JP4073302B2 - Control device for synchronous motor - Google Patents

Description

【００１０】
となる。
【００１１】
角度誤差演算器８は、
【００１２】

【００１３】
でｄｑ軸からなる座標軸とγδ軸からなる座標軸との角度差Δθを求める。ここで、Ｌｄは永久磁石型同期電動機１のｄ軸のインダクタンスであり、Ｌｑはｑ軸のインダクタンスである。（２）式が成り立つ理由を以下に説明する。
【００１４】
永久磁石型同期電動機の特性式は、
【００１５】

【００１６】
で表すことができる。ここで、ωは回転子の回転角速度であり、Ｒは巻線抵抗値であり、φは永久磁石が巻線に鎖交する磁束であり、Δθ＝θｒ−θであり、θｒはｄｑ軸の座標軸の回転角度である。（３）式はγδの回転する座標上の式なので電流や電圧の基本波成分は直流となるため、電圧に高周波電圧が重畳されると（３）式の高周波成分のみは、
【００１７】

【００１８】
で近似できる。ここでｖｈγ、ｖｈδ、ｉｈγ、ｉｈδは高周波成分の電圧と電流である。（４）式から電流の微分項を求めると、
【００１９】

【００２０】
となる。電圧の高周波成分は、
【００２１】

【００２２】
と表される。ここで、ｖｍγ、ｖｍδは電圧の定常成分である。（６）式を代入した（５）式を時刻ｔ０からｔ０＋Ｔの間とｔ１からｔ１＋Ｔの間で積分すると
【００２３】

【００２４】
となり、（７）式から（８）式を引いて（１）式を代入すると、
【００２５】

【００２６】
となる。（９）式より、
【００２７】

【００２８】
となり、ｓｉｎ２Δθ＝２Δθと近似すると（２）式が導き出される。
【００２９】
軸推定器９は、角度誤差演算器８の出力の角度差Δθが零となるようにθを調節する。例えば、Δθを比例積分増幅してωを推定し、それを時間積分してθを得る構成とする。そうするとΔθが零に収束するだけでなく回転子の回転角速度ωも得ることができる。
【００３０】
【発明の効果】
本発明により、位置センサを用いることなく同期電動機のトルク制御が可能となり位置センサを用いることによるさまざまな問題点を解決できる。
【図面の簡単な説明】
【図１】本発明の一実施例を表すブロック図である。
【符号の説明】
１・・・永久磁石型同期電動機
２・・・電力変換器
３・・・トルク制御器
４・・・高周波重畳器
５・・・電流電圧変換器
６・・・電流変化量差演算器
７・・・電圧積分差演算器
８・・・角度誤差演算器
９・・・軸推定器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for estimating a rotor position from an input current and a voltage of a synchronous motor without using a position sensor for detecting the rotor position of the synchronous motor in a synchronous motor control device.
[0002]
[Prior art]
For example, in a permanent magnet type synchronous motor having a permanent magnet inside a rotor, assuming two-axis coordinates with the d-axis being the N-pole direction of the permanent magnet and the q-axis being orthogonal thereto, the current of each axis is assumed. Is controlled to control the torque of the permanent magnet type synchronous motor. Therefore, a position sensor that detects the rotation angle of the rotor is necessary to know the direction of the coordinate axes. (For example, refer to Patent Document 1).
[0003]
[Patent Document 1]
JP-A-11-160101 (FIG. 2)
[0004]
[Problems to be solved by the invention]
In the prior art described above, a position sensor is required to detect the rotation angle of the rotor of the synchronous motor when controlling the torque of the synchronous motor. Since the position sensor is a precision device, it is less resistant to various environments than an electric motor. Therefore, by attaching the position sensor, the application range of the electric motor system is limited, the life is shortened, and the cost is increased.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, in the synchronous motor control device of the present invention, two orthogonal axes are assumed on the rotor, and the input current and the input voltage of the synchronous motor are divided into the coordinate components, respectively. Current voltage converting means, high frequency superimposing means for superimposing a high frequency voltage on the input voltage of the synchronous motor, and the time t0 from the amount of change of each current component of the current voltage converting means output from time t0 to a predetermined period T. Is a current change amount difference calculating means for outputting a difference obtained by subtracting a change amount from the time t1 to the predetermined period T, and time integration of each voltage component of the current-voltage conversion means output from the time t0 to the predetermined period T. A voltage integration difference calculation means for outputting a value obtained by subtracting a value obtained by time integration of each voltage component from the time t1 to the predetermined period T, and an output of the current change amount difference calculation means. Angle error calculating means for obtaining an angle difference between the coordinate axis and the salient pole axis of the rotor from the output of the voltage integral difference calculating means, and the angle difference of the output of the angle error calculating means is zero. And an axis estimating means for rotating the coordinates.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention is shown in FIG. 1 and will be described in detail with reference to FIG.
The permanent magnet type synchronous motor 1 is supplied with power from the power converter 2. The power converter 2 outputs voltages according to the input voltage command v2. The torque controller 3 assumes that the input θ matches the angle of the coordinate axis composed of the d axis and the q axis, and the current component of the dq axis of the permanent magnet type synchronous motor 1 is a value corresponding to the torque command τ. A voltage command v1 is output. The high frequency superimposer 4 superimposes the high frequency voltage on the voltage command v1 and outputs it as a new voltage command v2. The superposed voltage may be alternating or rotating, and the waveform is not limited to a sine wave, but may be a rectangular wave or a triangular wave. The current-voltage converter 5 divides the input current i and the input voltage v of the permanent magnet type synchronous motor 1 into components of a coordinate axis composed of orthogonal γ-axis and δ-axis rotated by an angle θ, respectively, and iγ, iδ, Output as vγ and vδ.
[0007]
The current change amount difference calculator 6 outputs Δiγ and Δiδ obtained by subtracting the change amount from the time t1 to T different from the time t0 from the change amount from the time t0 to the predetermined period T of iγ and iδ. For example, iγ and iδ at time t0 are iγ00 and iδ00, respectively, iγ and iδ at time t0 + T are iγ01 and iδ01, iγ and iδ at time t1 are iγ10 and iδ10, respectively, and iγ and iδ at time t1 + T are iγ11, respectively. , Iδ11,
Δiγ = (iγ01−iγ00) − (iγ11−iγ10)
Δiδ = (iδ01−iδ00) − (iδ11−iδ10)
Will be output.
[0008]
The voltage integration difference calculator 7 outputs, as Δvγ and Δvδ, values obtained by subtracting values obtained by time integration from time t1 to t1 + T from values obtained by time integration of vγ and vδ from time t0 to t0 + T. That means
[0009]

[0010]
It becomes.
[0011]
The angle error calculator 8 is
[0012]

[0013]
To obtain the angle difference Δθ between the coordinate axis consisting of the dq axis and the coordinate axis consisting of the γδ axis. Here, Ld is the d-axis inductance of the permanent magnet type synchronous motor 1, and Lq is the q-axis inductance. The reason why the formula (2) holds will be described below.
[0014]
The characteristic equation of the permanent magnet type synchronous motor is
[0015]

[0016]
Can be expressed as Here, ω is the rotational angular velocity of the rotor, R is the winding resistance value, φ is the magnetic flux interlinking the permanent magnet with the winding, Δθ = θr−θ, and θr is the dq axis The rotation angle of the coordinate axis. Since the equation (3) is an equation on the rotating coordinates of γδ, the fundamental wave component of current and voltage is DC, so when a high-frequency voltage is superimposed on the voltage, only the high-frequency component of (3) is
[0017]

[0018]
Can be approximated by Here, vhγ, vhδ, ihγ, ihδ are the voltage and current of the high frequency component. When the differential term of the current is obtained from the equation (4),
[0019]

[0020]
It becomes. The high frequency component of the voltage is
[0021]

[0022]
It is expressed. Here, vmγ and vmδ are steady components of voltage. Integrating equation (5) substituting equation (6) between time t0 and t0 + T and between t1 and t1 + T,

[0024]
When substituting equation (1) by subtracting equation (8) from equation (7),
[0025]

[0026]
It becomes. From equation (9)
[0027]

[0028]
When approximated as sin2Δθ = 2Δθ, equation (2) is derived.
[0029]
The axis estimator 9 adjusts θ so that the angle difference Δθ of the output of the angle error calculator 8 becomes zero. For example, Δθ is proportionally integrated and amplified to estimate ω, and time integration is performed to obtain θ. Then, not only can Δθ converge to zero, but also the rotational angular velocity ω of the rotor can be obtained.
[0030]
【The invention's effect】
According to the present invention, torque control of a synchronous motor can be performed without using a position sensor, and various problems caused by using the position sensor can be solved.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type synchronous motor 2 ... Power converter 3 ... Torque controller 4 ... High frequency superimposer 5 ... Current-voltage converter 6 ... Current change amount difference calculator 7- ..Voltage integral difference calculator 8 ... Angle error calculator 9 ... Axis estimator

Claims (1)

In a control device for driving a synchronous motor having a rotor with magnetic saliency, assuming two orthogonal coordinates on the rotor, the input current and the input voltage of the synchronous motor are divided into the coordinate components, respectively. Current voltage converting means, high frequency superimposing means for superimposing a high frequency voltage on the input voltage of the synchronous motor, and the time t0 from the amount of change of each current component of the current voltage converting means output from time t0 to a predetermined period T. Is a current change amount difference calculating means for outputting a difference obtained by subtracting a change amount from the time t1 to the predetermined period T, and time integration of each voltage component of the current-voltage conversion means output from the time t0 to the predetermined period T. A voltage integral difference calculating means for outputting a value obtained by subtracting a value obtained by time integration of each voltage component from the time t1 to the predetermined period T, and the current change difference calculating means. Angle error calculating means for obtaining an angle difference between the axis of the coordinate and the axis of the salient pole of the rotor from the output of the voltage integral difference calculating means, and the angle difference of the output of the angle error calculating means is zero. A control apparatus for a synchronous motor, comprising: an axis estimating means for rotating the coordinates so that

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