WO2012066939A1

WO2012066939A1 - Power control device and power control system

Info

Publication number: WO2012066939A1
Application number: PCT/JP2011/075381
Authority: WO
Inventors: 洋平丹野; 山崎　勝
Original assignee: 株式会社日立製作所
Priority date: 2010-11-18
Filing date: 2011-11-04
Publication date: 2012-05-24

Abstract

The purpose of the present invention is to provide a power control device that can supply a suitable amount of power to an electric motor. This power control device chronologically estimates the torque generated in an electric motor, and, on the basis of the estimation results, chronologically estimates the power required for driving the electric motor (see FIG. 1).

Description

Power control device, power control system

The present invention relates to a technique for controlling electric power supplied to a mechanical system including an electric motor.

In the industrial machine field such as press machines and injection molding machines, the hydraulic drive unit is being electrified in order to achieve energy saving and high precision control. In order to continuously operate an electric machine system in a normal state, a technique for supplying an appropriate amount of electric power to the electric motor at any time is necessary. In order to realize this, a technique for estimating the amount of electric power necessary to drive the electric motor and adjusting the electric power with an inverter in the mechanical system based on the estimation result is required.

In the following Patent Document 1, the torque estimation unit estimates the torque generated in the motor based on the U-phase current and V-phase current measured by the current sensor, and controls the inverter to rotate the motor at a desired rotational speed. Yes.

JP 2009-268268 A

In the above-mentioned Patent Document 1, the motor torque at that time is estimated using an actual measurement value such as a motor current, and electric power is supplied or charged in accordance with the estimation result. However, since the control is based on instantaneous measured values, depending on the load fluctuation state, there is a possibility that charging is not in time and power is insufficient, and the motor cannot perform a desired operation.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a power control apparatus capable of supplying an appropriate amount of power to an electric motor.

The power control apparatus according to the present invention estimates torque generated in the electric motor in time series, and estimates electric power necessary for driving the electric motor in time series based on the estimation result.

Since the power control apparatus according to the present invention estimates the power to be supplied to the electric motor in time series, the electric power necessary for causing the electric motor to perform a desired operation can be prepared in advance. Thereby, possibility that the electric power which drives an electric motor will run short can be reduced.

2 is a functional block diagram of the power control apparatus 100 according to the first embodiment. FIG. It is an internal block diagram of the model estimator 110, the power estimator 120, and the inverter 130. FIG. 6 is a functional block diagram of a power control apparatus 100 according to a third embodiment. FIG. 10 is a functional block diagram of a power control apparatus 100 according to a fourth embodiment. It is a block diagram of the

power control systems

1000a and 1000b which concern on Embodiment 5. FIG. It is a block diagram of the

power control systems

1000a and 1000b which concern on Embodiment 6. FIG.

<Embodiment 1>
FIG. 1 is a functional block diagram of a power control apparatus 100 according to Embodiment 1 of the present invention. The power control apparatus 100 is an apparatus that controls power supplied to the mechanical system 200, and includes a model estimator 110, a power estimator 120, and an inverter 130.

The machine system 200 is a system having a machine work function performed by, for example, an industrial machine, and includes a mechanism unit 202 that performs the machine work and an electric motor 201 that drives the mechanism unit 202.

Sensor 301 measures torque T generated in electric motor 201 and angular velocity ω of electric motor 201 and outputs the measured value 303 to model estimator 110. The torque T generated in the electric motor 201 can be obtained by measuring the current flowing through the electric motor 201, for example. The sensor 302 measures the displacement z and the load F of the mechanism unit 302 and outputs the measured value 303 to the model estimator 110. The

sensors

301 and 302 can be installed inside the motor 201 or the mechanism unit 202 or on the housing surface.

The model estimator 110 uses the measured value 303 to construct a torque estimation model 111 that estimates the torque T generated in the electric motor 201 in time series. Here, considering that the power estimator 120 outputs the angular velocity command value of the electric motor 201, the torque estimation model 111 is constructed as a function of the angular velocity of the electric motor 201. However, the torque T generated in the electric motor 201 is The model is not limited to this as long as it can be estimated as a series. Further, the measurement value 303 used for constructing the torque estimation model 111 is not limited to the above-described one, and it is sufficient that a model that can estimate the torque T generated in the electric motor 201 in time series can be constructed.

The model estimator 110 updates the torque estimation model 111 while acquiring the latest measured value 303 as needed. Thereby, it is possible to provide the torque estimation model 111 with always high estimation accuracy. When the load fluctuation of the mechanical system 200 is small, the torque estimation model 111 may be constructed using only the measured value 303 during a certain period (for example, at the time of startup), and the model may be continuously used thereafter.

As a technique for the model estimator 110 to construct the torque estimation model 111, any known technique can be used. As an example, a technique used in the fields of multivariate analysis, multiple regression analysis, system identification, and the like. Is mentioned.

If the basic configuration of the torque estimation model 111 is stored in advance in the model estimator 110 in the form of a calculation program or the like, the torque estimation calculation can be speeded up. For example, it is assumed that a torque estimation model 111 shown in the following (Equation 1) is constructed based on the energy conservation law in the mechanical system 200.
T = A ₁ · f ₁ (ω) + A ₂ · f ₂ (ω, z, F) + A ₃ · f ₃ (ω, z) (Formula 1)

In this case, the

sensors

301 and 302 first measure the torque T, the angular velocity ω, the displacement z, and the load F, which are state quantities included in (Equation 1), and output them to the model estimator 110. The model estimator 110 estimates each coefficient A ₁ , A ₂ , A ₃ of (Equation 1) by a technique such as multiple regression analysis. The torque T can be estimated by applying the coefficients A ₁ , A ₂ , A ₃ , the command value of ω, and the measured values of z and F to (Equation 1).

On the other hand, when the structure of the mechanical system 200 is a black box and the model structure cannot be grasped in advance, the torque estimation model 111 similar to (Equation 1) is analyzed by analyzing each measured value using the system identification method. Can be built. After the torque estimation model 111 is constructed, an unknown coefficient can be estimated by a technique such as multiple regression analysis to obtain a final torque estimation model 111.

The power estimator 120 inputs the angular velocity command value ω _t2 at the future time t2 to the torque estimation model 111 constructed by the model estimator 110. In response to this, the torque estimation model 111 returns the estimated torque T _t2 of the electric motor 201 at the future time t2. Electric power estimator 120 estimates electric power P _t2 required by electric motor 201 at future time t2 using estimated torque T _t2 , and notifies inverter 130 of it.

The inverter 130 converts the power supplied from the power source 400 into AC power having a desired frequency and supplies it to the electric motor 201. The inverter 130 includes a capacitor 131 that stores electric power. Based on the estimated power P _t2 notified from the power estimator 120, the inverter 130 stores in the capacitor 131 enough power to supply the power P _t2 to the electric motor 201 at a future time t2. If the power is insufficient at the time t2, the power stored in the capacitor 131 is released and supplied to the electric motor 201.

The inverter 130 may include a controller that controls its own operation, or the control operation may be delegated to the power estimator 120. When the power estimator 120 controls the operation of the inverter 130, the estimated power P _t2 notified from the power estimator 120 to the inverter 130 is actually a switching element drive command for performing an equivalent operation. When inverter 130 controls its own operation, only the value of estimated power P _t2 may be notified to inverter 130.

FIG. 2 is an internal configuration diagram of the model estimator 110, the power estimator 120, and the inverter 130. Hereinafter, the configuration of each unit will be described.

The model estimator 110 includes an I / O unit 112, a communication unit 113, a memory 114, and a CPU (Central Processing Unit) 115. The I / O unit 112 acquires the measurement value 303 from the

sensors

301 and 302. The communication unit 113 transmits and receives the angular velocity command value ω _t2 and the estimated torque T _t2 to and from the power estimator 120. The memory 114 stores data temporarily used by the CPU 115. The CPU 115 performs operations such as multiple regression analysis and system identification based on the measured value 303 to construct the torque estimation model 111. The I / O unit 112 corresponds to the “state quantity acquisition unit” in the present invention.

The power estimator 120 includes

communication units

121 and 122, a memory 123, and a CPU 124. The communication unit 121 transmits and receives the angular velocity command value ω _t2 and the estimated torque T _t2 to and from the model estimator 110. Communication unit 122 transmits estimated power P _t2 to inverter 130. The memory 123 stores data temporarily used by the CPU 124. The CPU 124 estimates the estimated power P _t2 based on the estimated torque T _t2 .

The inverter 130 includes a communication unit 132, an I / O unit 133, a memory 134, and a CPU 135 in addition to a circuit unit such as a switching element (not shown). The communication unit 132 receives the estimated power P _t2 from the power estimator 120. The I / O unit 133 outputs an inverter output 136 to the electric motor 201. The memory 134 stores data temporarily used by the CPU 135. CPU135 controls operation | movement of the switching element with which the inverter 130 is provided, and implements power conversion. Further, the power is stored in the capacitor 131 according to the value of the estimated power _Pt2 .

<Embodiment 1: Summary>
As described above, the power control apparatus 100 according to the first embodiment is necessary for constructing the torque estimation model 111 that estimates the model generated in the electric motor 201 in time series and driving the electric motor 201 using the model. The power value P _t2 is estimated in time series. Thereby, since the electric power which the electric motor 201 requires can be estimated and prepared in advance, the possibility that the electric power supplied to the electric motor 201 is insufficient and causes malfunction or the like can be reduced.

The power control apparatus 100 according to the first embodiment obtains the estimated torque T _t2 of the electric motor 201 at the future time t2 by inputting the angular velocity command value ω _t2 at the future time _t2 to the torque estimation model 111. Moreover, the electric power P _t2 required by the electric motor 201 at the future time t2 is estimated using the estimated torque T _t2 . Thereby, before the specific time arrives, the electric power required at that time can be prepared, which is advantageous in that the mechanical system 200 can be systematically operated in addition to the above advantages. It is.

<Embodiment 2>
In the first embodiment, the power estimator 120 compares the estimated torque T _t2 or the estimated power P _t2 with these reference values at a predetermined time t2, and when both are extremely different from each other, It may be determined that an abnormality has occurred in the electric motor 201 or the mechanism unit 202. Similarly, the estimated torque T _t2 or the estimated power P _t2 may be compared with these measured values (obtained from the sensors 301 and 302) to determine abnormality. The reference value and the threshold value for determining an abnormality may be stored in advance in a storage device such as an HDD (Hard Disk Drive) or a flash memory.

When the power estimator 120 determines that an abnormality has occurred in the electric motor 201 or the mechanism unit 202, the electric power estimator 120 calculates a power value that stops them or restores them to a normal state, and notifies the inverter 130 of them. The inverter 130 can drive or control the electric motor 201 based on the electric power value, thereby stopping the electric motor 201 or the mechanism unit 202 or returning it to a normal state.

<Embodiment 3>
FIG. 3 is a functional block diagram of the power control apparatus 100 according to the third embodiment of the present invention. The power control apparatus 100 according to the third embodiment has the same configuration as that of the first and second embodiments, except that each functional unit is built in the inverter 130 and integrally configured.

The inverter 130 according to the third embodiment includes all the internal configurations of the model estimator 110, the power estimator 120, and the inverter 130 described in FIG. However, it is not always necessary to provide the same number of components as those shown in FIG. Further, the

communication units

113, 121 to 122, 132 are not necessary.

In the third embodiment, compared to the case where the model estimator 110 and the power estimator 120 are installed outside the inverter 130, the communication load for transmitting and receiving estimated values and the like can be reduced. Moreover, the number of parts as the whole power control apparatus 100 can be reduced by sharing parts.

<Embodiment 4>
FIG. 4 is a functional block diagram of the power control apparatus 100 according to the fourth embodiment of the present invention. In the fourth embodiment, there are two systems of the inverter 130, the electric motor 201, and the power source 400, respectively. For convenience, each system is distinguished using the subscripts a and b. Further, description of some components such as the sensor 301 is omitted.

In the fourth embodiment, the model estimator 110 constructs torque estimation models 111a and 111b for the

electric motors

201a and 201b, respectively.

The power estimator 120 inputs the angular velocity command value ω _t2 at the future time t2 to the torque estimation model 111, thereby obtaining the estimated torques T _t2 and T ′ _t2 of the

electric motors

201a and 201b at the future time t2. Electric power estimator 120 estimates electric powers P _t2 and P ′ _t2 required by

electric motors

201a and 201b at future time t2 based on each estimated torque, and notifies

inverters

130a and 130b, respectively.

Inverters

130a and 130b supply electric power to

electric motors

201a and 201b, respectively, and drive mechanism 202. Further, electric power is stored in the capacitors 131a and 131b based on the estimated electric powers P _t2 and P ′ _t2 .

Other configurations are the same as those in the first to third embodiments, and thus description thereof is omitted.

In the fourth embodiment, the operations of the

electric motors

201a and 201b may be the same or different. When both operations are the same, the measured values of the sensors are the same, so the torque estimation models 111a and 111b, the estimated torques T _t2 and T ′ _t2 , and the estimated powers P _t2 and P ′ _t2 should be the same. It is. Therefore, the power estimator 120 may determine that an abnormality has occurred in at least one of the electric motor 201 and the mechanism unit 202 when any one of them does not match.

When the power estimator 120 determines that an abnormality has occurred in the electric motor 201 or the mechanism unit 202, the power estimator 120 obtains power values P _t2 and P ′ _t2 that stop these operations or return to normal operations. Each inverter 130 may be notified. As a result, the abnormal operation can be promptly stopped or returned to the normal operation.

Similarly, when it is determined that an abnormality occurs in the electric motor 201 or the mechanism unit 202 at a future time t2, the same processing may be executed. Thereby, the malfunction by abnormal operation | movement can be suppressed beforehand.

<Embodiment 5>
FIG. 5 is a configuration diagram of

power control systems

1000a and 1000b according to Embodiment 5 of the present invention. The

power control systems

1000a and 1000b are systems each including the power control device 100, the mechanical system 200, and the

sensors

301 and 302 described in the first to fourth embodiments. Here, it is assumed that there are two processes that are work targets of the mechanical system 200, and the two power control systems 1000 are illustrated. However, the number and connection relationship of the power control systems 1000 may be arbitrary.

Power control systems

1000a and 1000b include

communication devices

500a and 500b, respectively, and transmit and receive at least one of measured values of each sensor, torque estimation model 111, estimated torque T _t2 , and estimated power P _t2 to each other. Can do.

When the process targeted by the power control system 1000a and the process targeted by the power control system 1000b are continuous without interruption, the torque T and power of the motor 201 required at the time when one process ends. P and the like seem to be substantially the same value at the time when the next process starts. In such a case, if these values are shared among the power control systems 1000 and these values in the previous process are taken over when the next process starts, the next process can be started smoothly.

Also, if an abnormality occurs in any process, it may be dangerous to continue with other processes. In such a case, when one of the power estimators 120 detects an abnormality, it notifies the other power estimators 120 to that effect, and promptly stops other processes to ensure the safety of the work site. be able to.

<Embodiment 6>
FIG. 6 is a configuration diagram of

power control systems

1000a and 1000b according to Embodiment 6 of the present invention. In the fifth embodiment, each power control system 1000 is connected via the

communication devices

500a and 500b. However, the host controller 600 is installed at the higher level, and the host controller 600 collects and integrates information from each communication device 500. Alternatively, each power control system 1000 may be controlled.

As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

In addition, each of the above-described configurations, functions, processing units, etc. can be realized as hardware by designing all or a part thereof, for example, with an integrated circuit, or the processor executes a program for realizing each function. By doing so, it can also be realized as software. Information such as programs and tables for realizing each function can be stored in a storage device such as a memory or a hard disk, or a storage medium such as an IC card or a DVD.

100: Power controller 110: Model estimator 111: Torque estimation model 112: I / O unit 113: Communication unit 114: Memory 115: CPU 120: Power estimator 121-122: Communication unit , 123: Memory, 124: CPU, 130: Inverter, 131: Capacitor, 132: Communication unit, 133: I / O unit, 134: Memory, 135: CPU, 136: Inverter output, 200: Mechanical system, 201: Electric motor 202: mechanism unit, 301 to 302: sensor, 303: measurement value, 400: power supply, 500: communication device, 600: host controller, 1000: power control system.

Claims

An apparatus for controlling electric power supplied to a mechanical system having a mechanism that is driven using an electric motor,
A state quantity acquisition unit for acquiring a measurement value of a physical state quantity of the electric motor or the mechanism unit;
Using the measurement value acquired by the state quantity acquisition unit, a model estimation unit that constructs a torque estimation model that estimates torque generated in the electric motor in time series, and
A power estimation unit that estimates a power value necessary for driving the motor in a time series based on a time series estimation value of the torque obtained from the torque estimation model;
An inverter that drives the electric motor by supplying electric power of the electric power value estimated by the electric power estimation unit to the electric motor;
A power control apparatus comprising:
The model estimation unit includes:
Build the torque estimation model with the angular velocity command value for the motor as a variable,
The power estimation unit
By inputting an angular velocity command value at a future time for the electric motor to the torque estimation model, an estimated value of the torque at the future time is obtained,
The power control apparatus according to claim 1, wherein a power value necessary for driving the motor at the future time is estimated using the estimated value.
The power estimation unit
Notifying the inverter of the power value required to drive the electric motor at the future time,
The inverter is
The power control apparatus according to claim 2, wherein power sufficient to supply electric power corresponding to the electric power value to the electric motor at the future time is charged in advance before reaching the future time.
The power estimation unit
Monitoring the abnormal operation of the mechanical system by comparing the estimated value of the torque or the estimated value of the electric power required to drive the electric motor with a predetermined reference value or an actual measured value;
When an abnormal operation of the mechanical system is detected, the power value for stopping the operation of the mechanical system or returning to the normal operation is obtained and output to the inverter,
The inverter is
The power control apparatus according to claim 1, wherein power supplied to the mechanical system is controlled based on the power value to stop or return the operation of the mechanical system to normal operation.
The model estimation unit includes:
The power control apparatus according to claim 1, wherein the torque estimation model is constructed by performing a multiple regression analysis or a system identification calculation using the measurement value acquired by the state quantity acquisition unit.
The power control apparatus according to claim 1, wherein the model estimation unit or the power estimation unit is built in the inverter.
The model estimation unit includes:
If the mechanical system comprises a plurality of the motors, build the torque estimation model for each motor,
The power estimation unit
The power control apparatus according to claim 1, wherein a power value necessary for driving each motor is estimated in time series using the torque estimation model for each motor.
The power estimation unit
Compare the power value required to drive each electric motor, and if there is a difference, determine that an abnormality has occurred in the mechanical system, and stop the operation of the mechanical system or change it to normal operation. Find the power value to be restored and output to the inverter,
The inverter is
The power control apparatus according to claim 7, wherein the power supplied to the mechanical system is controlled based on the power value, and the operation of the mechanical system is stopped or returned to a normal operation.
A power control device according to claim 1;
A sensor for measuring a physical state quantity of the electric motor or the mechanism unit and outputting the measured value to the power control device;
A power control system comprising:
The sensor is
An angle sensor or an angular velocity sensor that measures an angular velocity of the electric motor, a current sensor that measures a motor torque of the electric motor, a displacement sensor that measures a displacement of the mechanism portion, or a strain sensor that measures a load of the mechanism portion. The power control system according to claim 9, wherein the power control system is installed inside the system or on the surface of the housing.
A plurality of power control devices according to claim 1,
Each of the power control devices
Controlling the power supplied to the different mechanical systems,
At least one of the torque estimation model, the estimated value of the torque, and an electric power value necessary for driving the electric motor is mutually transmitted and received and shared.
The different mechanical systems are configured to carry out a continuous work process;
The power control device
The power supplied to the mechanical system in the previous process is controlled so that at least one of the torque estimation model, the estimated value of the torque, and the power value required to drive the electric motor is continuous from the previous process. The power control system according to claim 11, wherein the power control system takes over the value from the other power control device.