JP2000116091A - Permanent magnet type synchronous motor and elevator apparatus using the same - Google Patents

Abstract

An object of the present invention is to provide a magnetic pole detecting means capable of determining the polarity without adding a new member to a rotor provided with a permanent magnet, without increasing the manufacturing process and labor. To get. The amplitude of a current flowing when a harmonic voltage is applied to a winding of a permanent magnet synchronous motor is compared, and when the amplitude is large, the winding is a pole made of an NdFB magnet having high conductivity. When the amplitude is small, the above problem is solved by determining that the winding faces a pole made of a ferrite magnet having low conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet synchronous motor, and more particularly to a permanent magnet synchronous motor suitable for being disposed in an elevator shaft and directly connected to a hoist. The present invention relates to a structure of an unnecessary permanent magnet synchronous motor.

[0002]

2. Description of the Related Art As a structure of a permanent magnet synchronous motor which does not require a magnetic pole detection sensor, as described in JP-A-9-56193, a conductive non-magnetic As a structure for forming a non-magnetic material layer made of a material, there is a structure in which a high-frequency voltage is applied to a stator winding and an eddy current generated in the non-magnetic material layer is detected to detect a magnetic pole position.

[0003]

In the prior art, it is necessary to form a conductive non-magnetic layer in addition to the permanent magnet, so that there are problems such as an increase in the number of steps for manufacturing the motor and an increase in labor. In addition, there is a problem in that the polarity cannot be determined because it is provided between the poles.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic pole detecting means which does not require a new member in a rotor provided with a permanent magnet, does not increase the manufacturing process and labor, and can determine the polarity. .

[0005]

SUMMARY OF THE INVENTION A permanent magnet type synchronous motor comprising a rotor provided with a permanent magnet and a stator provided with a winding, wherein one pole of the permanent magnet of the motor has high conductivity. A permanent magnet synchronous motor composed of a permanent magnet and the other pole composed of a permanent magnet having a low conductivity; in addition to this, a driving device for energizing the windings to rotate the motor; The driving device has a function of applying an electric signal to the winding and estimating a positional relationship between the rotor and the stator from an electric response to the electric signal. Using a ferrite magnet having a low conductivity as the other pole and comparing the amplitude of the current flowing when a harmonic voltage is applied to the winding, when the amplitude is large, the winding is conductive. Facing the pole made of NdFeB based magnet with high efficiency Determines that that, when the amplitude is small, by determining said winding faces the electrode made of low ferrite magnets conductivity, the problem is solved.

[0006]

FIG. 1 shows a permanent magnet synchronous motor according to an embodiment of the present invention. FIG. 1 is a sectional view of a permanent magnet synchronous motor according to an embodiment of the present invention.

FIG. 1 shows an example of an 8-pole, 6-slot permanent magnet synchronous motor. A permanent magnet is provided on the inner surface of the rotor 1,
The north pole 11 is made of a NdFeB permanent magnet, and the south pole 23 is made of a ferrite magnet. The stator 2 includes teeth 21 and coils 22 wound around the teeth. Here, the number of teeth is 6, and two coils for each phase are provided for three phases, for a total of six. When a current is applied to the coil 22 so that the teeth 21 have the N pole in the U-phase state of FIG.
Is attracted on the S pole side and repelled on the N pole side, so that a torque for rotating the rotor 1 clockwise is generated. Conversely, teeth 21
When an electric current is applied so as to be an S pole, a reverse torque is generated.

As described above, in the permanent magnet synchronous motor, the position of the N and S poles (magnetic pole position) of the permanent magnet is correctly determined because the position of the N and S poles of the permanent magnet is different depending on the positional relationship between the permanent magnet and the teeth and the direction of current supply. It is necessary to perform detection, and usually a dedicated magnetic pole detection sensor for detecting the angle of the magnetic pole is used.

In the present invention, since the N pole and the S pole are constituted by magnets having different electric conductivities, the magnetic pole can be equivalently detected by detecting the difference in electric conductivity without using a magnetic pole detecting sensor. . The principle will be described below with reference to FIGS.

FIG. 2 is a diagram in which the positional relationship between the teeth and the magnet is shifted from FIG. 1 for explaining the principle of magnetic pole detection according to the embodiment of the present invention. This is a state in which the centers of the U-phase teeth and the N-pole magnets coincide. At this time, when a high frequency voltage is applied to the U-phase coil, since the N pole is an NdFeB magnet, the conductivity is high, and an eddy current is generated in the magnet. For this reason, in the permanent magnet synchronous motor, the secondary resistance which is originally extremely large (and can be ignored) is equivalently reduced. Therefore, the high-frequency current flowing through the coil increases. on the other hand,
Contrary to the case of the figure, when the south pole faces the U phase,
Since the pole is a ferrite magnet, there is almost no conductivity and the eddy current is almost zero. Therefore, even when a high-frequency voltage is applied to the coil, the equivalent impedance is large and the high-frequency current is small.

FIG. 3 is a conceptual diagram of the U-phase high-frequency current due to the difference between the magnets described above. Section A is a case where the section faces the NdFeB magnet, and section B is a case where the section B faces the ferrite magnet. If this difference in current value is detected, a magnetic pole signal can be obtained. Hereinafter, a means for obtaining a magnetic pole signal will be specifically described with reference to FIGS.

FIG. 4 shows a circuit diagram of an embodiment of the present invention.
A portion surrounded by a dashed line in FIG. 4 is a magnetic pole detection unit that performs signal processing for magnetic pole detection. This part includes a high-frequency signal generator 66 and a current signal processing unit 72.

The description will be made in order from the current detection side in this configuration. A current detector 61 is provided in the U phase and the V phase of the stator coil 2 of the permanent magnet motor. The current detector 61 also calculates the W-phase current by the current calculator 62, and outputs the detected current values for three phases. This current value is calculated by the current control circuit (ACR)
The control is returned to 70, so-called motor current control is performed.
The current control of the permanent magnet synchronous motor is a well-known technique, which is out of the point of the present invention, and thus the description is omitted. However, the current value detected here is slightly different from the current value that generates the torque required by the ACR 70.

That is, the high frequency signal generated by the high frequency signal generator 66 is supplied to the inverter 6 via the gate drive circuit 71.
This is because, in addition to the transistor of the main circuit of No. 7, a current having a frequency much higher than the rated frequency of the motor for generating torque flows through the coil. Therefore, ACR
The current detection value is input to 70 via a low-pass filter 72. Thus, the influence of the high-frequency signal is removed from the current detection value, and only the component related to the torque is used for the current control.

Therefore, in the magnetic pole detecting section, contrary to the ACR 70, the band-pass filter 6 through which only the high-frequency signal passes is used.
Through 3, a current component corresponding to the motor torque and the number of rotations is removed. Further, from this output, the low-pass filter 6
In step 4, only the amplitude component of the high-frequency signal is extracted. When the waveform is shaped by the waveform shaper 65, a signal corresponding to the magnetic pole is obtained. This is added to the gate drive circuit 71, and thereby the timing of switching the energization of each phase of the current is set.

The inverter 67 converts the AC voltage of the power supply 69 into a full-wave rectified voltage via a rectifier 68 and shapes the DC voltage with a smoothing capacitor (not shown). The inverter 67 controls the current of the motor via the ACR 70, and the motor generates a desired torque. According to the present invention, the energization switching of the coils of each phase according to the position of the permanent magnet necessary for smoothly generating the torque is realized by the above-described means without using a magnetic pole detection sensor.

FIG. 5 shows a conceptual waveform of each part at the time of magnetic pole estimation using the circuit of FIG.

The magnetic pole position of each part in FIG. 1A is expressed as Hi when the magnetic pole faces the NdFeB-based magnet having high conductivity.

The U-phase high-frequency current waveform shown in FIG. 2B is obtained by extracting only the high-frequency component by the band-pass filter 63 from the waveform captured by the U-phase current detector 61 in FIG. Since this current waveform is also affected by the impedance of the V and W phases, the current waveform changes depending on whether the V and W phases face the NdFeB-based magnet or the ferrite-based magnet. It changes in four stages.

The U-phase high-frequency current demodulation waveform in (3) of FIG. 3 shows a waveform obtained by removing high-frequency components using 64 low-pass filters. It is equal to the envelope of the waveform of (2). Accordingly, when this is shaped at the level of the dashed line in the figure, the U-phase magnetic pole position estimation waveform in (4) of the figure is obtained. This is the output of the waveform shaping circuit 65 of FIG. This is equal to the magnetic pole position of the U phase in (1) of the original drawing, indicating that the magnetic pole can be detected. As described above, according to the embodiment of the present invention, the magnetic pole position can be estimated only by superimposing the high frequency on the current without using the magnetic pole detection sensor.

The waveform shaping of this embodiment is provided with a hysteresis characteristic so that it does not respond to a change in the high-frequency current demodulation waveform due to the influence of the eddy current of a phase other than the phase to be originally estimated. Can be increased. For example, even if the signal changes in sections A and E in FIG. 5 slightly exceed the shaping level, only the hysteresis width does not respond to the change, so that a correct magnetic pole signal can be obtained.

In the above embodiment, the change in the amplitude of the current due to the difference in the eddy current of the permanent magnet is used. However, the change in the phase of the current may be used. In addition, although the signal processing did not show a specific detailed configuration, ordinary hardware,
Alternatively, it can be sufficiently realized by software.

Hereinafter, an embodiment in which the present invention is applied to an elevator apparatus will be described with reference to FIGS.

FIG. 6 is a longitudinal sectional view of the permanent magnet synchronous motor according to the embodiment of the present invention. As described above, in the present embodiment, the cylindrical permanent magnet is adhered to the inner surface of the outer peripheral surface (hereinafter, referred to as a cylindrical portion) of the rotor 1 having a cylindrical shape and one circular surface opened, and the coil 22 is mounted. The wound stator 2 is provided facing the permanent magnet of the rotor 1, and the stator 2 is fixed to the motor frame 53 so as to have a predetermined gap with the permanent magnet of the rotor 1. One pole uses an NdFeB-based magnet, and the other pole uses a ferrite-based magnet. Further, the rotor 1 is rotatably held on a motor frame 53 by a bearing 52.

FIG. 8 shows an embodiment of an elevator using a motor according to the embodiment of the present invention.

A traction machine 40 in which the permanent magnet synchronous motor of FIG. 6 is directly connected to a sheave is disposed above a hoistway 41, and a rope 42 is hung on the sheave of the traction machine 40, and one end of the rope 42 is attached to a counterweight 43. The other end of the rope 42 is similarly fixed to the hoistway upper part 45 via a pulley 47 provided at the lower part of the car 46 via the pulley 44. The car 46 is guided by a car rail 48 so as not to shift in the horizontal direction, and the counter weight 43 is guided by a counter weight rail 49 so as not to shift in the horizontal direction.

Power is supplied to a permanent magnet synchronous motor and a brake (not shown) of the traction machine 40 by a control panel (not shown), and the operation thereof is controlled. The magnetic pole detection circuit shown in FIG. 4 is incorporated in the control panel, and the magnetic pole can be detected based on the presence or absence of the conductivity of the permanent magnet. Therefore, the permanent magnet synchronous motor does not have a position sensor for detecting magnetic poles. Even in such a configuration, the permanent magnet motor can arbitrarily generate torque by the control panel, thereby rotating the sheave and driving the rope to move the car up and down to the destination floor. The brake holds the sheave when the car stops and ensures that the car stops at the predetermined floor.

According to this embodiment, the traction machine 4
Since it is not necessary to provide a magnetic pole sensor in the permanent magnet synchronous motor of 0, the motor and the hoist can be reduced in size, so that the layout plan in the hoistway is easy, and the trouble of mounting the magnetic pole sensor can be omitted. There is an effect that the assembling of the hoist and the installation work of the elevator can be easily performed.

[0029]

According to the present invention, since the N pole and the S pole are constituted by magnets having different electric conductivities, a high frequency is superimposed on a voltage by detecting a difference in electric conductivity without using a position sensor. By simply doing so, the magnetic pole position can be estimated and the magnetic pole can be detected.

Also, by using the present invention in an elevator apparatus, it is not necessary to provide a magnetic pole sensor in the permanent magnet synchronous motor of the hoist, and the motor can be made smaller, so that the hoist can be made smaller. The layout plan is easy, and the trouble of mounting the magnetic pole sensor is eliminated.
In addition, there is an effect that the installation work of the elevator can be easily performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a permanent magnet motor according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the permanent magnet motor according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram of a high-frequency current according to the embodiment of the present invention.

FIG. 4 is a schematic diagram of a circuit configuration according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram of waveforms of respective parts at the time of magnetic pole estimation according to the embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of the permanent magnet synchronous motor according to the embodiment of the present invention.

FIG. 7 is an external view of an elevator apparatus according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... Stator, 11 ... High conductivity permanent magnet, 1
2 ... low conductivity permanent magnet, 21 ... core, 22 ... coil, 6
6 ... High frequency voltage generation.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tokuaki Hino 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Inside the Mito Plant of Hitachi, Ltd. (72) Noboru Arahori, Inventor No. 1070, Ma, Hitachinaka City, Ibaraki Prefecture Inside of the Mito Plant of Hitachi, Ltd. Mito Factory F-term (reference)

Claims (4)

[Claims] 1. A permanent magnet synchronous motor comprising a rotor provided with permanent magnets and a stator provided with windings, wherein one pole of the permanent magnets of the motor comprises a permanent magnet having high conductivity. Wherein the other pole is constituted by a permanent magnet having low conductivity. 2. A driving device for energizing a winding to rotate a motor, wherein the driving device applies an electric signal to the winding and determines a rotor and a stator from an electric response to the electric signal. 2. The permanent magnet type synchronous motor according to claim 1, further comprising a function of estimating a positional relationship of the permanent magnet type synchronous motor. 3. The amplitude of a current flowing when a harmonic voltage is applied to a winding is compared by using a high conductivity NdFeB-based magnet for one pole and a low conductivity ferrite magnet for the other pole. When the amplitude is large, it is determined that the winding faces the pole made of a high-conductivity NdFB-based magnet, and when the amplitude is small, the winding is a ferrite-based magnet having a low conductivity. 3. The permanent magnet synchronous motor according to claim 2, wherein it is determined that the motor faces a pole. 4. The permanent magnet synchronous motor according to claim 1, wherein a counterweight and a car are connected via a rope, and the rope is driven by a hoist, and the car is driven. The rotor of the motor has a permanent magnet, which is directly connected to a hoisting machine of a rope type elevator which is moved up and down, the rotor has a cylindrical shape, and the rotor is disposed outside a stator of the motor. An elevator apparatus using a permanent magnet type synchronous motor, wherein the elevator apparatus is an abduction type permanent magnet motor.