JP2019011733A - Pump device and control method of pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly convenient pump device and a control method of a pump device capable of continuing to supply a liquid even when a protection function is operated. A pump device includes a pump, an electric motor for driving the pump, an inverter device for supplying power to the electric motor, and a control device for outputting a control signal to the inverter device to control the operation of the pump. , The control device comprises a protective means for stopping the pump and restarting the pump stopped by the protective means when a current equal to or higher than the protection level flows through the inverter device. It has a retry means and a protection level raising means for raising the protection level each time the pump is restarted by the retry means. [Selection diagram] FIG. 5

Description

  The present invention relates to a pump device and a control method of the pump device.

  Conventionally, an electric pump that drives a pump by an electric motor is known as a pump device. When starting such an electric pump, a start torque shortage may occur due to variations in the performance of electronic components of the control device and the use status (environment) of the pump, resulting in a failure state. In this case, since a current corresponding to a required torque flows on the motor side, a current larger than the rated current tends to flow depending on the state of the load.

  Therefore, on the control device side, the protection function is operated to stop the pump when the current flows more than the set value. In addition, when the above event occurs, a retry operation that repeats starting the pump again is performed a plurality of times to determine the failure. As a pump device having such a protection function, for example, a water supply device using a variable speed pump described in Patent Document 1 is known.

Japanese Patent Laid-Open No. 1-190989

  By the way, if the pump device is stopped due to the overtorque state of the electric motor as described above, the protection relating to the failure factor can be established, but on the other hand, the supply of the liquid delivered from the pump is lost and the convenience for the user is reduced. .

  The present invention has been made in view of the above problems, and provides a highly convenient pump device and a pump device control method capable of continuing to supply liquid even when a protective function is activated. With the goal.

  (1) A pump device according to an aspect of the present invention includes a pump, an electric motor that drives the pump, an inverter device that supplies electric power to the electric motor, and an operation of the pump that outputs a control signal to the inverter device. A control device that controls the pump device, and the control device is stopped by the protection means that stops the pump when a current of a protection level or more flows to the inverter device, and the protection means Retry means for restarting the pump, and protection level raising means for raising the protection level each time the pump is restarted by the retry means.

(2) In the pump device according to (1), the initial protection level is a rated current value of the electric motor, and the protection level raising means is configured to calculate the inverter device from the rated current value of the electric motor. The protection level may be increased stepwise every time the pump is restarted by the retry means until the current allowable value is reached.
(3) In the pump device described in (1) or (2) above, the protection means causes the inverter device to have a level equal to or higher than the protection level each time the protection level raising means raises the protection level. You may shorten the detection time for detecting whether the electric current is flowing.
(4) The pump device according to (1) to (3), wherein the control device is configured such that, after the pump is restarted by the retry unit, a current flowing through the inverter device is a predetermined time, You may have a reset means which returns the said protection level to the initial protection level, when it is less than the rated current value of an electric motor.
(5) In the pump device described in (1) to (4) above, in the control device, the current flowing through the inverter device becomes a current limit control level set lower than the protection level. Current limit control means for limiting the current flowing through the inverter device, and current limit control level raising means for raising the current limit control level each time the pump is restarted by the retry means. May be.

  (6) A pump device control method according to an aspect of the present invention is a pump device control method including a pump, an electric motor that drives the pump, and an inverter device that supplies electric power to the electric motor, A protection step for stopping the pump, a retry step for restarting the pump stopped by the protection step, and a restart of the pump by the retry step when a current exceeding a protection level flows to the inverter device. A protection level increasing step for increasing the protection level each time.

  According to the above aspect of the present invention, since the liquid can be continuously supplied even when the protection function is activated, the convenience of the pump device is enhanced.

It is a front view which shows the pump apparatus 1 which concerns on 1st Embodiment. It is a longitudinal cross-sectional view which shows the internal structure of the pump casing 30 which concerns on 1st Embodiment. It is a block diagram showing a schematic structure of pump device 1 concerning a 1st embodiment. It is a block diagram which shows the structure of the control unit 4 which concerns on 1st Embodiment. It is a graph which shows the relationship between the overcurrent protection level which concerns on 1st Embodiment, and the frequency | count of a retry. It is a graph which shows the relationship between the overcurrent detection time which concerns on 1st Embodiment, and the frequency | count of a retry. It is a graph which shows the relationship between the electric current allowable level of the power element of the inverter apparatus 70 which concerns on 1st Embodiment, and time. It is an operation | movement flow of the pump apparatus 1 which concerns on 1st Embodiment. In 1st Embodiment, it is a flow which shows the retry operation | movement which restarts the pump 2 once stopped. It is a block diagram which shows schematic structure of 1 A of pump apparatuses which concern on 2nd Embodiment. It is a graph which shows the relationship between the overcurrent protection level which concerns on 2nd Embodiment, a current limiting control level, and the number of retries. In 2nd Embodiment, it is a flow which shows the retry operation | movement which restarts the pump 2 once stopped.

  Hereinafter, an embodiment of a pump device and a control method of the pump device will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a front view showing a pump device 1 according to the first embodiment. FIG. 2 is a longitudinal sectional view showing the internal structure of the pump casing 30 according to the first embodiment.
As shown in FIG. 1, a pump device 1 includes a pump 2 that pumps water, an electric motor 3 (see FIGS. 3 and 4 to be described later) that is provided on the back side of the pump 2, and drives the pump 2. And a control unit 4 for controlling the operation. The pump 2, the electric motor 3, and the control unit 4 are supported by a synthetic resin unit base 5, and are substantially entirely covered by a synthetic resin unit cover 6.

  The pump 2 is a cascade pump that is also referred to as a friction pump, and includes an impeller 20 and a pump casing 30 that forms a pump chamber 31 that houses the impeller 20 as illustrated in FIG. 2. As shown in FIG. 1, a pump casing cover 50 is attached to the front side of the pump casing 30. When the pump casing cover 50 is removed, the impeller 20 can be accessed. As shown in FIG. 2, the impeller 20 is formed in a disk shape having a large number of grooves 21 in the peripheral portion, and the peripheral portion causes the water present in the pump chamber 31 to rotate almost once. While boosting.

  Although the pump 2 is small, a single impeller 20 can obtain a lift comparable to several stages of a centrifugal pump, and is suitable for the purpose of a small capacity and high lift. Moreover, since the cascade pump has a self-priming property, it is suitable for pumping water and well water stored in a water receiving tank installed at a position lower than the pump 2.

  As shown in FIG. 1, a suction port 7 exposed from the unit cover 6 and a discharge port 8 are provided on the front surface of the pump device 1. The suction port 7 communicates with one end 32a of an internal flow path 32 formed inside the pump casing 30 shown in FIG. 2, and the discharge port 8 communicates with the other end 32b of the internal flow path 32. Yes. A pump chamber 31 and a steam / water separation chamber 33 are formed in the internal flow path 32.

  In the internal flow path 32, a flow check valve 35 is provided in the suction flow path 34 from the one end 32 a to the pump chamber 31. The flow check valve 35 is provided at a position higher than the pump chamber 31, and prior to driving the pump 2, the interior of the pump chamber 31 is filled to ensure a water level necessary for self-priming, and when the pump 2 is stopped. It has a role of preventing back flow of water and always filling the pump chamber 31 with water. That is, the flow check valve 35 closes the suction flow path 34 by its own weight when the pump 2 is stopped, and is pushed up by water (including air at the time of startup) that goes up the suction flow path 34 when the pump 2 is driven. Open the suction channel 34.

  A steam / water separation chamber 33 is disposed downstream of the pump chamber 31. A baffle 37 in which the liquid discharged from the pump chamber 31 collides is disposed in the connection channel 36 between the pump chamber 31 and the steam separation chamber 33 in the internal channel 32. A hole 33 a communicating with the pump chamber 31 is formed at the bottom of the steam / water separation chamber 33. The hole 33a is for returning the water separated from the air in the steam / water separation chamber 33 to the pump chamber 31 again during the self-priming operation at the start of the pump 2, thereby generating a negative pressure in the pump chamber 31. The air in the suction flow path 34 is eliminated, and water is sucked up.

  A priming port 38 is formed above the steam / water separation chamber 33. The priming port 38 is closed by a priming faucet 39. The priming faucet 39 is opened when the pump 2 is installed or the like when the pump casing 30 is not filled with water and before the pump 2 is started. The separation chamber 33 is filled up to the water level 40 at the time of priming. When the above-described pump 2 is driven, a self-priming operation is performed, and when the air in the suction flow path 34 disappears and water rises, the self-priming operation ends, and the steam-water separation chamber 33 and the steam-water separation chamber 33 After the downstream side is filled with water, the pumping operation is performed by driving the pump 2.

  Of the internal flow path 32, a pressure sensor 42 is provided in the discharge flow path 41 from the steam / water separation chamber 33 to the other end 32b. The pressure sensor 42 is disposed above the priming water level 40 and detects the pressure (discharge pressure) of the discharge channel 41 filled with water after the self-priming operation is completed.

  Further, the discharge passage 41 is provided with a pressure tank (not shown). The pressure tank has a rubber bladder built in the pressure vessel. When the discharge pressure of the pump 2 increases, the air outside the bladder is compressed and water is stored in a pressurized state. Further, for example, as the pressure in the discharge channel 41 decreases with the use of water, the compressed air expands and pushes the stored water to the discharge channel 41. In this way, even after the pump 2 is started, water can be supplied from the pressure tank to the discharge passage 41 for a while even if the rotational speed is not increased to a sufficient level for water supply.

FIG. 3 is a block diagram illustrating a schematic configuration of the pump device 1 according to the first embodiment. FIG. 4 is a block diagram showing a configuration of the control unit 4 according to the first embodiment.
As shown in FIG. 3, the control unit 4 includes an inverter device 70 that supplies electric power to the electric motor 3 and a control device 60 that outputs a control signal to the inverter device 70 to control the operation of the pump 2. A commercial power source 100 is connected to the inverter device 70, and AC power supplied from the commercial power source 100 is converted into AC power having a desired frequency by the inverter device 70 and supplied to the electric motor 3. As shown in FIG. 3, the flow check valve 35 described above includes a check valve 35 a that prevents backflow of water and a flow switch 35 b that detects a decrease in the flow rate of water flowing through the pump 2.

  The control device 60 includes an I / O unit (not shown), a calculation unit, and a storage unit. The I / O unit is connected to various sensors such as the pressure sensor 42, the flow switch 35b, the voltage sensor 71, the current sensor 72, and the temperature sensors 80, 81, 82, and outputs the detection results of the various sensors to the arithmetic unit. At the same time, a command signal from the arithmetic unit (for example, the rotational speed of the pump 2) is output to the inverter device 70. The I / O unit may include an external output terminal (not shown) for outputting the state of the pump device 1 to the outside using a contact signal or communication, or a GUI for displaying the state of the pump device 1. May be. The calculation unit of the control device 60 is realized by, for example, a CPU (central processing unit), and various control programs of the pump device 1 are executed. For example, a command signal to be output to the inverter device 70 is calculated based on detection results of various sensors or the like input via the I / O unit, and the command signal is output to the I / O unit. As an example of a control program executed by the calculation unit of the control device 60, the start / stop of the pump 2 is instructed by the discharge pressure and the flow rate lowering signal, or the set pressure PA is notified to the set pressure PA. The discharge pressure constant control or the estimated terminal pressure constant control is calculated, the target pressure SV is calculated, and the rotational speed of the pump 2 is controlled so that the current pressure PV becomes the target pressure SV. Further, the calculation unit obtains information indicating the state of the pump device 1 (discharge pressure, rotation speed, accumulated operation time, accumulated operation number, etc.) and stores it in the storage unit. The storage unit includes various memories that store various control programs executed by the calculation unit, various information used by the calculation unit, and various types of information obtained by the calculation unit. In addition, the I / O unit, the calculation unit, and the storage unit of the control device 60 described above may be provided in each of the pump control unit 60a and the inverter control unit 60b or may be used in combination.

  As illustrated in FIG. 4, the control device 60 includes a pump control unit 60a and an inverter control unit 60b. As described above, the flow rate reduction signal and the measured value of the discharge pressure are input to the pump control unit 60a, and the discharge pressure of the pump 2 is kept constant at the target pressure. Then, a command for the rotational speed of the pump 2 is issued to the inverter control unit 60b. The inverter control unit 60b generates a PWM signal for minimizing the difference between the target rotation speed of the pump 2 sent from the pump control unit 60a and the actual rotation speed of the pump 2.

  The inverter device 70 is an inverter circuit that generates an AC voltage based on the PWM signal from the inverter control unit 60b and applies the AC voltage to the motor 3. The converter unit 70a, the DC voltage smoothing circuit 70b, and the inverter unit 70c and a gate driver 70d. The converter unit 70 a includes a rectifier circuit configured by a diode or the like in order to convert a three-phase AC voltage supplied from the commercial power supply 100 into a DC voltage. The DC voltage smoothing circuit 70b includes a capacitor, and smoothes the DC voltage converted by the converter unit 70a.

  The inverter unit 70c includes a power element such as an IGBT (insulated gate bipolar transistor) and a plurality of diodes connected in parallel to the power element. The inverter unit 70c has three-phase from the DC voltage smoothed by the DC voltage smoothing circuit 70b. It is comprised so that an alternating voltage may be produced | generated. Based on the PWM signal from the inverter control unit 60b, the gate driver 70d generates a gate drive signal for switching the power elements of the inverter unit 70c.

  A voltage sensor 71 and a current sensor 72 arranged on the secondary side of the inverter circuit are connected to the inverter control unit 60b. The measured values of voltage and current obtained by the voltage sensor 71 and the current sensor 72 are input to the inverter control unit 60b. The inverter control unit 60b estimates the actual rotational speed of the electric motor 3 (and the pump 2) from the measured current value fed back, and PWM for minimizing the difference between the estimated rotational speed and the target rotational speed. Generate a signal. Note that the voltage sensor 71 and the current sensor 72 may be omitted if the control device 60 can predict the voltage and current on the secondary side of the inverter circuit.

  In the example shown in FIG. 4, temperature sensors 80, 81, and 82 for measuring these temperatures are attached to the pump 2, the electric motor 3, and the inverter device 70, respectively. The pump control unit 60a performs inverter control so that the rotation speed of the electric motor 3 is lower than that during steady operation when the measured value of the temperature of at least one of the temperature sensors 80, 81, 82 reaches a predetermined upper limit. A command may be issued to the unit 60b.

  As shown in FIG. 3, the control device 60 described above, as a protection function of the electric motor 3 and the inverter device 70, includes a protection means 61 that stops the pump 2 when a current equal to or higher than the protection level flows to the inverter device 70. Retry means 62 for restarting the pump 2 stopped by the protection means 61, protection level raising means 63 for raising the protection level every time the pump 2 is restarted by the retry means 62, and the raised protection level as the initial protection Resetting means 64 for returning to the level. With these protection functions, it is possible to prevent a failure due to an overcurrent of the electric motor 3 and the inverter device 70 from occurring.

  The calculation unit of the control device 60 determines whether or not a current equal to or higher than the protection level has flowed into the inverter device 70 from the measured value of the current sensor 72, that is, whether or not an abnormality (overcurrent) has occurred. Control (control by protection means 61, retry means 62, protection level raising means 63, and reset means 64) is performed. In the control device 60, for example, a program for performing the above-described various controls (control by the protection means 61, the retry means 62, the protection level raising means 63, and the reset means 64) is stored in the storage unit of the control device 60. The program is executed by the calculation unit of the control device 60, and the calculation result is output to each device by the I / O unit of the control device 60.

Hereinafter, the operation of the pump device 1 configured as described above (the control method of the pump device 1), specifically, the overcurrent protection operation by the control device 60 will be described in detail.
FIG. 5 is a graph showing the relationship between the overcurrent protection level (protection level) and the number of retries according to the first embodiment. FIG. 6 is a graph showing the relationship between the overcurrent detection time and the number of retries according to the first embodiment. FIG. 7 is a graph showing the relationship between the current allowable level of the power element of the inverter device 70 according to the first embodiment and time. FIG. 8 is an operation flow of the pump device 1 according to the first embodiment. FIG. 9 is a flowchart showing a retry operation for restarting the pump 2 that has been stopped in the first embodiment.

  As shown in FIG. 8, in the operation flow of the pump device 1, first, the control device 60 determines whether or not the activation condition of the pump 2 is satisfied (step S <b> 1). When the activation condition of the pump 2 is satisfied (in the case of “YES”), the control device 60 starts acceleration of the electric motor 3 to activate the pump 2 (step S2). On the other hand, when the starting condition of the pump device 1 is not satisfied (in the case of “NO”), the control device 60 waits until the starting condition of the pump device 1 is satisfied in a state where the pump 2 is stopped (step). S3).

  When the pump 2 is started in step S2, the current value increases with time as shown in FIG. Here, the control device 60 determines whether or not an abnormality (overcurrent) has occurred based on the measured value of the current sensor 72 (step S4). Specifically, the control device 60 determines that an abnormality has occurred when the measured value of the current sensor 72 exceeds the overcurrent protection level 1 (initial protection level) shown in FIG. The overcurrent protection level 1 of the present embodiment is a setting value that can be changed. For example, the overcurrent protection level 1 is set to the same level as the rated current value of the motor 3, that is, the current value of the motor 3 when the pump 2 is rated. It is good to be.

  When the measured value of the current sensor 72 exceeds the overcurrent protection level 1 (in the case of “YES”), that is, when a current equal to or higher than the overcurrent protection level flows to the inverter device 70, the control device 60 has an abnormality. Then, the pump 2 is stopped (protection step). Thereafter, the control device 60 performs a retry operation for restarting the stopped pump 2 (step S5: retry step). On the other hand, when the measured value of the current sensor 72 does not exceed the overcurrent protection level 1 (in the case of “NO”), the control device 60 performs a normal operation (for example, a known discharge pressure constant control) (step). S6).

  As shown in FIG. 9, in the retry operation, first, the control device 60 increases the count of the retry counter by 1 (step S11). Next, the control device 60 increases the overcurrent protection level by one level (step S12). Specifically, as shown in FIG. 5, the control device 60 increases the protection level from the overcurrent protection level 1 to the overcurrent protection level 2 (protection level increasing step). The increase level of the protection level in step S12 is a set value that can be changed. For example, when the overcurrent protection level 1 is set to 100%, the increase range is set to about 10%.

  Next, the control device 60 reduces the overcurrent protection time (step S13). The overcurrent protection time is a detection time for detecting whether or not current exceeding the overcurrent protection level is flowing through the inverter device 70. Specifically, as shown in FIG. 6, the control device 60 shortens the detection time 2 at the overcurrent protection level 2 at the first retry time than the detection time 1 at the overcurrent protection level 1. . The overcurrent protection time (detection time) is counted when the measured value of the current sensor 72 exceeds the overcurrent protection level corresponding to the number of retries.

  The overcurrent protection level 2 is set to a setting value that can be changed. In this embodiment, the overcurrent protection level 2 is set to a level higher than the rated current value of the electric motor 3 that is an example of the overcurrent protection level 1. When the current flows, a heavy burden is applied to the inverter device 70. As shown in FIG. 7, the current allowable value of the inverter device 70, specifically, the relationship between the current allowable value of the power element and the time is in an inversely proportional relationship. Therefore, even if a current exceeding the rated current value of the electric motor 3 flows to the power element of the inverter device 70 for a short time, the power element can tolerate the current.

  Next, the control device 60 determines whether or not a preset retry interval has elapsed since the pump 2 was stopped (step S14). Here, the retry interval may be a setting value that can be changed. When the retry interval has elapsed (in the case of “YES”), the control device 60 starts acceleration of the electric motor 3 in order to restart the pump 2 (step S15). On the other hand, when the retry interval has not elapsed (in the case of “NO”), the control device 60 waits for the retry interval to elapse and restarts the pump 2.

  Next, the control device 60 determines whether an abnormality (overcurrent) has occurred based on the measured value of the current sensor 72 (step S16). Specifically, the control device 60 determines that an abnormality has occurred when the measured value of the current sensor 72 exceeds the overcurrent protection level 2 (first retry) shown in FIG. When the measured value of the current sensor 72 exceeds the overcurrent protection level 2 (in the case of “YES”), that is, when a current exceeding the overcurrent protection level 2 flows to the inverter device 70, the control device 60 has an abnormality. As a result, the pump 2 is stopped (protection step).

  Next, the control device 60 determines whether or not the retry counter is equal to or greater than a preset number of retries N (step S17). The retry count N is a setting value that can be changed. For example, the retry count N is set to about 5 (N = 5). When the retry counter is N times or less, the process returns to step S11, and as described above, the retry counter is increased by one and the overcurrent protection level is increased by one. Thus, the control device 60 increases the overcurrent protection level every time the pump 2 is restarted.

  There is a limit to the increase of the overcurrent protection level, and the limit (maximum allowable level) is determined by the allowable current value of the power element of the inverter device 70 shown in FIG. That is, the control device 60 increases the overcurrent protection level step by step every time the pump 2 is restarted from the rated current value of the electric motor 3 to the current allowable value of the inverter device 70. If the number of retries until the overcurrent protection level reaches the allowable current value of the inverter device 70 is N, and the retry counter is greater than or equal to the number of retries N in step S17 (if “YES”), the pump 2 is confirmed, and further restart of the pump 2 is stopped (step S18).

  On the other hand, if the determination in step S16 is “NO”, that is, as shown in FIG. 5, the measured value of the current sensor 72 has an overcurrent protection level corresponding to the number of retries n at the number of retries n (less than 5). If not exceeded, the control device 60 performs constant current control to return to the normal operation state (step S19). That is, there is a case where the cause of the abnormality (for example, fixing of the impeller 20 or the like) is removed after repeating the retry several times, and when the overcurrent no longer occurs, the control device 60 Control to return to the operation state.

  Next, the control device 60 determines whether or not the measured value (actual current value) of the current sensor 72 is equal to or lower than the rated current value (overcurrent protection level 1) of the motor 3 as a result of the constant current control (step). S20). The constant current control is control that keeps the current constant so that the current does not exceed the limit level for a predetermined time that is a setting value that can be changed. When the measured value of current sensor 72 is larger than the rated current value of electric motor 3 (in the case of “NO”), control device 60 returns to step S19 and continues the constant current control. On the other hand, when the measured value of the current sensor 72 is equal to or lower than the rated current value of the electric motor 3 (in the case of “YES”), the control device 60 clears the retry counter (step S21).

Specifically, the control device 60 determines that the current state has returned to the normal operation state when the current flowing through the inverter device 70 remains within the rated current value of the motor 3 for a certain period of time, and sets the overcurrent protection level. Return to overcurrent protection level 1 (initial protection level) (reset step). Thereafter, the control device 60 performs a normal operation (for example, known discharge pressure constant control) (step S22).
Thus, the retry operation of the pump device 1 is completed.

  Various setting values including the overcurrent protection level (protection level) in FIG. 5 described above, the overcurrent detection time and the number of retries in FIG. 6, the current allowable level of the power element of the inverter device 70 in FIG. It is preferable that the setting can be changed from the I / O unit while being stored in the storage unit. As specific means for realizing the various operations described in FIGS. 5 to 7, the operation flow of the pump device 1 in FIG. 8, and the flow showing the retry operation in FIG. Based on the value, each control program is executed by the arithmetic unit, and a control signal is mainly output from the I / O unit to the inverter device 70. In other words, the protection means 61, retry means 62, protection level raising means 63, and reset means 64 included in the control device 60 are means for realizing the above-described protection step, retry step, protection level raising step, and reset step, respectively. Then, based on various values input in the I / O unit, the control unit executes a control program according to each step, and the I / O unit sends various control signals (for example, start, stop, Output rotation speed, etc.).

  Therefore, the pump device 1 includes the pump 2, the electric motor 3 that drives the pump 2, the inverter device 70 that supplies electric power to the electric motor 3, and the control that outputs the control signal to the inverter device 70 to control the operation of the pump. Device 60. The control device 60 includes a protection means 61 for stopping the pump 2 when a current of a protection level or higher flows in the inverter device 70, a retry means 62 for restarting the pump 2 stopped by the protection means 61, and a retry means. And a protection level raising means 63 for raising the protection level every time the pump 2 is restarted by 62.

  As described above, according to this embodiment described above, it is possible to continue supplying the liquid without stopping immediately even when the protection function is activated (when the overcurrent protection level 1 is exceeded). Therefore, the convenience of the pump device 1 is increased.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent configurations and steps as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 10 is a block diagram illustrating a schematic configuration of a pump device 1A according to the second embodiment.
As shown in FIG. 10, in the second embodiment, the control device 60 serves as a protection function that prevents overcurrent from flowing through the electric motor 3 and the inverter device 70, thereby generating the pump device 1 of the first embodiment. In addition to the protection means 61, retry means 62, protection level raising means 63, and reset means 64 described above, the current flowing through the inverter device 70 has reached a current limit control level set lower than the overcurrent protection level. In this case, current limiting control means 65 for limiting the current flowing through the inverter device 70 and current limiting control level increasing means 66 for increasing the current limiting control level each time the pump 2 is restarted by the retry means 62 are provided.

FIG. 11 is a graph showing the relationship between the overcurrent protection level and current limit control level and the number of retries according to the second embodiment. FIG. 12 is a flow showing a retry operation for restarting the pump 2 that has been stopped in the second embodiment.
As shown in FIG. 11, the current limit control level is a setting value that can be changed, and is set lower than the overcurrent protection level. The control device 60 provides the current limit control level and performs PI control or PID control on the rotation speed of the pump 2 so that the measured value of the current sensor 72 does not exceed the current limit control level, and the pump 2 is immediately stopped. To prevent it. In other words, the above-described protection function is prevented from operating excessively by stepping up the current at a level lower than the overcurrent protection level.

  As shown in FIG. 12, in the retry operation of the second embodiment, step S12A for increasing the current limit control level is added between step S12 and step S13. This step S12A is a step of increasing the current limit control level according to the number of retries, similarly to the overcurrent protection level. The increase range of the current limit control level is a setting value that can be changed, and is preferably set similarly to the increase range of the overcurrent protection level. As a result, even if the overcurrent protection level increases, the difference between the overcurrent protection level and the current limit control level is maintained constant, and it becomes easy to perform PI control and PID control.

  In the retry operation of the second embodiment, if “NO” in the step S16, a step S16A for determining whether or not the measured value of the current sensor 72 exceeds the current limit control level is added before the step S19. Has been. When the measured value of the current sensor 72 does not exceed the current limit control level (in the case of “NO”), the process returns to step S16. On the other hand, when the measured value of the current sensor 72 exceeds the current limit control level (in the case of “YES”), the process proceeds to step S19, and current limit control (constant current control) is performed.

  Between step S19 and step S20, step S19A is determined in which the control device 60 determines whether or not the measured value of the current sensor 72 exceeds the overcurrent protection level. When the measured value of the current sensor 72 exceeds the overcurrent protection level also by the current limiting control (in the case of “YES”), the process proceeds to step S17. If the retry counter is less than N, the process returns to step S11 to increase the retry counter by one and raise the overcurrent protection level and the current limit control level by one. Thus, the control device 60 increases the overcurrent protection level and the current limit control level each time the pump 2 is restarted.

  On the other hand, when the measurement value of the current sensor 72 does not exceed the overcurrent protection level in the determination of step S19A (in the case of “NO”), the process proceeds to step S20. Thereafter, the flow is the same as in the first embodiment, and the measured value (actual current value) of the current sensor 72 is equal to or lower than the rated current value (overcurrent protection level 1) of the motor 3 (in the case of “YES”). ), The control device 60 clears the retry counter (step S21), and returns to normal operation (for example, known discharge pressure constant control).

  As described above, in the second embodiment, the current limit control level is provided, and the increase of the current is stepped on at a level lower than the overcurrent protection level to prevent the pump 2 from being stopped, and the liquid is more liquid than in the first embodiment. Therefore, the convenience of the pump device 1 is enhanced.

  Although preferred embodiments of the present invention have been described and described above, it should be understood that these are exemplary of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other changes can be made without departing from the scope of the invention. Accordingly, the invention is not to be seen as limited by the foregoing description, but is limited by the scope of the claims.

For example, the temperature of the load (for example, the temperature of the pump casing 30 (handling liquid temperature), the winding temperature of the electric motor 3, the temperature of the inverter circuit of the inverter device 70) is also detected by the temperature sensors 80, 81, 82 at the same time. The temperature rise during the repeated retry operation may be recorded, and the retry may be repeated until it reaches a certain set value or more. Moreover, when it becomes more than a set value, a pump may be stopped and a failure may be decided.
Further, for example, load vibration (for example, bearing vibration, pump device vibration) may be detected in the same manner as the temperature, and a set value may be provided in the same manner to determine continuation of the retry or failure.
Further, for example, when the restart of the pump 2 is successful, the overcurrent protection level may be lowered stepwise instead of immediately returning the overcurrent protection level to the normal level.

  Further, for example, various setting values such as the current limit control level, the increase width of the current limit control level, and the number of retries of the second embodiment described above are stored in the storage unit of the control device 60 and set from the I / O unit. It should be possible to change.

  That is, the control device 60 according to the second embodiment described above has a current that limits the current flowing through the inverter device 70 when the current flowing through the inverter device 70 reaches a current limit control level set lower than the protection level. Limit control means 65 and current limit control level raising means 66 for raising the current limit control level each time the pump 2 is restarted by the retry means 62 are provided. Specifically, the current limit control means 65 acquires the current flowing through the inverter device 70 at the I / O unit of the control device 60 and stores it in the storage unit. The storage unit stores a current limit control level set lower than the protection level. When the arithmetic unit determines that the current flowing through the inverter device 70 has reached the current limit control level, the I / O unit outputs a command for limiting the current flowing through the inverter device 70 to the inverter device 70. Similarly, the current limit control level raising means 66 is a means for raising the current limit control level every time the pump 2 is restarted by the retry means 62 by the control device 60. As described above, even when the protection function is activated (when the overcurrent protection level 1 is exceeded), the liquid supply can be continued without stopping immediately, so that the convenience of the pump device 1A is high. Become.

  The pump device 1 described in the above embodiment includes one pump, but the number of pumps may be two or more. In that case, the electric motor 3 and the inverter apparatus 70 should just provide the number according to the number of pumps. Further, the inverter device 70 may be used by switching the connection to the pump to be started.

DESCRIPTION OF SYMBOLS 1 Pump apparatus 1A Pump apparatus 2 Pump 3 Electric motor 4 Control unit 5 Unit base 6 Unit cover 7 Suction port 8 Discharge port 20 Impeller 21 Groove 30 Pump casing 31 Pump chamber 32 Internal flow path 32a One end part 32b The other end part 33 Water separation chamber 33a Hole 34 Suction flow path 35 Flow check valve 35a Check valve 35b Flow switch 36 Connection flow path 37 Baffle 38 Nominal outlet 39 Nominal faucet 40 Nominal water level 41 Discharge flow path 42 Pressure sensor 50 Pump casing cover 60 Controller 60a Pump control section 60b Inverter control section 61 Protection means 62 Retry means 63 Protection level raising means 64 Reset means 65 Current limit control means 66 Current limit control level raising means 70 Inverter device 70a Converter section 70b DC voltage smoothing circuit 70c Invar 70d Gate driver 71 Voltage sensor 72 Current sensor 80 Temperature sensor 81 Temperature sensor 82 Temperature sensor 100 Commercial power supply S1 Step S2 Step S3 Step S4 Step S5 Step S6 Step S11 Step S12 Step S12A Step S13 Step S14 Step S15 Step S16 Step S16A Step S17 Step S18 Step S19 Step S19A Step S20 Step S21 Step S22 Step

Claims (6)

A pump,
An electric motor for driving the pump;
An inverter device for supplying electric power to the motor;
A control device that outputs a control signal to the inverter device to control the operation of the pump, and a pump device comprising:
The control device includes:
Protection means for stopping the pump when a current of a protection level or more flows to the inverter device;
Retry means for restarting the pump stopped by the protection means;
And a protection level raising means for raising the protection level each time the pump is restarted by the retry means. The initial protection level is the rated current value of the motor,
The protection level raising means raises the protection level step by step every time the pump is restarted by the retry means, from the rated current value of the electric motor to the current allowable value of the inverter device. The pump device according to claim 1.   The protection means shortens a detection time for detecting whether or not a current equal to or higher than the protection level flows in the inverter device each time the protection level raising means raises the protection level. The pump device according to claim 1 or 2.   After the pump is restarted by the retry means, the control device sets the protection level to an initial protection level when the current flowing through the inverter device remains within the rated current value of the motor for a certain time. The pump device according to any one of claims 1 to 3, further comprising reset means for returning to the initial position. The control device includes:
Current limiting control means for limiting the current flowing through the inverter device when the current flowing through the inverter device reaches a current limiting control level set lower than the protection level;
The pump according to claim 1, further comprising a current limit control level increasing unit that increases the current limit control level each time the pump is restarted by the retry unit. apparatus. A pump,
An electric motor for driving the pump;
An inverter device that supplies power to the electric motor, and a control method for a pump device comprising:
A protection step for stopping the pump when a current of a protection level or more flows to the inverter device;
A retry step of restarting the pump stopped by the protection step;
And a protection level raising step for raising the protection level each time the pump is restarted by the retry step.

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