Power conversion arrangement with cooling fan

Abstract

A power conversion arrangement (3) is used as a wireless charging station ("ground-pad module") for supplying energy to a wireless charging device of an electric vehicle. It has a magnetic assembly (31) and an electronic assembly (32), as well as heat dissipation means with a radial blower (5) for cooling the magnetic and / or electronic assembly. The radial blower (5) uses a blower wheel (51) to convey air into at least one outlet channel (56) past a cutoff edge (55). In a region (63) close to the blower wheel (51), the cutoff edge (55) is angled at an effective edge angle (k), in particular an effective edge angle (k) of at least twenty degrees, to a rotational axis (53) of the radial blower (5).

Description

[0001] POWER CONVERSION ARRANGEMENT WITH COOLING FAN

[0002] The present invention relates to a power conversion arrangement for converting the electrical power of an electrical supply current into electromagnetic power of an oscillating electromagnetic field. The power conversion arrangement comprises a magnetic assembly for receiving an alternating electrical current and radiating an oscillating electromagnetic field, as well as an electronic assembly for receiving the electrical supply current and converting it into an alternating electrical current for supplying the magnetic assembly. The power conversion arrangement further comprises heat dissipation means for dissipating heat generated by the electronic assembly and / or the magnetic assembly during their respective power conversion operations.

[0003] The power conversion assembly, also known as a wireless charging station or ground pad module (GPM), can be used to power a wireless charger, also known as a car pad module (CPM). Such a CPM can receive the oscillating electromagnetic, predominantly magnetic, field from the GPM, convert it into an alternating current, further convert it (typically rectify it), and then generate a charging current (typically direct current) used to charge a vehicle's traction battery. Electric vehicle batteries can be charged with alternating current (AC) or direct current (DC). Typical AC chargers can provide a charging power of up to 22 kW. AC charging systems can be divided into wired charging systems and wireless charging systems, with wireless charging systems primarily being implemented as inductive charging systems (ICS).An ICS typically consists of two separate modules, often referred to as a ground pad module (GPM) and a car pad module (CPM). The GPM is installed outside the EV, while the CPM is mounted inside the EV, typically on the underside of the vehicle. The electromagnetic interaction between the GPM and the CPM enables power transfer from the GPM to the CPM, and the CPM is, in turn, used to charge an EV battery. Wireless charging systems are often more convenient for the user, as no manual intervention is usually required to initiate battery charging, other than parking the vehicle over the GPM.

[0004] A GPM typically comprises a magnetic assembly and an electronic assembly. The magnetic assembly includes a coil and ferrite elements that heat up during operation of the GPM and must be cooled. The electronic assembly also requires cooling. The magnetic and electrical assemblies can be arranged in a common housing or in separate, functionally coupled modules. Air cooling with one or more radial fans can be arranged to cool the electronic assembly and / or the magnetic assembly. Radial fans cause disruptive noise emissions.

[0005] It is therefore an object of the invention to provide a power conversion arrangement of the type mentioned above, with a radial fan with reduced noise emissions.

[0006] This object is achieved by a power conversion arrangement having the features of patent claim 1. The power conversion arrangement serves to convert the electrical power of an electrical supply current into electromagnetic power of an oscillating electromagnetic field. It comprises:

[0007] • a magnetic assembly for receiving or emitting an alternating electric current and for radiating an oscillating electromagnetic field, and

[0008] • an electronic assembly for receiving the electrical supply current and converting it into an alternating electrical current to supply the magnetic assembly,

[0009] • Heat dissipation means for dissipating heat generated by the electronic assembly and / or the magnetic assembly during their respective power conversion operations.

[0010] In this case, the heat dissipation means comprise at least one radial fan which is arranged to convey air for cooling the magnetic and / or the electronic assembly, wherein the radial fan conveys the air into at least one outlet channel past at least one cutoff edge with a fan wheel, wherein the cutoff edge is angled with respect to a rotational axis of the radial fan in a region close to the fan wheel by an angle, hereinafter referred to as the effective edge angle, in particular by an effective edge angle of at least twenty degrees.

[0011] In a centrifugal fan, the cutoff edge is the part of the fan casing at the outlet closest to the impeller blade tips. A conventional cutoff has a straight edge parallel to the blade tips, while the edges of a V-notch are angled to the blade tips.

[0012] Edge angles can be measured, for example, in a projection of the cutoff edge along the direction of a connecting line between the cutoff edge and the rotation axis. The projection can be made onto a plane containing the rotation axis and normal to the connecting line. If the cutoff edge is not straight in a section of this projection, a regression line is drawn through this projection. The angle of this regression line relative to the rotation axis is considered the mean edge angle in this section.

[0013] The effective edge angle is named this way because the corresponding section of the cutoff edge is located in close proximity to the fan impeller and thus has a strong influence on the flow and noise generation. The effective edge angle can be defined as the average edge angle in the close proximity. It can also be defined as the average edge angle in a range up to half the height of the fan impeller.

[0014] By angled as described above, the cutoff edge directs the air flow away from the fan impeller in the near area. The further the cutoff edge is from the fan impeller, the lower the turbulence and noise emissions, but at the expense of airflow performance. By selecting the effective edge angle in the near area, a balance can be created between these conflicting requirements.

[0015] The magnetic and electronic components are functionally connected by exchanging electrical energy. They can be arranged in a common housing or module, or in separate housings or modules that are electrically connected.

[0016] In embodiments, the power conversion assembly is combined with a wireless charger, wherein the power conversion assembly is configured as a wireless charging station, and the power conversion assembly and the charger together form an inductive power transmission system, in particular for charging or discharging a vehicle battery. In embodiments, the average effective edge angle is between 30° and 60°, in particular between 40° and 50°, in particular 45°.

[0017] In embodiments, the cutoff edge, starting at the near area, initially runs in the near area on average with a first edge angle, and then runs on average with a second edge angle, wherein the second edge angle is smaller than the first edge angle.

[0018] The effect of this is that in the near zone, the distance between the cutoff edge and the fan impeller is greater than would be the case if the cutoff edge ran in the same direction as in the rest of the zone. The conveyed airflow is thus subject to comparatively less deflection in the near zone and has a larger flow cross-section. As a result, the flow separates more effectively from the cutoff edge, with less turbulence. This results in a noticeable reduction in acoustic emissions. In addition to the balance between emissions and airflow performance described above, this cutoff edge shape makes it possible to reduce emissions while maintaining the same airflow performance.

[0019] The cutoff edge's shape can be characterized in the same projection as described above for the edge angle. Therefore, when referring to the angle of the cutoff edge at a specific location or as the average angle over a specific section of the cutoff edge, this refers to angles in this projection. These statements remain valid even if the projection direction and the projection plane are slightly rotated around the rotation axis.

[0020] In embodiments, the cutoff edge has the following profile: starting in the near area, it initially runs with the first edge angle in the near area and then with a smaller edge angle in the far area. In particular, it runs with a continuous transition between two areas with different edge angles. This continuous transition is advantageous with regard to turbulence.

[0021] In some embodiments, the cutoff edge has an S-shaped profile: starting in the near area, it initially runs with the first edge angle in the near area, followed by a smaller edge angle, and then in the far area with a larger edge angle again. In particular, it runs with a continuous transition between two areas with different edge angles.

[0022] In embodiments, the cutoff edge has a U-shaped profile: starting in the near area, it initially runs with the first edge angle in the near area and then with a smaller edge angle, and then in the far area with at least one edge angle with the opposite sign. In particular, it runs with a continuous transition between two areas with different edge angles.

[0023] In embodiments, with respect to an extension of the fan wheel in the direction of the rotation axis, hereinafter referred to as the height of the fan wheel, the near area covers between 10% and 60% of the height of the fan wheel, in particular between 20% and 40% of the height of the fan wheel.

[0024] The subject matter of the invention is explained in more detail below with reference to preferred embodiments, which are illustrated in the accompanying drawings. They show schematically:

[0025] Figure 1 shows a garage with a vehicle parked in it;

[0026] Figure 2 shows an arrangement of a wireless charging station and a wireless charger; Figure 3 shows a radial fan of the wireless charging station;

[0027] Figures 4-5 show perspective views of the fan wheel in relation to a cutoff edge;

[0028] Figure 6 shows a side view of the cutoff edge; and Figures 7 - 9 show different cutoff edge profiles.

[0029] The reference symbols used in the drawings and their meanings are summarized in the list of reference symbols. In general, identical or functionally equivalent parts are provided with the same reference symbols in the figures.

[0030] Figure 1 shows a top view of a garage 1 in which a vehicle 2 is parked above a wireless charging station 3 located outside the vehicle 2 and equipped with a transmitter for transmitting an oscillating magnetic field. The charging station 3 is visible in the figure because the vehicle 2 is shown transparently. Such a charging solution is very convenient and saves the driver from having to plug and unplug a charging cable.

[0031] Figure 2 is an enlargement of a section of Figure 1 and shows the wireless charging station 3 or GPM (Ground Pad Module) and a wireless charger 4 or CPM (Car Pad Module) arranged above the charging station 3 for charging a traction battery, typically a high-voltage (HV) battery, of the vehicle 2. The charger 4 is installed in the vehicle 2. A magnetic assembly 31 and an electronic assembly 32 are schematically shown as parts within the GPM 3. The magnetic assembly has a coil and ferrite elements that heat up during operation of the GPM 3 and must be cooled. The electronic assembly 32 must also be cooled. The magnetic and electrical assemblies can be arranged in a common housing, as shown here. Alternatively, they can be arranged in separate housings or modules that are functionally coupled to exchange electrical energy.Figure 3 schematically shows a radial fan 5 arranged in the GPM 3 for air cooling of components of the GPM 3, in particular the magnetic assembly 31 and / or the electronic assembly 32. For this purpose, cooling air is directed over the ferrites and stranded wires of the magnetic assembly 31, as well as over the electronic assembly 323.

[0032] The radial fan 5 has a fan impeller 51 with a rotational axis 53 and blades 52. The fan impeller 51 conveys cooling air from an inlet area 54 to one or more outlet ducts 56. At each outlet duct 56, the air flow is directed away from the fan impeller 51 into the outlet duct 56 at a cutoff edge 55. This creates turbulence in the air flow at the cutoff edge 55, which leads to noise emissions and reduces the efficiency of the radial fan 5.

[0033] Figures 4 and 5 show perspective views of only the fan wheel 51 in relation to the cutoff edge 55. Figure 6 shows a side view of only the cutoff edge 55. The illustration shows two inclined and slightly curved lines. The left of these lines represents the outermost edge of the cutoff edge 55 visible in the view, while the right of these lines represents a transition between a curved area of ​​the cutoff edge 55 and an adjacent flat area of ​​the wall of the outlet channel 56.

[0034] The cutoff edge 55 as a whole is inclined with respect to the rotation axis 53. An averaged profile of the cutoff edge 55 is shown in dashed lines. The angle of this profile with respect to the rotation axis 53 is referred to as the mean angle or edge angle k. If only individual sections of the cutoff edge 55 are considered, these may have a different mean edge angle.

[0035] Starting in Figure 6 in the lower part of the cutoff edge 55, the cutoff edge

[0036] 55 has a first edge region 64, which runs at a height below a lower edge of the fan wheel 51. The cutoff edge 55 then has a first edge region 64, in which the cutoff edge 55 initially runs close to the fan wheel 51 and then moves away from it, toward a distant region 62. Adjacent to the distant region 62 is a second edge region 61, which runs at a height above an upper edge of the fan wheel 51. When "height" is mentioned below, this refers to the height as in Figure 6, i.e., starting from the lower edge of the fan wheel 51. The inlet region 54 is located below the fan wheel 51. The inflowing air thus enters the fan wheel 51 from below.

[0037] The near area 63 can also be referred to as the effective area, and the average edge angle in the near area 63 as the effective edge angle because it has a relatively large influence on the air flow and the associated effects on noise and air flow. Depending on the design, the near area can cover between 10% and 60% of the height of the fan impeller 51, in particular between 20% and 40% of the height of the fan impeller 51.

[0038] In a projection onto a plane normal to the rotation axis 53, the cutoff edge 55 has a wedge-shaped cross-section, as can be clearly seen in Figure 3. With increasing height of the cutoff edge 55, on the one hand, it moves further away from the fan wheel 51, and on the other hand, the curvature (viewed in the aforementioned projection) becomes increasingly smaller. This is illustrated in Figure 3 by dashed contour lines: The solid line corresponds to the course of the cutoff edge 55 at the height of the first edge region 64, the dashed lines the course with increasing height. As a result, with increasing height, the path of the air flow along the cutoff edge 55 becomes longer. This reduces the air deflection. This reduced deflection, in combination with the greater distance from the fan wheel 51, leads to a reduction in the air turbulence with the aforementioned disadvantageous effects. The separation of the air flow into the outlet channel 56 is thus improved.This occurs at the expense of conveying capacity. According to specified design criteria, a balance between noise generation and conveying capacity can be achieved by selecting the effective edge angle.

[0039] By a special shaping of the course of the cutoff edge 55, an overall optimum can be improved in this compensation: The cutoff edge 55 according to Figure 6 has an S-shaped course for this purpose: Starting at the near area 63, it initially runs in the near area 63 with a first edge angle and then a smaller edge angle, and then in the distant area 62 with a larger edge angle again.

[0040] The determining factor here is the progression of the initially larger and then smaller edge angles. This can, for example, result in better conveying performance with the same noise level compared to a straight cutoff edge 55. Alternatively, lower noise can be achieved with the same conveying performance. The optimum progression can be determined through numerical simulations.

[0041] The profile of the cutoff edge 55 over the entire height can be designed in various ways, as shown in Figures 7-9. These schematically show straight sections corresponding to the average edge angles of the respective sections. Typically, the transitions between the sections are smoothed or rounded, i.e., with continuous transitions as in Figure 6.

[0042] Figure 7: The cutoff edge 55 runs throughout the near region (63) with the first edge angle and then in the far region (62) with a smaller edge angle. Figure 8: The cutoff edge 55 has an S-shaped profile, as already described in detail above. Figure 9: The cutoff edge 55 has a U-shaped profile, beginning in the near region 63 with the first edge angle and then a smaller edge angle, and then in the far region (62) with at least one edge angle with the opposite sign. According to further embodiments, the cutoff edge 55 in the far region runs at least approximately mirror-inverted to the near region 63.

[0043] LIST OF REFERENCE SYMBOLS

[0044] 1 garage

[0045] 2 vehicles

[0046] 3 GPM

[0047] 31 magnetic assembly

[0048] 32 electronic assembly

[0049] 4 CPM

[0050] 5 radial fans

[0051] 51 Fan wheel

[0052] 52 shovels

[0053] 53 Rotation axis

[0054] 54 Entrance area

[0055] 55 cutoff edge

[0056] 56 exhaust duct

[0057] 61 first edge area

[0058] 62 remote area

[0059] 63 Close range

[0060] 64 second edge area

Claims

PATENT CLAIMS 1. Power conversion arrangement (3) for converting the electrical power of an electrical supply current into electromagnetic power of an oscillating electromagnetic field, comprising • a magnetic assembly (31) for receiving or emitting an alternating electric current and for radiating an oscillating electromagnetic field, and • an electronic assembly (32) for receiving the electrical supply current and converting it into an alternating electrical current for supplying the magnetic assembly, • Heat dissipation means for dissipating heat generated by the electronic assembly and / or the magnetic assembly during their respective power conversion operation, characterized in that the heat dissipation means comprise at least one radial fan (5) arranged to convey air for cooling the magnetic and / or the electronic assembly, wherein the radial fan (5) with a fan wheel (51) conveys the air into at least one outlet channel (56) past at least one cutoff edge (55), wherein the cutoff edge (55) is angled with respect to a rotation axis (53) of the radial fan (5) in a region close (63) to the fan wheel (51) by an angle, hereinafter referred to as the effective edge angle (k), in particular by an effective edge angle (k) of at least twenty degrees.

2. Power conversion arrangement (3) according to claim 1, in combination with a wireless charger (4), wherein the power conversion arrangement (3) is designed as a wireless charging station, and the power conversion arrangement (3) and the charger (4) together form an inductive power transmission system, in particular for charging or discharging a battery of a vehicle (2).

3. Power conversion arrangement (3) according to one of the preceding claims, wherein the mean effective edge angle (k) is between 30° and 60°, in particular between 40° and 50°, in particular 45°.

4. Power conversion arrangement (3) according to one of the preceding claims, wherein the cutoff edge (55), starting at the near region (63), initially runs in the near region (63) on average with a first edge angle and then runs on average with a second edge angle, wherein the second edge angle is smaller than the first edge angle.

5. Power conversion arrangement (3) according to claim 4, wherein the cutoff edge (55) has the following course: starting at the near area (63), first in the near area (63) with the first edge angle and then in the far area (62) with a smaller edge angle, and in particular with a continuous transition between two areas with different edge angles.

6. Power conversion arrangement (3) according to claim 4, wherein the cutoff edge (55) has an S-shaped course, starting at the near area (63), initially in the near area (63) with the first edge angle and then a smaller edge angle, and then in the distant area (62) with a larger edge angle again, and in particular with a continuous transition between two areas with different edge angles.

7. Power conversion arrangement (3) according to claim 4, wherein the cutoff edge (55) has a U-shaped course, starting at the near area (63), first in the near area (63) with the first edge angle and then a smaller edge angle, and then in the remote area (62) with at least one edge angle with an opposite sign, and in particular with a continuous transition between two regions with different edge angles.

8. The power conversion arrangement (3) according to any one of claims 4 to 6, wherein, with respect to an extension of the fan wheel (51) viewed in the direction of the rotation axis (53), hereinafter referred to as the height of the fan wheel (51), the near region (63) covers between 10% and 60% of the height of the fan wheel (51), in particular between 20% and 40% of the height of the fan wheel (51).

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