JPH0799779A - Controlling device for self-excited type power conversion device - Google Patents

Abstract

PURPOSE:To execute a high-speed control and also to suppress occurrence of an overcurrent due to a ground fault accident by a method wherein a three-phase AC voltage and a three- phase alternating current are converted into coordinate systems of two axes of alphabeta respectively so as to determine an instantaneous actual power and an instantaneous virtual power, these powers are divided by the amplitude of the AC voltage and thereby the current converted into a two-axes coordinate system of (dq) is determined. CONSTITUTION:A deviation of an output of an operational amplifier 33 which computes and amplifies a deviation of a current command value Iqp of an axis (q) from a current value Iq of an AC system of dq-system coordinates, from an output of a multiplier 34 which multiplies a current value Id by an impedance of a transformer 4, is determined by an adder 35. Besides, an output of an operational amplifier 37 which computes and amplifies a deviation of a current command value Idp of an axis (d) from the current value Id of the AC system of the dq-system coordinates, an output of a multiplier 38 which multiplies the current value Iq by the impedance of the transformer 4 and a bias signal V0 are added up by an adder 39. Outputs of these adders 35 and 39 are converted inversely into an alphabeta coordinate system by a converter 40 and further transformed into three-phase values by a conversion circuit 41, and a switching element of a power conversion device 5 is controlled by a PWM circuit 42.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、特に過電流の抑制を高
速に行なう自励式電力変換器の制御装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a self-excited power converter which suppresses overcurrent at high speed.

【０００２】[0002]

【従来の技術】自己消弧機能を持ったスイッチング素子
で構成される自励式電力変換器は、等価的に電圧源と見
做すことができるので、その設置点近傍の交流系統で事
故が発生すると、自励式電力変換器から過電流が流れ、
該変換器を構成する通電要素を破壊するおそれがあり、
過電流抑制のために高速の制御が必要となる。2. Description of the Related Art A self-excited power converter composed of a switching element having a self-extinguishing function can be regarded equivalently as a voltage source, so that an accident occurs in an AC system near its installation point. Then, an overcurrent flows from the self-excited power converter,
There is a risk of destroying the energizing elements that make up the converter,
High-speed control is required to suppress overcurrent.

【０００３】ところで自励式電力変換器は電流を流し始
める時点と切る時点を任意に制御することができ、これ
によって２つの状態量、即ち自励式電力変換器の直流電
圧と無効電力、または有効電力と無効電力を制御するこ
とができる。この場合は、例えば直流電圧制御系と無効
電力制御系を設けて、制御系の出力に応じて自励式電力
変換器の交流出力電圧を制御することになる。しかし、
直流電圧制御系と無効電力制御系の２つの量が互いに干
渉して高速の制御が行えない問題がある。By the way, the self-excited power converter can arbitrarily control the time point when the current starts to flow and the time point when the current is cut off, whereby two state quantities, that is, the DC voltage and the reactive power or the active power of the self-excited power converter are controlled. And the reactive power can be controlled. In this case, for example, a DC voltage control system and a reactive power control system are provided, and the AC output voltage of the self-excited power converter is controlled according to the output of the control system. But,
There is a problem that two quantities of the DC voltage control system and the reactive power control system interfere with each other and high-speed control cannot be performed.

【０００４】また、一般に交流系統での事故の大半は一
線地絡で、この場合に過電流を抑制するためには、一線
地絡による系統の不平衡電圧に応じて自励式変換器でも
不平衡電圧を発生させる必要がある。不平衡電圧を発生
させるためには自励式変換器で構成されるインバータを
３相個別に制御しなければならない。In general, most of the accidents in the AC system are one-line ground faults. In this case, in order to suppress the overcurrent, even the self-excited converter is unbalanced according to the unbalanced voltage of the system due to the one-line ground fault. It is necessary to generate a voltage. In order to generate an unbalanced voltage, it is necessary to individually control the inverters composed of self-excited converters in three phases.

【０００５】[0005]

【発明が解決しようとする課題】制御系の応答を早くす
るために、直流電圧と無効電力といった２つの量を各々
直角方向のベクトル量として扱い、各々独立に高速制御
する方法が開発されている。しかし２つの量を直角方向
のベクトル量として扱うためには、例えば文献Y.Tokiw
a, et al.,"Application of a digital instantaneous
currnet controlfor static induction thyristor conv
erters in the utility line", PCIM'88PROCEEDINGS(p3
43〜p351) （1988年発行）に見られるように、ベクトル
量に変換するために交流系統の電圧位相角θを検出する
必要がある。また、２軸に分けられ制御された量を３相
個別制御するために３相に変換するためには交流系統の
電圧位相θを用いて変換する必要がある。In order to speed up the response of the control system, a method has been developed in which two quantities such as DC voltage and reactive power are treated as vector quantities in the direction perpendicular to each other and each is independently controlled at high speed. . However, in order to treat the two quantities as vector quantities in the orthogonal direction, for example, the document Y. Tokiw
a, et al., "Application of a digital instantaneous
currnet controlfor static induction thyristor conv
erters in the utility line ", PCIM'88PROCEEDINGS (p3
43-p351) (published in 1988), it is necessary to detect the voltage phase angle θ of the AC system in order to convert it into a vector quantity. Further, in order to convert the controlled amount divided into two axes into three phases for individual control of three phases, it is necessary to perform conversion using the voltage phase θ of the AC system.

【０００６】本発明の目的は、系統の電圧位相角θを簡
単な方法で検出し、これを用いて高速制御の行える自励
式電力変換器の制御装置を提供し、同時に地絡事故によ
る過電流発生を抑制することのできる自励式電力変換器
の制御装置を提供することである。An object of the present invention is to provide a control device for a self-excited power converter capable of detecting a voltage phase angle θ of a grid by a simple method and performing high speed control using the same, and at the same time, providing an overcurrent due to a ground fault. It is an object of the present invention to provide a control device for a self-excited power converter that can suppress the generation.

【０００７】[0007]

【課題を解決するための手段】上記目的を達成するため
に、変換用変圧器を介して交流系統に接続される自励式
電力変換器が、前記交流系統の電圧位相のｃｏｓ値及び
ｓｉｎ値を用いてベクトル制御され、前記交流系統の３
相交流電圧と３相交流電流を検出しこれらをαβの直交
する２軸座標系成分に変換するαβ変換手段と、該αβ
変換された出力を電圧位相のｃｏｓ値及びｓｉｎ値を用
いてｄｑの直交する２軸座標系に変換するｄｑ変換手段
と、前記ｄｑ変換された出力とｄｑ軸座標系の前記自励
式電力変換器の指令値との偏差を求める偏差検出手段
と、該偏差検出手段出力と前記変換用変圧器リアクタン
ス電圧降下分を補正してｄｑ軸座標系指令値を発する指
令値発生手段と、該指令値発生手段出力をｄｑへ逆変換
するｄｑ逆変換手段と、該ｄｑ逆変換手段出力を３相へ
変換するαβ逆変換手段と、該αβ逆変換手段出力によ
りパルス幅変調制御信号を作成する信号発生手段を含ん
でなる自励式電力変換器の制御装置において、前記電圧
位相のｃｏｓ値及びｓｉｎ値の検出手段が、前記交流系
統の３相交流電圧と３相交流電流を検出しαβの直交す
る２軸座標系成分に変換するαβ変換手段と、該αβ変
換手段により変換された信号から実電力及び虚電力を計
算する電力計算手段と、前記交流電圧の大きさを検出す
る電圧絶対値検出手段と、前記電力計算手段の出力をそ
れぞれ前記電圧絶対値検出手段の出力で除算してｄｑ座
標系の電流信号に変換する電流変換手段と、前記αβ変
換手段により変換された交流電流出力及び前記ｄｑ座標
系の電流信号に変換された信号から前記電圧位相のｃｏ
ｓ値及びｓｉｎ値を計算するｃｏ−ｓｉ算出手段とを備
えている。In order to achieve the above object, a self-excited power converter connected to an AC system via a conversion transformer converts a cos value and a sin value of a voltage phase of the AC system. Vector control using 3 of the AC system
Αβ conversion means for detecting a phase AC voltage and a three-phase AC current and converting them into a component of a two-axis coordinate system of αβ orthogonal to each other, and the αβ
Dq conversion means for converting the converted output into a two-axis coordinate system of orthogonal dq using the cos value and sin value of the voltage phase; and the self-excited power converter of the dq converted output and the dq axis coordinate system. Deviation detecting means for obtaining a deviation from the command value, command value generating means for correcting the output of the deviation detecting means and the conversion transformer reactance voltage drop, and issuing a command value for the dq axis coordinate system, and the command value generating means. Dq inverse conversion means for inversely converting the output of the means into dq, αβ inverse conversion means for converting the output of the dq inverse conversion means into three phases, and signal generation means for producing a pulse width modulation control signal by the output of the αβ inverse conversion means. In a control device for a self-excited power converter including: a detecting means for detecting a cos value and a sin value of the voltage phase detects a three-phase alternating voltage and a three-phase alternating current of the alternating current system, and has two axes of αβ orthogonal to each other. Convert to coordinate system component Of αβ conversion means, power calculation means for calculating real power and imaginary power from the signal converted by the αβ conversion means, voltage absolute value detection means for detecting the magnitude of the AC voltage, and power calculation means of the power calculation means. Current converting means for dividing the output by the output of the absolute voltage value detecting means to convert it into a current signal of the dq coordinate system, and an AC current output converted by the αβ converting means and a current signal of the dq coordinate system. From the received signal, the voltage phase co
and a co-si calculating means for calculating the s value and the sin value.

【０００８】また前記αβ変換手段によりαβ変換され
た交流電圧出力を、前記ｃｏ−ｓｉ算出手段の出力を用
いてｄｑ座標系の電圧へ変換する電圧変換手段と、該電
圧変換手段の出力を前記指令値発生手段へ加算する手段
を備えることが望ましい。[0008] Further, the AC voltage output αβ converted by the αβ conversion means is converted into a voltage of the dq coordinate system by using the output of the co-si calculation means, and the output of the voltage conversion means is It is desirable to provide means for adding to the command value generating means.

【０００９】[0009]

【作用】このように構成することにより、本発明によれ
ば次の作用により上記の目的が達成される。本発明によ
れば、電圧位相角のｓｉｎθ、ｃｏｓθ値を求められ
る。With this structure, the above-mentioned object can be achieved by the present invention by the following operations. According to the present invention, the sin θ and cos θ values of the voltage phase angle can be obtained.

【００１０】まず、自励式電力変換器出力の３相交流電
圧及び電流を各αβの２軸の座標系へ変換する。この座
標系の電圧・電流から、瞬時実電力と瞬時虚電力が求め
られる。そして瞬時実電力と瞬時虚電力を交流電圧の大
きさで除算するとｄｑの２軸座標系へ変換された電流が
求められる。一方、この電流は前記のαβの座標系と前
記の位相角θのｓｉｎθとｃｏｓθで変換される関係に
あるので、ｓｉｎθ、ｃｏｓθはαβの座標系及びｄｑ
座標系の電流を用いて求められる。First, the three-phase AC voltage and current output from the self-excited power converter are converted into a two-axis coordinate system for each αβ. From the voltage / current of this coordinate system, the instantaneous real power and the instantaneous imaginary power can be obtained. Then, the instantaneous real power and the instantaneous imaginary power are divided by the magnitude of the alternating voltage to obtain the current converted into the dq two-axis coordinate system. On the other hand, this current is in a relationship of being converted by sin θ and cos θ of the phase angle θ with the α β coordinate system, so sin θ and cos θ are the α β coordinate system and dq.
It is calculated using the current in the coordinate system.

【００１１】このｓｉｎθ、ｃｏｓθを用いることによ
り、３相電流をαβの座標系を介してｄｑ座標系のｄ軸
成分とｑ軸成分に変換できる。この直交するｄ軸成分と
ｑ軸成分は、系統電圧に不平衡分がなければ、相互に干
渉することなく単独に制御されるので、制御指令に対し
て指令の実行が高速に可能である。例えばこの２成分
を、それぞれ直流電圧と無効電力に対応付けることによ
って相互に非干渉の高速応答の制御装置が実現できる。By using sin θ and cos θ, the three-phase current can be converted into the d-axis component and the q-axis component of the dq coordinate system via the αβ coordinate system. If there is no unbalanced component in the system voltage, the orthogonal d-axis component and q-axis component are independently controlled without interfering with each other, and therefore the command can be executed at high speed. For example, by associating the two components with the DC voltage and the reactive power, respectively, it is possible to realize a control device having a non-interfering high-speed response.

【００１２】また、電圧変換手段の出力を、上記のｄｑ
軸の指令値発生手段へ加算することにより、インバータ
で不平衡電圧を含んだ電圧を発生することができる。地
絡事故時の電源電圧に発生する不平衡電圧に合わせて、
インバータで不平衡電圧を発生すれば、インバータから
系統へ不平衡電流は流れない。Further, the output of the voltage converting means is set to the above dq.
By adding to the command value generating means of the axis, the inverter can generate a voltage including an unbalanced voltage. In accordance with the unbalanced voltage generated in the power supply voltage at the time of a ground fault,
If an unbalanced voltage is generated in the inverter, no unbalanced current will flow from the inverter to the grid.

【００１３】[0013]

【実施例】以下、本発明の一実施例を図１に示す。本図
は電圧位相角θに関係した信号を使った制御回路をもつ
自励式電力変換器を用いた静止形無効電力補償装置の制
御装置のブロック図である。交流電源１はインピ−ダン
スを有する送電線２を経て負荷３に電力を供給する。静
止形無効電力補償装置の構成は、自己消弧機能を持った
ＧＴＯ等のスイッチング素子とこれに逆並列に接続され
たダイオ−ドでア−ムが構成され、３相ブリッジ結線回
路で構成させる、電圧型の自励式インバ−タ５、インバ
−タ電流の変化率を制限する直流リアクトル６、インバ
−タ直流側のコンデンサ７、及びインバ−タ５を系統と
連系する変換用変圧器４とからなっている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention is shown in FIG. This figure is a block diagram of a controller of a static var compensator using a self-excited power converter having a control circuit using a signal related to the voltage phase angle θ. The AC power supply 1 supplies electric power to the load 3 via the power transmission line 2 having impedance. The static var compensator is composed of a switching element such as a GTO having a self-extinguishing function and a diode connected in antiparallel with the switching element to form an arm with a three-phase bridge connection circuit. , A voltage type self-exciting inverter 5, a DC reactor 6 for limiting the rate of change of the inverter current, a capacitor 7 on the DC side of the inverter, and a conversion transformer 4 for connecting the inverter 5 to the grid. It consists of

【００１４】この静止形無効電力補償装置の制御装置の
構成は次のとおりである。交流側３相電流を検出する交
流電流検出器５０から第３の変換回路３０へ入力され、
数式１に従って３相交流電流をαβの２相座標系のＩ
α、Ｉβに変換される。The configuration of the control device of this static var compensator is as follows. An AC current detector 50 that detects an AC side three-phase current is input to the third conversion circuit 30,
According to Equation 1, the three-phase alternating current is I in the two-phase coordinate system of αβ.
Converted to α and Iβ.

【００１５】[0015]

【数１】 [Equation 1]

【００１６】Ｉα、Ｉβは第４の変換回路３１へ入力さ
れ、図２で求められる変換係数ｃｏとｓｉを使用し数式
２に従って、ｄｑの２軸座標系の値Ｉｑ、Ｉｄに変換さ
れる。Iα and Iβ are input to the fourth conversion circuit 31, and are converted into the values Iq and Id of the two-axis coordinate system of dq according to Formula 2 using the conversion coefficients co and si obtained in FIG.

【００１７】[0017]

【数２】 [Equation 2]

【００１８】ここで交流電流の位相角をθ＝２πｆｔと
置く。Here, the phase angle of the alternating current is set as θ = 2πft.

【００１９】一方、自励式変換器の交流側出力の交流電
圧をＶｕ、Ｖｖ、Ｖｗとすると数式１の場合と同様に数
式３から３相交流をαβの２相へ変換した信号Ｖα、Ｖ
βが求められる。On the other hand, assuming that the AC voltage of the AC side output of the self-exciting converter is Vu, Vv, Vw, the signals Vα, V obtained by converting the three-phase AC into the two phases αβ in the same manner as in the case of the formula (1).
β is required.

【００２０】[0020]

【数３】 [Equation 3]

【００２１】ここで、静止形無効電力補償装置の制御装
置の構成の説明に先立ち、図２により、位相角θを含む
変換係数ｃｏとｓｉを求めるブロック図を説明する。交
流系統から検出された３相の電流Ｉｕ，Ｉｖ，Ｉｗは第
１の変換回路２１により数式１に従ってα、βの座標系
に変換されＩα、Ｉβを得る。交流系統から検出された
３相交流電圧Ｖｕ，Ｖｖ，Ｖｗも同様に第２の変換回路
２２によりαβの２相に変換される。Prior to the description of the configuration of the controller of the static var compensator, a block diagram for obtaining the conversion coefficients co and si including the phase angle θ will be described with reference to FIG. The three-phase currents Iu, Iv, and Iw detected from the AC system are converted into a coordinate system of α and β by the first conversion circuit 21 according to Formula 1 to obtain Iα and Iβ. Similarly, the three-phase AC voltages Vu, Vv, Vw detected from the AC system are also converted into two phases of αβ by the second conversion circuit 22.

【００２２】前記の変換されたαβ座標系信号は第１の
演算回路２４へ入力され数式４に従って瞬時実電力Ｗｄ
と瞬時虚電力Ｗｑが計算される。（参考文献：赤木他３
名、”瞬時無効電力の一般化理論とその応用”、電気学
会論文誌Ｂ分冊、論文５８−Ｂ６０、昭５８年７月）The converted αβ coordinate system signal is input to the first arithmetic circuit 24 and the instantaneous actual power Wd is calculated according to the equation (4).
And the instantaneous imaginary power Wq is calculated. (Reference: Akagi et al. 3
Name, "Generalized Theory of Instantaneous Reactive Power and Its Application", The Institute of Electrical Engineers of Japan, Volume B, Paper 58-B60, July 1983)

【００２３】[0023]

【数４】Ｗｄ＝Ｖα・Ｉα＋Ｖβ・Ｉβ Ｗｑ＝Ｖα・Ｉβ−Ｖβ・Ｉα ここで交流系統から検出された３相の交流電圧は絶対値
検出回路２３へ入力され交流電圧の大きさＶｏを検出す
る。## EQU00004 ## Wd = V.alpha..multidot.I.alpha. + V.beta..multidot.I.beta. Wq = V.alpha..multidot.I.beta.-V.beta..multidot.Iα The three-phase AC voltage detected from the AC system is input to the absolute value detection circuit 23 to detect the magnitude Vo of the AC voltage. To do.

【００２４】ここで、絶対値検出回路２３は３相交流電
圧Ｖｕ，Ｖｖ，Ｖｗを入力として各相の絶対値のうちの
最大値を取るもので、この検出値は系統電圧のピーク値
相当の値となる。Ｖ₀として実効値が必要な場合は、絶
対値検出回路２３の出力に係数（１／√２）を掛けるこ
とによって簡単に得ることができる。交流電圧の大きさ
Ｖ₀を実効値で扱うかピーク値で扱うかは、後述する数
式８をどちらで表すかによる。Here, the absolute value detection circuit 23 receives the three-phase AC voltages Vu, Vv, Vw and takes the maximum value of the absolute values of the respective phases, and this detected value corresponds to the peak value of the system voltage. It becomes a value. When an effective value is required as V ₀ , it can be easily obtained by multiplying the output of the absolute value detection circuit 23 by a coefficient (1 / √2). Whether the magnitude V ₀ of the AC voltage is treated as an effective value or a peak value depends on which of the following Equation 8 is expressed.

【００２５】第１の演算回路２４で求められた瞬時実電
力Ｗｄと瞬時虚電力Ｗｑは各々数式５の計算を行う回路
２６と２７にて、前記絶対値検出回路２３で検出された
交流電圧の大きさＶｏで除算されＩｄ，Ｉｑが求められ
る。The instantaneous actual electric power Wd and the instantaneous imaginary electric power Wq obtained by the first arithmetic circuit 24 are calculated by the circuits 26 and 27 for calculating the equation 5, respectively, of the AC voltage detected by the absolute value detecting circuit 23. It is divided by the size Vo to obtain Id and Iq.

【００２６】[0026]

【数５】Ｉｄ＝Ｗｄ／Ｖｏ Ｉｑ＝Ｗｑ／Ｖｏ 求められたＩα、Ｉβ、Ｉｄ、Ｉｑは第２の演算回路２
５へ入力され、数式６に従って、ｃｏ＝ｃｏｓθとｓｉ
＝ｓｉｎθが求められる。## EQU5 ## Id = Wd / Vo Iq = Wq / Vo The obtained Iα, Iβ, Id, and Iq are the second arithmetic circuit 2
5, and co = cos θ and si according to Equation 6
= Sin θ is obtained.

【００２７】[0027]

【数６】 [Equation 6]

【００２８】このように電圧と電流からθが求められ
る。この回路によりαβ座標系からｄｑ座標系に変換ま
たはｄｑ座標系からαβ座標系に変換する行列の係数が
求められる。ここでｄｑ座標系からαβ座標系に変換す
る行列の係数は、数式２の変換行列の逆行列を求めれば
良く次式で与えられる。In this way, θ can be obtained from the voltage and the current. With this circuit, the coefficient of the matrix for converting from the αβ coordinate system to the dq coordinate system or from the dq coordinate system to the αβ coordinate system is obtained. Here, the coefficient of the matrix for converting from the dq coordinate system to the αβ coordinate system can be given by the following equation if the inverse matrix of the conversion matrix of Expression 2 is obtained.

【００２９】[0029]

【数７】 [Equation 7]

【００３０】図１に戻り、ｑ軸の電流指令値Ｉｑｐと第
４の変換回路３１によって変換された電流値Ｉｑとの偏
差が第１の加算器３２により求められ、この偏差を演算
増幅回路３３で演算増幅する。上記第４の変換回路３１
によって変換された電流値Ｉｄに前記変換用変圧器４の
インピ−ダンスを掛算器３４で乗じ、演算増幅回路３３
の出力と掛算器３４の出力の偏差が第２の加算器３５で
求められる。ｄ軸の電流指令値Ｉｄｐと上記第４の変換
回路３１によって変換された電流値Ｉｄとの偏差が第３
の加算器３６により求められ、この偏差を演算増幅回路
３７で演算増幅する。上記第４の変換回路３１によって
変換された電流値Ｉｑに前記変換用変圧器４のインピ−
ダンスを掛算器３８で乗じ、演算増幅回路３７の出力と
掛算器３８の出力とバイアス信号Ｖｏを図示の符号で第
４の加算器３９で加算する。加算器３９と加算器３５の
出力は、第５の変換回路４０へ入力され数式７の行列を
使ってｄｑ座標系からαβ座標系に逆変換される。αβ
座標系に変換されたαβ２軸信号は第６の変換回路４１
で３相に変換され、その３相変換された信号に応じてス
イッチング素子をオンオフする制御パルスがパルス幅変
調制御信号作成回路（以降、ＰＷＭ回路と記載する）４
２で作成される。Returning to FIG. 1, the deviation between the q-axis current command value Iqp and the current value Iq converted by the fourth conversion circuit 31 is obtained by the first adder 32, and this deviation is calculated by the operational amplifier circuit 33. Operation is amplified with. The fourth conversion circuit 31
The current value Id converted by the above is multiplied by the impedance of the conversion transformer 4 in a multiplier 34 to obtain an operational amplifier circuit 33.
The difference between the output of 1 and the output of the multiplier 34 is obtained by the second adder 35. The deviation between the d-axis current command value Idp and the current value Id converted by the fourth conversion circuit 31 is the third.
Is calculated by the adder 36, and this difference is arithmetically amplified by the operational amplifier circuit 37. The current value Iq converted by the fourth conversion circuit 31 is converted into the impedance of the conversion transformer 4.
The dance is multiplied by the multiplier 38, and the output of the operational amplifier circuit 37, the output of the multiplier 38 and the bias signal Vo are added by the fourth adder 39 with the sign shown. The outputs of the adder 39 and the adder 35 are input to the fifth conversion circuit 40 and are inversely converted from the dq coordinate system to the αβ coordinate system using the matrix of Expression 7. αβ
The αβ2-axis signal converted into the coordinate system is the sixth conversion circuit 41.
The pulse width modulation control signal generation circuit (hereinafter referred to as a PWM circuit) 4 is converted into three phases by the control pulse for turning on / off the switching element according to the three-phase converted signal.
Created in 2.

【００３１】このＰＷＭ回路５１２の動作を図３を用い
て説明する。図３は１相分の動作波形を示し、（ａ）は
搬送波Ｃと変調波Ｍを示し、（ｂ）はスイッチング素子
の制御パルスであり、搬送波Ｃ＜変調波Ｍのとき「１」
となり、Ｃ＞Ｍのとき「０」となる。「１」のとき３相
ブリッジ結線の上側のスイッチング素子をオンし下側の
スイッチング素子をオフ、「０」のときは上側のスイッ
チング素子をオフし下側のスイッチング素子をオンす
る。この動作により変調波に相似な出力電圧を作り出す
ことができる。The operation of the PWM circuit 512 will be described with reference to FIG. FIG. 3 shows an operation waveform for one phase, (a) shows a carrier wave C and a modulated wave M, (b) is a control pulse of a switching element, and “1” when the carrier wave C <the modulated wave M.
When C> M, it becomes “0”. When it is "1", the upper switching element of the three-phase bridge connection is turned on and the lower switching element is turned off. When it is "0", the upper switching element is turned off and the lower switching element is turned on. By this operation, an output voltage similar to the modulated wave can be created.

【００３２】次に制御装置の動作を図４の電圧・電流の
ベクトル図を用いて説明する。図は無効電力補償装置に
遅れの電流が流れた場合を示す。Ｖｉは無効電力補償装
置のインバ−タの出力電圧、Ｉは電流、Ｘは変換用変圧
器４のリアクタンス、Ｖｏは前述した交流系統の電圧で
ある。ｄ軸を系統電圧Ｖｏと同じ方向にとり、ｑ軸をそ
れより９０度遅れの方向にとる。ｄ−ｑ軸表現によりイ
ンバ−タ電圧Ｖｉのｄ軸成分Ｖｉｄとｑ軸成分Ｖｉｑと
は次式で表される。Next, the operation of the controller will be described with reference to the voltage / current vector diagram of FIG. The figure shows the case where a delayed current flows through the reactive power compensator. Vi is the output voltage of the inverter of the reactive power compensator, I is the current, X is the reactance of the conversion transformer 4, and Vo is the voltage of the AC system described above. The d axis is set in the same direction as the system voltage Vo, and the q axis is set in a direction delayed by 90 degrees. The d-axis component Vid and the q-axis component Viq of the inverter voltage Vi are expressed by the following equations by the d-q axis representation.

【００３３】[0033]

【数８】Ｖｉｄ＝Ｖｏ−Ｘ・Ｉｑ Ｖｉｑ＝Ｘ・Ｉｄ 上式のｑ軸成分は図１の制御装置１０の上部、ｄ軸成分
は下部で制御され、各々の成分は第６の変換回路４１に
よって合成されてインバ−タ出力電圧の指令値としてＰ
ＷＭ回路４２への入力となる。数式８からわかるように
インバ−タ電圧のｄ軸成分は電流のｑ軸成分のみによっ
て制御され、ｑ軸成分はｄ軸成分のみによって制御さ
れ、お互いの電流成分の干渉はない。ｄ軸、ｑ軸を各々
直流電圧(または有効電力)と無効電力に対応させること
により、２つの状態を非干渉に制御できる。従って制御
応答を早くできる。## EQU00008 ## Vid = Vo-X.Iq Viq = X.Id The q-axis component of the above equation is controlled by the upper part of the controller 10 of FIG. 1, the d-axis component is controlled by the lower part, and each component is the sixth conversion circuit. 41 as a command value of the inverter output voltage P
It is an input to the WM circuit 42. As can be seen from the equation (8), the d-axis component of the inverter voltage is controlled only by the q-axis component of the current, the q-axis component is controlled only by the d-axis component, and there is no interference between the current components. By making the d-axis and the q-axis correspond to the DC voltage (or the active power) and the reactive power, respectively, the two states can be controlled without interference. Therefore, the control response can be speeded up.

【００３４】図４のベクトル図に示すように、系統電圧
Ｖ₀はｄ軸成分のみでｑ軸成分はない。即ち不平衡電圧
は含まれていない。不平衡電圧が全く含まれない、また
は含まれてもその量が小さい場合は図１の実施例で何ら
問題なく安定に運転できる。本発明の制御装置を自励式
電力変換器で構成される直流送電に適用した場合の実施
例を図５に示す。交流系統１１と１２は変換用変圧器１
４、１５を介して、自励式電力変換器５１、５２で構成
される順変換器、または逆変換器に接続される。直流リ
アクトルの図示は省略している。制御装置２０は電流の
指令値を除いて順変換器も逆変換器も同様であるので、
自励式電力変換器５１の場合について記載している。こ
こで、制御装置１０の構成は図１と同一である。電流指
令値ＩｑｐとＩｄｐに適切な値を与えることにより、上
述の無効電力制御装置同様に高速制御の行える自励式電
力変換器を備えた直流送電の制御装置が得られる。As shown in the vector diagram of FIG. 4, the system voltage V ₀ has only a d-axis component and no q-axis component. That is, the unbalanced voltage is not included. If the unbalanced voltage is not included at all or if the amount is small, stable operation can be performed without any problem in the embodiment of FIG. FIG. 5 shows an embodiment in the case where the control device of the present invention is applied to DC power transmission including a self-excited power converter. AC systems 11 and 12 are conversion transformers 1
Via 4 and 15, it is connected to a forward converter or an inverse converter composed of self-excited power converters 51 and 52. Illustration of the DC reactor is omitted. Since the control device 20 is the same for the forward converter and the inverse converter except for the command value of the current,
The case of the self-excited power converter 51 is described. Here, the configuration of the control device 10 is the same as that in FIG. By giving appropriate values to the current command values Iqp and Idp, it is possible to obtain a DC power transmission control device including a self-excited power converter that can perform high-speed control similarly to the reactive power control device described above.

【００３５】次に、図６に、上述の無効電力制御装置を
用いて系統に不平衡電圧を発生させることにより地絡事
故電流を流さない運転を可能とした自励式電力変換器の
制御装置の実施例を示す。系統電圧の不平衡成分が無視
できない場合は図２の場合とは異なって図６に示す制御
装置３０が必要となる。系統電圧Ｖ₀に不平衡電圧成分
が含まれると、図４に示すＶ₀にｄ軸成分の他にｑ軸成
分が現れる。図４から類推がつくように、この場合は２
軸の成分に分けて系統電圧を検出し、数式９に従ってイ
ンバータを制御することにより、インバータで不平衡電
圧を含んだＶ₀を発生させることができる。Next, FIG. 6 shows a controller for a self-excited power converter that enables an operation without causing a ground fault accident current by generating an unbalanced voltage in the system using the above-mentioned reactive power controller. An example is shown. When the unbalanced component of the system voltage cannot be ignored, unlike the case of FIG. 2, the control device 30 shown in FIG. 6 is required. When the system voltage V ₀ includes an unbalanced voltage component, a q-axis component appears in V ₀ shown in FIG. 4 in addition to the d-axis component. As can be inferred from FIG. 4, in this case 2
By detecting the system voltage separately for the components of the axis and controlling the inverter according to Formula 9, the inverter can generate V _{0 including the} unbalanced voltage.

【００３６】[0036]

【数９】Ｖｉｄ＝Ｖｄ−Ｘ・Ｉｑ Ｖｉｑ＝Ｖｑ＋Ｘ・Ｉｄ ここで、不平衡電圧を発生することにより、地絡などに
よる過電流の発生を抑制できる原理を説明する。系統の
Ｕ相電圧をＶｕ＝（Ｖ₁＋Ｖ₂）と表す。ここに、Ｖ₁は
正相電圧、Ｖ₂は不平衡電圧である。ここでインバータ
の出力電圧をＶｕ’＝（Ｖ₁’＋Ｖ₂’）と表すと、イン
バータから流れるｕ相電流ｉｕは、ｕ相回路のインピー
ダンスをＸｕとすると、ｉｕ＝｛（Ｖ₁’＋Ｖ₂’）−
（Ｖ₁＋Ｖ₂）｝／Ｘｕとなる。[Formula 9] Vid = Vd−X · Iq Viq = Vq + X · Id Here, a principle that an overcurrent due to a ground fault or the like can be suppressed by generating an unbalanced voltage will be described. The U-phase voltage of the system is represented by Vu = (V ₁ + V ₂ ). Here, V ₁ is a positive phase voltage and V ₂ is an unbalanced voltage. When the output voltage of the inverter is expressed as Vu ′ = (V ₁ '+ V ₂ '), the u-phase current iu flowing from the inverter is iu = {(V ₁ '+ V ₂₎ , where Xu is the impedance of the u-phase circuit. ')-
(V ₁ + V ₂ )} / Xu.

【００３７】Ｖ₂’＝Ｖ₂のときは不平衡電流は流れない
が、Ｖ₂’≠Ｖ₂のときはｉ₂＝（Ｖ₂’−Ｖ₂）／Ｘｕ
の不平衡電流が流れる。ちなみに、ｉ₁＝（Ｖ₁’−
Ｖ₁）／Ｘｕ は平衡電流を表す。An unbalanced current does not flow when V ₂ ′ = V ₂ , but i ₂ = (V ₂ ′ −V ₂ ) / Xu when V ₂ ′ ≠ V _2.
Unbalanced current flows. By the way, i ₁ = (V ₁ '−
V ₁ ) / Xu represents a balanced current.

【００３８】制御装置１０は図１と同じ符号のものは同
じ機能を表すので、新しい制御装置４５についてのみ説
明すると、交流系統の３相交流電圧を電圧検出器５３に
より検出し、３相電圧を数式３に従って第７の変換回路
４３によりαβ座標系に変換する。図２で求めた変換係
数ｃｏとｓｉを用いて第８の変換回路４４によりαβ座
標系からｄｑ座標系に変換する。ここで求められた信号
Ｖｄ及びＶｑは各々前記第２の加算器３５及び第４の加
算器３９に導かれ、数式９にしたがってインバ−タ電圧
のｄ軸成分Ｖｉｄ及びｑ軸成分Ｖｉｑの演算に使われ
る。Since the control device 10 having the same reference numerals as those in FIG. 1 has the same function, only the new control device 45 will be described. The three-phase AC voltage of the AC system is detected by the voltage detector 53 and the three-phase voltage is detected. The seventh conversion circuit 43 converts into the αβ coordinate system according to Expression 3. Using the conversion coefficients co and si obtained in FIG. 2, the eighth conversion circuit 44 converts the αβ coordinate system to the dq coordinate system. The signals Vd and Vq obtained here are led to the second adder 35 and the fourth adder 39, respectively, and are used to calculate the d-axis component Vid and the q-axis component Viq of the inverter voltage according to equation (9). used.

【００３９】図１の場合には系統の電圧は不平衡電圧を
含まないｄ軸成分のみとしたが、図６では交流電圧をｄ
軸成分とｑ軸成分に分けてインバ−タ電圧を制御するの
で不平衡電圧を発生させることができる。したがって、
上述したように、系統に地絡事故などによる不平衡電圧
が含まれていても、インバ−タも同様に不平衡電圧を発
生させることができるので、インバ−タから不平衡電流
を系統に流すことはなく、これによる過電流は抑制され
る。In the case of FIG. 1, the system voltage is the d-axis component that does not include the unbalanced voltage, but in FIG.
Since the inverter voltage is controlled separately for the axial component and the q-axis component, an unbalanced voltage can be generated. Therefore,
As described above, even if the system includes an unbalanced voltage due to a ground fault, the inverter can also generate the unbalanced voltage, so that an unbalanced current flows from the inverter to the system. In this case, overcurrent due to this is suppressed.

【００４０】以上の制御装置では図２で求めた変換係数
を使ってαβ座標系からｄｑ座標系へ電流・電圧を変換
する、または新たに３相からαβ座標系の２相に変換す
る場合について示したが、図１中にαβ座標系に変換し
た値Ｉα、Ｉβ、Ｖα、Ｖβ及び、電流をｄｑ座標系に
変換した値Ｉｄ、Ｉｑは求められているので、これをそ
のまま使った方が計算が少なくてすみ簡単となる。In the above control device, the current / voltage is converted from the αβ coordinate system to the dq coordinate system using the conversion coefficient obtained in FIG. 2, or a new phase is converted to two phases of the αβ coordinate system. As shown in FIG. 1, the values Iα, Iβ, Vα, Vβ converted into the αβ coordinate system and the values Id, Iq converted with the current in the dq coordinate system are obtained in FIG. 1, so it is better to use them as they are. Less calculation and easier.

【００４１】[0041]

【発明の効果】本発明によれば、系統の電圧位相を直接
検出することなく高速制御及び不平衡電圧発生の可能な
自励式電力変換器が得られる。系統事故により不平衡電
圧が発生しても自励式電力変換器で不平衡電圧を発生す
ることができるので、変換器に不平衡電流は流れない。
その結果、地絡事故などによる過電流の発生を抑制する
効果が発生する。According to the present invention, a self-excited power converter capable of high-speed control and generation of an unbalanced voltage can be obtained without directly detecting the voltage phase of the system. Even if an unbalanced voltage is generated due to a system fault, the unbalanced voltage can be generated by the self-excited power converter, so that no unbalanced current flows through the converter.
As a result, the effect of suppressing the occurrence of overcurrent due to a ground fault or the like occurs.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の一実施例の自励式電力変換器の制御装
置のブロック図である。FIG. 1 is a block diagram of a control device for a self-excited power converter according to an embodiment of the present invention.

【図２】変換係数を求める回路の一実施例を示すブロッ
ク図である。FIG. 2 is a block diagram showing an embodiment of a circuit for obtaining a conversion coefficient.

【図３】パルス幅変調制御の波形作成回路の動作を説明
する図である。FIG. 3 is a diagram illustrating an operation of a waveform creating circuit for pulse width modulation control.

【図４】本発明の一実施例における電圧・電流のベクト
ル図である。FIG. 4 is a vector diagram of voltage / current in one embodiment of the present invention.

【図５】本発明の他の実施例を示すブロック図である。FIG. 5 is a block diagram showing another embodiment of the present invention.

【図６】本発明の第３の実施例を示す無効電力補償装置
の制御装置のブロック図である。FIG. 6 is a block diagram of a control device of a reactive power compensating device showing a third embodiment of the present invention.

【符号の説明】[Explanation of symbols]

１、１１、１２ 交流系統 ２ リアクタンス ３ 負荷 ４ 変換用変圧器 ５ 自励式電力変換器 ６ 直流リアクトル ７ コンデンサ １０ 制御装置 ２０ 制御装置 ４５ 制御装置 ２１ 第１の変換回路 ２２ 第２の変換回路 ２３ 絶対値検出回路 ２４ 第１の演算回路 ２５ 第２の演算回路 ２６、２７ 除算回路 ３０ 第３の変換回路 ３１ 第４の変換回路 ３２、３５、３６、３９ 加算器 ３３、３７ 演算増幅回路 ３４、３８ 掛算器 ４０ 第５の変換回路 ４１ 第６の変換回路 ４２ パルス幅変調制御信号作成回路 ４３ 第７の変換回路 ４４ 第８の変換回路 ５０ 交流電流検出器 ５１、５２ 自励式電力変換器 ５３ 交流電圧検出器 ７１ コンデンサ 1, 11, 12 AC system 2 Reactance 3 Load 4 Conversion transformer 5 Self-excited power converter 6 DC reactor 7 Capacitor 10 Control device 20 Control device 45 Control device 21 First conversion circuit 22 Second conversion circuit 23 Absolute Value detection circuit 24 First arithmetic circuit 25 Second arithmetic circuit 26, 27 Division circuit 30 Third conversion circuit 31 Fourth conversion circuit 32, 35, 36, 39 Adder 33, 37 Operational amplifier circuit 34, 38 Multiplier 40 Fifth conversion circuit 41 Sixth conversion circuit 42 Pulse width modulation control signal generation circuit 43 Seventh conversion circuit 44 Eighth conversion circuit 50 AC current detector 51, 52 Self-excited power converter 53 AC voltage Detector 71 Capacitor

───────────────────────────────────────────────────── フロントページの続き (72)発明者 鈴木 健一 東京都調布市西つつじケ丘二丁目４番１号 東京電力株式会社技術研究所内 (72)発明者 中島 達人 東京都調布市西つつじケ丘二丁目４番１号 東京電力株式会社技術研究所内 (72)発明者 市川 文俊 東京都調布市西つつじケ丘二丁目４番１号 東京電力株式会社技術研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Suzuki 2-4-1 Nishitsujigaoka, Chofu-shi, Tokyo Inside the TEPCO Technical Research Institute (72) Inventor Tatsuto Nakajima 2-4-1 Nishitsujigaoka, Chofu-shi, Tokyo TEPCO Technical Research Institute (72) Inventor Fumitoshi Ichikawa 2-4-1, Nishitsujigaoka, Chofu-shi, Tokyo TEPCO Technical Research Institute

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 変換用変圧器を介して交流系統に接続さ
れる自励式電力変換器が、前記交流系統の電圧位相角の
ｃｏｓ値及びｓｉｎ値を用いて瞬時電流制御され、前記
交流系統の３相交流電圧と３相交流電流をαβの直交す
る２軸座標系成分に変換するαβ変換手段と、該αβ変
換手段により変換された信号から電圧位相角のｃｏｓ値
及びｓｉｎ値を用いてｄｑの直交する２軸座標系成分に
変換するｄｑ変換手段と、前記ｄｑ変換手段により変換
された信号とｄｑ軸座標系の前記自励式電力変換器の指
令値との偏差を求める偏差検出手段と、該偏差検出手段
の出力と前記変換用変圧器リアクタンス電圧降下を補正
してｄ軸ｑ軸指令値を発する指令値発生手段と、該指令
値発生手段の出力をαβへ変換するｄｑ逆変換手段と、
該ｄｑ逆変換手段により変換された信号を３相へ変換す
るαβ逆変換手段と、該αβ逆変換手段により変換され
た信号に応じてパルス幅変調制御信号を作成する信号発
生手段を備えた自励式電力変換器の制御装置において、
前記電圧位相のｃｏｓ値及びｓｉｎ値の検出手段が、前
記交流系統の３相交流電圧と３相交流電流をαβの直交
する２軸座標系成分に変換するαβ変換手段と、該αβ
変換手段により変換された信号から実電力及び虚電力を
計算する電力計算手段と、前記交流電圧の大きさを検出
する電圧絶対値検出手段と、前記電力計算手段の出力を
それぞれ前記電圧絶対値検出手段の出力で除算してｄｑ
座標系の電流信号に変換する電流変換手段と、前記αβ
変換手段の交流電流出力及び前記ｄｑ座標系の電流信号
に変換された信号から前記電圧位相のｃｏｓ値及びｓｉ
ｎ値を計算するｃｏ−ｓｉ算出手段からなることを特徴
とする自励式電力変換器の制御装置。1. A self-excited power converter connected to an AC system via a conversion transformer is instantaneously current controlled by using a cos value and a sin value of a voltage phase angle of the AC system. An αβ conversion means for converting a three-phase AC voltage and a three-phase AC current into two-axis coordinate system components of αβ orthogonal to each other, and dq using the cos value and the sin value of the voltage phase angle from the signal converted by the αβ conversion means. Dq conversion means for converting into two orthogonal axis system components of, and deviation detection means for obtaining a deviation between the signal converted by the dq conversion means and the command value of the self-excited power converter in the dq axis coordinate system. Command value generation means for correcting the output of the deviation detection means and the conversion transformer reactance voltage drop to generate a d-axis q-axis command value, and dq inverse conversion means for converting the output of the command value generation means into αβ. ,
A self-comprising unit comprising an αβ inverse conversion unit for converting the signal converted by the dq inverse conversion unit into three phases, and a signal generation unit for creating a pulse width modulation control signal according to the signal converted by the αβ inverse conversion unit. In the control device of the excitation power converter,
Αβ conversion means for converting the three-phase AC voltage and three-phase AC current of the AC system into a two-axis coordinate system component of αβ orthogonal to each other, the detection means for detecting the cos value and the sin value of the voltage phase, and the αβ
Power calculation means for calculating real power and imaginary power from the signal converted by the conversion means, voltage absolute value detection means for detecting the magnitude of the AC voltage, and output of the power calculation means for detecting the voltage absolute value, respectively. Divide by the output of the means and dq
Current converting means for converting into a current signal in a coordinate system, and
From the alternating current output of the converting means and the signal converted into the current signal of the dq coordinate system, the cos value of the voltage phase and si
A control device for a self-excited power converter, comprising a co-si calculating means for calculating an n value. 【請求項２】 変換用変圧器を介して交流系統に接続さ
れる自励式電力変換器が、前記交流系統の電圧位相角の
ｃｏｓ値及びｓｉｎ値を用いて瞬時電流制御され、前記
交流系統の３相交流電圧と３相交流電流をαβの直交す
る２軸座標系成分に変換するαβ変換手段と、該αβ変
換手段により変換された信号から電圧位相角のｃｏｓ値
及びｓｉｎ値を用いてｄｑの直交する２軸座標系成分に
変換するｄｑ変換手段と、前記ｄｑ変換手段により変換
された信号とｄｑ軸座標系の前記自励式電力変換器の指
令値との偏差を求める偏差検出手段と、該偏差検出手段
の出力と前記変換用変圧器リアクタンス電圧降下を補正
してｄ軸ｑ軸指令値を発する指令値発生手段と、該指令
値発生手段の出力をαβへ変換するｄｑ逆変換手段と、
該ｄｑ逆変換手段の出力を３相へ変換するαβ逆変換手
段と、該αβ逆変換手段の出力に応じてパルス幅変調制
御信号を作成する信号発生手段を含んでなる自励式電力
変換器の制御装置において、前記電圧位相のｃｏｓ値及
びｓｉｎ値の検出手段が、前記交流系統の３相交流電圧
と３相交流電流をαβの直交する２軸座標系成分に変換
するαβ変換手段と、該αβ変換手段により変換された
信号からの実電力及び虚電力を計算する電力計算手段
と、前記交流電圧の大きさを検出する電圧絶対値検出手
段と、前記電力計算手段の出力をそれぞれ前記電圧絶対
値検出手段の出力で除算してｄｑ座標系の電流信号に変
換する電流変換手段と、前記αβ変換手段の交流電流出
力及び前記ｄｑ座標系の電流信号に変換された信号から
前記電圧位相のｃｏｓ値及びｓｉｎ値を計算するｃｏ−
ｓｉ算出手段からなり、前記αβ変換手段の交流電圧出
力を、前記ｃｏ−ｓｉ算出手段の出力を用いてｄｑ座標
系電圧へ変換する電圧変換手段と、該電圧変換手段の出
力を前記指令値発生手段へ加算する手段を備えているこ
とを特徴とする自励式電力変換器の制御装置。2. A self-excited power converter connected to an AC system via a conversion transformer is subjected to instantaneous current control using the cos value and sin value of the voltage phase angle of the AC system, An αβ conversion means for converting a three-phase AC voltage and a three-phase AC current into two-axis coordinate system components of αβ orthogonal to each other, and dq using the cos value and the sin value of the voltage phase angle from the signal converted by the αβ conversion means. Dq conversion means for converting into two orthogonal axis system components of, and deviation detection means for obtaining a deviation between the signal converted by the dq conversion means and the command value of the self-excited power converter in the dq axis coordinate system. Command value generation means for correcting the output of the deviation detection means and the conversion transformer reactance voltage drop to generate a d-axis q-axis command value, and dq inverse conversion means for converting the output of the command value generation means into αβ. ,
A self-excited power converter including an αβ inverse conversion means for converting the output of the dq inverse conversion means into three phases, and a signal generation means for generating a pulse width modulation control signal according to the output of the αβ inverse conversion means. In the control device, the detection means for detecting the cos value and the sin value of the voltage phase converts the three-phase AC voltage and the three-phase AC current of the AC system into two-axis coordinate system components of αβ orthogonal to each other, and αβ conversion means, Power calculation means for calculating the real power and imaginary power from the signal converted by the αβ conversion means, a voltage absolute value detection means for detecting the magnitude of the AC voltage, and an output of the power calculation means for each of the voltage absolute values. Current conversion means for dividing by the output of the value detection means to convert into a current signal of the dq coordinate system, and the alternating current output of the αβ conversion means and the signal converted into the current signal of the dq coordinate system, the cos of the voltage phase. Value and To calculate the value in co-
voltage conversion means for converting the AC voltage output of the αβ conversion means into a dq coordinate system voltage using the output of the co-si calculation means, and the command value generation of the output of the voltage conversion means. A control device for a self-excited power converter, which is provided with means for adding to the means.