JP5286238B2 - Water supply device and control method of water supply device - Google Patents

Description

The present invention relates to a plurality of inverters for driving a plurality of turbomachines and their application devices.

In a turbo machine such as a turbo pump and a turbo blower, the amount of water supplied and the amount of air are proportional to the operating speed, the water supply pressure and the wind pressure are proportional to the square of the operating speed, and their outputs are proportional to the cube of the operating speed. This indicates that the operation speed can be lowered as the load amount is reduced, and there is an advantage that energy can be saved.

  Conventionally, a plurality of inverters are used to control the speed so as to maintain the discharge side pressures of the plurality of turbomachines in a certain relationship, and the operation order and the number of units of the plurality of inverters and turbomachines are controlled.

  Therefore, when the plurality of turbo machines are driven by a plurality of inverters, and the speed control and the number of operating units are controlled, the water supply amount, the air amount, the water supply pressure, and the wind pressure can be controlled efficiently according to the load fluctuation. For this reason, it is considered that speed control using inverters will become increasingly popular in the future.

  Among these, the example which used the inverter for the water supply apparatus is demonstrated with reference to FIGS. FIG. 1 is a configuration diagram of a water supply device, where 1 is a water distribution pipe, 2-1, 2-2 are distribution pipe branches, 3-1, 3-2, 3-3, 3-4 are gate valves, -1, 4-2 are pumps, 5-1 and 5-2 are electric motors, 6-1 and 6-2 are check valves, 7 is a water supply pipe, 8 is a pressure tank having an air reservoir inside, and 9 and 10 Are pressure sensors that detect the pressure on the pump suction side and the pump discharge side, respectively, and generate an electrical signal corresponding to the pressure of the detection unit. FS1 and FS2 are flow switches, which are turned on when the amount of water is less than QS shown in FIGS. 2 and 3 described later. The CNU is a control device, and is composed of a power circuit unit, a relay circuit unit R, and a controller CU including inverters INV1 and INV2 that drive the motors 5-1 and 5-2 at a variable speed, a leakage breaker ELB1 and ELB2 that protects against leakage. ing. The relay circuit R includes a transformer TR, a stabilized power supply Z, relays 52X1 and 52X2, and an interface I / O between the relay circuit R and the controller CU.

  The controller CU is an arithmetic processing unit CPU (hereinafter abbreviated as CPU), an A / D converter for converting signals (analog quantities) from the pressure sensors 9 and 10 into digital signals, and a water supply system for the inverters INV1 and INV2. A signal S4 is transmitted to the D / A converter that commands the desired speed command signals N1 and N2, the power supply terminal E for supplying power to the controller CU, and the interface I / O for driving the relays 52X1 and 52X2 described above. Therefore, an output port PIO-1 is provided. Similarly, each of the input port PIO-2 for reading the set value set by the setting means C so as to operate according to the operation characteristics of the pump shown in FIGS. 2 and 3 and the leakage breakers ELB1 and ELB2 are leaked. Are provided with input ports PIO-3 for reading the states of the contacts ELBAL1 and ELBAL2 which are operated when tripped by the above and the contacts INVAL1 and INVAL2 which are operated when the inverters INV1 and INV2 are tripped due to overload or the like. That is, the CPU executes a command and control to stop the pump and switch to the other pump that is at rest in accordance with these fault conditions.

  FIG. 2 is an operation characteristic diagram when one pump is operated alone or two pumps are alternately operated by the water supply device described above, and the vertical axis indicates pressure H and the horizontal axis indicates water quantity Q. A curve A is a QH performance curve when the pump is driven at an operation speed N3, that is, a 100% operation speed by an inverter. Similarly, curves B, C, and D are QH performance curves when the pump is driven at the operation speeds of N2, N1, and N0, respectively. Curve F is a pipe resistance curve. For example, when the amount of water used changes from the amount of water Q1 to the amount of water Q0, if water is supplied at a pressure along the curve F on the discharge side of the pump, the water supply system at the terminal faucet Indicates that the desired pressure is obtained. The inverters INV1 and INV2 are externally set by the consoles CONS1 and CONS2 under what conditions, for example, acceleration / deceleration time and V / F (output voltage and output frequency characteristics, etc.). That is, the water supply device operates the pump along the curve F along O3-> O2-> O1-> O0.

  In FIG. 1, when the earth leakage circuit breakers ELB1 and ELB2 are turned on and the control power supply circuit breaker CB is turned on, the power supply of the control unit CU is established, and the CPU is initialized based on the program stored in the memory M in advance. Setting is performed, setting information is read from the setting means C, the state of the inverter and the earth leakage breaker (not faulty) is read from the input port PIO-3, and the signals of the pressure sensors 9, 10 are further converted into an A / D converter. Read through. In addition, a pipe resistance curve F is stored in advance, and the supply water pressure is changed along the resistance curve F corresponding to the change in the operation speed when the load state changes. Thus, preparation for operation is completed. When water is used in this state, the water supply pressure decreases. When the starting pressure HON shown in FIG. 2 is lowered, the CPU outputs a signal for energizing the relay 52X1 to the interface I / O via the output port PIO-1. At the same time, a signal of the operation speed N1 is output to the inverter INV1 via the D / A converter. As a result, the inverter INV1 is started and the electric motor 5-1 is driven. After operation, the feed water pressure is controlled based on the signal from the pressure sensor 10 so as to be on the curve F. When the amount of water used decreases and the pump stop condition is established, the CPU releases the energizing signal of the relay 52X1 and the speed command signal N1 to the inverter INV1 that are currently output. As a result, the pump 4-1 stops. When water is used again and the start-up condition is established because the water supply pressure is HON or less, the relay 52X2 and the operation speed N2 signals are issued, and the other inverter INV2 and the motor 5-2 are now driven to drive the pump 4-2. To drive. Thereafter, similarly, switching control is performed and alternate operation is performed.

  FIG. 3 is a characteristic diagram when two pumps are operated in parallel, and the same reference numerals as those in FIG. 2 have the same meaning. That is, as shown in FIG. 2, when two pumps are operated alternately and the amount of water used is further increased, the pumps 4-1 and 4-2 are simultaneously operated. When the amount of water used is Q3 or more, the operation speed N3 is the maximum speed, so that the water supply capacity is insufficient and the water supply pressure decreases to HL. As a result, the CPU issues signals of relays 52X1, 52X2, and speeds N1, N2. In this way, the inverters INV1, INV2 and the motors 5-1, 5-2 are operated simultaneously, and the pumps 4-1, 4-2 are operated in parallel. After the operation, control based on the signal of the pressure sensor 10 is performed so that the feed water pressure is on the curve F.

  In FIG. 3, when the amount of water used decreases, the operation speed becomes N4 + N3, and when the feed water pressure becomes HH, one of the two stops and becomes an independent operation.

For these, Japanese Patent Publication No. 5-231332 is referred to as Patent Document 1.
Thus, conventionally, in order to drive two inverters, a main control device for controlling the inverters is required at the upper level.

The above prior art has the following problems. That is,
(1) In the conventional system, even if the two inverters are normal, there is a problem that if the main controller stops operating due to an abnormality, the system goes down and water is shut down.
(2) When the system is configured with a dual inverter, since it has individual control functions, even if one unit goes down due to a failure, the other unit can perform backup operation. However, it is difficult to convey the control status of each other because of the individual control functions. In order to operate the inverters alternately and in parallel, interlock each other outside the inverter, detect these states, and issue an operation command. There is a need. In addition, there are many interlock signals and the control logic is complicated.

Japanese Patent Publication No. 5-231332

  The present invention has been made in view of the above points, and an object of the present invention is to provide a dual inverter that does not require an external peripheral device, can easily perform signal sharing, and can be reduced in size, weight, and cost. And to obtain the application device.

In order to achieve the above object, the present invention provides a water supply device that supplies water with at least two or more pumps each controlled by an inverter. A first setting switching means for switching the setting as a subsequent machine that is started later and performs pump control after the starting machine is stopped, and the inverter set as the subsequent machine is provided after the starting machine is started. When the starting machine stops, the second setting switching means for switching the setting as the starting machine and when the starting machine operates together with the succeeding machine, the succeeding machine requests the starting machine. The starting machine performs constant discharge pressure control while accelerating until reaching a set speed after the start of operation by the following, after which the succeeding machine operates at a constant speed, and the starting machine Is characterized in that and a parallel operation means for estimating constant end pressure control as common pressure becomes a predetermined target pressure on the pump discharge side without the constant speed.

In order to achieve the above object, a preferred embodiment of the present invention is set as a starting machine that starts up first and performs pump control in a water supply apparatus that supplies water with at least two pumps each controlled by an inverter. In addition, after the starter starts, the first setting switching means for switching the setting as a starter which starts the inverter later and performs pump control after the starter stops operation, and the inverter set as the starter When the starting machine stops, the second setting switching means for switching the setting as the starting machine and the succeeding machine are operated at a constant speed, and the pressure common to the pump discharge side becomes the predetermined target pressure. Parallel operation means for performing constant control of the estimated terminal pressure as described above.
Moreover, in the said aspect, it is desirable to have the following aspects.
(1) When the parallel operation is performed by the parallel operation means and the starter machine stops, the estimated terminal pressure constant control is performed by the subsequent engine.
(2) Provide with a failure detection means for detecting the failure of the starter machine, and when the failure detection means detects a failure of the starter machine, operate with the latter machine
(3) The parallel operation means operates the starting machine so that the pressure common to the pump discharge side becomes a constant value until the succeeding machine accelerates to the constant speed.
(4) When the parallel operation is performed by the parallel operation means, the starter is at a predetermined speed or lower, and the common pressure on the pump discharge side is higher than the predetermined pressure, the starter is stopped.

FIG. 1 is a block diagram of a conventional turbomachine drive device. FIG. 2 is an operation characteristic diagram when the pump is operated alone or alternately. FIG. 3 is an operation characteristic diagram when two pumps are operated in parallel. FIG. 4 is an overall configuration diagram of a system illustrating a water supply device as a turbo machine according to the present invention. FIG. 5 shows the terminal details of the dual inverter according to the present invention and the description of the connection signal. FIG. 6 is a time chart showing the procedure of power-on processing of the apparatus shown in FIG. 4 according to the present invention. FIG. 7 is a time chart showing a control method of parallel operation of the apparatus shown in FIG. 4 according to the present invention. FIG. 8 is a flowchart for realizing the processing of FIGS. 6 and 7 according to the present invention.

The outline of the embodiment of the present invention will be described as follows.
The signal content necessary for signal exchange of the dedicated inverter is minimized as much as possible. The conventional I / O port of a general-purpose inverter is used as it is. By detecting the pump operation, stop, parallel operation start detection, and release detection only with the preceding inverter, the complicated signal between the mutual inverters is simplified, and the mutual interlock signal is minimized, preferably 2 It is connected with two outputs and two input signals, and exchanges signals with each other. Further, these inverters are set in advance by a setting unit to set how to operate the inverter, or set an operation pattern of a load, and set which one is to be operated first. In this way, alternate and parallel operation, retry at the time of abnormality, and backup operation are performed. The earth leakage breaker provides short circuit protection for the main circuit and earth leakage protection on the secondary side, and cuts off the main circuit. The inverter drives the turbomachine and is composed of a double system. The signals of the pressure sensor for detecting the load state, the underload state detecting means, and the suction side pressure sensor are directly taken in parallel at the same level. Each inverter is preinstalled with a software program for operating a microcomputer in which a control method and a procedure are described, and operates according to an input signal from a sensor or the like. In the initial stage of use, when the earth leakage breaker is turned on, the power sources of both inverters are established, and the one set in advance as a priority machine waits for operation. When the pressure sensor that detects the load state detects a preset start pressure, the standby inverter starts. A sensor that detects an underload condition detects this, and when a preset stop condition is established, the inverter stops, and the inactive inverter is made ready for operation by a stop signal from the preceding machine and started as described above. , Stop. Furthermore, when the pressure sensor that detects the load state detects a preset parallel operation pressure state, the operating inverter outputs a parallel operation request signal to the inactive inverter, and the inactive inverter Operate in parallel from the ready state. In addition, when an earth leakage breaker trip or inverter trip occurs, this state is transmitted to each other by a signal line connecting the two inverters, switching from the stop on the abnormal side to the normal operation, and the internal side generates an internal signal. And retry. Further, this state is displayed by an error code on the panel display of the inverter, and a signal is transmitted to the outside. In addition, the pressure, current, voltage, and frequency values are displayed using this display unit.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings.
FIG. 4 is an overall configuration diagram showing an embodiment in which the present invention is applied to a water supply apparatus, and what is denoted by the same reference numerals as those in FIG.

  In the figure, the control device CNU includes leakage breakers ELB1, ELB2, inverters INV1, INV2, and noise filters ZCL0, ZCL1, ZCL2. This is because the relay circuit R and the control unit (both hardware and software) CU shown in FIG. 1 are incorporated in the inverters INV1 and INV2.

  That is, the inverters INV1 and INV2 output the trip signal AL of the leakage breakers ELB1 and ELB2 as ELB trip signals to the control panel external terminals via the signal lines S1 and S2.

  The signal FS1b or FS2b of the flow switch FS1 or FS2 is input to the terminal DI4-COM via the signal line S4 or S5, and the signal of the pressure sensor 9, 10 is input to the terminals AN0 and AN1 via the signal lines S6 and S7, respectively. , L. Since the pressure sensors 9 and 10 are commonly used for the inverters INV1 and INV2, they are connected by a signal line S8.

  The terminals DI1, DI2, DO1, and DO2 of the inverters INV1 and INV2 are connected by a signal line S3, and signals such as an operation state, a failure state, and an operation request are exchanged. The DI3 terminal is a selection signal for the priority machine, and the inverter INV1 is short-circuited with COM.

  Further, signal lines S9 and S10 are signals for outputting a failure of the inverters INV1 and INV2 to a central monitoring panel or the like.

  FIG. 5 and Table 1 show details of the contact signal S3 of the inverters INV1 and INV2. Table 1 is a symbol table showing the output state and control state of the contact signal of the dual inverter according to the present invention.

  The interlock signals of the inverter 1 and the inverter 2 have two outputs and two inputs, respectively. By turning on and off the 2-bit signal, four types of states can be notified to the other party.

  In FIG. 5, if the states of the outputs DO1 and DO2 are shown in the states A to D shown in Table 1, the state A is a pump that is operating in advance with both DO1 and DO2 ON. Indicates a “parallel activation request” signal.

  If it is the next pump, it indicates a “parallel constant speed state” signal that is output when a preset maximum speed constant state is reached. This occurs when both are in automatic mode and set to run in parallel. State B shows a state of “automatic alternate (parallel) operation” in which DO1 is ON and DO2 is OFF. State C shows a state of “automatic alternate (parallel) standby” with DO1 OFF and DO2 ON. State D indicates the state of “moving alone operation mode”, “manual mode”, “failure stop”, or “power-off” when both DO1 and DO2 are OFF. Indicates a state that cannot be operated alternately or in parallel. With the above signals, it is possible to realize an interaction such as backup operation at the time of alternating, parallel, and failure.

  The details of the signal connection will be described with reference to the time charts of FIGS. First, using the time chart of FIG. 6, the alternate operation after power-on and the operation at the time of abnormality will be described. At time 1 in the figure, the power source of the inverter 1 rises and the state changes from D to C. At this time, the power source of the counterpart inverter 2 has not yet started up, so it remains in the D state. Since only the inverter 1 can be pumped, the inverter 1 automatically operates in a single operation. At time 2, the inverter 1 detects the pump start condition, and the inverter 1 operates. At this time, the inverter 1 outputs the B state from the C state to indicate that it is in operation. At time 3, the pump stop condition is detected, and the inverter 1 stops and outputs the C state from the B state.

  Next, since the power source of the inverter 2 has risen at time 4, the inverter 2 outputs the C state from the D state. Since the inverter 2 is in the C state and can be operated alternately or in parallel, the inverter 1 shifts from the single operation to the alternating or parallel operation state. At time 5, the pump start condition is detected. At this time, both the inverter 1 and the inverter 2 capture the same sensor signal, so the start condition is satisfied at the same time. However, since the inverter 1 is set as the priority machine, the inverter 1 starts first and outputs B from the state C. To do. The inverter 2 is already in the alternating mode because the inverter 1 is in the C state when the power is turned on, but the non-priority machine has a start-up condition by delaying operation even if the start-up condition is detected. Even if it is established at the same time, the inverter 1, which is a priority machine, operates first and outputs the B state, so the inverter 2 stops operating. In this way, simultaneous activation is prevented by setting the timing. After time 5, since the preceding machine and the next engine are clear, the stop is performed at time 6, the start condition is established at time 7, and the inverter 2 is operated. Thereafter, alternate operation is performed in the same manner. When a failure occurs in the inverter 1 at time 10, the state of the inverter 1 changes from B to D. At this time, the stopped inverter 2 determines that the inverter 1 is in failure because the state of the inverter 1 has changed from B to D, and starts operation because the activation condition is detected, and outputs the state from C to B. When the failure of the inverter 1 is recovered at the time 11 when the inverter 2 is in operation, the inverter 1 outputs the state from D to C, and the normal alternating operation mode becomes possible, so that the inverter 1 enters the standby state. At time 12, the inverter 2 is stopped and normal alternating operation is performed after time 13.

  Next, the parallel operation will be described using the time chart of FIG. At time 1 in FIG. 6, in the same state as time 4 in FIG. 6, when a start condition is detected at time 2 in FIG. 6, it is set as a priority machine in the same manner as time 5 in FIG. The started inverter 1 starts operation first. If the parallel start condition is satisfied at time 3, the inverter 1 outputs a “parallel start request” A to the inverter 2 if the inverter 2 is in the state C in which the automatic operation is possible. Inverter 2 confirms that inverter 1 has output state A and starts operation. At this time, the inverter 2 outputs B from the state C and gradually increases the speed to the set speed (preferably the MAX speed). From time 3 to time 4, the inverter 1 performs a shift operation so that the discharge pressure becomes constant with O3 (the point of the highest target pressure on the first discharge side) of the F curve in FIG. 3 as a target value. When the inverter 2 reaches the set speed at time 4, the state B is changed to A and the fact that the “parallel constant speed state” is obtained is output. When the inverter 1 confirms the state A of the inverter 2, the inverter 1 performs a shift operation based on the estimated terminal pressure constant control according to the change in the water amount with the target values on the O3 to O5 of the F curve in FIG. When the inverter 1 detects the parallel release condition at time 5, the pump 4-1 is stopped and the state is output from A to C. The inverter 2 confirms that the inverter 1 is in the C state, and shifts from the constant speed operation based on the estimated terminal pressure constant control according to the change in the water amount at the target value on O0 to O3 of the F curve in FIG. Do the driving. In this manner, the start, parallel introduction, parallel release, and stop conditions can be detected only by the preceding machine and the control can be unified by the above-described signal interaction. Moreover, this system can suppress the pressure fluctuation at the time of parallel activation to be small, and the operating units can be switched in parallel.

  Next, a flow for realizing control as in the time charts of FIGS. 6 and 7 will be described using the flowchart of FIG. In the figure, “◯” indicates a symbol that outputs its own state. “□” indicates the state of the opponent's state as a symbol. In 800, a priority machine is determined in advance by an external terminal of the inverter. When the power is turned on in 801, the priority machine is forcibly set as the preceding machine and the non-priority machine as the next engine in 802. In 803, a standby state is established until the start condition is satisfied, and when the start condition is satisfied, the process proceeds to 804, where the process is divided depending on whether the preceding machine or the next engine is set.

  In the case of the preceding aircraft, start is started in 805, and it is confirmed whether or not it is in failure in 806. If normal, in 807, the target value on O0 to O3 of the F curve in FIG. The terminal pressure constant control is performed, and the underwater condition is confirmed at 808 during that period. If the condition is satisfied, the stop process is started at 809. If stopped, the setting is switched from the preceding machine to the next engine at 822 to prepare for the alternate operation. If the underwater condition is not detected at 808 and the parallel condition is confirmed at 810, the partner state is confirmed at 811, and if “automatic standby”, “Parallel start request” is output to the partner at 812 and parallel start Let In step 814, the counterpart state is confirmed in 813, and in step 814 until the counterpart enters the “parallel constant speed state”, in FIG. 3, O3 (the point of the maximum target pressure on the first discharge side) of the F curve in FIG. The discharge pressure is controlled to be constant. When it is confirmed that the partner state is the “parallel constant speed state”, in 818, control is performed with the target pressure on O3 to O5 of the F curve in FIG. In 820, the parallel release condition is confirmed, and if the condition is satisfied, the preceding machine is stopped in 821. In the meantime, if the next engine breaks down at 817 to 820, the control returns to 807 and control is performed with only one terminal pressure constant. In 819, the failure state of the preceding machine (self) is confirmed. If the preceding machine stops due to a failure or parallel release, the setting is switched from the preceding machine to the next generator at 822 in preparation for the next alternate operation in the same manner as in the case of the detection of the excessive water amount detection. The above is the processing as the preceding machine for realizing the time charts of FIGS.

  Next, regarding the processing of the next engine, if it is set as the next engine in 804, it is confirmed in 823 whether the partner preceding machine has been operated or is operating. If it is in operation, it is checked in 824 whether there is a parallel request, and if there is a request, in 826, parallel activation is performed. When activated, the vehicle is operated at a constant speed in 829 until the preceding aircraft stops. When started, the vehicle accelerates. At 828, when the vehicle reaches a predetermined constant speed, the preceding machine is informed of the “parallel constant speed state”. When the preceding machine stops at 829, the setting of the next machine is switched to the preceding machine at 830, and thereafter, the process is shifted to 806 as the preceding machine to perform constant terminal pressure control. In 823 to 824, when the preceding machine stops in a parallel request waiting state (during automatic waiting), the setting is changed to the preceding machine in 825 to prepare for the next start. . The above is the process as the next engine for realizing the time charts of FIGS.

  According to the above embodiment, it is composed of two turbomachines and two inverters that drive the turbomachines one by one. These inverters are equipped with a microcomputer, and include a status display unit and a control constant setting unit. , A signal of a sensor group for detecting the load state of the turbo machine is set in advance so that the control constant setting unit is operated based on the load state, and the minimum signal indicating the operation state and the failure state with each other Connected by a wire and two inverters perform constant terminal pressure control while interlocking with each other. In the control at the time of parallel start, a "parallel start request" signal is provided in the connection signal, When the machine detects a parallel operation start condition, it outputs a parallel start request signal to the inactive inverter to start the inactive inverter. "When a signal is output and the speed is gradually increased at a preset acceleration to reach a predetermined constant speed (preferably the maximum speed), a" parallel constant speed state "signal is output to the preceding machine. Controls the shift operation so that the target pressure on the discharge side of the first unit is constant until the inverter that is started in parallel is in “automatic operation” to “parallel constant speed state”. When the engine is in “Parallel Constant Speed” operation, the speed change operation is performed so that the estimated terminal pressure becomes constant control along the target discharge pressure on the second discharge side. Since the next machine is operating at a constant speed, the preceding machine that is shifting at a constant estimated end pressure can detect the preset parallel release condition based on its own rotation speed and pressure on the load side, The parallel release condition is that when the preceding machine reaches the minimum speed, When the stop pressure is reached, the preceding machine is stopped, output to the next engine, and the next engine that is operating at constant speed is preset from constant speed operation when it receives the “automatic standby” signal. Since the shift operation is performed so that the estimated terminal pressure is constantly controlled along the target discharge side target pressure, even if it is a dual inverter, the start / stop condition of the parallel operation can be detected only by the preceding one inverter. Became possible.

  Also, in the control of the transient state at the time of parallel activation, when the preceding machine detects the parallel operation activation condition, it issues an activation request to the inactive inverter, activates the inactive inverter, and the preceding machine has the inverter activated in parallel, The speed change operation is performed so that the discharge pressure is constant at the maximum target pressure on the first discharge side until the parallel constant speed state is reached. When the next machine that is started in parallel enters the parallel constant speed state operation, 2 While changing the discharge target pressure according to the target discharge side target pressure, speed change operation is performed so that the estimated terminal pressure is constant, until the next engine becomes stable when the transient state is unstable during parallel startup By not updating the discharge target pressure of the preceding machine, there is an effect that stable control of pressure can be performed by suppressing the divergence of the control state.

In addition, the signal that connects two inverters includes those that are stopped due to a failure, and this signal is expressed in the same state as the state that is output when the inverter power is cut off. It is now possible to jump over faults without having to capture signals individually.
In addition, a mode switch is provided, and a manual-off-automatic signal is connected to the external input terminals of the two inverters. In FIG. 4, DI5 is turned on and DI6 is turned off to turn "automatic", DI5 turned off, It is possible to make the control state of the two inverters the same by meaning that “manual” is set by turning on DI6 and “off” is set by turning both DI5 and DI6 off or on. became.

  In addition, by making one external input terminal of either of the two inverters short-circuited, for example, to become a “priority machine”, it is possible to prevent malfunctions during simultaneous operation when power is turned on or when a power failure is restored, The priority machine can be easily set by using an external terminal.

  In addition, since a complete dual system is constituted by the first system and the second system and a failure backup is taken, the reliability can be further improved.

In addition, the inverter is preinstalled with a program to operate according to the load operation pattern, and based on this, the inverter is set by the setting unit to operate, and the load state detecting means detects the starting pressure. Sometimes the inverter set as the priority machine starts, and the underload detection means detects the underload condition and stops when the stop condition is established. In addition, since the alternate operation or the alternate / parallel operation can be performed without the need for complicated logic, the control device is simplified, small and light, and the cost can be reduced. Furthermore, since the number of parts is reduced, the reliability is improved. In addition, the short circuit and leakage of the main circuit are monitored by the earth leakage circuit breaker, and other fault conditions on the load side are monitored by the inverter itself due to changes in the internal state quantity of the inverter. Driving is possible. Furthermore, since the start timing is shifted in advance so that the priority machine can be externally set by the inverter, the operation order is not disturbed (such as when power is restored).

  Furthermore, since a retry operation at the time of failure is added, the failure state can be reliably detected.

  Furthermore, since the pressure sensor for detecting the load state and the pressure sensor for detecting the suction side pressure can be shared by the two inverters, it is simple and inexpensive.

CNU: control device, INV1, INV2: inverter, CU: control device, 4-1, 4-2: pump, 5-1, 5-2: electric motor, 9, 10: pressure sensor.

Claims (10)

In a water supply apparatus that supplies water with at least two or more pumps, each controlled by an inverter,
A first setting switching means for switching the setting of the inverter set as a starting machine for starting and performing pump control, as a starting machine for starting and performing pump control after the starting machine has stopped operating;
A second setting switching means for switching the setting of the inverter set as the subsequent machine as the preceding machine when the preceding machine is stopped after the start of the preceding machine;
When the starting machine is operated together with the latter machine,
During the subsequent machine to accelerate until reaching the set speed after the start of the operation requested by the starter motor, the starter motor performs discharge pressure constant control, then, the subsequent machine operated at a constant speed, the starter machine a parallel operation means for estimating constant end pressure control as common pressure becomes a predetermined target pressure on the pump discharge side without the a constant speed,
A water supply apparatus comprising:   The water supply apparatus according to claim 1, wherein when the starting machine and the succeeding machine are operated together by the parallel operation means, when the starting machine stops, the succeeding machine performs constant estimated terminal pressure control. Water supply device. In the water supply apparatus according to claim 1, comprising a failure detection means for detecting that the starting machine has failed,
A water supply apparatus characterized in that when the failure detection means detects a failure of a preceding machine, the operation is performed by the latter machine.   2. The water supply device according to claim 1, wherein the parallel operation unit operates the starter so that a pressure common to the pump discharge side becomes a constant value until the latter accelerates to the constant speed. Water supply device characterized by.   The water supply apparatus according to any one of claims 1 to 4, wherein when the starting machine and the succeeding machine are operated together by the parallel operation means, the starting machine is not more than a predetermined speed and is common to the pump discharge side. The water supply device is characterized in that the starting machine is stopped when the pressure of the water reaches a predetermined pressure or higher. In a control method of a water supply apparatus that supplies water with at least two or more pumps, each controlled by an inverter,
The inverter set as a starting machine for starting and controlling the pump first, after the starting machine has stopped operating, switching the setting as a starting machine for starting and controlling the pump later,
The inverter set as the starting machine, after the starting machine is started and the starting machine stops, the setting is switched as the starting machine,
When the starting machine and the following machine operate together,
During the subsequent machine to accelerate until reaching the set speed after the start of the operation requested by the starter motor, the starter motor performs discharge pressure constant control, then the starting motor is operated at a constant speed, the subsequent machine A control method for a water supply apparatus, wherein the terminal pressure constant control is performed so that a pressure common to the pump discharge side becomes a predetermined target pressure without setting a constant speed.   7. The water supply apparatus control method according to claim 6, wherein when the starting machine and the subsequent machine operate together, when the preceding machine stops, the terminal machine performs constant estimated terminal pressure control. Control method.   7. The method for controlling a water supply apparatus according to claim 6, wherein when the starter machine is detected to be out of order, operation is performed by the latter machine.   The control method of the water supply apparatus according to claim 6, wherein the starting machine is operated so that a pressure common to the pump discharge side becomes a constant value until the succeeding machine is accelerated to the constant speed. To control the water supply device.   In the control method of the water supply apparatus according to any one of claims 6 to 9, when both the starting machine and the following machine operate together, the starting machine has a predetermined speed or less, and a pressure common to the pump discharge side. A control method for a water supply apparatus, wherein the starting machine is stopped when the pressure exceeds a predetermined pressure.

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