Pump device and program for pump device

Abstract

A pump device (20) comprises a first pump (P1) and a second pump (P2). The pump device (20) also comprises a drive device (50) and a control device (70). The first pump (P1) and the second pump (P2) are connected in parallel with each other on an electric power supply path from the drive device (50). The control device (70) acquires an impedance value of the first pump (P1) and an impedance value of the second pump (P2), and can identify the pump having the minimum impedance value between the first pump (P1) and the second pump (P2) as the specific pump. The control device (70) can control the drive device (50) so that a drive current supplied to the first pump (P1) and the second pump (P2) has a value equal to or less than a specified current value.

Description

Pumping device and program for pumping device

[0001] The present disclosure relates to a pump device and a program for a pump device.

[0002] The pump device disclosed in Patent Document 1 includes a drive device, a first pump, a second pump, and a control device. The drive device converts power supplied from a power source into a voltage and supplies it to the first pump and the second pump. The first pump and the second pump are piezoelectric pumps capable of pumping gas. The first pump and the second pump are connected in parallel to each other on a power supply path from the drive device. In other words, approximately the same drive voltage is applied to the first pump and the second pump. The control device controls the drive voltage supplied to each pump by the drive device.

[0003] Patent No. 7219722

[0004] In a pump device such as that disclosed in Patent Document 1, the impedance value of each pump fluctuates depending on the ambient temperature, and therefore, when the drive voltage is controlled based on the impedance value of one pump, a current larger than expected may flow through the other pump depending on the ambient temperature.

[0005] In order to solve the above problems, the present disclosure provides a pump device comprising: a first electric pump capable of pumping a fluid; a second electric pump capable of pumping a fluid; a drive device capable of converting an input voltage and supplying power to the first pump and the second pump; and a control device that controls the drive device, wherein the first pump and the second pump are connected in parallel to each other on a power supply path from the drive device, and the control device is capable of executing an identification process that identifies the pump of the first pump and the second pump that has the smallest impedance value as a specific pump, and a drive process that controls the drive device so that the drive current passed through the first pump and the second pump is equal to or less than a specified current value that is predetermined for the specific pump.

[0006] The present disclosure also provides a program for a pump device that is applied to a pump device comprising: a first electric pump capable of pumping a fluid; a second electric pump capable of pumping a fluid; a drive unit capable of converting an input voltage and supplying power to the first pump and the second pump; and a control unit that controls the drive unit, wherein the first pump and the second pump are connected in parallel to each other on a power supply path from the drive unit, and that enables the control unit to execute an identification process that identifies the pump of the first pump and the second pump that has the smallest impedance value as a specific pump; and a drive process that controls the drive unit so that the drive current passed through the first pump and the second pump is equal to or less than a specified current value that is predetermined for the specific pump.

[0007] This prevents unexpectedly large currents from flowing through the pump.

[0008] Fig. 1 is a perspective view of a nebulizer. Fig. 2 is a schematic diagram of a pump device in a first embodiment. Fig. 3 is a flowchart of switching control. Fig. 4 is a schematic diagram of a pump device in a second embodiment. Fig. 5 is a flowchart of feedback control.

[0009] Hereinafter, first and second embodiments of a pump device and a program for the pump device will be described. In each embodiment, the pump device is applied to a nebulizer. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from those in the actual drawings or from those in other drawings.

[0010] <First Embodiment of Pump Device and Program for Pump Device> (Overall Configuration of Nebulizer) As shown in FIG. 1 , a nebulizer 10 includes a pump device 20 , a tank unit 30 , and a discharge unit 40 .

[0011] The pump device 20 includes a housing 21, a first pump P1, and a second pump P2. The housing 21 has a generally cylindrical appearance. The housing 21 has an internal cavity. In the following description, an axis parallel to the central axis of the housing 21 is referred to as a reference axis AX. One of the directions parallel to the reference axis AX is referred to as an upward direction UD, and the direction opposite to the upward direction UD is referred to as a downward direction DD.

[0012] The first pump P1 is an electric pump. The first pump P1 is located inside the housing 21. Specifically, the first pump P1 is a micro-blower that uses a piezoelectric element. This micro-blower is sometimes called a piezoelectric pump, an air pump, or the like. Although not shown, the first pump P1 has a diaphragm, a piezoelectric element, an intake port, and an exhaust port. The diaphragm is an elastic thin film. The piezoelectric element is attached to the diaphragm. The piezoelectric element is made of ceramic. When a voltage is applied to the piezoelectric element, the piezoelectric element flexes and vibrates. The diaphragm repeatedly flexes and deforms in conjunction with the flexural vibration of the piezoelectric element, causing gas sucked through the intake port to be pumped out through the exhaust port. Therefore, the first pump P1 can pump gas. Furthermore, the first pump P1 can atomize liquid by spraying the pumped gas onto the liquid.

[0013] The outlet of the first pump P1 faces in the upward direction UD inside the housing 21. The outlet of the first pump P1 communicates with the outside of the pump device 20 from an end face of the pump device 20 on the upward direction UD side. Therefore, the gas discharged from the outlet of the first pump P1 is discharged in the upward direction UD of the housing 21. The intake port of the first pump P1 faces in the downward direction DD.

[0014] The second pump P2 is an electric pump. The second pump P2 is located inside the housing 21. The second pump P2 is a pump of the same specifications as the first pump P1. In other words, the second pump P2 is a micro-blower that uses a piezoelectric element. Therefore, the second pump P2 is capable of pumping gas.

[0015] Inside the housing 21, the outlet of the second pump P2 faces in the upward direction UD. The outlet of the second pump P2 is connected to the intake port of the first pump P1. That is, the first pump P1 and the second pump P2 are connected in series on the gas flow path. Therefore, 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 pumped out with its pressure and flow rate increased by the first pump P1.

[0016] The fluctuation characteristics of the impedance value of each pump with respect to the ambient temperature differ for each individual pump. This is due to manufacturing errors of each pump and changes over time after manufacturing. That is, even at the same ambient temperature, there may be a magnitude relationship between the impedance value of the first pump P1 and the impedance value of the second pump P2. Furthermore, as the ambient temperature changes, the magnitude relationship between the impedance value of the first pump P1 and the impedance value of the second pump P2 may change. The ambient temperature refers to the temperature around each pump. The impedance value refers to the absolute value of the impedance.

[0017] 1, the tank unit 30 is attached to the pump device 20 in the upward direction UD. The tank unit 30 includes a tank body 31 and an atomizing nozzle (not shown).

[0018] The tank body 31 is generally cylindrical and has a bottom surface. That is, one end surface of the tank body 31 is open. When the tank unit 30 is attached to the pump device 20, the opening of the tank body 31 faces upward in the UD direction. Therefore, the tank body 31 can store a liquid medicine or the like.

[0019] The atomizing nozzle (not shown) is attached to the bottom surface of the tank body 31 inside the tank body 31. The atomizing nozzle has an air blowing nozzle and a water suction nozzle (not shown). 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. Therefore, the gas pressurized by the first pump P1 is discharged from the air blowing nozzle of the atomizing nozzle. Furthermore, the water suction nozzle supplies liquid stored at the bottom of the tank body 31 to the vicinity of the open end of the air blowing nozzle. Therefore, the liquid that passes through the water suction nozzle and reaches the vicinity of the air blowing nozzle is atomized by the gas pressurized by the first pump P1 and the second pump P2 of the pump device 20.

[0020] As shown in Fig. 1, the discharge unit 40 is attached to the tank unit 30 in the upward direction UD. The discharge unit 40 includes a case 41, an intake port 42, and a discharge nozzle 43. The case 41 is generally cylindrical with one end open and the other end closed. The opening of the case 41 fits into the opening of the tank body 31. Therefore, the tank body 31 and the case 41 define an internal space.

[0021] The intake hole 42 is a through-hole that penetrates the surface of the case 41 facing the upward direction UD. That is, the intake hole 42 connects the internal space of the case 41 with the external space. The discharge nozzle 43 is a tube that protrudes from the side surface of the case 41. The discharge nozzle 43 is located near the end of the side surface of the case 41 that is on the upward direction UD side. One end of the discharge nozzle 43 is connected to the internal space of the case 41. Therefore, the liquid atomized by the pump device 20 and the tank unit 30 is discharged from the discharge nozzle 43 through the internal space partitioned by the case 41 and the tank body 31.

[0022] 2, the pump device 20 of the nebulizer 10 includes a drive device 50 and a control device 70. The drive device 50 and the control device 70 are housed inside the housing 21 of the pump device 20.

[0023] The drive device 50 includes a power conversion circuit 51, a first drive circuit D1, and a second drive circuit D2. The drive device 50 converts voltage from an external power supply unit PU and supplies power to the first pump P1 and the second pump P2. The power supply unit PU may be a secondary battery stored inside the housing 21 of the pump device 20.

[0024] The power conversion circuit 51 is connected to the power supply unit PU. The power conversion circuit 51 converts a DC voltage input from the power supply unit PU and outputs a drive voltage Vp. Specifically, the power conversion circuit 51 is a boost converter. The power conversion circuit 51 has a plurality of switching elements (not shown). The plurality of switching elements are, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The power conversion circuit 51 converts the DC voltage input from the power supply unit PU into a voltage of a predetermined voltage value by switching the plurality of switching elements on and off. The power conversion circuit 51 then outputs the converted voltage as the drive voltage Vp.

[0025] 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 shown). 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 are connected to the first pump P1. Voltages of the same absolute value but opposite phases are output from the pair of output terminals at a predetermined drive frequency. Therefore, the first drive circuit D1 converts the DC voltage supplied from the power conversion circuit 51 into AC power and supplies it to the first pump P1.

[0026] When 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 this embodiment, the first drive circuit D1 is a self-exciting circuit. That is, the first drive circuit D1 controls the drive frequency of the AC voltage applied to the first pump P1 within the first drive circuit D1 without relying on external control.

[0027] 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 shown). 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 are connected to the second pump P2. Therefore, the second drive circuit D2 converts the DC voltage supplied from the power conversion circuit 51 into AC power and supplies it to the second pump P2.

[0028] When power is supplied from the second drive circuit D2 to the second pump P2, the piezoelectric element of the second pump P2 is excited, i.e., the second pump P2 is driven. Note that in this embodiment, the second drive circuit D2 is a self-oscillating circuit.

[0029] As described above, the first pump P1 and the second pump P2 are connected to the same power conversion circuit 51 via their corresponding drive circuits. That is, the first pump P1 and the second pump P2 are connected in parallel to each other on the power supply path from the drive device 50. More specifically, approximately the same drive voltage Vp is applied to the first pump P1 and the second pump P2 from the drive device 50.

[0030] The control device 70 is housed inside the housing 21 of the pump device 20. The control device 70 controls the drive device 50. Specifically, the control device 70 has an arithmetic processing unit 71 and a storage unit 72.

[0031] The storage unit 72 of the control device 70 stores a predetermined program PG in advance. The arithmetic processing unit 71 of the control device 70 is capable of executing the program PG. In other words, the control device 70 is an MCU (Microcontroller Unit). The arithmetic processing unit 71 of the control device 70 executes the program PG to control the power conversion circuit 51 of the drive device 50. Specifically, the arithmetic processing unit 71 inputs PWM (Pulse Width Modulation) signals to gate terminals of multiple switching elements of the power conversion circuit 51. This switches the on / off state of each switching element. Accordingly, the magnitude of the drive voltage Vp output by the power conversion circuit 51 is controlled.

[0032] Regarding the switching control of the first embodiment, when power is supplied from the power supply unit PU to the pump device 20, the power conversion circuit 51 of the drive device 50 applies a drive voltage Vp to each of the first pump P1 and the second pump P2 via the first drive circuit D1 and the second drive circuit D2. The arithmetic processing unit 71 of the control device 70 then executes a program PG stored in the memory unit 72 to start the switching control. The switching control includes an identification process S11 for identifying the pump with the smallest impedance value as the specific pump among the first pump P1 and the second pump P2, and a control method for controlling the drive device 50 so that the drive currents applied to the first pump P1 and the second pump P2 are equal to or less than a predetermined current value for the specific pump. The arithmetic processing unit 71 of the control device 70 repeatedly executes the switching control at predetermined time intervals.

[0033] Immediately before starting the switching control, the arithmetic processing unit 71 controls the power conversion circuit 51 of the drive device 50, with either the first pump P1 or the second pump P2 as the pump to be controlled. This pump to be controlled is the specific pump identified in the identification process S11, which will be described later, in the previous switching control. However, in switching control when power is supplied to the pump device 20 for the first time since the pump device 20 was manufactured, the arithmetic processing unit 71 controls the power conversion circuit 51 with a predetermined pump, either the first pump P1 or the second pump P2, as the pump to be controlled. The pump to be controlled is controlled in accordance with the drive process S14, which will be described later.

[0034] 3, when the switching control is started, the calculation processing unit 71 of the control device 70 executes an acquisition process S10. In the acquisition process S10, the control device 70 acquires the impedance value of the first pump P1 and the impedance value of the second pump P2.

[0035] 2 , the arithmetic processing unit 71 acquires the drive voltage Vp output by the power conversion circuit 51. The arithmetic processing unit 71 also acquires the first drive current Ip1 input from the first drive circuit D1 to the first pump P1 and the second drive current Ip2 input from the second drive circuit D2 to the second pump P2. Next, the arithmetic processing unit 71 calculates the impedance value of the first pump P1 by dividing the drive voltage Vp by the first drive current Ip1. The arithmetic processing unit 71 calculates the impedance value of the second pump P2 by dividing the drive voltage Vp by the second drive current Ip2.

[0036] As described above, the fluctuation characteristics of the impedance values ​​of each pump with respect to the ambient temperature differ from pump to pump. Therefore, when the ambient temperature changes, the magnitude relationship between the impedance values ​​of the first pump P1 and the second pump P2 may be reversed. That is, when the first pump P1 and the second pump P2 start operating, 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 has elapsed since the start of operation, the impedance value of the first pump P1 may be smaller than the impedance value of the second pump P2. Alternatively, when the first pump P1 and the second pump P2 start operating, 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 has elapsed since the start of operation, the impedance value of the second pump P2 may be smaller than the impedance value of the first pump P1.

[0037] 3, after the acquisition process S10, the calculation processing unit 71 performs an identification process S11. In the identification process S11, the pump having the smallest impedance value among the first pump P1 and the second pump P2 is identified as the identified pump. Specifically, the impedance value of the first pump P1 and the impedance value of the second pump P2 acquired in the acquisition process S10 are compared, and the pump having the smaller impedance value is identified as the identified pump.

[0038] After the identification process S11, the calculation processing unit 71 performs a comparison process S12. In the comparison process S12, the calculation processing unit 71 determines whether the pump to be controlled at the time when the comparison process S12 is started is the same pump as the specific pump identified in the identification process S11. In other words, it determines whether the magnitude relationship of the impedance values ​​of the pumps has changed between the time when the previous switching control was executed and the time when the current switching control is executed.

[0039] If the comparison process S12 determines that the pump to be controlled and the specific pump are different (S12: YES), the calculation processing unit 71 performs switching process S13. In other words, if the magnitude relationship of the impedance values ​​at the time of the previous switching control and the time of the current switching control has been reversed, the calculation processing unit 71 performs switching process S13. In switching process S13, the pump to be controlled is switched to the specific pump.

[0040] 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, assume that the identified pump to be controlled at the time the comparison process S12 is started is the first pump P1 and the identified pump identified in the identification process S11 is the second pump P2. In this case, the calculation processing unit 71 rewrites the information about the pump stored in the storage unit 72 as the identified pump from the first pump P1 to the second pump P2.

[0041] On the other hand, if the comparison step S12 finds that the pump to be controlled is the same as the specific pump (S12: NO), the calculation processing unit 71 maintains the information stored in the storage unit 72 as the specific pump.

[0042] After a negative determination is made in the comparison process S12 or after the switching process S13 is performed, the control device 70 performs the drive process S14. In the drive process S14, the calculation processing unit 71 controls the drive voltage Vp based on the impedance value of the specific pump to be controlled. Specifically, the calculation processing unit 71 controls the power conversion circuit 51 of the drive device 50 so that the first drive current Ip1 passed through the first pump P1 and the second drive current Ip2 passed through the second pump P2 are both equal to or less than a specified current value predetermined for the specific pump. In this embodiment, the "specified current value" refers to the rated current value of the pump to be controlled. The "value equal to or less than the specified current value" refers to the rated current.

[0043] Through the above-described switching control, the calculation processing unit 71 of the control device 70 controls the drive device 50 so that the first drive current Ip1 passed through the first pump P1 and the second drive current Ip2 passed through the second pump P2 are equal to or less than a specified current value predetermined for the specific pump. Furthermore, a series of switching controls is repeatedly executed while the pump device 20 is in operation. Therefore, the drive current flowing through the specific pump is maintained at or less than the specified current value.

[0044] As described above, the fluctuation characteristics of the impedance values ​​of the pumps with respect to the environmental temperature vary from pump to pump, and therefore, the magnitude relationship of the impedance values ​​of the pumps may change with changes in the environmental temperature.

[0045] For example, suppose that the drive unit 50 controls only the first pump P1 so that the first drive current Ip1 is equal to the rated current. In this case, if the impedance value of the second pump P2 becomes smaller than the impedance value of the first pump P1, a current larger than the rated current expected to flow through the second pump P2 may flow.

[0046] According to the above embodiment, the calculation processing unit 71 of the control device 70 identifies the specific pump with the smallest impedance value in the identification process S11. Then, the calculation processing unit 71 stores the specific pump as the pump to be controlled in the switching process S13. Next, in the drive process S14, the calculation processing unit 71 controls the drive device 50 so that the drive currents applied to the first pump P1 and the second pump P2 are the rated currents. In other words, the specific pump with the smallest impedance value at the time of executing the switching control is designated as the pump to be controlled.

[0047] (1-1) In the first embodiment, the control device 70 controls the drive voltage Vp of the specific pump with the smallest impedance. In other words, the control device 70 controls the specific pump through which the most current flows. This prevents an unexpectedly large current from flowing through the pumps connected in parallel, even if the impedance relationships among the pumps change due to changes in the ambient temperature or the like.

[0048] (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. Each pump having such impedance characteristics is suitable for a configuration that performs switching control.

[0049] (1-3) In the first embodiment, the control device 70 identifies a specific pump based on the impedance values ​​acquired in the acquisition process S10. Because the impedance values ​​of each pump are calculated directly, the accuracy of determining whether the magnitude relationship of the impedance values ​​of each pump has changed can be improved in the comparison process S12.

[0050] <Regarding a Second Embodiment of a Pump Device and a Program for the Pump Device> A second embodiment of a pump device and a program for the pump device will be described below. Note that the overall configuration of the nebulizer 10 in the second embodiment is the same as the overall configuration of the nebulizer 10 in the first embodiment, and therefore, description thereof will be omitted.

[0051] 4, the pump device 120 of the second embodiment differs in that the pump device 120 includes a temperature sensor 180 and that a memory unit 172 of a control device 170 stores first relationship specifying data RD1 and second relationship specifying data RD2. The pump device 120 of the second embodiment also differs in that the control device 170 controls the drive frequencies of the first drive circuit D3 and the second drive circuit D4 of the drive device 150. Other than these points, the configuration is the same as that of the pump device 20 of the first embodiment, and therefore description thereof will be omitted.

[0052] The pump device 120 of the second embodiment includes a temperature sensor 180. The temperature sensor 180 is housed inside the housing 21 of the pump device 120. The temperature sensor 180 detects an ambient temperature Tp, which is the temperature around the first pump P1. As described above, the first pump P1 and the second pump P2 are housed inside the same housing 21. Therefore, the ambient temperature Tp is also the temperature around the second pump P2.

[0053] In the second embodiment, the storage unit 172 of the control device 170 stores first relationship specifying data RD1 and second relationship specifying data RD2. The first relationship specifying data RD1 is data that specifies the relationship between the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the first pump P1. The second relationship specifying data RD2 is data that specifies the relationship between the environmental temperature Tp detected by the temperature sensor 180 and the impedance value of the second pump P2. Each relationship specifying data is, for example, map data in table format, a regression equation obtained by regression analysis, or the like. A method for creating each relationship specifying data will be described later.

[0054] In the second embodiment, the arithmetic processing unit 171 of the control device 170 is capable of controlling the drive frequency of the AC power supplied to the first pump P1 and the second pump P2. Specifically, the arithmetic processing unit 171 of the control device 170 inputs a PWM signal defined by a predetermined first drive frequency f1 to the first drive circuit D3 of the drive device 150. The PWM signal is input to each switching element of the H-bridge circuit included in the first drive circuit D3. As a result, each switching element is switched on and off based on the first drive frequency f1. In other words, the first drive circuit D3 is a so-called separately excited circuit. Therefore, AC power oscillating based on the first drive frequency f1 is output from a pair of output terminals of the first drive circuit D3.

[0055] The arithmetic processing unit 171 of the control device 170 also inputs a PWM signal defined by a predetermined second drive frequency f2 to the second drive circuit D4. This PWM signal is input to each switching element of the H-bridge circuit included in the second drive circuit D4. This causes each switching element to be switched on and off based on the second drive frequency f2. In other words, the second drive circuit D4 is a so-called externally excited circuit. Therefore, AC power oscillating based on the second drive frequency f2 is output from a pair of output terminals of the second drive circuit D4.

[0056] (Regarding the Switching Control of the Second Embodiment) The switching control of the second embodiment differs from the switching control of the first embodiment in that the environmental temperature Tp is acquired in the acquisition process, and the impedance value of each pump is acquired using the first relationship specifying data RD1 and the second relationship specifying data RD2. Therefore, a description of the process similar to that of the first embodiment will be omitted.

[0057] In the second embodiment, the arithmetic processing unit 171 performs an acquisition process when switching control is initiated. In the acquisition process, the arithmetic processing unit 171 acquires the environmental temperature Tp detected by the temperature sensor 180. Next, the arithmetic processing unit 171 inputs the environmental temperature Tp into the first relationship specifying data RD1. As a result, the arithmetic processing unit 171 acquires the impedance value of the first pump P1 corresponding to the environmental temperature Tp. The arithmetic processing unit 171 also inputs the environmental temperature Tp into the second relationship specifying data RD2. As a result, the arithmetic processing unit 171 acquires the impedance value of the second pump P2 corresponding to the environmental temperature Tp. Then, in the identification process of the second embodiment, the impedance value identified based on the respective relationship specifying data is used to identify the specific pump. Note that the subsequent processes in the switching control of the second embodiment are the same as the processes from the comparison process S12 to the drive process S14 in the switching control of the first embodiment.

[0058] (Regarding Feedback Control of Relationship Specifying Data) In the second embodiment, the arithmetic processing unit 171 of the control device 170 is capable of executing feedback control. This feedback control is executed at a predetermined timing while the pump device 20 is in operation. For example, the feedback control is executed several minutes after the pump device 20 starts to be operated. In the feedback control, the arithmetic processing unit 171 of the control device 170 updates the first relationship specifying data RD1 and the second relationship specifying data RD2.

[0059] 5, when the arithmetic processing unit 171 starts feedback control, it performs an update data acquisition process S20. In the update data acquisition process S20, the arithmetic processing unit 171 of the control device 170 calculates the impedance value of the first pump P1 and the impedance value of the second pump P2.

[0060] Specifically, as shown in FIG. 4 , the arithmetic processing unit 171 acquires the drive voltage Vp output by the power conversion circuit 51. The arithmetic processing unit 171 also acquires the first drive current Ip1 input from the first drive circuit D3 to the first pump P1 and the second drive current Ip2 input from the second drive circuit D4 to the second pump P2. The arithmetic processing unit 171 then calculates the impedance value of the first pump P1 by dividing the drive voltage Vp by the first drive current Ip1. The arithmetic processing unit 171 also calculates the impedance value of the second pump P2 by dividing the drive voltage Vp by the second drive current Ip2. Additionally, the arithmetic processing unit 171 acquires the ambient temperature Tp detected by the temperature sensor 180.

[0061] After the update data acquisition process S20, the calculation processing unit 171 performs an update process S21. In the update process S21, the calculation processing unit 171 updates the first relationship specifying 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 was detected. For example, if the first relationship specifying data RD1 is map data, the calculation processing unit 171 updates the impedance value of the first pump P1 with respect to the acquired environmental temperature Tp. If the first relationship specifying data RD1 is a regression equation based on regression analysis, the regression equation is calculated using the acquired environmental temperature Tp and impedance value of the first pump P1.

[0062] Furthermore, in the update process S21, the calculation processing unit 171 updates the second relationship specifying 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 was detected. The specific method for updating the second relationship specifying data RD2 is the same as the method for updating the first relationship specifying data RD1. Through the above feedback control, the calculation processing unit 171 of the control device 170 can update the first relationship specifying data RD1 and the second relationship specifying data RD2.

[0063] (Operation of the Second Embodiment) In the second embodiment, the calculation processing unit 171 of the control device 170 acquires the environmental temperature Tp and acquires the impedance value of each pump using the first relationship specifying data RD1 and the second relationship specifying data RD2. Then, the specific pump is identified based on each impedance value derived from these relationship specifying data.

[0064] (Effects of the Second Embodiment) According to the second embodiment, in addition to the effects (1-1) to (1-3) of the first embodiment, the following effects are achieved.

[0065] (2-1) In the second embodiment, the arithmetic processing unit 171 of the control device 170 acquires each impedance value by inputting the environmental temperature Tp into the first relationship specifying data RD1 and the second relationship specifying data RD2. By using the environmental temperature Tp, which is correlated with the impedance value, the magnitude relationship between the impedance values ​​of each pump can be determined. Meanwhile, the drive voltage Vp and each drive current, which are susceptible to fluctuations due to external noise, are not directly used in calculating the impedance value, thereby preventing misidentification of a specific pump due to external noise, etc.

[0066] (2-2) In the second embodiment, the arithmetic processing unit 171 of the control device 170 can execute feedback control. The fluctuation characteristics of the impedance value relative to the environmental temperature Tp of the pump may change over time depending on the usage conditions, such as the total time the pump has been used. Therefore, even if the characteristics of the pump change due to changes in the pump device 120 over time, the arithmetic processing unit 171 can execute feedback control to more accurately determine the magnitude relationship between the impedance values.

[0067] (2-3) In the above embodiment, the arithmetic processing unit 171 of the control device 170 controls the drive frequency of each pump. That is, the first drive circuit D3 and the second drive circuit D4 are separately excited circuits. This simplifies the configuration of each circuit. Furthermore, since it is not necessary to use the circuit elements required to generate each drive frequency in the case of a separately excited circuit, the pump device 120 can be made smaller.

[0068] <Modifications> The above embodiment and the following modifications can be implemented in combination with each other within the scope of technical compatibility.

[0069] The pump device 20 is not limited to be applied to the nebulizer 10. The technology related to the pump device 20 described above can be applied to any device that uses two or more pumps connected in parallel on a power supply path. For example, the pump device 20 may be a pressure pump, a pMDI (pressurized metered dose inhaler), a blood pressure monitor, etc.

[0070] The specific type of the first pump P1 is not limited to the example in the above embodiment. For example, the first pump P1 is not limited to a pump capable of pumping gas. It is sufficient that the first pump P1 is capable of pumping at least a fluid, and the first pump P1 may be an electric pump capable of pumping a liquid. The same applies to the second pump P2.

[0071] The type and specifications of the first pump P1 and the second pump P2 do not have to be the same as each other. It is sufficient that the first pump P1 and the second pump P2 can be connected in parallel to each other on the power supply path from the drive unit 50.

[0072] The first pump P1 and the second pump P2 do not have to be arranged in series on the gas flow passage. For example, the first pump P1 and the second pump P2 may be arranged in parallel on the gas flow passage.

[0073] The configuration of the drive device 50 is not limited to the example of the above embodiment. For example, the drive device 50 may have only one drive circuit. In this case, the first pump P1 and the second pump P2 may be connected in parallel 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 said to be arranged in parallel on the power supply path.

[0074] The driving device 50 may be, for example, an inverter. In this case, for example, the driving device 50 may convert a DC voltage input from the power supply unit PU into an AC voltage of a predetermined effective value to drive each pump.

[0075] The power conversion circuit 51 is not limited to the example in the above embodiment. For example, the power conversion circuit 51 does not have to be a boost converter. The power conversion circuit 51 may be modified as appropriate depending on the specifications of the pump and the circuit configuration of each drive circuit.

[0076] In the above embodiment, substantially the same drive voltage Vp is applied to the first pump P1 and the second pump P2, but it is sufficient that the drive voltage Vp applied to each drive circuit from the power conversion circuit 51 is the same. That is, for example, if 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 applied to the first pump P1 and the drive voltage Vp applied to the second pump P2 will be different. Even in such a case, it is sufficient that the first pump P1 and the second pump P2 are connected in parallel to each other on the power supply path from the drive device 50.

[0077] The switching control may be performed at least once during a continuous period in which power is supplied to the pump device 20. For example, the drive control may be performed when the environmental temperature Tp falls within a predetermined temperature range. Examples of the range include a temperature above a predetermined temperature, a temperature below a predetermined temperature, etc.

[0078] In the switching control, the comparison process S12 and the switching process S13 do not have to be executed. In this case, the drive process S14 can be executed with the specific pump identified in the identification process S11 as the control target. Note that in this case, information indicating the specific pump to be controlled is not stored in the storage unit 72. Therefore, in this modified example, a predetermined pump can be the control target from the time the pump device 20 starts to be driven until the first switching control is executed.

[0079] The "prescribed current value" in the drive process S14 does not have to be the rated current. It may be a current value smaller than the rated current or greater than the rated current. In the second embodiment, there may be one temperature sensor 180, or an individual temperature sensor 180 may be provided for each pump to detect the environmental temperature Tp of each pump.

[0080] In the switching control, it is not essential to acquire the impedance values ​​of the first pump P1 and the second pump P2. For example, in the identification process S11, the pump with the smallest impedance value may be identified based on relationship definition data that defines the relationship between the ambient temperature Tp and the pump with the smallest impedance value.

[0081] In the acquisition process S10 of the second embodiment, the impedance value of each pump may be acquired based on other parameters in addition to the environmental temperature Tp. In this case, the storage unit 172 of the control device 170 may store relationship definition data that defines the relationship between the impedance value and the environmental temperature Tp and other parameters.

[0082] The timing of executing the feedback control is not limited to the example in the above embodiment. For example, the feedback control may be executed immediately after the pump device 20 starts to operate, or may be executed repeatedly at predetermined control intervals.

[0083] The content of the first relationship specifying data RD1 is not limited to the example described in the above embodiment. For example, the first relationship specifying data RD1 may be a multiple regression equation with the environmental temperature Tp and the drive voltage Vp as explanatory variables. Furthermore, the first relationship specifying data RD1 may be a machine learning model trained to input the environmental temperature Tp and the drive voltage Vp and output the impedance value of the first pump P1. In any case, it is sufficient that a value corresponding to the impedance value of each pump can be acquired in the acquisition process S10.

[0084] <Supplementary Notes> The technical ideas that can be understood from the above-described embodiments and modified examples will be described below. [1] A pump device including a first electric pump capable of pumping a fluid, a second electric pump capable of pumping a fluid, a drive device capable of converting an input voltage and supplying power to the first pump and the second pump, and a control device that controls the drive device, wherein the first pump and the second pump are connected in parallel to each other on a power supply path from the drive device, and the control device is capable of executing an identification process that identifies, as a specific pump, one of the first pump and the second pump having a smallest impedance value, and a drive process that controls the drive device so that drive currents applied to the first pump and the second pump are equal to or less than a specified current value that is predetermined for the specific pump.

[0085] [2] A pump device as described in [1], wherein when the first pump and the second pump start to be driven, the impedance value of the first pump is greater than the impedance value of the second pump, and after a predetermined time has elapsed since the start of driving, the impedance value of the first pump is smaller than the impedance value of the second pump.

[0086] [3] The control device is capable of executing an acquisition process to acquire the impedance value of the first pump and the impedance value of the second pump, and in the identification process, the specific pump is identified based on the impedance value of the first pump and the impedance value of the second pump acquired in the acquisition process. [1] A pump device as described in [2].

[0087] [4] A pump device as described in [3], further comprising a temperature sensor for detecting an ambient temperature around the pump, wherein the control device stores first relationship specification data that specifies the relationship between the ambient temperature and the impedance value of the first pump, and second relationship specification data that specifies the relationship between the ambient temperature and the impedance value of the second pump, and wherein the acquisition process acquires the impedance value of the first pump and the impedance value of the second pump by inputting the ambient temperature detected by the temperature sensor into the first relationship specification data and the second relationship specification data.

[0088] [5] The control device is further capable of executing an update data acquisition process to calculate an impedance value of the first pump based on the driving voltage of the first pump and the driving current of the first pump, and an update process to update the first relationship specification 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. [4] The pump device described in [5].

[0089] [6] The pump device according to [1] or [2], wherein the control device is capable of controlling the drive frequency of the AC power supplied to the first pump and the second pump. [7] A program for a pump device, which is applied to a pump device including a first electric pump capable of pumping a fluid, a second electric pump capable of pumping a fluid, a drive device capable of converting an input voltage and supplying power to the first pump and the second pump, and a control device that controls the drive device, wherein the first pump and the second pump are connected in parallel to each other on a power supply path from the drive device, and which enables the control device to execute an identification process for identifying, as a specific pump, one of the first pump and the second pump having a smallest impedance value, and a drive process for controlling the drive device so that a drive current passed through the first pump and the second pump is equal to or less than a specified current value predetermined for the specific pump.

[0090] DESCRIPTION OF SYMBOLS 10...Nebulizer 20...Pump device 21...Housing P1...First pump P2...Second pump 50...Driver 51...Power conversion circuit D1...First drive circuit D2...Second drive circuit 70...Control device Vp...Drive voltage Ip1...First drive current Ip2...Second drive current 120...Pump device 150...Driver D3...First drive circuit D4...Second drive circuit 170...Control device f1...First drive frequency f2...Second drive frequency RD1...First relationship specifying data RD2...Second relationship specifying data PG...Program 180...Temperature sensor Tp...Environmental temperature

Claims

1. A pump device comprising: a first electric pump capable of pumping a fluid; a second electric pump capable of pumping a fluid; a drive device capable of converting an input voltage and supplying power to the first pump and the second pump; and a control device that controls the drive device, wherein the first pump and the second pump are connected in parallel to each other on a power supply path from the drive device, and the control device is capable of executing an identification process that identifies as a specific pump one of the first pump and the second pump which has a smallest impedance value; and a drive process that controls the drive device so that a drive current passed through the first pump and the second pump is equal to or less than a specified current value predetermined for the specific pump.

2. The pump device according to claim 1, wherein when the first pump and the second pump start to be driven, the impedance value of the first pump is greater than the impedance value of the second pump, and after a predetermined time has elapsed from the start of driving, the impedance value of the first pump becomes smaller than the impedance value of the second pump.

3. The pump device according to claim 1 or claim 2, wherein the control device is capable of executing an acquisition process to acquire an impedance value of the first pump and an impedance value of the second pump, and in the identification process, the specific pump is identified based on the impedance value of the first pump and the impedance value of the second pump acquired in the acquisition process.

4. A pump device as described in claim 3, further comprising a temperature sensor for detecting an environmental temperature surrounding the pump, wherein the control device stores first relationship specification data that specifies the relationship between the environmental temperature and the impedance value of the first pump, and second relationship specification data that specifies the relationship between the environmental temperature and the impedance value of the second pump, and wherein in the acquisition process, the environmental temperature detected by the temperature sensor is input into the first relationship specification data and the second relationship specification data to acquire the impedance value of the first pump and the impedance value of the second pump.

5. The pump device according to claim 4, wherein the control device is further capable of executing: an update data acquisition process for calculating an impedance value of the first pump based on the drive voltage of the first pump and the drive current of the first pump; and an update process for updating the first relationship definition 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.

6. The pump device according to any one of claims 1 to 5, wherein the control device is capable of controlling a drive frequency of AC power supplied to the first pump and the second pump.

7. A program for a pump device comprising: a first electric pump capable of pumping a fluid; a second electric pump capable of pumping a fluid; a drive device capable of converting an input voltage and supplying power to the first pump and the second pump; and a control device for controlling the drive device, wherein the first pump and the second pump are connected in parallel to each other on a power supply path from the drive device, and the program enables the control device to execute an identification process for identifying as a specific pump one of the first pump and the second pump which has a smallest impedance value; and a drive process for controlling the drive device so that a drive current passed through the first pump and the second pump is equal to or less than a specified current value predetermined for the specific pump.

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