JP6562881B2 - Constant identification apparatus and constant identification method for permanent magnet synchronous motor - Google Patents

Description

  Embodiments of the present invention relate to an apparatus and method for identifying the moment of inertia of a permanent magnet synchronous motor.

For example, when PI (Product-Integral) control of the motor speed is performed, the moment of inertia of the motor and the load connected to the motor is required to quantitatively determine the control gain. Conventionally, as disclosed in Patent Document 1, a motor torque T _M obtained by calculating the speed variation width dω at the time of accelerating the motor, and identifying the moment of inertia J _M by equation (1). Since the load torque T _LOAD is often unknown, the load torque T _LOAD is identified by performing a test operation of two or more conditions.

J _M (dω / dt) = T _M −T _LOAD (1)

Japanese Patent No. 3731060

However, in the conventional technique, in order to determine the control gain used for speed control, the motor is operated without controlling the speed, and the moment of inertia is identified. For example, it performs acceleration corresponding to the difference torque between the load torque T _LOAD to control the motor torque T _M constant, determining the moment of inertia at a speed range of change in time. In this case, if the load torque moment of inertia unknown, or the motor is rapidly accelerated by the motor torque T _M given, there is a possibility of falling into overspeed condition. Depending on the structure of the mechanical system to which the motor is connected, the operation itself may be a problem.

Or, if you do not know the exact moment of inertia but the speed control gain is fixed, you may be able to identify the moment of inertia while performing a certain amount of speed control. The question remains as to whether to decide.
Furthermore, assuming that the speed of a permanent magnet synchronous motor is controlled in a position / speed sensorless configuration, if the motor is suddenly accelerated and the rotational speed exceeds the control band of the position sensorless control system, sensorless control will fail. Cause a tonal phenomenon.

  Therefore, a constant identification device for a permanent magnet synchronous motor and a constant identification method for a permanent magnet synchronous motor that can identify the moment of inertia so that an unexpected sudden acceleration or over-rotation state does not occur even under conditions where the load torque and the inertia moment are unknown. I will provide a.

Permanent magnet synchronous motor constant identifying unit in the embodiment, based on the d _c-axis is the estimated axis of the permanent magnet flux direction in the rotor of the permanent magnet synchronous motor, wherein to determine the voltage or current applied to the motor A constant identification unit is provided for performing synchronous pull-in driving when starting the motor and identifying the magnet magnetic flux and the moment of inertia within the period during which the synchronous pull-in driving is performed.
When the constant identification unit performs positioning of the rotor, the constant identification unit increases the rotation speed of the motor to perform first pull-in synchronous driving,
Then providing a period for maintaining the rotational speed at a constant value, the magnetic flux phi _f based on the axis error [Delta] [theta] _c between the d-axis is d _c axis and the axis of the permanent magnet flux direction within the period Identify and
Then performs a second synchronization pull drive is raised again the rotational speed, or the axis error [Delta] [theta] _c is equal to or less than a predetermined value, and / or fixed time identified elapses the moment of inertia J _M.
Further, according to the constant identifying device of a permanent magnet synchronous motor embodiments, the constant identifying unit, the axis error estimating the axis error [Delta] [theta] _c between the d-axis is an axis of d _c axis and the permanent magnet flux direction An estimation unit;
A magnetic flux identification unit for identifying the magnet magnetic flux φ _f based on the axial error Δθ _c ;
Based on the axis error [Delta] [theta] _c and the magnetic flux phi _f, and the motor torque identifying unit for identifying the motor torque T _M,
A load torque identification unit for identifying a load torque T _LOAD based on the axis error Δθ _c and the magnet magnetic flux φ _f ;
On the basis of the motor torque T _M and the load torque T _LOAD, and a moment of inertia identification unit to identify the moment of inertia J _M.

1 is a functional block diagram showing the configuration of a motor constant identification device according to an embodiment Functional block diagram showing the configuration of the constant identification unit Flow chart showing processing contents of motor constant identification device The figure which shows the operation waveform of each part corresponding to the processing content in each step of FIG. diagram showing the relationship between the dq axis and the _d c _{q c} axis

  Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a functional block diagram showing the configuration of the motor constant identification device. The direct current power supply unit 1 is indicated by a direct current power supply symbol. When the direct current power supply is generated from a commercial alternating current power supply, it includes a rectifier circuit, a smoothing capacitor, and the like. An inverter circuit 3 is connected to the DC power supply unit 1 through a positive bus 2a and a negative bus 2b. The inverter circuit 3 is configured by connecting, for example, N-channel type power MOSFETs 4 (U +, V +, W +, U−, V−, W−) as a switching element in a three-phase bridge, and the output terminal of each phase is a motor. 5 is connected to each phase winding.

A current sensor 6 is inserted between each phase output terminal of the inverter circuit 3 and each phase winding of the motor 5, and a sensor signal of the current sensor 6 is input to the current detection unit 7. The current sensor 6 may be a current transformer using a Hall IC or a shunt resistor inserted on the lower arm side of the inverter circuit 3. The current detection unit 7 performs A / D conversion on the input sensor signal, reads it, performs necessary signal processing, and outputs the currents I _u , I _v , and I _w of the U, V, and W phases. These phase currents are input to the three-phase / d _c q _c conversion unit 8.

In 3-phase _/ d c _{q c} conversion unit 8, the phase currents _I u _inputted, I v, _{I w} is converted _{d c-axis} current _I dc, the _{q c-axis} current _{I qc.} d _c-axis, the q _c-axis, as shown in FIG. 5, the axis coincides with the direction of the permanent magnet magnetic flux estimated by calculation is d _c-axis, the axis orthogonal to the d _c-axis is a q _c axis . Between the d-axis match the d _c axis and the true magnetic flux direction, there is a position error [Delta] [theta].

The shaft currents I _dc and I _qc are input to the constant identification unit 9 and the current control unit 10. D _c-axis voltage V _dc from the current controller 10 to the constant identifying unit _9, q _c-axis voltage V _qc is input, constant identifying unit 9, the armature interlinkage from each calculation parameters input phi _f , to identify the moment of inertia _{J M.} Further, in the course of performing its identification, to determine the _{d c-axis} current command _{I dc_ref, q c-axis} current command _{I Qc_Ref} and the rotation speed command value omega _Ref of the motor 5. The current commands I _{dc_Ref} and I _{qc_Ref} are input to the current control unit 10. Also, the speed command value omega _Ref, the integrator 11 is integrated and converted into position command theta _Ref by its position command theta _Ref is 3-phase _/ d c _{q c} converter 8 and _d c _q c / 3-phase conversion Input to the unit 12.

The current control unit 10, the axis current _{I dc,} calculated _{I qc} is the -axis current _{I dc_ref, d c-axis} voltage _V dc to follow the _{I Qc_Ref,} the _{q c-axis} voltage _{V qc,} constant identifying unit 9 And _dc q _c / 3 phase conversion unit 12. d _c q _c / 3-phase conversion unit 12, two-axis voltage _{V dc,} converts the _{V qc} 3-phase voltage command _{V u,} V v, the _{V w,} and outputs the duty generation unit 13. The voltage detector 15 detects the voltage V _DC of the DC power supply 1 and outputs it to the duty generator 13. The duty generation unit 13 divides the three-phase voltage command values V _u , V _v , and V _w by the direct-current voltage V _DC to determine the duties D _u , D _v , and D _w for generating each phase PWM signal, Input to the PWM generator 14.

For example, a triangular wave-shaped PWM carrier is input to the PWM generation unit 14, and the PWM generation unit 14 compares the levels of the carrier and the respective phase duties D _u , D _v , and D _w to compare the three-phase PWM signals U +, V + and W + are generated. Further, signals U−, V−, W− on the lower arm side obtained by inverting the three-phase PWM signal are also generated, and after a dead time is added as necessary, they are output to the inverter circuit 3. In the above, the functions of configurations 7 to 14 are functions realized by hardware and software of a microcomputer including a CPU.

Next, the identification principle and sequence of the armature flux linkage φ _f and the moment of inertia J _M in the constant identification unit 9 of this embodiment will be described with reference to FIGS. It is assumed that it is possible to control the motor current according to the current command value. This is because, generally, when the motor is stopped, the gain of current control can be adjusted based on the identification of the resistance and inductance of the stator winding.

Figure 3 is a flow chart illustrating processes to identify armature flux linkage phi _f and moment of inertia J _M. FIG. 2 is a diagram showing each processing block of the constant identification unit 9 corresponding to the processing content. First, the values in the _{d c-axis} current, for example, a _{I dc1, q c} axis current do "positioning operation" of the rotor by controlling the current so as to 0A (S1). The rotation speed command ω _Ref is set to zero. Accordingly, the rotation angle command θ _Ref that is the integral of the rotation speed command is also 0 deg. At this time, if the initial magnetic pole position θ of the rotor is other than 0 deg, the magnetic pole position θ is attracted to the position of 0 deg by the energized current.

Here, the magnetic pole position error Δθ when the rotation angle command θ _c (= θ _Ref ) and the magnetic pole position θ are given is given by equation (2).
Δθ = θ−θ _c (2)
d _c-axis current command _{I dc_ref,} from the magnetic pole position error [Delta] [theta], the torque _{T M} of the motor 5 is generated is given by equation (3).・
T _M = Pφ _f I _{dc_Ref} sin Δθ (3)
However, P is the number of motor pole pairs.

As shown in (3), if there is a magnetic pole position error [Delta] [theta], the motor 5 produces a torque T _M, the torque T _M is also zero when the error [Delta] [theta] is zero. That is, if the initial magnetic pole position θ does not coincide with θ _Ref , torque _TM is generated until both coincide with each other, and the magnetic pole position θ is positioned at the rotation angle command θ _Ref .

When the positioning operation is completed as described above, the forced synchronous drive (1) is executed (S2). Forced synchronous drive (1) corresponds to first pull-in synchronous drive. In the forced synchronous drive, the motor 5 is accelerated by moving the rotation angle command θ _Ref while performing the same control as the positioning operation. The rotation angle command θ _Ref is given by integration of the rotation speed command ω _Ref as shown in equation (4). Note that “s” in the equation (4) is a differential operator.
θ _Ref = ω _Ref / s (4)

This operating principle is similar to positioning, if where there is a load torque T _Load, the motion equation of the motor is a (1) represents a torque T _M (3) in equation rotational speed command omega _Ref And the rotational speed ω substantially coincide with each other, the equation of motion of the motor can be expressed by equation (5).
J _M (dω _Ref / dt) = Pφ _f I _{dc_Ref} sin Δθ−T _LOAD (5)
In (5), when there is a load torque T _LOAD or speed variation d [omega _Ref, unless there is a magnetic pole position error [Delta] [theta], it is not possible to rotate the motor 5 to generate torque T _M.

尚、図２に示す位置誤差推定部２１は、推定値Δθ_ｃを求める処理ブロックである。 In this state, when the rotational speed command ω _Ref reaches ω _Ref1 (S3; YES), the motor 5 is controlled to operate at a constant speed to identify the armature linkage magnetic flux φ _f (S4). Here estimate [Delta] [theta] _c of the magnetic pole position error [Delta] [theta] can be determined by using the voltage and current of the d _c q _c axis (6).

2 is a processing block for obtaining the estimated value Δθ _c .

図２に示す磁束同定部２２は、磁束φ_ｆを同定する処理ブロックである。 Further, since the voltage equation of the dq axis in the steady state when rotating at the rotational speed command ω _Ref is the equation (7), and the armature linkage magnetic flux φ _f is on the q axis side, the equation (7) It can be identified magnetic flux φ _f using.
V _d = RI _d −ωL _q I _q
V _q = RI _q + ωL _d I _d + ωφ _f (7)
(7) is represented by dq axis is actually the voltage and current of the d _c q _c-axis can be detected. (7) the expression of the q-axis side of the magnetic flux phi _f, the expressed at d _c q voltage and current of the _c-axis and the magnetic pole position error estimation value [Delta] [theta] _c (8) formula. Identifying flux phi _f using the equation (8).

Flux identifying section 22 shown in FIG. 2 is a processing block to identify the magnetic flux phi _f.

Also, the current load torque T _LOAD is identified during the constant speed operation in step S4. In equation (5), since the speed is constant, if the speed change dω _Ref is zero, the load torque T _LOAD can be identified by equation (9) using the magnetic flux φ _f identified in equation (8).
T _LOAD = Pφ _f I _{dc_Ref} sin Δθ _c (9)
The load torque identification unit 24 illustrated in FIG. 2 is a processing block that identifies the load torque T _LOAD .

Next, the motor 5 is accelerated again to execute forced synchronous drive (2) (S5). Forced synchronous drive (2) corresponds to second pull-in synchronous drive. The acceleration at this time is set higher than in the case of step S2, and the speed command ω _Ref is changed from ω _Ref1 to ω _Ref2 to accelerate. The identifying inertia _{J M} during acceleration (S7). When deformed again using equation (5), equation (10) is obtained. Here, dt is an acceleration time from the speed command ω _Ref1 to ω _Ref2 , and dω _Ref is obtained by (ω _Ref2 −ω _Ref1 ). The load torque T _LOAD uses the value identified in step S3.

The estimated value Δθ _c of the magnetic pole position error used here is calculated using equation (6) during the acceleration operation in step S5. Since the estimated value Δθ _c immediately after the start of acceleration has a large amount of fluctuation, after a certain time has elapsed after the start of acceleration, or when the estimated value Δθ _c becomes equal to or less than a certain value (S6; YES), or The value after satisfying both conditions is used. Furthermore, an average value of the estimated value Δθ _c during the acceleration period may be used. The motor torque identification unit 23 and the inertia moment identification unit 25 are processing blocks that identify the motor torque T _M and the inertia moment J _M.

The moment of inertia J _M can be identified by the above process. In this way, by using forced synchronous drive and pull-in synchronous drive and performing identification using the estimated value Δθ _c of the magnetic pole position error at that time, it is a stage before adjusting the speed control of the motor 5, which is position sensorless. Even in a configuration that employs control, identification is possible while managing the speed and acceleration of the motor 5.

FIG. 4 shows an operation waveform of each part corresponding to the processing content in each step of FIG. After performing the positioning operation in step S1, the rotational speed ω is increased by the forced synchronous drive (1) in step S2. During this time, _{d c-axis} current Id _c is flowing command value _I dc1 = 3A. The q _c- axis current is the command value 0A. The load torque T _LOAD is 0.5 Nm. For this reason, the magnetic pole position error Δθ is generated as much as the torque T _LOAD can be output.

The estimated value Δθ _c of the magnetic pole position error is a calculated value and a slight noise component is superimposed on it, but it can be estimated to approximately the same level. Using this, the armature flux linkage φ _f is estimated in step S4. In the acceleration period of step S5 and forced synchronous drive (2), the magnetic pole position error Δθ further increases due to the acceleration torque. By estimating the torque generated by this, to identify the moment of inertia J _M at step S7.

According to this embodiment as described above, constant identifying unit 9, based on the d _c-axis is the estimated axis of the permanent magnet flux direction disposed on a rotor of the permanent magnet motor 5, is applied to the motor 5 Pull-in synchronous drive when starting the motor 5 by determining the voltage or current is performed, and the magnet magnetic flux φ _f and the moment of inertia J _M of the motor 5 are identified within the period during which the pull-in synchronous drive is performed. Specifically, based on the axis error [Delta] [theta] _c between the d-axis is the axis of d _c axis and the permanent magnet flux direction, and a magnetic flux phi _f and moment of inertia J _M (8) and (10) Identify.

More specifically, when the constant identification unit 9 positions the rotor in step S1, the constant identification unit 9 performs the forced synchronous drive (1) by increasing the rotational speed of the motor 5, and then maintains the rotational speed at a constant value. the period provided to identify the magnetic flux phi _f in step S4 in the period. Then the rotational speed is increased again to force synchronous drive (2), or the estimated value [Delta] [theta] _c of the magnetic pole position error is below a predetermined value, and / or a predetermined time to identify to the moment of inertia J _M elapsed.

Moreover, constant identifying unit 9 the axis error [Delta] [theta] _c between the d-axis is the axis of d _c axis and the permanent magnet flux direction estimated by the axis error estimator 21, the magnetic flux identification unit 22 based on the axis error [Delta] [theta] _c The magnetic flux φ _f is identified. Then, when the motor torque identification unit 23 and the load torque identification unit 24 identify the motor torque T _M and the load torque T _LOAD based on the axis error Δθ _c and the magnet magnetic flux φ _f , the inertia moment identification unit 24 detects the motor torque T _The moment of inertia J _M is identified based on _M and the load torque T _LOAD .

As a result, in the system for controlling the speed of the permanent magnet synchronous motor 5 with the position / speed sensorless configuration, identification is performed while controlling the acceleration and speed of the motor 5 even under conditions where the load torque T _LOAD and the moment of inertia J _M are unknown. In the identification process, unexpected sudden acceleration and excessive rotation can be avoided.

(Other embodiments)
The constant identification device may be configured in common with a control device that controls the normal operation of the motor.
Although several embodiments of the present invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawing, 5 is a permanent magnet synchronous motor, 9 is a constant identification unit, 21 is a magnetic flux identification unit, 22 is a load torque identification unit, 23 is a position error estimation unit, 24 is a motor torque identification unit, and 25 is an inertia moment identification unit. Show.

Claims (3)

Based on the d _c-axis is the estimated axis of the permanent magnet flux direction disposed on a rotor of a permanent magnet motor, the pull-in driving at the time of starting the motor to determine the voltage or current applied to the motor A constant identification unit for identifying the magnet magnetic flux φ _f and the moment of inertia J _{M of the} motor within a period during which the pull-in synchronous drive is performed ,
When the constant identification unit performs positioning of the rotor, the constant identification unit increases the rotation speed of the motor to perform first pull-in synchronous driving,
Then providing a period for maintaining the rotational speed at a constant value, the magnetic flux phi _f based on the axis error [Delta] [theta] _c between the d-axis is d _c axis and the axis of the permanent magnet flux direction within the period Identify and
Then performs a second synchronization pull drive is raised again the rotational speed, the permanent magnets the axis error [Delta] [theta] _c is you identify the moment of inertia J _M whether falls below a predetermined value, and / or a predetermined time has elapsed Constant identification device for synchronous motor. Based on the d _c-axis is the estimated axis of the permanent magnet flux direction disposed on a rotor of a permanent magnet motor, the pull-in driving at the time of starting the motor to determine the voltage or current applied to the motor A constant identification unit for identifying the magnet magnetic flux φ _f and the moment of inertia J _{M of the} motor within a period during which the pull-in synchronous drive is performed ,
The constant identifying unit, and the axis error estimator that estimates the axis error [Delta] [theta] _c between the d-axis is the axis of the d _c axis and the permanent magnet flux direction,
A magnetic flux identification unit for identifying the magnet magnetic flux φ _f based on the axial error Δθ _c ;
Based on the axis error [Delta] [theta] _c and the magnetic flux phi _f, and the motor torque identifying unit for identifying the motor torque T _M,
A load torque identification unit for identifying a load torque T _LOAD based on the axis error Δθ _c and the magnet magnetic flux φ _f ;
A constant identification device for a permanent magnet synchronous motor , comprising: an inertia moment identification unit that identifies the inertia moment J _M based on the motor torque T _M and the load torque T _LOAD . Based on the dc axis that is the estimated axis of the permanent magnet magnetic flux direction arranged in the rotor of the permanent magnet motor, the voltage or current to be applied to the motor is determined, and the synchronous driving when starting the motor is performed. A constant identification method for a permanent magnet synchronous motor that identifies the magnet magnetic flux and the moment of inertia of the motor within a period during which the pull-in synchronous drive is performed ,
A first step of positioning the rotor;
A second step of increasing the rotational speed of the motor and performing a first pull-in synchronous drive;
Providing a period for maintaining the rotation speed at a constant value, and a third step of identifying the magnet magnetic flux within the period;
A fourth step of increasing the rotational speed again and performing second pull-in synchronous driving;
A constant identification method for a permanent magnet synchronous motor, comprising: a fifth step of identifying the moment of inertia when the axial error Δθ _c becomes equal to or less than a certain value and / or when a certain time elapses .

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