JP2001298982A - Motor drive, and motor unit comprising it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the efficiency of a motor having permanent magnets. SOLUTION: The motor drive 50 being connected with a motor 42 comprising windings 31, 32, 33 and permanent magnets 34-41 comprises a power supply means 51 for supplying a current having a waveform substantially similar to that of a no-load induction power of the motor 42. Effective value of the current can thereby be suppressed as much as possible with respect to torque being generated and high efficient operation of the motor 42 can be realized while reducing copper loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive device which performs a rotary motion and is used in homes, factories, offices, stores, transportation, etc., and a washing machine, a refrigerator, an air conditioner and a ventilation fan using the same. The present invention relates to an electric device such as

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 62-1 is an example of the prior art.
As shown in the circuit diagram of FIG. 12 and the cross-sectional view of the electric motor of FIG. 13, the electric motor shown in Japanese Patent No. 41998 has a permanent magnet provided on the rotor 2 of the three-phase electric motor. In addition, when the rotor 2 rotates, sinusoidal voltages of the induced voltages EA to EC are induced in the stator windings 1A to 1C.

The stator windings 1A to 1A are provided on the stator side.
Apart from C, the detection windings 3A to 3C are wound,
The detection windings 3A to 3C are arranged such that the induced voltage induced by the detection windings 3A to 3C has the same phase as the phase induced voltage of the stator windings 1A to 1C.

Further, a starting circuit 10, a PLL circuit 9, current detectors 4A to 4C, amplifiers 5A to 5C, and adders 6A to 6
C, and multipliers 7A to 7C.

In the above configuration, after the start-up is performed by the output of the starting circuit 10, the waveform of the winding current of the stator of the motor and the waveform of the induced voltage of the detection winding are controlled to be similar. It was characterized.

Then, while simplifying the circuit configuration of the detecting section, a current waveform is generated, and driving with small pulsating torque and small speed fluctuation is performed.

[0007]

In the above prior art, there is a first problem that it is necessary to provide a detection winding in the motor, which complicates the structure of the motor.

Particularly, in order to obtain the same voltage waveform as that of the induced electromotive force generated in the stator winding, the sectional shape of the iron core on which the detection winding is provided is determined by the stator winding. It is almost the same shape as the iron core that is used, and since the permanent magnet on the rotor side acting on the detection winding also needs to have the same characteristics as the part where the stator winding faces, Although the thickness of the copper wire for the detection winding need only be extremely thin, the axial length of the rotation is considerably increased as a result, and the weight and cost are also increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and has a structure of a simple motor having no detection winding, and efficiently supplies only a current related to torque generation. By performing the operation under the condition of high efficiency, energy saving and reduction of heat generation of the electric motor are realized.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a motor connected to a motor having a winding and a permanent magnet, and generating a current having a waveform substantially similar to a no-load induced electromotive force waveform of the motor. This constitutes a motor drive device having power supply means for supplying the electric motor.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is an electric power supply device for connecting a motor having a winding and a permanent magnet and supplying a current having a waveform substantially similar to a no-load induced electromotive force waveform of the motor to the motor. It has a supply means, and aims to improve the efficiency by minimizing the effective value of the current with respect to the generated torque and reducing the copper loss.

The second aspect of the present invention is particularly configured such that DC to AC conversion is performed as the power supply means, and a DC power supply such as a battery is used to reduce the effective value of the current with respect to the generated torque as much as possible. By suppressing and reducing the copper loss, the motor can be operated with high efficiency.

According to a third aspect of the present invention, in particular, an AC power source having a constant frequency is received and AC to AC conversion is performed. For example, an AC power source such as a 100 V 60 Hz commercial power source is used. Further, the present invention makes it possible to operate the motor with high efficiency by minimizing the effective value of the current with respect to the generated torque and reducing the copper loss.

According to the present invention, the electric angle of the energizing section is 120 degrees, and the effective value of the current with respect to the generated torque is reduced as much as possible with a relatively simple structure. This makes it possible to operate the three-phase motor with high efficiency by suppressing the copper loss.

According to a fifth aspect of the present invention, the electric angle of the energized section is set to 120 to 145 degrees, and the effective value of the current with respect to the generated torque is suppressed as much as possible to reduce the copper loss. This makes it possible to operate a three-phase motor with high efficiency.

According to a sixth aspect of the present invention, the absolute value of the difference between the fifth harmonic rate of the winding current waveform and the fifth harmonic rate of the no-load induced electromotive force is set to 10% or less. In addition, the effective value of the current with respect to the generated torque is substantially minimized, the copper loss is sufficiently reduced, and the motor can be operated with high efficiency.

According to a seventh aspect of the present invention, in particular, the absolute value of the difference between the waveform ratio of the winding current waveform and the waveform ratio of the no-load induced electromotive force is 0.1 or less, It is intended to minimize the effective value of the current with respect to the generated torque, sufficiently reduce the copper loss, and operate the motor with high efficiency.

According to an eighth aspect of the present invention, there is provided an electric motor provided with an electric motor having a winding and a permanent magnet, wherein the effective value of the current with respect to the generated torque is suppressed as much as possible, the copper loss is reduced, and the electric motor is provided. This realizes reduction of heat generation of the motor and energy saving of the device by the high-efficiency operation.

According to a ninth aspect of the present invention, in particular, a three-phase star connection is used, and three-phase power is supplied to the motor, so that the motor driving device operates stably with a relatively simple configuration. While realizing the motor and the motor, the effective value of the current with respect to the generated torque is suppressed as much as possible, the copper loss is reduced, the heat generation of the motor is reduced by the high-efficiency operation of the motor, and the energy saving of the device is realized.

According to a tenth aspect of the present invention, in particular, a concentrated winding structure is provided, in which winding resistance is reduced, copper loss is further reduced, and heat generation of the motor is reduced by high efficiency operation of the motor. Energy saving is realized more effectively.

According to an eleventh aspect of the present invention, in particular, the ratio of the number of poles to the number of lots is two to three, the winding resistance is suppressed, and the no-load induced electromotive force and current waveforms are reduced. By making it possible to make the shape closer to a similar shape, copper loss is further reduced, and heat generation of the motor is reduced and energy saving of the device is more effectively realized by high efficiency operation of the motor.

[0022]

Next, specific examples of the present invention will be described.

(Embodiment 1) FIG.
6 is a circuit diagram of an electric device 30 according to an embodiment of the invention described in 6, 7 to 11. FIG.

In FIG. 1, a three-phase motor 42 having a U-phase winding 31, a V-phase winding 32, a W-phase winding 33, and permanent magnets 34 to 41 is provided.

The windings 31 to 33 have a three-phase star connection, and furthermore, in this embodiment, hall ICs 43 to 45 for position detection are provided.

Motor drive unit 5 connected to motor 42
0 has a power supply means 51 for supplying a current having a waveform substantially similar to the no-load induced electromotive force waveform of the motor 42 to the motor 42.

In this embodiment, the power supply means 51 includes switching elements 52 to 57 formed by connecting an IGBT using a silicon semiconductor and a rectifying element in parallel, and a control circuit for controlling conduction and non-conduction of these switching elements. 58.

However, the type of the switching element is IGB
The use of T is not an absolute condition. For example, a MOSFET, a bipolar type, a DGMOS, a GTO, or the like may be used, and germanium, silicon carbide (SiC), or the like may be used other than silicon.

The AC power supply 60 is a commercial power supply having an effective value of 100 volts and a constant frequency (60 Hz or the like).
The motor driving device 50 receives the AC power supply 60, and is rectified by a choke coil 61, rectifying elements 62 and 63, and electrolytic capacitors 64 and 65 in a double voltage (double voltage) manner. It supplies a DC voltage of volts.

However, double voltage rectification is only one example of the configuration for converting AC to DC, and full-wave rectification or the like may be used.

Although the rectifying elements 66 and 67 have the function of preventing the reverse voltage from being applied to the capacitors 64 and 65, a configuration in which four rectifying elements are connected as in this embodiment. In the case of (1), a bridge type rectifier of a silicon semiconductor generally used can be used, and it can be configured with a small number of parts.

However, the four rectifying elements are other than silicon, for example, germanium, silicon carbide (SiC),
It can also be configured as a rectifying element using selenium or the like.

FIG. 2 is a detailed configuration diagram of the electric motor 42 according to the first embodiment.

The electric motor 42 comprises a stator 70 and a rotor 71. The stator 70 is made of a silicon steel sheet having a thickness of 0.5 mm.
An iron core 72 formed by stacking zero sheets, and coils 73a to 73l
have.

The shape of the iron core 72 has twelve slots 74.
a-74l and twelve teeth 75a-75l, and each coil is wound around each tooth.

On the other hand, the rotor 71 has eight permanent magnets 34 to 41 bonded to the surface of an iron core 76 which is made of forged iron and also functions as a magnetic path, and applies torque while rotating about a shaft 77. The power is transmitted to various mechanical loads (not shown) to supply power.

The mechanical load includes a stirring blade and a dewatering tub when used as a washing machine, a fan when used as a ventilation fan and a vacuum cleaner, and a compressor when used as an air conditioner and a refrigerator. However, there may be other uses (dishwasher, etc.).

Here, the permanent magnets 34, 36, 38, 40
Has an N pole on the outside, that is, the surface facing the stator 70, and the permanent magnets 35, 37, 39, 41 have an S pole on the outside, that is, the surface facing the stator 70. Of the rotor 71 is realized.

Therefore, in this embodiment, the ratio between the number of poles and the number of slots is 8:12, that is, approximately 2/3.

FIG. 3 shows the winding 3 of the electric motor 42 according to the first embodiment.
FIG. 4 is a connection diagram showing a configuration of 1, 32, and 33, and each winding is configured by a series circuit of four coils.

That is, the U-phase winding 31 is
a, 73d, 73g, 73j, the V-phase winding 32 is constituted by a series circuit of coils 73b, 73e, 73h, 73k, and the W-phase winding 33 is constituted by coils 73c, 73f, 73i, 73l. Is what it is.

Here, a black circle attached to one side of each coil indicates the polarity, and when a current flows from the side with the black circle, each coil is placed inside each tooth, that is, the rotor 71. Is wound so that an N pole is generated on the side opposite to.

Therefore, for example, when a current is supplied from the U terminal, the magnetomotive force generated by the four coils constituting the winding 31 becomes the same polarity (N pole) at the position shifted by 90 degrees in FIG. , Operate as an 8-pole machine.

The winding method in which one pole is formed by one coil as described above is generally called concentrated winding. In the present embodiment, the concentrated winding is performed by setting the width of each coil to an electrical angle of 120 degrees. The so-called coil end length of the copper wire can be shortened, the electric resistance of the copper wire can be reduced, and the effect of suppressing copper loss can be obtained. At the same time, the shape and weight of the motor can be reduced, and the cost can be reduced. Not only can it be reduced, but it can also contribute to the effective use of resources and the protection of the global environment.

As a manufacturing advantage in the case of concentrated winding as in this embodiment, an iron core 72 called a split core or the like is manufactured by dividing it into twelve cores.
７３73 liters, and one stator 70 by welding or the like.
It is also possible to adopt a manufacturing method in which the net cross-sectional area of the copper wire with respect to the area of the slots 74a to 74l, that is, the so-called copper space factor, can be remarkably improved. It also has the effect of contributing to improved performance such as reduction.

The configuration of the motor in which the ratio of the number of poles to the number of slots is 2 to 3 may be 6 poles 9 slots, 4 poles 6 slots, etc. in addition to the 8 poles 12 slots of this embodiment. In the case of a device in which vibration does not cause a problem even with three poles, an advantageous configuration may be used.

FIG. 4 is an operation waveform diagram of the control circuit 58 of the first embodiment, and FIG.
FIG. 4A is a waveform diagram of the input signal S1 from the C43, FIG. 4A is a waveform diagram of the input signal S2 from the Hall IC 44, and FIG.
Shows a waveform diagram of the input signal S3 from the Hall IC 45, and the horizontal axis shows time converted into an electrical angle.

The electrical angle is generally a value obtained by multiplying half of the number of poles by a mechanical angle. In this embodiment, since the motor 42 has eight poles, a mechanical angle of 90 degrees corresponds to an electrical angle of 360 degrees. It will be.

In this embodiment, rotation is performed in the rotation direction indicated by the arrow in FIG. 2, that is, clockwise, and signals are output from the three Hall ICs in the phase sequence of S3, S2, and S1. You.

Each of the Hall ICs 43, 44 and 45 outputs a high signal when the pole of the facing permanent magnet is the N pole,
If it is the south pole, the low signal is sent to the position detection signals S1, S
2, and output as S3.

S2 has a waveform advanced by 120 degrees in electrical angle with respect to S1, and S3 has a waveform advanced by 120 degrees in electrical angle with respect to S2.

Then, S1, S2, S every 60 electrical degrees
Since the logic of any one of the three signals changes, the combination of the output logics of the Hall ICs 43, 44, and 45 changes sequentially every electrical angle of 60 degrees.

FIG. 4D shows the gate signal U of the switching element 52.
FIG. 4E shows a gate signal VP of the switching element 53.
4 (f) is a waveform of the gate signal WP of the switching element 54, FIG. 4 (g) is a waveform of the gate signal UN of the switching element 55, and FIG. FIG. 4K shows the waveform of the gate signal WN of the switching element 57.

Regarding the gate signal of any of the switching elements, pulse width modulation with a carrier frequency of 15.625 kHz is applied to the first half of the section with an electrical angle of 60 degrees, and the ON signal is applied to the second half of the section with an electrical angle of 60 degrees. It is output continuously,
The electrical angle of 120 degrees, which is the sum of the first half and the second half, is defined as an energized section.

In this embodiment, the timings t1, t2, t3... At which the combination of the output logics of the Hall ICs 43, 44, and 45 generated every electrical angle of 60 degrees change. . . . On the other hand, the on / off control is advanced for a period corresponding to the electrical angle of 10 degrees.

FIG. 5 shows signals Up,
It shows the on-time ratio of pulse width modulation in the first half electrical angle section of Vp, Wp, Un, Vn, and Wn, that is, a change in duty.

In this embodiment, at the beginning of the section of 60 electrical degrees where pulse width modulation is performed, 48%
After that, the timer inside the control circuit 58 performs an operation to reduce the duty value by a simple function (for example, a linear function) with respect to time, and the duty is reduced linearly.

After the duty value becomes 33% at an electrical angle of 11 degrees from the start, the electrical angle is maintained at a constant value of 33% and continues up to the electrical angle of 60 degrees.

As described above, when the control for decreasing the duty value linearly with time is performed, the control circuit 5
8 is small, the signal from the Hall ICs 43, 44, and 45 is converted into higher resolution by means of storing the change in duty as a time function or by a configuration such as a PLL to estimate the electrical angle. Then, it is of course possible to realize a configuration in which the duty values stored as a function of the electrical angle are sequentially read out from a ROM table or the like and control is performed, but it can be sufficiently realized without necessarily taking such a configuration. Things.

6A shows a current waveform of the current Iu supplied to the U-phase winding 31 of the motor 42, and FIG. 6A shows a waveform of the no-load induced electromotive force Eu at both ends of the winding 31. FIG. 3 is a diagram showing the no-load induced electromotive force Eu observed by connecting an oscilloscope probe between the U terminal and the N terminal in FIG. 3 in a state where the motor 42 is externally rotated by, for example, another motor. , U terminal side is shown as plus.

The waveform of the no-load induced electromotive force depends on the specifications of the windings 31, 32, 33 of the
It varies depending on the magnetization distribution of 4 to 41, etc.
Generally, the waveform has a distortion.

Since the three phases are equal, the phases of the V and W phases are shifted by 120 degrees, but the waveforms are completely equivalent to the U phase.

It should be noted that the N terminal is temporarily provided for observation with an oscilloscope, and in this embodiment, it is not necessary to connect it to any part during actual operation.

Incidentally, when the no-load induced electromotive force between the lines between the U terminal and the V terminal is observed without using the N terminal,
The waveform of FIG. 6A is shifted by an electrical angle of 60 degrees and added together to form a stepped waveform, which is significantly different from FIG. 6A.

Note that the broken line in FIG.
This is a current waveform when the motor is operated at a constant value of 5% and without an advance angle of 10 degrees electrical angle (advance angle = 0). The waveforms indicated by solid lines are the same under both torque and speed conditions. ,
Comparing the solid-line waveform of FIG. 6A with the broken-line waveform, the solid-line waveform is closer to the waveform of FIG.

As is well known, in the case of a motor having a permanent magnet and a winding, the instantaneous value of the product of torque and speed (mechanical output power) generated by the so-called Fleming's left-hand rule is expressed by the no-load induced electromotive force and the current. However, according to the study by the present inventors, under the condition that the current waveform is completely similar to the no-load induced electromotive force waveform and the phase is also in-phase, a constant mechanical output power is obtained. The effective value of the current required for obtaining the minimum value can be obtained.

Therefore, a constant mechanical output power, that is, a constant torque at a constant speed can be obtained by a motor drive device capable of supplying a current having a waveform close to the no-load induced electromotive force waveform to the motor 42 as in the present embodiment. In addition, the effective value of the required current can be made closer to the minimum value.

The no-load induced electromotive force waveform of U in this embodiment is substantially expressed by the following equation.

Eu = Asin (wt) + Bsin (5w
t + θ5) + Csin (7wt + θ7) In the above equation, A is the amplitude of the fundamental wave, B is the amplitude of the fifth harmonic, and w is the electrical angular velocity.

Further, t has the origin at the time of the zero point of the U-phase fundamental wave, and the V-phase and W-phase waveforms having the same shape are shifted by an electrical angle of 120 °.

The electric motor 42 of this embodiment has an electrical angle of 120 °
And the ratio of the number of poles to the number of slots is 2: 3, the fifth harmonic of the no-load induced electromotive force waveform is θ5 = θ7 = 180 ° with respect to the fundamental wave.
Has the following phase difference.

In the first embodiment, the lead angle of 10 electrical degrees and the
The fifth harmonic ratio of the current of the winding is set to 4% by the change of the duty shown in FIG.

Here, the fifth harmonic rate is defined as a value obtained by dividing the amplitude of the fifth harmonic by the amplitude of the fundamental wave (B / A) in percent.

On the other hand, the no-load induced electromotive force
The harmonic ratio is 12%, and the absolute value of the difference between the above-mentioned current and the fifth harmonic ratio of 4% is 8%, which is 10% or less.

In this embodiment, for the third harmonic, the current waveform and the no-load induced electromotive force waveform are almost zero, and the seventh harmonic rate (C / C
Since A) was 3% or less, the characteristics of the waveform were substantially determined by the fifth harmonic rate.
Discussions on harmonic rates will be extremely effective.

The fifth harmonic of the current waveform Iu is θ5
Has a phase difference of 180 °.

In the first embodiment, the waveform ratio of the current of the winding is 0.10.

The waveform ratio is a value obtained by dividing the effective value by an average value during a half cycle from the zero point to the zero point of the waveform.
The waveform ratio of the no-load induced electromotive force is 0.17.

Therefore, the absolute value of the difference between the two waveform ratios is 0.07, which is 0.1 or less.

In the first embodiment, the phase difference between the fundamental wave of the winding current and the fundamental wave of the no-load induced electromotive force is 6 electrical degrees.

According to experiments by the inventors, the absolute value of the difference between the fifth harmonic rate of the winding current waveform and the fifth harmonic rate of the no-load induced electromotive force waveform is 10% or less. When the condition of No. 6 is satisfied, the efficiency of the electric motor 42 is improved.

In the case where the absolute value of the difference between the waveform ratio of the winding current waveform and the waveform ratio of the no-load induced electromotive force waveform is 0.1 or less, the high efficiency of the motor 42 is improved. Was realized.

The value of the no-load induced electromotive force changes in proportion to the speed of rotation, and is inversely proportional to the speed during one cycle.
The waveform is almost equal to the waveform of (a).

When the duty is finely adjusted in order to perform speed control for keeping the speed control of the electric motor 42 constant, the duty characteristic shown in FIG. %), The characteristic curve of the torque and the speed of the electric motor 42 moves, so that the speed can be maintained even when the load fluctuates.

The losses (copper losses) of the windings 31, 32, 33 are as follows:
It is known that the value of the electric resistance is multiplied by the square of the effective value of the current. However, by reducing the effective value of the current, the copper loss can be reduced, and the electric motor 42 has a high efficiency. It becomes possible to drive.

In particular, the dehydration tank was operated at a speed of about 150 r / min,
When used in a washing machine that directly drives with a torque of 4.7 Nm and uses a centrifugal force to wash clothes, the operating point is low-speed and high-torque. However, when the present embodiment is used under such operating conditions, as shown by the broken line in FIG. 6A, the energizing section 120 in which the advance angle is not performed and the duty is not changed is performed. As compared with the conventional operation method, the effect of improving the efficiency of the electric motor is high, and the power consumption of the electric device can be reduced by 10% or more.

In addition, the maximum value (peak value) of the current of the winding at the above operating point is also reduced by about 18% in the control method of the present embodiment shown by the solid line in FIG. Therefore, the efficiency of the motor drive device 50 can be improved by reducing the current rating of each switching element or reducing the loss of the switching element.
There is also an effect of preventing demagnetization of the permanent magnets 34 to 41.

Generally, in a motor using a permanent magnet, when the peak value of the winding current exceeds the limit value, irreversible demagnetization occurs, and thereafter the performance of the device deteriorates. If the peak value of the current at the same torque needs to be small as described above, such a problem can be prevented.

A means for separately detecting the peak current value of the winding and limiting or interrupting the current when the peak current value reaches a predetermined value is provided in the motor driving device 50 to prevent the problem of demagnetization. Even in the case of the configuration, by using the method of the present invention, the predetermined value can be kept low, and the material of the permanent magnets 34 to 41 in the electric motor 42 can be low cost or thin. Thus, the effect of reducing the cost of the apparatus can be obtained.

Conversely, if the peak current value is unchanged,
Operation under a condition with a larger torque is also possible. For example, in the above-described washing machine using centrifugal force, an effect is obtained in which persistent clothing dirt can be removed in a shorter time.

According to an experiment by the inventors, when the currents of the windings 31, 32, and 33 are set to be sine waves with respect to the motor 42 used in this embodiment, the peak of the winding current at the same torque is obtained. The value is also higher than the solid line in FIG. 6 (a), and when the current waveform of the winding is a sine wave even in a high-speed region, the specification of the motor is changed such that the number of windings is reduced. It has been found that when this is performed, the current value of the winding at a low speed is further increased, and the peak current value of the switching element is increased.

In addition, the teeth 75 a to 75
The magnetic flux density of the portion also has the property of becoming saturated when the peak value of the current of the windings 31, 32, and 33 is large. If the peak current is suppressed, a margin for the saturation is increased to reduce the noise. In addition, teeth 75a-l
It is also possible to change the specification of the electric motor 42 such that the width of the motor 42 is reduced, thereby increasing the effect of reducing the amount of iron and the length of the copper wire.

In the present embodiment, the electrical angle of 60 degrees in the first half of each switching element is pulse width-modulated, and the electrical angle of 60 degrees in the second half is changed.
The electrical angle is controlled to be in the ON state.
Immediately after the switching of the switching element, which is generated every 0 degrees, it is possible to obtain the effect that the noise caused by the jump of the voltage between both ends of each winding and the rapid change of the winding current can be suppressed. It is not necessary to perform a simple control. For example, the switching elements 52, 53, and 54 on the high-potential side are changed with respect to both the first half electrical angle 60 degrees and the second half electrical angle 60 degrees as shown in FIG. The control may be such that the open / close elements 55, 56, and 57 on the low potential side continue to be in the ON state over the 120 electrical angle section.

In any case, setting the energizing section to 120 degrees means that three Hall ICs 43 and
In the case of performing position detection using 44 and 45, the energizing section is just twice as large as the electrical angle of 60 degrees, which is the interval between the rising and falling edges of the output signal of each Hall IC. The on / off control of each switching element can be controlled by simple logic, and it can be used for a device requiring a large starting torque, such as a washing machine, and can drive a three-phase motor stably. is there.

Also, unlike a power unit used for a compressor used in an air conditioner, a refrigerator, or the like, a Hall IC is not used, and the waveform of the induced electromotive force of the motor in a section other than the energization period is converted to a terminal of the motor, that is, the motor drive. In the case of detecting the position of the rotor by detecting the voltage of the output of the device, the electric angle 60
Since there is a period during which both the upper and lower switching elements are controlled to be off, the position detection operation can be sufficiently performed within that period, and therefore, the wiring for the output signal is also provided without the Hall IC. It is also possible to drive the vehicle while detecting the position without detecting the position.

The motor 42 used in the present embodiment has a winding 3
Since all of 1, 32 and 33 are formed by concentrated winding and the ratio of the number of poles to the number of slots is 2 to 3, the coil 73
a to 73l have an electrical angle of 120 degrees, and when the permanent magnets 34 to 41 are uniformly magnetized, the windings 31, 3
The sections in which both the no-load induced electromotive forces 2 and 33 are generated have an electrical angle of 120 degrees.

Therefore, when the energizing section is set to 120 degrees, the no-load induced electromotive force is low in the remaining section of 60 degrees, so that torque generation is small even when the current of the winding passes through that section. There is little hindrance to the purpose of performing efficient motor operation.

However, even if the motor is not configured to have three phases, as long as a current substantially similar to the no-load induced electromotive force waveform described in claim 1 is supplied to the motor, the motor may be used. The effect that the effective value of the current necessary to obtain the same torque can be made almost the minimum value can be improved, and energy saving by increasing the efficiency of the motor and reduction of heat generation of the motor can be realized. Becomes

Further, since the motor 42 of the present embodiment has the three-phase windings 31, 32, and 33 connected in a star connection, the current flowing through each winding can be controlled by the switching element on the high potential side or the switching element on the low potential side. And the current of the winding can be controlled almost directly by the on / off operation of these switching elements.

On the other hand, for example, in the case of a motor configuration in which a delta connection is made even for the same three phases, a current component circulating through three windings connected in a ring (3nth harmonic component) , Where n is an integer), and since a plurality of winding currents flow from one switching element, it is difficult to control the current waveform of each winding.

Therefore, the star connection is extremely effective in controlling the current waveform of the winding, as compared with the delta connection.

In the first embodiment, with the above-described motor configuration, no load is applied only by the advance angle and the linear duty change as shown in FIG. 5 without using a storage means or the like for finely storing the duty change waveform. A winding current waveform sufficiently close to the induced electromotive force waveform is realized, and high-efficiency driving of the electric motor 42 can be realized.

The means for realizing the advance angle can be realized by, for example, shifting the position of a position detection sensor such as a Hall IC, in addition to the configuration in which electrical control is performed in the control circuit. It is effective in some cases as long as it performs a rotational motion in only one direction, such as an electric motor for driving a fan.

However, if the operating conditions of the motor 42 determined by the torque and the speed are different, it is better to change the duty change waveform and the amount of advance angle to make the winding current closer to the no-load induced electromotive force waveform. Since it can be made into a waveform, in order to ensure the effect of high efficiency under multiple load conditions, depending on the value of speed or current,
A greater effect can be obtained by adding a configuration such as changing them. (Embodiment 2) FIG. 7 shows an operation waveform diagram of an electric motor driving device according to an embodiment of the present invention. Also in FIG. 7, an electric motor driving device and an electric motor are shown. Is realized by a circuit diagram completely equivalent to that of FIG. 1 showing the first embodiment, and only the operation of the control circuit 58 is different.

In the second embodiment, the switching elements 52 to 57
, The sum of the period during which pulse width modulation is applied and the period during which the ON state is maintained is 140 degrees in electrical angle, and this section is defined as an energizing section in which current is supplied to the winding. Therefore, the electric angle of the energizing section described in claim 5 is 120 degrees to 145 degrees.

In this embodiment, each of the switching elements is controlled so as to keep the ON state in a section having an electrical angle of 60 degrees, whereby the U, U of the three-phase windings 31, 32, 33 are controlled.
One of the V and W terminals is always fixed to the potential of the terminal on the high potential side of the capacitor 64 or the terminal on the low potential side of the capacitor 65. However, it is not absolutely necessary to fix the potential of one terminal, and it is sufficient that the energizing section is larger than the electrical angle of 120 degrees and smaller than 145 degrees.

FIG. 8A shows the U-phase winding 3 of the electric motor 42.
6 (a) shows a waveform diagram of the no-load induced electromotive force Eu at both ends of the winding 31. FIG.

In the second embodiment, the energized section has an electrical angle of 140 degrees, which is 20 degrees larger than in the first embodiment.
The current waveform of the winding 31 can be made closer to the no-load induced electromotive force waveform shown in FIG.
The effect of improving the efficiency of Example 2 is greater than that of Example 1.

However, the work to be performed by the control circuit 58 is slightly more than that in the first embodiment, and it is necessary, for example, to make the microcomputer or the like slightly more capable.

Further, since it is possible to prevent the current waveform of the winding from being smooth, that is, to prevent the temporal change of the current from being excessive, the noise can be reduced.

In this embodiment, when comparing (A) and (D) in FIG. 7, for example, the period during which both the high-potential side and the low-potential side switching elements are off is before or after the energizing section. There is an angle of 40 degrees each, and during this period, the position can be detected from the terminal voltage of the electric motor 42 as a method of detecting the position.

Therefore, even when applied for driving a compressor such as a refrigerator or an air conditioner, for example, only three-phase three-wire wiring is connected between the motor and the motor driving device without using a Hall IC or the like. Thus, the motor can be operated with high efficiency.

Also, in a device other than the compressor load,
Effects such as reduction in cost of the apparatus can be obtained.

According to the experiments by the inventors, the period during which both the high-potential side and low-potential side switching elements are off is an electrical angle of 35.
It was confirmed that the position detection method using the Hall IC as described above can be realized if the temperature is higher than or equal to the degree.

Therefore, the energizing section can be set to a maximum of 145 degrees.

An analog-type integrating circuit, a timer in a microcomputer, and the like are used to determine the start timing of the energized section, and the advance angle is adjusted by adjusting the time constant and the set time of the timer. It is also possible to make the current waveform of the winding similar to the no-load induced electromotive force waveform.

Since there is no induced electromotive force at the time of start-up, the above-described position detection method is not used, and a separate starting circuit is provided to forcibly increase the frequency and start up as a synchronous machine. It will be switched to operation. However, even with the above configuration, the present invention is significantly different from the prior art in that it does not require an increase in the number of wirings.

In this embodiment, as shown in FIG. 7, in the 140-degree conduction section, either the high potential side or the low potential side is kept off, but the control is particularly limited to such a control. Instead, the switching element on the high potential side and the switching element on the low potential side may be alternately turned on with a predetermined dead time in the carrier cycle of pulse width modulation. (Embodiment 3) FIG. 9 is an operation waveform diagram of a motor driving apparatus according to a third embodiment for describing the first, third, sixth and seventh aspects.

Also in the third embodiment, the motor driving device and the motor are realized with the same circuit diagram as FIG. 1 showing the first embodiment, and only the operation of the control circuit 58 is different.

In FIG. 9, pulse width modulation of each switching element is performed almost continuously to energize.

Therefore, the current waveform can be changed over almost the entire cycle, and the current waveform can be made closer to the no-load induced electromotive force waveform than in the second embodiment.

However, since there is no period during which both the high-potential side and the low-potential side switching elements are kept off, it is difficult to detect the position from the terminal voltage of the motor.

As an alternative, for example, it is possible to separately provide current detecting means for directly detecting the current of two phases out of the three phases, and to use a method of detecting the position based on the phase of the current. If the duty is changed so that the current waveform from the current detecting means becomes equal to the no-load induced electromotive force waveform, the configuration of the motor driving device becomes slightly complicated, but is substantially similar to the no-load induced electromotive force waveform. It is possible to realize a shaped current waveform, and also to improve the efficiency of the motor.

When such a current detecting means is provided, it may of course be provided for all three phases. However, in the case of a three-phase three-wire circuit, only two-phase currents among the three phases are detected. Then, the remaining one phase can also be obtained by calculation using the fact that the sum of the instantaneous values of the three-phase currents is always zero.

Further, even in a configuration in which the current of only one phase is detected and the current is electrically shifted by 120 degrees to obtain the current of the other two phases, sufficient performance may be exhibited in some cases.

In this embodiment, as shown in FIG. 9, all the switching elements always perform pulse width modulation.
In addition to such control, for example, for one of the three phases, a method of fixing the switching element on the high potential side or the low potential side to the ON state or the waveform of the duty change of the three-phase pulse width modulation may be used. A device that superimposes a 3n-order harmonic may be used. (Embodiment 4) FIG. 10 is a circuit diagram of an electric device according to a fourth embodiment for explaining the first, second, fourth to eleventh aspects.

Also in the fourth embodiment, the motor 42 and the motor driving device 50 have the same configuration as that of FIG. 1 showing the first embodiment, and the motor driving device 50 includes six nickel-metal hydride storage batteries in series. It receives the configured DC power supply 78, performs DC to AC conversion, and supplies the electric motor 42 with
The difference is that a current having a substantially similar shape to the no-load induced electromotive force waveform of the electric motor 42 is supplied to the windings 31, 32 and 33.

Also in the fourth embodiment, the control circuit 58 controls the switching elements 52 to 57 as shown in the first to third embodiments, so that the motor 42 can be driven with high efficiency. .

In particular, since the storage battery 78 is used,
It can be used for portable electric devices, electric vehicles, electric bicycles, cordless vacuum cleaners, and the like.

In the present embodiment, the voltage of the DC power supply 78 does not include a ripple component, as compared with the one using double voltage rectification as in the first embodiment.
The current waveform of 33 is more stable, and also has an effect that it can easily approach the no-load induced electromotive force waveform. (Embodiment 5) FIG.
FIG. 7 is a circuit diagram of an electric device 79 for explaining the embodiment.

In FIG. 11A, the electric motor 79 has a motor 42 and a motor driving device 80 having the same configuration as in the first embodiment.
And receives an AC power supply 60 of 100 volts and 60 hertz.

The motor driving device 80 includes six open / close circuits 8
1, 82, 83, 84, 85, 86, a power supply means 88 composed of a control circuit 87 for controlling ON / OFF of these switching circuits, a choke coil 89, and a capacitor 90.

FIG. 11A is a detailed circuit diagram of the opening / closing circuit 81, which includes a silicon bridge type rectifier 91 and a MOS.
The bidirectional on / off operation constituted by the FET 92 can be performed.

In this embodiment, the switching circuits 82 to 86 have the same configuration as that of the switching circuit 81. However, such a configuration is not necessarily required, and a bridge type such as silicon or selenium may be used. The use of the above circuit is merely an example, and the point is that the circuit can be turned on and off in both directions.

The operation in the above configuration is similar to the operation of the control circuit 87.
Is the position detection signal S from the electric motor 42 as in the first embodiment.
1, S2, and S3, but simultaneously detects the instantaneous value of the voltage VAC of the AC power supply 60, and according to the value, the switching circuit 8
1 to 86, and controls the on / off of the windings 31 of the electric motor 42;
The current waveforms 32 and 33 are controlled so as to be substantially similar to the no-load induced electromotive force of the electric motor 42.

The choke coil 89 and the capacitor 9
0 stabilizes the AC voltage input to the power supply means 88, and at the same time, removes the high frequency component of the current input from the AC power supply 60.

In the first embodiment, the AC from the AC power supply 60 is once rectified to DC, then converted to AC, and
In contrast, the motor drive device 80 according to the fifth embodiment supplies an AC current directly from the AC power supply 60 to the motor 42.
The third aspect of the present invention is realized by a configuration in which the power is supplied to

Therefore, particularly, the bidirectional switching circuits 81 to 81
If the configuration of 86 is simplified by modularization or the like, there is an effect that the configuration of the motor driving device 80 can be made very simple.

As described above, each of the motor drive devices or the motor devices of the first to fifth embodiments has a small torque even if the effective value of the current supplied to the windings 31, 32, 33 of the motor 42 is small. As a result, the copper loss of the electric motor 42 is reduced, and high-efficiency operation is possible.

In each of the embodiments, since the three-phase windings 31, 32, and 33 of the motor 42 are star-connected, when the three-phase windings are connected to the motor driving device 50, the three phases U, V, and W are used. And the sum of the instantaneous values of the currents is always zero.

However, the electric motor 42 of each embodiment is
Since the concentrated winding and the ratio of the number of poles to the number of slots are 2: 3, the sum of the instantaneous values of the no-load induced electromotive force of the three-phase windings 31, 32, and 33 is almost always zero. And the winding current waveform can be made sufficiently close to the no-load induced electromotive force waveform even under the limitation that the sum of the instantaneous values of the three-phase currents is always zero. .

The fact that the sum of the instantaneous values of the three-phase no-load induced electromotive force is always zero is explained as follows.

Assuming that the magnetic flux in the slots 74a to 74l shown in FIG. 2 is so small as to be negligible with respect to the magnetic flux passing through the teeth 75a to 75l, the portions of the two adjacent coils in the same slot will As a result, the sum of the no-load induced electromotive forces of the three-phase windings 31, 32, and 33 becomes 12 The voltage at both ends in a state where all the coils 73a to 73l are connected in series, the same electromotive force in the same slot is canceled in consideration of the polarity, and as a result, the instantaneous value of the no-load induced electromotive force is always zero.

Incidentally, when expressed in terms of frequency, both the no-load induced electromotive force and the current of the winding have almost zero 3n-order harmonics.

However, even in the case of distributed winding instead of concentrated winding, if the adjacent coils are arranged in the same slot by the same number of turns, the sum of the instantaneous values of the no-load induced electromotive force of the three-phase windings is also obtained. Can be set to zero, so if such a configuration is adopted, claim 9 will be very effective even if it is not a concentrated winding.

If the motor 42 is a distributed winding and a 3n-th harmonic component of the no-load induced electromotive force waveform of each of the three-phase windings is generated, in the three-phase star connection, the current waveform is inevitably changed by no-load induction. Although it is deviated from the similarity with the electromotive force, in many cases, it is possible to use claim 1 which can make the similarity close to the similarity due to harmonics of other orders in many cases. Can be realized.

It should be noted that, even if the phase is three, the middle point of the star connection, that is, the point indicated by N in FIG. When connected to the connection points 64 and 65, the current of the 3nth harmonic component can be supplied to the windings 31, 32 and 33, and the harmonic of any order can be supplied to the motor 42. This makes it possible to perform the control with an extremely high degree of freedom and to realize the configuration of claim 1 irrespective of the state of distortion of the no-load induced electromotive force waveform of the motor.

When the motor includes the motor 42 and the motor driving device 50, the no-load induced electromotive force waveform of the motor 42 used is fixed, and the motor driving device 50 supplies a similar current waveform. Can be realized and the copper loss can be sufficiently reduced. However, for example, for industrial use, the motor 42 is sold separately, and only the motor drive device 50 is traded alone. Also, the same effect can be obtained by supplying a current waveform substantially similar to the no-load induced electromotive force waveform of the electric motor 42 used in the set.

The same applies to the motor driving device 50 supplied as a service component of the motor having the motor 42 as a component.

The type of motor 42 to be connected is not one type,
If there are multiple types of motors, a setting that can supply multiple types of current waveforms is provided, and the user can select the configuration according to the type of motor actually used, and read / write is possible A non-load induced electromotive force waveform is read from the motor terminal voltage when the motor is rotated under no load by any method, and registered in the storage means, and in the subsequent operation, the stored waveform is read. Alternatively, control may be performed so as to obtain a current waveform.

Further, after the electric device or the electric motor drive device is traded, it can be realized by supplying software such as programs and data. In this case, the supply of the software can be realized by various media, A transmission method may be used, and a distribution channel is also free.

The electric motor 42 described in each embodiment has an SPM structure in which the rotor 71 is formed by bonding the permanent magnets 34 to 41 to the surface of the iron core 76 as shown in FIG. Even if the rotor 71 rotates, the windings 31, 3
The values of the self-inductance and the mutual inductance of the reference numerals 2 and 33 are substantially constant. Therefore, the generated torque is based only on Fleming's left-hand rule. In this case, in addition to the torque according to Fleming's left-hand rule, a torque called reluctance torque is superimposed on the generated torque.

The value of the reluctance torque is roughly classified into a first reluctance torque generated by a change in self-inductance and a second reluctance torque generated by a change in mutual inductance. The sum of the square of the instantaneous value of the current flowing in each case multiplied by the value obtained by differentiating the inductance by the mechanical angle, the second reluctance torque is the product of the currents of the two windings Are multiplied by the value obtained by differentiating the mutual inductance of the above with the mechanical angle.

For example, in addition to the power supply means 51 of each embodiment, a reluctance torque is added by adding a correction means for adding one or both of the first and second reluctance torques to the no-load induced electromotive force waveform. If the configuration is also such that the winding current waveform corresponding to the above is also supplied, it becomes possible to operate a high-efficiency motor using reluctance torque effectively.

In this case as well, the switching elements 52 to 57 and the like which are components of the power supply means 50 can be used as they are and can be realized by only slightly changing the on / off control pattern of each switching element. From
It does not add much cost.

[0156]

As described above, according to the present invention, copper loss can be reduced and efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an electric device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an electric motor of the electric device.

FIG. 3 is a connection diagram of windings of the electric motor.

FIG. 4 is an operation waveform diagram of each part of the electric motor driving device.

FIG. 5 is a waveform diagram showing a change in duty of the control circuit.

FIG. 6 (a) Same as above, current waveform diagram of motor winding (b) Same as above, no-load induced electromotive force waveform diagram of motor

FIG. 7 is an operation waveform diagram of each part of the electric motor drive device according to the second embodiment of the present invention.

FIG. 8 (a) Same as above, current waveform diagram of motor winding (a) Same as above, no-load induced electromotive force waveform diagram of motor

FIG. 9 is an operation waveform diagram of each part of the electric motor drive device according to the third embodiment of the present invention.

FIG. 10 is a circuit diagram of an electric device according to a fourth embodiment of the present invention.

FIG. 11 is a circuit diagram of an electric device according to a fifth embodiment of the present invention.

FIG. 12 is a circuit diagram of an electric device according to a conventional technique.

FIG. 13 is a sectional view of an electric motor of the electric device.

[Explanation of symbols]

31, 32, 33 Windings 34, 35, 36, 37, 38, 39, 40, 41 Permanent magnet 42 Motor 51, 88 Power supply means 50, 80 Motor drive 78 DC power 60 AC power 74a, 74b, 74c, 74d, 74e, 74f, 7
4g, 74h, 74i, 74j, 74k, 74l Slot

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kazuhiko Asada 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Tomoya Toto 1006 Okadoma Kadoma, Kadoma City Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Yasudo Kobayashi 1006 Kazuma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. (72) Inventor Hideki Omori 1006 Odaka Kazuma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. (72) Haruo Terai Inventor 1006 Odakadoma, Kadoma, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd. (72) Inventor Masanori Ogawa 1006, Odakadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Tomoaki Iriji Takaida, Higashiosaka, Osaka Matsushita Refrigeration Machine Co., Ltd. 4-5-2, Hondori (72) Inventor Koji Hamaoka 4-chome Takaida Hondori, Higashi Osaka 2-5, Matsushita Refrigerating Machinery Co., Ltd. (72) Inventor Kanji Izaki 6-2-61, Imafuku Nishi, Joto-ku, Osaka City, Osaka Prefecture Matsushita Seiko Co., Ltd. (72) Inventor Masato Ogata Ito, Joto-ku, Osaka City, Osaka 6-2-61 Fukunishi Matsushita Seiko Co., Ltd. F-term (reference) 5H560 AA02 BB04 BB07 BB12 DA03 DA19 EB01 EC02 RR04 SS07 TT01 UA02 UA05 UA06 UA08 XA12 5H576 AA08 AA10 AA11 AA12 BB02 CC05 DD02 DD07EE04 LL41

Claims (11)

[Claims] 1. An electric motor drive device connected to an electric motor having a winding and a permanent magnet, and having a power supply means for supplying a current having a waveform substantially similar to a no-load induced electromotive force waveform of the electric motor to the electric motor. 2. The electric motor driving device according to claim 1, wherein the electric power supply means supplies the electric current to the electric motor after converting the direct current power into the alternating current. 3. The electric motor driving device according to claim 1, wherein the electric power supply means receives an alternating-current power supply having a constant frequency, and supplies the electric current after conversion from alternating current to alternating current to the electric motor. 4. The motor drive device according to claim 1, wherein the electric angle of the energized section is set to approximately 120 degrees. 5. The motor drive device according to claim 1, wherein an electric angle of the energized section is set to 120 degrees to 145 degrees. 6. The method according to claim 1, wherein the absolute value of the difference between the fifth harmonic rate of the winding current waveform and the fifth harmonic rate of the no-load induced electromotive force is 10% or less. Motor drive. 7. The motor drive device according to claim 1, wherein an absolute value of a difference between a waveform ratio of the winding current waveform and a waveform ratio of the no-load induced electromotive force is 0.1 or less. 8. An electric motor comprising: an electric motor having a winding and a permanent magnet; and the electric motor drive device according to claim 1. Description: 9. A winding having a three-phase star connection.
An electric device as described. 10. The electric device according to claim 8, wherein the winding is formed by concentrated winding. 11. The motor according to claim 1, wherein the ratio between the number of poles and the number of slots is two.
11. The electric device according to claim 10, wherein the ratio is three.