JP2009291040A - Synchronous motor drive system - Google Patents

Abstract

The length of a power line connecting an inverter and each winding of a synchronous motor can be shortened as much as possible, and length unevenness between the power lines can be suppressed.
A plurality of upper and lower arms 14a,..., 30c are connected in parallel to a DC power source, an inverter that outputs AC power from each upper and lower arms 14a,..., 30c, and a rotation axis AX of a rotor 72. The synchronous motor drive system 2 includes a synchronous motor having a stator in which a plurality of windings 44a,..., 60c are arranged at intervals in the circumferential direction of the upper and lower arms 14a,. Corresponds to the windings 44a,..., 60c on a one-to-one basis, and each upper and lower arm and each winding in a corresponding relationship are connected to each other by power lines 102a,. Each was brought closer to the corresponding winding than any winding other than the corresponding winding.
[Selection] Figure 3

Description

  The present invention relates to a synchronous motor drive system, and more particularly to a synchronous motor drive system having a synchronous motor and an inverter for driving the synchronous motor.

  For example, in order to drive a synchronous motor used as a power source for an electric vehicle, it is necessary to convert DC power from a battery mounted on the electric vehicle into AC power using an inverter. An inverter usually has a number of upper and lower arms having a configuration in which switching elements are connected in series, corresponding to the number of phases of the synchronous motor, and DC / AC conversion is performed by turning on / off the switching elements.

In this case, since on / off switching (switching) by the switching element is performed at a relatively high speed, if a power line that supplies high-frequency power generated thereby to the synchronous motor is long, a problem that a lot of electromagnetic noise is generated occurs. .
In order to cope with this problem, Patent Document 1 discloses a controller in which an inverter and a control unit for controlling the inverter are housed in a case and integrated with an electric motor body with a heat sink interposed therebetween. ing.

According to this, since the power line can be shortened as a whole as compared with the case where the controller (inverter) and the electric motor main body are arranged apart from each other and both are connected by the power line, electromagnetic wave noise can be reduced.
JP-A-5-292703

However, even if it is a case where it is the case where it is a structure where a controller is brought close to an electric motor main body like patent document 1, length nonuniformity will arise in each electric power line which connects each winding of an inverter and a synchronous motor. This tendency becomes prominent when one phase is composed of a plurality of windings and these windings are connected in parallel.
In general, as the number of windings increases, the number of magnetic poles of the rotor also increases. As the number of magnetic poles increases, the frequency of the current flowing through the winding increases. When the current frequency is increased, the ON / OFF switching cycle of the switching element of the inverter is shortened (that is, the switching frequency is increased). When the switching frequency is increased, it is necessary to make the switching operation (switching operation) of the switching element faster and reduce the loss in the switching element.

  When the switching operation is performed at a high speed, the time change rate (di / dt) of the current flowing through the power line increases. Therefore, due to the influence of the inductance of the power line, an excessive surge voltage (L × (di / dt)) occurs. The surge voltage may cause the switching element to be destroyed. On the other hand, if an attempt is made to suppress the surge voltage, the switching operation cannot be performed at high speed, and the loss in the switching element cannot be reduced.

  The surge voltage increases as the inductance of the power line increases, in other words, as the power line becomes longer. For this reason, if there is non-uniform length between the power lines connecting the inverter and each winding of the synchronous motor, excessive switching such as selecting a switching element with excellent withstand voltage characteristics according to the longest power line. The design must have a sufficient margin.

  The present invention has been made in view of the above-described problems. The length of the power line connecting the inverter and each winding of the synchronous motor can be shortened as much as possible, and the length between the power lines can be reduced. An object of the present invention is to provide a synchronous motor drive system capable of suppressing uniformity.

  In order to achieve the above object, a synchronous motor drive system according to the present invention includes a plurality of upper and lower arms having a configuration in which switching elements are connected in series, connected in parallel to a DC power source, and the switching elements are connected in series. A synchronous motor drive system comprising: an inverter that outputs AC power from a point; and a synchronous motor having a stator in which a plurality of windings are arranged at intervals in a circumferential direction centered on a rotating shaft of the rotor The upper and lower arms have a one-to-one correspondence with the windings, and each upper and lower arm and each winding in a corresponding relationship are connected by a power line for supplying AC power, and each of the upper and lower arms is connected to each other. The windings are arranged closer to the corresponding windings than any windings other than the corresponding windings.

  According to the synchronous motor drive system having the above-described configuration, the upper and lower arms that output AC power are provided in one-to-one correspondence with the windings, and any of the windings other than the windings in which the upper and lower arms are in a corresponding relationship. In order to supply alternating current power to the winding, the length of the power line connecting each corresponding upper and lower arm and each winding should be reduced as much as possible. Can do. Moreover, since it becomes possible to arrange the length between each power line by the shortened length, the nonuniformity of the length between each power line can be suppressed.

Hereinafter, embodiments of a synchronous motor drive system according to the present invention will be described with reference to the drawings.
<Embodiment 1>
FIG. 1 is a circuit configuration diagram of a synchronous motor drive system 2 according to the first embodiment.
As shown in FIG. 1, the synchronous motor drive system 2 includes an inverter group 4 including a plurality of inverters that convert DC power from a DC power source BA such as a storage battery into three-phase AC power, and an AC output from the inverter group 4. And a synchronous motor 6 driven by electric power.

The inverter group 4 includes three inverters 8, 10, and 12 in this example.
Since each of the inverters 8, 10, and 12 has the same configuration, the inverter 8 will be described as a representative.
The inverter 8 has three upper and lower arms 14a, 16b, 18c connected in parallel to the DC power supply BA. Each of the upper and lower arms 14a, 16b, 18c is formed by connecting a switching element 32 and a switching element 34 in series. That is, the source terminal of the switching element 32 and the drain terminal of the switching element 34 are electrically connected. Since the switching elements constituting the upper and lower arms 14a, 16b, and 18c are the same, the switching elements constituting the upper and lower arms are denoted by the same reference numerals in order to avoid complexity. MOSFETs are used for the switching elements 32 and 34. In addition, not only MOSFET but what can perform other high frequency switching operation, for example, a bipolar transistor and IGBT, may be used. In this case, the switching elements 32 and 34 may be SiC (silicon carbide) -based or GaN (gallium nitride) -based wide band gap semiconductor elements.

The switching elements 32 and 34 in each of the upper and lower arms 14a, 16b and 18c are on / off controlled at a predetermined timing by a gate control signal from a control unit (not shown), whereby AC power is transmitted between the switching elements 32 and 34. Are output from the series connection points 8a, 8b and 8c.
Each of the inverters 10 and 12 has upper and lower arms 20a, 22b, and 24c composed of switching elements 32 and 34 and upper and lower arms 26a, 28b, and 30c, respectively. AC power is output from the series connection points 10a, 10b, 10c, 12a, 12b, and 12c.

Synchronous motor 6 has winding groups 38, 40, and 42 corresponding to inverters 8, 10, and 12, respectively.
The winding group 38 includes three windings 44a, 46b, and 48c. One ends of the windings 44a, 46b, and 48c are connected to each other and Y-connected. The other ends of the windings 44a, 46b, and 48c are electrically connected to the series connection points 8a, 8b, and 8c in the upper and lower arms 14a, 16b, and 18c, respectively.

  Similarly, the winding groups 40 and 42 include windings 50a, 52b, and 54c and windings 56a, 58b, and 60c, respectively. One end portions of the windings 50a, 52b, and 54c are connected to each other, and one end portions of the windings 56a, 58b, and 60c are also connected to each other. The other ends of the windings 50a, 52b, 54c are electrically connected to the series connection points 10a, 10b, 10c in the upper and lower arms 20a, 22b, 24c, respectively, and the windings 56a, 58b, 60c The other end portions are electrically connected to the series connection points 12a, 12b, 12c in the upper and lower arms 26a, 28b, 30c, respectively.

As described above, in the synchronous motor drive system 2, the upper and lower arms are provided for each winding. Note that the switching elements 32 and 34 constituting one upper and lower arm are housed in one module as will be described later, and the upper and lower arms and the windings supply DC power output from the upper and lower arms. Are connected by power lines.
Next, the structure of the synchronous motor drive system 2 will be described with reference to FIGS.

2 is a perspective view showing the external appearance of the synchronous motor drive system 2. FIG. 3 shows the interior of the synchronous motor 6 from the direction of the rotation axis AX of the rotor 72 (shaft 70) to be described later with the side plate 66 to be described later being removed. It is the schematic block diagram seen.
As shown in FIG. 2, the synchronous motor 6 includes a casing 68 including a cylindrical frame 62 centering on the rotation axis AX and side plates 64 and 66 that are plate-like members provided at both ends of the frame 62. And a later-described rotor 72 and stator 74 are housed in a casing 68.

The side plate 62 has a hollow disc shape, and the shaft 70 extends from the hollow portion (not shown in FIG. 2).
As shown in FIGS. 2 and 3, the upper and lower arms 14a, 16b, 18c, 20a, 22b, 24c, 26a, 28b, and 30c are formed on the outer peripheral surface of the frame 62 at substantially equal intervals in the circumferential direction. Is provided.

As shown in FIG. 3, a rotor 72 and a stator 74 are accommodated in the frame 62.
The rotor 72 includes a cylindrical member 76 and a cylindrical magnet 78 that is externally fixed to the cylindrical member 76. The cylindrical magnet 78 is a 10-pole magnet magnetized in the circumferential direction. A shaft 70 is inserted and fixed to the cylindrical member 76.

  The stator 74 is a plurality of (9 in this example) teeth 80a, 82a, 86a, 88b that are arranged radially at the rotation axis AX and concentrically with the rotation axis AX in the circumferential direction. , 90b, 92c, 94c, 96c, and the above-described windings 44a, 50a, 56a, 46b, 52b, 58b, 48c, 54c, 60c wound around each of these teeth by concentrated winding. Become. As is apparent from the winding mode, the central axes of the windings 44a, 50a, 56a, 46b, 52b, 58b, 48c, 54c, and 60c are oriented in the radial direction of the shaft 70.

  Among these windings 44a, 50a,..., 54c, 60c arranged in the circumferential direction around the rotation axis AX, three windings adjacent to each other in the circumferential direction (windings 44a, 50a, 56a, windings) 46b, 52b, 58b and windings 48c, 54c, 60c) are windings corresponding to the a-phase, b-phase, and c-phase in the three-phase synchronous motor 6, respectively. Of the three windings constituting each phase, the windings 50a, 52b, 54c in the middle in the circumferential direction are opposite to the windings located on both sides thereof.

The upper and lower arms 14a, 20a,..., 24c, 30c for supplying AC power to the windings 44a, 50a,..., 54c, 60c are arranged in the immediate vicinity of the corresponding windings. Here, “closest to the corresponding winding” means “is closer to the corresponding winding than any winding other than the corresponding winding”.
For example, in the case of the upper and lower arms 14a, the upper and lower arms are positioned closer to the corresponding winding 44a than any of the windings 50a, 56a, 46b, 52b, 58b, 48c, 54c, and 60c other than the corresponding winding 44a. 14a is arranged.

  In the first embodiment, the upper and lower arms 14 a, 20 a,..., 24 c, 30 c are arranged on the outer peripheral surface of the frame 62 and orthogonal to the rotation axis AX in order to realize the “closest corresponding winding” state. The windings 44a, 50a,..., 54c, 60c are arranged at positions including virtual straight lines (the central axis) passing through the corresponding windings 44a, 50a,. In other words, each of the upper and lower arms 14a, 20a,..., 24c, 30c is on the outer peripheral surface of the frame 62, and when viewed from the radial direction of the shaft 70, the corresponding windings 44a, 50a,. They are supposed to be placed in overlapping positions.

  Each of the upper and lower arms 14a, 20a, ..., 24c, 30c and the corresponding windings 44a, 50a, ..., 54c, 60c are respectively connected to the power lines 102a, 104a, 106a, 108b, 110b, 112b, 114c, 116c. , 118c. Each of the upper and lower arms 14a, 20a,..., 24c, 30c includes a power supply line to which DC power from a DC power supply BA is supplied, in addition to the power lines 102a, 104a,. However, in the structural diagram including FIG. 2, illustration of the power supply line and the signal line is omitted.

  The power lines 102a, 104a, ..., 116c, 118c are not provided separately from the windings 44a, 50a, ..., 54c, 60c, but correspond to one ends of the windings 44a, 50a, ..., 54c, 60c. The upper and lower arms 14a, 20a,..., 24c, 30c may be extended, and the extended portions may be used as the power lines 102a, 104a,. In this case, the winding (power line) preferably has a flat square shape (flat wire) rather than a circular shape (round wire). By doing so, the wiring of the power line can be facilitated, so that the productivity is improved and the connection can be made firmly, so that the reliability of the synchronous motor drive system is improved.

  As described above, the upper and lower arms 14a, 20a,..., 24c, 30c that supply AC power to the respective windings 44a, 50a,..., 54c, 60c are disposed in close proximity to the corresponding windings, respectively. The power line connecting the winding and the corresponding upper and lower arms can be made as short as possible. Thereby, the electromagnetic wave noise which generate | occur | produces with the said electric power line during the drive of the synchronous motor 6 can be reduced as much as possible.

In addition, since the lengths between the power lines can be made uniform (because nonuniform lengths between the power lines can be suppressed), a design with an excessive margin is forced when selecting a switching element. Can be avoided.
Next, the cooling means for the winding and the upper and lower arms will be described.
As shown in FIG. 3, on the outer peripheral surface of the core 100, there is a rotation axis AX between the upper and lower arms 14a, 20a,..., 24c, 30c and the corresponding windings 44a, 50a,. A groove is formed in parallel (that is, in a direction perpendicular to the paper surface), and the groove is a cooling medium flow path (hereinafter referred to as a “cooling path”) 120a, 122a, 124a, 126b, 128b, 130b, 132c, 134c, and 136c are configured. The outer periphery of the core 100 other than the cooling passages 120a, 122a,..., 134c, 136c and the inner periphery of the frame 62 are in close contact with each other, and airtightness and watertightness are ensured. As the cooling medium, for example, water (cooling water) can be used.

The cooling water flowing in from the water intake port 138 shown in FIG. 2 sequentially flows into the cooling passages 120a, 122a,..., 134c, 136c through the flow path described later, and finally flows out from the drain port 140. Will be.
In FIG. 3, the cooling water flows through the cooling paths 136a, 134c,..., 124a, 122a in the counterclockwise order first in the cooling path 120a. In addition, in FIG. 2, the flow path of the cooling water including the cooling paths 120a to 122a is indicated by a broken line.

Flow paths (hereinafter referred to as “communication paths”) 64F and 66F communicating between cooling paths adjacent in the circumferential direction are formed by a frame 62 and side plates 64 and 66, respectively.
The communication paths 64F and 66F will be described with reference to FIGS.
FIG. 4 is a view showing the side plate 64 and the side plate 66 facing surfaces arranged to face each other via the frame 62 (FIG. 2). FIG. 4A shows the side plate 64 and FIG. 4B shows the side plate 66.

4B, the side plate 66 has ribs 66R formed along the outer periphery at the end portions in the radial direction, and one side of the inner periphery of the rib 66R and the frame 62 is provided. The communication path 66F is formed by the portion. The side plate 64 shown in FIG. 4A also has a similar rib 64R, and the communication path 64F is formed by the rib 64R and a part of the inner periphery of the frame 62.
For example, FIG. 5A shows a cross-sectional view of the synchronous motor 6 (FIG. 2) cut at a position corresponding to the line E · E in FIG. 4B.

  As shown in FIG. 5A, a space surrounded by the rib 66R, a part of the frame 62, and a part of the core 100 is a communication path 66F on the side plate 66 side. As shown in FIG. 5A, at this position, the rib 64R of the side plate 64 and the inner peripheral surface of the frame 62 are in close contact with each other, and no communication path is formed. That is, when the rib is thinned and a gap (space) is provided between the rib and the inner peripheral surface of the frame 62, it becomes a communication path 66F, and the rib is thickened to increase the thickness of the rib and the frame 62. When the inner peripheral surface is brought into close contact with each other, no communication path is formed at that portion.

5 (b), FIG. 5 (c), and FIG. 5 (d) show the synchronous motor 6 (FIG. 2) in the D / D line, F / F line, and G in FIG. 4 (b), respectively. -It is sectional drawing cut | disconnected in the position corresponded to G line.
As shown in FIG. 5B, cooling water (not shown) taken from the water intake 138 flows into the communication path 66F on the side plate 66 side. The cooling water travels through the communication path 66F (FIG. 5A) and reaches the first cooling path 120a (FIGS. 5C and 3). And it passes through the cooling path 120a and reaches the communication path 64F on the side plate 64 side. Heat exchange between the heat generated in the windings and the upper and lower arms and the cooling water is mainly performed while the cooling water flows through the cooling passage 120a.

Next, the cooling water that has traveled through the communication path 64F reaches the cooling path 136c (FIG. 3). Then, it travels through the cooling path 136 and returns to the communication path (not shown) on the side plate 66 side.
As described above, the cooling water circulates in the zigzag in this order through the cooling paths 120a, 136c, 134c,..., 124a, 122a as shown by broken lines in FIG. It is discharged from the drain port 140 shown in FIG.

The present invention has been described above by taking the first embodiment as an example. However, the present invention is not limited to the above example, and may be as follows, for example.
(1) The cooling medium is not limited to water but may be other liquids such as oil, and is not limited to liquids, and may be gas such as air.
(2) In the above example, the cooling path is configured by providing a groove on the outer periphery of the core. However, the present invention is not limited to this, and a member other than the core, for example, a cooling pipe between the winding and the corresponding upper and lower arms The cooling path may be configured by meandering so as to pass through the pipe.
(3) The above example is a synchronous motor (SPMSM) having a surface magnet structure in which a permanent magnet is attached to the rotor surface. However, the present invention is not limited to this, and an embedded magnet having a permanent magnet embedded in the rotor. It can also be applied to a synchronous motor (IPMSM) with a structure. Or it is applicable also to the reluctance torque application electric motor made into the rotor comprised only with the electromagnetic steel plate, without using a permanent magnet.
(4) In the above example, the winding is wound around the tooth, but it may be an air-core winding without a tooth (that is, without a core).
<Embodiment 2>
In the first embodiment, each of the upper and lower arms is arranged on the outer periphery of the frame 62, that is, on the cylindrical surface. However, in the synchronous motor drive system 150 of the second embodiment, the upper and lower arms are arranged on a plane orthogonal to the rotation axis AX. did.

Specifically, as shown in FIG. 6, the substrate 152 is attached to the side plate 66, and the upper and lower arms 14 a, 20 a,..., 24 c, 30 c are arranged on the main surface of the substrate 152.
The synchronous motor drive system 150 of the second embodiment is different from the synchronous motor drive system 2 of the first embodiment except that the arrangement positions of the upper and lower arms 14a, 20a,..., 24c, 30c are different (FIG. 1). Is basically the same.

Therefore, in the synchronous motor drive system 150, the same code | symbol is attached | subjected about the structure similar to the synchronous motor drive system 2 of Embodiment 1, and the detailed description is abbreviate | omitted.
As described above, as shown in FIG. 6, the substrate 152, which is a disk-shaped member that is stacked on the side plate 66, is attached, and the upper and lower arms 14 a, 20 a,. It was decided to distribute. Since some types of electric motors have the frame 62 as described above, the upper and lower arms can be integrally attached to the synchronous motor by providing the substrate in this manner.

In FIG. 7, the side view seen from the rotating shaft AX direction is shown. The components present inside the synchronous motor 6 are drawn with broken lines.
Also in the second embodiment, as in the first embodiment, the upper and lower arms 14a, 20a,..., 24c, 30c that supply AC power to the windings 44a, 50a,. Arranged most recently. That is, for example, in the case of the upper and lower arms 14a, any winding 50a, 56a, 46b, 52b, 58b, 48c, 54c, 60c other than the corresponding winding 44a is closer to the corresponding winding 44a and The upper and lower arms 14a are arranged.

Specifically, in order to realize the “closest to the corresponding winding” state, in the second embodiment, the upper and lower arms 14a, 20a,..., 24c, 30c are arranged on the main surface of the substrate 152, As shown in FIG. 7, when the synchronous motor 6 is viewed from the direction of the rotation axis AX, the corresponding windings 44a, 50a,.
Each of the upper and lower arms 14a, 20a, ..., 24c, 30c and the corresponding windings 44a, 50a, ..., 54c, 60c are inserted through holes (not shown) provided in the substrate 152 and the side plate 66. The power lines 102a, 104a, 106a, 108b, 110b, 112b, 114c, 116c, and 118c are connected to each other (FIG. 6).
<Embodiment 3>
FIG. 8 shows a circuit configuration diagram of a synchronous motor drive system 150 according to the third embodiment.

The synchronous motor drive system 150 includes an inverter group 180 including three inverters 182, 184, 186, similar to the synchronous motor drive system 2 (FIG. 1) of the first embodiment, and each of the inverters 182, 184, 186 is provided. And upper and lower arms 14a, 16b, 18c, upper and lower arms 20a, 22b, 24c, and upper and lower arms 26a, 28b, 30c.
Synchronous motor drive system 150 corresponds to synchronous motor drive system 2 of the first embodiment (FIG. 1).
The difference is that the capacitors 162a, 164b, 166c, 168a, 170b, 172c, 174a, 176b, 178c are connected in parallel to the upper and lower arms 14a, 16b, 18c, 20a, 22b, 24c, 26a, 28b, 30c, respectively. It is in the point. Except for the difference, the synchronous motor drive system 150 is basically similar in configuration to the synchronous motor drive system 2 of the first embodiment, and therefore, common portions are denoted by the same reference numerals and description thereof is omitted. The description will focus on the different parts.

  As described above, by providing the capacitors 162a, 164b, ..., 176b, 178c, it is possible to suppress the generation of surge voltage due to the switching operation of the upper and lower arms 14a, 16b, ..., 28b, 30c. As the capacitor, a ceramic capacitor having excellent temperature characteristics, a film capacitor having excellent frequency characteristics, and an electrolytic capacitor advantageous for downsizing can be used.

The arrangement positions of the capacitors 162a, 164b, ..., 176b, 178c and the upper and lower arms 14a, 16b, ..., 28b, 30c will be described with reference to FIG.
FIG. 9 is a perspective view showing the external appearance of the synchronous motor drive system 160, which is drawn in the same manner as FIG.
The synchronous motor drive system 160 is provided with a substrate 188 which is a plate-like member for integrally attaching the capacitors 162a, 164b,..., 176b, 178c to the casing 68, and the capacitors 162a, 164b,. Except for being mounted on 178c, it is basically the same as the synchronous motor drive system 2 (FIG. 2) of the first embodiment, including the arrangement positions of the upper and lower arms 14a, 16b,..., 28b, 30c. Note that the substrate 188 can be the same as the substrate 152 in Embodiment 2.

  As shown in FIG. 9, each of capacitors 162a, 164b,..., 176b, 178c is arranged on the main surface of substrate 188 and in the vicinity of the corresponding upper and lower arms 14a, 16b,. Yes. Here, “in the vicinity of the corresponding vertical arm” means “is closer to the corresponding vertical arm than any vertical arm other than the corresponding vertical arm”.

For example, in the case of the capacitor 162a, the upper and lower arms 16b, 18c, 20a, 22b, 24c, 26a, 28b, and 30c other than the corresponding upper and lower arms 14a are closer to the corresponding upper and lower arms 14a and the capacitor 162a is moved closer to the upper and lower arms 14a. It is arranged.
In the present embodiment, in order to realize the “near the corresponding upper and lower arms” state, each of the capacitors 162a, 164b,..., 176b, 178c is arranged on the main surface of the substrate 188 with a circumference around the rotation axis AX. On the top, it was arranged in the same angular position as the corresponding upper and lower arms in the circumferential direction. As a result, as described above, the upper and lower arms 14a, 16b,..., 28b, 30c are arranged at equal intervals (equal angular intervals) on the outer peripheral surface of the frame 62, so that the capacitors 162a, 164b,. 178c is also arranged on the substrate 188 at equal intervals (equal angular intervals).

  By arranging the capacitors 162a, 164b,..., 176b, 178c in this way, the length of the wiring connected to the corresponding upper and lower arms can be shortened as much as possible. In FIG. 9, illustration of wirings connecting the capacitors 162a, 164b,..., 176b, 178c and the corresponding upper and lower arms 14a, 16b,.

In the above example, the upper and lower arms 14a, 16b, ..., 28b, 30c are provided on the outer peripheral surface of the frame 62, and the capacitors 162a, 164b, ..., 176b, 178c are provided on the main surface of the substrate 188. And the position of the capacitor may be reversed. That is, the upper and lower arms 14a, 16b,..., 28b, 30c may be provided on the main surface of the substrate 188, and the capacitors 162a, 164b,. In other words, for example, the arrangement of the upper and lower arms 14a and the corresponding capacitors 162a are interchanged.
<Embodiment 4>
Although the first to third embodiments are examples in which the present invention is applied to an inner rotor type synchronous motor, the fourth embodiment is an example in which the present invention is applied to an outer rotor type synchronous motor. The first to third embodiments are 10-pole, 9-slot synchronous motors, but the fourth embodiment is a 14-pole, 12-slot synchronous motor.

10 and 11 show a synchronous motor drive system 200 according to the fourth embodiment.
FIG. 10 is a front view in which only the outer rotor 206 is cut, and FIG. 11 is a side view as viewed from the opposite side of the shaft 208 protruding in the direction of the rotation axis AX of the outer rotor 206.
As shown in FIGS. 10 and 11, the synchronous motor drive system 200 includes a synchronous motor 202 and a plurality of (in this example, 12) upper and lower arms 238a, 240a, 242b, 244b, 246c, 248c, 250a, 252a, 254b, 256b, 258c, 256c.

The synchronous motor 202 has a cup-shaped rotor 206 provided with a cylindrical magnet 204. A shaft 208 is fixed to the rotor 206. The shaft 208 is rotatably supported in a cylindrical frame 210 that houses the stator.
In the frame 210, a plurality of (in this example, twelve) windings 210a, 212a, and 214b arranged in the circumferential direction of the inner circumferential surface thereof (that is, in the circumferential direction around the rotation axis AX). 216b, 218c, 220c, 222a, 224a, 226b, 228b, 230c, and 232c are accommodated. Of the windings, four windings with the same alphabet are in phase.

At both ends of the frame 210, a substrate 234 and a substrate 236, which are plate-like members orthogonal to the rotation axis AX, are provided.
Of the twelve upper and lower arms, the upper and lower arms 238a, 242b, 246c, 250a, 254b, and 258c are provided on the substrate 234, and the upper and lower arms 240a, 244b, 248c, 252a, 256b, and 256c are provided on the substrate 236. . In this way, the upper and lower arms are provided separately for the substrate 234 and the substrate 236. In the outer rotor type synchronous motor, the stator is located inside the rotor, so that the same size inner rotor type synchronous motor is used. In comparison, since the areas of the substrates 234 and 236 are reduced, it is often difficult to arrange all the upper and lower arms on only one substrate.

In addition, even if there is room in the space, by disposing the upper and lower arms on the substrate 234 and the substrate 236, the heat radiation emitted from the upper and lower arms is improved compared to the case where only one is provided. can do.
Even in the above configuration, the upper and lower arms 238a, 240a, 242b, 244b, 246c, and 248c that supply AC power to the windings 210a, 212a, 214b, 216b, 218c, 220c, 222a, 224a, 226b, 228b, 230c, and 232c. , 250a, 252a, 254b, 256b, 258c, and 256c are arranged in close proximity to the corresponding windings.

For example, in the case of the upper and lower arms 238a, the windings 212a, 214b, 216b, 218c, 220c, 222a, 224a, 226b, 228b, 230c, and 232c other than the corresponding winding 210a are connected to the corresponding winding 210a. The upper and lower arms 238a are arranged close to each other.
More specifically, in the fourth embodiment, the upper and lower arms 238a, 240a,... 258c, 256c are on the main surfaces of the corresponding substrates 234, 236, respectively, as shown in FIG. When the synchronous motor 202 is viewed from the side (from the direction of the rotation axis AX), the corresponding windings 210a, 212a,..., 230c, 232c are arranged at positions that at least partially overlap.

The upper and lower arms 238a, 240a, ..., 258c, 256c and the corresponding windings 210a, 212a, ..., 230c, 232c are power lines inserted through holes (not shown) provided in the substrates 234, 236. (Not shown).
In addition, the winding start ends of the windings 210a, 212a,..., 230c, 232c to the corresponding teeth and connected to the power line are aligned with the corresponding upper and lower arms. This is because each power line is shortened as much as possible and the line length of each power line is made as equal as possible.
<Embodiment 5>
The core 100 (FIG. 3) of the stator 74 of the first embodiment is an integrated core in which the teeth 80a, 82a,..., 94c, 96c are integrally connected. A divided stator core is used that is divided for each tooth.
(Embodiment 5-1)
FIG. 12A shows a split stator core 320 according to Embodiment 5-1. A winding 306 is wound around the teeth 304 of the divided stator core 320. In the embodiment 5-1, the divided stator core 320 around which the winding 306 is wound is circumferential on the circumference around the rotation axis AX, similarly to the synchronous motor 202 of the first embodiment shown in FIG. Nine of them are arranged to form a stator.

  Further, in the fifth embodiment, the upper and lower arms 310 corresponding to the winding 306 (that is, supplying AC power to the winding 306) are divided into the stator core 320 in order to further shorten the power line 308 than in the case of the first embodiment. We decided to attach directly to. The upper and lower arms 310 can be the same as the upper and lower arms of the first embodiment, and the upper and lower arms 310 are fixed to the split stator core 320 with a heat resistant adhesive or the like (not shown).

In addition, a through-hole may be opened in a direction perpendicular to the paper surface at a position indicated by a one-dot chain line of the divided stator core 320, and the cooling path 132 similar to that of the first embodiment may be used. In this case, the cooling paths 132 of the adjacent split stator cores 320 are sequentially connected by, for example, a tube or the like (not shown) adapted to the cross-sectional shape of the cooling path 132, and the tube of the first embodiment is connected by the tube. A thing corresponding to a passage can be constituted.
(Embodiment 5-2)
In the embodiment 5-2, the concave portion 322u is formed in the divided stator core 322, and the upper and lower arms 310 are embedded in the concave portion 322u.

Since the configuration is the same as that of Embodiment 5-1, except that the upper and lower arms 310 are embedded, the same components are denoted by the same reference numerals, and the description thereof is omitted.
(Embodiment 5-3)
In the embodiment 5-3, the configuration of the embodiment 5-2, that is, the divided stator core 322 in which the upper and lower arms 310 are embedded and the winding 306 is wound, the mold member 332 together with the upper and lower arms 310 and the winding 306 is used. It was decided to cover with. For the mold member 332, a material excellent in electrical insulation and heat transfer, such as silicon rubber, can be used.

  The split stator core 322 is not completely covered with the molding material 332, but the core portions 322a and 322b that are in contact with the adjacent split stator core (not shown) are exposed. Needless to say, in order to connect a power line from a DC power source, a terminal portion (not shown) provided on the upper and lower arms 310 and a signal line for transmitting a gate control signal from a control unit (not shown) are connected. A terminal portion (not shown) is also exposed from the molding material 332.

  According to the synchronous motor drive system according to the fifth embodiment, it is possible to perform a predetermined inspection for each divided stator core in which the upper and lower arms are attached and the winding is wound. For this reason, the yield as a product improves and productivity improves compared with the case where the integrated core which cannot be test | inspected if it is not the state completed as a stator is used.

  The present invention can be suitably used for a synchronous motor drive system used as a power source for an electric vehicle, a hybrid vehicle, a fuel cell vehicle, and the like that are particularly required to have low electromagnetic noise.

1 is a circuit configuration diagram of a synchronous motor drive system according to Embodiment 1. FIG. 1 is a perspective view showing an external appearance of a synchronous motor drive system according to Embodiment 1. FIG. It is the schematic block diagram which looked at the inside of the said synchronous motor from the axial direction of the shaft in the state except the side plate of the synchronous motor which comprises the synchronous motor drive system which concerns on Embodiment 1. FIG. (A), (b) is the figure which each represented the opposing surface of the two side plates arrange | positioned through the flame | frame in the said synchronous motor. (A), (b), (c), and (d) show the synchronous motor in the EE line, D / D line, F / F line, and G / G in FIG. 4 (b), respectively. It is the fragmentary sectional view cut | disconnected in the position corresponded to a line. It is a perspective view which shows the external appearance of the synchronous motor drive system which concerns on Embodiment 2. FIG. It is the side view which looked at the synchronous motor drive system which concerns on Embodiment 2 from the axial center direction of the shaft of a synchronous motor. FIG. 6 is a circuit configuration diagram of a synchronous motor drive system according to a third embodiment. FIG. 10 is a perspective view showing an external appearance of a synchronous motor drive system according to Embodiment 3. In the synchronous motor drive system which concerns on Embodiment 4, it is the front view which cut | disconnected only the outer rotor. It is the side view which looked at the synchronous motor drive system concerning Embodiment 4 from the opposite side to the shaft in the axial direction of the shaft. (A), (b), (c) are upper and lower arms on a split stator core around which windings are wound, which are constituent members of the synchronous motor of the synchronous motor drive system according to Embodiments 5-1 to 3, respectively. It is a figure which shows what was attached.

Explanation of symbols

2,150,160,200 Synchronous motor drive system 6,202 Synchronous motor 8,10,12 Inverter 14a, 16b, 18c, 20a, 22b, 24c, 26a, 28b, 30c, 238a, 240a, 242b, 244b, 246c, 248c, 250a, 252a, 254b, 256b, 258c, 256c, 310 Upper and lower arms 32, 34 Switching element 44a, 50a, 56a, 46b, 52b, 58b, 48c, 54c, 60c Winding 72, 206 Rotor 74 Stator 102a, 104a , 106a, 108b, 110b, 112b, 114c, 116c, 118c, 308 Power line

Claims (9)

An inverter that connects a plurality of upper and lower arms having a configuration in which switching elements are connected in series to a DC power supply in parallel, and outputs AC power from a series connection point of the switching elements;
A synchronous motor having a stator in which a plurality of windings are arranged at intervals in a circumferential direction around the rotation axis of the rotor;
A synchronous motor drive system comprising:
The upper and lower arms have a one-to-one correspondence with the windings, and the corresponding upper and lower arms and the windings are connected by a power line for supplying AC power, and the upper and lower arms are in a corresponding relationship. A synchronous motor drive system, characterized in that the synchronous motor drive system is arranged closer to the corresponding winding than any other winding.   2. The synchronous motor drive system according to claim 1, wherein each of the upper and lower arms is arranged at a position including a straight line that passes through a winding that is orthogonal to the rotation axis and has a corresponding relationship. The synchronous motor has a frame that houses the plurality of windings,
The synchronous motor drive system according to claim 2, wherein each of the upper and lower arms is disposed on an outer peripheral surface of the frame.   3. The stator according to claim 2, wherein the stator includes a core provided for each of the windings and having a tooth around which each winding is wound, and each of the upper and lower arms is attached to the core. Synchronous motor drive system.   2. The synchronous motor drive system according to claim 1, wherein each of the upper and lower arms is disposed at a position overlapping a winding having a corresponding relationship when viewed from the rotation axis direction. The synchronous motor has a plate-like member orthogonal to the rotation axis,
The synchronous motor drive system according to claim 5, wherein each of the upper and lower arms is disposed on a main surface of the plate-like member.   Capacitors are connected in parallel to each of the upper and lower arms, and each of the capacitors is closer to the upper and lower arms of the connection destination than any of the upper and lower arms other than the connection upper and lower arms. The synchronous motor drive system according to any one of claims 1 to 6.   The synchronous motor drive according to any one of claims 1 to 7, wherein a cooling path through which a cooling medium flows is provided between each of the corresponding upper and lower arms and each winding. system.   The synchronous motor drive system according to any one of claims 1 to 8, wherein the switching element is configured by a wide band gap semiconductor containing silicon carbide or nitrogen gallium.

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