JP2020036513A - Motor controller - Google Patents

Abstract

To apply a proper voltage to a motor when starting the motor.SOLUTION: A motor controller has a drive part for driving a motor by supplying the motor with a drive voltage generated based on the difference of a target speed and a current speed of the motor, and a detector for detecting a current flowing through the motor. The motor controller includes a speed estimation part for estimating the current speed from the d-axis current in the dq coordination system of the current detected by the detector, a d-axis voltage generation part for generating a d-axis drive voltage as the drive voltage of the d-axis in the dq coordination system, a q-axis voltage generation part for generating a q-axis drive voltage as the drive voltage of the q-axis in the dq coordination system, and a drive voltage generation part for generating drive voltage from the d-axis drive voltage and the q-axis drive voltage. When starting the motor, the d-axis voltage generation part outputs -ωe.Lq.Iq as the d-axis drive voltage, and the q-axis voltage generation part generates the q-axis drive voltage at least from the initial drive voltage, the target speed and the current speed after outputting the initial drive voltage.SELECTED DRAWING: Figure 9

Description

  The disclosed technology relates to a motor control device.

  Generally, a motor control device that drives and controls a motor by position sensorless vector control generates a d-axis current command value and a q-axis current command value such that the rotation speed of the motor becomes a speed command value (target speed). A d-axis voltage command value and a q-axis voltage command value are generated from the d-axis current command value and the q-axis current command value. Further, the motor control device converts the d-axis voltage command value and the q-axis voltage command value into a three-phase voltage command value, and a PWM (Pulse Width Modulation) generator performs PWM based on the three-phase voltage command value. A signal is generated and output to an IPM (Intelligent Power Module). The IPM controls the driving of the motor by applying three-phase voltages (U-phase voltage Vu, V-phase voltage Vv, and W-phase voltage Vw) to the motor by performing switching control according to the input PWM signal.

  When starting the motor, the motor control device operates the stopped motor in a range from zero speed to extremely low speed. At extremely low rotation speed, the induced voltage is extremely small, so that it is difficult to accurately detect the rotor position. Therefore, the motor control device performs control to increase the rotation speed of the motor so that the induced voltage can be increased to perform accurate position detection of the rotor. When the motor is started, the control for increasing the rotation speed of the motor while synchronizing the rotating magnetic field generated by the stator (stator) of the motor with the rotor is called "synchronous operation". After performing the synchronous operation of the motor, the motor control device shifts the mode to “normal operation”.

  However, in synchronous operation, the motor control device does not detect the rotor position, so that control may be difficult depending on the state of the motor load. Therefore, various techniques for performing start control according to the state of the load of the motor have been proposed.

  For example, there is a technique in which, when the load is small during synchronous operation of the motor, the rotational speed of the motor is increased so that the surplus power of the drive voltage of the motor is consumed by the increase in the rotational speed.

JP 2013-207868 A

  However, in the above-described technique, the q-axis voltage of the driving voltage is a predetermined value. For this reason, in the above-mentioned technology, while preventing excessive voltage from being applied to the motor when the load on the motor is small, it is appropriate to prevent the voltage applied to the motor from becoming insufficient when the load on the motor is large. Difficult to control.

  The disclosed technology has been made in view of the above, and has as its object to apply an appropriate voltage to a motor when the motor is started.

  In an aspect of the disclosure, a motor control device includes a drive unit, a detection unit, a speed estimation unit, a d-axis voltage generation unit, a q-axis voltage generation unit, and a drive voltage generation unit. The driving unit supplies a driving voltage generated based on a difference between a target speed of the motor and a current speed of the motor to the motor to drive the motor. The detection unit detects a current flowing through the motor. The speed estimating unit estimates the current speed from a d-axis current in a dq coordinate system of the current detected by the detecting unit. The d-axis voltage generation unit generates a d-axis drive voltage as the d-axis drive voltage in a dq coordinate system. The q-axis voltage generator generates a q-axis drive voltage as the q-axis drive voltage in the dq coordinate system. The drive voltage generation unit generates the drive voltage from the d-axis drive voltage and the q-axis drive voltage. Then, at the time of starting the motor, the d-axis voltage generator outputs a negative voltage as the d-axis drive voltage, and the q-axis voltage generator outputs an initial drive voltage. The q-axis drive voltage is generated from the initial drive voltage, the target speed, and the current speed.

  According to the aspect of the disclosure, an appropriate voltage can be applied to the motor when the motor is started. In particular, even when the load on the motor is large, the motor can be started while obtaining the required torque.

FIG. 1 is a diagram illustrating an example of a configuration of a motor control device during a normal operation according to the basic mode. FIG. 2A is a schematic diagram illustrating an example of a rotor positioning step according to the basic mode. FIG. 2B is a schematic diagram illustrating an example of a rotor positioning step according to the basic mode. FIG. 3 is a diagram illustrating an example of a configuration of a motor control device in a synchronous operation step according to the basic mode. FIG. 4 is a vector diagram showing a motor model equation in a steady state. FIG. 5 is a diagram illustrating an example of a configuration of a speed estimator (electrical angle) according to the basic mode. FIG. 6 is a diagram illustrating an example of a configuration of the motor control device in the synchronous operation step according to the first embodiment. FIG. 7 is a diagram illustrating an example of a configuration of the q-axis voltage generator in the synchronous operation step according to the first embodiment. FIG. 8 is a flowchart illustrating an example of a process of a synchronous operation step according to the first embodiment. FIG. 9 is a diagram illustrating an example of a configuration of a motor control device in a synchronous operation step according to the second embodiment. FIG. 10 is a diagram illustrating an example of a configuration of a d-axis voltage generator in a synchronous operation step according to the second embodiment. FIG. 11A is a diagram illustrating an example of changes in the d-axis current and the q-axis current according to the second embodiment when the load on the motor is large. FIG. 11B is a diagram illustrating an example of transition of the d-axis current and the q-axis current according to the first embodiment when the load of the motor is large. FIG. 12A is a diagram illustrating an example of transition of the d-axis voltage and the q-axis voltage according to the second embodiment when the load on the motor is large. FIG. 12B is a diagram illustrating an example of changes in the d-axis voltage and the q-axis voltage according to the first embodiment when the load on the motor is large. FIG. 13A is a diagram illustrating an example of a transition of an axis error according to the second embodiment when the load on the motor is large. FIG. 13B is a diagram illustrating an example of a transition of the axis error according to the first embodiment when the load of the motor is large. FIG. 14A is a diagram illustrating an example of transitions of the estimated electric angle speed and the target electric angle speed according to the second embodiment when the motor load is large. FIG. 14B is a diagram illustrating an example of changes in the estimated electric angle speed and the target electric angle speed according to the first embodiment when the load on the motor is large. FIG. 15 is a diagram illustrating an example of an ideal relationship between a current vector on the dq axis and a current vector on the γδ axis. FIG. 16 is a diagram illustrating an example of the relationship between the dq-axis current vector and the γδ-axis current vector according to the first embodiment. FIG. 17 is a diagram illustrating an example of a relationship between a dq-axis current vector and a γδ-axis current vector according to the second embodiment.

  Hereinafter, basic modes, embodiments, and modifications of a motor control device according to the disclosed technology of the present application will be described in detail with reference to the drawings. The disclosed technology is not limited by the following basic modes, embodiments, and modified examples. The motor control device shown in the following basic modes, embodiments, and modifications will be described as a control device for a motor loaded with a propeller fan, a refrigerant, or the like used in an air conditioner or the like. Applicable to the control of The following basic modes, embodiments, and modified examples can be implemented in appropriate combinations within a consistent range.

  In the following basic modes, embodiments, and modifications, configurations and processes according to the disclosed technology are mainly described, and descriptions of other configurations and processes are appropriately simplified or omitted. In the following basic modes, embodiments, and modifications, the same reference numerals are given to the same configurations and processes, and the description of the already-described configurations and processes will be omitted.

[Basic form]
(Motor control device during normal operation according to basic mode)
Prior to the description of the embodiment, a basic mode which is a premise will be described. FIG. 1 is a diagram illustrating an example of a configuration of a motor control device during a normal operation according to the basic mode. FIG. 1 shows a general basic configuration of motor position sensorless vector control by a motor control device during normal operation.

  The normal operation refers to a mode in which the motor is drive-controlled by controlling the current and the voltage so that the rotation speed of the motor is appropriate based on the rotor position fed back by the position sensorless vector control. FIG. 1 shows only components of the microcomputer included in the motor control device according to the basic mode during normal operation of the motor.

  The motor control device 100X according to the basic mode during normal operation includes a microcomputer 10X, an IPM (Intelligent Power Module) 23, switches SW1, and a 3φ current calculator 24. The motor 1 is connected to the motor control device 100X.

  The microcomputer 10X includes a controller 2X, a subtractor 11, a speed controller 12, an exciting current controller 13, a subtractor 14, a subtractor 15, a d-axis current controller 16, a q-axis current controller 17, Controller 18, subtractor 19, adder 20, dq / 3φ converter 21, PWM (Pulse Width Modulation) generator 22, 3φ / dq converter 25, axis error calculation processor 26, PLL controller 29, position It has an estimator 30 and a 1 / Pn processor 31.

The subtractor 11 calculates the current rotational speed (mechanical angle) of the motor 1 as an estimated value output by the 1 / Pn processor 31 from the speed command value (mechanical angle target speed) ω ^* input to the motor control device 100X. A speed deviation (mechanical angular speed deviation) Δω obtained by subtracting the estimated speed ω is output to the speed controller 12.

The speed controller 12 generates a q-axis current command value Iq ^* such that the speed deviation Δω output by the subtractor 11 becomes smaller, and outputs the generated q-axis current command value Iq ^* to the excitation current controller 13 and the subtractor 15. The exciting current controller 13 generates a d-axis current command value Id ^* from the q-axis current command value Iq ^* output by the speed controller 12 and outputs the same to the subtractor 14. The d-axis and the q-axis represent coordinate axes of a two-phase rotating coordinate system (current vector coordinates), and Id and Iq, and Vd and Vq described later indicate current and voltage on the coordinate axes. The two-phase rotation coordinate system is also called a dq coordinate system.

The subtractor 14 subtracts the d-axis current Id output by the 3φ / dq converter 25 from the d-axis current command value Id ^* output by the excitation current controller 13 to generate a d-axis current deviation ΔId, Output to the shaft current controller 16. The subtractor 15 subtracts the q-axis current Iq output by the 3φ / dq converter 25 from the q-axis current command value Iq ^* output by the speed controller 12 to generate a q-axis current deviation ΔIq, Output to the current controller 17.

The d-axis current controller 16 generates a d-axis voltage command value Vd ^** from the d-axis current deviation ΔId output from the subtractor 14. The q-axis current controller 17 generates a q-axis voltage command value Vq ^** from the q-axis current deviation ΔIq output from the subtractor 15.

The decoupling controller 18 cancels interference between the d-axis and the q-axis, and generates a decoupling correction value for controlling each of them independently. Specifically, the decoupling controller 18 determines the d-axis voltage command value Vd ^* from the d-axis current Id output from the 3φ / dq converter 25 and the estimated electrical angle ωe output from the PLL controller 29 ^. A d-axis decoupling correction value Vda for decoupling ^* is generated and output to the subtractor 19. Further, the decoupling controller 18 determines the q-axis voltage command value Vq ^** from the q-axis current Iq output from the 3φ / dq converter 25 and the estimated electrical angle ωe output from the PLL controller 29. A q-axis decoupling correction value Vqa for causing interference is generated and output to the adder 20.

The subtractor 19 subtracts the d-axis decoupling correction value Vda output by the decoupling controller 18 from the d-axis voltage command value Vd ^** output by the d-axis current controller 16 to obtain a d-axis voltage. A d-axis voltage command value Vd ^*, which is made the command value Vd ^** non-interfering, is generated and output to the dq / 3φ converter 21. The adder 20 adds the q-axis decoupling correction value Vqa output by the decoupling controller 18 to the q-axis voltage command value Vq ^** output by the q-axis current controller 17 to generate a q-axis voltage. A q-axis voltage command value Vq ^{* in} which the command value Vq ^** is made non-interfering is generated and output to the dq / 3φ converter 21.

The dq / 3φ converter 21 uses the electrical angle phase (dq-axis phase) θe, which is the current rotor position, output from the position estimator 30 to make the two-phase d-axis voltage command value Vd decoupling. ^{* And the} q-axis voltage command value Vq ^* are converted into three-phase voltage command values: a U-phase output voltage command value Vu ^* , a V-phase output voltage command value Vv ^* , and a W-phase output voltage command value Vw ^* . Then, the dq / 3φ converter 21 outputs the U-phase output voltage command value Vu ^* , the V-phase output voltage command value Vv ^* , and the W-phase output voltage command value Vw ^* to the PWM generator 22. The U-phase output voltage command value Vu ^* , V-phase output voltage command value Vv ^* , W-phase output voltage command value Vw ^*, and U-phase current Iu, V-phase current Iv, and W-phase current Iw, which will be described later, are fixed at three phases. These are the voltage and current of the coordinate system.

The PWM generator 22 generates a six-phase PWM signal from the U-phase output voltage command value Vu ^* , the V-phase output voltage command value Vv ^* , the W-phase output voltage command value Vw ^*, and the PWM carrier signal, and sends the PWM signal to the IPM 23. Output. The PWM generator 22 is an example of a signal generator. Note that the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* may be voltage command values, and the dq / 3φ converter 21 may be included in the signal generator.

  The IPM 23 generates an AC voltage to be applied to each of the U-phase, V-phase, and W-phase of the motor 1 from a DC voltage Vdc supplied from the outside based on the six-phase PWM signal output from the PWM generator 22. Then, the respective AC voltages are applied to the U, V, and W phases of the motor 1. The IPM 23 is an example of a drive unit that drives a motor by supplying a drive voltage generated based on a difference between a target speed and a current speed of the motor to the motor. The IPM 23 may be, for example, an IC (Integral Circuit) in which transistors and diodes are integrated, or may have a configuration in which respective components are arranged on a circuit board.

  The switch SW1 has a contact point CO0, a contact point CO1, and a contact point CO2. The switch SW1 switches the connection between the contact points CO0 and CO1 and the connection between the contact points CO0 and CO2 under the control of the controller 2X.

  When the contact point CO0 of the switch SW1 is connected to the contact point CO1, the 3φ current calculator 24 calculates the six-phase PWM switching information output by the PWM generator 22 and the shunt resistance (FIG. The bus current is detected using the bus current, and the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw of the motor 1 are calculated from the bus current. Then, the 3φ current calculator 24 outputs the calculated U-phase current Iu, V-phase current Iv, and W-phase current Iw of the motor 1 to the 3φ / dq converter 25.

  Alternatively, when the contact CO0 of the switch SW1 is in a state of being connected to the contact CO2, the 3φ current calculator 24 detects the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw of the motor 1 by the 2CT current detection method. Two phase currents are detected by two CTs (Current Transformers), and the currents of the remaining phases are calculated from Kirchhoff's law relational expression Iu + Iv + Iw = 0.

  The current detection may use only one of the one shunt current detection method, the 2CT current detection method, and the like. In this case, a detection circuit other than the current detection method and the switch SW1 can be omitted. The 3φ current calculator 24 is an example of a detection unit that detects a current flowing through the motor.

  The 3φ / dq converter 25 uses the electrical angle phase θe output from the position estimator 30 to output the three-phase U-phase current Iu, V-phase current Iv, and W-phase current Iw output from the 3φ current calculator 24. Into a two-phase d-axis current Id and a q-axis current Iq. The 3φ / dq converter 25 outputs the d-axis current Id to the subtractor 14, the decoupling controller 18, and the axis error calculation processor 26, and the q-axis current Iq to the subtractor 15, the decoupling controller 18, The data is output to the axis error calculation processor 26.

The axis error arithmetic processing unit 26 outputs the d-axis voltage command value Vd ^* output by the subtractor 19 and the q-axis voltage command value Vq ^* output by the adder 20, and d output by the 3φ / dq converter 25. An axis error Δθ is calculated from the axis current Id and the q-axis current Iq and output to the PLL controller 29. Here, the axis error Δθ is a deviation between an actual dq axis and a control dq axis (γδ axis).

  The PLL controller 29 calculates the estimated electric angular speed ωe, which is the estimated current angular speed of rotation of the motor 1, from the axis error Δθ output from the axis error calculation processor 26. Output to the position estimator 30 and the 1 / Pn processor 31 respectively.

  The position estimator 30 calculates an electrical angle phase (dq-axis phase) θe for estimating the rotor position from the estimated electrical angle speed ωe output from the PLL controller 29. Then, position estimator 30 outputs electrical angle phase θe to dq / 3φ converter 21 and 3φ / dq converter 25, respectively.

  The 1 / Pn processor 31 divides the estimated electrical angle speed ωe output from the PLL controller 29 by the number of pole pairs Pn of the motor 1 to calculate the current rotational speed ω of the motor 1 and outputs the current rotational speed ω to the subtractor 11. .

(Motor start control according to basic mode)
During normal operation of the motor 1, a sufficient induced voltage is generated in the motor 1, and therefore, the motor control device 100X drives the motor 1 by position feedback control for calculating an axis error. However, when the motor 1 is started, the motor 1 is in a very low rotation state, and a sufficient induced voltage is not generated, so that an axis error cannot be calculated (an axis error cannot be detected). The device 100X cannot start the motor 1 using the control method of the normal operation.

  Therefore, the motor control device 100X starts the motor 1 by start control different from the normal operation. In the startup control of the motor 1, the motor control device 100X first executes a rotor positioning step of adjusting an initial rotor (rotor) position, and secondly, performs a synchronous operation of accelerating the motor 1 until the position can be detected. Steps are executed, and then the mode shifts to a normal operation in which the motor 1 is driven by the position sensorless vector control.

(Rotor positioning according to basic form)
2A and 2B are schematic diagrams illustrating an example of a rotor positioning step according to the basic mode. As shown in FIGS. 2A and 2B, the rotor positioning is performed by applying a voltage (current) in the d-axis direction of the dq-axis coordinate system to thereby control the rotor position on the control side (γδ coordinate system) and the actual rotor position (dq coordinate system). System). At this time, as shown in FIGS. 2A and 2B, since the rotor moves to the predetermined position (the position on the control side), a torque larger than the load torque under the operating environment is generated. By setting the voltage at this time as the initial q voltage V0 (q-axis voltage) in the synchronous operation step, it is possible to generate a driving torque.

(Configuration of motor control device in synchronous operation step according to basic mode)
FIG. 3 is a diagram illustrating an example of a configuration of a motor control device in a synchronous operation step according to the basic mode. In the synchronous operation step, unlike the normal operation, the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* are generated without using the d-axis current command value Id ^* and the q-axis current command value Iq ^*. Means a mode in which the motor is drive-controlled.

  The motor control device 100X in the synchronous operation step according to the basic mode has a microcomputer 10X, an IPM 23, switches SW1, and a 3φ current calculator 24.

  The microcomputer 10X includes a d-axis voltage generator 16X, a q-axis voltage generator 17X, a dq / 3φ converter 21, a PWM generator 22, an IPM 23, switches SW1, 3φ current calculator 24 including contacts CO0 to CO1, It has a 3φ / dq converter 25, a speed estimator 29X, and a position estimator 30X. The microcomputer 10X has a d-axis voltage generator 16X, a q-axis voltage generator 17X, a dq / 3φ converter 21, a PWM generator 22, an IPM 23, and a controller 2X.

  The controller 2X controls the switch SW1 including the contacts CO0 to CO1 and the entire microcomputer 10X, and also controls, for example, a mode transition of the motor 1 from the synchronous operation step to the normal operation.

  Note that FIG. 3 shows only the configuration of the microcomputer included in the motor control device according to the basic mode in the synchronous operation step of the motor.

The d-axis voltage generator 16X generates a d-axis voltage command value Vd ^* in the synchronous operation step, and outputs it to the dq / 3φ converter 21. The q-axis voltage generator 17X generates a q-axis voltage command value Vq ^* in the synchronous operation step, and outputs it to the dq / 3φ converter 21.

The dq / 3φ converter 21 uses the electrical angle phase θe, which is the rotor position output from the position estimator 30X, to output the d-axis voltage command value Vd ^* and the q-axis voltage output from the d-axis voltage generator 16X. The q-axis voltage command value Vq ^* output by the generator 17X is converted into a U-phase output voltage command value Vu ^* , a V-phase output voltage command value Vv ^* , and a W-phase output voltage command value Vw ^* , and the PWM generator 22 Output.

  The PWM generator 22, the IPM 23, and the 3φ current calculator 24 are the same as those of the motor control device 100X during normal operation according to the basic mode.

  The 3φ / dq converter 25 uses the electrical angle phase θe output from the position estimator 30X to output the three-phase U-phase current Iu, V-phase current Iv, and W-phase current Iw output from the 3φ current calculator 24. Into a two-phase d-axis current Id and a q-axis current Iq. Then, the 3φ / dq converter 25 outputs the d-axis current Id to the speed estimator 29X.

  The speed estimator 29X calculates the estimated electric angular speed ωe, which is the current angular speed of the motor, from the d-axis current Id output from the 3φ / dq converter 25, and outputs the calculated electrical angle to the position estimator 30X.

  The position estimator 30X calculates an electrical angle phase (dq-axis phase) θe for estimating the rotor position from the estimated electrical angle speed ωe output from the speed estimator 29X, and outputs the dq / 3φ converter 21 and the 3φ / dq conversion. Output to the devices 25 respectively.

Here, the d-axis voltage command value Vd ^* generated by the d-axis voltage generator 16X and the q-axis voltage command value Vq ^* generated by the q-axis voltage generator 17X will be described. Hereinafter, the respective d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^*, replaced respectively d-axis voltage Vd ^* and the q-axis voltage Vq ^*.

First, the d-axis voltage Vd ^* generated by the d-axis voltage generator 16X will be described. The d-axis voltage Vd ^* generated by the d-axis voltage generator 16X is given by the following equation (1) from the dq-axis motor model equation in normal operation. In the right side of the following equation (1), “R” is the winding resistance of the motor 1, “Id” is the d-axis current of the motor 1, “ω” is the estimated electric angle speed of the motor 1, and “Lq” is the motor. 1, “Iq” is the q-axis current of the motor 1, “ρ” is a differential operator of (d / dt), and “Ld” is the d-axis inductance of the motor 1.

Since the third term on the right side of the above equation (1) can be regarded as 0 in the steady state, the equation (1) becomes the following equation (2) in the steady state.

  The d-axis voltage Vd expressed by the above equation (2) is as shown in the vector diagram of FIG. FIG. 4 is a vector diagram showing a motor model equation in a steady state. In the above equation (2), the first term on the right side is term2-1 in FIG. 4, and the second term on the right side is term2-2 in FIG. Here, “Ψ” shown in FIG. 4 is a linkage magnetic flux of the motor 1.

From the above equation (2), it can be seen that the d-axis voltage Vd becomes negative when the d-axis current Id flows in the negative direction and the q-axis current Iq flows in the positive direction. However, the d-axis current Id immediately after the start of the motor 1 flows in the positive direction. This is because the initial q-axis voltage V0 in the synchronous operation step generates a driving torque, and the d-axis voltage Vd ^* immediately after the start of the motor 1 is not an optimum voltage. The optimal voltage is a voltage that creates an optimal state, and the optimal state is a state in which surplus power is small. Immediately after the shift to the synchronous operation step, the voltage is momentarily excessive. Therefore, the d-axis voltage Vd ^* immediately after the start of the motor 1 is generated in the positive direction on the d-axis side, with the surplus power other than the power necessary for the rotation of the motor 1 as an ineffective component.

In order to operate the motor with high efficiency considering not only the magnet torque but also the reluctance torque, generally, the d-axis voltage Vd ^* is adjusted so that the d-axis current Id is generated in the negative direction. However, immediately after the motor 1 is started, it is preferable that the current vectors (the d-axis current Id and the q-axis current Iq) be in the first quadrant of the current vector coordinates. This is because if the current vector is in the first quadrant, the margin for the increase and decrease of the load of the motor 1 and the increase of the rotation speed increases. Therefore, the d-axis current Id is controlled in the positive direction using the d-axis current Id generated in the positive direction on the d-axis immediately after the start of the motor 1. In this case, the current vectors (the d-axis current Id and the q-axis current Iq) are both in the positive direction of the d-axis current Id and the q-axis current Iq, that is, in the first quadrant of the current vector coordinates.

Therefore, in the above equation (2), in order to set both the d-axis current Id and the q-axis current Iq in the positive direction, since the q-axis current Iq is positive, the d-axis voltage Vd is set to 0 and the d-axis current Id Is also positive. This can also be understood from the fact that Vd = 0 in the above equation (2) and the equation is modified as in the following equation (3). That is, since the q-axis current Iq flows in the positive direction, the d-axis current Id also flows in the positive direction from the above equation (3), and the current vector (the d-axis current Id and the q-axis current Iq) is expressed by the current vector coordinates. Can be kept in the first quadrant.

Returning to FIG. 3, the q-axis voltage Vq ^* generated by the q-axis voltage generator 17X will be described. The q-axis voltage generator 17X generates a driving torque by setting the q-axis voltage having the same magnitude as the d-axis voltage at the time of positioning in the rotor positioning step as the initial q-axis voltage V0. The surplus power generated at this time is consumed as power required for rotation of the load connected to the motor 1 as the rotation speed of the motor 1 increases, so that the surplus power gradually becomes zero. The d-axis current Id gradually goes from the positive direction to the negative direction.

The speed estimator 29X is based on the idea of setting the d-axis current Id to 0, and can be realized by the configuration shown in FIG. 5 described later. That is, the q-axis drive voltage Vq ^* output by the q-axis voltage generator 17X generates surplus power. Since the reactive component (surplus power) is eliminated by increasing the rotation speed of the motor 1, the d-axis current Id goes from the positive direction to the negative direction. That is, as the rotational speed ω of the motor 1 increases, the d-axis current Id goes from the positive direction to the negative direction, and the d-axis current Id becomes zero. In other words, the estimated electric angle ωe as the current speed of the motor 1 estimated by the speed estimator 29X is a speed at which the d-axis current Id becomes zero.

(Configuration of speed estimator (electrical angle) according to basic mode)
FIG. 5 is a diagram illustrating an example of a configuration of a speed estimator (electrical angle) according to the basic mode. The speed estimator 29X includes a proportional term calculation processor 29X-1 and an integral term calculation processor 29X-2, a proportional term calculation processor 29X-1, and an integral term calculation process which are connected in parallel to the input of the d-axis current Id. The adder 29X-3 adds the processing results of the respective units 29X-2. The speed estimator 29X calculates the d-axis current Id by using the characteristic that the axis error Δθ decreases as the speed of the motor 1 increases, the surplus power is converted into torque, and the d-axis current Id becomes zero. Speed estimation is performed by processing with integral proportional control (PI control). When the d-axis current Id becomes 0, the estimated electric angle ωe of the motor 1 at the given q-axis voltage Vq is obtained.

Specifically, the speed estimator 29X calculates the estimated electrical angle ωe of the motor 1 by performing proportional-integral control (PI control) on the d-axis current Id based on the following equation (4). In the following equation (4), “Kp” is a proportional gain, and “Ki” is an integral gain. The integral section on the right side of the following equation (4) is the time from the start of the synchronous operation step of the motor 1 to the present.

  However, in the motor control device 100X in the synchronous operation step according to the basic configuration shown in FIG. 3, the current vectors (the d-axis current Id and the q-axis current Iq) are in the first quadrant of the current vector coordinates. Although a margin for the load of the motor 1 is ensured, the rotation speed ω of the motor 1 varies depending on the load. For this reason, even if the mode transition from the synchronous operation step to the normal operation is performed normally, the rotational speed ω of the motor 1 may not be fast enough to calculate the axis error Δθ. In order to solve this problem, it is preferable to increase the rotation speed ω of the motor 1 to a rotation speed sufficient to calculate the axis error Δθ while coping with the load under the operating environment.

[Embodiment 1]
(Configuration of Motor Control Device in Synchronous Operation Step According to First Embodiment)
Therefore, in the first embodiment, a speed command type configuration shown in FIG. 6 is used instead of the configuration of the motor control device in the synchronous operation step according to the basic mode of FIG. FIG. 6 is a diagram illustrating an example of a configuration of the motor control device in the synchronous operation step according to the first embodiment.

  The motor control device 100A in the synchronous operation step according to the first embodiment has a microcomputer 10A instead of the microcomputer 10X in the basic mode. The microcomputer 10A has a controller 2A in place of the controller 2X in the basic mode, has a q-axis voltage generator 17A in place of the q-axis voltage generator 17X in the basic mode, and performs speed estimation in the basic mode. A speed estimator 29A is provided in place of the device 29X. The configuration of the motor control device 100A in the synchronous operation step according to the first embodiment is the same as the motor control device 100X according to the basic mode, except for the controller 2A, the q-axis voltage generator 17A, and the speed estimator 29A.

  The controller 2A controls the switch SW1 including the contacts CO0 to CO1 and the entire microcomputer 10A, and also controls, for example, the mode transition of the motor 1 from the synchronous operation step to the normal operation.

The q-axis voltage generator 17A outputs the d-axis current Id output from the 3φ / dq converter 25, the estimated electric angle speed ωe output from the speed estimator 29A, the electric angle initial speed ωe0 of the motor 1, and q A q-axis voltage command value Vq ^* in the synchronous operation step is generated from the electric angular velocity command value ωe ^* generated inside the shaft voltage generator 17A and the initial q-axis voltage V0, and output to the dq / 3φ converter 21. I do.

  The q-axis voltage generator 17A sets the initial q-axis voltage V0 to the same q-axis voltage as the d-axis voltage at the time of positioning in the rotor positioning step, similarly to the q-axis voltage generator 17X of the basic mode. , Generating a driving torque. The surplus electric power generated at this time is used as electric power necessary for the rotation of the actual load connected to the motor 1 as the rotation speed of the motor 1 increases, so that there is no reactive component (excess electric power).

  Here, if the q-axis voltage generator 17A can generate an appropriate q-axis voltage Vq for increasing the speed of the motor 1 while controlling the surplus power to a minimum, the calculation of the axis error Δθ is performed. , It is possible to secure a speed sufficient to generate an induced voltage necessary for the operation, and it is possible to shift the mode from the synchronous operation step to the normal operation.

  The speed estimator 29A has the same configuration as that of the speed estimator 29X according to the basic mode. However, based on the d-axis current Id output from the 3φ / dq converter 25, the electric angle which is the current angular speed of the motor estimated. The estimated speed ωe is calculated and output to the q-axis voltage generator 17A and the position estimator 30X. The speed estimator 29A is an example of a speed estimating unit that estimates the current speed from the d-axis current in the dq coordinate system of the current detected by the detecting unit.

Here, the q-axis voltage Vq generated by the q-axis voltage generator 17A will be described. Hereinafter, the q-axis voltage command value Vq ^* is replaced with the q-axis voltage Vq. The q-axis voltage Vq generated by the q-axis voltage generator 17A is given by the following equation (5) from the dq-axis motor model equation in normal operation. In the right side of the following equation (5), “ωe” is the electrical angular velocity, “Lq” is the q-axis inductance of the motor 1, “Id” is the d-axis current, “R” is the winding resistance of the motor 1, “Iq ”Is the q-axis current,“ Ψ ”is the flux linkage of the motor 1,“ ρ ”is the differential operator of (d / dt), and“ Ld ”is the d-axis inductance of the motor 1.

The fourth term on the right side of the above equation (5) can be regarded as 0 in the steady state, so that in the steady state, the above equation (5) becomes the following equation (6).

  The q-axis voltage Vq expressed by the above equation (6) is as shown in the vector diagram of FIG. In the above expression (6), the first term on the right side is term 6-1 in FIG. 4, the second term on the right side is term 6-2 in FIG. 4, and the third term on the right side is term 6-3 in FIG.

From the initial q-axis voltage V0 immediately after the start of the motor 1 after completion of the rotor positioning step, the initial electric angular velocity ωe0 generated by the initial q-axis voltage V0, and the electric angular velocity command value ωe ^* , the q-axis voltage Vq is It is expressed by equation (7).

  The equation (7) includes a term including the q-axis current Iq. As in the basic mode, the speed estimator 29A calculates the estimated electrical angle speed ωe such that the d-axis current Id becomes zero. Further, if the speed of the motor 1 is increased by the q-axis voltage Vq, the reactive component, which is surplus power, disappears, and the d-axis current Id goes to zero. That is, it can be said that the q-axis voltage Vq and the d-axis current Id have a close relationship with the speed of the motor 1 in the synchronous operation step. To control the speed of the rotor by controlling the q-axis voltage Vq while setting the d-axis current Id to 0, in order to calculate the q-axis voltage Vq to be applied to the motor 1 from the commanded speed of the rotor, The q-axis current Iq is converted to speed.

In order to convert the q-axis current Iq into a speed, the q-axis current Iq is represented using the torque T of the motor 1 and the flux linkage Ψ, as shown in the following equation (8).

Further, as shown in the following equation (9), the torque T of the motor 1 is expressed by using the inertia J of the motor 1 and the acceleration a.

In the above equation (9), the acceleration a is an angular acceleration. As shown in the following equation (10), the angular acceleration a is represented by using the electric angular velocity command value ωe ^* and the estimated electric angular velocity ωe.

That is, the angular acceleration is represented by a speed deviation, and a q-axis voltage required for the electric angular velocity command value ωe ^* is generated by integrating the speed deviation. From the above equations (8) to (10), the q-axis current Iq is as shown in the following equation (11). The integral section on the right side of the following equation (11) is the time from the start of the synchronous operation step of the motor 1 to the present.

By substituting the above equation (11) into “Iq” in the second term on the right side of the above equation (7), the q-axis voltage Vq becomes the q-axis current Iq as shown in the following equation (12). It is expressed without including the factor of Note that “Kc” in the following equation (12) is an integral gain adjustment coefficient and is a specific constant. The q-axis voltage generator 17A generates and outputs a q-axis voltage (q-axis drive voltage) Vq ^{* according} to the following equation (12).

(Q-axis voltage generator in synchronous operation step according to Embodiment 1)
FIG. 7 is a diagram illustrating an example of a configuration of the q-axis voltage generator in the synchronous operation step according to the first embodiment. The q-axis voltage generator 17A in the synchronous operation step according to the first embodiment includes an Ld multiplier 17A-1, a subtractor 17A-2, an integrator 17A-3, a subtractor 17A-4, a Ψ multiplier 17A-5, and an adder. 17A-6, an adder 17A-7, and an electric angular velocity command generator 17A-8.

The electric angular velocity command generator 17A-8 generates an electric angular velocity command value ωe ^* in a synchronous operation step when the motor is started, and uses the generated electric angular velocity command value ωe ^* as an Ld multiplier 17A-1 and a subtractor 17A. -2, output to each of the subtractors 17A-4.

The Ld multiplier 17A-1 receives the d-axis current Id and the electric angular velocity command value ωe ^* , and outputs the result of multiplying the two inputs by the d-axis inductance Ld to the adder 17A-6. The second term on the right side in the above equation (12) corresponds to the operation result by the Ld multiplier 17A-1.

The subtractor 17A-2 receives the electric angular velocity command value ωe ^* and the estimated electric angular velocity ωe, and outputs a result obtained by subtracting the estimated electric angular velocity ωe from the electric angular velocity command value ωe ^* to the integrator 17A-3. The integrand of the third term on the right side in the above equation (12) corresponds to the operation by the subtractor 17A-2.

  Integrator 17A-3 outputs the result of integrating the input from subtractor 17A-2 to adder 17A-6. The integration of the third term on the right side in the above equation (12) corresponds to the calculation by the integrator 17A-3.

The subtractor 17A-4 receives the electric angular velocity command value ωe ^* and the electric angular initial velocity ωe0, and outputs the result of subtracting the electric angular initial velocity ωe0 from the electric angular velocity command value ωe ^* to the Ψ multiplier 17A-5. The first factor of the first term on the right side in the above equation (12) corresponds to the operation by the subtractor 17A-4.

  {Multiplier 17A-5 outputs the result of multiplying the input from subtractor 17A-4 by the flux linkage モ ー タ of motor 1 to adder 17A-6. The first term on the right side in the above equation (12) corresponds to the operation by the Ψ multiplier 17A-5.

  The adder 17A-6 outputs the result of adding the outputs from the Ld multiplier 17A-1, the integrator 17A-3, and the Ψ multiplier 17A-5 to the adder 17A-7. The addition of the first to third terms on the right side in the above equation (12) corresponds to the operation by the adder 17A-6.

  The adder 17A-7 receives the output from the adder 17A-6 and the initial q-axis voltage V0, and outputs the result of adding the two inputs as a q-axis voltage Vq. The addition of the fourth term on the right side in the above equation (12) corresponds to the operation by the adder 17A-7.

(Process of synchronous operation step according to Embodiment 1)
FIG. 8 is a flowchart illustrating an example of a process of a synchronous operation step according to the first embodiment. The process of the synchronous operation step according to the first embodiment is executed by the controller 2A when the start of the motor 1 is triggered.

The q-axis voltage generator 17A calculates a q-axis voltage (q-axis drive voltage) Vq ^* using a deviation between the electric angular velocity command value ωe ^* generated by the electric angular velocity command generator 17A-8 and the estimated electric angular velocity ωe ^. Generate. For this reason, in the synchronous operation step, the electric angle estimation speed ωe performs feedback path (feedback) control, and forms a closed loop. Here, a difference occurs between the generation of the q-axis voltage (q-axis drive voltage) Vq ^* and the response speed of the rotation speed. That is, surplus power may be generated in the q-axis voltage even when the rotation speed reaches the target attainment speed, which is the speed at which the normal operation can be shifted from the synchronous operation. In that case, by providing a convergence time for converging to an appropriate q-axis voltage with respect to the rotation speed, it is possible to shift to a seamless normal operation with less shock at the time of switching.

  Here, the convergence time is obtained from the input and output of the q-axis voltage generator 17A and the speed estimator 29A. That is, the convergence time is obtained by solving the above equation (12) showing the relationship between the d-axis current Id as the input of the q-axis voltage generator 17A and the speed estimator 29A and the q-axis voltage Vq as the output with respect to the convergence time. Ask by that. Therefore, the convergence time can be obtained from the respective constants given by the above equation (12) by calculation with a small amount of calculation.

In the motor control device 100A in the synchronous operation step according to the first embodiment, first, in step S11, the controller 2A increases the electric angular velocity command value ωe ^* generated by the electric angular velocity command generator 17A-8, It is determined whether or not the electric angular velocity command value ωe ^* has reached a predetermined target arrival speed. The controller 2A moves the process to step S12 in the case of step S11: Yes, that is, when the electric angular velocity command value ωe ^* has reached a predetermined target arrival speed. On the other hand, in the case of step S11: No, that is, when the electric angular velocity command value ωe ^* has not reached the predetermined target attainment speed, the controller 2A shifts the processing to step S15.

  In step S12, the controller 2A determines whether or not the above-described convergence time has elapsed. The controller 2A moves the process to step S13 in the case of step S12: Yes, that is, when the convergence time has elapsed. On the other hand, the controller 2A moves the process to step S16 in the case of step S12: No, that is, when the convergence time has not elapsed.

  In step S13, the controller 2A determines whether or not the estimated electrical angle speed ωe has reached the target arrival speed as in step S11. Step S13 determines whether or not the motor 1 has reached a speed at which the axis error Δθ can be calculated. The controller 2A moves the process to step S14 in the case of step S13: Yes, that is, in the case where the estimated electrical angle speed ωe has reached the target arrival speed. On the other hand, in the case of step S13: No, that is, when the estimated electrical angle speed ωe has not reached the target arrival speed, the controller 2A shifts the processing to step S17.

  In step S14, the controller 2A executes a mode transition process from the synchronous operation step to the normal operation.

In step S15, the controller 2A controls the q-axis voltage generator 17A to start or continue to execute the generation processing of the q-axis voltage (q-axis drive voltage) Vq ^* . When the processing in step S15 ends, the controller 2A shifts the processing to step S11. In step S16, the controller 2A controls the q-axis voltage generator 17A to continuously execute the generation processing of the q-axis voltage (q-axis drive voltage) Vq ^* . When the processing in step S16 ends, the controller 2A moves the processing to step S12.

In step S17, the controller 2A switches the mode because the electric angular velocity command value ωe ^* has reached the target arrival speed and the estimated electric angle ωe has not reached the target arrival speed even after the convergence elapsed time has elapsed. Error processing (for example, motor start / stop, motor start re-execution, error notification, etc.) when an impossible error occurs is executed. When step S17 ends, the controller 2A ends the process of the synchronous operation step according to the first embodiment.

According to the first embodiment, the q-axis voltage (q-axis drive voltage) Vq ^* is controlled according to the difference between the electric angular velocity command value ωe ^* and the estimated electric angular velocity ωe. Therefore, a q-axis voltage (q-axis drive voltage) Vq ^* according to the load state of the motor 1 can be obtained. Further, according to the first embodiment, by obtaining the q-axis voltage (q-axis drive voltage) Vq ^* according to the state of the load of the motor 1, it is possible to suppress an excessive voltage (overcurrent).

  Further, according to the first embodiment, by fixing the d-axis voltage to 0 and controlling only the q-axis voltage, the speed of the motor 1 can be easily controlled, and the surplus power can be suppressed. In addition, since the current vector can be kept in the first quadrant of the current vector coordinates, it is possible to increase the margin for the load fluctuation of the motor 1 and the acceleration fluctuation of the motor 1.

Further, according to the first embodiment, the electric angle estimation speed ωe sets the d-axis current Id of the motor 1 to 0, and the q-axis voltage (q-axis drive voltage) Vq ^* so that the d-axis current does not excessively occur in the positive direction ^. , The generation of surplus power can be suppressed. Further, the speed at which the motor 1 can be rotated can be secured only by the q-axis voltage (q-axis drive voltage) Vq ^* . Furthermore, according to the first embodiment, the q-axis voltage (q-axis drive voltage) Vq ^* can be easily generated from the above equation (12).

  Further, according to the first embodiment, by setting the q-axis voltage having the same magnitude as the d-axis voltage used in the rotor positioning step as the initial q-axis voltage V0, the motor 1 generated in the rotor positioning step of the motor 1 The drive torque and the drive torque at the start of the synchronous operation step are made the same, so that it is possible to smoothly shift from the rotor positioning step to the synchronous operation step.

  Further, according to the first embodiment, it is determined whether or not the motor 1 has reached the speed at which the axis error Δθ can be calculated, and if the motor 1 has reached the speed at which the axis error Δθ can be calculated, Since the mode shifts from the synchronous operation step to the normal operation, the mode shift failure due to insufficient acceleration of the motor 1 can be prevented.

(Modification of First Embodiment)
In the first embodiment described above, the estimated current speed of the motor 1 is a speed at which the d-axis current Id becomes zero. However, the present invention is not limited to this, and the estimated current speed of the motor 1 may be a speed at which the d-axis current Id is equal to or less than a predetermined value.

  The first embodiment has been described above.

[Embodiment 2]
In the first embodiment, the load applied to the motor 1 when the motor 1 is started is assumed to be about three times as large as that during the normal operation of the motor 1. The load of the motor 1 is a small compressor. On the other hand, when the startup control of the first embodiment is executed with a large compressor as a load, a load larger than a load assumed by a small compressor may be applied. In the second embodiment, it is assumed that the load applied to the motor 1 when the motor 1 is started is about six times as large as that in the normal operation of the motor 1 of the first embodiment.

  As described in the first embodiment, it is preferable that the current vectors (the d-axis current Id and the q-axis current Iq) be in the first quadrant of the current vector coordinates immediately after the motor 1 is started. By setting the d-axis voltage Vd to 0, the current vector can be kept in the first quadrant of the current vector coordinates. On the other hand, when the load torque is large, a starting torque larger than the load torque is necessary to increase the rotation speed of the motor 1, but if the starting torque is insufficient, the rotation speed does not increase. If the number of revolutions does not increase, the motor cannot consume the given power, and the surplus power increases. When the surplus power increases, the d-axis current largely flows in the positive direction. In the second embodiment, similarly to the first embodiment, control is performed such that the rotor speed estimated value estimated from the d-axis current reaches the speed command value. The estimated speed ωe (hereinafter, sometimes referred to as “speed estimated value”) increases. When the speed estimation value becomes larger than the speed command value, the q-axis voltage acts in the direction of decreasing from the above equation (12). As a result, the starting torque cannot be increased, the number of revolutions does not increase, the surplus power increases, and a vicious cycle occurs in which the d-axis current flows largely in the positive direction. That is, if the current vector is placed in the first quadrant when the load torque is large at the time of starting, the starting torque is controlled to decrease. Further, in a state where a sufficient driving torque cannot be secured, it may be difficult to smoothly perform a mode transition from the synchronous operation step to the normal operation. For example, in the first embodiment, when a load five times the normal load is applied to the motor 1, in the first embodiment, it may be difficult to smoothly perform the mode transition from the synchronous operation step to the normal operation. is there.

  Therefore, in the first embodiment, the d-axis voltage Vd is fixed to 0, whereas in the second embodiment, the d-axis voltage Vd is set to a negative voltage so that a sufficient starting torque can be applied to the load torque. And In the present embodiment, this voltage is described as a variable voltage, but is not limited thereto and may be a predetermined fixed voltage.

(Configuration of Motor Control Device in Synchronous Operation Step According to Second Embodiment)
In the second embodiment, a speed command type configuration corresponding to a large load torque shown in FIG. 9 is used instead of the configuration of the motor control device in the synchronous operation step according to the basic mode of FIG. FIG. 9 is a diagram illustrating an example of a configuration of a motor control device in a synchronous operation step according to the second embodiment.

  The motor control device 100B in the synchronous operation step according to the second embodiment has a microcomputer 10B instead of the microcomputer 10X in the basic mode. The microcomputer 10B has a controller 2B in place of the controller 2X in the basic mode, has a d-axis voltage generator 16B in place of the d-axis voltage generator 16X in the basic mode, and has a q-axis in the basic mode. It has a q-axis voltage generator 17B in place of the voltage generator 17X, and has a speed estimator 29B in place of the speed estimator 29X in the basic mode. The configuration of the motor control device 100B in the synchronous operation step according to the second embodiment is the same as the motor control device 100X according to the basic mode except for the controller 2B, the d-axis voltage generator 16B, the q-axis voltage generator 17B, and the speed estimator 29B. Is the same as

  The controller 2B controls the switch SW1 including the contacts CO0 to CO1 and the entire microcomputer 10B, and also controls, for example, a mode transition of the motor 1 from the synchronous operation step to the normal operation.

The d-axis voltage generator 16B calculates the d-axis voltage command value Vd ^* in the synchronous operation step from the q-axis current Iq output from the 3φ / dq converter 25 and the estimated electric angle ωe output from the speed estimator 29B. Generated and output to the dq / 3φ converter 21.

Here, the d-axis voltage Vd generated by the d-axis voltage generator 16B will be described. Hereinafter, the d-axis voltage command value Vd ^* is replaced with the d-axis voltage Vd.

  The d-axis voltage Vd generated by the d-axis voltage generator 16B is given by the above equation (1) from the dq-axis motor model equation in normal operation.

  The third term on the right-hand side of the above equation (1) can be regarded as 0 in the steady state, so that in the steady state, the above equation (1) becomes the above equation (2).

  When starting when a large load torque is being generated, the estimated speed value increases when the d-axis current increases in the positive direction. When the speed estimation value becomes larger than the speed command value, the q-axis voltage acts in the direction of decreasing from the above equation (12). As a result, the starting torque cannot be increased, the number of revolutions does not increase, the surplus power increases, and the d-axis current largely flows in the positive direction.

  On the other hand, from the above equation (2), if the d-axis voltage is controlled so that the d-axis current becomes 0, the d-axis current is reduced even when the motor 1 is started when a large load torque is generated. The increase in the forward direction is suppressed, and the estimated speed value does not increase excessively. If the speed estimation value does not increase with respect to the speed command value, the q-axis voltage does not work in a decreasing direction, and a q-axis current for normally applying a necessary starting torque can flow.

From the above equation (2), the d-axis voltage Vd when the d-axis current becomes 0 is expressed by the following equation (13).

  On the other hand, unlike Vd = 0 in the first embodiment, interference is generated between the d-axis and the q-axis by controlling the d-axis voltage as in the above equation (13). For this reason, each of the d-axis and q-axis voltage generators preferably has a non-interference term for canceling the influence of interference.

  As for the d-axis voltage, the right side of the above equation (13) becomes a non-interference term as it is, so that the influence of the interference on the q-axis side can be canceled. On the other hand, as for the q-axis voltage, the first term and the second term are non-interference terms as they are on the right side of the above equation (12), so that the influence of interference on the d-axis side can be canceled. From this, each of the d-axis and q-axis voltage generators can generate a non-interfering voltage command value.

The q-axis voltage generator 17B calculates the d-axis current Id output from the 3φ / dq converter 25, the estimated electric angle speed ωe output from the speed estimator 29B, the initial electric angle ωe0 of the motor 1, and q A q-axis voltage command value Vq ^* in the synchronous operation step is generated from the electric angular velocity command value ωe ^* generated inside the shaft voltage generator 17B and the initial q-axis voltage V0, and the generated q-axis voltage command value Vq ^*. Is output to the dq / 3φ converter 21. That is, the q-axis voltage generator 17B has the same configuration as the q-axis voltage generator 17A of the first embodiment.

  The q-axis voltage generator 17B generates a starting torque by setting the q-axis voltage having the same magnitude as the d-axis voltage at the time of positioning in the rotor positioning step as the initial q-axis voltage V0. The q-axis voltage generator 17B can shift the mode from the synchronous operation step to the normal operation by controlling the surplus power to a minimum while generating an appropriate q-axis voltage Vq for increasing the speed of the motor 1. At the same time, a speed sufficient to generate an induced voltage necessary for calculating the axis error Δθ in the normal operation is secured.

  The speed estimator 29B has a configuration similar to that of the speed estimator 29X according to the basic mode, but is based on the d-axis current Id output from the 3φ / dq converter 25 and is an electrical angle that is the current angular speed of the motor estimated. The estimated speed ωe is calculated and output to the q-axis voltage generator 17B and the position estimator 30X. The speed estimator 29B is an example of a speed estimating unit that estimates the current speed from the d-axis current in the dq coordinate system of the current detected by the detecting unit.

(D-axis voltage generator in synchronous operation step according to Embodiment 2)
FIG. 10 is a diagram illustrating an example of a configuration of a d-axis voltage generator in a synchronous operation step according to the second embodiment. The d-axis voltage generator 16B in the synchronous operation step according to the second embodiment includes a multiplier 16B-1 and a subtractor 16B-2.

The multiplier 16B-1 receives the estimated electric angle ωe, the q-axis current Iq, and the q-axis inductance Lq as inputs, and subtracts the result of multiplying the estimated electric angle ωe, the q-axis current Iq, and the q-axis inductance Lq by a subtractor 16B- Output to 2. The subtractor 16B-2 calculates a deviation (0−ωe · Lq · Iq) between 0 and the output of the multiplier 16B-1 to make the result of the multiplication by the multiplier 16B-1 negative. A d-axis voltage Vd is generated. Since the result of multiplying the output of the multiplier 16B-1 by -1 is the same as the result of subtracting the output of the multiplier 16B-1 from 0, the multiplier is replaced by a multiplier instead of the subtractor 16B-2. The output of 16B-1 may be multiplied by -1. The estimated electrical angle speed ωe is input to the multiplier 16B-1. However, when the estimated electrical angle speed ωe reaches the electrical angular speed command value ωe ^* and the speed is constant, the estimated electrical angle speed ωe is used instead of the estimated electrical angle speed ωe. the electrical angular velocity command value .omega.e ^* may be input to the multiplier 16B-1 to.

  As described above, the d-axis voltage Vd (d-axis drive voltage Vd) output from the d-axis voltage generator 16B in the second embodiment is represented by the above equation (13) instead of Vd = 0 in the first embodiment. The d-axis voltage generator 16B generates and outputs a d-axis voltage Vd according to the above equation (13). In the above equation (13), the right side corresponds to the calculation result by the subtractor 16B-2.

(Process of synchronous operation step according to Embodiment 2)
The process of the synchronous operation step according to the second embodiment is the same as the process of the synchronous operation step according to the first embodiment shown in FIG. Here, in the second embodiment, the convergence time for the actual rotation speed to converge to the optimum rotation speed is equal to the d-axis current which is the input of the q-axis voltage generator 17B and the speed estimator 29B, as in the first embodiment. It is obtained by solving the above equation (12) showing the relationship between Id and the output q-axis voltage Vq for the convergence time. The target arrival speed of the electric angular velocity command value ωe ^* and the estimated electric angular velocity ωe in the second embodiment is the same as in the first embodiment.

(Change of each value according to the second embodiment)
Hereinafter, with reference to FIG. 11A to FIG. 14B, regarding Embodiment 2 and Embodiment 1, when the motor load is large, the transition of the d-axis current and the q-axis current, the transition of the d-axis voltage and the q-axis voltage, The transition of the axis error Δθ, the transition of the estimated electrical angle speed and the transition of the speed command value will be described in comparison.

  11A to 14B, the section (1) that divides the time t on the horizontal axis indicates the section of the rotor positioning step, the section (2) indicates the section of the synchronous operation, and the section (2) is further divided. The section (2) ′ indicates the section of the acceleration region toward the target arrival speed, and the section (2) ″ indicates the section of the constant speed region after reaching the target arrival speed. The section of the acceleration region indicates the command speed. 11A is a section where the command speed is constant, and a section of (3) in FIGS. 11A, 12A, 13A, and 14A is a section of the normal operation. Show.

(Changes in d-axis voltage and q-axis voltage and changes in d-axis current and q-axis current in the second embodiment when the motor load is large (FIGS. 11A and 12A))
FIG. 11A is a diagram illustrating an example of changes in the d-axis current and the q-axis current according to the second embodiment when the load on the motor is large. FIG. 12A is a diagram illustrating an example of transition of the d-axis voltage and the q-axis voltage according to the second embodiment when the load on the motor is large.

  As shown in FIG. 12A, in the rotor positioning step (1), the q-axis voltage Vq is set to 0, and a constant d-axis voltage Vd is applied to the motor 1. Thereby, as shown in FIG. 11A, the d-axis current Id flows through the motor 1 in the rotor positioning step (1).

  Next, in the second embodiment, as shown in FIG. 12A, in the acceleration region of (2) ′, the d-axis voltage Vd calculated based on the above equation (13) and the d-axis voltage Vd calculated based on the above equation (12) The applied q-axis voltage Vq is applied to the motor 1. In the acceleration region (2) ′, the d-axis voltage Vd gradually decreases, while the q-axis voltage Vq increases more than the d-axis voltage Vd decreases. As a result, the q-axis current Iq increases in the positive direction.

Then, as shown in FIG. 12A, in the constant speed region of (2) ″ following the acceleration region of (2) ′, in the q-axis voltage Vq calculated based on the above expression (12), the above expression (12) is obtained. Converges to the optimal q-axis voltage by operating the integral terms of the second and third terms, that is, in the constant speed region of (2) ″, unlike the acceleration region of (2) ′, the q-axis voltage Although the voltage Vq is small, it starts to decrease. Further, the negative voltage of the d-axis voltage Vd also decreases. As the q-axis voltage Vq and the d-axis voltage start to decrease, both the q-axis current Iq and the d-axis current Id decrease as shown in FIG. 11A. Then, as shown in FIG. 11A, the speed command value ω ^* of the motor 1 reaches the target attainment speed, and a convergence time for converging to a q-axis voltage appropriate for the rotation speed has elapsed. At timing t1 when the electrical angle estimation speed ωe reaches the target arrival speed, the mode shift from the synchronous operation step of the motor 1 to the normal operation is performed.

(Changes in d-axis voltage and q-axis voltage and changes in d-axis current and q-axis current in Embodiment 1 when the motor load is large (FIGS. 11B and 12B))
FIG. 11B is a diagram illustrating an example of transition of the d-axis current and the q-axis current according to the first embodiment when the load of the motor is large. FIG. 12B is a diagram illustrating an example of changes in the d-axis voltage and the q-axis voltage according to the first embodiment when the load on the motor is large.

  As shown in FIG. 12B, in the rotor positioning step (1), the q-axis voltage Vq is set to 0, and a constant d-axis voltage Vd is applied to the motor 1. Thus, as shown in FIG. 11B, the d-axis current Id flows through the motor 1 in the rotor positioning step (1).

Next, in the first embodiment, as shown in FIG. 12B, in the acceleration region of (2) ′, the d-axis voltage Vd is set to 0, and the q-axis voltage Vq calculated based on the above equation (12) is set to the motor 1 Is applied to However, when the load of the motor is large, in the first embodiment, as shown in FIG. 12B, in the latter half of the acceleration region of (2) ′, the control of the q-axis voltage Vq becomes impossible, and the q-axis voltage Vq decreases. Would. This is because, as shown in FIG. 14B described later, it is difficult for the estimated electrical angle speed ωe to follow the electrical angle target speed ωe ^{* in} the latter half of the acceleration region of (2) ′, and the speed increases. This is because the q-axis voltage Vq decreases in an attempt to reduce the speed. Accordingly, as shown in FIG. 11B, in the latter half of the acceleration region of (2) ′, the control of the q-axis current Iq becomes impossible, the q-axis current Iq decreases, and the control of the d-axis current Id is performed. Also becomes impossible.

(Transition of axis error Δθ in Embodiment 2 and Embodiment 1 when motor load is large (FIGS. 13A and 13B))
FIG. 13A is a diagram illustrating an example of a change in the axis error Δθ according to the second embodiment when the motor load is large. FIG. 13B is a diagram illustrating an example of a change in the axis error Δθ according to the first embodiment when the motor load is large.

  As shown in FIG. 13A, in the second embodiment, the axis error Δθ converges to around 0 in the first half of the acceleration region of (2) ′.

  On the other hand, in the first embodiment, as shown in FIG. 13B, in both the acceleration region of (2) ′ and the constant speed region of (2) ″, the axis error Δθ does not converge to around 0 and is large. 13B, the axis error Δθ diverges in the latter half of the acceleration region (2) ′ where the control of the q-axis current Iq and the d-axis current Id becomes impossible (FIG. 11B).

(Changes in estimated electric angle speed and target electric angle speed in the second and first embodiments when the motor load is large)
FIG. 14A is a diagram illustrating an example of transitions of the estimated electric angle speed and the target electric angle speed according to the second embodiment when the motor load is large. FIG. 14B is a diagram illustrating an example of changes in the estimated electric angle speed and the target electric angle speed according to the first embodiment when the load on the motor is large.

As shown in FIG. 14A, in the second embodiment, in both the acceleration region (2) ′ and the constant speed region (2) ″, the estimated electric angle ωe is equal to the electric angular speed command value (that is, the electric angle target). (Speed) ωe ^* to accelerate.

On the other hand, in the first embodiment, as shown in FIG. 14B, the estimated electric angular velocity ωe follows the electric angular velocity command value ωe ^* (that is, the electric angular target velocity) in the latter half of the acceleration region of (2) ′. It becomes difficult to perform the control and control becomes impossible, and the value becomes 0 in the constant speed region of (2) ″.

(Relationship between dq-axis current vector and γδ-axis current vector)
FIG. 15 is a diagram illustrating an example of an ideal relationship between a current vector on the dq axis and a current vector on the γδ axis. FIG. 16 is a diagram illustrating an example of the relationship between the dq-axis current vector and the γδ-axis current vector according to the first embodiment. FIG. 17 is a diagram illustrating an example of a relationship between a dq-axis current vector and a γδ-axis current vector according to the second embodiment.

As shown in FIG. 15, when the direction of the dq-axis current vector I _dq 0 is on the q-axis, the rotational force is applied to the rotor most. Moreover, equal status and direction of the direction of current vector I _{dq 0} of the current vector I _{the ??} 0 of the ?? axes, since the axis error Δθ is in a state to be 0, it is an ideal state.

In contrast, in the case of the first embodiment, as shown in FIG. 16, that the axis error Δθ1 is caused by the load of the motor 1, the direction of the current vector I _{the ??} 0 is the direction of the current vector I _{dq 0} It advances too much by Δθ1. On the other hand, in the first embodiment, the d-axis voltage is set to 0, and the q-axis voltage Vq ^* is controlled according to the above equation (12). Thus, in the embodiment 1, as the current vector I _{the ??} 1 shown in FIG. 16, it is possible to return the direction of the current vector I _{the ??} 0 where direction is too advanced by the minute position error .DELTA..theta.1, current vector I _{the ??} 1 can be kept in the first quadrant of the dq coordinates. However, in the first embodiment, the direction of the current vector on the γδ axis can be changed, but the magnitude does not change. When the γ-axis is set to 0 degree and the δ-axis is set to 90 degrees, in the first embodiment, the control range of the current vector of the γδ axis ranges from 90 degrees to 45 degrees according to the above equation (12).

On the other hand, in the case of the second embodiment, since the d-axis voltage Vd is calculated according to the above equation (13), the magnitude of the γδ-axis current vector, such as the current vector I _γδ 2A shown in FIG. _γδ 0 can be increased. Therefore, in the second embodiment, even when the load of the motor 1 is large, the axis error can be made smaller than in the first embodiment (Δθ2 <Δθ1). Further, in the second embodiment, similarly to the first embodiment, the q-axis voltage Vq ^* is controlled according to the above equation (12). For this reason, in the second embodiment, the direction of the current vector _Iγδ2A whose direction is excessively advanced can be returned by the amount of the axis error Δθ2 like the current vector _Iγδ2B shown in FIG. Similarly, the current vector I _γδ 2B can be kept in the first quadrant of the dq coordinates. However, in the second embodiment, since the d-axis voltage Vd is calculated according to the above equation (13), when the γ-axis is set to 0 degree and the δ-axis is set to 90 degrees, the control width of the current vector of the γδ axis is from 90 degrees. The range is 80 degrees, which is smaller than in the first embodiment. However, in the second embodiment, the d-axis voltage Vd is calculated according to the above equation (13), so that the axis error becomes smaller than in the first embodiment. Therefore, the control width of the γδ-axis current vector is smaller than that in the first embodiment. The control width is sufficient.

  As described above, in the second embodiment, the d-axis voltage generator 16B outputs a negative voltage as the d-axis voltage. The d-axis voltage generator 16B outputs, for example, the d-axis voltage calculated according to the above equation (13). Therefore, in the second embodiment, even when the load of the motor 1 is larger than that of the first embodiment, it is possible to control the q-axis voltage equivalent to that of the first embodiment while obtaining a necessary torque.

  The second embodiment has been described above.

  The information including the specific names, processes, controls, and various types of data and parameters in the above-described embodiment and illustrations are merely examples, and can be appropriately changed unless otherwise specified. In addition, the configuration of each unit or each device in the above-described embodiment may be appropriately dispersed or integrated based on processing load, mounting efficiency, and the like. In addition, each processing in the above-described embodiment may be executed by appropriately changing the processing order from the processing load and the mounting efficiency.

  The broader aspects of the above-described embodiments are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the general inventive concept or scope as defined by the appended claims and equivalents thereof.

2X, 2A, 2B Controller 10X, 10A, 10B Microcomputer 11 Subtractor 12 Speed controller 13 Excitation current controller 14 Subtractor 15 Subtractor 16 d-axis current controller 16X d-axis voltage generator 17 q-axis current controller 17X, 17A q-axis voltage generator 17A-1 Ld multiplier 17A-2 subtractor 17A-3 integrator 17A-4 subtractor 17A-5 Ψmultiplier 17A-6 adder 17A-7 adder 17A-8 electric angular velocity Command generator 18 Decoupling controller 19 Subtractor 20 Adder 21 dq / 3φ converter 22 PWM generator 23 IPM
24 3φ current calculator 25 3φ / dq converter 26 Axis error calculation processor 29 PLL controllers 29X, 29A, 29B Speed estimator 29X-1 Proportional term calculation processor 29X-2 Integral term calculation processor 29X-3 Adder 30, 30X Position estimator 31 1 / Pn processor 100X, 100A, 100B Motor controller CO0, CO1, CO2 Contact SW1 switch

Claims (6)

A drive unit that drives a motor by supplying a drive voltage generated based on a difference between a target speed of the motor and a current speed of the motor to the motor,
A detection unit that detects a current flowing through the motor,
A speed estimating unit that estimates the current speed from a d-axis current in a dq coordinate system of the current detected by the detecting unit;
a d-axis voltage generator that generates a d-axis drive voltage as the d-axis drive voltage in a dq coordinate system;
a q-axis voltage generation unit that generates a q-axis drive voltage as the q-axis drive voltage in the dq coordinate system;
A drive voltage generation unit that generates the drive voltage from the d-axis drive voltage and the q-axis drive voltage,
When starting the motor,
The d-axis voltage generation unit outputs a negative voltage as the d-axis drive voltage,
The q-axis voltage generation unit outputs an initial drive voltage, and thereafter, at least, generates the q-axis drive voltage from the initial drive voltage, the target speed, and the current speed,
Motor control device. The d-axis voltage generation unit generates -ωe · Lq · Iq (where “ωe” is the current speed, “Lq” is the q-axis inductance of the motor, and “Iq” is the q-axis current ),
The motor control device according to claim 1. The current speed is a speed at which the d-axis current becomes 0,
The motor control device according to claim 1. The q-axis voltage generation unit generates the q-axis drive voltage from the following equation (1):
The motor control device according to claim 2.

In the above equation (1), “Vq ^* ” is the q-axis drive voltage, “ωe ^* ” is the target speed, “ωe0” is the initial electric angular speed of the motor, and “Ld” is the d-axis of the motor. Inductance, “Id” is the d-axis current, “R” is the winding resistance of the motor, “J” is the inertia of the motor, “Ψ” is the flux linkage of the motor, and “Kc” is the integral gain adjustment coefficient. , “Ωe” is the current speed, “V0” is the initial drive voltage, and the integral section on the right side of the above equation (1) is the time from the start of synchronous operation of the motor to the present. The initial drive voltage has the same voltage value as the voltage applied to the d-axis in the dq coordinate system for positioning the rotor during the initial drive.
The motor control device according to claim 1. After the target speed reaches the target arrival speed at which the axis error of the motor can be calculated, after a lapse of a predetermined time, the mode shifts to the position feedback operation mode of the motor for calculating the axis error of the motor.
The motor control device according to claim 1.

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