JP4804496B2 - Electric motor drive, air conditioner, washing machine, washing dryer, refrigerator, ventilation fan, heat pump water heater - Google Patents

Description

  The present invention relates to an apparatus for driving an electric motor.

  Conventionally, regarding the control of the rotation speed of a fan motor, “in an air conditioner, the fan motor is prevented from being stopped due to a load fluctuation of the fan motor and the fan motor can be controlled appropriately. As a technique for the purpose, “a DC voltage is switched by the inverter circuit 3 and applied to the fan motor 4 to control to the target rotational speed. At this time, the phototransistor of the photocoupler circuit 10 is turned on and off according to the current flowing through the shunt resistor R1, and the output voltage of the integrating circuit 11 drops due to this turning on. When the phototransistor is turned off, the output voltage of the integrating circuit 11 is To rise. The microcomputer 13 inputs and detects the output voltage of the integrating circuit 11 through the A / D conversion port (detects the input current of the inverter circuit 3). The target output speed is varied by determining whether the detected output voltage is in a plurality of zones, or the operation of the fan motor is stopped. Is proposed (Patent Document 1).

  In addition, regarding the control of the fan motor, “the controllability to the external load is enhanced and sufficient protection is achieved. As a technique for the purpose of the above, “a rotation speed calculation unit 5 that calculates the current rotation speed based on the cycle of the position signal, a current detection circuit 6 that detects a current in the DC portion of the inverter main circuit 2a, An overload detection / rotation speed reduction control unit 7 for calculating the rotation speed command by performing an overload detection and rotation speed reduction calculation using the rotation speed, an externally supplied rotation speed command, and a detection current as inputs, and the current rotation speed And a rotational speed control unit 8 that calculates a duty command by performing a rotational speed control calculation with the rotational speed command as an input, and a drive signal creation unit 9 that outputs a gate signal with the position signal and the duty command as inputs. Is proposed (Patent Document 2).

  Patent Document 3 below discloses a technique related to sensorless control.

  Non-Patent Document 1 below discloses a method for estimating an axis error in sensorless control of a synchronous motor.

JP 11-51454 A (summary) JP 2001-286179 A (summary) JP 2002-191197 A Electrical Engineering D, Vol.110, No.11, p. 1193-P. 1200, 1990

  In the technique described in Patent Document 1, the target rotational speed of the fan motor is varied according to the input current of the inverter circuit 3, but if the phase of the voltage applied to the fan motor is changed, even under the same load condition The current value changes. Therefore, the torque for driving the load by the fan motor is insufficient, and there is a risk of causing step-out.

In the technique described in Patent Document 2 above, overload detection and rotational speed reduction calculation are performed to calculate the rotational speed command of the fan motor, but the load applied to the fan motor varies greatly due to factors such as outside wind. To do.
In addition, overload detection is performed using the current rotation speed, the rotation speed command supplied from the outside, and the detected current as inputs, but the output voltage phase of the inverter changes even under the same load condition as in the above-mentioned Patent Document 1. Then, since the current value also changes, not only accurate load detection becomes difficult, but there is a risk of stepping out due to insufficient torque.

  The present invention has been made to solve the above-described problems. The torque of the electric motor is obtained based on the operation theory of the electric motor, and the rotational speed of the electric motor is controlled based on the obtained torque. It is an object of the present invention to obtain an electric motor drive device that can prevent adjustment.

An electric motor drive device according to the present invention includes an inverter that applies an AC voltage to the electric motor, a voltage detection unit that detects a voltage that the inverter applies to the electric motor, and a current detection unit that detects a current flowing through the electric motor, Control means for controlling the voltage applied to the electric motor by the inverter, and the control means is a coordinate conversion means for converting the output of the current detection means and the voltage detection means into an orthogonal biaxial coordinate system, and a rotational speed estimation means for estimating a rotation speed of the motor based on the output from the coordinate conversion unit, a torque calculating means for obtaining by calculation the torque of the motor based on the output of the previous SL coordinate transformation hand stage and the rotation speed estimation means And a rotation speed control means for controlling the rotation speed of the electric motor based on the calculated value obtained by the torque calculation means.

  According to the motor drive device of the present invention, the torque generated in the motor can be obtained based on the operation theory of the motor, and the motor can be operated at the optimum rotational speed. Further, by increasing the rotational speed up to the limit torque, the capability of the device can be improved, or the rotational speed can be controlled so as to operate at an optimum torque according to the load, thereby preventing step-out due to insufficient torque.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a motor drive device 2 according to Embodiment 1 of the present invention.
In FIG. 1, 1 is a DC power source, 2 is a drive device for an electric motor according to the first embodiment, and 3 is an electric motor.

FIG. 2 is an analysis model diagram of the motor 1. In FIG. 2, U-phase, V-phase, and W-phase armature winding fixed axes are shown. Reference numeral 4 denotes a permanent magnet constituting the rotor of the electric motor 3.
In a rotating coordinate system that rotates at the same speed as the magnetic flux produced by the permanent magnet 4, the direction of the magnetic flux produced by the permanent magnet 4 is taken as the d-axis, and the estimated control axis corresponding to the d-axis is taken as the γ-axis. Although not shown, the q axis is taken as a phase advanced by 90 degrees in electrical angle from the d axis, and the estimated δ axis is taken as phase advanced by 90 degrees in electrical angle from the γ axis.
The coordinate axis of the rotating coordinate system in which the d axis and the q axis are selected as the coordinate axes is referred to as the dq axis. The rotating coordinate system for control by the inverter is a coordinate system in which the γ axis and the δ axis are selected as coordinate axes, and the coordinate axes are called γδ axes.

The dq axis is rotating, and the rotation speed of the electric motor 3 that is the rotation speed is called the electric motor rotation speed ω. The γδ axis is also rotating, and the rotation speed is called an inverter rotation speed ω1.
In addition, in the dq axis rotating at a certain moment, the phase of the d axis is represented by the motor rotation phase θ with reference to the U-phase armature winding fixed axis.
Similarly, in the γδ axis that is rotating at a certain moment, the phase of the γ axis is expressed by the inverter rotation phase θ1 with the U-phase armature winding fixed axis as a reference.
An axial error Δθ between the d-axis and the γ-axis is expressed by Δθ = θ−θ1.

The γδ axis is a coordinate axis obtained as a result of estimating the dq axis. In actual operation, there may be a case where the axis error Δθ is small. In this case, the dq axis and the γδ axis can be regarded as the same.
Therefore, unless otherwise specified, the control operation will be described using values on the dq axis, but it goes without saying that the same configuration can be realized using values on the γδ axis.
In this case, it goes without saying that the motor rotational speed ω may be replaced with the inverter rotational speed ω1 and the motor rotational phase θ may be replaced with the inverter rotational phase θ1.

FIG. 3 is a configuration diagram of the electric motor drive device 2 according to the first embodiment.
The electric motor drive device 2 includes an inverter main circuit 5, current detection means 6, DC voltage detection means 7, and inverter control means 8.

  The inverter main circuit 5 includes switching elements such as IGBTs and MOSFETs, and each switching element includes a free-wheeling diode connected in parallel. Further, the DC power supplied from the DC power source 1 is converted into AC and an AC voltage is applied to the motor 3.

The current detection means 6 detects the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw flowing into the electric motor 3 and outputs them to the inverter control means 8.
The DC voltage detection means 7 detects the voltage Vdc of the DC power supply 1 and outputs it to the inverter control means 8.
The inverter control means 8 outputs a drive signal based on the outputs of the current detection means 6 and the DC voltage detection means 7 and controls on / off of the switching elements in the inverter main circuit 5.
The inverter control means 8 can be configured by hardware such as a circuit device that realizes the function, or can be configured by an arithmetic device such as a microcomputer or a CPU, and software that defines the operation thereof. The same applies to each means provided in the inverter control means 8 described below.

  The inverter control means 8 includes coordinate conversion means 9, torque calculation means 10, rotation speed control means 11, and applied voltage control means 12.

  The coordinate conversion means 9 uses the electric motor rotation phase θ obtained from the applied voltage control means 12 to convert the currents (Iu, Iv, Iw) output from the current detection means 6 into the d-axis current Id and the q-axis current Iq. Convert to and output.

  The torque calculation means 10 is based on the outputs (Id, Iq) from the coordinate conversion means 9, the dq axis voltage command values Vd *, Vq * output from the applied voltage control means 12, and the motor rotation speed ω of the motor. The torque τm of the electric motor is obtained by calculation. A method of calculating τm will be described later.

  The rotation speed control means 11 outputs a second rotation speed command ω ** based on the motor torque τm output from the torque calculation means 10 and the rotation speed command ω *. Details of the rotation speed control means 11 will be described later.

  The applied voltage control unit 12 includes an output voltage vector calculation unit 13, a voltage / phase command calculation unit 14, and a drive signal generation unit 15.

Based on the second rotational speed command ω **, the d-axis current command Id *, the dq-axis currents Id and Iq, the output voltage vector calculation means 13 determines the motor rotational speed ω, the motor rotational phase θ, and the dq-axis voltage command Vd. * And Vq * are calculated and output to each means.
For these calculation procedures, for example, a technique as described in Patent Document 3 can be used. The motor rotation phase θ is obtained by integrating the motor rotation speed ω over time.

The “rotation speed estimation means” in the first embodiment corresponds to the function in which the output voltage vector calculation means 13 calculates the motor rotation speed ω by calculation.
Further, the “voltage command value calculation means” in the first embodiment corresponds to the output voltage vector calculation means 13.

  The voltage / phase command calculating means 14 is based on the bus voltage Vdc, the dq axis voltage commands Vd *, Vq *, and the motor rotation phase θ, which are outputs of the DC voltage detecting means 7, and the voltage command V * and the phase command θ *. Is output.

  The drive signal generation unit 15 outputs a drive signal based on the voltage command V * and the phase command θ *, which are outputs of the voltage / phase command calculation unit 14, operates the inverter main circuit 5, and drives the electric motor 3. To drive.

Here, an example of a torque calculation method in the torque calculation means 10 will be described.
The voltage / current equation of the electric motor 3 is expressed by the following equation (1).

For the sake of simplicity, assuming the steady state and ignoring the term related to the differential operator p, the following equation (2) is obtained.

FIG. 4 is a vector diagram of the electric motor. From FIG. 4, the d-axis magnetic flux φd and the q-axis magnetic flux φq are expressed by the following equation (3), and when equation (3) is applied to equation (2), equation (4) is obtained.

When equation (4) is solved for φd and φq, the following equation (5) is obtained.

The torque τm of the electric motor is obtained by the following equation (6) by the outer product of the magnetic flux vector and the current vector.

また、式（６）に式（３）を適用することで、次式（８）でも電動機のトルクτｍを求めることが可能である。

ただし、突極性の無いＳＰＭモータ（Ｌｄ＝Ｌｑ）の場合、式（８）は次式（９）となる。

By applying the equation (5) to the equation (6), it becomes possible to obtain the torque τm of the motor by the following equation (7).

Further, by applying the expression (3) to the expression (6), the torque τm of the electric motor can be obtained by the following expression (8).

However, in the case of an SPM motor without saliency (Ld = Lq), equation (8) becomes the following equation (9).

The torque calculation means 10 can obtain the torque τm of the motor by calculation by using any of the above formulas (7), (8), and (9).
Further, when Expression (8) and Expression (9) are used, calculation is possible only with the d-axis current Id and q-axis current Iq, which are the outputs of the coordinate conversion means 9, and constants specific to the motor. Compared with Expression (7), the calculation load is reduced. For this reason, it is possible to reduce the size of the device and reduce the calculation load of an arithmetic device represented by a microcomputer.

There is no problem even if dq-axis voltage commands Vd * and Vq * are used instead of the dq-axis voltages Vd and Vq in the equations (7) to (9), and instead of the dq-axis currents Id and Iq, the dq-axis Needless to say, there is no problem even if the inverter rotational speed ω1, the rotational speed command ω *, or the second rotational speed command ω ** is used instead of the current commands Id * and Iq * and the motor rotational speed ω.
Further, as described above, it goes without saying that there is no problem even if the value of the γδ axis is used instead of the dq axis. Furthermore, although the values of the dq axis and the γδ axis are used this time, it goes without saying that the torque of the electric motor 3 may be obtained using the values of the three phases (UVW) and the orthogonal coordinate axes (αβ).
The same applies to the following description and embodiments.

FIG. 5 is a configuration example of the rotation speed control means 11.
In FIG. 5, the rotational speed control means 11 includes a PI controller 16, PI-controls a deviation Δτ between the torque command τ * and the torque τm of the electric motor 3, obtains a speed compensation amount Δω, and adds it to the rotational speed command ω *. Thus, the second rotational speed command ω ** is obtained.

According to the configuration of FIG. 5, if the motor torque τm increases with respect to the torque command τ *, Δτ becomes negative and the speed compensation amount Δω also becomes negative. Therefore, the second speed command ω ** rotates. The speed becomes smaller than the speed command ω *, and the rotational speed ω of the motor decreases until τ * = τm.
On the other hand, if the motor torque τm is smaller than the torque command τ *, Δτ becomes positive and the speed compensation amount Δω also becomes positive. Therefore, the second speed command ω ** is greater than the rotational speed command ω *. Therefore, the rotational speed ω of the electric motor increases until τ * = τm.
Thus, by controlling the motor torque τm so as to keep the torque command τ * constant, the operation of the motor can be continued without causing torque shortage when the load increases. Further, when the load is reduced, the rotational speed ω can be increased up to the upper limit of operation, so that the capability of the device can be improved.

  Next, the control of the torque and the rotation speed of the electric motor 3 will be described together with the correlation between the two using the following FIGS.

FIG. 6 shows an example of torque and rotation speed control operation in a conventional motor drive device. In FIG. 6, the horizontal axis represents the rotational speed of the motor, and the vertical axis represents the torque required for the motor with respect to the rotational speed. τ _limit is a limit value of torque that can be output by the electric motor.
Normally, the motor drive device can drive the load with a torque of τ _limit or less. However, when the load increases for some reason, the motor torque is increased to drive the load. However, when the torque of the electric motor reaches τ _limit , no more torque can be output, so that step-out occurs and the operation cannot be continued.

FIG. 7 shows an example of torque and rotational speed control operation in the electric motor drive device 2 according to the first embodiment.
As shown in FIG. 7, the electric motor drive device 2 according to the first embodiment obtains the second rotational speed command ω ** so that τ * is constant when the load increases, and the rotational speed becomes ω **. By controlling so as to be, the operation can be continued without falling short of torque, and a highly reliable control can be realized.
Moreover, since a large current can be suppressed by operating the electric motor 3 with an optimum torque, energy saving can also be realized.

FIG. 8 shows another configuration example of the rotation speed control means 11.
FIG. 5 shows an example in which the torque command τ * is given and the deviation Δτ from the torque τm of the electric motor 3 is PI-controlled, but as shown in FIG. 8, the torque command τ corresponding to the value of the rotational speed ω *. A torque command storage means 17 that stores * may be provided, and when a rotational speed ω * is input, a torque command τ * corresponding to the rotational speed ω * may be automatically obtained.
The content stored in the torque command storage means 17 is correlation data between the rotational speed ω * and the torque command τ * as described with reference to FIGS.

FIG. 9 is a configuration example of the PI controller 16 provided in the rotation speed control means 11. 18 is a proportional control gain, and 19 is an integral control gain.
By providing the PI controller 16 with an integrator 20 with a limiter and a limiter 21 and limiting the speed compensation amount Δω, an increase or decrease in the rotational speed ω can be suppressed.
The PI controller 16 in FIG. 9 enables the following operation.

(1) When the motor torque τm is small with respect to the torque command τ *, Δτ becomes positive and the speed compensation amount Δω also becomes positive. Therefore, the rotation speed ω increases during normal operation. However, even in such a case, there is a case where it is not desired to increase the rotational speed ω.
In view of this, the control of the speed compensation amount Δω is suppressed by the function of the limiter so that the rotational speed ω is not increased.

(2) When the motor torque τm is larger than the torque command τ *, Δτ is negative and the speed compensation amount Δω is also negative. For this reason, the rotational speed ω is reduced in order to avoid torque shortage, as in the operation described with reference to FIGS.

The torque command τ * can also be calculated using the following equation (10) obtained based on the above equation (9).
By calculating using Expression (10), it is possible to control the rotation speed without falling into overcurrent interruption due to the current exceeding I _limit . Further, it is possible to suppress the demagnetization and temperature rise of the electric motor 3 and to obtain a highly reliable electric motor driving device 2 with little deterioration over time.

  Needless to say, there is no problem even if the d-axis current command value Id * is used instead of the d-axis current Id. Needless to say, there is no problem even if the torque command τ * is obtained from the equations (7) and (8).

  Further, when the rotational speed control means 11 controls the rotational speed, it is possible to suppress an increase in noise by controlling the rotational speed so as to avoid the vicinity of the resonance point of the electric motor 3 and the connected load. Become. The same applies to the following embodiments.

  As described above, according to the first embodiment, the torque generated in the electric motor 3 can be obtained by calculation based on the operation theory of the electric motor, and the electric motor 3 can be driven with the optimum torque using this.

Embodiment 2. FIG.
In the first embodiment, the configuration for calculating the torque based on the output of the current detection means 6 has been described.
In Embodiment 2 of the present invention, instead of obtaining the motor voltage (Vd, Vq) by calculation by detecting the applied voltage in addition to the current flowing in the motor 3, the actual output voltage is detected and the motor is detected. A configuration for calculating the torque 3 will be described.

FIG. 10 is a configuration diagram of the electric motor drive device 2 according to the second embodiment.
10, in addition to the configuration described in FIG. 3 of the first embodiment, a voltage detection unit 31 is newly provided. Further, another coordinate conversion means 9 is newly provided corresponding to the voltage detection means 31. For convenience of description, two coordinate conversion means 9 are shown in FIG. 10, but they may be integrally formed.

The voltage detection unit 31 detects the U-phase voltage Vu, the V-phase voltage Vv, and the W-phase voltage Vw applied to the electric motor 3 and outputs them to the inverter control unit 8.
The coordinate conversion means 9 uses the current (Vu, Vv, Vw) output from the voltage detection means 31 as the d-axis voltage Vd and the q-axis voltage Vq using the motor rotation phase θ obtained from the applied voltage control means 12. Convert to and output.

The torque calculation means 10 calculates the motor torque τm by calculation based on the outputs (Id, Iq), (Vd, Vq) from the coordinate conversion means 9 and the motor rotation speed ω output from the applied voltage control means 12. . The calculation method of τm is the same as that in the first embodiment.
Since (Vd, Vq) based on the detection value of the voltage detection means 31 is obtained, unlike the first embodiment, the dq axis voltage commands Vd *, Vq * are calculated from the output voltage vector calculation means 13 when calculating the torque τm. There is no need to receive.

  Other configurations are the same as those described in FIG. 3 of the first embodiment, and thus description thereof is omitted.

  As described above, according to the second embodiment, the torque calculation means 10 calculates the torque τm of the electric motor 3 based on the result of the voltage detection means 31 detecting the voltage applied to the electric motor 3, so the dq axis Compared to the configuration for calculating the torque τm based on the voltage commands Vd * and Vq *, the torque τm can be calculated with high accuracy.

Further, according to the second embodiment, the actual output voltage of the inverter main circuit 5 is detected, so that the torque is not affected by the voltage error caused by the dead time of the switching element included in the inverter main circuit 5. It is possible to perform the operation.
Thereby, the calculation accuracy of the torque is improved, and it becomes possible to construct a highly reliable electric motor drive device.
It should be noted that the dead time of the switching element will be described again in an embodiment described later.

Embodiment 3 FIG.
In the second embodiment, the configuration for improving the accuracy of torque calculation using the current detection means 6 and the voltage detection means 31 has been described.
In the third embodiment of the present invention, a configuration for calculating the motor torque τm using the actual rotation speed ω and the rotation phase θ by detecting the rotation information of the motor 3 in addition to the current flowing through the motor 3 will be described. To do.

FIG. 11 is a configuration diagram of the electric motor drive device 2 according to the third embodiment.
In FIG. 11, in addition to the configuration described in FIG. 3 of the first embodiment, a rotation detection means 32 is newly provided.
The rotation detection means 32 detects the rotation phase θ of the electric motor 3 and outputs it to the coordinate conversion means 9 and the voltage / phase command calculation means 14. Further, the rotational speed ω of the electric motor 3 is detected and output to the torque calculation means 10.

The coordinate conversion unit 9 converts the current (Iu, Iv, Iw) output from the current detection unit 6 into a d-axis current Id and a q-axis current Iq using the motor rotation phase θ obtained from the rotation detection unit 32. Convert and output.
Since the motor rotation phase θ based on the detection value of the rotation detection unit 32 is obtained, unlike the first embodiment, it is not necessary to receive the motor rotation phase θ from the applied voltage control unit 12 during coordinate conversion.

The torque calculation means 10 includes outputs (Id, Iq) from the coordinate conversion means 9, dq axis voltage command values Vd * and Vq * output from the applied voltage control means 12, and the motor rotation speed output from the rotation detection means 32. Based on ω, the torque τm of the motor is obtained by calculation. The calculation method of τm is the same as that in the first embodiment.
Since the motor rotation speed ω based on the detection value of the rotation detection unit 32 is obtained, unlike the first embodiment, it is not necessary to receive the motor rotation speed ω from the applied voltage control unit 12 when calculating the torque τm.

  Other configurations are the same as those described in FIG. 3 of the first embodiment, and thus description thereof is omitted.

  As described above, according to the third embodiment, the coordinate conversion unit 9 performs coordinate conversion using the motor rotation phase θ detected by the rotation detection unit 32, and thus the applied voltage control unit 12 obtains the calculation. Compared with the configuration using θ, (Id, Iq) with high accuracy can be obtained, and a highly reliable motor drive device can be constructed.

  Further, according to the third embodiment, the torque calculation means 10 calculates the torque τm of the electric motor 3 using the electric motor rotation speed ω detected by the rotation detection means 32, so that the applied voltage control means 12 obtains it by calculation. Compared to the configuration using ω, the torque τm can be calculated with high accuracy, and a highly reliable motor drive device can be constructed.

Embodiment 4 FIG.
In the fourth embodiment of the present invention, the motor voltage (Vd, Vq), the rotation phase θ, etc. are obtained by calculation by detecting the applied voltage and the rotation information of the motor 3 in addition to the current flowing through the motor 3. Instead, a configuration for calculating the torque τm of the electric motor 3 using these actual values will be described.

FIG. 12 is a configuration diagram of the electric motor drive device 2 according to the fourth embodiment.
In FIG. 12, in addition to the configuration described in FIG. 10 of the second embodiment, a rotation detection unit 32 described in FIG. 11 of the third embodiment is newly provided.
The rotation detection means 32 detects the rotation phase θ of the electric motor 3 and outputs it to the two coordinate conversion means 9 and the voltage / phase command calculation means 14. Further, the rotational speed ω of the electric motor 3 is detected and output to the torque calculation means 10.

The coordinate conversion unit 9 obtains the current (Iu, Iv, Iw) output from the current detection unit 6 and the voltage (Vu, Vv, Vw) output from the voltage detection unit 31 from the rotation detection unit 32. Using the motor rotation phase θ, it is converted into dq-axis current (Id, Iq) and dq-axis voltage (Vd, Vq), respectively, and output.
Since the motor rotation phase θ based on the detection value of the rotation detection means 32 is obtained, unlike the second embodiment, it is not necessary to receive the motor rotation phase θ from the applied voltage control means 12 during coordinate conversion.

The torque calculation means 10 calculates the motor torque τm by calculation based on the outputs (Id, Iq) and (Vd, Vq) from the coordinate conversion means 9 and the motor rotation speed ω output from the rotation detection means 32. The calculation method of τm is the same as that in the first embodiment.
Since the motor rotation speed ω based on the detection value of the rotation detection unit 32 is obtained, unlike the second embodiment, it is not necessary to receive the motor rotation speed ω from the applied voltage control unit 12 when calculating the torque τm.

  Other configurations are the same as those described with reference to FIG. 10 of the second embodiment, and thus description thereof is omitted.

  As described above, according to the fourth embodiment, the coordinate conversion means 9 performs the coordinate conversion using the motor rotation phase θ detected by the rotation detection means 32, so that the applied voltage control means 12 obtains the calculation. Compared with the configuration using θ, (Id, Iq) and (Vd, Vq) with higher accuracy can be obtained, and a highly reliable motor drive device can be constructed.

  Further, according to the fourth embodiment, the torque calculation means 10 calculates the torque τm of the electric motor 3 using the electric motor rotation speed ω detected by the rotation detection means 32, so that the applied voltage control means 12 obtains it by calculation. Compared to the configuration using ω, the torque τm can be calculated with high accuracy, and a highly reliable motor drive device can be constructed.

Embodiment 5 FIG.
In the first to fourth embodiments, it is assumed that the axis error Δθ between the dq axis and the γδ axis is very small, and the torque calculation means 10 obtains the torque τm of the electric motor 3 by calculation under the assumption, and the rotation speed control means 11 has described the configuration for controlling the rotational speed ω of the electric motor 3 based on the torque calculation value.
In the fifth embodiment of the present invention, a configuration for controlling the torque calculation means 10 and the motor rotation speed ω when the axis error Δθ cannot be ignored will be described.

FIG. 13 is a configuration diagram of the electric motor drive device 2 according to the fifth embodiment.
In FIG. 13, in addition to the configuration described in FIG. 3 of the first embodiment, an axis error calculation unit 22 and a coordinate conversion correction unit 23 are newly provided. Other configurations are the same as those described in FIG. 3 of the first embodiment, and thus the same reference numerals as those in FIG.

First, the axis error calculation means 22 will be described.
The voltage equation of the electric motor 3 when the shaft error Δθ cannot be ignored is expressed by the following equation (11). However, for the sake of simplicity, a steady state is assumed and the term relating to the differential operator p is ignored.

When the above equation (11) is solved for Δθ, the following equation (12) is obtained.

The axis error calculation means 22 can obtain the axis error Δθ using the equation (12).
Needless to say, there is no problem even if the γ-axis voltage command Vγ * and the δ-axis voltage command Vδ * are used instead of the γ-axis voltage Vγ and the δ-axis voltage Vδ.
In addition, the axis error Δθ may be obtained by a known technique described in Non-Patent Document 1.

In the case of a motor drive device that controls the γ-axis magnetic flux φγ to be equal to the induced voltage constant φf and controls the δ-axis magnetic flux to zero, the axis error Δθ can be obtained by a simpler equation.
First, the γ-axis magnetic flux φγ and the δ-axis magnetic flux φδ are expressed by the following equation (13).

By the above control, φγ = φf and φδ = 0, so the following equation (14) is obtained.

When the above equation (14) is solved for Δθ, the following equation (15) is obtained.

The axis error calculation means 22 can obtain the axis error Δθ using the equation (15).
When the above equation (15) is used, the axial error Δθ can be obtained more easily than the equation (12), and the calculation load is reduced. For this reason, it is possible to reduce the size of the device and reduce the calculation load of an arithmetic device represented by a microcomputer.

Next, the coordinate conversion correction means 23 will be described.
When the axis error Δθ has a magnitude that cannot be ignored, Iq ≠ Iδ. Therefore, in the equations (7) to (9) described in the first embodiment, an accurate motor torque τm cannot be obtained. Therefore, a method for obtaining Id and Iq using Iγ, Iδ, and Δθ will be described.

FIG. 14 shows the relationship between currents on the γδ axis and the dq axis.
Values on the d-axis of Iγ and Iδ are expressed as IγcosΔθ and IδsinΔθ, respectively, using an axial error Δθ. Similarly, values on the q-axis are expressed as IγsinΔθ and IδcosΔθ, respectively, using the axis error Δθ.
Therefore, Id and Iq can be obtained by the following equations (16) to (17).

Further, Vγ and Vδ can be obtained by the following equations (18) to (19).

By applying Expressions (16) to (19) to Expressions (7) to (9), the torque calculator 10 can obtain an accurate torque even when the axis error Δθ cannot be ignored. .
Therefore, by correcting the γδ axis current to the current on the dq axis by the axis error calculation means 22 and the coordinate conversion correction means 23, the torque of the electric motor 3 can be obtained as in the first embodiment, and the rotational speed control is performed. The number of revolutions can be controlled by the means 11.

  In the fifth embodiment, in addition to the configuration of the first embodiment, an example in which the axis error calculation means 22 and the coordinate conversion correction means 23 are newly provided has been described. However, the same applies to other embodiments. The shaft error calculation means 22 and the coordinate conversion correction means 23 are provided, and the motor torque τm can be accurately obtained even when the shaft error Δθ cannot be ignored.

Embodiment 6 FIG.
In the fifth embodiment, the configuration for controlling the motor torque τm and the rotation speed on the assumption that the axis error Δθ cannot be ignored has been described.
In the sixth embodiment of the present invention, a configuration in which the influence of the axis error Δθ is reduced by controlling the axis error Δθ to be zero will be described.

FIG. 15 is a configuration diagram of the electric motor drive device 2 according to the sixth embodiment.
In FIG. 15, in addition to the configuration described in FIG. 3 of the first embodiment, an axis error calculation means 22 is newly provided. Other configurations are the same as those described in FIG. 3 of the first embodiment, and thus the same reference numerals as those in FIG.
The operation of the axis error calculation means 22 is the same as that described in the fifth embodiment.
Hereinafter, a method for controlling the axis error Δθ to be zero under the configuration of FIG. 15 will be described.

FIG. 16 is a configuration example of the output voltage vector calculation means 13.
The output voltage vector calculator 13 includes an output voltage vector calculator 24, a proportional controller 25, and an integrator 26.

Based on the second rotational speed command ω **, the γ-axis current command Iγ *, the γ-axis current Iγ, and the δ-axis current Iδ, the output voltage vector calculator 24 generates a γ-axis voltage command Vγ * and a δ-axis voltage command. Vδ * is obtained.
The axis error calculation means 22 calculates the axis error Δθ based on Vγ *, Vδ *, Iγ, Iδ, and the rotational speed ω.

In order to control the axial error Δθ to zero, the proportional controller 25 performs proportional control using a deviation between Δθ and zero to obtain a speed compensation amount Δω.
Further, the rotational speed ω is obtained from the deviation between the second rotational speed command ω ** and Δω, and the integrator 26 integrates ω to obtain the rotational phase θ.
After obtaining the rotational phase θ, it is possible to control the axial error Δθ to be zero by controlling the phase of the γδ axis to be close to this.

By controlling the axial error Δθ to be zero, the γδ axis and the dq axis coincide with each other, so that Iγ = Id, Iδ = Iq, Vγ = Vd, Vδ = Vq, and the equations (7) to (9) It is possible to reduce the calculation error in the torque calculation formula.
Further, as described in the fifth embodiment, it is not necessary to correct the value on the γδ axis to the value on the dq axis, so that the calculation load can be reduced. For this reason, it is possible to reduce the size of the device and reduce the calculation load of an arithmetic device represented by a microcomputer.

  In the sixth embodiment, in addition to the configuration described in FIG. 3 of the first embodiment, the configuration in which the axis error calculation means 22 is newly provided has been described. A calculation unit 22 may be provided so that the axis error Δθ is controlled to be zero.

Embodiment 7 FIG.
In the seventh embodiment of the present invention, a method of reducing the influence of the short-circuit prevention time (dead time) provided for preventing the short circuit of the upper and lower switching elements on the control when the inverter main circuit 5 is driven will be described.

FIG. 17 is a configuration example of the inverter main circuit 5.
In FIG. 17, the inverter main circuit 5 includes six switching elements 27a to 27f and six freewheeling diodes 28a to 28f. Hereinafter, an operation example and the dead time of the inverter main circuit 5 will be briefly described.

For example, if the switching element 27d is turned on at the moment when the switching element 27a is turned off, there is a possibility that a time during which the switching element 27d is turned on may occur, and the inverter main circuit 5 may be destroyed.
Therefore, as shown in FIG. 17, a dead time for turning off the switching element 27d is provided, and the on / off timing is controlled so that the upper and lower switching elements do not turn on at the same time, thereby preventing destruction of the inverter. Techniques are commonly used.

However, if the dead time period is provided, the drive signal is deleted, so that the voltage that the inverter main circuit 5 should originally output cannot be output, and there is a problem that the voltage command and the actual output voltage value do not match.
Due to this, when the voltage command values Vd * and Vq * of the d-axis and q-axis are used in the above torque calculation expressions (7) to (9), for example, this is the actual output voltage value. There is a possibility that Vd and Vq do not match and accurate torque cannot be obtained.
Hereinafter, a configuration for correcting the dead time will be described.

FIG. 18 is a configuration diagram of the electric motor drive device 2 according to the seventh embodiment.
In FIG. 18, in addition to the configuration described in FIG. 3 of the first embodiment, a dead time correcting means 29 is newly provided. Other configurations are the same as those described in FIG. 3 of the first embodiment, and thus the same reference numerals as those in FIG.

The dead time correction means 29 generates dead time correction amounts ΔVu, ΔVv, ΔVw based on the U phase, V phase, and W phase currents Iu, Iv, Iw, and outputs them to the drive signal generation means 15. Correct voltage error caused by dead time.
As a result, the voltage command and the actual output voltage value can be matched, and the torque calculation error can be reduced.

なお、ｓｉｇｎ関数は、次式（２１）で表される。

FIG. 19 explains the correction of the dead time error.
The Td correction amounts ΔVu to ΔVw in the UVW phase shown in FIG. 19 are expressed by the following equation (20).

The sign function is expressed by the following equation (21).

  The dead time correction means 29 can obtain the Td correction amounts ΔVu to ΔVw in the UVW phase by using the above equations (20) to (21), and can perform the dead time correction using this.

Embodiment 8 FIG.
In the eighth embodiment of the present invention, in addition to the method of correcting the dead time for the drive signal output from the inverter control means 8, the voltage error generated on the dq axis due to the dead time is taken into consideration, so that the actual voltage dq axis is A _method for estimating the voltages V _{d_real} and V _{q_real} and calculating the torque of the motor 3 with high accuracy will be described.

FIG. 20 is a configuration diagram of the electric motor drive device 2 according to the eighth embodiment.
In FIG. 20, a voltage error estimating means 30 is newly provided in addition to the configuration described in FIG. 3 of the first embodiment. Other configurations are the same as those described in FIG. 3 of the first embodiment, and thus the same reference numerals as those in FIG.
Next, an error estimation formula used by the voltage error estimation unit 30 will be described.
The “dead time correcting means” in the eighth embodiment corresponds to the voltage error estimating means 30.

V _{d_real} and V _{q_real} are expressed by the following equation (22) using voltage errors ΔVd and ΔVq of the dq axis.

Next, how to obtain V _{d_real} and V _{q_real} will be described.
According to the configuration of FIG. 20, the drive signal generation means 15 corrects the voltage error due to the dead time using the dead time correction amount and then outputs the drive signal, so that the voltage command and the actual output voltage value are output. Can be matched.
That is, the dead time correction amount can be regarded as a voltage error caused by the dead time.
Since equation (20) is the value of the UVW phase, as shown in the following equation (23), conversion is performed to αβ axis values ΔVα and ΔVβ of the orthogonal stator coordinates.

Further, using the rotational phase θ, the equation (23) can be converted into a value on the dq axis by the following equation (24).

The voltage error estimating means 30 can obtain V _{d_real} and V _{q_real} by applying ΔVd and ΔVq obtained by the equation (24) to the equation (22).

  The method for calculating the voltage error due to dead time correction and dead time described in the seventh to eighth embodiments is merely an example, and it goes without saying that there is no problem even if other methods are used.

In the seventh to eighth embodiments, in addition to the configuration described in FIG. 3 of the first embodiment, a configuration in which a dead time correction unit 29 and a voltage error estimation unit 30 are newly provided has been described. However, other embodiments are described. Similarly, the dead time correcting means 29 and the voltage error estimating means 30 may be provided to compensate for the influence of the dead time.
However, in the configuration in which the voltage detection unit 31 is provided, the effect of compensating for the voltage error due to the dead time is small compared to the configuration in which the voltage detection unit 31 is not provided.

Embodiment 9 FIG.
As examples of use of the motor drive device described in the first to eighth embodiments, an air conditioner, a washing machine, a washing dryer, a refrigerator, a ventilation fan, a heat pump water heater, a pump, an elevator, an FA, an inverter for a hand dryer Is mentioned.

In an air conditioner, if the heating operation is performed in a state where the temperature is low, the heat exchanger of the outdoor unit becomes frosted and clogged, so the torque of the fan motor for heat exchange increases, and the current increases. Although there is a problem that the operation cannot be continued due to the overcurrent trip, the operation can be continued without falling into the overcurrent trip by using the present invention.
For example, an abnormality detecting means for monitoring the calculated value of the torque calculating means 10 to detect an increase in torque is provided in the drive device 2 of the electric motor, and a signal to that effect is output when an increase in torque is detected. That's fine.

Further, when an increase in the torque of the fan motor is detected, a signal indicating that the defrosting operation for removing the frost of the heat exchanger should be performed is output from the abnormality detection means, and a system is configured to suppress the reduction in efficiency. Also good.
In addition, even when the defrosting operation is performed, if the fan motor torque remains increased, the heat exchanger may be deformed, etc., so that the user is informed to be repaired. Also good.

  Furthermore, when the torque of the electric motor that drives the indoor unit fan of the air conditioner increases, it is judged that the filter is clogged with dust or the like, and a signal indicating that the filter should be cleaned is abnormal. You may comprise so that it may output from a detection means.

Furthermore, the load torque of an electric motor that drives a motor for a ventilation fan, a washing machine, or a fan for drying a washing and drying machine changes when dust collection or lint filter clogging occurs.
Therefore, it is possible to configure an abnormality detection means for detecting clogging of the filter by detecting the torque of the electric motor. Further, when the abnormality detecting means detects clogging of the filter, a signal indicating that the filter should be cleaned may be output.

  In addition, when operating a pump that sends liquid, clogging may occur when foreign matter is mixed in, and liquid may not be sent. Therefore, it is possible to configure an abnormality detection means that detects an increase in the torque of the pump motor and detects foreign matter contamination to notify the abnormality.

When an abnormality such as clogging described above is detected, an electrical signal is issued and the user is notified by an alarm or display, so that the user can be immediately notified of the abnormality and take countermeasures. It becomes possible to make it.
Further, by stopping the operation of the device when an abnormality is detected, it is possible to prevent a device failure and the like, and a highly reliable device can be realized. Moreover, power consumption can be reduced by avoiding operation in an abnormal state.

1 is a configuration diagram of an electric motor drive device 2 according to Embodiment 1. FIG. 2 is an analysis model diagram of the motor 1. FIG. 1 is a configuration diagram of an electric motor drive device 2 according to Embodiment 1. FIG. It is a vector diagram of an electric motor. 2 is a configuration example of a rotation speed control means 11. An example of a control operation of torque and rotational speed in a conventional motor driving device is shown. 3 shows an example of torque and rotation speed control operation in the electric motor drive device 2 according to the first embodiment. 5 is another configuration example of the rotation speed control means 11. It is a structural example of PI controller 16 with which the rotation speed control means 11 is provided. FIG. 6 is a configuration diagram of an electric motor drive device 2 according to a second embodiment. FIG. 6 is a configuration diagram of a motor drive device 2 according to a third embodiment. FIG. 6 is a configuration diagram of an electric motor drive device 2 according to a fourth embodiment. FIG. 10 is a configuration diagram of an electric motor drive device 2 according to a fifth embodiment. This shows the relationship between currents on the γδ axis and the dq axis. FIG. 10 is a configuration diagram of an electric motor drive device 2 according to a sixth embodiment. 3 is a configuration example of an output voltage vector calculation means 13. 3 is a configuration example of an inverter main circuit 5. FIG. 10 is a configuration diagram of an electric motor drive device 2 according to a seventh embodiment. The correction of dead time error will be described. FIG. 10 is a configuration diagram of an electric motor drive device 2 according to an eighth embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 DC power supply, 2 Motor drive device, 5 Inverter main circuit, 6 Current detection means, 7 DC voltage detection means, 8 Inverter control means, 9 Coordinate conversion means, 10 Torque calculation means, 11 Rotation speed control means, 12 Applied voltage Control means, 13 Output voltage vector calculation means, 14 Voltage / phase command calculation means, 15 Drive signal generation means, 16 PI controller, 17 Torque command storage means, 18 Proportional control gain, 19 Integral control gain, 20 Integral with limiter , 21 limiter, 22 axis error calculation means, 23 coordinate conversion correction means, 24 output voltage vector calculation machine, 25 proportional controller, 26 integrator, 27 switching element, 28 freewheeling diode, 29 dead time correction means, 30 voltage Error estimation means, 31 voltage detection means, 32 rotation detection means.

Claims (40)

An inverter for applying a voltage to the motor;
Voltage detecting means for detecting a voltage applied by the inverter to the electric motor;
Current detecting means for detecting a current flowing through the motor;
Control means for controlling a voltage applied to the electric motor by the inverter;
With
The control means includes
Coordinate conversion means for converting the outputs of the current detection means and the voltage detection means into an orthogonal biaxial coordinate system;
A rotational speed estimating means for estimating the rotational speed of the electric motor based on an output from the coordinate converting means;
And torque calculating means for obtaining by calculation the torque of the motor based on the output of the previous SL coordinate transformation hand stage and the rotation speed estimation means,
A rotation speed control means for controlling the rotation speed of the electric motor based on the calculated value obtained by the torque calculation means;
An electric motor drive device comprising: An inverter for applying a voltage to the motor;
Voltage detecting means for detecting a voltage applied by the inverter to the electric motor;
Current detecting means for detecting a current flowing through the motor;
Rotation detection means for detecting the rotation speed or rotation position of the electric motor;
Control means for controlling a voltage applied to the electric motor by the inverter;
With
The control means includes
Coordinate conversion means for converting the outputs of the current detection means and the voltage detection means into an orthogonal biaxial coordinate system;
And torque calculating means for obtaining by calculation the torque of the motor based on the output of the previous SL coordinate transformation hand stage and the rotation detecting means,
A rotation speed control means for controlling the rotation speed of the electric motor based on the calculated value obtained by the torque calculation means;
An electric motor drive device comprising: The control means includes
An axis error calculation means for calculating an axis error between the γδ axis based on the estimated direction of the magnetic flux generated by the field of the motor and the dq axis based on the direction of the magnetic flux generated by the field of the motor;
Coordinate conversion correction means for correcting the output of the coordinate conversion means based on the output from the axis error calculation means;
With
The torque calculation means includes
The torque of the electric motor is obtained by calculation based on the output of the coordinate conversion correction means.
The electric motor drive device according to claim 1, wherein the electric motor drive device is an electric motor. The control means includes
The motor drive device according to claim 3 , wherein the voltage applied to the motor by the inverter is controlled so that the δ-axis magnetic flux is zero and the γ-axis magnetic flux is equal to an induced voltage constant of the motor. . The control means includes
Axis error calculation means for calculating an axis error between the γδ axis based on the estimated direction of the magnetic flux generated by the electric field of the motor and the dq axis based on the direction of the magnetic flux generated by the electric field of the electric motor,
The voltage applied to the electric motor by the inverter is controlled so that the axial error between the dq axis and the γδ axis becomes zero.
The electric motor drive device according to claim 1, wherein the electric motor drive device is an electric motor. The control means includes
The electric motor according to any one of claims 1 to 5 , further comprising dead time correction means for correcting an error generated in a voltage applied to the electric motor due to a dead time of a switching element included in the inverter. Drive device. The torque calculation means includes
Current flowing in the motor on the dq axis with reference to the direction of magnetic flux generated by the field of the motor,
Voltage applied to the motor on the dq axis,
The rotational speed of the motor,
Winding resistance,
Number of poles,
The motor drive device according to any one of claims 1 to 6 , wherein the torque of the electric motor is obtained by calculation using a motor. The torque calculation means includes
At least one of a current flowing through the motor on the dq axis or a voltage applied to the motor on the dq axis,
The electric motor drive device according to claim 7 , wherein the torque of the electric motor is calculated by replacing it with a value on a γδ axis based on an estimated direction of a magnetic flux generated by the field of the electric motor. The torque calculation means includes
At least one of a current flowing through the motor, a voltage applied to the motor, or a rotational speed of the motor,
The motor drive device according to claim 7 or 8 , wherein the torque of the electric motor is obtained by calculation in place of these command values. The torque calculation means includes
Current flowing in the motor on the dq axis with reference to the direction of magnetic flux generated by the field of the motor,
Inductance of the motor on the dq axis,
Induced voltage constant of the motor,
Number of poles,
The motor drive device according to any one of claims 1 to 6 , wherein the torque of the electric motor is obtained by calculation using a motor. The torque calculation means includes
The current flowing through the motor on the dq axis is
The motor drive device according to claim 10 , wherein the torque of the motor is obtained by calculation by replacing with a value on the γδ axis based on an estimated direction of magnetic flux generated by the field of the motor. The torque calculation means includes
The current flowing through the motor,
The motor drive device according to claim 10 or 11 , wherein the torque of the electric motor is obtained by calculation instead of the command value. The torque calculation means includes
Q-axis current flowing in the motor on the dq axis with respect to the direction of magnetic flux generated by the field of the motor,
Induced voltage constant of the motor,
Number of poles,
The motor drive device according to any one of claims 1 to 6 , wherein the torque of the electric motor is obtained by calculation using a motor. The torque calculation means includes
Q-axis current flowing through the motor on the dq-axis,
The motor drive device according to claim 13 , wherein the torque of the motor is obtained by calculation by replacing it with a value on the γδ axis based on an estimated direction of magnetic flux generated by the field of the motor. The rotation speed control means includes
Based on the output of the torque calculation means, a torque command value of the motor, so as to keep a preset constant value, one of the claims 1 to 14, characterized in that to control the rotational speed of the electric motor A drive device for an electric motor according to claim 1. The rotation speed control means includes
When the output of the torque calculation means becomes larger than a preset torque command value, the rotational speed of the electric motor is reduced,
The motor drive device according to any one of claims 1 to 14 , wherein when the torque command value becomes smaller than a preset value, the original rotational speed is restored. The rotation speed control means includes
The motor drive according to any one of claims 1 to 14 , wherein when the rotational speed of the electric motor reaches a preset lower limit value, the rotational speed is not further reduced. apparatus. The rotation speed control means includes
The rotation speed of the electric motor is increased within a preset upper limit value of the rotation speed when the output of the torque calculation means is smaller than a preset torque command value. 14. The drive device for an electric motor according to any one of 14 above. The rotation speed control means includes
The torque command value is
Induced voltage constant of the motor,
Number of poles,
The γδ axis based on the estimated direction of the d axis current flowing through the motor on the dq axis, the d axis current command value, or the magnetic field generated by the field of the motor on the dq axis with respect to the direction of the magnetic flux generated by the field of the motor Γ-axis current flowing through the motor above,
Overcurrent breaking current,
The motor driving device according to any one of claims 15 to 18 , wherein the motor driving device is obtained using the following equation. The rotation speed control means includes
The electric motor according to any one of claims 1 to 19, characterized in that to control the rotational speed of the motor to avoid the rotational speed range set by the mechanical properties of the load connected to the electric motor Drive device. The motor drive device according to any one of claims 1 to 20 , further comprising abnormality detection means for detecting a torque abnormality of the electric motor based on a calculation value obtained by the torque calculation means. The abnormality detection means includes
The electric motor drive device according to claim 21 , wherein when an abnormality is detected, an electric signal is issued and notified by an alarm or a display. The motor drive device according to claim 21 or 22 , wherein the abnormality detection unit stops the operation of the electric motor when an abnormality is detected. An air conditioner comprising the electric motor drive device according to any one of claims 1 to 23 . An air conditioner comprising the electric motor drive device according to any one of claims 21 to 23 ,
The abnormality detection means includes
By detecting an increase in torque of the motor,
An air conditioner that detects clogging due to frost formation or the like of an outdoor heat exchanger of the air conditioner. The abnormality detection means includes
When clogging due to frost or the like of the outdoor heat exchanger of the air conditioner is detected,
The air conditioner according to claim 25 , wherein a signal indicating that the outdoor heat exchanger should be defrosted is output. An air conditioner comprising the electric motor drive device according to any one of claims 21 to 23 ,
The abnormality detection means includes
By detecting an increase in torque of the motor,
An air conditioner that detects clogging of a filter of the air conditioner. The abnormality detection means includes
When clogging of the air conditioner filter is detected,
The air conditioner according to claim 27 , wherein a signal indicating that the filter should be cleaned is output. A washing machine comprising the electric motor drive device according to any one of claims 1 to 23 . A washing machine comprising the electric motor drive device according to any one of claims 21 to 23 ,
The abnormality detection means includes
By detecting an increase in torque of the motor,
A washing machine characterized by detecting clogging of a filter of the washing machine. The abnormality detection means includes
When clogging of the filter of the washing machine is detected,
The washing machine according to claim 30 , wherein a signal indicating that the filter should be cleaned is output. A washing and drying machine comprising the electric motor drive device according to any one of claims 1 to 23 . A washing / drying machine comprising the electric motor drive device according to any one of claims 21 to 23 ,
The abnormality detection means includes
By detecting an increase in torque of the motor,
A washing / drying machine that detects clogging of a filter of the washing / drying machine. The abnormality detection means includes
When clogging of the filter of the washing dryer is detected,
The washing / drying machine according to claim 33 , wherein a signal indicating that the filter should be cleaned is output. A refrigerator comprising the electric motor drive device according to any one of claims 1 to 23 . 24. A ventilation fan comprising the electric motor drive device according to any one of claims 1 to 23 . A ventilation fan comprising the electric motor drive device according to any one of claims 21 to 23 ,
The abnormality detection means includes
By detecting an increase in torque of the motor,
A ventilation fan characterized by detecting clogging of a filter of the ventilation fan. The abnormality detection means includes
When clogging of the filter of the ventilation fan is detected,
The ventilation fan according to claim 37 , wherein a signal indicating that the filter should be cleaned is output. A heat pump water heater comprising the electric motor drive device according to any one of claims 1 to 23 . A heat pump water heater comprising the electric motor drive device according to any one of claims 21 to 23 ,
The abnormality detection means includes
By detecting an increase in torque of the motor,
A heat pump water heater that detects clogging caused by foreign matter in the pump.

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