CN112152215A - Filter capacitor operation control device and method of converter - Google Patents

Abstract

The present disclosure provides a filter capacitor operation control device and method for a converter, wherein the converter comprises a filter capacitor module, and the device comprises: the converter controller is used for respectively sending filter capacitor input control signals to the trigger module and the contactor module; the trigger module is used for detecting a voltage signal of a power grid and sending a trigger signal to the thyristor module according to the filter capacitor input control signal and the voltage signal; the thyristor module is used for conducting a thyristor in the thyristor module according to the trigger signal and the voltage signal so as to connect the power grid and the filter capacitor module through the conducted thyristor; and the contactor module is used for connecting the filter capacitor module with the power grid according to the filter capacitor input control signal, wherein when the contactor module is switched on, the power grid is connected with the filter capacitor module through the contactor module so as to bypass the thyristor module.

Description

Filter capacitor operation control device and method of converter

technical field

The present disclosure relates to the technical field of wind power generation, and more particularly, to a filter capacitor operation control device of a converter and a filter capacitor operation control method performed by the filter capacitor operation control device.

Background technique

With the development of wind power technology, full-power converters have been widely used in full-power wind turbines. The LCL filter is a grid-side filter for full-power converters. Its function is to filter out grid-side current harmonics. The power quality of the wind turbine can meet the requirements of the power grid and can be connected to the grid smoothly. The LCL filter is composed of box transformer leakage inductance, filter capacitor and reactor.

At present, the switching method of the grid-side filter capacitor of the wind power converter is adopted by the contactor switching method. As shown in Figure 1, 1 represents a circuit breaker, 2 represents a reactor, 3 represents a contactor, and 4 represents a filter capacitor module. When the filter capacitor is put into the power grid, the contactor switching method is adopted, and the contactor and filter capacitor will be impacted by dozens of times the rated current when they are put into the power grid. Therefore, the service life of the contactor and filter capacitor will be seriously affected, and may It will cause damage to the filter capacitor and adhesion of the main contacts of the contactor.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present disclosure provide a filter capacitor operation control device and method for a converter, at least solving the above technical problems and other technical problems not mentioned above, and providing the following beneficial effects.

An aspect of the present disclosure is to provide a filter capacitor operation control device of a converter, where the converter includes a filter capacitor module, and the device may include: a converter controller, configured to send the trigger module and the contactor to the trigger module and the contactor respectively. The module sends the filter capacitor input control signal; the trigger module is used to detect the voltage signal of the power grid, and sends the trigger signal to the thyristor module according to the filter capacitor input control signal and the voltage signal; the thyristor module is used to switch the thyristor module according to the trigger signal and voltage signal. The thyristor is turned on so that the power grid and the filter capacitor module are connected through the conductive thyristor; the contactor module is used to connect the filter capacitor module with the power grid according to the filter capacitor input control signal, wherein when the contactor module is turned on, the power grid is turned on. Connect with the filter capacitor module via the contactor module to bypass the thyristor module.

The thyristor module may include 6 thyristors, and the filter capacitor module includes a three-phase filter capacitor, wherein the first thyristor and the second thyristor form a control valve of the grid phase A for controlling the connection between the first filter capacitor and the grid phase A, and the third The trithyristor and the fourth thyristor form the control valve of phase B of the power grid to control the connection between the second filter capacitor and the phase B of the power grid, and the fifth thyristor and the sixth thyristor form the control valve of phase C of the power grid to control the third filter capacitor Connection to grid phase C.

The triggering module may send a triggering signal to the gate of each of the 6 thyristors based on the magnitude and phase of the grid voltage, wherein each thyristor in the thyristor module receives the triggering signal according to the corresponding gate and the The voltage signals at both ends of each thyristor are turned on so that the A-phase, B-phase and C-phase in the power grid are respectively connected with the corresponding filter capacitors in the filter capacitor module through the turned-on thyristors.

When it is detected that the magnitude of the grid voltage decreases to the low voltage standard, if the grid and the filter capacitor module are connected via the contactor module, in response to the filter capacitor input control signal, the thyristor in the thyristor module is turned on so that the grid and the filter capacitor module pass through The thyristor module that is turned on is connected; if the power grid and the filter capacitor module are not connected through the contactor module but are connected through the thyristor module, wait for the voltage signal to return to normal.

When the grid voltage returns to normal, the contactor module is turned on so that the grid and the filter capacitor module are connected through the conductive contactor module, and the thyristor module is disconnected.

The trigger module can send a trigger signal to the thyristor module again in response to the filter capacitor cut-out control signal sent by the converter controller, the thyristor module is turned on according to the trigger signal, and the contactor module is turned off in response to the filter capacitor cut-out control signal. On, the filter capacitor module is cut out from the grid after a preset time.

The thyristor module may disappear in response to the trigger signal, and the thyristors in the thyristor module are all turned off according to the filtered current zero-crossing point and the voltage signal from the trigger module.

Another aspect of the present disclosure is to provide a filter capacitor operation control method performed by a filter capacitor operation control device of a converter, wherein the converter includes a filter capacitor module, and the filter capacitor operation control device includes a converter control device. the trigger module, the thyristor module and the contactor module, wherein the method may include: detecting the voltage signal of the power grid by the trigger module; sending the filter capacitor input control signal to the trigger module and the contactor module by the converter controller ; The trigger module sends a trigger signal to the thyristor module according to the detected voltage signal and the filter capacitor input control signal; in response to the trigger signal, the thyristor module in the thyristor module is turned on according to the detected voltage signal to make the power grid and the converter The filter capacitor module in the device is connected through a conductive thyristor; in response to the input control signal of the filter capacitor, the contactor module connects the power grid and the filter capacitor module, wherein when the power grid and the filter capacitor module are connected via the conductive contactor module , the thyristor module is bypassed.

The thyristor module may include 6 thyristors, and the filter capacitor module includes a three-phase filter capacitor, wherein the first thyristor and the second thyristor form a control valve of the grid phase A for controlling the connection between the first filter capacitor and the grid phase A, and the third The trithyristor and the fourth thyristor form the control valve of phase B of the power grid to control the connection between the second filter capacitor and the phase B of the power grid, and the fifth thyristor and the sixth thyristor form the control valve of phase C of the power grid to control the third filter capacitor Connection to grid phase C.

The step of connecting the power grid to the filter capacitor module by the thyristor module according to the detected voltage signal may include: sending a trigger signal to the gate of each of the six thyristors by the trigger module based on the magnitude and phase of the power grid voltage, Each thyristor in the thyristor module is turned on according to the trigger signal received by the corresponding gate and the voltage signal at both ends of each thyristor, so that the A-phase, B-phase and C-phase in the power grid are respectively connected with the filter capacitor module. The corresponding filter capacitors are connected by conducting thyristors.

The method may further include: in response to the filter capacitor cut-out control signal sent by the converter controller, the trigger module sends a trigger signal to the thyristor module again, and the thyristor module is turned on according to the trigger signal; in response to the filter capacitor cut-out Control signal, disconnect the contactor module, and cut off the filter capacitor module from the grid after a preset time.

The method may further include: in response to the disappearance of the trigger signal, the thyristor module disconnects all the thyristors in the thyristor module according to the filtered current zero-cross point and the voltage signal from the trigger module.

Another aspect of the present disclosure is to provide a filter capacitor operation control method performed by a filter capacitor operation control device of a converter, wherein the converter includes a filter capacitor module, and the filter capacitor operation control device includes a converter control device. It is characterized in that, the method may include: detecting the voltage signal of the power grid by the triggering module; when the detected voltage signal meets the low voltage standard, determining by the triggering module whether the contactor has been The filter module puts the filter capacitor module into the power grid; when it is determined that the filter capacitor module is put into the power grid through the contactor module, in response to the filter capacitor input control signal, the thyristor in the thyristor module is turned on, so that the power grid and the filter capacitor module pass through the conduction. The thyristor module is connected.

The method may further include: when the detected voltage signal meets the low voltage standard and it is determined that the filter capacitor module has not been put into the power grid via the contactor module, determining, by the trigger module, whether to put the filter capacitor module into the power grid via the thyristor module, wherein when When it is determined that the filter capacitor module is put into the power grid through the thyristor module, wait for the voltage signal to return to normal. When it is determined that the filter capacitor module has not been put into the power grid through the thyristor module, turn off the converter.

The method may further include: after the grid voltage returns to normal, turning on the contactor module, so that the grid and the filter capacitor module are connected through the conductive contactor module, and the thyristor module is disconnected.

Another aspect of the present disclosure is to provide a computer including a readable medium storing a computer program, wherein the computer program includes instructions for executing the above method.

Based on the method and device described above, the switching characteristics of the thyristor are used to assist the contactor in switching the filter capacitor, so that the inrush current of the filter capacitor is small, and less external signals are required, thereby prolonging the service life of the contactor and the filter capacitor. At the same time, thyristor can also be used to pass the process of contactor disconnection during low voltage ride-through, and the control coil of the contactor can be stripped from the power supply of the UPS, thereby reducing the capacity of the AC uninterruptible power supply (UPS).

Description of drawings

These and/or other aspects and advantages of the present disclosure will become apparent, and be more readily understood, from the following description of embodiments, taken in conjunction with the accompanying drawings, wherein:

1 is a block diagram of a filter capacitor switching device in the prior art;

2 is a block diagram of a filter capacitor switching device of a converter according to an exemplary embodiment of the present disclosure;

FIG. 3 is a flowchart of a method for controlling a filter capacitor operation of a converter according to the first exemplary embodiment of the present disclosure;

FIG. 4 is a flowchart of a method for controlling a filter capacitor operation of a converter according to a second exemplary embodiment of the present disclosure;

FIG. 5 is a flowchart of a filter capacitor operation control method of a converter according to a third exemplary embodiment of the present disclosure.

Detailed ways

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of embodiments of the present disclosure as defined by the claims and their equivalents. Various specific details are included to aid in that understanding, but are to be regarded as exemplary only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present disclosure. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

In the present disclosure, terms including ordinal numbers such as "first," "second," etc. may be used to describe various elements, but these elements should not be construed as limited to these terms. These terms are only used to distinguish one element from other elements. For example, a first element could be termed a second element, and vice versa, without departing from the scope of the present disclosure.

Hereinafter, according to various embodiments of the present disclosure, the apparatus and method of the present disclosure will be described with reference to the accompanying drawings.

FIG. 2 is a block diagram of a filter capacitor operation control device of a converter according to an exemplary embodiment of the present disclosure.

Referring to FIG. 2 , a filter capacitor operation control device 200 of a converter may be included in a wind power converter (not shown). The filter capacitor operation control device 200 of the converter may include a converter controller 201 , a trigger module 202 , a thyristor module 203 , a contactor module 204 and a filter capacitor module 205 . Each module in the apparatus 200 according to the present disclosure may be implemented by one or more modules, and the name of the corresponding module may vary according to the type of the module. In various embodiments, some modules in apparatus 200 may be omitted, or additional modules may also be included. Furthermore, modules/elements according to various embodiments of the present disclosure may be combined to form a single entity, and thus may equivalently perform the functions of the corresponding elements prior to combination.

The converter controller 201 is a control module, which is mainly used for sending the control signal of filter capacitor input and the filter capacitor cut-out control signal. As shown in FIG. 2 , the first pin of the converter controller 201 is connected to the first pin of the trigger module 202 , the second pin of the converter controller 201 is connected to the second pin of the trigger module 202 , Thus, the 24V power supply is provided to the trigger module 202 via the converter controller 201 . The third pin of the converter controller 201 is connected to the third pin of the trigger module 202 and the seventh pin of the contactor module 204, and the fourth pin of the converter controller 201 is connected to the trigger module 202 The fourth pin is connected to the contactor module 204 and the eighth pin of the contactor module 204, so as to send control signals to the trigger module 202 and the contactor module 204 via the converter controller 201 respectively, that is, it is responsible for providing the filter capacitor module 205 in the In and out signals in the grid.

The trigger module 202 is a signal acquisition and output trigger signal module, which is mainly used to detect the voltage signal of the power grid and determine whether to send the trigger signal according to the filter capacitor input control signal and the voltage signal. As shown in FIG. 2 , the fifth pin of the trigger module 202 is connected to the first pin of the contactor module 204 (ie phase A of the power grid), and the sixth pin of the trigger module 202 is connected to the third pin of the contactor module 204 pin (ie, phase B of the power grid) is connected, and the seventh pin of the trigger module 202 is connected to the fifth pin of the contactor module 204 (ie, phase C of the power grid), so as to detect the voltage signal of the power grid through the trigger module 202 .

The thyristor module 203 may include 6 thyristors: the first thyristor T1, the second thyristor T2, the third thyristor T3, the fourth thyristor T4, the fifth thyristor T5, and the sixth thyristor T6, which are mainly used to connect the thyristor module according to the trigger signal and the voltage signal. The thyristor is turned on so that the power grid and the filter capacitor module 205 are connected through the thyristor that is turned on. Specifically, as shown in FIG. 2 , the eighth pin of the trigger module 202 is connected to the gate (G pole) of the thyristor T5 in the thyristor module 203 , and the ninth pin of the trigger module 202 is connected to the thyristor T6 in the thyristor module 203 The G pole of the trigger module 202 is connected to the G pole of the thyristor T3 in the thyristor module 203, and the eleventh pin of the trigger module 202 is connected to the G pole of the thyristor T4 in the thyristor module 203. The trigger module The twelfth pin of 202 is connected to the G pole of the thyristor T1 in the thyristor module 203, and the thirteenth pin of the trigger module 202 is connected to the G pole of the thyristor T2 in the thyristor module 203, so that the trigger module 202 is connected to the thyristor module. The G stage of each thyristor in 203 sends a trigger signal.

In addition, the anode (ie the A pole) of the thyristor T1 is connected to the first pin of the contactor module 204, the cathode (ie the K pole) of the thyristor T1 is connected to the second pin of the contactor module 204, and the A pole of the thyristor T2 is connected to the contactor module 204. The K pole of the thyristor T1 is connected, the K pole of the thyristor T2 is connected to the A pole of the thyristor T1, and the thyristor T1 and the thyristor group T2 form the control valve of the grid phase A. The A pole of the thyristor T3 is connected to the third pin of the contactor module 204, the K pole of the thyristor T3 is connected to the fourth pin of the contactor module 204, the A pole of the thyristor T4 is connected to the K pole of the thyristor T3, and the The K pole is connected to the A pole of the thyristor T3, and the thyristor T3 and the thyristor T4 form the control valve of the B phase of the grid. The A pole of the thyristor T5 is connected to the fifth pin of the contactor module 204, the K pole of the thyristor T5 is connected to the sixth pin of the contactor module 204, the A pole of the thyristor T6 is connected to the K pole of the thyristor T5, and the The K pole is connected to the A pole of the thyristor T5, and the thyristor T5 and the thyristor T6 form the control valve of the C phase of the grid.

In the present disclosure, the function of the thyristor module 203 is to form the control valve of phase A of the grid composed of thyristor T1 and thyristor T2, the control valve of phase B of the grid composed of thyristor T3 and thyristor T4, and the phase C of the grid composed of thyristor T5 and thyristor T6. In the case of the control valve of the thyristor, the thyristor is put into the grid according to the trigger signal of the G pole and the phase of the grid voltage by using the on and off characteristics of the thyristor, so as to ensure that no inrush current will be generated due to the large difference between the grid voltage and the initial voltage of the capacitor. In order to improve the life of the contactor and the life of the filter capacitor.

The filter capacitor module 205 may include three-phase filter capacitors, that is, a first filter capacitor C1, a second filter capacitor C2, and a third filter capacitor C3. The contactor module 204 connects the filter capacitor module 205 to the power grid according to the filter capacitor input control signal. As shown in FIG. 2 , the first pin of the contactor module 204 is connected to A of the power grid, the second pin of the contactor module 204 is connected to the first pin of the capacitor C1 in the filter capacitor module 205 , and the contactor module The third pin of 204 is connected to B of the power grid, the fourth pin of the contactor module 204 is connected to the first pin of the capacitor C2 in the filter capacitor module 205, and the fifth pin of the contactor module 204 is connected to the power grid. Phase C is connected, and the sixth pin of the contactor module 204 is connected to the first pin of the capacitor C3 in the filter capacitor module 205 . The A-phase, B-phase and C-phase of the power grid can be connected to the filter capacitors C1 , C2 and C3 respectively via the touch panel module 204 .

In addition, the second pins of the filter capacitors C1 , C2 and C3 in the filter capacitor module 205 are all connected to ground.

When the filter capacitor module 205 is put into the power grid, an LCL filter loop can be formed by the filter capacitor in the filter capacitor module 205, the inductance in the converter and the leakage inductance in the box transformer of the power grid. The LCL filter circuit can effectively filter out harmonics in high-power converters and inverters, so that the grid-connected equipment can meet the requirements of the power grid. It is currently the most widely used power grid filter circuit for new energy power generation systems.

The operation of each module in the filter capacitor operation control device 200 will be described in detail below with reference to FIG. 2 .

After the converter is powered on, the triggering module 202 detects the voltage signal of the grid in real time. When the converter controller 201 sends the filter capacitor input control signal to the trigger module 202 and the contactor module 204 respectively, the trigger module 202 sends the trigger signal to the thyristor module 203 according to the filter capacitor input control signal and the voltage signal. Specifically, in response to the filter capacitor input control signal being 1, the trigger module 202 collects the voltage signals of the three phases A, B, and C of the power grid through the fifth, sixth and seventh pins as the basis for triggering judgment, based on the magnitude of the power grid voltage And the phase sends a trigger signal to the G pole of each thyristor in the thyristor module 203, and each thyristor can be turned on according to the trigger signal received by the corresponding G pole and the voltage signal at both ends of each thyristor, so that the corresponding phase ( That is, the A-phase, B-phase and C-phase of the power grid are connected with the filter capacitor module 205 through the conducting thyristor. In this way, the characteristics of the thyristor can be used to assist the contactor module 204 in switching the filter capacitor, so as to avoid the shortening of the lifespan of the contactor and the filter capacitor due to a large inrush current when the filter capacitor is switched on.

In addition, in response to the filter capacitor input control signal being 1, the contactor in the contactor module 204 is closed, and the filter capacitor module 205 is connected to the grid via the contactor, thereby bypassing the thyristor module, thus reducing system losses. Next, the thyristor module 203 disappears in response to the trigger signal, and the thyristors in the thyristor module 203 are all turned off according to the filtered current zero-crossing point and the voltage signal from the trigger module 202 .

It should be noted that since it takes several tens of milliseconds for the contactor to close the contactor from receiving the filter capacitor input control signal, and the thyristor can act immediately after receiving the filter capacitor input control signal, therefore, the thyristor module 203 and the contactor module 204 can utilize the same control signal.

After the filter capacitor module 205 is put into the power grid, it forms an LCL filter loop with the internal inductance of the converter and the leakage inductance of the box transformer.

In addition, the converter controller 201 may also send a filter capacitor cut-out control signal to the contactor module 204 . In response to the filter capacitor cut-out control signal being 1, the trigger module 202 sends a trigger signal, and the contactor is disconnected, and the filter capacitor module 205 is put into the power grid through the thyristor module 203 . The triggering module 202 turns off the triggering signal after detecting the feedback signal that the contactor is disconnected. The thyristor is turned off when the filter current crosses the zero point, so that the filter capacitor module 205 is disconnected from the power grid.

According to an embodiment of the present disclosure, during the period when the grid and the filter capacitor module 205 are connected via the contactor module 204, when it is detected that the magnitude of the grid voltage decreases to a low voltage standard, in response to the filter capacitor input control signal being 1, the contactor module 204 is disconnected when the voltage is lost, and the thyristor in the thyristor module 203 is turned on, so that the grid and the filter capacitor module 205 are connected through the thyristor module 203 that is turned on. When the grid voltage returns to normal, the contactor module 204 is turned on so that the grid and the filter capacitor module 205 are connected through the conductive contactor module 204, and the thyristor module 203 is turned off.

FIG. 3 is a flowchart of a method for controlling a filter capacitor operation of a converter according to an exemplary embodiment of the present disclosure. The filter capacitor operation control method of FIG. 3 can be applied to the case where the power grid is in the normal operation mode.

In step S301, the converter is started.

After the converter is started, in step S302, the trigger module 202 in the filter capacitor operation control device 200 collects/detects the voltage signal of the power grid in real time.

In step S303, when the converter controller 201 sends the filter capacitor input control signal, that is, when the filter capacitor input control signal is 1, the process proceeds to step S304. Here, it should be noted that only when the sent filter capacitor input control signal is 1, the filter capacitor input control signal is used to input the filter capacitor into the power grid. Otherwise, the triggering module 202 continues to collect/detect the voltage signal of the power grid.

In step S304, the trigger module 202 sends a trigger signal to the G pole of the thyristor in the thyristor module 203 according to the collected voltage phase in response to receiving the filter capacitor input control signal.

In step S305, after the thyristor module 203 receives the trigger signal, the thyristor in the thyristor module 203 is turned on according to the trigger signal received by the G pole and the voltage at both ends of the thyristor, so that the A-phase and B-phase in the power grid are turned on by the turned-on thyristor. Phase and Phase C are respectively connected to the filter capacitors in the filter capacitor module 205 . In this way, firstly, the filter capacitor can be put into the grid via the thyristor module 203 . In the present disclosure, the thyristor is switched on according to the trigger signal of the G pole and the phase of the grid voltage by using the on and off characteristics of the thyristor, so as to ensure that no inrush current is generated due to the large difference between the grid voltage and the initial voltage of the capacitor.

In addition, in step S306, the contactor module 204 responds to receiving the filter capacitor input control signal, after a fixed time delay, the contactor in the contactor module 204 pulls in, that is, the contactor is turned on, through the conductive contactor Connect the grid to the filter capacitor module 205 . When the grid is connected to the filter capacitor module 205 via the contactor module 204, the thyristor module 203 is bypassed.

Since the contactor takes tens of milliseconds from receiving the filter capacitor input control signal to closing, and the thyristor can act immediately after receiving the control signal, therefore, when the thyristor module 203 and the contactor module 204 use the same control signal In the next step, the filter capacitor is first connected to the power grid through the conducting thyristor, and then the filter capacitor is connected to the power grid through the conducting contactor. At this time, the thyristor module 203 is bypassed, thereby reducing the loss of the system.

In step S307, in response to the contactor in the contactor module 204 being turned on, the trigger signal disappears, and in response to the disappearance of the trigger signal, due to the input of the contactor, the current is too small and the thyristor is cut out. All the thyristors in the thyristor module 203 are turned off by the thyristor module 203 according to the filtered current zero-cross point and the voltage signal from the trigger module 202 . When the trigger signal of the trigger module 202 disappears, the thyristor module 203 is completely turned off under the action of the zero-crossing current and the voltage across the thyristor.

In the case where the contactor module 204 connects the filter capacitor to the power grid, in step S308, when the converter controller 201 sends the filter capacitor cut-out control signal, the process proceeds to step S309, in response to the filter capacitor cut-out control signal being 1 , the triggering module 202 sends a triggering signal to the thyristor module 203 .

In step S310, in response to the trigger signal, the thyristor module 203 is turned on.

In step S311, in response to the filter capacitor cut-out control signal being 1, the contactor in the contactor module 204 is disconnected.

In step S312, the trigger turns off the trigger signal in response to the feedback signal that the contactor module 204 is disconnected.

In step S313, in response to the disappearance of the trigger signal, the thyristors are all turned off according to the zero-cross point of the filter current and the voltage signal, thereby cutting the filter capacitor out of the grid.

FIG. 4 is a flowchart of a method for controlling operation of a filter capacitor of a converter according to another exemplary embodiment of the present disclosure. The filter capacitor operation control method of FIG. 4 can be applied to the situation where low voltage ride through occurs during the time when the filter capacitor module 205 is put into the grid via the contactor module.

Referring to FIG. 4 , in step S401, when the converter operates normally, the triggering module 202 detects the voltage signal of the power grid in real time.

In step S402, when the detected voltage signal meets the low voltage standard, the process goes to step S403, otherwise the converter continues to operate normally. Here, since the contactor in the contactor module 204 cannot work normally due to the low voltage when the voltage signal of the power grid reaches the low voltage standard, the thyristor module 203 may need to be used to input the filter capacitor into the power grid.

In step S403, when the filter capacitor input control signal sent by the converter controller 201 is 1, the process proceeds to step S404. Here, it should be noted that only when the sent filter capacitor input control signal is 1, the filter capacitor input control signal is used to input the filter capacitor into the power grid.

When the filter capacitor input control signal sent by the converter controller 201 is 0, the filter capacitor module 205 is not input into the power grid.

In step S404, in response to the filter capacitor input control signal being 1, the trigger module 202 sends a trigger signal to the G pole of the thyristor in the thyristor module 203 according to the phase of the detected voltage.

In step S405, after the thyristor module 203 receives the trigger signal, the thyristor in the thyristor module 203 is turned on according to the trigger signal received by the G pole and the voltage at both ends of the thyristor, so that the A-phase, B Phase and Phase C are respectively connected to the filter capacitors in the filter capacitor module 205 .

In step S406, after the grid and the filter capacitor are connected via the thyristor module 203, the contactor is disconnected due to the loss of voltage in the control coil.

After the delay time of 2 s specified in the low voltage ride-through regulation, in step S407, the triggering module 202 continues to detect the voltage signal of the grid to determine whether the grid voltage returns to normal. When the detected voltage is a low voltage, the process proceeds to step S410. When the detected voltage returns to normal, the process proceeds to step S408.

In step S408, when the grid voltage returns to the normal state, if the converter controller 201 sends out a filter capacitor input control signal, the process goes to step S409, and the contactor control coil of the contactor module 204 is waited for the contactor control coil to be powered on, and the contactor is used. The module 204 connects the power grid to the filter capacitor, and then, in step S410, in response to the feedback signal that the contactor is turned on, the trigger signal sent by the trigger module 202 is turned off, that is, the trigger signal disappears.

In step S411, in response to the disappearance of the trigger signal, the thyristor module is disconnected at the current zero-crossing point, so that the filter capacitor is connected to the grid via the contactor module, thereby restoring the normal working state.

In step S407, if the voltage of the power grid does not return to normal, the process goes to step S410, and the trigger signal sent by the trigger module 202 is turned off. Accordingly, the thyristor is turned off. Here, it should be noted that in the case that the voltage does not return to normal, step S410 is only to turn off the trigger signal.

FIG. 5 is a flowchart of a filter capacitor operation control method of a converter according to a third exemplary embodiment of the present disclosure. The filter capacitor operation control method in FIG. 5 considers the situation that neither the contactor module 204 nor the thyristor module 203 is put into the grid and the filter capacitor module 205 .

Referring to FIG. 5 , in step S501 , when the converter operates normally, the triggering module 202 detects the voltage signal of the power grid in real time.

In step S502, when the detected voltage meets the low voltage standard, go to step S503, otherwise the converter continues to operate normally. Here, since the contactor in the contactor module 204 cannot work normally due to the low voltage when the voltage of the grid reaches the low voltage standard, it may be necessary to use the thyristor module 203 to put the filter capacitor module into the grid.

In step S503, it is determined whether the filter capacitor module 205 is put into the power grid via the contactor module 204 at the time of low voltage ride-through. Here, the trigger module 202 can determine whether to put the filter capacitor module 205 into the grid via the thyristor module according to the feedback signal of the contactor being turned off and turned on. When it is determined that the filter capacitor module 205 is put into the power grid via the contactor module 204, the process goes to step S504, and the converter controller 201 sends out the filter capacitor input control signal. In response to the filter capacitor input control signal being 1, the trigger module 202 A trigger signal is sent to the G pole of the thyristor in the thyristor module 203 according to the phase of the detected voltage.

In step S505, after the thyristor module 203 receives the trigger signal, the thyristor in the thyristor module 203 is turned on according to the trigger signal received by the G pole and the voltage at both ends of the thyristor, so that the A-phase, B-phase in the power grid are turned on through the turned-on thyristor. Phase and Phase C are respectively connected to the filter capacitors in the filter capacitor module 205 .

In step S506, after the grid and the filter capacitor module 205 are connected via the thyristor module 203, the contactor is disconnected due to the loss of voltage in the control coil.

After the delay time of 2 s specified in the low voltage ride-through regulation, in step S507, the trigger module 202 continues to detect the voltage signal of the grid to determine whether the grid voltage returns to normal. When the detected voltage is a low voltage, the process proceeds to step S510. When the detected voltage returns to normal, the process proceeds to step S508.

In step S508, after the grid voltage returns to a normal state, if the converter controller 201 sends a filter capacitor input control signal, the process proceeds to step S509, and the contactor control coil of the contactor module 204 is energized and closed, and the contactor is used. The module 204 connects the power grid to the filter capacitor, and then, in step S510, the trigger signal sent by the trigger module 202 is turned off, that is, the trigger signal disappears.

In step S511, in response to the disappearance of the trigger information, the thyristor module 203 is disconnected, so that the filter capacitor is connected to the power grid via the contactor module 204, thereby restoring the normal working state.

In step S507, if the voltage of the power grid does not return to normal, the process proceeds to step S510, and the trigger signal sent by the trigger module 202 is turned off. Accordingly, the thyristor is turned off. Here, it should be noted that in the case that the voltage does not return to normal, step S510 is only to turn off the trigger signal.

In addition, when it is determined in step S503 that the filter capacitor module 205 is not connected to the grid via the contactor module 204 , in step S512 , the trigger module 202 determines whether to connect the filter capacitor module 205 to the grid via the thyristor module 203 . Here, the triggering module 202 can determine whether to put the filter capacitor module 205 into the power grid via the thyristor module 203 according to the feedback signal of the thyristor being turned off and turned on.

When it is determined in step S512 that the filter capacitor module 205 is put into the power grid via the thyristor module 203, the process proceeds to step S507, and the trigger module 202 detects whether the voltage of the power grid returns to normal.

When it is determined in step S512 that the filter capacitor module 205 has not been put into the grid by the thyristor module 203, the converter is turned off, that is, the control process is ended.

According to the embodiments of the present disclosure, the characteristics of the thyristor are used to assist the contactor in switching the filter capacitor, so that the inrush current is small when the filter capacitor is switched on, which greatly improves the life of the contactor and the life of the filter capacitor, and By controlling the switching of the thyristor, the low voltage ride through can be successfully completed without using the UPS for the contactor.

The device and method described in the present disclosure can not only be applied to the operating wind turbines to prolong the life of the contactor and the filter capacitor, but also can be applied to the design of the new wind turbine, so that the filter capacitor and the contactor can meet the requirements of the wind turbine. Requirements for service life and maintenance.

Methods according to the present disclosure may be performed according to computer program instructions. Since these program instructions may be embodied in a computer, special purpose processor, or programmable or special purpose hardware, the instructions executed therein may facilitate performance of the functions described above. As understood by those skilled in the art, a computer, processor or programmable hardware includes a storage device that can store or receive software or computer code that, when accessed and executed by the computer, processor or hardware, implements methods described in this disclosure.

While the present disclosure has been shown and described with reference to its exemplary embodiments, those skilled in the art will appreciate that Various changes are made to its form and details.

Claims (16)

1. A filter capacitor operation control apparatus for a converter, said converter including a filter capacitor module, said apparatus comprising:

the converter controller is used for respectively sending filter capacitor input control signals to the trigger module and the contactor module;

the trigger module is used for detecting a voltage signal of a power grid and sending a trigger signal to the thyristor module according to the filter capacitor input control signal and the voltage signal;

the thyristor module is used for conducting a thyristor in the thyristor module according to the trigger signal and the voltage signal so as to connect the power grid and the filter capacitor module through the conducted thyristor;

a contactor module for connecting the filter capacitor module with the power grid according to the filter capacitor input control signal,

when the contactor module is conducted, the power grid is connected with the filter capacitor module through the contactor module to bypass the thyristor module.

2. The apparatus of claim 1, wherein the thyristor module comprises 6 thyristors and the filter capacitor module comprises a three-phase filter capacitor,

the first thyristor and the second thyristor form a control valve of a phase A of the power grid to control connection of the first filter capacitor and the phase A of the power grid, the third thyristor and the fourth thyristor form a control valve of a phase B of the power grid to control connection of the second filter capacitor and the phase B of the power grid, and the fifth thyristor and the sixth thyristor form a control valve of a phase C of the power grid to control connection of the third filter capacitor and the phase C of the power grid.

3. The apparatus of claim 2, wherein the trigger module sends a trigger signal to a gate of each of the 6 thyristors based on a magnitude and phase of a grid voltage,

each thyristor in the thyristor module is conducted according to the trigger signal received by the corresponding gate pole and the voltage signal at the two ends of each thyristor, so that the phase A, the phase B and the phase C in the power grid are respectively connected with the corresponding filter capacitor in the filter capacitor module through the conducted thyristors.

4. The apparatus of claim 1, wherein when a decrease in the magnitude of the grid voltage to a low voltage standard is detected, if the grid and filter capacitor modules are connected via the contactor module, in response to the filter capacitor enable control signal, a thyristor in the thyristor module is turned on so that the grid and filter capacitor modules are connected by the turned-on thyristor module; and if the power grid and the filter capacitor module are not connected through the contactor module but are connected through the thyristor module, waiting for the power grid voltage signal to be recovered to be normal.

5. The apparatus of claim 4, wherein when the grid voltage signal returns to normal, the contactor module is turned on so that the grid and the filter capacitor module are connected through the turned on contactor module, and the thyristor module is turned off.

6. The apparatus of claim 1, wherein the trigger module re-sends the trigger signal to the thyristor module in response to the filter capacitor cut-out control signal sent by the converter controller, the thyristor module being turned on according to the trigger signal, the contactor module being turned off in response to the filter capacitor cut-out control signal, the filter capacitor module being cut out from the grid after a preset time.

7. The apparatus of claim 1 or 6, wherein the thyristor module is responsive to the disappearance of the trigger signal, the thyristors in the thyristor module being fully turned off in response to the filtered zero crossing of the current and the voltage signal from the trigger module.

8. A filter capacitor work control method executed by a filter capacitor work control device of a converter, wherein the converter comprises a filter capacitor module, the filter capacitor work control device comprises a converter controller, a trigger module, a thyristor module and a contactor module, and the method comprises the following steps:

detecting a voltage signal of the power grid by a trigger module;

sending a filter capacitor input control signal to a trigger module and a contactor module by a converter controller;

the trigger module sends a trigger signal to the thyristor module according to the detected voltage signal and the filter capacitor input control signal;

responding to the trigger signal, conducting a thyristor in the thyristor module according to the detected voltage signal by the thyristor module so as to enable the filter capacitor module in the power grid and the converter to be connected through the conducted thyristor;

responding to the filter capacitor input control signal, connecting the power grid with the filter capacitor module by the contactor module,

when the power grid is connected with the filter capacitor module through the conducted contactor module, the thyristor module is bypassed.

9. The method of claim 8, wherein the thyristor module comprises 6 thyristors and the filter capacitor module comprises a three-phase filter capacitor,

the first thyristor and the second thyristor form a control valve of a phase A of the power grid to control connection of the first filter capacitor and the phase A of the power grid, the third thyristor and the fourth thyristor form a control valve of a phase B of the power grid to control connection of the second filter capacitor and the phase B of the power grid, and the fifth thyristor and the sixth thyristor form a control valve of a phase C of the power grid to control connection of the third filter capacitor and the phase C of the power grid.

10. The method of claim 9, wherein the step of connecting, by the thyristor module, the power grid to the filter capacitor module based on the detected voltage signal comprises:

sending, by the trigger module, a trigger signal to a gate of each of the 6 thyristors based on the magnitude and phase of the grid voltage,

and conducting each thyristor in the thyristor module according to the trigger signal received by the corresponding gate pole and the voltage signal at the two ends of each thyristor, so that the phase A, the phase B and the phase C in the power grid are respectively connected with the corresponding filter capacitor in the filter capacitor module through the conducted thyristors.

11. The method of claim 8, wherein the method further comprises:

responding to a filter capacitor switching-out control signal sent by the converter controller, sending a trigger signal to the thyristor module again by the trigger module, and conducting the thyristor module according to the trigger signal;

and responding to the filter capacitor switching-out control signal, disconnecting the contactor module, and switching out the filter capacitor module from the power grid after preset time.

12. The method of claim 8 or 11, wherein the method further comprises:

and in response to the disappearance of the trigger signal, the thyristors in the thyristor module are all disconnected by the thyristor module according to the filtering current zero crossing points and the voltage signals from the trigger module.

13. A filter capacitor work control method executed by a filter capacitor work control device of a converter, wherein the converter comprises a filter capacitor module, the filter capacitor work control device comprises a converter controller, a trigger module, a thyristor module and a contactor module, and the method comprises the following steps:

detecting a voltage signal of the power grid by a trigger module;

when the detected voltage signal meets the low voltage standard, the trigger module determines whether the filter capacitor module is switched into the power grid by the contactor module;

and when the filter capacitor module is determined to be switched into the power grid through the contactor module, responding to the filter capacitor switching control signal, switching on the thyristor in the thyristor module, and connecting the power grid and the filter capacitor module through the switched-on thyristor module.

14. The method of claim 13, wherein the method further comprises:

when the detected voltage signal meets a low voltage criterion and it is determined that the filter capacitor module is not to be launched into the grid via the contactor module, determining, by the trigger module, whether to launch the filter capacitor module into the grid via the thyristor module,

when the filter capacitor module is determined to be switched into the power grid through the thyristor module, the voltage signal is waited to be recovered to be normal, and when the filter capacitor module is determined not to be switched into the power grid through the thyristor module, the converter is closed.

15. The method of claim 13 or 14, wherein the method further comprises:

and when the voltage signal of the power grid is recovered to be normal, the contactor module is conducted, so that the power grid is connected with the filter capacitor module through the conducted contactor module, and the thyristor module is disconnected.

16. A computer arrangement comprising a readable medium having a computer program stored thereon, wherein the computer program comprises instructions for carrying out the method according to any one of claims 8 to 15.

Images