JP2000308383A - Inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the fifth and seventh time harmonies that contribute to vibration in the maximum degree to realize low vibration and low noise motor operation by determining the power feeding angle to the particular range. SOLUTION: A motor that is connected in three phases by deviating the phases for 120 deg., for example, with one period of space defined as 360 deg. is operated with the 3-phase voltage (U-phase voltage, V-phase voltage, W-phase voltage) having a phase difference of 120 deg. with one period of application voltage defined as 360 deg.. In this case, in the fifth and seventh harmonics that contribute to vibration in the maximum extent, the power feeding angle is obtained from A of the phase angle where the fifth and seventh harmonics becomes 0 at the rise point of the rectangular waveform. The fact that these harmonics are 0 means that a vibrating force is 0 and any vibration is not generated. Namely, the fifth and seventh time harmonics are minimized by setting the power feeding angles to 144 deg.±3 deg. to 154 deg.±3 deg. or 149 deg.±3 deg. with fluctuation of about 3o defined as the allowable range. As a result, the fifth and seventh time harmonics can be minimized to realize the low vibration and low noise motor operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inverter device for optimally controlling a BL motor, a reluctance motor, and an induction motor.

[0002]

2. Description of the Related Art Conventionally, a synchronous motor (hereinafter, abbreviated as a brushless motor) using a permanent magnet as a rotor, and a reluctance motor (a salient pole structure having a salient pole structure) that rotates by changing the magnetic resistance of the rotor depending on the rotor position. When controlling the speed of a motor having a rotor, a motor that changes the magnetic resistance by providing a gap in the rotor, or a motor that changes the magnetic resistance by combining permanent magnets, etc.), the motor is controlled by the rotation speed and load. It is necessary to change the applied voltage, and the control device uses PAM (P
ulsAmplitudeModulation: pulse height value control and PWM (PulsWidthModu)
(pulsation width) control or the like is used.

When controlling a BL motor or a reluctance motor, it is necessary to synchronize the voltage phase according to the position of the rotor, and an advanced rotor position detector of several hundred pulses or more per rotation is used. In this case, a sine wave PWM control that approximates the applied voltage to a sine wave in synchronization with the detected phase is used. Normally, a rotor position detector is used as a magnetized detector for each phase, A sensorless system for detecting a rotor position by detecting an induced voltage of a motor is mainly used, and both a BL motor and a reluctance motor generally have a PWM control or a PAM control which is controlled by a rectangular wave.

When a rectangular wave voltage is applied, conventionally, a voltage called 180 ° energization shown in FIG.
° There were many voltages called energization. This is because when the three-phase motor is operated, if the above-mentioned rotor magnetization detector is used, one pulse of positive and negative signals of the N pole and the S pole is obtained in one cycle corresponding to one phase, and each phase has a phase of 120 °. This is because the polar position of the six modes can be determined per electric cycle because the angle is detected.

[0005] However, both 180 ° conduction and 120 ° conduction have the drawback that vibrations due to the fifth and seventh harmonics are large, and vibration countermeasures are indispensable for blowers and the like that require a quiet sound.

[0006]

SUMMARY OF THE INVENTION The present invention reduces low-vibration by reducing fifth and seventh-order time harmonics which most contribute to vibration among harmonic components inherently included in a rectangular wave voltage. ,
An object of the present invention is to provide an inverter device that performs low-noise motor operation.

[0007]

The inverter device of the present invention operates a BL motor and a reluctance motor. The inverter device controls the fifth-order time harmonic component by setting the energization angle to 144 ° ± 3 °. It can be minimized, enabling low vibration and low noise.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The inverter device of the present invention
In the inverter device for operating the L motor and the reluctance motor, the fifth time harmonic component can be minimized by setting the energization angle to 144 ° ± 3 °. Further, in the inverter device for operating the BL motor and the reluctance motor, the seventh time harmonic component can be minimized by setting the energization angle to 154 ° ± 3 °. In addition, in the inverter device for operating the BL motor and the reluctance motor, the sum of the fifth and seventh order time harmonics can be minimized by setting the energization angle to 149 ° ± 3 °.

Further, in an inverter device that operates an induction motor with a rectangular wave, the fifth time harmonic component can be minimized by setting the energization angle to 144 ° ± 3 °. Further, in an inverter device that operates an induction motor with a rectangular wave, the seventh time harmonic component can be minimized by setting the energization angle to 154 ° ± 3 °. In addition, in an inverter device that operates an induction motor with a rectangular wave, the energization angle can be set to 149 ° ± 3 °, and the sum of the fifth and seventh time harmonics can be minimized.

[0010]

This embodiment is directed to an inverter device for operating a BL motor and a reluctance motor in which the energization angle is set to 144.
This is an inverter device with a degree of ± 3 °, 154 ° ± 3 ° or 149 ° ± 3 °, and operates a low vibration and low noise motor by minimizing the fifth and seventh time harmonic components. An inverter device is provided.

The energization angle is 144 ° ± 3 °, 154 ° ± 3 °
The reason why the time harmonic component is minimized by setting the angle to 149 ° ± 3 ° is described below. 180 ° as shown in FIG.
When a square wave in which a voltage pulse rises at a phase angle A from the position of 0 ° of the square wave of FIG.
If only the in term exists and the harmonic order is n, n is only an odd number (n = 1, 3, 5, 7,...). Then, one cycle of the applied voltage is set to 360 ° in a three-phase connected motor in which one cycle is spatially shifted by 120 ° and one cycle is set to 360 °.
As a three-phase voltage having a phase difference of 120 ° (U in FIG. 1).
(Displayed as phase voltage, V-phase voltage, and W-phase voltage), the third-order multiple harmonic components cancel each other out and no longer exist. Therefore, the harmonic order n is 1, 5, 7, 1
1, 13,... The fifth and seventh harmonics are components that generate vibration six times the fundamental frequency, and the larger the value, the greater the vibration (the stronger the excitation force).

The magnitude of the voltage of the n-th harmonic component is 18
If V (n) is a ratio where the magnitude of the fundamental wave component at the time of 0 ° conduction is 1 (100%), the equation (1) is obtained.

[0013]

(Equation 1)

By expanding this equation, one cycle of the voltage waveform is set to 36
0 °, the fifth harmonic that contributes most to vibration and the seventh harmonic
In the case of the fifth harmonic, the component of the fifth harmonic component becomes 0 if the rising edge of the rectangular wave has the phase angle A of 18 ° (90/5 °) (Equation (2)). It can be seen that the component of the harmonic is 0 if A is 12.86 ° (90/7 °) (Equation (3)). The fact that this component is 0 means that when the motor rotates, the exciting force of its temporal harmonic is 0, and vibration caused by the temporal harmonic does not occur.

[0015]

(Equation 2)

[0016]

(Equation 3)

Therefore, in terms of the conduction angle, the conduction angle at which the fifth harmonic component is minimized is 180 ° -18 ° × 2.
= 144 °, and the minimum of the seventh harmonic component is 180 ° -12.86 ° × 2 = 154.3 °.

Next, the equation (1) is developed, and the phase angle A is expressed as X
FIG. 2 shows the magnitude of each harmonic on the Y-axis.
From this, it can be seen that when the above-described phase angles are selected, the components of the fifth harmonic and the seventh harmonic are zero.

Further, in FIG. 2, the first harmonic component is called a fundamental wave component, which is a fundamental wave that contributes to the rotation speed of the motor, and each harmonic component with respect to the fundamental wave becomes a vibration component. The value obtained by dividing those contents by the fundamental wave means the distortion factor, and the smaller the value is, the smaller the vibration is. Here, the square root of the sum of the squares of the effective values of the harmonic components is the distortion component, and the value obtained by dividing the distortion component by the magnitude of the fundamental wave is the distortion factor. Is the phase angle of 15.4
It can be seen that it is 75 ° and the energization angle is 149.05 °.

Note that when 180 ° is energized in the conventional example, the equation (1)
Is 0 °, the component of the fifth harmonic is 20% from the component of the fundamental wave, and the component of the seventh harmonic is 14.3% from the formula (5). The absolute value is the same value from the expressions (6) and (7) assuming that A in the expression (1) is 30 ° for the 120 ° conduction as well. It can be seen from equation (8) that the distortion factor for the fundamental wave is 24.6%.

[0021]

(Equation 4)

[0022]

(Equation 5)

[0023]

(Equation 6)

[0024]

(Equation 7)

[0025]

(Equation 8)

On the other hand, if the conduction angle is 144 °, the fifth-order component is 0 as described above, but the seventh-order component is 8.4% and the distortion factor is 8.4% by the same calculation. If the conduction angle is 154.3 °, the fifth harmonic component is 8.7%,
The component of the seventh harmonic is 0, and the distortion factor is 8.7%. Fifth
Conduction angle 149.0 at which the distortion rate by the second and seventh orders is the minimum value
In the case of 5 °, the fifth harmonic component is 4.3%, the seventh harmonic component is 4.5%, and the distortion is 6.3%.

Even when the phase angle A in FIG. 1 is determined to be 15 ° (energization angle 120 °), the voltage waveform is a dead time control for preventing simultaneous ON of the switching transistors due to a time delay when the switching transistor is OFF or a circuit delay. 2, the variation of the angle of about several degrees from FIG. 2 does not significantly increase the increase of the vibration. Therefore, the allowable angle of the phase angle A is set so that the maximum rotation speed of the motor is 6000 r / min (100 r / min). s) If the motor is magnetized with eight poles, one cycle of the time wave is 2.5 mS, and the dead time for preventing the inconvenient simultaneous ON of the switching transistors due to the time delay when the switching transistor is OFF is usually about 20 μS. Is required, 20 μS is 3 ° when the cycle is 360 °, and the present application allows a variation of about 3 °.

As described above, when a rectangular wave voltage is applied to the motor, if the conduction angle is 144 °, a low-vibration waveform having zero motor vibration component due to the fifth harmonic can be provided.
° provides a low-vibration waveform with zero vibration component of the motor due to the 7th harmonic, and 149.05 ° provides a voltage waveform with minimum vibration due to both the 5th and 7th harmonic components. Can be provided.

Note that the inverter device for the induction motor is P
Examples of operating with AM control are increasing, mainly for air conditioners, with the expectation of energy saving. However, the inverter device of the induction motor does not need the magnetization detector for the aforementioned BL motor or reluctance motor, and feedback from the sensor Although there is no open control, the concept of the time harmonic of the rectangular wave is the same, and the reduction of the vibration by the time harmonic is the same in the waveform of the present invention.

Similarly, the above embodiment is based on the premise of the PAM control from FIG. 1, but the same applies to the implementation with the equal width PWM control.

FIG. 2 shows that the fifth harmonic component has a phase angle A of 54 ° and the seventh harmonic component has a phase angle A of 54 °.
Becomes zero when the angles are 38.57 ° and 64.29 °, and the effect of the vibration reduction is the same, but the component of the fundamental wave is greatly reduced, and the motor applied voltage is reduced at the basic rotation speed of the motor. It is necessary to reduce the induced voltage constant, which is not advantageous because the current capacity of the switching transistor increases because the motor current increases when the same load torque is applied.

[0032]

As described above, when the three-phase motor is operated at the conduction angle according to the present invention, the vibration of the motor due to the time harmonic is reduced, and an inverter device for operating the motor with low vibration and low noise can be provided.

[Brief description of the drawings]

FIG. 1 is a voltage waveform diagram of the present embodiment.

FIG. 2 is a diagram showing the magnitudes of voltages of the same phase angle and harmonic components.

FIG. 3 is a voltage waveform diagram of a conventional example with 180 ° conduction.

FIG. 4 is a diagram showing a voltage waveform at 120 ° conduction in a conventional example.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) LL15

Claims (6)

[Claims] 1. An inverter device for operating a BL motor and a reluctance motor, wherein an energization angle is set to 144 ° ± 3.
° Inverter device. 2. An inverter device for operating a BL motor and a reluctance motor, wherein the energization angle is set to 154 ° ± 3.
° Inverter device. 3. An inverter device for operating a BL motor and a reluctance motor, wherein an energization angle is set to 149 ° ± 3.
° Inverter device. 4. An inverter device for operating an induction motor with a rectangular wave, wherein a conduction angle is set to 144 ° ± 3 °. 5. An inverter device for operating an induction motor with a rectangular wave, wherein the conduction angle is 154 ° ± 3 °. 6. An inverter device for operating an induction motor with a rectangular wave, wherein a conduction angle is set to 149 ° ± 3 °.