JP7206707B2 - motor controller - Google Patents

Description

The disclosed technology relates to a motor control device.

In general, 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 so 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. Furthermore, the motor control device converts the d-axis voltage command value and the q-axis voltage command value into three-phase voltage command values, and a PWM (Pulse Width Modulation) generator generates PWM based on the three-phase voltage command values. A signal is generated and output to an IPM (Intelligent Power Module). The IPM applies three-phase voltages (U-phase voltage Vu, V-phase voltage Vv, and W-phase voltage Vw) to the motor to drive and control the motor by performing switching control according to the input PWM signal.

Further, when starting the motor, the motor control device operates the stopped motor in a range from zero speed to extremely low speed. Since the induced voltage is extremely small at extremely low rotation speeds, it is difficult to accurately detect the rotor position. Therefore, the motor control device increases the induced voltage and performs control to increase the rotation speed of the motor so that the position of the rotor can be detected accurately. When starting a motor, the control to increase the rotation speed of the motor while synchronizing the rotating magnetic field generated by the stator of the motor with the rotor is called "synchronous operation". The motor control device shifts the mode to "normal operation" after performing the synchronous operation of the motor.

However, since the motor control device does not detect the rotor position during synchronous operation, control may become difficult depending on the state of the load on the motor. Therefore, various techniques have been proposed to perform start control according to the state of the load on the motor.

For example, there is a technique of increasing the rotation speed of the motor when the load is small during the synchronous operation of the motor, and consuming the surplus electric power of the drive voltage of the motor by the increase in the rotation speed.

JP 2013-207868 A

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

The disclosed technique has been made in view of the above, and aims to apply an appropriate voltage to the motor when starting the motor.

In an aspect of the disclosure, a motor control device includes a drive section, a detection section, a speed estimation section, a d-axis voltage generation section, a q-axis voltage generation section, and a drive voltage generation section. The driving unit drives the motor by supplying a driving voltage generated based on a difference between a target speed of the motor and a current speed of the motor. The detector detects a current flowing through the motor. The speed estimator estimates the current speed from the d-axis current in the dq coordinate system of the current detected by the detector. The d-axis voltage generator generates a d-axis drive voltage as the drive voltage for the d-axis in the dq coordinate system. The q-axis voltage generator generates a q-axis drive voltage as the drive voltage for the q-axis in the dq coordinate system. The drive voltage generator generates the drive voltage from the d-axis drive voltage and the q-axis drive voltage. Then, when the motor is started, the d-axis voltage generator outputs a negative voltage as the d-axis drive voltage, the q-axis voltage generator outputs an initial drive voltage, and then at least: The q-axis drive voltage is generated from the initial drive voltage, the target speed and the current speed.

According to the disclosed aspect, an appropriate voltage can be applied to the motor when starting the motor. 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 showing an example of the configuration of a motor control device during normal operation according to the basic configuration. FIG. 2A is a schematic diagram showing an example of a rotor positioning step according to the basic form. FIG. 2B is a schematic diagram showing an example of a rotor positioning step according to the basic form. FIG. 3 is a diagram showing an example of the configuration of the motor control device in the synchronous operation step according to the basic form. FIG. 4 is a vector diagram showing a motor model formula in a steady state. FIG. 5 is a diagram showing an example of a configuration of a speed estimator (electrical angle) according to the basic form. FIG. 6 is a diagram showing an example of the configuration of the motor control device in the synchronous operation step according to the first embodiment. FIG. 7 is a diagram showing an example of the configuration of the q-axis voltage generator in the synchronous operation step according to the first embodiment. FIG. 8 is a diagram showing a flowchart showing an example of processing of a synchronous operation step according to the first embodiment. FIG. 9 is a diagram showing an example of the configuration of the motor control device in the synchronous operation step according to the second embodiment. FIG. 10 is a diagram showing an example of the configuration of the d-axis voltage generator in the synchronous operation step according to the second embodiment. FIG. 11A is a diagram showing an example of changes in d-axis current and q-axis current according to the second embodiment when the load on the motor is large. FIG. 11B is a diagram showing an example of changes in the d-axis current and the q-axis current according to the first embodiment when the load on the motor is large. FIG. 12A is a diagram showing an example of changes in the d-axis voltage and the q-axis voltage according to the second embodiment when the load on the motor is large. 12B is a diagram showing an example of changes in the d-axis voltage and the q-axis voltage according to Embodiment 1 when the motor load is large; FIG. FIG. 13A is a diagram showing an example of transition of an axis error according to the second embodiment when the load on the motor is large. 13B is a diagram showing an example of transition of the axis error according to the first embodiment when the load on the motor is large; FIG. FIG. 14A is a diagram showing an example of changes in the estimated electrical angle speed and the target electrical angle speed according to the second embodiment when the load on the motor is large. 14B is a diagram showing an example of changes in the estimated electrical angle speed and the target electrical angle speed according to the first embodiment when the load on the motor is large; FIG. FIG. 15 is a diagram showing an example of an ideal relationship between the dq-axis current vector and the γδ-axis current vector. FIG. 16 is a diagram showing 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 showing an example of the relationship between the dq-axis current vector and the γδ-axis current vector according to the second embodiment.

A basic form, embodiments, and modifications of the motor control device according to the technology disclosed in the present application will be described below in detail with reference to the drawings. Note that the disclosed technology is not limited by the following basic modes, embodiments, and modified examples. The motor control device shown in the following basic form, embodiments, and modifications will be described as a control device for a motor whose load is a propeller fan, refrigerant, or the like used in an air conditioner or the like. can be applied to the control of The following basic forms, embodiments, and modified examples can be appropriately combined and implemented within a consistent range.

Also, in the following basic modes, embodiments, and modifications, the configuration and processing according to the disclosed technology will be mainly described, and descriptions of other configurations and processing will be simplified or omitted as appropriate. In addition, in the following basic mode, embodiment, and modification, the same reference numerals are given to the same configurations and processes, and descriptions of the already-outed configurations and processes are omitted.

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

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

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

Also, the microcomputer 10X includes a controller 2X, a subtractor 11, a speed controller 12, an excitation current controller 13, a subtractor 14, a subtractor 15, a d-axis current controller 16, a q-axis current controller 17, a non-interfering conversion controller 18, subtractor 19, adder 20, dq/3φ converter 21, PWM (Pulse Width Modulation) generator 22, 3φ/dq converter 25, axis error 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 of the motor 1 (mechanical angle 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 ^* that makes the speed deviation Δω output by the subtractor 11 smaller, and outputs it to the exciting current controller 13 and the subtractor 15 . The excitation 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 it to the subtractor 14 . Also, the d-axis and the q-axis represent the coordinate axes of a two-phase rotating coordinate system (current vector coordinates), and Id, Iq, and Vd and Vq, which will be described later, represent current and voltage on these coordinate axes. The two-phase rotating coordinate system is also called a dq coordinate system.

A 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 . A 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 .

A 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 . A q-axis current controller 17 generates a q-axis voltage command value Vq ^** from the q-axis current deviation ΔIq output by the subtractor 15 .

A non-interfering controller 18 cancels the interference of the d-axis and the q-axis and generates a non-interfering correction value for controlling each independently. Specifically, the decoupling controller 18 calculates the d-axis voltage command value Vd ^* from the d-axis current Id output by the 3φ/dq converter 25 and the estimated electrical angle speed ωe output by the PLL controller 29. A d-axis decoupling correction value Vda for decoupling ^* is generated and output to the subtractor 19 . In addition, the decoupling controller 18 converts the q-axis voltage command value Vq ^** into a A q-axis non-interfering correction value Vqa for interfering is generated and output to the adder 20 .

A 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 ^* is generated by decoupling the command value Vd ^** , and is 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 obtain the q-axis voltage A q-axis voltage command value Vq ^* is generated by decoupling the command value Vq ^** , and is 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 by the position estimator 30, to generate the non-interfering two-phase d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* are 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 ^* , which are three-phase voltage command values. 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 . A U-phase output voltage command value Vu ^* , a V-phase output voltage command value Vv ^* , a 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 three-phase fixed values. Voltage and current in the coordinate system.

The PWM generator 22 generates 6-phase PWM signals 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 supplies them to the IPM 23. Output. 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 used as the voltage command values, and the dq/3φ converter 21 may be included in the signal generator.

Based on the 6-phase PWM signal output from the PWM generator 22, the IPM 23 generates AC voltages to be applied to the U-phase, V-phase, and W-phase of the motor 1 from the externally supplied DC voltage Vdc. Then, the AC voltages are applied to the U-phase, V-phase, and W-phase of the motor 1, respectively. The IPM 23 is an example of a drive unit that supplies a drive voltage generated based on the difference between the target speed and the current speed of the motor to the motor to drive the motor. The IPM 23 may be an IC (Integral Circuit) in which transistors and diodes are integrated, for example, but may also be configured by arranging each component on a circuit board, for example.

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

When the contact CO0 of the switch SW1 is connected to the contact CO1, the 3φ current calculator 24 uses the 1-shunt current detection method to obtain the 6-phase PWM switching information output from the PWM generator 22 and the shunt resistance (Fig. (not shown) is used to detect the bus current, and the U-phase current Iu, V-phase current Iv, and 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 connected to the contact CO2, the 3φ current calculator 24 uses the 2CT current detection method to , two CTs (Current Transformers) detect two-phase currents, and the remaining phase currents are calculated from the relational expression Iu+Iv+Iw=0 of Kirchhoff's law.

For current detection, only one of the 1-shunt current detection method, the 2CT current detection method, and the like may be used. In that case, the detection circuit and the switch SW1 for the current detection method other than the used current detection method can be omitted. The 3φ current calculator 24 is an example of a detector that detects the current flowing through the motor.

The 3φ/dq converter 25 uses the electrical angle phase θe output from the position estimator 30 to convert the three-phase U-phase current Iu, V-phase current Iv, and W-phase current Iw output from the 3φ current calculator 24 . is converted into two-phase d-axis current Id and q-axis current Iq. Then, the 3φ/dq converter 25 transfers the d-axis current Id to the subtractor 14, the non-interfering controller 18, and the axis error arithmetic processor 26, and the q-axis current Iq to the subtractor 15, the non-interfering controller 18, They are output to the axis error arithmetic processor 26 respectively.

The axis error processor 26 calculates the d-axis voltage command value Vd ^* output by the subtractor 19, the q-axis voltage command value Vq ^* output by the adder 20, and the d 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 the deviation between the actual dq-axis and the control dq-axis (γδ-axis).

The PLL controller 29 calculates an estimated electrical angle speed ωe, which is the estimated current angular speed of the rotation of the motor 1, from the axis error Δθ output by the axis error processor 26, and the non-interfering controller 18, They are 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 electrical angle estimated speed ωe output from the PLL controller 29 . The position estimator 30 then outputs the electrical angle phase θe to the dq/3φ converter 21 and the 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 pole logarithm Pn of the motor 1 to calculate the current rotation speed ω of the motor 1 and outputs it to the subtractor 11 . .

(Motor startup control according to basic form)
Since a sufficient induced voltage is generated in the motor 1 during normal operation of the motor 1, the motor control device 100X drives the motor 1 by position feedback control for calculating the axis error. However, when the motor 1 is started, the rotation speed is extremely low, and a sufficient induced voltage is not generated. The device 100X cannot start the motor 1 using the normal operation control scheme.

Therefore, the motor control device 100X starts the motor 1 by starting control different from normal operation. In the start-up control of the motor 1, the motor control device 100X firstly executes a rotor positioning step for aligning the initial rotor position, and secondly, performs a synchronous operation to accelerate the motor 1 until the position can be detected. Steps are executed, and then the mode shifts to normal operation in which the motor 1 is driven by position sensorless vector control.

(Rotor positioning according to basic configuration)
2A and 2B are schematic diagrams showing an example of a rotor positioning step according to the basic form. As shown in FIGS. 2A and 2B, rotor positioning is performed by applying a voltage (current) in the d-axis direction of the dq-axis coordinate system to obtain the control-side rotor position (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 a predetermined position (position on the control side), a torque larger than the load torque under the operating environment is generated. Driving torque can be generated by using the voltage at this time as the initial q-voltage V0 (q-axis voltage) of the synchronous operation step.

(Configuration of motor control device in synchronous operation step according to basic configuration)
FIG. 3 is a diagram showing an example of the configuration of the motor control device in the synchronous operation step according to the basic form. 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 ^* . A mode in which the motor is driven and controlled.

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

The microcomputer 10X also 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, a switch SW1 including contacts CO0 to CO1, a 3φ current calculator 24, It has a 3φ/dq converter 25, a speed estimator 29X, and a position estimator 30X. The microcomputer 10X also 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 microcomputer 10X as a whole, and also controls mode transition of the motor 1 from the synchronous operation step to normal operation, for example.

Note that FIG. 3 shows only the configuration in the synchronous operation step of the motor, with respect to the components of the microcomputer included in the motor control device according to the basic embodiment.

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 position of the rotor output by the position estimator 30X, to obtain the d-axis voltage command value Vd ^* and the q-axis voltage 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 sent to the PWM generator 22. Output.

The PWM generator 22, IPM 23, and 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 obtain the three-phase U-phase current Iu, V-phase current Iv, and W-phase current Iw output from the 3φ current calculator 24. is converted into two-phase d-axis current Id and 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 an electrical angle estimated speed ωe, which is the estimated 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 estimated speed ωe 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 applies the dq/3φ converter 21 and the 3φ/dq conversion output to the device 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. In the following, the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* are replaced with the d-axis voltage Vd ^* and the q-axis voltage Vq ^* , respectively.

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 formula (1) from the dq-axis motor model formula during 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 electrical angle speed of the motor 1, and "Lq" is the motor 1 is the q-axis inductance of the motor 1, "Iq" is the q-axis current of the motor 1, "ρ" is the 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 a steady state, the above equation (1) becomes the following equation (2) in a steady state.

It should be noted that the d-axis voltage Vd represented by the above equation (2) is as shown in the vector diagram of FIG. FIG. 4 is a vector diagram showing a motor model formula 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 the interlinkage magnetic flux of the motor 1.

From the above equation (2), it can be seen that the d-axis voltage Vd is 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 starting the motor 1 flows in the positive direction. This is because the initial q-axis voltage V0 in the synchronous operation step generates drive torque, and the d-axis voltage Vd ^* immediately after starting the motor 1 is not the optimum voltage. The optimum voltage is a voltage that creates an optimum state, and the optimum state means a state with little surplus power. Immediately after the transition to the synchronous operation step, the voltage is instantaneously excessive. Therefore, the d-axis voltage Vd ^* immediately after the start of the motor 1 is generated in the positive direction of the d-axis side by using the surplus power other than the power required for rotating the motor 1 as a reactive 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 vector (d-axis current Id and 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, there is a high degree of margin with respect to changes in the load on the motor 1 and increases in the rotation speed. Therefore, the d-axis current Id generated in the positive direction on the d-axis side immediately after the motor 1 is started is used to control the d-axis current Id in the positive direction. In this case, the current vector (d-axis current Id and q-axis current Iq) has both the d-axis current Id and the q-axis current Iq in the positive direction, that is, in the first quadrant of the current vector coordinates.

Therefore, in the above equation (2), in order to make both the d-axis current Id and the q-axis current Iq positive, 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 is set in the above equation (2) and the equation is transformed into 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 according to the above equation (3). It 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 during positioning in the rotor positioning step as the initial q-axis voltage V0. The surplus electric power generated at this time is consumed as the electric power necessary for rotating the load connected to the motor 1 as the rotational speed of the motor 1 increases, so the surplus electric power gradually becomes zero. The d-axis current Id gradually moves 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, which will be described later. That is, the q-axis drive voltage Vq ^* output by the q-axis voltage generator 17X generates surplus power. As the number of revolutions of the motor 1 increases, the reactive component (surplus power) disappears, so the d-axis current Id moves from the positive direction to the negative direction. That is, as the rotation speed ω of the motor 1 increases, the d-axis current Id changes from the positive direction to the negative direction, and the d-axis current Id becomes zero. In other words, the electrical angle estimated speed ωe as the current speed of the motor 1 estimated by the speed estimator 29X is the speed at which the d-axis current Id is zero.

(Configuration of speed estimator (electrical angle) according to basic configuration)
FIG. 5 is a diagram showing an example of a configuration of a speed estimator (electrical angle) according to the basic form. The speed estimator 29X includes a proportional term calculation processor 29X-1 and an integral term calculation processor 29X-2 connected in parallel to the input of the d-axis current Id, a proportional term calculation processor 29X-1 and an integral term calculation processor. It has an adder 29X-3 for adding the processing results of the unit 29X-2. The speed estimator 29X utilizes the characteristic that as the speed of the motor 1 increases, the axis error Δθ decreases and the surplus electric power is converted into torque so that the d-axis current Id becomes 0. Speed estimation is performed by processing with integral proportional control (PI control). When the d-axis current Id becomes 0, the estimated electrical angle speed ωe of the motor 1 at the given q-axis voltage Vq is obtained.

Specifically, the speed estimator 29X calculates the estimated electrical angle speed 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. Note that the integration interval 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 time.

However, in the motor control device 100X in the synchronous operation step according to the basic configuration shown in FIG. Although the margin for the load of the motor 1 is ensured, the rotational speed ω of the motor 1 varies depending on the load. Therefore, even if the mode transition from the synchronous operation step to the normal operation is performed normally, the rotation speed ω of the motor 1 may not be sufficient 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 for calculating 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 embodiment 1)
Therefore, in Embodiment 1, instead of the configuration of the motor control device in the synchronous operation step according to the basic configuration of FIG. 3, the configuration of the speed command type shown in FIG. FIG. 6 is a diagram showing an example of the configuration of the motor control device in the synchronous operation step according to the first embodiment.

A motor control device 100A in the synchronous operation step according to the first embodiment has a microcomputer 10A instead of the microcomputer 10X of the basic form. The microcomputer 10A has a controller 2A in place of the controller 2X in the basic form, a q-axis voltage generator 17A in place of the q-axis voltage generator 17X in the basic form, and speed estimation in the basic form. It has a speed estimator 29A instead 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 that of the motor control device 100X according to the basic form 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 microcomputer 10A as a whole, and controls mode transition of the motor 1 from the synchronous operation step to normal operation, for example.

The q-axis voltage generator 17A generates the d-axis current Id output by the 3φ/dq converter 25, the estimated electrical angle speed ωe output by the speed estimator 29A, the initial electrical angle speed ωe0 of the motor 1, 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 is output to the dq/3φ converter 21. do.

The q-axis voltage generator 17A, similarly to the q-axis voltage generator 17X of the basic form, sets the q-axis voltage having the same magnitude as the d-axis voltage during positioning in the rotor positioning step as the initial q-axis voltage V0. , to generate the drive torque. The surplus electric power generated at this time is used as the electric power necessary for rotating the actual load connected to the motor 1 as the number of rotations of the motor 1 increases, so the reactive portion (surplus electric power) disappears.

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 It is possible to ensure a speed sufficient to generate the induced voltage required for the operation, and the mode transition from the synchronous operation step to the normal operation becomes possible.

The speed estimator 29A has the same configuration as the speed estimator 29X according to the basic form, but the electric angle An 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 estimator that estimates the current speed from the d-axis current in the dq coordinate system of the current detected by the detector.

Here, the q-axis voltage Vq generated by the q-axis voltage generator 17A will be described. In the following description, 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 formula (5) from the dq-axis motor model formula during 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, and "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 .

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

It should be noted that the q-axis voltage Vq represented by the above equation (6) is as shown in the vector diagram of FIG. In the above equation (6), the first term on the right side is term6-1 in FIG. 4, the second term on the right side is term6-2 in FIG. 4, and the third term on the right side is term6-3 in FIG.

From the initial q-axis voltage V0 immediately after the motor 1 is started after the rotor positioning step is completed, the electrical angular initial velocity ωe0 generated at the initial q-axis voltage V0, and the electrical angular velocity command value ωe ^* , the q-axis voltage Vq is obtained as follows: (7) It is represented by Formula.

Equation (7) includes a term including the q-axis current Iq. As in the basic mode, the speed estimator 29A calculates an estimated electrical angle speed ωe that makes the d-axis current Id zero. Further, when the speed of the motor 1 increases due to the q-axis voltage Vq, the reactive power, which is surplus power, disappears, and the d-axis current Id approaches 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. In order to control the rotor speed by controlling the q-axis voltage Vq while setting the d-axis current Id to 0, the q-axis voltage Vq to be applied to the motor 1 can be calculated from the command speed of the rotor. Convert the q-axis current Iq to velocity.

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

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

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

That is, the angular acceleration is represented by a velocity deviation, and the q-axis voltage necessary for the electrical angular velocity command value ωe ^* is generated by integrating the velocity deviation. From the above formulas (8) to (10), the q-axis current Iq is given by the following formula (11). Note that the integration interval 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 time.

By substituting the above equation (11) for “Iq” in the second term on the right side of the above equation (7) and arranging it, the q-axis voltage Vq can be obtained as shown in the following equation (12) by the q-axis current Iq is expressed without 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 showing an example of the 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, an addition 17A-6, an adder 17A-7, and an electrical angular velocity command generator 17A-8.

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

The Ld multiplier 17A-1 receives the d-axis current Id and the electrical angular velocity command value ωe ^* as inputs, 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 of the above equation (12) corresponds to the result of calculation by the Ld multiplier 17A-1.

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

The integrator 17A-3 outputs the result of integrating the input from the subtractor 17A-2 to the 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 electrical angular velocity command value ωe ^* and the electrical angular initial velocity ωe0 as inputs, and outputs the result of subtracting the electrical angular initial velocity ωe0 from the electrical 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 calculation by the subtractor 17A-4.

The Ψ multiplier 17A-5 multiplies the input from the subtractor 17A-4 by the flux linkage Ψ of the motor 1 and outputs the result to the adder 17A-6. The first term on the right side of the above equation (12) corresponds to the calculation 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 calculation 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 addition result of the two inputs as the q-axis voltage Vq. The addition of the fourth term on the right side in the above equation (12) corresponds to the calculation by the adder 17A-7.

(Processing of Synchronous Operation Step According to Embodiment 1)
FIG. 8 is a diagram showing a flowchart showing an example of processing 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 motor 1 starts to start.

The q-axis voltage generator 17A generates a q-axis voltage (q-axis drive voltage) Vq ^* using the deviation between the electrical angular velocity command value ωe ^* generated by the electrical angular velocity command generator 17A-8 and the estimated electrical angular velocity ωe. Generate. Therefore, in the synchronous operation step, the estimated electrical angle speed ωe serves as feedback control, forming 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. In other words, even if the rotation speed reaches the target speed at which the synchronous operation can be shifted to the normal operation, the q-axis voltage may still have surplus electric power. In that case, by providing a convergence time for converging the q-axis voltage to an appropriate one for the rotational speed, it is possible to seamlessly shift to normal operation with less shock at the time of switching.

Here, the convergence time is obtained from the input/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, which is the input of the q-axis voltage generator 17A and the speed estimator 29A, and the q-axis voltage Vq, which is the output, for the convergence time. Ask for it. Therefore, the convergence time can be obtained from the constants given in the above equation (12) by calculation with a small amount of computation.

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 electrical angular velocity command value ωe ^* generated by the electrical angular velocity command generator 17A-8, It is determined whether or not the electrical angular velocity command value ωe ^* has reached a predetermined target reaching velocity. If step S11: Yes, that is, if the electrical angular velocity command value ωe ^* reaches a predetermined target reaching velocity, the controller 2A shifts the process to step S12. On the other hand, if step S11: No, that is, if the electrical angular velocity command value ωe ^* has not reached the predetermined target arrival velocity, the controller 2A shifts the process to step S15.

At step S12, the controller 2A determines whether or not the above convergence time has elapsed. If step S12: Yes, that is, if the convergence time has elapsed, the controller 2A moves the process to step S13. On the other hand, if step S12: No, that is, if the convergence time has not elapsed, the controller 2A shifts the process to step S16.

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 .DELTA..theta. can be calculated. If step S13: Yes, that is, if the estimated electrical angle speed ωe reaches the target arrival speed, the controller 2A shifts the process to step S14. On the other hand, if step S13: No, that is, if the estimated electrical angle speed ωe has not reached the target speed, the controller 2A shifts the process to step S17.

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

In step S15, the controller 2A controls the q-axis voltage generator 17A to start or continue the process of generating the q-axis voltage (q-axis drive voltage) Vq ^* . After completing the process of step S15, the controller 2A shifts the process to step S11. Also, in step S16, the controller 2A controls the q-axis voltage generator 17A to continue the process of generating the q-axis voltage (q-axis drive voltage) Vq ^* . After completing the process of step S16, the controller 2A shifts the process to step S12.

In step S17, the electrical angular velocity command value ωe ^* has reached the target velocity and the estimated electrical angle velocity ωe has not yet reached the target velocity even after the elapsed convergence time. Executes error processing (for example, motor start/stop, motor start re-execution, error notification, etc.) when an error that cannot be performed occurs. When step S17 ends, the controller 2A ends the processing of the synchronous operation step according to the first embodiment.

According to the first embodiment described above, the q-axis voltage (q-axis drive voltage) Vq ^* is controlled according to the difference between the electrical angular velocity command value ωe ^* and the estimated electrical angular velocity ωe. Therefore, the q-axis voltage (q-axis driving voltage) Vq ^* corresponding 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 excessive voltage (overcurrent).

Further, according to the first embodiment, by fixing the d-axis voltage to 0 and controlling only the q-axis voltage, it is possible to easily control the speed of the motor 1 and suppress surplus power. 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 load fluctuations of the motor 1 and acceleration fluctuations of the motor 1 .

Further, according to the first embodiment, the estimated electrical angle speed ωe sets the d-axis current Id of the motor 1 to 0, and the q-axis voltage (q-axis drive voltage) Vq ^* is adjusted so that the d-axis current does not excessively occur in the positive direction. By adjusting , the generation of surplus power can be suppressed. Further, the speed at which the motor 1 can be rotated can be ensured 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, the q-axis voltage having the same magnitude as the d-axis voltage used in the rotor positioning step is used as the initial q-axis voltage V0, so that the motor 1 voltage generated in the rotor positioning step of the motor 1 is The drive torque and the drive torque at the start of the synchronous operation step can be made the same, so that the rotor alignment step can be smoothly transitioned to the synchronous operation step.

Further, according to the first embodiment, it is determined whether or not the motor 1 has reached a speed at which the axis error Δθ can be calculated. Since the mode is shifted from the synchronous operation step to the normal operation, it is possible to prevent mode transition failure due to insufficient acceleration of the motor 1 .

(Modification of Embodiment 1)
In the first embodiment described above, the estimated current speed of the motor 1 is the speed at which the d-axis current Id is zero. However, the present speed of the motor 1 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 the load during normal operation of the motor 1 . The load of this motor 1 is a small compressor. On the other hand, if the start-up control of the first embodiment is executed with a large compressor as a load, a larger load than expected for 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 approximately six times as large as the load applied to the motor 1 in the first embodiment during normal operation.

As described in the first embodiment, it is preferable that the current vector (d-axis current Id and 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 required to increase the rotation speed of the motor 1, but if the starting torque is insufficient, the rotation speed cannot be increased. If the number of revolutions does not increase, the motor will not be able to consume the power given to it, resulting in an increase in surplus power. If the surplus power increases, the d-axis current will flow in the positive direction. In the second embodiment, as in the first embodiment, the rotor speed estimated value estimated from the d-axis current is controlled to reach the speed command value. The estimated speed ωe (hereinafter sometimes referred to as “speed estimated value”) becomes large. As the estimated speed value increases with respect to the speed command value, the q-axis voltage acts to decrease according to the above equation (12). As a result, the starting torque cannot be increased, the rotation speed does not increase, the surplus power increases, and a large d-axis current flows in the positive direction, leading to a vicious circle. That is, if the current vector is placed in the first quadrant when the load torque is large at startup, the startup torque is controlled to decrease. In addition, in a state in which sufficient driving torque cannot be secured, it may be difficult to smoothly shift the mode from the synchronous operation step to the normal operation. For example, when a load five times the normal load is applied to the motor 1 in the first embodiment, it may be difficult to smoothly shift the mode from the synchronous operation step to the normal operation in the first embodiment. be.

Therefore, while the d-axis voltage Vd is fixed at 0 in the above-described first embodiment, the d-axis voltage Vd is set to a negative voltage so that sufficient starting torque can be applied to the load torque in the second embodiment. and Although this voltage is described as a variable voltage in this embodiment, it is not limited to this, and may be a predetermined fixed voltage.

(Configuration of motor control device in synchronous operation step according to Embodiment 2)
In Embodiment 2, instead of the configuration of the motor control device in the synchronous operation step according to the basic configuration of FIG. FIG. 9 is a diagram showing an example of the configuration of the motor control device in the synchronous operation step according to the second embodiment.

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

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

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 by the 3φ/dq converter 25 and the electrical angle estimated speed ωe output by the speed estimator 29B. It is 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. In the following, 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.

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

When starting when a large load torque is generated, the estimated speed value increases as the d-axis current increases in the positive direction. As the estimated speed value increases with respect to the speed command value, the q-axis voltage acts to decrease according to the above equation (12). As a result, the starting torque cannot be increased, the rotation speed does not increase, and surplus electric power increases, causing a large d-axis current to flow in the positive direction.

On the other hand, according to the above equation (2), if the d-axis voltage is controlled so that the d-axis current becomes 0, even if the motor 1 starts when a large load torque is generated, the d-axis current is An increase in the positive direction is suppressed, and the estimated speed value does not become excessively large. If the estimated speed value does not increase with respect to the speed command value, the q-axis voltage does not work to decrease, and the q-axis current for normally applying the required starting torque can flow.

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

On the other hand, unlike the case of Vd=0 in the first embodiment, adding control of the d-axis voltage as in the above equation (13) causes interference between the d-axis and the q-axis. Therefore, it is preferable that each of the d-axis and q-axis voltage generators 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 the non-interference term as it is, so the influence of the interference on the q-axis side can be canceled. On the other hand, for the q-axis voltage, the first and second terms on the right side of the above equation (12) are directly non-interfering terms, so the influence of interference on the d-axis side can be canceled. Therefore, the d-axis and q-axis voltage generators can generate non-interfering voltage command values.

The q-axis voltage generator 17B generates the d-axis current Id output by the 3φ/dq converter 25, the estimated electrical angle speed ωe output by the speed estimator 29B, the initial electrical angle speed ωe0 of the motor 1, q The q-axis voltage command value Vq ^* in the synchronous operation step is generated from the electrical angular velocity command value ωe ^* generated inside the axis 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 starting torque by setting the q-axis voltage having the same magnitude as the d-axis voltage during positioning in the rotor positioning step as the initial q-axis voltage V0. The q-axis voltage generator 17B generates an appropriate q-axis voltage Vq for increasing the speed of the motor 1, and controls surplus power to a minimum, thereby enabling mode transition from the synchronous operation step to normal operation. At the same time, a speed sufficient to generate the induced voltage necessary for calculating the axis error Δθ in normal operation is ensured.

The speed estimator 29B has the same configuration as the speed estimator 29X according to the basic form, but the electric angle An 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 estimator that estimates the current speed from the d-axis current in the dq coordinate system of the current detected by the detector.

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

The multiplier 16B-1 receives the estimated electrical angle speed ωe, the q-axis current Iq, and the q-axis inductance Lq as inputs, and multiplies the result of multiplication of the estimated electrical angle speed ωe, the q-axis current Iq, and the q-axis inductance Lq to the subtractor 16B-1. Output to 2. The subtractor 16B-2 calculates the deviation (0-ωeLqIq) between 0 and the output of the multiplier 16B-1 to make the result of the multiplication by the multiplier 16B-1 a negative value. 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 used instead of the subtractor 16B-2. The output of 16B-1 may be multiplied by -1. Further, the estimated electrical angle speed ^ωe is input to the multiplier 16B-1. , the electrical angular velocity command value ωe ^* may be input to the multiplier 16B-1.

As described above, the d-axis voltage Vd (d-axis drive voltage Vd) output by 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 the 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.

(Processing of synchronous operation step according to Embodiment 2)
The processing of the synchronous operation step according to the second embodiment is the same as the processing 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 the d-axis current input to 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 reaching speeds of the electrical angular velocity command value ωe ^* and the estimated electrical angular velocity ωe in the second embodiment are the same as in the first embodiment.

(Transition of each value according to Embodiment 2)
11A to 14B, regarding Embodiment 2 and Embodiment 1, changes in d-axis current and q-axis current, changes in d-axis voltage and q-axis voltage, and changes in d-axis voltage and q-axis voltage when the motor load is large. The transition of the axis error Δθ, the transition of the estimated electrical angle speed and the speed command value will be compared and explained.

In FIGS. 11A to 14B, the section (1) dividing the time t on the horizontal axis is the rotor positioning step section, the section (2) is the synchronous operation section, and the section (2) is further divided. The section (2)' indicates the section of the acceleration region toward the target speed, and the section (2)" indicates the section of the constant speed region after reaching the target speed. The section of the acceleration region is the command speed. 11A, 12A, 13A, and 14A are sections in which the command speed is constant, and section (3) in FIGS. show.

(Changes in d-axis voltage and q-axis voltage and changes in d-axis current and q-axis current in Embodiment 2 when motor load is large (FIGS. 11A and 12A))
FIG. 11A is a diagram showing an example of changes in d-axis current and q-axis current according to the second embodiment when the load on the motor is large. FIG. 12A is a diagram showing an example of changes in 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 . As a result, the d-axis current Id flows through the motor 1 in the rotor positioning step (1), as shown in FIG. 11A.

Next, in the second embodiment, as shown in FIG. 12A, in the acceleration region (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 q-axis voltage Vq thus obtained is applied to the motor 1 . Then, in the acceleration region of (2)′, while the d-axis voltage Vd gradually decreases, the magnitude of increase in the q-axis voltage Vq becomes greater than the magnitude of decrease in the d-axis voltage Vd. 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)′, the q-axis voltage Vq calculated based on the above equation (12) is expressed by the above equation (12) The integral terms of the second and third terms of work to converge to the optimum q-axis voltage. Although the voltage Vq is small, it turns to decrease. Moreover, 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 speed, and the convergence time for converging to the q-axis voltage appropriate for the rotation speed has elapsed, and the motor At the timing t1 when the estimated electrical angle speed ωe of 1 reaches the target speed, the mode is changed from the synchronous operation step of the motor 1 to the normal operation.

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

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 . As a result, the d-axis current Id flows through the motor 1 in the rotor positioning step (1), as shown in FIG. 11B.

Next, in Embodiment 1, as shown in FIG. to be printed. However, when the load of the motor is large, in the first embodiment, as shown in FIG. end up This is because, as shown in FIG. 14B described later, the estimated electrical angle speed ωe becomes difficult to follow the target electrical angle speed ωe ^* in the second half of the acceleration region of (2)′, and the speed increases. This is because the q-axis voltage Vq decreases in an attempt to decrease the speed. Accordingly, as shown in FIG. 11B, in the second half of the acceleration region of (2)′, the q-axis current Iq cannot be controlled and the q-axis current Iq decreases, and the d-axis current Id is controlled. also become 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 showing an example of transition of the axis error Δθ according to the second embodiment when the motor load is large. 13B is a diagram showing an example of transition of the axis error Δθ according to the first embodiment when the motor load is large. FIG.

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

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

(Changes in estimated electrical angle speed and target electrical angle speed in Embodiment 2 and Embodiment 1 when motor load is large)
FIG. 14A is a diagram showing an example of changes in the estimated electrical angle speed and the target electrical angle speed according to the second embodiment when the load on the motor is large. 14B is a diagram showing an example of changes in the estimated electrical angle speed and the target electrical angle speed according to the first embodiment when the load on the motor is large; FIG.

As shown in FIG. 14A, in the second embodiment, the estimated electrical angular velocity ωe is the electrical angular velocity command value (that is, the electrical angular target speed) ωe ^* and accelerates.

In contrast, in the first embodiment, as shown in FIG. 14B, the estimated electrical angular velocity ωe follows the electrical angular velocity command value ωe ^* (that is, the electrical angular target velocity) in the second half of the acceleration region of (2)′. becomes uncontrollable, and 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 showing an example of an ideal relationship between the dq-axis current vector and the γδ-axis current vector. FIG. 16 is a diagram showing 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 showing an example of the relationship between the dq-axis current vector and the 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 most rotational force is applied to the rotor. Also, the state in which the direction of the current vector I _γδ 0 on the γδ axis is the same as the direction of the current vector I _dq 0 is the state in which the axis error Δθ is 0, which is an ideal state.

On the other hand, in the case of the first embodiment, as shown in FIG. 16, the load of the motor 1 causes the axis error Δθ1, so that the direction of the current vector I _γδ 0 changes from the direction of the current vector I _dq 0. Δθ1 advances too much. In contrast, 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). As a result, in the first embodiment, the direction of the current vector I _γδ 0 whose direction has advanced too far can be returned by the amount of the axis error Δθ1 like the current vector I _γδ 1 shown in FIG _. 1 can be kept in the first quadrant of the dq coordinate. However, in Embodiment 1, the direction of the current vector on the γδ axis can be changed, but the magnitude is not changed. Further, when the γ axis is 0 degrees and the δ axis is 90 degrees, in the first embodiment, the control width of the current vector on the γ δ axis is in the range of 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 I _γδ can be increased from 0. Therefore, in the second embodiment, even when the load on the motor 1 is large, the axis error can be made smaller than in the first embodiment (Δθ2<Δθ1). Further, in the second embodiment, as in the first embodiment, the q-axis voltage Vq ^* is controlled according to the above equation (12). Therefore, in the second embodiment, the direction of the current vector I _γδ 2A whose direction is too advanced can be returned by the amount of the axis error Δθ2 like the current vector I _γδ 2B shown in FIG. Similarly, we can keep the current vector I _γδ 2B in the first quadrant of the dq coordinate. However, in the second embodiment, since the d-axis voltage Vd is calculated according to the above equation (13), when the γ-axis is 0 degrees and the δ-axis is 90 degrees, the control width of the current vector on the γ-δ-axis is from 90 degrees to The range is 80 degrees, which is smaller than in the first embodiment. However, in the second embodiment, since the axis error is smaller than in the first embodiment by calculating the d-axis voltage Vd according to the above equation (13), the control width of the γδ-axis current vector is smaller than in the first embodiment. A 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 the d-axis voltage calculated according to the above equation (13), for example. Therefore, in the second embodiment, even when the load of the motor 1 is larger than in the first embodiment, it is possible to control the q-axis voltage equivalent to that in the first embodiment while obtaining the required torque.

The second embodiment has been described above.

The specific names, processes, controls, and information including various data and parameters in the above embodiments and illustrations are only examples, and can be changed as appropriate unless otherwise specified. Also, the configuration of each unit or each device in the above-described embodiments may be appropriately distributed or integrated in consideration of the processing load, implementation efficiency, and the like. Further, each process in the above-described embodiments may be executed by appropriately changing the order of the processes in consideration of the processing load, implementation efficiency, and the like.

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

2X, 2A, 2B controllers 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 Ψ multiplier 17A-6 adder 17A-7 adder 17A-8 electrical angular velocity Command generator 18 Non-interfering 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 arithmetic processor 29 PLL controllers 29X, 29A, 29B speed estimator 29X-1 proportional term calculator 29X-2 integral term calculator 29X-3 adder 30, 30X position estimator 31 1/Pn processors 100X, 100A, 100B motor controllers CO0, CO1, CO2 contact SW1 switch

Claims (2)

a driving unit for driving the motor by supplying a driving voltage generated based on the difference between the target speed of the motor and the current speed of the motor to the motor;
a detection unit that detects the current flowing through the motor;
a speed estimation unit for estimating the current speed from the d-axis current in the dq coordinate system of the current detected by the detection unit;
a d-axis voltage generator for generating a d-axis drive voltage as the drive voltage for the d-axis in the dq coordinate system;
a q-axis voltage generator that generates a q-axis drive voltage as the drive voltage for the q-axis in the dq coordinate system;
a drive voltage generator 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 generator outputs an initial drive voltage, and then generates the q-axis drive voltage from at least the initial drive voltage, the target speed, and the current speed,
The d-axis voltage generator generates the d-axis drive voltage as −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 ), and
The q-axis voltage generator generates the q-axis drive voltage from the following equation (1),
motor controller.

However, in the above equation (1), "Vq ^* " is the q-axis drive voltage, "ωe ^* " is the target speed, "ωe0" is the electrical angular initial speed of the motor, and "Ld" is the d-axis of the motor. "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 integration interval of the right side of the above equation (1) is the time from the start of the synchronous operation of the motor to the present time. a driving unit for driving the motor by supplying a driving voltage generated based on the difference between the target speed of the motor and the current speed of the motor to the motor;
a detection unit that detects the current flowing through the motor;
a speed estimation unit for estimating the current speed from the d-axis current in the dq coordinate system of the current detected by the detection unit;
a d-axis voltage generator for generating a d-axis drive voltage as the drive voltage for the d-axis in the dq coordinate system;
a q-axis voltage generator that generates a q-axis drive voltage as the drive voltage for the q-axis in the dq coordinate system;
a drive voltage generator 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 generator outputs an initial drive voltage, and then generates the q-axis drive voltage from at least the initial drive voltage, the target speed, and the current speed,
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.
motor controller.

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