Fluid pumping system, power conversion system, power conversion device, 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 Art

[0002] Patent Document 1 discloses an operation method of a variable-speed water supply pump including adding a second pump when the operating speed of a first pump continues at the allowable maximum operating speed for a predetermined time or more, and stopping the operation of the second pump when a state where the discharge water volume of the second pump is small continues for a predetermined time or more.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

Means for Solving the Problems

[0005] A fluid pumping system according to one aspect of the present disclosure includes a plurality of pumping devices for pumping a fluid, a deterioration level estimation unit that estimates a deterioration level of one of the plurality of pumping devices based on information regarding a driving force of any 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 pumps the fluid 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 respectively output drive currents to a plurality of electric pumping devices; a degradation level estimation unit that estimates a degradation level of a pumping device based on a drive current output from any 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 degradation level estimated by the degradation level estimation unit; and a pumping control unit that outputs a drive current from the power conversion unit 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 still another aspect of the present disclosure includes: a power conversion unit that outputs a current to an electric motor of an electric mechanical device; a degradation level estimation unit that estimates a degradation level of the mechanical device based on the current output from the power conversion unit; and a control unit that outputs a drive current from the power conversion unit to the electric motor so as to operate the mechanical device when the mechanical device is selected from a plurality of mechanical devices based on the degradation level estimated by the degradation level estimation unit.

[0008] A fluid pumping method according to still another aspect of the present disclosure includes: estimating a degradation level of one of a plurality of pumping devices based on information regarding a driving force of the one pumping device; selecting at least one pumping device from the plurality of pumping devices based on the estimated degradation level; and pumping a fluid by the selected at least one pumping device.

Advantages of the Invention

[0009] According to the present disclosure, a fluid pumping system effective in reducing maintenance frequency can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

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

[0012] 〔Fluid pumping system〕 The fluid pumping system 1 shown in FIG. 1 is a pumping system for boosting a water supply pipeline to water service equipment such as a faucet or a shower head. The fluid pumping system 1 includes a plurality of electric pumping devices 10, a plurality of check valves 40, a pressure sensor 30, and a power conversion system 20.

[0013] The pumping device 10 (an electric mechanical device) pumps water (fluid) by electric power. For example, the pumping device 10 has a pump 11 and a motor 12. The pump 11 has a suction port 11a connected to the primary side water supply pipe 91 and a discharge port 11b connected to the secondary side water supply pipe 92. "Primary side" means the upstream side of the fluid pumping system 1, and "secondary side" means 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 reciprocation of the reciprocating pumping body. Thereby, water is pumped from the primary side water supply pipe 91 to the secondary side 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. Note that the fluid to be pumped by the pumping device 10 may be a liquid other than water. Also, the fluid to be pumped by the pumping device 10 is not necessarily limited to a liquid. For example, the pumping device 10 may have a blower (e.g., a fan or a blower) that pumps gas instead of the pump 11 for liquid pumping. In FIG. 1, two pumping devices 10 are shown for convenience, but 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-side water supply pipe 92 to prevent the backflow of water from the secondary-side water supply pipe 92 to the primary-side water supply pipe 91. The pressure sensor 30 detects the secondary-side pressure of the fluid pumping system 1. For example, the pressure sensor 30 is connected to the secondary-side water supply pipe 92 downstream of the plurality of check valves 40.

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

[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 the power of a power source (e.g., a power grid or a battery) into driving power (e.g., AC power) and supply it to the plurality of pumping devices 10 respectively. Hereinafter, in the description of each power conversion device 100, the pumping device 10 that is the power supply target of the power conversion device 100 is referred to as the "corresponding pumping device 10".

[0018] When the corresponding pumping device 10 is selected from the plurality of pumping devices 10 based on the degradation level of at least one pumping device 10, the power conversion device 100 outputs a driving current to the motor 12 of the corresponding pumping device 10 so as to operate the corresponding pumping device 10, and estimates the degradation level of the corresponding pumping device 10 based on information regarding the driving force of the corresponding pumping device 10 (for example, the driving force applied by the motor 12 to the pump 11).

[0019] When the pressure detected by the pressure sensor 30 decreases, the controller 200 selects at least one pumping device 10 from the plurality of pumping devices 10, and outputs a driving current to the motor 12 from the power conversion device 100 corresponding to the at least one selected pumping device 10 so as to pump water by the at least one selected pumping device 10. The controller 200 selects the at least one pumping device 10 from the plurality of pumping devices 10 based on the degradation level estimated by at least one power conversion device 100.

[0020] FIG. 2 is a block diagram illustrating a functional configuration of the power conversion system 20. The power conversion device 100 includes, as a functional configuration (hereinafter referred to as a “function module”), a power conversion unit 113, a speed control unit 111, a current control unit 112, a current detection unit 114, a degradation level estimation unit 115, a pumping control unit 116, a force data acquisition unit 117, and a force data holding unit 118.

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

[0022] The speed control unit 111 outputs an alternating voltage from the speed control unit 111 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 it to the power conversion unit 113. As a result, the power conversion unit 113 outputs an alternating voltage that causes the operating speed of the motor 12 to follow the target speed to the motor 12.

[0024] The current detection unit 114 detects the drive current output by 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-described processing at a predetermined control cycle.

[0025] The force data acquisition unit 117 acquires information regarding the driving force of the corresponding pressure feeding 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 grasped based on the information. For example, since the magnitude of the above drive current correlates (is approximately proportional) with the magnitude of the driving force, the magnitude of the drive current corresponds to the force data. Therefore, as an example, the force data acquisition unit 117 acquires the magnitude of the drive current detected by the current detection unit 114 as the force data. Note that the force data acquisition unit 117 may acquire the magnitude of the current command calculated by the speed control unit 111 as the force data. Further, when the pressure feeding device 10 has a sensor for the driving force (for example, a torque sensor), the force data acquisition unit 117 may acquire the detection value of the torque sensor as the force data. The force data holding unit 118 stores the force data acquired by the force data acquisition unit 117 in time series.

[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, "corresponding" means a correlation relationship in which the amplitude index value increases or decreases according to the increase or decrease of the amplitude. The amplitude index value may be any value as long as it "corresponds" to the amplitude.

[0027] In the pumping device 10, as the deterioration level of the power transmission system from the motor 12 to the pump 11 increases, the amplitude of the vibration component of the force data tends to increase. 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 includes 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 the amplitude index value based on a plurality of force data acquired from a predetermined period before the acquisition of the force data to the acquisition time. The amplitude may be the width from the negative peak to the positive peak, or may be half of the width from the negative peak to the positive peak. The vibration component is the vibration component in the steady operation of the pumping device 10. Steady operation means an operating state in which water is filled in the pump 11 and the driving speed of the pump 11 substantially coincides with the target speed. Substantially coincides 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 value and the minimum value of the force data within a predetermined period as the amplitude, or may calculate the amplitude by fast Fourier transform (FFT) or the like. The deterioration level estimation unit 115 may calculate the amplitude of a predetermined frequency component by FFT, or may calculate the average value or the maximum value of the amplitudes in the frequency components of a predetermined band.

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

[0030] As a specific example of the low-pass filtering, filtering by the finite impulse response method can be mentioned. When using the first-order filtering of the finite impulse response method, the trend value is derived by the following formula. Y = A·X[k] + (1 - A)·X[k - 1] ··· (1) Y: Trend value X[k]: Latest force data X[k - 1]: Force data acquired one time before A: Filter coefficient

[0031] When using the second-order filtering of the finite impulse response method, the trend value is derived by the following formula. Y = A·X[k] + B·X[k - 1] + (1 - A - B)·X[k - 2] ··· (2) Y: Trend value X[k]: Latest force data X[k - 1]: Force data acquired one time before X[k - 2]: Force data acquired two times before A, B: Filter coefficients

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

[0033] When the 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 pressure feeding 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 pressure feeding control unit 116 starts the control by the speed control unit 111 (control for causing the operating speed of the motor 12 to follow the target speed).

[0034] The controller 200 includes, 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 pressure feeding control unit 216. The deterioration level information acquisition unit 211 acquires the estimation result of the deterioration level by the deterioration level estimation unit 115 of each power conversion device 100. The deterioration level information storage unit 212 stores the estimation result of the deterioration level acquired by the deterioration level information acquisition unit 211 for each power conversion device 100. The operation history storage unit 213 stores the operation history information of each pumping device 10. The operation history information includes, for example, the water pumping start time and the water pumping stop time by the pumping device 10.

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

[0036] The selection unit 215 selects the pumping device 10 for normal operation based on the deterioration level stored in the deterioration level information storage unit 212. For example, the selection unit 215 selects the pumping device 10 for normal operation 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. 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 for normal operation based on a preset selection criterion and the degradation level stored in the degradation level information storage unit 212. For example, the selection unit 215 may select the pumping device 10 for normal operation based on a first selection criterion based on the degradation level and a second selection criterion preset separately from the first selection criterion. As an example, the first selection criterion is set to preferentially select the pumping device 10 with a lower degradation level over the pumping device 10 with a higher degradation level.

[0038] The second selection criterion is set to preferentially select the pumping device 10 with a shorter cumulative operation period over the pumping device 10 with a longer cumulative operation period. Note that the cumulative operation period generally correlates with the cumulative number of operations. Therefore, preferentially selecting the pumping device 10 with a shorter cumulative operation period over the pumping device 10 with a longer cumulative operation period includes preferentially selecting the pumping device 10 with a smaller cumulative number of operations over the 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, when there is no difference in the cumulative operation period, the priority of the pumping device 10 with a lower degradation level is higher than the priority of the pumping device 10 with a higher degradation level, and when there is no difference in the degradation level, the priority of the pumping device 10 with a shorter cumulative operation period is higher than the priority of the pumping device 10 with a longer cumulative operation period. The priority is derived based on a function, table, or the like defined in this way.

[0040] The selection unit 215 selects the pumping device 10 for normal operation based on a preset selection criterion, and may select the pumping device 10 for normal operation based on the deterioration level when the deterioration level of any of the plurality of pumping devices 10 exceeds a predetermined threshold value (hereinafter referred to as the "reference switching threshold value"). For example, when the maximum value of the deterioration levels in the plurality of pumping devices 10 (hereinafter simply referred to as the "maximum value of the deterioration level") is below the reference switching threshold value, the selection unit 215 selects the pumping device 10 for normal operation based on the second selection criterion, and when the maximum value of the deterioration level exceeds the reference switching threshold value, the selection unit 215 may select the pumping device 10 for normal operation based on the first selection criterion.

[0041] The selection unit 215 may change the weight of the first selection criterion with respect 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 with respect to the second selection criterion based on the relationship between the multi-stage reference switching threshold value and the maximum value of the deterioration level. As an example, when the maximum value of the deterioration level is below the minimum reference switching threshold value, the selection unit 215 selects the pumping device 10 for normal operation based only on the second selection criterion, and increases the weight of the first selection criterion with respect to the second selection criterion each time the maximum value of the deterioration level exceeds the reference switching threshold value, and when the maximum value of the deterioration level exceeds the maximum reference switching threshold value, the selection unit 215 may select the pumping device 10 for normal operation based only on the first selection criterion. The selection unit 215 cancels the selection of the pumping device 10 for normal operation as 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 for normal operation is selected, the pumping control unit 216 outputs a drive start command to the power conversion device 100 corresponding to the pumping device 10 for normal operation. In response, the pumping control unit 116 of the power conversion device 100 starts pumping water by the pumping device 10 for normal operation. That is, the pumping control unit 216 causes water to be pumped by the pumping device 10 selected by the selection unit 215.

[0043] When the selection of the pumping device 10 for normal operation is cancelled, the pumping control unit 216 outputs a drive stop command to the power conversion device 100 corresponding to the pumping device 10 for 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 for normal operation.

[0044] When the secondary-side pressure (for example, the detected value by the pressure sensor 30) of the pumping device 10 for normal operation is insufficient, the controller 200 may be configured to also pump water to at least one pumping device 10 not selected by the selection unit 215. For example, the controller 200 may further include an additional selection unit 217.

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

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

[0047] The additional selection unit 217 may be configured to select a pumping device 10 having a higher deterioration level compared to 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 value, the additional selection unit 217 may be configured to also select a pumping device 10 whose deterioration level exceeds the threshold value. For example, the additional selection unit 217 may be configured to also select a pumping device 10 whose deterioration level exceeds the above maximum reference switching threshold value.

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

[0049] The deterioration notification unit 218 may be configured to notify the user of the change in the relationship between the alert thresholds at multiple levels and the maximum value of the deterioration level. For example, the deterioration notification unit 218 may be configured to notify the user of the increase in the deterioration level each time the rising deterioration level exceeds the alert threshold. The increase in the deterioration level can be notified by, for example, a change in the display content on the liquid crystal monitor or a change in the color of the warning lamp.

[0050] The deterioration notification unit may be further configured to notify which of the pumping devices 10 has a deterioration level exceeding the alert threshold. Which of the pumping devices 10 has a deterioration level exceeding the alert threshold can be notified, for example, by displaying the identification information of the pumping device 10 whose deterioration level has exceeded the alert threshold on the liquid crystal monitor. Also, which of the pumping devices 10 has a deterioration level exceeding the alert threshold can be notified by which of the warning lamps provided for each pumping device 10 is lit.

[0051] FIG. 3 is a block diagram illustrating the hardware configuration of the power conversion system 20. As shown in FIG. 3, the power conversion device 100 includes a switching circuit 120, a current sensor 130, and a control circuit 140.

[0052] The switching circuit 120 operates according to a command from the control circuit 140 (for example, an electrical signal from the input / output port 144) and functions as the above-described 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 according to an electrical signal (for example, a gate signal) from the input / output port 144. The switching element is, for example, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor). The current sensor 130 operates according to a command from the control circuit 140 (for example, an electrical signal from the input / output port 144) and functions as the above-described current detection unit 114. 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, for example, a non-volatile semiconductor memory. When a corresponding pressure feeding device 10 is selected from a plurality of pressure feeding devices 10 based on the degradation level of the pressure feeding device 10, the storage 143 stores a program for causing the power conversion device 100 to output a drive current to the motor 12 of the corresponding pressure feeding device 10 so as to operate the corresponding pressure feeding device 10, and to estimate the degradation level of the corresponding pressure feeding device 10 based on information regarding the driving force of the corresponding pressure feeding device 10 (for example, the driving 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 100 described above.

[0054] The memory 142 temporarily stores a program loaded from the storage medium of the storage 143 and the calculation results by the processor 141. The processor 141 executes the above program 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 an input power supply, and performs input / output of electrical signals with the switching circuit 120, the current sensor 130, and the controller 200 according to a command from the processor 141.

[0055] The controller 200 has 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 has a computer-readable storage medium, such as a non-volatile semiconductor memory. The storage 223 stores a program that causes the controller 200 to select at least one pumping device 10 from a plurality of pumping devices 10 based on the deterioration level estimated by at least one power conversion device 100, and to output a drive current to the motor 12 from the power conversion device 100 corresponding to the selected at least one pumping device 10 so as to pump water by the selected at least one pumping device 10. For example, the storage 223 stores a program for configuring the functional modules of the controller 200 described above.

[0056] Note that 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. This storage stores a program that causes the power conversion system 20 to estimate the deterioration level of one of the plurality of pumping devices 10 based on information regarding the driving force of any one of the plurality of pumping devices 10, select at least one pumping device 10 from the plurality of pumping devices 10 based on the estimated deterioration level, and pump water by the selected at least one pumping device 10.

[0057] The memory 222 temporarily stores the program loaded from the storage 223 and the calculation results by the processor 221. The processor 221 executes the above application in cooperation with the memory 222. The display device 224 includes, for example, a liquid crystal monitor, an alarm lamp, etc., and is used for information display to the user. The input / output port 225 performs input / output of electrical signals between the pressure sensor 30 and the power conversion device 100 according to a command 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 functions by a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) integrating the same.

[0059] Note that the configuration of the power conversion system 20 shown above is merely an example and can be changed as appropriate. For example, in the above example, one controller 200 is provided for a plurality of power conversion devices 100, but it is not limited thereto, and a plurality of controllers 200 may be provided for the plurality of power conversion devices 100 respectively (see FIG. 4). In this case, at least one of the plurality of controllers 200 can configure the functional modules of the above-described controller 200. Further, the functional modules of the controller 200 may be configured by any one 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〕 Subsequently, as an example of the fluid pumping method, a control procedure of a plurality of pumping devices 10 executed by the power conversion system 20 will be exemplified. This control procedure includes estimating the deterioration level of one of the plurality of pumping devices 10 based on information regarding the driving force of any one of the plurality of pumping devices 10, selecting at least one pumping device 10 from the plurality of pumping devices 10 based on the estimated deterioration level, and pumping water by the selected at least one pumping device 10.

[0061] FIG. 6 is a flowchart illustrating a control procedure for a plurality of pressure feed 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 the detection value by the pressure sensor 30 as the information on the secondary-side pressure, and the selection unit 215 checks whether or not the detection value is lower than the pressure lower limit value. When it is determined that the detection value by the pressure sensor 30 is not lower than the pressure lower limit value, the power conversion system 20 executes step S01 again. Thereafter, step S01 is repeated until the detection value by the pressure sensor 30 is lower than the pressure lower limit value.

[0062] When it is determined that the detection value by the pressure sensor 30 is lower than the pressure lower limit value, the power conversion system 20 executes steps S02, S03, S04, and S05. In step S02, based on the deterioration level stored in the deterioration level information storage unit 212, the selection unit 215 selects the pressure feed device 10 to be normally operated. In step S03, the pressure feed control unit 216 outputs a drive start command to the power conversion device 100 corresponding to the pressure feed device 10 to be normally operated (hereinafter referred to as "the power conversion device 100 for normal operation"). In response thereto, the pressure feed control unit 116 of the power conversion device 100 starts the pressure feed of water by the pressure feed device 10 to be normally operated. 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 detection value by the pressure sensor 30 as the information on the secondary-side pressure, and the selection unit 215 checks whether or not the detection value exceeds the pressure upper limit value. When it is determined in step S05 that the detection value does not exceed the pressure upper limit value, the power conversion system 20 executes step S06. In step S06, the additional selection unit 217 checks whether or not the detection value by the pressure sensor 30 is lower than the additional threshold value.

[0064] When 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 device 10 for the additional operation target from among the plurality of pumping 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 device 10 for 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 device 10 for 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] When 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. Thereafter, until the detected value by the pressure sensor 30 exceeds the pressure upper limit value, the pumping of water by the pumping device 10 for the normal operation target continues, and if necessary, the pumping of water by the pumping device 10 for the additional operation target also continues.

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

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

[0068] Note that in the above-described procedure, the degradation level is estimated once after the operation of the pumping device 10 is stopped, but the timing of estimating the degradation level is not necessarily limited to this. For example, the estimation of the degradation level may be repeated during operation. In this case, the pumping device 10 targeted for operation may be switched during operation according to the increase in the degradation level.

[0069] 〔Effects of this Embodiment〕 As described above, the fluid pumping system 1 includes a plurality of pumping devices 10 for pumping water, a degradation level estimation unit 115 that estimates the degradation level of one of the plurality of pumping devices 10 based on information regarding the driving force of any 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 degradation level estimated by the degradation level estimation unit 115, and a pumping control unit 216 that causes the pumping device 10 selected by the selection unit 215 to pump water.

[0070] According to this fluid pumping system 1, since the selection criteria are automatically changed based on the deterioration level, it is possible to preferentially operate the pumping device 10 with a low deterioration level. As a result, the progress of deterioration of the pumping device 10 with a high deterioration level can be suppressed. Therefore, it is effective in reducing the maintenance frequency. In addition, suppressing the progress of deterioration of the pumping device 10 with a high deterioration level can also contribute to improving the operation efficiency, suppressing vibration, and suppressing noise, etc.

[0071] The selection unit 215 may select at least one pumping device 10 based on a preset selection criterion and the deterioration level estimated by the deterioration level estimation unit 115. In this case, at a stage where the deterioration of any of the pumping devices 10 has not progressed, a plurality of pumping devices 10 can be properly used according to the desired conditions by setting the selection criterion.

[0072] The selection unit 215 may select at least one pumping device 10 based on a selection criterion defined to preferentially select the pumping device 10 with a short cumulative operation period over the pumping device 10 with a long cumulative operation period and the deterioration level.

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

[0074] The selection unit 215 may select at least one pumping device 10 such that the operation period of the pumping device 10 with a high deterioration level is shorter than that 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 surely prioritized.

[0075] When the secondary pressure in the pumping device 10 selected by the selection unit 215 is insufficient, 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 a plurality of pumping devices 10. During the period when the pumping control unit 216 causes the pumping device 10 selected by the selection unit 215 to pump water, the pumping control unit 216 may also cause the pumping device 10 selected by the additional selection unit 217 to pump water. In this case, by suppressing the progress of deterioration in the pumping device 10 with a high deterioration level, the available period of the pumping device 10 as an additional operation target can be extended. Therefore, in a configuration that switches between an operation mode that does not use the additional operation target (hereinafter referred to as the "normal operation mode") and an operation mode that uses the additional operation target (hereinafter referred to as the "parallel operation mode"), it is more effective to suppress the progress of deterioration in the pumping device 10 with a high deterioration level.

[0076] The additional selection unit 217 may select a pumping device 10 with a higher deterioration level compared to the pumping device 10 selected by the selection unit 215. The operation period of the pumping device 10 as an additional operation target is shorter compared to the operation period of the pumping device 10 as an operation target. Therefore, by assigning the pumping device 10 with a high deterioration level as an additional operation target, it is possible to suppress the progress of deterioration in the pumping device 10 with a high deterioration level and effectively utilize the pumping device 10.

[0077] The selection unit 215 does not select a pumping device 10 whose deterioration level exceeds a predetermined threshold value, and the additional selection unit 217 may also select a pumping device 10 whose deterioration level exceeds the threshold value. In this case, it is possible to more reliably suppress the progress of deterioration in the pumping device 10 with a high deterioration level and effectively 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 value. In this case, it is possible to more reliably optimize the maintenance timing.

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

[0080] The pumping device 10 is electric, 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] As described above, the embodiments have been explained. However, the present invention is not necessarily limited to the above-described forms, and various modifications are possible without departing from the gist thereof. The application target of the power conversion system 20 is not necessarily limited to the fluid pumping system. The power conversion system 20 is applicable to any mechanical system as long as it is a mechanical system that selectively operates a plurality of mechanical devices.

Explanation of reference numerals

[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 electric pumping devices for pumping a fluid, A plurality of power conversion units that respectively output drive currents corresponding to current commands to the plurality of pumping devices, A force data acquisition unit that acquires the magnitude of the current command as force data from each of the plurality of power conversion units, A deterioration level estimation unit that estimates the deterioration level of each of the plurality of pumping devices based on the magnitude of the vibration of the force data, A selection unit that selects at least one pumping device from the plurality of pumping devices based on the deterioration level of each 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 so as to pump the fluid by the at least one pumping device selected by the selection unit, A fluid pumping system comprising the same.

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. The fluid pumping system according to claim 2, wherein the selection unit selects the at least one pumping device based on the selection criterion defined to preferentially select the pumping device with a short cumulative operation period over the pumping device with a long cumulative operation period and the deterioration level.

4. The fluid pumping system according to claim 2, wherein the selection unit selects the at least one pumping device based on the selection criterion, and when the deterioration level of any one of the plurality of pumping devices exceeds a predetermined threshold, the selection unit 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 the operation period of the pumping device with a high deterioration level is shorter than the operation period of the pumping device with a low deterioration level.

6. The system further comprises an additional selection unit that 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 pressure feeding control unit causes a fluid to be pressure-fed also to the pressure feeding device selected by the additional selection unit during a period in which a fluid is being pressure-fed to the pressure feeding device selected by the selection unit, in the fluid pressure feeding system according to any one of claims 1 to 5.

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

8. The selection unit does not select the pressure feeding device in which the deterioration level exceeds a predetermined threshold value. The additional selection unit also selects the pressure feeding device in which the deterioration level exceeds the threshold value, in the fluid pressure feeding system according to claim 7.

9. The fluid pressure feeding system according to any one of claims 1 to 8 further includes a deterioration notification unit that notifies a user that the deterioration level has exceeded a predetermined threshold value.

10. The deterioration notification unit further notifies which of the pressure feeding devices has a deterioration level exceeding the threshold value, in the fluid pressure feeding system according to claim 9.

11. A plurality of power conversion units that respectively output drive currents corresponding to current commands to a plurality of electric pressure feeding devices, A force data acquisition unit that acquires the magnitude of the current command as force data from each of the plurality of power conversion units, A deterioration level estimation unit that estimates the deterioration level of each of the plurality of pressure feeding devices based on the magnitude of the vibration of the force data, A selection unit that selects at least one pressure feeding device from the plurality of pressure feeding devices based on the deterioration level of each of the plurality of pressure feeding devices estimated by the deterioration level estimation unit, A pressure feeding control unit that causes the drive current to be output from at least one power conversion unit corresponding to the at least one pressure feeding device to the at least one pressure feeding device so as to pressure-feed a fluid by the at least one pressure feeding device selected by the selection unit, and a power conversion system.

12. Obtaining the magnitude of the current command as force data from each of a plurality of power conversion devices that respectively output drive currents corresponding to current commands to a plurality of electric pressure feeding devices, Estimating the deterioration level of each of the plurality of pressure feeding devices based on the magnitude of the vibration of the force data, Selecting at least one pressure feeding device from the plurality of pressure feeding devices based on the deterioration level of each of the plurality of pressure feeding devices estimated. A fluid pumping method, comprising: causing a driving current to be output from at least one power conversion device corresponding to the at least one pumping device so as to pump a fluid by the selected at least one pumping device.

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