JP2005171843A - Fan control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fan control device, for surely starting the fan even if the fan has already been rotated by an external force before start-up. <P>SOLUTION: Resistors 14, 15, 16 detect winding current of an electric motor 4M for driving the fan, and a rotor speed estimation/calculation means 25 estimates the number of rotations of the electric motor based on voltage command value supplied to the electric motor and winding current. Calculation parts 29-34 calculate a torque component and an exciting component of the voltage command value so as to match the estimated rotation number of the electric motor and a preset target rotation number. When a waveform generation means 35 generates a driving waveform signal for driving a power conversion part 13, a rotation number detection command part 40 operates the power conversion part 13 before the start-up to make the rotor speed estimation/calculation means 25 estimate the rotation number of the electric motor, and start-up control means 21, 22 divide a predetermined low-speed range into a plurality of sections and set at least one of the target rotation number and the exciting component of the voltage command value to be a value unique to the start-up for each section so as to perform start-up control. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fan control device that detects a winding current of an electric motor and performs vector control of the electric motor for driving the fan.

  Even when the outdoor fan of the air conditioner is not driven, the outdoor fan rotates freely by the outdoor wind. By performing energization to stop the motor while detecting the position and rotation speed of the rotor made of a permanent magnet using a Hall element to detect the rotation state of the drive motor during the reverse rotation of this outdoor fan, There has been proposed one in which activation control is executed after the electric motor is temporarily stopped (see, for example, Patent Document 1).

On the other hand, in recent electric motor drives, a method has been adopted in which a sensor such as a Hall element that detects the number of revolutions is eliminated, the number of parts is reduced, reliability deterioration due to part failure is suppressed, and costs are reduced. . For example, when this method is applied to an electric motor drive device constituting a refrigeration cycle, the current flowing through the windings for two phases or three phases is detected, and the rotational speed is calculated from the current value. Vector control that drives by estimating also (for example, refer to Patent Document 2).
JP 2000-125854 A JP 2002-95282 A

  As is well known, the compressor driving motor of an air conditioner has a single direction of rotation and does not reversely rotate due to outdoor wind, so start-up control based on the detected current value flowing in the motor windings Is relatively easy. However, in the configuration in which the number of revolutions is calculated from the detected current value flowing in the motor winding, it is difficult to detect the position of the motor rotating by the outdoor wind, so that a braking torque corresponding to the rotor position is applied to stop the rotor. However, if appropriate energization is performed, the motor will step out, and an overcurrent will flow through the switching elements constituting the inverter, resulting in an abnormal stop, eventually failing to start normally. In addition, when the fan is rotating at a low speed, the number of rotations cannot be accurately read.

  The present invention has been made to solve the above-described problems, and its purpose is to estimate the rotor position based on the detected value of the winding current of the motor driving the fan and perform speed control before starting. Another object of the present invention is to provide a fan control device that can be reliably started even when the fan is rotating by an external force.

  According to the first aspect of the present invention, there is provided a power converter that converts direct current into alternating current and supplies the fan drive motor, current detection means for detecting a winding current of the motor, and a torque component of a voltage command value supplied to the motor. And a rotor speed estimation calculating means for estimating the rotation speed of the motor based on the excitation component and the detected winding current, and a voltage command so that the estimated rotation speed of the motor matches a preset target rotation speed. A waveform for generating a drive waveform signal for driving the power conversion unit based on the torque component and excitation component of the voltage command value, and the estimated rotation speed of the motor A generating means, a power converter before starting and a rotor speed estimating calculating means for estimating the rotational speed of the electric motor, and a rotational speed of the electric motor estimated before starting is a predetermined value. When in the speed range, this low speed range is divided into a plurality of sections, and at each section, at least one of the excitation component of the target rotation speed and voltage command value is set to a specific value at start-up and start control is executed. And a fan control device.

  According to a fifth aspect of the present invention, there is provided a power converter that converts direct current into alternating current and supplies the fan drive motor, current detection means for detecting a winding current of the motor, and a torque component of a voltage command value supplied to the motor. And a rotor speed estimation calculating means for estimating the rotation speed of the motor based on the excitation component and the detected winding current, and a voltage command so that the estimated rotation speed of the motor matches a preset target rotation speed. A waveform for generating a drive waveform signal for driving the power conversion unit based on the torque component and excitation component of the voltage command value, and the estimated rotation speed of the motor A generating means, a power converter before starting and a rotor speed estimating calculating means for estimating the rotational speed of the electric motor, and a rotational speed of the electric motor estimated before starting is a predetermined value. When the rotational speed is in the reverse direction and the rotational speed belongs to the lower limit of the low speed range, the excitation component of the target rotational speed and voltage command value is included so as to include deceleration control that brings the rotational speed of the motor closer to zero. A fan control device comprising start control means for executing start control by setting at least one of them to a specific value at the time of start.

  According to the present invention configured as described above, a fan control device that can be reliably started even when the fan is rotated by an external force before the start is provided.

  Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of a main part of an outdoor unit of an air conditioner (hereinafter also simply referred to as an air conditioner) to which the present invention is applied. In the figure, an outdoor unit 1 of an air conditioner is arranged with an outdoor heat exchanger 2 bent at a substantially right angle on the left side and the back as viewed from the front (from the bottom to the top of the drawing), and a compressor on the right side. 3 is installed, and an outdoor fan 4 for driving a fan 4F by a fan drive motor 4M is mounted inside the outdoor heat exchanger 2, and the outdoor air is sucked in from the A and B arrow directions and discharged in the C arrow direction. The heat exchanger 2 is configured to promote heat exchange.

  FIG. 2 is a circuit diagram partially showing in block form the configuration of the first embodiment of the fan control device for controlling the outdoor fan 4. This fan control device mainly includes an inverter main circuit 10 and a motor control unit 20A. Among these, in the inverter main circuit 10, the smoothing capacitor 12 and the power conversion unit 13 are connected in parallel between the positive and negative output terminals of the DC power supply unit 11. The power converter 13 is a three-phase bridge connection of six switching elements connected in reverse parallel to the return diode, and is an interconnection point between the positive side switching element and the negative side switching element, that is, 3 The phase winding of the fan drive motor 4M is connected to the output terminal of the phase AC voltage. Further, resistors 14, 15, and 16 are respectively connected between the negative side of the DC power supply unit 11 and the negative side arm for the three phases of the power conversion unit 13, and the DC voltage detection unit 17 is parallel to the smoothing capacitor 12. The motor control unit 20A is connected to the power conversion unit 13 on the basis of a current detection value generated as a voltage in the resistors 14, 15 and 16 and a DC voltage detection value detected by the DC voltage detection unit 17. The on / off control of the switching elements that constitute the circuit is performed.

  Next, a detailed configuration of the motor control unit 20A will be described. The motor control unit 20A includes a target rotation number setting unit 21 that outputs a start / stop command based on the estimated rotation number ωest of the rotor and outputs a target rotation number ωref2 having a different size as time elapses. I have. A target rotational speed selection unit 22 is connected to the target rotational speed setting unit 21. The target rotational speed selection unit 22 receives a target rotational speed ωref1 from the outside and a start / stop command of the target rotational speed setting unit 21 or a target rotational speed ωref2 of the startup control, and among these, the target rotational speed ωref2 during the startup control And outputting a target rotational speed ωref1 during normal control, and a function of temporarily stopping the output operation when a rotational speed detection command X, which will be described later, is given. Connected to the target rotational speed selection unit 22 is a subtracter 23 whose output is a subtracted input and whose estimated rotational speed ωest of the rotor is a subtracted input. The target rotational speed setting unit 21 and the target rotational speed selection unit 22 constitute the start control means of the present invention.

  On the other hand, torque component current Iq and excitation component current converted into coordinates on the rotor shaft based on current detection values converted into voltages by resistors 14, 15 and 16, respectively, and a rotor estimated position θest of an electric motor to be described later. A current detection unit 24 for calculating Id is provided. A rotor speed estimation calculation unit 25 is connected to the current detection unit 24. The rotor speed estimation calculation unit 25 includes a DC voltage detected by the DC voltage detection unit 17, a torque component current Iq and an excitation component current Id calculated by the current detection unit 24, and a d-axis component Vd of a voltage command value described later. And the estimated rotational speed ωest1 of the rotor based on the q-axis component Vq.

  When the estimated rotational speed ωest1 enters a predetermined range (for example, −100 rpm to +60 rpm) in the output path of the rotor speed estimation calculation unit 25, the current rotational speed is estimated from the previous rotational speed and the estimated rotational speed is estimated. The rotor speed estimation control unit 27 that outputs the number ωest2 and the estimated rotation speed ωest2 of the rotor speed estimation control unit 27 in place of the estimated rotation speed ωest1 of the rotor speed estimation calculation unit 25 within a range where the estimated rotation speed ωest1 is less than a certain value. Is connected to a speed selecting unit 26 that outputs the current estimated rotational speed ωest. The estimated rotational speed ωest output from the speed selecting unit 26 is added to the target rotational speed setting unit 21 and the subtractor 23 described above. Further, an integration unit 28 is connected to the output path of the speed selection unit 26. The integration unit 28 integrates the estimated rotational speed ωest and adds it to the current detection unit 24 and the waveform synthesis unit 35 as the estimated rotor position θest of the electric motor.

  Connected to the output terminal of the subtractor 23 is a PI control unit 29 that outputs a target value Iqref of the torque component current by proportionally integrating the output, that is, the difference between the target rotational speed ωref and the estimated rotational speed ωest. ing. The PI control unit 29 is connected to a subtractor 30 whose output is a subtracted input and the torque component current Iq is a subtraction input, and further, an arithmetic operation for converting the target value Iqref of the torque component current into the target value Idref of the excitation component current. The unit 31 is connected. The calculation unit 31 is connected to a subtracter 32 whose output is a subtracted input and whose excitation component current target value Idref is a subtraction input.

  A PI control unit 33 is connected to the subtracter 30, and the q-axis component Vq of the voltage command value is output by proportionally and integrating the difference between the target value Iqref of the torque component current and the torque component current Iq. A PI control unit 34 is connected to the subtractor 32, and the d-axis component Vd of the voltage command value is output by integrating the difference between the target value Idref of the excitation component current of the voltage command value and the excitation component current Id. Then, the q-axis component Vq and the d-axis component Vd of the voltage command value, the voltage detection value of the DC voltage detection unit 17 described above, and the estimated rotor position θest of the integration unit 28 are added to the waveform synthesis unit 35. Based on these inputs, the waveform synthesizer 35 calculates drive voltages Vu, Vv, Vw on the stator shaft of the fan drive motor 4M, and further drives the switching elements of the power converter 13 in accordance with the drive voltages. A drive waveform signal is generated.

  Further, in order to detect the rotational speed of the outdoor fan 4 rotating by an external force before performing the start control, the rotational speed detection command unit 40 that outputs the rotational speed detection command X for a short time is provided. The rotational speed detection command X is applied to the target rotational speed setting unit 21, the target rotational speed selection unit 22, the speed selection unit 26, and the waveform synthesis unit 35. Note that when the rotational speed detection command X is applied, the target rotational speed setting unit 21 and the target rotational speed selection unit 22 stop their output operations, and the speed selection unit 26 estimates output from the rotor speed estimation calculation unit 25. The rotational speed ωest1 is output as it is as the estimated rotational speed ωest, and the waveform synthesizer 35 uses the d-axis component Vd and the q-axis component Vq of the voltage command value set in advance, and the rotor speed estimation calculator 25 causes the fan drive motor 4M. The current necessary for estimating the number of rotations is passed through the power converter 13. Each function including the rotation speed detection command unit 40 corresponds to the pre-startup speed estimation means of the present invention.

  The operation of the first embodiment configured as described above will be described below. In the following description, when the rotation direction of the fan drive motor 4M is a normal direction, for example, when viewed from the front, the number of rotations is clockwise. Is represented as +, and in the reverse direction, for example, in the case of counterclockwise when viewed from the front, is represented as-. Further, the torque current Iq when the torque current is generated in the positive direction of the rotation direction is expressed as +, and the current that generates the torque in the reverse direction is expressed as-. Further, the excitation current Id that enhances the excitation of the fan drive motor 4M is expressed as +, and the excitation current that decreases is expressed as-.

  In the first embodiment shown in FIG. 2, as a control operation, first, the pre-startup control for detecting the rotation speed of the fan drive motor 4M is performed, and then the fan drive motor 4M is moved in the normal rotation direction to a predetermined rotation speed. The startup control is executed to increase the engine speed to the normal control, and the normal control is shifted from the predetermined number of revolutions. In order to facilitate understanding, the normal control will be described first.

  In the inverter main circuit 10, the voltage supplied from the DC power supply unit 11 is smoothed by the smoothing capacitor 12 and supplied to the power conversion unit 13. The power conversion unit 13 is driven by the motor control unit 20A, converts direct current into three-phase alternating current, and supplies it to the fan drive motor 4M. At this time, the voltage supplied to the power converter 13 is detected by the DC voltage detector 17, the winding current of the fan drive motor 4M flows through the resistors 14, 15, and 16, and the voltage corresponding to the current is detected by the current. Added to section 24. The current detection unit 24 converts the current for three phases into a torque component current Iq and an excitation component current Id represented by coordinates on the rotor axis in accordance with the estimated rotor position θest and outputs the torque component current Iq.

  At this time, in the motor controller 20A, the target rotational speed ωref1 applied from the outside is selected by the target rotational speed selector 22 and added to the subtracter 23 as the target rotational speed ωref. Then, the subtractor 23 calculates the difference between the target rotational speed ωref and the estimated rotational speed ωest as a feedback signal. Subsequently, this difference is proportionally and integratedly calculated by the PI control unit 29 and output as a target value Iqref of the torque component current. The target value Iqref of the torque component current is input to the calculation unit 31, where a predetermined calculation such as multiplication by a coefficient is performed, and the target value Iqref is converted to the target value Idref of the excitation component current.

  Next, the subtractor 30 calculates the difference between the target value Iqref of the torque component current and the torque component current Iq, and this difference is proportionally and integratedly calculated by the PI control unit 33 and output as the q-axis component Vq of the voltage command value. Is done. The subtractor 32 calculates the difference between the excitation component current target value Idref and the excitation component current Id, and the difference is proportionally and integratedly calculated by the PI control unit 34 and output as the d-axis component Vd of the voltage command value. The Then, the q-axis component Vq and the d-axis component Vd are added to the rotor speed estimation calculation unit 25 and the waveform synthesis unit 35.

  The waveform synthesizer 35 calculates drive voltages Vu, Vv, Vw on the stator shaft of the motor 4 based on the q-axis component Vq, the d-axis component Vd, the rotor estimated position θest, and the DC voltage Vdc of the voltage command value, A drive waveform signal for driving the switching element of the power converter 3 is generated in correspondence with the drive voltage.

  Here, the rotor speed estimation calculation unit 25 calculates the estimated rotational speed ωest1 of the motor from the winding current of the motor by the circuit equation of the motor. In this case, the circuit equation of the motor is expressed by the following equation.

Vd = (R + PLd) × Id−ω × Lq × Iq (1)
Vq = ω × Ld × Id + (R + PLq) × Iq + ω × φ (2)
However,
P: differential operator R: winding resistance Ld: d-axis inductance Lq: q-axis inductance ω: rotational speed φ: induced voltage coefficient.

  The speed selection unit 26 selects the estimated rotational speed ωest1 of the motor by the rotor speed estimation calculation unit 25 as the estimated rotational speed ωest and adds it to the subtractor 23 and the integration unit 28. The integrating unit 28 integrates the estimated rotational speed ωest to output it as the rotor estimated position θest of the electric motor, and adds it to the current detecting unit 24 and the waveform synthesizing unit 35.

  The normal control has been described above, but the pre-startup control for detecting the rotational speed of the fan drive motor 4M performed prior to these controls will be described below. The rotor speed estimation calculation unit 25 estimates ωest1 using the circuit equation on the rotor coordinates, that is, the equation (1) for excitation and the equation (2) for torque generation. When the rotational speed ω is small, The values of the second term on the right side of equation (1) and the first and third terms on the right side of equation (2) are small. Since the winding resistance of the motor is its own loss, it is designed as small as possible to increase efficiency. Further, since the excitation component current Id does not directly contribute to the driving of the electric motor, it is controlled to be a small value in order to improve the efficiency. Further, the torque component current Iq is a current that generates the torque of the electric motor, and when the rotational speed of the electric motor is low, the load is small and therefore becomes a small value. In particular, the torque component current Iq is zero because the control is performed with the torque being zero in the detection of the rotational speed at the time of startup.

  On the other hand, the error of the current detector 24 includes a component proportional to the detected value (amplifier circuit gain error, etc.) and a component that does not depend on the detected value (offset voltage, etc.). Therefore, the relative error becomes large.

  In the first embodiment, since the rotational speed ω is estimated from the current value, the larger the current value error, the larger the rotational speed error. For this reason, in the rotation speed detection at the time of activation, the rotation speed cannot be accurately detected when the rotation speed is low. Further, since the rotor position θ is estimated based on the rotational speed ω, a large error also occurs in the estimated position of the rotor. In the vector control, the motor is rotated by applying a voltage corresponding to the position of the rotor. Therefore, if the estimation error of the rotor position increases, the motor cannot be smoothly performed.

  Therefore, in the present embodiment, the rotation speed detection command unit 40 is provided, and the rotation speed detection command X is output for a short period of time so as not to affect the rotation of the fan drive motor 4M. This is added to the rotation speed selection unit 22, the waveform synthesis unit 35, and the speed selection unit 26. At this time, the target rotation speed setting unit 21 and the target rotation speed selection unit 22 stop their operations, and the speed selection unit 26 uses the estimated rotation speed ωest1 of the rotor speed estimation calculation unit 25 as it is as the current estimated rotation speed ωest as an integration unit. In addition to 28, the waveform synthesizer 35 generates an energized waveform corresponding to the q-axis component Vq and the d-axis component Vd of the predetermined voltage command value, and drives the power converter 13. As a result, a current corresponding to the rotation of the fan drive motor 4M flows through the resistors 14, 15, and 16, and the current detection unit 24 calculates the torque component current Iq and the excitation component current Id converted into coordinates on the rotor shaft. The rotor speed estimation calculation unit 25 estimates the rotor speed based on the current value and the q-axis component Vq and the d-axis component Vd of the voltage command value and outputs the estimated rotational speed ωest1. Therefore, when the rotation speed detection command unit 40 outputs the rotation speed command X, the rotation speed detection before the start control is performed.

  Next, activation control according to the rotation speed before activation will be described. The target rotational speed setting unit 21 determines which of the following ranges (a) to (f) is the rotational speed due to the external wind.

(A) +400 rpm or more (b) +200 rpm to +400 rpm
(C) +80 rpm to +200 rpm
(D) -100 to +80 rpm
(E) -400 to -100 rpm
(F) −400 rpm or less The target rotational speed setting unit 21 outputs a start / stop command according to the determination result, or outputs a target rotational speed ωref2 whose magnitude increases at a predetermined rate as time elapses. Hereinafter, the operation of the target rotation speed setting unit 21 in each of the cases (a) to (f) will be described with reference to the chart shown in FIG.

In the case of (a) or (f): Since the influence of the external wind is too great to control the fan drive motor 4M, a start prohibition command is output. Then, after a predetermined time has elapsed, a rotation speed detection command is output to the rotation speed detection command unit 40. When it is confirmed that the absolute value of the rotational speed has dropped below 400 rpm, the following control is executed.

In the case of (b): A signal indicating that the rotational speed is +200 rpm or more is added to the target rotational speed selection unit 22. In response to this, the target rotational speed selection unit 22 selects an external target rotational speed ωref1 and outputs it as the target rotational speed ωref. Therefore, the process shifts to normal control without performing special start-up control.

In the case of (c): Since the detected rotational speed is in a normal direction and is too small to shift to normal control, the target rotational speed ωref2 increases to +200 rpm at a predetermined rate on the basis of the detected rotational speed. Is output, and when it reaches +200 rpm, a signal indicating that the rotational speed is +200 rpm or more is added to the target rotational speed selection unit 22. In response to this, the target rotational speed selection unit 22 first outputs the target rotational speed ωref2 as the target rotational speed ωref, and when a signal indicating that the rotational speed is +200 rpm or more is applied, an external target rotational speed ωref1 Is output as the target rotational speed ωref. Accordingly, when the rotational speed reaches +200 rpm, the start control is stopped and the normal control is started.

In the case of (d): 0 rpm is included inside, and it rotates at an ultra-low speed. In this state, the external force is also weak, so that the abnormal stop does not occur by increasing the rotation speed after stopping or controlling the rotation speed close thereto. Therefore, the target rotational speed setting unit 21 fixes the target rotational speed ωref2 to 0 rpm for 1 second as the reference rotational speed, and then outputs the target rotational speed ωref2 that increases to +200 rpm at a predetermined rate, and reaches +200 rpm. At this time, a signal indicating that the rotational speed is +200 rpm or more is added to the target rotational speed selection unit 22, and the routine proceeds to normal control in the same manner as in (c).

In the case of (e): When the detected rotational speed is lower than that in the case of (d), the target rotational speed ωref2 that increases up to +200 rpm at a predetermined rate on the basis of the detected rotational speed is output. When +200 rpm is reached, a signal indicating that the rotational speed is +200 rpm or more is added to the target rotational speed selection unit 22 and the routine proceeds to normal control in the same manner as in (c).

  By the way, in the control of (e) above, when the speed of the reversely rotating electric motor is gradually brought close to 0 to 0 and then rotated in the normal direction to increase the rotational speed, the rotational speed is 0. The estimated rotational speed ωest1 output from the rotor speed estimation calculation unit 25 becomes unstable in the vicinity of. Therefore, when the pre-startup control is finished, the speed selection unit 26 is restored so as to operate normally. As a result, as shown in FIG. 4A, until the rotational speed ω is changed from −100 rpm to +60 rpm, the rotor speed estimation control unit 27 is based on the temporal change rate of the previous rotational speed ω (<−100 rpm). The rotational speed ω at the next time point is estimated, and the estimated rotational speed ωest2 is output. The speed selection unit 26 outputs the estimated rotational speed ωest2 as the estimated rotational speed ωest instead of the estimated rotational speed ωest1 in these rotational speed ranges. During this time, the target value Iqref of the torque component current output from the PI control unit 29 is kept constant.

  When the rotational speed before startup is in any of the ranges (c), (d), and (e), the control shifts to normal control when the detected rotational speed value reaches +200 rpm, but instead torque current Even if the control shifts to the normal control when the component Iq reaches a constant value corresponding to +200 rpm, the same control as described above can be performed.

  Thus, according to the first embodiment, when the rotation speed of the fan drive motor 4M estimated before the start is in a predetermined low speed range, that is, in the range of −400 rpm to +200 rpm, the low speed range is divided into a plurality of sections. Since the target rotation speed is set to a specific value at the time of startup for each section and the startup control is executed, when the rotor position is estimated based on the detected value of the winding current of the motor driving the fan, the speed control is performed. Even if the fan is rotating by external force before starting, it can be started reliably.

  FIG. 5 is a circuit diagram partially showing in block form the configuration of Embodiment 2 of the fan control device according to the present invention. In the figure, the same elements as those in FIG. 2 showing the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the motor control unit 20B shown here, the estimated rotational speed ωest of the motor estimated by the rotor speed estimation calculation unit 25 or the rotor speed estimation control unit 27 and output from the speed selection unit 26 is within a predetermined range, for example, −100 rpm The excitation correction control unit 36 that outputs the excitation component current correction value ΔIdref in the range of +60 rpm or −60 rpm to +60, and the excitation component current correction value ΔIdref output from the excitation correction control unit 36 In addition to the output, when the error of the adder 37 used as the subtracted input of the subtractor 32 and the estimated rotational speed ωest1 by the rotor speed estimation calculation unit 25 is large, that is, the speed selection unit 26 estimates the rotor speed estimation control unit 27. When the rotational speed ωest2 is selected, the current torque is calculated from the change state of the target value Iqref1 of the torque component current before being output from the PI control unit 29. Torque component current target value setting unit 39 that estimates the target value Iqref of the torque component current and outputs the set value Iqref2 of the torque current component, and PI control when the speed selection unit 26 selects the output of the rotor speed estimation control unit 27 Instead of the torque component current target value Iqref1 of the unit 29, the torque component current target value Iqref2 of the torque component current target value setting unit 39 is selected and used as the current torque component current target value Iqref. The point that the torque component current target value selection unit 38 to be added as a subtraction input is provided is different from the first embodiment, and the other configuration is the same as the first embodiment.

  The operation of the second embodiment configured as described above will be described below with reference to FIGS. 6 and 7, particularly focusing on differences from the first embodiment. As described above, since the excitation component current Id does not directly contribute to the driving of the electric motor, it is controlled to be a small value in order to improve the efficiency. In the second embodiment, when the rotation speed of the motor estimated by the pre-startup control is in the range of (d) described above, the excitation correction control unit 36 is operated until it reaches +60 rpm to correct the excitation component current correction value. ΔIdref is added to the output of the calculation unit 31 to increase the d-axis component Vd of the voltage command value, and when the rotation speed of the motor estimated by the pre-startup control is in the range of (e) described above, −60 rpm The excitation correction control unit 36 is operated in a range of ˜ + 60 rpm, and the correction value ΔIdref of the excitation component current is added to the output of the calculation unit 31 to increase the d-axis component Vd of the voltage command value. FIG. 5 is a chart corresponding to FIG. 3 to which these controls are added, and FIG. 7 is a diagram corresponding to FIG. 4 showing the increase of the d-axis component Vd in FIG. In this case, the correction value ΔIdref of the excitation component current is increased at a constant change rate from −100 rpm to −60 rpm for t1 time, and further decreased from +60 rpm to +80 rpm at a constant change rate for t2 time to stabilize the control. Ensure sex. As a result, stable control can be performed in both the forward and reverse low-speed rotation ranges including zero rotation.

  On the other hand, the torque component current target value setting unit 39 monitors the target value Iqref1 of the current torque component current output from the PI control unit 29, and estimates the target value Iqref of the subsequent torque component current based on the result. The torque current component set value Iqref2 is output. When the speed selection unit 26 selects the estimated rotational speed ωest2 of the rotor speed estimation control unit 27 and outputs it as the estimated rotational speed ωest, the torque component current target value selection unit 38 outputs the estimated rotational speed ωest. Instead of the torque component current target value Iqref1, the torque component current target value setting unit 39 selects the torque component current setting value Iqref2 and adds it to the subtractor 30 as the current torque component current target value Iqref. Further, when the speed selection unit 26 selects the estimated rotational speed ωest1 of the rotor speed estimation calculation unit 25, the selection of the torque current component set value Iqref2 of the torque component current target value setting unit 39 is stopped and the PI control unit 29 Torque current component target value Iqref1 is selected and output as torque current component target value Iqref.

  As a result, the target value Iqref of the torque current component is stabilized and fluctuations in the generated torque can be suppressed. Therefore, the accuracy when the estimated rotational speed ωest2 is used as the estimated rotational speed ωest is improved, and the motor is stably controlled. be able to. Further, since the torque component current as large as possible can be set until the rotation direction of the motor becomes a normal direction, the effect that the rotation speed of the motor can reach the target rotation speed ωref in a short time can also be obtained. .

  Thus, according to the second embodiment, when the rotation speed of the fan drive motor 4M estimated before the start is in a predetermined low speed range, that is, in the range of −400 rpm to +200 rpm, the low speed range is divided into a plurality of sections. Since the target rotation speed is set to a specific value at the time of startup for each section and the startup control is executed, when the rotor position is estimated based on the detected value of the winding current of the motor driving the fan, the speed control is performed. Even if the fan is rotating by external force before starting, it can be started reliably. Further, by adding the excitation correction control unit 36, it is possible to control more stably at both the forward and reverse low speeds including zero rotation, and further, the torque component current target value selection unit 38 and the torque component current target By adding the value setting unit 39, an effect that the rotational speed of the electric motor can reach the target rotational speed ωref in a short time can be obtained.

  In each of the above embodiments, a resistor is connected in series with each negative arm of the power converter 13 to detect the current flowing in the winding of the motor. Instead, for example, the smoothing capacitor 12 and the power converter It is also possible to detect the current flowing in the winding of the motor by connecting a resistor to one current path between the power converter 13 and measuring the voltage at both ends at the timing when each switching element of the power converter 13 is turned on. .

The cross-sectional view which shows the structure of the principal part of the outdoor unit of the air conditioner to which this invention is applied. BRIEF DESCRIPTION OF THE DRAWINGS The circuit diagram which showed the structure of Example 1 of the fan control apparatus which concerns on this invention partially in the block. The figure which showed the various control forms corresponding to the rotation speed before starting in order to demonstrate operation | movement of Example 1. FIG. FIG. 3 is a time chart showing the relationship between the estimated rotational speed of the electric motor and a target value of torque component current in order to explain the operation of the first embodiment. The circuit diagram which partially showed the structure of Example 2 of the fan control apparatus based on this invention in the block. The figure which showed the various control forms corresponding to the rotation speed before starting in order to demonstrate operation | movement of Example 2. FIG. FIG. 3 is a time chart showing the relationship between an estimated rotation speed of the motor, a target value of torque component current, and an increase in excitation component current in order to explain the operation of Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outdoor unit of an air conditioner 4 Outdoor fan 11 DC power supply part 13 Power conversion parts 14, 15, 16 Resistance 17 DC voltage detection part 17
20A, 20B Motor control unit 21 Target rotation number setting unit 22 Target rotation number selection unit 24 Current detection unit 24
25 Rotor speed estimation calculation unit 26 Speed selection unit 27 Rotor speed estimation control unit 28 Integration unit 35 Waveform synthesis unit 36 Excitation correction control unit 38 Torque component current target value selection unit 39 Torque component current target value setting unit 40 Rotation speed detection command unit

Claims (5)

A power converter that converts direct current to alternating current and supplies it to the fan drive motor;
Current detection means for detecting the winding current of the motor;
Rotor speed estimation calculation means for estimating the rotational speed of the motor based on the torque component and excitation component of the voltage command value supplied to the motor, and the detected winding current;
A calculation unit that calculates a torque component and an excitation component of the voltage command value so that the estimated rotation number of the electric motor matches a preset target rotation number;
Waveform generation means for generating a drive waveform signal for driving the power converter based on the torque component and the excitation component of the voltage command value and the estimated rotation speed of the motor;
Pre-starting speed estimation means for starting the power converter before starting and causing the rotor speed estimation calculating means to estimate the number of revolutions of the motor;
When the rotation speed of the motor estimated before starting is in a predetermined low speed range, the low speed range is divided into a plurality of sections, and at least one of the target rotation speed and the excitation component of the voltage command value is divided for each section. Start control means for setting a specific value at start and executing start control;
Fan control device with   The activation control means sets the target rotation speed to 0 or a value close to the target rotation speed for a predetermined time when the rotation speed of the motor estimated by the rotor speed estimation calculation means before starting is in a first section including 0. 2. The fan control device according to claim 1, wherein the fan control device is set and increases the target rotational speed in an upper limit direction of a low speed range after a predetermined time has elapsed, and increases an excitation component of the voltage command value.   The activation control means is configured to estimate the target rotation speed when the rotation speed of the motor estimated by the rotor speed estimation calculation means before activation is in a second section larger in the reverse rotation direction than the first section. The fan control device according to claim 1, wherein the fan control device increases the rotational speed in the upper limit direction of the low speed range.   The start control means is configured such that the rotational speed of the electric motor estimated by the rotor speed estimation calculation means reaches the upper limit of the low speed range, or the torque component current of the current value detected by the current detection means is the low speed range. The fan control device according to any one of claims 1 to 3, wherein the start control is stopped when a value corresponding to an upper limit of the value is reached. A power converter that converts direct current to alternating current and supplies it to the fan drive motor;
Current detection means for detecting the winding current of the motor;
Rotor speed estimation calculation means for estimating the rotational speed of the motor based on the torque component and excitation component of the voltage command value supplied to the motor, and the detected winding current;
A calculation unit that calculates a torque component and an excitation component of the voltage command value so that the estimated rotation number of the electric motor matches a preset target rotation number;
Waveform generation means for generating a drive waveform signal for driving the power converter based on the torque component and the excitation component of the voltage command value and the estimated rotation speed of the motor;
Pre-starting speed estimation means for starting the power converter before starting and causing the rotor speed estimation calculating means to estimate the number of revolutions of the motor;
When the rotational speed of the electric motor estimated before start-up is in a predetermined low speed range, and when the rotational speed is in the reverse direction and the rotational speed belongs to the lower limit part of the low speed range, deceleration control is performed to bring the rotational speed of the motor close to zero. A starting control means for setting the at least one of the target rotational speed and the excitation component of the voltage command value to a specific value at the time of starting to execute the starting control,
Fan control device with

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