Electronic device

Abstract

An electronic device (10) relates to energization switching of a rotary electric machine (80) having a plurality of winding sets (180, 280) and comprises a plurality of drive circuits (130, 230), a power supply circuit (40), and a smoothing circuit (45). The drive circuits (130, 230) have a plurality of switching elements (131 to 136, 231 to 236) and are provided for the respective winding sets (180, 280). The power supply circuit (40) is provided between a battery (5) and the drive circuits (130, 230). The smoothing circuit (45) has capacitors (451, 452) connected to the drive circuits (130, 230). The power supply circuit (40) and the plurality of drive circuits (130, 230) are connected to each other by a common power supply unit having a common potential. One electrode of each of the capacitors (451, 452) is connected to the common power supply unit.

Description

electronic equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-129864, filed on August 6, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to electronic devices.

[0003] Conventionally, electronic control units for controlling the driving of a motor have been known. For example, in Patent Document 1, an electronic control unit has two inverter systems and controls the supply of current to windings.

[0004] Patent No. 6597362

[0005] In Patent Document 1, a capacitor connected in parallel to a switching element is provided for each system. When a capacitor is provided for each system, there is a risk that the number of capacitors will increase in order to ensure the required capacity for each system. An object of the present disclosure is to provide an electronic device in which a smoothing circuit can be shared by multiple systems.

[0006] The electronic device disclosed herein is related to energization switching of a rotating electric machine having multiple winding sets, and includes multiple drive circuits, a power supply circuit, and a smoothing circuit. The drive circuits have multiple switching elements, one for each winding set. The power supply circuit is provided between a battery and the drive circuits. The smoothing circuit has a capacitor connected to the drive circuits.

[0007] The power supply circuit and the multiple drive circuits are connected by a common power supply section that has a common potential. One electrode of the capacitor is connected to the common power supply section. This allows the smoothing circuit to be shared by multiple systems.

[0008] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a schematic diagram showing an electric power steering apparatus according to a first embodiment, Fig. 2 is a cross-sectional view showing a drive unit according to the first embodiment, Fig. 3 is a cross-sectional view showing the drive unit according to the first embodiment, Fig. 4 is a circuit diagram of the drive unit according to the first embodiment, Fig. 5 is a circuit diagram explaining a common potential after a relay according to the first embodiment, Fig. 6 is a plan view showing a motor side of a circuit board according to the first embodiment, Fig. 7 is a plan view showing a cover side of a circuit board according to the first embodiment, Fig. 8 is a plan view showing the motor side of a circuit board according to the second embodiment, Fig. 9 is a plan view showing the motor side of a circuit board according to the third embodiment, Fig. 10 is a plan view showing the motor side of a circuit board according to the fourth embodiment, and Fig. 11 is a plan view showing a cover side of a circuit board according to the fourth embodiment.

[0009] First Embodiment An electronic device according to the present disclosure will now be described with reference to the drawings. In the following, in a plurality of embodiments, substantially the same components are designated by the same reference numerals, and description thereof will be omitted.

[0010] The first embodiment is shown in Figures 1 to 7. As shown in Figure 1, a drive unit 1 includes a motor 80 and an ECU 10 as an electronic device, and is applied to an electric power steering device 8 for assisting the steering operation of a vehicle. Figure 1 shows the overall configuration of a steering system 90 including the electric power steering device 8. The steering system 90 includes a steering wheel 91, which is a steering member, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, the electric power steering device 8, etc.

[0011] The steering wheel 91 is connected to a steering shaft 92. A torque sensor 94 that detects steering torque is provided on the steering shaft 92. The detected value of the torque sensor 94 is output to the corresponding microcomputer 50. A pinion gear 96 is provided at the tip of the steering shaft 92. The pinion gear 96 meshes with a rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like.

[0012] When the driver turns the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into linear motion of a rack shaft 97 by a pinion gear 96. A pair of wheels 98 are steered to an angle corresponding to the amount of displacement of the rack shaft 97.

[0013] The electric power steering device 8 includes the drive unit 1, and a reduction gear 89 as a power transmission unit that reduces the rotation of the motor 80 and transmits the reduced rotation to the steering shaft 92. The electric power steering device 8 of this embodiment is a so-called "column assist type," but it may also be a so-called "rack assist type" in which the rotation of the motor 80 is transmitted to a rack shaft 97.

[0014] 2 to 4, the motor 80 is a three-phase brushless motor that outputs part or all of the torque required for steering, is driven by power supplied from the battery 5, and rotates the reduction gear 89 forward and reverse.

[0015] The motor 80 has a first winding set 180 and a second winding set 280 as winding sets. Hereinafter, the combination of components related to the energization of the first winding set 180 will be referred to as the first system L1, and the combination of components related to the energization of the second winding set 280 will be referred to as the second system L2. Components in the first system L1 will be primarily numbered in the 100s, and components in the second system L2 will be primarily numbered in the 200s. Substantially similar components in systems L1 and L2 will be numbered so that the last two digits are the same, and explanations will be omitted where appropriate. Furthermore, where appropriate in the figures, components related to the first system L1 will be numbered with the suffix "1," and components related to the second system L2 will be numbered with the suffix "2."

[0016] As shown in Figures 2 and 3, the drive device 1 has the ECU 10 integrally provided on one axial side of the motor 80, which is a so-called "mechanically and electrically integrated" type, but the ECU 10 may be a separate unit. The ECU 10 is arranged coaxially with the axis Ax of the shaft 87 on the opposite side of the output shaft of the motor 80. The ECU 10 may also be provided on the output shaft side of the motor 80. By adopting a mechano-electrically integrated type, the ECU 10 and the motor 80 can be efficiently arranged in a vehicle with limited installation space. Hereinafter, when simply referring to the "axial direction" and "radial direction", it will be understood that this means the axial direction and radial direction of the motor 80.

[0017] The motor 80 includes a stator 84, a rotor 86, and a housing 83 that accommodates these components. The stator 84 is fixed to the housing 83, and has winding sets 180 and 280 wound therearound. The rotor 86 is disposed radially inside the stator 84 and is rotatable relative to the stator 84.

[0018] The shaft 87 is fitted into the rotor 86 and rotates integrally with the rotor 86. The shaft 87 is rotatably supported in the housing 83 by bearings 871 and 872. The end of the shaft 87 on the ECU 10 side protrudes from the housing 83 toward the ECU 10. A magnet 875 is provided on the end of the shaft 87 on the ECU 10 side as a detection target. The rotation angle sensor 57 is mounted on the circuit board 30 at a position opposite the magnet 875.

[0019] The housing 83 has a cylindrical case 831, a front end frame 832 provided on one side of the case 831, and a rear end frame 833 provided on the other side of the case 831. A lead wire insertion hole 834 is formed in the rear end frame 833. Lead wires 185, 285 connected to the respective phases of the winding sets 180, 280 are inserted through the lead wire insertion hole 834. The lead wires 185, 285 are taken out from the lead wire insertion hole 834 to the ECU 10 side. The lead wires 185, 285 are inserted through winding connection portions 121, 221 (see FIGS. 6 and 7), respectively, and connected to the circuit board 30 by soldering or the like.

[0020] The ECU 10 has a circuit board 30 and various electronic components mounted on the circuit board 30. The circuit board 30 is fixed to the surface of the rear frame end 833 opposite the motor 80 with fixing members 39 such as screws. The fixing members 39 are made of a conductive material. The surface of the circuit board 30 facing the motor 80 is called a motor surface 301, and the surface opposite the motor 80 is called a cover surface 302.

[0021] The cover 60 is formed in a generally cylindrical shape with a bottom, and fits onto the radially outer side of the rear frame end 833. The cover 60 is provided to cover the circuit board 30, and protects the ECU 10 from external impacts and prevents dust, water, and the like from entering the ECU 10. An opening 61 is provided on the side of the cover 60.

[0022] The connector 65 has a base portion 651 and a connector portion 655, and is formed in a generally L-shape in side view. The base portion 651 is fixed to the circuit board 30 with bolts or the like, and the end opposite the side from which the connector terminals 66 protrude is taken out radially outward from an opening 61 in the cover 60. The opening 61 fits onto the outside of a flange 652 provided on the outer wall of the base portion 651.

[0023] The connector portion 655 is formed on the output end side of the base portion 651, outside the cover 60. The opening of the connector portion 655 is open in the axial direction and is provided so that a harness (not shown) or the like can be inserted and removed. In this embodiment, the connector 65 is an integrated unit consisting of a power connector connected to the battery 5 for supplying power and a signal connector for transmitting signals, but these may be separate connectors. Furthermore, the number of connectors, the orientation of the opening, and the like can be set as desired.

[0024] The connector terminals 66 are inserted into the connector connection portions 35 (see FIGS. 6 and 7) from the motor surface 301 side, and are electrically connected to the circuit board 30. The connector terminals 66 include a power supply terminal and a ground terminal.

[0025] 4 and 5 show the circuit configuration of the drive device 1. The ECU 10 has inverters 130 and 230, a power supply circuit 40, a smoothing circuit 45, a microcomputer 50, pre-drivers 155 and 255, etc., and these electronic components are mounted on a substrate 30.

[0026] The first inverter 130 is provided corresponding to the first winding set 180, and the second inverter 230 is provided corresponding to the second winding set 280. The first winding set 180 has three-phase motor windings 181 to 183, and the second winding set 280 has three-phase motor windings 281 to 283. Power is supplied to the inverters 130 and 230 from a common battery 5. Hereinafter, in each wiring, the battery 5 side is referred to as the upstream side, and the motor 80 side is referred to as the downstream side.

[0027] The first inverter 130 is a three-phase inverter in which switching elements 131 to 136 are bridge-connected. The switching elements 131 to 136 are, for example, MOSFETs, but elements other than MOSFETs may also be used. The same applies to the switching elements 231 to 236 and reverse connection protection relays 141 and 241.

[0028] In the first inverter 130, switching elements 131 to 133 are connected to the high potential side, and switching elements 134 to 136 are connected to the low potential side. The connection point of the paired U-phase switching elements 131 and 134 is connected to one end of a U-phase motor winding 181, the connection point of the paired V-phase switching elements 132 and 135 is connected to one end of a V-phase motor winding 182, and the connection point of the paired W-phase switching elements 133 and 136 is connected to one end of a W-phase motor winding 183. The other ends of the motor windings 181 to 183 are wired.

[0029] The second inverter 230 is a three-phase inverter in which switching elements 231 to 236 are bridge-connected. In the second inverter 230, switching elements 231 to 233 are connected to the high potential side, and switching elements 234 to 236 are connected to the low potential side. The connection point of the paired U-phase switching elements 231 and 234 is connected to one end of a U-phase motor winding 281, the connection point of the paired V-phase switching elements 232 and 235 is connected to one end of a V-phase motor winding 282, and the connection point of the paired W-phase switching elements 233 and 236 is connected to one end of a W-phase motor winding 283. The other ends of the motor windings 281 to 283 are wired.

[0030] Current detection elements 137 to 139 are provided on the low potential sides of the switching elements 134 to 136, and detect the current flowing through each phase of the motor windings 181 to 183. Current detection elements 237 to 239 are provided on the low potential sides of the switching elements 234 to 236, and detect the current flowing through each phase of the motor windings 281 to 283. In this embodiment, the current detection elements 137 to 139 and 237 to 239 are shunt resistors, but elements other than shunt resistors, such as Hall ICs, may also be used.

[0031] The power supply circuit 40 is a circuit that supplies power from the battery 5 to the inverters 130, 230, and in this embodiment, the power supply circuit is a relay circuit. The power supply circuit 40 has reverse connection protection relays 141, 241. The reverse connection protection relays 141, 241 are provided so that the anode of the parasitic diode is on the battery 5 side and the cathode is on the inverters 130, 230 side. The provision of the reverse connection protection relays 141, 241 prevents reverse current from flowing if the battery 5 is mistakenly connected in reverse, thereby protecting the ECU 10. Note that in this embodiment, no power supply relay capable of cutting off the power supply from the battery 5 to the inverters 130, 230 is provided.

[0032] The downstream sides of the reverse connection protection relays 141, 241 are connected by a post-relay common potential pattern Pr (see FIG. 6), which is a wiring pattern of a common potential. In FIG. 4, the wiring corresponding to the post-relay common potential pattern Pr is numbered "Pr." The smoothing circuit 45 is connected between the post-relay common potential pattern Pr and ground. The smoothing circuit 45 includes a large capacitor 451 and a small capacitor 452.

[0033] In this embodiment, the large capacitor 451 is, for example, an electrolytic capacitor, and the small capacitor 452 is, for example, a ceramic capacitor. Here, "large" means that the component is relatively tall compared to the switching element, etc. Also, "small" means that the component is smaller in height than the large capacitor 451 and is equal to or shorter in height than the switching element, and is allowed to be tall enough not to interfere with heat dissipation from the switching element to the rear frame end 833. Using multiple types of capacitors makes it possible to smooth noise in different frequency bands.

[0034] The microcomputer 50 controls the driving of the inverters 130 and 230, thereby controlling the energization of the motor windings 181-183 and 281-283. The microcomputer 50 generates a control signal related to the driving of the first system and outputs it to the first pre-driver 155. The on / off operation of the switching elements 131-136 is controlled based on the drive signal from the first pre-driver 175. The microcomputer 50 generates a control signal related to the driving of the second system and outputs it to the second pre-driver 255. The on / off operation of the switching elements 231-236 is controlled based on the drive signal from the second pre-driver 255. Note that for convenience of illustration, in FIG. 4, the microcomputer 50 is divided into two blocks. Alternatively, a microcomputer may be provided for each system.

[0035] 6 and 7 show the board layout of the electronic components that make up the ECU 10. Fig. 6 shows the motor surface 301 of the board 30, and Fig. 7 shows the cover surface 302, with the cover surface 302 shown in a see-through state as viewed from the motor surface 301 side.

[0036] The substrate 30 is a laminated substrate having multiple wiring layers formed thereon. Wiring patterns such as a power supply pattern Pb, a post-relay common potential pattern Pr, and a ground pattern are formed on the wiring layer on the motor surface 301 side and the wiring layer on the cover surface 302 side, respectively. The corresponding wiring patterns on the motor surface 301 side and the cover surface 302 side are electrically connected by through holes TH. The through holes TH are hatched in the drawing.

[0037] The substrate 30 is formed with winding connection parts 121, 221, a connector connection part 35, and a motor fastening part 38. The winding connection parts 121, 221 are provided on the outer edge side of the substrate 30, symmetrically with respect to the substrate center line C. Lead wires 185, 285 are inserted into the winding connection parts 121, 221 and electrically connected by soldering or the like. This connects the substrate 30 and the winding sets 180, 280.

[0038] The connector connection portion 35 has a power supply terminal connection portion 351 that connects to the power supply terminal of the connector 65, and a ground terminal connection portion 352 that connects to the ground terminal. This connects the board 30 to the battery 5 and ground. The power supply terminal connection portion 351 and the ground terminal connection portion 352 are provided on the outer edge side of the board 30, adjacent to each other across the board center line C. The power supply terminal connection portion 351 is electrically connected to the power supply pattern Pb on the cover surface 302.

[0039] Fixing members 39 (see FIG. 2, etc.) are inserted into the motor fastening portions 38, and the fixing members 39 fix the circuit board 30 to the rear frame end 833. In this embodiment, there are four motor fastening portions 38, but the number and arrangement of the motor fastening portions 38 can be designed as desired.

[0040] In the substrate 30, the side of the connector connection portion 35 is a drive circuit region Rd through which a relatively large current flows, and the side opposite the connector connection portion 35 is a control circuit region Rc through which a relatively smaller current flows than in the drive circuit region Rd. The ground pattern in the drive circuit region Rd is the drive circuit ground, and the ground pattern in the control circuit region Rc is the control circuit ground. Since the drive circuit ground and the control circuit ground are at the same potential, the overlapping region can be used as the drive circuit ground and the control circuit ground.

[0041] The motor surface 301 is equipped with the switching elements 131 to 136, 231 to 236, current detection elements 137 to 139, 237 to 239, reverse connection protection relays 141, 241, a small capacitor 452, pre-drivers 155, 255, and a rotation angle sensor 57. The cover surface 302 is equipped with the large capacitor 451, the microcomputer 50, and the like.

[0042] On each mounting surface, the switching elements 131 to 136, 231 to 236, the current detection elements 137 to 139, 237 to 239, the reverse connection protection relays 141, 241, and the capacitors 451, 452 are mounted in the drive circuit region Rd. Also, on each mounting surface, the microcomputer 50 and the pre-drivers 155, 255 are mounted in the control circuit region Rc.

[0043] 6, the power supply pattern Pb and the post-relay common potential pattern Pr are formed in the drive circuit region Rd. The power supply pattern Pb is formed between the post-relay common potential pattern Pr and the connector connection portion 35. On the motor surface 301, the power supply pattern Pb, reverse connection protection relays 141, 241, the post-relay common potential pattern Pr, the small capacitor 452, and the pre-drivers 155, 255 are arranged in this order from the connector connection portion 35 side. In addition, an inverter 130 is provided on the winding connection portion 121 side of the post-relay common potential pattern Pr, and an inverter 230 is provided on the winding connection portion 221 side of the post-relay common potential pattern Pr.

[0044] The reverse connection protection relays 141, 241 have sources connected to the power supply pattern Pb and drains connected to a common post-relay common potential pattern Pr. Providing multiple reverse connection protection relays 141, 241 enables current distribution and redundancy. The reverse connection protection relays 141, 241 are arranged side by side on the power supply pattern Pb side of the post-relay common potential pattern Pr, with the reverse connection protection relay 141 being arranged on the first system area R1 side, and the reverse connection protection relay 241 being arranged on the second system area R2 side, as described below.

[0045] The switching elements 131 to 136, 231 to 236 and the reverse connection protection relays 141, 241 are formed in a generally rectangular shape in a plan view and are provided in a heat dissipating manner on the rear frame end 833 (see FIGS. 2 and 3). In this embodiment, the switching elements 131 to 136, 231 to 236 are each packaged individually, but multiple elements may be configured in a single package.

[0046] The switching elements 131 to 136 are mounted on one side of the post-relay common potential pattern Pr, and the switching elements 231 to 236 are mounted on the other side of the post-relay common potential pattern Pr. That is, in this embodiment, the drive circuits constituting the first system L1 and the drive circuits constituting the second system L2 are mounted on the board 30 in separate regions on both sides of the post-relay common potential pattern Pr. Hereinafter, the region where the switching elements 131 to 136 are mounted, which extends from the board center line C to the switching elements 134 to 136, will be referred to as the first system region R1, and the region where the switching elements 231 to 236 are mounted, which extends from the board center line C to the switching elements 234 to 236, will be referred to as the second system region R2.

[0047] In the first system region R1, the high-potential side switching elements 131 to 133 are on the post-relay common potential pattern Pr side and are arranged substantially parallel to the board center line C. The low-potential side switching elements 134 to 136 are on the outside of the switching elements 131 to 133 and are arranged substantially parallel to the board center line C.

[0048] In the second system region R2, the high-potential side switching elements 231 to 233 are on the post-relay common potential pattern Pr side and are arranged substantially parallel to the board center line C. The low-potential side switching elements 234 to 236 are on the outside of the switching elements 231 to 233 and are arranged substantially parallel to the board center line C.

[0049] The drains of the switching elements 131 to 133 and 231 to 233 are connected to a post-relay common potential pattern Pr formed across the substrate center line C. By connecting the high potential sides of the inverters 130 and 230 with the post-relay common potential pattern Pr, the coupling between the systems is strengthened.

[0050] The high-potential side switching elements 131-133, 231-233 are arranged so that their short sides are substantially parallel to the board center line C, while the low-potential side switching elements 134-136, 234-236 are arranged so that their long sides are substantially parallel to the board center line C. In other words, the high-potential side switching elements 131-133, 231-233 and the low-potential side switching elements 134-136, 234-236 are arranged in different orientations, rotated 90 degrees. The current detection elements 137-139, 237-239 are arranged adjacent to the short sides of the corresponding switching elements 134-136, 234-236. This allows the inverters 130, 230 to be arranged together on both sides of the post-relay common potential pattern Pr.

[0051] The small capacitor 452 is arranged along the side of the post-relay common potential pattern Pr opposite to the power supply pattern Pb, with one electrode connected to the post-relay common potential pattern Pr and the other electrode connected to ground. In this embodiment, there are two small capacitors 452, one arranged on the first system region R1 side and the other on the second system region R2 side.

[0052] The rotation angle sensor 57 is mounted approximately at the center of the motor surface 301 of the circuit board 30 so as to face the magnet 875. In this embodiment, the post-relay common potential pattern Pr is formed to extend to the center of the circuit board, and small capacitors 452 are arranged on both sides of the rotation angle sensor 57.

[0053] 7, on the cover surface 302, the power supply pattern Pb and the post-relay common potential pattern Pr are formed in the drive circuit region Rd, similar to the motor surface 301. On the cover surface 302, the power supply pattern Pb, the post-relay common potential pattern Pr, the large capacitor 451, and the microcomputer 50 are arranged in this order from the connector connection portion 35 side.

[0054] The large capacitor 451, like the small capacitor 452, is arranged on the cover surface 302 along the side of the post-relay common potential pattern Pr opposite the power supply pattern Pb. The positive electrode of the large capacitor 451 is connected to the post-relay common potential pattern Pr, and the negative electrode is connected to ground. In this embodiment, three large capacitors 451 are arranged side by side: one on the board center line C, one on the first system region R1 side, and one on the second system region R2 side. The capacitors 451 and 452 are arranged evenly in the first system region R1 and the second system region R2, but they do not necessarily have to be arranged evenly and may be arranged at any location that can be connected to the post-relay common potential pattern Pr.

[0055] In this embodiment, the downstream sides of the reverse connection protection relays 141, 241 are connected to a common post-relay potential pattern Pr that is common to the two systems. Furthermore, by connecting the capacitors 451, 452 to the common post-relay potential pattern Pr, the capacitors 451, 452 are shared by multiple systems. This reduces the number of capacitors required to ensure a desired capacity compared to providing a capacitor for each system. Furthermore, even if an abnormality occurs in one of the drive circuits and the circuit stops, all of the capacitors 451, 452 can be used in the normal system.

[0056] As described above, the ECU 10 of this embodiment is related to switching of energization of the motor 80 having a plurality of winding sets 180, 280, and includes a plurality of inverters 130, 230, a power supply circuit 40, and a smoothing circuit 45. The inverters 130, 230 have a plurality of switching elements 131-136, 231-236, each of which is provided for one winding set 180, 280.

[0057] The power supply circuit 40 is provided between the battery 5 and the inverters 130, 230. The power supply circuit of this embodiment is a relay circuit and includes reverse connection protection relays 141, 241. The smoothing circuit 45 includes capacitors 451, 452 connected to the inverters 130, 230.

[0058] The power supply circuit 40 and the inverters 130 and 230 are connected by a common power supply unit that has a common potential. In this embodiment, the common power supply unit is a post-relay common potential pattern Pr. One electrode of each of the capacitors 451 and 452 is connected to the post-relay common potential pattern Pr. This allows the smoothing circuit 45 to be appropriately connected. In particular, the capacitors 451 and 452 can be shared by multiple systems, reducing the number of capacitors used and contributing to miniaturization.

[0059] The drive device 1 includes a substrate 30 on which switching elements 131-136, 231-236, capacitors 451, 452, and a power supply circuit 40 are mounted, a connector connection portion 35 that connects to a connector 65 connected to a battery 5, and winding connection portions 121, 221 that connect to winding sets 180, 280 are provided. The power supply circuit 40 is provided on the connector connection portion 35 side of the post-relay common potential pattern Pr. The inverters 130, 230 are provided on the winding connection portions 121, 221 side of the post-relay common potential pattern Pr. Specifically, the inverter 130 is provided on the winding connection portion 121 side of the post-relay common potential pattern Pr, and the inverter 230 is provided on the winding connection portion 221 side of the post-relay common potential pattern Pr.

[0060] In other words, the inverters 130, 230 are arranged together for each system on the side of the post-relay common potential pattern Pr where the reverse connection protection relays 141, 241 are not provided. The post-relay common potential pattern Pr is formed so as to be drawn out from the board center line C toward the inverters 130, 230. This allows the components connected to the post-relay common potential pattern Pr to be arranged together.

[0061] The capacitors 451 and 452 are provided on the opposite side of the post-relay common potential pattern Pr from the connector connection portion 35. The capacitors include a large capacitor 451 that is a component that is taller than the switching elements 131 to 136 and 231 to 236. The multiple large capacitors 451 are arranged in the same straight line along the end of the post-relay common potential pattern Pr on the cover surface 302 side, which is a surface different from the motor surface 301 on which the switching elements 131 to 136 and 231 to 236 are mounted.

[0062] The capacitors 451 and 452 are arranged with one electrode facing the connector connection portion 35 and the other electrode facing the control circuit region Rc. The capacitors 451 and 452 are also arranged along the outer periphery of the post-relay common potential pattern Pr. This allows the capacitors 451 and 452 to be appropriately positioned.

[0063] The large capacitor 451 is disposed in the projected area of ​​the drive circuit area Rd including the inverters 130, 230. This allows the smoothing performance of the power supply provided by the large capacitor 451 to be improved. At least one large capacitor 451 is disposed on the board center line C, which is the center line that separates the areas for the inverters 130, 230. This equalizes the smoothing performance across multiple systems, improving shareability.

[0064] The capacitors include small capacitors 452 that are shorter in height than large capacitors 451. Small capacitors 452 are mounted on the motor surface 301, which is the same surface as the switching elements 131 to 136 and 231 to 236 of the circuit board 30. By using small capacitors 452 that are relatively small in height, they can be mounted on the same surface without interfering with the heat dissipation of the switching elements 131 to 136 and 231 to 236. This increases the degree of freedom in capacitor placement. Furthermore, by using different types of capacitors together, the frequency band in which noise can be smoothed can be expanded.

[0065] The control circuit region Rc, which is located on the opposite side of the connector connection portion 35 and separated from the post-relay common potential pattern Pr, is equipped with the microcomputer 50 and pre-drivers 155 and 255 that constitute the control circuit related to the current supply control of the winding sets 180 and 280. This makes it possible to arrange on a single board 30 both the drive circuit, through which a relatively large current flows, and the control circuit, which flows a smaller current than the drive circuit.

[0066] Second Embodiment A second embodiment is shown in Fig. 8. In the second embodiment, the power supply circuit 40 (see Fig. 4) includes a single reverse connection protection relay 43, which is provided on the board center line C. In other words, the reverse connection protection relay 43 is shared by two systems. This configuration also achieves the same effects as the above embodiment.

[0067] (Third Embodiment) A third embodiment is shown in FIG. 9. In the third embodiment, the rotation angle sensor 57 is not mounted on the circuit board 30. Three small capacitors 452 are mounted on the motor surface 301. Specifically, the small capacitors 452 are arranged along the side of the post-relay common potential pattern Pr opposite the power supply pattern Pb, and are arranged side by side on the circuit board center line C and on both sides of the circuit board center line C. Note that while FIG. 9 shows an example in which there is one reverse connection protection relay 43, multiple reverse connection protection relays may be used, as in the first embodiment. The same applies to the fourth embodiment. Even with this configuration, the same effects as the above embodiments can be achieved.

[0068] 10 and 11 show a fourth embodiment. In the fourth embodiment, the microcomputer 50, pre-drivers 155 and 255, and rotation angle sensor 57, which are control system components, are not mounted on the substrate 30 on which the switching elements 131 to 136 and 231 to 236 are mounted. In the third embodiment, the microcomputer 50, pre-drivers 155 and 255, and rotation angle sensor 57 are mounted on a control substrate (not shown) that is separate from the substrate 30, which is the drive substrate. Note that the arrangement of elements in the case of multiple substrates is arbitrary, such as mounting the rotation angle sensor 57 on the substrate 30 and mounting the microcomputer 50 and pre-drivers 155 and 255 on the control substrate.

[0069] In this embodiment, the power supply circuit 40 (see FIG. 4) has reverse connection protection relays 43 and 44, with the reverse connection protection relay 43 provided on the motor surface 301 and the reverse connection protection relay 44 provided on the cover surface 302. The reverse connection protection relays 43 and 44 are mounted on the power supply pattern Pb side of the post-relay common potential pattern Pr, on the board center line C. In the first embodiment as well, the reverse connection protection relays 141 and 241 may be arranged on both sides.

[0070] The small capacitors 452 are mounted on the motor surface 301 and the cover surface 302. As shown in Fig. 10, three small capacitors 452 are mounted on the motor surface 301. The detailed arrangement of the small capacitors 452 mounted on the motor surface 301 is the same as in the third embodiment.

[0071] As shown in FIG. 11 , two small capacitors 452 are mounted on the cover surface 302 side. The small capacitors 452 on the cover surface 302 side are located on the power supply pattern Pb side of the relay post-common potential pattern Pr, on both sides of the reverse connection protection relay 44. The small capacitors 452 are small in size and have a high degree of freedom in placement, so they can be placed anywhere along the periphery of the relay post-common potential pattern Pr depending on the required capacity, etc. As in the first embodiment, the drive board and the circuit board may be separated, or the small capacitor 452 may be placed on the cover surface 302 side. This configuration also achieves the same effects as the above embodiment.

[0072] In the embodiment, the ECU 10 corresponds to the “electronic device,” the inverters 130 and 230 correspond to the “drive circuit,” the microcomputer 50 and the pre-drivers 155 and 255 correspond to the “control circuit components,” the motor 80 corresponds to the “rotating electric machine,” and the post-relay common potential pattern Pr corresponds to the “common power supply unit.” Also, the motor surface 301 corresponds to the “surface on which the switching elements are mounted,” and the cover surface 302 corresponds to the “surface different from the surface on which the switching elements are mounted.”

[0073] Other Embodiments In the above embodiment, an example was described in which the number of large capacitors was three and the number of small capacitors was two, three, or five. In other embodiments, the number of capacitors may be different from that in the above embodiment. In the above embodiment, the large capacitors are electrolytic capacitors, and the small capacitors are ceramic capacitors. In other embodiments, capacitors other than electrolytic capacitors and ceramic capacitors may be used, and the number of types of capacitors may be one or three or more.

[0074] In the above embodiment, the capacitors are evenly arranged relative to the two drive circuits. In other embodiments, the capacitors may be unevenly arranged relative to the drive circuits as long as they are connected to the post-relay common potential pattern. In the above embodiment, the drive circuits are two systems. In other embodiments, the drive circuits may be three or more systems.

[0075] In the above embodiment, the power supply circuit is a relay circuit and includes a reverse polarity protection relay. In other embodiments, the relay element constituting the relay circuit is not limited to a reverse polarity protection relay, but may be, for example, a power relay. Furthermore, the power supply circuit may be a circuit that supplies power from the battery to the drive circuit, regardless of whether or not it includes a relay circuit. The power supply circuit may also be arranged unevenly with respect to the drive circuit, similar to the capacitor.

[0076] In the above embodiment, the electronic device is applied to an electric power steering device. In other embodiments, the electronic device may be applied to an in-vehicle device other than an electric power steering device, or to a device other than an in-vehicle device.

[0077] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0078] (Technical Idea 1) An electronic device for switching current flow in a rotating electric machine (80) having a plurality of winding sets (180, 280), comprising: a plurality of drive circuits (130, 230) each having a plurality of switching elements (131-136, 231-236), each provided for each of the winding sets; a power supply circuit (40) provided between a battery (5) and the drive circuits; and a smoothing circuit (45) having capacitors (451, 452) connected to the drive circuits, wherein the power supply circuit and the plurality of drive circuits are connected by a common power supply unit (Pr) at a common potential, and one electrode of the capacitor is connected to the common power supply unit. (Technical Idea 2) The electronic device according to Technical Idea 1, further comprising: a substrate (30) on which the switching element, the capacitor, and the power supply circuit are mounted, and on which a connector connection portion (35) that is a connection portion with a connector (65) that is connected to the battery, and a winding connection portion (121, 221) that is connected to the winding set are provided; the power supply circuit is provided on the connector connection portion side of the common power supply part; and the drive circuit is provided on the winding connection portion side of the common power supply part. (Technical Idea 3) The electronic device according to Technical Idea 2, further comprising: a capacitor provided on the side of the common power supply part opposite to the connector connection portion. (Technical Idea 4) The electronic device according to Technical Idea 2 or 3, further comprising: a large capacitor (451) that is a component taller than the switching element; and a plurality of the large capacitors are arranged along an edge of the common power supply part on a surface (302) different from a surface (301) on which the switching element is mounted. (Technical Idea 5) The electronic device according to Technical Idea 4, wherein the large capacitor is disposed in a projection area of ​​a drive circuit area including the drive circuit. (Technical Idea 6) The electronic device according to Technical Idea 4, wherein at least one of the large capacitors is disposed on a center line that divides an area for each of the drive circuits.(Technical Idea 7) The electronic device according to any one of Technical Ideas 4 to 6, wherein the capacitors include small capacitors (452) that are shorter in height than the large capacitors, and the small capacitors are mounted on the same surface of the substrate as the switching elements. (Technical Idea 8) The electronic device according to any one of Technical Ideas 2 to 7, wherein control circuit components (50, 155, 255) that constitute a control circuit related to controlling the supply of current to the winding set are mounted in a control circuit region opposite the connector connection portion and separated from the common power supply portion. (Technical Idea 9) The electronic device according to Technical Idea 8, wherein one electrode of the capacitor is arranged facing the connector connection portion and the other electrode facing the control circuit region. (Technical Idea 10) The electronic device according to any one of Technical Ideas 2 to 9, wherein the capacitors are arranged along the outer periphery of the common power supply portion.

[0079] As described above, the present disclosure is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the present disclosure.

[0080] The present disclosure has been described based on the embodiments. However, the present disclosure is not limited to the embodiments and structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. An electronic device for switching current flow in a rotating electrical machine (80) having a plurality of winding sets (180, 280), comprising: a plurality of drive circuits (130, 230) each having a plurality of switching elements (131-136, 231-236), each provided for each of the winding sets; a power supply circuit (40) provided between a battery (5) and the drive circuits; and a smoothing circuit (45) having capacitors (451, 452) connected to the drive circuits, wherein the power supply circuit and the plurality of drive circuits are connected by a common power supply unit (Pr) at a common potential, and one electrode of the capacitor is connected to the common power supply unit.

2. An electronic device as described in claim 1, comprising a substrate (30) on which the switching element, the capacitor, and the power supply circuit are mounted, and on which a connector connection portion (35) that is a connection portion with a connector (65) that is connected to the battery, and a winding connection portion (121, 221) that is connected to the winding set are provided, wherein the power supply circuit is provided on the connector connection portion side of the common power supply portion, and the drive circuit is provided on the winding connection portion side of the common power supply portion.

3. The electronic device according to claim 2, wherein the capacitor is provided on the opposite side of the common power supply section from the connector connection section.

4. An electronic device according to claim 2 or 3, wherein the capacitors include a large capacitor (451) that is a component taller than the switching element, and a plurality of the large capacitors are arranged along an edge of the common power supply unit on a surface (302) different from the surface (301) on which the switching element is mounted.

5. The electronic device according to claim 4, wherein the large capacitor is disposed in a projection area of ​​a driving circuit area including the driving circuit.

6. The electronic device according to claim 4, wherein at least one of said large capacitors is arranged on a center line that defines an area for each of said drive circuits.

7. The electronic device according to claim 4, wherein the capacitors include a small capacitor (452) having a height smaller than that of the large capacitor, and the small capacitor is mounted on the same side of the substrate as the switching element.

8. An electronic device as described in claim 2, wherein a control circuit area opposite the connector connection portion and separated from the common power supply portion is mounted with control circuit components (50, 155, 255) constituting a control circuit for controlling the supply of current to the winding group.

9. The electronic device according to claim 8, wherein the capacitor is arranged with one electrode facing the connector connection portion side and the other electrode facing the control circuit area side.

10. The electronic device according to claim 2, wherein the capacitors are arranged along the outer periphery of the common power supply portion.

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