Power converter equipped with a cooling fan

Abstract

The power converter (3) functions as a wireless charging station (ground pad module) for supplying energy to a wireless charging device for an electric vehicle. The power converter comprises a magnetic subassembly (31) and an electronic subassembly (32), and heat dissipation means including a centrifugal fan (5) for cooling the magnetic subassembly and / or the electronic subassembly. The centrifugal fan (5), which has a fan wheel (51), transports air through at least one cutoff edge (55) to at least one exhaust port passage (56). The cutoff edge (55) has an angle with respect to the rotation axis (53) of the centrifugal fan (5) in the region (63) adjacent to the fan wheel (51), which will be hereafter referred to as the effective edge angle (k), in particular an effective edge angle (k) of at least 20°.

Description

Technical Field

[0001] The present invention relates to a power conversion device that converts the power of a supply current into the electromagnetic force of an oscillating electromagnetic field.

Background Art

[0002] A power conversion device includes not only a magnetic subassembly that receives electrical alternating current and emits an oscillating electromagnetic field, but also an electronic subassembly that receives a supply current and converts it into electrical alternating current for supply to the magnetic subassembly. The power conversion device further includes heat dissipation means for dissipating the heat generated by the electronic subassembly and / or the magnetic subassembly during their respective power conversion operations.

[0003] A power conversion device, also called a wireless charging station or a ground pad module (GPM), can be used to supply energy to a wireless charging device, also called a car pad module (CPM). Such a CPM mainly receives an oscillating electromagnetic field, which is a magnetic field, from the GPM, converts the oscillating electromagnetic field into alternating current, further converts the alternating current (typically rectifies the alternating current), and generates a charging current (typically direct current) used for charging the vehicle's driving battery from the alternating current.

[0004] Electric vehicle batteries can be charged with alternating current (AC) or direct current (DC). A typical AC charging device can supply up to 22 kW of charging power. AC charging systems can be subdivided into cable-connected and cableless charging systems, with cableless charging systems primarily designed as inductive charging systems (ICS). An ICS generally consists of two separate modules, often called a ground pad module (GPM) and a car pad module (CPM). The GPM is mounted on the outside of the electric vehicle, while the CPM is mounted inside the electric vehicle, generally on the underside of the vehicle. Electromagnetic interaction between the GPM and CPM enables energy transfer from the GPM to the CPM, which is then used to charge the electric vehicle's battery. Cableless charging systems are generally more user-friendly because they generally do not require manual intervention other than placing the vehicle on the GPM to initiate the battery charging process. [Overview of the project]

[0005] A GPM typically comprises a magnetic subassembly and an electronic subassembly. The magnetic subassembly includes coils and ferrite elements that generate heat during GPM operation and require cooling. The electronic subassembly similarly requires cooling. The magnetic and electronic subassemblies can be housed in a common enclosure or in separate, functionally coupled modules. An air cooler with one or more centrifugal fans can be provided to cool the electronic assembly and / or the magnetic subassembly. Centrifugal fans can cause unpleasant noise emission.

[0006] The object of the present invention is therefore to provide a power conversion device of the type mentioned at the beginning, equipped with a centrifugal fan that reduces noise emission.

[0007] This objective is achieved by a power converter having the features of claim 1. The power converter functions to convert the power of the supplied current into the electromagnetic force of the oscillating electromagnetic field. A magnetic subassembly for receiving or transmitting alternating current and / or emitting an oscillating electromagnetic field, An electronic subassembly for receiving the supply current and converting it into alternating current for supplying the magnetic subassembly, The electronic subassembly and / or magnetic subassembly have heat dissipation means for dissipating the heat generated during their respective power conversion operations. It is equipped with.

[0008] In this specification, it is a fact that the heat dissipation means comprises at least one centrifugal fan arranged to transport air for cooling a magnetic subassembly and / or an electronic subassembly, the centrifugal fan having a fan wheel transporting air through at least one cutoff edge to at least one exhaust port passage, the cutoff edge having an angle, hereafter referred to as the effective edge angle, in the region close to the fan wheel with respect to the rotation axis of the centrifugal fan, in particular an effective edge angle of at least 20°.

[0009] In the case of centrifugal fans, the cutoff edge is the part of the fan enclosure's exhaust port closest to the tip of the fan wheel blades. While conventional separation points have a straight edge parallel to the blade tip, the edge of a V-shaped channel (V-notch) extends diagonally relative to the blade tip.

[0010] The edge angle can be measured, for example, in a projection of the cutoff edge along the direction of a straight line connecting the cutoff edge and the axis of rotation. The projection can be created on a plane that includes the axis of rotation and is placed perpendicular to the connected line. If the cutoff edge does not extend linearly in the area of ​​the cutoff edge in this projection, a correction line (regression line) is drawn passing through this projection. The angle of this correction line with respect to the axis of rotation is considered to be the mean edge angle in this area.

[0011] The effective edge angle is so named because each region of the cutoff edge lies in the vicinity of the fan wheel, and this has a significant impact on flow and noise generation. The effective edge angle can be defined as the average edge angle in the vicinity. The effective edge angle can also be designed as the average edge angle in the region up to half the height of the fan wheel.

[0012] As explained above, by angling the cutoff edge, the cutoff edge moves away from the fan wheel in the near-field and connects to the far-field. The greater the distance from the cutoff edge to the fan wheel, the less vortex and noise is emitted, but this comes at the expense of transport performance. A compromise between these conflicting requirements can be found by selecting the effective edge angle in the near-field.

[0013] Magnetic and electronic subassemblies are functionally connected to each other by exchanging electrical energy. The magnetic and electronic subassemblies can be housed in a common housing or module, or in separate housing modules that are electrically connected to each other.

[0014] In the embodiment, the power converter is provided in combination with a wireless charging device, the power converter is designed as a wireless charging station, and the power converter and charging device together form an electromagnetic induction power transmission system for charging or discharging a vehicle battery in particular.

[0015] In the embodiment, the average effective edge angle is between 30° and 60°, particularly between 40° and 50°, and especially 45°.

[0016] In this embodiment, the cutoff edge begins in the proximity region, where it extends first by an average first edge angle, and then extends by an average second edge angle, where the second edge angle is smaller than the first edge angle.

[0017] This effect results in a longer distance from the cutoff edge to the fan wheel in the adjacent region compared to the case where the path of the cutoff edge is in the same direction as the path in the remaining region. Consequently, the airflow carried in the adjacent region has relatively little deflection and a larger flow cross-sectional area. As a result, the flow separates better from the cutoff edge and vortices are reduced. Consequently, sound wave emission is significantly reduced. In addition to the aforementioned compromise between emission and transport performance, assuming equivalent transport performance, this shape of the cutoff edge allows for emission reduction.

[0018] The characterization of the cutoff edge path can be performed using the same projection as described above for the edge angle. Therefore, when describing the cutoff angle at a specific location on the cutoff edge, or the average angle over a specific area of ​​the cutoff edge, this refers to the angle in this projection. The descriptions remain valid even if the projection direction and projection plane are slightly rotated around the axis of rotation.

[0019] In the embodiment, the cutoff edge has a path that begins in the near region and extends first with a first edge angle in the near region, and then with a smaller edge angle in the far region. In particular, the cutoff edge extends by continuously transitioning between two regions having different edge angles. This continuous transition is advantageous with respect to vortex generation.

[0020] In an embodiment, the cutoff edge starts in the proximity region and has an S-shaped path that first extends at a first edge angle in the proximity region, then at a smaller edge angle, and then again at a larger edge angle in the remote region. The cutoff edge, in particular any of them, extends continuously transitioning between two regions having different edge angles.

[0021] In an embodiment, the cutoff edge starts in the proximity region and has a U-shaped path that extends at a first edge angle first in the proximity region, then at a smaller edge angle, and then at at least one edge angle of opposite sign in the remote region. The cutoff edge, in particular any of them, extends continuously transitioning between two regions having different edge angles.

[0022] In an embodiment, with respect to the extension line of the fan wheel, hereinafter referred to as the height of the fan wheel, considered in the direction of the axis of rotation, the proximity region extends from 10% to 60%, particularly from 20% to 40% of the height of the fan wheel.

[0023] The subject matter of the present invention is explained in more detail by way of examples of preferred embodiments shown in the accompanying drawings. All the drawings are shown schematically.

Brief Description of the Drawings

[0024] [Figure 1] It is a diagram showing a garage where a vehicle is parked. [Figure 2] It is a diagram showing the arrangement of a cableless charging station and a cableless charging device. [Figure 3] It is a diagram showing the centrifugal fan of the cableless charging station. [Figure 4] It is a perspective view of the fan wheel with respect to the cutoff edge. [Figure 5] It is a perspective view of the fan wheel with respect to the cutoff edge. [Figure 6] It is a side view of the cutoff edge. [Figure 7] It is a diagram showing various paths of the cutoff edge. [Figure 8] This figure shows various paths along the cutoff edge. [Figure 9] This figure shows various paths along the cutoff edge. [Modes for carrying out the invention]

[0025] The reference numbers used in the drawings and their meanings are listed in the reference number list. Generally, the same or functionally equivalent parts are assigned the same reference number in the drawings.

[0026] The plan view of Figure 1 shows a garage 1 in which a vehicle 2 is parked above a cableless charging station 3 located outside the vehicle 2 and equipped with an emitter that transmits vibrational magnetic fields. The vehicle 2 is shown transparent so that the charging station 3 can be seen in the figure. Such a charging solution is fully adaptable and the driver does not need to connect or disconnect charging cables.

[0027] Figure 2 is a magnified view of the details from Figure 1, showing not only the cableless charging station 3, i.e., the GPM (Ground Pad Module), but also a cableless charging device 4, i.e., the CPM (Car Pad Module), positioned above the charging station for charging the vehicle 2's drive battery, typically a high-voltage battery (HV). The aforementioned charging device 4 is mounted on the vehicle 2. The magnetic subassembly 31 and the electronic subassembly 32 are schematically depicted as components inside the GPM 3. The magnetic subassembly comprises a coil and ferrite elements that generate heat during the operation of the GPM 3 and require cooling. The electronic subassembly 32 similarly requires cooling. The magnetic and electrical subassemblies can be housed in a common housing, as shown here. Alternatively, the magnetic and electrical subassemblies can be housed in separate housings or modules, functionally coupled to each other for electrical energy exchange.

[0028] Figure 3 schematically shows a centrifugal fan 5 located in the GPM3 for air cooling of the GPM3's subassemblies, particularly the magnetic subassembly 31 and / or the electronic subassembly 32. Cooling air is directed not only over the ferrite and stranded wires of the magnetic subassembly 31 but also over the electronic subassembly 32 for air cooling.

[0029] The centrifugal fan 5 comprises a fan wheel 51 with a rotating axis 53 and blades 52. The fan wheel 51 transports cooling air from the intake area 54 to one or more exhaust passages 56. In each exhaust passage 56, the airflow at the cutoff edge 55 is directed away from the fan wheel 51 into the exhaust passage 56. Here, airflow vortices are generated at the cutoff edge 55, and these vortices cause noise emission, degrading the efficiency of the centrifugal fan 5.

[0030] Figures 4 and 5 show perspective views of only the fan wheel 51 relative to the cutoff edge 55. Figure 6 shows a side view of only the cutoff edge 55. The figures show two inclined and slightly curved lines. The left line of these lines indicates the outermost edge of the cutoff edge 55 visible in the figure, and the right line of these lines indicates the transition between the arc-shaped region of the cutoff edge 55 and the planar region of the wall of the exhaust port passage 56 connected to the arc-shaped region.

[0031] The cutoff edge 55 is inclined with respect to the axis of rotation 53 throughout its entirety. The average path of the cutoff edge 55 is shown by a dashed line. The angle of the path of the cutoff edge with respect to the axis of rotation 53 is called the average angle or edge angle k. Considering only the individual regions of the cutoff edge 55, these regions can have a variety of average edge angles.

[0032] The cutoff edge 55 includes a first edge region 64 that begins at the lower part of the cutoff edge 55 in Figure 6 and extends downward from the lower edge of the fan wheel 51 in the height region. The cutoff edge 55 then includes a proximity region 63 that first approaches the fan wheel 51 and then moves away from the fan wheel 51 toward a distance region 62. A second edge region 61 that extends upward from the upper edge of the fan wheel 51 in the height region follows the distance region 62. Hereafter, when "height" is referred to, it means the height in Figure 6, i.e., the height starting from the lower edge of the fan wheel 51. The intake region 54 is below the fan wheel 51. The incoming air then enters the fan wheel 51 from below.

[0033] The proximity region 63 has a relatively large influence on the effects of airflow and the noise and transport force associated with the airflow, and can therefore be called the effective region, and the average edge angle of the proximity region 63 can also be called the effective edge angle. Depending on the embodiment, the proximity region can extend to 10% to 60% of the height of the fan wheel 51, and in particular to 20% to 40% of the height of the fan wheel 51.

[0034] The cutoff edge 55 has a wedge-shaped cross-section, as is readily apparent in Figure 3 when projected onto a plane perpendicular to the axis of rotation 53. As the height of the cutoff edge 55 increases, the cutoff edge moves away from the fan wheel 51 on the one hand, and its curvature (considered in the projection mentioned) gradually decreases on the other hand. This is shown by the dashed height lines in Figure 3. The solid lines correspond to the paths of the cutoff edge 55 at the height of the first edge region 64, and the dashed lines correspond to the paths assuming increasing height. As a result, the airflow path along the cutoff edge 55 becomes longer as the height increases. This reduces air deflection. This reduction in deflection, coupled with the increased distance from the fan wheel 51, leads to an air vortex with less of the adverse effects mentioned. Thus, the separation of airflow into the exhaust port passage 56 is improved. This is done at the expense of transport performance. By selecting the effective edge angle according to predetermined design standards, a compromise between noise generation and transport performance can be chosen.

[0035] By giving the path of the cutoff edge 55 a special shape, the overall optimal conditions can be improved at this compromise point. For this reason, the cutoff edge 55 shown in Figure 6 has an S-shaped path that starts in the proximity region 63, extends first with a first edge angle in the proximity region 63, then with a smaller edge angle, and then again with a larger edge angle in the distance region 62.

[0036] The crucial point here is that the path has, first, a larger edge angle, and then a smaller edge angle. This allows for improved transport performance, assuming equivalent noise generation, compared to, for example, a straight cutoff edge 55. Alternatively, assuming equivalent transport performance, less noise generation can be achieved. The optimal path conditions can be determined by numerical simulation.

[0037] The path along the entire height of the cutoff edge 55 can be designed in a different way, as shown in Figures 7 to 9. Each figure schematically shows a straight section corresponding to the average edge angle of each section. The transitions between sections are typically smooth or rounded, i.e., they transition continuously as shown in Figure 6.

[0038] In Figure 7, the cutoff edge 55 extends with a first edge angle throughout the adjacent region 63, followed by a smaller edge angle in the distant region 62. In Figure 8, the cutoff edge 55 has an S-shaped path, as already described in detail above. In Figure 9, the cutoff edge 55 has a U-shaped path, starting with a first edge angle in the adjacent region 63, followed by smaller edge angles, followed by at least one edge angle of the opposite sign in the distant region 62.

[0039] In a further embodiment, the cutoff edge 55 in the distant region extends at least substantially in a mirror image with respect to the adjacent region 63. [Explanation of Symbols]

[0040] 1 Garage 2 vehicles 3 GPM 31 Magnetic subassembly 32 Electronic subassemblies 4 CPM 5. Centrifugal fan 51 Fan Wheel 52 feathers 53 Rotation axis 54 Intake area 55 Cut-off edge 56 Exhaust port flow path 61 First marginal region 62 Remote Areas 63 Proximity 64 Second marginal region

Claims

1. A power conversion device (3) that converts the power of the supplied current into the electromagnetic force of an oscillating electromagnetic field, A magnetic subassembly (31) for receiving or transmitting alternating current and / or emitting an oscillating electromagnetic field, An electronic subassembly (32) for receiving the supply current and converting the supply current into alternating current for supplying the magnetic subassembly, The electronic subassembly and / or the magnetic subassembly are provided with heat dissipation means for dissipating heat generated during their respective power conversion operations, Equipped with, The heat dissipation means includes at least one centrifugal fan (5) arranged to transport air for cooling the magnetic subassembly and / or the electronic subassembly, The centrifugal fan (5) equipped with a fan wheel (51) transports the air through at least one cutoff edge (55) to at least one exhaust port passage (56), wherein the cutoff edge (55) in the region (63) adjacent to the fan wheel (51) forms a certain angle with respect to the rotation axis (53) of the centrifugal fan (5), called the effective edge angle (k), and the effective edge angle (k) is at least 20°. Power converter (3).

2. The power converter (3) is designed to be used in combination with the wireless charging device (4) as a wireless charging station. The power converter (3) according to claim 1, wherein the power converter (3) and the wireless charging device (4) are integrated to form an electromagnetic induction power transmission system for charging or discharging the battery of a vehicle (2).

3. The power conversion device (3) according to claim 1 or 2, wherein the average of the effective edge angle (k) is between 30° and 60°, particularly between 40° and 50°, and particularly 45°.

4. The power converter (3) according to any one of claims 1 to 3, wherein the cutoff edge (55) begins in the proximity region (63), extends in the proximity region (63) by an average first edge angle, and then extends by an average second edge angle, the second edge angle being smaller than the first edge angle.

5. The power converter (3) according to claim 4, wherein the cutoff edge (55) has a path that starts in the proximity region (63), extends in the proximity region (63) with the first edge angle, and then extends in the distance region (62) with a smaller edge angle, and the path continuously transitions between two regions having different edge angles.

6. The power converter (3) according to claim 4, wherein the cutoff edge (55) has an S-shaped path that transitions continuously between two regions having different edge angles, starting in the proximity region (63), extending in the proximity region (63) at the first edge angle, then extending at a smaller edge angle, and then extending again in the distance region (62) at a larger edge angle.

7. The power converter (3) according to claim 4, wherein the cutoff edge (55) has a path that starts in the proximity region (63), extends in the proximity region (63) with the first edge angle, then extends with a smaller edge angle, and then extends in the distance region (62) with at least one edge angle of opposite sign, a U-shaped path that continuously transitions between two regions having different edge angles.

8. With respect to the extension of the fan wheel (51) in the direction of the rotation axis (53) (hereinafter referred to as "the height of the fan wheel (51)"), the proximity region (63) extends to 10% to 60% of the height of the fan wheel (51), particularly to 20% to 40% of the height of the fan wheel (51), as described in any one of claims 4 to 6, the power conversion device (3) according to claim 4 to 6.

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