific pump through which current flows most easily. Accordingly, it is possible to suppress an unexpectedly large current from flowing through the pumps connected in parallel with each other, even if the magnitude relationship between the impedances of the respective pumps is reversed due to a change in environmental temperature or the like.

[0053] (1-2) In the first embodiment, the magnitude relationship between the impedance value of the first pump P1 and the impedance value of the second pump P2 is reversed. The pumps having such impedance characteristics are suitable for a configuration that performs switching control.

[0054] (1-3) In the first embodiment, the controller 70 identifies a specific pump, based on the impedance values acquired in the acquisition process S10. Since the impedance values of the respective pumps are directly calculated, it is possible to enhance the accuracy of determination in the comparison process S12 as to whether the magnitude relationship between the impedance values of the respective pumps is reversed.Second Embodiment of Pump Device and Program for Pump Device

[0055] The second embodiment of the pump device and the program for the pump device will be described hereinafter. The overall configuration of the nebulizer 10 according to the second embodiment is the same as the overall configuration of the nebulizer 10 according to the first embodiment, and thus the description thereof is omitted.(Electrical Configuration of Pump Device according to Second Embodiment)

[0056] As illustrated in FIG. 4, a pump device 120 according to the second embodiment differs in that the pump device 120 includes a temperature sensor 180 and a storage unit 172 of a controller 170 stores first relationship defining data RD1 and second relationship defining data RD2. The pump device 120 according to the second embodiment also differs in that the controller 170 controls drive frequencies of a first drive circuit D3 and a second drive circuit D4 of a driver 150. Configurations other than these points are the same as those of the pump device 20 according to the first embodiment, and thus the description thereof is omitted.

[0057] The pump device 120 according to the second embodiment includes the temperature sensor 180. The temperature sensor 180 is housed in the housing 21 of the pump device 120. The temperature sensor 180 detects an environmental temperature Tp, which is the ambient temperature of the first pump P1. As described above, the first pump P1 and the second pump P2 are housed in the same housing 21. Thus, the environmental temperature Tp is also the ambient temperature of the second pump P2.

[0058] In the second embodiment, the storage unit 172 of the controller 170 stores the first relationship defining data RD1 and the second relationship defining data RD2. The first relationship defining data RD1 is data defining a relationship between the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the first pump P1. The second relationship defining data RD2 is data defining a relationship between the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the second pump P2. Each piece of relationship defining data is, for example, map data in a table format, a regression equation obtained by regression analysis, or the like. A method for creating each piece of relationship defining data will be described below.

[0059] In the second embodiment, an arithmetic processing unit 171 of the controller 170 is capable of controlling a drive frequency of AC power to be supplied to the first pump P1 and the second pump P2. Specifically, the arithmetic processing unit 171 of the controller 170 inputs a PWM signal defined at a predetermined first drive frequency f1 to the first drive circuit D3 of the driver 150. The PWM signal is inputted to each switching element of an H-bridge circuit included in the first drive circuit D3. Accordingly, each switching element is switched on and off based on the first drive frequency f1. That is, the first drive circuit D3 is a so-called separately excited oscillation circuit. Thus, AC power that oscillates based on the first drive frequency f1 is outputted from a pair of output terminals of the first drive circuit D3.

[0060] Further, the arithmetic processing unit 171 of the controller 170 inputs a PWM signal defined at a predetermined second drive frequency f2 to the second drive circuit D4. The PWM signal is inputted to each switching element of an H-bridge circuit included in the second drive circuit D4. Accordingly, each switching element is switched on and off based on the second drive frequency f2. That is, the second drive circuit D4 is a so-called separately excited oscillation circuit. Thus, AC power that oscillates based on the second drive frequency f2 is outputted from a pair of output terminals of the second drive circuit D4.(Switching Control According to Second Embodiment)

[0061] Switching control according to the second embodiment differs from the switching control according to the first embodiment in that the acquisition process includes acquiring the environmental temperature Tp and acquiring the impedance values of the respective pumps using the first relationship defining data RD1 and the second relationship defining data RD2. Thus, the description of processing similar to that of the first embodiment is omitted.

[0062] In the second embodiment, when the switching control is started, the arithmetic processing unit 171 performs an acquisition process. In the acquisition process, the arithmetic processing unit 171 acquires the environmental temperature Tp detected by the temperature sensor 180. Subsequently, the arithmetic processing unit 171 inputs the environmental temperature Tp to the first relationship defining data RD1. Accordingly, the arithmetic processing unit 171 acquires an impedance value of the first pump P1 corresponding to the environmental temperature Tp. The arithmetic processing unit 171 also inputs the environmental temperature Tp to the second relationship defining data RD2. Accordingly, the arithmetic processing unit 171 acquires an impedance value of the second pump P2 corresponding to the environmental temperature Tp. In the identification process according to the second embodiment, the specific pump is identified using the impedance values acquired based on the respective pieces of relationship defining data. Subsequent processing of the switching control according to the second embodiment is the same as the processing of the comparison process S12 to the driving process S14 in the switching control according to the first embodiment.(Feedback Control of Relationship Defining Data)

[0063] In the second embodiment, the arithmetic processing unit 171 of the controller 170 is capable of executing feedback control. The feedback control is executed at a predetermined timing during driving of the pump device 120. For example, the feedback control is executed after several minutes have elapsed from the start of driving of the pump device 120. In the feedback control, the arithmetic processing unit 171 of the controller 170 updates the first relationship defining data RD1 and the second relationship defining data RD2.

[0064] As illustrated in FIG. 5, when the feedback control is started, the arithmetic processing unit 171 performs an update data acquisition process S20. In the update data acquisition process S20, the arithmetic processing unit 171 of the controller 170 calculates the impedance value of the first pump P1 and the impedance value of the second pump P2.

[0065] Specifically, as illustrated in FIG. 4, the arithmetic processing unit 171 acquires the drive voltage Vp outputted by the power conversion circuit 51. The arithmetic processing unit 171 further acquires a first drive current Ip1 inputted from the first drive circuit D3 to the first pump P1 and a second drive current Ip2 inputted from the second drive circuit D4 to the second pump P2. The arithmetic processing unit 171 divides the drive voltage Vp by the first drive current Ip1 to calculate the impedance value of the first pump P1. The arithmetic processing unit 171 divides the drive voltage Vp by the second drive current Ip2 to calculate the impedance value of the second pump P2. The arithmetic processing unit 171 also acquires the environmental temperature Tp detected by the temperature sensor 180.

[0066] After the update data acquisition process S20, the arithmetic processing unit 171 performs an update process S21. In the update process S21, the arithmetic processing unit 171 updates the first relationship defining data RD1, based on the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the first pump P1 calculated in the update data acquisition process S20 when the environmental temperature Tp is detected. For example, when the first relationship defining data RD1 is map data, the arithmetic processing unit 171 updates the impedance value of the first pump P1 with respect to the acquired environmental temperature Tp. When the first relationship defining data RD1 is a regression equation obtained by regression analysis, the arithmetic processing unit 171 calculates the regression equation using the acquired environmental temperature Tp and the impedance value of the first pump P1.

[0067] In the update process S21, the arithmetic processing unit 171 further updates the second relationship defining data RD2, based on the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the second pump P2 calculated in the update data acquisition process S20 when the environmental temperature Tp is detected. A specific method for updating the second relationship defining data RD2 is similar to the method for updating the first relationship defining data RD1. With the above feedback control, the arithmetic processing unit 171 of the controller 170 can update the first relationship defining data RD1 and the second relationship defining data RD2.(Operation of Second Embodiment)

[0068] In the second embodiment, the arithmetic processing unit 171 of the controller 170 acquires the environmental temperature Tp, and acquires the impedance values of the respective pumps using the first relationship defining data RD1 and the second relationship defining data RD2. The arithmetic processing unit 171 identifies a specific pump, based on the impedance values derived from these pieces of relationship defining data.(Effects of Second Embodiment)

[0069] According to the second embodiment, in addition to the above-described effects (1-1) to (1-3) of the first embodiment, the following effects are achieved. (2-1) In the second embodiment, the arithmetic

[0070] (2-1) In the second embodiment, the arithmetic processing unit 171 of the controller 170 inputs the environmental temperature Tp to the first relationship defining data RD1 and the second relationship defining data RD2 to acquire the respective impedance values. The magnitude relationship between the impedance values of the respective pumps can be identified by using the environmental temperature Tp, which correlates with the impedance values. On the other hand, since the drive voltage Vp and the respective drive currents, whose values are susceptible to variations caused by external noise, are not used directly for calculation of the impedance values, it is possible to prevent erroneous identification of the specific pump due to external noise or the like.

[0071] (2-2) In the second embodiment, the arithmetic processing unit 171 of the controller 170 is capable of executing feedback control. The variation characteristics of the impedance value of a pump with respect to the environmental temperature Tp may change over time according to a usage status such as a total usage time of the pump. Thus, even if the above characteristics of pumps have changed due to temporal changes or the like of the pump device 120, the arithmetic processing unit 171 executes feedback control, thereby enabling more accurate identification of the magnitude relationship between the impedance values.

[0072] (2-3) In the above-described embodiment, the arithmetic processing unit 171 of the controller 170 controls the drive frequencies of the respective pumps. That is, the first drive circuit D3 and the second drive circuit D4 are separately excited oscillation circuits. Accordingly, the configurations of the respective circuits can be simplified. In addition, since circuit elements required for generating the respective drive frequencies can be omitted in the separately excited oscillation circuits, the pump device 120 can be reduced in size.Modifications

[0073] The above-described embodiments and the following modifications may be implemented in combination with each other as long as no technical contradiction arises.

[0074] The pump device 20 is not limited to being applied to the nebulizer 10. The technology relating to the pump device 20 described above is applicable to any device that uses two or more pumps connected in parallel with each other on an electric power supply path. For example, the pump device 20 may be a pressurization pump, a pMDI (pressurized Metered Dose Inhaler), a sphygmomanometer, or the like.

[0075] The specific type of the first pump P1 is not limited to that in the example of the above-described embodiment. For example, the first pump P1 is not limited to a pump capable of pumping a gas. It is sufficient that at least a fluid be pumpable, and the first pump P1 may be an electric pump capable of pumping a liquid. The same applies to the second pump P2.

[0076] The first pump P1 and the second pump P2 need not be the same in type and specifications. It is sufficient that the first pump P1 and the second pump P2 be connectable in parallel with each other on an electric power supply path from the driver 50.

[0077] The first pump P1 and the second pump P2 need not be arranged in series on a gas flow path. For example, the first pump P1 and the second pump P2 may be arranged in parallel on the gas flow path.

[0078] The configuration of the driver 50 is not limited to that in the example of the above-described embodiment. For example, the driver 50 may have only one drive circuit. In this case, it is sufficient that the first pump P1 and the second pump P2 be connected in parallel with each other to a pair of output terminals of an H-bridge circuit of the drive circuit. Even in this case, the first pump P1 and the second pump P2 can be considered to be arranged in parallel on an electric power supply path.

[0079] For example, the driver 50 may be an inverter. In this case, for example, it is sufficient that a DC voltage inputted from the power supply device PU be converted into an AC voltage having a predetermined effective value to drive each pump.

[0080] The power conversion circuit 51 is not limited to that in the example of the above-described embodiment. For example, the power conversion circuit 51 need not be a step-up converter. The power conversion circuit 51 may be modified as appropriate according to the specifications of the pumps and the circuit configuration of each drive circuit.

[0081] In the above-described embodiment, substantially the same drive voltage Vp is applied to the first pump P1 and the second pump P2. However, it is sufficient that the same drive voltage Vp be supplied from the power conversion circuit 51 to each drive circuit. That is, for example, when a resistive element is present between the first drive circuit D1 and the first pump P1 and no resistive element is present between the second drive circuit D2 and the second pump P2, the drive voltage Vp for the first pump P1 and the drive voltage Vp for the second pump P2 are different. Even in such a case, it is sufficient that the first pump P1 and the second pump P2 be connected in parallel with each other on an electric power supply path from the driver 50.

[0082] It is sufficient that the switching control be executed at least once during a continuous period in which electric power is supplied to the pump device 20. For example, control may be performed to execute driving control when the environmental temperature Tp falls within a predetermined temperature range. Examples of the predetermined range include a range greater than or equal to a predetermined temperature and a range less than or equal to a predetermined temperature.

[0083] In the switching control, the comparison process S12 and the switching process S13 may be omitted. In this case, it is sufficient that the driving process S14 be performed with the specific pump identified in the identification process S11 being designated as a control target. In this case, information indicating the specific pump designated as the control target is not stored in the storage unit 72. In this modification, accordingly, it is sufficient that a predetermined pump be designated as the control target until the first switching control is executed after the pump device 20 starts driving.

[0084] The “prescribed current value” in the driving process S14 need not be a rated current. The prescribed current value may be smaller than the rated current, or may be a current value exceeding the rated current.

[0085] In the second embodiment, a single temperature sensor 180 may be used, or an individual temperature sensor 180 may be provided for each pump to detect the environmental temperature Tp of the corresponding pump.

[0086] In the switching control, acquiring the impedance value of the first pump P1 and the impedance value of the second pump P2 is not essential. For example, in the identification process S11, a pump having a minimum impedance value may be identified based on relationship defining data defining a relationship between the environmental temperature Tp and the pump having the minimum impedance value.

[0087] In the acquisition process S10 according to the second embodiment, the impedance value of each pump may be acquired based on another parameter in addition to the environmental temperature Tp. In this case, it is sufficient that the storage unit 172 of the controller 170 store relationship defining data defining a relationship of the impedance value with respect to the environmental temperature Tp and the other parameter.

[0088] The execution timing of feedback control is not limited to that in the example of the above-described embodiment. For example, the feedback control may be executed immediately after the start of driving of the pump device 120, or may be repeatedly executed at intervals of a predetermined control cycle.

[0089] The content of the first relationship defining data RD1 is not limited to that in the example of the above-described embodiment. For example, the first relationship defining data RD1 may be a multiple regression equation using the environmental temperature Tp and the drive voltage Vp as explanatory variables. The first relationship defining data RD1 may be a machine learning model trained by machine learning to output an impedance value of the first pump P1 with the environmental temperature Tp and the drive voltage Vp as inputs. In any case, it is sufficient that a value corresponding to the impedance value of each pump be acquired in the acquisition process S10.Appendix

[0090] Technical ideas that can be understood from the above-described embodiments and modifications will be described.

[0091] [1] A pump device including: a first pump that is an electric pump capable of pumping a fluid; a second pump that is an electric pump capable of pumping a fluid; a driver capable of converting an input voltage and supplying electric power to the first pump and the second pump; and a controller configured to control the driver, wherein the first pump and the second pump are connected in parallel with each other on an electric power supply path from the driver, and the controller is capable of executing: an identification process for identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump; and a driving process for controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

[0092] [2] The pump device according to [1], wherein at a start of driving of the first pump and the second pump, an impedance value of the first pump is greater than an impedance value of the second pump, and after a predetermined time elapses from the start of driving, the impedance value of the first pump is smaller than the impedance value of the second pump.

[0093] [3] The pump device according to [1] or [2], wherein the controller is capable of executing an acquisition process for acquiring an impedance value of the first pump and an impedance value of the second pump, and the identification process includes identifying the specific pump, based on the impedance value of the first pump and the impedance value of the second pump acquired in the acquisition process.

[0094] [4] The pump device according to [3], further including a temperature sensor configured to detect an environmental temperature around the pumps, wherein the controller stores first relationship defining data defining a relationship between the environmental temperature and the impedance value of the first pump, and second relationship defining data defining a relationship between the environmental temperature and the impedance value of the second pump, and the acquisition process includes inputting the environmental temperature detected by the temperature sensor to the first relationship defining data and the second relationship defining data to acquire the impedance value of the first pump and the impedance value of the second pump.

[0095] [5] The pump device according to [4], wherein the controller is further capable of executing: an update data acquisition process for calculating the impedance value of the first pump, based on a drive voltage of the first pump and the drive current of the first pump; and an update process for updating the first relationship defining data, based on the environmental temperature detected by the temperature sensor and the impedance value of the first pump calculated in the update data acquisition process when the environmental temperature is detected.

[0096] [6] The pump device according to any one of [1] to [5], wherein the controller is capable of controlling a drive frequency of AC power to be supplied to the first pump and the second pump.

[0097] [7] A program for a pump device, the pump device including: a first pump that is an electric pump capable of pumping a fluid; a second pump that is an electric pump capable of pumping a fluid; a driver capable of converting an input voltage and supplying electric power to the first pump and the second pump; and a controller configured to control the driver, the first pump and the second pump being connected in parallel with each other on an electric power supply path from the driver, the program enabling the controller to execute: an identification process for identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump; and a driving process for controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

[0098] 10 nebulizer

[0099] 20 pump device

[0100] 21 housing

[0101] P1 first pump

[0102] P2 second pump

[0103] 50 driver

[0104] 51 power conversion circuit

[0105] D1 first drive circuit

[0106] D2 second drive circuit

[0107] 70 controller

[0108] Vp drive voltage

[0109] Ip1 first drive current

[0110] Ip2 second drive current

[0111] 120 pump device

[0112] 150 driver

[0113] D3 first drive circuit

[0114] D4 second drive circuit

[0115] 170 controller

[0116] f1 first drive frequency

[0117] f2 second drive frequency

[0118] RD1 first relationship defining data

[0119] RD2 second relationship defining data

[0120] PG program

[0121] 180 temperature sensor

[0122] Tp environmental temperature

Examples

first embodiment

(Operation of First Embodiment)

[0049]As described above, the variation characteristics of the impedance values of pumps with respect to the environmental temperature vary from one individual pump to another. Thus, as the environmental temperature changes, the magnitude relationship between the impedance values of the respective pumps may be reversed.

[0050]For example, it is assumed here that the arithmetic processing unit 71 controls the driver 50 with only the first pump P1 being designated as a pump to be controlled, such that the first drive current Ip1 is equal to the rated current. In this case, when the impedance value of the second pump P2 is smaller than the impedance value of the first pump P1, a current larger than the rated current assumed as the current flowing through the second pump P2 may flow.

[0051]According to the above-described embodiment, in the identification process S11, the arithmetic processing unit 71 of the controller 70 identifies a specific pump having a ...

second embodiment

(Operation of Second Embodiment)

[0068]In the second embodiment, the arithmetic processing unit 171 of the controller 170 acquires the environmental temperature Tp, and acquires the impedance values of the respective pumps using the first relationship defining data RD1 and the second relationship defining data RD2. The arithmetic processing unit 171 identifies a specific pump, based on the impedance values derived from these pieces of relationship defining data.

(Effects of Second Embodiment)

[0069]According to the second embodiment, in addition to the above-described effects (1-1) to (1-3) of the first embodiment, the following effects are achieved. (2-1) In the second embodiment, the arithmetic[0070](2-1) In the second embodiment, the arithmetic processing unit 171 of the controller 170 inputs the environmental temperature Tp to the first relationship defining data RD1 and the second relationship defining data RD2 to acquire the respective impedance values. The magnitude relationship...

CROSS REFERENCE TO RELATED APPLICATION

[0001] This is a continuation of International Application No. PCT / JP 2024 / 040556 filed on Nov. 15, 2024 which claims priority from Japanese Patent Application No. 2023-208568 filed on Dec. 11, 2023. The contents of these applications are incorporated herein by reference in their entireties.BACKGROUND OF THE DISCLOSUREField of the Disclosure

[0002] The present disclosure relates to a pump device and a program for the pump device.Description of the Related Art

[0003] A pump device disclosed in Japanese Patent No. 7219722 includes a driver, a first pump, a second pump, and a controller. The driver performs voltage conversion on electric power supplied from a power supply and supplies the electric power to the first pump and the second pump. The first pump and the second pump are piezoelectric pumps and are capable of pumping a gas. The first pump and the second pump are connected in parallel with each other on an electric power supply path from the driver. That is, substantially the same drive voltage is applied to the first pump and the second pump. The controller controls a drive voltage to be supplied from the driver to each pump.BRIEF SUMMARY OF THE DISCLOSURE

[0004] In a pump device such as that disclosed in Japanese Patent No. 7219722, the variation characteristics of the impedance value of each pump with respect to the environmental temperature differ from one individual to another. Thus, for example, when a drive voltage is controlled based on the impedance value of one pump, a current larger than assumed may flow through the other pump depending on the environmental temperature.

[0005] To solve the above problem, the present disclosure provides a pump device including: a first pump that is an electric pump capable of pumping a fluid; a second pump that is an electric pump capable of pumping a fluid; a driver capable of converting an input voltage and supplying electric power to the first pump and the second pump; and a controller configured to control the driver, wherein the first pump and the second pump are connected in parallel with each other on an electric power supply path from the driver, and the controller is capable of executing: an identification process for identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump; and a driving process for controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

[0006] The present disclosure also provides a program for a pump device, the pump device including a first pump that is an electric pump capable of pumping a fluid, a second pump that is an electric pump capable of pumping a fluid, a driver capable of converting an input voltage and supplying electric power to the first pump and the second pump, and a controller configured to control the driver, the first pump and the second pump being connected in parallel with each other on an electric power supply path from the driver, the program enabling the controller to execute an identification process for identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump, and a driving process for controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

[0007] It is possible to suppress an unexpectedly large current from flowing through a pump.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0008] FIG. 1 is a perspective view of a nebulizer.

[0009] FIG. 2 is a schematic configuration diagram of a pump device according to a first embodiment.

[0010] FIG. 3 is a flowchart of switching control.

[0011] FIG. 4 is a schematic configuration diagram of a pump device according to a second embodiment.

[0012] FIG. 5 is a flowchart of feedback control.DETAILED DESCRIPTION OF THE DISCLOSURE

[0013] A first embodiment and a second embodiment of a pump device and a program for the pump device will be described hereinafter. In each embodiment, the pump device is applied to a nebulizer. The drawings may illustrate components on an enlarged scale to facilitate understanding. Dimensional ratios of the components may differ from actual ones or from those in other drawings.First Embodiment of Pump Device and Program for Pump Device(Overall Configuration of Nebulizer)

[0014] As illustrated in FIG. 1, a nebulizer 10 includes a pump device 20, a tank unit 30, and a discharge unit 40.

[0015] The pump device 20 includes a housing 21, a first pump P1, and a second pump P2. The housing 21 has a substantially cylindrical appearance. Further, the housing 21 has a hollow portion therein. In the following description, an axis parallel to a central axis of the housing 21 is defined as a reference axis AX. One direction parallel to the reference axis AX is defined as an upward direction UD, and a direction opposite to the upward direction UD is defined as a downward direction DD.

[0016] The first pump P1 is an electric pump. The first pump P1 is located in the housing 21. Specifically, the first pump P1 is a micro blower using a piezoelectric element. This micro blower may also be referred to as a piezoelectric pump, an air pump, or the like. Although not illustrated, the first pump P1 has a diaphragm, a piezoelectric element, an inlet, and an outlet. The diaphragm is a thin film having elasticity. The piezoelectric element is attached to the diaphragm. The piezoelectric element is ceramic. When a voltage is applied to the piezoelectric element, the piezoelectric element undergoes flexural vibration. The diaphragm repeatedly undergoes bending deformation in conjunction with the flexural vibration of the piezoelectric element, thereby causing a gas sucked from the inlet to be pumped from the outlet. Thus, the first pump P1 is capable of pumping a gas. The first pump P1 is also capable of atomizing a liquid by spraying the pumped gas onto the liquid.

[0017] Within the housing 21, the outlet of the first pump P1 faces in the upward direction UD. The outlet of the first pump P1 communicates with the outside of the pump device 20 through an upward-direction-UD-side end face of the pump device 20. Thus, the gas discharged through the outlet of the first pump P1 is discharged in the upward direction UD of the housing 21. The inlet of the first pump P1 faces in the downward direction DD.

[0018] The second pump P2 is an electric pump. The second pump P2 is located in the housing 21. The second pump P2 is a pump complying with the same specifications as the first pump P1. That is, the second pump P2 is a micro blower using a piezoelectric element. Thus, the second pump P2 is capable of pumping a gas.

[0019] Within the housing 21, an outlet of the second pump P2 faces in the upward direction UD. The outlet of the second pump P2 is connected to the inlet of the first pump P1. That is, the first pump P1 and the second pump P2 are connected in series on a gas flow path. Thus, the gas pumped from the outlet of the second pump P2 is sucked into the first pump P1. The gas sucked into the first pump P1 is increased in pressure and flow rate and pumped by the first pump P1.

[0020] The variation characteristics of the impedance value of each pump with respect to the environmental temperature differ from one individual pump to another. This is attributable to manufacturing errors of each pump, temporal changes after manufacture, and the like. That is, even at the same environmental temperature, the impedance value of the first pump P1 and the impedance value of the second pump P2 may have a magnitude relationship. Furthermore, as the environmental temperature changes, the magnitude relationship between the impedance value of the first pump P1 and the impedance value of the second pump P2 may be reversed. The environmental temperature refers to the ambient temperature of each pump. The impedance value refers to the absolute value of impedance.

[0021] As illustrated in FIG. 1, the tank unit 30 is attached to the upward direction UD side of the pump device 20. The tank unit 30 includes a tank body 31 and an atomizing nozzle (not illustrated).

[0022] The tank body 31 is substantially cylindrical and has a bottom surface. That is, one end face of the tank body 31 is open. In a state in which the tank unit 30 is attached to the pump device 20, the opening of the tank body 31 faces in the upward direction UD. Thus, the tank body 31 can store a liquid medicine or the like.

[0023] The atomizing nozzle (not illustrated) is attached to the bottom surface of the tank body 31 within the tank body 31. The atomizing nozzle has an air blowing nozzle and a water suction nozzle, which are not illustrated. The air blowing nozzle is a through hole extending along the reference axis AX. The air blowing nozzle is connected to the outlet of the first pump P1. Thus, the gas pumped by the first pump P1 is discharged through the air blowing nozzle of the atomizing nozzle. The water suction nozzle supplies a liquid stored at the bottom of the tank body 31 to the vicinity of an open end of the air blowing nozzle. Thus, the liquid that has reached the vicinity of the air blowing nozzle through the water suction nozzle is sprayed with the gas pumped by the first pump P1 and the second pump P2 of the pump device 20 and becomes mist.

[0024] As illustrated in FIG. 1, the discharge unit 40 is attached to the upward direction UD side of the tank unit 30. The discharge unit 40 includes a case 41, an intake hole 42, and a discharge nozzle 43. The case 41 is substantially cylindrical, with one end face being open and the other end face being closed. The opening of the case 41 is fitted into the opening of the tank body 31. Thus, an internal space is defined by the tank body 31 and the case 41.

[0025] The intake hole 42 is a through hole that penetrates a surface of the case 41 that faces in the upward direction UD. That is, the intake hole 42 allows the internal space of the case 41 to communicate with the external space thereof.

[0026] The discharge nozzle 43 is a tube protruding from a side surface of the case 41. The discharge nozzle 43 is located in the vicinity of an upward-direction-UD-side end of the side surface of the case 41. One end of the discharge nozzle 43 is connected to the internal space of the case 41. Thus, the liquid atomized by the pump device 20 and the tank unit 30 is discharged from the discharge nozzle 43 through the internal space defined by the case 41 and the tank body 31.(Electrical Configuration of Pump Device according to First Embodiment)

[0027] As illustrated in FIG. 2, the pump device 20 of the nebulizer 10 includes a driver 50 and a controller 70. The driver 50 and the controller 70 are housed in the housing 21 of the pump device 20.

[0028] The driver 50 includes a power conversion circuit 51, a first drive circuit D1, and a second drive circuit D2. The driver 50 is capable of converting a voltage from an external power supply device PU and supplying electric power to the first pump P1 and the second pump P2. The power supply device PU may be a secondary battery housed in the housing 21 of the pump device 20.

[0029] The power conversion circuit 51 is connected to the power supply device PU. The power conversion circuit 51 converts a DC voltage inputted from the power supply device PU and outputs a drive voltage Vp. Specifically, the power conversion circuit 51 is a step-up converter. The power conversion circuit 51 has a plurality of switching elements (not illustrated). The plurality of switching elements are, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The power conversion circuit 51 converts the DC voltage inputted from the power supply device PU into a voltage having a predetermined voltage value by switching on and off the plurality of switching elements. The power conversion circuit 51 outputs the converted voltage as the drive voltage Vp.

[0030] The first drive circuit D1 is connected between the power conversion circuit 51 and the first pump P1. Specifically, the first drive circuit D1 includes an H-bridge circuit (not illustrated). The H-bridge circuit includes an input terminal and a pair of output terminals. The input terminal of the H-bridge circuit is connected to the power conversion circuit 51. The pair of output terminals of the H-bridge circuit is connected to the first pump P1. The pair of output terminals output voltages having the same absolute value and opposite phases at a predetermined drive frequency. Thus, the first drive circuit D1 converts the DC voltage supplied from the power conversion circuit 51 into AC power and supplies the AC power to the first pump P1.

[0031] When electric power is supplied from the first drive circuit D1 to the first pump P1, the piezoelectric element of the first pump P1 is excited. That is, the first pump P1 is driven. In the present embodiment, the first drive circuit D1 is a self-excited oscillation circuit. That is, the first drive circuit D1 controls, within the first drive circuit D1, the drive frequency of the AC voltage to be applied to the first pump P1, independently of external control.

[0032] The second drive circuit D2 is connected between the power conversion circuit 51 and the second pump P2. Specifically, the second drive circuit D2 includes an H-bridge circuit (not illustrated). The H-bridge circuit includes an input terminal and a pair of output terminals. The input terminal of the H-bridge circuit is connected to the power conversion circuit 51. The pair of output terminals of the H-bridge circuit is connected to the second pump P2. Thus, the second drive circuit D2 converts the DC voltage supplied from the power conversion circuit 51 into AC power and supplies the AC power to the second pump P2.

[0033] When electric power is supplied from the second drive circuit D2 to the second pump P2, the piezoelectric element of the second pump P2 is excited. That is, the second pump P2 is driven. In the present embodiment, the second drive circuit D2 is a self-excited oscillation circuit.

[0034] As described above, the first pump P1 and the second pump P2 are connected to the same power conversion circuit 51 via the corresponding drive circuits. That is, the first pump P1 and the second pump P2 are connected in parallel with each other on an electric power supply path from the driver 50. More specifically, substantially the same drive voltage Vp is applied to the first pump P1 and the second pump P2 from the driver 50.

[0035] The controller 70 is housed in the housing 21 of the pump device 20. The controller 70 controls the driver 50. Specifically, the controller 70 has an arithmetic processing unit 71 and a storage unit 72.

[0036] The storage unit 72 of the controller 70 stores a predetermined program PG in advance. The arithmetic processing unit 71 of the controller 70 is capable of executing the program PG. That is, the controller 70 is an MCU (Microcontroller Unit). The arithmetic processing unit 71 of the controller 70 executes the program PG to control the power conversion circuit 51 of the driver 50. Specifically, the arithmetic processing unit 71 inputs a PWM (Pulse Width Modulation) signal to gate terminals of the plurality of switching elements of the power conversion circuit 51. Accordingly, the on / off states of the respective switching elements are switched. Consequently, the magnitude of the drive voltage Vp to be outputted by the power conversion circuit 51 is controlled.(Switching Control According to First Embodiment)

[0037] When electric power is supplied from the power supply device PU to the pump device 20, the power conversion circuit 51 of the driver 50 applies the drive voltage Vp to the first pump P1 and the second pump P2 through the first drive circuit D1 and the second drive circuit D2, respectively. Thereafter, the arithmetic processing unit 71 of the controller 70 executes the program PG stored in the storage unit 72 to start switching control. The switching control is a control method for controlling the driver 50 such that an identification process S11 is performed to identify, as a specific pump, a pump having a minimum impedance value from among the first pump P1 and the second pump P2 and such that a drive current to be supplied to the first pump P1 and the second pump P2 has a value less than or equal to a prescribed current value determined in advance for the specific pump. The arithmetic processing unit 71 of the controller 70 repeatedly executes the switching control at intervals of a predetermined time.

[0038] Immediately before starting the switching control, the arithmetic processing unit 71 controls the power conversion circuit 51 of the driver 50, with one of the first pump P1 and the second pump P2 being designated as a pump to be controlled. The pump to be controlled is the specific pump identified by the identification process S11 described below in the preceding switching control. In the switching control performed when electric power is first supplied to the pump device 20 after manufacture of the pump device 20, the arithmetic processing unit 71 controls the power conversion circuit 51, with a pump determined in advance from among the first pump P1 and the second pump P2 being designated as a pump to be controlled. The pump to be controlled is controlled in accordance with a driving process S14 described below.

[0039] As illustrated in FIG. 3, when the switching control is started, the arithmetic processing unit 71 of the controller 70 executes an acquisition process S10. In the acquisition process S10, the controller 70 acquires the impedance value of the first pump P1 and the impedance value of the second pump P2.

[0040] Specifically, as illustrated in FIG. 2, the arithmetic processing unit 71 acquires the drive voltage Vp outputted by the power conversion circuit 51. The arithmetic processing unit 71 further acquires a first drive current Ip1 inputted from the first drive circuit D1 to the first pump P1 and a second drive current Ip2 inputted from the second drive circuit D2 to the second pump P2. Subsequently, the arithmetic processing unit 71 divides the drive voltage Vp by the first drive current Ip1 to calculate the impedance value of the first pump P1. The arithmetic processing unit 71 divides the drive voltage Vp by the second drive current Ip2 to calculate the impedance value of the second pump P2.

[0041] As described above, the variation characteristics of the impedance value of each pump with respect to the environmental temperature differ from one individual pump to another. Thus, when the environmental temperature changes, the magnitude relationship between the impedance value of the first pump P1 and the impedance value of the second pump P2 may be reversed. That is, at the start of driving of the first pump P1 and the second pump P2, the impedance value of the first pump P1 may be greater than the impedance value of the second pump P2, and after a predetermined time elapses from the start of driving, the impedance value of the first pump P1 may become smaller than the impedance value of the second pump P2. Alternatively, at the start of driving, the impedance value of the second pump P2 may be greater than the impedance value of the first pump P1, and after a predetermined time elapses from the start of driving, the impedance value of the second pump P2 may become smaller than the impedance value of the first pump P1.

[0042] As illustrated in FIG. 3, after the acquisition process S10, the arithmetic processing unit 71 performs the identification process S11. In the identification process S11, a pump having a minimum impedance value from among the first pump P1 and the second pump P2 is identified as the specific pump. Specifically, the impedance value of the first pump P1 and the impedance value of the second pump P2, which are acquired in the acquisition process S10, are compared, and a pump having a smaller impedance value is identified as the specific pump.

[0043] After the identification process S11, the arithmetic processing unit 71 performs a comparison process S12. In the comparison process S12, the arithmetic processing unit 71 determines whether the pump designated as a pump to be controlled at the time when the comparison process S12 is started is the same as the specific pump identified in the identification process S11. In other words, the arithmetic processing unit 71 determines whether the magnitude relationship between the impedance values of the respective pumps is reversed between the time when the preceding switching control is executed and the time when the current switching control is executed.

[0044] If the pump to be controlled and the specific pump are different in the comparison process S12 (S12: YES), the arithmetic processing unit 71 performs a switching process S13. In other words, if the magnitude relationship between the impedance values is reversed between the time when the preceding switching control is executed and the time when the current switching control is executed, the arithmetic processing unit 71 performs the switching process S13. In the switching process S13, the pump to be controlled is switched to the specific pump.

[0045] Specifically, information indicating that the first pump P1 or the second pump P2 identified in the most recent identification process S11 is the pump to be controlled is stored in the storage unit 72. For example, it is assumed that the pump to be controlled at the time when the comparison process S12 is started is the first pump P1 and that the specific pump identified in the identification process S11 is the second pump P2. In this case, the arithmetic processing unit 71 rewrites the information of the pump stored as the specific pump in the storage unit 72 from the first pump P1 to the second pump P2.

[0046] On the other hand, if the pump to be controlled and the specific pump are the same in the comparison process S12 (S12: NO), the arithmetic processing unit 71 maintains the information stored as the specific pump in the storage unit 72 without change.

[0047] After a negative determination is made in the comparison process S12 or after the switching process S13 is performed, the controller 70 performs a driving process S14. In the driving process S14, the arithmetic processing unit 71 controls the drive voltage Vp, based on the impedance value of the specific pump to be controlled. Specifically, the arithmetic processing unit 71 controls the power conversion circuit 51 of the driver 50 such that both the first drive current Ip1 to be supplied to the first pump P1 and the second drive current Ip2 to be supplied to the second pump P2 have values less than or equal to a prescribed current value determined in advance for the specific pump. In the present embodiment, the term “prescribed current value” refers to the value of the rated current of the pump to be controlled. The term “value less than or equal to the prescribed current value” refers to the rated current.

[0048] With the above switching control, the arithmetic processing unit 71 of the controller 70 controls the driver 50 such that the first drive current Ip1 to be supplied to the first pump P1 and the second drive current Ip2 to be supplied to the second pump P2 have values less than or equal to the prescribed current value determined in advance for the specific pump. The series of switching control is repeatedly executed during driving of the pump device 20. Thus, the drive current flowing through the specific pump is maintained at or less than the prescribed current value.(Operation of First Embodiment)

[0049] As described above, the variation characteristics of the impedance values of pumps with respect to the environmental temperature vary from one individual pump to another. Thus, as the environmental temperature changes, the magnitude relationship between the impedance values of the respective pumps may be reversed.

[0050] For example, it is assumed here that the arithmetic processing unit 71 controls the driver 50 with only the first pump P1 being designated as a pump to be controlled, such that the first drive current Ip1 is equal to the rated current. In this case, when the impedance value of the second pump P2 is smaller than the impedance value of the first pump P1, a current larger than the rated current assumed as the current flowing through the second pump P2 may flow.

[0051] According to the above-described embodiment, in the identification process S11, the arithmetic processing unit 71 of the controller 70 identifies a specific pump having a minimum impedance value. In the switching process S13, the arithmetic processing unit 71 stores the specific pump as a control target. Subsequently, in the driving process S14, the arithmetic processing unit 71 controls the driver 50 such that the respective drive currents to be supplied to the first pump P1 and the second pump P2 are equal to the rated current. That is, the specific pump having the minimum impedance value at the time when the switching control is executed is designated as the control target.(Effects of First Embodiment)(1-1) In the first embodiment, the controller 70 controls the drive voltage Vp, with the specific pump having the minimum impedance designated as the control target. That is, the controller 70 designates, as the control target, the specific pump through which current flows most easily. Accordingly, it is possible to suppress an unexpectedly large current from flowing through the pumps connected in parallel with each other, even if the magnitude relationship between the impedances of the respective pumps is reversed due to a change in environmental temperature or the like.

[0053] (1-2) In the first embodiment, the magnitude relationship between the impedance value of the first pump P1 and the impedance value of the second pump P2 is reversed. The pumps having such impedance characteristics are suitable for a configuration that performs switching control.

[0054] (1-3) In the first embodiment, the controller 70 identifies a specific pump, based on the impedance values acquired in the acquisition process S10. Since the impedance values of the respective pumps are directly calculated, it is possible to enhance the accuracy of determination in the comparison process S12 as to whether the magnitude relationship between the impedance values of the respective pumps is reversed.Second Embodiment of Pump Device and Program for Pump Device

[0055] The second embodiment of the pump device and the program for the pump device will be described hereinafter. The overall configuration of the nebulizer 10 according to the second embodiment is the same as the overall configuration of the nebulizer 10 according to the first embodiment, and thus the description thereof is omitted.(Electrical Configuration of Pump Device according to Second Embodiment)

[0056] As illustrated in FIG. 4, a pump device 120 according to the second embodiment differs in that the pump device 120 includes a temperature sensor 180 and a storage unit 172 of a controller 170 stores first relationship defining data RD1 and second relationship defining data RD2. The pump device 120 according to the second embodiment also differs in that the controller 170 controls drive frequencies of a first drive circuit D3 and a second drive circuit D4 of a driver 150. Configurations other than these points are the same as those of the pump device 20 according to the first embodiment, and thus the description thereof is omitted.

[0057] The pump device 120 according to the second embodiment includes the temperature sensor 180. The temperature sensor 180 is housed in the housing 21 of the pump device 120. The temperature sensor 180 detects an environmental temperature Tp, which is the ambient temperature of the first pump P1. As described above, the first pump P1 and the second pump P2 are housed in the same housing 21. Thus, the environmental temperature Tp is also the ambient temperature of the second pump P2.

[0058] In the second embodiment, the storage unit 172 of the controller 170 stores the first relationship defining data RD1 and the second relationship defining data RD2. The first relationship defining data RD1 is data defining a relationship between the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the first pump P1. The second relationship defining data RD2 is data defining a relationship between the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the second pump P2. Each piece of relationship defining data is, for example, map data in a table format, a regression equation obtained by regression analysis, or the like. A method for creating each piece of relationship defining data will be described below.

[0059] In the second embodiment, an arithmetic processing unit 171 of the controller 170 is capable of controlling a drive frequency of AC power to be supplied to the first pump P1 and the second pump P2. Specifically, the arithmetic processing unit 171 of the controller 170 inputs a PWM signal defined at a predetermined first drive frequency f1 to the first drive circuit D3 of the driver 150. The PWM signal is inputted to each switching element of an H-bridge circuit included in the first drive circuit D3. Accordingly, each switching element is switched on and off based on the first drive frequency f1. That is, the first drive circuit D3 is a so-called separately excited oscillation circuit. Thus, AC power that oscillates based on the first drive frequency f1 is outputted from a pair of output terminals of the first drive circuit D3.

[0060] Further, the arithmetic processing unit 171 of the controller 170 inputs a PWM signal defined at a predetermined second drive frequency f2 to the second drive circuit D4. The PWM signal is inputted to each switching element of an H-bridge circuit included in the second drive circuit D4. Accordingly, each switching element is switched on and off based on the second drive frequency f2. That is, the second drive circuit D4 is a so-called separately excited oscillation circuit. Thus, AC power that oscillates based on the second drive frequency f2 is outputted from a pair of output terminals of the second drive circuit D4.(Switching Control According to Second Embodiment)

[0061] Switching control according to the second embodiment differs from the switching control according to the first embodiment in that the acquisition process includes acquiring the environmental temperature Tp and acquiring the impedance values of the respective pumps using the first relationship defining data RD1 and the second relationship defining data RD2. Thus, the description of processing similar to that of the first embodiment is omitted.

[0062] In the second embodiment, when the switching control is started, the arithmetic processing unit 171 performs an acquisition process. In the acquisition process, the arithmetic processing unit 171 acquires the environmental temperature Tp detected by the temperature sensor 180. Subsequently, the arithmetic processing unit 171 inputs the environmental temperature Tp to the first relationship defining data RD1. Accordingly, the arithmetic processing unit 171 acquires an impedance value of the first pump P1 corresponding to the environmental temperature Tp. The arithmetic processing unit 171 also inputs the environmental temperature Tp to the second relationship defining data RD2. Accordingly, the arithmetic processing unit 171 acquires an impedance value of the second pump P2 corresponding to the environmental temperature Tp. In the identification process according to the second embodiment, the specific pump is identified using the impedance values acquired based on the respective pieces of relationship defining data. Subsequent processing of the switching control according to the second embodiment is the same as the processing of the comparison process S12 to the driving process S14 in the switching control according to the first embodiment.(Feedback Control of Relationship Defining Data)

[0063] In the second embodiment, the arithmetic processing unit 171 of the controller 170 is capable of executing feedback control. The feedback control is executed at a predetermined timing during driving of the pump device 120. For example, the feedback control is executed after several minutes have elapsed from the start of driving of the pump device 120. In the feedback control, the arithmetic processing unit 171 of the controller 170 updates the first relationship defining data RD1 and the second relationship defining data RD2.

[0064] As illustrated in FIG. 5, when the feedback control is started, the arithmetic processing unit 171 performs an update data acquisition process S20. In the update data acquisition process S20, the arithmetic processing unit 171 of the controller 170 calculates the impedance value of the first pump P1 and the impedance value of the second pump P2.

[0065] Specifically, as illustrated in FIG. 4, the arithmetic processing unit 171 acquires the drive voltage Vp outputted by the power conversion circuit 51. The arithmetic processing unit 171 further acquires a first drive current Ip1 inputted from the first drive circuit D3 to the first pump P1 and a second drive current Ip2 inputted from the second drive circuit D4 to the second pump P2. The arithmetic processing unit 171 divides the drive voltage Vp by the first drive current Ip1 to calculate the impedance value of the first pump P1. The arithmetic processing unit 171 divides the drive voltage Vp by the second drive current Ip2 to calculate the impedance value of the second pump P2. The arithmetic processing unit 171 also acquires the environmental temperature Tp detected by the temperature sensor 180.

[0066] After the update data acquisition process S20, the arithmetic processing unit 171 performs an update process S21. In the update process S21, the arithmetic processing unit 171 updates the first relationship defining data RD1, based on the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the first pump P1 calculated in the update data acquisition process S20 when the environmental temperature Tp is detected. For example, when the first relationship defining data RD1 is map data, the arithmetic processing unit 171 updates the impedance value of the first pump P1 with respect to the acquired environmental temperature Tp. When the first relationship defining data RD1 is a regression equation obtained by regression analysis, the arithmetic processing unit 171 calculates the regression equation using the acquired environmental temperature Tp and the impedance value of the first pump P1.

[0067] In the update process S21, the arithmetic processing unit 171 further updates the second relationship defining data RD2, based on the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the second pump P2 calculated in the update data acquisition process S20 when the environmental temperature Tp is detected. A specific method for updating the second relationship defining data RD2 is similar to the method for updating the first relationship defining data RD1. With the above feedback control, the arithmetic processing unit 171 of the controller 170 can update the first relationship defining data RD1 and the second relationship defining data RD2.(Operation of Second Embodiment)

[0068] In the second embodiment, the arithmetic processing unit 171 of the controller 170 acquires the environmental temperature Tp, and acquires the impedance values of the respective pumps using the first relationship defining data RD1 and the second relationship defining data RD2. The arithmetic processing unit 171 identifies a specific pump, based on the impedance values derived from these pieces of relationship defining data.(Effects of Second Embodiment)

[0069] According to the second embodiment, in addition to the above-described effects (1-1) to (1-3) of the first embodiment, the following effects are achieved. (2-1) In the second embodiment, the arithmetic

[0070] (2-1) In the second embodiment, the arithmetic processing unit 171 of the controller 170 inputs the environmental temperature Tp to the first relationship defining data RD1 and the second relationship defining data RD2 to acquire the respective impedance values. The magnitude relationship between the impedance values of the respective pumps can be identified by using the environmental temperature Tp, which correlates with the impedance values. On the other hand, since the drive voltage Vp and the respective drive currents, whose values are susceptible to variations caused by external noise, are not used directly for calculation of the impedance values, it is possible to prevent erroneous identification of the specific pump due to external noise or the like.

[0071] (2-2) In the second embodiment, the arithmetic processing unit 171 of the controller 170 is capable of executing feedback control. The variation characteristics of the impedance value of a pump with respect to the environmental temperature Tp may change over time according to a usage status such as a total usage time of the pump. Thus, even if the above characteristics of pumps have changed due to temporal changes or the like of the pump device 120, the arithmetic processing unit 171 executes feedback control, thereby enabling more accurate identification of the magnitude relationship between the impedance values.

[0072] (2-3) In the above-described embodiment, the arithmetic processing unit 171 of the controller 170 controls the drive frequencies of the respective pumps. That is, the first drive circuit D3 and the second drive circuit D4 are separately excited oscillation circuits. Accordingly, the configurations of the respective circuits can be simplified. In addition, since circuit elements required for generating the respective drive frequencies can be omitted in the separately excited oscillation circuits, the pump device 120 can be reduced in size.Modifications

[0073] The above-described embodiments and the following modifications may be implemented in combination with each other as long as no technical contradiction arises.

[0074] The pump device 20 is not limited to being applied to the nebulizer 10. The technology relating to the pump device 20 described above is applicable to any device that uses two or more pumps connected in parallel with each other on an electric power supply path. For example, the pump device 20 may be a pressurization pump, a pMDI (pressurized Metered Dose Inhaler), a sphygmomanometer, or the like.

[0075] The specific type of the first pump P1 is not limited to that in the example of the above-described embodiment. For example, the first pump P1 is not limited to a pump capable of pumping a gas. It is sufficient that at least a fluid be pumpable, and the first pump P1 may be an electric pump capable of pumping a liquid. The same applies to the second pump P2.

[0076] The first pump P1 and the second pump P2 need not be the same in type and specifications. It is sufficient that the first pump P1 and the second pump P2 be connectable in parallel with each other on an electric power supply path from the driver 50.

[0077] The first pump P1 and the second pump P2 need not be arranged in series on a gas flow path. For example, the first pump P1 and the second pump P2 may be arranged in parallel on the gas flow path.

[0078] The configuration of the driver 50 is not limited to that in the example of the above-described embodiment. For example, the driver 50 may have only one drive circuit. In this case, it is sufficient that the first pump P1 and the second pump P2 be connected in parallel with each other to a pair of output terminals of an H-bridge circuit of the drive circuit. Even in this case, the first pump P1 and the second pump P2 can be considered to be arranged in parallel on an electric power supply path.

[0079] For example, the driver 50 may be an inverter. In this case, for example, it is sufficient that a DC voltage inputted from the power supply device PU be converted into an AC voltage having a predetermined effective value to drive each pump.

[0080] The power conversion circuit 51 is not limited to that in the example of the above-described embodiment. For example, the power conversion circuit 51 need not be a step-up converter. The power conversion circuit 51 may be modified as appropriate according to the specifications of the pumps and the circuit configuration of each drive circuit.

[0081] In the above-described embodiment, substantially the same drive voltage Vp is applied to the first pump P1 and the second pump P2. However, it is sufficient that the same drive voltage Vp be supplied from the power conversion circuit 51 to each drive circuit. That is, for example, when a resistive element is present between the first drive circuit D1 and the first pump P1 and no resistive element is present between the second drive circuit D2 and the second pump P2, the drive voltage Vp for the first pump P1 and the drive voltage Vp for the second pump P2 are different. Even in such a case, it is sufficient that the first pump P1 and the second pump P2 be connected in parallel with each other on an electric power supply path from the driver 50.

[0082] It is sufficient that the switching control be executed at least once during a continuous period in which electric power is supplied to the pump device 20. For example, control may be performed to execute driving control when the environmental temperature Tp falls within a predetermined temperature range. Examples of the predetermined range include a range greater than or equal to a predetermined temperature and a range less than or equal to a predetermined temperature.

[0083] In the switching control, the comparison process S12 and the switching process S13 may be omitted. In this case, it is sufficient that the driving process S14 be performed with the specific pump identified in the identification process S11 being designated as a control target. In this case, information indicating the specific pump designated as the control target is not stored in the storage unit 72. In this modification, accordingly, it is sufficient that a predetermined pump be designated as the control target until the first switching control is executed after the pump device 20 starts driving.

[0084] The “prescribed current value” in the driving process S14 need not be a rated current. The prescribed current value may be smaller than the rated current, or may be a current value exceeding the rated current.

[0085] In the second embodiment, a single temperature sensor 180 may be used, or an individual temperature sensor 180 may be provided for each pump to detect the environmental temperature Tp of the corresponding pump.

[0086] In the switching control, acquiring the impedance value of the first pump P1 and the impedance value of the second pump P2 is not essential. For example, in the identification process S11, a pump having a minimum impedance value may be identified based on relationship defining data defining a relationship between the environmental temperature Tp and the pump having the minimum impedance value.

[0087] In the acquisition process S10 according to the second embodiment, the impedance value of each pump may be acquired based on another parameter in addition to the environmental temperature Tp. In this case, it is sufficient that the storage unit 172 of the controller 170 store relationship defining data defining a relationship of the impedance value with respect to the environmental temperature Tp and the other parameter.

[0088] The execution timing of feedback control is not limited to that in the example of the above-described embodiment. For example, the feedback control may be executed immediately after the start of driving of the pump device 120, or may be repeatedly executed at intervals of a predetermined control cycle.

[0089] The content of the first relationship defining data RD1 is not limited to that in the example of the above-described embodiment. For example, the first relationship defining data RD1 may be a multiple regression equation using the environmental temperature Tp and the drive voltage Vp as explanatory variables. The first relationship defining data RD1 may be a machine learning model trained by machine learning to output an impedance value of the first pump P1 with the environmental temperature Tp and the drive voltage Vp as inputs. In any case, it is sufficient that a value corresponding to the impedance value of each pump be acquired in the acquisition process S10.Appendix

[0090] Technical ideas that can be understood from the above-described embodiments and modifications will be described.

[0091] [1] A pump device including: a first pump that is an electric pump capable of pumping a fluid; a second pump that is an electric pump capable of pumping a fluid; a driver capable of converting an input voltage and supplying electric power to the first pump and the second pump; and a controller configured to control the driver, wherein the first pump and the second pump are connected in parallel with each other on an electric power supply path from the driver, and the controller is capable of executing: an identification process for identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump; and a driving process for controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

[0092] [2] The pump device according to [1], wherein at a start of driving of the first pump and the second pump, an impedance value of the first pump is greater than an impedance value of the second pump, and after a predetermined time elapses from the start of driving, the impedance value of the first pump is smaller than the impedance value of the second pump.

[0093] [3] The pump device according to [1] or [2], wherein the controller is capable of executing an acquisition process for acquiring an impedance value of the first pump and an impedance value of the second pump, and the identification process includes identifying the specific pump, based on the impedance value of the first pump and the impedance value of the second pump acquired in the acquisition process.

[0094] [4] The pump device according to [3], further including a temperature sensor configured to detect an environmental temperature around the pumps, wherein the controller stores first relationship defining data defining a relationship between the environmental temperature and the impedance value of the first pump, and second relationship defining data defining a relationship between the environmental temperature and the impedance value of the second pump, and the acquisition process includes inputting the environmental temperature detected by the temperature sensor to the first relationship defining data and the second relationship defining data to acquire the impedance value of the first pump and the impedance value of the second pump.

[0095] [5] The pump device according to [4], wherein the controller is further capable of executing: an update data acquisition process for calculating the impedance value of the first pump, based on a drive voltage of the first pump and the drive current of the first pump; and an update process for updating the first relationship defining data, based on the environmental temperature detected by the temperature sensor and the impedance value of the first pump calculated in the update data acquisition process when the environmental temperature is detected.

[0096] [6] The pump device according to any one of [1] to [5], wherein the controller is capable of controlling a drive frequency of AC power to be supplied to the first pump and the second pump.

[0097] [7] A program for a pump device, the pump device including: a first pump that is an electric pump capable of pumping a fluid; a second pump that is an electric pump capable of pumping a fluid; a driver capable of converting an input voltage and supplying electric power to the first pump and the second pump; and a controller configured to control the driver, the first pump and the second pump being connected in parallel with each other on an electric power supply path from the driver, the program enabling the controller to execute: an identification process for identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump; and a driving process for controlling the driver such that a drive current to be supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

[0098] 10 nebulizer

[0099] 20 pump device

[0100] 21 housing

[0101] P1 first pump

[0102] P2 second pump

[0103] 50 driver

[0104] 51 power conversion circuit

[0105] D1 first drive circuit

[0106] D2 second drive circuit

[0107] 70 controller

[0108] Vp drive voltage

[0109] Ip1 first drive current

[0110] Ip2 second drive current

[0111] 120 pump device

[0112] 150 driver

[0113] D3 first drive circuit

[0114] D4 second drive circuit

[0115] 170 controller

[0116] f1 first drive frequency

[0117] f2 second drive frequency

[0118] RD1 first relationship defining data

[0119] RD2 second relationship defining data

[0120] PG program

[0121] 180 temperature sensor

[0122] Tp environmental temperature

Examples

first embodiment

(Operation of First Embodiment)

[0049]As described above, the variation characteristics of the impedance values of pumps with respect to the environmental temperature vary from one individual pump to another. Thus, as the environmental temperature changes, the magnitude relationship between the impedance values of the respective pumps may be reversed.

[0050]For example, it is assumed here that the arithmetic processing unit 71 controls the driver 50 with only the first pump P1 being designated as a pump to be controlled, such that the first drive current Ip1 is equal to the rated current. In this case, when the impedance value of the second pump P2 is smaller than the impedance value of the first pump P1, a current larger than the rated current assumed as the current flowing through the second pump P2 may flow.

[0051]According to the above-described embodiment, in the identification process S11, the arithmetic processing unit 71 of the controller 70 identifies a specific pump having a ...

second embodiment

(Operation of Second Embodiment)

[0068]In the second embodiment, the arithmetic processing unit 171 of the controller 170 acquires the environmental temperature Tp, and acquires the impedance values of the respective pumps using the first relationship defining data RD1 and the second relationship defining data RD2. The arithmetic processing unit 171 identifies a specific pump, based on the impedance values derived from these pieces of relationship defining data.

(Effects of Second Embodiment)

[0069]According to the second embodiment, in addition to the above-described effects (1-1) to (1-3) of the first embodiment, the following effects are achieved. (2-1) In the second embodiment, the arithmetic[0070](2-1) In the second embodiment, the arithmetic processing unit 171 of the controller 170 inputs the environmental temperature Tp to the first relationship defining data RD1 and the second relationship defining data RD2 to acquire the respective impedance values. The magnitude relationship...

Claims

1. A pump device comprising:a first pump that is an electric pump configured to pump a fluid;a second pump that is an electric pump configured to pump a fluid;a driver configured to convert an input voltage, and to supply electric power to the first pump and the second pump; anda controller configured to control the driver,wherein the first pump and the second pump are connected in parallel with each other on an electric power supply path from the driver, andwherein the controller is configured to:identify, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump; andcontrol the driver such that a drive current supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

2. The pump device according to claim 1,wherein at a start of driving of the first pump and the second pump, an impedance value of the first pump is greater than an impedance value of the second pump, andwherein after a predetermined time elapses from the start of driving, the impedance value of the first pump is less than the impedance value of the second pump.

3. The pump device according to claim 1,wherein the controller is further configured to acquire an impedance value of the first pump and an impedance value of the second pump, andwherein the control is configured to identify the specific pump based on the acquired impedance value of the first pump and the impedance value of the second pump.

4. The pump device according to claim 3, further comprising:a temperature sensor configured to detect an environmental temperature around the first pump and the second pump,wherein the controller is further configured to store first relationship defining data defining a relationship between the environmental temperature and the impedance value of the first pump, and second relationship defining data defining a relationship between the environmental temperature and the impedance value of the second pump, andwherein the controller is configured to acquire the impedance values of the first and second pumps by inputting the environmental temperature detected by the temperature sensor to the first relationship defining data and the second relationship defining data.

5. The pump device according to claim 4, wherein the controller is further configured to:determine the impedance value of the first pump based on a drive voltage of the first pump and the drive current of the first pump; andupdate the first relationship defining data based on the environmental temperature detected by the temperature sensor and the determined impedance value of the first pump when the environmental temperature is detected.

6. The pump device according to claim 1, wherein the controller is further configured to control a drive frequency of AC power supplied to the first pump and the second pump.

7. A method for controlling a pump device, the pump device comprising:a first pump that is an electric pump configured to pump a fluid;a second pump that is an electric pump configured to pump a fluid;a driver configured to convert an input voltage, and to supply electric power to the first pump and the second pump; anda controller configured to control the driver,the first pump and the second pump being connected in parallel with each other on an electric power supply path from the driver,the method comprising:identifying, as a specific pump, a pump having a minimum impedance value from among the first pump and the second pump; andcontrolling the driver such that a drive current supplied to the first pump and the second pump has a value less than or equal to a prescribed current value determined in advance for the specific pump.

8. The method according to claim 7, further comprising:acquiring an impedance value of the first pump and an impedance value of the second pump,wherein the specific pump is identified based on the acquired impedance value of the first pump and the impedance value of the second pump.

9. The method according to claim 8, further comprising:storing first relationship defining data defining a relationship between a detected environmental temperature around the first pump and the second pump, and the impedance value of the first pump, and second relationship defining data defining a relationship between the environmental temperature and the impedance value of the second pump,wherein acquiring the impedance values of the first and second pumps comprises inputting the detected environmental temperature to the first relationship defining data and the second relationship defining data.

10. The method according to claim 9, further comprising:determining the impedance value of the first pump based on a drive voltage of the first pump and the drive current of the first pump; andupdating the first relationship defining data based on the detected environmental temperature and the determined impedance value of the first pump when the environmental temperature is detected.

11. The method according to claim 7, further comprising:controlling a drive frequency of AC power supplied to the first pump and the second pump.

Images