JP2020120573A - Design support device, design support method, and design support program - Google Patents

Abstract

To analyze stability of a DC power supply system in which power is supplied from a DC power supply through a DC bus to a plurality of servo devices including an inverter circuit and an electric motor, and reflect the analysis to the details of control.SOLUTION: A design support device, based on system information on a DC power supply system and operation pattern information indicating respective operation patterns of a plurality of servo devices included therein, creates time-series current data indicating a time variation pattern of the total value of current supplied to the plurality of servo devices through a DC bus, based on an output impedance Z(s) of a power supply-side part of the DC power supply system, and an input impedance Z(s) of a load-side part of the DC power supply system, the input impedance Z(s) also being a function of the value of current flowing in the DC bus, outputs information indicating stability of the DC power supply system when the current flowing in the DC bus becomes the maximum value of the created time-series current data, and changes the operation pattern information based on the information.SELECTED DRAWING: Figure 1

Description

The present invention relates to a design support device, a design support method, and a design support program.

In factories and the like, a system in which a plurality of electric motors are PWM-driven by a plurality of servo drivers arranged at distant places (a system including a robot and its controller) is used. In such a system, switching speed cannot be increased in order to reduce radiation noise from a long cable between the motor and the servo driver, and a large number of cables are required for connection between the motor and the servo driver. There is.

If only the inverter circuit in the servo driver is arranged near each motor and the power is supplied from a single DC power source to a plurality of inverter circuits via the DC bus, the above problem will not occur. You can However, in a system adopting this configuration, it is known that the LC circuit on the DC bus side and the inverter circuit side may interfere with each other to make the operation of the system unstable (for example, Non-Patent Document 1). reference). Therefore, when adopting the above configuration, it is desired to analyze the stability in consideration of the control content for each inverter circuit.

Masashi Yokoo, Keiichiro Kondo, “Damping control system design method for vector-controlled induction motor drive system in DC electric railway vehicles”, IEEJ Transactions, Vol. 135 No.6 pp.622-631 (2015) R. D. Middlebrook, "Input Filter Considerations in Design and Application of Switching Regulators", Proc, IEEE Industrial Application Society Annual Meeting pp.363-382 (1976).

The present invention has been made in view of the above-mentioned current situation, and improves the stability of a DC power supply system in which power is supplied from a DC power supply to a plurality of servo devices including an inverter circuit and an electric motor by a DC bus, with respect to each servo device. The purpose is to provide a technology that analyzes (evaluates) in consideration of the control content and reflects it in the control content.

A design support device according to one aspect of the present invention is a device for supporting the design of a DC power supply system in which electric power is supplied from a DC power supply to a plurality of servo devices including an inverter circuit and an electric motor by a DC bus. Acquisition means for acquiring system information indicating a configuration of the DC bus and the plurality of servo devices of the DC power supply system, and operation pattern information indicating operation patterns of the plurality of servo devices, and the DC power supply system Is regarded as a connection system in which a load side portion including the plurality of servo devices and a power source side portion that supplies electric power to the load side portion are connected, the output impedance Z _o (s of the power source side portion ) (S is a Laplace operator) and the input impedance Z _in (s) of the load side, the bus current value being the current value flowing through the DC bus, and the q-axis of the motor at the bus current value. Output means for outputting information on the stability of the DC power supply system based on Z _in (s) which is also a function of the conversion rate α to current, the system information obtained by the obtaining means, and each servo device On the basis of the operation pattern information acquired for the plurality of servo devices, time-series current data indicating a time change pattern of the total current value supplied to the plurality of servo devices is generated, and the time series current data is flowed through the DC bus. A control unit that causes the output unit to output the information when the current value is the maximum value of the generated time-series current data, and changes the operation pattern information based on the information.

That is, a DC power supply system in which electric power is supplied from a DC power supply to a plurality of servo devices including an inverter circuit and an electric motor by a DC bus becomes unstable when a large current flows through the DC bus. As described above, the design support device, based on the operation pattern information acquired for each servo device, the time-series current indicating the time change pattern of the total current value supplied to the plurality of servo devices via the DC bus. It is configured to generate data and output information regarding the stability of the DC power feeding system when the current flowing through the DC bus has the maximum value of the generated time series current data. Therefore, according to the design support device, the stability of the DC power supply system in which electric power is supplied from the DC power supply to the plurality of servo devices including the inverter circuit and the electric motor by the DC bus is taken into consideration in the control content for each servo device. Then, analysis (evaluation) is performed, and in consideration of the analysis result, it is possible to obtain an operation pattern for actually driving the servo device in which the DC power feeding system does not become unstable.

The output means of the design support device may output information regarding the stability of the DC power feeding system in any form. Specifically, even if the output means displays the information (Nyquist diagram or Bode diagram) on the stability of the DC power feeding system on the screen of the display, the data (numerical value) representing the Nyquist diagram or the like is displayed. Group) may be output.

Further, the output means obtains the input impedance Z _in (s) of each servo device from the following equations (1) to (4) and synthesizes the obtained Z _in (s) to obtain the load side portion. The input impedance Z _in (s) may be obtained.

Note that V _b and I _b are the voltage and current of the DC bus, R _m and L _m are the resistance and inductance of the electric motor of each servo device, and K _p and K _i are the respective values. It is a proportional gain and an integral gain of PI control performed to match the q-axis current to the electric motor of the servo device with the current command.

According to another aspect of the present invention, there is provided a design support method for supporting the design of a DC power supply system in which power is supplied from a DC power supply to a plurality of servo devices including an inverter circuit and an electric motor by a DC bus. Based on the system information indicating the configurations of the DC bus and the plurality of servo devices of the system, and the operation pattern information indicating the operation patterns of the plurality of servo devices, the plurality of the plurality of servo devices are connected via the DC bus. A power supply side that generates time-series current data indicating a time change pattern of the total current supplied to the servo device and supplies the DC power supply system with a load side part including the plurality of servo devices and power to the load side part. The output impedance Z _o (s) of the power source side (s is a Laplace operator) and the input impedance Z _in (s) of the load side when the connection system is considered to be connected to the load side. The DC bus based on the bus current value which is the current value flowing through the DC bus and Z _in (s) which is also a function of the conversion rate α of the bus current value to the q-axis current of the electric motor. Information about the stability of the DC power feeding system when the flowing current value is the maximum value of the generated time series current data is output, and the operation pattern information is changed based on the information. A design support program according to one aspect of the present invention causes a computer to operate as a design support apparatus having any one of the above configurations. Therefore, even by these techniques, the stability of the DC power feeding system is analyzed (evaluated) in consideration of the control content for each servo device, and the DC power feeding system does not become unstable. It is possible to obtain the operation pattern.

According to the present invention, the stability of a DC power supply system in which electric power is supplied from a DC power supply to a plurality of servo devices including an inverter circuit and an electric motor by a DC bus is analyzed in consideration of control contents for each servo device. It is possible to (evaluate) and reflect that in the control content.

FIG. 1 is a block diagram of a design support device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a configuration example of a DC power feeding system whose stability is analyzed by the design support device. FIG. 3 is a control block diagram showing the control contents of the q-axis current of the control unit included in the servo device. FIG. 4 is an explanatory diagram of LC parallel circuit information. FIG. 5A is an explanatory diagram of a shape example of a Nyquist diagram displayed when each servo device operates stably by controlling according to the operation pattern information. FIG. 5B is an explanatory diagram of a shape example of the Nyquist diagram that is displayed when each servo device does not operate stably under the control according to the operation pattern information. FIG. 6 is a control block diagram showing the control contents of the q-axis current used by the design support device to specify Z _D (s) and T(s). FIG. 7 is an explanatory diagram of the result of an experiment conducted to confirm that the stability can be analyzed by the design support device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of a design support device 10 according to an embodiment of the present invention, and FIG. 2 shows a configuration example of a DC power feeding system whose stability is analyzed by the design support device 10.

The design support apparatus 10 (FIG. 1) according to the present embodiment is an apparatus developed to support the design of the DC power feeding system by analyzing the stability of the DC power feeding system having the configuration shown in FIG. Is.

Specifically, as shown in FIG. 2, the DC power supply system (hereinafter also referred to as an analysis target system) in which the design support apparatus 10 analyzes the stability is configured by the inverter circuit 41, the electric motor 42, and the control unit 43. This is a system in which electric power from a DC power supply 31 is supplied to a plurality of configured servo devices via a DC bus 35.

The electric motor 42 of each servo device in the analysis target system is a permanent magnet synchronous electric motor. The control unit 43 of the servo device, the information (Figure from a sensor (not shown) for detecting the driving current of the electric motor 42 encoder attached to (not shown) and an electric motor 42, theta, i _u, i _v ), the vector control with decoupling compensation is performed with the d-axis current I _d =0.

More specifically, the control unit 43 is a unit that controls the q-axis current, as shown in FIG. Note that FIG. 3 is a control block diagram showing the control contents of the q-axis current of the control unit 43. Further, in FIG. 3, Kt is a torque constant of the electric motor 42, and K _e is an induced voltage constant of the electric motor 42. J, Dr, and K are the inertia, viscosity, and spring constant of the mechanical system (the electric motor 42 and the machine driven by the electric motor 42), respectively. _{Iq_ref} is a reference current (current command), and _Iq is a _dq- converted current of the electric motor 42 (q-axis current). The current compensator 45 is a PI compensator for matching Iq with _{Iq_ref} .

Returning to FIG. 1, the configuration and function of the design support device 10 will be described.
As illustrated, the design support device 10 includes an input device 11 such as a keyboard and a mouse, a display 12, and a main body 13.

The main body 13 includes a CPU (Central Processing Unit) and a RAM (Random Access Memory).
), a non-volatile storage device 16 (hard disk drive, solid state drive, etc.) and the like. A design support program 18 is installed in the non-volatile storage device 16 of the main body unit 13, and the main body unit 13 reads the design support program 18 into the RAM and executes the program so that the main body unit 13 includes the UI processing unit 14 and the UI processing unit 14. It operates as the stability analysis processing unit 15.

The UI processing unit 14 is a unit that acquires system information and operation pattern information for each servo device from the user through an operation on the input device 11 while displaying various image information on the screen of the display 12.

The system information acquired by the UI processing unit 14 from the user is information indicating the configuration of the analysis target system. The UI processing unit 14 acquires the following information from the user as the system information.
-LC parallel circuit designation information for handling the power supply side section 30 of the analysis target system as an LC parallel circuit having the configuration shown in FIG. 4-Output voltage V _b (DC converter 31 for converting system voltage to DC) (output voltage V _b ( Hereinafter, also referred to as DC bus voltage V _b )
Inductance _{L m} of the electric motor 42 of each servo device, armature resistance _{R m}
・Proportional gain K _p and integral gain K _i of the current compensator 45 (FIG. 3) of each servo device

LC parallel circuit designation information UI processing unit 14 obtains from the user, the C _b in FIG. 4, but including capacitance and DC bus capacitance of the input capacitor of the inverter circuit 41.

In addition, the UI processing unit 14 acquires display target designation information from the user. The display target designation information is information that designates one or more DC bus currents I _b that cause the stability analysis processing unit 15 to display the Nyquist diagram. The display target designation information may be information that directly designates one or more DC bus currents I _b or information that indirectly designates one or more DC bus currents I _b .

The operation pattern information for each servo device acquired by the UI processing unit 14 from the user is a command value group (time-series data of position command, etc.) input to each control unit 43 in order to operate each servo device.

The UI processing unit 14 normally waits for the user to input the system information and the operation pattern information of each (all) servo device. Then, the UI processing unit 14 instructs the stability analysis processing unit 15 to start the stability analysis process when the user inputs an instruction to execute the stability analysis process after the input of the information is completed.

The stability analysis process executed by the stability analysis processing unit 15 includes a total current calculation process and a Nyquist diagram display process.
The total current calculation process is based on the information (inductance L _m proportional gain K _p etc.) about each servo device in the system information and the operation pattern information of each servo device, and the current supplied from the DC power supply 31 to each servo device. Of the current time series data is generated, current values at the same time in the generated time series data are added, and the maximum value of the current flowing through the DC bus 35 (hereinafter referred to as the maximum current value) is calculated from the addition result. Is.

The Nyquist diagram display process is basically based on the system information and the output impedance Z _o (s) (s is a Laplace operator) of the power supply side unit 30 of the analysis target system (FIG. 2) and the analysis target system. The input impedance Z _in (s) of the load side portion 40 is specified, and the specified Z _o (
s) and Z _in (s) to “Z _o (s)/Z _in (s)” Nyquist diagram 12
This is a process to be displayed on the screen of. However, the Nyquist diagram display processing is processing that uses a function of s and a specified current value (D value described later) that correlates with the DC bus current I _b as the input impedance Z _in (s) of the load side unit 40. , DC bus current I _b is a process of displaying a Nyquist diagram when the maximum current value is calculated by the total current calculation process.

Therefore, when the stability analysis processing is performed, for example, the Nyquist diagram shown in FIGS. 5A and 5B is displayed on the screen of the display 12. The Nyquist diagram shown in FIG. 5A is an explanatory diagram of a shape example of the Nyquist diagram displayed when each servo device operates stably by control according to the operation pattern information, and is shown in FIG. 5B. The Nyquist diagram is an explanatory diagram of a shape example of the Nyquist diagram displayed when each servo device does not operate stably under the control according to the operation pattern information.

Hereinafter, the Nyquist diagram display process will be described more specifically.

During the Nyquist diagram display process, the stability analysis processing unit 15 calculates the output impedance Z _o (s) of the power supply side unit 30 of the system to be analyzed based on the system information (LC parallel circuit information), using the following formula (A1). Prepare the function represented by.

また、安定性解析処理部１５は、負荷側部４０の入力インピーダンスＺ_ｉｎ(ｓ)（以下、Ｚ_{ｉｎａｌｌ}(ｓ)とも表記する）を求めるために、各サーボ装置に関するシステム情報（ＬＣ並列回路情報以外の情報）に基づき、各サーボ装置の入力インピーダンスＺ_ｉｎ(
ｓ)として、以下の（Ａ２）式を満たす関数を用意する。

Further, the stability analysis processing unit 15 _obtains the input impedance Z _in (s) (hereinafter also referred to as Z _inall (s)) of the load side unit 40 _in order to obtain system information (LC parallel circuit information) regarding each servo device. Input information Z _in (
As s), a function satisfying the following expression (A2) is prepared.

この（Ａ２）式において、Ｚ_Ｎ(ｓ)は、理想フィードバック時におけるサーボ装置の入力インピーダンスである。また、Ｚ_Ｄ(ｓ)は、無帰還時（フィードバックがない場合）におけるサーボ装置の入力インピーダンスであり、Ｔ(ｓ)は、サーボ装置の一巡伝達関数である。

In this equation (A2), Z _N (s) is the input impedance of the servo device during ideal feedback. Further, Z _D (s) is the input impedance of the servo device when there is no feedback (when there is no feedback), and T(s) is the loop transfer function of the servo device.

Then, the stability analysis processing unit 15 uses the Z _in (
s) is synthesized to prepare the input impedance Z _inall (s) of the load side portion 40 (entire plural servo devices). That is, the stability analysis processing unit 15 determines Z _in (s) of each servo device as Z _i (s) (i=, assuming that each servo device is uniaxially connected to the DC bus 35). 1 to imax), Z _inall (s) satisfying the following formula is prepared.

More specifically, the input impedance of the servo device at the ideal feedback is -V _{b /} I b. That is, Z _N (s) can be represented by the following formula (B0).

Further, what is fed back in the servo device is I _q (see FIG. 4). Therefore, the input impedance and open loop transfer function of the servo device when I _q is not fed back are used as Z _D (s) and T(s), respectively.

The input impedance and open loop transfer function of the servo device when I _q is not fed back can be obtained from FIG. However, if the functions obtained from FIG. 3 are used as Z _D (s) and T(s), the calculation load at the time of displaying the Nyquist diagram becomes large.

Here, considering that the response of the mechanical system of the servo device (usually several hundred Hz) is considerably lower than the resonance frequency of the power supply side unit 30, a control block diagram in which H(s) is ignored, that is, From the control block diagram shown in FIG. 6, stability is obtained even if the input impedance and open loop transfer function of the servo device when I _q is not fed back are obtained and used as Z _D (s) and T(s). It can be evaluated well.

Since PI(s) and G(s) can be represented by the following equations (A3) and (A4), respectively, T(s) can be represented by the equation (A5).

Further, the input impedance Z _D (s) of the servo device when I _q is not fed back becomes an electric time constant part of the electric motor 42. However, the input impedance Z _D (s) obtained from FIG. 6 is a value on the side of V _q and I _q . Therefore, stability analysis processing section 15, the following (A6) equation holds for conversion alpha (described later in detail) with the input impedance Z _D (s) obtained from FIG. 6, V _q, I _q By converting to the value on the side, Z _D (s) represented by the following formula (A7) is prepared. In addition, when preparing the Z _D (s), the stability analysis processing unit 15 according to the present embodiment, when the operation pattern information of each servo device is set, displays the machine information such as inertia related to the servo device. The change pattern of the speed and the current command value is specified based on the set operation pattern information, and the conversion rate α is calculated from the specified result. Further, when the operation pattern information of each servo device is not set, the stability analysis processing unit 15 calculates the conversion rate α by the above procedure based on the operation pattern information prepared in advance.

As described above, the stability analysis processing unit 15 that has prepared Z _o (s), Z _N , Z _D (s), and T(s) has Z _N , Z _D (s), and T(s) ( The input impedance Z _in (s) of the load side portion 40 (one servo device) is prepared from the equation A2). The stability analysis processing unit 15 then, based on the prepared Z _in (s) and Z _o (s), for each DC bus current I _b (directly or indirectly) designated by the display target designation information. , DC bus current I _{b for} each D value), a Nyquist diagram of “Z _o (s)/Z _in (s)” is displayed on the screen of the display 12.

Hereinafter, some items will be supplemented.
The Nyquist plots shown in FIGS. 5A and 5B are obtained by performing the Nyquist plot display processing under the conditions that the maximum current values are Imax1 and Imax2 (Imax1<Imax2), respectively.

As the K _p value and the K _i value in the equation (A5), values determined so that the frequency across 0 dB in the Bode diagram of T(s) becomes a predetermined frequency were adopted.

FIG. 7 shows the experimental results of actually controlling the DC power feeding system under the same conditions as the conditions under which the Nyquist diagram display processing was performed.

As is apparent from FIG. 7, as the speed increases, the DC bus current I _b increases and increases until the DC bus current I _b approaches Imax2, which is determined from the Nyquist diagram shown in FIG. 5B. It was confirmed that the DC bus current I _b and the DC bus voltage V _b started to oscillate as the stability.

In this way, the design support device 10 (stability analysis processing unit 15) can display the Nyquist diagram (FIGS. 5A and 5B) corresponding to the actual operation of the DC power feeding system. Therefore, according to the design support device 10, it is possible to analyze (determine) the stability of the DC power feeding system in consideration of the control content for the servo device (the inverter circuit 41).

Further, along with the display of the Nyquist diagram on the screen of the display 12 described above, the design support device 10 causes each servo initially input by the user to be based on the analysis (judgment) result of the stability of the DC power feeding system. The operation pattern information of the device, that is, the operation pattern information used for the stability analysis is changed to operation pattern information that can stably operate the DC power feeding system. Such a function is, for example, to obtain a DC bus current Ib that can obtain a Nyquist diagram indicating that the DC bus current Ib is obtained and a ratio (Ib/Ib/) of the maximum current value calculated in the total current calculation process. This can be realized by changing the initial operation pattern information of each servo device so that the acceleration of the electric motor 42 decreases at a rate according to the (maximum current value). As a result, it is possible to obtain an operation pattern for actually driving the servo device in which the DC power supply system does not become unstable. This ends the stability analysis process.

Finally, the reason why the above expression (A6) is established will be explained.
The following formula (B1) is established among the DC bus voltage V _b , the DC bus current I _b , the d-axis voltage V _d , the d-axis current I _d , the q-axis voltage V _q, and the q-axis current I _q. .. And since I _d =0,
The expression (B1) can be transformed into the following expression (B2).

From the equation (B2), the following equation (B3) is established for the conversion rate α which is the ratio of the DC bus current I _b and the q-axis current I _q . Therefore, the following expression (B4), that is, the above expression (A6) is established.

<<Deformation>>
The design support device 10 described above can be modified in various ways. For example, if the stability analysis process is transformed into a process for displaying the Bode diagram of Z _o (s) and Z _in (s) instead of the Nyquist diagram of Z _o (s)/Z _in (s), good. In addition, when the Bode diagram is used, it can be determined that it becomes stable when the magnitude of Z _o (s)/Z _in (s) is 1 or less or the phase difference is 180 degrees or less. Further, the stability analysis process may be modified into a process of outputting data (numerical value group) representing the Nyquist diagram or the Bode diagram, instead of the process of displaying the Nyquist diagram or the Bode diagram. When the stability analysis process is transformed into such a process, the stability analysis process may be provided with a function of determining whether it is stable and outputting the determination result. Further, some functions may be removed from the design support device 10, and the design support device 10 may be a device that inputs and outputs information via a network (in other words, an input device 11 and a display 12 are provided. It is a matter of course that it may be transformed into a non-apparatus).

<<Appendix 1>>
A design support device for supporting the design of a DC power supply system in which electric power is supplied from a DC power supply (31) to a plurality of servo devices including an inverter circuit (41) and an electric motor (42) via a DC bus (35) ( In 10),
An acquisition unit (14) that acquires system information indicating the configurations of the DC bus (35) and the plurality of servo devices of the DC power supply system, and operation pattern information indicating the respective operation patterns of the plurality of servo devices. )When,
The DC power supply system was regarded as a connection system in which a load side part (40) including the plurality of servo devices and a power supply side part (30) supplying power to the load side part (40) were connected. The output impedance Z _o (s) (s is the Laplace operator) of the power supply side (30) and the input impedance Z _in (s) of the load side (40) in the case flowing through the DC bus. Outputs information on the stability of the DC power supply system based on a bus current value that is a current value and Z _in (s) that is also a function of the conversion rate α of the bus current value to the q-axis current of the electric motor. Output means (15) for
The time change pattern of the total current supplied to the plurality of servo devices via the DC bus is shown based on the system information acquired by the acquisition means and the operation pattern information acquired for each servo device. When the time series current data is generated and the current flowing through the DC bus becomes the maximum value of the generated time series current data, the information is output to the output means, and the operation pattern information is calculated based on the information. Control means (15) for changing,
A design support device (10) provided with.

10 Design Support Device 11 Input Device 12 Display 13 Main Body 14 UI Processing Unit 15 Stability Analysis Processing Unit 16 Nonvolatile Storage Unit 18 Design Support Program 30 Power Supply Side 31 DC Power Supply 40 Load Side 41 Inverter 42 Electric Motor 43 Control Section

Claims (6)

In a design support device for supporting the design of a DC power supply system in which electric power is supplied from a DC power supply to a plurality of servo devices including an inverter circuit and an electric motor by a DC bus,
An acquisition unit that acquires system information indicating a configuration of the DC bus and the plurality of servo devices of the DC power feeding system, and operation pattern information indicating an operation pattern of each of the plurality of servo devices.
Output impedance of the power supply side part when the DC power supply system is regarded as a connection system in which a load side part including the plurality of servo devices and a power supply side part that supplies power to the load side part are connected Z _o (s) (s is a Laplace operator) and the input impedance Z _in (s) of the load side, the bus current value being the current value flowing through the DC bus and the bus current value, Output means for outputting information on the stability of the DC power supply system based on Z _in (s) which is also a function of the conversion rate α of the motor to the q-axis current and
Based on the system information acquired by the acquisition unit and the operation pattern information acquired for each servo device, a time change pattern of the total current value supplied to the plurality of servo devices via the DC bus is calculated. The time series current data shown is generated, and the information when the current value flowing through the DC bus becomes the maximum value of the generated time series current data is output to the output means, and the operation pattern is based on the information. Control means for changing information,
Design support device. The output means outputs a Nyquist diagram of "Z _o (s)/Z _in (s)".
The design support apparatus according to claim 1, wherein: The output means outputs Bode diagrams of Z _o (s) and Z _in (s),
The design support apparatus according to claim 1, wherein: The output means obtains the input impedance Z _in (s) of each servo device from the following equations (1) to (4), and synthesizes the obtained Z _in (s) to input the load side input. Find the impedance Z _in (s),
The design support apparatus according to any one of claims 1 to 3, wherein:

Note that V _b and I _b are the voltage and current of the DC bus, R _m and L _m are the resistance and inductance of the electric motor in each servo device, and K _p and Ki are the respective values. It is a proportional gain and an integral gain of PI control performed to match the q-axis current to the electric motor in the servo device with the current command. In a design support method for supporting the design of a DC power supply system in which electric power is supplied from a DC power supply to a plurality of servo devices including an inverter circuit and an electric motor by a DC bus,
Based on the system information indicating the configurations of the DC bus and the plurality of servo devices of the DC power feeding system, and the operation pattern information indicating the respective operation patterns of the plurality of servo devices, the information is transmitted via the DC bus. Generates time-series current data showing the time change pattern of the total current supplied to multiple servo devices,
Output impedance of the power supply side part when the DC power supply system is regarded as a connection system in which a load side part including the plurality of servo devices and a power supply side part that supplies power to the load side part are connected Z _o (s) (s is a Laplace operator) and the input impedance Z _in (s) of the load side, the bus current value being the current value flowing through the DC bus and the bus current value, Based on Z _in (s), which is also a function of the conversion rate α of the motor to the q-axis current, and the value of the current flowing through the DC bus is the maximum value of the generated time series current data, the DC Outputting information on the stability of the power supply system and changing the operation pattern information based on the information,
Design support method. A design support program that causes a computer to operate as the design support apparatus according to claim 1.

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