JP2000009046A - Variable speed pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable speed pump device in which both a noise of a motor and heat generation of the motor can be reduced. SOLUTION: This variable speed pump has an inverter control means 21b, an automatic startup/stop control means 21c, and a carrier frequency control means 21c. The inverter control means 21b controls an operation frequency of an electric motor which drives the pump. The automatic startup/stop control means 21c calculates the operation frequency of the pump according to an operation state of the pump, and outputs the calculated operation frequency to the inverter control means 21b, while the automatic startup/stop control means 21c automatically performs startup and stop of the pump. The carrier frequency control means 21c increases or decreases a carrier frequency to be outputted to the inverter control means 21b according to the magnitude of the operation frequency of the pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable speed pump device for starting and stopping a water supply pump connected between a water source and a water demand source, and controlling the rotation speed.

[0002]

2. Description of the Related Art A water supply pump is connected between a water source and a water demand source to control the number of revolutions of the pump in accordance with the demand state of the water demand source or the operation state of a start switch, or to start and stop the pump. 2. Description of the Related Art A variable-speed pump device that performs an operation is known.

In such a variable speed pump device, an inverter for controlling an operation frequency of a feed water pump is provided with a function of controlling the rotation speed of the pump and a function of automatically starting and stopping the pump. 6-76
No. 665 is known.

According to the technique of this publication, the speed signal f is controlled so that the pressure H of the water supply pipe 5 approaches the target pressure Htar during the operation of the pump. Here, the speed signal f represents the percentage at which the pump is operating at the rated frequency. For example, when the pump is operating at the rated frequency, the speed signal f is 100%, and when the pump is operating at 70% of the rated frequency, the speed signal f is 70%.
%.

That is, it is determined whether the pressure signal H of the water supply pipe 5 is higher than the target pressure Htar, and if "H>Htar", the speed signal f is controlled so as to decrease the output frequency of the inverter 21 and "H" If <Htar ”, the speed signal f is controlled so as to increase the output frequency of the inverter 21. In this way, during the operation of the pump 2, when the use of customer water decreases, the output frequency of the inverter 21 also decreases. Conversely, when the use of customer water increases, the output frequency of the inverter 21 also increases. The required water supply is also ensured.

[0006]

As described above, conventionally, the number of pulses per unit time supplied to the motor 11 for driving the pump 2 is increased or decreased according to the output frequency of the inverter 21. For example, if the number of pulses per unit time output from the inverter 21 to the motor 11 is equal to or more than 10,000, the main frequency component of the noise generated from the motor 11 is not less than tens of kHz, that is, not less than the audible range. The operating noise of the motor 11 is a quiet operating noise.

However, when the number of pulses per unit time is 10,000 or more, heat generation due to ON / OFF loss greatly increases in each switching in proportion to the number of switching, so that energy saving operation is performed. It was getting harder to do.

In order to reduce the heat loss, the motor 11 must be cooled by a large cooling fan. Therefore, the cost for cooling has increased.

Conversely, if the number of pulses per unit time output from the inverter 21 to the motor 11 is less than 10,000, the frequency component of the noise generated from the motor 11 is less than tens of kHz, that is, in the audible range. Motor 1
There is a problem in that the driving noise increases due to an increase in the driving noise of No. 1.

That is, conventionally, the noise from the motor 11 increases when the heat from the motor 11 is reduced, and the heat from the motor 11 increases when the noise from the motor 11 is reduced. There was a problem.

The present invention has been made in view of the above points, and an object of the present invention is to provide a variable speed pump device which can reduce both noise from a motor and heat generation from a motor. is there.

[0012]

According to a first aspect of the present invention, there is provided a variable speed pump device, comprising: an inverter control means for controlling an operation frequency of an electric motor for driving the variable speed pump; Calculating and outputting the frequency to the inverter control means, and automatic start / stop control means for automatically starting and stopping the variable speed pump;
And a carrier frequency control means for increasing or decreasing the carrier frequency output to the inverter control means in accordance with the magnitude of the operating frequency of the pump.

According to a second aspect of the present invention, there is provided a variable speed pump device for controlling an operation frequency of an electric motor for driving the variable speed pump, and calculating an operation frequency of the pump according to an operation state of the pump. Automatic start / stop control means for automatically starting and stopping the variable speed pump while outputting to the inverter control means, and increasing or decreasing the carrier frequency output to the inverter control means according to the ambient temperature of the inverter control means. And carrier frequency control means.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a variable speed pump device according to an embodiment of the present invention. FIG.
In the figure, reference numeral 1 denotes a motor for driving a feed pump 2 which is a variable speed pump. A suction pipe 3 is connected to a suction port of the water supply pump 2, and a discharge port thereof is connected to a faucet (not shown) of each household via a water supply pipe 5 provided with a flow rate sensor 4.

A pressure sensor 6 for detecting the pressure of a water supply pipe 5 is provided in a pipe between the discharge port of the pump 2 and the flow sensor 4.
Are arranged. Further, a pressure tank 7 is disposed immediately downstream of the flow sensor 4 in the water supply pipe 5.

By the way, the flow sensor 4 outputs a flow signal Q which becomes an off signal when the flow rate flowing through the water supply pipe 5 becomes equal to or less than the minimum flow rate Qmin and becomes an on signal when the flow rate becomes larger than the minimum flow rate Qmin.

The pressure sensor 6 detects the pressure of the water supply pipe in an analog manner, and outputs an analog pressure signal H. By the way, the inverter 21 receives a signal from the main circuit 21b as an inverter control means, a first control circuit 21a for controlling the main circuit 21b, a flow sensor 4, a pressure sensor 6, and a start switch 15 to receive a first signal. Control circuit 21a
And a second control circuit 21c that outputs a start signal s, a frequency signal f, and a carrier frequency fc.
The second control circuit 21c includes automatic start / stop control means and carrier frequency control means.

A flow signal Q output from the flow sensor 4 is taken into a CPU (central processing unit) 42 through an input port 43a of the inverter 21. Further, the pressure signal H output from the pressure sensor 6 is converted into a digital pressure signal via an A / D (analog / digital) converter 44 in the inverter 21 and then taken into the CPU 42.

Further, the input port 4 is connected to the inverter 21.
3b, an ON / OFF signal of the start switch 15 for instructing the water supply pump 2 to automatically operate is supplied to an input port 43b.
Via the CPU 42. The CPU 42 has a carrier frequency switching program as a carrier frequency control unit for switching the carrier frequency shown in the flowchart of FIG. 2, an automatic pump start / stop control program as an automatic start / stop control unit shown in the flowchart of FIG.
Is connected to a memory 46 for storing a pump speed control program and various flags shown in the flowchart of FIG.

Further, a communication I / F (interface) 47 is connected to the CPU 42. The communication I / F 47 is a communication I / F connected to the CPU 22 of the first control circuit 21a.
Connected to F51. Communication I / F 47 and Communication I / F
The start signal S, the speed signal f, and the carrier frequency signal fc are serially transmitted between 51.

Here, the speed signal f designates at what percentage of the rated frequency the motor 1 is driven by f. For example, when the motor 1 is driven at the rated frequency, 100% is output as the speed signal f. When the motor 1 is driven at 75% of the rated frequency, 75% is output as the speed signal f.
% Is output.

The CPU 22 of the first control circuit 21a is a memory 2 in which a program for performing inverter control is stored.
6. The driver 27 is connected. Further, a driver 27 is connected to the CPU 22. This driver 27
An on / off signal is output to the main circuit 21b via the.
That is, in the main circuit 21b, the AC power supply is rectified through the rectifier 31 and the capacitor 32 and connected to the collector of the power transistor 33. The base of the AC power supply receives the on / off signal from the driver 27. Has been entered. The emitter of the power transistor 33 is connected to the motor 1. That is, the inverter 21 outputs power of a frequency corresponding to the input speed signal f to the motor 1 via the power transistor 33.

When the power transistor 33 is turned on / off at a high speed, an approximate sine waveform as shown by a solid line in FIG. 8 is output. When the period T is changed, the frequency of the output power output from the power transistor 33 changes, and when the pulse width W is changed, the power transistor 33 changes.
The effective voltage value of the output power changes.

Next, the operation of the embodiment of the present invention configured as described above will be described with reference to the flowcharts of FIGS. First, the CPU 42 sets the input port
The on / off state of the start switch 15 input through the switch 23b 'is determined, that is, whether the start switch 15 is on (step S1). In this determination, if the start switch 15 is off, the start signal S is output as "0" via the communication I / F 47, and a process of stopping the pump 2 is performed (step S2).

On the other hand, if it is determined in step S1 that the start switch 15 is ON, the automatic start / stop control is executed as shown in FIG. Hereinafter, the automatic start / stop control will be described with reference to the flowchart of FIG. First, it is determined whether the pump 2 is operating with reference to the operation flag set in the memory 26 (step S11). “YES” in the determination of this step S11,
If it is determined that the pump 2 is operating, the flow sensor 4
Is the minimum flow Qmi flowing through the water supply pipe 5 detected by
It is determined whether it is equal to or less than n (step S12). Here, as described in the configuration, the flow rate sensor 4 outputs an off signal when the flow rate flowing through the water supply pipe 5 becomes equal to or less than the minimum flow rate Qmin, so that the CPU 42 sets the input port 43a '.
It is determined whether or not the off signal is input to the. And when it determines with "YES" in the determination of step S12, it determines that the use of the water of the customer has decreased, and performs the process of stopping the pump 2 (step S13).

By the way, in step S11 described above, "N
O ", that is, when it is determined that the pump is stopped, it is determined whether the pressure signal H is equal to or lower than a predetermined pressure Hmin (step S14). While pump 2 is stopped,
Water is supplied by the pressure tank 7. However, if water is supplied while the pump 2 is stopped, the pressure of the water supply pipe 5 may decrease, and the pressure signal H may become lower than the predetermined pressure Hmin.

When determining that "H≤Hmin", the CPU 12 outputs a start signal S for starting the pump 2 (step S15). At this time, since the operation flag is set, when the determination of step S11 is reached again, “Y
ES ”and proceeds to the determination of step S12. As long as the flow rate flowing through the water supply pipe 5 is larger than the minimum flow rate Qmin (that is,“ NO ”in step S12), the pressure of the water supply pipe 5 during the pump operation is increased. The speed signal f of the inverter 21 is controlled so that H approaches the target pressure Htar.

That is, it is determined whether the pressure signal H of the water supply pipe 5 is higher than the target pressure Htar (step S16).
If> Htar, the on / off signal output from the driver 27 to the power transistor 33 is variably controlled so as to reduce the speed signal f of the inverter 21, and "H <Htar".
If so, the on / off signal output from the driver 27 to the power transistor 33 is variably controlled so as to increase the speed signal f of the inverter 21. In this way, during the operation of the pump 2, when the use of water at the customer decreases, the output frequency of the inverter 21 also decreases. Conversely, when the use of water at the customer increases, the frequency of the inverter 21 increases. The output frequency is also increased to secure the required water supply.

The speed signal f calculated in the flowchart of FIG. 4 is determined by a carrier frequency switching program stored in the memory 46, and the carrier frequency signal fc is switched according to the speed signal f.

That is, it is determined whether or not the speed signal f is greater than 75% (step S21). This step S2
If it is determined to be "YES" in the determination of Step 1, 1 kHz is set as the carrier frequency signal f (Step S).
22).

On the other hand, if the determination in step S21 is "NO", the carrier frequency signal f is set to 15
kHz is set (step S23). The carrier frequency signal fc set in this manner is transmitted to the communication I / F 4
7 is serially transmitted to the first control circuit 21a.

The power consumption of the water supply pump 2, which is a variable speed pump, is substantially proportional to the square of the speed signal f. Inverter 21 when carrier frequency signal = 15 kHz
Is about 5% of that of the feedwater pump 2, and the loss of the inverter 21 when the carrier frequency signal is 1 kHz is about 3% of that of the feedwater pump 2.

Therefore, when the carrier frequency signal fc is switched according to the speed signal f as shown in the flowchart of FIG. 2, the relationship between the speed signal f and the loss of the inverter 21 is as shown in FIG. As shown.

That is, since the loss of the inverter 21 is almost proportional to the square of the speed signal f, it becomes a quadratic curve as shown in FIG. Here, in the case of the same speed signal f,
The loss of the carrier frequency signal fc of 15 kHz is larger than that of the carrier frequency signal fc of 1 kHz.

When the speed signal f is 75% or less, the carrier frequency signal fc is set to 15 kHz. Therefore, the loss of the inverter 21 is proportional to the square of the speed signal f as shown by a. To increase.

On the other hand, when the speed signal f is larger than 75%, the carrier frequency signal fc is set to 1 kHz, so that the loss of the inverter 21 is proportional to the square of the speed signal f as shown by b. To increase.

Therefore, when the speed signal f becomes larger than 75%, the carrier frequency signal fc is switched to 1 kHz. If the frequency signal f is not switched, the loss of the inverter 21 increases as shown by the broken line a1. Can be held down as small as possible.

For example, the relationship between the speed signal f and the noise level when a squirrel-cage induction motor is used as the motor 1 in FIG. 1 is as shown in FIG. In FIG. 6, when the speed signal f is larger than 75%, the carrier frequency fc is set to 1 kHz. Thus, the carrier frequency fc
Is 1 kHz, the electromagnetic sound is within the audible range, and even if the speed signal f decreases, the electromagnetic sound does not decrease so much. The total noise level of the sum of the noise and the mechanical noise does not decrease so much.

On the other hand, when the speed signal f is 75% or less, the carrier frequency fc is set to 15 kHz. As described above, when the carrier frequency fc is at 15 kHz, the electromagnetic noise is outside the audible range, so that the overall noise level decreases as the speed signal f decreases.

In this way, as shown in the flowchart of FIG. 2, when the carrier frequency fc is switched when the speed signal f reaches 75%, the overall frequency is changed as shown by the solid line in FIG. The noise level is reduced.

In particular, when controlling the number of the water supply pumps 2 as a plurality of variable speed pumps in accordance with the amount of water used, 1
Only the stage is operated at variable speed, and the other pumps operate at speed signal f = 10
It runs at 0% and often runs in parallel.

In this case, the noise level of the pump operating at the speed signal f = 100% is as shown in FIG. 6 when the carrier frequency fc = 1 kHz and when the carrier frequency fc = 1.
There is not much difference between the case of 5 kHz.

Therefore, as shown in the flowchart of FIG. 2, by switching the carrier frequency signal fc in accordance with the speed signal fc as in this embodiment, the operation at the speed signal f = 100% is performed. Without compromising the noise level
As shown in FIG. 5, the loss can be reduced.

When a DC brushless motor is used as the motor 1 in FIG. 1, the relationship between the speed signal f and the noise value of the motor 1 is as shown in FIG. As shown in FIG. 7, when the speed signal f is 75% or more, the carrier frequency signal fc is set to 15 kHz, and the speed signal f is set to 75%.
If it is less than 1, the carrier frequency signal fc is set to 1 kHz.

When the speed signal f is smaller than 75%,
The carrier frequency signal fc is set to 1 kHz. However, when the speed signal f is small, noise increases. Therefore, while the speed signal f is small, the noise level is reduced as indicated by a broken line by operating the carrier frequency fc at 15 kHz.

As described above, by changing the carrier frequency fc according to the speed signal f, both prevention of heat generation and prevention of noise can be achieved. Next, a second embodiment of the present invention will be described with reference to the flowchart of FIG. In the first embodiment described above,
Although the carrier frequency fc is switched in accordance with the magnitude of the speed signal f, in the second embodiment, a temperature sensor 61 is provided as temperature detecting means for detecting the ambient temperature の of the inverter 21. The ambient temperature Θ is compared with the predetermined temperature Θo (step S31).

Here, the temperature sensor 61 is connected to the inverter 21.
Is installed in the vicinity of the inverter 21 so as to detect the ambient temperature of the CPU 4 and the CPU 4 through an A / D converter (not shown).
2

When the ambient temperature detected by the temperature sensor 61 is equal to or higher than a predetermined temperature, control is performed with the carrier frequency fc = 1 kHz (step S3).
2) If the ambient temperature is lower than the predetermined value, the operation is performed at the carrier frequency fc = 15 kHz (step S33).

Generally, cooling is performed so that the temperature inside the control panel of inverter 21 is about 50 ° C. or less. However, the ambient temperature of the inverter 21 fluctuates by about 40 ° C. due to the season and the difference between day and night. In the second embodiment, when the temperature can be easily reduced to 50 ° C. or less during winter or night without taking much heat measures, the operation is performed at the carrier frequency fc = 15 kHz. Priority is given to reduction.

The first embodiment and the second embodiment
In the embodiment, the carrier frequency fc is switched in two stages in accordance with the speed signal f or the ambient temperature の of the inverter 21. However, the switching of the carrier frequency fc is not limited to two stages but may be performed in three or more stages. Switching may be performed.

Further, in the above embodiment,
Although the carrier frequency fc is switched according to the speed signal f or the ambient temperature の of the inverter 21, the parameter to be switched is not limited to the carrier frequency fc, and another parameter may be switched.

Further, in the above embodiment,
The start-up signal S, the speed signal f, and the carrier frequency fc as parameters of the inverter 21 are transmitted to the communication I / Fs 47, 51
, But the communication I / F 47,
It does not have to be performed via 51.

[0053]

According to the first aspect of the present invention, the carrier frequency, which is a parameter of the inverter, is switched according to the operating frequency of the pump, so that both noise generated by the pump and reduction of heat generation can be achieved. be able to.

According to the second aspect of the present invention, since the carrier frequency, which is a parameter of the inverter, is switched according to the ambient temperature of the inverter, it is possible to achieve both the noise generated by the pump and the reduction of heat generation. it can.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a variable speed pump device according to a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining carrier frequency switching control according to the embodiment;

FIG. 3 is a flowchart for explaining on / off control of automatic operation according to the embodiment.

FIG. 4 is a flowchart for explaining automatic start / stop control according to the embodiment;

FIG. 5 is a diagram showing a relationship between a speed signal f and a loss of an inverter according to the embodiment.

FIG. 6 is a diagram showing a relationship between the speed signal f and the noise level of the variable speed pump device according to the embodiment.

FIG. 7 is a diagram showing a relationship between the speed signal f and the noise level of the variable speed pump device according to the embodiment.

FIG. 8 is an output power waveform diagram of the inverter according to the embodiment.

FIG. 9 is a flowchart illustrating carrier switching control according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Motor, 2 ... Water supply pump, 21 ... Inverter, 21a ... 1st control circuit, 21b ... Main circuit, 21c ... 2nd control circuit 22, 42 ... CPU.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihisa Shimada 1-Gorita, Hashime-cho, Okazaki-shi, Aichi F-term in Okazaki Plant of Kawamoto Manufacturing Co., Ltd. 3H045 AA09 AA23 BA03 BA07 BA38 BA43 CA04 CA06 CA24 DA07 EA13 EA14 EA16 EA26 EA36 EA41 5H576 AA05 BB04 EE18 EE30 FF01 FF05 GG02 HA02 HB01 JJ17 KK06 LL43 LL48 LL49

Claims (2)

[Claims] An inverter control means for controlling an operation frequency of an electric motor for driving a variable speed pump; an operation frequency of the pump calculated according to an operation state of the pump, and output to the inverter control means;
Automatic start / stop control means for automatically starting and stopping the variable speed pump; and carrier frequency control means for increasing / decreasing a carrier frequency output to the inverter control means in accordance with the operation frequency of the pump. A variable speed pump device characterized by the following. 2. An inverter control means for controlling an operation frequency of an electric motor for driving a variable speed pump, an operation frequency of the pump is calculated in accordance with an operation state of the pump, and the calculated operation frequency is outputted to the inverter control means.
Automatic start / stop control means for automatically starting and stopping the variable speed pump; and carrier frequency control means for increasing / decreasing a carrier frequency output to the inverter control means according to an ambient temperature of the inverter control means. A variable speed pump device characterized by the above-mentioned.