JP2019161874A - Motor control device - Google Patents

Abstract

An object of the present invention is to provide a motor control device capable of accurately identifying a motor inductance of a permanent magnet synchronous motor and preventing an operation failure such as a decrease in operation responsiveness and a step-out. A first output current flowing through a permanent magnet synchronous motor by energizing by selecting switching elements of an inverter control unit one by one from an upper arm and a lower arm while the motor rotor is stopped at a predetermined position. The two motor inductances are identified from a vector and a second output current vector flowing through the permanent magnet synchronous motor 101 by energizing the inverter control unit 110 so as to be in a direction opposite to the first output current vector. The inductance identifying means 109 for calculating the average value sequentially integrates the output voltage of the inverter control unit 110 and divides the successively obtained integral value by the three-phase to two-phase conversion value of the phase current value output from the current sensor 102. I do. [Selection diagram] FIG.

Description

  The present invention relates to a motor controller for a permanent magnet synchronous motor, and more particularly to an automatic measurement technique for motor constants.

  The permanent magnet synchronous motor can improve the control performance and reduce power loss during operation by vector control. The voltage equation representing the relationship between the dq-axis current and the dq-axis voltage in vector control is constituted by the armature winding resistance, inductance, and induced voltage constant of the permanent magnet synchronous motor. In recent years, many sensorless systems have been adopted in which the position and speed of the armature are estimated using the dq-axis current and the dq-axis voltage without using the position sensor. In this method, since the position and speed of the armature are estimated based on the voltage equation, an error in the motor constant causes a significant decrease in responsiveness and step-out of the operation of the permanent magnet synchronous motor.

  In the conventional motor control, since a certain specification value is used as a motor constant, an error may occur with an actual motor constant. As one method for solving this, a technique has been proposed in which a motor constant is identified when the permanent magnet synchronous motor is stopped, and the identification result is reflected in the voltage equation.

  A typical technique for automatically measuring this type of permanent magnet synchronous motor constant is to automatically measure the armature winding resistance, d-axis inductance, q-axis inductance, and induced voltage constant of the permanent magnet synchronous motor during stoppage or operation. (For example, see Patent Document 1).

  Also, as one of the automatic d-axis inductance measurement methods for permanent magnet synchronous motor constants, a rectangular wave current for identification is superimposed on the d-axis current, and the difference in current amplitude per minute time is used to calculate the d-axis inductance. A method for identification is disclosed (for example, see Non-Patent Document 1).

JP 2008-182881 A

Morimoto Shigeo et al., “Position / Speed Sensorless Control System for Permanent Magnet Synchronous Motor with Parameter Identification Function”, D. 126, 6, pp. 748-755 (2006-6)

  However, the technique described in Non-Patent Document 1 is a method in which a rectangular wave current is used for the identification current signal when measuring the inductance when the motor is stopped. According to this method, when current samples are collected in synchronism before and after the transient change, the current difference value used in the inductance calculation formula becomes small, and there is a problem that the identification error increases. Therefore, in the technique described in Non-Patent Document 1, countermeasures against the above problem are taken by thinning out current sampling before and after a transient change.

In order to solve the above-described conventional problems, the motor control device of the present invention includes inverter control that has a switching element of three stones in the upper arm and three stones in the lower arm and drives a three-phase permanent magnet synchronous motor, While the motor rotor of the permanent magnet synchronous motor is stopped at a predetermined position, one stone or two stones are selected from the switching elements of the upper arm, and the bottom connected to the switching element not selected by the upper arm. By selecting and energizing at least one stone among the switching elements of the arm, the motor inductance 1 is identified from the first output current vector flowing in the permanent magnet synchronous motor, and the reverse of the first output current vector. By selecting a switching element from the upper arm and the lower arm and energizing the Inductance for identifying the motor inductance of the permanent magnet synchronous motor by identifying the motor inductance 2 from the second output current vector flowing in the permanent magnet synchronous motor and calculating the average value of the motor inductance 1 and the motor inductance 2 The inductance identification unit sequentially integrates the output voltage of the inverter control unit when identifying the motor inductance, and the successive integration value obtained thereby is obtained as the phase current value output from the current detection unit. It is configured to divide by the three-phase two-phase conversion value.

  As a result, the motor inductance can be accurately calculated from the small current region to the large current region, the calculation error can be reduced, and the operation responsiveness of the permanent magnet synchronous motor can be prevented from being deteriorated or malfunctioned. be able to.

  The motor control device according to the present invention determines the motor inductance when the motor inductance is identified by detecting the inductance current during the transient change in the inverter control in which the identification signal is superimposed when the motor rotor of the permanent magnet synchronous motor is stopped. It is possible to accurately identify from a small current region to a large current region, and it is possible to prevent the occurrence of operation troubles such as a decrease in operation responsiveness and a step-out of the permanent magnet synchronous motor.

Configuration diagram of a motor control device in Embodiment 1 of the present invention The detailed block diagram of the inverter control part of the motor control apparatus in Embodiment 1 of this invention The figure which shows the relationship between the UVW coordinate in the motor inductance identification of the motor control apparatus in Embodiment 1 of this invention, the position of a permanent magnet, and a dq coordinate. Explanatory drawing of the discretization calculation in motor inductance identification of the motor control apparatus in Embodiment 1 of this invention The figure which shows the relationship between the UVW coordinate, the position of a permanent magnet, and dq coordinate in the motor inductance identification of the motor control apparatus in Embodiment 2 of this invention.

According to a first aspect of the present invention, there is provided a current detection unit for detecting an armature current of a permanent magnet synchronous motor having a permanent magnet in a rotor, and rotation of the permanent magnet synchronous motor using a phase current value output from the current detection unit. A vector control unit for controlling the speed and output torque to predetermined values, and an inverter control unit for driving the three-phase permanent magnet synchronous motor having switching elements of three stones in the upper arm and three stones in the lower arm. In the motor control device, the vector control unit may select one or two of the switching elements of the upper arm in a state where the motor rotor of the permanent magnet synchronous motor is stopped at a predetermined position by current control of the armature current. At least one of the switching elements of the lower arm connected to the switching element not selected by the upper arm while being selected and energized By selecting and energizing, the motor inductance 1 of the permanent magnet synchronous motor is identified from the first output current vector flowing in the permanent magnet synchronous motor, and the direction is opposite to that of the first output current vector. In addition, by selecting a switching element from the upper arm and the lower arm and energizing, the motor inductance 2 of the permanent magnet synchronous motor is identified from the second output current vector flowing in the permanent magnet synchronous motor, and the motor Inductance identification means for identifying the motor inductance of the permanent magnet synchronous motor by calculating an average value of the inductance 1 and the motor inductance 2 is provided, and the inductance identification means controls the inverter control in identifying the motor inductance. Product of output voltage And a motor controller configured to divide a sequentially integrated values thereby obtained a three-phase two-phase converted value of the phase current value output from the current detector. With this configuration, the motor inductance can be identified with high accuracy from a small current region to a large current region, and it is possible to prevent the occurrence of operational troubles such as a decrease in operational responsiveness and a step-out of the permanent magnet synchronous motor.

  In a second aspect of the invention, in particular, in the motor control device of the first aspect of the invention, the inductance identifying means controls the first output current vector of the inverter control unit to be a current component parallel to the magnetic flux of the motor rotor. And the d-axis inductance of the permanent magnet synchronous motor is identified by controlling the second output current vector of the inverter control unit so as to be in the direction opposite to the first output current vector. Is done. With this configuration, the d-axis inductance of the permanent magnet synchronous motor can be identified with high accuracy from a small current region to a large current region.

  In a third aspect of the invention, in particular, in the motor control device of the first or second aspect of the invention, the inductance identifying means rotates the electrical angle by 90 degrees in any motor rotation direction from a predetermined position where the motor rotor is stopped. , Controlling the first output current vector of the inverter control unit to be a current component orthogonal to the magnetic flux of the motor rotor, and changing the second output current vector of the inverter control unit to the first output current vector. The q-axis inductance of the permanent magnet synchronous motor is identified by controlling so as to be in the opposite direction. With this configuration, the q-axis inductance of the permanent magnet synchronous motor can be identified with high accuracy from a small current region to a large current region.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a motor control device according to Embodiment 1 of the present invention. As shown in FIG. 1, the motor control device includes an inverter control unit 110 that drives the permanent magnet synchronous motor 101 as an inverter, and three currents that detect an armature current flowing in the three-phase winding of the permanent magnet synchronous motor 101. Sensors 102a, 102b, 102c (current detection unit), three-phase two-phase conversion means 103, motor rotor position / speed estimation means 104, two-phase three-phase conversion means 108, current control means 107, speed control means 106, inductance identification means 109 and a vector control unit (103 to 109) for controlling the rotation speed and output torque of the permanent magnet synchronous motor 101.

  FIG. 2 is a detailed configuration diagram of inverter control unit 110 of the motor control device according to Embodiment 1 of the present invention. As shown in FIG. 2, the inverter control unit 110 includes switching elements on the upper arm side and switching on the lower arm side configured by switching elements 111 to 116 such as IGBTs provided with free-wheeling diodes 121 to 126 in parallel. It has three phases of series circuit with elements. In the inverter control unit 110, the interconnection points of the upper arm and the lower arm in the three-phase series circuit are respectively connected to the three-phase windings of the permanent magnet synchronous motor 101 as a load. The two-phase / three-phase converter 108 outputs a pulse pattern signal for realizing the output voltage to the driver 131. Driver 131 outputs a signal for driving switching elements 111 to 116 in accordance with the drive signal.

  The inverter control unit 110 is a switching circuit that outputs three-phase AC voltages of U, V, and W. The inverter control unit 110 receives a drive signal from a control application such as a microcomputer connected to the gate of the switching element, and converts the applied DC voltage Vdc into a three-phase AC voltage by turning on and off the switching element in order. Then, the permanent magnet synchronous motor 101 to be controlled is driven. The microcomputer is equipped with a peripheral circuit for driving the inverter control unit 110, and the inverter control unit 110 includes three current sensors 102a and 102b by AD conversion means which is one of the peripheral circuits. , 102c is used to perform feedback control using the three-phase detection current obtained.

  In this embodiment, without using a position sensor such as a Hall element, the position and speed of the motor rotor are estimated using the current and voltage of the dq axis coordinates and the parameters of the permanent magnet synchronous motor 101, so-called sensorless. It is assumed that control is performed. The present invention can also be applied to vector control using a position sensor.

  In the field of sensorless vector control, it may be expressed as γδ axis, but in the following description of the present embodiment, the notation of dq axis and γδ axis is used without distinction. In addition, the current value is written in capital letter I or small letter i, and the voltage value is written in capital letter V or small letter v.

An outline of the operation of the vector control unit when the permanent magnet synchronous motor 101 is driven will be described. As shown in FIG. 1, current commands Id ^* and Iq ^{* on the} dq axis are created by the speed control means 106 based on information on the target rotational speed ω ^* given from the outside. Here, the field direction of the motor rotor is d-axis (field axis), and the direction orthogonal to the d-axis is q-axis.

The phase currents Iu, Iv, Iw obtained by the current sensors 102a, 102b, 102c are converted into detected currents Id, Iq on the dq coordinate by the three-phase / two-phase conversion means 103. Based on the deviation between the detected currents Id and Iq and the current commands Id ^* and Iq ^* , the current control means 107 creates voltage commands Vd ^* and Vq ^* . Based on the voltage commands Vd ^* and Vq ^* , the two-phase / three-phase converter 108 determines an output duty, and the inverter control unit 110 outputs a three-phase AC voltage based on the output duty to the permanent magnet synchronous motor 101. In this way, the permanent magnet synchronous motor 101 is controlled so that the actual rotational speed ω follows the target rotational speed ω ^* .

  Next, the operation of the inductance identification unit 109 will be described. The inductance identification process can be performed when a start command for the permanent magnet synchronous motor 101 is given. The permanent magnet synchronous motor 101 can be driven using the motor constant obtained in the identification process. The motor constant identified by this identification process is the d-axis inductance Ld.

  When the inductance identification process is started, first, in order to identify the motor constant while the motor rotor of the permanent magnet synchronous motor 101 is stationary, a positioning operation for pulling and fixing the motor rotor to a predetermined position is performed. FIG. 3 is a diagram showing the relationship between the U, V, W coordinates of the permanent magnet synchronous motor 101, the position of the motor rotor (permanent magnet), and the dq coordinates when the d-axis inductance Ld is identified in the first embodiment of the present invention. is there.

In order to position the motor rotor, a current command is given to the d-axis which is the field axis of the rotating coordinate system of the permanent magnet synchronous motor 101. A predetermined DC current command Id ^* is set as a current command to be applied, and a q-axis current command Iq ^* is set to zero. The q-axis current is set to zero so that no torque is generated. The speed control means 106 sets the current commands Id ^* and Iq ^* at this time.

When current commands Id ^* and Iq ^* are set so that a direct current of Ia for the U phase, -Ia / 2 for the V phase and -Ia / 2 for the W phase flows, the magnetomotive force due to the U phase current of the armature winding is used as a reference And can be treated as a reference position of θ = 0. Next, when current commands Id ^* and Iq ^* are set so that a direct current of Ia flows in the U phase and −Ia flows in the W phase, the motor rotor is positioned at θ = 30 degrees from the reference position of the U phase of the armature winding. Can be fixed. This position is a positioning position of the motor rotor when the d-axis inductance Ld is identified.

  In general, the two-phase voltage equation of a permanent magnet synchronous motor is given by the following Equation 1. In Equation 1, Ra is an armature winding resistance, Ld is a d-axis inductance, Lq is a q-axis inductance, ω is a rotational speed, ψa is a flux linkage number by a permanent magnet, and p is a differential operator.

In the present embodiment, when the motor constant is identified, DC current commands Id ^* and Iq ^* are applied and positioned at a predetermined position, in this case, θ = 30 degrees, and then the DC current command Id ^* Confirm that the detection current Id is 0 A with 0.

  Next, control is performed so that two of the three phases of the inverter control unit 110 are energized and the remaining one phase is opened. That is, by turning on the upper arm switching element 111 and the lower arm switching element 116, an arbitrary d-axis voltage command Vd_sig is applied so that a direct current of Ia flows in the U phase and −Ia flows in the W phase. At this time, the V-phase switching elements are all turned off and are opened as a high impedance state.

  Based on the d-axis voltage command Vd_sig, the output current vector output from the two-phase three-phase conversion means 108 is θ = 30 degrees, and the inductance identification means 109 performs a predetermined sampling of the detection current Id from the three-phase two-phase conversion means 103. Obtained at period Ts. The sampling period Ts is calculated and set by an arbitrary carrier frequency. Then, the d-axis inductance Ld is identified by a method described later using the d-axis voltage command Vd_sig, the detected current value Id, the rotation speed (ω = 0), and the rotor position (θ = 30 degrees).

  The positioning position of the motor rotor is not limited to θ = 30 degrees. The switching element of the inverter control unit 110 is opened so that the positioning position and the phase of the output current vector are parallel and one of the three phases of the permanent magnet synchronous motor 101 is opened and the other two phases are energized. Any position can be used as long as it can be realized by selecting and energizing one stone at a time from the lower arm. Alternatively, the switching element of the inverter control unit 110 may be selected and energized so as to energize at least two phases or three phases.

  A method for identifying the d-axis inductance Ld will be described in detail using voltage equations. The d-axis component of the voltage equation of Equation 1 is expressed by Equation 2 below.

  Next, when the voltage equation of Formula 2 is converted into a difference equation and the sampling period Ts is substituted and arranged, it is expressed by Formula 3.

  In the present embodiment, when the motor constant is identified, after the motor rotor is positioned at the position of θ = 30 degrees, the output current vector output from the two-phase / three-phase conversion means 108 is θ = 30 degrees. Since the motor rotor is stationary, ω = 0. The phase of the output current vector matches the direction of the magnetic flux by the motor rotor, that is, the d-axis phase. That is, by controlling the output current vector to be a current component parallel to the magnetic flux of the motor rotor, the d-axis inductance Ld can be obtained by the following formula 4 obtained by substituting ω = 0 into the formula 3.

  However, in Equation 4, when the sampling cycle Ts is short, the difference value of the denominator equation may become extremely small and the Ld calculated value may fluctuate greatly. As a countermeasure, it is conceivable to increase Ts or use a filter function. However, there is a possibility that the calculation error of Ld may increase. Therefore, as an alternative method, the following formula 5 derived from the formula 2 by transforming and approximating the integral form with ω = 0 is used. As a result, the variation factor in the Ld calculation can be minimized, and the d-axis inductance Ld can be identified with high accuracy.

  In Equation 5, k and n are discrete natural numbers (1 ≦ k ≦ n), Vd1 is a constant d-axis voltage, Ldn is a d-axis inductance at Idn, and Idn is a d-axis current Id at k = n.

Equation 5 will be described with reference to FIG. FIG. 4 is an explanatory diagram of the discretization calculation in motor inductance identification. As shown in FIG. 4, the d-axis pulse command voltage 401 and the d-axis instantaneous current 402 for each sampling period Ts when vd is applied are a discretized natural number k (1 ≦ k).
≦ n) is shown. Note that Tn = n · Ts.

Further, in the section of 1 ≦ k ≦ n, the d-axis pulse command voltage 401 is a constant single pulse.
d-axis pulse command voltage 401 = Vd1
It is.

  Under such conditions, the d-axis current Id draws a characteristic diagram represented by the d-axis instantaneous current 402. When Ld at the time point k = n is Ldn and Id is Idn, Ldn is expressed as Equation 5. , Can be derived from Equation 2 (where ω = 0). Therefore, the d-axis inductance Ld-d-axis current Id characteristic can be obtained by sequentially calculating Ldn corresponding to Idn while increasing n.

  Next, with the V-phase open, the upper arm switching element 113 and the lower arm switching element 114 are turned on so that a direct current of -Ia flows in the U phase and Ia flows in the W phase. A shaft voltage command Vd_sig is applied. Based on the d-axis voltage command Vd_sig, the output current vector output from the two-phase / three-phase conversion means 108 is θ = 210 degrees, and the inductance identification means 109 performs a predetermined sampling of the detected current Id from the three-phase / two-phase conversion means 103. Obtained at period Ts. Then, the d-axis inductance Ld is identified using the d-axis voltage command Vd_sig, the detected current value Id, the rotation speed (ω = 0), and the rotor position (θ = 30 degrees). The output current vector is rotated 180 degrees from θ = 30 degrees, and the direction of the current flowing through the U-phase and W-phase winding coils is opposite to that when θ = 30 degrees.

  An average value of the identified value of the d-axis inductance Ld at θ = 210 degrees and the value of the d-axis inductance Ld calculated when θ = 30 degrees is set is calculated. Further, as shown in Equation 5, the d-axis inductance Ld (motor inductance) at each rotor position is obtained by sequentially integrating the inverter output voltage, and the successive integration value is a three-phase two-phase conversion value of the phase current value Ia. Calculated by dividing by Id. As a result, the d-axis inductance Ld can be accurately identified from the small current region to the large current region. When the identification of the d-axis inductance Ld is completed, the application of the d-axis voltage command Vd_sig is terminated.

  As is apparent from the detailed description of the present embodiment, the motor control device of the present invention has the following effects. The motor control device of the present invention selects one stone or two stones among the switching elements of the upper arm while the motor rotor of the permanent magnet synchronous motor is stopped at a predetermined position, and the switching not selected by the upper arm. By selecting and energizing at least one switching element of the lower arm connected to the element, the d-axis inductance 1 is identified as the motor inductance 1 from the first output current vector flowing in the permanent magnet synchronous motor, and By selecting and energizing the switching element from the upper arm and the lower arm so as to be in the opposite direction to the first output current vector, the motor inductance 2 is obtained from the second output current vector flowing in the permanent magnet synchronous motor. Identifies axis inductance 2, and d-axis inductance 1 and d-axis inductor By calculating the average value of the transformer 2, it has inductance identifying means for identifying the motor inductance of the permanent magnet synchronous motor, and the inductance identifying means sequentially integrates the output voltage of the inverter control unit when identifying the motor inductance, The sequential integration value obtained thereby is divided by the three-phase two-phase conversion value of the phase current value output from the current detection unit. As a result, the motor inductance can be accurately identified from the small current region to the large current region, and it is possible to prevent the operation responsiveness of the permanent magnet synchronous motor from deteriorating or causing malfunctions such as step-out.

(Embodiment 2)
Hereinafter, another embodiment of the motor control device of the present invention will be described. The configuration of the motor control apparatus according to the second embodiment of the present invention is the same as that of the first embodiment shown in FIG. 1, but the positioning position of the motor rotor at the time of motor inductance identification is different from that of the first embodiment.

  In the first embodiment, the phase of the d-axis of the positioned motor rotor and the phase of the output current vector output from the two-phase three-phase conversion means 108 based on Vd_sig applied when measuring the motor inductance are obtained. It was controlled to be in the same direction.

  In the present embodiment, the phase of the d-axis of the motor rotor to be positioned and the phase of the output current vector output from the two-phase / three-phase conversion means 108 based on Vq_sig applied when measuring the motor inductance is 90. The direction is controlled so as to be deviated. FIG. 5 is a diagram showing the relationship between the U, V, W coordinates of the permanent magnet synchronous motor 101, the position of the motor rotor (permanent magnet), and the dq coordinates when the q-axis inductance Lq is identified in the second embodiment of the present invention. is there.

  The operation of the inductance identification unit 109 will be described. The inductance identification process can be performed when a start command for the permanent magnet synchronous motor 101 is given. The permanent magnet synchronous motor 101 can be driven using the motor constant obtained in the identification process. The motor constant identified by this identification process is the q-axis inductance Lq.

  In the present embodiment, in order to identify the motor constant while the motor rotor of the permanent magnet synchronous motor 101 is stationary, the magnetomotive force due to the U-phase current of the armature winding is used as a reference, and the reference position of θ = 0 is used. deal with.

By turning on the switching element 112 of the upper arm and the switching elements 114 and 116 of the lower arm, a current command Id so that a direct current of Ia in the V phase, -Ia / 2 in the U phase and -Ia / 2 in the W phase flows. ^{When *} and Iq ^* are set, the motor rotor can be fixed at a position of θ = 120 degrees. This position is set as the positioning position of the motor rotor when the q-axis inductance Lq is identified. This positioning position is a position rotated 90 degrees from the positioning position of the motor rotor when the d-axis inductance Ld is identified. The position rotated 90 degrees in the opposite direction to the above may be used as the positioning position.

In the present embodiment, when the motor constant is identified, the DC current commands Id ^* and Iq ^* are applied and positioned at a predetermined position, in this case, the position of θ = 120 degrees, and then the DC current command Id ^* Confirm that the detection current Id is 0 A with 0. The position of θ = 120 degrees is rotated 90 degrees from the motor rotor positioning position in the first embodiment, and the current component orthogonal to the magnetic flux of the rotated motor rotor and the output current vector are parallel. .

  Next, control is performed so that two of the three phases of the inverter control unit 110 are energized and the remaining one phase is opened. In other words, by turning on the switching element 111 of the upper arm and the switching element 116 of the lower arm, the V phase is released, and a direct current of Ia flows in the U phase and −Ia flows in the W phase. Vq_sig is applied.

Based on the q-axis voltage command Vq_sig, the output current vector output from the two-phase / three-phase conversion unit 108 is set to θ = 30 degrees, and the inductance identification unit 109 detects the detected current Iq from the three-phase / two-phase conversion unit 103. Are acquired at a predetermined sampling period Ts. Here, since the position of θ = 120 degrees, which is the positioning position of the motor rotor, is orthogonal to the applied output current vector, the q-axis inductance Lq can be calculated. The sampling period Ts is calculated and set by an arbitrary carrier frequency. Then, the q-axis inductance Lq is identified by a method described later using the q-axis voltage command Vq_sig, the detected current value Iq, the rotation speed (ω = 0), and the rotor position (θ = 120 degrees).

  The positioning position of the motor rotor is not limited to θ = 120 degrees. The switching element of the inverter control unit 110 is the upper arm so that the positioning position and the phase of the output current vector are orthogonal, and one of the three phases of the permanent magnet synchronous motor 101 is opened and the other two phases are energized. Any position can be used as long as it can be realized by selecting and energizing one stone at a time from the lower arm. Alternatively, the switching element of the inverter control unit 110 may be selected and energized so as to energize at least two phases or three phases.

  A method for identifying the q-axis inductance Lq will be described in detail using voltage equations. The q-axis component of the voltage equation of Equation 1 is expressed by Equation 6 below.

  Next, the voltage equation of Equation 6 is converted into a difference equation, and the sampling period is arranged by substituting Ts. In this embodiment, when the motor constant is identified, after positioning the motor rotor at the position of θ = 120 degrees, the output current vector output from the two-phase / three-phase conversion means 108 is θ = 30. If the rotation of the motor rotor is performed within a short time that can be ignored, ω = 0 because it is in a stationary state. Further, the direction of the magnetic flux by the motor rotor and the phase of the output current vector, that is, the q-axis phase are orthogonal to each other. That is, by controlling the output current vector so as to be a current component orthogonal to the magnetic flux of the motor rotor, it can be transformed as shown in Equation 7 below, and the q-axis inductance Lq can be obtained.

  Here, Formula 7 also has the same denominator characteristic as Formula 4. Similarly to the derivation process of Equation 5, the q-axis inductance Lq can be identified with high accuracy by using the following Equation 8 derived from Equation 6 by transforming and approximating the integral form with ω = 0.

  Here, k and n are discretized natural numbers (1 ≦ k ≦ n), Vq1 is a q-axis constant voltage, Lqn is a q-axis inductance Lq when Iqn, and Iqn is a q-axis current Iq when k = n.

Further, in the section of 1 ≦ k ≦ n, the q-axis pulse voltage is a constant single pulse, so that q-axis pulse voltage = Vq1.
It is.

  Therefore, the q-axis inductance Lq-q-axis current Iq characteristic can be obtained by sequentially calculating Lqn corresponding to Iqn while increasing n.

  Next, the q-axis inductance Lq when the output current vector is rotated 180 degrees is calculated. With the V-phase open, by turning on the switching element 113 of the upper arm and the switching element 114 of the lower arm, an arbitrary q-axis voltage command can be set so that a direct current of -Ia flows in the U phase and Ia flows in the W phase. Vq_sig is applied. Based on the q-axis voltage command Vq_sig, the output current vector output from the two-phase three-phase conversion means 108 is θ = 210 degrees, and the inductance identification means 109 performs a predetermined sampling of the detected current Iq from the three-phase two-phase conversion means 103. Obtained at period Ts. Then, the q-axis inductance Lq is identified using the q-axis voltage command Vq_sig, the detected current value Iq, the rotation speed (ω = 0), and the rotor position (θ = 120 degrees). The output current vector is rotated 180 degrees from θ = 30 degrees, and the direction of the current flowing through the U-phase and W-phase winding coils is opposite to that when θ = 30 degrees.

  The average value of the q-axis inductance Lq value at θ = 210 degrees identified above and the q-axis inductance Lq value calculated when θ = 30 degrees is set is calculated. Further, the q-axis inductance Lq (motor inductance) at each rotor position is obtained by sequentially integrating the inverter output voltage as shown in Equation 8, and the successive integration value is converted into a three-phase two-phase conversion value of the phase current value Ia. Calculated by dividing by Iq. As a result, the q-axis inductance Lq can be accurately identified from the small current region to the large current region. When the identification of the q-axis inductance Lq is completed, the application of the q-axis voltage command Vq_sig is terminated.

  As is apparent from the detailed description of the present embodiment, the motor control device of the present invention has the following effects. The motor control device of the present invention selects one stone or two stones among the switching elements of the upper arm while the motor rotor of the permanent magnet synchronous motor is stopped at a predetermined position, and the switching not selected by the upper arm. By selecting and energizing at least one of the switching elements of the lower arm connected to the element, the q-axis inductance 1 is identified as the motor inductance 1 from the first output current vector flowing in the permanent magnet synchronous motor, and When the switching element is selected from the upper arm and the lower arm so as to be in the opposite direction to the first output current vector and energized, the second output current vector flowing in the permanent magnet synchronous motor is converted into a motor inductance 2 q Identify the axis inductance 2, q-axis inductance 1 and q-axis inductor By calculating the average value of the transformer 2, it has inductance identifying means for identifying the motor inductance of the permanent magnet synchronous motor, and the inductance identifying means sequentially integrates the output voltage of the inverter control unit when identifying the motor inductance, The successive integration value obtained thereby is divided by the three-phase two-phase conversion value of the phase current value. As a result, the motor inductance can be accurately identified from the small current region to the large current region, and it is possible to prevent the operation responsiveness of the permanent magnet synchronous motor from deteriorating or causing malfunctions such as step-out.

  In addition, the motor control apparatus of the form with which the said Embodiment 1 and Embodiment 2 are used together may be sufficient.

The motor control device of the present invention can realize the identification of the motor constant with high accuracy and can prevent the occurrence of operation troubles such as a decrease in operation responsiveness and step-out of the permanent magnet synchronous motor. It is useful as a motor control device used for an electric device having a driven permanent magnet synchronous motor.

101 Permanent magnet synchronous motor 102a, 102b, 102c Current sensor (current detection unit)
DESCRIPTION OF SYMBOLS 103 Three-phase two-phase conversion means 104 Motor rotor position and speed estimation means 106 Speed control means 107 Current control means 108 Two-phase three-phase conversion means 109 Inductance identification means 110 Inverter control part 111, 112, 113, 114, 115, 116 Switching element 121, 122, 123, 124, 125, 126 Free-wheeling diode 131 Driver 401 d-axis pulse command voltage 402 d-axis instantaneous current

Claims (3)

A current detection unit for detecting an armature current of a permanent magnet synchronous motor having a permanent magnet in the rotor, and a phase current value output from the current detection unit is used to set a rotation speed and an output torque of the permanent magnet synchronous motor. A motor control device comprising: a vector control unit that controls the value; and an inverter control unit that has three stones in the upper arm and three stones in the lower arm and drives the three-phase permanent magnet synchronous motor.
The vector control unit selects one stone or two stones among the switching elements of the upper arm in a state where the motor rotor of the permanent magnet synchronous motor is stopped at a predetermined position by current control of the armature current, and By selecting and energizing at least one of the switching elements of the lower arm connected to the switching element not selected by the upper arm, the permanent magnet synchronization is obtained from the first output current vector flowing in the permanent magnet synchronous motor. The permanent magnet synchronous motor is identified by identifying the motor inductance 1 of the motor and energizing the switching element by selecting a switching element from the upper arm and the lower arm so as to be in a direction opposite to the first output current vector. Motor inductance of the permanent magnet synchronous motor from the second output current vector flowing in the motor Identified 2, by calculating the average value of the motor inductance 1 and the motor inductance 2, it has an inductance identifying means for identifying the motor inductance of the permanent magnet synchronous motor,
The inductance identification means sequentially integrates the output voltage of the inverter control unit when identifying the motor inductance, and converts the successive integration value obtained thereby into three-phase to two-phase conversion of the phase current value output from the current detection unit. Configured to divide by value,
Motor control device. The inductance identifying means controls the first output current vector of the inverter control unit to be a current component parallel to the magnetic flux of the motor rotor, and the second output current vector of the inverter control unit is the first output current vector. Configured to identify the d-axis inductance of the permanent magnet synchronous motor by controlling to be opposite to the output current vector of 1.
The motor control device according to claim 1. The inductance identifying means rotates the electrical angle by 90 degrees in any motor rotation direction from a predetermined position where the motor rotor is stopped, and the first output current vector of the inverter control unit is a current orthogonal to the magnetic flux of the motor rotor. And the second output current vector of the inverter control unit is controlled to be in the opposite direction to the first output current vector, whereby the q-axis inductance of the permanent magnet synchronous motor is controlled. The motor control device according to claim 1, wherein the motor control device is identified.