Fluid pumping system, power conversion system, power conversion apparatus, and fluid pumping method

Abstract

To provide a fluid pumping system effective for reducing the frequency of maintenance.SOLUTION: A fluid pumping system 1 comprises: multiple pumping devices 10 for pumping a fluid; a deterioration level estimation unit 115 to estimate a deterioration level of one of the pumping devices 10 based on information about a driving force of the one pumping device 10; a selection unit 215 to select at least one pumping device 10 from the multiple pumping devices 10 based on the deterioration levels estimated by the deterioration level estimation unit 115; and a pumping control unit 216 to cause the pumping device 10 selected by the selection unit 215 to pump the fluid.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a fluid pumping system, a power conversion system, a power conversion device, and a fluid pumping method. [Background technology]

[0002] Patent document 1 discloses a method for operating a variable speed water supply pump, which includes adding a second pump when the operating speed of a first pump continues to exceed the maximum allowable operating speed for a predetermined period of time or more, and stopping the operation of the second pump when the second pump's discharge water volume remains low for a predetermined period of time or more. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-126144 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a fluid pumping system that is effective in reducing the frequency of maintenance. [Means for solving the problem]

[0005] A fluid pumping system according to one aspect of the present disclosure includes a plurality of pumping devices for pumping fluid, a deterioration level estimation unit that estimates the deterioration level of one of the plurality of pumping devices based on information regarding the driving force of that one of the plurality of pumping devices, a selection unit that selects at least one pumping device from the plurality of pumping devices based on the deterioration level estimated by the deterioration level estimation unit, and a pumping control unit that causes the fluid to be pumped by the pumping device selected by the selection unit.

[0006] A power conversion system according to another aspect of the present disclosure includes a plurality of power conversion units that output drive currents to a plurality of electrically driven pumping devices, respectively; a deterioration level estimation unit that estimates the deterioration level of the pumping device based on the drive current output by one of the plurality of power conversion units to the pumping device; a selection unit that selects at least one pumping device from the plurality of pumping devices based on the deterioration level estimated by the deterioration level estimation unit; and a pumping control unit that outputs a drive current from the power conversion units to the pumping device so as to pump a fluid by the at least one pumping device selected by the selection unit.

[0007] A power conversion device according to yet another aspect of the present disclosure includes a power conversion unit that outputs current to an electric motor of an electrically driven mechanical device, a deterioration level estimation unit that estimates the deterioration level of the mechanical device based on the current output by the power conversion unit, and a control unit that causes the power conversion unit to output a drive current to the electric motor to operate the mechanical device when a mechanical device is selected from a plurality of mechanical devices based on the deterioration level estimated by the deterioration level estimation unit.

[0008] A fluid pumping method according to yet another aspect of the present disclosure includes estimating a deterioration level of one of a plurality of pumping devices based on information regarding the driving force of the one of the plurality of pumping devices, selecting at least one pumping device from the plurality of pumping devices based on the estimated deterioration level, and pumping fluid using the selected at least one pumping device. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a fluid pumping system that is effective in reducing the frequency of maintenance. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating a general configuration of a fluid pumping system; [Figure 2] FIG. 2 is a block diagram illustrating a functional configuration of the power conversion system. [Figure 3] FIG. 2 is a block diagram illustrating a hardware configuration of the power conversion system. [Figure 4] FIG. 10 is a schematic diagram showing a modified example of the fluid pumping system. [Figure 5] FIG. 10 is a schematic diagram showing another modified example of the fluid pumping system. [Figure 6] 10 is a flowchart illustrating a control procedure for a plurality of pumping devices. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the description, the same elements or elements having the same functions are denoted by the same reference numerals, and redundant description will be omitted.

[0012] [Fluid pumping system] 1 is a fluid pumping system for increasing the pressure in a water supply pipeline to a water consumer facility such as a faucet or a shower head. The fluid pumping system 1 includes a plurality of electrically operated pumping devices 10, a plurality of check valves 40, a pressure sensor 30, and a power conversion system 20.

[0013] The pumping device 10 (electrically driven mechanical device) pumps water (fluid) using electricity. For example, the pumping device 10 has a pump 11 and a motor 12. The pump 11 has a suction port 11a connected to a primary water supply pipe 91 and a discharge port 11b connected to a secondary water supply pipe 92. The "primary side" refers to the upstream side of the fluid pumping system 1, and the "secondary side" refers to the downstream side of the fluid pumping system 1. The pump 11 incorporates a rotary pumping body such as an impeller or a reciprocating pumping body such as a diaphragm, and pumps water from the suction port 11a to the discharge port 11b by the rotation of the rotary pumping body or the reciprocating movement of the reciprocating pumping body. This causes water to be pumped from the primary water supply pipe 91 to the secondary water supply pipe 92.

[0014] The motor 12 (electric motor) converts electric power into motive power to drive the pump 11. For example, the motor 12 is a synchronous motor or an induction motor that converts AC power into rotational torque. The object to be pumped by the pumping device 10 may be a liquid other than water. Furthermore, the object to be pumped by the pumping device 10 is not necessarily limited to a liquid. For example, the pumping device 10 may have an air blower (e.g., a fan or blower) that pumps gas instead of the pump 11 for pumping liquid. Although two pumping devices 10 are shown in FIG. 1 for convenience, the number of pumping devices 10 is not limited to this. The fluid pumping system 1 may include three or more pumping devices 10.

[0015] The plurality of check valves 40 are respectively interposed between the plurality of suction ports 11a and the secondary water supply pipe 92, and prevent backflow of water from the secondary water supply pipe 92 to the primary water supply pipe 91. The pressure sensor 30 detects the secondary pressure of the fluid pumping system 1. For example, the pressure sensor 30 is connected to the secondary water supply pipe 92 downstream of the plurality of check valves 40.

[0016] The power conversion system 20 causes at least one of the multiple pumping devices 10 to pump water from the primary water supply pipe 91 side to the secondary water supply pipe 92 side in response to a decrease in pressure detected by the pressure sensor 30. The power conversion system 20 is configured to estimate the deterioration level of one of the multiple pumping devices 10 based on information about the driving force of that one of the multiple pumping devices 10, select at least one pumping device 10 from the multiple pumping devices 10 based on the estimated deterioration level, and pump water using the selected at least one pumping device 10.

[0017] For example, the power conversion system 20 includes a plurality of power conversion devices 100 and a controller 200. The plurality of power conversion devices 100 convert power from a power source (for example, a power system or a battery) into driving power (for example, AC power) and supply it to the plurality of pumping devices 10, respectively. In the following description of each power conversion device 100, the pumping device 10 to which power is supplied by the power conversion device 100 will be referred to as the "corresponding pumping device 10."

[0018] The power conversion device 100 is configured to, when a corresponding pumping device 10 is selected from a plurality of pumping devices 10 based on the deterioration level of at least one pumping device 10, output a driving current to the motor 12 of the corresponding pumping device 10 to operate the corresponding pumping device 10, and estimate the deterioration level of the corresponding pumping device 10 based on information regarding the driving force of the corresponding pumping device 10 (e.g., the driving force applied by the motor 12 to the pump 11).

[0019] The controller 200 selects at least one pumping device 10 from the plurality of pumping devices 10 in response to a decrease in pressure detected by the pressure sensor 30, and causes the power conversion device 100 corresponding to the at least one pumping device 10 to output a drive current to the motor 12 so that the selected at least one pumping device 10 pumps water. The controller 200 selects the at least one pumping device 10 from the plurality of pumping devices 10 based on the deterioration level estimated by the at least one power conversion device 100.

[0020] 2 is a block diagram illustrating an example of the functional configuration of the power conversion system 20. The power conversion device 100 has, as functional components (hereinafter referred to as "functional modules"), a power conversion unit 113, a speed control unit 111, a current control unit 112, a current detection unit 114, a deterioration level estimation unit 115, a pumping control unit 116, a force data acquisition unit 117, and a force data storage unit 118.

[0021] The power conversion unit 113 outputs drive power to the motor 12. For example, the power conversion unit 113 outputs to the motor 12 an AC voltage with a voltage amplitude according to a voltage command and a frequency according to the operating speed of the motor 12. For example, the power conversion unit 113 generates the AC voltage using a PWM (Pulse Width Modulation) method. The power conversion unit 113 may be an inverter that converts DC power from a DC bus into AC power to generate drive power, or may be a matrix converter that performs bidirectional power conversion between AC power on the AC power supply side and AC power on the motor 12 side.

[0022] The speed control unit 111 outputs an AC voltage to the motor 12 so that the operating speed of the motor 12 follows the target speed. For example, the speed control unit 111 calculates a current command (torque command) for reducing the deviation between the target speed and the operating speed of the motor 12.

[0023] The current control unit 112 calculates a voltage command for reducing the deviation between the current command calculated by the speed control unit 111 and the drive current being output to the motor 12, and outputs the voltage command to the power conversion unit 113. As a result, the power conversion unit 113 outputs to the motor 12 an AC voltage that causes the operating speed of the motor 12 to follow the target speed.

[0024] The current detection unit 114 detects the drive current output from the power conversion unit 113 to the motor 12 and feeds it back to the current control unit 112. The speed control unit 111, the current control unit 112, the power conversion unit 113, and the current detection unit 114 repeat the above-mentioned processing at a predetermined control period.

[0025] The force data acquisition unit 117 acquires information regarding the driving force of the corresponding pumping device 10 (hereinafter referred to as "force data") for each control cycle. The information regarding the driving force (hereinafter referred to as "force data") may be any information as long as it correlates with the driving force to such an extent that the magnitude of the driving force can be determined based on the information. For example, the magnitude of the driving current correlates (substantially proportional) with the magnitude of the driving force, so the magnitude of the driving current corresponds to force data. Therefore, the force data acquisition unit 117 acquires, as an example, the magnitude of the driving current detected by the current detection unit 114 as force data. Note that the force data acquisition unit 117 may also acquire the magnitude of the current command calculated by the speed control unit 111 as force data. Furthermore, if the pumping device 10 has a driving force sensor (e.g., a torque sensor), the force data acquisition unit 117 may acquire the detected value of the torque sensor as force data. The force data storage unit 118 stores the force data acquired by the force data acquisition unit 117 in chronological order.

[0026] The deterioration level estimation unit 115 estimates the deterioration level of the corresponding pumping device 10 based on the force data. As an example of estimating the deterioration level, the deterioration level estimation unit 115 calculates an amplitude index value corresponding to the amplitude of the vibration component of the force data. Here, "correspondence" refers to a correlation in which the amplitude index value increases or decreases as the amplitude increases or decreases. The amplitude index value may be any value as long as it "corresponds" to the amplitude.

[0027] In the pumping device 10, the amplitude of the vibration component of the force data tends to increase as the deterioration level of the power transmission system from the motor 12 to the pump 11 increases. Therefore, calculating the amplitude index value corresponds to estimating the deterioration level of the pumping device 10. A specific example of the deterioration of the power transmission system is deterioration of the bearings of the torque transmission shaft.

[0028] For example, the deterioration level estimation unit 115 derives the amplitude of the vibration component of the force data as an amplitude index value based on multiple pieces of force data acquired during a predetermined period from the time the force data was acquired to the time the data was acquired. The amplitude may be the width from the negative peak to the positive peak, or half the width from the negative peak to the positive peak. The vibration component is a vibration component during steady operation of the pumping device 10. Steady operation refers to an operating state in which the pump 11 is filled with water and the driving speed of the pump 11 substantially matches the target speed. Substantially matching means that the difference between the driving speed and the target speed is within a negligible error range. The deterioration level estimation unit 115 may calculate the difference between the maximum and minimum values ​​of the force data within a predetermined period as the amplitude, or may calculate the amplitude using a fast Fourier transform (FFT) or the like. The deterioration level estimation unit 115 may calculate the amplitude of a predetermined frequency component using an FFT, or may calculate the average or maximum amplitude of frequency components in a predetermined band.

[0029] The deterioration level estimation unit 115 may calculate, as the amplitude index value, a difference between the force data and a trend value of the force data based on past force data acquired during a predetermined period from before the acquisition of the force data to the acquisition time. For example, the deterioration level estimation unit 115 calculates a trend value for the latest force data by removing DC components from the past force data as necessary and further applying low-pass filtering to the latest force data.

[0030] A specific example of low-pass filtering is finite impulse response filtering. When first-order finite impulse response filtering is used, the trend value is derived by the following equation: Y=A·X[k]+(1-A)·X[k-1]···(1) Y: Trend value X[k]: Latest force data X[k-1]: Previously acquired force data A: Filter coefficient

[0031] When using second-order filtering of the finite impulse response type, the trend value is derived by the following equation: Y=A·X[k]+B·X[k-1]+(1-AB)·X[k-2]···(2) Y: Trend value X[k]: Latest force data X[k-1]: Previously acquired force data X[k-2]: The force data acquired two times before A, B: filter coefficients

[0032] Note that the deterioration level estimation unit 115 does not necessarily need to use the latest force data to calculate the trend value, and may calculate the trend value based only on past force data. For example, the above X[k] may be force data acquired several times (for example, one) before the latest.

[0033] When a corresponding pumping device 10 is selected from the plurality of pumping devices 10 based on the deterioration level estimated by the deterioration level estimation unit 115, the pumping control unit 116 causes the power conversion unit 113 to output a drive current to the motor 12 so as to operate the corresponding pumping device 10. For example, when the corresponding pumping device 10 is selected, the pumping control unit 116 causes the speed control unit 111 to start control (control for making the operating speed of the motor 12 follow a target speed).

[0034] The controller 200 has, as functional modules, a deterioration level information acquisition unit 211, a deterioration level information storage unit 212, an operation history storage unit 213, a pressure information acquisition unit 214, a selection unit 215, and a pumping control unit 216. The deterioration level information acquisition unit 211 acquires the deterioration level estimation results obtained by the deterioration level estimation unit 115 of each power conversion device 100. The deterioration level information storage unit 212 stores the deterioration level estimation results obtained by the deterioration level information acquisition unit 211 for each power conversion device 100. The operation history storage unit 213 stores operation history information of each pumping device 10. The operation history information includes, for example, the start time and stop time of pumping water by the pumping device 10.

[0035] The pressure information acquisition unit 214 acquires information on the secondary side pressure of the multiple pumping devices 10 (for example, a value detected by the pressure sensor 30). The selection unit 215 selects at least one pumping device 10 from the multiple pumping devices 10 in response to the secondary side pressure falling below a predetermined lower limit value (hereinafter referred to as the "pressure lower limit value"). Hereinafter, the pumping device 10 selected by the selection unit 215 is referred to as the "pumping device 10 under normal operation."

[0036] The selection unit 215 selects a pumping device 10 to be subjected to normal operation based on the deterioration level stored in the deterioration level information storage unit 212. For example, the selection unit 215 selects a pumping device 10 to be subjected to normal operation so that the operating period of a pumping device 10 with a high deterioration level is shorter than the operating period of a pumping device 10 with a low deterioration level. As an example, the selection unit 215 selects the pumping device 10 with the lowest deterioration level from the plurality of pumping devices 10.

[0037] The selection unit 215 may select the pumping device 10 to be operated normally based on preset selection criteria and the deterioration level stored in the deterioration level information storage unit 212. For example, the selection unit 215 may select the pumping device 10 to be operated normally based on a first selection criterion based on the deterioration level and a second selection criterion that is preset separately from the first selection criterion. As an example, the first selection criterion is set so as to preferentially select a pumping device 10 with a low deterioration level over a pumping device 10 with a high deterioration level.

[0038] The second selection criterion is set so as to preferentially select a pumping device 10 with a shorter cumulative operating period over a pumping device 10 with a longer cumulative operating period. The cumulative operating period generally correlates with the cumulative number of operations. Therefore, selecting a pumping device 10 with a shorter cumulative operating period over a pumping device 10 with a longer cumulative operating period includes selecting a pumping device 10 with a smaller cumulative number of operations over a pumping device 10 with a larger cumulative number of operations.

[0039] For example, the selection unit 215 derives the priority of each pumping device 10 based on both the first selection criterion and the second selection criterion, and selects the pumping device 10 with the highest priority. For example, the selection unit 215 derives the priority based on a function or table or the like that is defined so that when there is no difference in the cumulative operating period, the priority of a pumping device 10 with a low level of deterioration is higher than the priority of a pumping device 10 with a high level of deterioration, and when there is no difference in the deterioration level, the priority of a pumping device 10 with a short cumulative operating period is higher than the priority of a pumping device 10 with a long cumulative operating period.

[0040] The selection unit 215 may select the pumping device 10 to be operated normally based on preset selection criteria, and may select the pumping device 10 to be operated normally based on the deterioration level when the deterioration level of any of the plurality of pumping devices 10 exceeds a predetermined threshold (hereinafter referred to as the "reference switching threshold"). For example, the selection unit 215 may select the pumping device 10 to be operated normally based on the second selection criteria when the maximum deterioration level of the plurality of pumping devices 10 (hereinafter simply referred to as the "maximum deterioration level") is below the reference switching threshold, and may select the pumping device 10 to be operated normally based on the first selection criteria when the maximum deterioration level exceeds the reference switching threshold.

[0041] The selection unit 215 may change the weight of the first selection criterion relative to the second selection criterion as the deterioration level increases. For example, the selection unit 215 may change the weight of the first selection criterion relative to the second selection criterion based on the relationship between multiple levels of criterion switching thresholds and the maximum deterioration level. As an example, the selection unit 215 may select the pumping device 10 to be operated normally based only on the second selection criterion when the maximum deterioration level is below the minimum criterion switching threshold, increase the weight of the first selection criterion relative to the second selection criterion each time the maximum deterioration level exceeds the criterion switching threshold, and select the pumping device 10 to be operated normally based only on the first selection criterion when the maximum deterioration level exceeds the maximum criterion switching threshold. The selection unit 215 cancels the selection of the pumping device 10 to be operated normally when the secondary side pressure exceeds a predetermined upper limit value (hereinafter referred to as the "pressure upper limit value").

[0042] When the pumping device 10 to be operated normally is selected, the pumping control unit 216 outputs a drive start command to the power conversion device 100 corresponding to the pumping device 10 to be operated normally. In response to this, the pumping control unit 116 of the power conversion device 100 starts pumping water by the pumping device 10 to be operated normally. That is, the pumping control unit 216 causes the pumping device 10 selected by the selection unit 215 to pump water.

[0043] When the selection of the pumping device 10 that is the target of normal operation is canceled, the pumping control unit 216 outputs a drive stop command to the power conversion device 100 that corresponds to the pumping device 10 that is the target of normal operation. In response to this, the pumping control unit 116 of the power conversion device 100 stops the pumping of water by the pumping device 10 that is the target of normal operation.

[0044] The controller 200 may be configured to, when the secondary pressure (e.g., the value detected by the pressure sensor 30) of the pumping device 10 that is normally operated is insufficient, also pump water to at least one pumping device 10 that is not selected by the selection unit 215. For example, the controller 200 further includes an additional selection unit 217.

[0045] When the secondary side pressure of the pumping device 10 to be operated normally is insufficient, the additional selection unit 217 selects at least one pumping device 10 not selected by the selection unit 215 from the multiple pumping devices 10. Hereinafter, the pumping device 10 selected by the additional selection unit 217 is referred to as the "pumping device 10 to be operated additionally." For example, when the detection value by the pressure sensor 30 is below a predetermined threshold (hereinafter referred to as the "additional threshold") even though the pumping device 10 to be operated normally is pumping water, the additional selection unit 217 selects the pumping device 10 to be operated additionally. The additional threshold may be any value as long as it is equal to or greater than the above-mentioned lower pressure limit and less than the above-mentioned upper pressure limit. When the secondary side pressure exceeds the above-mentioned upper pressure limit, the additional selection unit 217 cancels the selection of the pumping device 10 to be operated additionally.

[0046] When the additional selection unit 217 selects the pumping device 10 to be additionally operated, the pumping control unit 216 outputs a drive start command to the power conversion device 100 corresponding to the pumping device 10 to be additionally operated. In response to this, the pumping control unit 116 of the power conversion device 100 starts pumping water by the pumping device 10 to be additionally operated. That is, the pumping control unit 216 also pumps water to the pumping device 10 to be additionally operated during the period when the pumping control unit 116 for normal operation is pumping water by the pumping device 10 to be normally operated. When the selection of the pumping device 10 to be additionally operated is canceled, the pumping control unit 216 outputs a drive stop command to the power conversion device 100 corresponding to the pumping device 10 to be additionally operated. In response to this, the pumping control unit 116 of the power conversion device 100 stops pumping water by the pumping device 10 to be additionally operated.

[0047] The additional selection unit 217 may be configured to select a pumping device 10 having a higher deterioration level than the pumping device 10 that is the target of normal operation. For example, when the selection unit 215 does not select a pumping device 10 whose deterioration level exceeds a predetermined threshold, the additional selection unit 217 may also be configured to select a pumping device 10 whose deterioration level exceeds the threshold. For example, the additional selection unit 217 may also be configured to select a pumping device 10 whose deterioration level exceeds the maximum reference switching threshold.

[0048] The controller 200 may be further configured to notify a user of the deterioration level of at least one pumping device 10. For example, the controller 200 further includes a deterioration notification unit 218. The deterioration notification unit 218 notifies a user, via a display device, that the deterioration level of at least one pumping device 10 has exceeded a predetermined threshold (hereinafter referred to as an "alert threshold"). In other words, the deterioration notification unit 218 notifies a user, via a display device, that the maximum value of the deterioration level has exceeded the alert threshold. Specific examples of the display device include an LCD monitor or an alarm lamp. The alert threshold may be higher than the reference switching threshold described above.

[0049] The deterioration notification unit 218 may be configured to notify the user of changes in the relationship between multiple alert thresholds and the maximum value of the deterioration level. For example, the deterioration notification unit 218 may be configured to notify the user of an increase in the deterioration level every time the increasing deterioration level exceeds the alert threshold. The increase in the deterioration level can be notified by a change in the content displayed on the LCD monitor, a change in the color of an alarm lamp, or the like.

[0050] The deterioration notification unit may be configured to further notify which of the pumping devices 10 has exceeded the deterioration level at which alert threshold. The notification of which of the pumping devices 10 has exceeded the deterioration level at which alert threshold can be made by, for example, displaying on a liquid crystal monitor the identification information of the pumping device 10 that has exceeded the alert threshold. The notification of which of the pumping devices 10 has exceeded the deterioration level at which alert threshold can also be made by checking whether any of the alarm lamps provided for each pumping device 10 is lit.

[0051] 3 is a block diagram illustrating a hardware configuration of the power conversion system 20. As shown in FIG.

[0052] The switching circuit 120 operates in accordance with commands from the control circuit 140 (for example, electrical signals from the input / output port 144) and functions as the power conversion unit 113. For example, the switching circuit 120 outputs the drive power to the motor 12 by switching on and off a plurality of switching elements in accordance with electrical signals (for example, gate signals) from the input / output port 144. The switching elements are, for example, power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors). The current sensor 130 operates in accordance with commands from the control circuit 140 (for example, electrical signals from the input / output port 144) and functions as the current detection unit 114 described above. The current sensor 130 detects the output current from the switching circuit 120 to the motor 12.

[0053] The control circuit 140 includes one or more processors 141, a memory 142, a storage 143, and an input / output port 144. The storage 143 has a computer-readable storage medium, such as a non-volatile semiconductor memory. The storage 143 stores a program that causes the power conversion device 100 to output a drive current to the motor 12 of the corresponding pumping device 10 to operate the corresponding pumping device 10 when the corresponding pumping device 10 is selected from the plurality of pumping devices 10 based on the deterioration level of the corresponding pumping device 10, and to estimate the deterioration level of the corresponding pumping device 10 based on information related to the drive force of the corresponding pumping device 10 (e.g., the drive force applied by the motor 12 to the pump 11). For example, the storage 143 stores a program for configuring the functional modules of the power conversion device 10 described above.

[0054] The memory 142 temporarily stores the programs loaded from the storage medium of the storage 143 and the results of calculations by the processor 141. The processor 141 executes the programs in cooperation with the memory 142 to configure each functional module of the power conversion device 100. The input / output port 144 has a terminal block for the input power supply, and also inputs and outputs electrical signals between the switching circuit 120, the current sensor 130, and the controller 200 in accordance with instructions from the processor 141.

[0055] The controller 200 includes a circuit 220. The circuit 220 includes one or more processors 221, a memory 222, a storage 223, a display device 224, and an input / output port 225. The storage 223 includes a computer-readable storage medium, such as a non-volatile semiconductor memory. The storage 223 stores a program that causes the controller 200 to execute the following operations: select at least one pumping device 10 from the multiple pumping devices 10 based on the deterioration level estimated by at least one power conversion device 100; and output a drive current from the power conversion device 100 corresponding to the at least one selected pumping device 10 to the motor 12 so as to pump water through the at least one selected pumping device 10. For example, the storage 223 stores a program for configuring the functional modules of the controller 200 described above.

[0056] The storage 143 of the power conversion device 100 and the storage 223 of the controller 200 correspond to the storage of the power conversion system 20, and this storage stores a program that causes the power conversion system 20 to estimate the deterioration level of one of the multiple pumping devices 10 based on information regarding the driving force of that one of the multiple pumping devices 10, select at least one pumping device 10 from the multiple pumping devices 10 based on the estimated deterioration level, and pump water using the selected at least one pumping device 10.

[0057] The memory 222 temporarily stores programs loaded from the storage 223 and calculation results by the processor 221. The processor 221 executes the above applications in cooperation with the memory 222. The display device 224 includes, for example, an LCD monitor, an alarm lamp, etc., and is used to display information to the user. The input / output port 225 inputs and outputs electrical signals between the pressure sensor 30 and the power conversion device 100 in accordance with commands from the processor 221.

[0058] The control circuit 140 and the circuit 220 are not necessarily limited to those that configure each function by a program. For example, the control circuit 140 and the circuit 220 may configure at least some of their functions by dedicated logic circuits or ASICs (Application Specific Integrated Circuits) that integrate such circuits.

[0059] It should be noted that the configuration of the power conversion system 20 shown above is merely an example and can be modified as appropriate. For example, in the above example, one controller 200 is provided for a plurality of power conversion devices 100, but this is not limiting, and a plurality of controllers 200 may be provided for a plurality of power conversion devices 100 (see FIG. 4). In this case, it is possible to configure the functional module of the controller 200 described above using at least one of the plurality of controllers 200. Furthermore, the functional module of the controller 200 may be configured using any of the plurality of power conversion devices 100. In this case, it is also possible to omit the controller 200 (see FIG. 5).

[0060] [Fluid pumping method] Next, as an example of a fluid pumping method, a control procedure for the multiple pumping devices 10 executed by the power conversion system 20 will be illustrated. This control procedure includes estimating the deterioration level of one of the multiple pumping devices 10 based on information about the driving force of that one of the multiple pumping devices 10, selecting at least one pumping device 10 from the multiple pumping devices 10 based on the estimated deterioration level, and pumping water using the selected at least one pumping device 10.

[0061] 6 is a flowchart illustrating a control procedure for a plurality of pumping devices 10. As shown in FIG. 6, the power conversion system 20 first executes step S01. In step S01, the pressure information acquisition unit 214 acquires a value detected by the pressure sensor 30 as information on the secondary pressure, and the selection unit 215 checks whether the detected value is below the pressure lower limit. If it is determined that the value detected by the pressure sensor 30 is not below the pressure lower limit, the power conversion system 20 executes step S01 again. Thereafter, step S01 is repeated until the value detected by the pressure sensor 30 falls below the pressure lower limit.

[0062] If it is determined that the detection value by the pressure sensor 30 is below the pressure lower limit, the power conversion system 20 executes steps S02, S03, S04, and S05. In step S02, the selection unit 215 selects the pumping device 10 that is the target of normal operation based on the deterioration level stored in the deterioration level information storage unit 212. In step S03, the pumping control unit 216 outputs a drive start command to the power conversion device 100 that corresponds to the pumping device 10 that is the target of normal operation (hereinafter referred to as the "power conversion device 100 for normal operation"). In response to this, the pumping control unit 116 of the power conversion device 100 starts pumping water by the pumping device 10 that is the target of normal operation. In step S04, the force data acquisition unit 117 of the power conversion device 100 for normal operation starts acquiring force data.

[0063] In step S05, the pressure information acquisition unit 214 acquires the value detected by the pressure sensor 30 as information on the secondary pressure, and the selection unit 215 checks whether the detected value exceeds the upper pressure limit. If it is determined in step S05 that the detected value does not exceed the upper pressure limit, the power conversion system 20 executes step S06. In step S06, the additional selection unit 217 checks whether the value detected by the pressure sensor 30 is below the additional threshold.

[0064] If it is determined in step S06 that the detected value is below the additional threshold, the power conversion system 20 executes steps S07, S08, and S09. In step S07, the additional selection unit 217 selects the pumping-feed device 10 to be the additional operation target from the multiple pumping-feed devices 10. In step S08, the pumping control unit 216 outputs a drive start command to the power conversion device 100 corresponding to the pumping-feed device 10 to be the additional operation target (hereinafter referred to as the "power conversion device 100 for additional operation"). In response to this, the pumping control unit 116 of the power conversion device 100 starts pumping water by the pumping-feed device 10 to be the additional operation target. In step S09, the force data acquisition unit 117 of the power conversion device 100 for additional operation starts acquiring force data. Thereafter, the power conversion system 20 returns the process to step S05.

[0065] If it is determined in step S06 that the detected value is not below the additional threshold, the power conversion system 20 returns the process to step S05 without executing steps S07, S08, and S09. After that, the pumping device 10 that is the normal operation target continues to pump water, and the pumping device 10 that is the additional operation target also continues to pump water as needed, until the detected value by the pressure sensor 30 exceeds the upper pressure limit.

[0066] If it is determined in step S05 that the detected value exceeds the upper pressure limit, the power conversion system 20 executes step S11. In step S11, the selection unit 215 cancels the selection of the pumping device 10 that is the target of normal operation. In response to this, the pumping control unit 116 of the power conversion device 100 for normal operation stops the pumping of water by the pumping device 10 that is the target of normal operation. If the pumping device 10 that is the target of additional operation has been selected, the additional selection unit 217 further cancels the selection of the pumping device 10 that is the target of additional operation. In response to this, the pumping control unit 116 of the power conversion device 100 for additional operation stops the pumping of water by the pumping device 10 that is the target of additional operation.

[0067] Next, the power conversion system 20 executes steps S12 and S13. In step S12, the deterioration level estimation unit 115 of the power conversion device 100 for normal operation estimates the deterioration level of the pumping device 10 that is the target of normal operation based on the force data stored in the force data storage unit 118 of the power conversion device 100. When the pumping device 10 that is the target of additional operation is selected, the deterioration level estimation unit 115 of the power conversion device 100 for additional operation further estimates the deterioration level of the pumping device 10 that is the target of additional operation based on the force data stored in the force data storage unit 118 of the power conversion device 100 for normal operation. In step S13, the deterioration level information acquisition unit 211 acquires the estimation results of the deterioration levels by the deterioration level estimation units 115 of the power conversion devices 100 for normal operation and the power conversion device 100 for additional operation, and stores them in the deterioration level information storage unit 212. The power conversion system 20 repeats the above processing.

[0068] In the above-described procedure, the deterioration level is estimated once after the operation of the pumping device 10 is stopped, but the timing for estimating the deterioration level is not necessarily limited to this. For example, the deterioration level may be repeatedly estimated during operation. In this case, the pumping device 10 to be operated may be switched to the operating state in response to an increase in the deterioration level.

[0069] [Effects of this embodiment] As described above, the fluid pumping system 1 comprises a plurality of pumping devices 10 for pumping water, a deterioration level estimation unit 115 that estimates the deterioration level of one of the plurality of pumping devices 10 based on information regarding the driving force of that one of the plurality of pumping devices 10, a selection unit 215 that selects at least one pumping device 10 from the plurality of pumping devices 10 based on the deterioration level estimated by the deterioration level estimation unit 115, and a pumping control unit 216 that pumps water using the pumping device 10 selected by the selection unit 215.

[0070] According to this fluid pumping system 1, the selection criteria are automatically changed based on the deterioration level, making it possible to prioritize operation of pumping devices 10 with low deterioration levels. This makes it possible to suppress the progression of deterioration of pumping devices 10 with high deterioration levels. This is therefore effective in reducing the frequency of maintenance. Furthermore, suppressing the progression of deterioration of pumping devices 10 with high deterioration levels can also contribute to improved operating efficiency, vibration suppression, noise suppression, etc.

[0071] The selection unit 215 may select at least one pumping device 10 based on preset selection criteria and the deterioration level estimated by the deterioration level estimation unit 115. In this case, when the deterioration of any of the pumping devices 10 is not progressing, it is possible to selectively use a plurality of pumping devices 10 according to desired conditions by setting the selection criteria.

[0072] The selection unit 215 may select at least one pumping device 10 based on a selection criterion set to prioritize pumping devices 10 with shorter cumulative operating periods over pumping devices 10 with longer cumulative operating periods, and on the deterioration level.

[0073] The selection unit 215 may select at least one pumping device 10 based on the selection criteria, and if the deterioration level of any of the multiple pumping devices 10 exceeds a predetermined threshold, may select at least one pumping device 10 based on the deterioration level.

[0074] The selection unit 215 may select at least one pumping device 10 so that the operation period of the pumping device 10 with a high deterioration level is shorter than the operation period of the pumping device 10 with a low deterioration level. In this case, the operation of the pumping device 10 with a low deterioration level can be more reliably prioritized.

[0075] The fluid pumping system 1 further includes an additional selection unit 217 that selects at least one pumping device 10 not selected by the selection unit 215 from the multiple pumping devices 10 when the secondary pressure of the pumping device 10 selected by the selection unit 215 is insufficient. The pumping control unit 216 may also pump water to the pumping device 10 selected by the additional selection unit 217 during the period in which the pumping device 10 selected by the selection unit 215 is pumping water. In this case, by suppressing the progression of deterioration of the pumping device 10 with a high level of deterioration, the period in which the pumping device 10 can be used as an additional operating device can be extended. Therefore, in a configuration that switches between an operation mode that does not use an additional operating device (hereinafter referred to as a "normal operation mode") and an operation mode that uses an additional operating device (hereinafter referred to as a "parallel operation mode"), it is more effective to suppress the progression of deterioration of the pumping device 10 with a high level of deterioration.

[0076] The additional selection unit 217 may select a pumping device 10 having a higher deterioration level than the pumping device 10 selected by the selection unit 215. The operating period of the pumping device 10 to be added to the operation target is shorter than the operating period of the pumping device 10 to be operated. Therefore, by assigning the pumping device 10 having a high deterioration level to the additional operation target, the pumping device 10 can be effectively utilized while suppressing the progress of deterioration of the pumping device 10 having a high deterioration level.

[0077] The selection unit 215 may not select a pumping device 10 whose deterioration level exceeds a predetermined threshold, and the additional selection unit 217 may also select a pumping device 10 whose deterioration level exceeds the threshold. In this case, it is possible to more reliably suppress the progress of deterioration of a pumping device 10 whose deterioration level is high and to more reliably utilize the pumping device 10 as an additional operation target.

[0078] The fluid pumping system 1 may further include a deterioration notification unit 218 that notifies the user that the deterioration level has exceeded a predetermined threshold. In this case, it is possible to more reliably optimize the timing of maintenance.

[0079] The deterioration notification unit 218 may further notify which of the pumping devices 10 has a deterioration level that exceeds a threshold value. In this case, it is effective in improving the efficiency of maintenance work.

[0080] The pumping device 10 is electrically driven, and the deterioration level estimation unit 115 may estimate the deterioration level of the pumping device 10 based on the drive current of the pumping device 10.

[0081] Although the embodiment has been described above, the present invention is not necessarily limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. The application of the power conversion system 20 is not necessarily limited to a fluid pumping system. The power conversion system 20 can be applied to any mechanical system as long as it is a mechanical system that selectively operates multiple mechanical devices. [Explanation of symbols]

[0082] 1...fluid pumping system, 10...pumping device (electric mechanical device), 12...motor (electric motor), 20...power conversion system, 100...power conversion device, 113...power conversion unit, 115...deterioration level estimation unit, 215...selection unit, 216...pumping control unit, 217...additional selection unit, 218...deterioration notification unit.

Claims

1. A plurality of electrically powered pumping devices for pumping fluid; a plurality of power conversion units each outputting a drive current to each of the plurality of pumping devices in response to a current command; a force data acquisition unit that acquires a magnitude of the current command as force data from each of the plurality of power conversion units; a deterioration level estimation unit that estimates a deterioration level of each of the plurality of pumping devices based on a vibration magnitude of the force data; a selection unit that selects at least one pumping device from the plurality of pumping devices based on the deterioration levels of the plurality of pumping devices estimated by the deterioration level estimation unit; a pumping control unit that outputs the drive current from at least one power conversion unit corresponding to the at least one pumping device to the at least one pumping device selected by the selection unit so as to pump a fluid by the at least one pumping device; A fluid pumping system comprising:

2. The fluid pumping system according to claim 1 , wherein the selection unit selects the at least one pumping device based on a preset selection criterion and the deterioration level estimated by the deterioration level estimation unit.

3. 3. The fluid pumping system according to claim 2, wherein the selection unit selects the at least one pumping device based on the deterioration level and the selection criterion that is defined to preferentially select the pumping device with a shorter cumulative operating period over the pumping device with a longer cumulative operating period.

4. The fluid pumping system of claim 2, wherein the selection unit selects the at least one pumping device based on the selection criteria, and when the deterioration level of any of the plurality of pumping devices exceeds a predetermined threshold, selects the at least one pumping device based on the deterioration level.

5. The fluid pumping system according to any one of claims 1 to 4, wherein the selection unit selects the at least one pumping device such that an operating period of the pumping device having a high deterioration level is shorter than an operating period of the pumping device having a low deterioration level.

6. Further, an additional selection unit is provided which selects at least one pumping device not selected by the selection unit from the plurality of pumping devices when the secondary side pressure in the pumping device selected by the selection unit is insufficient, The fluid pumping system according to any one of claims 1 to 5, wherein the pumping control unit also pumps fluid to a pumping device selected by the additional selection unit during a period in which the pumping control unit is pumping fluid to the pumping device selected by the selection unit.

7. The fluid pumping system according to claim 6 , wherein the additional selection unit selects the pumping device having a higher deterioration level than the pumping device selected by the selection unit.

8. The selection unit does not select the pumping device whose deterioration level exceeds a predetermined threshold, The fluid pumping system according to claim 7 , wherein the additional selection unit also selects the pumping device whose deterioration level exceeds the threshold.

9. 9. The fluid pumping system according to claim 1, further comprising a deterioration notification unit that notifies a user that the deterioration level has exceeded a predetermined threshold.

10. The fluid pumping system according to claim 9 , wherein the deterioration notification unit further notifies which of the pumping devices the deterioration level of which has exceeded the threshold value.

11. a plurality of power conversion units each outputting a drive current corresponding to a current command to a plurality of electric pumping devices; a force data acquisition unit that acquires a magnitude of the current command as force data from each of the plurality of power conversion units; a deterioration level estimation unit that estimates a deterioration level of each of the plurality of pumping devices based on a vibration magnitude of the force data; a selection unit that selects at least one pumping device from the plurality of pumping devices based on the deterioration levels of the plurality of pumping devices estimated by the deterioration level estimation unit; and a pumping control unit that outputs the drive current from at least one power conversion unit corresponding to the at least one pumping device to the at least one pumping device selected by the selection unit so as to pump a fluid by the at least one pumping device.

12. A method for producing a pumping device comprising: acquiring, as force data, a magnitude of a current command from each of a plurality of power conversion devices which output drive currents in response to the current commands to a plurality of electric pumping devices; estimating a deterioration level of each of the plurality of pumping devices based on a vibration magnitude of the force data; selecting at least one pumping device from the plurality of pumping devices based on the estimated deterioration levels of each of the plurality of pumping devices; and outputting the drive current from at least one power conversion device corresponding to the at least one pumping device to the at least one pumping device so as to pump fluid by the at least one selected pumping device.

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