Design support device, design support system, and design support method

Abstract

To provide a design assistance device, a design assistance system, and a design assistance method which can shorten the time required for designing a power conversion device and suppress the increase of development costs of the power conversion device.SOLUTION: A design assistance device 100 includes a noise acquisition unit 1, a noise determination unit 2, and a drive capability determination unit 3. The noise acquisition unit 1 acquires a detection result of converter noise being noise generated from a power conversion device 200, as actually measured noise. The noise determination unit 2 determines whether the converter noise is within a predetermined target range or not based on the actually measured noise acquired by the noise acquisition unit 1. If the converter noise is not within the target range, the drive capability determination unit 3 determines a target drive capability being a target of adjustment of drive capability of a drive circuit 250.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a design assistance device, a design assistance system, and a design assistance method. [Background technology]

[0002] Power conversion devices including semiconductor switching elements are used in many devices. However, noise generated by the power conversion device can cause malfunctions in devices around the power conversion device or in the power conversion device itself. To prevent such malfunctions due to noise, the noise generated by the power conversion device must comply with a predetermined standard. One method for adjusting the noise generated by the power conversion device is, for example, to adjust the amount of noise generated by the power conversion device by adjusting the switching speed of the semiconductor switching elements.

[0003] For example, in the design support device described in Patent Document 1, after determining the amount of electromagnetic radiation noise, the switching voltage corresponding to the gate resistance of the drive circuit is calculated by circuit analysis, and the amount of electromagnetic radiation noise at that time is estimated.The estimated amount of noise is compared with a target value, and the gate resistance value is corrected based on the result, and the estimation is repeated, thereby designing a gate drive circuit such that the amount of noise reaches the target value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2011 / 152225 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if all parameters related to a power conversion device are calculated through analysis and the power conversion device is designed and manufactured based on the analysis results, there is a possibility that the noise calculated through analysis will differ from the noise actually measured. If a discrepancy occurs, measures such as resetting the conditions of the designed gate circuit or adding additional components will be necessary. As a result, the time required to design the power conversion device will increase and development costs will increase.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a design assistance device, a design assistance system, and a design assistance method that can shorten the time required to design a power conversion device and suppress increases in the development costs of the power conversion device. [Means for solving the problem]

[0007] The design assistance device according to the present disclosure is a design assistance device that assists in the design of a power conversion device having a semiconductor switching element and a drive circuit that drives the semiconductor switching element, and includes a noise acquisition unit that acquires the detection result of converter noise, which is noise generated from the power conversion device, as measured noise, a noise determination unit that determines whether the converter noise is within a predetermined target range based on the measured noise acquired by the noise acquisition unit, and a drive capacity determination unit that determines a target drive capacity as a target for adjusting the drive capacity of the drive circuit if the converter noise is not within the target range. [Effects of the Invention]

[0008] According to the design assistance device, design assistance system, and design assistance method disclosed herein, it is possible to shorten the time required to design a power conversion device and to suppress increases in the development costs of the power conversion device. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a configuration of a design support system according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing a specific example of a power conversion device. [Figure 3] 1 is a flowchart of a design support process performed by the design support system according to the first embodiment. [Figure 4] FIG. 10 is a block diagram showing the configuration of a design assistance system according to a second embodiment. [Figure 5] 10 is a flowchart of a design assistance process performed by the design assistance system according to the second embodiment. [Figure 6] 10 is a flowchart of a design assistance process performed by the design assistance system according to the second embodiment. [Figure 7] FIG. 10 is a block diagram showing the configuration of a design assistance system according to a third embodiment. [Figure 8] 11 is a flowchart of a design assistance process performed by the design assistance system according to the third embodiment. [Figure 9] 11 is a flowchart of a design assistance process performed by the design assistance system according to the third embodiment. [Figure 10] 11 is a flowchart of a design assistance process performed by the design assistance system according to the third embodiment. [Figure 11] FIG. 10 is a block diagram showing the configuration of a design assistance system according to a fourth embodiment. [Figure 12] FIG. 10 is a diagram showing an example in which at least a part of the functions of the design assistance device is realized by software. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A design assistance device, a design assistance system, and a design assistance method according to embodiments of the present disclosure will be described below with reference to the drawings.

[0011] Embodiment 1 1 is a block diagram showing the configuration of a design assistance system according to Embodiment 1. As shown in FIG. 1, a design assistance system 1000 according to this embodiment includes a noise detection unit 11, a driving capability adjustment unit 12, and a design assistance device 100.

[0012] 1 assists in the design of a power conversion device 200. The power conversion device 200 includes a semiconductor switching element 240 and a drive circuit 250 that drives the semiconductor switching element 240. The power conversion device 200 will be described in detail later.

[0013] The noise detection unit 11 detects noise generated from the power conversion device 200 (hereinafter referred to as converter noise). The converter noise includes radiation noise emitted from the power conversion device 200 and conduction noise conducted from the power conversion device 200 via a conductor. The noise detection unit 11 detects the converter noise at a predetermined noise observation point outside the power conversion device 200. The noise detection unit 11 may be provided as a radiation noise detection unit (e.g., an antenna) that detects radiation noise and a conduction noise detection unit (e.g., a pseudo power circuit network) that detects conduction noise, which are separate units. The noise detection unit 11 provides the detected converter noise to the design assistance device 100.

[0014] The design assistance device 100 includes a noise acquisition unit 1, a noise judgment unit 2, and a drive capability determination unit 3. The noise acquisition unit 1 acquires converter noise (hereinafter referred to as measured noise) detected by a noise detection unit 11. The noise judgment unit 2 judges, based on the measured noise acquired by the noise acquisition unit 1, whether the converter noise is within a predetermined target range.

[0015] In this example, the noise determination unit 2 determines whether the measured noise acquired by the noise acquisition unit 1 is within a target range. Specifically, the noise determination unit 2 performs an approximation determination between the measured noise and a predetermined target noise. If the measured noise is within the approximation range of the target noise, the noise determination unit 2 determines that the measured noise is approximating the target noise, and if the measured noise is not within the approximation range of the target noise, the noise determination unit 2 determines that the measured noise is not approximating the target noise. In this case, the approximation range of the target noise corresponds to the target range. The target noise may be a value determined by a noise standard or may be a target value set by the user.

[0016] Instead of determining whether the measured noise is close to the target noise, it may be determined whether the measured noise is equal to or less than a predetermined target value. In this case, the range equal to or less than the target value corresponds to the target range.

[0017] Based on the result of the determination by the noise determination unit 2, the drive capacity determination unit 3 determines a target drive capacity, which is a target for adjusting the drive capacity of the drive circuit 250. Specifically, the drive capacity determination unit 3 determines the target drive capacity when the actually measured noise is not within the target range. The drive capacity determination unit 3 provides the determined target drive capacity to the drive capacity adjustment unit 12. The drive capacity of the drive circuit 250 corresponds to the switching speed of the semiconductor switching element. The higher the drive capacity of the drive circuit 250, the higher the switching speed of the semiconductor switching element.

[0018] The drive capacity adjustment unit 12 adjusts the drive capacity of the drive circuit 250 based on the target drive capacity from the drive capacity determination unit 3. The drive capacity adjustment unit 12 is, for example, an electric circuit that outputs an electric signal having a meaningful voltage or current value to the drive circuit, or an electric circuit that outputs a digital communication signal to the drive circuit. The drive capacity adjustment unit 12 is not limited to an electric circuit, and may also be an integrated circuit. The drive capacity adjustment unit 12 provides, for example, a drive capacity adjustment signal indicating the amount of adjustment of the drive capacity to the drive circuit 250 via wired or wireless communication.

[0019] The design assistance device 100 may be realized by a combination of hardware, such as a CPU (Central Processing Unit) and memory, and software. For example, the design assistance device 100 may be realized by a personal computer. An example of the configuration of the design assistance device 100 made up of hardware and software will be described later.

[0020] Fig. 2 is a diagram showing a specific example of a power conversion device 200. The power conversion device 200 in Fig. 2 converts DC power from a power source 201 into AC power and supplies the converted AC power to a load 203. The power conversion device 200 includes a power conversion circuit 210 that performs power conversion, and a control device 220 that controls the power conversion circuit 210.

[0021] The power conversion circuit 210 is a so-called inverter, and includes semiconductor switching elements 51, 52, 53, 54, 55, and 56, and drive circuits 61, 62, 63, 64, 65, and 66. Each of the semiconductor switching elements 51 to 56 corresponds to the semiconductor switching element 240 in Fig. 1. Each of the drive circuits 61 to 66 corresponds to the drive circuit 250 in Fig. 1.

[0022] Each of the semiconductor switching elements 51 to 56 has a positive electrode, a negative electrode, and a control electrode. The positive electrodes of the semiconductor switching elements 51, 53, and 55 are each connected to the positive electrode of the power source 201. The negative electrodes of the semiconductor switching elements 52, 54, and 56 are each connected to the negative electrode of the power source 201. The negative electrodes of the semiconductor switching elements 51, 53, and 55 are each connected to the positive electrodes of the semiconductor switching elements 52, 54, and 56. A load 203 is connected to the connection point of the semiconductor switching elements 51 and 52, the connection point of the semiconductor switching elements 53 and 54, and the connection point of the semiconductor switching elements 55 and 56.

[0023] Each of the drive circuits 61 to 66 is a so-called gate circuit. The drive circuits 61 to 66 are provided to correspond to the semiconductor switching elements 51 to 56, respectively, and are connected to the control electrodes of the semiconductor switching elements 51 to 56, respectively. Each of the drive circuits 61 to 66 is controlled by the control device 220, and provides a drive signal to the control electrode of the corresponding semiconductor switching element. Each of the semiconductor switching elements 51 to 56 performs switching when provided with a drive signal from the corresponding drive circuit.

[0024] Switching includes turn-on switching and turn-off switching. Turn-on switching is a switching operation when the semiconductor switching element 240 switches from off to on. Turn-on switching causes the semiconductor switching element 240 to transition to a mode in which the positive and negative electrodes are conductive. During turn-on switching, the voltage applied between the positive and negative electrodes decreases, and the current flowing between the positive and negative electrodes increases. Turn-off switching is a switching operation when the semiconductor switching element 240 switches from on to off. Turn-off switching causes the semiconductor switching element 240 to transition to a mode in which the positive and negative electrodes are non-conductive. During turn-off switching, the voltage applied between the positive and negative electrodes increases, and the current flowing between the positive and negative electrodes decreases. A waveform that shows the change in at least one of the voltage and current during these switching events is called a switching waveform.

[0025] Generally, when the switching waveform shows a steep change, the loss that occurs during switching decreases, but the frequency spectrum included in the switching waveform increases. As a result, converter noise increases. On the other hand, when the switching waveform shows a gradual change, the loss that occurs during switching increases, but the frequency spectrum included in the switching waveform decreases. As a result, converter noise decreases.

[0026] The drive circuit 250 is configured to have an adjustable drive capability. For example, the drive capability of the drive circuit 250 can be changed by changing a gate resistance included in the drive circuit 250, by changing a gate voltage input to the drive circuit 250, or by changing a current flowing from the drive circuit 250 to the semiconductor switching element 240. The switching waveform changes in accordance with a change in the drive capability of the drive circuit 250.

[0027] FIG. 3 is a flowchart of the design support process performed by the design support system 1000 according to the first embodiment.

[0028] First, in step S1, the noise acquisition unit 1 acquires the converter noise detected by the noise detection unit 11 as the actually measured noise.

[0029] Next, in step S2, the noise determination unit 2 determines whether the measured noise acquired by the noise acquisition unit 1 is similar to the target noise. If the measured noise is within the approximation range of the target noise, the noise determination unit 2 determines that the measured noise is similar to the target noise, and if the measured noise is not within the approximation range of the target noise, the noise determination unit 2 determines that the measured noise is not similar to the target noise. Note that the determination in step S2 may be performed only within a specific frequency range.

[0030] If the measured noise is not close to the target noise, the drive capability determination unit 3 proceeds to step S3. In step S3, the drive capability determination unit 3 determines the target drive capability so that the measured noise approaches the target noise. Specifically, if the measured noise is higher than the target noise in step S2, the drive capability determination unit 3 determines the target drive capability so that it is lower than the current drive capability, and if the measured noise is lower than the target noise in step S2, the drive capability determination unit 3 determines the target drive capability so that it is higher than the current drive capability. The amount of change in drive capability is determined based on, for example, the magnitude of the difference between the measured noise and the target noise.

[0031] In this example, when the measured noise is lower than the approximate range of the target noise, the driving capability of the driving circuit 250 is adjusted to be higher than the current level. However, the present invention is not limited to this. From the viewpoint of noise suppression, it is not a problem if the measured noise is lower than the target noise. Therefore, when the measured noise is lower than the approximate range of the target noise, the driving capability of the driving circuit 250 may be maintained at its current state without being increased.

[0032] Next, in step S4, the drive capacity determination unit 3 provides the determined target drive capacity to the drive capacity adjustment unit 12. The drive capacity adjustment unit 12 adjusts the drive capacity of the drive circuit 250 so that the drive capacity of the drive circuit 250 becomes the target drive capacity from the drive capacity determination unit 3. Thereafter, the noise acquisition unit 1 returns to the processing of step S1.

[0033] The noise acquisition unit 1, noise judgment unit 2, and drive capability determination unit 3 repeat the processes of steps S1 to S4 until the measured noise approximates the target noise in step S2. When the measured noise approximates the target noise, the design assistance process ends.

[0034] As described above, in the first embodiment, it is determined whether or not the measured noise detected by the noise detection unit 11 is within the target range, and if the measured noise is not within the target range, the target driving capacity is determined. In this case, the target driving capacity is determined based on the noise actually generated by the power conversion device 200, and therefore the driving capacity of the drive circuit 250 can be adjusted more efficiently and with higher accuracy than when the driving capacity of the drive circuit 250 is adjusted based solely on analysis. This makes it possible to shorten the time required to design the power conversion device and suppress increases in development costs.

[0035] Embodiment 2 The design assistance device, design assistance system, and design assistance method according to the second embodiment will be described, focusing on the differences from the design assistance device, design assistance system, and design assistance method according to the first embodiment.

[0036] Fig. 4 is a block diagram showing the configuration of a design assistance system according to embodiment 2. The design assistance system 1000a in Fig. 4 differs from the design assistance system 1000 in Fig. 1 in that the design assistance system 1000a includes a design assistance device 100a instead of the design assistance device 100 in Fig. 1, and further includes a countermeasure component presenting unit 13. The design assistance device 100a differs from the design assistance device 100 in Fig. 1 in that the design assistance device 100a further includes a countermeasure component determining unit 5.

[0037] If the converter noise is not within the target range, the countermeasure component determination unit 5 determines a countermeasure component that is a component to be added to the power conversion device 200. For example, the countermeasure component determination unit 5 determines a countermeasure component if the converter noise does not fall within the target range even after the driving capability of the drive circuit 250 is adjusted. The countermeasure component presentation unit 13 presents the countermeasure component determined by the countermeasure component determination unit 5 to the user. The countermeasure component presentation unit 13 is, for example, a display device, and presents the countermeasure component to the user as an image.

[0038] Figures 5 and 6 are flowcharts of the design support processing by the design support system 1000a according to embodiment 2. The design support processing in Figures 5 and 6 differs from the design support processing in Figure 3 in that steps S10 to S24 shown below are performed instead of steps S3 and S4 in Figure 3.

[0039] In step S10, the driving capability determination unit 3 determines whether the number of times the process of step S10 has been performed has reached a specified number. The number of times the process of step S10 has been performed corresponds to the number of times it was determined in step S2 that the converter noise is not close to the target noise. If the number of times the process of step S10 has been performed has not reached the specified number, the driving capability determination unit 3 proceeds to step S11.

[0040] In step S11, the driving capability determination unit 3 determines the target driving capability so that the measured noise approaches the target noise, similar to the process in step S3 of FIG.

[0041] Next, in step S12, the drive capacity determination unit 3 calculates, by simulation, a switching waveform of the semiconductor switching element 240 when the drive circuit 250 drives the semiconductor switching element 240 at the target drive capacity determined in step S3. As described above, the switching waveform of the semiconductor switching element 240 changes in accordance with changes in the drive capacity of the drive circuit 250. If the operating conditions of the power conversion device 200 are known, the switching waveform of the semiconductor switching element 240 can be calculated based on the drive capacity of the drive circuit 250.

[0042] Next, in step S13, the drive capability determination unit 3 determines whether or not parameters of the power conversion device 200 other than the converter noise (hereinafter referred to as non-noise parameters) are within a predetermined allowable range based on the switching waveform calculated in step S12. The non-noise parameters are, for example, at least one of a surge voltage in the power conversion circuit 210, a loss in the semiconductor switching element 240, and a heat value of the semiconductor switching element 240.

[0043] The surge voltage includes a turn-off surge voltage and a recovery surge voltage. The surge voltage can be determined from the peak of the voltage change represented by the switching waveform.

[0044] The losses of the semiconductor switching element include the switching loss of the semiconductor switching element 240 and the conduction loss of the semiconductor switching element 240. The switching loss of the semiconductor switching element 240 can be calculated from the operating conditions of the power conversion device 200, and the product of the voltage and current of the switching waveform and the time ratio. In addition, the conduction loss of the semiconductor switching element 240 can be calculated from the current flowing through the semiconductor switching element 240, the voltage drop characteristics of the semiconductor switching element 240, and the conduction time.

[0045] The heat generation amount of semiconductor switching element 240 can be calculated from the loss of semiconductor switching element 240, the thermal resistance of semiconductor switching element 240 and a heat dissipation system such as a heat sink, and the ambient temperature. For example, the junction temperature of semiconductor switching element 240 can be calculated from this information.

[0046] For example, the drive capability determination unit 3 determines whether the junction temperature and surge voltage of the semiconductor switching element 240 exceed the absolute maximum ratings of the semiconductor switching element 240. The drive capability determination unit 3 also determines whether the loss of the semiconductor switching element 240 is within a range that allows the efficiency required for the power conversion device to be achieved.

[0047] If the non-noise parameters are not within the allowable range, the driving capability determination unit 3 proceeds to step S 14. In step S 14, the driving capability determination unit 3 updates the target driving capability so that the non-noise parameters fall within the allowable range.

[0048] For example, if the surge voltage is high, the surge voltage can be reduced by reducing the driving capability of the drive circuit 250 and reducing the switching speed of the semiconductor switching element 240. Also, if the loss of the semiconductor switching element 240 is large, the driving capability of the drive circuit 250 can be increased and the switching speed of the semiconductor switching element 240 can be increased, thereby reducing the loss of the semiconductor switching element 240. Also, if the amount of heat generated by the semiconductor switching element 240 is large, the driving capability of the drive circuit 250 can be increased and the switching speed of the semiconductor switching element 240 can be increased, thereby reducing the amount of heat generated by the semiconductor switching element 240. After updating the target driving capability, the driving capability determination unit 3 returns to step S12.

[0049] If the non-noise parameters are within the allowable range in step S13, the drive capacity determination unit 3 proceeds to step S15. In step S15, the drive capacity determination unit 3 provides the target drive capacity to the drive capacity adjustment unit 12. The drive capacity adjustment unit 12 adjusts the drive capacity of the drive circuit 250 based on the target drive capacity from the drive capacity determination unit 3. After adjusting the drive capacity of the drive circuit 250, the noise acquisition unit 1 returns to step S1 and detects the converter noise again.

[0050] Even if the non-noise parameters fall within the allowable range in step S13, there is a possibility that the measured noise will not approximate the target noise when step S2 is performed again. Steps S10 to S15 are repeated until the non-noise parameters fall within the allowable range in step S13 and the measured noise approximates the target noise in step S2. However, there is a limit to how much the driving capability of the driving circuit 250 can be adjusted. There are cases where both the conditions of step S13 and step S2 cannot be met by simply adjusting the driving capability of the driving circuit 250. Therefore, when the number of times the process of step S10 has been performed reaches a specified number of times, the countermeasure component determination unit 5 proceeds to step S16.

[0051] In step S16, the countermeasure component determination unit 5 determines the countermeasure components to be added to bring the measured noise closer to the target noise. For example, information representing the correspondence between the difference between the measured noise and the target noise and the countermeasure components is stored in advance, and the countermeasure components are selected based on that information. Alternatively, a circuit simulator is used to calculate the converter noise when various countermeasure components are added, and the countermeasure components that bring the converter noise closest to the target noise are selected. The countermeasure components are, for example, a ferrite core around which a wire can be wound, a ferrite core clamped to a wire, or an electromagnetically shielded wire or shield plate.

[0052] Next, in step S17, the countermeasure component determination unit 5 issues a presentation command to present the determined countermeasure components to the countermeasure component presentation unit 13, so that the countermeasure component presentation unit 13 presents the countermeasure components to the user. This completes the design support process.

[0053] The user can bring the converter noise closer to the target noise by adding the presented countermeasure components to the power conversion device 200. The countermeasure components determined in step S16 may be automatically added to the power conversion device 200 by a robot or the like. After the countermeasure components are added, the design support processes of FIGS. 5 and 6 may be performed again.

[0054] As described above, in the second embodiment, a switching waveform corresponding to the determined target driving capability is calculated, and whether or not the non-noise parameters are within the allowable range is determined based on the switching waveform. If the non-noise parameters are not within the allowable range, the target driving capability is updated. This allows the driving capability of the driving circuit 250 to be adjusted so that not only the converter noise is within the target range, but also the non-noise parameters are within the allowable range. As a result, a power conversion device that meets various requirements can be efficiently designed.

[0055] Furthermore, in the second embodiment, if the converter noise does not fall within the target range even after the drive capacity of the drive circuit 250 is adjusted, a countermeasure component to be added is determined. In this case, even if the requirement cannot be met by adjusting the drive capacity of the drive circuit 250 alone, the requirement can be easily met by adding a countermeasure component. This makes it possible to shorten the time required to design a power conversion device and suppress increases in the development costs of the power conversion device.

[0056] In this embodiment, the process shifts from adjusting the driving capacity to determining a countermeasure component based on the number of times step S10 is performed, but the present invention is not limited to this. For example, the process may select whether to shift to adjusting the driving capacity or to determining a countermeasure component based on the magnitude of the difference between the actual noise and the target noise. Alternatively, the user may select which process to perform when the actual noise is not within the target range.

[0057] 5 and 6, verification of non-noise parameters (steps S12 to S14) does not have to be performed. In this case, surges, switching losses, etc. need to be separately considered, but it is possible to adjust the driving capability of the driving circuit 250.

[0058] Embodiment 3 The design assistance device, design assistance system, and design assistance method according to the third embodiment will be described, focusing on the differences from the design assistance device, design assistance system, and design assistance method according to the second embodiment.

[0059] Fig. 7 is a block diagram showing the configuration of a design assistance system according to embodiment 3. The design assistance system 1000b in Fig. 7 differs from the design assistance system 1000a in Fig. 4 in that the design assistance system 1000b includes a design assistance device 100b instead of the design assistance device 100a in Fig. 4. The design assistance device 100b differs from the design assistance device 100a in Fig. 4 in that the design assistance device 100b includes a noise determination unit 2a instead of the noise determination unit 2, and further includes a model information acquisition unit 6, a model generation unit 7, a noise estimation unit 8, and a model correction unit 10.

[0060] The model information acquiring unit 6 acquires model information of the power conversion device 200. The model information is information necessary for generating a noise model, which will be described later, and includes multiple pieces of characteristic information of the power conversion device 200. The characteristic information includes, for example, the switching waveforms of the semiconductor switching elements, artwork of the printed wiring board constituting the power conversion circuit 210, wiring, a motor, and a model of the housing of the power conversion device 200. The characteristic information may include the characteristics and switching conditions of the semiconductor switching elements, the operating conditions of the power conversion device 200, information on components such as reactors and capacitors included in the power conversion device 200, and information on the propagation path to the noise observation point.

[0061] The model information acquisition unit 6 acquires, for example, model information input by a user or model information obtained from an external server via the Internet.

[0062] The model generation unit 7 generates a noise model that is a model of converter noise. The noise model includes a noise source model and a noise propagation characteristic model. The noise source model is a model that represents the source of converter noise (hereinafter referred to as the noise source). The noise propagation characteristic model is a model that represents the propagation characteristics of converter noise from the noise source to the noise observation point (hereinafter referred to as the noise propagation characteristic).

[0063] The noise source is mainly the semiconductor switching element 240. When the semiconductor switching element 240 is turned on or off, noise is generated by a sudden change in the voltage applied between the positive and negative electrodes and a sudden change in the current flowing between the positive and negative electrodes.

[0064] The noise source model can be obtained from the switching waveform of the semiconductor switching element. For example, by creating a circuit model using a circuit simulator and performing waveform analysis of the voltage and current of the semiconductor switching element, it is possible to generate the noise source model without actually manufacturing the power conversion device 200. It is preferable to use actual measurement data of the switching waveform of the semiconductor switching element 240 included in the actual power conversion device 200 as the switching waveform. Using the switching waveform of the actual semiconductor switching element 240 prevents the occurrence of errors.

[0065] The noise propagation characteristics depend on the noise propagation path from the noise source to the noise observation point (hereinafter referred to as the noise propagation path.) The noise propagation path includes, for example, the components that make up the power conversion device 200, as well as the components or space between the power conversion device 200 and the noise observation point. The noise propagation characteristic model can be generated, for example, by performing electromagnetic field analysis using artwork of the printed wiring board that constitutes the power conversion circuit 210 and a model of the housing of the power conversion device 200, without actually manufacturing the power conversion device 200.

[0066] The noise estimation unit 8 estimates the converter noise based on the noise model generated by the model generation unit 7. For example, the noise estimation unit 8 can estimate the converter noise observed at a specific noise observation point by electromagnetic field analysis using a noise source model and a noise propagation characteristics model. In the following description, the converter noise estimated by the noise estimation unit 8 will be referred to as estimated noise.

[0067] The model corrector 10 corrects the noise model generated by the model generator 7 based on the measured noise. In this example, the model corrector 10 corrects the noise model so that the estimated noise approaches the measured noise. The model corrector 10 also corrects the noise model based on the driving capability of the drive circuit 250 changed by the driving capability adjuster 12. The model corrector 10 also corrects the noise model based on the countermeasure component determined by the countermeasure component determiner 5.

[0068] 7 determines whether the estimated noise is similar to the actually measured noise, and if so, determines whether the estimated noise or the actually measured noise is within the target range. If the estimated noise is similar to the actually measured noise, the determination result of whether the estimated noise or the actually measured noise is within the target range is the same regardless of whether the estimated noise or the actually measured noise is used.

[0069] In this example, if the estimated noise is close to the measured noise, the noise determination unit 2a performs a close determination between the estimated noise and the target noise. In this case, the close range of the target noise corresponds to the target range. Instead of performing the close determination between the estimated noise and the target noise, a determination may be made as to whether the estimated noise is equal to or less than a predetermined target value. In this case, the range equal to or less than the target value corresponds to the target range.

[0070] 8, 9, and 10 are flowcharts of the design support process by the design support system 1000b according to the third embodiment.

[0071] In step S31, the model information acquisition unit 6 acquires model information of the power conversion device 200. Next, in step S32, the model generation unit 7 generates a noise model based on the model information acquired in step S31. For example, the model generation unit 7 generates a noise source model based on the switching waveform of the semiconductor switching element 240, which is included in the model information. Furthermore, the model generation unit 7 generates a noise propagation characteristic model based on information on the artwork and housing of the printed wiring board, which is included in the model information acquired in step S31.

[0072] Next, in step S33, the noise estimation unit 8 estimates the converter noise observed at the noise observation point based on the noise model generated in step S32.

[0073] Next, in step S34, the noise acquisition unit 1 acquires the converter noise detected by the noise detection unit 11 as the actually measured noise.

[0074] Next, in step S35, the noise determination unit 2a determines whether the estimated noise estimated in step S33 is similar to the measured noise acquired in step S34. If the estimated noise is within the approximation range of the measured noise, the noise determination unit 2a determines that the estimated noise is similar to the measured noise. If the estimated noise is not within the approximation range of the measured noise, the noise determination unit 2a determines that the estimated noise is not similar to the measured noise. The determination in step S35 may be performed only within a specific frequency range.

[0075] If the estimated noise is not approximate to the actually measured noise, the model corrector 10 proceeds to step S36. In step S36, the model corrector 10 corrects the noise model generated in step S32 so that the estimated noise approaches the actually measured noise. Specifically, the model corrector 10 calculates a correction amount for the noise model based on the noise source model and noise propagation characteristic model generated in step S32, the estimated noise estimated in step S33, and the actually measured noise input in step S34, and corrects the noise model using the calculated correction amount. The correction in step S36 may be performed only within a specific frequency range.

[0076] In step S32, errors in the noise source model are unlikely to occur when the noise source model is generated using the actual switching waveform of the semiconductor switching element 240. Therefore, in step S35, only the noise propagation characteristic model may be corrected.

[0077] Once the noise model has been corrected in step S36, the noise estimation unit 8 returns to step S33 and re-estimates the converter noise based on the corrected noise model.

[0078] If the estimated noise is approximate to the actually measured noise in step S35, the noise determination unit 2a proceeds to step S37. In step S37, the noise determination unit 2a determines whether the estimated noise is approximate to the target noise. Specifically, the noise determination unit 2a determines whether the estimated noise is within the approximation range of the target noise. If the estimated noise is within the approximation range of the target noise, the noise determination unit 2a determines that the estimated noise is approximate to the target noise. If the estimated noise is not within the approximation range of the target noise, the noise determination unit 2a determines that the estimated noise is not approximate to the target noise. The determination in step S37 may be performed only within a specific frequency range.

[0079] If the estimated noise is not approximate to the target noise, the driving capability determination section 3 proceeds to step S38. The processes of steps S38 to S43 are the same as the processes of steps S10 to S15 in FIG.

[0080] In step S43, when the driving capability of the drive circuit 250 is changed by the driving capability adjustment unit 12, the model correction unit 10 proceeds to step S44. The model correction unit 10 corrects the noise model to correspond to the driving capability after the change in step S43. For example, the model correction unit 10 corrects the noise source model based on the switching waveform calculated in step S40. In this case, the noise source model can be corrected to correspond to the changed driving capability. Furthermore, after the driving capability of the drive circuit 250 is changed, the switching waveform of the semiconductor switching element 240 may be measured from the power conversion device 200, and the noise source model may be corrected based on the switching waveform.

[0081] After the noise model is corrected in step S44, the noise estimation unit 8 returns to step S33 and re-estimates the converter noise based on the corrected noise model.

[0082] When the number of times of processing in step S38 reaches the specified number of times, the countermeasure component determination unit 5 proceeds to step S45. In step S45, the countermeasure component determination unit 5 determines countermeasure components to be added, similar to step S16 in FIG.

[0083] Next, in step S46, the model corrector 10 corrects the noise model based on the countermeasure component determined in step S44. For example, when a countermeasure component is added to the power conversion device 200, the propagation characteristics of the converter noise change. Therefore, the model corrector 10 calculates the noise propagation characteristics when the determined countermeasure component is used, and corrects the noise propagation characteristic model based on the calculated propagation characteristics.

[0084] Next, in step S47, the noise estimation unit 8 re-estimates the converter noise based on the noise model corrected in step S46. Next, in step S48, the countermeasure component determination unit 5 determines whether the estimated noise estimated in step S46 is within a target range. The target range may be an approximate range of the target noise, or may be a range equal to or less than the target value.

[0085] If the estimated noise is not within the target range, the countermeasure component determination unit 5 returns to step S45 and determines a countermeasure component again. In this case, another countermeasure component may be determined instead of the previously determined countermeasure component, or another countermeasure component may be determined in addition to the previously determined countermeasure component.

[0086] If the estimated noise is within the target range in step S48, the countermeasure component determination unit 5 proceeds to step S49. In step S49, the countermeasure component determination unit 5 issues a presentation command to present the determined countermeasure component to the countermeasure component presentation unit 13, so that the countermeasure component presentation unit 13 presents the countermeasure component to the user. This completes the design support process.

[0087] As described above, in the third embodiment, it is determined whether the estimated noise estimated based on the noise model is similar to the measured noise. If the estimated noise is similar to the measured noise, it is determined whether the estimated noise or the measured noise is within a target range. If the estimated noise or the measured noise is not within the target range, a target driving capacity is determined. In this way, the target driving capacity is determined based on the estimated noise estimated from the noise model and the measured noise, so that the driving capacity of the driving circuit 250 can be adjusted with higher accuracy. Furthermore, because a noise model is generated, the converter noise can be estimated from the noise model even when an actual power conversion device 200 is not available. Therefore, the converter noise can be easily verified.

[0088] Furthermore, in the third embodiment, if the estimated noise is not close to the measured noise, the noise model is corrected based on the measured noise. In this case, the use of the measured noise makes it possible to generate a noise model with higher accuracy than a noise model generated using only analysis or simulation. As a result, the converter noise can be estimated with high accuracy.

[0089] Furthermore, in the third embodiment, when the driving capability of the driving circuit 250 is changed, the noise model is corrected based on the changed driving capability. Furthermore, when a countermeasure component is determined, the noise model is corrected based on the determined countermeasure component. In this way, the noise model is updated in response to changes in various conditions, so that the converter noise under the changed conditions can be estimated with high accuracy.

[0090] In the third embodiment, if the estimated noise or the measured noise is not within the target range, a process for adjusting the driving capability (steps S39 to S44) or a process for determining a countermeasure component (steps S45 to S49) is carried out, as in the second embodiment, but one or both of these processes may not be carried out.

[0091] Embodiment 4 The design assistance device, design assistance system, and design assistance method according to the fourth embodiment will be described, focusing on the differences from the design assistance device, design assistance system, and design assistance method according to the third embodiment.

[0092] FIG. 11 is a block diagram showing the configuration of a design assistance system according to the fourth embodiment.

[0093] In this embodiment, power conversion device 200 includes a plurality of noise sources having different characteristics. Specifically, power conversion device 200 in Fig. 11 includes power conversion circuits 210A and 210B. For example, power conversion circuit 210A is a DC-DC converter that converts the voltage of input DC power and outputs the DC power after the voltage conversion, and power conversion circuit 210B is an inverter that converts the DC power output by power conversion circuit 210A into AC power and outputs the converted AC power.

[0094] The power conversion circuit 210A has a semiconductor switching element 240A and a drive circuit 250A that drives the semiconductor switching element 240A. The power conversion circuit 210B has a semiconductor switching element 240B and a drive circuit 250B that drives the semiconductor switching element 240B. In this case, each of the semiconductor switching elements 240A of the power conversion circuit 210A and each of the semiconductor switching elements 240B of the power conversion circuit 210B become noise sources.

[0095] In the example of FIG. 11, a plurality of power conversion circuits 210A and 210B are provided as a plurality of noise sources, but a plurality of noise sources with different characteristics may be included in one power conversion circuit.

[0096] The noise detection unit 11 detects the overall converter noise of the power conversion device 200. Therefore, the actually measured noise includes the converter noise of the power conversion circuit 210A and the converter noise of the power conversion circuit 210B.

[0097] 7 in that the design support system 1000c includes a design support device 100c instead of the design support device 100b of FIG. 7, and includes drive capacity adjustment units 12A and 12B instead of the drive capacity adjustment unit 12. The design support device 100c differs from the design support device 100b in that the design support device 100c includes a noise estimation unit 8a instead of the noise estimation unit 8, and a drive capacity determination unit 3a instead of the drive capacity determination unit 3.

[0098] The drive capacity adjusting units 12A and 12B correspond to the drive circuits 250A and 250B, respectively, and are configured to be able to adjust the drive capacity of the corresponding drive circuits.

[0099] The noise estimation unit 8a estimates the converter noise of each of the multiple noise sources based on the noise model generated by the model generation unit 7. In this example, the noise estimation unit 8a estimates the converter noise of each of the power conversion circuits 210A and 210B.

[0100] Drive capacity determination unit 3a determines which of drive circuits 250A, 250B should have its drive capacity adjusted, based on the measured noise acquired by noise acquisition unit 1 and the estimated nozzle of each noise source estimated by noise estimation unit 8a. Drive capacity determination unit 3a determines a target drive capacity for the drive circuit whose drive capacity it has determined should be adjusted, and provides the determined target drive capacity to one of drive capacity adjustment units 12A, 12B that corresponds to the determined drive circuit.

[0101] The drive capability determiner 3a may determine the drive circuit whose drive capability should be adjusted based on the distribution of converter noise with respect to frequency. For example, the measured noise is assumed to be within the approximate range of the target noise in a first frequency band and to be greater than the approximate range of the target noise in a second frequency band different from the first frequency band. Furthermore, the distribution of the estimated noise of the power conversion circuit 210A tends to be large in the first frequency band, and the distribution of the estimated noise of the power conversion circuit 210B tends to be large in the second frequency band.

[0102] In this case, by reducing the converter noise of the power conversion circuit 210B, the converter noise in the second frequency band of the actually measured noise can be made closer to the target noise. Therefore, the drive capability determiner 3a determines that the drive capability of the drive circuit 250B of the power conversion circuit 210B should be adjusted, and provides the target drive capability of the drive circuit 250B to the drive capability adjuster 12B.

[0103] In this way, in the fourth embodiment, the drive capabilities of the drive circuits corresponding to the multiple noise sources are selectively adjusted based on the estimated noises of the multiple noise sources, thereby enabling the converter noise of the entire power conversion device 200 to be efficiently adjusted to the target noise.

[0104] Furthermore, selectively adjusting the drive capabilities of the multiple drive circuits increases the degree of freedom in adjusting the converter noise of the entire power conversion device 200. For example, as described above, when the noise distribution with respect to frequency differs depending on the noise source, the magnitude of the converter noise of the entire power conversion device 200 can be adjusted for each frequency band by selectively adjusting the drive capabilities of the multiple drive circuits. This makes it possible to easily adjust the converter noise of the entire power conversion device 200 for each frequency band even when the degree of agreement between the measured noise and the estimated noise is not high.

[0105] 12 is a diagram showing an example in which at least some of the functions of the design assistance devices 100, 100a, and 100b are realized by software. In the example of FIG. 12, the design assistance device 100 includes a processing unit (processor) 501 and a storage device (memory) 502. The processing unit 501 is, for example, a CPU (central processing unit), and can realize the functions of the design assistance devices 100, 100a, and 100b by reading and executing programs stored in the storage device 502. The processing unit 501 may be an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), or the like. The storage device 502 may be a read-only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), or the like.

[0106] Other embodiments. In the above-described first to fourth embodiments, the drive capacity adjustment unit 12 adjusts the drive capacity of the drive circuit 250 based on the target drive capacity determined by the drive capacity determination unit 3, but the present invention is not limited to this. For example, the target drive capacity determined by the drive capacity determination unit 3 may be presented to a user, and the user may adjust the drive capacity of the drive circuit 250 based on the presented target drive capacity. [Explanation of symbols]

[0107] 1 Noise acquisition section 2,2a Noise detection section 3,3a Drive capacity determination section 5. Countermeasure parts determination section 6 Model information acquisition section 7 Model Generation Unit 8 Noise Estimation Unit 10 Model correction section 11 Noise detection section 12, 12A, 12B Drive capacity adjustment section 13 Countermeasure parts presentation section 100,100a,100b,100c Design support equipment 200 Power conversion device 240, 240A, 240B Semiconductor switching element 250, 250A, 250B drive circuit 1000, 1000a, 1000b Design Support System

Claims

1. A design assistance device that assists in the design of a power conversion device having a semiconductor switching element and a drive circuit that drives the semiconductor switching element, a noise acquisition unit that acquires a detection result of converter noise, which is noise generated from the power conversion device, as actual noise; a noise determination unit that determines whether the converter noise is within a predetermined target range based on the measured noise acquired by the noise acquisition unit; a drive capacity determination unit that, when the converter noise is not within the target range, determines a target drive capacity that is a target for adjusting the drive capacity of the drive circuit, determines whether or not non-noise parameters, which are parameters of the power conversion device other than the converter noise, are within a predetermined allowable range based on a switching waveform of the semiconductor switching element when the drive circuit drives the semiconductor switching element at the determined target drive capacity, and updates the determined target drive capacity so that the non-noise parameters fall within the allowable range when the non-noise parameters are not within the allowable range; A design assistance device comprising:

2. the non-noise parameters include at least one of a surge voltage, a loss in the semiconductor switching element, and a heat generation amount of the semiconductor switching element; The design assistance device according to claim 1 .

3. A design assistance device that assists in the design of a power conversion device having a semiconductor switching element and a drive circuit that drives the semiconductor switching element, a noise acquisition unit that acquires a detection result of converter noise, which is noise generated from the power conversion device, as actual noise; a noise determination unit that determines whether the converter noise is within a predetermined target range based on the measured noise acquired by the noise acquisition unit; a drive capacity determination unit that determines a target drive capacity as a target for adjusting the drive capacity of the drive circuit when the converter noise is not within the target range; a countermeasure component determination unit that determines a countermeasure component that is a component to be added to the power conversion device when the converter noise is not within the target range; A design assistance device comprising:

4. the countermeasure component determination unit determines the countermeasure component when the converter noise does not fall within the target range even after the driving capability of the driving circuit is adjusted. The design assistance device according to claim 3.

5. A design assistance device that assists in the design of a power conversion device having a semiconductor switching element and a drive circuit that drives the semiconductor switching element, a noise acquisition unit that acquires a detection result of converter noise, which is noise generated from the power conversion device, as actual noise; a noise determination unit that determines whether the converter noise is within a predetermined target range based on the measured noise acquired by the noise acquisition unit; a noise estimation unit that estimates the converter noise based on a noise model that is a model of the converter noise; a drive capacity determination unit that determines a target drive capacity as a target for adjusting the drive capacity of the drive circuit when the converter noise is not within the target range; Equipped with the noise determination unit determines whether or not estimated noise, which is noise estimated by the noise estimation unit, is approximate to the actually measured noise, and if the estimated noise is approximate to the actually measured noise, determines whether or not the estimated noise or the actually measured noise is within the target range; the drive capacity determination unit determines the target drive capacity when the estimated noise or the measured noise is not within the target range. Design aids.

6. further comprising a model correction unit that corrects the noise model based on the measured noise when the estimated noise is not approximate to the measured noise; The design assistance device according to claim 5.

7. A design assistance device that assists in the design of a power conversion device having a plurality of semiconductor switching elements and a plurality of drive circuits that drive the plurality of semiconductor switching elements, comprising: a noise acquisition unit that acquires a detection result of converter noise, which is noise generated from the power conversion device, as actual noise; a noise estimation unit that estimates the converter noise based on a noise model that is a model of the converter noise; a noise determination unit that determines whether the converter noise is within a predetermined target range based on the measured noise acquired by the noise acquisition unit; a drive capability determination unit that, when the converter noise is not within the target range, determines a target drive capability that is a target for adjusting the drive capability of the drive circuit, determines which of the plurality of drive circuits should have its drive capability adjusted based on the noise estimated by the noise estimation unit, and determines the target drive capability of the drive circuit that has been determined to have its drive capability adjusted; Design aids.

8. A design assistance device according to any one of claims 1 to 7; a drive capacity adjustment unit that adjusts the drive capacity of the drive circuit based on the target drive capacity determined by the drive capacity determination unit; A design support system comprising:

9. A design assistance method for assisting the design of a power conversion device having a semiconductor switching element and a drive circuit that drives the semiconductor switching element, comprising: a step of acquiring a detection result of converter noise, which is noise generated from the power conversion device, as actual measured noise; determining whether the converter noise is within a predetermined target range based on the measured noise acquired by a noise acquisition unit; determining a target driving capability as a target for adjusting the driving capability of the driving circuit when the converter noise is not within the target range; determining whether or not non-noise parameters, which are parameters of the power conversion device other than the converter noise, are within a predetermined allowable range based on a switching waveform of the semiconductor switching element when the drive circuit drives the semiconductor switching element at the determined target drive capacity, and if the non-noise parameters are not within the allowable range, updating the determined target drive capacity so that the non-noise parameters are within the allowable range; adjusting the driving capability of the driving circuit based on the determined target driving capability; A design assistance method comprising:

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