Power conversion device

Abstract

Provided is a power conversion device that includes at least two systems of secondary side rectifier circuits and that can suppress electromagnetic coupling to surrounding circuits. The power conversion device comprises, in the same housing, a substrate on which a main circuit is disposed, and a control circuit that controls the main circuit, the power conversion device characterized in that: the main circuit includes at least two systems of rectifier circuit units of a first system and a second system; power is input to each of the rectifier circuit units of the first system and the second system via transformers; power having a reverse phase to that of the input power of the rectifier circuit unit of the first system is input to the rectifier circuit unit of the second system; the same power as that of the input power is set to an output of the rectifier circuit unit of the first system and an output of the rectifier circuit unit of the second system; and a collection surface of midpoints between components of the rectifier circuit unit of the first system and components of the rectifier circuit unit of the second system and a collection surface of midpoints between a conductive member of the rectifier circuit unit of the first system and a conductive member of the rectifier circuit unit of the second system are disposed side by side on an equidistant line between the rectifier circuit unit of the first system and the rectifier circuit unit of the second system.

Description

Power converter

[0001] This invention relates to the configuration of a power conversion device, and more particularly to a technology that is effective when applied to in-vehicle power conversion devices that require high reliability and miniaturization and weight reduction.

[0002] As autonomous driving levels become more sophisticated, power conversion devices such as DC / DC converters are required to be redundant for fail-safe purposes. Furthermore, due to space limitations and efficiency considerations for mounting DC / DC converters, there is a demand for structures that integrate on-board chargers and AC outputs (V2L) into the DC / DC converter, and high-density mounting is required for further miniaturization.

[0003] On the other hand, achieving redundancy and miniaturization requires the close placement of electronic components. This results in electromagnetic coupling between components, increasing electromagnetic noise. High-density mounting within power converters brings components into close proximity, causing electromagnetic coupling, which can lead to circuit malfunctions or necessitate the addition of EMC (Electromagnetic Compatibility) components.

[0004] As background technology to this field, for example, there is technology such as that described in Patent Document 1. Patent Document 1 discloses a "DC-DC converter device that reduces conduction losses caused by differences in current distribution in a rectifier circuit in which multiple rectifier elements are connected in parallel."

[0005] Patent Document 1 describes how current imbalance is suppressed and losses are reduced by arranging parallel-connected secondary rectifier MOSs symmetrically for a single output system.

[0006] Japanese Patent Publication No. 2014-121117

[0007] As mentioned above, in recent years, power converters have been required to be redundant, with multiple (for example, two) outputs arranged within the same enclosure. To achieve miniaturization, it is necessary to mount electronic components at high density, but there are concerns that the magnetic fields generated by the current flowing through components such as busbars may electromagnetically couple to nearby circuits.

[0008] In the above-mentioned Patent Document 1, the rectifier MOS of the parallel-connected secondary circuit is arranged symmetrically to equalize the total current paths of the input and output, thereby reducing losses.

[0009] However, Patent Document 1 is a self-contained description of a single converter and does not assume a redundant configuration with multiple converters. Furthermore, it does not describe how to suppress electromagnetic coupling such as magnetic fields. Therefore, in the configuration of Patent Document 1, the magnetic field will electromagnetically couple to the surrounding circuitry, and if nearby circuits, especially components equipped with control circuits, are placed in close proximity, it may cause malfunctions in the control circuits or necessitate enhanced EMC countermeasures.

[0010] Therefore, an object of the present invention is to provide a power converter having at least two secondary rectifier circuits that can suppress electromagnetic coupling to surrounding circuits.

[0011] To solve the above problems, the present invention provides a power conversion device comprising a circuit board on which a main circuit is arranged and a control circuit for controlling the main circuit, wherein the main circuit has at least two rectifier circuit sections, a first system and a second system, power is input to each of the first and second rectifier circuit sections via a transformer, power in the opposite phase to the input power of the first system is input to the second system rectifier circuit section, the same power as the input power is set for the output of the first system rectifier circuit section and the output of the second system rectifier circuit section, and the plane of the midpoints of the components of the first system rectifier circuit section and the components of the second system rectifier circuit section, and the plane of the midpoints of the conductive members of the first system rectifier circuit section and the conductive members of the second system rectifier circuit section are arranged on equidistant lines between the first system rectifier circuit section and the second system rectifier circuit section.

[0012] According to the present invention, a power converter having at least two secondary rectifier circuits can be realized that can suppress electromagnetic coupling to surrounding circuits.

[0013] This can contribute to improving the reliability and miniaturizing / lightening power conversion devices.

[0014] Other issues, configurations, and effects not mentioned above will be clarified by the following description of the embodiments.

[0015] This is a circuit diagram showing the schematic configuration of a power converter according to Embodiment 1 of the present invention. This is a diagram showing an example of the component layout of the transformers 4a, 4b and secondary circuit 5 of the power converter 1 in Figure 1. This is a cross-sectional view taken along A-A' in Figure 2A. This is a diagram showing an example of the component layout of the transformers 4a, 4b and secondary circuit 5 of the power converter according to Embodiment 2 of the present invention. This is a circuit diagram showing the schematic configuration of a power converter according to Embodiment 3 of the present invention. This is a diagram showing an example of the component layout of the transformer 4 and secondary circuit 5 of the power converter 1 in Figure 4. This is a diagram showing an example of the component layout of the transformers 4a, 4b and secondary circuit 5 of the power converter according to Embodiment 4 of the present invention. This is a cross-sectional view taken along B-B' in Figure 6A. This is a diagram showing an example of the component layout of the secondary circuit 5 of the power converter according to Embodiment 5 of the present invention.

[0016] Embodiments of the present invention will be described below with reference to the drawings. In each drawing, identical components are denoted by the same reference numerals, and detailed descriptions of overlapping parts are omitted.

[0017] A power conversion device according to Embodiment 1 of the present invention will be described with reference to Figures 1 to 2B.

[0018] Figure 1 is a circuit diagram showing the schematic configuration of the power converter 1 of this embodiment. Figure 2A is a diagram showing an example of the component layout of the transformers 4a, 4b and the secondary circuit 5 of the power converter 1 of Figure 1. Figure 2B is a cross-sectional view taken along line A-A' of Figure 2A. However, in order to make the structure easier to understand, Figure 2A excludes the circuit boards 12, 14 and the control component 15, and Figure 2B excludes the semiconductor switches M1 to M4.

[0019] As shown in Figure 1, the power converter 1 of this embodiment is a DC / DC converter in which the secondary circuit 5 consists of two systems, and the high voltage V is the output of the high voltage DC power supply 2. ＨＶＢＡＴ These are low voltage outputs 1 (8) and 2 (9), which are low voltage V ＬＶＢＡＴThis is a device that converts between DC and AC. Each system consists of a primary circuit 3 which is a DC / AC converter, a transformer 4 (transformers 4a, 4b) that magnetically couples the primary and secondary sides, and a secondary circuit 5 which is an AC / DC converter. The secondary circuit 5 has a rectifier circuit section for the first system 6 which is coupled to the primary circuit 3 via transformer 4a, and a rectifier circuit section for the second system 7 which is coupled to the primary circuit 3 via transformer 4b.

[0020] The primary circuit 3, transformer 4, and secondary circuit 5 that constitute the main circuit are housed together in the same enclosure (not shown) along with the circuit board 12 on which these circuits are mounted, and the circuit board 14 on which the control components 15 are mounted, to form the power conversion device 1.

[0021] The primary circuit 3 consists of a half-bridge circuit or a full-bridge circuit using a semiconductor switch. The secondary circuit 5 consists of a half-bridge circuit or a full-bridge circuit using a semiconductor switch, or a half-wave rectifier circuit or a full-wave rectifier circuit using a diode. In Figure 1, the primary circuit 3 has a semiconductor switch Q. １ ~Q ４ An example of a full-bridge circuit using semiconductor switches M1 to M4 and diodes D1 to D4 is shown in the secondary circuit 5.

[0022] In this embodiment, the power converter 1 is characterized in that the first system 6 and the second system 7 of the secondary circuit 5 are input to complementary voltages with a phase difference of 180°. One method for setting the phase difference is to set the polarities of transformers 4a and 4b in opposite directions. As a result, the voltage applied to the second system 7 has a voltage waveform with the opposite polarity to the voltage applied to the first system 6, and the currents flowing through the first system 6 and the second system 7 are in opposite directions.

[0023] Using Figures 2A and 2B, we will explain an example of the component layout for transformers 4a and 4b and the secondary circuit 5.

[0024] Because a large current flows through the secondary circuit 5, metal busbars 10a, 10b and 11a, 11b are mounted on the substrate 12. Ideally, these conductive components such as busbars 10a, 10b and 11a, 11b should be placed close together on the forward and return paths to strengthen electromagnetic coupling and reduce leakage of magnetic fields to the surroundings. However, electronic components such as semiconductor switches M1 to M4 must be placed along the paths, and if the busbars are mounted far apart, some of the magnetic field leaks to the surroundings, causing electromagnetic coupling to the surrounding circuits.

[0025] Therefore, in the present invention, the voltages applied to the first system 6 and the second system 7 are set to be approximately equal, the voltages applied to the first system 6 and the voltages applied to the second system 7 are set to be opposite in polarity, and the components and conductive members of the second system 7 are arranged symmetrically with those of the components and conductive members of the first system 6.

[0026] As a result, as shown in Figure 2B, the leakage magnetic field generated by the secondary circuit 5 can be controlled to a position where the magnetic field on the equidistant line is canceled out, making it less susceptible to electromagnetic noise.

[0027] The power converter 1 of this embodiment is configured as described above, and includes a circuit board 12 on which the main circuit is arranged and a control circuit (circuit board 14 and control components 15) that controls the main circuit, all within the same housing. The main circuit has at least two rectifier circuit sections, a first system 6 and a second system 7. Power is input to each of the rectifier circuit sections of the first system 6 and the second system 7 via transformers 4a and 4b. Power that is in the opposite phase to the input power of the rectifier circuit section of the first system 6 is input to the rectifier circuit section of the second system 7. The output of the rectifier circuit section of the first system 6 and the output of the rectifier circuit section of the second system 7 are set to the same power as the input power. The planes of the midpoints of the components of the rectifier circuit section of the first system 6 and the components of the rectifier circuit section of the second system 7, and the planes of the midpoints of the conductive members of the rectifier circuit section of the first system 6 and the conductive members of the rectifier circuit section of the second system 7 are arranged on equidistant lines between the rectifier circuit section of the first system 6 and the rectifier circuit section of the second system 7. Here, "equidistance lines" refers to the dashed lines shown in Figures 2A and 2B.

[0028] The components of the rectifier circuit section of the first system 6 and the components of the rectifier circuit section of the second system 7, as well as the conductive members of the rectifier circuit section of the first system 6 and the conductive members of the rectifier circuit section of the second system 7, are arranged symmetrically across the plane of convergence of their respective midpoints.

[0029] In the example shown in Figure 2A, the components of the rectifier circuit section of the first system 6 include a first semiconductor switch M1, a second semiconductor switch M2 connected in parallel with the first semiconductor switch M1, a first capacitor C1, and a first inductor L1. The components of the rectifier circuit section of the second system 7 include a third semiconductor switch M3, a fourth semiconductor switch M4 connected in parallel with the third semiconductor switch M3, a second capacitor C2, and a second inductor L2.

[0030] Furthermore, the planes of the midpoints of the first semiconductor switch M1 and the fourth semiconductor switch M4, the planes of the midpoints of the second semiconductor switch M2 and the third semiconductor switch M3, the planes of the midpoints of the first capacitor C1 and the second capacitor C2, and the planes of the midpoints of the first inductor L1 and the second inductor L2 are arranged on equidistant lines between the rectifier circuit section of the first system 6 and the rectifier circuit section of the second system 7.

[0031] By using reverse-phase control and a symmetrical arrangement, the magnetic field generated by the busbar current can be canceled out. This cancellation effect of the magnetic field generated by the circuit suppresses electromagnetic coupling to surrounding circuits.

[0032] Furthermore, as shown in Figure 2B, the control circuit (board 14 and control components 15) is positioned at a predetermined distance from the board 12 on which the components and conductive members of the rectifier circuit of the first system 6 and the rectifier circuit of the second system 7 are mounted. This board is a collection of regions that are at equal distances from the plane where the midpoints of the corresponding components and conductive members of the rectifier circuit of the first system 6 and the rectifier circuit of the second system 7 are met.

[0033] By placing noise-sensitive integrated circuits (ICs) and circuit boards in locations where magnetic field cancellation effects can be obtained, it is possible to suppress noise effects while arranging components in close proximity, contributing to circuit miniaturization. Furthermore, a reduction in EMC countermeasures components such as electromagnetic shielding can be expected.

[0034] Referring to Figure 3, a power conversion device according to Embodiment 2 of the present invention will be described.

[0035] Figure 3 shows an example of the component layout of the transformers 4a and 4b and the secondary circuit 5 of the power converter 1 of this embodiment. As shown in Figure 3, the power converter 1 of this embodiment differs from Embodiment 1 (Figure 2A) in that snubber capacitors 13 are connected to the first system 6 and the second system 7 of the secondary circuit 5, respectively. The other configurations are the same as in Embodiment 1.

[0036] A snubber capacitor is a capacitor used to suppress transient phenomena and noise in power circuits. As shown in this embodiment (Figure 3), by connecting the snubber capacitor 13 to the first system 6 and the second system 7 of the secondary circuit 5, overvoltages and overcurrents associated with the switching operation of semiconductor switches M1 to M4 can be reduced, thereby protecting the components of the first system 6 and the second system 7 and stabilizing the signals.

[0037] A power conversion device according to Embodiment 3 of the present invention will be described with reference to Figures 4 and 5.

[0038] Figure 4 is a circuit diagram showing the schematic configuration of the power converter 1 of this embodiment. Figure 5 is a diagram showing an example of the component layout of the transformer 4 and secondary circuit 5 of the power converter 1 of Figure 4. In Embodiment 1 (Figure 1), power is input from the primary circuit 3 to the first system 6 and the second system 7 of the secondary circuit 5 via transformers 4a and 4b, respectively. In contrast, in this embodiment, the transformer 4 is a transformer coupled with a single core, and power is input from the primary circuit 3 to the first system 6 and the second system 7 of the secondary circuit 5 via a common transformer 4. The other configurations are the same as in Embodiment 1.

[0039] As in this embodiment, by adopting a configuration in which power is input from the primary circuit 3 to the first system 6 and the second system 7 of the secondary circuit 5 via the transformer 4 coupled by a single core, it is possible to contribute to the miniaturization of the circuit.

[0040] Referring to FIGS. 6A and 6B, a power conversion device according to Embodiment 4 of the present invention will be described.

[0041] FIG. 6A is a diagram showing an example of the component layout of the transformers 4a and 4b of the power conversion device 1 and the secondary circuit 5 of this embodiment. FIG. 6B is a cross-sectional view taken along line B - B′ of FIG. 6A. As shown in FIGS. 6A and 6B, the secondary circuit 5 of this embodiment has a plurality of bus bars (bus bars 10a, 11a, 16a) connected to the semiconductor switches (rectifying semiconductor elements) M1 and M2 of the rectifying circuit section of the first system 6, and the plurality of bus bars 10a, 11a, 16a are arranged to face each other with the substrate 12 interposed therebetween on the front and back surfaces of the substrate 12.

[0042] Further, it has a plurality of bus bars (bus bars 10b, 11b, 16b) connected to the semiconductor switches (rectifying semiconductor elements) M3 and M4 of the rectifying circuit section of the second system 7, and the plurality of bus bars 10b, 11b, 16b are arranged to face each other with the substrate 12 interposed therebetween on the front and back surfaces of the substrate 12. And a part of the bus bar of the first system 6 and a part of the bus bar of the second system 7 are shared.

[0043] As in this embodiment, by mounting the components and conductive members of the first system 6 and the components and conductive members of the second system 7 on both sides of the substrate 12 and further sharing a part of the bus bar, the rectifying circuit section of the first system 6 and the rectifying circuit section of the second system 7 can be arranged closer to each other, so that a magnetic field cancellation position due to symmetry can be generated at a closer position.

[0044] Referring to FIG. 7, a power conversion device according to Embodiment 5 of the present invention will be described.

[0045] Figure 7 shows an example of the component layout of the secondary circuit 5 of the power converter 1 of this embodiment. As shown in Figure 7, the secondary circuit 5 of this embodiment has a main circuit board on which the main circuit is mounted, which includes a first circuit board 18 on which the rectifier circuit section of the first system 6 is arranged, and a second circuit board 19 on which the rectifier circuit section of the second system 7 is arranged. The first circuit board 18 and the second circuit board 19 are arranged in a hierarchical manner in the vertical direction within a housing (not shown). The circuit board (control board) 14 on which the control components 15 are arranged is located at a predetermined distance from the first circuit board 18 and the second circuit board 19, and is positioned midway between the first circuit board 18 and the second circuit board 19.

[0046] As in this embodiment, the substrate 12 on which the main circuit is mounted is divided into a first substrate 18 on which the rectifier circuit section of the first system 6 is arranged, and a second substrate 19 on which the rectifier circuit section of the second system 7 is arranged, and by arranging them in a hierarchical structure, integrated circuits (ICs) and substrates that are susceptible to noise can be placed in locations where the magnetic field cancellation effect can be obtained, thereby enabling the mounting of components in close proximity while obtaining a noise suppression effect.

[0047] According to the embodiments of the present invention described above, electromagnetic coupling to surrounding circuits can be suppressed by the cancellation effect of the magnetic field generated from the circuit. Since electromagnetically coupled noise can be suppressed, it can contribute to miniaturization by placing circuits in close proximity and to reducing the number of components by optimizing EMC countermeasures components.

[0048] Although the above describes an example of the effects on the control circuit (board 14 and control components 15), the present invention is also effective for the arrangement of components other than the control circuit. For example, the power line that supplies power to the control circuit is also connected to other in-vehicle electronic equipment, so if unwanted electromagnetic noise is introduced, it may cause malfunctions in other devices, or the wiring connected to other devices may act as an antenna and emit electromagnetic radiation, potentially affecting receivers such as radios. By applying the present invention to the power line as well, it is possible to suppress the noise level caused by electromagnetic coupling from the secondary rectifier circuit.

[0049] Furthermore, the semiconductor switch Q in the primary circuit 3. １ ~Q ４Although the description has been made assuming a semiconductor device using a Si (silicon) substrate or a SiC (silicon carbide) substrate, when applying a semiconductor device using a GaN (gallium nitride) substrate and assuming a case where the switching frequency is increased, the value of the inductor L required becomes smaller, so the entire circuit can be miniaturized. Since the components can be miniaturized, each circuit of the first system 6 and the second system 7 can be arranged closer to each other, and there is a risk that the electromagnetic coupling between the circuits increases. However, the present invention has a structure that can be similarly applied even when a semiconductor device using a GaN substrate is adopted, and the electromagnetic coupling to the surrounding circuits can be suppressed by the canceling effect of the magnetic field generated from the circuit.

[0050] Note that the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, or replacement with other configurations is possible.

[0051] 1... Power conversion device, 2... High-voltage DC power supply (V ＨＶＢＡＴ ), 3... Primary-side circuit, 4, 4a, 4b... Transformer, 5... Secondary-side circuit, 6... First system, 7... Second system, 8... Low-voltage output 1 (V ＬＶＢＡＴ ), 9... Low-voltage output 2 (V ＬＶＢＡＴ ), 10, 10a, 10b, 11, 11a, 11b, 16, 16a, 16b... Bus bar, 12, 14, 18, 19... Substrate, 13... Snubber capacitor, 15... Control component, 17... Contact, C, C1, C2... Capacitor, D1 to D4... Diode, L, L1, L2... Inductor, M1 to M4, Q １ ~Q ４ ... Semiconductor switch, R... Resistor.

Claims

1. A power conversion device comprising a circuit board on which a main circuit is arranged and a control circuit for controlling the main circuit, wherein the main circuit has at least two rectifier circuit sections, a first system and a second system; power is input to each of the first and second rectifier circuit sections via a transformer; power is input to the second rectifier circuit section which is in opposite phase to the input power of the first rectifier circuit section; the output of the first rectifier circuit section and the output of the second rectifier circuit section are set to the same power as the input power; and the planes of the midpoints of the components of the first rectifier circuit section and the components of the second rectifier circuit section, and the planes of the midpoints of the conductive members of the first rectifier circuit section and the conductive members of the second rectifier circuit section are arranged on equidistant lines between the first rectifier circuit section and the second rectifier circuit section.

2. A power conversion device according to claim 1, characterized in that the components of the first rectifier circuit section and the components of the second rectifier circuit section, and the conductive members of the first rectifier circuit section and the conductive members of the second rectifier circuit section are arranged symmetrically across the plane of their respective midpoints.

3. A power conversion device according to claim 1, characterized in that the control circuit is located at a predetermined distance from a substrate on which the components and conductive members of the first and second rectifier circuits are mounted, wherein the control circuit is located at a predetermined distance from the substrate on which the components and conductive members of the first and second rectifier circuits are mounted.

4. A power conversion device according to claim 1, wherein the transformer is a transformer coupled with a single core.

5. A power conversion device according to claim 1, wherein the power conversion device has a plurality of first busbars connected to the rectifier semiconductor elements of the first rectifier circuit, the plurality of first busbars are arranged opposite each other on the front and back surfaces of the substrate with the substrate in between, and a plurality of second busbars connected to the rectifier semiconductor elements of the second rectifier circuit, the plurality of second busbars are arranged opposite each other on the front and back surfaces of the substrate with the substrate in between, and a portion of the first busbars and a portion of the second busbars are common.

6. A power conversion device according to claim 1, wherein the substrate comprises a first substrate on which the first rectifier circuit section is arranged and a second substrate on which the second rectifier circuit section is arranged, the first substrate and the second substrate are arranged in a hierarchical manner in the vertical direction within the housing, and the control substrate on which the control circuit is arranged is located at a predetermined distance from the first substrate and the second substrate, and is located at an intermediate position between the first substrate and the second substrate.

7. A power conversion device according to claim 1, wherein the power conversion device is a DC / DC converter, the main circuit comprises a primary DC / AC rectifier circuit section, the transformer, and a secondary AC / DC rectifier circuit section, and the secondary AC / DC rectifier circuit section comprises a first rectifier circuit section and a second rectifier circuit section.

8. A power conversion device according to claim 1, wherein the components of the first rectifier circuit section include a first semiconductor switch, a second semiconductor switch connected in parallel with the first semiconductor switch, a first capacitor, and a first inductor, and the components of the second rectifier circuit section include a third semiconductor switch, a fourth semiconductor switch connected in parallel with the third semiconductor switch, a second capacitor, and a second inductor.

9. A power conversion device according to claim 8, characterized in that the planes of the midpoints of the first semiconductor switch and the fourth semiconductor switch, the planes of the midpoints of the second semiconductor switch and the third semiconductor switch, the planes of the midpoints of the first capacitor and the second capacitor, and the planes of the midpoints of the first inductor and the second inductor are arranged on equidistant lines between the first rectifier circuit section and the second rectifier circuit section.

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