CN105452670B - pump system - Google Patents

Abstract

The present invention provides a pump system comprising: a pump unit having an impeller provided in a pump housing, a synchronous motor driving the rotation of the impeller, and an inverter controlling the synchronous motor, the inverter having: A signal input unit for signals of a pressure detection unit installed on the discharge side of the pump unit to detect water pressure, an arithmetic processing unit for determining the rotational speed of the synchronous motor, and a storage unit for storing control parameters required for calculations performed by the arithmetic processing unit , and a power conversion unit that supplies a drive current to the synchronous motor, wherein the arithmetic processing unit performs a process of stopping and restarting the synchronous motor when a pressure change of a predetermined value or more is detected based on a signal from the pressure detection unit, When the synchronous motor does not start normally during the first restart, the second restart is performed at a rate of increase different from that of the synchronous motor at the first restart.

Description

pump system

technical field

The invention relates to a pump system using an inverter controlling a synchronous motor.

Background technique

In the past, an induction motor was mainly used as a drive source of a pump, but now a synchronous motor using a permanent magnet is used from the viewpoint of energy saving and high efficiency. Among synchronous motors, a motor that does not have a magnetic pole position sensor has an advantage that there is no need to worry about failure of the magnetic pole position sensor, and the price can be kept low.

On the other hand, in the case of a synchronous motor that does not have a magnetic pole position sensor, a phenomenon called out-of-synchronization occurs in which the rotational speed recognized by the inverter controlling the motor does not match the actual motor rotational speed. not working state. In the case of a pump, there is a possibility that the required water supply cannot be performed, and the drinking water supply may be cut off or the equipment may stop.

For example, according to the following Patent Document 1, it is possible to detect an abnormality in the rotation state of the motor based on the estimation of the shaft error of the motor.

Patent Document 1: Japanese Patent Laid-Open No. 2012-60781

Contents of the invention

However, even in the out-of-step state, a current corresponding to the induced voltage flows through the motor, and its current value is substantially the same as that in the normal rotation state. Therefore, in the method of estimating the shaft error from the voltage command value and the current detection value described in Patent Document 1, it is difficult to detect out-of-synchronization because the change in the current value is minute.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a technology that can easily detect a step-out in a pump system and restart a motor as necessary to stably drive a load and continue water supply.

In order to solve the above-mentioned problems, in the present invention, as an example, a pump system includes a pump unit having an impeller provided in a pump housing, a synchronous motor that drives the rotation of the impeller, and an inverter that controls the synchronous motor. It has a signal input unit that inputs a signal from a pressure detection unit that detects water pressure provided on the discharge side of the pump unit, an arithmetic processing unit that determines the rotational speed of the synchronous motor, and stores necessary controls for calculations performed by the arithmetic processing unit. A storage unit for parameters, and a power conversion unit for supplying drive current to the synchronous motor, and the arithmetic processing unit stops and restarts the synchronous motor when a pressure change of a predetermined value or more is detected based on a signal from the pressure detection unit. In the starting process, if the synchronous motor does not normally start during the first restart, the second restart is performed at a rate of increase different from that of the synchronous motor at the first restart.

According to the present invention, even when a step-out occurs and the load does not rotate and does not operate, the motor can be quickly restarted to drive the load and continue to operate. Thereby, stable water supply can be performed.

Description of drawings

FIG. 1 is an overall configuration of a pump system in an embodiment of the present invention.

FIG. 2 shows the internal structure of the inverter in the embodiment of the present invention.

Fig. 3 is data content of a storage unit in the embodiment of the present invention.

Fig. 4 is a control flow of the pump in the constant speed operation in the first embodiment of the present invention.

FIG. 5 is a control flow of abnormality processing in the first to third embodiments of the present invention.

Fig. 6 is a control flow of the automatic water supply device under constant water supply pressure automatic operation in the first embodiment of the present invention.

Fig. 7 is a control flow of the pump in constant speed operation in the second embodiment of the present invention.

Fig. 8 is a control flow of the automatic water supply device in the second embodiment of the present invention under constant water supply pressure automatic operation.

Fig. 9 is a control flow of automatic operation of the automatic water supply device with constant water supply pressure in the third embodiment of the present invention.

Fig. 10 is a control flow (example 1) of pump characteristic calculation processing in the third embodiment of the present invention.

11 is a control flow (example 2) of pump characteristic calculation processing in the third embodiment of the present invention.

Fig. 12 is an explanatory diagram of pressure changes due to out-of-synchronization in the first embodiment of the present invention.

13 is an explanatory diagram of a pressure change and a load current value change due to out-of-synchronization in the second embodiment of the present invention.

Fig. 14 is an explanatory diagram of pump characteristics in the second embodiment of the present invention.

Fig. 15 is an explanatory diagram 1 of pump characteristics in the third embodiment of the present invention.

Fig. 16 is an explanatory diagram 2 of pump characteristics in the third embodiment of the present invention.

detailed description

In the first embodiment of the present invention, in a synchronous motor that is driving a pump, an abnormality (out of step) is detected from a change in pump secondary side pressure.

Check the secondary side pressure of the pump. If the change exceeds the specified value, stop the pump first. After restarting, check the secondary side pressure of the pump again. When the secondary side pressure reaches the specified value, it is judged that a step-out has occurred. .

First, the overall structure of the pump system of the present invention is shown in FIG. 1 . In FIG. 1 , a pump 10 provided with an impeller inside a pump housing is driven by a motor 20 . The motor 20 is a synchronous motor without a magnetic pole position sensor. Furthermore, the motor 20 is connected to an inverter 30 , and the inverter 30 drives the motor 20 while changing the frequency of the output current, thereby changing the rotation speed of the motor 20 . A pressure detection unit 11 is provided on the secondary side piping of the pump 10 to detect the pump discharge side pressure.

The internal structure of the inverter 30 is shown in FIG. 2 . A power receiving unit that receives power supplied to the inverter 30 is connected to an AC-DC conversion unit 31 , and the received AC power is converted into a DC voltage. The DC voltage is reconverted by the DC-AC conversion unit 32 into AC power at a frequency instructed by the arithmetic processing unit 34 . When changing the rotational speed of the load, a signal is input to the signal input unit 33 . Based on the input signal, the frequency output from the arithmetic processing unit 34 is determined, and an instruction is given to the DC-AC conversion unit 32 so as to generate an AC power supply of the frequency. The storage unit 35 stores control parameters required for calculations by the calculation processing unit 34 in advance, and the calculation processing unit 34 reads and writes the storage content of the storage unit 35 as necessary.

The content stored in the storage unit 35 composed of a volatile memory and a nonvolatile memory is shown in FIG. 3 . In addition, instead of providing a storage unit inside the inverter 30, a storage device may be installed outside the inverter.

The rotational speed (command frequency to the motor) HzN at the start of abnormality judgment is recorded at address 1000 of the volatile memory. In address 1001, the pump secondary side pressure (discharge side pressure) HN at the start of abnormality determination is recorded. The control parameter at address 1002 is not used in the first embodiment. Address 1003 stores remaining time TN1 of a timer for setting a period for abnormality determination processing, and address 1004 stores remaining time TN2 of a timer for checking the frequency of occurrence of abnormality. The result of the abnormality judgment, that is, the number of times CN of restarting is stored in address 1005 . The control parameters from address 1006 to address 1009 are not used in the first embodiment of the present invention. In address 1010, the first pump secondary side pressure (discharge side pressure) Hm is stored. In address 1011, the frequency increase rate D1 at the time of pump restart (first time) is stored, and in address 1012, the frequency increase rate D2 at the time of pump restart (second time and later) is stored.

The pressure reference value HDG on the secondary side of the pump used for determination in the abnormality determination processing is stored in advance at address 2001 of the nonvolatile memory. The control parameter at address 2002 is not used in the first embodiment of the present invention. In the address 2008, a cycle TM1 for performing abnormality judgment processing is stored in advance. The setting time TM2 of the timer for checking the occurrence frequency of an abnormality is stored in address 2009 in advance.

In the address 2010, a parameter SLD for selecting whether to execute the abnormality judgment function is stored in advance. When the user sets SLD to 0, the abnormality determination process is not performed, and when the user sets SLD to 1, the abnormality determination process is executed when the condition is satisfied. The control parameters from address 3100 to address 3215 are not used in the first embodiment.

Address 7001 stores in advance a parameter SLA for selecting whether to output a failure signal when the number of restarts performed reaches the number ALE previously stored in address 7002 . In address 8001, a parameter SLR for selecting whether or not to permit the restart of the motor when it is judged to be abnormal in the abnormality judging process is stored in advance. The allowable upper limit number of automatic restarts RSE is stored in address 8002, and when the number of restarts performed CN exceeds RSE, restarting of the motor is not allowed, and the motor is kept stopped.

In this embodiment, it is preferable to set the SLA of address 7001 to 1, the ALE of address 7002 to 2, the SLR of address 8001 to 1, and the RSE of address 8002 to 1. When the pressure drops due to the rotation stop of the impeller due to an occasional out-of-step, the pressure drop occurs only once. At this time, the pump is restarted without issuing a fault signal, and water supply can be continued. When the discharge side pressure drops due to reasons other than out of step, such as damage to the discharge side piping, or when the pump is discharging water, multiple pressure drops occur. At this time, by outputting a failure signal, notifying the abnormality, and stopping the pump without restarting, the pump and related equipment can be protected.

However, the out-of-synchronization may occur repeatedly, such as in the case of out-of-synchronization caused by a foreign object. In such a case, as in the case of a cause other than the aforementioned out of step, the pump is not restarted more than necessary, but is stopped in order to protect the pump and related equipment.

In address 9001, when the automatic water supply device operates automatically with a constant water supply pressure, the target water supply pressure value HS is stored in advance so that the pressure detection unit 11 installed on the secondary side piping of the pump 10 can detect The speed is automatically controlled in such a way that the value is consistent with HS.

FIG. 4 shows a control flow of the first embodiment of the present invention when the pump is operated at a constant speed (constant rotation speed, constant frequency).

After the operation is started in step 101, the specified speed is reached in step 102, and the discharge side pressure value Hm at that time is stored in the volatile memory address 1010 (step 103). In step 104, selection confirmation processing of the out-of-synchronization judgment function is performed. Perform the following steps when the out-of-synchronization judgment function is selected. In step 105, in the remaining time TN1 of the timer 1 of the volatile memory address 1003, store the setting value of the cycle timer TM1 for abnormality judgment stored in advance in the nonvolatile memory address 2008, and start TN1 Count down. In step 109, if the count of timer TN1 has not ended, wait for the count of timer TN1 to end and return to step 109; if the count of timer TN1 has ended, in step 134, the current discharge side pressure Stored at address 1001 in volatile memory as HN. In step 140 it is judged whether the difference between Hm and HN is smaller than HDG stored in address 2001 in the non-volatile memory.

If the difference between Hm and HN is smaller than HDG, it is judged to be normal at step 160 , and the number of times CN of restart implementation at volatile memory address 1005 is set to 0 at step 165 . In step 181, counting of the timer is restarted, and the process returns to step 109.

When the difference between Hm and HN is greater than or equal to HDG, there is a possibility of out-of-synchronization, so it is judged to be abnormal, and the abnormal processing in step 170 is performed. After the restart processing is performed, the pump is restarted in step 180, In step 181, counting of the timer is restarted, and the process returns to step 109. In FIG. 4 , it is assumed that Hm remains unchanged, but it may be updated by copying the value of HN to the value of Hm at the time of step 181 .

As shown in Fig. 12, when a step-out occurs while the pump is operating at a constant speed, the pump loses its ability to pump water, so the pressure on the discharge side of the pump drops significantly. The extent to which the pressure drops varies depending on the suction conditions of the pump (the state of the primary side), so the judgment reference value HDG of the discharge side pressure may be determined in consideration of the suction conditions.

In the present invention, when the pressure on the discharge side of the pump drops significantly, the pump is stopped and restarted. When the normal state is not reached during the first restart and the pressure on the discharge side is lowered, the second and subsequent restarts are performed. Here, the increase rate of the command frequency indicating the rotational speed of the synchronous motor at the first restart is set to be smaller than the increase rate of the command frequency at the second and subsequent restarts. This is because when the abnormality that occurs is an occasional out-of-synchronization, it is easy to return to the normal state by gradually increasing the command frequency during the first restart. When the normal state is restored in the first restart, it can be judged that the cause of the large drop in discharge side pressure is out of step. Although not shown in the figure, information that the cause of the pressure change is out of synchronization may be output or displayed to the outside.

On the other hand, if the normal state is not restored at the first restart, there may be an abnormality caused by gas accumulation or the like. rate, repeated restarts to remove foreign matter.

In the example of Fig. 12, the increase rate of the command frequency at the time of the first restart is made smaller than the rate of increase of the command frequency at the time of the second restart, but it is also possible to make the rate of increase of the frequency at the time of the second restart smaller than that of the The rate of increase in frequency at the first restart is small. For example, even if the cause is an occasional out-of-synchronization, the normal state can be restored as soon as possible by restarting with a large frequency increase rate. After the second time, it is conceivable to preliminarily set a gentle increase rate of the command frequency in order to fail to return to the normal state in the first restart for an occasional out-of-synchronization.

FIG. 5 shows the details of the abnormal processing in step 170 . When it is judged to be abnormal in step 300 , the current number of times of restart implementation is updated in step 301 , 1 is added to the stored value of volatile memory address 1005 , and the pump is stopped in step 302 . In step 303 , the parameter SLA for selecting whether to output a failure signal stored in advance in the nonvolatile memory address 7001 is confirmed, and when SLA is set to 0, the failure signal is not output in step 306 , and the process proceeds to step 306 . In the case where SLA is set to 1, in step 304, for the abnormal detection times ALE stored in advance in the nonvolatile memory address 7002 to start outputting the fault signal and the current restart value stored in the volatile memory address 1005 The execution times CN are compared, and when CN is equal to or greater than ALE, a failure signal is output in step 305 . When CN is smaller than ALE, the failure signal is not output in step 306 and the process proceeds to step 307 .

In step 307, permission to restart is confirmed. The conditions for allowing restarting are preferably changed according to the number or frequency of restarting implementations, or the characteristics and uses of the equipment. Check the pre-stored nonvolatile memory address 8001 to select the parameter SLR to allow automatic restart. If the restart is permitted, proceed to step 308. If not, proceed to step 309 and wait for the input of a reset instruction. In step 308 , when the number of detections of the abnormality is one or less, in step 310 , the increase rate of the command frequency at restart stored in the nonvolatile memory address 1011 is set to D1. When the number of detections of the abnormality is two or more, in step 311 , the increase rate of the command frequency at the restart time stored in advance in the nonvolatile memory address 1012 is set to D2.

In addition, although it is not described in FIG. 5, it is also possible to compare the allowable upper limit number of automatic restarts RSE with the current number of restarts CN stored in the volatile memory address 1005, and manually reset the number of times RSE exceeds CN. operation to reset the indication.

When the frequency is added to the restart-allowing condition, the following condition can be added. When an abnormality is detected, the setting of the abnormality frequency confirmation timer TM2 stored in the non-volatile memory address 2009 in advance is sufficient. The fixed value is stored in the remaining time TN2 of timer 2 at address 1004 of the volatile memory, so that TN2 counts down. When an abnormality is detected again before TN2 becomes 0, restarting is not allowed. For example, if TN2 is set to 1 hour, if an abnormality is detected twice within 1 hour, it can be presumed that the cause is not an accidental out-of-synchronization but an external cause.

FIG. 6 shows the control flow of the present invention when the automatic water supply device operates automatically so that the water supply pressure is constant.

When a decrease in the discharge side pressure is detected in step 100 , after the operation is started in step 101 , a predetermined speed is reached in step 102 . In step 104, selection confirmation processing of the out-of-synchronization judgment function is performed. When it is confirmed that the out-of-synchronization judging function is selected, it is judged in step 130 whether the current discharge side pressure is higher than the target pressure HS stored in advance in address 9001 of the nonvolatile memory. When the current discharge side pressure is higher than the target pressure HS, a deceleration instruction is performed in step 131 . When deceleration is instructed, the output frequency is changed in step 132 . On the contrary, when the current discharge side pressure is lower than the target pressure HS, an acceleration instruction is given in step 133 . When acceleration is instructed, the output frequency is changed in step 135 .

Then, in step 105, the setting value of the cycle timer TM1 for out-of-synchronization judgment stored in advance in the nonvolatile memory address 2008 is stored in the timer 1 remaining time TN1 of the volatile memory address 1003, and the start Countdown of TN1. After confirming that the countdown of TN1 is completed in step 109 , the current discharge side pressure HN is saved in step 134 , and it is judged in step 142 whether the difference between HN and target pressure HS is smaller than HDG.

If the difference between the discharge side pressures HN and HS is smaller than HDG, it is judged to be normal at step 160 , and the number of restart execution times CN at the volatile memory address 1005 is set to 0 at step 165 . Then return to step 130 .

If the difference between the discharge side pressure and HS is greater than or equal to HDG, it is judged that there is a possibility of out-of-synchronization, and the abnormal processing in step 170 is performed, and after the restart processing is performed, the pump is restarted in step 180, and the process returns to step 130 .

The abnormality processing in step 170 is the same control flow ( FIG. 5 ) as in the case of operating the pump at a constant speed (constant rotational speed, constant frequency), and thus description thereof will be omitted.

In a second embodiment of the present invention, in a synchronous motor driving a pump, out-of-synchronization is detected from a change in pump secondary side pressure and a change in load current value.

When the pressure on the secondary side of the pump decreases and the pump load current value does not exceed a certain value, it is determined that there is a possibility of out-of-step, and the normal operation is restarted by restarting the motor. The structure is the same as that of the first embodiment, and is the structure shown in Fig. 1 and Fig. 2 .

The contents of the volatile memory and the contents of the nonvolatile memory stored in the storage unit are shown in FIG. 3 . The contents of the memory are the same as those in the first embodiment, but in this embodiment, the load current value AN on the secondary side of the pump when the out-of-synchronization judgment starts is recorded in address 1002 .

FIG. 7 shows a control flow of the present embodiment when the pump is driven at a constant speed (constant rotation speed, constant frequency).

Start operation in step 101 . After reaching the specified speed in step 102, the initial discharge side pressure Hm is stored in address 1010 of the volatile memory in step 103. In step 104, selection confirmation processing of the out-of-synchronization judgment function is performed. When the out-of-synchronization judging function is selected, the counting of the timer is started in step 105 . It is confirmed in step 109 that the timer has counted up, and in step 106 the current discharge side pressure is stored in the volatile memory address 1001 as HN. Furthermore, in step 107 , the current load current value is stored as AN in the volatile memory address 1002 .

As shown in FIG. 13 , even in the out-of-step state, a current corresponding to the induced voltage flows through the motor, and a current substantially equal to the value in the normal rotation state flows. When out-of-step occurs, the pump loses its ability to pump water, so the pressure on the discharge side of the pump is greatly reduced, but the load current value does not change significantly.

A general pump characteristic is shown in FIG. 14 . When operating at an arbitrary frequency HzN, the discharge side pressure is Ha and the load current value is Aa at the discharge flow rate Qa. Here, when the discharge flow rate increases from Qa to Qb, the discharge side pressure decreases to Hb, and the load current value increases to Ab. It can be seen that when the discharge side pressure decreases, the load current value increases.

Therefore, in step 143, when HN-Hm is HDG or more, it judges as normal in step 160, and returns to step 105.

When HN-Hm is smaller than HDG, it is judged in step 144 whether the current load current value is greater than AN+ADG, and in the case of greater than AN+ADG, it is judged as normal in step 161 , and the process returns to step 105 .

If it is less than AN+ADG, it is judged as out-of-synchronization, and the abnormal time processing of step 170 is performed, and after the restart processing is performed, the pump is restarted in step 180 , and the process returns to step 105 . In the state of FIG. 13 , by detecting out-of-synchronization as soon as possible and restarting as soon as possible, the normal state can be restored before the pressure drops significantly. Accordingly, the influence of the out-of-synchronization on the water supply can be minimized. The abnormal processing in step 170 is the same as that in the first embodiment, as shown in FIG. 5 .

FIG. 8 shows the control flow of the present invention when the automatic water supply device operates automatically so that the water supply pressure is constant.

When a decrease in the discharge side pressure is detected in step 100 , the operation is started in step 101 . After the specified speed is reached in step 103 , in step 104 , the process of selecting and confirming the out-of-synchronization judging function is performed. After the selection confirmation process of the out-of-synchronization judging function, the current load current value is stored in the volatile memory address 1002 as AN in step 107 . In step 130 it is judged whether or not the discharge side pressure is higher than the target pressure HS prestored in address 9001 of the nonvolatile memory. When the discharge side pressure is higher than the target pressure HS, a deceleration instruction is given in step 131 . When deceleration is instructed, the output frequency is changed in step 132 . Conversely, when the discharge side pressure is lower than the target pressure HS, an acceleration instruction is given in step 133 . When an acceleration instruction is given, the current discharge side pressure is stored in the volatile memory address 1001 as HN in step 134 , and then the output frequency is changed in step 135 .

When the instructed speed has been reached, the process proceeds to step 143 . Hereinafter, steps after step 143 are the same control flow as in the case of operating the pump at a constant speed (constant rotation speed, constant frequency) ( FIG. 7 ), and thus description thereof will be omitted.

In the second embodiment, by combining the discharge side pressure and the load current value, it is possible to more accurately detect out-of-synchronization.

Next, a third embodiment of the present invention will be described. In the third embodiment, the characteristic data of the pump is stored in the memory unit, and the discharge side pressure at the operating frequency (command frequency) during pump operation, or the load current value is compared with the value calculated based on the characteristic data. Detect out of sync.

When the difference between the discharge side pressure calculated based on the characteristic data of the pump and the detected discharge side pressure, or the load current value calculated based on the characteristic data of the pump and the detected load current value exceeds the judgment reference value, it is judged as In case of abnormality, normal operation is restarted by restarting the motor.

First, the structure is the same as that of the first embodiment, and is the structure shown in FIGS. 1 and 2 . The contents of the volatile memory and the contents of the nonvolatile memory stored in the storage unit are shown in FIG. 3 .

The calculated discharge side pressure HC obtained by the pump characteristic calculation process is stored in address 1006 of the volatile memory. Similarly, the calculated load current value AC obtained by the pump characteristic calculation process is stored in address 1007 . The calculated flow rate QC obtained by the pump characteristic calculation process is stored at address 1008 . The address 1009 stores the result of judging whether or not the difference between the result obtained by the pump characteristic calculation processing and the actual detection value is within the judgment reference value. When the calculated value matches the detected value, 0 is stored, and when the calculated value does not match the detected value, 1 is stored.

Pump characteristic data are recorded in address 3100 to address 3215 of the nonvolatile memory. Store in non-volatile memory in advance the lift (recorded in address 3100), flow rate (recorded in address 3101), flow rate (recorded in address 3101) and Current (recorded in address 3102), lift at measuring point 2 (recorded in address 3103), flow rate (recorded in address 3104), current (recorded in address 3105), and also store measuring point 3 and measuring point 4 Head, flow rate, current at measuring point 5 (recorded in address 3112), flow rate (recorded in address 3113), current (recorded in address 3114). The relationship of the pump characteristic data stored in address 3100 to address 3215 is shown graphically as shown in FIG. 15 .

The pump characteristic data can also be one group, but in the pump characteristic calculation process, it is better that the current frequency is close to the frequency of the pre-recorded pump characteristic data, so the measurement points 1 to 5 at other frequencies (recorded in address 3215) are stored The head, flow and current at the place are better. There may be no more than two frequencies, and it is better to save more than three frequencies and their corresponding data.

The contents of the other volatile memory and nonvolatile memory used are the same as those in the first and second embodiments, and thus description thereof will be omitted.

FIG. 9 shows the control flow of the present invention when the automatic water supply device operates automatically so that the water supply pressure is constant.

When a decrease in the discharge side pressure is detected in step 100 , the operation is started in step 101 . After the specified speed is reached in step 103 , in step 104 , the process of selecting and confirming the out-of-synchronization judging function is performed. After that, it is judged in step 130 whether the discharge side pressure is higher than the target pressure HS stored in advance in address 9001 of the nonvolatile memory. When the discharge side pressure is higher than the target pressure HS, a deceleration instruction is given in step 131 . When deceleration is instructed, the output frequency is changed in step 132 . Conversely, when the discharge side pressure is lower than the target pressure HS, an acceleration instruction is given in step 133 . When acceleration is instructed, the output frequency is changed in step 135 .

After the current discharge side pressure is stored as HN in the volatile memory address 1001 in step 151 , the current load current value is stored in the volatile memory 1002 as AN in step 152 . After the current command frequency is stored in the volatile memory address 1000 as HzN in step 153 , pump characteristic calculation processing is performed in step 154 .

In step 155, it is judged whether the current output (detection value) matches the calculation result (calculation value). When they match (when the value CS stored in the volatile memory address 1009 is 0), it is judged to be normal in step 160 , and the process returns to step 103 . In the case where the current output (detection value) does not match the calculation result (calculation value) (CS is 1), it is judged to be out of synchronization, and the abnormal processing in step 170 is performed. After restart processing, in step 180 Restart the pump and return to step 103.

The abnormal processing in step 170 is the same as above, so the description is omitted.

The details of the pump characteristic calculation processing in step 154 are shown in FIG. 10 (example 1).

In step 400 HzN is read from volatile memory address 1000 , HN is read from address 1001 , and AN is read from address 1002 .

In step 401 , based on HzN and the characteristic data pre-recorded in addresses 3100 to 3215 of the non-volatile memory, the pump characteristic curve at the current command frequency HzN is calculated, and the details will be described later.

In step 411 , the current flow rate QC is calculated based on the calculated pump characteristic curve and the current discharge-side pressure HN. In step 412 , based on the calculated flow rate QC and the current command frequency HzN, the calculated load current value AC at the flow rate QC is obtained. In step 413, it is confirmed whether the difference between the current load current value AN and the calculated load current value AC is smaller than ADG stored in advance in the non-volatile memory address 2002, and if the difference between AN and AC is within ADG, then In step 431 , it is considered that the current output agrees with the calculation result, and 0 is stored in the comparison CS with the calculation result at address 1009 of the volatile memory. When the difference between AN and AC exceeds ADG, it is considered that the current output does not agree with the calculation result in step 432, and 1 is stored in CS. After the process is completed, proceed to step 155 .

Another example (example 2) of the pump characteristic calculation process in step 154 is shown in FIG. 11 .

In FIG. 10 (Example 1), the flow rate QC is calculated based on the discharge side pressure in step 411, the load current value AC is calculated in step 412, and the current load current value AN is compared with the calculated load current value AC in step 413. .

In contrast, in FIG. 11 (Example 2), the flow rate QC is calculated based on the load current value in step 421, the discharge pressure HC is calculated in step 422, and the current discharge pressure HN and the calculated discharge pressure are compared in step 413. Pressure HC for comparison.

The pump characteristic calculation processing will be further described in detail. The current pump operating state is calculated based on the flow rate and discharge side pressure at each frequency, the load current value and the current discharge side pressure HN or load current value AN pre-recorded in the storage unit.

First, it is checked whether there is pump characteristic data at a frequency that matches the current command frequency HzN. If not, the pump performance is approximated based on the performance data at the frequency closest to the command frequency HzN (corresponding to step 400 in FIG. 10 or FIG. 11 ). The pump performance is relative to the frequency, the flow rate is proportional to a linear function, the discharge side pressure is proportional to a quadratic function, and the current value is proportional to a cubic function. In this way, the pump characteristic data during operation at the current command frequency HzN is calculated based on the pump characteristic data of the pre-stored frequency close to the command frequency HzN using the law of similarity.

First, calculate the coefficients FC1, FC2, and FC3 used in the calculation of the similarity law according to Equation 1, Equation 2, and Equation 3 as follows:

FC1=(F1÷FC)...Formula 1

FC2＝(F1÷FC) ² ......Formula 2

FC3＝(F1÷FC) ³ ......Formula 3

For example, if the frequency data closest to the current command frequency HzN is Hz1 recorded in address 3115, then for the head-related performance data H11, H12, H13, H14, H15 measured at frequency Hz1 (record Addresses 3100, 3103, ..., 3112) are multiplied by FC1 to obtain HC1, HC2, HC3, HC4, and HC5. Similarly, the flow-related performance data Q11, Q12, Q13, Q14, Q15 (recorded in addresses 3101, 3104, ..., 3113) are respectively multiplied by FC2 to obtain QC1, QC2, QC3, QC4, QC5. Furthermore, current-related performance data A11, A12, A13, A14, A15 (recorded in addresses 3102, 3105, ..., 3114) are multiplied by FC3 respectively to obtain AC1, AC2, AC3, AC4, AC5.

The approximation is obtained, for example, by Newton's interpolation method or Lagrange interpolation polynomial. In the case of using Newton's interpolation method, the characteristic curve of the discharge side pressure with respect to the discharge flow rate: QH curve (Hi(Qi)) is:

C0=HC1

C1＝(HC2-HC1)÷(QC2-QC1)

C2'＝(HC3-HC1)÷(QC3-QC1)

C2＝(C2'-HC2)÷(QC3-QC2)

C3"＝(HC4-HC1)÷(QC4-QC1)

C3’＝(C3”-HC2)÷(QC4-QC2)

C3＝(C3'-HC3)÷(QC4-QC3)

C4"'＝(HC5-HC1)÷(QC5-QC1)

C4”=(C4”’-HC2)÷(QC5-QC2)

C4’＝(C4”-HC3)÷(QC5-QC3)

When C4＝(C4’–HC4)÷(QC5-QC4),

can be obtained as follows:

Hi(Qi)

=C0

+C1×(Qi-QC1)

+C2×(Qi-QC1)×(Qi-QN2)

+C3×(Qi-QC1)×(Qi-QN2)×(Qi-QC3)

+C4×(Qi-QC1)×(Qi-QC2)×(Qi-QC3)×(Qi-QC4)

...Formula 4

Similarly, let the characteristic curve of the load current value relative to the discharge flow rate: QA curve (Ai(Qi)) be:

C5=AC1

C6＝(AC2-AC1)÷(QC2-QC1)

C7'＝(AC3-AC1)÷(QC3-QC1)

C7＝(C7'-AC2)÷(QC3-QC2)

C8"＝(AC4-AC1)÷(QC4-QC1)

C8’＝(C8”-AC2)÷(QC4-QC2)

C8＝(C8'-AC3)÷(QC4-QC3)

C9"'＝(AC5-AC1)÷(QC5-QC1)

C9”=(C9”’-AC2)÷(QC5-QC2)

C9’＝(C9”-AC3)÷(QC5-QC3)

When C9=(C9'-AC4)÷(QC5-QC4),

can be obtained as follows:

Ai(Qi)

=C5

+C6×(Qi-QC1)

+C7×(Qi-QC1)×(Qi-QN2)

+C8×(Qi-QC1)×(Qi-QN2)×(Qi-QC3)

+C9×(Qi-QC1)×(Qi-QC2)×(Qi-QC3)×(Qi-QC4)

...Formula 5

(Equation 4 corresponds to step 401 in FIG. 10, and Equation 5 corresponds to step 401 in FIG. 11). Figure 16 shows the QH curve (Hi(Qi)) and QA curve (Ai(Qi)) graphically.

It is difficult to solve the quartic equation. Therefore, for example, by using the substitution method, the flow rate QC (corresponding to step 421 in FIG. 11 ) is obtained according to Equation 5 when the load current value is AC at the command frequency HzN (corresponding to step 421 in FIG. 11 ). 4. Obtain the discharge side pressure HC when the flow rate is QC at the command frequency HzN (corresponds to step 422 in FIG. 11 ).

In this way, the QH curve and QA curve are obtained by approximation based on the pump characteristic data closest to the command frequency HzN, so it is preferable that there are approximately five points of pump characteristic data measured and stored in advance for each frequency.

As mentioned above, the frequency of the pre-measured and stored pump characteristic data can also be one, but because the QH curve and the QA curve are not completely consistent with the similarity law of the pump, by saving the characteristic data at multiple operating frequencies, from the characteristic Select the data closest to the current operating frequency among the data, and perform the above-mentioned characteristic data calculation processing, so that the QH curve and QA curve can be obtained more accurately, and as a result, the current pump operating state can be accurately grasped.

The first and second embodiments are simple because they do not need to store pump characteristic data in advance, and are not affected by changes in pump characteristics due to aging deterioration because out-of-step judgments are made based on changes during operation. It is excellent in one point, but in the third embodiment, by comparing the previously measured and stored pump characteristic data with the actual operating state as described above, it is possible to accurately detect an abnormality in a short time. superior.

Claims (8)

1. a kind of pumping system, it includes：

Pumping section, it has the impeller being arranged in pump case body；

Synchronous motor, it drives the impeller rotation；With

Inverter, its described synchronous motor of control,

The pumping system is characterised by：

The inverter includes：

Signal input unit, pressure sensing cell for detect hydraulic pressure of its input from the discharge side for being arranged at the pumping section Signal；

Operation processing unit, it determines the rotating speed of the synchronous motor；

Memory element, its control parameter of storage by required for the computing that the operation processing unit is carried out；With

Power conversion unit, it supplies driving current to the synchronous motor,

The operation processing unit, becomes in basis from the pressure that the signal detection of the pressure sensing cell goes out more than setting During change, enter to exercise the process that the synchronous motor stops, resetting, the synchronous motor described in resetting for the first time In the case of non-normal starting, the increment rate with the rotating speed of synchronous motor when resetting from the first time is different Increment rate is reset for the second time.

2. pumping system as claimed in claim 1, it is characterised in that：

The operation processing unit, the pressure change of more than setting is detected the synchronous motor is reset Afterwards, in the case that the detected value of pressure sensing cell reverts to normal range in first time resets, by pressure change The reason for be judged as step-out and the signal of step-out represented to outside output.

3. pumping system as claimed in claim 1, it is characterised in that：

The operation processing unit, basis from the signal detection of the pressure sensing cell go out reduced pressure setting with When upper and load current value is below setting, enter to exercise the process that the synchronous motor stops, resetting, the In the case of the non-normal starting of synchronous motor described in once resetting, with described same when resetting with the first time The increment rate that the increment rate of the rotating speed of step motor is different is reset for the second time.

4. pumping system as claimed in claim 1, it is characterised in that：

In the case where the number of times reset has exceeded stipulated number, the operation processing unit exports fault-signal.

5. pumping system as claimed in claim 1, it is characterised in that：

The institute when increment rate of the rotating speed of the synchronous motor when first time resets is than resetting for the second time The increment rate for stating the rotating speed of synchronous motor is little.

6. a kind of pumping system, it includes：

Pumping section, it has the impeller being arranged in pump case body；

Synchronous motor, it drives the impeller rotation；With

Inverter, its described synchronous motor of control,

The pumping system is characterised by：

The inverter includes：

Signal input unit, pressure sensing cell for detect hydraulic pressure of its input from the discharge side for being arranged at the pumping section Signal；

Operation processing unit, it determines the rotating speed of the synchronous motor；

Memory element, its control parameter of storage by required for the computing that the operation processing unit is carried out；With

Power conversion unit, it supplies driving current to the synchronous motor,

In the memory element, the discharge lateral pressure being previously stored with the rotating speed of multiple synchronous motors, the rotating speed Relative to delivery flow characteristic and load current value relative to delivery flow characteristic,

The operation processing unit, in actual rotating speed, discharges the relation of lateral pressure and load current value departing from being stored in In the case of stating the characteristic in memory element, enter to exercise the process that the synchronous motor stops, resetting, in first time weight It is new start described in the case of the non-normal starting of synchronous motor, with described synchronous electronic when resetting with the first time The increment rate that the increment rate of the rotating speed of machine is different is reset for the second time.

7. pumping system as claimed in claim 6, it is characterised in that：

In the case where the number of times reset exceedes stipulated number, the operation processing unit exports fault-signal.

8. pumping system as claimed in claim 6, it is characterised in that：

The institute when increment rate of the rotating speed of the synchronous motor when first time resets is than resetting for the second time The increment rate for stating the rotating speed of synchronous motor is little.