Electronic control unit and electric power steering unit

Abstract

Electronic control device (9) controlling a motor (8), comprising: a variety of power modules (11a, 11b) configured to drive the motor (8), wherein the power terminals (32) of at least one power module (11a) from the plurality of power modules (11a, 11b) are arranged at positions that are close to each other and face the power terminals (32) of the other power module (11b), wherein the power terminals (32) of one power module (11a) and the power terminals (32) of the other power module (11b) have opposite polarity to each other, where: the multitude of power modules (11a, 11b) are arranged on the same level, and the power connections (32) of one power module (11a) are drawn from an end area (311) of a main unit (31) of one power module (11a) facing the other power module (11b); and where: the protruding lengths, in the width direction of the module main unit (31), of the positive and negative electrode side terminals of the power terminals (32) differ from each other.

Description

TECHNICAL AREA

[0001] The present invention relates to an electronic control device for a motor and a device that uses this control device. STATE OF THE ART

[0002] An electric power steering device is known to be a redundant power steering device in which two power module systems operating as inverters (for example, in patent documents 1 to 3) are mounted.

[0003] In a power steering device described in patent document 1, power modules are arranged, with the power modules facing each other radially in the direction of the power steering device. In this arrangement, the power modules are intentionally separated from each other to dissipate heat generated during operation of the power steering device. Therefore, the connections of these two power modules are also naturally separate.

[0004] In a power steering device of patent document 2, a plurality of power modules are arranged in the same plane. A positive electrode-side power terminal of one power module is separated from a negative electrode-side power terminal of another power module.

[0005] In a power steering device described in patent document 3, a plurality of sector-shaped (or fan-shaped) power modules are arranged in the same plane. As in patent document 2, the positive electrode-side power terminal of one power module is separated from the negative electrode-side power terminal of another power module. Patent document 4 discloses a power supply device. Patent document 5 discloses an inverter device. Patent document 6 discloses a control device for a motor unit. Patent document 7 discloses a power steering device. DOCUMENT LIST PATENT DOCUMENT Patent document 1: Unexamined Japanese patent application with publication number 2013-207969 (JP 2013 - 207 969 A) Patent document 2: Unexamined Japanese patent application with publication number 2011-229229 (JP 2011 229 - 229 A) Patent document 3: Unexamined Japanese patent application with publication number 2013-151206 (JP 2013 - 151 206 A) Patent document 4: JP 2013 - 192 403 A Patent document 5: JP 2005 - 192 296 A Patent document 6: US 2014 / 0 077 638 A1 Patent document 7: JP 5 373 949 B1 SUMMARY OF THE INVENTION

[0006] Since, in prior art redundant power steering devices, the positive electrode-side power terminal of one power module and the negative electrode-side power terminal of the other power module are separated, the inductance of a power circuit in the power steering device increases, switching losses increase, and the noise level also becomes high. This further results in a poor voltage utilization ratio (or poor voltage utilization coefficient) of battery power.

[0007] The present invention was conceived with regard to the above-mentioned technical problems. It is therefore an object of the present invention to reduce the inductance of the power circuit, to lower the switching loss and the noise level, and to improve the voltage utilization ratio of the battery power in the redundant electronic control device.

[0008] The present invention is defined by an electronic control device and an electric power steering device according to the independent claims. The electronic control device, which controls a motor, comprises: a plurality of power modules configured to drive the motor, and the power terminals of at least one power module from the plurality of power modules are arranged in positions close to each other and facing the power terminals of the other power module, wherein the power terminals of one power module and the power terminals of the other power module have opposite polarity to each other.

[0009] Furthermore, the electric power steering device comprises: a plurality of power modules configured to drive a motor, wherein power terminals of at least one power module from the plurality of power modules are arranged in positions close to each other and facing power terminals of the other power module, wherein the power terminals of one power module and the power terminals of the other power module have opposite polarity to each other.

[0010] According to the present invention, the power terminals of one power module are arranged in positions that are close to each other and face the power terminals of the other power module, wherein the power terminals of one power module and the power terminals of the other power module have opposite polarities to each other. Therefore, the magnetic field generated in each power module during the operation of the electronic control device is canceled out and the inductance of the power circuit is reduced.

[0011] Since the inductance of the power circuit in the redundant electronic control device is reduced according to the present invention, the switching loss is reduced, the noise level is reduced, and the voltage utilization ratio is improved. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a longitudinal cross-section of an electronic control device according to a first embodiment of the present invention. Fig. Figure 2 shows a perspective view of the electronic control device. Fig. Figure 3 shows a perspective view illustrating an arrangement of power modules in the electronic control device. Fig. Figure 4 shows a top view illustrating an arrangement of the power modules in the electronic control device. Fig. Figure 5 shows a top view illustrating a rear side of a control board used in the electronic control device. Fig. Figure 6 shows a perspective view of an electric power steering device which uses the electronic control device. EXAMPLES OF IMPLEMENTING THE INVENTION

[0012] Exemplary embodiments of the present invention are described below with reference to the drawings.

[0013] One in Fig. Figure 1 of the electronic control device 9 of the present invention shows an example of an electronic control device used on an electric power steering device 6 which is in Fig. 6 is provided in a steering mechanism.

[0014] The in Fig. The steering mechanism 1 shown in Figure 6 is equipped with a pinion (not shown) at the lower end of a steering shaft 2, which is connected to a steering wheel (not shown). This pinion engages with a rack (not shown) that extends to the right and left within a vehicle body. A tie rod 3 for steering a front wheel to the left and right is connected to both ends of the rack. The rack is housed in a rack housing 4. A rubber boot 5 is provided between the rack housing 4 and each tie rod 3. The steering mechanism 1 is also equipped with the electric power steering device 6 to provide torque assistance when turning the steering wheel.

[0015] The electric power steering device 6 comprises a torque sensor 7, which detects the direction of rotation and the steering torque of the steering shaft 2. An electric motor 8 of the rack provides a steering assistance force via a gearbox 10 based on a detected value from the torque sensor 7. The device also includes an electronic control unit 9, which controls the electric motor 8. The electric motor 8 is connected to the gearbox 10 by means of three sections of an outer circumference on an output shaft side of the electric motor 8, which is connected to the gearbox 10 by bolts (not shown). The electronic control unit 9 is located on a side opposite the output shaft side of the electric motor 8.

[0016] The electric motor 8 is a so-called two-winding motor (double-winding motor) in which three-phase windings from two systems are wound inside a stator of the electric motor 8, and the three-phase terminals of each system are brought to the outside. For simplicity, these windings are referred to as the a-winding and the b-winding. By applying essentially the same three-phase current to the a-winding and the b-winding, the two systems generate essentially the same torque and essentially the same back electromotive force in any given rotational state and any given load state, so that the electric motor 8 is controlled as if two motors with the same characteristics were performing the same operation.

[0017] As in Fig. As shown in Figure 1, the electronic control device has 9 power modules 11 of the two systems, and thus has functions of parallel redundant inverters that drive the two-winding motor.

[0018] That is, the electronic control device 9 has a pair of power modules 11a, 11b that drive the electric motor 8, a power board 12 to which these power modules 11a, 11b are electrically connected, and a control board 13 to which the power modules 11a, 11b are electrically connected.

[0019] We in Fig. 1 and Fig. As shown in Figure 2, the power board 12 is essentially concentrically (coaxially) attached to a frame end 14 on sockets 15, which are provided at the edge areas of the frame end 14, by means of fastening metals 20.

[0020] Wires connected to power terminals 32 of the power modules 11a, 11b are configured on the power board 12 such that smoothing capacitors are charged by a current supplied from an external power source and the current of the smoothing capacitors is applied as drive current to the three-phase windings of the two systems of the electric motor 8 via the power modules 11a, 11b. As shown in Fig. As shown in Figure 2, smoothing capacitors 16, connectors 17 and 18, and an inductor (not shown), etc., are optionally mounted on the power board 12. The smoothing capacitors 16 also serve as an element of a filter circuit for reducing noise coming from other devices using the same power source. Connector 17, for example, is a connector to which a wiring harness for supplying power from the power source is connected. Connector 18, for example, is a connector that is connected to a wiring harness for receiving control signals from a vehicle's main control unit, or to a wiring harness for sending control signals from the control board 13 and sensor signals, etc., to the main control unit.

[0021] The control board 13 is a circuit board for controlling the operation of the power modules 11a and 11b, and the control board 13 is electrically connected to the power board 12. As shown in Fig. As shown in Figure 1, the control board 13 is housed inside the frame end 14, which is attached to one end of a motor housing (not shown) of the Fig. The control board 13 is mounted on the electric motor 8 shown in Figure 6. It is essentially concentrically (coaxially) attached to the frame end 14 on bases 19 provided in the frame end 14 by means of fastening metals 20.

[0022] A rotary angle sensor 21, a known customer-specific IC (not shown), a microcomputer (not shown), and a driver (not shown), etc., may be mounted on the control board 13. As shown in Fig. As shown in Figure 5, the rotary angle sensor 21 is essentially located at the center of a surface of the control board 13 which faces the electric motor 8.

[0023] The control board 13 is further equipped with a circuit that sends the control signals to inverter main circuit elements, which are elements of the power modules 11a, 11b, more precisely MOSFETs (metal oxide semiconductor field-effect transistors). In this way, the control board 13 is configured such that the power modules 11a, 11b are electrically connected to the control board 13 and a control current flows to the power modules 11a, 11b to control the electric motor 8.

[0024] The power modules 11a, 11b each have a main unit 31 in which an inverter circuit, which drives the electric motor 8, is located, as shown in Fig. 3 shown, assembled.

[0025] Three pairs of power connections 32pua, 32nua, 32pva, 32nva, 32pwa and 32nwa are drawn from one longitudinal side end region 311 of the main unit 31 of the power module 11a. In addition, control connections 33 and three-phase motor connections 34ua, 34va and 34wa are drawn from the other longitudinal side end region 312 of the main unit 31 of the power module 11a.

[0026] Three pairs of power connections 32pub, 32nub, 32pvb, 32nvb, 32pwb and 32nwb are drawn from one longitudinal side end region 311 of the main unit 31 of the power module 11b. In addition, control connections 33 and three-phase motor connections 34ub, 34vb and 34wb are drawn from the other longitudinal side end region 312 of the main unit 31 of the power module 11b.

[0027] As in Fig. As shown in Figure 3, each of the power connections 32pua, 32nua, 32pva, 32nva, 32pwa, 32nwa and 32pub, 32nub, 32pvb, 32nvb, 32pwb, 32nwb protrudes from one longitudinal side end region 311 of the main unit 31 in the width direction of the main unit 31, and is bent vertically at a midpoint of the power connection and extends upwards.

[0028] The negative electrode side power terminals 32nua, 32nva, 32nwa and 32nub, 32nvb, 32nwb are designed in particular such that their projecting lengths in the width direction are each shorter than those of the positive electrode side power terminals 32pua, 32pva, 32pwa and 32pub, 32pvb, 32pwb.

[0029] As in Fig. 1 and Fig. As shown in Figure 3, each of the motor terminals 34ua, 34va, 34wa and 34ub, 34vb, 34wb protrudes from the other longitudinal side end region 312 of the main unit 31 in the width direction of the main unit 31, and is bent vertically at a midpoint of the motor terminal and extends upwards.

[0030] Each of the control ports 33 protrudes from the other longitudinal side end region 312 of the main unit 31 in the width direction of the main unit 31 and is bent vertically at a midpoint of the control port, and extends upwards.

[0031] As in Fig. As shown in Figure 1, the power modules 11a, 11b are arranged parallel to each other on the same plane on bases 141, which are provided at one end area of ​​the frame end 14.

[0032] In this arrangement, as in Fig. 1 and Fig. Figure 4 shows the positive electrode-side power terminals 32pua, 32pva and 32pwa, which are drawn from the longitudinal side end region 311 of the main unit 31 of the power module 11a, positioned close to the negative electrode-side power terminals 32nub, 32nvb and 32nwb, which are drawn from the one longitudinal side end region 311 of the main unit 31 of the power module 11b that faces the one longitudinal side end region 311 of the power module 11a, wherein these 32pua, 32pva, 32pwa and 32nub, 32nvb, 32nwb are each facing each other.

[0033] On the other hand, the negative electrode-side power terminals 32nua, 32nva and 32nwa, which are drawn from one longitudinal side end region 311 of the main unit 31 of the power module 11a, are positioned close to the positive electrode-side power terminals 32pub, 32pvb and 32pwb, which are drawn from one longitudinal side end region 311 of the main unit 31 of the power module 11b, which faces one longitudinal side end region 311 of the power module 11a, with these 32nua, 32nva, 32nwa and 32pub, 32pvb, 32pwb each facing each other.

[0034] Each power connection 32 and each motor connection 34 of the power modules 11a, 11b are electrically connected to the power board 12 by soldering and are connected to it as shown in Fig. 1 and Fig. 2 shown, attached.

[0035] The motor terminals 34 may have been connected to the electric motor 8's leads in mid-air (i.e., in a floating connection) during the assembly of the electronic control device. Thus, the motor terminals 34 are not necessarily connected to the power board 12. Furthermore, depending on the circuit arrangements of the power board 12 and control board 13, the motor terminals 34 may have been connected to the control board 13.

[0036] On the other hand, the control connections 33 of the power modules 11a, 11b are inserted into the frame end 14 through connection insertion openings 140, which are formed at the end area of ​​the frame end 14, and are connected to and attached to the control board 13 by soldering.

[0037] The power board 12 and the control board 13 are electrically connected by conductor frames 22, which electrically connect a control circuit of the control board 13 and a power circuit of the power board 12. The conductor frames 22 are also soldered to and attached to the power board 12 and the control board 13.

[0038] Furthermore, three-phase busbars 23 are electrically connected to the power board 12 by soldering. The busbars 23 are inserted into the frame end 14 through the openings 140 and are connected to the Fig. The electric motor shown in section 6 is electrically connected to section 8.

[0039] The power modules 11a, 11b, the power board 12, the control board 13 and the frame end 14 described above are in a Fig. The housing 24 shown in Figure 1 is housed within the housing 24. The housing 24 has an opening 241 on its cover plate 240, through which the connectors 17 and 18 are inserted.

[0040] The operation of the electric power steering device 6 is described with reference to Fig. 1 and Fig. 6 described.

[0041] When the steering shaft 2 is rotated in any direction by the steering wheel, the direction of rotation and the steering torque of the steering shaft 2 are detected by the torque sensor 7. The control circuit of the control board 13 calculates a drive actuation value of the electric motor 8 based on the detected values ​​of the torque sensor 7 and the rotation angle sensor 21. The power modules 11a and 11b drive the electric motor 8 according to a control signal based on a value of the calculated drive actuation value. The control is implemented such that the same current flows to the corresponding three-phase terminals of the power module 11a and the power module 11b at any given time.With this arrangement, the windings of the two systems of the electric motor 8 generate an essentially equal torque, and the output shaft of the electric motor 8 rotates to drive and rotate the steering shaft 2 in the same direction as the steering wheel's direction of rotation. This rotation of the output shaft of the electric motor 8 is transmitted to the rack (not shown) via the pinion (not shown) and the gear 10.

[0042] In the present embodiment, as in Fig. Figure 4 shows, in particular the positive electrode-side power terminals 32pua, 32pva and 32pwa of the power module 11a are positioned close to the negative electrode-side power terminals 32nub, 32nvb and 32nwb of the power module 11b, with these 32pua, 32pva, 32pwa and 32nub, 32nvb, 32nwb facing each other. Furthermore, the negative electrode-side power terminals 32pua, 32nva and 32nwa of the power module 11a are positioned close to the positive electrode-side power terminals 32pub, 32pvb and 32pwb of the power module 11b, with these 32nua, 32nva, 32nwa and 32pub, 32pvb, 32pwb facing each other.

[0043] Since the power terminals of the dual-system power modules 11a and 11b, which have opposite polarities, face each other as described above, in-phase currents of these two power modules 11a and 11b are canceled out or offset. This leads to an enhancement of the effect of canceling out the influence of a magnetic field generated in the power modules 11a and 11b, thereby reducing the inductance of the power circuitry of the power board 12. As a result, the switching loss is reduced, the noise level is lowered, and the voltage utilization ratio of the battery power is improved.

[0044] This means that in the case of an electronic control device with a single power module, there is a limit to the reduction in inductance that can be achieved by arranging the positive electrode-side power terminal and the negative electrode-side power terminal close together.

[0045] In contrast, in the present embodiment, where the electronic control device has the dual-system power modules, the power terminal of one power module is positioned close to the power terminal of the other power module with opposite polarity in a surface-to-surface configuration, thereby significantly reducing the inductance of the power circuit compared to the electronic control device with the single power module.

[0046] During the explanation of the electronic control device using the single power module as an example, the following was experimentally determined: if the distance between a pair of copper power terminals p and n is, for example, 0.9 mm, the inductance value is approximately 11 nH. If the distance between the pair of copper power terminals p and n is also 0.5 mm, the inductance value is approximately 9 nH.

[0047] In contrast, in the case of the electronic control device with the dual-system power modules, the following was experimentally determined, for example: if the distance between the power terminals of opposite polarity from one pair of copper power terminals (0.9 mm spacing between two terminals) of one power module and one pair of copper power terminals (0.9 mm spacing between two terminals) of the other power module is, for example, 20 mm, as in the present embodiment, the inductance value is approximately 11 nH. Additionally, if the distance is 0.5 mm, the inductance value is less than 6 nH.

[0048] By arranging the positive electrode-side power terminals of one power module of the dual-system power modules in positions close to the negative electrode-side power terminals of the other power module, so that these are facing the negative electrode-side power terminals of the other power module, it is possible, as described above, to reduce the value of the inductance by approximately 60% compared to the electronic control device with the single power module.

[0049] Furthermore, in the present embodiment, the power modules 11a and 11b are arranged on the same plane, and the power terminals 32 of power module 11a are drawn from the longitudinal end region 311 of the main unit 31 of power module 11a, which faces the longitudinal end region 311 of the main unit 31 of power module 11b. Since the power terminals 32 of power module 11a and the power terminals 32 of power module 11b, which have opposite polarities to each other, can be arranged close together in this configuration so that they face each other, it is possible to reduce the inductance of the power circuit while avoiding an increase in the size of the electronic control device.

[0050] Furthermore, the power terminals 32 of the power modules 11a, 11b are designed such that the protruding lengths of the negative electrode-side power terminals in the lateral direction of the main unit 31 are shorter than those of the positive electrode-side power terminals. Since the protruding lengths of the positive and negative electrode-side power terminals in the lateral direction of the main unit 31, as in Fig. Since the power modules 11a and 11b are different as shown in Figure 3, they can be arranged closer together on the same plane. This makes it possible to improve the reduction in inductance of the power circuit. Furthermore, a reduction in the size of the electronic control device 9 can be achieved.

[0051] Furthermore, the power modules 11a and 11b are as described in Fig.As shown in Figure 1, the control connections 33 of the power modules 11a, 11b are arranged in the same plane at the end region of the frame end 14, and the control connections 33 of the power modules 11a, 11b are drawn from the non-facing end regions of the power modules 11a, 11b (i.e., from the end regions of the power modules 11a, 11b that each face an inner surface 242 of the housing 24 that accommodates the power modules 11a, 11b). Since the control connections 33 can be connected and attached to the control board 13 at positions close to the edges of the control board 13 by means of this arrangement, it is possible to effectively utilize a mounting surface of the control board 13.

[0052] Furthermore, like the control connections 33, the motor connections 34 of the power modules 11a, 11b are also drawn from the opposite end regions of the power modules 11a, 11b. This arrangement allows the motor connections 34 to be electrically connected to the control board 13 or the power board 12 at positions close to the edges of the control board 13 or the power board 12. This makes it possible to keep the dead space on the control board 13 or the power board 12 to a minimum. Effective use of the mounting area of ​​the control board 13 or the power board 12 is thus possible.

[0053] Although the present invention has been described based on the exemplary embodiment, the structure or configuration of the present invention is not limited to this embodiment. The present invention includes all design modifications and equivalents that fall within the technical scope of the present invention.

[0054] Although the embodiment described above illustrates the electronic control device with the dual-system power modules, the present invention can be applied to an electronic control device comprising a plurality of power modules, such as power modules with four systems or power modules with six systems. In this case, too, the same effect as that of the embodiment described above can be achieved.

[0055] Furthermore, the arrangement of the power module of the present invention is not limited to the electronic control device of the rack-and-pinion electric power steering system described above. The arrangement of the power module of the present invention can, for example, be applied to an electronic control device of a column-mounted electronic power steering system, and can also be applied to an electronic control device of a control system with an electric motor, such as a brake control device.

Claims

[1] Electronic control device (9) controlling a motor (8), comprising: a variety of power modules (11a, 11b) configured to drive the motor (8), wherein the power terminals (32) of the at least one power module (11a) from the plurality of power modules (11a, 11b) are arranged at positions that are close to each other and face the power terminals (32) of the other power module (11b), wherein the power terminals (32) of one power module (11a) and the power terminals (32) of the other power module (11b) have opposite polarity to each other, where: the multitude of power modules (11a, 11b) are arranged on the same level, and the power connections (32) of one power module (11a) are drawn from an end area (311) of a main unit (31) of one power module (11a) facing the other power module (11b); and where: the protruding lengths, in the width direction of the module main unit (31), of the positive and negative electrode side terminals of the power terminals (32) differ from each other. [2] Electronic control unit (9) according to claim 1, wherein: Control connections (33) of one power module (11a) are drawn from an end area (312) of the main unit (31) of the other power module (11a) that does not face the other power module (11b). [3] Electronic control device (9) according to claim 2, wherein: Motor connections (34) of one power module (11a) are drawn from an end area (312) of the main unit (31) of one power module (11a) that does not face the other power module (11b). [4] Electronic control device (9) according to claim 2 or 3, further comprising: a power board (12) to which the power terminals (32) of the power modules (11a, 11b) are electrically connected; a control board (13) to which the control terminals (33) of the power modules (11a, 11b) are electrically connected; and a housing (24) which accommodates the power modules (11a, 11b), the power board (12) and the control board (13), wherein the control connections (33) of the one power module (11a) are drawn from an end area (312) of the main unit (31) of the one power module (11a) facing an inner surface (242) of the housing (24). [5] Electronic control device (9) according to claim 2 or 3, further comprising: a power board (12) to which the power terminals (32) and the motor terminals (34) of the power modules (11a, 11b) are electrically connected; a control board (13) to which the control terminals (33) of the power modules (11a, 11b) are electrically connected; and a housing (24) which accommodates the power modules (11a, 11b), the power board (12) and the control board (13), wherein the control terminals (33) and the motor terminals (34) of the one power module (11a) are drawn from an end area (312) of the main unit (31) of the one power module (11a) facing an inner surface (242) of the housing (24). [6] Electronic control device (9) according to claim 2 or 3, wherein: a power board (12) to which the power terminals (32) of the power modules (11a, 11b) are electrically connected; a control board (13) to which the control terminals (33) and the motor terminals (34) of the power modules (11a, 11b) are electrically connected; and a housing (24) which accommodates the power modules (11a, 11b), the power board (12) and the control board (13), wherein the control terminals (33) and the motor terminals (34) of the one power module (11a) are drawn from an end area (312) of the main unit (31) of the one power module (11a) facing an inner surface (242) of the housing (24). [7] Electric power steering device comprising: a variety of power modules (11a, 11b) configured to drive a motor (8), wherein the power terminals (32) of at least one power module (11a) from the plurality of power modules (11a, 11b) are arranged at positions that are close to each other and face the power terminals (32) of the other power module (11b), wherein the power terminals (32) of one power module (11a) and the power terminals (32) of the other power module (11b) have opposite polarity to each other, wherein: the multitude of power modules (11a, 11b) are arranged on the same level, and the power connections (32) of one power module (11a) are drawn from an end area (311) of a main unit (31) of one power module (11a) facing the other power module (11b); and where: the protruding lengths, in the width direction of the module main unit (31), of the positive and negative electrode side terminals of the power terminals (32) differ from each other.

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