JP6000801B2 - Motor control device and air conditioner using the same - Google Patents

Description

  The present invention relates to a control method of a motor control device and an air conditioner using the same. In particular, the present invention relates to a reduction in sound caused by a fan motor.

Conventionally, in a small fan motor used in an air conditioner, noise generated at a specific rotation speed due to resonance between the rotor and the fan has been a problem. In order to solve the problem of noise due to resonance, the vibration is reduced by providing an anti-vibration rubber on the rotor part or an anti-vibration rubber on the fan shaft receiving part.
One of the causes is current waveform distortion due to the difference between the induced voltage distortion of the motor and the applied voltage, and various methods have been proposed to eliminate this current waveform distortion.
For example, Patent Document 1 discloses a technique in which a voltage that cancels torque ripple generated due to distortion of an induced voltage is created in advance as an induced voltage ripple table and added to a command voltage.
In Patent Document 2, there is a control method for switching a modulation method according to a map of torque and rotation speed or two-dimensional coordinates of id current (d-axis) and iq current (q-axis) in order to realize high-efficiency operation. It is disclosed.

JP 2008-219966 A JP 2005-229676 A

However, the method of providing the anti-vibration rubber for reducing the resonance noise of the fan and the rotor has a problem that the structure of the motor and the fan is complicated and the cost is increased.
Further, the inventor has confirmed through experiments that the resonance sound of the fan and the rotor does not disappear with the current sine wave technology disclosed in Patent Document 1.
Further, the present inventor has confirmed through experiments that the method of switching the modulation method disclosed in Patent Document 2 may or may not eliminate the resonance sound of the fan and the rotor.

  Therefore, the present invention solves such problems, and the object of the present invention is to achieve high efficiency by reducing the noise caused by the resonance between the fan and the rotor, even if the motor or fan is not provided with an anti-vibration rubber. Is to provide a simple motor control device.

In order to solve the above-described problems and achieve the object of the present invention, the present invention is configured as follows.
That is, the motor control device of the present invention is connected to a DC power source, converts the DC power of the DC power source into AC power of variable voltage and variable frequency, and rotationally drives a load and an inverter for driving and controlling a three-phase motor. A vector control unit that calculates a voltage applied to the three-phase motor, a high-order component generation unit that calculates a high-order component of a fundamental wave of an applied voltage of the vector control unit, and an applied voltage calculated by the vector control unit A voltage addition unit for adding higher-order components calculated by the higher-order component generation unit and a plurality of modulation methods including a fixed two-phase modulation method, and controlling the pulse width of the inverter based on a signal from the voltage addition unit And a modulation method selection unit that selects the plurality of modulation methods included in the PWM pulse generation unit, based on the rotation information of the three-phase motor obtained by the vector control unit. When the resonance frequency component exceeds a predetermined range, the modulation method selection unit selects one of the plurality of modulation methods, and the PWM pulse generation unit controls the inverter with the selected modulation method. The resonance noise that resonates at a frequency (6m + 3) times (m is a positive integer) times the rotational frequency of the three-phase motor is reduced.
Other means will be described in the embodiment for carrying out the invention.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is not a motor and fan which provided the vibration proof rubber, the highly efficient motor control apparatus which reduced the sound by the resonance of a fan and a rotor can be provided.

It is a figure which shows the internal structure of the motor control apparatus which concerns on 1st Embodiment of this invention, and the relationship between this DC motor control apparatus, a power supply, a three-phase alternating current synchronous motor, and load. In 1st Embodiment of this invention, it is a figure which shows the method of adding the high-order component of a high-order component production | generation part to the fundamental wave of a vector control part using a rotation coordinate system in a voltage addition part. In 1st Embodiment of this invention, it is a figure which shows the method of adding the high order component of a high order component production | generation part to the fundamental wave of a vector control part using a fixed coordinate system in the voltage addition part. It is a figure which shows an example of the characteristic with respect to the rotation speed of the noise of a fan. It is a figure which shows an example of the frequency spectrum of the noise of a fan in case the rotation speed of a motor is 450min- ¹ . It is a figure which shows an example of the frequency spectrum of the noise of a fan in case the rotation speed of a motor is 510min- ¹ . It is a figure which shows an example of the frequency spectrum of the noise of a fan in case the rotation speed of a motor is 600min- ¹ . It is a figure which shows an example of the frequency spectrum of the noise of a fan in case the rotation speed of a motor is 650min- ¹ . In a first embodiment of the present invention, _G 5 = 3% at an applied type high-order components, φ ₅ = 60 _degrees, G 7 = _5%, shows an example of a spectrum of the noise in the case of phi ₇ = 20 degrees It is. It is a figure which shows an example of the waveform when the spectrum of FIG. 9 was shown, and the waveform which performed the FFT analysis of the motor current, (a) is a waveform of a motor terminal voltage, (b) is a waveform of a motor current, ( c) is a waveform obtained by performing FFT analysis of the motor current. It is a figure which shows an example of the waveform which performed the FFT analysis of the motor waveform (voltage, current) and motor current at the time of operating a motor by the lower stationary phase 120 degree | times switching system, (a) is a waveform of a motor terminal voltage, (B) is a waveform of the motor current, and (c) is a waveform obtained by performing FFT analysis of the motor current. It is a figure which shows the whole structure of the motor control apparatus of the comparative example 1. It is a figure showing the outline of the waveform in a fixed coordinate system in case an induced voltage waveform is an ideal sine wave, (a) shows an induced voltage, (b) shows the command voltage to apply, (c) shows motor current. ing. It is a figure showing the outline of the waveform in a fixed coordinate system when an induced voltage waveform is distorted, (a) shows an induced voltage, (b) shows an applied command voltage, and (c) shows a motor current. It is a figure showing the outline of the waveform in the rotation coordinate system on the basis of the magnetic flux of a permanent magnet in case the induced voltage waveform is an ideal sine wave, (a) is an induced voltage, (b) is the command voltage to apply, (C) shows the motor current. It is a figure showing the outline of the waveform in the rotation coordinate system on the basis of the magnetic flux of a permanent magnet when an induced voltage waveform is distorted, (a) is an induced voltage, (b) is a command voltage to apply, (c) is The motor current is shown. It is a figure which shows the general | schematic waveform in the fixed coordinate at the time of adding the higher-order component of an induced voltage to an applied voltage, (a) is an induced voltage, (b) is the command voltage to apply, (c) shows a motor current. ing. It is a figure which shows the general | schematic waveform in a rotation coordinate system at the time of adding the higher order component of an induced voltage to an applied voltage, (a) is an induced voltage, (b) is the command voltage to apply, (c) is a motor current. Show. It is a figure which shows the voltage waveform of U phase, V phase, and W phase in general three phase modulation. It is a figure which shows the voltage waveform of U phase, V phase, and W phase in the stationary phase 60 degree switching system which is a two-phase modulation system. It is a figure which shows the voltage waveform of the U phase in the upper stationary phase 120 degree switching system which is a two-phase modulation system, a V phase, and a W phase. It is a figure which shows the voltage waveform of U phase, V phase, and W phase in the lower stationary phase 120 degree | times switching system which is a two-phase modulation system. It is a figure which shows the internal structure of the motor control apparatus which concerns on 2nd Embodiment of this invention, and the relationship between this DC motor control apparatus, DC power supply, a three-phase motor, and a fan. It is a figure which shows the internal structure of the motor control apparatus which concerns on 3rd Embodiment of this invention, and the relationship between this DC motor control apparatus, DC power supply, a three-phase motor, and a fan. It is a figure which shows the waveform which performed the analysis of the motor terminal voltage and motor current at the time of implementing the application of a 5th-order component and the fixed phase 60 degree switching system of two-phase modulation in 510min- ¹ , and (FFT analysis), a) is a waveform of the motor terminal voltage, (b) is a waveform of the motor current, and (c) is a waveform obtained by performing FFT analysis of the motor current. It is a figure which shows the noise spectrum of the fan at the time of the measurement conditions of the motor of FIG. It is a figure which shows the structure of the air conditioner which concerns on 4th Embodiment of this invention.

  EMBODIMENT OF THE INVENTION The form for implementing invention of this application (henceforth "embodiment") is demonstrated with reference to drawings below.

(First embodiment)
A motor control device according to a first embodiment of the present invention will be described with reference to FIGS.

[Configuration of motor controller: Part 1]
FIG. 1 shows an internal configuration of a motor control device 11 according to the first embodiment of the present invention, a motor control device 11, a DC power source 12, a three-phase AC synchronous motor (as appropriate “motor” or “three-phase motor”). It is a figure which shows the relationship between (abbreviated) 13 and load (fan) 14.
In FIG. 1, the motor control device 11 includes an inverter 15 that is a DC-AC power converter and a control device 17 that controls the inverter 15.
The control device 17 includes a PWM (Pulse Width Modulation) pulse generation unit 24, a vector control unit 21, a high-order component generation unit 22, and a voltage addition unit 23.
A feature of the motor control device 11 of the first embodiment is that the control device 17 includes a high-order component generation unit 22, and when the control device 17 performs PWM control of the inverter 15, the high-order component generation unit 22 to the voltage addition unit 23. It is to add the higher order component of the induced voltage. By this method, noise due to resonance between the motor 13 and the fan 14 as a load is removed.
Before describing details of the motor control device 11 of the first embodiment, which is characterized by a method for removing noise due to resonance, noise due to resonance between the motor and the fan will be described first. The motor control device 11 of one embodiment will be described in detail.

<Fan noise>
The noise generated by the fan 14 when the fan 14 (FIG. 1) is driven by the motor 13 (FIG. 1) will be described.
FIG. 4 is a diagram illustrating an example of characteristics of the noise of the fan 14 with respect to the rotation speed. 2 and 3 will be described later.
In FIG. 4, the horizontal axis is the rotational speed [min ⁻¹ ], and the vertical axis is the noise [dB]. The rotation speed [min ⁻¹ ] is the rotation speed / minute. Also, it corresponds to rpm (rotation per minute). In the following description, for example, 510 rpm / min is simply expressed as 510 min ⁻¹ .
Fan noise 14 in FIG ^4, 250min ^-1, 510min ^-1, has appeared in the vicinity of a particular rotational speed of the fan 14 as 650 min ^-1.
Next, frequency spectra at these specific rotation speeds are shown in FIGS.

FIG. 5 is a diagram illustrating an example of a frequency spectrum of noise of the fan 14 when the rotation speed of the motor 13 is 450 min ⁻¹ .

FIG. 6 is a diagram illustrating an example of a frequency spectrum of noise of the fan 14 when the rotational speed of the motor 13 is 510 min ⁻¹ .

FIG. 7 is a diagram illustrating an example of a frequency spectrum of noise of the fan 14 when the rotational speed of the motor 13 is 600 min ⁻¹ .

FIG. 8 is a diagram illustrating an example of a frequency spectrum of noise of the fan 14 when the rotation speed of the motor 13 is 650 min ⁻¹ .

  5 to 8, the horizontal axis represents frequency [Hz] and the vertical axis represents noise [dB]. On the horizontal axis, the measurement points are taken in 1/3 octave units. Therefore, the third measurement point from the 200 Hz measurement point is 400 Hz, but it is 398 Hz due to the accumulation of fractions on the setting at the time of measurement. Similarly, 794 Hz, 1585 Hz, 3162 Hz, 6310 Hz, and 12589 Hz respectively correspond to 800 Hz, 1600 Hz, 3200 Hz, 6400 Hz, and 12800 Hz, respectively.

In the frequency analysis results of FIGS. 5 to 8, in 600 min ^-1 Metropolitan of 450Min ^-1 and 7 in FIG. 5, is not observed measurement point noise is projected.
However, at 510 min ⁻¹ in FIG. 6, there are measurement points at which noise protruded at 200 Hz and 316 Hz. Further, at 650 min ⁻¹ in FIG. 8, there is a measurement point where noise protruded at 251 Hz.
Thus, the resonance sound of the fan 14 and the motor 13 appears in the vicinity of 200 to 300 Hz.
If the rotation speed is 510 min ⁻¹ , the motor is a three-phase AC synchronous motor. Therefore, if the motor has 8 poles, the electric frequency of the motor is 34 Hz [510 / {60 × (2 / 8)}]. Sound is generated by the excitation torque near the sixth-order component of 204 Hz (34 × 6, corresponding to 200 Hz in FIG. 6) and the ninth-order component of 306 Hz (34 × 9, corresponding to 316 Hz in FIG. 6) with 34 Hz as a fundamental frequency. You can see that
Therefore, in order to eliminate the resonance noise between the fan 14 and the motor (motor rotor) 13, measures against these higher-order components are taken.

[Configuration of motor controller: Part 2]
The configuration of the motor control device 11 according to the first embodiment of the present invention shown in FIG. 1 will be described again in detail.

<Relationship between motor controller and DC power supply, motor, fan>
As described above, FIG. 1 is a diagram illustrating the configuration of the motor control device 11 according to the first embodiment of the present invention and the relationship among the DC power supply 12, the motor 13, and the fan (load) 14.
In FIG. 1, a motor control device 11 receives DC power from a DC power supply 12 and converts it into three-phase AC power. Further, the motor (three-phase AC synchronous motor) 13 is supplied with the three-phase AC power from the motor control device 11, is driven and controlled to rotate, and rotates the fan 14.
Next, details of the motor control device 11 will be described.

<Motor control device>
In FIG. 1, as described above, the motor control device 11 includes the inverter 15 (power converter) that converts DC power into three-phase AC power of variable voltage and variable frequency, and the control device 17 that controls the inverter 15. It is configured. Further, a DC bus current detection circuit 16 is provided in the DC power source of the inverter 15.

<Inverter>
The inverter 15 includes a power conversion main circuit 51 including a diode element connected in reverse parallel to a semiconductor switching element such as an IGBT (Insulated Gate Bipolar Transistor), and a PWM pulse signal from a PWM pulse generation unit 24 described later. And a gate driver 52 that generates a gate signal to the IGBT (Sup, Sun, Svp, Svn, Swp, Swn) of the power conversion main circuit 51 based on 17A.
The IGBTs (Sup, Sun) constituting the legs by connecting the IGBTs in series are connected between the DC power sources 12, and the connection points of the upper arm (Sup) and the lower arm (Sup) are U-phase AC. Output terminal.

Similarly, IGBTs (Svp, Svn) that are connected in series to form a leg are connected between the DC power supplies 12, and the connection points of the upper arm (Svp) and the lower arm (Svn) are V-phase AC. Output terminal.
Further, IGBTs (Swp, Swn) that are connected in series and constitute a leg are connected between the DC power supplies 12, and the connection points of the upper arm (Swp) and the lower arm (Swn) are the AC of the W phase. Output terminal.
When the control device 17 appropriately controls the above IGBTs (Sup, Sun, Svp, Svn, Swp, Swn) via the gate driver 52, the DC power of the DC power supply 12 can be changed to a variable voltage variable frequency. Three-phase AC power (three-phase AC voltages Vu, Vv, Vw, three-phase AC currents Iu, Iv, Iw) is output from the U-phase, V-phase, and W-phase AC output terminals.

"Control device"
The control device 17 includes a PWM pulse generation unit 24, a vector control unit 21, a high-order component generation unit 22, and a voltage addition unit 23.
The vector control unit 21 generates a fundamental wave application voltage command to the permanent magnet synchronous motor 13 based on DC bus current information (appropriately expressed as “phase current information”) 16A detected by the DC bus current detection circuit 16. 21B and motor rotation speed / phase information 21A of the permanent magnet synchronous motor 13 are calculated.
The high-order component generator 22 outputs the high-order component 22A of the induced voltage of the permanent magnet synchronous motor 13 to the voltage adder 23 based on the motor rotation speed / phase information (rotation information) 21A.
The voltage adding unit 23 adds the higher-order component 22A of the induced voltage to the fundamental wave applied voltage command 21B and outputs the applied voltage command 23A.

Further, the PWM pulse generator 24 converts the inverter 15 into a PWM pulse signal 17A for controlling the pulse width based on the applied voltage command 23A and the internal carrier signal.
The vector control of the vector control unit 21 is, for example, as described in Non-Patent Document 1, “Examination of a New Vector Control Method for a High-Speed Permanent Magnet Synchronous Motor”, Electrotechnical D, Vol. 129 (2009) No. 1 pp. .36-45 "and Non-Patent Document 2," Simple Vector Control of Position Sensorless Permanent Magnet Synchronous Motors for Home Appliances, "Electrology D, Vol.124 (2004) No.11 pp.1133-1140 This can be achieved by using the scheme shown.

<< DC bus current detection circuit >>
DC bus current detecting circuit 16 is connected to the negative side of the DC bus of the DC power source 12, U-phase, V-phase, pulsating of W phase to obtain a phase current information from the DC bus current I _DC were mixed. The acquired phase current information is output to the vector control unit 21 as DC bus current information (phase current information) 16A.
In addition, the method of acquiring phase current information is possible by the system etc. which are disclosed by Unexamined-Japanese-Patent No. 2004-48886 as patent document 3, for example.

[Operation of higher-order component generator and voltage adder]
In the first embodiment, in order to reduce noise, a high-order component is applied by a high-order component generation unit 22 and a voltage addition unit 23 of induced voltage described below.
Hereinafter, the operations of the high-order component generation unit 22 that generates the high-order component 22A of the induced voltage and the voltage addition unit 23 that adds the high-order component 22A to the fundamental wave applied voltage command 21B will be described with reference to FIGS. 17 and with reference to FIG.

<Generation of higher order components>
The high-order component generation unit 22 generates a high-order component based on the motor rotation speed / phase information 21A using the values of G and φ in (Expression 1) and (Expression 2) described later, which are set in advance, The high-order component 22A is output to the voltage adding unit 23.

<Addition to applied voltage>
In the voltage addition unit 23, the fundamental wave applied voltage command 21 B output from the vector control unit 21 and the high-order component 22 A of the induced voltage output from the high-order component generation unit 22 are added and output to the PWM pulse generation unit 24. .
As a specific configuration, there are addition in a rotating coordinate system and addition in a fixed coordinate system. Next, these methods will be described in order.

《Addition in rotating coordinate system》
A method of addition in the rotating coordinate system will be described with reference to FIG.
FIG. 2 shows that in the first embodiment of the present invention, the higher-order component of the higher-order component generator 22 (the higher-order component 22A of the induced voltage) is changed to the fundamental wave (fundamental wave applied voltage command 21B) of the vector controller 21. It is a figure which shows the method of adding using the rotation coordinate system in the voltage addition part.
In FIG. 2, the vector control unit 21 is a rotating coordinate system based on the magnet flux direction (d axis) of the motor rotor based on the phase current information 16 </ b> A and based on the d axis and a perpendicular direction (q axis). On the dq coordinate axis, a fundamental wave applied voltage command 21B (Vd ^* , Vq ^* ) and motor rotation speed / phase information (rotation information) 21A are output. Note that Vd ^* is the fundamental wave applied voltage command 21B (FIG. 1) relating to the d-axis and Vq ^* is related to the q-axis.

The higher-order component generation unit 22 generates higher-order components 22A-d (d-axis) and 22A-q (q-axis) on the dq coordinate axis based on the motor rotation speed / phase information 21A from the vector control unit 21. Note that the high-order components 22A-d and 22A-q correspond to the high-order component 22A in FIG.
The voltage adder 23 adds the fundamental wave applied voltage command (Vd ^* ) and the higher-order component 22A-d on the d-axis, and outputs a d-axis applied voltage command 23A-d.
The voltage adding unit 23 adds the fundamental wave applied voltage command (Vq ^* ) and the higher-order component 22A-q on the q axis, and outputs a q-axis applied voltage command 23A-q.
The applied voltage commands 23A-d and 23A-q are converted into U-phase, V-phase, and W-phase components by a converter (not shown), and input to the PWM pulse generator 24 (FIG. 1).

《Addition in fixed coordinate system》
The addition method in the fixed coordinate system will be described with reference to FIG.
FIG. 3 shows that in the first embodiment of the present invention, the higher-order component of the higher-order component generator 22 (the higher-order component 22A of the induced voltage) is changed to the fundamental wave (fundamental wave applied voltage command 21B) of the vector controller 21. It is a figure which shows the method of adding using the fixed coordinate system in the voltage addition part.
In FIG. 3, the vector control unit 21 is based on the phase current information 16A, and the three-phase AC fundamental wave applied voltage command 21B (Vu ^* , Vv ^* , Vw ^* ) in the fixed coordinate system and the motor rotation speed / phase information. 21A is output.
The high-order component generator 22 generates high-order components 22A-U, 22A-V, and 22A-W for each phase based on the motor rotation speed / phase information 21A from the vector controller 21.
The voltage adding unit 23 outputs a three-phase AC fundamental wave applied voltage command 21B (Vu ^* , Vv ^* , Vw ^* ) of a fixed coordinate system and higher-order components 22A-U, 22A-V, 22A-W to each phase ( U, V, and W) are added to output applied voltage commands 23A-U, 23A-V, and 23A-W, respectively.

[Reduction of 6th vibration]
Next, a method for reducing the resonance noise of the fan 14 and the rotor (the rotor of the motor 13) generated at the sixth order of the motor rotation speed will be described.
The resonance caused by the fan 14 and the rotor (13) is caused by vibration in the rotation direction, and the voltage or current of each phase of the motor is different from the coordinate axis. The resonance of the fan and the rotor is related to the component of the coordinate axis of the rotating magnetic field resulting from the synthesis of three phases having different phases every 120 degrees (2π / 3) of the motor. Therefore, it is appropriate to take measures to reduce resonance noise by converting to the dq coordinate system of the rotating coordinate system instead of the voltage of each phase of the three-phase motor (motor).

In general, the (3m-1) th order component and the (3m + 1) th order component in each phase of the three-phase motor are converted into a 3mth order component of the dq coordinate system. Here, m is a positive integer.
The 3m-order component is generated by the action of the sum of the fundamental wave (first-order component) and the (3m-1) -order component. Further, a 3m-order component is generated by the action of the difference in the synthesis of the fundamental wave (first-order component) and the (3m + 1) -order component.
In order to develop this transformation and eliminate the 6th order component (m = 2) in the dq coordinate system, that is, the rotational coordinate system, the induced voltage component is applied to the applied voltage of each phase (U, V, W) of the three-phase motor. The inventors devised adding a quintic component and a quintic component (m = 2). This will be described below.

<Application formula for higher-order components>
In this case, the applied equations E ₅ and E ₇ for the induced voltage primary component E ₁ and the high-order component are the following (Equation 1), (Equation 2), and (Equation 3).
<< Formula of primary component >>

<< Fourth-component application formula >>
The expression for applying the fifth-order component to each phase (U, V, W) is as follows.

<< Applying formula for 7th order component >>
Moreover, about the application formula of the 7th order component to each phase (U, V, W), it becomes the following formula | equation.

In (Expression 1), (Expression 2), and (Expression 3), ω: motor electrical angular frequency, K _e : induced voltage constant, θ: phase, G ₅ : ratio of fifth-order wave amplitude to induced voltage fundamental wave amplitude , G ₇ : ratio of seventh-order wave amplitude to induced voltage fundamental wave amplitude, φ ₅ : phase difference between fundamental wave component and fifth-order component, and φ ₇ : phase difference between fundamental wave component and seventh-order component.
The following (Expression 4) is obtained by performing dq conversion used in vector control on the primary component, the fifth order component, and the seventh order component represented by (Expression 1), (Expression 2), and (Expression 3). , (Equation 2) and (Equation 3), the fifth order component and the seventh order component can be the sixth order component of the dq coordinate system (torque system). This sixth-order component acts as a torque that cancels the excitation torque, and the sixth-order component of the rotational speed can be eliminated.

<< Conversion to dq coordinate system >>
From the induced voltage primary component E1 and the high order components E5 and E7, the voltages Ed and Eq in the dq coordinate system are converted by the following (Equation 4).

<Reduction of various high-order components>
Further, (Expression 1) and (Expression 2) are expressed by the ratio G (G ₅ , G ₇ ) to the amplitude of the induced voltage and the phase difference φ (φ ₅ , φ ₇ ) to the induced voltage component. And φ can be changed to freely apply higher order components.

<< Reduction of 6th order sound at 510 min ^-1 >>
Next, an experimental example for reducing the sixth order sound at 510 min ⁻¹ is shown.
The inventors experimentally changed the values of G ₅ , G ₇ , φ ₅ , and φ ₇ , and G ₅ = 3%, φ ₅ = 60 degrees, G ₇ = 5%, and φ ₇ = 20 degrees. Has been found to be effective in reducing the sixth order sound, that is, approximately 200 Hz.
FIG. 9 is a diagram illustrating an example of a noise spectrum when G ₅ = 3%, φ ₅ = 60 degrees, G ₇ = 5%, and φ ₇ = 20 degrees in the high-order component application formula. The horizontal axis represents frequency [Hz], and the vertical axis represents noise [dB]. On the horizontal axis, the measurement points are taken in 1/3 octave units.
In FIG. 9, the protruding measurement point of the 200 Hz noise seen in FIG. 6 disappears. Although there is a spectrum at 200 Hz, a measurement result that is not significantly different from the spectrum around 200 Hz is obtained. Therefore, it shows that there was an effect in the reduction of the 6th order sound (approximately 200 Hz).

FIG. 10 is a diagram showing an example of a waveform obtained by performing FFT (Fast Fourier Transform) analysis of the motor waveform (voltage, current) and motor current when the spectrum of FIG. 9 is shown. A waveform of the terminal voltage, (b) is a waveform of the motor current, and (c) is a waveform obtained by performing an FFT analysis of the motor current.
In addition, the horizontal axis of FIGS. 10A and 10B is a transition of time, and the vertical axis is a voltage value and a current value, respectively. In FIG. 10C, the horizontal axis represents frequency, and the vertical axis represents the ratio of current components.
Looking at the FFT in FIG. 10C, the fifth-order component is largely included. However, since the fifth-order component of this motor does not resonate with the fan (it is attenuated by the fan), there is no problem even if it remains.

<< Reduction of 12th order sound at 250 min ^-1 >>
Next, a 12th-order sound reduction method at 250 min ⁻¹ will be described.
In FIG. 4, there is a protruding point of noise at 250 min ⁻¹ . Although the spectrum is not shown, the noise is approximately 200 Hz.
When the number of poles of the motor is eight, a sound of approximately 200 Hz at 250 min ⁻¹ corresponds to 16.67 Hz [250 / {60 × (2/8)}] at the motor electrical frequency.
Therefore, the noise is caused by the 12th order (≈200 / 16.67) high order component. A method of reducing this 12th order higher order component will be described.
As with the 6th order, the 11th and 13th order higher order components are applied to the three-phase motor for the 12th order due to the relationship between the sum and difference of the higher order components and the fundamental wave.
For the 12th order, by applying both or 11th order and / or 13th order higher order components, the resonance noise of the fan and rotor having a frequency 12 times the fan speed can be reduced. it can.

<< Reduction of 6m order sound >>
The 6th and 12th orders have been described above.
Further, when the sine wave drive is performed, the even order of each phase that is symmetric within one period disappears.
Accordingly, the method described in the first embodiment is effective in the 6th order (where m is a positive integer, that is, m = 1, 2, in general) where m is a positive integer in addition to the 6th order and 12th order described above. 3 ...) can be reduced.

<Soft start and soft end when applying>
A method of applying the first (start) and the last (end) when applying a higher-order component will be described.
In the high-order component generation unit 22, when the rotational speed at which the high-order component is applied is reached, the amplitude value of the high-order component is gradually increased from 0 to a predetermined amplitude (soft start). For example, in (Equation 1) and (Equation 2) in which fifth-order and seventh-order components are applied, this corresponds to gradually increasing the coefficients of G ₅ and G ₇ (ratio to the induced voltage fundamental wave amplitude).
Further, when the rotational speed at which the high-order component is not applied is reached from the state where the high-order component is applied, the amplitude value of the high-order component is gradually reduced from a predetermined amplitude to 0 (soft end).
By adopting the soft start and soft end when applying this higher-order component, there is no shock when the application of the higher-order component is started and finished, and stable control is achieved.

<Effects of First Embodiment>
By applying a 6m-order higher-order component with a predetermined phase and amplitude according to the first embodiment shown in FIG. 1, it is possible to reduce the resonance noise of the fan and rotor having a frequency 6 m times the motor rotation speed.

≪Comparative example 1≫
Next, as Comparative Example 1, a method of controlling a current waveform in a sine wave shape by a current controller will be described. This method is described in Non-Patent Document 1, "Examination of New Vector Control Method for Permanent Magnet Synchronous Motor for High Speed", Electron Theory D, Vol.129 (2009) No.1 pp.36-45, etc. The same or similar techniques are disclosed.

<Method to control current waveform to sine wave>
First, a method of controlling a current waveform in a sine wave shape by a current controller will be described with reference to FIGS.
FIG. 12 is a diagram illustrating an overall configuration of the first comparative example. In addition, what attached | subjected the code | symbol same as FIG. 1 is abbreviate | omitted as what has the same function, and abbreviate | omits description.
12 differs from FIG. 1 in that the control device 18 includes a vector control unit 21 and a PWM pulse generation unit 24 (output is a PWM pulse signal 18A). That is, the high-order component generation unit 22 and the voltage addition unit 23 in FIG. 1 do not exist in FIG.
In the control device 18, the vector control unit 21 performs an operation based on the phase current information reproduced from the DC bus current information 16A. That is, this is a method in which no higher-order component is applied.

Next, the relationship between the induced voltage waveform and the voltage / current will be described with reference to FIGS.
13A and 13B are diagrams showing an outline of a waveform in a fixed coordinate system when the induced voltage waveform is an ideal sine wave. FIG. 13A is an induced voltage E1 [V], and FIG. 13B is an applied command voltage V1. [V] and (c) show the motor current I1 [A].

  FIG. 14 is a diagram showing an outline of a waveform in a fixed coordinate system when the induced voltage waveform is distorted. FIG. 14A is an induced voltage E1 [V], and FIG. 14B is an applied command voltage V1 [V. ] And (c) show the motor current I1 [A].

  FIG. 15 is a diagram showing an outline of a waveform in a rotating coordinate system based on the magnetic flux of the permanent magnet when the induced voltage waveform is an ideal sine wave, and (a) shows the induced voltage E [V]. , (B) shows the applied command voltage V [V], and (c) shows the motor current I [A].

  FIG. 16 is a diagram showing an outline of a waveform in a rotating coordinate system based on the magnetic flux of the permanent magnet when the induced voltage waveform is distorted. FIG. 16A is an induced voltage E [V], and FIG. Indicates the command voltage V [V] to be applied, and (c) indicates the motor current I [A].

The horizontal axes of FIGS. 13 to 16 are the electrical angle θ _ν [rad].
Further, φ in FIGS. 13 and 14 (a) and (b) is a phase difference between the command voltage and the induced voltage.
15 and 16, the subscripts d and q in the induced voltages Ed and Eq, the command voltages Vd and Vq, and the motor currents Id and Iq correspond to the d axis and the q axis, respectively.

  When the induced voltage waveform of the permanent magnet synchronous motor has an ideal sine wave shape, as shown in FIGS. 13B and 13C, the command voltage of the applied voltage command and the motor current have a sine wave shape, and rotation coordinates In the system, a constant value is obtained as shown in FIGS.

However, as shown in FIGS. 14 and 16, when the induced voltage waveform is distorted from a sinusoidal waveform (a), the motor current waveform is also distorted (c) due to these distortions, and the torque has a higher rotational speed. Ingredients are generated.
When the higher order component of the torque matches the resonance frequency caused by the fan or motor structure, vibration and noise are generated.
From the above, the motor control device of Comparative Example 1 shown in FIG. 12 has a configuration that is highly likely to generate vibration and noise.

≪Comparative example 2≫
Next, as Comparative Example 2, a method of adding the higher-order component 22A of the induced voltage to the fundamental wave applied voltage command 21B as it is will be described with reference to FIGS. In addition, illustration of the circuit which comprises the comparative example 2 is abbreviate | omitted.
FIG. 17 is a diagram showing a schematic waveform at a fixed coordinate when a higher-order component of the induced voltage is added to the applied voltage. (A) is the induced voltage [V], and (b) is the command voltage [V to be applied. ] And (c) show the motor current [A].
18A and 18B are diagrams showing schematic waveforms in the rotating coordinate system when a higher-order component of the induced voltage is added to the applied voltage. FIG. 18A shows the induced voltage [V], and FIG. 18B shows the command voltage to be applied [ V] and (c) show the motor current [A].
The horizontal axes of FIGS. 17 and 18 are the electrical angle θ _ν [rad].
Further, φ in FIGS. 17A and 17B is a phase difference between the command voltage and the induced voltage.
In FIGS. 17 and 18, the subscripts d and q in the induced voltages Ed and Eq, the command voltages Vd and Vq, and the motor currents Id and Iq correspond to the d axis and the q axis, respectively.

In Comparative Example 2, the higher-order component 22A is added to the fundamental wave applied voltage command 21B. For this reason, as shown in FIGS. 17B and 18B, a voltage to which the higher-order component 22A is applied is output to the applied voltage command 23A.
By applying the higher-order component of the voltage, the motor current is output as a motor current waveform in FIGS. 17C and 18C from which the higher-order component of the current (Id, Iq) is removed by applying the higher-order component of the voltage. Has been.
Thus, by applying a high-order component voltage, the high-order component contained in the current can be removed. Then, the higher order component of the torque should be reduced by removing the higher order component of the current.
However, the resonance noise of the fan and rotor did not disappear even if the fifth component of the phase current was reduced. Therefore, there are cases where noise cannot be eliminated by simply applying a high-order component of voltage.

  Further, as shown in FIGS. 17 (c) and 18 (c), even if the motor current has a clean sine waveform, the torque as the motor is related to the rotation, so the difference between the phase coordinates and the rotation coordinates is different. Therefore, the resonance sound of the fan and the rotor due to the torque is not always eliminated. Therefore, in the first embodiment, a method of more actively applying the fifth-order and seventh-order higher-order components is adopted.

(Second Embodiment)
A motor control device according to a second embodiment of the present invention will be described with reference to FIGS. 19 to 23 and FIG. 11.
In the second embodiment, when a fixed phase 60 degree switching method or a fixed phase 120 degree switching method, which will be described later, is employed as a modulation method for PWM control of a three-phase AC motor, ) A method for reducing the noise of resonance between the fan and motor of the next component (m is a positive integer) will be described.
In addition, fixed two-phase modulation is a method in which the potential of one phase is fixed and the other two phases are modulated at a predetermined electrical angle, including a fixed phase 60 degree switching method and a fixed phase 120 degree switching method described later. Shall be referred to as
First, the stationary phase 60 degree switching method and the stationary phase 120 degree switching method, which are control methods of the motor control device, will be described first. After that, a method for reducing the ninth-order component generated by this control method, and further a (6m + 3) -order component, and a specific circuit configuration will be described.

<Stationary phase 60 degree switching method>
Here, a PWM control modulation method in the motor control device will be described.
PWM control of a general three-phase AC motor is three-phase modulation (three-phase modulation method), but when the three-phase AC motor is Y-connected, two-phase is utilized by utilizing the fact that the phase voltage and the interphase voltage are different. There is a method of performing modulation (two-phase modulation method).
That is, by utilizing the fact that the motor current is determined not by the phase voltage but by the interphase voltage, while ensuring the interphase voltage, each phase voltage is always turned on at every predetermined period by switching on the inverter switching element. In this method, the switching loss of the inverter is reduced by sequentially fixing the electrical power level π / 3 (60 °, 60 °) to the higher power level or the lower power level.
In this method, as described above, one phase is fixed in potential in a predetermined section, and only the other two phases are modulated (PWM control). And this phase fixed in potential is repeated in order. Therefore, since only two phases are modulated at any time, this is called two-phase modulation.
Hereinafter, the two-phase modulation method is referred to as a fixed phase 60-degree switching method.

Next, the voltage waveform (voltage command) of the fixed phase 60 degree switching method is shown in FIG. 20, and this method will be described.
FIG. 20 is a diagram showing U-phase, V-phase, and W-phase voltage waveforms (voltage commands) in the fixed-phase 60-degree switching method, which is a two-phase modulation method.
FIG. 19 is a diagram showing voltage waveforms (voltage commands) of the U phase, the V phase, and the W phase in a general three-phase modulation method as a reference.
20 and 19, the horizontal axis represents the electrical angle [°], and the vertical axis represents the ratio of the voltage to the maximum voltage at each electrical angle, that is, the duty [%].

In FIG. 20, the W phase is constant at a lower limit voltage of 0% duty when the electrical angle is 0 degree (corresponding to [°]) to 60 degrees.
When the W phase is 0 to 60 degrees where the duty is 0%, the voltage difference and phase between the U phase and the V phase are the same as in the case of the three-phase modulation method shown in FIG. Take a voltage waveform that maintains the same relationship. That is, from 0 degrees to 60 degrees, the W-phase has a duty of 0%, so that the U-phase and the V-phase are slightly lower than the original voltage values.

  Further, from 60 degrees to 120 degrees, the U phase is constant at the upper limit voltage with a duty of 100%. In this section, the V phase and the W phase have a voltage waveform in which the voltage difference and phase with the U phase maintain the same relationship as in the case of the three-phase modulation shown in FIG. Take a slightly higher value. Note that at 60 degrees when the U phase is 100% duty at once, the voltages of the V phase and the W phase suddenly rise.

  Also, from 120 degrees to 180 degrees, the V phase is constant at the lower limit voltage with a duty of 0%. In this section, the W phase and the U phase have a voltage waveform that maintains the same relationship as the case of the three-phase modulation method shown in FIG. A slightly lower value. It should be noted that at 120 degrees when the V phase becomes a duty of 0% at once, the voltages of the W phase and the U phase suddenly drop.

Control is repeated so that the operation waveforms of the U phase, V phase, and W phase are as described above.
As shown in FIG. 20, the U-phase, V-phase, and W-phase interphase voltages have different waveforms from the sine wave, but the U-phase-V phase line voltage, V-phase-W-phase line voltage, W Since the phase-U phase line voltage has a sine waveform, the motor 13 (FIG. 23) and the fan 14 (FIG. 23) driven by the three-phase line voltage are shown in FIG. The operation is the same as in the case of the three-phase modulation method.
However, since the W phase is constant from 0 to 60 degrees, the U phase is from 60 to 120 degrees, and the V phase is from 120 to 180 degrees, the number of PWM control operations by the inverter 15 is reduced. it can. Therefore, the power consumption of the inverter 15 is reduced.

In addition, in 0 to 360 degrees and all the sections in which it is repeated, any of the U phase, V phase, and W phase is fixed, and the remaining two phases are modulated. Therefore, as described above, the two-phase modulation is performed.
Further, “Semiconductor power conversion circuit” as Non-Patent Document 3, pages 110, 111, 125, etc., published by the Institute of Electrical Engineers of Japan in March 1987, show the same or similar technology.

<Stationary phase 120 degree switching method: Part 1>
Next, the stationary phase 120 degree switching method in which the fixed section per phase is longer than the stationary phase 60 degree switching method will be described.
The stationary phase 120 degree switching method includes an upper stationary phase 120 degree switching method for fixing the stationary phase to a high DC voltage potential, and a lower stationary phase 120 degree switching for fixing the stationary phase to a low DC voltage potential. There are two types of methods. Next, the upper stationary phase 120 degree switching method and the lower stationary phase 120 degree switching method will be described in order.

<< Upper stationary phase 120 degree switching method >>
FIG. 21 is a diagram showing U-phase, V-phase, and W-phase voltage waveforms (voltage commands) in the upper stationary phase 120-degree switching method that is a two-phase modulation method. The horizontal axis represents the electrical angle [°], and the vertical axis represents the voltage duty [%].
In FIG. 21, the U-phase is constant from 30 degrees (corresponding to [°]) to 150 degrees at the upper limit voltage of 100% duty.
The W phase is constant from 150 degrees to 270 degrees with the upper limit voltage of 100% duty.
The V phase is constant from the upper limit voltage of 100% duty from 270 degrees to (390) degrees.

As described above, each of the U phase, the V phase, and the W phase is fixed at a high power supply level for each phase at an electrical angle of 2π / 3 (120 degrees).
Further, in the section where one phase of each of the U phase, the V phase, and the W phase is fixed, the other phases indicate the voltage difference and phase with the above phases in the case of the three-phase modulation method shown in FIG. Control to take a voltage waveform that maintains the same relationship as.
Therefore, the U-phase, V-phase, and W-phase can be Y-connected, and the three-phase AC motor can be driven with the respective line voltages.

<< Lower stationary phase 120 degree switching method >>
FIG. 22 is a diagram illustrating voltage waveforms (voltage commands) of the U phase, the V phase, and the W phase in the lower fixed phase 120-degree switching method that is a two-phase modulation method. The horizontal axis represents the electrical angle [°], and the vertical axis represents the voltage duty [%].
In FIG. 22, the V-phase is constant from 90 degrees (corresponding to [°]) to 210 degrees at the lower limit voltage of 0% duty.
Further, the U phase is constant at a lower limit voltage of 0% duty from 210 degrees to 330 degrees.
Further, the W phase is constant from 330 degrees to (450) degrees and from (-30) degrees to 90 degrees with a lower limit voltage of 0% duty.

As described above, each of the U phase, the V phase, and the W phase is fixed to the low potential power supply level for each phase during an electrical angle of 2π / 3 (120 degrees).
Further, in the section where one phase of each of the U phase, the V phase, and the W phase is fixed, the other phases indicate the voltage difference and phase with the above phases in the case of the three-phase modulation method shown in FIG. Take a voltage waveform that maintains the same relationship as.
Therefore, it is possible to drive the three-phase motor with each line voltage with the U-phase, V-phase, and W-phase as Y connections.

<Stationary phase 120 degree switching method: Part 2>
As described above, both the upper stationary phase 120 degree switching method and the lower stationary phase 120 degree switching method are sequentially fixed to the high power level or the low power level for each phase by an electrical angle of 2π / 3 (120 degrees, 120 °). Therefore, the switching loss of the inverter can be reduced.
When the amplitude of the phase voltage becomes lower than a predetermined voltage value, if the situation shown in FIG. 21 or FIG. 22 is not appropriate, the two-phase modulation method is stopped and the motor is controlled by the three-phase modulation method. There is also a method of applying a phase voltage.
Patent Document 2 discloses the same or similar technique as described above.

[Reduction of 9th order component]
In the two-phase modulation type fixed phase 60 ° switching method and the fixed phase 120 ° switching method, a ninth-order component is generated.
That is, when a three-phase motor is driven with a sine wave, even though the three-phase even-order component does not generally occur, the lower stationary phase 120 degree switching method shown in FIG. Even order occurs. The even-order 8th-order and 10th-order components (components of each phase) generate 9th-order components (components of the rotating coordinate system), which can cause noise of the 9th-order components.
Therefore, in order to reduce the 9th-order component (component of the rotating coordinate system) of the 3-phase motor, it may be necessary to reduce the 8th-order and 10th-order components (components of each phase) of the three phases.
A ninth-order component is generated by the action of the sum of the fundamental wave (first-order component) and the eighth-order component. Further, a ninth-order component is generated by the action of the difference between the fundamental wave (first-order component) and the tenth-order component.

FIG. 11 is a diagram illustrating an example of a motor waveform (voltage, current) and a waveform obtained by performing FFT analysis of the motor current when the motor is operated by the lower stationary phase 120-degree switching method. ) Is a waveform of the motor terminal voltage, (b) is a waveform of the motor current, and (c) is a waveform obtained by performing FFT analysis of the motor current.
In addition, the horizontal axis of FIGS. 11A and 11B is the transition of time, and the vertical axis is the voltage value and the current value, respectively. Further, the horizontal axis of 11 (c) is the frequency, and the vertical axis is the ratio of the current component.
Looking at the FFT in FIG. 11 (c), the eighth-order component and the tenth-order component are relatively large.
Next, a method for reducing the ninth order sound by reducing the even order (8th order and 10th order) generated in the above-described stationary phase 60 degree switching method will be described.
In addition, the order having the sound reduction effect by the selection of this modulation method is generally (6m + 3) th order (m is a positive integer) such as 15th order, 21st order,.

<Circuit configuration>
Next, the configuration of the motor control device that reduces the (6m + 3) th order (m is a positive integer) high-order component in the two-phase modulation type fixed phase 60 degree switching method and the fixed phase 120 degree switching method will be described. .
FIG. 23 is a diagram showing the internal configuration of the motor control device 11 according to the second embodiment of the present invention and the relationship among the motor control device 11, the DC power source 12, the motor (three-phase motor) 13, and the fan 14. is there.
In FIG. 23, the configuration of the control device 171 of the motor control device 11 is characterized as the second embodiment.
The DC power supply 12, the motor 13, the fan 14, the inverter 15, and the DC bus current detection circuit 16 are the same as those in the first embodiment shown in FIG.

The control device 19 includes a vector control unit 21, a PWM pulse generation unit 24, and a modulation method selection unit 25.
The vector control unit 21 acquires the phase current information 16 A from the DC bus current detection circuit 16, calculates the motor rotation speed / phase information (rotation information) 21 A, and outputs it to the modulation method selection unit 25. The vector control unit 21 also outputs a fundamental wave applied voltage command 21B to the PWM pulse generation unit 24.
Based on the motor rotation speed / phase information (rotation information) 21A, the modulation method selection unit 25, when the resonance frequency component exceeds a predetermined range that is a noise limit, 60 degrees (or 60 degrees) of the fixed phase of the two-phase modulation method (or 120 degrees) The switching method or the three-phase modulation method is selected, and the modulation method selection signal 12A is output to the PWM pulse generator 24.
The PWM pulse generator 24 generates PWM pulse information 19A for controlling the pulse width of the inverter 15 based on the fundamental wave applied voltage command 21B and the modulation method selection signal 25A.
With the above configuration, in the two-phase modulation method of the fixed phase 60 degree switching method and the stationary phase 120 degree switching method, the control device 19 uses the control device 19 to add the (6m + 2) -order and (6m + 4) -order higher-order components. (6m + 3) -order higher-order component is reduced by applying to the basic component.

<Effects of Second Embodiment>
According to the second embodiment, the three-phase modulation or the two-phase modulation of the fixed-phase 60-degree switching method is used, and while reducing power consumption, the motor rotation speed is (6m + 3) order (m is a positive integer). Resonance noise of the fan and rotor of the frequency can be reduced.

(Third embodiment)
Next, a motor control device according to a third embodiment of the present invention will be described with reference to FIG.
The third embodiment includes the higher-order component generation unit 22 and the voltage addition unit 23 of the first embodiment and the modulation scheme selection unit 25 of the second embodiment.

<Configuration of Motor Control Device According to Third Embodiment>
FIG. 24 is a diagram illustrating an internal configuration of the motor control device 11 according to the third embodiment of the present invention, and a relationship among the motor control device 11, the DC power source 12, the three-phase motor 13, and the fan 14.
In FIG. 24, the configuration of the control device 20 of the motor control device 11 is characterized as the third embodiment.
The DC power supply 12, the motor 13, the fan 14, the inverter 15, and the DC bus current detection circuit 16 are the same as those in the first embodiment shown in FIG.

The control device 20 includes a vector control unit 21, a PWM pulse generation unit 24, a high-order component generation unit 22, a voltage addition unit 23, and a modulation scheme selection unit 25.
The vector control unit 21 acquires the phase current information 16A from the DC bus current detection circuit 16, calculates the motor rotation speed / phase information 21A, and outputs it to the high-order component generation unit 22 and the modulation method selection unit 25. . The vector control unit 21 also outputs a fundamental wave applied voltage command 21B to the voltage adding unit 23.
The high-order component generator 22 generates a high-order component 22A based on the motor rotation speed / phase information 21A and outputs the high-order component 22A to the voltage adder 23.
The voltage adding unit 23 adds the fundamental wave applied voltage command 21B and the higher-order component 22A and outputs the applied voltage command 23A.

Based on the motor rotation speed / phase information 21A, the modulation method selection unit 25 selects either the fixed phase 60 degree (or 120 degree) switching method of the two-phase modulation method or the three-phase modulation method, and sends the modulation method selection signal 25A. Output to the PWM pulse generator 24.
The PWM pulse generator 24 generates PWM pulse information 20A based on the applied voltage command 23A and the modulation method selection signal 25A.
With the above configuration, a high-order component of 6 m order is applied with a predetermined phase and amplitude, and the resonance noise of the fan 14 and the rotor (13) having a frequency is reduced. In addition, the resonance sound of the fan 14 and the rotor (13) having a frequency of 3m order (m is a positive integer) of the motor rotation speed can be reduced by using the three-phase modulation or the two-phase modulation of the fixed phase 60 degree switching method. Can do.

<Measurement results of noise reduction of the third embodiment>
Next, measurement results of noise reduction of the third embodiment will be described with reference to FIGS.

<Measurement waveform>
FIG. 25 is a diagram showing waveforms of motor terminal voltage and motor current when FFT is applied in the case of applying a fifth-order component and switching a fixed phase 60 ° of two-phase modulation at 510 min ⁻¹ . (A) is a waveform of the motor terminal voltage, (b) is a waveform of the motor current, and (c) is a waveform obtained by performing FFT analysis of the motor current.
In addition, the horizontal axis of FIGS. 25A and 25B is a transition of time, and the vertical axis is a voltage value and a current value, respectively. In FIG. 25C, the horizontal axis represents frequency, and the vertical axis represents the ratio of current components.
Note that the application of the fifth-order component at 510 min ⁻¹ is (Formula 1) in which the phase θ is 62 degrees and the ratio G ₅ to the induced voltage fundamental wave amplitude is 3%.

《Noise spectrum》
FIG. 26 is a diagram showing the noise spectrum of the fan under the measurement conditions of the motor of FIG.
When the noise spectrum of FIG. 26 is compared with the noise spectrum of FIG. 6, sudden noises having frequencies of 200 Hz and 316 Hz seen in FIG. 6 are reduced.

<Effect of the third embodiment>
Therefore, the third embodiment has an effect of reducing various resonance sounds of the fan and the rotor.

(Fourth embodiment)
Next, a mode in which the motor control device 11 described in the first to third embodiments is applied to the fan motor control device 108 of the outdoor unit 101 of the air conditioner 100 will be described as a fourth embodiment.
FIG. 27 is a diagram illustrating a configuration example of an air conditioner 100 according to the fourth embodiment of the present invention.
In FIG. 27, the air conditioner 100 includes an outdoor unit 101 that exchanges heat with the outside air, an indoor unit 102 that exchanges heat with the room, and a pipe 103 that connects the two.
The outdoor unit 101 includes a compressor 104 that compresses a refrigerant, a heat exchanger 105 that exchanges heat with the outside air, an outdoor fan 106 that blows air to the heat exchanger 105, an outdoor fan motor 107 that rotates the outdoor fan 106, And a motor control device 108 for driving the outdoor fan motor 107. Note that the motor control device 108 of the first to third embodiments is applied to the motor control device 108.

The indoor unit 102 includes a heat exchanger 109 that exchanges heat with the room, and a blower 110 that blows air into the room.
In the fourth embodiment, as described above, the motor control device 11 of the first to third embodiments is applied to the air conditioner 100. That is, in the control device (17, 19, 20) for controlling the inverter 15, a high-order component is applied or a modulation method is selected, whereby the fan 14 and rotor (motor) 13) Resonance noise is reduced.

<Effects of Fourth Embodiment>
According to the fourth embodiment, it is possible to reduce the sound without using the vibration isolation rubber of the rotor part of the outdoor fan motor 107 or the vibration isolation rubber of the fan part, so that the quiet air conditioner 100 can be manufactured at low cost. Become.

(Other embodiments)
As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, this invention is not limited to these embodiment and its deformation | transformation, There exists a design change etc. of the range which does not deviate from the summary of this invention. Well, here are some examples:

《Realization of each configuration and function》
Each configuration, function, processing unit, processing means, and the like of the present embodiment may be realized by hardware by designing a part or all of them with an integrated circuit, for example. Moreover, you may implement | achieve by the software which can change a program. Also, hardware and software may be mixed.
Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

<< Combination and replacement of each configuration and function >>
Part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

《Load, noise source》
In addition, for the sake of clarity, the description has been given mainly for the case where the fan is driven as a load. However, the present invention is effective in reducing the sound caused by the structural resonance frequency, and the load is limited to the fan. Not what you want.

<Acquisition of phase current information>
The acquisition of the phase current information by the DC bus current detection circuit 16 can be performed by using a general method such as the method disclosed in Japanese Patent Application Laid-Open No. 2004-48886 as Patent Document 3, and specifies the detection method. is not.

《Vector control》
The vector control unit 21 can be realized by using general vector control such as the methods proposed in Non-Patent Document 1 and Non-Patent Document 2, and does not specify a control method.

<< Switching element, semiconductor element >>
The IGBT is used as the switching element of the power conversion main circuit 51. However, a switching element of another semiconductor element may be used, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). Further, a semiconductor element using SiC (Silicon Carbide, silicon carbide) or GaN (Gallium Nitride, gallium nitride) as the composition of the element may be used.

《Change of G and φ of high-order component application type》
In the high-order component application formula, G (ratio of higher-order wave amplitude to induced voltage fundamental wave amplitude) and φ (phase difference between fundamental wave component and higher-order component) were initially explained using the set values. However, based on the information of the DC bus current detection circuit 16, there is also a method in which the vector control unit 21 changes G and φ appropriately according to the situation and performs optimal control.

《Gate driver》
The gate driver 52 in FIG. 1 has a main function to increase the signal drive capability of the PWM pulse generation unit 24. Therefore, the gate driver 52 has sufficient drive capability at the output unit of the PWM pulse generation unit 24, or the gate driver. If the function 52 is built in the PWM pulse generator 24, the inverter 15 does not have to include the gate driver 52.

DESCRIPTION OF SYMBOLS 11, 108 Motor control device 12 DC power supply 13 Motor, 3 phase motor, 3 phase AC synchronous motor 14 Load, fan 15 Inverter, power conversion circuit 16 DC bus current detection circuit 17, 18, 19, 20 Control device 21 Vector control unit 22 Higher Order Component Generation Unit 23 Voltage Addition Unit 24 PWM Pulse Generation Unit 25 Modulation Method Selection Unit 51 Power Conversion Main Circuit 52 Gate Driver 100 Air Conditioner 101 Outdoor Unit 102 Indoor Unit 103 Piping 104 Compressor 105 Heat Exchanger (Outdoor Heat exchanger)
106 outdoor fan 107 outdoor fan motor 109 heat exchanger (indoor heat exchanger)
110 Blower

Claims (6)

An inverter that is connected to a DC power source, converts DC power of the DC power source into AC power of variable voltage and variable frequency, and drives and controls a three-phase motor;
A vector control unit for calculating a voltage applied to the three-phase motor that rotationally drives a load;
A high-order component generation unit that calculates a high-order component of the fundamental wave of the applied voltage of the vector control unit;
A voltage addition unit that adds the higher-order component calculated by the higher-order component generation unit to the applied voltage calculated by the vector control unit;
A PWM pulse generation unit having a plurality of modulation methods including a fixed two-phase modulation method, and performing pulse width control of the inverter based on a signal of the voltage addition unit;
A modulation method selection unit that selects the plurality of modulation methods included in the PWM pulse generation unit;
With
Based on the rotation information of the three-phase motor obtained by the vector control unit, when a resonance frequency component exceeds a predetermined range, the modulation method selection unit selects one of the plurality of modulation methods, The PWM pulse generation unit controls the inverter with the selected modulation method to reduce resonance sound that resonates at a frequency of (6m + 3) times (m is a positive integer) the rotation frequency of the three-phase motor. A motor control device. An inverter that is connected to a DC power source, converts DC power of the DC power source into AC power of variable voltage and variable frequency, and drives and controls a three-phase motor;
A vector control unit for calculating a voltage applied to the three-phase motor that rotationally drives a load;
A high-order component generation unit that calculates a high-order component of the fundamental wave of the applied voltage of the vector control unit;
A voltage addition unit that adds the higher-order component calculated by the higher-order component generation unit to the applied voltage calculated by the vector control unit;
A PWM pulse generation unit having a plurality of modulation methods including a fixed two-phase modulation method, and performing pulse width control of the inverter based on a signal of the voltage addition unit;
A modulation method selection unit that selects the plurality of modulation methods included in the PWM pulse generation unit;
With
The high-order component generation unit generates (6m-1) -order and (6m + 1) -order high-order components or any one of the fundamental components of the three-phase applied voltage, and applies them to the voltage addition unit. A function of reducing resonance sound that resonates at a frequency 6 m times (m is a positive integer) the rotational frequency of the three-phase motor;
Based on the rotation information of the three-phase motor obtained by the vector control unit, when the resonance frequency component exceeds a predetermined range, the modulation method selection unit selects one of the modulation methods and the selected The PWM pulse generator controls the inverter with the modulation method, and reduces the resonance sound that resonates at a frequency of (6m + 3) times (m is a positive integer) the rotational frequency of the three-phase motor;
And a motor control device characterized by comprising: The stationary 2-phase modulation method, the stationary phase 60 degrees switching system or on the stationary phase 120 degrees switching mode or motor according to claim 1 or claim 2, characterized in that the lower stationary phase 120 degrees switching scheme, Control device. The motor control device according to claim 1 or claim 2, characterized in that 3-phase modulation method is provided in the plurality of modulation schemes. The motor control device according to any one of claims 1 to 4 , wherein the load of the three-phase motor is a fan. An air conditioner equipped with the motor control device according to any one of claims 1 to 5 .