201031821 六、發明說明： 【發明所屬之技術領域】 本發明，係有關風力發電裝置以及其之控制方法。 【先前技術】 - 在互連有風車之電力系統上發生事故的話，系統電壓 . 會瞬間下降。系統電壓下降的話，在風車上會產生以下的 # 事態現象。 1) 因爲發電機輸出瞬時地下降的緣故，發生過速度 〇 2) 於發電機過渡性地流動有大電流。 3) 也於輔機之發電機過渡性地流動有大電流。 針對這樣的事態現象，爲了安全地運轉風車，例如， 一般來說進行使風車翼片的傾斜（pitch )角移動到順槳（ feather)側之所謂順槳（feathering)的控制。 ® 又，系統電壓下降的話，發電機的定子電流或轉子電 流會增加。從而，爲了抑制這些的電流增加，一般而言是 進行：使急遽斷路電路作動，使發電機的轉子繞線短路， 讓轉換器元件等因過電流而受到保護。 【發明內容】 但是，在如上所述般的發電機之狀態下，系統電壓回 復的話，對應此時的滑動而流動有較大的電流，同時發生 了較大的轉矩。 -5- 201031821 於圖4，表示有感應電機的滑動之轉矩以及電流之關 係。如圖4所示，可以瞭解到，滑動變大的話，轉矩以及 電流也一起變大。 在此，所謂的滑動，是爲以下的式（1)所表示的參 數。 滑動=(同步迴轉速-感應電機迴轉速）/同步迴轉速 （1) . 當滑動比零大的時候，感應電機係當作電動機來運作 ;當滑動比零小的時候，感應電機馬達係當作發電機（再 0 生運轉）來運作。 本發明，其目的在於提供有：抑制系統電壓回復時之 轉矩的上升，來可以減.低因轉矩對機器的負荷之風力發電 裝置以及其之控制方法。 本發明之第1樣態，係爲一種風力發電裝置，具備有 :發電機，和把前述發電機轉子的輸出從三相交流電力變 換成直流電力之轉換器，和把從前述轉換器所輸出的直流 電力變換成3相交流電力之換流器，和控制前述轉換器以 ❹ 及前述換流器之電力控制部；前述電力控制部，根據前述 發電機的轉子電流或者是利用前述轉換器所變換出的直流 電壓，來控制前述轉換器以及前述換流器之作動之停止/ 再開；其特徵在於，具有控制風車翼片的傾斜角之葉片控 制部；前述葉片控制部，係藉由前述電力控制部，在停止 前述轉換器以及前述換流器之作動的情況下，以使前述發 電機的迴轉數成爲同步迴轉速或者是同步迴轉速以上的方 式，來控制風車翼片的傾斜角，藉由前述電力控制部，在 -6- 201031821 再開前述轉換器以及前述換流器之作動的情況下，以與根 據風速、前述發電機的迴轉速、以及要求輸出之至少其中 任一個所決定出的目標傾斜角一致的方式，來控制風車翼 片的傾斜角。 如此，在轉換器以及換流器中，不拘於電力系統的狀 - 態，因應發電機的轉子電流或是利用前述變壓器所變換出 . 的直流電壓的狀態來決定作動之停止。該控制，係以往以 Φ 來一般所進行的控制。從而，沒有必要去設置用來檢測系 統電壓是否下降之新的感測器等，使用以往的技術可以去 檢測系統電壓的下降等。接著，於停止轉換器等的作動之 情況下，葉片控制部，係以使發電機的迴轉速成爲同步迴 轉速或者是同步迴轉速以上的方式，來控制風車翼片的傾 斜角的緣故，可以防止回復系統電壓且再開轉換器以及換 流器的控制時之較大的轉矩的發生或者是反負載轉矩的發 生。由此，可以減低因轉矩而對機器的負荷。 上述風力發電裝置，係具有急遽斷路電路，爲連接到 前述發電機的轉子繞線，在流動在該轉子繞線的電流爲既 定之電流閾値以上之情況或者是利用前述轉換器所變換出 的直流電壓爲既定的電壓閾値以上之情況下進行作動，使 轉子繞線短路；前述葉片控制部，係前述急遽斷路電路作 動，且藉由前述電力控制部，在前述轉換器以及前述換流 器的作動被停止的情況下，以前述發電機的迴轉速爲同步 迴轉速或者是同步迴轉速以上的方式，來控制風車翼片的 傾斜角；前述急遽斷路電路進行作動停止，且藉由前述電 201031821 力控制部，再開前述轉換器以及前述換流器的作動之情況 下’以與根據風速、前述發電機的迴轉速、以及要求輸出 之至少其中一個所決定的傾斜角一致的方式，來控制風車 翼片的傾斜角亦可。 如此，於具有急遽斷路電路之情況下，轉換器以及換 流器的作動狀態之外，考慮急遽斷路電路的作動狀態後來 作爲切換風車翼片的傾斜角控制也是可以的。 本發明之第2樣態，係爲一種風力發電裝置之控制方 _ 法，具備有：發電機，和把前述發電機轉子的輸出從三相 交流電力變換成直流電力之轉換器，和把從前述轉換器所 輸出的直流電力變換成3相交流電力之換流器，和控制前 述轉換器以及前述換流器之電力控制部；前述電力控制部 ，根據前述發電機的轉子電流或者是利用前述轉換器所變 換出的直流電壓，來控制前述轉換器以及前述換流器之作 動之停止·再開；其特徵在於，藉由前述電力控制部，在 停止前述轉換器以及前述換流器之作動的情況下，以使前 @ 述發電機的迴轉數成爲同步迴轉速或者是同步迴轉速以上 的方式，來控制風車翼片的傾斜角，藉由前述電力控制部 ，在再開前述轉換器以及前述換流器之作動的情況下，以 與根據風速、前述發電機的迴轉速、以及要求輸出之至少 其中任一個所決定出的目標傾斜角一致的方式，來控制風 車翼片的傾斜角。 若由本發明，可以發揮抑制系統電壓回復時之轉矩的 上升，來可以減低因轉矩對機器的負荷之效果。 -8- 201031821 【實施方式】 於以下，關於本發明之風力發電裝置及其之控制方法 之一實施型態，參閱圖面來說明之。 圖1，係表示有關本實施型態的風力發電裝置之全體 - 構成之方塊圖。風力發電裝置1，係如圖1所示般地，具 . 有支柱2、和設置在支柱2的上端之短艙3、和設於短艙3 且可以迴轉在略水平的軸線周圍之轉子頭4。於轉子頭4 ，在該迴轉軸線周圍放射狀地安裝有3片風車翼片5。由 此，從轉子頭4的迴轉軸線方向上碰觸到風車翼片5的風 之力，被變換成使轉子頭4迴轉在迴轉軸線周圍的動力； 該動力爲藉由收容在短艙3內的發電機來變換成電能。 又，於短艙3，設有風速風向計（圖示省略）。風速 風向計，係測定風速與風向。短艙3，係對應藉由風速風 向計所測定出的風速與風向來迴旋。 •圖2，係表示發電機6及其周邊的構成之一例之方塊 圖。於本實施型態，發電機（感應電機）6,係以發電機6 所產生的電力可以從定子繞線及轉子繞線之兩方書出道電 力系統13的方式來構成。具體而言，發電機6，係該定子 繞線連接到電力系統13，轉子繞線爲介隔著AC-DC-AC 轉換器17連接到電力系統13。 AC-DC-AC轉換器17，係事先由轉換器14、DC匯流 排15、以及換流器16來構成，把從轉子繞線所接受的交 流電力變換成適合電力系統13的頻率之交流電力。轉換 -9- 201031821 器14,係把產生在轉子繞線之交流電力變換成直流電力， 把該直流電力輸出到DC匯流排15。換流器16,係把從 DC匯流排15所接受的直流電力變換成與電力系統13同 一的頻率之交流電力，輸出該交流電力。 AC-DC-AC轉換器17，係也具有把從電力系統13所 接受的交流電力變換成適合轉子繞線的頻率之交流電力的 功能，藉由風力發電裝置1之運轉的狀況也使用用來激勵 轉子繞線。該情況下，換流器16,係把交流電力變換成直 Q 流電力，把該直流電力輸出到DC匯流排15。轉換器14， 係把從DC匯流排15所接受的直流電力變換成適合於轉子 繞線的頻率之交流電力，把該交流電力供給到發電機5的 轉子繞線。 又，於轉子繞線，連接有用於轉換器14的過電流保 護之急遽斷路電路27。急遽斷路電路27，係流動在轉子 繞線的電流或者是DC匯流排15的電壓超過既定的閾値之 情況下進行作動，使轉子繞線透過組抗來短路。由此，使 ❹ 轉子繞線的電流衰減，過電流不會流動到轉換器14。尙且 ，不透過組抗使其直接短路也是可以的。 又，於把發電機5連接到電力系統13之電力線方面 ，設有計測發電機5的輸出電壓V與輸出電流I之電壓/ 電流感測器（圖示省略）。該電壓/電流感測器的計測値 ，係賦予到電力控制部2 1。201031821 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a wind power generation device and a control method therefor. [Prior Art] - If an accident occurs on a power system interconnected with a windmill, the system voltage will drop instantaneously. When the system voltage drops, the following # events will occur on the windmill. 1) The overspeed occurs because the generator output drops instantaneously 〇 2) The generator has a large current flowing transiently. 3) The generator that is also in the auxiliary machine has a large current flowing transiently. In order to operate the wind turbine safely, for example, in general, the so-called feathering control for moving the pitch angle of the windmill blade to the feather side is generally performed. ® In addition, if the system voltage drops, the stator current or rotor current of the generator will increase. Therefore, in order to suppress the increase of these currents, it is generally performed to operate the sudden breaking circuit to short-circuit the rotor of the generator, and to protect the converter element or the like from overcurrent. SUMMARY OF THE INVENTION However, in the state of the generator as described above, when the system voltage is recovered, a large current flows in response to the slip at this time, and a large torque is generated at the same time. -5- 201031821 In Figure 4, there is a relationship between the torque of the sliding of the induction motor and the current. As shown in Fig. 4, it can be understood that the torque and the current also become larger as the slip becomes larger. Here, the sliding is a parameter represented by the following formula (1). Sliding = (synchronous return speed - induction motor return speed) / synchronous return speed (1). When the sliding ratio is greater than zero, the induction motor is operated as a motor; when the sliding ratio is less than zero, the induction motor is Act as a generator (re-running). SUMMARY OF THE INVENTION An object of the present invention is to provide a wind power generator capable of reducing an increase in torque when a system voltage is restored, and a method of controlling the load on a machine due to a torque. According to a first aspect of the present invention, a wind power generator includes: a generator; and a converter that converts an output of the generator rotor from three-phase AC power to DC power, and outputs the output from the converter The DC power is converted into a three-phase AC power converter, and the power converter is controlled by the converter and the inverter; the power control unit is based on the rotor current of the generator or by using the converter. a DC voltage that is converted to control the stop/reopen of the converter and the operation of the inverter; and a blade control unit that controls an inclination angle of the windmill blade; the blade control unit is powered by the power When the control unit stops the operation of the converter and the inverter, the control unit controls the tilt angle of the windmill blade so that the number of revolutions of the generator is equal to or greater than the synchronous return speed. By the power control unit, when the converter and the inverter are operated by -6-201031821, , The rotation speed of the generator, and wherein at least one of any of the same target inclination angle determined that the required output of the embodiment, to control the tilt angle of the windmill blades. As described above, in the converter and the inverter, regardless of the state of the electric power system, the stop of the operation is determined in accordance with the rotor current of the generator or the state of the DC voltage converted by the transformer. This control is a conventional control performed by Φ. Therefore, it is not necessary to provide a new sensor or the like for detecting whether or not the system voltage is lowered, and the conventional technique can be used to detect a drop in the system voltage. Then, when the operation of the converter or the like is stopped, the blade control unit controls the tilt angle of the windmill blade so that the return rotational speed of the generator becomes the synchronous return rotational speed or the synchronous return rotational speed or the like. The occurrence of a large torque that prevents the return of the system voltage and reopening of the converter and the control of the inverter or the occurrence of the counter load torque. Thereby, the load on the machine due to the torque can be reduced. The wind power generator includes a sudden breaking circuit, and is a rotor winding connected to the generator, and a current flowing through the rotor winding is equal to or greater than a predetermined current threshold or a DC converted by the converter. When the voltage is equal to or higher than a predetermined voltage threshold ,, the rotor winding is short-circuited; the blade control unit is operated by the sudden breaking circuit, and the converter and the converter are operated by the power control unit. When the vehicle is stopped, the tilt angle of the wind turbine blade is controlled such that the return speed of the generator is equal to or greater than the synchronous return speed; the sudden circuit breaker is actuated to stop, and the power is 201031821 The control unit controls the wind turbine blade so as to match the inclination angle determined according to at least one of the wind speed, the return rotational speed of the generator, and the required output when the converter and the inverter are operated. The tilt angle of the sheet can also be used. As described above, in the case of the emergency circuit, in addition to the operating state of the converter and the converter, it is also possible to control the tilt angle of the wind turbine blade as the switching state of the switch circuit. According to a second aspect of the present invention, there is provided a method of controlling a wind power generator, comprising: a generator, and a converter for converting an output of the generator rotor from three-phase AC power to DC power, and An inverter that converts DC power outputted by the converter into three-phase AC power, and a power control unit that controls the converter and the inverter; and the power control unit uses the rotor current of the generator or the aforementioned a DC voltage converted by the converter controls the stop and reopening of the converter and the operation of the inverter; wherein the power control unit stops the operation of the converter and the inverter In this case, the inclination angle of the windmill blade is controlled so that the number of revolutions of the former generator is equal to or greater than the synchronous return speed, and the converter and the aforementioned converter are reopened by the power control unit. In the case of the operation of the flow device, at least one of the wind speed, the return speed of the aforementioned generator, and the required output Fix target tilting angle consistent manner, to control the tilt angle of windmill wings. According to the present invention, it is possible to reduce the torque at the time of returning the voltage of the system, and it is possible to reduce the effect of the load on the machine due to the torque. -8-201031821 [Embodiment] Hereinafter, one embodiment of a wind power generator and a control method therefor according to the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing the overall configuration of a wind power generator of the present embodiment. The wind power generator 1, as shown in Fig. 1, has a pillar 2, a nacelle 3 disposed at an upper end of the pillar 2, and a rotor head provided in the nacelle 3 and rotatable about a slightly horizontal axis 4. In the rotor head 4, three windmill blades 5 are radially mounted around the rotation axis. Thereby, the force of the wind that hits the windmill blade 5 from the direction of the rotation axis of the rotor head 4 is converted into the power that causes the rotor head 4 to rotate around the rotation axis; the power is housed in the nacelle 3 The generator is transformed into electrical energy. Further, in the nacelle 3, a wind speed and direction meter (not shown) is provided. Wind speed Wind direction meter measures the wind speed and direction. The nacelle 3 corresponds to the wind speed and the wind direction measured by the wind speed and direction meter. Fig. 2 is a block diagram showing an example of the configuration of the generator 6 and its surroundings. In the present embodiment, the generator (induction motor) 6 is constructed such that the electric power generated by the generator 6 can be derived from the stator winding power system 13 of the stator winding and the rotor winding. Specifically, the generator 6 is connected to the power system 13 by a winding of the stator, and the rotor winding is connected to the power system 13 via an AC-DC-AC converter 17. The AC-DC-AC converter 17 is configured in advance by the converter 14, the DC busbar 15, and the inverter 16, and converts AC power received from the rotor winding into AC power suitable for the frequency of the power system 13. . The conversion -9-201031821 converts the AC power generated in the rotor winding into DC power, and outputs the DC power to the DC bus. The inverter 16 converts the DC power received from the DC bus bar 15 into AC power of the same frequency as the power system 13, and outputs the AC power. The AC-DC-AC converter 17 also has a function of converting AC power received from the power system 13 into AC power suitable for the frequency of the rotor winding, and the operation of the wind power generator 1 is also used. Exciting the rotor winding. In this case, the inverter 16 converts the AC power into the direct Q stream power, and outputs the DC power to the DC bus bar 15. The converter 14 converts the DC power received from the DC busbar 15 into AC power suitable for the frequency of the rotor winding, and supplies the AC power to the rotor winding of the generator 5. Further, a sudden breaking circuit 27 for overcurrent protection of the converter 14 is connected to the rotor winding. The slamming circuit 27 is operated when the current flowing through the rotor or the voltage of the DC bus 15 exceeds a predetermined threshold ,, and the rotor winding is short-circuited by the group resistance. Thereby, the current of the winding of the 转子 rotor is attenuated, and the overcurrent does not flow to the converter 14. Moreover, it is also possible to make a direct short circuit without passing through the group. Further, in connection with the power line connecting the generator 5 to the power system 13, a voltage/current sensor (not shown) for measuring the output voltage V of the generator 5 and the output current I is provided. The measurement 値 of the voltage/current sensor is applied to the power control unit 21 .
電力控制部21，係爲了能夠針對應答於有效電力指令 P*、無效電力指令Q*後輸出的有效電力P與無效電力Q -10- 201031821 來進行控制，控制轉換器14的功率電晶體之開關。具體 而言，電力控制部2 1，係從藉由電壓/電流感測器所測定 出的輸出電壓V與輸出電流I，來算出有效電力P與無效 電力Q。更進一步，電力控制部21，係生成把有效電力P 與有效電力指令P*的差、以及無效電力Q與無效電力指 - 令Q*的差當作零般的PWM訊號，把已生成的PWM訊號The power control unit 21 controls the switching of the power transistor of the converter 14 in order to control the effective power P and the reactive power Q -10- 201031821 that are output after responding to the effective power command P* and the reactive power command Q*. . Specifically, the power control unit 21 calculates the effective power P and the reactive power Q from the output voltage V and the output current I measured by the voltage/current sensor. Further, the power control unit 21 generates a PWM signal in which the difference between the effective power P and the effective power command P* and the difference between the invalid power Q and the invalid power command-Q* are regarded as zero, and the generated PWM is generated. Signal
. 供給到轉換器14。由此，來控制有效電力P與無效電力Q 0 電力控制部2 1，係事先監視發電機轉子電流以及DC 連結電壓，這些値超過預先設定好的電流閾値、電壓閾値 時，使急遽斷路電路27作動的同時，把轉換器14以及換 流器16的切換切換成關（OFF )。該控制，係一般所進行 的控制。 如此，對應系統電壓的舉動，不是使急遽斷路電路27 等進行作動，利用上述發電機轉子電流以及DC連結電壓 ©的舉動來切換控制內容的緣故，是沒有必要爲了檢知系統 電壓下降，而去追加新的功能、或是設定新的判斷基準。 葉片控制部22，係應答於傾斜指令Θ *，來控制風車 翼片5的傾斜角肩。具體而言，葉片控制部22,係以使風1 車翼片5的傾斜角yS —致於傾斜指令点*的方式來進行控 制。 接著，有關於與系統電壓已下降的情況之本實施型態 相關的風力發電裝置之控制方法，參閱圖3說明之。 首先，於系統側發生事故等，系統電壓下降的話，發 -11 - 201031821 電機6的轉子電流增加的同時，DC連結15的電壓（換言 之，利用轉換器I4所變換出的直流電壓）也增加。 電力控制部21’係判定發電機6的轉子電流是否爲預 先設定好的電流閾値以上、以及、DC連結15的電壓是否 爲預先設定好的電壓閾値以上（步驟AS1)，這些電流以 及電壓之至少其中一方爲超過各自的閾値之情況（步驟 SA1中的「YES」）下，使急遽斷路電路27作動的同時， 使轉換器14以及換流器16的作動停止（步驟SA2)。 參 由此，急遽斷路電路27作動，轉子繞線透過阻抗來 短路。又，利用使轉換器14以及換流器16的驅動停止的 方式，停止對電力系統13的電力供給。 又，電力控制部21，係把使急遽斷路電路27作動爲 主旨的訊號輸出到葉片控制部22。葉片控制部22，係接 受急遽斷路電路27的作動開始的話，以發電機6的迴轉 速成爲同步迴轉速或是同步迴轉速以上的方式，來控制風 車翼片的傾斜角（步驟S A3)。由此，發電機6的迴轉速 © ，係維持在同步迴轉速或者是同步迴轉速以上。 接著，系統電壓回復，電力控制部21，爲判定轉子電 流是否成爲特定的設定値以下、或者是DC連結15的電壓 爲特定的設定値以下的話（步驟SA4中的「YES」），電 力控制部21，係使急遽斷路電路27的作動停止的同時， 再開轉換器14以及換流器16的驅動（步驟SA5)。 又，電力控制部21，係把使急遽斷路電路27的作動 停止爲主旨的訊號輸出到葉片控制部22。葉片控制部22 -12- 201031821 ’係接受急遽斷路電路27的作動停止的話，讓風車翼片 的傾斜角控制回到通常模式（步驟SA6 )。亦即，葉片控 制部22，係以與根據風速、發電機6的迴轉速、以及要求 輸出之至少其中任一個所決定出的目標傾斜角一致的方式 ，來控制風車翼片的傾斜角。 - 如此，若於有關本實施型態的風力發電裝置及其之控 - 制方法中，在停止轉換器14以及換流器16的期間，因爲 • 是以使發電機的迴轉速成爲同步迴轉速的方式來控制風車 翼片的傾斜角的緣故，系統電壓復歸，可以讓轉換器14 以及換流器16開始驅動後之發電機6的滑動爲零或者是 近似於零的値。 由此，可以抑制於系統電壓的回復時所過渡性發生的 轉矩的增加，使得可以迴避因轉矩增加而對機器的影響。 特別是，可以迴避因轉矩上升而導致對增速機（Step-up gear )的齒輪之影響。 β 尙且，在上述實施型態，使轉換器14以及換流器16 的作動停止，且，急遽斷路電路27已作動的情況下，切 換了風車翼片的傾斜角控制，但是，替代這些的方案，例 如，是否使轉換器14以及換流器16的作動停止，或者是 ，急遽斷路電路27已作動的情況下，以使發電機6的迴 轉速成爲同步迴轉速或者是同步迴轉速以上的方式來控制 風車翼片的傾斜角也是可以的。 又，使急遽斷路電路作動的條件，與使轉換器14以 及換流器16的作動停止的條件相異也是可以的。 -13- 201031821 【圖式簡單說明】 〔圖1〕表示有關本發明之一實施型態的風力發電裝 置之全體構成之方塊圖。 〔圖2〕表示發電機及其周邊的構成之一例之方塊圖 〇 〔圖2〕說明有關本發明之一實施型態的風力發電裝 置的控制之流程。 〔圖4〕表示針對感應電機的滑動之轉矩以及電流之 關係的圖。 【主要元件符號說明】 1 :風力發電裝置 3 :短艙（nacelle ) 5 :風車翼片 6 :發電機 13 :電力系統 14 :轉換器（converter) 1 5 : D C匯流排 16 :換流器（inverter) 1 7 : AC-DC-AC 變壓器 2 1 :電力控制部 2 2 :葉片控制部 27 :急遽斷路電路（crowbar circuit)Supply to converter 14. Thereby, the effective power P and the reactive power Q 0 are controlled. The power control unit 2 1 monitors the generator rotor current and the DC connection voltage in advance, and when the 値 exceeds the preset current threshold 电压 and the voltage threshold ,, the sudden breaking circuit 27 is caused. At the same time as the actuation, the switching of the converter 14 and the inverter 16 is switched to OFF. This control is generally controlled. In this way, in response to the behavior of the system voltage, the sudden breaking circuit 27 or the like is not operated, and the control content is switched by the behavior of the generator rotor current and the DC connection voltage ©, and it is not necessary to detect the system voltage drop. Add new features or set new benchmarks. The blade control unit 22 controls the tilt shoulder of the windmill blade 5 in response to the tilt command Θ*. Specifically, the blade control unit 22 controls the inclination angle yS of the wind 1 wing panel 5 so as to be inclined to the command point*. Next, a control method of the wind power generator relating to the present embodiment in which the system voltage has dropped will be described with reference to Fig. 3 . First, an accident occurs on the system side, and if the system voltage drops, the rotor current of the motor 6 increases while the voltage of the DC link 15 (in other words, the DC voltage converted by the converter I4) increases. The power control unit 21' determines whether or not the rotor current of the generator 6 is equal to or higher than a preset current threshold 、, and whether the voltage of the DC link 15 is equal to or higher than a predetermined voltage threshold (step AS1), and at least these currents and voltages When one of them is beyond the threshold ("YES" in step SA1), the sudden breaking circuit 27 is actuated, and the operation of the converter 14 and the inverter 16 is stopped (step SA2). As a result, the slamming circuit 27 is actuated, and the rotor winding is short-circuited by the impedance. Further, the supply of electric power to the electric power system 13 is stopped by stopping the driving of the converter 14 and the inverter 16. Further, the power control unit 21 outputs a signal for causing the sudden circuit breaker 27 to operate to the blade control unit 22. When the operation of the sudden breaking circuit 27 is started, the blade control unit 22 controls the inclination angle of the windshield such that the rotational speed of the generator 6 becomes equal to or higher than the synchronous return rotational speed (step S A3). Thereby, the return speed © of the generator 6 is maintained at or above the synchronous return speed. Then, when the system voltage is restored, the power control unit 21 determines whether the rotor current is equal to or less than the specific setting 、 or the voltage of the DC link 15 is equal to or lower than the specific setting ( (YES in step SA4). 21, the operation of the sudden breaking circuit 27 is stopped, and the driving of the converter 14 and the inverter 16 is resumed (step SA5). Further, the power control unit 21 outputs a signal for stopping the operation of the sudden breaking circuit 27 to the blade control unit 22. When the operation of the sudden breaking circuit 27 is stopped, the blade control unit 22 -12- 201031821 returns the inclination angle of the wind turbine blade back to the normal mode (step SA6). That is, the blade control unit 22 controls the inclination angle of the windmill blade so as to match the target inclination angle determined based on at least one of the wind speed, the rotational speed of the generator 6, and the required output. - In the case of the wind power generator of the present embodiment and the control method thereof, during the stop of the converter 14 and the inverter 16, because the return speed of the generator is synchronized to the rotational speed By way of controlling the tilt angle of the windmill fins, the system voltage resets, allowing the converter 14 and the generator 6 to start driving the generator 6 to slide zero or near zero. Thereby, it is possible to suppress an increase in the torque which is transiently generated when the system voltage is recovered, so that the influence on the machine due to the increase in torque can be avoided. In particular, it is possible to avoid the influence of the gear of the step-up gear due to the rise in torque. In the above embodiment, the operation of the converter 14 and the inverter 16 is stopped, and when the sudden breaking circuit 27 is activated, the inclination angle control of the windmill blade is switched, but instead of these For example, whether or not the operation of the converter 14 and the inverter 16 is stopped, or when the rapid circuit breaker 27 is activated, the return speed of the generator 6 is set to be synchronous return speed or synchronous return speed or higher. It is also possible to control the tilt angle of the windmill fins. Further, the conditions for operating the sudden circuit breaker may be different from the conditions for stopping the operation of the converter 14 and the inverter 16. -13-201031821 [Brief Description of the Drawings] Fig. 1 is a block diagram showing the overall configuration of a wind power generating apparatus according to an embodiment of the present invention. Fig. 2 is a block diagram showing an example of a configuration of a generator and its surroundings. Fig. 2 is a flow chart showing the control of a wind power generator according to an embodiment of the present invention. Fig. 4 is a view showing the relationship between the torque and the current of the sliding of the induction motor. [Explanation of main component symbols] 1 : Wind power generation device 3 : nacelle 5 : windmill blade 6 : generator 13 : power system 14 : converter (converter ) 1 5 : DC bus bar 16 : converter ( Inverter 1 7 : AC-DC-AC transformer 2 1 : power control unit 2 2 : blade control unit 27 : crowbar circuit