JPS5994114A - Pump controller - Google Patents

Abstract

PURPOSE:To shorten the operation time with simple constitution, by preserving the flow rate of a pump, the rotation number of the pump obtained on the basis of the pressure characteristic, and the flow rate characteristic as internal data of an operating device and controlling the rotation number of the pump on the basis of these values and the signal of an actual discharge flow rate. CONSTITUTION:A forecast pump discharge flow rate Q' for a certain target water level H0 is obtained in accordance with a pump characteristic diagram, and the relation between this forecast pump discharge flow rate Q' and a pump rotation number N is patterned and is stored in an operating device 20. It is assumed that the discharge flow rate of a pump 5 detected by a sensor 9 is Q0 at a certain sampling time and the rotation number of the pump 5 is N0 then and a forecast discharge flow rate for a pump rotation number N0 at the time of the target water level H0 is Q', the device 20 calculates a deviation DELTAQ between the actual discharge flow rate Q0 and the discharge flow rate from a table where it is stored preliminarily and uses this deviation DELTAQ to perform proportional and integral operations, thus obtaining a pump rotation number controlling command value.

Description

[Detailed description of the invention] The present invention relates to a sewer pump control device.

Figure 1 shows an overview of a control device in a conventional sewage pumping station, where 1 is a sewage pipe, 2 is a settling basin, and 3 is a pump well. It is pumped up and discharged to the discharge valve 6. At that time, the outflow amount adjustment is performed using the inflow channel water level signal detected by the water level sensor 7 installed near the inflow prefecture or the detection signal detected by the water level sensor 8 installed in the pump well 3. 10
The predicted (target) discharge flow rate is calculated by performing various calculations from this water level signal and each of these signals, and the difference between this predicted discharge flow rate and the actual discharge flow rate (No. 1PID calculation is performed, and the value obtained by this calculation is used as a new rotational speed output command for the pump 5, and by increasing or decreasing the rotational speed of the pump 50 in response to this command, the entire flow rate is controlled and the pump is operated in an optimal manner.

However, in the case of this kind of conventional control method, although the control accuracy is good, it requires the input of at least three signals, so the circuit configuration including the sensor is complicated p1. (generally, an electronic computer is used as the arithmetic unit), and the control method has also become relatively complex. This invention was made in view of this point, and its purpose is to hold the pump N rotation number-flow wrinkle characteristic determined from the Q-H characteristic of the pump as internal data of the calculation device, and to combine this value with the actual discharge. It is an object of the present invention to provide this sleeve control device which is simple and requires short calculation time by controlling the rotational speed of the pump using only a flow rate signal.

An embodiment of the present invention will be described below based on the drawings. In Figure 2, the same symbols as in Figure 1 indicate the same or equivalent parts. In other words, the sensor 7.8 shown in FIG. 1 is removed from the one shown in FIG. FIG. 3 is a characteristic diagram showing the relationship between the Q-H characteristic determined by the pump and the resistance characteristic of the discharge pipe, with pressure H on the vertical axis and flow iLQ on the horizontal axis, and the present invention consists of this pump characteristic diagram. The expected pump discharge flow rate Q"fir at the target water level Ho is calculated, and as shown in Fig. 4, this expected pump discharge flow tQ' and the pump rotation speed N
The relationship is patterned as a diagram and stored in the arithmetic device. Now, the discharge flow rate of the pump 5 detected by the sensor 9 is QO at a certain sampling time, and the rotation speed of the pump 5 at that time is N.

Suppose it was. Further, the expected discharge amount when the pump rotation speed is No at the target water level Ho is assumed to be Q'.

The calculation device side calculates the actual discharge amount Q detected by the sensor 9.
o and Q′ from the table stored in advance.
Pull out QO! Calculate the deviation ΔQ from =Q',
The deviation Δct' is used to calculate the PI leakage according to the following equation, and the calculated value is used as the pump rotation speed control command.

MVn=MVn-10K ('n 'n-1)0Ki
・a n・Δ where MV is operation i (rotation speed output command value)
, K is the deviation (=ΔQ), n is the sampling point n, and n-
1 is the time one point before time n, K is a proportional constant, Ki is an integral constant, and Δt is the sampling period. In the figure, reference numeral 21 denotes a first memory section in which the deviation 1n-t at the sampling point immediately before the current deviation 6n is stored. 22 is a subtraction unit that subtracts εn-'n-1, and the resultant value is multiplied by a proportionality constant K in a first multiplication unit 23. In the second multiplication section, the current deviation 8n is multiplied by the integral constant 1 and the sampling period signal Δt. The section is a second memory section, which stores the operation i''Vn-1 at the time of the previous sampling.The base is an addition section, in which each of the above-mentioned signals is added to obtain the rotation speed output command value of the pump 5. is determined, and the rotation speed of the pump is controlled based on this value.

As described above, in the present invention, Q determined by the pump,
- The pump rotation speed N and flow rate Q characteristic determined from the H% characteristics are stored as data in a calculation device, and the pump rotation speed is controlled only by these values and the signal of the pump's actual discharge flow itQo. I'll go.

Therefore, according to the present invention, the input signal to the arithmetic unit is only one pump discharge flow rate, which simplifies the circuit, and there is no need to perform calculations from water level signals to flow rate conversion as in the past, and it is simply carried internally. Since it is only necessary to compare the existing data, it has excellent advantages such as shortening calculation time.

[Brief explanation of the drawing]

Fig. 1 shows the & origins of a conventional pump control device, Fig. 2 is a configuration diagram showing an embodiment of the present invention, and Fig. 3 shows the Q-H% of the pump.
Fig. 4 is a flow rate-rotational speed characteristic diagram of the pump determined from the Q-H% property shown in Fig. 3, and Fig. 5 is a functional configuration diagram of the present invention. 2 is a settling basin, 3 is a pump well, 5 is a pump, addition is an arithmetic unit, 21.25 is a memory section, 22 is a subtraction section, and B. 24 is a multiplication section, and station is an addition section.

Claims (1)

[Claims] In a device in which the rotation speed of a pump installed in a pump well is controlled by a command value of a calculation device Q, the rotation speed-flow rate characteristic of the pump is determined from the flow rate-pressure characteristic of the pump, and the rotation speed-flow rate characteristic is determined by the calculation device. A storage means for storing the expected discharge flow rate, a means for detecting the actual discharge flow rate of the pump and calculating a deviation value from the expected discharge flow rate are provided, and a means for storing the previous operation amount and a value one sampling before the current deviation value is provided. A pump characterized in that it comprises means for subtracting and multiplying by a proportionality constant, and means for adding values obtained by multiplying the current deviation value by an integral constant and a sampling period signal. Control device.