ENERGY CONVERSION DEVICE

Abstract

Energy conversion device, comprising: - a power conversion circuit (120, 220) having a power element (121, 124) and configured to convert supplied electrical energy to output the converted energy; - a control circuit (170, 176, 270, 276) configured to control operation of the energy conversion circuit (120, 220); - a multi-layer substrate (30) having different layers, wherein power wiring patterns (P11, P12, P13, P21, P22, P23) of the power conversion circuit (120, 220) and a control wiring pattern (P18, P19) of the control circuit (170, 176, 270, 276) are arranged on the multi-layer substrate (30), wherein the power wiring patterns (P11, P12, P13, P21, P22, P23) are arranged in different layers of the multi-layer substrate (30); - a via (35a) extending over the power wiring patterns (P11, P12, P13, P21, P22, P23) in the different layers; and - a solid-formed conductive element (35, 352, 353, 354) provided in the via (35a) to electrically connect the respective power wiring patterns (P11, P12, P13, P21, P22, P23) to each other, wherein - the conductive element (35, 352, 353, 354) includes a conductive pad outer element (352); - the conductive pad-outside member (352) is arranged to be located outside a pad (30L) arranged on a surface layer (31, 32) of the multilayer substrate (30), as viewed from a direction perpendicular to a board surface of the multilayer substrate (30), and is connected to the pad (30L); - the energy conversion device further comprises an inner layer via (36a) connecting inner layers of the multilayer substrate (30) to one another; and - the inner layer via (36a) is connected to the conductive pad outer member (352) and arranged to overlap with the pad (30L) when viewed from a direction perpendicular to a board surface of the multilayer substrate (30).

Description

[0001] The present disclosure relates to a power conversion device for converting an input power to output the converted power.

[0002] JP 2017-143203 A discloses a power conversion device including an inverter circuit as a power conversion circuit and a control circuit for controlling the operation of the inverter circuit. A power wiring pattern included in the power conversion circuit and a control wiring pattern included in the control circuit are formed on a common substrate. This reduces the installation space of the substrate and downsizes the device.

[0003] In wiring (also called a power wiring pattern) of an inverter circuit, it may be advantageous to increase the thickness of the wiring to lower impedance and thus reduce heat generation caused by a large current flow. If the wiring is thickened, a wiring width and wiring pitch may increase due to a limitation in substrate manufacturing, so that fine wiring may not be formed. It may be inconvenient to wire a control circuit (a control wiring pattern) that requires a high-density layout. When both the power conversion circuit and the control circuit are provided on a common single substrate to achieve downsizing, it may be necessary to achieve both a reduction in impedance and downsizing (miniaturization) of the wiring.

[0004] US 2019 / 0 126 972 A1 relates to a structure of a load driving device that integrates an electric motor and a controller. A circuit board of the controller includes wiring layers provided on the front and back sides and inside thereof, and grounding layers provided inside thereof. Each wiring layer is divided into a first area in which a drive circuit is provided and a second area in which a control circuit is provided.A first ground layer having a first ground pattern for a circuit electrically connected to a wiring pattern of each wiring layer is divided into a third region overlapping with the first region in a thickness direction and in which the first ground pattern for a power system electrically connected to the drive circuit is provided, and a fourth region overlapping with the first region in the thickness direction and in which the first ground pattern for a control system electrically connected to the control circuit is provided.

[0005] From US 2015 / 0 189 734 A1, an electronic control unit and an electric power steering device with the electronic control unit are also known, and JP 2020- 188 659 A discloses an energy conversion device that converts energy and outputs the converted energy.

[0006] It is an object of the present disclosure to provide a power conversion device capable of realizing both a reduction in impedance and a reduction in wiring size.

[0007] The problem is solved by the subject matter of the main claim. Advantageous further developments are specified in the subclaims.

[0008] In the power conversion device according to the present invention, a multilayer substrate is used as a substrate on which both the power wiring pattern and the control wiring pattern are provided. The power wiring patterns arranged in different layers of the multilayer substrate are electrically connected to each other by solid-formed conductive elements (corresponding to solid vias) provided in the vias. In the case of solid vias, the electrical resistance between the layers can be reduced compared to the case of plating (corresponding to foil-like vias) formed in a film on the inner surfaces of the vias.

[0009] Therefore, according to the above disclosure, in which the power wiring patterns are arranged in the respective different layers of the multilayer substrate and the power wiring patterns are connected to each other via the vias, the power wiring patterns of the multiple layers can be designed to have an impedance equivalent to that of only one (single) layer of thick wiring. Since the via is a solid via, the impedance can be further reduced compared to the case of a foil-type via. In other words, the impedance can be lowered without thickening the power wiring pattern, and heat generation caused by a large current can be reduced.Furthermore, since the thickening of the power wiring pattern can be suppressed, the wiring width and wiring pitch of the control wiring pattern can be reduced and fine wiring can be enabled.

[0010] Objects, features, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings: Fig. 1 is a schematic diagram of a configuration illustrating a steering system according to a first embodiment; Fig. 2 a cross-sectional view of a steering system of Fig. 1 applied drive device; Fig. 3 a circuit diagram of the Fig. 2 shown drive device; Fig. 4 a bottom view of a drive device of Fig. 2 applied inverters viewed from one side of a motor; Fig. 5 a plan view of the drive device of Fig. 2 applied inverters viewed from an opposite side of the motor; Fig. 6 is a cross-sectional view of the inverter according to the first embodiment; Fig. 7 a view from the direction of an arrow VII in Fig. 6 recorded; Fig. 8 is a cross-sectional view of an inverter according to a second embodiment; Fig. 9 is a cross-sectional view of an inverter according to a third embodiment; and Fig. 10 a view from the direction of an arrow X in Fig. 9 recorded.

[0011] Several embodiments of the present disclosure will be described below with reference to the drawings. Corresponding components in each embodiment are denoted by the same reference numerals and may not be described repeatedly. While only a part of the configuration is described in each embodiment, the configuration of the other embodiments described above may be applied to other parts of the configuration. (First embodiment)

[0012] As in Fig. As shown in FIG. 1, a drive device 1 of the present embodiment includes an electric motor 80 and an electronic control unit (ECU) 10 as a power conversion device. The drive device 1 is applied to an electric power steering device (also referred to as EPS) 8 for assisting a steering operation of a vehicle. Fig. 1 shows an overall configuration of a steering system 90 with the EPS 8. The steering system 90 includes a steering wheel 91 as a steering element, a steering shaft 92, a gear transmission 96, a rack shaft 97, wheels 98, the EPS 8 and the like.

[0013] The steering wheel 91 is connected to the steering shaft 92. The steering shaft 92 is provided with a torque sensor 94 for detecting a steering torque. The torque sensor 94 has two torque detection units 941 and 942 provided for each system. The detection values of the torque detection units 941 and 942 are sent to the microcomputers 170 and 270, which are corresponding microcomputers (see Fig. 3). The gear transmission 96 is provided at a tip of the steering shaft 92. The gear transmission 96 is engaged with the rack shaft 97. The pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like.

[0014] When a driver operates or turns the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. A rotational movement of the steering shaft 92 is converted into a linear movement of the rack shaft 97 by the gear transmission 96. The pair of wheels 98 are steered at an angle corresponding to the displacement amount of the rack shaft 97.

[0015] The EPS 8 includes the drive device 1 and a reduction gear 89 as a power transmission section for reducing a rotational speed of the motor 80 and transmitting the rotational speed to the steering shaft 92. The steering shaft 92 is a drive target of the EPS 8.

[0016] As in the Fig. 2 and Fig. As shown in Figure 3, motor 80 is a brushless three-phase motor. Motor 80 provides some or all of the torque required for steering and is driven by energy supplied by batteries 199 and 299 to rotate reduction gear 89 forward and reverse.

[0017] The motor 80 includes a first winding 180 and a second winding 280 as a winding set. The windings 180 and 280 have equivalent electrical characteristics and are wound on a common stator 840 with electrical angles offset by 30 degrees. In response to the above configuration, the windings 180 and 280 are controlled to be excited with a phase current whose phase φ is shifted by 30 degrees.

[0018] A combination of configurations related to power supply control of the first winding 180 is referred to as a first system L1. A combination of configurations related to power supply control of the second winding 280 is referred to as a second system L2. The configuration of the first system L1 is numbered mainly in the 100s, the configuration of the second system L2 is numbered mainly in the 200s, and the configurations that are substantially similar to each other in the systems L1 and L2 are numbered such that the last two digits are the same, and a description of these configurations is omitted where appropriate.

[0019] As in Fig. 2, the drive device 1 has the ECU 10 integrated on one side of the motor 80 in the axial direction, which is a so-called "electromechanically integrated type" or referred to as an engine / electricity integral type. The ECU 10 is provided on the other side of the reduction gear 89 with respect to the motor 80. The ECU 10 is arranged coaxially with a center line Ax of a rotating shaft 870. With the electromechanically integrated type, the ECU 10 and the motor 80 can be efficiently installed in a vehicle with limited installation space. When simply referring to "axial direction" or "radial direction," as applicable, it means the axial direction or the radial direction of the motor 80.

[0020] The motor 80 includes a stator 840, a rotor 860, a rotating shaft 870, and a housing 830 that houses the stator 840, the rotor 860, the rotating shaft 870, and the like. The stator 840 is fixed to the housing 830, and the windings 180 and 280 are wound around the stator 840. The rotor 860 is disposed radially inside the stator 840 and is rotatable relative to the stator 840.

[0021] The rotation shaft 870 is fitted into the rotor 860 and rotates integrally with the rotor 860. The rotation shaft 870 is rotatably supported in the housing 830 via bearings 835 and 836. One end of the rotation shaft 870 on the ECU 10 side protrudes from the housing 830 toward the ECU 10 side. A magnet 875 as a detection target is provided at the end of the rotation shaft 870 on the ECU 10 side.

[0022] The housing 830 includes a cylindrical housing 834, a rear frame end 837 at one end of the housing 834, and a front frame end 838 at the other end of the housing 834.

[0023] An opening 837a is provided in the rear frame end 837 through which the rotary shaft 870 is inserted and arranged. A lead wire insertion hole 839 is provided in the rear frame end 837. A lead wire 285 connected to each phase of the windings 180 and 280 is inserted into the lead wire insertion hole 839. The lead wire 285 is led out of the lead wire insertion hole 839 to the ECU 10. The lead wire 285 is connected through motor wire connecting portions 186 and 286 (see Fig. 4 and Fig. 5) and connected to a substrate 30 by solder or the like.

[0024] The ECU 10 includes the substrate 30 and various electronic components mounted on the substrate 30. The substrate 30 is fixed to the substrate by screws or bolts inserted via substrate connecting portions 155 and 255 (see Fig. 2) attached to a surface of the rear frame end 837 opposite the motor 80. The screws or bolts 259 are constructed of a conductive material. A surface of the substrate 30 on the side of the motor 80 is defined as a motor surface 301, and the surface of the substrate 30 on the side opposite the motor 80 is defined as a cover surface 302. The cover 460 is formed in a substantially cylindrical shape with a bottom and fits radially outwardly toward the rear frame end 837. The cover 460 is provided to cover the substrate 30 and protect the ECU 10 from external influences and prevent dust, water, or the like from entering the ECU 10. An opening 461 is provided on a side surface of the cover 460.

[0025] The connector 350 has connector terminals such as a first power supply terminal, a first ground terminal, a first signal terminal, a second power supply terminal, a second ground terminal, and a second signal terminal. The first power supply terminal, the first ground terminal, and the first signal terminal are inserted from the motor surface 301 side of the substrate 30 and electrically connected to a first power supply terminal connecting portion 151, a first ground terminal connecting portion 152, and a first signal terminal connecting portion 153 (see Fig. 4 and Fig. 5). The second power supply terminal, the second ground terminal, and the second signal terminal are inserted from the motor surface 301 side of the substrate 30 and electrically connected to the second power supply terminal connecting portion 251, the second ground terminal connecting portion 252, and the second signal terminal connecting portion 253 (see Fig. 4 and Fig. 5).

[0026] Fig. 3 shows a circuit arrangement of the drive device 1. The ECU 10 includes a first inverter 120, first motor relays 127 to 129, first power supply relays 131 and 132, a first capacitor 134, and a first coil 135 provided corresponding to the first winding 180. The ECU 10 further includes a second inverter 220, second motor relays 227 to 229, second power supply relays 231 and 232, a second capacitor 234, and a second coil 235 provided corresponding to the second winding 280.

[0027] The first inverter 120 and the like of the first system L1 are supplied with electric power from the first battery 199. The second inverter 220 and the like of the second system L2 are supplied with electric power from the second battery 299. In the present embodiment, the ground is also separated by the first system L1 and the second system L2. The first microcomputer 170 controls the power supply to the first winding 180, and the second microcomputer 270 controls the power supply to the second winding 280. In other words, in the present embodiment, the first system L1 and the second system L2 are provided independently of each other in a fully redundant configuration.

[0028] The first inverter 120 is a three-phase inverter, and the first switching elements 121 to 126 are bridge-connected. The switching elements 121 to 123 are connected to a high-potential side to form an upper arm H. The switching elements 124 to 126 are connected to a low-potential side to form a lower arm L. A node of the paired U-phase switching elements 121 and 124 is connected to one end of a first U-phase coil 181. A node of the paired V-phase switching elements 122 and 125 is connected to one end of a first V-phase coil 182. A node of the paired W-phase switching elements 123 and 126 is connected to one end of a first W-phase coil 183. The other ends of the coils 181 to 183 are connected together.Shunt resistors 137 to 139, which are current detecting elements for detecting currents flowing in the coils 181 to 183, are provided on the low potential side of the switching elements 124 to 126, respectively.

[0029] The second inverter 220 has the same configuration as the first inverter 120. In other words, the switching elements 221 to 223 are connected to a high-potential side to form an upper arm H. The switching elements 224 to 226 are connected to a low-potential side to form a lower arm L. The output points of the upper- and lower-arm circuits of the respective UVW phases are connected to the respective UVW-phase coils. Shunt resistors 237 to 239, which are current detection elements for detecting currents flowing in the coils 281 to 283, are provided on the low-potential side of the switching elements 224 to 226.

[0030] The first motor relays 127 to 129 are located between the first inverter 120 and the first winding 180 and are provided so that the first inverter 120 and the first winding 180 can be disconnected and connected to each other. The U-phase motor relay 127 is provided between the node of the switching elements 121 and 124 and the U-phase coil 181. The V-phase motor relay 128 is provided between the node of the switching elements 122 and 125 and the V-phase coil 182. The W-phase motor relay 129 is provided between the node of the switching elements 123 and 126 and the W-phase coil 183. The second motor relays 227 to 229 have the same configuration as the first motor relays 127 to 129 and are provided for the respective UVW phases.

[0031] The first power supply relays 131 and 132 are connected in series such that the orientations of the parasitic diodes are opposite, and are provided between the first battery 199 and the first inverter 120. The second power supply relays 231 and 232 are connected in series such that the orientations of the parasitic diodes are opposite, and are provided between the second battery 299 and the second inverter 220. This prevents current from flowing in the reverse direction and protects the ECU 10 when the batteries 199 and 299 are incorrectly connected in the reverse direction.

[0032] The driver preamplifier 176 outputs a drive signal based on a control signal from the first microcomputer 170. The first switching elements 121 to 126, the first motor relays 127 to 129, and the first power supply relays 131 and 132 are controlled to be turned on and off in accordance with the drive signal. The driver preamplifier 276 of the second system L2 functions in the same manner as the driver preamplifier 176 of the first system L1. In other words, the second switching elements 221 to 226, the second motor relays 227 to 229, and the second power supply relays 231 and 232 are turned on and off by the driver preamplifier 276. To avoid complicating the drawings, control lines to the motor relays and the power supply relays are shown in Fig. 3 omitted.

[0033] The first capacitor 134 is connected in parallel with the first inverter 120, and the second capacitor 234 is connected in parallel with the second inverter 220. The capacitors 134 and 234 are formed, for example, from aluminum electrolytic capacitors. The first coil 135 is provided between the first battery 199 and the first power supply relay 131, and the second coil 235 is provided between the second battery 299 and the second power supply relay 231.

[0034] The first capacitor 134 and the first coil 135, as well as the second capacitor 234 and the second coil 235, each form a filter circuit. These filter circuits reduce noise transmitted from other devices sharing batteries 199 and 299. Furthermore, the filter circuits reduce noise transmitted from the drive device 1 to the other devices sharing batteries 199 and 299. Furthermore, the capacitors 134 and 234 store electrical charges, thereby helping to supply power to the inverters 120 and 220.

[0035] An inter-system ground connection capacitor 41 connects a first system ground G1 and a second system ground G2. A first electromechanical connection capacitor 142 connects the first system ground G1 and the housing 830 of the motor 80. A second electromechanical connection capacitor 242 connects the second system ground G2 and the housing 830. The capacitors 41, 142, and 242 are constructed, for example, from ceramic capacitors.

[0036] The motor surface 301 of the substrate 30 is in Fig. 4, and the cover surface 302 is shown in Fig. 5. For the sake of description, the arrangement of the cover surface 302 is reversed, and the first system L1 is shown on a left side, and the second system L2 is shown on a right side of a paper plane.

[0037] As in Fig. As shown in Fig. 4, the switching elements 121 to 126 and 221 to 226, as well as the shunt resistors 137 to 139 and 237 to 239, are mounted on the motor surface 301 of the substrate 30. The motor relays 127 to 129 and 227 to 229, as well as the power supply relays 131, 132, 231, and 232, are mounted on the motor surface 301. Furthermore, integrated circuits 175 and 275, and a rotation angle sensor 29 (corresponding to a sensor element) are mounted on the motor surface 301. The integrated IC 175 includes the driver pre-circuit 176, and the integrated IC 275 includes the driver pre-circuit 276. The rotation angle sensor 29 detects a change in a magnetic field by the magnet 875 provided on the rotation shaft 870 and outputs a detection signal corresponding to a rotation angle of the rotation shaft 870.

[0038] As in Fig. 5, the capacitors 134 and 234 and the coils 135 and 235 are mounted on the cover surface 302 of the substrate 30. Furthermore, the inter-system ground connection capacitor 41, the electromechanical connection capacitors 142 and 242 (see Fig. 3) and the microcomputers 170 and 270 are mounted on the cover surface 302.

[0039] As in the Fig. 4 and Fig. As shown in Figure 5, the substrate 30 is electrically separated into two parts by a slot 305. Parts related to the first system L1 are mounted in one area on the motor surface 301 and the cover surface 302. Parts related to the second system L2 are mounted in the other area on the motor surface 301 and the cover surface 302.

[0040] The rotation angle sensor 29 is arranged in a region of the substrate 30 facing the opening 837a of the rear frame end 837 (corresponding to an opening-opposing region). The rotation angle sensor 29 is mounted on the motor surface 301 across the slot 305. The inter-system ground connection capacitor 41 is mounted on the cover surface 302 across the slot 305 and connects the first system ground G1 and the second system ground G2.

[0041] The first electromechanical connecting capacitor 142 connects the ground pattern P13 of the first system L1 (see Fig. 5) and the housing connection pattern 157. The second electromechanical connection capacitor 242 connects the ground pattern P23 of the second system L2 (see Fig. 5) and the housing connection pattern 257. The housing 830 is connected to the vehicle ground. In other words, the capacitors 41, 142, and 242 are all capacitors for connecting between the grounds. Furthermore, it is conceivable that the inter-system ground connection capacitor 41 establishes a connection between the grounds of the power supply circuits of the systems L1 and L2.

[0042] In the present embodiment, the drive device 1 is applied to the EPS 8, and a large current is supplied in a short time, so switching noise and ringing noise may be generated. The above-described noise N may be generated mainly in a circuit of the ECU 10, and the generated noise may propagate to the vehicle side via the connector 350 and the motor 80. Therefore, the ground of the substrate 30 and the case 830 are electrically connected to each other by means of screws and bolts to form a noise feedback path from the motor 80 to the ECU 10. As a result, noise generated in the circuit of the ECU 10 is fed back to a noise source and the propagation of the noise to the vehicle side is prevented.

[0043] As in Fig. As shown in Figure 6, a multilayer substrate is used as the substrate 30 of the present embodiment. A plurality of wiring layers, a plurality of insulating layers 34, surface resist layers 37, vias, and the like are formed in the substrate 30. Conductive wirings are provided in the wiring layers. The insulating layer 34 having an electrically insulating property is interposed between the adjacent wiring layers.

[0044] The wiring layers include surface layers 31 and 32 and inner layers 33. The surface layers 31 and 32 are the outermost layers of all wiring layers. The inner layers 33 are layers located within the entire wiring layers. In an example of Fig. 6, the inner layers 33 comprise four layers (multiple layers). The surface layers 31 and 32 are covered with surface resist layers 37. The surface resist layer 37 covering the surface layer 31 forms the motor surface 301. The surface resist layer 37 covering the surface layer 32 forms the cover surface 302.

[0045] The vias include through holes (not shown) and inner vias 35a and 36a. The through holes are shaped to penetrate all of the surface layers 31, 32 and the inner layers 33 (all wiring layers). The inner vias 35a are shaped to extend over one of the surface layers 31 and 32 and an inner layer 33 adjacent to the one surface layer. The inner via 36a is shaped to extend over all of the inner layers 33 except the surface layers 31 and 32. The inner vias 35a are formed by laser processing, and the inner via 36a is formed by drilling.

[0046] Inner surfaces of the through holes and the inner via 36a are subjected to plating 36 as conductive elements. The plating 36 is cylindrically shaped to create a space inside. A non-conductive element (not shown) is "packaged" inside the cylinder of the inner via 36a. In contrast, a conductive element is "buried" in each of the inner vias 35a. The conductive element has a solid shape and is referred to as a solid via 35. The solid vias 35 and the plating 36 electrically connect wiring patterns formed in any wiring layers. Specific examples of a material of the plating 36 and the solid vias 35 include copper.

[0047] A part of the wiring pattern formed in the wiring layer functions as a wiring for connecting the Fig. 3. The wiring patterns include power wiring patterns included in the inverters 120 and 220, and control wiring patterns P18 and P19 included in the control circuit. The power wiring patterns include the ground patterns P13 and P23 and the power supply patterns P11, P12, P21, and P22. In addition, the power wiring patterns in Fig. 6 and the like. The output patterns P14a and P14b are wiring patterns for connecting the upper arm H, the lower arm L, and the motor relay 127. These patterns are present in the first system L1 and the second system L2, respectively. (Details on the mass pattern)

[0048] The ground patterns P13 and P23 form part of the grounds G1 and G2 and are electrically connected to the ground terminal connecting portions 152 and 252. The ground patterns P13 and P23 are electrically connected to the electromechanical connection capacitors 142 and 242 and the inter-system ground connection capacitor 41 in the surface layer 32 on the cover surface 302 side. The respective ground patterns P13 and P23 are electrically connected to low-potential side terminals of the capacitors 134 and 234 and the shunt resistors 137 to 139 and 237 to 239 in the surface layer 31 on the motor surface 301 side.

[0049] The Fig. 4 and Fig. The ground patterns P13 and P23 shown in Figure 5 are parts of the ground patterns provided in all of the wiring layers, and the other ground patterns are omitted from the drawings. The ground patterns P13 and P23 are provided on the inner layer 33.

[0050] The power wiring patterns of the same systems provided in different wiring layers are connected to each other by the multiple solid vias 35 and the plating 36. For example, in the Fig. 4 and Fig. 5, the ground pattern of the surface layer 31 (not shown) connected to the low-potential side terminals of the shunt resistors 137 to 239, and the ground patterns P13 and P23 of the inner layers 33 are connected to each other by the plurality of solid vias 35 and the plating 36.

[0051] As in Fig. 6, the ground patterns P13b of the inner layers 33 and the ground pattern P13a provided on the surface layer 32 are connected to each other by the plurality of solid vias 35. The power supply patterns P12a of the inner layers 33 and the power supply pattern P12b on the surface layer 32 are connected to each other via the plurality of solid vias 35. The solid vias 35 are arranged so that they do not overlap with lands 30L formed on the surface layer 32 when viewed from a direction perpendicular to the board surface. In other words, the solid vias 35 are arranged so that they are located outside the lands 30L in a direction perpendicular to a board surface.The solid vias 35 described above are referred to as solid pad-outside vias 352 (corresponding to conductive pad-outside elements). The direction perpendicular to the board surface corresponds to a direction perpendicular to the board surface of a substrate.

[0052] The plating 36 of the inner via 36a, which is connected to the solid pad outer vias 352 and connects the inner layers 33 to each other, is also referred to as an inner layer via. The inner layer via, which is connected to the solid pad outer via 352 among the inner layer vias, is arranged to overlap the pads 30L when viewed from the direction perpendicular to the board surface (see Fig. 6).

[0053] The ground pattern P13 of the first system L1 is shaped so that, when viewed from the direction perpendicular to the plate surface of the substrate 30 (corresponding to a plate surface normal), it includes the entirety of the power supply relays 131 and 132, the switching elements 121 to 126, and the shunt resistors 137 to 139. Similarly, the ground pattern P23 of the second system L2 is shaped so that, when viewed from the direction perpendicular to the plate surface, it includes the entirety of the power supply relays 231 and 232, the switching elements 221 to 226, and the shunt resistors 237 to 239. In other words, all of the components such as the power supply relays 231 and 232, the switching elements 221 to 226, and the shunt resistors 237 to 239 are overlapped with the ground patterns P13 and P23 when viewed from the direction perpendicular to the plate surface.

[0054] The coils 135 and 235 and the capacitors 134 and 234 provided on the cover surface 302 are also completely overlapped with the ground patterns P13 and P23 when viewed from the direction perpendicular to the board surface. The group of components overlapped with the ground patterns P13 and P23 among the components provided on the surface layers 31 and 32 is referred to as ground pattern overlap components. The solid vias 35 connected to the ground pattern overlap component are also overlapped with the ground patterns P13 and P23. For example, as shown in the Fig. 4 and Fig. 5, the solid vias 35 connected to the shunt resistors 237 to 239 and the solid vias 35 connected to the power supply relay 131 also completely overlap with the ground patterns P13 and P23 when viewed from the direction perpendicular to the board surface. (Details on the energy supply pattern)

[0055] The power supply patterns P11 to P22 are connected to the high-potential side of the inverters 120 and 220 for supplying electric power. The power supply patterns P11 to P22 of the respective systems are electrically connected to the high-potential side terminals of the capacitors 134 and 234 and the power supply relays 132 and 232 in the surface layer 31 on the motor surface 301 side. The power supply patterns P11 to P22 of the respective systems are electrically connected to the high-potential side terminals of the switching elements 121 to 123 and 221 to 223.

[0056] The Fig. 4 and Fig. The power supply patterns P11 to P22 shown in Figure 5 are part of the power supply patterns provided in each of all the wiring layers; other power supply patterns are omitted from the drawings. The power supply patterns P11 and P21 shown are provided on the surface layer 32 on the cover surface 302 side. The power supply patterns P12 and P22 shown are provided on the surface layer 31 on the motor surface 301 side.

[0057] The power supply patterns of the same systems provided in different wiring layers are connected to each other by the multiple solid vias 35 and the plating 36. For example, in the Fig. 4 and Fig. 5, the power supply patterns P12 and P22 of the surface layer 31 to which the first power supply relays 131 and 231 are connected and the power supply patterns P11 and P21 of the surface layer 32 are connected to each other via the plurality of solid vias 35 and the plating 36.

[0058] The power supply pattern P11 of the first system L1 provided on the surface layer 32 is shaped to include the entirety of the power supply terminal connecting portion 151 and the coil 135 when viewed from the direction perpendicular to the board surface. The power supply pattern P21 of the second system L2 provided on the surface layer 32 is similarly shaped to include the entirety of the power supply terminal connecting portion 251 and the coil 235 when viewed from the direction perpendicular to the board surface. In other words, the entirety of the power supply terminal connecting portions 151 and 251 and the coils 135 and 235 overlap with the power supply patterns P11 and P21 when viewed from the direction perpendicular to the board surface.

[0059] The power supply pattern P12 of the first system L1 provided on the surface layer 31 is shaped to include the entirety of the switching elements 121 to 123 and the power supply relays 131 and 132 when viewed from the direction perpendicular to the board surface. Similarly, the power supply pattern P22 of the second system L2 provided on the surface layer 31 is shaped to include the entirety of the switching elements 221 to 223 and the power supply relays 231 and 232 when viewed from the direction perpendicular to the board surface. In other words, the switching elements 121 to 223 and the power supply relays 131 to 232 are completely overlapped with the power supply patterns P12 and P22 when viewed from the direction perpendicular to the board surface.

[0060] Of the components on the surface layer 31, the component group overlapped with the power supply patterns P12 and P22 is referred to as power supply pattern overlap components. The solid vias 35 connected to the power supply pattern overlap components are also overlapped with the power supply patterns P12 and P22. For example, as shown in the Fig. 4 and Fig. 5, the solid vias 35 connected to the power supply relays 131 and 231 also overlap with the power supply patterns P11 to P22 when viewed from the direction perpendicular to the board surface.

[0061] The ground pattern P13 of the first system L1 is shaped such that, when viewed from the direction perpendicular to the plate surface, it encompasses the entirety of the power supply patterns P11 and P12 of the first system L1. Similarly, the ground pattern P23 of the second system L2 is shaped such that, when viewed from the direction perpendicular to the plate surface, it encompasses the entirety of the power supply patterns P21 and P22 of the second system L2. In other words, the entirety of the power supply patterns P11 to P22 overlap with the ground patterns P13 and P23 when viewed from the direction perpendicular to the plate surface.

[0062] The rotation angle sensor 29 is arranged in a region of the substrate 30 facing the opening 837a through which the rotation shaft 870 is inserted and arranged. This region corresponds to an opening-opposing region. The power supply pattern and the ground pattern are arranged at positions that do not overlap with the rotation angle sensor 29 when viewed from the direction perpendicular to the plate surface. (Arrangement of solid vias)

[0063] The plurality of solid vias 35 include those located outside the switching elements 121 to 126 and 221 to 226 when viewed from the direction perpendicular to the board surface. The above-described solid vias 35 are referred to as the external solid vias 351. The external solid vias 351 correspond to external conductive elements. The external solid vias 351 connect the power wiring patterns of the surface layers 31 and 32 on which the switching elements are mounted and the power wiring patterns of the internal layer 33 located adjacent to the power wiring patterns.

[0064] In the example of Fig. 6, the output pattern P14a formed on the surface layer 33 on which the switching elements 121 and 124 are mounted and the output pattern P14b formed on the adjacent inner layer 33 are connected to each other via the external solid vias 351. The switching elements 121 and 124 correspond to energy and power elements, respectively.

[0065] As in Fig. 7, the switching elements 121 and 124 have a rectangular shape when viewed from the direction perpendicular to the board surface. The plurality of solid external vias 351 are aligned side by side along the above rectangular outline. The plurality of solid external vias 351 are arranged in a ring shape to surround the switching elements 121 and 124. In the example of Fig. 7, the external solid vias 351 are arranged in a row in a rectangular shape around the switching elements 121 and 124, and the external solid vias 351 are arranged in a row in a rectangular shape farther outward than the external solid vias 351. In other words, two rows of external solid vias 351 are provided around the switching elements 121 and 124.

[0066] A distance between the solid outer via 351 of a first row and the switching elements 121 and 124 is smaller than the maximum diameter of the solid outer vias 351. A distance between the solid outer via 351 of the first row and the solid outer via 351 of a second row is smaller than the maximum diameter of the solid outer vias 351. The output patterns P14a and P14b connected by the solid outer via 351 connect the switching element 121 of the upper arm and the switching element 124 of the lower arm.

[0067] When wiring the power wiring patterns P11 to P23, as well as P12a, P12b, P13a, P13b, P14a, and P14b, it may be desirable to increase the thickness of the wiring to lower the impedance and thus reduce heat generation caused by a large current. However, if the wiring is thickened, a wiring width and wiring pitch may become large due to a limitation in substrate manufacturing, so that fine wiring cannot be formed. For this reason, it may be unsuitable to wire the control wiring patterns P12a and P12b, which require high-density layouts. Consequently, when both the power conversion circuit and the control circuit are provided on the same substrate to achieve downsizing, the power wiring pattern and the control wiring pattern are mixed on the same substrate.Therefore, both a reduction in impedance and a reduction in wiring size may be necessary.

[0068] According to the present embodiment, a multi-layer substrate is used as the substrate 30, on which the power wiring patterns P11 to P23, P12a, P12b, P13a, P13b, P14a, and P14b, as well as the control wiring patterns P18 and P19, are provided. The power wiring patterns arranged in different layers of the multi-layer substrate are electrically connected to each other by solid conductive elements provided in the via holes 35a. The solid via holes 35 correspond to one solid conductive element.

[0069] This makes it possible to provide the power wiring pattern of multiple layers with an impedance equivalent to the impedance of only one (single) layer of thick wiring. Furthermore, since the vias are formed as the solid vias 35, the impedance can be further reduced compared to the case of the foil-type via. In other words, the impedance can be lowered without thickening the power wiring pattern, and heat generation caused by a large current flowing through the power wiring pattern can be reduced. Furthermore, since thickening of the power wiring pattern can be prevented, the wiring widths and wiring pitches of the control wiring patterns P18 and P19 can be reduced, so that fine wiring can be achieved.

[0070] Furthermore, according to the present embodiment, the switching elements 121 and 124 (corresponding to power elements) included in the power conversion circuit are mounted on the surface layers 31 and 32 of the multilayer substrate. The solid vias 35 include the plurality of external solid vias 351 (corresponding to external conductive elements) that are located outside the power element when viewed from the direction perpendicular to the board surface and that are arranged side by side along the outline of the power element. According to the above configuration, since the external solid vias 351 are positioned in a path of the current flowing through the power element, the impedance reduction effect can be achieved.

[0071] Furthermore, according to the present embodiment, the plurality of external solid vias 351 are arranged in a ring shape to surround the power element. For this reason, the impedance reduction effect is brought about. Moreover, heat generated in the power element can be instantly dissipated from the power element to the external solid vias 351 and stored. In the case of the EPS 8, for example, a large current flows instantly, so that the power element can instantly reach a high temperature. The heat is instantly stored in the external solid vias 351, so that the power element can be prevented from reaching a high temperature. Even if the heat radiation element is provided, the amount of heat that can be instantly transferred from the power element to the heat radiation element is limited.Also in the above case, the solid external vias 351 are caused to act as a heat radiation buffer, so that a temperature rise of the power element can be prevented.

[0072] Furthermore, in the present embodiment, the electric power conversion circuit supplies electric power to the motor 80 of the EPS 8 to generate a steering force of the vehicle. Since the motor 80 for the EPS 8 has a characteristic of instantaneously flowing a large current, the impedance reduction effect is achieved.

[0073] Furthermore, in the present embodiment, the inner-layer vias connected to the solid-land-outside vias 352 (corresponding to conductive-land-outside elements) among the inner-layer vias connecting the inner layers 33 of the multi-layer substrate are arranged so as not to overlap with the lands 30L when viewed from the direction perpendicular to the board surface. According to the above configuration, since the solid-land vias 35 can be arranged outside the lands 30L, the possibility of laser processing heat damaging the lands 30L can be reduced when the solid-land vias 35 are formed with a laser. (Second embodiment)

[0074] In the first embodiment, the solid vias 35 include the solid pad-outside vias 352 (corresponding to conductive pad-outside elements) arranged so as not to overlap with the pads 30L when viewed from the direction perpendicular to the board surface. In the present embodiment, as shown in Fig. 8, solid land inner vias 354 (corresponding to conductive land inner elements) are arranged such that they overlap with lands 30L when viewed from the direction perpendicular to the board surface. Fig. The pads 30L shown in Figure 8 are formed on a surface layer 32 of a substrate 30 and connected to a capacitor 134. The pads 30L are shaped such that they extend in a direction perpendicular to the plane of Fig. 8, and the plurality of solid land inner vias 354 are arranged in the direction perpendicular to the sheet plane along the shape of the lands 30L.

[0075] According to the above configuration, the solid land-inside vias 354 are arranged to overlap with the lands 30L when viewed from the direction perpendicular to the board surface. For this reason, compared to the case where the solid vias 35 are arranged around the lands 30L, a space for arranging the wiring patterns and components around the lands 30L can be easily secured. (Third embodiment)

[0076] In the present embodiment, an ECU 10 as shown in Fig. 9, a metallic heat radiating element 850 and a gel 851 are shown. The gel 851 corresponds to a deformation heat transfer material. The heat radiating element 850 may be an air-cooled heat exchanger that exchanges heat with air around a substrate 30, or a water-cooled heat exchanger that exchanges heat with circulating cooling water.

[0077] The gel 851 is interposed in a deformed state between a surface of a power element or the substrate 30 and the heat radiation member 850. The gel 851 is brought into close contact with the power element, the substrate 30, and the heat radiation member 850. Although the above deformation is plastic deformation, a deformation heat transfer material that elastically deforms and is brought into close contact with the above elements may be used instead of the gel 851. When the gel 851 is brought into contact with the above elements in this way, the heat of the power element and the substrate 30 is transferred to the heat radiation member 850 through the gel 851 and radiated to the air and cooling water.

[0078] Solid vias 35 include solid vias 353 arranged to overlap a portion of the substrate 30 with which the gel 851 is brought into close contact, when viewed from the direction perpendicular to the board surface. The solid vias 35 described above are referred to as solid heat-dissipating vias 353. External solid vias 351 arranged around the power element also function as solid heat-dissipating vias. The solid vias 35 correspond to conductive elements. The solid heat-dissipating vias 353 correspond to conductive heat-dissipating elements.

[0079] In the examples of Fig. 9 and Fig. 10, an area of the substrate 30 between the two switching elements 121 and 124 corresponds to an area with which the gel 851 is brought into close contact. More than half of the area is occupied by the massive heat-dissipating vias 353.

[0080] According to the present embodiment, the plurality of massive heat-radiating vias 353, as described above, are provided in the region with which the gel 851 is brought into close contact. These massive heat-radiating vias 353 are superior in thermal conductivity to the insulating layer 34. For this reason, according to the present embodiment, the heat from the power wiring patterns located in the inner layers 33, such as the initial pattern P14b, is easily transferred to the gel 851 through the massive heat-radiating vias 353. This can improve the heat radiation from the power wiring patterns located in the inner layer 33 and, hence, the heat radiation from the substrate 30. (Other embodiments)

[0081] Although several embodiments of the present disclosure are described above, not only the combinations of the configurations explicitly shown in the description of each embodiment, but also the configurations of several embodiments are partially combinable even if the combination is not explicitly shown, especially when the combination does not cause any problems. Unspecified combinations of the configurations described in the several embodiments and modification examples are also disclosed in the following description.

[0082] In each of the above embodiments, the solid vias 35 connect the power wiring patterns arranged in the adjacent layers, but may also connect the power wiring patterns in the distant layers. The external solid vias 351, all of the land-outside solid vias 352, the heat-dissipating solid vias 353, and the land-inside solid vias 354 according to the above embodiments may be formed in the substrate 30. At least one of these solid vias may be provided. Alternatively, the solid vias 35 that do not correspond to any of these solid vias may be provided, and the other solid vias may be eliminated.

[0083] In the embodiment of Fig. 8, both the power supply pattern and the ground pattern are arranged at positions that do not overlap with the rotation angle sensor 29 when viewed from the direction perpendicular to the plate surface. In contrast, at least one of the power supply pattern and the ground pattern may overlap with the rotation angle sensor 29.

[0084] In the example of Fig. 2, the opening 837a is provided in the rear frame end 837, and the rotating shaft 870 is inserted through the opening 837a. The magnet 875 attached to the tip of the rotating shaft 870 is exposed through the opening 837a and faces the rotation angle sensor 29. On the other hand, the opening 837a may be eliminated, and a part of the rear frame end 837 may be inserted between the rotation angle sensor 29 and the magnet 875. However, even in this case, it is desirable to arrange the rotation angle sensor 29 on the center line Ax of the rotating shaft 870.

[0085] In the embodiment of Fig. 1, the power conversion device includes the motor 80 for the EPS 8 as a power supply target. On the other hand, another motor, such as a motor for driving the vehicle, may be a power supply target. In the first embodiment, a circuit constituting the inverters 120 and 220 is applied to the power conversion circuit provided on the substrate 30, but a boosting circuit may also be applied.

[0086] In the embodiment of Fig. 3, the components constituting the first system L1 and the components constituting the second system L2 in the drive device 1 are mounted on only one (single) substrate 30. In contrast, these components may be mounted separately on the multiple substrates. The components constituting the first system L1 include the first inverter 120, the first motor relays 127 to 129, the first power supply relays 131 and 132, the first capacitor 134, the first coil 135, and the like. The components constituting the second system L2 include the second inverter 220, the second motor relays 227 to 229, the second power supply relays 231 and 232, the second capacitor 234, and the second coil 235.

[0087] In the embodiment of Fig. 3, the switching elements 121 to 126, the motor relays 127 to 129, and the power supply relays 131, 132 are all MOSFETs. However, an IGBT, a thyristor, or the like may be used. The power supply relays 131 and 132 may be mechanical relays. The second system L2, like the first system L1, may include an IGBT, a thyristor, or a mechanical relay instead of the MOSFET.

[0088] Although the Fig. 3 has an inter-system ground connection capacitor 41, the inter-system ground connection capacitor 41 may be eliminated (omitted). Although the Fig.3 includes electromechanical connection capacitors 142 and 242, these electromechanical connection capacitors 142 and 242 may be eliminated. In this case, the ground pattern for each system or the power supply pattern for each system may be omitted from being divided and arranged in each region separated by the slot 305.

[0089] The inter-system ground connection capacitor 41 is mounted on the substrate 30 and electrically connects the ground of each system. This makes it possible to form a path for returning the noise propagated to the other system side via the motor windings 180 and 280 and the like to the host system on the substrate 30. The electromechanical connection capacitors 142 and 242 connect the case connection patterns 156, 157, 256, and 257 to the ground pattern of the substrate 30. This makes it possible to form a low-impedance path for returning the noise propagated to the motor 80 side to the ECU 10 including the inverters 120 and 220. This can reduce the propagation of noise to the outside of the drive device 1, such as a vehicle.

[0090] In the first embodiment, the power conversion circuit and the control circuit for controlling the operation of the power conversion circuit are provided on a common substrate 30. The power conversion circuit is constituted by the inverters 120 and 220, and the control circuit is constituted by the microcomputers 170 and 270 and the driver pre-stages 176 and 276. Both the power wiring pattern of the power conversion circuit and the control wiring pattern (not shown) of the control circuit are formed on the substrate 30. Specific examples of the power wiring patterns include the ground patterns P13 and P23, the power supply patterns P11 and P21, and the like. Alternatively, the power conversion circuit and the control circuit may be provided on separate substrates.However, the substrate 30 on which the solid vias 35 are provided has at least a part of the power wiring patterns and at least a part of the control wiring patterns.

[0091] In the first embodiment, a control circuit is provided for each of the power conversion circuits of the two systems, and the control circuit is also configured in two systems. In contrast, a control circuit may be common to each of the power conversion circuits of the two systems, and the control circuit may be configured as only one (single) system. Furthermore, all of the circuits, including the power conversion circuit, may be configured as one system.

[0092] The inverter 120 corresponds to a power conversion device. The inverter 220 corresponds to a power conversion device. The microcomputers 170 and 270, the driver pre-circuit 176, and the driver pre-circuit 276 correspond to a control circuit. The substrate 30 corresponds to a multilayer substrate. The solid via 35 corresponds to a conductive element. The solid outer via 351 corresponds to an outer conductive element. The solid heat radiation via 353 corresponds to a conductive heat radiation element. The solid pad inner via 354 corresponds to an inner pad conductive element. The inner via 35a corresponds to a via. Each of the switching elements 121 and 124 corresponds to a power element.

[0093] Although various embodiments, configurations, and aspects of a power conversion device of the present disclosure are described above by way of example, the embodiments, configurations, and aspects of the present disclosure are not limited to those described above. For example, embodiments, configurations, and aspects resulting from a suitable combination of technical elements disclosed in various embodiments, configurations, and aspects also fall within the scope of the embodiments, configurations, and aspects of the present disclosure.

Claims

[1] Energy conversion device, comprising: - a power conversion circuit (120, 220) having a power element (121, 124) and configured to convert supplied electrical energy to output the converted energy; - a control circuit (170, 176, 270, 276) configured to control operation of the energy conversion circuit (120, 220); - a multi-layer substrate (30) having different layers, wherein power wiring patterns (P11, P12, P13, P21, P22, P23) of the power conversion circuit (120, 220) and a control wiring pattern (P18, P19) of the control circuit (170, 176, 270, 276) are arranged on the multi-layer substrate (30), wherein the power wiring patterns (P11, P12, P13, P21, P22, P23) are arranged in different layers of the multi-layer substrate (30); - a via (35a) extending over the power wiring patterns (P11, P12, P13, P21, P22, P23) in the different layers; and - a solid-formed conductive element (35, 352, 353, 354) provided in the via (35a) to electrically connect the respective power wiring patterns (P11, P12, P13, P21, P22, P23) to each other, wherein - the conductive element (35, 352, 353, 354) includes a conductive pad outer element (352); - the conductive pad-outside member (352) is arranged to be located outside a pad (30L) arranged on a surface layer (31, 32) of the multilayer substrate (30), as viewed from a direction perpendicular to a board surface of the multilayer substrate (30), and is connected to the pad (30L); - the energy conversion device further comprises an inner layer via (36a) connecting inner layers of the multilayer substrate (30) to one another; and - the inner layer via (36a) is connected to the conductive pad outer member (352) and arranged to overlap with the pad (30L) when viewed from a direction perpendicular to a board surface of the multilayer substrate (30). [2] Energy conversion device according to claim 1, wherein - the power element (121, 124) is mounted on a surface layer (31, 32) of the multilayer substrate (30); and - the conductive element (35, 352, 353, 354) includes a plurality of conductive outer elements (351) which are arranged outside the power element (121, 124) and along a contour of the power element (121, 124) when viewed from a direction perpendicular to a plate surface of the multilayer substrate (30). [3] Energy conversion device according to claim 2, wherein the conductive outer elements (351) are arranged in a ring shape, surrounding the power element (121, 124). [4] Energy conversion device according to one of claims 1 to 3, wherein - the conductive element (35, 352, 353, 354) includes a conductive pad inner element (354); and - the conductive pad-inner member (354) is arranged to overlap with the pad (30L) provided on a surface layer (31, 32) of the multi-layer substrate (30) as viewed from a direction perpendicular to a board surface of the multi-layer substrate (30) and is connected to the pad (30L). [5] Energy conversion device according to one of claims 1 to 4, further comprising: - a deformation heat transfer material (851) which is deformed and adheres to the power element (121, 124) of the energy conversion circuit (120, 220), and is deformed and adheres to the multilayer substrate (30), wherein - the conductive member (35, 352, 353, 354) includes a conductive heat radiation member (353) arranged to overlap with a portion of the multilayer substrate (30) to which the deformation heat transfer material (851) adheres, as viewed from a direction perpendicular to a plate surface of the multilayer substrate (30). [6] The power conversion device according to any one of claims 1 to 5, wherein the power conversion circuit (120, 220) supplies electric power to a motor (80) that exerts a steering force of the vehicle.

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