JP2002078370A - Inverter apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize low vibration and low noise for a motor having permanent magnets. SOLUTION: This inverter apparatus comprises a motor, in which permanent magnets 150 to 158 of p-poles coils 102, 103, 104 of k-phase are provided through the centralized winding to an iron core 172, having grooves 174a to 1 of the number obtained by dividing a value (p×k) by 2. An inverter circuit 101 supplies a current, to provide the result that a sum of the products between the instantaneous value and current value of no-load inductive electromotive force of coils 102, 103, 104 of each phase. Thereby, the variations in generated torque can be controlled, and moreover low vibration and low noise of motor 100 can also be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device, such as a washing machine or a vacuum cleaner, which performs a rotary motion and is used in homes, factories, offices, stores, transportation and the like. It is.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No.
596, and a single-phase inverter equal to the number of phases connected to the motor 1 as shown in the block diagram of FIG. 2, 3, 4, and having a DC power supply 5;
An inverter circuit 6 is provided, and windings 7 of each phase of the electric motor 1 are provided.
8 and 9, the instantaneous value of the current is a value proportional to the induced electromotive force generated in the winding of that phase, and inversely proportional to the sum of the squared instantaneous values of the induced electromotive forces of all phases. As described above, by controlling the rotor 10, the motive power in which the ripple of the generated torque is reduced to zero is supplied to the load 11 to the rotor 10 of the electric motor 1,
Vibration was reduced.

[0003]

In the above prior art, the windings 7, 8 of each phase of the general motor 1 are used.
9, the harmonics included in the induced electromotive force waveform are the same as the number of phases and an integer multiple thereof, that is, for example, in a three-phase device, any one of the third, sixth, ninth, and twelfth orders is used. In order to supply a current waveform capable of reducing the torque ripple to zero because of the harmonics of the single-phase inverter 2 having four switching elements as shown in FIG. It is necessary to provide a configuration in which three, four, and the same number of phases are provided. For example, in the case of a three-phase configuration, as many as twelve switching elements are required.

[0004] Therefore, there is a first problem that the number of switching elements required for realizing the inverter device is very large, and the device is complicated and the cost is high.

In particular, when the distortion of the no-load induced electromotive force is large, if the torque ripple is made zero by the conventional configuration, the distortion of the current waveform becomes large, and the vibration caused by the torque ripple becomes large.・ Noise is eliminated, but the spectrum of vibration and noise generated by magnetostriction and current force between conductors from windings and iron cores is generated over a wide range, resulting in lower vibration and lowering of equipment. There was a second problem that noise could not be sufficiently reduced.

The present invention solves the first problem and reduces the number of switching elements by limiting the order of harmonics of the no-load induced electromotive force generated in the winding of the motor. It is an object of the present invention to realize an inverter device capable of suppressing the reduction of torque ripple in the configuration, realizing low vibration and low noise while minimizing copper loss of an electric motor while being small in size and low in cost.

[0007] Further, the present invention solves the second problem, and reduces the combined vibration of the vibration caused by the torque ripple and the vibration generated by the current distortion as a whole, thereby realizing the lowest vibration and the lowest noise. Data device can be provided.

[0008]

In order to solve the above-mentioned problems, the present invention has a k-phase winding and a p-pole permanent magnet, and the winding divides a value obtained by multiplying p by k by two. A motor having k input terminals and an inverter circuit for supplying current to the windings, the inverter circuit being provided with concentrated windings on an iron core having an integral number of grooves. An inverter device is configured to supply a current in which the sum of the product of the instantaneous value of the no-load induced electromotive force and the current value of the winding is substantially constant to the winding of each phase.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention described in claim 1 is particularly advantageous when k
Phase winding and a p-pole permanent magnet, and the winding is provided in a concentrated winding on an iron core having an integer number of grooves obtained by dividing p multiplied by k by two. And an inverter circuit for supplying a current to the winding, wherein the inverter circuit calculates the sum of the product of the instantaneous value and the current value of the no-load induced electromotive force of the winding of each phase. By supplying a substantially constant current to the windings of each phase, the k-th harmonic component contained in the no-load induced electromotive force and its integral multiple components are suppressed to extremely small values, and the input terminal of the motor The present invention is to provide an inverter device that realizes low vibration and low noise while suppressing the copper loss of the windings of the electric motor and suppressing the torque ripple while having the minimum number of k.

According to a second aspect of the present invention, there is provided an electric motor having a k-phase winding, and an inverter circuit for supplying a current having a distortion to the winding.
Supplying a current waveform in which the ripple amount of the sum of the products of the no-load induced electromotive force of each phase and the instantaneous value of the current is approximately half the ripple generated when a sine wave current is supplied to the motor. Accordingly, the present invention provides an inverter device in which the combined vibration of the vibration caused by the torque ripple and the vibration generated by the current distortion is comprehensively reduced to realize the lowest vibration and the lowest noise.

According to a third aspect of the present invention, there is provided an electric motor having a k-phase winding, and an inverter circuit for supplying a current having a distortion to the winding.
The ripple amount of the sum of the product of the no-load induced electromotive force of each phase and the instantaneous value of the current is set to substantially the same value as the amplitude of the cogging power of the electric motor, so that torque fluctuation due to cogging is suppressed, and high efficiency is achieved. An operable inverter device is provided.

[0012] The invention described in claim 4 is particularly advantageous in claim 1 to claim 1.
3. The inverter circuit according to claim 3, comprising a DC power supply and switching elements twice as many as k, wherein the switching element is provided between a plus terminal of the DC power supply and an input terminal of the motor. And by being connected between the negative terminal of the DC power supply and the input terminal of the motor,
An inverter device that can realize low vibration and low noise while suppressing the number of switching elements and realizing compactness and low cost.
To provide.

[0013] The invention described in claim 5 is particularly advantageous in claim 1 to claim 1.
By setting k = 3 in the inverter device according to any one of the above items 4, the number of switching elements is as small as 6 stones, and the configuration of the winding of the motor is simple. An inverter device capable of realizing low vibration and low noise is provided.

[0014]

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

FIG. 1 is a circuit diagram of an inverter device according to a first embodiment.

The inverter device shown in FIG.
The motor 100 has three phases and is equal to the U-phase winding 102, the V-phase winding 103, the W-phase winding 104, and the number of phases 3.
It has three input terminals 105, 106, 107.

Further, in the electric motor 100, the three-phase windings 102 to 104 are star-connected (Y-connected), and furthermore, a position detecting means 111 constituted by Hall ICs 108, 109 and 110 is provided. The position of the rotor 112 in the rotation direction is detected.

The inverter circuit 101 includes a DC power supply 120
And six switching elements 121 twice as many as three phases
To 126, and a control circuit 127 for controlling on / off of the switching elements 121 to 126. The switching elements 121, 122, and 123 include a plus terminal 130 of the DC power supply 120 and an input terminal 105, 106 of the electric motor 100, respectively. , 107, and the switching elements 124, 125, 126 are connected between the minus terminal 131 of the DC power supply 120 and the input terminals 105, 106, 107 of the electric motor 100, respectively. Thus, a current is supplied to the windings 102 to 104.

In this embodiment, the switching elements 121 to 121
Reference numeral 126 denotes a configuration in which an IGBT and a rectifying element are connected in parallel using a silicon semiconductor.
It is not an absolute condition. For example, a MOSFET, a bipolar type, a DGMOS, a GTO, or the like may be used.
In addition to silicon, germanium, silicon carbide (SiC), or the like may be used.

In the first embodiment, the DC power supply 120 has an effective value of 100 volts and a constant frequency (60 Hz or the like).
A full-wave rectification is performed by an AC power supply 133, a choke coil 134, rectifiers 135 to 138, and an electrolytic capacitor 139 using a commercial power supply, and a 140 V DC voltage is output when there is no load. .

However, full-wave rectification as a configuration for converting from AC to DC is merely an example, and double-voltage (double-voltage) rectification or half-wave rectification may be used.

The rectifying elements 135 to 138 can be configured as rectifying elements using a material other than silicon, for example, germanium, silicon carbide (SiC), selenium, or the like.

FIG. 2 is a detailed configuration diagram of the electric motor 100 according to the first embodiment.

The electric motor 100 comprises a stator 170 and a rotor 112. The stator 170 has a core 172 formed by stacking 40 silicon steel sheets each having a thickness of 0.5 mm, and coils 173a, 173b, 173c. , 173d, 173
e, 173f, 173g, 173h, 173i, 173
j, 173k and 173l.

The shape of the iron core 172 has 12 grooves 174.
a, 174b, 174c, 174d, 174e, 174
f, 174g, 174h, 174i, 174j, 174
k, 174l and 12 teeth 175a, 175
b, 175c, 175d, 175e, 175f, 175
g, 175h, 175i, 175j, 175k, 175
and each coil is wound around a portion of each tooth.

On the other hand, the rotor 112 is made of forged iron and functions as a magnetic path. Eight permanent magnets 150, 151, 152, 153, 154,
155, 156, 157 are glued, and around the shaft 160,
While rotating, apply torque to various mechanical loads (not shown)
To provide power.

The mechanical load includes a stirring blade, a dewatering tub, a ventilation fan and the like when used as a washing machine.
Examples include a fan, an air conditioner when used as a vacuum cleaner, and a compressor when used for a refrigerator, but other applications are also possible.

Here, the permanent magnets 150, 152, 15
4 and 156, the N pole is formed on the outside, that is, on the surface facing the stator 170, and the permanent magnets 151 and
Regarding 153, 155, and 157, since the S pole is formed on the outside, that is, on the surface facing the stator 170, the rotor 112 having eight poles is realized.

Therefore, in this embodiment, the number of phases k = 3
Where the number of poles p = 8 and the number of grooves is 12, which is k and p
Is divided by 2 and the number of input terminals is 3.
It is.

FIG. 3 shows a winding 1 of the electric motor 100 according to the first embodiment.
FIG. 3 is a connection diagram showing a configuration of 02, 103, and 104, and each winding is configured by a series circuit of four coils.

That is, the U-phase winding 102 is
3a, 173d, 173g, 173j, V-phase winding 10
3 is a coil 173b, 173e, 173h, 173k,
The W-phase winding 104 has coils 173c, 173f, 173
i, 173l in series.

Here, a black circle attached to one side of each coil indicates the polarity. When a current flows from the side with the black circle, each coil has an inner side, that is, a rotation. On the side facing the child 112, it is wound so that an N pole is generated.

Therefore, for example, the U-phase input terminal 105
When a current flows from the coil 102, the magnetomotive force generated by the four coils constituting the winding 102 becomes the same pole (N pole) at the position shifted by 90 degrees in FIG. 2 and operates as an eight pole machine.

The winding method in which one pole is formed by one coil is generally called concentrated winding. In this embodiment, the winding of each coil has an electrical angle of 120 degrees and the concentrated winding has By doing so, the copper wire length of the so-called coil end can be shortened, the electrical 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 are small. It is possible to reduce costs, lead to effective use of resources, and contribute to protection of the global environment.

As an advantage in the case of concentrated winding as in the present embodiment, the iron core 172, which is called a split core, is manufactured by dividing it into 12 pieces, and the coils 173a to 173l are wound. It is also possible to adopt a manufacturing method of forming one stator 170 by welding or the like after the welding, so that the slots 174a to 174 can be adopted.
The net cross-sectional area of the copper wire, that is, the so-called copper space factor with respect to the area of l, can be remarkably improved, and thus has the effect of contributing to performance improvement such as reduction of copper loss.

Even when the number of phases k is fixed to 3, the number of poles p and the number of grooves are not limited to the 8 poles and 12 grooves shown in the present embodiment, but may be 6 poles, 8 grooves or 4 poles. It may have six grooves or the like, and may have an advantageous configuration in the case of a device in which vibration does not matter even with two poles and three grooves.

The terminal N shown in FIG. 3 is called a neutral point or the like, and is a point connecting one terminal of the three-phase windings 102, 103 and 104, and serves as a reference point of the phase voltage. However, the motor 100 and the inverter circuit 101 are not connected to the inverter circuit 101, and k is equal to the number k of phases.
In the present embodiment, that is, in this embodiment, the connection is made by three wires.

FIG. 4 shows a state where no load is applied, that is, the input terminal 1
With the electric motors 100, 05, 106 and 107 open,
The other motor is connected to the shaft 160 of 150 r / min.
The harmonic components of each order included in the phase voltage of the no-load induced electromotive force, which is the voltage of the U-phase input terminal 105 from the neutral point N in the state of rotation at the speed of It is shown.

The waveform of the no-load induced electromotive force varies depending on the specifications of the windings 102, 103, and 104 of the motor 100, the magnetization distribution of the permanent magnets 150 to 157, and the like. And contains harmonic components.

As shown in FIG. 4, in addition to the fundamental wave (order is 1), fifth and seventh harmonic components appear, but the other harmonic components are almost zero. Since the three phases are equal, the V phase and the W phase have exactly the same harmonic components as the U phase although the phases are shifted by 120 degrees.

Such harmonic components are generated by the motor 100
Although it is possible to reduce by the design of the above, in that case, the utilization efficiency of the magnetic flux of the used permanent magnet tends to decrease, and in order to make the most of the permanent magnet work effectively and obtain a large torque As in this example,
A waveform of a no-load induced electromotive force (phase voltage) containing a harmonic component effectively acts.

In the present embodiment, the centrally wound and provided
Since the width of each of the windings 102, 103, and 104 is a value obtained by dividing 2π in electrical angle by 3 which is the number of phases, of the harmonic components included in the electromotive force, 3 Components corresponding to integer multiples are canceled out to be zero, and even-order components are zero due to symmetry in the rotation direction of the motor 100, and higher-order components of order 11 or higher are almost negligible. As a result, the fifth-order and seventh-order components are present as shown in FIG.

FIG. 5 shows an operation waveform diagram of the control circuit 127 of the first embodiment. FIG. 5A shows a waveform of the gate signal UP of the switching element 121, and FIG.
Is the waveform of the gate signal VP of the switching element 122,
FIG. 4C shows the gate signal W of the switching element 123.
4D is a waveform of the gate signal UN of the switching element 124, FIG. 4E is a waveform of the gate signal VN of the switching element 125, and FIG. 7 is a waveform of a signal WN.

The gate signals of any of the switching elements are almost continuously subjected to pulse width modulation with a carrier frequency of 15.625 kHz, and are energized.

FIG. 6 shows an operation waveform diagram of the inverter device of the first embodiment under the condition that the torque is 4.75 Nm and the machine speed is 150 r / min, with the horizontal axis representing the electrical angle. is there.

The electric angle is obtained by multiplying the time t [s] by the electric angular velocity ω (= 3600 [degrees / s]).

FIG. 6A shows the waveforms of the no-load induced electromotive force (phase voltage) of each of the three phases (U-phase, V-phase, and W-phase).
(A) is the current supplied to the windings 102, 103 and 104 of the motor 100, and (c) is the product of (a) the no-load induced electromotive force of each phase and (a) the instantaneous value of the current waveform. The figure shows the respective mechanical output powers and the total mechanical output power of the three phases (power supplied from the shaft 160 to the load).

In the present embodiment, as shown in FIG. 5, by continuously pulse width modulating the switching elements 121 to 126, it is possible to change the current waveform of each phase over almost the entire period. Therefore, the inverter circuit 101 includes the windings 102, 103, 104 of each phase.
It is possible to supply the windings 102, 103, 104 with a current in which the sum of the product of the instantaneous value of the no-load induced electromotive force and the current value is substantially constant.

That is, as is well known, the permanent magnets 150 to 157 and the winding 1 like the electric motor 100 of the present embodiment are used.
In the electric motors having the numbers 02 to 104, the instantaneous value of the product of the torque and the speed (mechanical output power) generated by the so-called Fleming's left-hand rule is equal to the product of the no-load induced electromotive force and the current value. As shown, when a current in which the sum of the product of the instantaneous value of the no-load induced electromotive force and the current value is substantially constant is supplied to the motor 100, the mechanical output power is constant, but the output power is Because it is the product of the rotation speed and the torque, that is, a constant torque can be obtained, the torque ripple (torque pulsation) can be made almost zero, and the noise and vibration of the device generated due to the torque ripple can be reduced. It can be kept low.

However, the condition of the conduction ratio of the switching elements 121 to 126 at which the total of the three-phase power outputs is constant varies depending on the torque and speed as the operating conditions of the electric motor 100. In the embodiment, the condition of the conduction ratio of the switching elements 121 to 126 in the two-dimensional condition setting of the torque and the speed is stored in a ROM element in the control circuit 127 in a form matched with the characteristics of the electric motor 100 in advance. Therefore, even when there are fluctuations in various load conditions, a state in which the power output power (power power) is almost constant as shown in FIG. Can be improved.

There are various types of waveforms of the current i that keep the total value of the power output power of the three phases constant at all times. The power distribution is set to a value proportional to the square of the no-load induced electromotive force of each winding, so that the condition that the torque ripple is zero is realized. It is supposed to be.

In the power distribution described above, the value of the current supplied to each phase winding at each moment is a value obtained by dividing the no-load induced electromotive force of that phase by a predetermined value common to all phases, and is proportional to the proportional relationship. Become.

Here, as for the harmonic components of the current waveform of each phase shown in FIG. 6A, the 3n-th harmonic is included in the no-load induced electromotive force (phase voltage) shown in FIG. Otherwise, in a waveform in which the current waveform does not include the 3n-th harmonic component, a current waveform that minimizes copper loss under the condition that the above-described torque ripple is zero is realized.

On the other hand, in the connection of the three-phase three-wires as shown in FIG. 1, the condition is that the instantaneous value of the three-wire current is always zero. There is also a condition that the presence of the 3n-order component is not allowed.

Therefore, by using the electric motor 100 constituted by concentrated winding of eight poles and twelve grooves shown in the present embodiment, the generated current waveform, which is a three-phase three-wire, has a harmonic component which is allowed to exist. Within this range, a current waveform with the smallest copper loss can be realized, and an inverter device with high efficiency and zero torque ripple can be realized.

The ratio of the harmonic component to the fundamental wave is 8.0% for the 5th order and 2.8% for the 7th order in the no-load induced electromotive force (phase voltage). In the current of the present embodiment, the fifth-order current is 2.8%, and the seventh-order current is 8.8%.
It is assumed that 0% is contained, and it is just reversed.

As described above, in the first embodiment, in a three-phase configuration where k = 3, the number of switching elements 121 to 126 used in the inverter circuit 101 can be reduced to an extremely small number of six, thereby simplifying the operation. The configuration is low cost, and the motor 100 and the inverter circuit 101
The number of wires connecting them is three, making it an extremely simple device, but with almost zero torque ripple, reducing vibration and noise, and minimizing copper loss. A one-piece device is realized.

(Embodiment 2) FIG. 7 is an operation waveform diagram of the inverter device in Embodiment 2.

Also in the second embodiment, the three-phase winding 102,
The block configuration of the electric motor 100 having 103 and 104 and the inverter circuit 101 is equivalent to that of the first embodiment, and the inverter circuit 101 supplies a current having a distortion to the windings 102, 103 and 104. is there.

The second embodiment is different from the first embodiment only in the operation of the control circuit 127. The pattern of the duty ratio of the switching elements 121 to 126 is different from that of the first embodiment. By doing so, the inverter circuit 101 sets the ripple amount of the sum of the product of the no-load induced electromotive force of each phase and the instantaneous value of the current with respect to the ripple generated when a sine wave current is supplied to the motor 100. , Which supply a current waveform that is almost half.

FIG. 7A is a waveform of a U-phase no-load induced electromotive force (phase voltage) e, FIG. 7A is a waveform of a U-phase current i,
(C) shows the waveform of the power output power Pout of the U phase and the total of the three phases.

In FIGS. 7A to 7C, the V phase and W
The phase waveforms are not shown because the drawing is complicated,
The phase has a waveform shifted by 120 electrical degrees from the U phase, and the W phase has a waveform shifted by 240 electrical degrees from the U phase.

In FIGS. 7A and 7C, the solid line indicates the second embodiment.
5 shows an operation waveform of the inverter device, and shows a state in which a sine-wave current is supplied to the electric motor 100 for comparison.

As shown in FIG. 7C, in the case of a sinusoidal current waveform indicated by a broken line, the power output power obtained by summing the three phases has an electrical angle of 60 degrees as a period, that is, a six-fold frequency component. , Ripples (pulsations) are superimposed.

Even if the power Pout has a ripple,
The torque ripple is absorbed by the rotor 112 of the electric motor 100 and the moment of inertia of the load connected to the rotor 112. Therefore, the problem of speed fluctuation (rotation unevenness) does not occur except for special low-speed conditions. It can cause noise.

In the second embodiment shown by the solid line, by supplying a current waveform having a slight distortion as shown in FIG. 7A, the power output of the three-phase total shown in FIG. The magnitude of the power ripple is set to approximately 1 in the case of the broken line.
/ 2.

FIG. 8 shows the torque ripple rate, the harmonic current rate, and the noise value of the device under various current waveform conditions A, B, and C.

In FIG. 8, A shows the condition when a sine wave current is supplied to the motor 100, B shows the condition in the second embodiment, and C shows the condition in the first embodiment.

The torque ripple ratio is a value obtained by subtracting the minimum value from the maximum value of the total power output power of the three phases described above by the average value. The harmonic current ratio is the fifth and seventh harmonic current components. Is divided by the fundamental component, and the noise value is the average of the measured noise values at a predetermined distance from the front and side surfaces of the machine when applied to a fully automatic washing machine. Things.

Since the current waveform of A is a sine wave, the harmonic current ratio is zero for the fifth and seventh orders, but the torque ripple ratio is 10.4%.

Further, under the condition C, since the total power output power of the three phases is always constant, the torque ripple rate is zero, but the harmonic current rate is considerably high, and especially, the seventh order is 8.0%. Has become.

As for B, since the current waveform is slightly distorted, the harmonic current ratio is 5th 4.0%, 7th 6.
6%, which is smaller than C, and the torque ripple is half of A, 5.2%.

The causes of vibration and noise include various factors. The torque ripple and harmonic current are
This is a major factor.
Vibration and noise generated by the magnetostriction of 72 exist.

As shown in FIG. 8, the results of the noise measurement by the inventors are as follows: A is 35.0 dB, and B is 33.3 dB.
dB and C were 34.1 dB, and B was the lowest value.

This is considered to have been obtained because the fifth-order and seventh-order harmonic current ratios and the torque ripple ratio were low values when viewed comprehensively. Is approximately half of the condition A (current is a sine wave), the noise dB value is the lowest.

However, in the experiments conducted by the inventors, noise caused by the difference between the structure of the electric motor 100 depending on whether it is an iron machine or a copper machine, the state of varnish impregnation of the enamel wire constituting the winding, or the presence or absence of the resin mold, etc. , The torque ripple rate was slightly changed, but in any case, the torque ripple rate was 35% to 65% with respect to the condition A.
Within the range, the noise was lowest.

As described above, in the second embodiment, the inverter circuit 101 outputs the ripple amount of the sum of the product of the no-load induced electromotive force of each phase and the instantaneous value of the current to the motor 100 so that the sinusoidal current By supplying a current waveform that is almost half of the ripple generated when the power supply is supplied, an inverter device capable of reducing vibration and noise is realized.

(Embodiment 3) FIG. 9 is an operation waveform diagram of an inverter device in Embodiment 3.

Also in the third embodiment, the three-phase winding 102,
The block configuration of the electric motor 100 having 103 and 104 and the inverter circuit 101 is equivalent to that of the first embodiment, and the inverter circuit 101 supplies a current having a distortion to the windings 102, 103 and 104. is there.

The third embodiment is different from the first embodiment only in the operation of the control circuit 127. The pattern of the duty ratio of the switching elements 121 to 126 is different from that of the first embodiment. By doing so, the inverter circuit 101 makes the ripple amount of the sum of the product of the no-load induced electromotive force of each phase and the instantaneous value of the current substantially equal to the amplitude of the cogging power of the electric motor 100.

FIG. 9A shows the waveform of the no-load induced electromotive force (phase voltage) e of each phase, FIG. 9A shows the waveform of the current i of each phase, and FIG. 9D shows the torque Tc output by the cogging and the corrected torque-Tc waveform having the opposite sign in the two-dot chain line, and FIG.
Although the waveform of the power output power Pout of the phase total is shown, P1 shown by the solid line is a product of the instantaneous value of (A) and (A) calculated by summing the three phases, and Further, the cogging power (power of the power), which is obtained by multiplying the cogging torque Tc [Nm] shown in (c) by the mechanical angular velocity [rad / s] of the electric motor 100, was obtained by adding up It shows the total output power P2 from the shaft 160 of the electric motor 100.

Generally, in an electric motor using a permanent magnet, the opening (slot opening) of the groove in the iron core depends on the angle of the rotor, regardless of the presence or absence of an electric current, due to the attractive force of the iron core and the permanent magnet. Because of the condition of high resistance, there is a torque called cogging. In this embodiment, as shown in FIG.
A cogging torque having a period of degrees, that is, a six-fold frequency component is present.

In this embodiment, the current waveform is shown in FIG.
As shown in (a), the distortion is applied to cancel the Tc in FIG. 9 (c), and the power shown in P1 of FIG. Is output, and as a result of adding cogging thereto, a constant output shown in P2, that is, the axis 16
From 0, the power supplied to the load is obtained, the fluctuation of the torque is almost zero, and an inverter device with low vibration and noise is realized.

By the way, the phase of the ripple that P1 has is
This is different from FIG. 7C described in the second embodiment, and the phase of the harmonic component included in the current is different from that of the second embodiment.
Is different from the one described above.

Here, the harmonic component of the current shown in FIG.
The 7th order becomes 8.2%, which is also zero for the 3nth harmonic.

Also in the third embodiment, the harmonic component of the no-load induced electromotive force (phase voltage) of the motor 100 is substantially zero for the 3n-th order.
Under the condition that is completely constant, the copper loss is the lowest,
In order to realize the current waveform, the 3nth harmonic component of the current is not necessary at all, and therefore, as described above, the sum of the instantaneous values of the current, which is the condition of the three-phase three-wire, is zero.
Even under the limitation, it is possible to operate at a constant P2 with minimum copper loss without any trouble.

(Embodiment 4) FIG. 10 shows a configuration diagram of an electric motor in Embodiment 4.

In Examples 1 to 3, the number of phases k is 3, 3
However, in the fourth embodiment, a configuration other than three phases is shown.

In FIG. 10, the motor, which is actually a circle, is described as a straight line, that is, as a linear motor for the sake of explanation.

Further, a partial configuration corresponding to two poles of the permanent magnet (one for each of the N pole and the S pole), that is, an electrical angle of 360 degrees is shown.

In FIG. 10, the permanent magnets 191 and 192
Is provided in a state of being bonded to the iron core 193,
The permanent magnet 191 has an N pole on the lower surface of FIG. 10 and the permanent magnet 192 has an S pole, and each has an electrical angle of 180 degrees.

In the concentrated winding, the k-phase winding 196 provided,
197, 198 and k connected from one terminal of each winding.
Although input terminals 200, 201 and 202 are provided, k may be an arbitrary integer, and FIG. 10 shows only three of them.

The other terminals of the windings 196 to 198 are connected in common and set to the neutral point N. However, as described in the other embodiments, the connection to the inverter circuit is established. Therefore, the motor and the inverter circuit are connected by k wires.

In this embodiment, the number of phases is k and the electrical angle is 36.
This means a state in which 0 degrees is equally divided into k, and thus k grooves 210 provided in the iron core 195,
Both 211 and 212 are provided equally at an electrical angle of 360 / k.

Although not shown, the inverter circuit has one switching element and a negative terminal between each of the k input terminals 200 to 202 and the positive terminal of the DC power supply. It is clear that the total number of switching elements is twice as large as k since one switching element is also connected between.

FIG. 10 shows two poles, that is, p = 2
, Only k portions are shown with respect to the electrical angle of 360 degrees, but p is a multiple of 2,
If it is 6, 8 ..., the number of grooves will be 2
For example, as in the case of eight poles shown in the first embodiment, a plurality of coils having the same electrical angle (phase) are connected in series or in parallel to form a winding. Can also be configured.

In the above configuration, the phase voltage of the no-load induced electromotive force is determined based on the N terminals and the input terminals 200, 20
The voltage of each phase of the first and second phases 202 is measured in an open state under a forced motion condition from an external drive source.
The following description is based on the N terminal.

Here, all the magnetic fluxes emitted from the permanent magnets 191 and 192 pass through the teeth portion, that is, one of the windings 196 to 198, and
The magnetic flux in 0, 211, 212 becomes zero.

In this case, the voltage generated between both ends of the winding 196 becomes the difference between the induced electromotive forces generated in the front and rear conductors due to the movement of the permanent magnets 191 and 192, e1a-e1b. This is a value generated by a phase difference of 360 degrees / k.

On the other hand, regarding the harmonic component of the induced electromotive force, in the Nth order, the phase difference between e1a and e1b is 3
60 degrees / k is multiplied by N, so that N is k
I.e., N = n * k (where n = 0,
1, 2, 3, 4...), The phase difference becomes an integral multiple of 360 degrees, becomes in-phase, and e1a−
Since e1b becomes zero, as a result, the k * n-order harmonic components of the no-load induced electromotive force (phase voltage) become zero.

The same applies to other phases.

Therefore, in the fourth embodiment, the k * n-order harmonic is not included in the phase voltage of the no-load induced electromotive force of each phase.

Therefore, in the fourth embodiment, when the torque ripple as described in the first embodiment is set to zero,
As described in the second embodiment, when the torque ripple is suppressed to a half of the case where the current is a sine wave current, and in the third embodiment,
Which action to cancel cogging
In order to distribute the instantaneous power so that the copper loss is minimized even in the case of performing the operation with the phase configuration, the instantaneous value of the current supplied to each phase is determined by the no-load induced electromotive force ( Phase voltage), it is necessary that the current waveform satisfying the value does not need the k * n-order harmonics.

That is, in a configuration in which the k-phase motor and the inverter circuit are connected by k wires, the limitation that the total instantaneous value of the current of each phase is always zero is generated. Thus, even under the restriction that the k * n-th harmonic current component cannot be present, the above-described copper loss can be sufficiently minimized, and a highly efficient device can be operated with a current waveform. The effect can be raised.

This means that the sum of the instantaneous values of the no-load induced electromotive force (phase voltage) is almost always zero in the motor having the configuration of the present embodiment, and is therefore proportional to the instantaneous induced electromotive force. In the case where each phase current is supplied to each winding, the winding current of each phase at that moment has a value proportional to the no-load induced electromotive force of each phase. Is always almost zero current.

The no-load induced electromotive force of each phase (phase voltage)
That the sum of the instantaneous values becomes almost zero means that the induced electromotive force of the adjacent conductor in the same groove in FIG.
When the magnetic flux density of the groove is very low and the value is negligible, the absolute value is equal, and the total electromotive force is almost zero when e.g. Is what you can do.

Here, when the torque ripple is set to zero,
In any case of suppressing torque ripple to half of the case of sinusoidal current or canceling cogging, the output power (power) is instantaneously changed and distributed to each phase in any operation. As a result, the current of each phase is changed by multiplying each of the currents by a constant ratio.

Therefore, no matter what value is multiplied with respect to each of the k-phase currents, the above-mentioned state in which the instantaneous value of the k-phase current is always zero is maintained. In any case where the above-described torque ripple is set to zero, the torque ripple is suppressed to half of the case where the sinusoidal current is used, and cogging is canceled, the electric resistance R of the windings 196, 197, 198 is used.
To the square of I, R
The state that minimizes the copper loss of the value multiplied by is k lines,
The motor can be connected to the inverter circuit, and the number of switching elements can be twice as many as k.

That is, it is possible to obtain an effect of realizing with an extremely simple configuration. In addition, the concentrated winding configuration allows the coil end to be particularly short, and the winding 19
6, 197, 198, the resistance R is kept small, the copper loss is further suppressed, high efficiency is obtained, and the synergistic effect can be improved.

[0110]

As described above, according to the present invention, the invention according to claim 1 has a k-phase winding and a p-pole permanent magnet, and the winding multiplies p by k. A motor having k input terminals and an inverter circuit for supplying a current to the windings, the motor being provided in a concentrated manner on an iron core having an integral number of grooves obtained by dividing the value obtained by 2 into two. The circuit supplies a current in which the sum of the product of the instantaneous value and the current value of the no-load induced electromotive force of the winding of each phase is substantially constant to the winding of each phase, thereby reducing the no-load induced electromotive force. The k-order component of harmonics and its integral multiple components are suppressed to extremely small values, and while the number of input terminals of the motor is the minimum number of k, copper loss in the winding of the motor is suppressed and torque ripple is suppressed. And an inverter device that realizes low vibration and low noise.

The invention according to claim 2 comprises an electric motor having a k-phase winding, and an inverter circuit for supplying a current having a distortion to the winding, wherein the inverter circuit comprises:
Supplying a current waveform in which the ripple amount of the sum of the products of the no-load induced electromotive force of each phase and the instantaneous value of the current is approximately half the ripple generated when a sine wave current is supplied to the motor. Accordingly, the present invention provides an inverter device in which the combined vibration of the vibration caused by the torque ripple and the vibration generated by the current distortion is comprehensively reduced to realize the lowest vibration and the lowest noise.

According to a third aspect of the present invention, there is provided a motor having a k-phase winding, and an inverter circuit for supplying a current having a distortion to the winding.
The ripple amount of the sum of the product of the no-load induced electromotive force of each phase and the instantaneous value of the current is set to substantially the same value as the amplitude of the cogging power of the electric motor, so that torque fluctuation due to cogging is suppressed, and high efficiency is achieved. An operable inverter device is provided.

The invention described in claim 4 is particularly advantageous in claim 1 to claim 1.
3. The inverter circuit according to claim 3, comprising a DC power supply and switching elements twice as many as k, wherein the switching element is provided between a plus terminal of the DC power supply and an input terminal of the motor. And by being connected between the negative terminal of the DC power supply and the input terminal of the motor,
An inverter device that can realize low vibration and low noise while suppressing the number of switching elements and realizing compactness and low cost.
To provide.

The invention described in claim 5 is particularly advantageous in claim 1 to claim 1.
By setting k = 3 in the inverter device according to any one of the above items 4, the number of switching elements is as small as 6 stones, and the configuration of the winding of the motor is simple. An inverter device capable of realizing low vibration and low noise is provided.

[Brief description of the drawings]

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

FIG. 2 is a detailed configuration diagram of the electric motor.

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

FIG. 4 is a graph showing each order component of the no-load induced electromotive force (phase voltage).

FIGS. 5A to 5F show switching elements 121 to 121;
126 drive waveform diagram

Fig. 6 (a) Same, no-load induced electromotive force waveform chart (a) Same, current waveform chart (c) Same, machine output waveform chart

FIG. 7 (a) No-load induced electromotive force waveform diagram in embodiment 2 (a) Current waveform diagram (c) Mechanical output waveform diagram

FIG. 8 is a diagram showing a table in which the torque ripple, harmonic ratio, and noise are compared.

FIGS. 9A and 9B show no-load induced electromotive force waveforms in Example 3; FIGS. 9A and 9B show current waveforms; FIGS. 9C and 9C show cogging torque waveforms; FIGS.

FIG. 10 is a configuration diagram of an electric motor according to a fourth embodiment.

FIG. 11 is a circuit diagram of an inverter device according to a conventional technique.

[Explanation of symbols]

102, 103, 104, 196, 197, 198 Windings 150 to 157, 191, 192 Permanent magnets 174a to 1, 210, 211, 212 Grooves 172, 195 Iron core 105, 106, 107, 200, 201, 202 Input terminal 100 Motor 101 Inverter circuit 120 DC power supply 121 to 126 Switching element 130 Positive terminal 131 Minus terminal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Taketoshi Sato 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5H560 AA10 BB04 BB07 BB12 DA02 DC12 DC13 EB01 RR01 SS07 UA02 XA12 5H603 AA01 BB01 BB09 BB10 BB12 CA01 CA05 CB01 CC11 CD01 CD04 CD08 CD14 CD21 5H621 AA02 BB07 BB10 GA01 GA04 GA16 GB08 HH01 5H622 AA03 CA02 CA07 CB06

Claims (5)

[Claims] An electric motor having k input terminals has a k-phase winding and a p-pole permanent magnet, and the winding has an integral number of grooves obtained by dividing p multiplied by k by two. An inverter circuit provided in a concentrated winding on an iron core having
An inverter device for supplying to each phase winding a current in which the sum of the product of the instantaneous value and the current value of the no-load induced electromotive force of the winding of each phase is substantially constant. 2. An electric motor having a k-phase winding and an inverter circuit for supplying a current having a distortion to the winding, wherein the inverter circuit comprises a no-load induced electromotive force and a current of each phase. An inverter device for supplying a current waveform in which the ripple amount of the sum of the products of the instantaneous values is approximately half the ripple generated when a sine-wave current is supplied to the motor. 3. An electric motor having a k-phase winding and an inverter circuit for supplying a distorted current to the winding, wherein the inverter circuit comprises a no-load induced electromotive force and a current of each phase. An inverter device in which the ripple amount of the sum of the products of the instantaneous values is substantially equal to the amplitude of the cogging power of the electric motor. 4. An inverter circuit comprising: a DC power supply;
A switching element having twice the number of switching elements, wherein the switching element is connected between a plus terminal of the DC power supply and an input terminal of the motor, and between a minus terminal of the DC power supply and an input terminal of the motor. 4. The inverter device according to any one of items 3 to 5. 5. The method according to claim 1, wherein k = 3.
An inverter device according to the item.