JP4045923B2 - Electric motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric motor having a power driver.
[0002]
[Prior art]
[Patent Literature]
JP-A-6-197494.
[0003]
In the electric motor shown in the above-mentioned patent document, the power switching element of the power driver is directly mounted on the side surface of the motor frame.
[0004]
[Problems to be solved by the invention]
In this conventional example, the three-phase output lead wires having different lengths are wired from the power switching element arranged outside the motor frame to the motor winding arranged inside the motor frame. Becomes longer. Further, when the motor winding collects the three-phase AC output lines of the respective stator coils within the motor, the wiring distance to the respective stator coils further varies. As a result, there is a problem that switching noise radiation becomes large, and torque fluctuation occurs due to an imbalance in the current of each motor winding.
[0005]
The present invention has been made to solve the above-described problems, and an object thereof is to provide an electric motor that can achieve suppression of noise emission from a power supply line and an AC output line for supplying electric power and suppression of torque fluctuation of a motor. Yes.
[0006]
[Means for Solving the Problems]
According to the present invention, an annular rotor, a stator that is disposed in a hollow portion of the rotor, a plurality of stator cores are formed in a convex shape, and a stator coil is wound around the stator core, and inside the stator An electric motor comprising: a power driver arranged to drive the stator coil; and an annular bus bar arranged in a hollow portion inside the stator to supply power to the power driver, wherein the number of the power drivers is The number of stator cores is the same as the number of stator cores, the power drivers are arranged close to the stator cores, and the stator coils wound around the stator cores are electrically connected to the power drivers other than the power drivers closest to the stator coils. It is configured as follows.
[0007]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the noise radiation from the power supply line which supplies electric power to a power driver can be suppressed, the noise radiation from the alternating current output line of a power driver can be suppressed, and the torque fluctuation of an electric motor can also be suppressed. Furthermore, by electrically connecting the stator coil and a power driver other than the most recent power driver, the timing at which the stator coil and the most recent power driver generate heat can be shifted. There is an effect that driving ability can be generated.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, components having the same function are denoted by the same reference numerals, and repeated description thereof is omitted.
[0009]
FIG. 1 is a view showing a first embodiment of the present invention, FIG. 1 (a) is a sectional view of an electric motor, FIG. 1 (b) is an internal side schematic view showing the internal configuration of the electric motor in an easy-to-understand manner, FIG.1 (c) is an external side view of an electric motor.
[0010]
In FIG. 1, an annular rotor 101 is installed at the outermost part, and a magnet 102 is built in the rotor 101. A stator 109 is disposed in the inner hollow portion of the rotor 101. A stator core 104 is formed in a convex shape on the stator 109, and a stator coil 103 is wound around the stator core 104. Inside the stator 109, a power driver 105 that drives the stator coil 103 is disposed close to the stator core 104. As apparent from FIG. 1 (a), the stator core 104, the stator coil 103, and the power driver 105 are formed at positions other than the numbered positions. However, for convenience of explanation, the stator core 104, the stator coil are respectively described. 103, only the power driver 105 is numbered. Here, six power drivers 105 and six stator cores 104 around which the stator coil 103 is wound are shown in the figure, and two pieces facing each other in a point symmetry form U phase, V phase, and W phase of the three-phase AC motor. It corresponds. The stator 109 is hollow inside, and an annular bus bar 106 is disposed in the hollow portion of the stator 109. The annular bus bar 106 is for supplying DC power to supply power to the power driver 105. As shown in FIG. 1A, the low voltage side bus bar 106a is arranged on the outer side in the outer circumferential direction from the high voltage side bus bar 106b. It has a double structure that is insulated and laminated. The power driver 105 and the annular bus bar 106 are electrically connected to each other by the high voltage side bus bar 106b and the low voltage side bus bar 106a inside the stator 109. Further, each power driver 105 and the nearest stator coil 103 are electrically connected by a three-phase AC output connection line 113 inside the stator 109.
[0011]
The rotor 101 and the motor shaft 108 are mechanically connected, and the annular bus bar 106 and the power terminal 107 are electrically connected.
[0012]
According to the first embodiment, since the power driver 105 is arranged close to the stator core 104 inside the stator 109, the stator coil 103 of each phase of the three-phase AC output and the power driver 105 are wired with the shortest distance. Is possible. As a result, noise generation from the three-phase AC output connection line 113 can be suppressed.
[0013]
Furthermore, since the wiring distance for each phase of the three-phase AC output can be made substantially the same distance, the phase shift of the current of the stator coil 103 for each phase of the three-phase AC output can be almost eliminated. The motor torque fluctuation due to the current phase shift of 103 can be eliminated.
[0014]
In addition, an annular bus bar 106 is formed in a hollow portion inside the stator 109, and the annular bus bar 106 and the power driver 105 are connected at the shortest distance. In general, it is well known that the parasitic inductance of the stacked bus bars is small, the total parasitic inductance of the power supply line from the power supply terminal 107 to the power driver 105 can be reduced, the surge voltage is reduced, and the noise radiation from the power supply line is reduced. There is also an effect that can be suppressed. By reducing the surge voltage, there is an economic and size effect that the cost can be reduced by downsizing or abolishing the snubber circuit. Further, since noise emission can be suppressed, it is not necessary to take measures against noise emission in this apparatus. Alternatively, there is an economic and size effect that a noise tolerance improvement measure for a device that malfunctions upon receiving noise radiation is not necessary.
[0015]
FIG. 2 is a cross-sectional view of an electric motor showing a second embodiment of the present invention.
[0016]
In the second embodiment shown in FIG. 2, the stator coil 103 is electrically connected not by the nearest power driver 105 but by the adjacent power driver 105 and the three-phase AC output connection line 113. A power supply capacitor 301 is installed inside the annular bus bar 106 as a capacitor.
[0017]
As shown in FIG. 2, the power supply capacitor 301 for direct current power supply that supplies power to the power driver 105 is installed in the hollow portion at the center of the stator 109, so that the distance between the annular bus bar 106 and the power supply capacitor 301 is minimized. Therefore, noise and surge voltage radiated from the power supply line can be suppressed, and the power supply capacitor 301 can be arranged efficiently, so that there is an economic and size effect.
[0018]
In addition, since the power driver 105 that is closest to the stator coil 103 is not electrically connected, the stator coil 103 and the power driver 105 that are adjacent to each other are electrically connected. The timing at which the power driver 105 generates heat and the timing at which the stator coil 103 generates heat can be shifted. Specifically, since the V-phase stator coil is disposed in the immediate vicinity of the U-phase power driver 105, the U-phase and the V-phase do not become the maximum load at the normal time. For this reason, if the cooling capacity is the same, a higher driving capacity can be generated.
[0019]
In the second embodiment, the adjacent stator coil 103 and the power driver 105 are connected. However, if the stator coil 103 and the power driver 105 other than the three-phase AC output in-phase drive are connected, The same effect as above can be obtained. Furthermore, by not limiting to adjacent ones, the degree of freedom in layout is increased, and further, the manufacturing cost can be reduced.
[0020]
FIG. 3 is a diagram of an electric motor showing a third embodiment of the present invention.
[0021]
In FIG. 3, the power driver 105 and the stator coil 103 to which the three-phase AC output of the power driver 105 is connected are arranged in close proximity, and a cooling structure is provided in an area between the power driver 105 and the stator coil 103. A cooling fluid passage (cooling water passage) 401 is disposed. The shape of the coolant passage 401 is substantially T-shaped in a direction from the center of the stator core 104 toward the power driver 105 in a cross-sectional shape orthogonal to the motor shaft 108. That is, a portion corresponding to the T-shaped horizontal bar of the coolant passage 401 is located in the vicinity of the power driver 105, and a portion corresponding to the T-shaped vertical bar of the coolant passage 401 is located in the stator core 104 portion.
[0022]
According to the third embodiment, the same number of the power drivers 105 and the stator coils 103 are arranged and brought close to each other, so that the power driver 105 and the stator coils 103 can be simultaneously provided in one coolant passage 401. And it can cool with the same efficiency for every three-phase alternating current output each phase. As a result, since there is no bias in heat generation, there is no need for an extra cooling capacity margin that allows for variations in heat generation, and the cooling cost can be reduced.
[0023]
In the third embodiment, the shape of the coolant passage 401 is a T-shape. However, the same effect can be obtained by using a single-shape formed in parallel with the power driver 105 between the power driver 105 and the stator core. Is obtained. Although the degree of the cooling effect is inferior to that of the T-shape, there is an effect that the processing cost of the stator 109 is low because the shape of the coolant passage 401 is simple.
[0024]
FIG. 4 is a cross-sectional view of an electric motor showing a fourth embodiment.
[0025]
In the fourth embodiment, a dielectric material having a relative dielectric constant greater than 1, that is, a high dielectric constant material 501 is disposed between the high voltage side bus bar 106b and the low voltage side bus bar 106a.
[0026]
According to the fourth embodiment, the high-voltage side bus bar 106b and the low-voltage side bus bar 106a are insulated and laminated, and a high dielectric constant material is interposed in the gap between the laminated high-voltage side bus bar 106b and low-voltage side bus bar 106a. Since 501 is sandwiched, it is equivalent to installing a large-capacity capacitor between the high-voltage side bus bar 106b and the low-voltage side bus bar 106a, and the power supply capacitor 301 shown in the second embodiment. In some cases, the power supply capacitor 301 itself can be abolished.
[0027]
Further, by arranging the low voltage side bus bar 106a on the outer periphery side of the high voltage side bus bar 106b, the surface area of the low voltage side bus bar 106a becomes larger than the surface area of the high voltage side bus bar 106b, and the impedance of the low voltage side bus bar 106a is reduced. In addition to lowering the noise, noise generated on the high voltage side bus bar 106b is not leaked to the outside, so that the effect of noise reduction is further increased.
[Brief description of the drawings]
FIG. 1 is a structural diagram of an electric motor according to a first embodiment of the present invention.
FIG. 2 is a sectional view of an electric motor according to a second embodiment of the present invention.
FIG. 3 is a sectional view of an electric motor according to a third embodiment of the present invention.
FIG. 4 is a sectional view of an electric motor according to a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 Rotor 103 Stator coil 104 Stator core 105 Power driver 106 Annular bus bar, 106a Low voltage side bus bar, 106b High voltage side bus bar 108 Motor shaft 109 Stator 113 Three-phase alternating current output connection line 301 Power supply capacitor 401 Coolant passage 501 High dielectric constant material

Claims (8)

An annular rotor,
A stator that is disposed in a hollow portion of the rotor , a plurality of stator cores are formed in a convex shape, and a stator coil is wound around the stator core ;
Is disposed inside the stator, and a power driver for driving the stator coil,
An annular bus bar that is arranged in a hollow portion inside the stator and supplies power to the power driver;
An electric motor comprising :
The number of the power drivers is the same as the number of the stator cores, the power drivers are arranged close to the stator cores, the stator coils wound around the stator cores, and the power drivers other than the power drivers in the immediate vicinity of the stator coils And an electric motor characterized by electrical connection . The electric motor according to claim 1 , wherein the stator coil and the power driver adjacent to the power driver closest to the stator coil are electrically connected . Claim 1 or claim 2 electric motor, wherein the having the annular bus bar capacitors disposed inside the internal said stator. The electric motor according to any one of claims 1 to 3, further comprising a cooling structure disposed in the stator and in a region sandwiched between both the stator coil and the power driver. The cooling structure is a coolant passage, and the shape of the coolant passage in the previous period is substantially T-shaped in the direction from the center of the stator core toward the power driver in a cross-sectional shape orthogonal to the motor shaft. The electric motor according to claim 4, wherein The electric motor according to any one of claims 1 to 5, characterized in that the high-voltage bus bar and the low-voltage side bus bar as the annular bus bar is used as being laminated insulated. The electric motor according to claim 6, wherein the low voltage side bus bar is disposed on the outer side in the outer circumferential direction from the high voltage side bus bar. The high voltage side bus bar and the low-voltage bus bar gap relative permittivity of claim 6 or claim 7 electric motor, wherein sandwiching the large dielectric material than 1.

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