JP2001238490A - Control unit for a plurality of motors, power converter, inverter module and converter module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control unit which connects a plurality of motor drive circuit with a power source circuit and controls effectively a plurality of motors, and enable power control and high efficiency operation of the motor control system as a whole by using communication means of network or the like. SOLUTION: A plurality of inventers 2, 4, 6, capable of rotational speed control of motors 3, 5, 7 are connected with a converter 1 capable of controlling a DC voltage, and the DC voltage is changed from a conduction ratio of each of the inverters, motor loads, etc. Communication means of a network or the like is installed for the converter, and the inverters, working electrical energy, input current, output torque, etc., are calculated, and controlling is done by a high order control unit, so that power control, failure diagnosis, etc., are enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a motor control device for simultaneously controlling a plurality of motors using a converter and an inverter.

[0002]

2. Description of the Related Art As a conventional motor control device, an input current is converted into a sinusoidal alternating current using an inverter,
The motor speed is controlled by WM (Pulse Width Modulation) control, and the converter (AC-DC conversion circuit), which is the power supply circuit of the inverter, converts the DC voltage using a boost chopper that can improve the power factor of the power supply. PAM
(Pulse Amplitude Modulation) is known to control the speed of a motor (for example, see Japanese Patent Application Laid-Open No.
No. 10968, JP-A-59-198897,
JP-A-59-181973).

In this system, at low speed, the motor speed is controlled by PWM control, and at high speed, the motor speed is controlled by using DC voltage control (PAM control) of a power supply circuit. Further, when the control is switched to the PAM control, there are a method of changing the duty ratio of the motor drive circuit to 100%, a method of maintaining the duty ratio at the time of the switching, and a method of setting a fixed duty ratio pattern. .

A converter 1 for converting AC to DC
As an inverter device in which a plurality of inverters having a motor rotation speed control function are connected to each other,
Japanese Unexamined Patent Publication No. 155283/1995 and Japanese Unexamined Patent Publication No. 10-225163.

In the apparatus described in Japanese Patent Application Laid-Open No. H10-155283, a converter integrated with a rectifier circuit and rush current prevention, a control circuit for controlling the number of rotations of a motor, and signal exchange with the outside are disclosed. An inverter having an interface circuit to be performed is modularized, and a plurality of inverter modules are connected to one converter module, thereby sharing the converter module.

Japanese Patent Application Laid-Open No. 10-225163 discloses that a converter having a function of controlling a DC voltage is connected to a plurality of inverters capable of vector control of an induction motor, and the induction motor rotates at a command speed or less for a predetermined time. if you did this,
A technique for preventing the induction motor from burning by lowering the DC voltage command of the converter is disclosed.

[0007]

In the above-mentioned prior art, the system using both PWM control and PAM control has a one-to-one correspondence between a converter and an inverter. Considering control of a plurality of motors using the above technology, as shown in FIG. 4, a motor control device (1) corresponding to a plurality of motors is used.
A plurality of devices each having a one-to-one converter and an inverter) are prepared, and these motor control devices are connected to a power supply.

According to such a conventional system, a system using hundreds or thousands of motor control devices (such a system is realized in a system in which the output of each motor control device is relatively small). In this case, the number of converters to be a DC power supply circuit is required by the number thereof, and the cost increases. Further, since there is a fixed loss of the DC power supply circuit itself (a loss generated regardless of the magnitude of the output), the system efficiency is reduced.

Japanese Patent Application Laid-Open No. H10-155283 discloses a technique in which a converter and an inverter are modularized, and a plurality of inverter modules are connected to one converter module to share the converter module. However, the inverter module and the converter module operate independently, and no consideration is given to the fact that the inverter module and the converter module cooperate to control the rotation of the motor.

An interface circuit built in the inverter module is a terminal for rewriting a speed command and a memory to the inverter control circuit, and exchanges internal information of the inverter with a higher-level control device and a converter. There is no communication means, and no technique for improving the motor control performance by such communication has been disclosed.

Japanese Patent Application Laid-Open No. 10-225163 discloses a technique of detecting information on the number of revolutions of a motor connected to each inverter from a plurality of inverters and changing a control state according to the information. The purpose of this is to protect the burnout of steel.

More specifically, when the rotation speed of the motor is lower than the rotation speed command for a certain period of time, the DC voltage command is switched and reduced to prevent burnout.

Also in this conventional example, the rotation speed of the motor is controlled by an inverter, and the converter is used as a power supply source to the inverter, and there is no idea of controlling the rotation speed by the converter.

That is, these prior arts do not consider performing PAM control on a plurality of connected motors, and cannot always supply a desired DC voltage to an inverter.

An object of the present invention is to provide a system in which a plurality of motor drive circuits (inverters) are connected to one power supply circuit (converter), and even if one converter is used, status signals of a plurality of inverters (motor internal information) Accordingly, it is an object of the present invention to provide a motor control device that enables PAM control of a converter by totally considering these state signals and efficiently controls a plurality of motors.

Another object of the present invention is to provide a motor control device that enables power control and high-efficiency operation of the entire system by connecting a power supply circuit and a plurality of motor drive circuits by a communication means such as a network.

[0017]

Means for Solving the Problems In order to achieve the above object, basically, the following means for solving the problems are proposed.

That is, a plurality of inverters for controlling the rotation speed of the motor are connected to one converter capable of controlling the DC voltage, and the inverters control the speed of each motor (PWM control). The internal information such as the duty ratio of the motor and the motor load (inverter status signal) is captured via the communication means, and the DC voltage of the converter is controlled as necessary based on the status signal, so that the rotational speed of the plurality of motors is controlled. Was set to be controllable (PAM control).

Also, a communication means is provided in the converter and the inverter, a higher-level control device for collectively controlling the detection values detected inside the converter and the inverter is provided, and the converter and the inverter are controlled in accordance with a control signal from the higher-level control device. Suggest.

Further, a module is provided in which the inverter and the converter are provided with communication means for communicating with each other through a network, and the inverter and the converter are integrated with the communication means.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is an overall configuration diagram of a motor control device according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a converter for converting AC power into DC, which is a step-up chopper type circuit for simultaneously improving the power factor of the power and controlling the DC voltage.

A plurality of inverters 2, 4, 6 capable of controlling the rotation speed of the motor are connected to the converter 1 via a DC power supply line. Motors 3, 5, and 7 (motors of various uses are conceivable, but a motor for a compressor is exemplified here) to be drive-controlled is connected to each of the inverters 2, 4, and 6, respectively. The rotation speed of the motor is controlled by PWM control by corresponding inverters.

This converter 1 and a plurality of inverters 2
4, 6 and the control circuit 8 are connected via a network (internal network).

The control circuit 8 outputs a DC voltage command value to the converter 1 via the network,
A rotation speed command value (speed command value) is output to 4 and 6, and
It has an arithmetic function of inputting a DC voltage value of the converter and a status signal of the inverter (for example, input current value, inverter duty ratio) and calculating a DC voltage value based on the input.

The control circuit 8 is also connected to an external network so that a motor speed command and the like can be set and changed from the outside.

FIG. 2 shows a circuit configuration of the converter 1.

The converter 1 controls the switching operation of the full-wave rectifier circuit 10, the boost chopper circuit 11, the smoothing capacitor 12, and the boost chopper circuit in order to convert the AC power into DC, thereby improving the power factor of the power. At the same time, it comprises a converter control circuit 13 for controlling the DC voltage to a predetermined value and a communication circuit 14 for communicating with the control circuit 8 via a network. The communication circuit 14 is a signal conversion circuit that exchanges signals between the converter control circuit 13 and the higher-level control circuit 8.

FIG. 3 shows a circuit configuration of the inverters 2, 4, and 6.

The inverters 2, 4, and 6 are composed of an inverter main circuit 21 comprising a switching element and a diode, and a switching element which is connected to the motors 3, 5, 7 according to the rotor position.
An inverter control circuit 22 that drives the motor with a WM signal to control the rotation speed of the motor communicates with the control circuit 8 via a network, and transmits a rotation speed command value to the inverter control circuit 22 according to a control signal from the control circuit 8. And a communication circuit 23 for outputting.

The communication circuit 23 is a signal conversion circuit for exchanging signals between the inverter control circuit 22 and the control circuit 8, and outputs the duty ratio of the PWM signal output from the inverter control circuit 22 to the control circuit 8. ing.

The components of the converter and the inverter shown in FIGS. 2 and 3 can be reduced in size and cost by integrating them into a module.

The converter control circuit 13 shown in FIG.
If a microcomputer having a network communication function is used for the inverter control circuit 22 shown in FIG. 3 and FIG. 3, the functions of the communication circuits 14 and 23 can be realized by the communication function of the microcomputer.

The control circuit 8 outputs respective rotational speed command values to a plurality of inverters 2, 4, and 6 via a network (internal network) in accordance with a command signal input from an external network. In addition, each inverter 2,
The duty ratios 4 and 6 are fetched via a network, a DC voltage value required for motor speed control is calculated based on these values, and the voltage command value is output to the converter 1 via the network.

FIG. 5 shows a DC voltage command changing method performed in the control circuit 8.

In step (S1), the duty ratio of each of the inverters 2, 4, and 6 is read via the network.
Next, the process proceeds to (S2), where the maximum value is selected from the read flow rates.

In (S3), the selected maximum value of the duty ratio is compared with a preset comparison value D1, and if the maximum value of the duty ratio is larger, the process proceeds to (S4) and the DC voltage command value is set. Is increased by a preset size. Otherwise, the process proceeds to (S5), and again compares the conduction ratio maximum value with the comparison value D2. If the comparison value D2 is large, the process proceeds to (S6) to reduce the DC voltage command value to a predetermined value. To decrease.

The DC voltage command value obtained here is output to converter 1 via a network.

The above method uses the maximum duty ratio value and the comparison values D1, D
2 was compared, but each inverter 2, 4, 6
May be selected and the DC voltage command value may be determined based on each value. FIG. 6 shows the algorithm.

The difference from FIG. 5 is that the step (S2
') And (S5'). To explain only this part, in (S2 '), the maximum value and the minimum value are selected from the read conduction ratio.

Next, in (S3), the maximum value of the conduction ratio is compared with the comparison value D1, and if the maximum value is larger, (S3)
Proceed to 4) to increase the DC voltage command value.

Otherwise, the process proceeds to (S5 '), where the minimum value of the conduction ratio is compared with the comparison value D3. If the minimum value is smaller, the process proceeds to (S6) to decrease the DC voltage command value.

By using the present algorithm, the duty ratio of each of the inverters 2, 4, and 6 falls between D1 and D3, and efficient motor control can be performed as a whole.

As described above, according to the present embodiment, a plurality of inverters and one converter allow PWM to be applied to a plurality of motors.
In addition to control, speed control by PAM control becomes possible,
The fixed loss can be reduced and a highly efficient motor control device can be realized as compared with a method in which a converter is prepared for each inverter.

Therefore, for example, a great effect can be expected in a system having a small output per unit and a large number of motors, a fan motor control device in a building or the like.

In the above embodiment, the duty ratio is exemplified as the status signal of the inverter. In addition, the duty ratio of the inverter, the input current, the output current, the output power, the motor speed, the motor load, At least one of the powers may be used.

The control circuit 8 controls each of the inverters 2 and
The input current flowing into each of the converters 4 and 6 is detected, and the load of each motor is estimated (calculated) from the input current value, the DC voltage value of the converter 1 and the motor speed, and the optimum DC voltage value of the converter 1 is calculated. May be.

FIG. 7 shows the relationship between the converter DC voltage and the inverter duty ratio with respect to the motor speed when the motor control of the above embodiment is executed. This figure shows a state under the condition that the load torque is constant.

FIG. 9 is a diagram when the algorithm shown in FIG. 5 is used. As shown in the figure, as the motor rotation speed increases, the duty ratio of the inverter 2 having the largest load is selected from the inverters 2, 4, and 6, and the duty ratio becomes D.
When the rotational speed becomes one or more, the control shifts from the PWM control to the PAM control, and the DC voltage of the converter 1 is controlled stepwise.
Here, if the increase / decrease range of the DC voltage is made small, the DC voltage changes linearly from the stepped shape, and the conduction ratio also changes linearly.

FIG. 8 shows an overall configuration diagram of a second embodiment of a motor control device that performs the same operation as described above. The difference between this configuration diagram and the first embodiment is that the control circuit 8 is not provided outside the converter and the inverter. In the case of the present embodiment, it is a configuration diagram when the function (circuit) performed by the control circuit 8 is incorporated in a converter 100 (corresponding to the converter 1 in FIG. 1).

In this case, the data communicated through the network is only the duty ratio values of the inverters 2, 4, and 6. Data (DC current value) in converter 100 is processed in the converter.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

FIG. 9 is an overall configuration diagram of a motor control device according to the third embodiment. This embodiment has substantially the same configuration as the embodiment of FIG. 8 (that is, a circuit for controlling the DC voltage of the converter based on the state signals of the inverters 2, 4, and 6 is incorporated in the module of the converter 30). ,
The difference is that the converter 30 and the inverters 2, 4,
6 is connected not by a network but by a signal line shown by a broken line, and current detectors 41, 42, 43 for detecting currents flowing into the inverters 2, 4, 6 are provided on the power lines of the inverters. is there.

The converter 30 and the inverters 2, 4, 6
, A speed command value from a host is input through a signal line. The speed command value is provided individually for each inverter, and it is possible to provide different values for each. Also, the converter 30
The current value flowing into each of the inverters 2, 4, 6 is detected via current detectors 41, 42, 43.

FIG. 10 shows an internal configuration diagram of converter 30. The difference from FIG. 2 is that the communication circuit 14 is not provided, and a DC voltage command circuit 15 is added instead.

The DC voltage command circuit 15 receives the DC voltage value detected inside the converter 30, the speed command value from the host, and the input current values of the inverters 2, 4, 6. And the converter control circuit 13
Is determined (calculated).

FIG. 11 shows a DC voltage command value changing method performed by the DC voltage command circuit 15. In (S1), the DC voltage value, the rotational speed command value of each of the inverters 2, 4, and 6, and the input current value are read.
The outputs 4 and 6 are calculated from the input current value and the DC voltage value.

Here, the output is obtained by multiplying the input current value by the DC voltage value. Originally, it is necessary to multiply the coefficient in consideration of the efficiency of the inverter, but it is omitted here.

Next, in (S3), a DC voltage value required by each of the inverters 2, 4, and 6 is obtained from the calculated outputs and the rotational speed command value, and the value is output as a DC voltage command value.

Here, the required DC voltage value is obtained by preparing a table from values previously obtained by measurement or the like and searching for the table.

Here, the value of the DC voltage required for the motor speed control was obtained from the rotation speed command value and the actual output.
The current load torque may be estimated from the actual rotation speed and the actual output value, and the DC voltage value required to control the rotation speed to the rotation speed command value may be calculated.

When the above embodiment is used, the DC voltage value of the converter 30 with respect to the motor speed and the inverters 2 and
FIG. 12 shows the operation at the conduction ratios of 4 and 6. This figure shows the condition under the condition that the load torque is constant as in FIG.

Although this figure shows a case where the rotational speed command is also gradually changing, smooth control can be performed by shortening the control cycle (calculation cycle).

Next, a fourth embodiment will be described with reference to FIG. FIG. 13 shows the overall configuration of the fourth embodiment, which uses a DC voltage command circuit 13 provided in a converter 40 as in the third embodiment, and uses a network as in the first embodiment. This is the case where is used. The loads of the motors 3, 5, and 7 are air conditioners (hereinafter, referred to as air conditioners).
(Abbreviated as air conditioner) and an indoor / outdoor fan. Basically nothing changes.

In the case of this circuit, the control circuit 80
0 and connected to an external network. The external network may be a home network or the like.

If the home network is connected to a higher-level device monitoring the power consumption in the home by using the home network, if the power usage in the home is likely to exceed the allowable value, the output of the air conditioner is automatically output. A system can be constructed that suppresses noise.

FIGS. 14 and 15 show the internal configuration diagrams (circuit diagrams) of the converter 40 and the inverters 50, 60 and 70 used in the embodiment of FIG. This figure corresponds to FIGS.
And a configuration in which a detection circuit for detecting a used current is built in each circuit.
Naturally, the detected current value is passed over a network via a communication circuit.

By converting the converter and the inverter into a module and connecting them with a network, a converter and an inverter system can be easily constructed, and the converter and the inverter system operate independently by determining the DC voltage value from the state of the inverter. Is possible.

FIGS. 16 to 18 relate to a fifth embodiment of the present invention, and illustrate a home refrigerator, an air conditioner, and a microwave oven as power control objects of the power converter. A method of suppressing the output of the air conditioner when the allowable value is likely to be exceeded will be described.

FIG. 16 shows home appliances 201, 202, and 2
3 shows a state in which a higher-level control device 200 that grasps the power consumption of each of the electric appliances 201, 202, and 203 and controls the power consumption is connected via a network.

Each of the electric appliances 201, 202, and 203 outputs the power consumption to the host controller 200 via the network. Here, the same effect can be obtained by connecting a power meter to the input side of each appliance and transmitting the power consumption from the power meter to the host controller 200.

The host control device 200 is connected to a telephone line, and can control each electric appliance from outside. In this case, it is necessary to have a structure in which each electric appliance can be turned on / off by a signal of the network.

As shown in FIG. 17, the upper-level control device 200 determines that each of the electric appliances 201, 202, 2 in (S1).
In step S2, the total power in the home and which device currently uses the most power are calculated.

In (S3), the allowable power value, which is the maximum amount of power that can be used by the home, is compared with the current total power, and if the total power is about to exceed the allowable power, in other words, the total power is When approaching the electric energy, the process proceeds to (S4), and outputs the electric power consumption suppression command signal and the set electric energy of the device.

Here, the power usage suppression command signal and the set power amount are output to all the electric appliances 201, 202 and 203, a method of outputting only to the maximum electric power using device, and a device of lower priority. A method is conceivable. Here, it is assumed that the air conditioner has been output to an air conditioner with a low priority.

When the power consumption suppression command signal and the set power amount are output, air conditioner 202 receives the signals, and control circuit 80 in the air conditioner performs the operation shown in FIG.

The power control circuit in the control circuit 80 is shown in FIG.
In step (S1), each of the inverters 50, 6
0, 70 and the output from the converter 40 are read, the electric power used in the entire air conditioner is calculated, and the result is output to the network in (S2). The output power consumption is read by the host controller 200.

Next, in (S3), the host controller 20
From 0, it is confirmed whether the power consumption suppression command signal and the set power amount have been output to the air conditioner. If the power consumption suppression command signal and the set power amount have been output, go to (S5).
If not, the process proceeds to (S4).

In (S4), the rotation speed is controlled in accordance with a command from a remote controller which is a normal air conditioner control. In the case of (S5), power suppression control is performed.

The power suppression control is a method of controlling the power consumption of the air conditioner to the set power output from the host controller 200. Specifically, the rotation speed command value is reduced to reduce the used power to the set power. Control.

When the rotational speed command value changes, converter 40 and inverters 50, 60, and 70 operate accordingly.

As described above, it is possible to maximize the capability within the range of the permissible electric power in the home, and to perform the operation control of the electric appliance with high efficiency.

Although the above description is for a home system, FIG. 19 shows an embodiment in which the present invention is applied to an air conditioning fan control system for a clean room or a building.

FIG. 19 shows a configuration in which three units of fan control units 301, 302, 303 equivalent to those described in the first embodiment are used.
2, 303 are connected to each phase of the three-phase power supply. By connecting the power supply lines in this way, three-phase balance is ensured.

The host controller 300 is connected to each unit via a network, and monitors the current and voltage of the three-phase power supply.

As shown in FIG. 19, each fan control unit is connected via a network, and by grasping the power consumption and output torque of each fan, power control and failure diagnosis of each fan or clogging of a filter can be performed. Detection can be performed, and each fan control circuit can perform efficient motor control.

[0088]

According to the present invention, speed control by PAM control in addition to PWM control can be performed for a plurality of motors by a plurality of inverters and one converter, and a converter is prepared for each inverter. In addition, the fixed loss can be reduced, and a highly efficient motor control device can be realized.

Therefore, for example, a great effect can be expected in a system having a small output per unit and a large number of motors, a fan motor control device in a building or the like.

Further, by providing communication means such as a network in the converter and the inverter, calculating the power consumption, the input current, the output torque and the like and controlling them by a higher-level control device, it is possible to perform power control, failure diagnosis and the like. .

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a motor control device according to a first embodiment of the present invention.

FIG. 2 is an internal configuration diagram of a converter used in the first embodiment.

FIG. 3 is an internal configuration diagram of the inverter used in the first embodiment.

FIG. 4 is an overall configuration diagram of a motor control device according to a conventional technique.

FIG. 5 is a flowchart showing a DC voltage command changing method according to the first embodiment.

FIG. 6 is a flowchart showing another example of the DC voltage command changing method according to the first embodiment.

FIG. 7 is an operation explanatory diagram according to the first embodiment.

FIG. 8 is an overall configuration diagram of a motor control device according to a second embodiment of the present invention.

FIG. 9 is an overall configuration diagram of a motor control device according to a third embodiment of the present invention.

FIG. 10 is a configuration diagram of a converter used in the third embodiment.

FIG. 11 is a flowchart showing a DC voltage command changing method according to the third embodiment.

FIG. 12 is an operation explanatory diagram according to the third embodiment.

FIG. 13 is an overall configuration diagram of an air conditioner control device according to a fourth embodiment of the present invention.

FIG. 14 is a configuration diagram of a converter used in the fourth embodiment.

FIG. 15 is a configuration diagram of an inverter used in the fourth embodiment.

FIG. 16 is a configuration diagram of a home appliance motor control device according to a fifth embodiment of the present invention.

FIG. 17 is a flowchart showing a domestic power control method according to the fifth embodiment.

FIG. 18 shows a power control method in an air conditioner according to another embodiment of the present invention.

FIG. 19 is an overall configuration diagram of a motor control device according to a sixth embodiment of the present invention.

[Explanation of symbols]

1, 30, 40, 100 ... converter, 2, 4, 6, 5
0, 60, 70 ... inverter, 8, 80 ... control circuit, 2
00, 300: Host controller, 3, 5, 7 ... Motor, 1
3 ... Converter control circuit, 14, 23 ... Communication circuit, 15
... DC voltage command circuit, 21 ... Inverter main circuit, 22 ...
Inverter control circuit, 301, 302, 303 ... Motor control device unit, 90 ... Remote control.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Kazuo Tahara 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Research Laboratory, Hitachi Ltd. 5G053 DA03 EB01 FA04 5H007 AA06 BB06 CB02 CB05 CC03 CC09 DA06 DB12 DC02 EA01 EA02 5H572 AA11 BB02 BB07 CC05 DD02 GG10 HB02 HB09 HC01 HC07 JJ03 JJ26 KK05 LL22 LL50

Claims (15)

[Claims] An inverter capable of controlling the rotation speed of a motor is connected to one converter capable of converting an AC power supply to a DC power and controlling a DC voltage, and the respective inverters control the speed of each motor. Means for controlling the rotational speeds of the plurality of motors by capturing the state signals of the inverters via communication means and controlling the DC voltage of the converter based on the state signals. Control device for multiple motors. 2. The status signals of the converter and the inverter are input to a higher-level control device via communication means, and the higher-level control device determines a DC voltage value of the converter based on the status signals of the plurality of inverters. 2. The control device for a plurality of motors according to claim 1, wherein the command value is output. 3. The converter module receives communication means and status signals of a plurality of inverters via the communication means, determines a DC voltage of the converter based on the status signals, and outputs a control command. The control device for a plurality of motors according to claim 1, further comprising a control circuit that performs the control. 4. The control of the DC voltage of the converter is performed based on a state signal of an inverter having the largest load among signals taken from a plurality of inverters, and is executed based on the selected state signal. The control device for a plurality of motors according to any one of claims 1 to 3. 5. The control device for a plurality of motors according to claim 1, wherein a network is used for communication between the converter and each of the inverters. 6. An arithmetic unit for detecting an input current flowing into each of the inverters and calculating a required DC voltage value from the input current value, a DC voltage value of the converter, and a motor speed. A control device for a plurality of motors according to any one of claims 1 to 5. 7. The method according to claim 1, wherein at least one of a duty ratio of an inverter, an input current, an output current, an output power, a motor speed, a motor load, and power consumption is used as the status signal. 2. The control device for a plurality of motors according to claim 1. 8. A lower control device capable of individually controlling the rotation speeds of a plurality of motors, and a higher control device for controlling these lower control devices are connected via communication means, and said higher control device is connected to said lower control device. The device is configured to input the internal information of the lower motor control device via the communication means, to collect these input values and output a higher control command to the lower control device. Control device for multiple motors. 9. The internal information of the lower-level control device is the power consumption of each motor, and the higher-level control device does not exceed a predetermined sum of the power consumption input from the plurality of lower-level control devices. 9. The control device for a plurality of motors according to claim 8, wherein the control command is output to the lower control device. 10. A converter having a function of converting AC to DC and controlling a DC voltage, and an inverter having a control function of reversely converting the DC voltage to an AC voltage having an arbitrary frequency. Communicate with each other or with an external control device. 11. A communication circuit having a function of inputting a rotation speed command signal from the outside and transmitting internal information of the inverter to the outside is connected to an inverter circuit having a motor rotation speed control function. And an inverter module in which the communication circuit is installed and integrated on the same substrate. 12. A communication circuit having a function of communicating with the outside is connected to a converter circuit for converting AC power to DC power, and the converter circuit and the communication circuit are installed and integrated on the same substrate. And a converter module. 13. A converter circuit having a function of controlling a DC voltage, a communication circuit having a communication function with the outside connected to the converter circuit, and the converter circuit and the communication circuit are installed and integrated on the same substrate. Converter module to do. 14. An inverter module for controlling the rotation speed of a motor using a microcomputer,
The microcomputer has a communication function using a network, controls the rotation speed of the motor in accordance with a command signal from the network, and can output a control state signal of the inverter to the outside through the network. Inverter module. 15. In a converter for power conversion, communication means for receiving status signals from a plurality of inverters,
A converter module including a DC voltage control circuit and a DC voltage command circuit for determining a DC voltage command value of the converter itself based on inverter status signals sent from the plurality of inverters.