JP4449775B2 - Secondary excitation power converter - Google Patents

Description

  The present invention relates to a power converter for AC excitation of a secondary winding that suppresses an overcurrent generated in the secondary winding of a secondary excitation generator from flowing into the power converter due to disturbance of the power system, and to use the same. Related to the power generator.

  The secondary excitation generator (winding induction generator) used in the power generator generates an AC voltage with the same frequency as the system frequency on the stator side by exciting the rotor winding with a power converter at a slip frequency. There is an advantage that the rotational speed can be made variable and the capacity of the power converter can be made smaller than the capacity of the generator.

  When a voltage drop occurs due to a power system ground fault or the like, the secondary excitation generator operates to supply current to the point of the accident. At this time, an excessive current is induced in the secondary winding, and an excessive current flows in the excitation power converter connected to the secondary side. For example, a method such as installing an AC reactor that shortens the secondary winding or the like is used. Patent Document 1 discloses changing the parallel number of power conversion means to be turned on according to the instantaneous inflow power amount.

Japanese Patent Laid-Open No. 11-18486 (described in paragraph (0004))

  When the secondary winding is short-circuited by the AC reactor, the power converter is temporarily stopped, so it takes time to restart and supply power again. In addition, increasing the capacity of the power converter increases the cost of the system and impairs the characteristics of the system using the secondary excitation generator. In addition, when the secondary winding is short-circuited by an AC reactor, the power converter is temporarily stopped and the excessive current is removed, and then the short-circuit is opened and restarted. Therefore, it takes time to supply power again. Take it.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a secondary excitation power converter capable of achieving both protection from overcurrent caused by a system fault or system disturbance and continued operation of the power converter for the excitation power converter of the secondary excitation generator. Is to provide.

  In order to prevent the overcurrent generated in the secondary winding of the secondary excitation generator from flowing through the power converter when the system is disturbed, the present invention installs a rectifier through a reactor in parallel with the power converter, The overcurrent flowing from the secondary winding is shunted to the rectifier, and the amount flowing into the power converter is reduced.

  The power converter of the present invention can reduce the current capacity of the power converter in order to prevent the overcurrent generated in the secondary winding of the secondary excitation generator from flowing through the power converter when the system is disturbed.

  In the present invention, the excitation power converter of the secondary excitation generator is protected from overcurrent due to system disturbance, and the impedance of the rectifier, which is an overcurrent processing device, is lowered in order to continue operation. The details of the present invention will be described below with reference to the drawings.

  FIG. 1 is a single-line connection diagram showing a device configuration of the present embodiment. Here, the case of a wind turbine generator will be described, but the present invention can also be applied to the case of using a power source other than the wind turbine 101.

  First, an electrical wiring and device for outputting generated power will be described. The wind power generator Gen is a secondary excitation generator (winding induction generator), and the three-phase AC output on the stator side (primary side) of the generator Gen is an electromagnetic that can be opened and closed by an external signal. Connected to the secondary side of the contactor CTT1. The primary side of the magnetic contactor CTT1 is connected to the primary side of the magnetic contactor CTT2 and the secondary side of the circuit breaker BR. The primary side of the circuit breaker BR is connected to a power system (not shown).

  The circuit breaker BR has, for example, a function of opening the circuit breaker and cutting off the current when the current is excessive, and when the circuit breaker BR is turned on, power is supplied to the control device CTRL of the wind turbine generator. A battery device such as an uninterruptible power supply is used to supply power to the control device CTRL even when a system failure occurs.

  In addition, the secondary side of the magnetic contactor CTT2 is connected to the AC output terminal of the power converter CNV for interconnection via a delta-connected capacitor Cn and a reactor Ln. On the other hand, the DC output terminal of the interconnection power converter CNV is connected to the DC output terminal of the excitation power converter INV via a DC smoothing capacitor Cd.

  The power converter CNV for interconnection and the power converter INV for excitation are configured using, for example, semiconductor power switching elements (thyristors, GTOs, IGBTs, power MOSFETs), and each converts AC to DC or It has a function to convert direct current to alternating current.

  The AC output terminal of the power converter INV for excitation is connected to the secondary winding terminal of the generator Gen via the reactor Lr and the capacitor Cr.

  The rectifier REC is connected to the secondary winding terminal of the generator Gen via the reactor Lx in parallel with the excitation power converter. The rectifier REC is connected to the DC portion of the power converter INV, for example, the smoothing capacitor Cd, and further connected to an energy consuming device LOD having a power semiconductor switch and a resistor. In the following description, the case where the rectifier REC includes a diode rectifier will be described. However, the semiconductor rectifier is not limited to a diode rectifier, and a semiconductor power switching element (thyristor, GTO, IGBT, power MOSFET) may be used. Further, in this embodiment, the rotor of the generator Gen is connected to the windmill 101 directly or via a gear or the like, and rotates with the rotation of the windmill. The same applies to the case of rotating with the power of the internal combustion machine, flywheel or the like.

  Next, wiring and devices for controlling the generated power will be described. The three-phase voltage and three-phase current on the primary side of the circuit breaker BR are converted into low voltage signals Vs and Is by the voltage sensor PTs and current sensor CTs, respectively, and the low voltage signal is input to the control device CTRL. Is done.

  Further, the voltage on the secondary side of the magnetic contactor CTT1, that is, the voltage between the magnetic contactor CTT1 and the generator stator, is converted into a low voltage signal Vg by the voltage sensor PTg and input to the control device CTRL. . Further, the secondary side of the magnetic contactor CTT2, that is, the three-phase current between the magnetic contactor CTT2 and the power converter CNV is converted into a low voltage signal In by the current sensor CTn, and the low voltage signal Is input to the control device CTRL.

  Further, the rotational speed and position of the generator Gen are detected by a position detector (for example, the encoder 102), and the phase signal PLr (pulse train) is input to the control device CTRL.

  Further, the voltage of the smoothing capacitor Cd connected to the DC sections of the power converters CNV and INV is converted into a low voltage signal Edc by a voltage sensor (not shown), and this signal Edc is input to the control device CTRL.

  Next, functions of the control device CTRL will be described with reference to FIG. The control device CTRL controls the electromagnetic contactors CTT1, CTT2, the power converters INV, CNV, and the energy consuming device LOD with signals Sg1, Sg2, Pulse_inv, Pulse_cnv, Pulse_LOD.

  The grid-connected power converter CNV controls the DC voltage Edc of the smoothing capacitor Cd to be constant from when the wind turbine generator is in operation and before and after the generator Gen is connected to the power system by the electromagnetic contactor CTT1. DC voltage control and zero system reactive power (power factor 1) control are performed. Accordingly, if the DC voltage drops as a result of the use of the DC power by the excitation power converter INV, the interconnection power converter CNV takes out the power from the power system and charges the DC voltage to the smoothing capacitor Cd to make it constant. On the other hand, when the excitation power converter INV charges the smoothing capacitor Cd and the DC voltage across the smoothing capacitor Cd rises, the interconnection power converter CNV generates DC power. It converts to AC power and discharges, and operates to keep the DC voltage constant.

  First, the control of the power converter CNV will be described in detail. The AC voltage detection value Vs is input to the three-phase / two-phase converter 32trs. The outputs Vα and Vβ of the three-phase / two-phase converter 32trs are input to the phase detector THDET. The phase detector THDET calculates a phase signal THs that follows the voltage of the system by, for example, a phase locked loop (PLL) system, and the phase signal THs is calculated using the three-phase two-phase coordinate converter 32dqtrs and the 2 Output to the phase / three-phase coordinate converter dq23trs. The DC voltage command value Eref and the DC voltage detection value Edc are input to a DC voltage regulator DCAVR constituted by, for example, a proportional integration controller. The DC voltage regulator DCAVR adjusts the output d-axis current command value (effective current command value) Idnstr so that the deviation between the input command value and the detected value becomes zero, and the current regulator 1-ACR Output to.

  The three-phase / two-phase coordinate converter 32dqtrs uses the conversion formula shown in the formula (1) from the input current In, and detects the d-axis current detection value Idn (effective current) and the q-axis current detection value Iqn (invalidity). Current) is calculated, and the d-axis current detection value Idn is output to the current regulator 1-ACR, and the q-axis current detection value Iqn is output to the current regulator 2-ACR.

  The current adjuster 1-ACR adjusts the output d-axis voltage command value Vdn0 so that the deviation between the d-axis current command value Idnstr and the d-axis current detection value Idn is zero, and outputs it to the adder 301. . Similarly, the current regulator 2-ACR outputs the q-axis of the output so that the deviation between the q-axis current command value (command value = 0 when the power factor is 1) and the q-axis current detection value Iqn is zero. Voltage command value Vqn0 is adjusted and output to adder 302. Here, the current regulators 1-ACR and 2-ACR can be constituted by, for example, a proportional integral controller.

  The voltage coordinate converter dqtrs detects the d-axis voltage (phase component that matches the system voltage vector) using the conversion equation shown in the equation (2) from the α component Vα and β component Vβ of the input voltage Vs. Vds and a q-axis voltage detection value (component orthogonal to the d-axis voltage detection value Vds) Vqs are calculated and output to the adders 301 and 302, respectively.

  The adder 301 adds the d-axis voltage command value Vdn0 and the d-axis voltage detection value Vds and outputs the result to the two-phase / three-phase coordinate converter dq23trs. Similarly, the adder 302 adds the q-axis voltage command value Vqn0 and the q-axis voltage detection value Vqs and outputs the result to the two-phase / three-phase coordinate converter dq23trs.

  The two-phase / three-phase coordinate converter dq23trs receives the phase signal Ths and the results Vdn and Vqn of the adders, and converts the converter according to the conversion formulas shown in the formulas (3) and (4). The voltage command values Vun, Vvn, and Vwn output from are calculated and output to the PWM calculator PWMn.

  The PWM calculator PWMn calculates a gate signal Pulse_cnv for turning on / off n power semiconductor elements constituting the power converter CNV by a pulse width modulation method from input voltage commands Vun, Vvn, Vwn, and Output to the power converter CNV.

  Next, control of the power converter INV will be described. A phase signal PLr indicating the rotational speed and position of the generator is input to the rotational phase detector ROTETET. The rotational phase detector ROTDET counts the phase signal pulse PLr and converts it to a phase signal, and resets the phase signal to 0 with one pulse per rotation (for example, a Z-phase pulse in an ABZ encoder) A phase signal RTH of 0 to 360 degrees that does not overflow is output to the adder 303.

  The phase signal RTH and the output phase signal LTH of the synchronous controller SYNC are added by the adder 303 to become the phase signal TH, and the phase signal TH is input to the excitation phase calculator SLDET together with the phase signal THs.

  The excitation phase calculator SLDET subtracts the phase signals TH and THs (THr = THs−TH), further multiplies the number of pole pairs of the generator, and outputs a phase signal THr of the electrical angular frequency of the generator rotor. .

  The power calculator PQCAL orthogonally intersects the d-axis current Ids that is in the same direction as the U-phase vector of the system voltage detected by the conversion formula shown in the equation (1) with the system current Is and the U-phase vector of the system voltage. The q-axis current Iqs, the d-axis voltage detection value Vds, and the q-axis voltage detection value Vqs are input, and the active power Ps and the reactive power Qs of the system are calculated according to the equation (5).

  The active power adjuster APR receives the active power Ps and the output power command Pref of the wind turbine generator, and sets the output torque current command value Iq0 so that the deviation between the power command value Pref and the detected power value Ps is zero. Output.

  The reactive power adjuster AQR receives the reactive power Qs and the output power command Qref of the wind turbine generator, and outputs an exciting current command value so that the deviation between the power command value Qref and the detected power value Qs becomes zero. Id0 is output. Here, the power regulator APR and the reactive power regulator AQR can be constituted by, for example, a proportional integrator.

  A torque current command value Iq0 and an excitation current command value Id0, which are current command values of the outputs of the power regulator APR and reactive power regulator AQR, are input to the switch SW.

  Whether the switch SW uses the outputs of the active power regulator APR and the reactive power regulator AQR, or uses zero for the torque current command value Iq0 and the output of the voltage regulator for the excitation current command value Id0. decide. Here, the switch SW adjusts the voltage to the torque current command value Iq0 to zero and the voltage to the excitation current command value Id0 before the electromagnetic contactor CTT1 is turned on, that is, during voltage synchronous operation in which the generator stator voltage is synchronized with the system voltage. The output of the active power adjuster APR and the reactive power adjuster AQR are selected to be used after the electromagnetic contactor CTT1 is turned on.

  Here, the voltage regulator AVR will be described. The voltage regulator AVR inputs a value Vsref obtained by filtering the amplitude value Vgpk of the generator stator voltage Vg as a feedback value and a filter applied to the amplitude value of the system voltage Vs, and the amplitude value of the generator stator voltage Vg. The excitation current command value Id1 is output to the switch SW so that the deviation of the command value becomes zero. Here, the voltage regulator AVR can be constituted by, for example, a proportional integration controller. This voltage regulator AVR is operated with the magnetic contactor CTT1 in an open state, so that the amplitude value of the stator voltage of the generator Gen matches the amplitude value of the system voltage. It has a function to calculate the excitation current command value that flows to the side.

  The three-phase two-phase coordinate converter 32dqtrs detects the d-axis current detection value Idr (excitation current component) and the q-axis current detection from the input current Ir and the phase THr of the rotor using the conversion equation shown in the equation (6). The value Iqr (torque current component) is calculated, and the d-axis current detection value Idr is output to the current regulator 4-ACR, and the q-axis current detection value Iqr is output to the current regulator 3-ACR.

  The current regulator 4-ACR adjusts the output d-axis voltage command value Vdr so that the deviation between the d-axis current command value Id1 or Id0 and the d-axis current detection value Idr is zero. Similarly, the current regulator 3-ACR adjusts the output q-axis voltage command value Vqr so that the deviation between the q-axis current command value Iq1 or Iq0 and the q-axis current detection value Iqr becomes zero. Here, the current regulator can be constituted by a proportional integrator, for example.

  The d-axis voltage command value Vdr and the q-axis voltage detection value Vqr are input to a two-phase / three-phase coordinate converter dq23trs, and the two-phase / three-phase coordinate converter dq23trs receives the phase signal THr and the input values. The voltage command values Vur, Vvr, and Vwr output from the converter dq23trs are calculated by the conversion formulas shown in (Expression 7) and (Expression 8), and output to the PWM calculator PWMr.

  The PWM calculator PWMr calculates a gate signal Pulse_inv for turning on / off m semiconductor elements constituting the power converter INV by a pulse width modulation method from input voltage commands Vur, Vvr, Vwr, and the power Output to converter INV.

  The synchronous controller SYNC has two functions. One is a function to calculate the voltage command value for adjusting the amplitude value of the stator voltage to the amplitude value of the system voltage, and the second is to match the phase of the stator voltage before connection to the system to the phase of the system voltage. This is a function for calculating the phase correction value LTH.

  First, amplitude synchronization, which is the first function, will be described. In order to synchronize the voltage amplitude, an amplitude value Vspk of the system voltage is calculated from the square root of the square sum of Vα and Vβ, and a ripple is removed from the calculated amplitude value by a first-order lag filter or the like. Used as the command value Vsref. Similarly, the stator voltage Vgpk is also obtained from the α component and the β component, and is used for the feedback value Vgpk of the voltage regulator and for the amplitude synchronization determination. In the amplitude synchronization determination, the voltage command value Vsref and the voltage amplitude Vgpk are compared, and it is determined that the amplitude is synchronized when the difference is within a predetermined range.

  Next, the second function, phase synchronization, will be described. The phase synchronization function calculates the phase difference in order to match the phase of the system voltage and the phase of the stator voltage. If this phase difference is output as it is as the phase correction value LTH, the phase of the stator voltage of the generator changes abruptly. Therefore, an integrator with a limiter is inserted into the phase difference, and the output of the integrator is output as the phase correction value LTH. The phase correction value LTH is added to or subtracted from the rotational phase RTH to obtain the rotational phase TH.

  Here, the excitation phase THr is obtained by subtracting the rotation phase TH from the system voltage phase THs as described above, and is called a so-called slip frequency. Therefore, when the power converter INV is excited with the phase of the phase signal THr, the stator angular frequency ω1 matches the angular frequency ω0 of the system voltage (ω0 = ω1), and the phase also matches the phase correction value LTH.

  The synchronization controller SYNC sends a synchronization signal SYN to the system controller SYS when the phase matches the voltage. When the system controller SYS receives the synchronization signal SYN, the system controller SYS outputs signals Sg0 and Sg1 for operating the switch SW and the magnetic contactor CTT1. When the phase differences are substantially coincident and the synchronization determination flag SYN is output, the system controller SYS sends a control switching signal Sg0 to the switch SW and outputs a close command to the electromagnetic contactor CTT1.

  Next, the rectifier REC when a system disturbance occurs will be described. When the system voltage decreases, the current increases by ΔI due to the voltage difference ΔV between the induced voltage and the system voltage. At this time, if the turn ratio of the secondary excitation generator is a, the current of ΔI / a increases in the secondary winding. When the current of ΔI / a is large, an excessive current flows through the secondary winding.

  Since the power converter and the rectifier REC are connected to the secondary side via the reactors Lr and Lx, respectively, the current Ic flowing through Lr and the current Ix flowing through Lx are expressed by the following equation (9): (10) is divided by the ratio of the impedances ZLr and ZLx of the reactors Lr and Lx. The excessive current due to the disturbance at this time is caused by the DC component and the negative phase component of the accident current flowing on the primary side (stator), and appears as an AC current on the winding side. Therefore, the reactors Lr and Lx The impedances of the secondary power converter and the rectifier REC can be made different. Here, if the impedance ZLx of the reactor Lx on the rectifier side is the same as or smaller than the impedance ZLr of the reactor Lr on the power converter side, it is effective in protecting overcurrent. The current shunted to the rectifier REC side is preferably larger than the value obtained by subtracting the output current of the power converter from the rated output current of the generator Gen, and is 85% or less, more preferably 50% or less of the rated output current. Thus, the ratio of the impedance ZLx of the reactor Lx on the rectifier side and the impedance ZLr of the reactor Lr on the power converter side is set.

  The current thus shunted charges the smoothing capacitor Cd and the capacitor Cx in the DC portion, and increases the DC voltage. When the DC voltage rises, the elements and capacitors constituting the rectifier and the power converter cause dielectric breakdown, so that the energy consuming apparatus LOD is operated when the DC voltage exceeds a predetermined value, for example, 110% of the normal time.

  In order to operate the energy consuming apparatus LOD to control the DC voltage to be equal to or lower than a predetermined value, the subtractor 304 detects the deviation between the second DC voltage command value Eref_0V and the detected value Edc. When the deviation is negative, that is, when the DC voltage is larger than the command value, the deviation is output, and when the deviation is positive, that is, when the DC voltage is smaller than the command value, the limiter LIM that makes the output zero is used. As input.

  The DC voltage regulator DCAVR2 calculates a command value DUTY for turning on / off the switching element so that the energy consuming device LOD is operated only when the DC voltage is larger than the command value, and the switching element is turned on by the command value. A pulse command value Pulse_LOD for turning on / off is output to the energy consuming apparatus LOD.

  The energy consuming apparatus LOD is configured by connecting a resistor R in series with a power semiconductor switching element, for example, and operates so that the power of the DC voltage is consumed by the resistor R while the switching element is on. By operating the energy consuming apparatus LOD in this way, the DC voltage is kept below a predetermined value.

  Further, the rectifier REC and the energy consuming device LOD are installed in parallel on the power converter side, and a terminal for connecting the DC portion of the rectifier REC to the DC output portion of the power converter, for example, the smoothing capacitor Cd is arranged. Thus, one or a plurality of rectifiers REC and energy consuming devices LOD can be arranged in a necessary capacity. In this case, in order to connect to the direct current portion with low impedance, it is preferable to connect using a bus bar.

  As described above, in this embodiment, the value of the reactor Lx is changed and the rectifier is connected to the rotor, and the direct current portion of the rectifier REC is connected to the direct current portion of the power converter, so that the overcurrent generated in the rotor Most of the current can flow to the rectifier side, and the current flowing into the power converter side can be reduced. Therefore, there is an effect of reducing the current capacity of the power converter. Moreover, since the overcurrent of a power converter can be suppressed in a present Example, it is not necessary to stop the gate signal of a power converter, and the driving | operation of a power converter can be continued.

  Further, in this embodiment, the energy consuming device LOD is installed on the direct current side of the rectifier, and is operated when the direct current voltage rises due to overcurrent, so that the device can be protected from the overvoltage of the direct current voltage. In addition, since the rectifier REC is installed in parallel, it is installed separately for systems that want to continue operation when an overcurrent occurs in a system fault or systems that want to quickly output power after operation. It can respond flexibly to configurations such as not installing it when it is not necessary.

It is explanatory drawing of the circuit structure of the electric power generating apparatus of Example 1. FIG. It is a control block diagram of the control apparatus of the electric power generating apparatus of Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Windmill, 102 ... Encoder, 201 ... Integrator, Gen ... Secondary excitation generator, CTT1, CTT2 ... Electromagnetic contactor, INV, CNV ... Power converter, REC ... Rectifier, LOD ... Energy consumption device, BR ... Circuit breaker, CTRL ... Control device.

Claims (12)

Secondary excitation power comprising an AC excitation power converter for exciting the secondary winding of the secondary excitation generator with the stator side connected to the power system, and a control device for the AC excitation power converter In the conversion device,
The AC excitation power converter includes a first power converter for excitation and a second power converter for interconnection, the DC side of the first power converter and the second power converter. Connected to the DC side of
The AC side of the first power converter is connected to the secondary winding of the secondary excitation generator via a first impedance;
The DC side is connected in parallel to the DC connection portion of the first power converter and the second power converter, and the AC side is connected to the secondary winding of the secondary excitation generator via a second impedance. A power conversion device for secondary excitation, comprising a rectifier.   2. The secondary excitation power converter according to claim 1, wherein the first impedance and the second impedance are reactors. 3.   2. The secondary excitation power converter according to claim 1, wherein the value of the first impedance is larger than the second impedance. 3.   2. The secondary excitation power converter according to claim 1, wherein the rectifier is a diode rectifier. 3.   2. The secondary excitation power converter according to claim 1, wherein an energy consuming means is connected to the DC side of the rectifier. In the secondary excitation power converter according to claim 5,
The said control apparatus controls the direct current | flow side voltage of the said rectifier to below predetermined value using the said energy consumption means, The power conversion apparatus for secondary excitation characterized by the above-mentioned. In the secondary excitation power converter according to claim 1,
The AC excitation power converter includes a terminal for connecting the AC side of the diode rectifier to the secondary winding of the secondary excitation generator via the second impedance, and the DC side of the first power converter. And a terminal for connecting the DC side of the diode rectifier to a DC portion where the DC side of the second power converter is connected. A secondary excitation generator having a stator side connected to the power system, an AC excitation power converter for exciting the secondary winding of the secondary excitation generator, and a control device for the AC excitation power converter; In the secondary excitation power generator with
The AC excitation power converter includes a first power converter for excitation and a second power converter for interconnection, the DC side of the first power converter and the second power converter. Connected to the DC side of
The AC side of the first power converter is connected to the secondary winding of the secondary excitation generator via a first reactor,
The direct current side is connected in parallel to the direct current connection portion of the first power converter and the second power converter, and the alternating current side is connected to the secondary winding of the secondary excitation generator via a second reactor. With a rectifier,
The secondary excitation power generator characterized by the impedance of said 1st reactor being larger than the impedance of said 2nd reactor.   The secondary excitation power generator according to claim 8, wherein the rectifier is a diode rectifier. In the secondary excitation power generator according to claim 9,
The AC excitation power converter includes a terminal for connecting the AC side of the diode rectifier to the secondary winding of the secondary excitation generator via the second reactor, and the DC side of the first power converter. And a terminal for connecting the direct current side of the diode rectifier to a direct current portion connecting the direct current side of the second power converter.   9. The secondary excitation power generator according to claim 8, wherein an energy consuming means including a semiconductor switching element and a resistor is connected to the DC side of the rectifier. A secondary excitation generator comprising a rotor driven by a windmill and a stator connected to the power system, an AC excitation power converter for AC excitation of the secondary winding of the secondary excitation generator, and the AC In the secondary excitation wind power generator equipped with a control device for the excitation power converter,
The AC excitation power converter includes a first power converter for excitation and a second power converter for interconnection, the DC side of the first power converter and the second power converter. Connected to the DC side of
The AC side of the first power converter is connected to the secondary winding of the secondary excitation generator via a first reactor,
The direct current side is connected in parallel to the direct current connection portion of the first power converter and the second power converter, and the alternating current side is connected to the secondary winding of the secondary excitation generator via a second reactor. With a rectifier,
Connecting an energy consuming means comprising a semiconductor switching element and a resistor to the DC side of the rectifier;
The secondary excitation wind power generator characterized by the impedance of said 1st reactor being larger than the impedance of said 2nd reactor.

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