JPH06205573A - Winding changeover type rotating electric machine - Google Patents

Abstract

PURPOSE:To provide a winding changeover rotating electric machine capable of being operated always with high efficiency or in its vicinity even if the revolution changes. CONSTITUTION:For a DC brushless motor, which has two sets of stator windings for each phase of U phase, V phase, and W phase, the S terminal and the P terminal of a PDU control unit 33 are set to 'H' level and 'L' level when the revolution is low, and composite connection transistors 322, 325, 328 are turned on, and two sets of windings of each phase are connected in series. On the other hand, when the revolution of the motor gets over a specified value, the S terminal and the P terminal of the PDU control unit 33 are set to 'L' level and 'H' level, respectively, and the composite connection transistors 321, 324, and 327, and 323, 326, and 329 are turned on, and the said two sets of windings of each phase are connected in parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winding switching type rotary electric machine such as a DC brushless motor, and more particularly to a winding switching type rotary electric machine suitable for driving a prime mover of an electric vehicle or the like.

[0002]

2. Description of the Related Art Conventionally, in a rotating electric machine such as a DC brushless motor having a plurality of phases, the number of windings of a stator winding is switched by switching the phase from three phases to one phase or from one phase to three phases. A winding switching type rotary electric machine that switches the torque of the rotary electric machine has already been proposed (for example, see JP-A-2-51349).

In the above rotary electric machine, for example, like a motor for a compressor of a refrigerator, a constant rotation speed (for example,
In the case of driving at 3000 rpm), the magnitude of torque can be switched by appropriately switching the phases, and the efficiency of the load current can be improved.

FIG. 9 is an output characteristic diagram of a DC brushless motor. FIG. 9A shows a case where the torque constant is large, that is,
The output characteristic is shown when the number of turns of the winding is large (for example, 1000 turns), and (b) shows the output characteristic when the torque constant is small, that is, when the number of turns of the winding is small (for example, 100 turns). ing. In the figure, the horizontal axis shows the rotation speed of the rotating electric machine, the vertical axis shows the output of the rotating electric machine, and the curve shown by the solid line connects the same efficiency points. Is large and the number of turns is large, the maximum efficiency region exists in a predetermined low rotation range, and when the torque constant is small and the number of turns is small, the maximum efficiency region exists in a predetermined high rotation range.

[0005]

However, in the synchronous rotary electric machine as described above, there is a proportional relationship between the stator winding and the torque constant, and the efficiency, which is the ratio of the output to the input of the rotary electric machine, is: It is known that as the torque constant increases, the maximum efficiency region moves to the low speed rotation side, and as the torque constant decreases, it moves to the high speed rotation side.

Therefore, in the above-mentioned conventional winding switching type rotating electric machine, when it is used for driving a variable speed prime mover of an electric vehicle, for example, it is difficult to always operate near the maximum efficiency in a wide rotation range. In particular, when used in a battery-equipped electric vehicle, there is a problem that the power consumption of the battery increases and the traveling distance is hindered.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a winding switching type rotary electric machine that can always be operated near the maximum efficiency even when the rotation speed changes. .

[0008]

In order to achieve the above object, the present invention provides a stator having a plurality of sets of stator windings wound on the same pole, and a rotor having a plurality of poles magnetized. Preferably, the plurality of stator windings are switchable in accordance with changes in the number of rotations of the rotor. Preferably, the stator windings are switchable in series or in parallel. It is characterized by

[0009]

The number of windings of the stator winding can be switched according to the number of rotations of the rotor.

Specifically, it is possible to switch a plurality of stator windings in series or in parallel according to the number of rotations of the rotor.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

In this embodiment, the present invention is applied to a DC brushless motor, and FIG. 1 is a vertical sectional view of a DC brushless motor as an example of a winding switching type rotary electric machine according to the present invention. 2 is a diagram showing the left half of the cross section taken along the line XX in FIG. 1. Hereinafter, description will be made with reference to FIGS. 1 and 2.

Reference numeral 1 denotes a motor housing formed in a cylindrical shape, and both ends of the motor housing 1 are screwed by a pair of left and right end plates 3a, 3b via a suitable number of bolts 2. There is.

A stator 4 is provided inside the motor housing 1 and the end plates 3a and 3b.
And a rotor 5 are provided.

The stator 4 is formed by stacking a large number of stator cores 6 made of silicon steel plates formed in a flat shape in the axial direction, and a copper wire 8 is inserted into a slot 7 of the stator core 6. Has been done.

The rotor 5 includes a pair of left and right rotating shafts 9a,
9b, a cylindrical magnetic material 10 press-fitted and sealed by the rotary shafts 9a and 9b, a magnet 11 provided around the outer periphery of the magnetic material 10, and left and right fitted to the rotary shafts 9a and 9b. It is composed of a pair of bearings 12a and 12b and a rotation sensor 14 fixed to one of the rotating shafts 9b via a fixing tool such as a key 13. Also, the rotating shafts 9a and 9b and the magnetic material 1
The rotary shaft 9a, which is surrounded by 0 and forms a hollow part 15, has a blind end 17 having a female screw part 16 formed in the axial direction and an end part of the rotary shaft 9a. A male screw portion is formed on the male screw portion, and the power output portion 19 is fixed by screwing the nut 18 onto the male screw portion.

On the other hand, the rotary shaft 9b is also provided with a hole 21 having a female threaded portion 20 so as to allow the air to escape at the time of press-fitting. The rotary shaft 9b is covered with a rotary shaft cover 22 fixed to the end plate 3b.

The rotation sensor 14 is formed in a substantially disc shape, and the outer peripheral portion is bent in an L-shaped cross section to form a bent portion 14a. A magnet is fixed to the inner surface of the bent portion 14a so that the magnet and the Hall element 23 can face each other with a certain gap.

Further, the end plate 3b has a power supply terminal cover 24.
As shown in FIG. 2, the U terminal 25 ₁ , the V terminal 25 ₂ , and the W terminal 25, which are power feeding terminals, are fixed inside the terminal.
_Three are provided. The U terminal 25 ₁ , V terminal 25 ₂ , W
_One ends of power cords 26 _{1 to} 26 ₃ are connected to the terminal 25 ₃ , respectively. The power cords 26 _{1 to} 26 ₃ are power cords for supplying a power source voltage to be applied to the U-phase, V-phase, and W-phase of the stator winding, and each power cord is centered on a conductive wire. , The reinforcing material is coated with the insulating material, and the other ends of the power cords 26 _{1 to} 26 ₃ are connected to a winding number switching circuit and a motor drive circuit described later. Furthermore, the end plate 3b also has a U phase, V
Phase and W phase common terminal covers 27 are fixed.

Further, as shown in FIG. 1, the end plate 3b includes
The cooling cover 28 is fixed. The cooling cover 28
Is a first cooling cover 28 ₁ for sucking air, a second cooling cover 28 ₂ formed to cover the power cords 26 _{1 to} 26 _3, and a cylindrical shape for cooling the motor housing 1. And a third cooling cover 28 ₃ formed on the. A gap is formed between the cooling cover 28 and the motor housing 1 and the end plate 3b,
Air flows in through the opening of the first cooling cover 28 ₁ and the motor can be cooled. In order to increase the cooling efficiency, that is, to increase the surface area, the third
The cooling cover 28 ₃ is provided with a plurality of protrusions.
In addition, in order to improve the flow of air and improve cooling efficiency,
A guide 29 is provided inside the cooling cover 28.

Next, the winding pattern of this DC brushless motor will be described.

FIG. 3 is a conceptual diagram showing a winding pattern, and shows a case of 24 slots for simplification.

In the figure, the solid lines indicate the windings, and the numbers above them indicate the slot numbers. Also, terminals U1-1, U
Reference numerals 1-2, U2-1, U2-2 denote terminals provided on the U-phase winding, and terminals V1-1, V1-2, V2-1, V
2-2 indicates a terminal provided on the V-phase winding, and a terminal W
Reference numerals 1-1, W1-2, W2-1, and W2-2 indicate terminals provided on the W-phase winding.

Windings of different phases are inserted in the slots adjacent to each other on the left and right, and the U-phase, V-phase,
The W phase is repeatedly formed. That is, for example, in the winding of the terminal U1-1, the first slot is inserted in the axial left direction and the fourth slot is inserted in the axial right direction, then the seventh slot is reached and the first slot is inserted. Similarly to the slot No. 2, the tenth slot is inserted to the left of the shaft center, and the tenth slot is inserted to the right of the shaft center to reach the terminal U1-1. Furthermore, the terminal U1
-From 2 to the 13th slot, the 13th slot is inserted in the axial center left direction, the 16th slot is inserted in the axial center right direction, reaches the 19th slot, and the 19th slot is axial center left To the right side of the shaft center through the 22nd slot to reach the 1st slot. Similarly, the winding of the terminal U2-1 is also inserted in the same slot as the winding of the terminal U1-1 in a pattern in the opposite direction.

FIG. 4 is a diagram showing the left half of the cross section taken along the line YY of FIG. 1, and FIG. 5 is a detailed view of the portion A of FIG. 4, in which this DC brushless motor has 48 units. It has a slot.

In FIG. 4, "U", "V", and "W" indicate slots in which U-phase, V-phase, and W-phase are formed, respectively. V phase and W phase are formed. Further, in FIG. 5, the four circular cross sections in each slot are copper wires (windings) 8, and the shaded windings are inserted to the left in the axial direction of FIG. Indicate that
The windings not shaded indicate that they are inserted to the right in the axial direction of FIG.

The DC brushless motor described above,
The stator windings are configured to be switchable in series or in parallel according to the change in rotation speed.

The operating principle of the DC brushless motor will be described below.

FIG. 6 is an electric circuit diagram for controlling the drive of the DC brushless motor, in which a stator 4 having two sets of stator windings wound around each of the U-phase, V-phase and W-phase. and the feeding terminal 25 _to 253 and the motor unit 31 provided with, switches the two sets of stator windings in series or in parallel winding switching circuit 32
And a PDU control unit 33 for controlling the winding switching circuit 32, and a motor drive circuit 34 for controlling the power supply voltage applied to the stator winding of each phase.

In the motor section 31, as described above, the stator winding U1 is connected between the U1-1 terminal and the U1-2 terminal, and between the V1-1 terminal and the V1-2 terminal. Is connected to the stator winding V1, and the stator winding W1 is connected between W1-1 and W1-2. Also, U2-
The stator windings U2, V2 and W2 are connected between the 1 terminal, the V2-1 terminal and the W2-1 terminal and the common terminal U2-2 terminal, the V2-2 terminal and the W2-2 terminal, respectively. There is.

The winding switching circuit 32 is a composite connection transistor 3 composed of two transistors in which the collector of one transistor is connected to the emitter of the other transistor.
And a 2 _{1-32 9.} As will be described later, a current is supplied to the stator winding from the connection point of the composite connection transistor, and hence this connection point is hereinafter referred to as an “input / output terminal”.

That is, one input / output terminal 32 ₁₁ of the composite connection transistor 32 ₁ is connected to the U terminal of the motor drive circuit 34 and the U1-1 terminal, and the other input / output terminal is 3
2 ₁₂ is connected to one input / output terminal 32 ₂₁ of the composite connection transistor 32 ₂ and the U2-1 terminal. The other input / output terminal 32 of the composite connection transistor 32 _2.
22 is the terminal U1-2 and the composite connection transistor 3
2 ₃ is connected to one input / output terminal 32 ₃₁ and the other input / output terminal 32 ₃₂ of the composite connection transistor 32 ₃ is connected to the W
It is connected to the 2-2 terminal. Further, each of the two bases of the composite connection transistors 32 ₁ and 32 ₃ has the above-mentioned P
The two bases of the composite connection transistor 32 ₂ connected to the P terminal of the DU control unit 33 are the PD
It is connected to the S terminal of the U control unit 33.

Similarly, the composite connection transistor 32 ₄
One input / output terminal 32 ₄₁ is connected to the motor drive circuit 34
, And the other input / output terminal 32 ₄₂ is connected to one input / output terminal 32 ₅₁ of the composite connection transistor 32 ₅ and the V1-2 terminal. The other input / output terminal 32 ₅₂ of the composite connection transistor 32 ₅ is connected to one input / output terminal 32 ₆₁ of the composite connection transistor 32 ₆ and the V1-2 terminal, and the other input / output terminal 32 _{62 of the} composite connection transistor 32 ₆ is connected. Is
It is connected to the W2-2 terminal. Furthermore, the two bases of each of the composite connection transistors 32 ₄ and 32 ₆ are
It is connected to the P terminal of the PDU control unit 33, and the two bases of the composite connection transistor 32 ₅ are connected to the S terminal of the PDU control unit 33.

Further, similarly, one input / output terminal 32 ₇₁ of the composite connection transistor 32 ₇ is connected to the W terminal and the W1-1 terminal of the motor drive circuit 34,
The other input / output terminal 32 ₇₂ is the composite connection transistor 32.
It is connected to one of the _eight input / output terminals 32 ₈₁ and the W1-2 terminal. The other input / output terminal 32 ₈₂ of the composite connection transistor 32 ₈ is connected to one input / output terminal 32 ₉₁ of the composite connection transistor 32 ₉ and the W1-2 terminal, and the other input / output terminal 3 of the composite connection transistor 32 ₉ is connected.
2 ₉₂ is connected to the W2-2 terminal. further,
Two bases of each of the composite connection transistors 32 ₇ and 32 ₉ are connected to the P terminal of the PDU control unit 33, and two bases of the composite connection transistor 32 ₈ are connected to the S terminal of the PDU control unit 33. Has been done.

The control operation of the winding switching type rotary electric machine of the present invention will be described below in detail.

When the motor is started, the PDU control unit 33 sets the S terminal to the "H" level and the P terminal to the "L" level to connect the windings of each phase in series. . For example, when a voltage E is applied between the U phase and the V phase and a winding current flows in the direction from the U phase to the V phase, the current flows from the U terminal through the winding U1 to the composite connection transistor 32 ₂ . as, via the windings U2 and winding V2, through the composite connection transistor 32 _5, will flow into the V terminal after being subjected to a winding V1, the two sets of windings of U-phase and V-phase is connected in series It was done.

Next, the rotation speed increases, and as described above,
When the motor reaches a predetermined speed and the efficiency begins to drop from the maximum efficiency area, the PDU control unit 33
The terminals are set to "L" level, the P terminals are set to "H" level, and the windings of each phase are connected in parallel. For example, when a voltage E is applied between the U-phase and the V-phase, as in the case of the series connection, current flows from the U terminal through the winding U1 to the composite connection transistor 32 ₃ and the composite connection transistor 32 ₅ . There is one that flows through the winding V1 to the V terminal and another that flows from the U terminal through the composite connection transistor 32 ₁ and through the windings U2 and V2 through the composite connection transistor 32 1 to the V terminal. Each of the two windings of the phase and the V phase is connected in parallel.

Next, the relationship between the winding resistance of the stator winding and the copper loss will be described.

FIGS. 7A and 7B are circuit diagrams when the two sets of stator windings are connected in series and in parallel, respectively. In the figure, the resistance values and inductances of the two sets of stator windings are r (Ω) and L, respectively.
(H), the power supply voltage E is applied between the U phase and the V phase, and the current flows in the direction from the U phase to the V phase. When the number of turns of the stator winding is n, 1 when the stator winding is connected in series (hereinafter referred to as "in series")
The number of turns Ns per phase is 2n, which is 1 when the stator windings are connected in parallel (hereinafter referred to as "in parallel").
The number of turns Ns per phase is n. Since the torque constant is proportional to the number of turns equivalent to one as described above, the torque constant Kts in series is twice the torque constant Ktp in parallel.

Further, in series and in parallel, the currents required to obtain the torque T are Is and Ip, respectively.
Then, the currents Is and Ip are obtained according to the mathematical expressions (1) and (2).

Is = T / Kts (1) Ip = T / Ktp = T / (Kts / 2) = 2Is (2) Furthermore, the winding resistance per phase in series and in parallel is respectively determined. Assuming Rs and Rp, the equations (3) and (4) are obtained.

Rs = 2r (3) Rp = r / 2 (4) Therefore, the copper loss Pcs and the copper loss Pcp in the series and in the parallel are as shown in the equations (5) and (6). .

Pcs = Is ² Rs = 2Is ² r (5) Pcp = Ip ² Rp = (2Is) ² r / 2 = 2Is ² r (6) Further, the inductances in series and in parallel are Assuming that Lp and Ls are used, the equations (7) and (8) are obtained.

Lp = 2L (7) Ls = L / 2 (8) As described above, the copper loss does not change even when the number of turns is changed, and when the current is changed in series and in parallel, Since there is no coil that does not flow, the coil can be used efficiently and effectively.

FIG. 8 is an output characteristic diagram of the DC brushless motor of this embodiment. First, the motor is operated in a state where the number of windings of the stator winding is large (characteristic of FIG. 9A), and rotation is performed. When the number increases and the efficiency gradually decreases from the maximum efficiency region, next, the number of turns of the stator winding is reduced (see FIG. 9).
(Characteristic of (b)) By bringing the efficiency close to the maximum efficiency region, the maximum efficiency region becomes wider with respect to the rotation speed as shown in FIG. 8, and the operation can always be performed near the maximum efficiency.

As described above, the PDU control unit 33 controls ON / OFF of each composite connection transistor according to the rotation speed of the motor to control the flow of the winding current, that is, the winding current of each winding. By switching the connection in series or in parallel, it is possible to always operate the motor near the maximum efficiency.

[0047]

As described above, according to the present invention,
A stator having a plurality of sets of stator windings wound on the same pole and a rotor having a plurality of poles magnetized are provided, and the plurality of stator windings are adapted to change the rotational speed of the rotor. The stator windings can be switched in series or in parallel, so that the maximum efficiency range for the rotation speed of the rotating electric machine is widened, and the maximum speed is always maintained regardless of the change in the rotation speed. This has the effect of enabling operation near efficiency. Further, the copper loss does not change before and after the switching of the stator winding, and there is no winding set through which no current flows, so that the stator winding can be used efficiently and effectively.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a DC brushless motor according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a conceptual diagram showing a winding pattern of a copper wire wound around each slot of a stator.

4 is a cross-sectional view taken along the line YY of FIG.

5 is a detailed view of a portion A in FIG.

FIG. 6 is an electric circuit diagram for controlling driving of the DC brushless motor of this embodiment.

FIG. 7 is a circuit diagram when two sets of stator windings are connected in series and in parallel.

FIG. 8 is an output characteristic diagram of the DC brushless motor of the present embodiment.

FIG. 9 is an output characteristic diagram of a conventional winding switching type rotary electric machine.

[Explanation of symbols]

 4 Stator 5 Rotor 33 PDU control unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keiichi Yamamoto Inventor Keiichi Yamamoto 1-4-1, Chuo, Wako-shi, Saitama, Ltd.

Claims (2)

[Claims] 1. A stator having a plurality of sets of stator windings wound on the same pole, and a rotor having a plurality of poles magnetized, wherein the plurality of stator windings are A winding switching type rotating electric machine characterized by being switchable according to changes in the number of rotations. 2. The winding-switching rotary electric machine according to claim 1, wherein the stator windings are switchable in series or in parallel.