JP6917201B2 - Power converter and air conditioner - Google Patents

Description

The present invention relates to a power converter and an air conditioner.

There are various types of air conditioner compressors such as scroll compressors, reciprocating compressors, and rotary compressors, and the load torque of the motor built into these compressors generates pulsations synchronized with the rotation cycle. do. This load torque pulsation causes a problem that the rotation speed fluctuates and vibration is generated from the compressor. As a method for solving this problem, torque control is known in which the output torque of the motor is adjusted according to the load torque pulsation to keep the rotation speed constant. As an example, the following Patent Document 1 states, "When a load device to be rotationally driven by an AC synchronous motor generates a periodic disturbance, the input power is reduced while suppressing the periodic disturbance. By providing a limiter 227 that limits the current component that corrects the pulsating component in the torque control 22 that extracts the pulsating component of the torque generated by the load device and compensates for it. It can be achieved "(see abstract).

Japanese Unexamined Patent Publication No. 2006-180605

When torque control is performed, the rotation speed of the motor built in the compressor can be kept substantially constant, but there is a problem that the power consumption of the motor increases. Further, the vibration of the compressor fluctuates under the influence of the natural frequency of the compressor, the rotation speed of the motor, the mounting state of the refrigerant pipe, and the like. Therefore, it is desirable that the torque control can be strengthened only when the vibration of the compressor is large. In order to realize this, it is conceivable to investigate the conditions under which the vibration of the compressor increases for each air conditioner and add the results to the conditions for torque control in the inverter controller. However, in order to investigate the condition that the vibration of the compressor, that is, the pulsation of the motor becomes large, a lot of man-hours are required, which leads to an increase in cost.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power converter and an air conditioner capable of realizing appropriate torque control of a motor while suppressing an increase in cost.

In order to solve the above problems, in the power converter of the present invention, an inverter circuit that converts the supplied DC voltage into an output voltage that is an AC voltage and applies it to the motor, and a controller that controls the inverter circuit. The controller has a pulsation suppression unit that suppresses pulsation generated at the rotational speed of the motor, and a pulsation suppression control unit that sets an on / off state of the pulsation suppression unit according to the state of the motor. , have a, the pulsation suppression control section, when the fluctuation width of the rotational speed is a predetermined rotational speed determination value or more, the axis error is the difference between the magnetic pole position detected magnetic pole position on the control of the motor When the fluctuation range of is equal to or greater than the predetermined axial error pulsation determination value, or when the fluctuation width of the pulsation component of the torque generated by the motor is equal to or greater than the predetermined torque pulsation determination value, the pulsation suppression unit is turned on. It is characterized by setting.

According to the present invention, appropriate torque control can be realized while suppressing cost increase.

It is a block diagram of the motor drive system according to 1st Embodiment of this invention. It is a block diagram which shows the algorithm of the controller in 1st Embodiment. It is a waveform diagram of the U-phase voltage modulation factor before modulation, the modulation signal, and the U-phase voltage modulation factor after modulation. It is a waveform diagram of a PWM signal and a carrier signal. It is a block diagram which shows the control algorithm of the torque control determination part. It is a waveform diagram of (a) the estimated value of the torque pulsation component, (b) the maximum value and the minimum value thereof, and (c) the reset signal. It is a waveform diagram of (a) mechanical frequency, (b) torque control flag, and (c) pulsation avoidance flag. It is a block diagram which shows the algorithm of the controller in 2nd Embodiment. It is a block diagram which shows the algorithm of the torque pulsation determination part in 2nd Embodiment. It is a block diagram which shows the algorithm of the pulsation avoidance control part in 2nd Embodiment. It is a refrigerating cycle system diagram of the air conditioner according to 3rd Embodiment.

[First Embodiment]
<Hardware configuration of the first embodiment>
Hereinafter, the details of the motor drive system S1 according to the first embodiment of the present invention will be described.
FIG. 1 is a block diagram of a motor drive system S1 according to the first embodiment of the present invention. In FIG. 1, the motor drive system S1 includes a converter circuit 2 that converts an AC voltage from an AC voltage source 1 into a DC voltage, an inverter device 3 (power conversion device), and a permanent magnet synchronous motor 4 (hereinafter referred to as a motor 4). ) And. The motor 4 includes a rotor (not shown) in which a permanent magnet is embedded and a stator (not shown) having windings.

The converter circuit 2 includes a three-phase diode bridge 5, a DC reactor 6, and a smoothing capacitor 7. When a three-phase AC voltage is supplied from the AC voltage source 1 to the three-phase diode bridge 5, a full-wave rectified voltage is output from the three-phase diode bridge 5. The output of the three-phase diode bridge 5 has a P side and an N side, and the P side is connected to the DC reactor 6. A smoothing capacitor 7 is connected between the output of the DC reactor 6 and the N-side output of the three-phase diode bridge 5. Then, the voltage between the terminals of the smoothing capacitor 7 is output from the converter circuit 2 as a DC voltage.

The DC voltage output from the converter circuit 2 is input to the inverter device 3. The inverter device 3 includes a DC voltage detection circuit 8, an IPM (Intelligent Power Module) 9 having an inverter function, a U-phase motor current detection circuit 10, a V-phase motor current detection circuit 11, and a controller 12. And a gate drive circuit 13.

The DC voltage supplied from the converter circuit 2 is input to the IPM9 (inverter). The IPM9 has six IGBTs and an FWD (Free Wheeling Diode) connected in parallel to each IGBT (both are unsigned). Then, the IPM 9 converts the DC voltage into a three-phase AC voltage by turning each IGBT on / off by the gate tribe signal 18 supplied from the gate drive circuit 13. The three-phase AC voltage becomes the output of the inverter device 3. Further, the DC voltage detection circuit 8 measures the DC voltage input to the inverter device 3 and supplies the measurement result as the DC voltage detection signal 14 to the controller 12.

The three-phase AC voltage output by the inverter device 3 is applied to the winding of the motor 4. Further, among the three-phase currents flowing through the motor 4, the U-phase and V-phase current detection circuits 10 and 11 supply the U-phase motor current detection signal 15 and the V-phase motor current detection signal 16 to the controller 12, respectively. .. The controller 12 calculates the duty ratio for turning on / off the IGBT in the IPM 9 based on the DC voltage detection signal 14, the U-phase motor current detection signal 15, and the V-phase motor current detection signal 16. The PWM signal 17 having the duty ratio is output. The PWM signal 17 is converted into a gate tribe signal 18 having a voltage sufficient to turn on / off the IGBT in the gate drive circuit 13.

The controller 12 includes hardware as a general computer such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and the ROM is a control executed by the CPU. Programs, various data, etc. are stored.

<Algorithm configuration of the first embodiment>
FIG. 2 is a block diagram showing an algorithm of the controller 12, and shows a function realized by a control program or the like as a block.
In FIG. 2, the U-phase motor current detection signal 15 and the V-phase motor current detection signal 16 are input to the A / D converter 19. Then, the A / D converter 19 multiplies the U-phase motor current detection signal 15 and the V-phase motor current detection signal 16 by a predetermined gain, respectively, _{and obtains the results of the U-phase current detection values I U} and the V-phase current detection values. Output as _IV.

A U-phase current detection value I _U , a V-phase current detection value _IV, and a d-axis phase θ _dc (details will be described later) are input to the dq converter 20. Then, the dq converter 20 outputs the d-axis current detection value I _dc and the q-axis current detection value I _qc based on the following [Equation 1].

Here, it is assumed that the coordinate system rotates by the electric angle of the motor 4 (the value obtained by multiplying the mechanical angle by the number of pole pairs of the motor 4). In this coordinate system, the direction of the magnetic flux generated by the permanent magnet is the d-axis, and the axis orthogonal to the d-axis is the q-axis. The coordinate system having the d-axis and the q-axis is called a "dq-axis coordinate system". The d-axis current detection value I _dc and the q-axis current detection value I _qc described above are values on the dq-axis coordinate system.

Further, the axis error calculation unit 21 includes a d-axis current detection value I _dc , a q-axis current detection value I _qc , a d-axis voltage command value V _d ^* , a q-axis voltage command value V _q ^*, and an inverter frequency. ω ₁ and are entered. Then, the axis error calculation unit 21 calculates and outputs the _{axis error Δθ c based on the following [Equation 2].} In [Equation 2], R is the motor winding resistance value, L _d is the motor d-axis inductance, and L _q is the motor q-axis inductance.

Here, the control magnetic pole position of the motor 4 is “tan ^-1 {V _d ^* / V _q ^* }”, and the detected magnetic pole position is “tan ^-1 {R × I _dc −ω ₁ × L _q”. × I _qc ) / {R × I _qc + ω ₁ × L _q × I _dc )} ”. Then, the axis error Δθ _c shown in [Equation 2] becomes an error between the controlled magnetic pole position of the motor 4 and the detected magnetic pole position.

The PLL control unit 22 performs proportional integral control with _{the axis error Δθ c} as an input, and calculates the _{inverter frequency ω 1.} The d-axis phase update unit 23 adds _{the value Δθ dc} obtained by dividing the _{inverter frequency ω 1} by the calculation cycle to the previous output value (one calculation cycle before) _{of the d-axis phase θ dc.} Then, the d-axis phase update unit 23 outputs the value after addition as the current value of the _{d-axis phase θ dc.} The speed control unit 24 calculates the deviation Δω (not shown) between the inverter frequency command value ω ₁ ^* (frequency command value) and the inverter frequency ω ₁ , performs proportional integration control based on the deviation Δω, and performs the q-axis current. Calculate the command value I _q ^*.

The current control unit 25 calculates the deviation ΔI _q (not shown) between the q-axis current command value I _q ^* and the q-axis current detection value I _{qc , performs proportional integration control with the deviation ΔI q} as an input, and q. Calculate the shaft current command correction amount (not shown). Further, the current control unit 25 adds the q-axis current command value I _q ^* , the q-axis current command correction amount, and the torque control output current command value I _qsin ^* (details will be described later) to the second value. Output as q-axis current command value I _q ^**. Furthermore, the current controller 25 performs proportional integral control deviation [Delta] I _d (not shown) to the input of the d-axis current command value I _d ^* and the d-axis current detection value I _dc, the result of the second Output as d-axis current command value I _d ^**.

The V _d V _q calculation unit 26 inputs the inverter frequency command value ω ₁ ^* , the second q-axis current command value I _q ^** , and the second d-axis current command value I _d ^** , and describes the following. In [Equation 3], the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* are calculated. In [Equation 3], _Ke is the induced voltage constant of the motor 4.

The AVR (Automatic Voltage Regulator, voltage correction) calculation unit 27 _{inputs the d-axis voltage command value V d} ^* and the q-axis voltage command value V _q ^*, and calculates the motor voltage phase δθ based on [Equation 4]. do.

Further, the AVR calculation unit 27 calculates the voltage command peak value V ₁ based on [Equation 5].

_{Further, the AVR calculation unit 27 calculates the DC voltage detection value V dc} , which is a value obtained by multiplying the DC voltage detection signal 14 by a predetermined gain (referred to as the DC voltage detection circuit gain), and based on [Equation 6], calculates the DC voltage detection value V dc. _{Calculate the} motor voltage modulation factor K hV1 (not shown).

Further, the AVR calculation unit 27 calculates and outputs the _{d-axis voltage modulation factor K hVd} and the q-axis voltage modulation factor K _{hVq based on [Equation 7].}

Further, the dq inverse conversion unit 28 takes the d-axis voltage modulation factor K _hVd , the q-axis voltage modulation factor K _hVq, and the d-axis phase θ _{dc as inputs, and based on [Equation} 8], the U-phase voltage modulation factor K hVu , V-phase voltage modulation factor K _hVv , and W-phase voltage modulation factor K _hVw are output.

Further, the modulation processing unit 29 modulates the U, V, W phase voltage modulation factors K _hVu , K _hVv , and K _{hV w} with a modulation signal MD that approximates a triangular wave, and the modulated U, V, W phase voltage modulation factor K. _{Outputs hVu} ', K _hVv ', and K _hVw '. That is, the U, V, W phase voltage modulation rates K _hVu ', K _hVv ', and K _hVw ' after modulation are shown in [Equation 9].

FIG. 3 is a waveform diagram of the U-phase voltage modulation factor K _hVu before modulation, the modulation signal MD, and the U-phase voltage modulation factor K _hVu'after modulation. The corresponding V-phase signal is delayed by 120 ° with respect to the U-phase, and the corresponding W-phase signal is delayed by 240 ° with respect to the U-phase.
By performing the above-mentioned modulation processing in the modulation processing unit 29, _{the utilization rate of the DC voltage detection value V dc} is improved, and the output voltage of the inverter device is improved by up to 15% as compared with the case where the motor 4 is driven by a sine wave. do. The modulation processing unit 29 also executes upper and lower limit processing. That is, the upper limit of the output value is limited to 1, and the lower limit is limited to -1.

Returning to FIG. 2, the PWM signal conversion unit 30 _{compares the magnitude relationship between the U, V, W phase voltage modulation factors K hVu} ', K _hVv ', K _hVw'and the carrier signal, and outputs the PWM signal 17. do. Here, the PWM signal 17 is a U-phase P-side PWM signal, a U-phase N-side PWM signal, a V-phase P-side PWM signal, a V-phase N-side PWM signal, a W-phase P-side PWM signal, and a W-phase N-side PWM signal. It has 6 signals of.

FIG. 4 is a waveform diagram of these PWM signals and carrier signal CR. As shown in the figure, the carrier signal CR is a triangular wave having a constant period. Further, the P-side PWM signal and the N-side PWM signal of each phase are signals in which on / off is inverted.

Returning to FIG. 2, the torque pulsation estimation unit 31 outputs the torque pulsation component estimated value ΔT _{mc with the axis error Δθ c as an input.} As _{a method for calculating ΔT mc} , for example, the method described in paragraphs 0017 to 0028 of Patent Document 1 (Japanese Unexamined Patent Publication No. 2006-180605) can be applied. The torque control determination unit 32 outputs the torque control flag FLG _trq (details will be described later) _{based on the axis error Δθ c} , the inverter frequency ω _1, and the torque pulsation component estimated value ΔT _mc. Further, the torque control unit 33 outputs the above-mentioned torque control output current command value I _qsin ^* _{based on the torque pulsation component estimated value ΔT mc} and the torque control flag FLG _trq .

FIG. 5 is a block diagram showing a control algorithm of the torque control determination unit 32.
In FIG. 5, the peak holding unit 40 holds the axial error Δθ _c , the torque pulsation component estimated value ΔT _mc , and the maximum and minimum values of the inverter frequency ω _{1, respectively.}
Here, the pulsating cycles of _{Δθ c} , ΔT _mc, and ω _{1 are examined.} Assuming that the motor 4 (see FIG. 1) drives a load such as a reciprocating compression mechanism or a rotary compression mechanism, the pulsation of the load torque is the main cause of the vibration of the motor 4. Here, _{the pulsations of Δθ c} , ΔT _mc and ω ₁ are synchronized with the mechanical frequency ω _m (not shown) of the motor 4. Then, assuming that the number of pole pairs of the permanent magnets embedded in the motor 4 is Pt, the mechanical frequency ω _m is “ω _m = ω ₁ / Pt”. The cycle determination processing unit 48 outputs a reset signal to the peak holding unit 40 _{based on the inverter frequency ω 1} and the pole logarithm Pt, that is, _{every “1 / ω m”.} Upon receiving the reset signal, the peak holding unit 40 resets the holding maximum and minimum values of _{Δθ c} , ΔT _mc, and ω _1.

The subtractors 42, 44, and 46 output each of these vibration amplitudes by subtracting the minimum values from the maximum values of _{Δθ c} , ΔT _mc, and ω _{1 output from the peak holding unit 40.} These vibration amplitudes are called axis error pulsating vibration amplitude Aθ _c , torque pulsating vibration amplitude AT _mc , and inverter frequency pulsating vibration amplitude Aω ₁ .

_{FIG. 6A is} a waveform diagram of the torque pulsation component estimated value ΔT mc. FIG. 6B is a waveform diagram of the maximum value and the minimum value of the torque pulsation component estimated value ΔT _{mc output from the peak holding unit 40.} The difference between the maximum value and the minimum value is the vibration amplitude AT _mc . Further, FIG. 6C is a waveform diagram of a reset signal output from the cycle determination processing unit 48.

Returning to FIG. 5, the comparators 52, 54, and 56 compare the vibration amplitudes Aθ _c , AT _mc , and Aω ₁ with the corresponding determination values, respectively. These judgment values are called the axis error pulsation judgment value B θ _c , the torque pulsation judgment value BT _mc , and the inverter frequency pulsation judgment value B ω ₁ . The shaft error pulsation determination value B θ _c is preferably about 10 deg, and the torque pulsation determination value BT _mc is preferably about 20% of the rated torque of the motor 4. Further, the inverter frequency pulsation determination value Bω ₁ is preferably set to about 4 rps (revolutions per second).

_{That is, if the vibration amplitudes Aθ c} , AT _mc , and Aω ₁ are equal to or greater than the corresponding determination values Bθ _c , BT _mc , and Bω ₁ , the comparators 52, 54, and 56 output a “1” signal, and other than that. In the case of, a "0" signal is output. The OR circuit 58 outputs the logical sum of the output signals of the comparators 52, 54, and 56 as the pulsation avoidance flag FLG _pulse . That is, if any of the vibration amplitudes Aθ _c , AT _mc , and Aω ₁ is equal to or greater than the corresponding determination values Bθ _c , BT _mc , and Bω ₁ , the OR circuit 58 sets the pulsation avoidance flag FLG _pulse to “1”. do. On the other hand, if the vibration amplitudes Aθ _c , AT _mc , and Aω ₁ are all less than the corresponding determination values Bθ _c , BT _mc , and Bω ₁ , the OR circuit 58 sets the pulsation avoidance flag FLG _pulse to “0”.

When the pulsation avoidance flag FLG _pulse is switched from "0" to "1", the _{rotation speed determination unit 60 switches the torque control flag FLG trq} , which is the output signal, from "0" to "1". Further, the rotation speed determination unit 60 latches _{the inverter frequency ω 1 when the torque control flag FLG trq} is switched from “0” to “1”. The latched inverter frequency ω ₁ is called the latch frequency ω _{1 R.} When the torque control flag FLG _trq is “1”, the rotation speed determination unit 60 then monitors the _{inverter frequency ω 1.} Then, when the absolute value of the difference between the _{inverter frequency ω 1} and the latch frequency ω _{1R , that is, | ω 1} −ω _1R | becomes a predetermined value (reset width DW) or more, the torque control flag FLG _trq is changed from “1” to “0”. Switch to.

<Operation of the first embodiment>
Next, the operation of this embodiment will be described.
FIG. 7A is a waveform diagram showing an example of a change in the rotational speed of the motor 4, that is, the mechanical frequency ω _m. As described above, assuming that the number of pole pairs of the motor 4 is Pt, the mechanical frequency ω _m is equal to "ω _m = ω ₁ / Pt". The mechanical frequency ω _m rises with the passage of time, and is _{ω m1 at time t1 and ω m3} at time t3.

7 (b) and 7 (c) are waveform diagrams of _{the torque control flag FLG trq} and the pulsation avoidance flag FLG _{pulse, respectively.} It is assumed that the pulsation avoidance flag FLG _pulse rises to "1" at time t1. _{That is, it is assumed that any of the vibration amplitudes Aθ c} , AT _mc , and Aω ₁ shown in FIG. 5 is equal to or higher than the corresponding determination values Bθ _c , BT _mc , and Bω _1.

Then, at time t1, the rotation speed determination unit 60 _switches the torque control flag FLG trq from “0” to “1”, _{and latches the inverter frequency ω 1} at that time as the latch frequency ω _1R . That is, the mechanical frequency ω _m1 shown in FIG. 7A is equal to “ω _1R / pole logarithm Pt”. After that, at time t2, the pulsation avoidance flag FLG _pulse has fallen to “0”. _{That is, it is assumed that all of the vibration amplitudes Aθ c} , AT _mc , and Aω ₁ shown in FIG. 5 are less than the corresponding determination values Bθ _c , BT _mc , and Bω _1.

However, even at time t2, the rotation speed determination unit 60 _{continues to hold the torque control flag FLG trq} at the previous value (“1”). After that, when the mechanical frequency ω _m becomes ω _m3 (= ω _m1 + reset width DW / pole logarithm Pt) or more at time t3, the rotation speed determination unit 60 is reset and the torque control flag FLG _trq stands at “0”. Go down. The "DW / Pt" may be set to, for example, about 10 rps.

Returning to FIG. 2, the torque control unit 33 _executes torque control when the torque control flag FLG trq is “1”, _{and stops torque control when the FLG trq} is “0”. That is, if the torque control flag FLG _trq is “0”, the torque control unit 33 sets the torque control output current command value I _qsin ^* to zero. On the other hand, when FLG _trq is "1", the torque control unit 33 has a non-zero torque control output current command value I _qsin ^* _{based on the torque pulsation component estimated value ΔT mc output by the torque pulsation estimation unit 31.} Is output. Here, as a method for calculating the torque control output current command value I _qsin ^* , the method described in paragraphs 0029 to 0033 of the above-mentioned Patent Document 1 (Japanese Unexamined Patent Publication No. 2006-180605) can be used.

<Effect of the first embodiment>
As described above, the controller (12) in the present embodiment has a pulsation suppressing unit (33) that suppresses the pulsation generated at the rotation speed of the motor (4) and a pulsation suppressing unit (4) depending on the state of the motor (4). It has a pulsation suppression control unit (32) that sets the on / off state of (33).
This eliminates the need to investigate in advance the conditions under which the pulsation of the motor (4) becomes large, so that appropriate torque control can be realized while suppressing cost increase.

Further, the pulsation suppression control unit (32) controls the magnetic pole position of the motor (4) when the fluctuation range (Aω _{1 ) of the rotation speed (ω 1} ) is equal to or larger than the predetermined rotation speed determination value (Bω _1). When the fluctuation range (Aθ _{c ) of the shaft error (Δθ c} ), which is the difference between the detected magnetic pole position and the detected magnetic pole position, is equal to or greater than the predetermined shaft error pulsation determination value (Bθ _c ), or the torque generated by the motor (4). _{When the fluctuation range (AT mc} ) of the pulsation component (ΔT _mc ) is equal to or larger than the predetermined torque pulsation determination value (BT _mc ), the pulsation suppression unit (33) is set to the ON state.
As a result, it is possible to detect whether or not the pulsation of the motor (4) has increased based on various conditions, and set the pulsation suppression unit (33) to the ON state.

_{Further, the pulsation suppression control unit (32) causes the pulsation suppression unit (33) to change when the rotation speed (ω 1} ) changes by a predetermined reset width (DW) or more after the pulsation suppression unit (33) is set to the ON state. It further has a rotation speed determination unit (60) for setting the off state.
_{As a result, when the rotation speed (ω 1} ) changes significantly after the pulsation suppression unit (33) is set to the on state, the pulsation suppression unit (33) is automatically set to the off state.

[Second Embodiment]
Next, the details of the motor drive system according to the second embodiment of the present invention will be described. In the following description, the parts corresponding to the respective parts of FIGS. 1 to 7 may be designated by the same reference numerals, and the description thereof may be omitted.
The hardware configuration of this embodiment is the same as that of the first embodiment (see FIG. 1). However, in the motor drive system S2 of the present embodiment, the controller 70 shown in FIG. 8 is applied instead of the controller 12 (see FIG. 2) in the first embodiment. Here, FIG. 8 is a block diagram showing an algorithm of the controller 70 according to the present embodiment.

The controller 70 includes a torque pulsation determination unit 72, a pulsation avoidance control unit 74, and an adder 76 in place of the torque control determination unit 32 and the torque control unit 33 in the controller 12 of the first embodiment. ing.

FIG. 9 is a block diagram showing an algorithm of the torque pulsation determination unit 72. The torque pulsation determination unit 72 is obtained by removing the rotation speed determination unit 60 from the torque control determination unit 32 (see FIG. 5) of the first embodiment, and as described above, the pulsation avoidance flag FLG _pulse is set from the OR circuit 58. Output.

Further, FIG. 10 is a block diagram showing an algorithm of the pulsation avoidance control unit 74. The pulsation avoidance control unit 74 includes a multiplier 80, a switch 82, an integrator 84, and a limiter 86.

Here, the multiplier 80 and the switch 82 are supplied with the inverter frequency addition value ΔP, which is a positive value. The multiplier 80 multiplies ΔP by -1 and outputs the result. The switch 82 selects ΔP when the pulsation avoidance flag FLG _pulse is “1” _{and −ΔP when the FLG pulse} is “0”. The integrator 84 integrates the signal supplied from the switch 82. Further, the limiter 86 limits the output of the integrator 84 _{within a range of a predetermined upper limit value P max} and a lower limit value P _min , and outputs the result as an inverter frequency difference value ω _{1 pulse} .

Here, when the pulsation avoidance flag FLG _pulse becomes “1”, the inverter frequency addition value ΔP, which is a positive value, is input to the integrator 84 via the switch 82. As a result, the output of the integrator 84 gradually increases with the passage of time. The limiter 86 outputs this integration result as an inverter frequency difference value ω _{1 pulse.} However, when the integration result becomes the upper limit value P _max or more, the limiter 86 outputs the _{upper limit value P max} as the inverter frequency difference value ω _{1 pulse.}

On the other hand, when the pulsation avoidance flag FLG _pulse becomes “0”, a negative value −ΔP is input to the integrator 84 via the switch 82. As a result, the output of the integrator 84 gradually decreases with the passage of time. The limiter 86 outputs this integration result as an inverter frequency difference value ω _{1 pulse.} However, when the integration result becomes the lower limit value P _min or less, the limiter 86 outputs the _{lower limit value P min} as the inverter frequency difference value ω _{1 pulse.}

Returning to FIG. 8, the adder 76 adds the inverter frequency difference value ω _{1 pulse} and the inverter frequency command value ω ₁ ^*, and the addition result “ω ₁ ^* + ω _{1 pulse} ” is the speed control unit 24 and V _d V _q. It is input to the calculation unit 26. As a result, when the pulsation avoidance flag FLG _pulse is “0” (when _{all of the vibration amplitudes Aθ c} , AT _mc , and Aω ₁ are less than the corresponding judgment values Bθ _c , BT _mc , and Bω ₁ ), the inverter frequency ω. ₁ is a value near "ω ₁ ^* −ω _{1 pulse".} On the other hand, when the pulsation avoidance flag FLG _pulse is “1” (when any of the vibration amplitudes Aθ _c , AT _mc , and Aω ₁ is equal to or greater than the corresponding determination values Bθ _c , BT _mc , and Bω _{1), the inverter.} The frequency ω ₁ is a value near "ω ₁ ^* + ω _{1 pulse".}

In other words, when the vibration of the motor 4 is small, the inverter frequency ω ₁ becomes a value near “ω ₁ ^* −ω _{1 pulse} ”, while when the vibration of the motor 4 is large, the inverter frequency ω ₁ becomes “ω _1”. ^* + Ω _{1 pulse} ”. That is, in the present embodiment, when the vibration of the motor 4 becomes large, the inverter frequency ω ₁ is increased.

When the motor 4 drives a load of a reciprocating compression mechanism, a rotary compression mechanism, or the like (not shown), if the natural frequency of the compression mechanism and the rotation speed of the motor 4 are close to each other, resonance occurs and the vibration of the motor 4 occurs. growing. When resonance occurs, the vibration can be reduced by shifting the rotation speed of the motor 4 from the natural frequency of the compressor. Further, in a rotary compression mechanism or the like, the lower the rotation speed of the motor 4, the more likely it is that the compressor vibrates due to torque pulsation, and the vibration of the compressor can be reduced by increasing the rotation speed of the motor 4. For this reason, when the vibration of the motor 4 is large, it is _{preferable to increase the inverter frequency ω 1} and increase the rotation speed.

Therefore, in the present embodiment, when the pulsation avoidance flag FLG _pulse is "0", the pulsation suppression is turned off, and when the pulsation avoidance flag FLG _pulse is "1", the pulsation suppression is turned on. Will be done.

As described above, according to the present embodiment, the same effect as that of the first embodiment is obtained. Further, according to the present embodiment, the pulsation suppressing unit (74) has a motor (4) when the fluctuation range (Aω _{1 ) of the rotation speed (ω 1} ) is equal to or larger than a predetermined rotation speed determination value (Bω _1). When the fluctuation range (Aθ _{c ) of the shaft error (Δθ c} ), which is the difference between the controlled magnetic pole position and the detected magnetic pole position, is equal to or greater than the predetermined shaft error pulsation determination value (Bθ _{c), or the motor (} When the fluctuation range (AT _{mc ) of the pulsation component (ΔT mc} ) of the torque generated in 4) is equal to or larger than the predetermined torque pulsation determination value (BT _mc ), the rotation speed (ω ₁ ) is changed.
As a result, the rotation speed (ω ₁ ) can be automatically changed and the pulsation of the motor (4) can be suppressed.

[Third Embodiment]
Next, the air conditioner according to the third embodiment of the present invention will be described. FIG. 11 is a refrigeration cycle system diagram of the air conditioner 100 according to the present embodiment.
As shown in FIG. 11, the air conditioner 100 of the present embodiment includes an outdoor unit 110 and an indoor unit 120, and also includes a gas pipe 131 and a liquid pipe 132 for connecting the two.

The outdoor unit 110 includes a compressor 111, a four-way valve 112, an outdoor heat exchanger 113, and an outdoor expansion valve 114. These are sequentially connected by pipes (unsigned). Further, the outdoor unit 110 includes an outdoor electric box 141, an outdoor fan 115, and an outdoor fan motor 116.

Further, the outdoor fan 115 is rotationally driven by the outdoor fan motor 116 to cool the outdoor heat exchanger 113.
The compressor 111 includes a motor 4 and a compression mechanism 35 driven by the motor 4. Further, the outdoor electric box 141 includes the converter circuit 2 according to the first or second embodiment and the inverter device 3.

Further, the indoor unit 120 includes an indoor heat exchanger 123 and an indoor expansion valve 124. Both are connected to each other by piping (unsigned). Further, the indoor unit 120 includes an indoor fan 125, an indoor fan motor 126, and an indoor electric box 142. Further, the indoor fan 125 is rotationally driven by the indoor fan motor 126 to cool the indoor heat exchanger 123. Further, the indoor electric box 142 houses various electric circuits for controlling the inverter of the indoor fan motor 126 and the like. The four-way valve 112 is a valve that switches the flow of the refrigerant, whereby the cooling operation and the heating operation are switched. The outdoor expansion valve 114 and the indoor expansion valve 124 reduce the pressure of the refrigerant to a low temperature and a low pressure.

Next, the operation of the air conditioner 100 in the present embodiment will be described by taking a cooling operation as an example. The arrows shown in each part of FIG. 11 indicate the flow of the refrigerant in the cooling operation of the air conditioner 100.
In the cooling operation, as shown by the solid line, the four-way valve 112 communicates the discharge side of the compressor 111 with the heat exchanger 113, and communicates the suction side of the compressor 111 with the gas pipe 131.

The refrigerant discharged from the compressor 111 is in the form of a high-temperature, high-pressure gaseous. This refrigerant passes through the four-way valve 112 and flows to the heat exchanger 113 side. The gaseous refrigerant flowing into the heat exchanger 113 exchanges heat with the outdoor air supplied by the outdoor fan 115 and is condensed to become a liquid refrigerant. This liquid refrigerant passes through the expansion valve 114 and the liquid pipe 132 in the fully open state, and flows into the indoor unit 120. The liquid refrigerant that has flowed into the indoor unit 120 is decompressed by the indoor expansion valve 124 to become a low-temperature low-pressure gas-liquid mixed refrigerant.

This low-temperature, low-pressure gas-liquid mixed refrigerant flows into the indoor heat exchanger 123, exchanges heat with the indoor air supplied by the indoor fan 125, and evaporates to become a gaseous refrigerant. At this time, the air in the room is cooled by the latent heat of vaporization of the gas-liquid mixed refrigerant, and cold air is sent into the room. After that, the gaseous refrigerant flowing out of the indoor unit 120 passes through the gas pipe 131 and is returned to the outdoor unit 110. The gaseous refrigerant returned to the outdoor unit 110 passes through the four-way valve 112, is sucked into the compressor 111, and is compressed again by the compressor 111 to form a series of refrigeration cycles.

As described above, since the air conditioner 100 of the present embodiment includes the inverter device 3 according to the first embodiment or the second embodiment, the cost increase of the air conditioner 100 is suppressed and the motor 4 is subjected to the above. Appropriate torque control can be realized.

[Modification example]
The present invention is not limited to the above-described embodiment, and various modifications are possible. The above-described embodiments are exemplified for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to delete a part of the configuration of each embodiment, or add / replace another configuration. In addition, the control lines and information lines shown in the figure show what is considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary for the product. In practice, it can be considered that almost all configurations are interconnected. Possible modifications to the above embodiment are, for example, as follows.

(1) Since the hardware of the controllers 12 and 70 in each of the above embodiments can be realized by a general computer, the programs and the like related to the block diagrams shown in FIGS. 2, 5, 5, 9, 9, 10 and the like. Information such as tables and files is stored in a memory, a hard disk, a recording device such as an SSD (Solid State Drive), or a storage medium such as an IC card, an SD card, or a DVD, or distributed via a transmission path. You may.

(2) Further, the algorithms shown in FIGS. 2, 5, 8, 9, 10, 10 and the like are realized as software-like processing using a program in the above embodiment, but some or all of them are realized. It may be replaced with hardware-like processing using ASIC (Application Specific Integrated Circuit), FPGA (field-programmable gate array), or the like.

(3) In the first and second embodiments, the torque control determination unit 32 (see FIG. 5) and the torque pulsation determination unit 72 (see FIG. 8) have an axial error pulsation vibration amplitude Aθ _c and a torque pulsation vibration amplitude AT _mc. , And the value of the pulsation avoidance flag FLG _pulse was set based on the value of the inverter frequency pulsation vibration amplitude Aω _1. However, the method of determining the on / off state of the torque control unit 33 or the pulsation avoidance control unit 74 according to the state of the motor 4 is not limited to the above. For example, a vibration sensor may be attached to the motor 4, and the pulsation avoidance flag FLG _pulse may be set to “1” even when the magnitude of vibration exceeds a predetermined value.

(4) In the second embodiment, the pulsation avoidance control unit 74 switches 82 so _{that the inverter frequency ω 1 is higher when the pulsation avoidance flag FLG pulse} is “1” than when it is “0”. (See FIG. 10) was controlled. However, conversely, when the pulsation avoidance flag FLG _pulse is “1”, the switch 82 may be controlled so _{that the inverter frequency ω 1} is lower than when it is “0”.

(5) Further, the motor drive system of the first and second embodiments is not limited to the air conditioner 100 of the third embodiment, but also a ventilation fan, a refrigerator, a washing machine, a vacuum cleaner, an industrial machine, an electric vehicle, and a railroad vehicle. , Ships, elevators, escalator, etc., can be applied to various electric devices. As a result, in these electric devices, excellent performance can be exhibited according to the application.

4 Motor 12, 70 Controller 32 Torque control judgment unit (pulsation suppression control unit)
33 Torque control unit (pulsation suppression unit)
35 Compression mechanism 60 Rotation speed determination unit 72 Torque pulsation determination unit (pulsation suppression control unit)
74 Pulsation avoidance control unit (pulsation suppression unit)
100 Air conditioner ω ₁ Inverter frequency (rotation speed)
Δθ _c- axis error ΔT _mc Torque pulsation component estimate (torque pulsation component)

Claims (4)

An inverter circuit that converts the supplied DC voltage into an output voltage, which is an AC voltage, and applies it to the motor.
It has a controller that controls the inverter circuit, and has
The controller
A pulsation suppression unit that suppresses pulsation that occurs at the rotational speed of the motor,
A pulsation suppression control unit that sets an on / off state of the pulsation suppression unit according to the state of the motor, and a pulsation suppression control unit.
Have a,
The pulsation suppression control unit
When the fluctuation width of the rotation speed is equal to or more than the predetermined rotation speed determination value, the fluctuation width of the shaft error, which is the difference between the controlled magnetic pole position of the motor and the detected magnetic pole position, is equal to or more than the predetermined shaft error pulsation determination value. If it is, or, if the variation width of the pulsating component of torque the motor generates is predetermined torque pulsation determination value or more, the power conversion device and sets the pulsation suppressing portion in the oN state. The pulsation suppression control unit
The first aspect of the present invention is characterized in that it further includes a rotation speed determination unit that sets the pulsation suppression unit to the off state when the rotation speed changes by a predetermined reset width or more after the pulsation suppression unit is set to the on state. The power converter described. The pulsation suppressing part is
When the fluctuation width of the rotation speed is equal to or more than the predetermined rotation speed determination value, the fluctuation width of the shaft error, which is the difference between the controlled magnetic pole position of the motor and the detected magnetic pole position, is equal to or more than the predetermined shaft error pulsation determination value. If it is, or, if the variation width of the pulsating component of torque the motor generates is predetermined torque pulsation determination value or more, according to claim 1, characterized in that for changing the rotational speed Power converter. It has an inverter circuit that converts the supplied DC voltage into an output voltage that is an AC voltage and applies it to the motor, a controller that controls the inverter circuit, and a compression mechanism that is driven by the motor.
The controller
A pulsation suppression unit that suppresses pulsation that occurs at the rotational speed of the motor,
A pulsation suppression control unit that sets an on / off state of the pulsation suppression unit according to the state of the motor, and a pulsation suppression control unit.
Have a,
The pulsation suppression control unit
When the fluctuation width of the rotation speed is equal to or more than the predetermined rotation speed determination value, the fluctuation width of the shaft error, which is the difference between the controlled magnetic pole position of the motor and the detected magnetic pole position, is equal to or more than the predetermined shaft error pulsation determination value. When the fluctuation range of the pulsation component of the torque generated by the motor is equal to or larger than a predetermined torque pulsation determination value, the pulsation suppression unit is set to the ON state .

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