JPH10262359A - Permanent magnet dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the peak value of the induced voltage during a failure by setting the peak value of the generated induced voltage between terminals of a permanent magnet dynamo-electric machine to be the induced voltage value smaller than the peak value of the fundamental wave voltage. SOLUTION: A permanent magnet dynamo-electric machine device is provided with a DC power source 30, an inverter 31 to be connected thereto, and a permanent magnet dynamo-electric machine to be directly connected to the output end of the inverter 31, and of the system to control the magnetic field system by weakening the magnetic field of the permanent magnet dynamo-electric machine by a phase shift circuit 37. The shape of the induced voltage satisfies the inequality of Vp<Vp1 where Vp is the peak voltage of the induced voltage generated between the terminals of the permanent magnet dynamo-electric machine, and Vp1 is the peak value of its fundamental wave voltage. The peak value of the induced voltage during the failure is reduced to obtain the permanent magnet dynamo-electric machine which is compact in size, light in weight and high in torque, and a magnet dynamo-electric machine device provided with an inverter which can be handled with a switching element small in current capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet rotating electric machine, and more particularly, to a permanent magnet rotating electric machine having a small, lightweight, high-torque permanent magnet rotating electric machine, and an inverter having a switching element having a small current capacity. Is what you do.

[0002]

2. Description of the Related Art Driving motors used in electric vehicles, particularly electric vehicles, are limited in the amount of batteries loaded as electric vehicles, and it is necessary to secure a sufficient mileage for one charge. High efficiency is desired. On the other hand, a high torque is required for the acceleration performance of the vehicle, the highest speed, and the like, and a permanent magnet rotating electric machine suitable for the field weakening is required.

[0003] A permanent magnet rotating electric machine is effective as a motor suitable for the above conditions, and in particular, a permanent magnet rotating electric machine of a system that effectively generates reluctance torque utilizing the torque by the permanent magnet and saliency is effective. However, JP 2
-324232.

[0004]

According to the above prior art, a permanent magnet is arranged in a rotor core having a higher permeability than a permanent magnet, and is constituted by a permanent magnet and a rotor core in a circumferential direction. A configuration in which auxiliary magnetic poles are arranged side by side. On the other hand, the stator is a distributed winding stator and is configured to generate a smooth rotating magnetic field in synchronization with the rotation of the permanent magnet rotor.

[0005] By arranging the permanent magnet in the rotor core made of a magnetic material having a higher magnetic permeability than the permanent magnet, that is, by employing an internal magnet rotor configuration, a field weakening is possible, and high efficiency is achieved. In addition, operation up to the high-speed range is possible.

However, in a rotating electric machine that weakens a permanent magnet, if the inverter fails during high-speed operation, field weakening control becomes impossible, a high voltage is generated between the lines of the permanent magnet rotating electric machine, and large power is returned to the battery. Will be. This firstly causes sudden braking and instability of the posture of the traveling vehicle. Second, there is a problem in that the battery, the smoothing capacitor, the inverter and the like may be damaged.

Further, in the above prior art, since the ratio of the magnetic flux of the permanent magnet which contributes to the generation of torque is generally small, the induced voltage generated is suppressed to a relatively small value. However, the generated induced voltage at the highest speed is still very large. It will be.

Further, in the case of a permanent magnet motor of a distributed winding stator or the like, there is a case where the induced voltage jumps due to the slot ripple and becomes more serious.

In practice, in order to avoid the above, first, a method of inserting a contactor between the inverter and the rotating electric machine to disconnect the permanent magnet rotating electric machine from the inverter when a failure occurs, and secondly, setting the induced voltage low. There is a method, but in the first method, the space and weight of the contactor are a bottleneck, and the advantage over other electric motors, for example, induction motors, is lost. In the second point, the expected ratio of the reluctance torque component is large, and the result is that the physical size of the motor is increased, the current required to generate the torque is increased, and the current capacity of the inverter is unnecessarily increased. There are drawbacks that can occur.

The present invention reduces the peak value of the induced voltage at the time of a failure, thereby reducing the size and weight of the permanent magnet rotating electric machine with a high torque, and a permanent magnet rotating electric machine equipped with an inverter that requires only a switching element having a small current capacity. The purpose is to provide.

[0011]

SUMMARY OF THE INVENTION The present invention comprises a DC power supply,
In a permanent magnet rotating electric machine comprising: a permanent magnet rotating electric machine whose rotation speed is controlled by an inverter connected to the permanent magnet rotating machine; The peak value of the induced voltage is defined as Vp, and the peak value of the fundamental wave voltage is defined as Vp.
When it is set to 1, it is achieved by setting an induced voltage value of Vp <Vp1.

Preferably, Vm <Vp, where Vm is a voltage value at the center of the induced voltage between terminals of the permanent magnet rotating electric machine, and Vp is a peak value of the induced voltage.
Is achieved by setting the induced voltage value of

Preferably, the present invention is attained by making the coil width of the permanent magnet rotating electric machine substantially equal to the width of the magnetic pole of the permanent magnet rotor.

Preferably, the present invention is achieved by making the gap length at the center of the magnetic pole of the permanent magnet rotor larger than the gap length at the pole tip.

Preferably, the present invention is attained by arranging a plurality of stator salient poles on which stator windings belonging to the same phase are wound at electrically in-phase positions.

Preferably, the present invention has a constant torque range at a low rotation speed and a constant output operation range at a high speed, and the maximum rotation speed in the constant torque range is N1, and the maximum rotation speed in the constant output range is N2. Is achieved by N2 / N1 being 2 or more.

[0017]

Embodiments of the present invention will be described below.

FIG. 1 shows an embodiment of a permanent magnet rotating electric machine according to the present invention, FIG. 2 shows a structure of the permanent magnet rotating electric machine of the present invention, and FIG. 3 shows a sectional structure of the permanent magnet rotating electric machine of the present invention. .

2 and 3, the permanent magnet rotating electric machine comprises a stator 1 and a rotor 2. The stator 1 is composed of a laminated iron core and a stator winding 3 having a slot portion 11 interposed with an insulating material. Is wound. Here, the stator structure is a generally used distributed winding stator structure. For example, the stator core includes a yoke portion 1 that forms a magnetic circuit with the tooth portion 12.
The stator winding 3 is housed in the slot 11 from the slit 14 near the gap surface of the stator core.

The rotor 2 comprises a laminated core made of a magnetic material having high magnetic permeability, for example, a silicon steel plate, a permanent magnet 22 inserted into a permanent magnet insertion hole 21 provided in the laminated core, and the shaft 4. The laminated core made of the high magnetic permeability magnetic material includes an auxiliary magnetic pole portion 23 provided between the adjacent permanent magnets 22 and a magnetic pole piece portion 24 provided on the outer periphery of the permanent magnet 22.
And a yoke portion 13, in which a hole for passing the permanent magnet insertion hole 21 and the shaft 4 is punched. The rotation direction of the permanent magnet rotor 2 rotates counterclockwise and operates as an electric motor. Here, since the permanent magnet 22 to be used is a rectangular parallelepiped, dimensional accuracy is easily ensured as compared with an arc-shaped magnet, and the rotor can be used for high-speed rotation without a balancing operation of the rotor. Further, a neodymium magnet or the like, which is a high-performance magnet, is used as the permanent magnet 22.

FIG. 3 is a sectional structural view of a permanent magnet rotating electric machine according to the present invention. The stator 1 of the rotating electric machine includes a pair of housings 1.
0, 101 are fixed to the inner peripheral surface. Here, an example is shown in which the number of slots 11 of the stator core is 24, and the number of slots per phase is 1 for 8 poles of the permanent magnet rotor. The same applies even if this increases to a few.

The shaft 4 is rotatably held by the housings 10 and 101 via bearings 10a and 10b. Here, PS is a magnetic pole position detector for detecting the position of the permanent magnet 22 of the rotor 2, and E is an encoder for detecting the position of the rotor 2. The operation of the rotating electric machine is controlled via a control device by a signal from the magnetic pole position detector PS and an output signal from the encoder E. E is a position sensor for speed control.

FIG. 1 shows a control circuit of the permanent magnet rotating electric machine according to the present invention.

In the figure, a DC power supply 30 supplies power to a multi-phase stator winding 3 via an inverter 31.

The speed control circuit (ASR) 32 calculates a speed difference ωe from the speed command ωs and the actual speed ωf obtained from the position information θ from the encoder E via the F / V converter 33, A torque command, that is, a current command Is and a rotation angle θ1 of the rotor 2 are output by PI control (P: proportional term, I: integral term) and the like.

On the other hand, the sine wave / cosine wave generator 34 has a position detector PS for detecting the position of the permanent magnet magnetic pole of the rotor 2.
And a pulse from the encoder E, that is, the rotor position information θ, a sine wave output in phase with the induced voltage of each winding (here, three phases) of the stator winding 3 or a sine wave output phase-shifted as necessary Occurs.

The two-phase to three-phase conversion circuit 35 outputs current commands Isa, Isb, Isc to each phase according to the current command Is and the output of the sine and cosine wave generators 34. Each phase has a current control system (ACR) 36 individually, and sends a signal corresponding to the current commands Isa, Isb, Isc and the current detection signals Ifa, Ifb, Ifc from the current detector CT to the inverter 31, Control the current. in this case,
The combined current of each phase is perpendicular to the field magnetic flux or at a position shifted in phase (the combined magnetomotive force of each phase current is 90
A current is always formed by weakening the control to advance by more than one degree, thereby obtaining a commutator-free characteristic equivalent to that of a DC machine.

With the above configuration, the control device controls the combined vector of the armature magnetomotive force generated by the current flowing through the stator winding 3 so as to be directed to the rotation direction side from the center position of the auxiliary magnetic pole portion 23, thereby rotating the motor. The electric machine can generate a reluctance torque by the auxiliary magnetic pole part 23 in addition to the torque by the permanent magnet 22, and can operate as a high-torque motor.

According to the present invention, as shown in FIG. 1, the present invention comprises a DC power supply 30, an inverter 31 connected thereto, and a permanent magnet rotating electric machine directly connected to the output terminal of the inverter 31. In the permanent magnet rotating electric machine of the system in which the magnet rotating electric machine controls the field weakening by the phase shift circuit 37, the peak voltage of the induced voltage between the terminals of the permanent magnet rotating electric machine is Vp, and the peak value of the fundamental wave voltage is Vp1. In this case, the shape of the induced voltage is Vp <Vp1.

The torque characteristics required of a drive motor used for an electric vehicle such as an electric vehicle are such that a large torque can be generated at a low speed (a range up to a certain number of rotations), and in a high-speed region exceeding the range, the inverter 31 needs to operate at a high speed. It is desired that a constant output operation be possible within a range in which the capacity does not increase as much as possible. Therefore, at a low speed, a constant torque operation range within a range of the allowable current of the switching element of the inverter 31 and an operation at a high speed constant output range are generally performed.

The torque T of the permanent magnet motor is generally T = (E0０Iq + (Xq-Xd) ・ Id ・ Iq) / ω (1) where, E0: induced voltage ω: rotational angular velocity Id, Iq: d, q-axis current Xq, Xd: d, q-axis reactance In equation (1), the first term is a torque component by the permanent magnet 22,
The second term is a reluctance torque component by the auxiliary magnetic pole part 23.

In order to increase the torque, it is necessary to maximize the torque by the reluctance and the torque by the permanent magnet. Therefore, the method of increasing the induced voltage of the permanent magnet can reduce the current capacity of the switching element of the inverter 31.

On the other hand, since the output is constant in the high-speed range, the required torque is small, and neither the torque by reluctance nor the torque by the permanent magnet is in a phase in which the maximum torque can be generated for the same current. Here, the permanent magnet 2
The operation is performed by so-called field weakening control, which weakens the magnetic flux of No. 2 to lower the induced voltage by the permanent magnet. As a result, the voltage induced by the permanent magnet is reduced, so that the power is supplied from the DC power supply to a terminal voltage lower than the terminal voltage applied to the permanent magnet rotating electric machine, and the motor can be rotated up to a high speed.

If the induced voltage is increased by giving priority to low-speed torque under these conditions, it is necessary to increase the field weakening at high speed.

If the control device is operating normally, the induced voltage of the permanent magnet is reduced by the field weakening control.
1, but it does not exceed the range of the withstand voltage of the capacitor and the like provided between the input terminals of the inverter. However, it operates normally up to high-speed operation, and if the inverter breaks down, field weakening cannot be performed. Thus, a large induced voltage is directly applied to the inverter 31 and the capacitor, which may cause damage and return large power to the DC power source to cause a large braking force.

Therefore, in order to reduce the element capacity of the inverter, it is necessary to achieve the contradictory problems of generating a large torque and reducing the maximum value of the induced voltage. On the other hand, a slit 14 for accommodating the stator winding 3 in the slot portion 11 is generally provided in the stator core of the permanent magnet rotating electric machine as described above. The effect of this slit is
In the permanent magnet rotating electric machine having the auxiliary magnetic pole portion 23 that actively uses the reluctance torque as shown in FIG. 2, the waveform becomes as shown in FIG. 4A depending on the selection of the permanent magnet angle τ1. That is, the induced voltage waveform Vm = V at the center
p becomes large.

Considering the failure of the inverter 31 in the high-speed region with such a waveform, the withstand voltage of the elements and the capacitor of the inverter 31 is determined by the maximum value Vp of the induced voltage. There is a drawback that the effective value must be reduced, and therefore the current capacity of the inverter element must be increased in order to obtain the same torque.

According to the present invention, as a result of verifying the angle of the permanent magnet τ1 shown in FIG. 2 as a parameter, the induced voltage waveform changes as shown in FIGS. 4 (a), (b) and (c) depending on the angle. I found it.

FIG. 4 shows an example in which there are eight poles and 48 slots. The solid line indicates the induced voltage between lines, and the dashed line indicates the fundamental wave component.

FIG. 4A shows the angle of the permanent magnet τ1 and the pole node τ.
In the case where the ratio of p is 0.63, in this case, the maximum value Vp of the induced voltage of the rotating electric machine is equal to the value Vm at the center of the induced voltage, and the value is larger than the fundamental wave component Vp1 of the induced voltage. .

FIG. 4B shows the angle of the permanent magnet τ1 and the pole node τ.
In the case where the ratio of p is 0.58, the maximum value Vp of the induced voltage of the rotating electric machine is higher than the value Vm at the center of the induced voltage and smaller than the fundamental wave component Vp1 of the induced voltage.

FIG. 4C shows the angle of the permanent magnet τ1 and the pole node τ.
In the case where the ratio of p is 0.53, in this case, the maximum value Vp of the induced voltage of the rotating electric machine is larger than the value Vm at the center of the induced voltage and smaller than the fundamental wave component Vp1 of the induced voltage.

FIG. 4D shows Vp / Vp1 and Vm / Vp with respect to the ratio between the angle of the permanent magnet τ1 and the pole node τp.

Here, the fundamental wave component Vp1 of the induced voltage is directly related to the torque and is preferably large. On the other hand, it is desirable that the maximum value Vp of the induced voltage be as small as possible in order to operate until high speed. Therefore, it is required to reduce the ratio of Vp / Vp1. In FIG. 4D, the ratio between the angle of the permanent magnet τ1 and the pole node τp is 0.6 or less, that is, Vp
/ Vp1 is preferably 1.0 or less (Vp <Vp1). on the other hand,
Although the value Vm at the center of the induced voltage has no direct meaning, the above range and the range where Vm / Vp <1 correspond well as shown in FIG. 4D. That is, Vp <Vp1 is Vm
<Vp can be honored.

As described above, the current capacities of the inverter elements can be reduced by the arrangements shown in FIGS. 4B and 4C.

The above-described effect is obtained by having a constant torque range at a low rotation speed and a constant output operation range at a high speed, and setting the maximum rotation speed of the constant torque range to N1 and the maximum rotation speed of the constant output range to N2. Then, the larger the value of N2 / N1, the more effective. In other words, it is necessary to weaken the magnetic flux of the permanent magnet in a high speed range. Here, when the value is 2 or more, the above effect can be exhibited.

FIG. 5 shows another embodiment of the rotating electric machine of the permanent magnet rotating electric machine device of the present invention.

The same symbols as those in FIG. 2 indicate the same components. Here, too, the stator windings belonging to the same phase (eg U1, U2,
U3, U4) are electrically arranged in the same phase. With the same phase, harmonics of the induced voltage are generated in all the stator windings, so that they are not attenuated, and a trapezoidal induced voltage is easily generated.

In this embodiment, the gap of the pole piece 24 at the center of the permanent magnet rotor is increased. With the above shape, as shown in FIG. 5B, the induced voltage of the permanent magnet rotating electric machine becomes stair-like, and Vp <Vp1, and the same effect as that described in FIG. 4 can be obtained.

FIG. 6 shows another embodiment of the rotating electric machine of the permanent magnet rotating electric machine device of the present invention. The same symbols as those in FIG. 2 indicate the same components. Here, the stator of the permanent magnet rotating electric machine is characterized by being concentratedly wound. Also in this case, the stator winding is intensively wound, and the stator windings belonging to the same phase are all electrically arranged at the same phase position.

With the above configuration, even if the rotor has a configuration in which permanent magnets are arranged over almost the entire circumference, the induced voltage of the permanent magnet rotating electric machine can be stepped as shown in FIG. 5B. it can. Accordingly, Vp <Vp1 can be satisfied, and the same effect as that described with reference to FIG. 4 can be obtained.

When the above-described permanent magnet rotating electric machine is applied to an electric vehicle, particularly an electric vehicle, it is possible to mount a small, light and high-efficiency permanent magnet rotating electric machine driving device, and to provide an electric vehicle having a long charge traveling distance. Can be. In addition, a highly safe electric vehicle can be provided. In the above, a permanent magnet rotating electric machine having a speed control function (ASR) has been described as a control device, but the present invention is also applicable to a permanent magnet rotating electric machine having a torque control function. Further, as the rotating electric machine, any of a rotating electric machine having a gap in the axial direction, a generator, a motor, and an internal rotation type, an external rotation type, and a linear type can be applied.

[0053]

According to the above configuration, it is possible to provide a permanent magnet rotating electric machine including a small, lightweight, high-torque permanent magnet rotating electric machine and an inverter that requires only a switching element having a small current capacity.

[Brief description of the drawings]

FIG. 1 shows a permanent magnet rotating electric machine device of the present invention.

FIG. 2 shows a permanent magnet rotating electric machine of the present invention.

FIG. 3 shows a cross section of the permanent magnet rotating electric machine of the present invention.

FIG. 4 is a diagram illustrating the operation of an induced voltage waveform according to the present invention.

FIG. 5 shows another embodiment of the permanent magnet rotating electric machine of the present invention.

FIG. 6 shows another embodiment of the permanent magnet rotating electric machine of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Stator, 2 ... Rotor, 3 ... Stator winding, 11 ... Slot part, 12 ... Stator tooth part (salient pole part), 13 ... Stator yoke part, 21 ... Permanent magnet insertion hole, 22 ... Permanent magnet, 23
... Auxiliary magnetic pole part, 24 ... Magnetic pole piece part, 31 ... Inverter, 3
2: Speed control circuit (ASR), 33: F / V converter, 3
4: Sine wave and cosine wave generators 36: Current control system (AC
R), 35: a two-phase to three-phase conversion circuit, 37: a phase shift circuit.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Suetaro Shibukawa 2520 Oji Takaba, Hitachinaka-shi, Ibaraki Co., Ltd.Automotive Equipment Division, Hitachi, Ltd. Hitachi, Ltd. Automotive Equipment Division

Claims (6)

[Claims] 1. A permanent magnet rotating electric machine comprising: a DC power supply; a permanent magnet rotating electric machine whose rotation speed is controlled by an inverter connected to the DC power supply; and means for performing field weakening control on the permanent magnet rotating electric machine. A permanent magnet characterized in that, when a peak value of an induced induced voltage between terminals of a permanent magnet rotating electric machine is Vp and a peak value of a fundamental wave voltage thereof is Vp1, an induced voltage value of Vp <Vp1 is satisfied. Rotary electric machine. 2. A permanent magnet rotating electric machine comprising: a DC power supply; a permanent magnet rotating electric machine whose rotation speed is controlled by an inverter connected thereto; and means for weakening and controlling the field of the permanent magnet rotating electric machine. When the voltage value at the center of the induced electromotive force between the terminals of the magnet rotating electric machine is Vm, and the peak value of the induced electromotive voltage is Vp, the induced voltage value is such that Vm <Vp. Magnet rotating electric machine. 3. The permanent magnet rotary electric machine according to claim 2, wherein the coil width of the permanent magnet rotary electric machine is substantially equal to the width of the magnetic pole of the permanent magnet rotor. 4. The permanent magnet rotating electrical machine according to claim 1, wherein the gap length at the center of the magnetic pole of the permanent magnet rotor is larger than the gap length at the pole tip. 5. The permanent magnet according to claim 1, wherein a plurality of stator salient poles wound with stator windings belonging to the same phase are all electrically in-phase. Magnet rotating electric machine. 6. A constant torque range having a constant torque range at a low rotation speed and a constant output operation range at a high speed, wherein the maximum rotation speed in the constant torque range is N1 and the maximum rotation speed in the constant output range. A permanent magnet rotating electrical machine, wherein N2 / N1 is 2 or more, where N2 is the number of revolutions.