JPH037084A - AC rotating machine control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) The present invention relates to a control device for an AC rotating machine that can operate the AC rotating machine at variable speed with high efficiency, and particularly to The present invention relates to a control device for an AC rotating machine that aims to further improve controllability by correcting the amount of delay in the current that actually flows through the windings of the AC rotating machine (hereinafter referred to as actual current).

(Conventional technology) Conventionally, in order to operate AC rotating machines such as induction motors and synchronous motors as if they were DC rotating machines with high efficiency and variable speed over a wide range, it has been necessary to control not only the frequency and effective value of the actual current but also the rotation. A control device for an AC rotating machine has been proposed that controls even the phase of the actual current to the motor.

Table 1 of the control device for such an AC rotating machine has the following basic configuration. 6 is a block diagram of a control device that controls the speed of a three-phase synchronous motor 80. FIG. Synchronous electric [8
Actual current supplied to 0, i.e. three-phase armature current iu
, iv, iwl At least three phases are actually measured by the current coils 82a and 82b.The armature current of the remaining one phase is calculated from the detected values of the armature currents of the other two phases (for example, If, iw=-(i u+iv) ) will be done. Then, the detected armature current Ed-Q converter 84 converts the coordinates into a rotation coordinate (d-q coordinate) system determined on the rotor of the synchronous electric motor iJ%80. , the so-called q-axis component (1q) and the other invalid components, the so-called d-axis component (id).

Note that accurate information on the rotor magnetic pole position of the synchronous motor 80 is essential because the dq conversion unit 84 executes the coordinate conversion process. Therefore, a rotation angle sensor 86 is attached to the rotating shaft 80a of the synchronous motor 80 to detect the rotational state of the rotating shaft 80a. Magnetic pole position information is provided to the dQ converter 84.

The rotation angle sensor 86 also detects the rotation speed V of the rotation shaft 80a, and the detection result is used as feedback information.In other words, the rotation speed V is a negative feedback. Proportional/integral calculation section (P
I part) q of the actual current to be supplied to the synchronous motor via 88
It is used to calculate the target current value iq of the axis component. Then, in order to eliminate the deviation between the thus determined target current iq and the detected actual current value 1q of the q-axis component, the Vq calculation unit 90 It calculates the target q-axis component to be applied to the synchronous electric motor @80. Calculate the voltage Vq.

On the other hand, the target current of the d-axis component is 1d.
There is an optimum value for operating the motor with high efficiency, but this is an extremely small value, and for boat fishing it is approximated as "OJ". In order to eliminate the deviation from the actual current value 1d,
Target voltage Vd of the d-axis component to be applied to the synchronous motor 80
Determine.

When the target voltage Vq-Vd in the d-q coordinate system is determined in this way, the value is then inversely transformed in the d-q inverse converter 94 to obtain the three-phase AC voltage Vu actually applied to the synchronous motor.
, Vv, and Vw are determined. Then, in order to apply a voltage that is as close as possible to the determined AC voltage to each phase armature winding of the synchronous motor, power is supplied to the synchronous motor using a normal PWM type eraser 9 section 96. .

As described above, AC rotating machine control device 1. It is realized by executing complex control processing, and in order to realize it cheaply and easily, a software method using logical operation elements such as a microcomputer is adopted. That is, dq conversion and inverse conversion, calculation of various target voltages Vq., Vd., etc. are performed by software logical operations.

However, the speed required for logical operations by microcomputers, etc. is finite, and when the rotor rotates at high speed, that is, when the d-Q coordinate system changes in a short period of time, the delay in the logical operations causes a delay in actual current control. The influence becomes unignorable, and control performance deteriorates. Therefore, the following techniques are known to reduce the influence of this processing speed and improve control accuracy.

FIG. 7 (Table) This is a vector diagram for explaining the principle of calculating the target voltages vq-, Vd on the dq coordinate in FIG. winding - winding inductance per equivalent,
It represents the winding resistance.

Assuming that the actual current at a control sample point n at a certain point in time is in on the d-Q axis, the deviation from the target 'R current value 5q determined from the speed deviation amount is canceled and the next control sample point is At n+1, the actual current Ln is set to the target value L・(=?La
'n+Ld'n), ATL is
It is necessary to generate a current change of (:TIL・-已口). For this purpose, the voltage equation required to be applied to the winding is vn ('L).

Vn=RaXtn+(La/engineering)×△L+e...(1
) where e is a vector representation of the velocity electromotive force e on the dq axes.

In other words, if the above equation is divided into d-q components by the determinant and expressed ((2)) By solving this equation (2), the voltage Vn to be applied to the winding is
is determined.

However, it is impossible to complete calculations based on the above principle instantaneously, and a predetermined finite time is required.

Therefore, conventionally, the following series of processes 1 to 2 are executed.

■Detect the operating state of the synchronous motor t1!80 at sample point n-1, convert it to the d-Q coordinate system, and convert the actual current n-1,
Magnetic pole position information θn-1, speed electromotive force e n-1, and winding applied voltage Vn-1 are calculated.

(2) From these calculation results and equation (3) below, approximately estimate the actual current An on the d-q coordinates at the next sample point n.

However, it is assumed that Ra=O. (2) Using the estimated value, determine Vn on the d-q coordinates from the above equation (2).

(2) d-CI inverse transform of Vn is performed and output at sample point n.

As a result, the actual current L at the sample point n + 1
It becomes possible to control n+1 to match the target current of 5°.

(Problem to be Solved by the Invention) A control device for an AC rotating machine that estimates the actual current in and calculates the output Vn as described above (other calculations are performed using magnetic pole position information on-1 at the time of sample point n-1). The execution is performed on the dq coordinates determined by .

That is, in the d-Q coordinate system whose coordinate axes are dn-1 and qn-1 shown in FIG. 8, the sample point n
The current in at is predicted by the following equation (4), and Ln=Ln-1+△Ll-(4)
The winding applied voltage Vn that should produce a current change amount Δi2 such that this predicted value An matches the target current Lq at sample point n+1 is calculated, and as a result of the control execution, the current is at sample point n - )-1, the vector O
It becomes P.

However, if the amount of change in the position of the rotor is large during the control period until the above-mentioned processes ■ to ■ are completed, that is, if the synchronous motor 80 is rotating at high speed, the It, d-q coordinate system rotates. The coordinate axis of sample point n + 1 is d
n+1, q changes to n+1.

In other words, FF, LL At the time when the actual current control is executed, the above-mentioned vector OP rotates and changes to the vector OR.

In this way, when the rotational speed of the rotor is large compared to the control execution cycle, the control target and the actual rotational state differ greatly, resulting in a decrease in efficiency and control performance. This has led to a worsening of the situation.

The present invention has been made to solve the above problems, and enables highly efficient control at all times without deteriorating control accuracy not only in low-speed and medium-speed rotation states of an AC rotating machine but also in high-speed rotation states. The purpose of this invention is to provide a control device for an AC rotating machine.

Structure of the Invention (Means for Solving Section M) Means configured by the present invention to solve the above problems (Means for Solving Section M) As shown in the basic structural conceptual diagram of FIG. current supply means C1; current detection means C2 for detecting the actual current supplied by the current supply means C1; rotational position detection means C3 for detecting the rotational position of the rotor of the AC rotating machine M; and the rotational position thereof. a converting means C4 for converting the actual current 1 detected by the current detecting means C2 into a coordinate system determined on the rotor based on the rotational position of the rotor detected by the detecting means C3; and the converting means The deviation △1 between the actual current 1' coordinate-transformed by C4 and the target current 1 defined on the coordinate system is detected by the current detection means C2 and the rotational position detection means C3. A control device for an AC motor, comprising a control means C5 for determining a control amount to be decreased after a predetermined time from the start time and controlling the current supply means C1, wherein the amount of change in the rotational position of the rotor during the predetermined time is AC rotation characterized in that it is provided with an estimating means C6 for estimating, and a correcting means C7 for correcting the control amount determined by the control means C5 based on the rotational position change amount estimated by the estimating means C6. The gist of this is the machine's control system.

(Function) Estimating means C61 in the control device for an AC rotating machine of the present invention
1 Estimate the amount of rotational position change of the rotor within a predetermined time necessary to control the actual current 1 of the AC rotating machine M, and make it possible to grasp the state of the rotor at the time of executing the control of the actual current 1. .

Then, by the correction means C7, the coordinates of the actual current 1
The control amount for reducing the deviation Δ1 between ' and the target current 1° on the same coordinate system is corrected based on the rotational position change amount estimated by the estimating means C6.

That is, the estimating means C6 has the function of specifying the rotating coordinate system when executing the control, and the correcting means C7 has the function of converting the coordinates of the control amount necessary to reduce the actual current deviation into the rotating coordinate system when executing the control. It is played.

(Embodiment) FIG. 2 is a configuration block diagram of a control device 10 for an AC rotating machine which is an embodiment of the invention according to the present application.

As mentioned above, the configuration block diagram shown in Figure 2 (9)
This is a visual representation of the functions of the control device 10, and in order to realize this function, a software method using logic operation circuits centered on the microcomputer shown in FIG. 4 is used.

As can be easily understood visually from FIG. 2, the control device 101 of this embodiment has the same configuration blocks as the conventional control device shown in FIG.

Regarding these common structural blocks (other functions are also the same as those of the conventional one, the same reference numerals as in FIG. Has many common building blocks.

However, its common building block is the target current 5 (= iq
.+Ld.) to the synchronous motor 80. Then, the control device 1 of this embodiment
The i correction unit 20 newly provided at 0 changes the target current i as shown below, and the 81 child currents iu, iv supplied to the windings of the synchronous motor 80.
, iw are completely different from conventional control devices.

FIG. 3 (This is a vector diagram for explaining the function of the L L correction unit 20. As described above in FIG. 8, 1:
d-q coordinates at sample point n-1 (dn-1, qn-
1) Based on the above, predict the current Ln at the sample point n based on the actual current 1n-1 etc. at that time, and further predict the current Ln at the sample point n +1
Even if the amount of current change △tL2 is determined to match the target value Aq, the coordinate axes of the d-q coordinates actually change to dnil, qn+1 at the time of sample point n+1. . Therefore, even if control is executed to the synchronous motor [80] at the time of sample point n+1, the current actually supplied to the winding will be a current with a phase that is significantly delayed from the qn+1 axis at that point, and many invalid component (d n+1
Axis component) table will be included.

In order to solve this problem, the control device 10 of the present embodiment uses a d-q coordinate system (coordinate axis d n +
1. q n+1 ).

Therefore, the i° correction unit 20 converts the target current tq given from the d aNN elevation speed feedback system of sample point n-1 to the d=q coordinate system of sample point n+1, and adjusts the phase of the current. This compensates for delays in advance.

That is, the L correction unit 20 calculates the vector O8 and vector SR necessary for rotating the target current Lq (vector OP) in synchronization with the rotation speed of the dq coordinate system and making it match the vector OR. That's what I do. Here, the vector O8 is the q of the target current iq at the sample point q-1.
n-1 component, vector SR is d of target current 1q.
n-1 components, which can be calculated using the following equation (5) as can be visually understood from FIG.

... (5) Here, 280 is the angular difference between the d-q coordinate axis at sample point Q-1 and the d-Cl coordinate axis at sample point q+1, as shown in Figure 3. It is. That is, 1
It can be easily estimated from the rotation speed N at sample point n-1. Example (melon sample point n-1
Let the rotation speed be N [rpm], then the rotation angle △θ during the sample period is calculated from equation (6): 680 = XPX2π×d... (6)
0 However, P is the number of magnetic pole pairs.

In this way, the sample point n+1 is
The target current q・, 1d° converted to the d-Cl coordinate axis of
Once determined, the three-phase alternating currents iu, iv, i on the time axis that match the target currents 1q·, 1d° are applied to the synchronous motor 80 using the same configuration blocks as the conventional ones.
W can be understood.

FIG. 4 is a configuration diagram embodying the control device 10 of the configuration block diagram shown in FIG. It consists of an external circuit.

The logical operation circuit 30 has a general configuration, and includes a CPU 30a that executes logical operations, a ROM 30b that non-volatilely stores programs and trigonometric function tables to be described later,
It consists of a RAM 30c that temporarily stores information to assist the arithmetic processing of the CPU 30a, and an input/output board 30d that is responsible for exchanging information with external circuits.

External circuit (top) Inverter control circuit 32 for controlling the winding current of the synchronous motor 80, PWM type inverter 34
It also includes current detection coils 82a and 82b that detect the actual winding current flowing through the synchronous motor 80, an A/D converter 36, a rotation angle sensor 86 that detects the rotation angle of the synchronous motor 8o, and a counter 38.

R of the control device 10 adopting the above hardware configuration
OM30bl:fL As in the past, many programs listed below are stored.

The basic program is 1. First, A/D converter 3.
Progeran converts the three-phase winding current inputted from the counter 38 into d-q to calculate the current id, iq, and determines the target current 1 based on the input from the counter 38.The second calculated current id, iq and the determined target current value id”,
A voltage Vd- that eliminates the deviation from the deviation from iq.
Program to calculate vQ- And thirdly, the voltages Vd° and vq° calculated in the d-Q coordinate system are converted into the actual three-phase voltage V
There is a program that converts the signals into u, Vv, and Vw and creates a command signal to the inverter control circuit 32.6 Also, as a fourth program, the above basic program and the CPU 30a
A management program for managing the operating status of the fifth input/output boat 30d and inputting necessary information from external devices, or inputting/outputting input/output programs, etc. be.

Each of the above-mentioned programs is used to realize the same configuration blocks as the conventional control device in software in the functional block diagram shown in FIG. 2 of this embodiment, and is substantially the same as the conventional program. be. Therefore, detailed explanation thereof will be omitted here.

Further 1: In addition to the above programs, a new [Yo correction program] shown in FIG. (Voltage Vd- that eliminates current deviation,
target current value iq for the program that calculates VQ-
°, id". That is, the second B-
Correction program] is a program for implementing the functional block i° correction unit 20 shown in FIG. 2 in software.

This "L° correction program" (Table 1) is started after the above-mentioned first program is completed. That is, by processing the first program in the CPU 30a, the A/D
Detection of the actual currents id, iq and determination of the target current 1° are performed based on inputs from the converter 36 and the counter 38.
=The data is stored at a predetermined address in the RAM 30c.

Next, the CPU 30a1 table starts the process of ``rL-correction program'', accesses a predetermined address in the RAM 30c, and reads the target current i° (S100).Also, the rotation speed N of the synchronous motor 80 is updated and stored, so that it is always updated. The address where the latest rotational speed N data is stored is accessed to read the current rotational speed N (S110). Then, by substituting the data of the rotation speed N into the above equation (6), calculate the rotation angle difference of the d-q coordinate system within the control period T (S + 20), and use 〇 as a parameter for that value. Search the table prepared in advance in the ROM 30b in which the functions 5in (2△θ) and cos (2△θ) are written,
5n(2△θ) for the current rotation angle difference △θ, cos
The value of (2Δθ) is determined (S130).

In this way, when all the values to be substituted into the equation (5) are specified, the calculation of the equation (5) is executed to determine new target currents 1d., 1q. and,
The value 1dq· determined in this way is stored in a predetermined address of the RAM 30c (S150), and the processing of the [tL·correction program] is completed.

Once the final target currents id' and iqo are determined,
As in the conventional case, the applied voltage required to actually pass the target current to the synchronous motor 80 is calculated, and the data is output to the inverter control circuit 32 at a predetermined timing.

The control device 10 of the AC rotating machine of this embodiment configured as described above has the following effects. Estimate the d-q coordinates at the time when the actual current control of the synchronous motor 80 is actually executed from N, and synchronize the target current Lq with the rotational speed of the d-q coordinate system so that it matches the estimated coordinate system. The rotation angle of this d-q coordinate system can be estimated with extremely high precision.The control device 10 estimates the rotation angle of the d-Q coordinate system. This is because the time required for calculation is several m5 ec or less, and the synchronous motor 80, which has a large inertial force, does not suddenly change its rotational state during this short period.

Therefore, even if the d-q coordinate system defined on the rotor of the synchronous motor 80 rotates at a high speed that cannot be ignored relative to the control speed of the synchronous motor [80's high-speed rotation type IL, that is, the control device] 0, control cannot be executed. It becomes possible to pass the optimum actual current to the synchronous motor 80 at the time, and it is possible to completely follow the target rotational speed and torque. This makes it possible to control the synchronous motor 80 with high accuracy in all rotational ranges, including low floor, middle floor, and high speed, and exhibits control characteristics comparable to that of a DC motor.

This also means that the logical arithmetic circuit 30 constituting the control device 10 can be used to perform arithmetic processing at high speed without requiring a complicated configuration. This means that it is possible to construct a control system for a high-performance AC rotating machine that can withstand practical use.

It should be noted that the present invention is not limited to the configuration of the above-described embodiments, but may be embodied in various embodiments without departing from the gist thereof. For example, although the above embodiment shows an example in which a synchronous motor 8o is used as the controlled object, an induction motor or other AC motor may also be used.

Effects of the Invention As described above in detail with reference to embodiments, the control device for an AC rotating machine of the present invention estimates the amount of change associated with the rotation of the rotor in a finite time required to control the actual current, and uses the estimation result to Accordingly, there is an effect of passing the actual current in accordance with the true rotational position of the rotor during control execution.

Therefore, the control accuracy of the actual current becomes extremely high not only in the low- to medium-speed rotation range of the AC rotating machine but also in the high-speed rotation range, making it possible to precisely control the rotation speed and output torque. It can be controlled as if it were a DC motor.

[Brief explanation of the drawing]

FIG. 1 is a detailed explanation of the present invention. FIG. 2 is a block diagram explaining the functions of a control device according to an embodiment. FIG. Figure 4 is a configuration plate that realizes the functions of the same embodiment in software. Figure 5 is a flowchart of a program processed in the same embodiment. Figure 6 is a block diagram explaining the functions of a conventional control device. Figure 7 is the vector explaining the function of the conventional example. FIG. 8 shows the vector at high speed rotation according to the conventional example. 10...Control device 20...5° correction section 0...
・Logic operation circuit 32... Inverter control circuit 4...
・PWM type inverter 36...A/D converter 8...
・Counter 80...Synchronous motor 2a, 82b・
...Current coil 4...d-Q conversion section 86...Rotation angle sensor 8.
...Proportional/integral calculation section (PI section) O...vq calculation section 92...Vd calculation section 4...
d-q inverse conversion unit 6... PWM type Ifin bar 9 Patent attorney Tsutomu Seitachi Figure 3 Figure 1 Figure 5

Claims (1)

[Scope of Claims] Current supply means for supplying an actual current to an AC rotating machine; current detection means for detecting the actual current supplied by the current supply means; and detecting the rotational position of a rotor of the AC rotating machine. a rotational position detection means for detecting the rotor; and a transformation for converting the actual current detected by the current detection means into a coordinate system determined on the rotor based on the rotational position of the rotor detected by the rotational position detection means. a means for detecting the deviation between the actual current coordinate-converted by the converting means and the target current defined on the coordinate system for a predetermined period of time from the time when the actual current and rotational position are detected by the current detection means and rotational position detection means; Determine the control amount to reduce later,
A control device for an AC motor, comprising: a control means for controlling the current supply means; an estimating means for estimating the amount of change in the rotational position of the rotor during the predetermined time; and an amount of change in the rotational position estimated by the estimating means. and a correction means for correcting the control amount determined by the control means based on the control means for an AC rotating machine.