Power Conversion Device

Abstract

To provide a power conversion device which can achieve both a low loss and reduction in a cost without largely changing its structure.SOLUTION: A power conversion device 1 mounted on a vehicle includes: a lamination unit 12 where coolers 11 are laminated; and power cards 13 which are arranged between the respective coolers 11 of the lamination unit 12 and store a semiconductor element. In the lamination unit 12, dummy cards are arranged instead of the power cards between the coolers on an inlet side of the coolers 11. An inverter circuit 2 of the power conversion device includes a plurality of switching elements 21, a plurality of diodes 22, a reactor 23, a filter capacitor 24, and a battery 25, and the two switching elements 21 and the two diodes 22 are constituted as the power cards 13 composed of a package sealed with a resin material.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a power conversion device. [Background technology]

[0002] Patent Document 1 discloses a power conversion device including a stacked unit in which coolers are stacked, and a power card arranged between each cooler of the stacked unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-204688 Summary of the Invention [Problem to be solved by the invention]

[0004] There was a need for technology that could achieve both low loss and cost reduction without significantly changing the structure of the power conversion device.

[0005] The present disclosure has been made in view of the above, and aims to provide a power conversion device that can achieve both low loss and cost reduction without significantly changing the structure. [Means for solving the problem]

[0006] The power conversion device according to the present disclosure is a power conversion device mounted on a vehicle, and comprises a stacked unit in which coolers are stacked, and a power card arranged between each cooler of the stacked unit and housing a semiconductor element, and a dummy card is arranged between the coolers on the inlet side of the coolers in the stacked unit. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to achieve both low loss and cost reduction without making major changes to the structure. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of a power conversion device according to an embodiment. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of an inverter circuit included in the power conversion device according to the embodiment. [Figure 3] FIG. 3 is a diagram showing the correspondence between elements of an inverter circuit, power cards, and dummy cards in a power conversion device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A power conversion device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially the same.

[0010] The power conversion device (Power Control Unit: PCU) according to this embodiment is mounted on, for example, a vehicle equipped with a motor as a power source, for driving the motor. Examples of vehicles that may be equipped with the power conversion device include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell electric vehicles (FCEVs), and battery electric vehicles (BEVs).

[0011] 1, the power conversion device 1 includes a stacked unit 12 in which a plurality of coolers 11 are stacked, power cards 13 arranged between the coolers 11 of the stacked unit 12, and a dummy card (see FIG. 3). Although not shown in the figure, the power conversion device 1 also includes a case for accommodating the stacked unit 12, a battery connector, a motor connector, and the like.

[0012] The power conversion device 1 also includes an inverter circuit 2 as shown in Fig. 2. The inverter circuit 2 includes a plurality of switching elements 21, a plurality of diodes 22, a reactor 23, a filter capacitor 24, and a battery 25. Of the components shown in the figure, the semiconductor elements indicated by part A (hereinafter referred to as "boost elements") form a boost converter.

[0013] In the inverter circuit 2, two switching elements 21 are connected in series, and two of the two series-connected switching elements 21 are connected in parallel. Also, a diode 22 is connected in anti-parallel to each switching element 21.

[0014] One end of the reactor 23 is connected to a terminal on the battery 25 side. The other end of the reactor 23 is connected to the midpoint of the series circuit of the two switching elements 21. The filter capacitor 24 is connected between both ends of the terminal on the battery 25 side.

[0015] The power card 13 shown in Fig. 1 houses a semiconductor element. Specifically, the power card 13 is configured as a package in which two switching elements 21 and two diodes 22 shown in Fig. 2 are sealed with a resin material. For example, in Fig. 3, the first power card 13 from the inlet side (upstream side) of the cooler 11 houses a boost element shown in part B. Also, in the same figure, the second power card 13 from the inlet side of the cooler 11 houses a boost element shown in part C.

[0016] Here, as shown in Figure 2, the main reason for connecting two boost elements in parallel is to increase the amount of power. In recent years, with the electrification of vehicles, many converters and inverters use boost elements connected in parallel.

[0017] For example, if a two-parallel connection boost element is changed to a single connection, it is generally believed that losses will worsen. However, when actually comparing two-parallel connection with a single connection, ON losses are "two-parallel connection > single connection" and SW losses are "two-parallel connection < single connection," and losses tend to be larger in the two-parallel connection in the low current range where SW losses are dominant. Therefore, in the power conversion device 1 according to this embodiment, assuming a vehicle with a light vehicle load, the boost element is changed to a single connection.

[0018] 3, in the power conversion device according to this embodiment, a dummy card is placed between the coolers 11 on the inlet side of the coolers 11 instead of the power cards 13. That is, the first power card 13 from the inlet side of the coolers 11 is changed to a dummy card.

[0019] Here, the dummy card is a card that has the same shape as the power card 13 and is made of a resin material. Furthermore, this dummy card does not house any semiconductor elements. In this way, in the power conversion device according to this embodiment, the first power card 13 is removed from the inlet side of the cooler 11, thereby eliminating the boost element shown in part B of FIG. 3. As a result, the boost element that constitutes the boost converter becomes single-connected.

[0020] 3, there is a slight difference in the flow of cooling water between the inlet and outlet sides of the cooler 11, resulting in a decrease in cooling performance on the outlet side compared to the inlet side. Therefore, by replacing the first power card 13 from the inlet side of the cooler 11 of the two power cards 13 that make up the boost element with a dummy card, the decrease in cooling performance can be suppressed.

[0021] In this way, by replacing some of the multiple power cards 13 with dummy cards and changing the boost element to a single connection, it is possible to reduce loss in areas where the vehicle load is low. As a result, it is possible to improve the fuel efficiency of the vehicle. For example, in a "2.5L, hybrid vehicle, 381D, WLTP (fuel economy test method)" vehicle, the power conversion device alone can reduce power consumption by 2.8 W, achieving a 0.33% improvement in fuel efficiency for the entire vehicle.

[0022] Also, significant cost reductions can be achieved by reducing the number of boost elements, which account for a large proportion of the cost of the components that make up the power conversion device 1. Furthermore, by using a dummy card with the same shape as the power card 13, the external shape remains the same as when two boost elements are connected in parallel, which makes it possible to improve fuel efficiency and reduce costs without requiring major development efforts.

[0023] The power conversion device according to the present embodiment described above can achieve both low loss and cost reduction without making major structural changes. In other words, even when the number of boost elements is changed depending on the magnitude of the vehicle load, it is possible to change the number of boost elements inexpensively without having to change the shape of the power conversion device 1 itself. Furthermore, by placing a dummy card near the inlet of the cooler 11, the cooling performance of the entire power card 13 can be improved.

[0024] Further advantages and modifications will readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0025] 1 Power conversion device 11 Cooler 12 Stacking Unit 13 Power Card 2. Inverter circuit 21 Switching element 22 Diode 23 Reactor 24 filter capacitor

Claims

[Claim 1] A power conversion device mounted on a vehicle, a stacked unit in which coolers are stacked; a power card disposed between the coolers of the stacked unit and housing a semiconductor element; Equipped with In the stacked unit, a dummy card is disposed between the coolers on the inlet side of the coolers, the dummy card is made of a resin material, the semiconductor element is a boost element that constitutes a boost converter, the boost element is single-connected between the battery and the motor; Power conversion device.

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