Power converter

Abstract

To provide a power conversion device which is simply formed by reducing the number of components, and in which a secondary-side semiconductor element can be cooled at low cost.SOLUTION: A power conversion device includes a plurality of semiconductor switching elements 4a to 4d for converting a DC voltage Vin to an AC voltage, an insulation transformer 2 that transmits the AC voltage from a primary side to a secondary side to output the AC voltage, and a rectification circuit 5 including a plurality of diodes 5a and 5b for rectifying the output. The plurality of semiconductor switching elements 4a to 4d and the plurality of diodes 5a and 5b are formed of modules sealed in the same package.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This application relates to a power conversion device.

Background Art

[0002] In an electrified vehicle such as an electric vehicle or a hybrid vehicle, a DC / DC converter is mounted to charge a low-voltage lead battery from a high-voltage lithium-ion battery. For the purpose of protection from high voltage, the high-voltage lithium-ion battery is insulated from the chassis or the low-voltage system, and generally, the DC / DC converter also requires insulation between the high-voltage input side and the low-voltage output side by an isolation transformer. At that time, the DC input voltage is switched by semiconductor elements or the like, converted into a signal such as an alternating current, input to the primary side of the isolation transformer, and the output of the secondary side of the isolation transformer is rectified by semiconductor elements or the like to obtain a DC output voltage.

[0003] The current flowing through the secondary side of the DC / DC converter of an electrified vehicle often requires a current of around several hundred amperes or more. In a normal glass epoxy substrate, since the copper thickness is thin, the temperature rise due to losses is large and it is difficult to apply. Therefore, for example, in Patent Document 1, a thick copper plate is used as wiring, discrete semiconductor elements for surface mounting are mounted on the copper plate, the copper plate is fixed to a cooler to suppress the temperature rise of the wiring due to a large current, and the discrete semiconductor elements are cooled.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Ensuring the cooling performance of discrete semiconductor elements mounted on a copper plate requires securely fixing the copper plate to the cooler. This necessitates not only the copper plate itself as wiring, but also screws or bushings to secure it, resulting in a high number of components and high manufacturing costs, not just material costs. Furthermore, the need to insert-molde the copper plate to ensure flatness and strength for fixing the input / output wiring of the discrete elements also contributed to increased costs. Moreover, depending on the output current, it may be necessary to arrange multiple discrete semiconductor elements, leading to a larger copper plate. Securing this larger plate requires an increased number of screws, further increasing the size of the copper plate, the area requiring cooling, and ultimately, the cost of the cooler. In particular, in circuit configurations where the copper plate cooling the discrete semiconductor elements requires insulation from the cooler, ensuring insulation reliability necessitates increasing the thickness of the grease or gap filler between the copper plate and the cooler, degrading cooling performance. This, combined with the increase in discrete semiconductor elements or the size of the copper plate, hinders cost reduction.

[0006] This application discloses technology to solve the above-mentioned problems, and aims to provide a power conversion device that can cool secondary semiconductor elements inexpensively with a simple configuration and a reduced number of components. [Means for solving the problem]

[0007] The power conversion device disclosed herein comprises a plurality of semiconductor switching elements that convert the DC voltage of a DC power supply into an AC voltage, an isolation transformer that transmits the AC voltage from the primary side to the secondary side and outputs it, and a rectifier circuit including a plurality of rectifier elements that rectifies the output, wherein the plurality of semiconductor switching elements and the plurality of rectifier elements are configured as modules sealed in the same package. The module has external terminals for connecting the plurality of switching elements, the plurality of rectifier elements, and an external circuit. The external terminals consist of a primary external terminal connecting the plurality of switching elements and the external circuit, and a secondary external terminal connecting the plurality of rectifier elements and the external circuit. Of the primary external terminals, the primary AC output terminal connected to the isolation transformer and the secondary AC input terminal connected to the isolation transformer are arranged on the same side of the module. It is characterized by being such. [Effects of the Invention]

[0008] The power conversion device disclosed in this application provides a power conversion device that can reduce the number of components and cool the secondary semiconductor elements inexpensively with a simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1] This is a circuit diagram of the power conversion device according to Embodiment 1. [Figure 2] This diagram shows the internal configuration of the power conversion device module according to Embodiment 1. [Figure 3] This figure shows the implementation structure of the power conversion device according to Embodiment 1. [Figure 4] This is a side view showing the implementation structure of the power conversion device according to Embodiment 1. [Figure 5] This is a circuit diagram of the power conversion device according to Embodiment 2. [Figure 6] This is a side view showing the implementation structure of the power conversion device according to Embodiment 2. [Figure 7] This is a plan view showing the implementation structure of the power conversion device according to Embodiment 2. [Figure 8] This is a side view showing another example of the implementation structure of the power converter according to Embodiment 2. [Modes for carrying out the invention]

[0010] Hereinafter, preferred embodiments of the power conversion device according to the present application will be described with reference to the drawings. In each drawing, identical or corresponding components and parts will be denoted by the same reference numerals.

[0011] Embodiment 1. Figure 1 is a circuit diagram of a power converter according to Embodiment 1. As shown in Figure 1, the power converter 100 converts the DC voltage Vin of the DC power supply 1 into a secondary DC voltage isolated by the transformer 2, and outputs the DC voltage Vout to a load 3 such as a battery.

[0012] The power converter 100 includes an isolated transformer 2, a single-phase inverter 4 which converts the DC voltage Vin of the DC power supply 1 to an AC voltage by connecting semiconductor switching elements 4a to 4d, each consisting of a MOSFET with a diode built into the source and drain, to the primary winding 2a of the transformer 2 in a full-bridge configuration, and a rectifier circuit 5 which has diodes 5a and 5b, which are semiconductor rectifier elements, connected to the secondary winding 2b of the transformer 2. A smoothing reactor 6 and a smoothing capacitor 7 are connected to the output of the rectifier circuit 5 for output smoothing, and a DC voltage Vout is output to the load 3. The transformer 2 has a center tap on the secondary side, and the center tap terminal is connected to GND, while the other secondary side terminals are connected to the anode terminals of diodes 5a and 5b, respectively. The cathode terminals of diodes 5a and 5b are connected to the smoothing reactor 6.

[0013] In the above, an example of a DC / DC converter with a center-tapped secondary side was shown as an example of the power conversion device 100, but the secondary side may also be a full-bridge configuration, and although a diode was shown as an example of a rectifier element, a MOSFET may also be used. Furthermore, although an example of a DC / DC converter with a full-bridge primary side was shown, any isolated converter with an isolation transformer, such as a forward type, flyback type, or LLC type, may be used. Note that the semiconductor switching elements 4a to 4d are not limited to MOSFETs, but may also be self-extinguishing semiconductor switching elements such as IGBTs (Insulated Gate Bipolar Transistors) with diodes connected in antiparallel. The same applies when the rectifier element is a MOSFET.

[0014] Next, the configuration of the module in which the primary semiconductor switching elements 4a to 4d and the secondary diodes 5a and 5b in this embodiment are enclosed in the same package will be explained using Figures 2(a) and 2(b). In Figures 2(a) and 2(b), the same reference numerals are used to indicate parts corresponding to those in Figure 1.

[0015] Fig. 2(a) is a top perspective view of module 8, and Fig. 2(b) is a cross-sectional perspective view from the front direction of Fig. 2(a). The cross-sectional structure of module 8 will be described with reference to Fig. 2. The semiconductor switching elements 4a to 4d are, for example, semiconductor chips having drain pads on the bottom surface and gate pads 40a to 40d and source pads 41a to 41d on the top surface respectively. The semiconductor switching elements 4a to 4d are mounted on lead frames 42a to 42d respectively. The diodes 5a, 5b are, for example, those having cathode pads on the bottom surface and anode pads on the top surface, and are mounted on the lead frame 43.

[0016] Reference numerals 44, 45a to 45d, 46a to 46d, 47a, 47b denote lead frames, and the lead frames 43, 44, 42a to 42d, 45a to 45d, 46a to 46d, 47a, 47b are insulated by the cooling plate 9 and the insulating member 10. The semiconductor switching elements 4a to 4d, the diodes 5a, 5b, the lead frames 43, 44, 42a to 42d, 45a to 45d, 46a to 46d, 47a, 47b, the cooling plate 9, and the insulating member 10 are molded by the resin 11 with the surface of the cooling plate 9 facing the bottom surface of the module 8 exposed. Also, the lead frames 42a to 42d, 43, 44, 45a to 45d, 46a to 46d, 47a, 47b are bent toward the top surface direction of the module 8 to form external terminals. In the cross-sectional perspective view of Fig. 2(b), connection wirings such as bonding are omitted.

[0017] Next, the top perspective view of module 8 shown in Fig. 2(a) will be described. The drain pad of the semiconductor switching element 4a is mounted on the lead frame 42a, and the lead frame 42a is connected to the positive electrode of the DC power supply 1 via, for example, a wiring pattern of a glass epoxy substrate. The source pad 41a of the semiconductor switching element 4a is connected to the lead frame 42b by wire bonding 48a, and the lead frame 42b is connected to the primary winding 2a of the transformer 2 via a wiring pattern of a glass epoxy substrate. The drain pad of the semiconductor switching element 4b is mounted on the lead frame 42b. The source pad 41b of the semiconductor switching element 4b is connected to the lead frame 44 by wire bonding 48b, and the lead frame 44 is connected to the negative electrode of the DC power supply 1 via a wiring pattern on a glass epoxy substrate or the like.

[0018] The drain pad of the semiconductor switching element 4c is mounted on the lead frame 42c, and the lead frame 42c is connected to the positive electrode of the DC power supply 1 via a wiring pattern on a glass epoxy substrate or the like. The source pad 41c of the semiconductor switching element 4c is connected to the lead frame 42d by wire bonding 48c, and the lead frame 42d is connected to the primary winding 2a of the transformer 2 via a wiring pattern on a glass epoxy substrate or the like. The drain pad of the semiconductor switching element 4d is mounted on the lead frame 42d. The source pad 41d of the semiconductor switching element 4d is connected to the lead frame 44 by wire bonding 48d.

[0019] Also, the respective gate pads 40a to 40d of the semiconductor switching elements 4a to 4d are connected to the lead frames 45a to 45d by wire bondings 49a to 49d, respectively. The lead frames 45a to 45d are connected to the gate circuit mounted on the glass epoxy substrate via a wiring pattern on the glass epoxy substrate. Further, the reference potential for gate driving of the semiconductor switching elements 4a to 4d is connected to the lead frames 46a to 46d by wire bondings 50a to 50d from the respective source pads 41a to 41d, respectively. The lead frames 46a to 46d are connected to the reference potential of the respective gate circuits mounted on the glass epoxy substrate via a wiring pattern on the glass epoxy substrate.

[0020] In the above example, the reference potential for gate driving of semiconductor switching elements 4a to 4d is shown to be connected from source pads 41a to 41d to lead frames 46a to 46d via wire bonding 50a to 50d. However, each semiconductor switching element 4a to 4d may also be provided with a gate driving pad separate from the source pads 41a to 41d, and these gate driving pads may be connected to lead frames 46a to 46d via wire bonding 50a to 50d.

[0021] Diode 5a is connected to lead frame 47a from anode pad 51a by wire bonding 52a, and lead frame 47a is connected to the secondary winding 2b of transformer 2 by, for example, soldering or welding. Diode 5b is connected to lead frame 47b from anode pad 51b by wire bonding 52b, and lead frame 47b is connected to the secondary winding 2b of transformer 2 by, for example, soldering or welding. The cathode pads of diodes 5a and 5b are mounted on a common lead frame 43, and lead frame 43 is connected to smoothing reactor 6.

[0022] Here, lead frames 42a-42d, 44, 45a-45d, and 46a-46d are primary-side external terminals, and lead frames 43, 47a, and 47b are secondary-side external terminals. Furthermore, lead frames 42a, 42c, and 44 are primary-side DC input terminals within the primary-side external terminals, and lead frames 42b and 42d are primary-side AC output terminals within the primary-side external terminals. In addition, lead frames 47a and 47b are secondary-side AC input terminals within the secondary-side external terminals, and lead frame 43 is a secondary-side DC output terminal.

[0023] The lead frames 42b and 42d may be connected on the glass epoxy substrate outside the module 8, or they may be connected inside the module by mounting a busbar that spans the lead frame 44. While examples show one wire bonding for the gate 49a-49d and three wire bonding for the drain, these are not the only numbers of wires used. Furthermore, a busbar may be used instead of wire bonding.

[0024] Next, the method for mounting the power converter of this embodiment into the housing will be explained using Figures 3(a) and 3(b). Figure 3(a) is a plan view showing the mounting structure of the power converter 100, and Figure 3(b) is a left side view showing the connection relationship of the external terminals. In Figures 3(a) and 3(b), the housing 12 is provided with an inlet 14 for a water channel 13 for cooling water, which is a refrigerant used to cool the main heat-generating components of the power converter 100, such as the module 8, transformer 2, and smoothing reactor 6, and an outlet 15 from the water channel 13. The housing 12 functions as a cooler with the cooling water flowing through the water channel 13, and the modules 8 are stacked in the direction normal to this cooler. The modules 8, transformer 2, and smoothing reactor 6 are mounted on the projection plane of the water channel 13. The substrate 16 is mounted so as to overlap the module 8. In this case, it may overlap at least a portion of the transformer 2 and smoothing reactor 6. In the module 8, parts common to Figure 2 are represented by the same reference numerals, and only the semiconductor switching elements 4a to 4d that constitute the inverter 4 and the diodes 5a and 5b that constitute the rectifier circuit 5 are shown, while the cooling plate 9, insulating member 10, and bonding wires are omitted.

[0025] In Figure 3(a), the inverter 4 is mounted in the left region of module 8, and the rectifier circuit 5 is mounted in the right region of module 8. Lead frames 42a, 42c, and 44, which serve as external terminals for connecting the inverter 4 to the DC power supply 1, are located on the side of module 8 facing the smoothing reactor 6. Together with lead frames 45a and 45c, which serve as gate terminals for semiconductor switching elements 4a and 4c respectively, they pass through through holes provided in the substrate 16 and are connected to the substrate 16 by solder or the like. Lead frames 42b and 42d, which serve as external terminals for connecting the inverter 4 to the transformer 2, are located on the side of module 8 facing the transformer 2. Together with lead frames 45b and 45d, which serve as gate terminals for semiconductor switching elements 4b and 4d respectively, they pass through through holes provided in the substrate 16 and are connected to the substrate 16 by solder or the like.

[0026] The lead frames 47a and 47b, which are external terminals connecting the rectifier circuit 5 to the transformer 2, are located on the side of the module 8 facing the transformer 2, and the lead frame 43, which is an external terminal connecting to the smoothing reactor 6, is located on the side of the module 8 facing the smoothing reactor 6. The terminals 53, 54, 55, and 56 of the transformer 2 are all located on the module 8 side, and the terminals 53 and 54 that connect to the inverter 4 are connected to the circuit board 16 by soldering or the like through through holes provided in the circuit board 16, and are connected to the lead frames 42b and 42d, which are external terminals of the module 8, via wiring 17 on the circuit board 16. In addition, the terminals 55 and 56 of the transformer 2 that connect to the rectifier circuit 5 are positioned to face the lead frames 47a and 47b, which are external terminals of the module 8, and are connected to the lead frames 47a and 47b, for example by welding.

[0027] The lead frame 43, which is an external terminal connecting the rectifier circuit 5 to the smoothing reactor 6, is located on the side of the module 8 facing the smoothing reactor 6 and is connected to the terminal 18 of the smoothing reactor 6 by, for example, welding.

[0028] Figure 4 shows the positional relationship between the housing 12, the water channel 13, the module 8, the inverter 4, and the rectifier circuit 5. The water channel 13, located inside the housing 12, is a flat-shaped water channel. The module 8 is positioned on the projection plane of the water channel 13 and mounted on the housing 12 via a cooling material 19 such as grease or gap filler. The semiconductor switching elements 4a to 4d that constitute the inverter 4 and the diodes 5a and 5b that constitute the rectifier circuit 5 are cooled in the water channel 13 via the cooling material 19 and the housing 12.

[0029] According to the above embodiment, by encapsulating the semiconductor switching elements 4a to 4d on the primary side of the DC / DC converter and the diodes 5a and 5b on the secondary side in the same package module 8, it becomes unnecessary to have a secondary-side specific cooling structure such as sheet metal for mounting the discrete package, or fixing bushings, screws, or insert resin to ensure the flatness or strength of the sheet metal, which was required when diodes 5a and 5b were in discrete packages. This reduces the number of parts and makes the cooling configuration inexpensive. Furthermore, the reduction in the number of parts leads to miniaturization, which reduces the area required for cooling, and by making the housing 12 smaller, the diodes 5a and 5b can be cooled inexpensively.

[0030] In addition, by integrating the primary side semiconductor switching elements 4a-4d, which require cooling, with the secondary side diodes 5a-5b using the same semiconductor chip as the secondary side diodes 5a-5b, the cooling plate 9 can be shared with the semiconductor switching elements 4a-4d, thereby reducing the cost of cooling the diodes 5a-5b. Furthermore, by sharing the insulating material 10 with the semiconductor switching elements 4a-4d, which require isolation from the housing 12, the cost of insulating the diodes 5a-5b from the housing 12 can be reduced.

[0031] In this embodiment, the center tap of transformer 2 is connected to GND, and the diodes 5a and 5b are at a potential different from GND, but this can also be applied to a circuit configuration in which the center tap of transformer 2 is connected to smoothing reactor 6, and the anode terminals of diodes 5a and 5b are connected to GND. In that case, the anodes of diodes 5a and 5b may be connected to cooling plate 9, so the insulating member 10 on the projection surface of lead frames 47a and 47b on which the anode terminals of diodes 5a and 5b are mounted becomes unnecessary, thus enabling cost reduction.

[0032] In this embodiment, since the primary semiconductor switching elements 4a to 4d constitute a full-bridge circuit, the number of elements is large, eliminating the need for package portions other than the chip and the clearance between packages required for discrete semiconductors. This results in a high degree of miniaturization by encapsulating the semiconductor switching elements 4a to 4d and the secondary diodes 5a and 5b in the same package module 8. As a result, the area required for cooling can be reduced, and the cooler can be made smaller. Furthermore, since full-bridge circuits can generally handle high output power, in applications requiring high output power where the cooling structure of the secondary diodes 5a and 5b would be a major cost factor, the number of components in the cooling structure can be reduced, resulting in a highly cost-effective cooling configuration.

[0033] In this embodiment, since diodes 5a and 5b are used as secondary rectifier elements, gate terminals required for switching elements such as MOSFETs are unnecessary, and because the number of terminals is small, the size of the module 8 in the longitudinal direction where the external terminals are arranged is not limited by the number of terminals, and the module 8 can be made smaller. As a result, the area required for cooling can be reduced, and the cooler can be made smaller.

[0034] In this embodiment, the lead frames 43, 44, 42a-42d, 45a-45d, 46a-46d, 47a, and 47b, which are the external terminals of module 8, are arranged along two sides of module 8. This allows for miniaturization of the module 8 in the longitudinal direction without being constrained by strength issues that arise when they are concentrated on one side, or by clearance issues between the terminal width and external terminals due to heat generation from conductive current. Furthermore, in order to shorten the lead frames and bonding wires, semiconductor switching elements 4a-4d and diodes 5a and 5b are usually placed near the corresponding external terminals. By arranging the external terminals along two sides of module 8, the mounting areas of the semiconductor switching elements 4a-4d and diodes 5a and 5b can be brought closer together. This reduces the area required for cooling, allowing for a smaller cooler.

[0035] Furthermore, in this embodiment, the direction in which the inverter 4, composed of semiconductor switching elements 4a to 4d, and the rectifier circuit 5, composed of diodes 5a and 5b, are aligned is the same as the direction in which the external terminals are aligned (i.e., the longitudinal direction of the module 8). Therefore, the lead frames 42a to 42d, 44, 45a to 45d, and 46a to 46d, which are external terminals connected to the inverter 4 composed of semiconductor switching elements 4a to 4d, can be placed close to the inverter 4. In addition, the lead frames 43, 47a, and 47b, which are external terminals connected to the rectifier circuit 5 composed of diodes 5a and 5b, can be placed close to the rectifier circuit 5. This suppresses the increase in size of the module 8 due to unnecessary wiring, and also suppresses noise or surges caused by long wiring.

[0036] Furthermore, in this embodiment, lead frames 42a, 42c, and 44, which are input external terminals connected to the DC power supply 1 of the inverter 4 composed of semiconductor switching elements 4a to 4d, are located on the first side (bottom edge in Figure 2) of the module 8, and lead frames 42b and 42d, which are output external terminals connected to the primary winding 2a of the transformer 2 of the inverter 4, are located on the second side (top edge in Figure 2) of the module 8. In addition, lead frames 47a and 47b, which are input external terminals connected to the secondary winding 2b of the transformer 2 of the rectifier circuit 5 composed of diodes 5a and 5b, are located on the second side (top edge in Figure 2) of the module 8, and lead frame 43, which is an output external terminal connected to the smoothing reactor 6 of the rectifier circuit 5, is located on the first side (bottom edge in Figure 2) of the module 8. As a result, the input and output external terminals of the inverter 4 and the rectifier circuit 5 can be arranged on different sides of the module 8, and the longitudinal length of the module 8 can be reduced.

[0037] Furthermore, in order to shorten the lead frames or bonding wires, semiconductor switching elements 4a-4d and diodes 5a and 5b are usually placed near the corresponding external terminals. By placing the external terminals on two sides of module 8, the mounting areas of the semiconductor switching elements 4a-4d and diodes 5a and 5b can be brought closer together, reducing the area required for cooling and allowing for a smaller cooler. In addition, since the lead frames 42b, 42d, 47a, and 47b, which are external terminals connected to transformer 2, are located on the second side of module 8 (the top side in Figure 2), the connection wiring to transformer 2 can be shortened, resulting in lower costs.

[0038] In this embodiment, an example is shown where the lead frames 42a-42d, 43, 44, 45a-45d, 46a-46d, 47a, and 47b, which are external terminals of module 8, are arranged along two sides of module 8. However, some of the lead frames, which are external terminals, may be arranged in the shorter direction. For example, lead frames 42a, 42c, and 44, which are input external terminals connected to the DC power supply 1 of the inverter 4 composed of semiconductor switching elements 4a-4d, may be located on the third side of module 8 (the left side in Figure 2), and lead frame 43, which is an output external terminal connected to the smoothing reactor 6 of the rectifier circuit 5 composed of diodes 5a and 5b, may be located on the fourth side of module 8 (the right side in Figure 2). If the connection interface with the DC power supply 1 is located to the left in Figure 2 of module 8, or if the smoothing reactor 6 is located to the right in Figure 2 of module 8, the connection wiring between module 8 and the DC power supply 1, or between module 8 and the smoothing reactor 6, can be shortened, thereby reducing costs.

[0039] In this embodiment, since the module 8, which is composed of a housing 12 and a water channel 13, has a cooler for cooling it, for example, in applications with high output power, if the size of the lead frames 42a to 42d and 43 is restricted in order to improve the heat dissipation of the semiconductor switching elements 4a to 4d and diodes 5a and 5b, the lead frames 42a to 42d and 43 can be made smaller, the module 8 can be miniaturized, and the cooler composed of the housing 12 and water channel 13 can be made smaller. As a result, the cost of the power conversion device 100 can be reduced.

[0040] Furthermore, since the cooling water flows perpendicular to the direction in which the inverter 4 and rectifier circuit 5 of module 8 are aligned, the inverter 4 and rectifier circuit 5 of module 8 are not affected by the cooling water's temperature rise due to the heat generated by each other. This suppresses the temperature rise, allowing module 8 to be miniaturized. As a result, the cooler, which consists of the housing 12 and the waterway 13, can be miniaturized, and the power conversion device 100 can be made less expensive.

[0041] Furthermore, because a portion of the transformer 2 and the smoothing reactor 6 are outside the projection plane of the water channel 13, the cooling area relative to the height is larger than that of the transformer 2 and the smoothing reactor 6. Therefore, the inverter 4 and rectifier circuit 5 of module 8, which have high cooling efficiency in the water channel 13, can be preferentially placed in the water channel 13, allowing module 8 to be miniaturized, and the cooler composed of the housing 12 and the water channel 13 can be miniaturized. As a result, the cost of the power conversion device 100 can be reduced.

[0042] Embodiment 2. Next, a power conversion device according to Embodiment 2 will be described. Figure 5 is a circuit diagram of the power conversion device according to Embodiment 2. As shown in Figure 5, the power converter 300 according to Embodiment 2 is configured by combining the power converter 100 described in Embodiment 1 with a power converter 200 which is equipped with inverters 62 and 63 that drive, for example, motors 60 and 61 for vehicle drive.

[0043] An input capacitor 64 is connected in parallel with the DC power supply 1 to stabilize the DC input voltage, and a boost reactor 65 is connected to the positive side of the input capacitor 64. The output of the boost reactor 65 is connected to the midpoint of a half-bridge switching element 66, and the boost reactor 65 and the half-bridge switching element 66 constitute a boost chopper. The output of the half-bridge switching element 66 is smoothed by a smoothing capacitor 67. An inverter 62 is connected to the smoothing capacitor 67 as its input, and the three-phase output line of the inverter 62 is connected to the motor 60. In addition, a regenerative inverter 63 is connected in parallel with the inverter 62, and motor 61 is connected via a three-phase line. By increasing the voltage with the boost chopper composed of the boost reactor 65 and the half-bridge switching element 66, the current in the wiring from the smoothing capacitor 67 to inverters 62 and 63, and the current from inverters 62 and 63 to motors 60 and 61 respectively can be reduced under the same power conditions. This allows for thinner wiring, resulting in cost reduction and weight reduction. The half-bridge switching element 66 is, for example, an IGBT with diodes connected in antiparallel.

[0044] The internal structure of module 8 of the power converter 100 and the mounting structure of the power converter 100, which constitute the power converter 300 of this embodiment, are the same as those in Figures 2 and 3, respectively, and a detailed explanation is omitted. Figure 6 shows the positional relationship between the housing 12, the waterway 13, module 8 of the power converter 100, and the required components of the power converter 200, and is a diagram that explains only the differences from Figure 4. Components that are the same as in Figure 4 are indicated using the same reference numerals.

[0045] In Figure 6, the housing 12 is provided with, for example, a flat-shaped water channel 13. On the second surface 69, which is parallel to the first surface 68 on which the module 8 of the power converter 100 inside the housing 12 is mounted, half-bridged switching elements 66 and inverters 62 and 63 are mounted via a second cooling member 70 such as grease or gap filler. In Figure 6, the input capacitor 64, the boost reactor 65, and the smoothing capacitor 67 are omitted. The half-bridged switching elements 66 and inverters 62 and 63 are each modularized and arranged in the same direction as the inverter 4 and rectifier circuit 5 of module 8. The half-bridged switching elements 66 and inverters 62 and 63 have cooling surfaces with the same structure as module 8, and these cooling surfaces face the second cooling member 70. The arrangement of the half-bridged switching elements 66 and inverters 62 and 63 is just an example, and any arrangement is acceptable. Furthermore, fins 72 are positioned on the third surface 71 of the water channel 13, which faces the second surface 69 of the housing 12, in order to increase the cooling capacity of the second surface 69 of the housing 12. The heat generated by the half-bridged switching element 66 and inverters 62 and 63 is dissipated into the water channel 13 via the second cooling member 70, the housing 12, and the fins 72.

[0046] Figure 7 is a plan view showing the positional relationship between the waterway 13 and the fins 72, the module 8 that constitutes the power converter 100, and the half-bridge switching elements 66 and inverters 62 and 63 that constitute the power converter 200. Fins 72 are located in the water channel 13 on the projection plane of the half-bridge switching element 66 and inverters 62 and 63, and module 8 is positioned on the projection plane of the fins 72. Cooling water enters the water channel 13 from the inlet 14, flows through the area where the fins 72 are located, and exits to the outlet 15. Generally, the power converter 200 that drives the motors 60 and 61 that power an electric vehicle has a higher output power than the power converter 100, which is a DC / DC converter that charges the lead-acid battery in an electric vehicle. Therefore, in order to miniaturize the half-bridge switching element 66 and inverters 62 and 63 that make up the power converter 200, fins 72 are provided in the water channel 13 on the side where the power converter 200 is mounted.

[0047] According to this embodiment, since the module 8 constituting the power converter 100 is mounted on one first surface 68 of the flattened water channel 13, and the half-bridge switching element 66 and inverters 62 and 63 constituting the power converter 200 are mounted on the other second surface 69, both sides of the water channel 13 can be effectively used as cooling surfaces, making it possible to miniaturize the cooler composed of the housing 12 and the water channel 13, and thus reducing the cost of the cooler. Furthermore, it is not necessary to provide a water channel 13 for each of the power converter 100 and the power converter 200, thus reducing the cost of the water channel 13. In this embodiment, an example is shown in which the half-bridge switching element 66 and inverters 62 and 63 constituting the power converter 200 are mounted on the second surface 69, but the same effect can be obtained by mounting the input capacitor 64, the boost reactor 65, and the smoothing capacitor 67.

[0048] Furthermore, since the cooling surface of module 8 constituting the power converter 100 and the cooling surfaces of the half-bridge switching element 66, inverter 62, and 63 constituting the power converter 200 are arranged in opposing directions, the wide surface of the simple, flat-shaped water channel 13 can be used as a cooling surface, making it possible to reduce the cost of the cooler composed of the housing 12 and the water channel 13.

[0049] Furthermore, since the orientation of the inverter 4 and rectifier circuit 5 of module 8 constituting the power converter 100 is the same as the orientation of the half-bridge switching elements 66, inverters 62 and 63 constituting the power converter 200, the longitudinal direction of the cooling area required for module 8 and the half-bridge switching elements 66 and inverters 62 and 63 can be unified with the longitudinal direction of the water channel 13. This reduces the cooling area of ​​the water channel 13 and makes it possible to reduce the cost of the cooler composed of the housing 12 and the water channel 13.

[0050] Furthermore, since the cooling water flows perpendicular to the direction in which the inverter 4 and rectifier circuit 5 of module 8 constituting the power converter 100 are aligned, and perpendicular to the direction in which the half-bridged switching element 66 and inverters 62 and 63 constituting the power converter 200 are aligned, the inverter 4 and rectifier circuit 5 of module 8, and the half-bridged switching element 66 and inverters 62 and 63 are not affected by the cooling water whose temperature rises due to the heat generated by each other, thus suppressing the temperature rise and allowing for miniaturization of module 8, or the half-bridged switching element 66 and inverters 62 and 63. As a result, the cooler, which consists of the housing 12 and the waterway 13, can be miniaturized, and the power converter 100 and power converter 200 can be made less expensive.

[0051] Furthermore, because the module 8 constituting the power converter 100 is positioned on the projection plane of the fin 72, the cooling capacity of the mounting surface is also increased for the module 8 constituting the power converter 100 on the side where the fin 72 is not provided, due to the increased flow rate of the cooling water caused by the fin 72. As a result, the heat-generating components of the power converter 100, including module 8, that are located on the projection plane of the fin 72 can be miniaturized, and costs can be reduced.

[0052] Furthermore, because a portion of the transformer 2 or smoothing reactor 6 constituting the power converter 100 is located outside the projection plane of the water channel 13 or fins 72, the inverter 4 and rectifier circuit 5 of module 8, or the half-bridged switching element 66 and inverters 62, 63, which have a larger cooling area relative to their height than the transformer 2 or smoothing reactor 6, can be preferentially placed in the flattened water channel 13, resulting in higher cooling efficiency. This allows for miniaturization of module 8, or the half-bridged switching element 66 and inverters 62, 63. Consequently, the cooler, which consists of the housing 12 and the water channel 13, can be miniaturized, and the power converter 100 and power converter 200 can be made less expensive.

[0053] In this embodiment, a flattened water channel 13 is shown, and the water channel for cooling the power converter 100 and the water channel for cooling the power converter 200 are the same. However, as shown in Figure 8, the water channel 13 may be divided by providing a partition 73 of the housing 12 on a surface parallel to the plane of the water channel 13, so that the water channel for cooling the modules 8 that make up the power converter 100 and the water channels for cooling the half-bridge switching elements 66 and inverters 62 and 63 that make up the power converter 200 are separate.

[0054] As described above, even in a configuration where the optimal water channel can be applied to module 8 and the half-bridged switching element 66 and inverters 62 and 63, by effectively using both sides of the water channel 13 as cooling surfaces, the cooler composed of the housing 12 and the water channel 13 can be miniaturized, and the cost of the cooler can be reduced.

[0055] In this embodiment, an example is shown where the projection planes of module 8 constituting power converter 100 and half-bridged switching element 66 and inverters 62 and 63 constituting power converter 200 overlap, but there may be areas where the projection planes do not overlap. Since thermal interference between module 8 and half-bridged switching element 66 and inverters 62 and 63 is reduced, the temperature rise can be suppressed. In addition, module 8, or half-bridged switching element 66 and inverters 62 and 63 can be miniaturized, and the cooler consisting of the housing 12 and water channel 13 can be miniaturized. As a result, the power converter 100 and power converter 200 can be made less expensive.

[0056] In this embodiment, an example is shown in which a boost chopper and inverters 62 and 63 are used as the power conversion device 200. However, the boost chopper may be omitted, and only one inverter may be used. The power conversion device 200 may also be an on-board charger. In that case, the input to the on-board charger is the AC voltage of the grid, and the output is connected to the DC power supply 1, so the power conversion device 200 is connected to the output of the on-board charger.

[0057] While this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are envisioned within the scope of the art disclosed herein. For example, these include modifying, adding or omitting at least one component, or even extracting at least one component and combining it with a component from another embodiment.

[0058] The various aspects of this disclosure are summarized below as an appendix.

[0059] (Note 1) Multiple semiconductor switching elements that convert the DC voltage of a DC power supply to an AC voltage, An isolation transformer that transmits the aforementioned AC voltage from the primary side to the secondary side and outputs it, The system comprises a rectifier circuit including a plurality of rectifier elements for rectifying the output, A power conversion device characterized in that the plurality of semiconductor switching elements and the plurality of rectifier elements are composed of modules sealed in the same package. (Note 2) The power conversion device according to Appendix 1, characterized in that the plurality of semiconductor switching elements constitute a full bridge circuit. (Note 3) The power conversion device according to Appendix 1 or 2, characterized in that the plurality of rectifier elements are diodes. (Note 4) The power conversion device according to any one of the appendices 1 to 3, characterized in that the module comprises a cooling member for cooling the plurality of semiconductor switching elements and the plurality of rectifier elements, and an insulating member for insulating at least one of the plurality of semiconductor switching elements and the plurality of rectifier elements from the cooling member. (Note 5) The module has an external terminal for connecting the plurality of switching elements, the plurality of rectifier elements, and an external circuit. The power conversion device according to any one of the appendices 1 to 4, characterized in that the external terminals are arranged on at least two sides of the module. (Note 6) The power conversion device according to Appendix 5, wherein the external terminals include a primary external terminal for connecting the plurality of switching elements and the external circuit, and a secondary external terminal for connecting the plurality of rectifier elements and the external circuit, the primary external terminals are arranged on both sides of the module with respect to the mounting area of ​​the plurality of switching elements, and the secondary external terminals are arranged on both sides of the module with respect to the mounting area of ​​the plurality of rectifier elements. (Note 7) The power conversion device according to Appendix 6, characterized in that the primary external terminal and the secondary external terminal are arranged in the same direction as the mounting area of ​​the plurality of switching elements and the mounting area of ​​the plurality of rectifier elements. (Note 8) The power conversion device according to Appendix 6 or 7, characterized in that, of the primary side external terminals, the primary side DC input terminal connected to the DC power supply is located on the first side of the module, and the primary side AC output terminal connected to the isolation transformer is located on the side opposite to the first side. (Note 9) The power conversion device according to Appendix 6 or 7, characterized in that, of the secondary external terminals, the secondary AC input terminal connected to the isolation transformer is located on the second side of the module, and the secondary DC output terminal connected to the load via the rectifier circuit is located on the opposite side of the second side. (Note 10) The power conversion device according to any one of claims 6 to 9, characterized in that the primary AC output terminal connected to the isolation transformer among the primary external terminals and the secondary AC input terminal connected to the isolation transformer among the secondary external terminals are arranged on the same side of the module. (Note 11) The power conversion device according to any one of the appendices 1 to 10, characterized in that it has a cooler for cooling the module, the isolation transformer, and the rectifier circuit. (Note 12) The power conversion device according to Appendix 11, wherein the power conversion device is configured in combination with a second power conversion device, the module is mounted on the first surface of the cooler, and at least one heat-generating component constituting the second power conversion device is mounted on the second surface, which is the opposite surface of the first surface. (Note 13) The power conversion device according to Appendix 12, characterized in that the heat-generating component is a plurality of semiconductor switching elements constituting the second power conversion device. (Note 14) The power conversion device according to Appendix 13, characterized in that the cooling surface of the module faces the cooling surfaces of a plurality of semiconductor switching elements constituting the second power conversion device via the cooler. (Note 15) The power converter according to Appendix 13, characterized in that the orientation in which the mounting regions of the plurality of semiconductor switching elements constituting the power converter and the mounting regions of the plurality of rectifier elements are aligned is the same as the orientation in which the plurality of semiconductor switching elements constituting the second power converter are aligned. (Note 16) The power conversion device according to any one of the appendices 11 to 15, characterized in that the cooler has a water channel, and the direction of flow of the refrigerant flowing through the water channel is perpendicular to the direction in which the mounting areas of the plurality of semiconductor switching elements constituting the power conversion device and the mounting areas of the plurality of rectifier elements are aligned. (Note 17) The power converter according to any one of the appendices 12 to 15, characterized in that, when viewed from the stacking direction in which the module and the cooler are stacked, at least a portion thereof overlaps with the area of ​​cooling fins provided on the cooler on the second power converter side. (Note 18) The power conversion device according to any one of the appendices 11 to 15, 17, characterized in that the cooler has a water channel, and at least a portion of the smoothing reactor for smoothing the output current of the isolation transformer or the plurality of rectifier elements is outside the region containing the water channel when viewed from the stacking direction in which the module and the cooler are stacked. [Explanation of Symbols]

[0060] 1 DC power supply, 2 Transformer, 2a Primary winding, 2b Secondary winding, 3 Load, 4 Inverter, 4a~4d Semiconductor switching element, 5 Rectifier circuit, 5a, 5b Diode, 6 Smoothing reactor, 7 Smoothing capacitor, 8 Module, 9 Cooling plate, 10 Insulating material, 11 Resin, 12 Enclosure, 13 Water channel, 14 Inlet, 15 Outlet, 16 Circuit board, 17 Wiring, 18, 53~56 Terminals, 19 Cooling material, 40a~40d Gate pad, 41a~41d Source pad, 42a~42d, 43, 44, 45a~45d, 46a~46d, 47a, 47b Lead frame, 48a~48d, 49a~49d, 50a~50d, 52a, 52b Wire bonding, 51a, 51b Anode pad, 60, 61 Motor, 62, 63 Inverter, 64 Input capacitor, 65 Boost reactor, 66 Switching element, 67 Smoothing capacitor, 68 First surface, 69 Second surface, 70 Second cooling element, 71 Third surface, 72 Fin, 73 Partition, 100, 200, 300 Power converter, Vin, Vout DC voltage.

Claims

1. Multiple semiconductor switching elements that convert the DC voltage of a DC power supply to an AC voltage, An isolation transformer that transmits the aforementioned AC voltage from the primary side to the secondary side and outputs it, The system comprises a rectifier circuit including a plurality of rectifier elements for rectifying the output, The plurality of semiconductor switching elements and the plurality of rectifier elements are composed of modules sealed in the same package. The module has an external terminal for connecting the plurality of switching elements, the plurality of rectifier elements, and an external circuit. The external terminal is configured to include a primary external terminal that connects the plurality of switching elements to the external circuit, and a secondary external terminal that connects the plurality of rectifier elements to the external circuit. A power conversion device characterized in that, among the primary side external terminals, the primary side AC output terminal connected to the isolation transformer and among the secondary side external terminals, the secondary side AC input terminal connected to the isolation transformer are arranged on the same side of the module.

2. The power conversion device according to claim 1, characterized in that the plurality of semiconductor switching elements constitute a full bridge circuit.

3. The power conversion device according to claim 1 or 2, characterized in that the plurality of rectifier elements are diodes.

4. The power conversion device according to claim 1 or 2, characterized in that the module comprises a cooling member for cooling the plurality of semiconductor switching elements and the plurality of rectifier elements, and an insulating member for insulating at least one of the plurality of semiconductor switching elements and the plurality of rectifier elements from the cooling member.

5. The power conversion device according to claim 1 or 2, characterized in that the external terminals are arranged on at least two sides of the module.

6. The power conversion device according to claim 5, characterized in that the primary external terminals are arranged on both sides of the module, flanking the mounting areas of the plurality of switching elements, and the secondary external terminals are arranged on both sides of the module, flanking the mounting areas of the plurality of rectifier elements.

7. The power conversion device according to claim 6, characterized in that the primary external terminal and the secondary external terminal are arranged in the same direction as the mounting area of ​​the plurality of switching elements and the mounting area of ​​the plurality of rectifier elements.

8. The power conversion device according to claim 6, characterized in that, of the primary side external terminals, the primary side DC input terminal connected to the DC power supply is located on the first side of the module, and the primary side AC output terminal connected to the isolation transformer is located on the side opposite to the first side.

9. The power conversion device according to claim 6, characterized in that, of the secondary external terminals, the secondary AC input terminal connected to the isolation transformer is located on the second side of the module, and the secondary DC output terminal connected to the load via the rectifier circuit is located on the opposite side of the second side.

10. The power conversion device according to claim 1 or 2, characterized in that the power conversion device has a semiconductor switching element, an isolation transformer, and a cooler for cooling the rectifier circuit.

11. Multiple semiconductor switching elements that convert the DC voltage of a DC power supply to an AC voltage, An isolation transformer that transmits the aforementioned AC voltage from the primary side to the secondary side and outputs it, The rectifier circuit includes a plurality of rectifier elements that rectify the output, The plurality of semiconductor switching elements and the plurality of rectifier elements are composed of modules sealed in the same package. The module has an external terminal for connecting the plurality of switching elements, the plurality of rectifier elements, and an external circuit. The external terminal is configured to include a primary external terminal that connects the plurality of switching elements to the external circuit, and a secondary external terminal that connects the plurality of rectifier elements to the external circuit. The first power converter is characterized in that, among the primary side external terminals, the primary side AC output terminal connected to the isolation transformer and the secondary side external terminal connected to the isolation transformer are arranged on the same side of the module. A second power converter having a greater output power than the first power converter, A power conversion device comprising a cooler on which the module is mounted on the first surface and on the second surface, which is opposite to the first surface, on which at least one heat-generating component constituting the second power conversion device is mounted, The power conversion device is characterized in that the cooler has a water channel inside, and a fin is provided on a third surface in the water channel that faces the second surface.

12. The power conversion device according to claim 11, characterized in that the heat-generating component is a plurality of semiconductor switching elements constituting the second power conversion device.

13. The power conversion device according to claim 12, characterized in that the cooling surface of the module faces the cooling surfaces of a plurality of semiconductor switching elements constituting the second power conversion device via the cooler.

14. The power converter according to claim 12, characterized in that the direction in which the mounting regions of the plurality of semiconductor switching elements constituting the first power converter and the mounting regions of the plurality of rectifier elements are aligned is the same as the direction in which the plurality of semiconductor switching elements constituting the second power converter are aligned.

15. The power conversion device according to claim 10, wherein the cooler has a water channel, and the direction of flow of the refrigerant flowing through the water channel is perpendicular to the direction in which the mounting regions of the plurality of semiconductor switching elements and the mounting regions of the plurality of rectifier elements constituting the power conversion device are aligned.

16. The power converter according to claim 11, characterized in that, when viewed from the stacking direction in which the module and the cooler are stacked, at least a portion thereof overlaps with the area of ​​cooling fins provided on the cooler on the second power converter side.

17. The power conversion device according to claim 10, wherein the cooler has a water channel, and the smoothing reactor for smoothing the output current of the isolation transformer or the plurality of rectifier elements is such that, when viewed from the stacking direction in which the module and the cooler are stacked, at least a portion thereof is outside the region containing the water channel.

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