METHOD FOR CONTROLLING A LOW-FREQUENCY CURRENT DISCONTINUE AND A WIND GENERATOR SYSTEM

Abstract

A method for controlling a low-frequency current interrupter (5, 5U, 5V, 5W) for a wind generator system, comprising: a semiconductor switch (53, 53U, 53V, 53W) and a mechanical switch (54, 54U, 54V, 54W), wherein the semiconductor switch (53, 53U, 53V, 53W) is constructed such that a first and a second thyristor are connected antiparallel to each other, wherein the semiconductor switch (53, 53U, 53V, 53W) and the mechanical switch (54, 54U, 54V, 54W) are connected in parallel to each other and are connected in series with an AC path (2, 2U, 2V, 2W) which forms part of an AC circuit; an anomaly detector (6, 6U, 6V, 6W) that detects an anomaly of a current flowing through the AC path (2, 2U, 2V, 2W), wherein the current flowing through the AC path has a frequency of 10 to 20 Hz; and a circuit breaker control circuit that keeps the mechanical switch (54, 54U, 54V, 54W) constantly in the conducting state to allow a line current to flow to the AC path (2, 2U, 2V, 2W), brings the first and second thyristors into the conducting state by providing a gate signal to the first and second thyristors immediately before the current is switched off, causes the line current to switch through the AC path (2, 2U, 2V, 2W) so that it flows through the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W), by providing an opening command to the mechanical switch (54, 54U, 54V, 54W) when a current anomaly is detected, and switches off the gate signal to the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) after switching the line current, thereby interrupting an abnormal current flowing through the AC path (2, 2U, 2V, 2W).

Description

Technical field

[0001] The present invention relates to methods for controlling a low-frequency current interrupter, in particular for controlling a low-frequency current interrupter for a wind generator system or for use in a wind generator system, and to a wind generator system. State of the art

[0002] A conventional example of a wind generator system is one designed so that three-phase alternating current (AC) energy generated by a permanent magnet wind turbine is converted into direct current (DC) via a converter, to which, for example, an IGBT element in a bridge configuration is connected. This DC is then converted back into AC energy by an inverter, to which, for example, an IGBT element in a bridge configuration is connected, and supplied to an AC load.

[0003] In a system constructed as described above, it must be considered that a short-circuit fault can occur in an IGBT element that forms part of a converter, for several reasons. If an IGBT element experiences a short circuit, a short-circuit current continues to flow through a diode connected antiparallel to the IGBT element. However, there is currently no general-purpose current breaker capable of interrupting a fault current caused by a short-circuit fault, and therefore the development of a general-purpose current breaker is required.

[0004] A permanent magnet wind turbine cannot control the field current and must therefore interrupt any current flowing through a line between the stators. As long as this fault current is not interrupted, a properly functioning semiconductor component, such as an IGBT forming part of a converter's main circuit, can be damaged.

[0005] A synchronous power generator used in a permanent magnet wind turbine has a high internal impedance. A situation can arise where only a short-circuit current flows, at most approximately twice the normal current, even if an IGBT element causes a short circuit. Therefore, a current-limiting device such as a fuse cannot be used.

[0006] Traditionally, alternating current generated by a wind turbine and flowing through an AC path is, for example, a low-frequency current of 10 to 20 Hz. There is a need to develop a current interrupter that is cost-effective and has a simple design, capable of switching off this low-frequency current.

[0007] Currently, a DC circuit breaker is used in a wind generator system. One example of a DC circuit breaker is constructed such that a thyristor tube is connected in parallel with a bypass switch, such as a gas circuit breaker, as disclosed in patent specification 1.

[0008] Patent specification 2 relates to an arrangement for limiting the short-circuit current in 3-phase AC networks with one or more connected generators / motors, wherein at least one pair of series switches is arranged in each phase of the AC network leading to a generator / motor and a measuring device is provided for detecting a short-circuit event and blocking the series switches.

[0009] Patent specification 3 relates to a method for avoiding contact erosion in low-voltage circuit breakers, as well as a corresponding low-voltage circuit breaker.

[0010] Patent specification 4 relates to a circuit breaker for a distribution system comprising a non-self-extinguishing semiconductor switch and a current limiting element which is connected in series with the semiconductor switch to suppress a fault current.

[0011] Patent specification 5 relates to the field of circuit breakers, particularly for AC and DC networks and electrical installations and equipment in general. These circuit breakers, which are inserted into a circuit to be protected, contain a breaking element that interrupts the current flowing in the circuit to be protected under abnormal operating conditions, for example, in the event of a short circuit occurring in the circuit to be protected. Patent specification 1: JP H07 - 105 789 A Patent specification 2: EP 0 757 421 B1 Patent specification 3: EP 1 677 323 A1 Patent specification 4: DE 196 01 540 A1 Patent specification 5: DE 603 ​​03 773 T2 Disclosure of the invention (technical problem)

[0012] However, in a DC disconnect switch according to patent specification 1, both a thyristor tube and a gas disconnect switch, which form part of the circuit breaker, have large dimensions and are disadvantageous in terms of cost.

[0013] A circuit breaker that only has a thyristor switch will naturally cause a line loss due to the line.

[0014] The present invention therefore aims to provide a low-frequency current interrupter that is advantageous in terms of cost and causes low losses. (Solution to the problem)

[0015] The invention is set out in the attached claims. (Advantageous effects of the invention)

[0016] According to the invention, a low-frequency current interrupter is provided which has an overall simple design and small size, is advantageous in terms of cost and can reduce losses, since a current constantly flows through a mechanical switch during normal operation. Brief description of the drawings Fig. Figure 1 is a schematic block diagram showing the first embodiment according to a low-frequency current interrupter of the invention; Fig. Figure 2 is a time-series diagram to describe the functionality of Fig. 1; Fig. Figure 3 is a schematic block diagram showing the second embodiment of a low-frequency circuit breaker of the invention; and Fig. Figure 4 is a schematic block diagram showing the third embodiment of a low-frequency current interrupter of the invention. Description of embodiments

[0017] Embodiments of the invention are described below with reference to the drawings. First, the first embodiment is described with reference to a schematic block diagram in Fig. 1 and a time-series diagram in Fig. 2 described.

[0018] Fig. Figure 1 shows a wind generator system that converts alternating current (AC) energy generated by a wind turbine 1 into direct current (DC) energy via a power converter, such as a converter 3, through three-phase AC paths 2U, 2V, and 2W (generally denoted by 2), which form part of a three-phase AC circuit. The wind generator system further converts the DC energy into AC energy via an inverter 7 and supplies the AC energy to an AC load 8. A smoothing capacitor is denoted by 4 in the figure.

[0019] Low-frequency circuit breakers 5U, 5V, and 5W (generally designated 5) are connected in series with AC paths 2 for their respective phases. Furthermore, anomaly detectors 6U, 6V, and 6W (generally designated 6) are provided in series with the AC paths 2 for their respective phases. Anomalies in currents flowing through the AC paths 2 are detected by the anomaly detectors 6, and anomaly detection signals are fed into a circuit breaker control circuit 10, as shown in Fig. 2(a) is shown. When an anomaly detection signal is received by the circuit breaker control circuit 10, the low-frequency circuit breakers 5 perform a switching operation.

[0020] The low-frequency current breaker 5U is constructed such that a semiconductor switch 53U and a mechanical switch 54U are connected in parallel, and the semiconductor switch 53U is constructed such that a first thyristor 51U and a second thyristor 52U are connected in antiparallel. These elements are controlled by the current breaker control circuit 10, which is described below. Like the low-frequency current breaker 5U, the low-frequency current breaker 5V is constructed such that a semiconductor switch 53V and a mechanical switch 54V are connected in parallel, and the low-frequency current breaker 5W is constructed such that a semiconductor switch 53W and a mechanical switch 54W are connected in parallel.The 53V semiconductor switch is configured such that a first 51V thyristor and a second 52V thyristor are connected antiparallel to each other, and the 53W semiconductor switch is configured such that a first 51W thyristor and a second 52W thyristor are connected in parallel to each other. These elements are controlled by the current-interrupting control circuit 10, which is described below.

[0021] The circuit breaker control circuit 10 receives at least one of the anomaly detection signals originating from the anomaly detectors 6U, 6V, and 6W. When the anomaly detection signal is received, the circuit breaker control circuit 10 sends a gate signal to the thyristors 51 and 52 as shown in Fig. 2(d) and (e) provided. As in Fig. As shown in Figure 2(f), thyristors 51 and 52 switch on (become conductive). When thyristors 51 and 52 are switched on, the mechanical switches 54 receive an opening command from the circuit breaker control 10.

[0022] The wind generator system 1 comprises a permanent magnet rotor directly connected to a wind turbine 12 and a permanent magnet synchronous generator 11 consisting of a stator coil. In the converter 3, power converter elements 3U, 3V, 3W, 3X, 3Y, and 3Z are connected via a bridge circuit. Each power converter element is configured such that an arc-quenching element, such as an IGBT, and a diode are connected in antiparallel. Each power converter element can be switched on / off by a converter control circuit 9.

[0023] Now the operation of the low-frequency circuit breakers 5, constructed as described above, will be described with reference to Fig. 2 described. Fig. Figure 2(a) shows a current waveform of only one phase 2U of the AC paths 2, e.g., a current waveform flowing through AC path 2U when a power converter element 3U of converter 3 experiences a short circuit. When the current waveform rises to a value greater than a reference value, as in Fig. As shown in Figure 2(a), the anomaly detector 6U performs anomaly detection. A result of the anomaly detection is fed into the current-break control circuit 10. Then, the current-break control circuit 10 provides a gate signal for the thyristors 51 and 52, as shown in Figure 2(a). Fig. 2(d) and (e) are shown. Thyristors 51 and 52 switch on (become conductive), as shown in Fig. 2(f) is shown. When the thyristors 51 and 52 are switched on, the corresponding mechanical switch 54 is supplied with an opening command by the current-interrupting control circuit 10, and the mechanical switch 54 is thereby supplied with a Fig. 2(c) shown time limit opened.

[0024] When the mechanical switch 54 is opened, a line current that had previously flowed through the mechanical switches 54 is switched so that it flows through the thyristors 51 and 52. After the current is switched, the gate signal provided by the current-break control circuit 10, which is located in Fig. 2(a) The alternating current shown runs upwards until it reaches a zero crossing, and then thyristors 51 and 52 are switched off simultaneously. As a result, an abnormal current with a frequency of, for example, 10 to 20 Hz, which had been flowing through the alternating current paths, is switched off.

[0025] According to the first embodiment described above, the AC disconnect switches, each configured such that the mechanical switch 54 is connected in parallel with the semiconductor switch 53, which is configured such that the first and second thyristors are connected antiparallel to each other, are connected in series with the AC paths 2. Anomaly detectors are provided to detect when the current flow through the AC paths becomes abnormal. The current-interrupting control circuit causes the AC disconnect switches to interrupt the current when an anomaly is detected by the anomaly detectors. Using such a simple configuration, an abnormal low-frequency current can be blocked, which is advantageous in terms of cost reduction. Furthermore, according to this embodiment of the invention, a current flows continuously through each of the mechanical switches and causes essentially no loss.In contrast, a setup that uses only thyristor switches naturally causes losses, which are due to the electrical conduction.

[0026] In Fig. 1 and Fig. 2. In a normal state where the line current is not switched off, the thyristors 51 and 52 are not constantly switched on, but the thyristors 51 and 52 only need to be electrically conductive at least immediately before the current is switched off and can fulfill this requirement in a desirable way.

[0027] The preceding first embodiment was described in a case where AC paths form part of a three-phase AC circuit. However, the first embodiment is not limited to the three-phase AC circuit; the AC paths can also form part of any other type of AC circuit.

[0028] The preceding first embodiment was also described using an example applicable to a wind generator system. However, the first embodiment is not limited to this example, but can be applied to an alternating current circuit in which a low-frequency current flows in a different type of system.

[0029] Fig. Figure 3 is a schematic block diagram showing the second embodiment of the invention, which is described with reference to this figure. The Fig. The embodiment shown in Figure 3 is achieved by constructing only low-frequency current breakers 5U, 5V, and 5W of the first embodiment as follows. The low-frequency current breakers 5 all have the same construction and each comprises a semiconductor switch 53, configured such that a first and second thyristor 51 and 52 are connected to each other, and a mechanical switch 54. The mechanical switches 54 are connected in series with the low-frequency current breakers 5 and the AC paths 2. The semiconductor switches 53 are each connected between different paths of the AC paths 2. The mechanical switches 54 are constantly held in the conducting state to allow a current to flow to the AC paths 2. At least immediately before the current is switched off, a gate signal is provided to the first and second thyristor 51 and 52 to make the thyristors conduct.Opening the mechanical switches 54 switches the current flowing through the AC paths 2 to the thyristors 51 and 52. After the current has been switched, the gate signal for the thyristors 51 and 52 is turned off, thereby cutting off the current through the AC paths 2. The other configurations, not described here, are the same as those of the embodiment in Figure 1. Fig. 1.

[0030] Fig. Figure 4 is a schematic block diagram showing the third embodiment of the invention, which is described with reference to this figure. The Fig.The embodiment shown in Figure 4 is achieved by constructing only low-frequency current breakers 5U, 5V, and 5W of the first embodiment as follows. The low-frequency current breakers 5 all have the same construction and each comprises a semiconductor switch 53, formed by a first and second thyristor 51 and 52, and a first and second full-wave rectifier 55 and 56, which consist of semiconductor components, and a mechanical switch 54. The semiconductor switch 5 and the mechanical switch 54 are connected in parallel and in series with an AC path 2. In the semiconductor switch 5, a negative terminal of the first rectifier 55 and an anode of the first thyristor 51 are connected together, and a cathode of the first thyristor 51 is connected to a positive terminal of the second rectifier 56.A positive terminal of the first rectifier 55 and a cathode of the second rectifier 56 are connected together. The anode of the second thyristor 52 and a negative terminal of the second rectifier 56 are connected together.

[0031] In the configuration described above, the mechanical switches 54 are constantly held in the conducting state, allowing a conduction current to flow through the AC paths 2. At least immediately before the current is switched off, a gate signal is provided to the first and second thyristors 51 and 52 to make them conducting. Opening a mechanical switch 54 switches the conduction current for the AC paths 2 to the thyristors 51 and 52. After the current has switched, the gate signal for the thyristors 51 and 52 is switched off to interrupt the current.

[0032] The preceding embodiment was described in the case where the anomaly detectors 6U, 6V, and 6W are each provided for one of the AC paths 2U, 2V, and 2W, respectively. However, the embodiment is not limited to this configuration, but at least to the ability to detect a short-circuit condition and then generate an anomaly signal. For example, a method is available to directly detect a short-circuit condition of a component. In this case, upon receiving a signal indicating a short-circuit condition of a component, the mechanical switches 54 can be opened, and the firing of the thyristors 51 and 52 can begin.

[0033] In the preceding embodiment, the converter 3 converts alternating current (AC) energy into direct current (DC). Furthermore, the DC energy is converted back into AC energy by the inverter 7 and supplied to the AC load 8. However, the inverter 7 can also be omitted, and the DC energy output from the converter 3 can be supplied to a DC load (not shown). Reference symbol list 1 wind turbine 2U, 2V, 2W Three-phase AC path 2 Three-phase AC path 3 converters 3U, 3V, 3W power converter element 4 Smoothing capacitor 5U, 5V, 5W Low Frequency Circuit Breaker 5 Low-frequency circuit breakers 6U, 6V, 6W anomaly detector 6 Anomaly Detector 7 inverters 8 AC load 9 Converter control circuit 10 Current breaker control circuit 11 permanent magnet synchronous generator 12 wind turbines 51U, 51V, 51W First thyristor 52U, 52V, 52W Second Thyristor 52 Second thyristor 53U, 53V, 53W semiconductor switch 53 semiconductor switches 54U, 54V, 54W Mechanical Switch 54 Mechanical switch 55 First full-wave rectifier 56 Second full-wave rectifier

Claims

A method for controlling a low-frequency current interrupter (5, 5U, 5V, 5W) for a wind generator system, comprising: a semiconductor switch (53, 53U, 53V, 53W) and a mechanical switch (54, 54U, 54V, 54W), wherein the semiconductor switch (53, 53U, 53V, 53W) is configured such that a first and a second thyristor are connected antiparallel to each other, wherein the semiconductor switch (53, 53U, 53V, 53W) and the mechanical switch (54, 54U, 54V, 54W) are connected in parallel to each other and in series with an AC path (2, 2U, 2V, 2W) forming part of an AC circuit; an anomaly detector (6, 6U, 6V, 6W) which detects an anomaly of a current passed through the AC path (2, 2U, 2V, 2W) current flowing is detected, wherein the current flowing through the AC path has a frequency of 10 to 20 Hz;and a current-break control circuit that keeps the mechanical switch (54, 54U, 54V, 54W) constantly in the conducting state to allow a line current to flow to the AC path (2, 2U, 2V, 2W), brings the first and second thyristors into the conducting state by providing a gate signal to the first and second thyristors immediately before the current is turned off, switches the line current through the AC path (2, 2U, 2V, 2W) so that it flows through the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) by providing an opening command to the mechanical switch (54, 54U, 54V, 54W) when a current anomaly is detected, and sends the gate signal to the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) switches off after switching the line current, thereby interrupting an abnormal current flowing through the AC path (2, 2U, 2V, 2W). A method for controlling a low-frequency current interrupter (5, 5U, 5V, 5W) for a wind generator system, comprising: a semiconductor switch (53, 53U, 53V, 53W) and a mechanical switch (54, 54U, 54V, 54W), wherein the semiconductor switch (53, 53U, 53V, 53W) is configured such that a first and second thyristor (51, 51U, 51V, 51W and 52, 52U, 52V, 52W, respectively) are connected antiparallel to each other, wherein the mechanical switch (54, 54U, 54V, 54W) is connected in series with AC paths (2, 2U, 2V, 2W) forming part of an AC circuit, and the semiconductor switch (53, 53U, 53V, 53W) is connected between different paths of the AC paths (2, 2U, 2V, 2W); an anomaly detector (6, 6U, 6V, 6W) that detects an anomaly of a current flowing through the AC paths (2, 2U, 2V, 2W), wherein the current flowing through the AC paths has a frequency of 10 to 20 Hz;and a current-break control circuit that keeps the mechanical switch (54, 54U, 54V, 54W) constantly in the conducting state to allow a line current to flow to the AC paths (2, 2U, 2V, 2W), brings the first and second thyristors into the conducting state by providing a gate signal to the first and second thyristors immediately before the current is turned off, switches the line current through the AC paths (2, 2U, 2V, 2W) so that it flows through the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) by providing an opening command to the mechanical switch (54, 54U, 54V, 54W) when a current anomaly is detected, and sends the gate signal to the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) switches off after switching the line current, thereby interrupting an abnormal current flowing through the AC paths (2, 2U, 2V, 2W). A method for controlling a low-frequency current breaker (5, 5U, 5V, 5W) for use in a wind generator system that converts alternating current energy through a power converter (3) via an alternating current path (2, 2U, 2V, 2W) forming part of an alternating current circuit and supplying the converted electrical energy to a load, comprising: an anomaly detector (6, 6U, 6V, 6W) that detects a short circuit in a semiconductor device forming part of the power converter (3); a semiconductor switch (53, 53U, 53V, 53W) and a mechanical switch (54, 54U, 54V, 54W), wherein the semiconductor switch (53, 53U, 53V, 53W) is configured such that a first and a second thyristor are connected antiparallel to each other, wherein the semiconductor switch (53, 53U, 53V, 53W) and the mechanical switch (54, 54U, 54V, 54W) are connected in parallel and in series with the AC path (2, 2U, 2V,2W) are switched; and a current-break control circuit that keeps the mechanical switch (54, 54U, 54V, 54W) constantly in the conducting state to allow a line current to flow to the AC path (2, 2U, 2V, 2W), the current flowing through the AC path having a frequency of 10 to 20 Hz, brings the first and second thyristors into the conducting state by providing a gate signal to the first and second thyristors immediately before the current is cut off, switches the line current through the AC path (2, 2U, 2V, 2W) so that it flows through the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) by providing an opening command to the mechanical switch (54, 54U, 54V, 54W) when the anomaly detector (6, 6U, 6V, 6W) a short circuit of a semiconductor device forming part of the power converter (3) is detected, and the gate signal is sent to the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V,52W) after switching the line current, thereby interrupting an abnormal current flowing through the AC path (2, 2U, 2V, 2W). A method for controlling a low-frequency current interrupter (5, 5U, 5V, 5W) for use in a wind generator system that converts alternating current energy through a power converter (3) via alternating current paths (2, 2U, 2V, 2W) forming part of an alternating current circuit and supplying the converted electrical energy to a load, comprising: an anomaly detector (6, 6U, 6V, 6W) that detects a short circuit in a semiconductor device forming part of the power converter (3); a semiconductor switch (53, 53U, 53V, 53W) and a mechanical switch, wherein the semiconductor switch (53, 53U, 53V, 53W) is configured such that a first and second thyristor (51, 51U, 51V, 51W and 52, 52U, 52V, 52W, respectively) are connected antiparallel to each other, with the mechanical switch (54, 54U, 54V, 54W) being connected in series with the AC paths (2, 2U, 2V, 2W) and the semiconductor switch (53, 53U, 53V,53W) is connected between different paths of the AC paths (2, 2U, 2V, 2W); and a current-break control circuit that keeps the mechanical switch (54, 54U, 54V, 54W) constantly in the conducting state to allow a line current to flow to the AC paths (2, 2U, 2V, 2W), the current flowing through the AC paths having a frequency of 10 to 20 Hz, brings the first and second thyristors into the conducting state by providing a gate signal to the first and second thyristors immediately before the current is cut off, and switches the line current through the AC paths (2, 2U, 2V, 2W) so that it flows through the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) by providing an opening command to the mechanical switch (54, 54U, 54V, 54W) when the anomaly detector detects an anomaly. (6, 6U, 6V, 6W) a short circuit of a semiconductor component is detected, which forms part of the power converter (3),and switches off the gate signal to the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) after switching the line current, thereby interrupting an abnormal current flowing through the AC paths (2, 2U, 2V, 2W). A method for controlling a low-frequency current interrupter (5, 5U, 5V, 5W) for use in a wind generator system, which converts alternating current energy generated by a permanent magnet wind turbine through a power converter (3) consisting of an IGBT element, via an alternating current path (2, 2U, 2V, 2W) forming part of an alternating current circuit, and makes the converted electrical energy available to a load, comprising: an anomaly detector (6, 6U, 6V, 6W) that detects an anomaly of a current flowing through the alternating current path (2, 2U, 2V, 2W) or a short circuit of the IGBT element, wherein the current flowing through the alternating current path has a frequency of 10 to 20 Hz;a semiconductor switch (53, 53U, 53V, 53W) and a mechanical switch, wherein the semiconductor switch (53, 53U, 53V, 53W) is constructed such that a first and second thyristor (51, 51U, 51V, 51W and 52, 52U, 52V, 52W respectively) are connected antiparallel to each other, wherein the semiconductor switch (53, 53U, 53V, 53W) and the mechanical switch (54, 54U, 54V, 54W) are connected in parallel to each other and in series with the AC path (2, 2U, 2V, 2W);and a current-break control circuit that keeps the mechanical switch (54, 54U, 54V, 54W) constantly in the conducting state to allow a line current to flow to the AC path (2, 2U, 2V, 2W), brings the first and second thyristors into the conducting state by providing a gate signal to the first and second thyristors immediately before the current is cut off, switches the line current through the AC path (2, 2U, 2V, 2W) so that it flows through the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W), by providing an opening command to the mechanical switch (54, 54U, 54V, 54W) when the anomaly detector (6, 6U, 6V, 6W) detects a current anomaly or a short circuit of the The IGBT element is detected, and the gate signal to the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) is switched off after switching the line current, thereby interrupting an abnormal current flowing through the AC path (2, 2U, 2V, 2W). A method for controlling a low-frequency current interrupter (5, 5U, 5V, 5W) for use in a wind generator system, which converts alternating current energy generated by a permanent magnet wind turbine through a power converter (3) consisting of an IGBT element, via alternating current paths (2, 2U, 2V, 2W) forming part of an alternating current circuit, and provides the converted electrical energy to a load, comprising: an anomaly detector (6, 6U, 6V, 6W) that detects an anomaly in a current flowing through the alternating current paths (2, 2U, 2V, 2W) or a short circuit of the IGBT element; a semiconductor switch (53, 53U, 53V, 53W) and a mechanical switch (54, 54U, 54V, 54W), wherein the semiconductor switch (53, 53U, 53V, 53W) is constructed such that a first and second thyristor (51, 51U, 51V, 51W and 52, 52U, 52V, 52W respectively) are connected antiparallel to each other, with the mechanical switch (54, 54U, 54V,54W) is connected in series with the AC paths (2, 2U, 2V, 2W) and the semiconductor switch (53, 53U, 53V, 53W) is connected between different paths of the AC paths (2, 2U, 2V, 2W); and a current-break control circuit that keeps the mechanical switch (54, 54U, 54V, 54W) constantly in the conducting state to allow a line current to flow to the AC paths (2, 2U, 2V, 2W), the current flowing through the AC paths having a frequency of 10 to 20 Hz, brings the first and second thyristors into the conducting state by providing a gate signal to the first and second thyristors immediately before the current is cut off, and switches the line current through the AC paths (2, 2U, 2V, 2W) so that it flows through the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) by providing an opening command to the mechanical switch (54, 54U, 54V, 54W) when the anomaly detector detects an anomaly. (6, 6U, 6V,6W) an anomaly of a current or a short circuit of the IGBT element is detected, and the gate signal to the thyristors (51, 51U, 51V, 51W, 52, 52U, 52V, 52W) switches off after switching the line current, thereby interrupting an abnormal line current flowing through the AC paths (2, 2U, 2V, 2W). Wind generator system comprising a wind turbine (1) for generating alternating current energy, a power converter (3) for converting the alternating current energy into direct current energy via three-phase alternating current paths (2, 2U, 2V, 2W), characterized by a low-frequency current interrupter (5, 5U, 5V, 5W) controlled by a method according to one of claims 1 to 6.

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