JP3288625B2 - Inverter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter provided for a motor and controlling each motor, and more particularly to an inverter used in a water supply device for supplying water with a plurality of electric pumps provided in parallel. The present invention relates to an inverter suitable for controlling an electric pump under its control in cooperation with each other.

[0002]

2. Description of the Related Art In a conventional water supply system using a variable speed pump, a control circuit having a microcomputer for instructing the operation of the inverter is separately provided. By issuing the command, the operating speed of the electric motor that drives the pump is changed, and the water supply is continued while maintaining the pressure on the discharge side of the pump in a fixed relationship (for example, constant discharge pressure or constant end pressure). Related devices of this type include, for example, Japanese Patent Publication No. 6-52079 and Japanese Patent Publication No. 6-5
No. 2080.

In addition, various protection circuits are incorporated in an inverter device combined with this type of water supply device in order to protect the inverter device itself. Related to the protection method of this type of inverter device, for example,
JP-A-57-6576, JP-A-58-224575
No., JP-A-59-185170, JP-A-60-849
No. 72, JP-A-61-224876 and the like.

[0004] In a water supply device incorporating such an inverter device, various protection circuits are incorporated in the inverter device in order to protect the inverter device itself.
The inverter device is stopped due to various factors (instantaneous power failure, overload, temperature rise, mixing of noise, etc.). If the inverter device stops and the pump cannot be driven and water is cut off, the problem becomes even greater. Therefore, usually, the motor for driving the pump is switched from the variable speed operation by the inverter to the operation by the commercial power supply (ie,
It becomes a constant speed operation. ), To avoid water interruption.

[0005]

In the conventional water supply device,
If the inverter device with a built-in microcomputer breaks down, the pump is operated at a constant speed with commercial power to avoid water interruption. There is also a problem that the discharge pressure fluctuates greatly. Further, in the constant-speed operation of the pump using a commercial power supply, there is also a problem that the operating power cost increases because the pump operates at the full speed even under a light load.

For this reason, it is desired that each of the plurality of pumps be controlled by an inverter so that even if one inverter fails, the pump can be operated at a variable speed by another inverter. In this case, if multiple inverters control the inverters independently, it becomes impossible to continue smooth water supply when one inverter fails, thus solving the problem of how to coordinate control between inverters in the event of a failure. There is a need to.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inverter suitable for use in a water supply device which is used in a water supply device or the like in which a plurality of inverters each control a pump and can smoothly continue water supply even when one of the inverters fails. Is to provide.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inverter for controlling the operation of a motor to be controlled, which incorporates a microcomputer for controlling the operation of the motor and inputs / outputs an operation state with another inverter. This is achieved by providing means for performing

[0009]

[Function] The other party is monitored through a signal path connecting the microcomputers controlling the respective inverters. If the other party is determined to be abnormal, a re-run command is output to the other party, or the self-start / stop operation is performed. When the other party breaks down, if the other party is a temporary failure, the other party can be started immediately, and if the other party breaks down, the self can be started immediately, so that the smooth operation of the motor can be continued. it can.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, a control device 1 is configured by inverter devices 20 and 21 and leakage leakage breakers 40 and 41 each having a built-in control means, and controls the water supply unit 2. The water supply unit 2 includes pumps 105 and 10 with electric motors.
6, pressure sensors 102 and 112, and flow switch 1
07, 117, the inflow side merging pipe 104, the discharging side merging pipe 110, the pressure tank 111, and the pressure gauges 114, 115.
And various valves 100, 101, 103, 108, 10
9 to increase the water pressure of the water main 116 and supply water to the water distribution pipe 118.

The main circuit power supply 10 supplies three-phase AC power to the control device 1. The inverter devices 20 and 21 have terminals R and
Receiving power from S and T and outputting variable frequency AC power to terminals U, V and W according to a pre-programmed operation bill;
The variable speed operation control of the pumps 105 and 106 with a motor is performed.

The pump with electric motor 105 and the pump with electric motor 106 perform an automatic alternate operation. For this reason, the control means of the inverter device 20 and the control means of the inverter device 21 mutually monitor each other by the interlock signals 61 and 62 to control their own start / stop.

In FIG. 2, a noise filter 60 and a zero-phase reactor 50 attenuate electrical noise superimposed on the main circuit power supply 10 to protect the inverter devices 20 and 21 and generate the inverter devices 20 and 21. This prevents electrical noise associated with the higher harmonic current from returning to the main circuit power supply 10. The zero-phase reactors 51 and 5
2 is a pump 1 with an electric motor,
By suppressing the transient current applied to the pumps 05 and 106, noise generated when the pumps 105 and 106 with electric motors are driven is reduced.

The earth leakage breakers 40 and 41 perform earth leakage detection for preventing electric shock,
It is used as a power switch at the time of maintenance work of the inverter 106 and the inverter devices 20 and 21.

The digital operators 30 and 31 are accessories of the inverter devices 20 and 21, and operate the push buttons on the lower part of the front to operate the inverter devices 20 and 21.
Initial setting and test operation can be performed, and the operating status can be monitored by displaying the output frequency, load current, failure information, and the like of the inverter devices 20 and 21 on the numeric display at the top of the front.

In FIG. 3, inverter devices 20, 21
The input / output signal terminals provided in the above will be described below. The interlock signals 61 and 62 include an output signal terminal DO2 for notifying another inverter device that the inverter device has stopped (self tripped) due to the function of its own protection means,
Restart command signal from another inverter (alternate command E
NQ) input terminal DI1 and another inverter stop due to the action of its own protection means (counterpart trip)
Input terminal DI2 for inputting a notification that the operation has been performed, and a restart command signal (alternate command ACK) for another inverter device.
From the output signal terminal DO1.

The sensor input terminals AI1 and AI2 are analog input terminals for receiving signals from the pressure sensors 102 and 112. Also, the signal FS of the flow switch 107
Is taken in as a bit signal from the FW terminal. Signals from the digital operators 30 and 31 are connected by serial communication ports SD and RD. In this embodiment, the bit output terminals DO3 to DO5 for notifying the abnormality detected by the inverter devices 20 and 21 to the outside are also provided.

FIG. 4 is a block diagram of the software of the microcomputer constituting the control means built in the inverter devices 20 and 21. In the figure, in a normal process 401, in accordance with a stored pump operation bill,
Based on the data from the interlock signal and the pressure sensor signal, an output frequency of the inverter and an operation / stop command are calculated, and the command is sent to the LAD process 402. LAD processing 402
Then, based on the given output frequency, operation / stop command and the characteristics of the inverter itself, a detailed output frequency and output voltage command is generated and commanded to the PWM process 403. P
The WM process 403 converts a PWM signal (pulse width control signal) for driving a switching element in the inverter main circuit 407 such that the inverter outputs variable frequency power according to the given output frequency and output voltage command. Output to

When an overcurrent reference value which is a detection level of an overcurrent of the load current of the inverter is output from the normal process 401 to the trip process 404, the trip process 404 stores the overcurrent reference value. The trip process 404 constantly monitors the overcurrent reference value and the load current of the inverter, and when the overload current is detected, generates trip information and notifies the command process 405. In addition, the PN of the inverter main circuit
The intermediate voltage (the voltage between the positive electrode and the negative electrode of the intermediate DC voltage) is input to the normal processing 401, where overvoltage and undervoltage are detected, and this detection signal is output to the trip processing 404.

The command processing 405 is a processing for abnormalities (overcurrent, overvoltage,
Communication processing based on key information of the digital operators 30, 31;
LED display signal output to the nonvolatile memory (EEPR)
OM) 408 executes exception processing such as data reading / writing. The EEPROM input / output processing 406 directly accesses the non-volatile raw memory 408 in response to an EPROM writing command or a call request command from the command processing 405, and needs to store basic parameters and failure history data required for an operation bill even after a power failure. The transfer of certain data is executed between command processing 405 and the command processing 405.

FIG. 5 is a flowchart showing an example of the normal processing 401. When the power is turned on to the inverter devices 20 and 21, the normal process 401 starts with an initial setting process 501.
And the discharge target pressure HO, the minimum operation speed NS, and the maximum operation speed N, which are parameters necessary for the operation control of the pump.
f, speed change width ΔN, re-operation judgment time T, number of re-operations m
Is read from the nonvolatile memory 408 and set in a register for calculating the output frequency of the inverter.

In the next process 502, the pressure sensor 102,
The signal from the switch 112 and the signal from the flow switches 107 and 117 are taken in from the input terminals AI1, AI2 and FW, respectively. In the next process 503, the interlock signal 6
The operation state of another inverter device (hereinafter, referred to as a partner inverter device) in the control device 1 is input via the control units 1 and 62, and the own operation state is output to the partner inverter device.

In the next process 504, the operation state of the partner inverter device is examined. If it is normal, the process proceeds to the next pump control process 505, and if abnormal, the process 510 is executed to restart the partner inverter device. After execution, the process 505
Proceed to.

In the process 505, the current feed water pressure H is compared with the target pressure HO. If H> HO, the process proceeds to the processes 508 and 509 to perform the deceleration process, and then returns to the process 502, where HO> H If it is, the process proceeds to Steps 506 and 507 to perform the speed increasing process and returns to Step 502. When H = HO, the process returns to the process 502 without executing the speed change process.

By repeating the above process, in the normal process 401 of FIG. 4, the status monitoring of the partner inverter, the restart process in the event of an abnormality, and the shift operation process of the feedwater pump are executed in parallel.

In the above description of the embodiment, an example in which two inverters are used has been described. However, even when three or more inverters are used, an interlock signal can be exchanged between the respective inverters. The same can be done.

[0027]

According to the present invention, it is possible to constantly monitor the other party and immediately take action if there is an abnormality. Therefore, even if a failure occurs in the inverter, the motor can be smoothly continued by another inverter. Becomes

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a water supply device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a control device portion of the water supply device shown in FIG.

FIG. 3 is a detailed explanatory diagram of terminals of the inverter device.

FIG. 4 is a block diagram illustrating a software operation of the inverter device.

FIG. 5 is a flowchart showing a basic processing procedure of the software shown in FIG. 4;

[Explanation of symbols]

10: main circuit power supply, 20, 21: inverter device, 3
0, 31 ... digital operator, 40, 41 ... earth leakage breaker, 50, 51, 52 ... zero-phase reactor, 61, 62 ...
Interlock signal, 100: double check valve, 101: check valve, 102, 112: pressure sensor, 103, 108, 1
09 ... gate valve, 104 ... inlet side merging pipe, 105, 106
... Pumps with electric motors, 107, 117 ... Flow switches, 110 ... Merging pipes on the discharge side, 114, 115 ... Pressure gauges
116: Main water pipe, 117: Water distribution pipe.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H02P 7/74 H02P 7/74 G (72) Inventor Koji Ohno 7-1-1 Higashi Narashino, Narashino-shi, Chiba Hitachi, Ltd. JP-A-2-286888 (JP, A) JP-A-5-231332 (JP, A) JP-A-5-231331 (JP, A) JP-A-2-86974 (JP, A A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F04D 15/00-15/02 F04B 49/00-49/10 H02P 7/63 H02P 7/74

Claims (2)

(57) [Claims] An electric port of a liquid supply device directly connected to a water main.
In the inverter that controls the operation of the pump,
Signal of pressure detecting means for detecting water pressure on the side and pump
Takes the detection signal of pressure detection means that detects the water pressure on the discharge side.
From the pressure signal input terminal
Control the operation of the electric pump according to the detected pressure
A microcomputer performed by software processing;
Microcomputer is running between other inverters
Operation status input / output terminal for inputting / outputting status and abnormality detected
When an error notification output terminal outputs the error occurrence to the outside,
The abnormality notification output terminal is provided with a “flow”
Incoming pressure drop, discharge pressure drop, pump failure
An inverter , comprising: a plurality of terminal groups that output signals to a plurality of terminals . 2. A water supply device for a water supply directly connected to a water main.
In an inverter that controls the operation of an electric pump, the pump
A detection signal of pressure detection means for detecting the water pressure on the inflow side of
Detection signal of pressure detection means for detecting water pressure on pump discharge side
Pressure signal input terminal that captures
Operation control of the electric pump according to the detected pressure
A microcomputer that performs control by software processing
And the microcomputer communicates with another inverter.
Input / output alternate operation command and / or trip status
Operation status input / output terminal and the occurrence of an error when an error is detected
And an abnormality notification output terminal for outputting the abnormality to the outside.
The notification output terminal is "lower inflow pressure" of the water supply system,
Multiple outputs that output "Discharge pressure drop" and "Pump failure" respectively.
An inverter comprising a number of terminal groups .