JP4212219B2 - Electric pump device and control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric pump device used in a sewage tank or the like.
[0002]
[Prior art]
Conventionally, as this type of electric pump device, as shown in FIG. 4, a connecting pipe 2 fixedly installed at the bottom of a water storage tank (sewage tank) 1 with an anchor bolt or the like, and a discharge port 3 b are connected to the connecting pipe 2. The submersible motor pump 3 installed at the bottom of the water storage tank 1 in a state of being connected to one end opening, the water distribution pipe 4 connected to the other end opening of the connecting pipe 2, and the submersible motor pump 3 are controlled. And a pump control panel 10 that performs the same operation.
[0003]
The submersible motor pump 3 incorporates an induction motor 3c and an impeller 3d, and rotates the impeller 3d by driving the induction motor 3c so as to suck in sewage in the water storage tank 1 from the suction port 3a. . The sewage sucked in this way is fed from the connecting pipe 2 through the water distribution pipe 4 to the water tank 5 of a predetermined water destination.
[0004]
By the way, in this kind of electric pump device, there is one in which the rotational speed of the induction motor 3c is inverter-controlled by an inverter provided in the pump control panel 10, and this induction motor 3c corresponds to the output frequency from the inverter. It will be driven at the rotational speed.
[0005]
The characteristics of the electric pump device in this case are as shown in FIG. 5A (however, mainly the characteristics of a centrifugal pump, a vortex pump, etc.).
[0006]
That is, FIG. 5A shows a constant rotational speed (output frequency f from the inverter).₀Is a diagram showing the relationship between the HQ characteristic (discharge amount-total lift characteristic) of the submersible motor pump 3 and the pipe resistance curves (1) to (3) (H indicated by a one-dot difference line). -Q characteristics will be described later). Among these, the pipe resistance curve (1) is when the pipe resistance HL is large (HL = HL) because the distribution pipe 4 is long or thin.₁), The pipe resistance curve (2) is when the pipe resistance HL is medium (HL = HL)₂), The pipe resistance curve (3) is when the pipe resistance HL is small (HL = HL) because the distribution pipe 4 is short and thick._Three) Respectively. The total head H is the actual head Ha (see FIG. 4), which is the difference between the water level of the water tank 1 at the water source and the water level of the water tank 5 at the water destination, and its pipe resistance HL (connection pipe 2 and distribution). In FIG. 5 (a), only the loss HL in the piping or the like is considered with the actual lifting height Ha = 0 for easy understanding.
[0007]
In FIG. 5A, the intersection of the HQ characteristic of the submersible motor pump 3 and the pipe resistance curves {circle around (1)} to {circle around (3)} is the operating point of the submersible motor pump 3.
[0008]
Accordingly, as shown in FIG. 5A, it can be seen that the discharge amount Q decreases as the pipe resistance HL increases.
[0009]
Further, the drive current I and the power amount P of the induction motor 3c for each discharge amount Q are as shown by the solid lines in FIGS. 5B and 5C, and as the discharge amount Q of the pump increases, The load amount of the induction motor 3c increases, and both the current I and the power consumption amount P increase.
[0010]
Therefore, a constant rotational speed (output frequency f₀When the submersible motor pump 3 is operated under the condition of a constant), when the actual head Ha and the loss H1 fluctuate and the discharge amount Q is large, the induction motor 3c has its drive current I and power consumption P. Both of the current I and the power consumption P of the induction motor 3c are small, and the capacity of the induction motor 3c is sufficiently extracted. It is not preferable because it is not in a state.
[0011]
Therefore, in order to draw out the capacity of the induction motor 3c without excess or deficiency, in the electric pump disclosed in Japanese Patent Laid-Open No. 9-96291, the electric current I and the electric power consumption P of the electric motor are set to predetermined constant values. A method for controlling the output frequency f or the output voltage V from the inverter to the motor is disclosed.
[0012]
In this case, when the output frequency f or the output voltage V is inverter-controlled so that the consumption current I of the electric motor 3c becomes a constant value Io, the total head H, current I, and electric energy P with respect to the discharge amount Q are shown in FIG. ) To FIG. 5 (c), and the capacity of the electric motor 3c can be pulled out without excess or deficiency.
[0013]
[Problems to be solved by the invention]
However, in this control method, control is performed so that the value of the current I or the amount of electric power P is constant regardless of the operating condition. Therefore, when the impeller 3d is blocked by dirt or the like, the blocking is released. There is a problem that the current I or the amount of electric power P sufficient to generate the necessary torque cannot be obtained and the operation stops. In that case, the user of the pump device has to pull up the submersible motor pump 3 from the water reservoir 1 and disassemble it, and remove the filth causing the blockage.
[0014]
More specifically, the current I is a predetermined I_OThe case where the inverter control is performed so as to be constant will be described.
[0015]
FIG. 6 shows that the current I is a predetermined target current value I_OIt is a flowchart which shows the process controlled to become fixed.
[0016]
That is, the current I is a predetermined target current value I_OIn order to control to be constant, as shown in FIG. 6, the current I of the induction motor 3c is detected, and in step T1, the detected current I and the target current value I are detected._OAnd compare. Here, the detected current I is the target current value I_OIf it is determined that the output frequency f is lower than that, the process proceeds to step T2 to increase the output frequency f. In step T1, the detected current I and the target current value I_OAre the same, the process proceeds to step T3 to maintain the output frequency f as it is. In step T1, the detected current I is changed to the target current value I._OIf it is determined that the output frequency f is greater than the threshold value, the process proceeds to step T4 to decrease the output frequency f.
[0017]
When the control for making the current I constant is performed as described above, the relationship between the output frequency f from the inverter, the output voltage V, the torque T, the current I, and the electric energy P is shown in FIGS. As shown in (d).
[0018]
As shown in FIG. 7A, the base frequency f₀In the following region, V / f is constant and constant torque operation is performed, and the base frequency f₀In the above region, constant output operation with a constant voltage V is performed. FIG. 7B shows the relationship between the pump load torque curves (1) to (3) and the fT characteristic (frequency-torque characteristic) of the induction motor 3c. The pump load torque curves {circle around (1)} to {circle around (3)} correspond to the pipe resistance curves {circle around (1)} to {circle around (3)} in FIG. 5, respectively, that is, the pump load torque curve {circle around (1)} is when the pipe resistance HL is large. (HL = HL₁), Pump load torque curve (2) is when the pipe resistance HL is medium (HL = HL)₂), Pump load torque curve (3) is when pipe resistance HL is small (HL = HL)_Three) Respectively.
[0019]
  In this case, as shown in FIG. 7B, the induction motor 3c has a pump load torque curve.(1)-(3)And the f-T characteristic (frequency-torque characteristic) of the induction motor 3c, the pipe resistance HL1₁If (curve(1)) Includes a relatively large output frequency f₁The pipe resistance is HL₂If (curve(2)) Medium output frequency f₀Operated with pipe resistanceH L _Three If (curve(3)) Has a relatively low output frequency f_ThreeIt is driven by. That is, pipe resistanceH LThe output frequency f increases as the value increases (in the meantime, the HQ characteristic and the pipe resistance curve indicated by the one-dot chain line in FIG. 5A).(1)-(3)The output frequency f at the operating point of the submersible motor pump 3 that is the intersection of₁, F₀, F_ThreeBecome).In other than this paragraph, the curve (1), the curve (2), and the curve (3) are each indicated by a notation in which numbers are circled.
[0020]
However, when the electric pump device is blocked by dirt or the like, an excessive load is applied to the electric motor 3c and the drive current I tends to increase. For this reason, in the flowchart of FIG. 6, the process of proceeding from T1 to T4 (the process of reducing the drive current I) is repeatedly performed, and the output frequency f continues to decrease as shown in FIG. The submersible motor pump 3 will eventually stop. Although a slight increase in the current I can be expected due to the impact at the time of closing, the current I is set to a constant value I._OAs a result, the output torque T becomes smaller than the closing release torque Tc, and the closing state cannot be released.
[0021]
SUMMARY OF THE INVENTION An object of the present invention is to provide an electric pump device that can drive an electric motor in an appropriate state without excess or deficiency, and that can prevent a clogging stop caused by dirt or the like, and a control method therefor.
[0022]
[Means for Solving the Problems]
  In order to solve the above-mentioned problem, the electric pump device according to claim 1 varies the output frequency from the frequency variable drive unit to the pumping water motor according to the load amount of the motor.It is the drive current, electric energy or torque of the electric motorAn electric pump device that variably controls the value of a drive system electrical element to be constant, the electrical element detection means for detecting the value of the drive system electrical element, and a drive system electrical element in advance The first target value and the second target value larger than the first target value and the lower limit value of the output frequency or output voltage to the motor are set, and the drive system electrical element detected by the electrical element detection means When the output frequency or the output voltage falls below the lower limit value while giving an output frequency change command to the frequency variable drive section so that the value of the drive system is equal to the first target value, the drive system electrical element Control means for giving an output frequency change command to the variable frequency drive unit so that the value of the value coincides with the second target value.
[0023]
According to a second aspect of the present invention, the control means, after giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element matches the second target value, When the output frequency or output voltage exceeds the lower limit value, an output frequency change command is given to the frequency variable drive unit so that the value of the drive system electrical element again matches the first target value. It may be.
[0024]
According to a third aspect of the present invention, after the control means gives an output frequency change command to the frequency variable drive section so that the value of the drive system electrical element matches the second target value, In a state where the output frequency or the output voltage does not exceed the lower limit value, the occurrence of an abnormality may be notified through a notification unit when a predetermined time has elapsed.
[0025]
Further, as described in claim 4, the control means, after giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element coincides with the second target value, The electric motor may be reversely rotated when a predetermined time elapses in a state where the output frequency or the output voltage does not exceed the lower limit value.
[0026]
According to a fifth aspect of the present invention, the control means, after giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element matches the second target value, In a state where the output frequency or the output voltage does not exceed the lower limit value, the motor may be accelerated by increasing the output frequency when a predetermined time has elapsed.
[0027]
According to a sixth aspect of the present invention, the control means, after giving an output frequency change command to the frequency variable drive section so that the value of the drive system electrical element matches the second target value, The electric motor may be stopped when a predetermined time elapses in a state where the output frequency or the output voltage does not exceed the lower limit value.
[0028]
  Furthermore, in the control method of the electric pump device according to claim 7, the output frequency to the electric motor varies according to the load amount of the electric motor.It is the drive current, electric energy or torque of the electric motorA control method for an electric pump device that variably controls a drive system electrical element value to be constant, so that the detected drive system electrical element value coincides with a preset first target value. When the output frequency or the output voltage falls below a preset lower limit value while the output frequency is variably controlled, a value of the drive system electrical element is larger than the first target value. The output frequency is variably controlled so as to coincide with the target value.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
{Embodiment}
Hereinafter, an electric pump device according to an embodiment of the present invention will be described.
[0030]
This electric pump device includes a pump control panel 20 shown in FIG. 1 instead of the pump control panel 10 in the electric pump device shown in FIG. In addition, about the other components, ie, the submersible motor pump 3, the connecting pipe 2, and the water distribution pipe 4, since the electric pump apparatus which concerns on this Embodiment is also provided with the thing of the same structure, in the following description, those About the component, the same code | symbol is used and those description is abbreviate | omitted.
[0031]
The pump control panel 20 is configured such that an inverter unit 30 that drives an induction motor 3c by receiving power supply from a commercial power source and the like, and a main control unit 25 that controls the inverter unit 30 are housed in a predetermined case. .
[0032]
The inverter unit 30 controls the main circuit unit 31 as a frequency variable drive unit for supplying power of a predetermined output frequency and a predetermined output voltage to the induction motor 3c, and the output frequency and output voltage from the main circuit unit 31. And a current detection unit 33 for detecting a current I (drive current I of the induction motor 3c) output from the main circuit unit 31 to the induction motor 3c.
[0033]
The main circuit unit 31 includes a converter circuit that converts commercial AC power to DC, an inverter circuit that converts smoothed DC power to AC power having a predetermined frequency and voltage, and the power source on the input side thereof. The line 21 is connected to a commercial AC power source and the like, and the output side power line 22 is connected to the induction motor 3c. The induction motor 3c is connected to the induction motor 3c at an output frequency and output voltage according to a setting command given from the control unit 32 in the inverter. It is configured to be drivable.
[0034]
The current detection unit 33 is inserted in the middle of the power line 22 from the main circuit unit 31 to the induction motor 3c, detects the current I flowing from the main circuit unit 31 to the induction motor 3c, and outputs the detection signal. It is comprised so that it may output to the control part 32 in an inverter.
[0035]
The in-inverter control unit 32 uses a general microcomputer including a CPU, a ROM, a RAM, and the like, and all the arithmetic operations are executed by a software program stored in advance, and are supplied from the current detection unit 33. On the basis of the detected current signal, the value of the detected drive current I is a predetermined target current value I._OAnd a constant current control function for controlling the output frequency f and the output voltage V from the main circuit unit 31 so as to coincide with each other.
[0036]
That is, the in-inverter control unit 32 obtains the drive current value I based on the current detection signal given from the current detection unit 33, and the detected current I and a predetermined target current value I._OCompare the size with. The predetermined target current value I_OIs a value given by the main control unit 25 and its target current value I_OThe setting criteria will be described later. As a result of the comparison, the detected current I becomes the target current value I_OIf the output frequency f is smaller than the output frequency f, a setting command for the output frequency f increased from the output frequency f at the time of detection is given to the main circuit unit 31. Further, the detection current I and the target current value I_OAre the same, the setting command of the same output frequency f as the output frequency f at the time of detection is given to the main circuit unit 31. Furthermore, the detection current I is a target current value I_OIf the output frequency f is greater than the output frequency f, a setting command for an output frequency f smaller than the output frequency f at the time of detection is given to the main circuit unit 31. As a result, the output frequency from the main circuit unit 31 is increased or decreased in accordance with the setting commands, so that the drive current I is controlled to be constant. The setting command of the output frequency f given to the main circuit unit 31 is also given to the main control unit 25 in this way.
[0037]
The inverter unit 30 has a base frequency f₀In the following, V / f constant control is performed and the base frequency f₀In the above, constant voltage control is performed (see FIG. 7A). Therefore, when the setting command of the output frequency f is given from the inverter control unit 32 to the main circuit unit 31, the inverter control unit An output voltage setting command corresponding to V / f constant control or voltage constant control is given from 32 to the main circuit unit 31.
[0038]
The main control unit 25 is a general microcomputer provided with a CPU, ROM, RAM, and the like, and all the arithmetic operations are executed by a software program stored in advance. The first target current value I is supplied to the inverter control unit 32 according to the output frequency f given by_O1Or the second target current value I_O2And a target current value I_O2And a timer function for giving a stop command for the induction motor 3c to the in-inverter control unit 32 under a predetermined condition after elapse of a predetermined time t and reporting an abnormality through the speaker 40 as a notification means.
[0039]
That is, the main control unit 25 outputs the output frequency f given by the inverter control unit 32 and a preset lower limit frequency f._LAnd f ≧ f_LIn the case (normal operation state), the first target current value I_O1give. As a result, the inverter unit 30 causes the detected current I to be the first target current value I._O1The output frequency f and the output voltage V are controlled so as to coincide with each other. Here, the first target current value I_O1Is a target value in the normal operation state of the inverter unit 30, and is preferably set to be equal to or lower than the rated current of the induction motor 3c. The lower limit frequency f_LIs a value for detecting clogging due to clogging of dirt, etc., so that the base frequency f₀A sufficiently lower value, for example, the base frequency f₀Is 60 Hz, f_L= It is preferable to set the value within the range of 20 to 40 Hz.
[0040]
On the other hand, f <f_LIn the case of (blockage occurrence state), the inverter target control unit 32 receives the first target current value I._O1Larger than 2 target current value I_O2give. As a result, the inverter unit 30 determines that the detected current I is the second target current value I._O2The output frequency f and the output voltage V are controlled so as to coincide with each other. Here, the second target current value I_O2Is a value for causing the induction motor 3c to generate a torque sufficient to release the blockage, and is preferably set as high as possible. For example, the first target current value I_O1Can be set to a value that is at least twice as large as. The second target current value I_O2The constant current control at the time is based on the premise of a short time operation (described below), so that the second target current value I_O2However, there is no problem even if the current is more than the rated current of the induction motor 3c.
[0041]
Further, the main control unit 25 sends a second target current value I to the in-inverter control unit 32._O2F <f_LIt is determined whether a certain time t has elapsed, and when the certain time t has elapsed, a stop command is given to the inverter control unit 32. Thereby, induction motor 3c stops and it can prevent the burning. At the same time, an abnormality is reported through the speaker 40. Here, the predetermined time t is the second target current value I._O2Is set to a time that can be withstood by the induction motor 3c driven by (1), for example, about 10 seconds.
[0042]
<Operation>
Next, the operation of this electric pump device will be described with reference to FIGS.
[0043]
As an initial setting, the first target current value I is stored in the memory of the main control unit 25 in advance._O1, Second target current value I_O2, And lower limit frequency f_LIs stored.
[0044]
Then, when the electric pump device shifts to a normal operation state (the operation up to here is omitted), the processing shown in the flowchart of FIG. 2 is performed.
[0045]
That is, in step S1, the first target current value I is transferred from the main control unit 25 to the in-inverter control unit 32._O1In step S2, the inverter control unit 32 detects the detected drive current I and the first target current value I based on the detection signal from the current detection unit 33._O1A comparison is made with the size. The drive current I is the first target current value I_O1(For example, the drive current I tends to decrease when the discharge amount Q decreases under a certain condition of the output frequency f), the process proceeds to step S3, and at the time when the current I is detected. A command for setting the output frequency f that is increased from the output frequency f is given to the main circuit unit 31. As a result, the output frequency f from the main circuit portion 31 increases, and the rotation speed of the induction motor 3c increases. In step S2, the drive current I and the first target current value I_O1Are determined to be the same, the process proceeds to step S4, and a setting command for the same output frequency f as the output frequency f when the current I is detected is given to the main circuit unit 31. In step S2, the driving current I is changed to the first target current value I._O1(For example, when the discharge amount Q increases under a constant condition of the output frequency f, the drive current I tends to increase), the process proceeds to step S5 and the output at the time when the current I is detected. A setting command for the output frequency f that is reduced below the frequency f is given to the main circuit unit 31. As a result, the output frequency f from the main circuit unit 31 is reduced, and the rotational speed of the induction motor 3c is reduced.
[0046]
Then, after the processes of steps S3 to S5 are performed, the process proceeds to step S6, and the output frequency f and the lower limit frequency f given from the inverter control unit 32 by the main control unit 25 are processed._LIs determined, and f <f_LIf this is not the case (when no blockage has occurred), the process returns to step S1 and the processes of steps S1 to S6 are performed. In a state where no blockage has occurred, the processes in steps S1 to S6 are repeated, and the induction motor 3c is driven at an appropriate output frequency f in accordance with fluctuations in the suction amount (total lift H, etc.).
[0047]
  on the other hand,Impeller 3dIn the state of being blocked by foreign matter, an excessive load is applied to the induction motor 3c and the drive current I increases. Therefore, the process of proceeding from step S2 to step S5 is repeatedly performed at the beginning of the blocking, and the output frequency f decreases. (F in FIGS. 3A to 3D)₀To f_LSee the process for And the output frequency f₁Is the lower limit frequency f_LSmaller than f in step S6₁<F_LIs determined, the target current value I is transferred from the main control unit 25 to the in-inverter control unit 32 in step S7._OAs a first target current value I_O1Instead of the second target current value I_O2Is given. As a result, the inverter unit 30 determines that the detected current I is the second target current value I._O2The output frequency f and the output voltage V are controlled so as to coincide with each other, and the torque T, the drive current I, and the electric energy P of the induction motor 3c increase rapidly (f in FIGS. 3A to 3D).₂reference).
[0048]
Next, in step S8, the target current value I_OTo the second target current value I_O2It is determined whether or not a predetermined set time t or more has elapsed since the setting command to give is set. If the set time t or more has not passed, the process proceeds to step S2. Thereby, the main control unit 25 converts the detected current I into the second target current value I._O2In step S2, the second target current value I suddenly increases._O2So I <I_O2In step S3, the output frequency f is increased (f in FIGS. 3A to 3D).₂To f '_LSee the process for
[0049]
Here, when the increased torque T exceeds the torque Tc required to release the blockage (foreign matter clogging) (see FIG. 3B), the blockage (foreign matter clogging) is released, and then the output frequency f is increased. Lower limit frequency f_LUntil the target value of the detected current I is I_O2The processing of steps S2, S3, S6 to S8 is repeated with the setting being made. Eventually, the output frequency f becomes the lower limit frequency f._LAnd f <f in step S6_LIf not, the process proceeds from step S6 to step S1, and the target value of the detected current I is changed to the first target current value I._O1Thus, the process returns to the normal operation state in which the processes of steps S1 to S6 are repeatedly performed (actually, the frequency f ′ that proceeds from step S6 to step S1 since there is hysteresis in the frequency during acceleration)._LIs f_L+2 to 3 Hz).
[0050]
On the other hand, when the increased torque T cannot exceed the torque Tc necessary for releasing the blockage and the set time t elapses without releasing the blockage, the determination process in step S8 is affirmed, and the process proceeds to step S9 to proceed to the main control unit 25. To give a stop command to the control unit 32 in the inverter. As a result, the induction motor 3c stops. At the same time, an abnormality is reported through the speaker 40.
[0051]
According to the electric pump device configured as described above, in the normal operation state, the drive current I to the induction motor 3c is the first target current value I._O1Since the output frequency from the main circuit unit 31 of the inverter unit 30 to the induction motor 3c is variably controlled so as to match the above, the induction motor 3c can be driven in an appropriate state according to fluctuations in the head H or the like.
[0052]
Further, the output frequency f from the main circuit unit 31 is a preset lower limit frequency f._LIn the closed state which has become below, the drive current I to the induction motor 3c is the first target current value I._O1Larger second target current value I_O2Thus, since the output frequency f is variably controlled, the output torque T from the electric motor 3c can be increased thereby releasing the closed state. Therefore, it is possible to minimize the lifting operation of the submersible motor pump 3 by the user.
[0053]
Even if the closed state cannot be released by this, the second target current value I_O2After the set time t has elapsed, the drive of the induction motor 3c is stopped so that the induction motor 3c can be prevented from being damaged. In the present embodiment, the speaker 40 is used as the notification means, but other notification means such as a notification means using a patrol light or a telephone line may be used.
[0054]
In addition, since the abnormality is reported through the speaker 40 at this time, the abnormality can be notified to the user, and the work of lifting and disassembling the submersible motor pump 3 can be promoted.
[0055]
{Modification}
In addition, between the said step S8 and step S9 (refer step S10 of FIG. 2), the instruction | command which rotates the induction motor 3c to a reverse direction is given from the main control part 25 to the control part 32 in an inverter, and the induction motor 3c is reversely rotated. You may make it perform the process to make. Thus, when the induction motor 3c is rotated in the reverse direction, the rotation of the impeller 3d is reversed and the blockage is easily released. In this case, it is preferable to reversely rotate the induction motor 3c about once or twice at a speed of 2 seconds / time. Further, when the reverse rotation is performed in this way, after the reverse rotation command is given and the normal rotation command is given again, when the blockage is released by the reverse rotation, the acceleration is resumed and the process returns to step S1. If the closed state is not released even after returning to the normal operating state and reversely rotating, it is not possible to re-accelerate and it is preferable to perform the process of step S9.
[0056]
Alternatively, between step S8 and step S9 (see step S10 in FIG. 2), a command to increase the output frequency f is given regardless of the value of the detected drive current I from the main control unit 25 to the in-inverter control unit 32. Thus, the drive current I and the torque of the induction motor 3c may be increased to try reacceleration (retry operation). In this case, it is preferable to perform a retry operation in which the drive current I is increased about 1 to 2 times at about 2 seconds / time. In this case, if the blockage can be released, the induction motor 3c is reaccelerated, so that the process returns to step S1. On the other hand, when the blockage cannot be released, the induction motor 3c cannot be reaccelerated, so that step S9 is preferably performed.
[0057]
In the present embodiment, the first and second target current values I_O1, I_O2, And the output frequency f is variably controlled so that the detected current I coincides with them. In addition, the detected first and second electric power P or torque T of the induction motor 3c is preset. The output frequency f may be variably controlled so as to coincide with the second target power value or the first and second target output torque values.
[0058]
The output frequency f is lower limit frequency f._LThe target current value I of the current I based on whether or not_OIs the first target current value I_O1To the second target current value I_O2However, when the control is performed so as to output the voltage V corresponding to the output frequency f on a one-to-one basis, such as when the inverter unit 30 performs constant V / f control, Frequency f_LInstead of the lower limit voltage V_LThe output voltage V is set to the lower limit voltage V_LThe target current value I of the current I based on whether or not_OMay be replaced.
[0059]
The present embodiment is mainly for an electric pump device such as a centrifugal pump or a vortex pump, which has a type in which the flow rate Q decreases and the drive current decreases as the pipe resistance increases. The same can be applied to an electric pump device such as a pump in which the drive current increases when the flow rate Q decreases, if the increase / decrease in the output frequency due to the increase / decrease in the drive current is controlled in reverse.
[0060]
Further, the second target current I_O2May be a short-time overload current of the inverter without setting.
[0061]
In this embodiment, each function of the control means is divided into the inverter control section 32 and the main control section 25, but these functions are physically integrated into one control means. Alternatively, each function may be physically allocated to a plurality of control means as necessary.
[0062]
【The invention's effect】
  As described above, according to the electric pump device of the first aspect of the present invention,The drive current, electric energy or torque of the motorElectrical element detection means for detecting a value of the drive system electrical element, a first target value of the drive system electrical element, a second target value larger than the first target value, and an output to the front motor A lower limit value of the frequency or the output voltage is set, and the output frequency is changed in the frequency variable drive unit so that the value of the drive system electrical element detected by the electrical element detection means coincides with the first target value. While giving a command, when the output frequency or output voltage falls below the lower limit value, the frequency variable drive unit issues a command to change the output frequency so that the value of the drive system electrical element matches the second target value. In the normal operation state, the motor can be driven in an appropriate state in accordance with fluctuations in the total lift, etc., and when the motor enters the closed state, the output torque from the motor is increased to the closed state. Release It can cause.
[0063]
According to a second aspect of the present invention, the control means, after giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element matches the second target value, When the output frequency or output voltage exceeds the lower limit value, a command to change the output frequency is given to the variable frequency drive unit so that the value of the drive system electrical element again matches the first target value. By doing so, it is possible to return to the normal operation state after the closure is released.
[0064]
According to a third aspect of the present invention, after the control means gives an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element matches the second target value, When the occurrence of an abnormality is notified via the notification means when a predetermined time has elapsed in a state where the output frequency or output voltage does not exceed the lower limit value, the occurrence of the abnormality is recognized on the operator side. Can do.
[0065]
Furthermore, as described in claim 4, after the control means gives an output frequency change command to the variable frequency drive unit so that the value of the drive system electrical element matches the second target value, If the electric motor is reversely rotated when a predetermined time elapses in a state where the output frequency or output voltage does not exceed the lower limit value, the blockage is easily released.
[0066]
Further, as described in claim 5, after the control means gives an output frequency change command to the variable frequency drive unit so that the value of the drive system electrical element matches the second target value, If the output frequency or output voltage does not exceed the lower limit value and a predetermined time has elapsed, the blockage is easily released even if the output frequency is increased and the motor is accelerated. .
[0067]
According to a sixth aspect of the present invention, after the control means gives an output frequency change command to the variable frequency drive unit so that the value of the drive system electrical element matches the second target value, If the motor is stopped when a predetermined time elapses in a state where the output frequency or the output voltage does not exceed the lower limit value, the motor can be prevented from being burned out.
[0068]
  Moreover, according to the control method of the electric pump device according to claim 7 of the present invention, it is detected.The drive current, electric energy or torque of the motorWhile the output frequency is variably controlled so that the value of the drive system electrical element matches the preset first target value, when the output frequency or the output voltage falls below the preset lower limit value, In order to variably control the output frequency so that the value of the drive system electrical element coincides with a second target value that is larger than the first target value, in a normal operation state, according to fluctuations in the total head, etc. The electric motor can be driven in an appropriate state, and when the electric motor enters the closed state, the output torque from the motor can be increased to release the closed state.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an electrical configuration of an electric pump device according to an embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the electric pump device of the above.
FIG. 3 is a diagram showing a change characteristic during operation of the electric pump device, FIG. 3 (a) is a diagram showing a relationship between an output frequency f and an output voltage V, and FIG. 3 (b) is an output frequency f. 3 (c) is a diagram illustrating the relationship between the output frequency f and the current I, and FIG. 3 (d) illustrates the relationship between the output frequency f and the electric energy P. FIG.
FIG. 4 is an explanatory diagram showing an overall configuration of the electric pump device.
FIG. 5 is a diagram showing a change characteristic during the operation of the electric pump device, FIG. 5 (a) is a diagram showing a relationship between the discharge amount Q and the total lift H, and FIG. FIG. 5C is a diagram showing the relationship between the amount Q and the current I, and FIG. 5C is a diagram showing the relationship between the discharge amount Q and the power amount P.
FIG. 6 is a flowchart showing the operation of a conventional electric pump device.
7A and 7B are diagrams showing a change characteristic during operation of the electric pump device, FIG. 7A is a diagram showing a relationship between an output frequency f and an output voltage V, and FIG. 7B is an output frequency f. 7 (c) is a diagram showing the relationship between the output frequency f and the current I, and FIG. 7 (d) shows the relationship between the output frequency f and the electric energy P. FIG.
FIG. 8 is a diagram showing a change characteristic during operation of the electric pump device, FIG. 8 (a) is a diagram showing a relationship between the output frequency f and the torque T, and FIG. 8 (b) is a diagram showing the output frequency f; FIG. 8C is a diagram showing a relationship between the current I and FIG. 8C is a diagram showing a relationship between the output frequency f and the electric energy P.
[Explanation of symbols]
1 Reservoir
2 Connection pipe
3 Submersible motor pump
3a Suction port
3c induction motor
4 water pipes
20 Pump control panel
25 Main control unit
30 Inverter section
31 Main circuit part
32 Inverter control unit
33 Current detector
40 Speaker

Claims (7)

The output frequency from the variable frequency drive unit to the pumped-up motor is such that the value of the drive system electrical element, which is the drive current, power amount or torque of the motor that varies according to the load amount of the motor, is constant. An electric pump device for variable control,
Electrical element detection means for detecting a value of the drive system electrical element;
The first target value of the drive system electrical element, the second target value larger than the first target value, and the lower limit value of the output frequency or output voltage to the motor are set in advance and detected by the electrical element detection means When the output frequency or output voltage falls below the lower limit value while giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element made coincides with the first target value Control means for giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element coincides with the second target value;
An electric pump device comprising: The electric pump device according to claim 1,
The control means includes
When an output frequency change command is given to the frequency variable drive unit so that the value of the drive system electrical element matches the second target value, and then the output frequency or output voltage exceeds the lower limit value. An electric pump device for giving an output frequency change command to the variable frequency drive unit so that the value of the drive system electrical element again matches the first target value. The electric pump device according to claim 1 or 2,
The control means includes
After giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element coincides with the second target value, the output frequency or the output voltage is not exceeding the lower limit value. An electric pump device that notifies the occurrence of an abnormality via a notification means when a predetermined time has elapsed. The electric pump device according to any one of claims 1 to 3,
The control means includes
After giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element coincides with the second target value, the output frequency or the output voltage is not exceeding the lower limit value. An electric pump device that reversely rotates the electric motor when a predetermined time has elapsed. The electric pump device according to any one of claims 1 to 4,
The control means includes
After giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element coincides with the second target value, the output frequency or the output voltage is not exceeding the lower limit value. An electric pump device that attempts to accelerate the motor by increasing the output frequency when a predetermined time has elapsed. The electric pump device according to any one of claims 1 to 5,
The control means includes
After giving an output frequency change command to the frequency variable drive unit so that the value of the drive system electrical element coincides with the second target value, the output frequency or the output voltage is not exceeding the lower limit value. An electric pump device that stops the electric motor when a predetermined time has elapsed. Control of an electric pump device that variably controls the output frequency to the electric motor so that the value of the drive system electric element, which is the driving current, electric energy or torque of the electric motor, which varies according to the load amount of the electric motor, is constant A method,
The output frequency is variably controlled so that the detected drive system electrical element value matches the first target value set in advance, while the output frequency or output voltage falls below a preset lower limit value. In some cases, the control method of the electric pump device variably controls the output frequency so that the value of the drive system electrical element coincides with a second target value larger than the first target value.

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