JP2015142464A - motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device which improves a start success rate in start-up operation of a synchronous motor and is capable of reducing vibrations during the start-up operation.SOLUTION: In the motor control device, a voltage setting unit 50 sets a voltage for positioning electrification of a rotor before starting activation of a synchronous motor M. A positioning control unit 62 uses the voltage for positioning electrification to perform positioning electrification of the synchronous motor M. In a two-phase/three-phase conversion unit 22, a voltage vector on a rotation coordinate system is converted into a voltage vector on a stationary coordinate system. In a three-phase/two-phase conversion unit 21, a current vector on the stationary coordinate system in the case of driving the synchronous motor M is converted into a current vector on the rotation coordinate system and a δ-axis current is calculated by a driving unit 10. When the δ-axis current is a predetermined current value and flows continuously for a predetermined time, a positioning determination processing unit 61 determines that the rotor is positioned, and a positioning control unit 62 determines that the rotor is positioned.

Description

  The present invention relates to a motor control device that drives a synchronous motor.

  In the motor control device described in Patent Literature 1, when starting a synchronous motor that performs position sensorless driving, if the motor is started without knowing the position of the stopped rotor (rotor), the motor does not start well. There is a fear. Therefore, in Patent Document 1, the motor is started after performing energization for positioning the rotor at a predetermined position. That is, in Patent Document 1, by performing positioning energization, the process proceeds to the next startup sequence on the assumption that the rotor is positioned at a predetermined position.

JP2013-207868A

  However, in the technique described in Patent Document 1, if the rotor is not positioned at a predetermined position even if the rotor is energized, the control axis γ-δ axis and the real axis d Since the motor start sequence is started in a state where there is a large deviation from the −q axis, it is assumed that the start control is not performed correctly and the motor cannot be started. In particular, when the position of the rotor is a predetermined position at an electrical angle of 0 degrees and the predetermined position is at an electrical angle of 180 degrees, the rotor does not rotate even if positioning energization is performed. In other words, if there is a rotor at the electrical angle of 180 degrees, the rotor cannot be positioned at a predetermined position even if positioning energization is performed. When the startup operation is performed assuming that the startup control is not performed correctly, there is a problem that the startup success rate decreases.

  In addition, if the motor is started without the rotor being positioned at a predetermined position, the rotor does not rotate smoothly, causing vibration during start-up operation, and causing damage to the motor or the device body equipped with the motor due to vibration. There is.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a motor control device that has a high startup success rate during the startup operation of a synchronous motor and can reduce vibration during the startup operation.

  In order to solve the above-described problems and achieve the object, a motor control device according to a first aspect of the present invention is a motor control device that controls a synchronous motor having a rotor and a stator, and starts up the synchronous motor. Before starting, a voltage command generation unit that sets a positioning energization voltage for performing positioning energization for positioning the rotor and generates a voltage command, and a three-phase based on the voltage command output from the voltage command generation unit A PWM generator that generates a PWM signal; an inverter that converts DC power supplied from a DC power source into three-phase AC power using the PWM signal; and supplies the synchronous motor; and a phase current that flows through the stator winding And a three-phase phase current (Iu, Iv, Iw) based on the phase current of the synchronous motor detected by the detection unit, and a rotary seat A three-phase to two-phase converter that converts the two-phase current (Iγ, Iδ) of the system, and a δ-axis current Iδ from the two-phase current output from the three-phase to two-phase converter, and the δ-axis And a positioning determination processing unit that determines that the rotor has been positioned when the current Iδ is equal to or greater than a predetermined current value and continuously flows for a predetermined time.

  In the motor control device according to the present invention, in the above invention, when the positioning determination processing unit determines that the rotor is not positioned, a predetermined angle is set to the positioning energization angle θ that is a phase of the positioning energization voltage. A positioning energization angle setting unit that sets a new energization angle θ by adding φ and outputs it to the voltage command generation unit is further provided, and the positioning energization angle setting unit includes a positioning energization angle θ newly set during positioning energization The above-mentioned positioning energization is performed using

  In the motor control device according to the present invention, in the above invention, when the positioning determination processing unit continues to determine that the rotor is not positioned, the positioning energization angle θ set by the positioning energization angle setting unit The positioning energization is repeated until the angle becomes a predetermined angle.

  The motor control device according to the present invention has the effect of improving the startup success rate of the synchronous motor having no position detection sensor and reducing the vibration during startup.

FIG. 1 is a diagram illustrating a configuration of a motor control device according to an embodiment. FIG. 2 is a diagram illustrating a relationship among the UVW fixed coordinate system, the γ-δ coordinate system, and the dq coordinate system in the embodiment. FIG. 3 is a diagram for explaining the positioning energization process before the start of the start in the embodiment. FIG. 4 is a diagram illustrating a processing flow during start-up operation in the embodiment.

  Embodiments of a motor control device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment)
A motor control device 1 according to an embodiment will be described with reference to FIG. FIG. 1 mainly shows the configuration relating to the positioning energization processing of the motor control device according to the present invention. The motor control device 1 generates a control signal by PWM modulation and controls the motor M which is a synchronous motor. The motor M is, for example, a PMSM (permanent magnet synchronous motor), and includes a rotor that has a permanent magnet and rotates, and a stator that has a stator coil and generates a rotating magnetic field for rotating the rotor. In driving the synchronous motor, since it is necessary to synchronize the rotation of the rotor and the rotating magnetic field generated by the stator coil, it is necessary to detect the position (rotational position) of the rotor. As described above, when the motor M is a synchronous motor having no position detection sensor, position sensorless control is required.

  The motor control device 1 performs a steady operation in which vector control is performed so that a synchronous motor (hereinafter referred to as a synchronous motor) M having no position detection sensor is rotated at a command rotational speed. When starting the synchronous motor M, the motor control device 1 does not start this steady operation, but first performs the startup operation of the synchronous motor M in the startup operation mode provided for startup, and then starts the steady operation from the startup operation mode. The mode is shifted to the mode, and the synchronous motor M is normally operated in the steady operation mode.

  Conventionally, when starting the synchronous motor M that performs position sensorless control in the start-up operation mode described above, the start-up operation mode is entered on the assumption that the rotor is positioned at a predetermined position after energizing the rotor. It was.

However, if the rotor does not rotate and is not positioned at a predetermined position even after positioning energization, there is a possibility that the motor will not start or vibration may occur even if it is started.
Therefore, in the present embodiment, as a problem at the time of starting the synchronous motor that performs position sensorless control, the rotor rotates after positioning current supply rather than entering the startup operation mode after positioning current supply and assuming that positioning has been performed. After confirming the positioning at a predetermined position, the start operation mode is entered.

  That is, in the present embodiment, the positioning determination is performed after the energization of positioning, and the start operation mode is entered only when it is determined that the rotor is rotated and positioned. In this positioning determination, it is determined that “the rotor has been rotated and stopped at a predetermined position” after being energized as “positioned”. Specifically, when positioning energization is performed and the rotor does not rotate, all the flowing current flows as the γ-axis (d-axis) current, and the δ-axis (q-axis) current does not flow. A voltage is generated in the q-axis direction. As a result, not only the γ-axis current but also the δ-axis (q-axis) current flows. When the rotor stops, the δ-axis current stops flowing. That is, it is determined as “positioned”. In this way, if it is known that the rotor has stopped after rotating by positioning energization, it can be determined that the rotor is positioned at a predetermined position. Therefore, if the synchronous motor M is started at that time, the synchronous motor M As a result, the startup success rate can be improved, and vibration during startup can be reduced.

  In this embodiment, in order to reduce the amount of calculation for positioning determination, the actual magnetic flux position is estimated without using the dq rotation coordinate system that requires the actual magnetic flux position (d-axis position) to be estimated. A γ-δ rotating coordinate system that is a control axis that does not perform the above is used. FIG. 2 shows a UVW fixed coordinate system corresponding to the direction of the magnetic field generated by the three-phase windings of the U-phase, V-phase, and W-phase of the stator (stator) of the synchronous motor M. The relationship between the q rotating coordinate system and the γ-δ rotating coordinate system rotating in synchronization with the rotating magnetic field generated by the stator is shown.

  The d-axis is the direction of the magnetic pole N of the rotor in the synchronous motor M, and the axis shifted from the d-axis in the rotational direction by 90 electrical degrees is the q-axis. A coordinate axis corresponding to the dq axis with respect to the rotating magnetic field generated by the stator is a γ-δ axis, and a rotation angle from the α axis (U-phase axis) to the γ axis is θe. Here, the α axis is an axis of an α-β fixed coordinate system obtained by converting the UVW fixed coordinate system into a two-phase fixed coordinate system by three-phase to two-phase conversion, and the α axis is set in the same direction as the U axis. The rotor is rotating counterclockwise at an angular velocity ωe, with a shift between the γ-axis and the d-axis, that is, a phase difference Δθ.

  In the start-up operation, when the motor control device 1 does not estimate the rotor position, the motor start-up success rate is high during the start-up operation of the motor. It is necessary to position the initial position at a predetermined position. In the motor control device 1 of the present invention, as shown in FIG. 3, positioning control by specific phase energization is performed.

  In the motor control device 1 of the present embodiment, for example, as shown in FIG. 3, positioning energization is performed so that the U-axis position is a predetermined position and the d-axis and the U-axis coincide.

  Next, the configuration of the motor control device 1 according to the embodiment of the positioning energization according to the present invention will be specifically described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of the motor control device 1. In FIG. 1, the γ-axis voltage command value is Vγ *, and the δ-axis voltage command value is Vδ * (* represents the command value).

  The motor control device 1 includes an inverter 10, a generation unit 20, and a detection unit 80, and performs sensorless control of a synchronous motor.

  The inverter 10 receives DC power from a DC power source (not shown) and receives three-phase (U-phase, V-phase, W-phase) PWM signals Up, Un, Vp, Vn, Wp, Wn from the generator 20. The inverter 10 has, for example, six switching elements (not shown), and performs switching operation of each switching element at a predetermined timing in accordance with the three-phase PWM signals Up to Wn, so that the three-phase AC signals U, V, W Is generated and supplied to the synchronous motor M to drive the synchronous motor M.

  The detection unit 80 detects a current of two phases among the three phases of the U phase, the V phase, and the W phase. Specifically, the detection unit 80 includes a current sensor 81 and a current sensor 82. The current sensor 81 detects a U-phase current iu, and the current sensor 82 detects a W-phase current iw and outputs it to the generation unit 20.

  The generation unit 20 receives the speed command ωm * from the outside (for example, a host controller), and receives the two-phase currents iu and iw from the detection unit 80. The generation unit 20 calculates the remaining one-phase current iv from the two-phase currents iu and iw, and based on the speed command ωm * and the three-phase currents iu, iv and iw, the three-phase PWM signals Up to Wn is generated. For example, the generation unit 20 generates the three-phase PWM signals Up to Wn so that the rotor in the motor M rotates according to the speed command ωm *.

  Specifically, the generation unit 20 includes a three-phase to two-phase conversion unit 21, a PWM generation unit 23, a current command generation unit 30, and a voltage command generation unit 40.

  The three-phase to two-phase conversion unit 21 calculates the remaining one-phase current iv from the two-phase currents iu and iw detected by the detection unit 80 when driving the synchronous motor M as a relational expression “iv = −iu−iw”. The current vector (iu, iv, iw) in the fixed coordinate system (UVW coordinate system) is converted into the current vector (iγ, iδ) in the rotating coordinate system (γ-δ coordinate system) or the dq coordinate system. To the current vector (id, iq). Note that the rotating coordinate system uses the γ-δ coordinate system when positioning energization is performed, and uses the dq coordinate system assuming that the γ-δ coordinate system and the dq coordinate system coincide with each other from the start-up operation.

  The current command generation unit 30 generates a d-axis current command id * and a q-axis current command iq * from the speed command ωm * and the two-phase current (id, iq) received from the three-phase to two-phase conversion unit 21, and the voltage command Output to the command generator 40.

  Specifically, the current command generator 30 includes a position / velocity estimator 31, a subtracter 32, a d-axis current setter 33, a q-axis current setter 34, a subtractor 35, and a subtractor 36.

  The position / velocity estimator 31 receives the d-axis current id and the q-axis current iq from the three-phase / two-phase converter 21 and receives a d-axis voltage command Vd * and a q-axis voltage command Vq *, which will be described later, from the voltage setter 50. receive. The position / speed estimator 31 calculates the electrical estimated angular velocity ωe and the phase angle θdq of the rotating coordinate system based on the d-axis current id, the q-axis current iq, the d-axis voltage command Vd *, and the q-axis voltage command Vq *. Estimate each. The position / velocity estimator 31 outputs the electrical estimated angular velocity ωe to the 1 / Pn converter 37 and outputs the phase angle θdq to the three-phase to two-phase converter 21 and the two-phase to three-phase converter 22.

  The 1 / Pn converter 37 receives the electrical estimated angular velocity ωe from the position / velocity estimator 31. The 1 / Pn converter 37 multiplies the electrical estimated angular velocity ωe by, for example, 1 / Pn (Pn is the number of pole pairs) to convert the electrical estimated angular velocity ωe into the mechanical estimated angular velocity ωm of the rotor in the motor M. Convert. The 1 / Pn converter 37 outputs the mechanical estimated angular velocity ωm to the subtractor 32.

  The subtractor 32 receives the mechanical estimated angular velocity ωm from the 1 / Pn converter 37 and receives the velocity command ωm * from the outside (for example, a host controller). The subtractor 52 subtracts the estimated angular speed ωm from the speed command ωm * to obtain a speed deviation Δω, and outputs the obtained speed deviation Δω to the q-axis current setting unit 34.

  The q-axis current setting unit 34 receives the speed deviation Δω from the subtractor 32. The q-axis current setting unit 34 sets the q-axis current command iq * so that the speed deviation Δω approaches zero. The q-axis current setting unit 34 outputs the set q-axis current command iq * to the subtracter 36.

  The subtractor 36 receives the q-axis current command iq * from the q-axis current setter 34 and receives the q-axis current iq from the three-phase to two-phase conversion unit 21. The subtractor 36 subtracts the q-axis current iq from the q-axis current command iq * to obtain the q-axis current deviation Δiq, and outputs the obtained q-axis current deviation Δiq to the voltage command generation unit 40.

  The d-axis current setting unit 33 generates a d-axis current command id * with a predetermined value (for example, a fixed value) and outputs it to the subtracter 35.

  The subtractor 35 receives the d-axis current command id * from the d-axis current setting unit 33 and receives the d-axis current id from the three-phase to two-phase conversion unit 21. The subtractor 35 subtracts the d-axis current id from the d-axis current command id * to obtain a d-axis current deviation Δid, and outputs the obtained d-axis current deviation Δid to the voltage command generation unit 40.

  The voltage command generator 40 obtains a d-axis voltage command Vd * and a q-axis voltage command Vq * according to the d-axis current deviation Δid and the q-axis current deviation Δiq from the current command generator 30. The voltage command generation unit 40 converts the obtained d-axis voltage command Vd * and q-axis voltage command Vq into a three-phase voltage command (Vu *, Vv *, Vw *) and outputs it to the PWM generation unit 23.

  Specifically, the voltage command generation unit 40 includes a voltage setting unit 50 and a two-phase to three-phase conversion unit 22.

  The voltage setting unit 50 includes a δ (q) axis voltage setting unit 51 and a γ (d) axis voltage setting unit 52. The γ (d) axis voltage setting unit 52 sets the d axis voltage command Vd * according to the d axis current deviation Δid received from the subtractor 35 (for example, so that the d axis current deviation Δid approaches zero). The δ (q) axis voltage setting unit 51 sets the q axis voltage command Vq * according to the q axis current deviation Δiq received from the subtractor 36 (for example, so that the q axis current deviation Δiq approaches zero). The voltage setting unit 50 outputs the set d-axis voltage command Vd * and q-axis voltage command Vq * to the position / speed estimator 31 and the two-phase / three-phase conversion unit 22.

  The two-phase / three-phase conversion unit 22 converts the two-phase d-axis voltage command Vd * and the q-axis voltage command Vq * received from the voltage setting unit into three-phase voltage commands (Vu *, Vv *, Vw *). And output to the PWM generator 23.

  Based on the three-phase voltage command (Vu *, Vv *, Vw *) received from the two-phase / three-phase converter 22, the PWM generator 23 is a three-phase (U phase, V phase, W phase) PWM. Signals Up, Un, Vp, Vn, Wp, Wn are generated and output to inverter 10.

  The above is the description of the configuration of the motor control device that performs sensorless control of the synchronous motor. From here, the positioning control of the present invention will be described. As a configuration of the positioning means 60 related to the positioning control, in addition to the three-phase to two-phase conversion unit 21 and the voltage command generation unit 40 in the generation unit 20, a positioning determination processing unit 61, a positioning control unit 62, and positioning energization The angle setting unit 63 is provided, and the current command generation unit 30 is not used.

  Further, the voltage setting unit 50 for setting the voltage command (Vγ *, Vδ *) for positioning energization provided in the voltage command generation unit 40, and the voltage command for the rotary coordinate system γ-δ set by the voltage setting unit 50 ( A two-phase / three-phase converter 22 that converts Vγ *, Vδ *) into three fixed coordinate system UVW voltage commands (Vu *, Vv *, Vw *) is used as the positioning means 60.

  The voltage setting unit 50 sets a two-phase voltage command (Vγ *, Vδ *) used for positioning energization of the rotor of the synchronous motor before starting the start-up operation of the synchronous motor M. The voltage setting unit 50 includes a δ (q) axis voltage setting unit 51 and a γ (d) axis voltage setting unit 52. When energizing the positioning, the voltage command is set as the γδ axis voltage command.

  The γ (d) -axis voltage setting unit 52 γ of a voltage vector (hereinafter referred to as a positioning energization voltage vector) on a rotating coordinate system (γ-δ coordinate system) necessary for rotating the rotor by energizing positioning. A γ-axis voltage command Vγ * for generating the component Vγ is output to the two-phase to three-phase converter 22. The γ-axis voltage Vγ is a fixed voltage, and the γ-axis voltage command Vγ * is preset as a voltage command for generating a γ-axis voltage that obtains a sufficiently large torque to drive the stationary load of the synchronous motor M. .

  The δ (q) -axis voltage setting unit 51 sets a δ-axis voltage command Vδ * that sets the δ component Vδ of the positioning energization voltage vector to a predetermined value (0 V) on the rotating coordinate system (γ-δ coordinate system). Output to the phase-3 phase converter 22.

  Thus, before starting the synchronous motor M, the γ-axis voltage setting unit 52 and the δ-axis voltage setting unit 51 of the voltage setting unit 50, for example, Vδ * = 0, Vγ * = (predetermined value). The positioning energization voltage is set.

  The two-phase / three-phase conversion unit (γ-δ / UVW) 22 includes an angle θ set by a positioning energization angle setting unit 63 described later and a rotational coordinate system (γ-δ coordinate system set by a voltage setting unit 50). The positioning energization voltage vector in the fixed coordinate system (UVW coordinate system) is generated using the above positioning energization voltage vector.

Specifically, the two-phase / three-phase conversion unit 22 determines the positioning voltage vector (Vγ, Vδ) in the rotating coordinate system (γ-δ coordinate system), that is, the γ-axis voltage command value Vγ * and the δ-axis voltage command Vδ *. Is received from the voltage setting unit 50. The two-phase / three-phase conversion unit 22 receives a positioning energization angle θ described later from the positioning energization angle setting unit 63. The two-phase / three-phase conversion unit 22 converts the two-phase positioning energization voltage vector (Vγ, Vδ) in the rotating coordinate system (γ-δ coordinate system) into a fixed coordinate system (UVW coordinate) by using the following formulas 1 to 3, for example. System) to three-phase positioning energized voltage vectors (Vu, Vv, Vw).
Vu = (√ (2/3)) × {Vγ × cos θ−Vδ × sin θ} Equation 1
Vv = (√ (1/2) × Vγ + √ (1/6) × Vδ) × sin θ
+ (√ (1/2) × Vδ−√ (1/6) × Vγ) × cos θ (2)
Vw = (√ (1/6) × Vδ−√ (1/2) × Vγ) × sin θ
− (√ (1/6) × Vγ + √ (1/2) × Vδ) × cos θ (3)

  The two-phase / three-phase conversion unit 22 outputs the positioning energization voltage vector (Vu, Vv, Vw) converted from the rotation coordinate system (γ-δ coordinate system) to the fixed coordinate system (UVW coordinate system) to the PWM generation unit 23. To do.

  The PWM generation unit 23 generates three-phase U, V, W (θ is a fixed value) voltage corresponding to the positioning energization voltage vector converted by the two-phase / three-phase conversion unit 22 via the inverter 10 and a synchronous motor. By supplying to M, positioning energization is performed to the synchronous motor M.

  Specifically, the PWM generation unit 23 performs positioning energization voltage vectors (Vu, Vv, Vw) in a fixed coordinate system (UVW coordinate system), that is, a U-phase voltage command Vu *, a V-phase voltage command Vv *, and a W-phase voltage. Command Vw * is received from the two-phase / three-phase converter 22. The PWM generator 23 generates a PWM signal based on the U-phase voltage command Vu *, the V-phase voltage command Vv *, and the W-phase voltage command Vw * and supplies the PWM signal to the inverter 10. As a result, the PWM generator 23 energizes the synchronous motor M via the inverter 10.

  The three-phase to two-phase conversion unit 21 calculates the remaining one-phase current iv from the two-phase currents iu and iw detected by the detection unit 80 when driving the synchronous motor M as a relational expression “iv = −iu−iw”. The current vector (iu, iv, iw) in the fixed coordinate system (UVW coordinate system) is converted into the current vector (iγ, iδ) in the rotating coordinate system (γ-δ coordinate system).

The three-phase to two-phase converter 21 receives the detected value of the U-phase current iu from the current sensor 81 and receives the detected value of the W-phase current iw from the current sensor 82. Further, the three-phase to two-phase conversion unit 21 receives the positioning energization angle θ from the positioning energization angle setting unit 63 described later. For example, the three-phase to two-phase conversion unit 21 converts the current vector (iu, iv, iw) in the fixed coordinate system (UVW coordinate system) to the rotational coordinate system (γ-δ coordinate system) by the following formulas 4 and 5. To current vector (iγ, iδ).
iγ = (√2) {iu × cos (θ + π / 6) −iw × sin θ} Equation 4
iδ = − (√2) {iu × sin (θ + π / 6) + iw × cos θ} Equation 5

  The three-phase to two-phase conversion unit 21 calculates the δ component of the current vector in the converted rotational coordinate system (γ-δ coordinate system), that is, the δ-axis current Iδ, and outputs the calculated δ component to the positioning determination processing unit 61 described later.

  The positioning determination processing unit 61 is an absolute value of the δ-axis current Iδ output from the three-phase to two-phase conversion unit 21 when the positioning control unit 62 (described later) performs positioning energization before the start-up operation starts (Iδ is DC). Is determined to be greater than or equal to a predetermined current value and continuously flowed for a predetermined time to determine whether or not the rotor has been positioned. When the rotor does not rotate, all the flowing current flows as the γ-axis (d-axis) current Iγ, and the δ-axis (q-axis) current Iδ does not flow. When the rotor rotates, only the γ-axis current Iγ Although the δ-axis current Iδ also flows (the δ-axis current Iδ is not only positive but can be negative), the fact that the δ-axis current Iδ stops flowing when the rotor stops is used. Specifically, the positioning determination processing unit 61 detects the current value of the δ-axis current Iδ output from the three-phase to two-phase conversion unit 21, and the absolute value of the detected current value is equal to or greater than a predetermined current value. And if it stops flowing after flowing continuously for a predetermined time, it is determined that “the rotor has rotated and stopped”, that is, the rotor has been “positioned” at a predetermined position. The predetermined current value and the predetermined time are set based on the experimental results depending on the rating of the motor actually used and the load of the motor.

  The positioning control unit 62 performs positioning energization. When the positioning determination processing unit 61 determines that the rotor is positioned, the positioning control unit 62 starts the starting operation at that time. That is, if the rotor is positioned at a predetermined position, the rotor can be started at a high startup success rate, and a smooth startup operation with less vibration is possible.

  Further, when the positioning determination processing unit 61 determines that the rotor is not positioned (after the start of positioning energization, the positioning control unit 62 did not continuously flow the δ-axis current Iδ at a predetermined current value for a predetermined time. In this case, the rotor is not rotating or may not be positioned at a predetermined position even if it is rotated. Therefore, positioning energization is performed again by changing the phase (energization angle θ) of the positioning energization voltage vector. If it is determined that positioning has been performed again by positioning energization, the positioning control unit 62 starts the startup operation at that time, but if it is determined that positioning has not been performed, the positioning control unit 62 further changes the phase of the positioning energization voltage vector. The positioning energization is retried (repeated) a predetermined number of times. The number of retries for positioning energization can be set to an arbitrary number according to design specifications.

  The positioning energization angle setting unit 63 sets the positioning energization angle θ for determining the phase of the positioning energization voltage when performing the positioning energization processing. The positioning energization angle θ corresponds to the rotation angle θe from the α axis (U axis) to the γ axis shown in FIG. If the positioning determination processing unit 61 does not determine that the rotor has been positioned, the positioning control unit 62 instructs the positioning energization angle setting unit 63 to change the positioning energization angle θ and retries the positioning energization. When receiving an instruction to change the positioning energization angle θ from the positioning control unit 62, the positioning energization angle setting unit 63 sets a new positioning energization angle θ by adding a predetermined angle φ to the positioning energization angle θ before the change instruction. It outputs to the phase-3 phase conversion part 22 and the 3 phase-2 phase conversion part 21, respectively. Since the predetermined angle φ needs to be positioned after the rotor has been rotated, the phase is separated from the previous positioning energization angle θ by a predetermined amount (for example, φ = 90 °, φ = 120 °, etc.). It is desirable to set to. Further, the number of retries for positioning energization is related to this φ, and the electrical angle of one rotation of the rotor is, for example, 360 ° for a 2-pole synchronous motor and 720 ° for a 4-pole synchronous motor. You may make it repeat retry until it exceeds the electrical angle of rotation.

  FIG. 4 is a flow chart of the synchronous motor start-up process including the positioning energization process according to the present invention. When the activation process is started, the positioning control unit 62 instructs the positioning energization angle setting unit 63 to initially set the positioning energization angle (θ = 0 °) (step S1), and this positioning energization angle θ. The positioning energization process is started using (Step S2). When the positioning energization process is performed, the detection unit 80 detects the two-phase currents of the U-phase current iu and the W-phase current iw of the synchronous motor M and outputs them to the three-phase to two-phase conversion unit 21. The three-phase to two-phase converter 21 converts the current vector component iu of the three-phase fixed coordinate system (UVW coordinate system) and the current iw of the W-phase into a current vector in the two-phase rotational coordinate system (γ-δ coordinate system). And the δ-axis current Iδ, which is the δ component, is output to the positioning determination processing unit 61. The positioning determination processing unit 61 monitors whether or not the δ-axis current Iδ is greater than or equal to a predetermined current value and continuously flows for a predetermined time after the start of positioning energization to determine whether or not the positioning has been performed (step S3). If it is determined by the positioning determination processing unit 61 that the δ-axis current Iδ is equal to or greater than a predetermined current value after the start of positioning energization and is continuously flowed for a predetermined time (Yes in step S3), the positioning control unit 62 determines In response to the result, start-up operation is started (step S6). When the start-up process is completed, the operation is shifted to steady operation. When the positioning determination processing unit 61 determines that the δ-axis current Iδ is greater than or equal to a predetermined current value and does not continuously flow for a predetermined time after the start of positioning energization (No in step S3), the positioning control unit 62 In response to the determination result, the positioning energization angle setting unit 63 is instructed to reset the positioning energization angle θ. The positioning energization angle setting unit 63 sets a new positioning energization angle θ obtained by adding a predetermined angle φ to the positioning energization angle θ (step S4). It is determined whether or not the positioning energization angle θ indicated by the positioning energization angle setting unit 63 is equal to or greater than 360 ° (when the synchronous motor has two poles) of one rotation of the rotor of the synchronous motor (step S5). If it is less than ° (No in step S5), the positioning energization angle θ is output to the 2-phase-3 phase converter 22 and the 3-phase-2 phase converter 21 and the process returns to step S2. The positioning control unit 62 repeats the positioning energization processing a predetermined number of times until the determination of the positioning determination processing unit 61 is positioned (Yes in Step S3) or until the positioning energization angle θ becomes 360 ° or more. The positioning control unit 62 determines that an error has occurred if the positioning determination processing unit 61 has not been positioned (No in step S3) and the positioning energization angle θ is 360 ° or more (Yes in step S5). Then, the activation process is stopped (step S7).

  As described above, in the present embodiment, the voltage setting unit 50 sets the voltage command for positioning energization before starting the synchronous motor M, and the two-phase to three-phase conversion unit 22 as the first conversion unit. The positioning energization voltage vector (voltage command) output from the voltage setting unit 50 on the two-phase γ-δ rotating coordinate system is converted into the positioning energization voltage vector in the three-phase UVW fixed coordinate system, and the driving unit 10 performs the first conversion. The synchronous motor M is driven by a voltage corresponding to the positioning energization voltage vector converted and output by the two-phase / three-phase conversion unit 22 as a unit, and driven by the three-phase / two-phase conversion unit 21 as a second conversion unit. The current vector in the three-phase UVW fixed coordinate system when driving the synchronous motor M from the unit 10 is converted into the current vector in the two-phase γ-δ rotating coordinate system, and the δ-axis current of the δ component of the converted current vector Iδ rank When in determining the determination processing unit 61 flows and continuous predetermined time at a predetermined current value or more, it determines that the rotor of the synchronous motor M is positioned, it is determined that otherwise not positioned. The positioning control unit 62 performs positioning energization for positioning the rotor of the synchronous motor M using the voltage set by the voltage setting unit 50, and when the positioning determination processing unit 61 determines that the rotor is positioned, the synchronous motor Start operation of. As a result, it is possible to determine whether or not the rotor has been positioned at a predetermined position after the energization of the positioning before starting the start-up operation, so that the synchronous motor can be started smoothly, the start-up success rate is improved, and vibration at start-up is also achieved. Can be reduced.

  In the present embodiment, when the positioning determination processing unit 61 determines that the rotor is not positioned, the positioning control unit 62 adds new positioning energization by adding a predetermined angle φ to the positioning energization angle θ at that time. Positioning energization is performed again with the positioning energization voltage vector generated using the angle θ, and the positioning determination processing unit 61 determines the positioning of the rotor of the synchronous motor M. As a result, even if it is determined that positioning is not performed by positioning energization, positioning energization is retried using a positioning energization voltage vector having a voltage phase φ that is a predetermined distance away, so that positioning can be performed reliably and synchronized. The startup success rate of the motor can be improved.

  In the present embodiment, the positioning control unit 62 determines that the rotor is positioned by the positioning determination processing unit 61 or sets the positioning energization angle θ set by the positioning energization angle setting unit 63 to a predetermined electrical angle. Repeat the positioning energization until. As a result, if the positioning energization angle is tried once and it is still not determined that the rotor is positioned, there is a possibility that the rotor is in a locked state. Therefore, it is possible to prevent positioning energization from being repeated more than necessary.

  In this embodiment, as a method for detecting the phase current, the three-phase phase current is calculated using two current sensors. However, the three-phase phase current is detected using three current sensors. Alternatively, a single shunt system that detects the bus current of the inverter may be used.

  As described above, the motor control device according to the present invention is useful for controlling a synchronous motor.

DESCRIPTION OF SYMBOLS 1 Motor control apparatus 10 Inverter 20 Generator 21 3-phase-2 phase converter 22 2-phase-3 phase converter 23 PWM generator 30 Current command generator 31 Position / speed estimator 32 Subtractor 33 d-axis current setter 34 q-axis current setting unit 35 subtractor 36 subtractor 37 1 / Pn converter 40 voltage command generation unit 50 voltage setting unit 51 δ (q) axis voltage setting unit 52 γ (d) axis voltage setting unit 60 positioning means 61 positioning determination Processing unit 62 Positioning control unit 63 Positioning energization angle setting unit 80 Detection unit 81 Current sensor 82 Current sensor

Claims (3)

A motor control device for controlling a synchronous motor having a rotor and a stator,
A voltage command generating unit that sets a positioning energization voltage for performing positioning energization for positioning the rotor and generates a voltage command before starting the synchronous motor;
A PWM generator that generates a three-phase PWM signal based on the voltage command output from the voltage command generator;
An inverter that converts DC power supplied from a DC power source into three-phase AC power by the PWM signal and supplies the AC power to the synchronous motor;
A detection unit for detecting a phase current flowing through the stator winding;
Based on the phase current of the synchronous motor detected by the detection unit, the three-phase phase currents (Iu, Iv, Iw) are calculated and converted into two-phase currents (Iγ, Iδ) in a rotating coordinate system -2 phase converter,
The δ-axis current Iδ is detected from the two-phase currents output from the three-phase to two-phase converter, and the rotor is positioned when the δ-axis current Iδ flows continuously for a predetermined time for a predetermined current value or more. A motor control apparatus comprising: a positioning determination processing unit that determines that the operation has been performed. When the positioning determination processing unit determines that the rotor is not positioned,
A positioning energization angle setting unit configured to add a predetermined angle φ to the positioning energization angle θ which is a phase of the positioning energization voltage to set a new energization angle θ and output the same to the voltage command generation unit;
The motor control device according to claim 1, wherein the positioning energization angle setting unit performs the positioning energization using a positioning energization angle θ newly set at the time of positioning energization.   When the positioning determination processing unit continues to determine that the rotor is not positioned, the positioning energization is repeatedly performed until the positioning energization angle θ set by the positioning energization angle setting unit reaches a predetermined angle. The motor control device according to claim 2.

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