JP3570880B2 - Power control module - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power control module suitable for operation control of a system including a variable-speed rotating machine such as a pump and a fan, and more particularly to an inverter device for controlling an operating speed of a rotating machine and a CPU for controlling the inverter device. The present invention relates to a power control module including an inverter control module equipped with elements and a sequence control module equipped with a CPU element that controls the operation of a system including a rotating machine or the like that operates at a variable speed by power supplied from an inverter device.
[0002]
[Prior art]
By using an inverter device that converts the frequency and voltage of a commercial AC power supply into an arbitrary frequency and voltage for a rotating machine such as a pump and a fan, it is widely performed to operate the rotating machine such as a pump and a fan at a variable speed. I have. Inverter devices can change the operating speed of the motor that drives the pumps and fans arbitrarily, so operating at the optimum operating speed corresponding to the load of the pumps and fans, etc., compared to operating at the rated speed Energy saving can be achieved.
[0003]
In addition, in various water supply devices, a pressure sensor is attached to the pump discharge side, and an operation speed signal is sent from the PI control unit to the inverter device so that the detected pressure signal matches the set pressure value. 2. Description of the Related Art A constant discharge pressure control operation for controlling an operation speed and keeping a discharge pressure of a pump constant has been performed. Further, an estimated terminal pressure constant control operation for controlling the supply water pressure at the end customer to be constant by performing an appropriate change of the pump discharge target pressure sequentially from the flow rate sensor or the operation speed is performed.
[0004]
In an air conditioner or the like, a temperature sensor is attached to the fan discharge side, and the operation speed of the fan is controlled by an inverter device from the PI control unit so that the temperature of air blown by the fan matches a predetermined temperature set value. It is known to perform a constant temperature control operation.
[0005]
When a variable speed pump or a variable speed fan having such an inverter device is incorporated in a water supply device or an air conditioner, various operation controls are required. For example, when used for a water supply device, the start / stop control of the variable speed pump is performed based on an operation / stop command from a control station located away from the pump. It is also necessary to display these operating conditions. In the case of automatic operation that keeps the discharge pressure constant, the signal of the pressure sensor provided at the pump discharge port is taken into the control device in the water supply device, and the rotation speed is controlled at a variable speed so that the discharge pressure is kept constant. There is a need to. Furthermore, when the amount of water supply, which is the load of the pump, becomes extremely small, the pump operates in a shut-off state, so water is accumulated in the pressure tank provided on the discharge port side of the pump, and the pump is stopped. It is also necessary to perform operation control such as performing.
[0006]
Therefore, when a variable speed pump provided with an inverter device is also incorporated in a water supply device and used, an operation control device as a water supply device is required, and the operation control device generally uses a CPU and a memory.
[0007]
An inverter device generally includes a converter unit including a rectifier circuit such as a diode module that rectifies AC power such as a commercial AC power supply, a capacitor unit that smoothes rectified AC power and stores the DC power as DC power, and a capacitor. And an inverter for inversely converting the DC power stored in the unit into AC power having a predetermined frequency and voltage. Generally, the converter unit includes an inrush current prevention circuit including a rush current prevention resistor, a magnet switch, or a thyristor. Further, the inverter unit is composed of a power element such as a power transistor and an IGBT. A driver circuit for driving the power element, a control circuit including a CPU and a memory for outputting an open / close signal of the power element to the driver circuit, a control power supply circuit for supplying a DC power supply such as +5 V to the control circuit, A protection circuit or the like for protecting the power element or the like from overvoltage or overcurrent is also required as a peripheral accessory circuit.
[0008]
By the way, a semiconductor manufacturer sells a power module for an inverter in which a power element of a converter section and an inverter section, a driver circuit of the inverter section, and a protection circuit related to the power element are housed in one package. Here, the protection circuit is, for example, a thermistor element that detects an excessive rise in the temperature of the power element. By connecting a capacitor to the power module and combining a driver circuit with a control circuit including a CPU and a memory for outputting an open / close signal of the power element of the inverter unit, the power module for the inverter can be operated. it can.
[0009]
The control circuit can form an AC power output of an arbitrary frequency and voltage in the inverter device by outputting, for example, a pulse width modulation (PWM) signal. In addition, a circuit board on which these control circuits are mounted is generally housed in a housing as a separate substrate from the inverter device. Cooling.
[0010]
In general, the housing is provided with an operation indicator so that the operating frequency and various alarms can be displayed. Further, an interface circuit to the outside of the housing is provided, so that an operation signal of the inverter device or an alarm signal when the protection circuit detects an abnormal state can be output from the outside. Such a conventional inverter device and its control device purchase various circuit components described above, arrange them on a plurality of circuit boards, and connect these with various connectors and the like.
[0011]
[Problems to be solved by the invention]
As described above, in the conventional inverter device and its control device, the above-described various components are arranged on a plurality of circuit boards, housed in a housing, and wired and connected by a connector or the like. In other words, it takes a lot of man-hours to assemble, wire, etc., the overall size of the inverter device cannot be reduced, and various components are packaged by molding resin sealing or the like, and these components are mounted on a circuit board. Since it is housed in the housing, the overall size is increased, and the cost for an extra package is also required, so that the manufacturing cost is increased as a whole.
[0012]
Further, as described above, since the control circuit of the inverter device is constituted by electronic components such as a CPU and a memory as the control device, if the inverter device is directly mounted on a casing of the pump, for example, the inverter device is cooled by a liquid handled by the pump and becomes There is a possibility that dew may condense on the connection portion of the device, and therefore, measures to prevent dew condensation, such as preventing moisture from entering or preventing cooling, are required. For this reason, the control device arranged in the housing must be placed in a different place from the pump and the like, and there is a problem that the size of the system is increased.
[0013]
The present invention has been made in view of the above circumstances, and can be used in a wide range of environments without causing problems such as dew condensation and the like, and can be used in an inverter device and its control device, and supplied by the inverter device. It is an object of the present invention to provide a control device for a rotating machine that can easily create a program for controlling the operation of a system including a rotating machine that operates at a variable speed with electric power.
[0014]
[Means for Solving the Problems]
One embodiment of the present invention provides:A power control module for supplying variable frequency power to the feedwater pump system,A power module equipped with a power element of a converter section and a power element of an inverter section,A sequence control module equipped with a CPU element for controlling the operation of the feedwater pump system,An inverter control module equipped with a CPU element is housed in a box-shaped container, the box-shaped container includes a copper plate on the bottom, the power module is fixed to the copper plate, and theSequence control module andAn inverter control module is mounted, and the power module andSequence control module andEach inverter control moduleDifferent kindsThe resin that is sealed with a resin and seals the power module has a low thermal conductivity,Sequence control module andA resin that seals the inverter control module is a power control module that has good moisture resistance..
[0015]
Accordingly, since the power device constituting the inverter device itself except for at least the capacitor and the control module including the CPU device for operating the inverter device are sealed in a box-shaped container, The structure can be made compact. In addition, this control device can be used in a system that handles water such as a variable speed water supply device by sealing hermetically with mold resin or the like, or under severe operating environment conditions such as fixing directly to a pump casing. It is possible to operate stably without problems such as dew condensation. Further, since the sequence control module has a system program, it is possible to easily produce an application program for controlling the operation of the system. As a result, for example, the operation control of the system including the variable speed water supply pump and the like and the control of the inverter can be performed without contradiction, and an application program that can respond to various installation sites can be constructed in a short time. Further, it is possible to flexibly cope with a change in the operating conditions and the like.
[0016]
Also,The present inventionOther aspects ofIn the inverter control module, in addition to the CPU element, a driver circuit, a protection circuit, an auxiliary power supply, and an electrically rewritable memory element are mounted..Thus, the power element of the inverter unit of the inverter device can be switched by the driver circuit, and the power element can be protected from overcurrent, overvoltage, abnormal temperature rise, and the like by the protection circuit. Also, various power supply voltages such as +5 V, +24 V, ± 15 V, etc. can be supplied to various semiconductor chips by the auxiliary power supply, thereby performing various control operations. Also, by providing an electrically rewritable memory element, the control of the inverter unit can be changed from, for example, a three-phase induction motor to a DC brushless motor or a stationary inverter device, thereby increasing the flexibility of the system. Can increase.
[0017]
Also,The present inventionOther aspects ofIn the sequence control module, in addition to the CPU element, a memory element, a communication element, and a clock element are mounted..As a result, E as a communication element and a memory element²By using an electrically rewritable device such as a PROM, the contents of the program can be rewritten from outside. Therefore, the operation control program of the system can be easily changed. In particular, by mounting the sequence control module detachably on the box-shaped container, debugging at the installation site becomes possible, and changing operation conditions, etc. Swift response is possible. In addition, by mounting a clock element, various timings that are the basis of operation control can be easily formed.
[0019]
Thereby, the power element is fixed to the copper plate, so that heat can be efficiently radiated. Further, since the resin for sealing the power module has a relatively low thermal conductivity, it is possible to prevent heat from the power module from being transmitted to the inverter control module or the sequence control module on which the CPU element is mounted. Therefore, the inverter device generating a large amount of heat and the CPU element that dislikes high temperature can be housed in a box-shaped container having a compact structure.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 shows a state in which an external capacitor is attached to a power control module according to an embodiment of the present invention. FIG. 2A is a top view thereof, and FIG. 2B is a side view thereof. This is not only the inverter device itself, but also serves as a control device for the inverter that forms a variable frequency and a voltage and a control device for controlling the operation of a system including a rotating machine that operates at a variable speed with the power supplied by the inverter. is there.
[0022]
In the control device 10, each module described below is housed in a box-shaped container 11, and is entirely sealed with a mold resin. The size of the box-shaped container 11 is about the size of a lunch box, and has a very small and compact structure. The lower end surface of the box-shaped container 11 is formed of a copper plate 21 so as to transfer heat generated by the power module to the outside.
[0023]
In the control device 10, a power module including a power element of a converter unit, a power element of the inverter unit, and a protection circuit and the like for the inverter unit are included. Further, as described above, the capacitor 12 is externally provided, and power of a variable frequency / variable voltage necessary for variable speed operation of the rotating machine is supplied to the rotating machine by combining the capacitor and the power module.
[0024]
Further, the control device 10 accommodates an inverter control module including a driver circuit for driving switching of a power element of the inverter unit, a CPU element, a memory element, an auxiliary power supply circuit, and the like. Further, a system control module having a CPU element for controlling the operation of a system including a rotating machine that operates at a variable speed by the power supplied from the inverter device is also housed in the control device 10. The terminals of the inverter control module and the sequence control module are electrically connected so that signals can be transmitted between the CPU elements.
[0025]
Various terminals and connectors are arranged on the upper end surface of the box-shaped container 11. Terminal 15 is a terminal for connecting a three-phase commercial AC power supply line (R, S, T), terminal 16 is a U, V, W phase terminal for supplying inverter output power, and various terminals such as a motor pump. Connected to rotating machines. The terminal 17 is a connection terminal of the capacitor, and is connected to the external substrate 13 on which the capacitor 12 is mounted. The connector 18 is a communication connector such as RS485, and is connected to a communication line from a central monitoring device or the like, so that signals can be exchanged with the outside. The connector 19 is connected to input / output lines for various digital signals and input / output lines for analog signals. The digital signal input Di is, for example, a system operation / stop command, and the digital signal output Do is, for example, an alarm output command. The analog signal input Ai is, for example, an output signal of a sensor, and the analog signal output Ao is, for example, an output signal of an inverter frequency.
[0026]
FIG. 3 is a diagram illustrating an example of the internal structure of the control device. The lower end surface of the box-shaped container 11 is a copper plate 21, on which a high-power diode element 23 constituting a converter unit of the inverter device and a power element 24 such as an IGBT and a power transistor constituting an inverter unit are fixed. A ceramic substrate 22 is provided. In addition, a thermistor element 25 is disposed in a portion where a power element such as an IGBT is disposed, so that a temperature rise of the power element can be detected. Although a large amount of heat is dissipated from these power elements 21 and 23, the heat can be satisfactorily dissipated through the ceramic substrate 22 and the copper plate 21. Note that the control device 10 may be disposed in, for example, a pump casing in the variable speed water supply pump system so that the copper plate 21 can be cooled using, for example, water supplied by the variable speed water supply pump system.
[0027]
A printed wiring board 27 on which an inverter control module is mounted is disposed in the middle of the box-shaped container 11, and various elements such as a CPU element 28 for inverter control are mounted thereon. Although not shown here, the driver circuit, E²A memory element such as a PROM or a RAM, an auxiliary power supply circuit for supplying power of +5 V, +24 V, ± 15 V or the like to various chips, a protection circuit, and the like are mounted. The board 27 on which these various control elements are mounted and the board 22 on which the lower power element is mounted are connected by a relay terminal 29 so that signals are transmitted to each other.
[0028]
A board 30 on which a sequence control module such as a CPU element for controlling the operation of the variable speed water supply pump system and the like is mounted in an upper stage inside the box-shaped container 11. On this substrate 30, in addition to the CPU element 31, E²Various control chips such as a memory element such as a PROM and a RAM, a communication element, and a clock element are mounted. The board 30 is supported by the pins 32 with respect to the lower board 27, and is connected so that signals can be transmitted to each other using a wiring cable.
[0029]
At least two types of resins A and B are used for sealing each module. Silicon resin having a relatively low thermal conductivity is used as the resin A for sealing the power module that dissipates a large amount of heat. This portion of the resin A is indicated by hatching in the figure. The upper substrates 27 and 30 are sealed with a resin B having good moisture resistance, such as epoxy resin. As a result, the power element is fixed to the copper plate, so that heat can be efficiently dissipated. In addition, the resin A for sealing the power module has a relatively low thermal conductivity and is difficult to conduct heat. The transmission to the inverter control module or the sequence control module on which the CPU element is mounted can be prevented. Therefore, the inverter device part generating a large amount of heat and the CPU element that dislikes high temperature can be housed together in a compact box-shaped container.
[0030]
In the above-described embodiment, the example in which the sequence control module is sealed in the box-shaped container with the mold resin has been described. However, the sequence control module can be detached to the outside of the container via a connector provided in the container. It may be attached to. Thereby, the program of the sequence control module can be changed at the installation site, and the convenience of the power control module is improved. Further, in the above-described embodiment, the example in which the inside of the box-shaped body is sealed with the mold resin is described. However, for applications that do not cause a problem such as dew condensation, the sealing with the mold resin is not necessarily required. . The form of the sealing should be appropriately changed to an optimum one according to the application.
[0031]
FIG. 4 shows a configuration of a circuit block of the control device. As described above, the power module shown in the figure is provided with the power element 24 such as the diode 23 and the IGBT. Here, the capacitor is externally attached, and its connection terminal is arranged at the upper end of the box-shaped container of the control device. Examples of the protection circuit 37 include an overcurrent detection circuit, an overvoltage detection circuit, and a circuit for detecting an excessive rise in power element temperature by a thermistor. These signals are transmitted to the inverter control CPU element 28 of the inverter control module. The inverter control module includes a driver circuit 40, and supplies a drive current such as a pulse width modulation signal to a base (gate) terminal of the power element 26 such as an IGBT.
[0032]
Further, the inverter control module includes an auxiliary power supply circuit 41, which is provided with a power supply capable of supplying a DC voltage such as + 5V for the power supply of the CPU element, + 24V for the interface, ± 15V for the input and output of analog signals. ing. In this case, a DC-DC converter converts the DC voltage of the inverter device into a power supply having these various DC voltages. Power is supplied from this auxiliary power supply to another module, for example, a CPU element 31 for operation control of a system such as a variable speed water supply device. Also, this power supply is provided by E²It is similarly supplied to various chips such as a PROM 42, a RAM 43, a clock chip 44, and a communication control chip 45 such as RS485. A communication element 45 such as RS485 is connected to the CPU element 31 and the external connector 18, and is capable of transmitting and receiving signals to and from a remote central control device or the like through a communication line. The timepiece element has a battery terminal 46, and a battery can be connected to the outside so that backup can be performed even during a power failure.
[0033]
Next, control contents of the inverter control CPU element 28 and the sequence control CPU element 31 will be described. The inverter control CPU element 28 receives a command for the output frequency and voltage of the inverter device and outputs a command signal for switching the power element 36 of the inverter unit to the driver circuit 40 so that the output frequency and voltage are obtained. The output frequency and voltage are formed using, for example, a pulse width modulation (PWM) signal, and an arbitrary output frequency and voltage are formed by calculating the number of output pulses from an input command. In addition to this, the inverter control CPU element 28 has a program specific to the inverter control operation such as a soft start function for realizing a gentle rise when the pump is started and a soft stop function for realizing a gentle fall when the pump is stopped. Have. Needless to say, a basic program is provided to start / stop the inverter output in response to a signal accompanying the start / stop of the pump.
[0034]
These programs are usually described in assembler language, and are stored in a ROM built in the CPU element 28. However, if the memory is E²It can be electrically rewritable, such as a PROM, and the contents of the program can be rewritten according to the situation at the installation site. This makes it possible to support other drive types such as DC brushless motors and static inverters. is there.
[0035]
The sequence control CPU element 31 performs an overall control operation of a system including a rotating machine that operates by receiving AC power supplied from the inverter. For example, it performs a control operation of a water supply system including a variable speed motor pump, a pump discharge pressure constant control for maintaining a constant supply water pressure, a terminal pressure constant control for maintaining a constant supply water pressure at a water pipe demand end, and a pump. It controls the number of operating units according to the load, issues an alarm when an abnormality occurs, and performs protective operations such as emergency stop.
[0036]
These control operations are performed by a program stored in a memory. The program is roughly divided into a system program and an application program, and the system is stored in a memory (ROM) built in the sequence control CPU element 31. Has a program. The system program is a program for operating the CPU in a language described in an application program, and includes, for example, a routine for four arithmetic operations, a routine for logical operation, a routine for PID (proportional-integral-derivative) control operation, and the like. The application program can easily describe the control operation as a sequence using a simple language such as a ladder language, for example, and describes the control operation of the pump water supply system, for example. Therefore, in a pump water supply system or the like, this CPU element 31 and E²All control operations such as the above-described constant pump discharge pressure control can be executed by the application program of the PROM 42.
[0037]
The description of the application program in the simple language is extremely easy to create as compared with the program in the assembler language, and various control operations can be described in a short time. In addition, emulation using a personal computer is possible, and debugging of the system is easy. The application program is an electrically rewritable E²It is preferable to store it in the PROM 42. For example, in a pump water supply system, operating conditions vary widely depending on the installation site, and it is necessary to rewrite a program to optimal control contents according to each site. Note that this rewriting can be executed externally via a communication line.However, by installing the sequence control module in a box-like container so that it can be detached and attached, it is easy to use a personal computer at the installation site. The program can be changed.
[0038]
In the above-described embodiment, an example is described in which the power module mounted with the power element of the inverter device, the inverter control module, and the sequence control module are mounted on independent boards, respectively. Needless to say, it may be mounted on a computer. E for electrically rewritable memory²Although the example of the PROM has been described, another type may be used. Also, an example of a water supply system using a variable speed pump by an inverter as a control target of the control device has been described. However, the gist of the present invention is not limited to these, and is not limited to a three-phase induction motor, and may be a DC brushless motor. The present invention can be widely applied to rotating machines whose operation is controlled by a variable speed device such as a motor, and a control device which controls the operation of these rotating machines. Further, the present invention can be applied to a system using a stationary inverter device such as an AC / DC converter that is not intended for a rotating machine.
[0039]
【The invention's effect】
As described above, according to the present invention, the inverter device itself, excluding the capacitor, the control device for operating the inverter device, and the operation control device of the system including the rotating machine and the like are box-shaped ultra-small. And provided in a sealed container. And since this control device is sealed with a mold resin, for example, even if it is directly fixed to the pump casing of a water handling system such as a variable speed water supply device, there is no problem such as dew condensation. Further, since the sequence control module has a system program, it is possible to easily produce an application program for controlling the operation of the system. As a result, an application program that can respond to various installation sites can be constructed in a short period of time, and it is possible to flexibly respond to changes in operating conditions and the like.
[Brief description of the drawings]
FIG. 1 is a perspective view of a control device according to an embodiment of the present invention.
2A is a plan view and FIG. 1B is a side view of FIG.
FIG. 3 is a diagram showing a cross section of a main part of FIG. 1;
FIG. 4 is an explanatory diagram illustrating a configuration of a circuit block of the control device in FIG. 1;
[Explanation of symbols]
10 Control device
11 Box-shaped container
12 Capacitor
15, 16, 17 terminals
18, 19 Connector
21 Ceramics substrate (power module)
23 Rectifier (diode)
24 Power element (IGBT)
27 Board (Inverter control module)
28, 31 CPU element
30 substrates (sequence control module)
40 Driver circuit
41 Auxiliary power supply circuit
42, 43 memory
44 Watch element
45 Communication control element

Claims (4)

A power control module for supplying variable frequency power to the feedwater pump system,
A power module equipped with a power element of a converter unit and a power element of an inverter unit, a sequence control module equipped with a CPU element for controlling the operation of the feedwater pump system, and an inverter control module equipped with a CPU element are box-shaped. Housed in a container,
The box-shaped container is provided with a copper plate at the bottom, the power module is fixed to the copper plate, and the sequence control module and the inverter control module are mounted thereon,
The power module and the sequence control module and the inverter control module are respectively sealed with different types of resins, the resin sealing the power module has a low thermal conductivity, and the sequence control module and the inverter control module are A power control module characterized in that the resin to be sealed has good moisture resistance. The inverter control module and the sequence control module are electrically connected so that signals can be exchanged with each other, and the sequence control module includes a system program, and includes an application program for controlling operation of the system . The power control module according to claim 1 , wherein the power control module is rewritable. Wherein the inverter control module, in addition to the power control module according to claim 1 or 2, and the driver circuit, and a protection circuit, characterized in that mounted an auxiliary power supply of the CPU element. 3. The power control module according to claim 1, wherein the sequence control module includes an electrically rewritable memory element and a communication element in addition to the CPU element. .

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