Motor drive control device for a vehicle

Abstract

[Task] Both weight reduction and electromagnetic wave shielding are being implemented. [Solution] A motor drive control device 1 for a vehicle is provided with a power module 10, which controls the power of an electric motor that drives the vehicle, a first cover 30, which is open at one surface and is designed in the form of a cylindrical box with a bottom and is arranged such that it covers the power module, and a second cover 40, which closes an opening of the first cover, wherein in the second cover a first component 41 made of iron with a thickness of 0.3 mm to 0.5 mm and a second component 42 made of aluminum with a thickness of 0.3 mm or more are stacked such that a space is provided between the first component and the second component.

Description

[Technical field]

[0001] The present invention relates to an electromagnetic wave shield for a motor drive control device for a vehicle. [Technical background]

[0002] Generally, vehicles such as motor vehicles contain electronic components (electrical components) for various purposes, such as propulsion and control. An electromagnetic wave shielding technology is known in which the electromagnetic waves generated by the electrical components are blocked within their housings (see, for example, patent document 1). [State of the art document][Patent document]

[0003] [Patent Document 1] JP 5735583 B2 [Summary of the invention][Problem to be solved by the invention]

[0004] In motor vehicles with an electric drive source, a motor drive control device, known as a Power Control Unit (PCU), is installed to control the drive motor. Inside the PCU's housing are various electronic components, including an inverter that converts direct current (DC) to alternating current (AC) (power module), a capacitor that smooths the electrical power from the battery, and a control circuit board that forms a circuit controlling the operation of the PCU, which contains the inverter.

[0005] Just as with the aforementioned electronic components for a vehicle, improved electromagnetic wave shielding is also required for PCUs. Specifically, the task involves shielding electromagnetic waves generated by a PCU in a frequency range of 0.5 MHz to 1 MHz, which corresponds to the frequencies of AM radios.

[0006] On the other hand, the demands for weight reduction are increasing for PCUs, including the housing. If one considers only electromagnetic wave shielding performance, it is effective to use a thick aluminum material for the entire housing, but this increases the PCU's weight.

[0007] The present invention was therefore created taking into account the above problem and aims to provide a motor drive control device for a vehicle that can effect both weight reduction and electromagnetic wave shielding performance. [Means of solving the problem]

[0008] To solve the above problem, a motor drive control device for a vehicle according to the present invention is provided with a power module that controls the power of an electric motor that drives the vehicle, a first cover which is open at one surface and is designed in the form of a cylindrical box with a bottom and is arranged such that it covers the power module, and a second cover which closes an opening of the first cover, wherein in the second cover a first component made of iron with a thickness of 0.3 mm to 0.5 mm and a second component made of aluminum with a thickness of 0.3 mm or more are stacked such that a space is provided between the first component and the second component.

[0009] In the motor drive control device for a vehicle according to an embodiment of the present invention, the second cover has a shielding effect of at least 40 dB against electromagnetic waves from 0.5 MHz to 1 MHz.

[0010] In the motor drive control device for a vehicle according to an embodiment of the present invention, in the second cover the first component made of iron is arranged closer to the power module than the second component made of aluminum. [Advantages of the invention]

[0011] According to the present invention, a motor drive control device for a vehicle can be provided in which both weight reduction and electromagnetic wave shielding performance can be achieved. [Brief description of the drawings] [ Fig. Figure 1] is a sectional view showing a motor drive control device for a vehicle according to an embodiment of the present invention. [ Fig. 2] is an enlarged sectional view showing a second cover of the motor drive control device for a vehicle according to the present embodiment. [ Fig. Figure 3] is an enlarged sectional view showing a modified example of the second cover in the motor drive control device for a vehicle according to the present embodiment. [ Fig. Figure 4] is a view that schematically shows the effect of the electromagnetic wave shielding by the second cover in the motor drive control device for a vehicle according to the present embodiment. [ Fig. Figure 5] is a diagram showing the difference in electromagnetic wave shielding performance due to the difference in material. [Embodiments of the invention]

[0012] In the following, embodiments of the present invention are explained with reference to the drawings. [Overview of embodiments]

[0013] First, an overview of the representative embodiments of the invention disclosed in this application is explained. In the following explanation, the reference numerals in the drawings that correspond to the components of the invention are given in parentheses as an example. [1] Motor drive control device for a vehicle, equipped with a power module (10) that controls the power of an electric motor that drives the vehicle, a first cover (30) that is open at one surface and is designed in the form of a cylindrical box with a bottom and is arranged to cover the power module, and a second cover (40) that closes an opening of the first cover, wherein in the second cover a first component (41) made of iron with a thickness of 0.3 mm to 0.5 mm and a second component (42) made of aluminum with a thickness of 0.3 mm or more are stacked such that a space is provided between the first component and the second component. [2] Motor drive control device for a vehicle according to [1], wherein the second cover has a shielding effect of at least 40 dB against electromagnetic waves from 0.5 MHz to 1 MHz. [3] Motor drive control device for a vehicle according to [1] or [2], wherein in the second cover the first component made of iron is arranged closer to the power module than the second component made of aluminium. [Structure of the engine drive control device for a vehicle]

[0014] Fig. Figure 1 is a sectional view showing a motor drive control device 1 for a vehicle according to an embodiment of the present invention. Fig. Figure 2 is an enlarged sectional view showing a second cover 40 of the motor drive control device 1 for a vehicle.

[0015] For the sake of simplicity, the following explanation will describe the longitudinal direction of a line in the Fig. 1 and Fig. The motor drive control device 1 shown in Figure 2 for a vehicle is considered to have the x-axis direction (left-right direction, width direction) and the transverse direction perpendicular to the x-axis to the z-axis direction (up-down direction, height direction). When the following explanation describes the positional relationships or directions of the individual components as right side, left side, front side, rear side, top side, and bottom side, this merely illustrates the positional relationships or directions shown in the drawings and does not limit the positional relationships or directions of the actual motor drive control device 1 for a vehicle.

[0016] As in Fig. As shown in Figure 1, the motor drive control device 1 for a vehicle is mainly equipped with a power module 10, a water jacket 20, a first cover 30, a second cover 40 and a capacitor 50.

[0017] The power module 10 controls the power of an electric motor (not shown) that drives the vehicle. The power module 10 is, for example, a power semiconductor module device that uses Si (silicon) or SiC (silicon carbide) as the semiconductor material. Specifically, the power module 10 operates as an inverter that converts direct current to alternating current and vice versa. The power module 10 is electrically connected to the capacitor 50, which smooths the electrical power from a battery (not shown), via a busbar 60. In the power module 10, the surface of the lower side is considered a first surface 11 in the top-bottom direction, and the surface of the upper side is considered a second surface 12. Furthermore, in the present embodiment, the direction from the first surface 11 to the second surface 12, i.e., the upward direction, is considered the first direction, and the direction from the second surface 12 to the first surface 11, i.e.,the downward direction, considered as a second direction.

[0018] The water jacket 20 is made of synthetic resin and has an internal flow channel (not shown) through which a coolant such as LLC (Long Life Coolant) can circulate. In the water jacket 20, the surface of the lower side is considered a first surface 21 in the top-bottom direction, and the surface of the upper side is considered a second surface 22. Electronic components such as the power module 10, the capacitor 50, etc., are installed on the second surface 22 of the water jacket 20.

[0019] The first cover 30 is formed by a component made of aluminum. The first cover 30 covers the power module 10, the capacitor 50, and the second surface 22 of the water jacket 20 from the side of the second surface 12 of the power module 10. The first cover 30 has a box-like shape with an opening 31, the bottom of which is open. The first cover 30 incorporates a dust-resistant structure, with sealed connections to the water jacket 20 to protect the power module 10, the capacitor 50, etc. The shape of the first cover 30 is not limited to a box shape, as long as it can cover the power module 10, etc., from the top.

[0020] The second cover 40 is a component constructed in a plate-like or essentially plate-like form. The second cover 40 is attached in such a way that it closes the opening 31 of the first cover 30. The outer circumferential shape of the second cover 40 corresponds to the outermost part of the wall around the opening 31 of the first cover 30 and can be fixed to the z-axis end face of the wall, for example, by means of fixing devices such as screws, etc. In the motor drive control device 1 for a vehicle, the second cover 40 closes the box-shaped first cover 30, which has the opening 31, as well as the opening 31 from the outside of the first cover 30. Furthermore, in the motor drive control device 1 for a vehicle, the electronic components, such as the power module 10 or the capacitor 50, etc., are insulated from the outside of the first cover 30 and the second cover 40 by the first cover 30 and the second cover 40.

[0021] The second cover 40 has a first component 41 and a second component 42. As in Fig. As shown in Figure 2, the first component 41 is an iron plate, i.e., a sheet of iron material. The first iron component 41 has a thickness (dimension in the z-axis direction) t1 of 0.5 mm. The second component 42 is an aluminum plate, i.e., a sheet of aluminum material. The second aluminum component 42 has a thickness t2 of 0.3 mm. The second cover 40 has a space between the first component 41 and the second component 42, with the first component 41 and the second component 42 stacked in the z-axis direction. The first component 41 and the second component 42 can be formed in one piece by riveting or screwing, or they can be formed in such a way that the space is filled with a non-conductive material, e.g., adhesive, etc., and the space between the first component 41 and the second component 42 can be very small.

[0022] In the second cover 40, the first iron component 41 is positioned closer to the water jacket 20 and the power module 10 than the second aluminum component 42, i.e., closer to the inside of the first cover 30. According to this configuration, it is not the first iron component 41, but the second aluminum component 42 that comes into contact with the outside air, which is why it serves as a corrosion protection structure. In the second cover 40, the second component 42 can also be positioned closer to the water jacket 20 than the first component 41.

[0023] Fig. Figure 3 is an enlarged sectional view showing a modified example of the second cover 40B in the motor drive control device 1 for a vehicle. The second cover 40B in the Fig. The modified example shown in Figure 3 differs in the thickness t1 of the first iron component 41B from the thickness t1 of the first component 41 of the previously described second cover 40. Specifically, the thickness t1 of the first iron component 41B is 0.3 mm. As will be explained in detail later, the thickness t1 of the first iron component 41, 41B in the second cover 40, 40B of the motor drive control device 1 for a vehicle can range from 0.3 mm to 0.5 mm. [Effect of the engine drive control device for a vehicle]

[0024] Next, the effect of the above-described motor drive control device 1 on a vehicle will be explained.

[0025] As mentioned above, in the motor drive control device 1 for a vehicle, electronic components such as the power module 10 and the capacitor 50, etc., are housed in an interior formed by the first cover 30 and the second cover 40, both made of metal. In the motor drive control device 1 for a vehicle, the metal enclosure provides benefits such as protection of the electronic components from the ingress of dust and moisture, protection against damage from collisions, protection of high-voltage lines such as the busbar 60, etc., and shielding of connections, as well as protection against electromagnetic waves generated by the electronic components.

[0026] Especially when electromagnetic waves are generated by the electronic components of the motor drive control device 1 for a vehicle in a frequency range close to that required for the operation of televisions, radios, mobile phones, etc., electromagnetic wave shielding is important, as there is a possibility that this could have an impact such as communication interference with normal functions like broadcasting or sending and receiving communications.

[0027] The power module 10 installed in the motor drive control device 1 for a vehicle generates electromagnetic waves E during the DC / AC conversion of the electrical power from the battery (see Fig. 1) The electromagnetic waves E generated by the power module 10 contain waves close to the frequency range of AM radios. AM radios are generally installed in vehicles for the purpose of obtaining traffic information, etc., which is why it is important for the motor drive control device 1 of a vehicle that the electromagnetic waves E are suppressed by the power module 10. In the motor drive control device 1 of a vehicle, electronic components such as the power module 10 and the capacitor 50 are housed in an interior formed by the first cover 30 and the second cover 40, which are made of metal, thus providing electromagnetic wave shielding.

[0028] On the other hand, a weight reduction approach is also required for the motor drive control device 1 for a vehicle. Therefore, there is a risk that the overall weight of the motor drive control device 1 for a vehicle will increase if the thickness of the metal components used for the first cover 30 and the second cover 40 is adjusted solely with regard to electromagnetic wave shielding measures.

[0029] Therefore, in the motor drive control device 1 for a vehicle, the first component 41, 41B made of iron and the second component 42 made of aluminum are stacked in such a way that a space is provided between them in the second cover 40, 40B. The first component 41, 41B made of iron has a thickness t1 of 0.3 mm to 0.5 mm and the second component 42 made of aluminum has a thickness t2 of 0.3 mm.

[0030] The electromagnetic wave shielding effect of metal components is related to the specific electrical conductivity divided by the specific magnetic permeability and the specific electrical conductivity multiplied by the specific magnetic permeability of the metal material. The specific electrical conductivity divided by the specific magnetic permeability indicates the degree of electromagnetic wave reflection loss, with the higher the value, the greater the reflection loss. Furthermore, the specific electrical conductivity multiplied by the specific magnetic permeability indicates the degree of electromagnetic wave absorption loss, with the higher the value.For iron, the specific electrical conductivity divided by the specific magnetic permeability is 0.0017, and the reflection loss is small, while for aluminum, the specific electrical conductivity multiplied by the specific magnetic permeability is 17, and the absorption loss is large. For aluminum, the specific electrical conductivity divided by the specific magnetic permeability is 0.63, and the reflection loss is large, while for aluminum, the specific electrical conductivity multiplied by the specific magnetic permeability is 0.63, and the absorption loss is small compared to iron.

[0031] Fig. Figure 4 is a schematic representation of the effect of electromagnetic wave shielding by the second cover 40, 40B in the motor drive control device 1 for a vehicle. As shown in Fig. As shown in Figure 4, in the motor drive control device 1 for a vehicle, the electromagnetic waves E1 generated by the power module 10 are radiated into the first component 41, 41B, which is located closer to the power module 10 than the second component 42. The reflection loss is low and the absorption loss is high in the first component 41, 41B, where they are largely absorbed and attenuated. Electromagnetic waves E2, which have penetrated the first component 41, 41B, pass through the space between the first component 41, 41B and the second component 42 and are radiated into the second component 42, which is made of aluminum. The absorption loss in aluminum is low compared to iron, but the reflection loss is higher. Some of the electromagnetic waves E2 penetrate the second component 42, but half or more are reflected by the second aluminum component 42.Electromagnetic waves E3 reflected by the second component 42 are again directed into the first iron component 41, 41B, where they are largely absorbed and a portion is reflected. The present invention thus aims to achieve the effect that, by repeating multiple reflections between the first iron component 41, 41B and the second aluminum component 42 at the second cover 40, 40B, the electromagnetic waves are attenuated.

[0032] As above, the present invention intends that, in the motor drive control device 1 for a vehicle, the first component 41, 41B made of iron and the second component 42 made of aluminum are stacked in such a way that they have a space, the electromagnetic waves are dampened by the multiple reflection loss of the electromagnetic waves between the two materials due to the reflection loss and absorption loss properties they each possess, and thus the shielding effect of the electromagnetic waves is increased.

[0033] Fig. Figure 5 is a diagram showing the difference in shielding effect due to differences in shielding material. All of this data are results obtained under identical conditions using the Advantest method, a measurement method developed by Advantest Corporation. Fig. Figure 5 shows S1 the shielding performance of the assembly of the second cover 40 of the present invention described above, i.e., a case in which it is assembled by the first component 41 made of iron with a thickness t1 of 0.5 mm and the second component 42 made of aluminum with a thickness t2 of 0.3 mm, as well as a space. Figure 5 shows the shielding performance of the assembly of the second cover 40B described above, i.e., a case in which it is assembled by the first component 41B made of iron with a thickness t1 of 0.3 mm and the second component 42 made of aluminum with a thickness t2 of 0.3 mm, as well as a space. For comparison, Figure 5 shows the shielding performance of an aluminum sheet material with a thickness of 3 mm. Figure 5 shows the shielding performance of an iron sheet material with a thickness of 1.2 mm. Figure 5 shows the shielding performance of an iron sheet material with a thickness of 0.8 mm.

[0034] As in Fig.Figure 5 shows that in a comparison of S1 to S5, where the effect of an aluminum plate material with a thickness of 3 mm is demonstrated, S3 exhibits the best shielding performance. However, the shielding performance of S1, which is shown in Figure 5, is essentially identical to that of S3, despite the thinner plate thickness. If the threshold for shielding performance against electromagnetic waves from 0.5 MHz to 1 MHz, which is close to the frequency range of AM radios, is, for example, 40 dB, then both S3 and S1 exhibit a shielding performance of 40 dB or more.S2, where the shielding performance of the second cover 40B is shown, which has a design where the thickness of the iron plate has been reduced from 0.5 mm to 0.3 mm, also exhibits a shielding performance of 40 dB or more against electromagnetic waves from 0.5 MHz to 1 MHz.

[0035] In contrast, for S4 and S5, where the shielding performance of a plate material that is only an iron plate is shown, the shielding performance is low compared to S1 to S3 and does not reach 40 dB or more against electromagnetic waves from 0.5 MHz to 1 MHz, and in the confirmed range of plate thickness there were no major differences in shielding performance, even when the plate thickness is changed.

[0036] Consequently, according to the above-explained motor drive control device 1 for a vehicle, in the second cover 40, 40B, the first component 41, 41B made of an iron plate with a thickness t1 of 0.3 mm to 0.5 mm and the second component 42 made of an aluminum plate with a thickness t2 of 0.3 mm are stacked in such a way that they have a space, thereby providing a motor drive control device for a vehicle in which both a weight reduction and a shielding performance can be achieved.Regarding the shielding performance results of the second cover 40, 40B, data are only available for the second aluminum component 42 with a thickness of 0.3 mm, and no comparative data on the shielding performance of a case where the thickness was changed are available. However, it is generally known that the thickness of a material does not correlate with the reflection loss but does correlate with the absorption loss. It can be said that the shielding performance increases with the thickness of the plate. Therefore, based on the available results, it can be said that the desired effect can be achieved in the construction of the second cover 40, 40B if the plate thickness of the second aluminum component 42 is at least 0.3 mm or more.

[0037] Embodiments of the present invention have been described above, but the present invention is not limited to the embodiments described above and includes any embodiments contained in the outline of the present invention and the claims. Furthermore, the individual structures can optionally be combined as needed to achieve at least some of the effects mentioned above. For example, the shape, material, arrangement, size, etc., of the individual structures in the embodiments described above can be modified as needed, depending on the specific application of the present invention.

[0038] For example, in the motor drive control device 1 for a vehicle described above, an example was explained in which the electronic component in which the electromagnetic wave shielding measures are to be carried out is the power module 10, but an application is also possible apart from the power module 10.

[0039] For example, in the motor drive control device 1 for a vehicle described above, an example was explained in which the first cover 30 and the second cover 40 are box-shaped, but the shape of the first cover 30 and the second cover 40 is not limited to the example mentioned above.

[0040] For example, the components of the second cover 40, 40B of the present invention can also be used as covers for other openings in the housing.

[0041] For example, in the motor drive control device 1 described above for a vehicle, the distance of the space between the first component 41 and the second component 42 is not particularly limited. [List of reference symbols] 1 Motor drive control device for a vehicle 10 Power module 11, 21 First area 12, 22 Second area 20 Water coat 30 First Cover 31 Opening 40, 40B Second cover 41, 41B First component 42 Second component 50 Capacitor 60 busbar E, E1, E2, E3 electromagnetic waves QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 5735583 B2

[0003]

Claims

[1] Engine drive control device for a vehicle, equipped with a power module that controls the power of an electric motor that drives the vehicle, a first cover which is open at one surface and is designed in the form of a cylindrical box with a bottom and is arranged in such a way that it covers the power module, and a second cover that closes an opening in the first cover, wherein in the second cover a first component made of iron with a thickness of 0.3 mm to 0.5 mm and a second component made of aluminium with a thickness of 0.3 mm or more are stacked in such a way that a space is provided between the first component and the second component. [2] Motor drive control device for a vehicle according to claim 1, wherein the second cover has a shielding effect of at least 40 dB against electromagnetic waves from 0.5 MHz to 1 MHz. [3] Motor drive control device for a vehicle according to claim 1 or 2, wherein in the second cover the first component made of iron is arranged closer to the power module than the second component made of aluminium.

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