Black start device and method for wind turbine generator sets and wind turbine generator sets

Abstract

This disclosure provides a black-start device, method, and wind turbine generator set for wind power generation, belonging to the field of wind power technology. The black-start device includes a first power converter and an energy storage device. The energy storage device is connected to the DC bus in the converter of the wind turbine generator set and is connected to a first load of the wind turbine generator set through the first power converter. The grid-side inverter of the wind turbine generator set is connected to a second load of the wind turbine generator set. The first load is a load that affects the starting of the converter, and the second load is a load that does not affect the starting of the converter. Using the black-start device, method, and wind turbine generator set provided in this disclosure, black-starting of the wind turbine generator set can be achieved, improving the sustainable operation capability of the generator set and ensuring equipment safety.

Description

Technical Field

[0001] This disclosure relates to the field of wind power generation technology, specifically to a black start device, method, and wind turbine generator set. Background Technology

[0002] With the development of wind power technology, wind turbine generators have become increasingly widely used. They are no longer limited to providing power to onshore loads but have gradually shifted to providing power to offshore loads. Currently, the operation of wind turbine generators typically relies on external power grids. However, in certain scenarios, the external power grid may be unable to supply power to the generators, such as during grid failures or when the external power grid is disconnected for safety reasons during typhoons at sea. This can lead to the shutdown of wind turbine generators, endangering their safety and reducing their ability to operate sustainably.

[0003] It is evident that wind turbine generators currently suffer from low sustainable operating capacity due to power outages in the external power grid. Summary of the Invention

[0004] The purpose of this application is to provide a black-start device, method, and wind turbine generator set to solve the problem of low sustainable operation capability of current wind turbine generator sets due to power outages from the external power grid.

[0005] The technical solution disclosed herein is as follows:

[0006] According to a first aspect of the embodiments of this application, a black start device for a wind turbine generator set is provided, comprising a first power converter and an energy storage device. The energy storage device is connected to the DC bus in the converter of the wind turbine generator set and connected to a first load of the wind turbine generator set through the first power converter. The grid-side inverter of the wind turbine generator set is connected to a second load of the wind turbine generator set. The first load is a load that affects the start-up of the converter, and the second load is a load that does not affect the start-up of the converter; wherein:

[0007] The energy storage device is used to supply power to the first load through the first power converter when the wind turbine generator is shut down.

[0008] The first load is used to start the grid-side inverter when the energy storage device supplies power, and then the grid-side inverter supplies power to the first load and the second load, thereby starting the wind turbine generator set.

[0009] In one embodiment, the black start device of the wind turbine generator also includes a second power converter, through which the energy storage device is connected to the DC bus in the converter.

[0010] In one embodiment, the energy storage device is a battery module and the second power converter is a DC / DC converter.

[0011] In one embodiment, the black start device of the wind turbine generator set further includes a rectifier, a first end of which is connected to one end of the energy storage device, a second end of which is connected to the grid-side inverter, a third end of which is connected to the low-voltage side of the transformer in sequence through the grid-side circuit breaker and the grid-side inverter, and a fourth end of which is connected to the first load through the first power converter.

[0012] In one embodiment, the rectifier includes a first diode rectifier bridge, a second diode rectifier bridge, and a third diode rectifier bridge. The input terminal of the first diode rectifier bridge serves as the first terminal of the rectifier, the input terminal of the second diode rectifier bridge serves as the second terminal of the rectifier, and the input terminal of the third diode rectifier bridge serves as the third terminal of the rectifier. The output terminals of the first diode rectifier bridge, the second diode rectifier bridge, and the third diode rectifier bridge are connected and serve as the fourth terminal of the rectifier.

[0013] The first power converter is a DC / AC converter.

[0014] In one embodiment, the black start device of the wind turbine generator set further includes a first switch and a second switch; the grid-side inverter is connected to the second load of the wind turbine generator set through the first switch, and is connected to the second load of the wind turbine generator set in sequence through the grid-side circuit breaker and the second switch.

[0015] In one embodiment, when the wind turbine is operating and the external power grid is down, the first switch is closed and the grid-side circuit breaker is turned on, and the second switch is turned off.

[0016] According to a second aspect of the embodiments of this application, a wind turbine generator set is also provided, including the black start device of the wind turbine generator set described above.

[0017] According to a third aspect of the embodiments of this application, a black start method for a wind turbine generator set is also provided, applied to the aforementioned black start device, the method comprising:

[0018] When the wind turbine generator is shut down, the energy storage device supplies power to the first load;

[0019] The grid-side inverter starts up;

[0020] The grid-side inverter supplies power to the first load and the second load, and the wind turbine generator starts.

[0021] In one embodiment, after the wind turbine is started, the energy storage device stops supplying power to the first load.

[0022] In one embodiment, after the wind turbine generator is started, if the output power on the DC bus is less than a first power threshold, the energy storage device supplies power to the DC bus; if the power on the DC bus is greater than the first power threshold, the DC bus supplies power to the energy storage device.

[0023] The technical solutions provided by the embodiments of this disclosure have at least the following beneficial effects:

[0024] In this embodiment, when the wind turbine generator is shut down, the energy storage device supplies power to the first load of the wind turbine generator through a first power converter, so that the first load supplies power to the converter and starts the grid-side inverter. Then, the grid-side inverter supplies power to the second load, thereby starting the wind turbine generator. Thus, through this embodiment, when the wind turbine generator is shut down, the black start device can supply power to the wind turbine generator and start it, thereby reducing the downtime of the wind turbine generator and improving the sustainable operation capability of the generator. In addition, the energy storage device is connected to the DC bus of the converter, so that the energy storage device can charge the wind turbine generator with the electrical energy generated after the wind turbine generator starts, so that there is no need to connect an external power source to charge the energy storage device, thereby realizing the black start of the wind turbine generator by the energy storage device.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure, and are not intended to unduly limit this disclosure.

[0027] Figure 1 This is a schematic diagram of the structure of a wind turbine generator set according to an exemplary embodiment;

[0028] Figure 2 This is a schematic flowchart illustrating a black start method for a wind turbine generator set according to an exemplary embodiment. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of this disclosure, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0030] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0031] Please see Figure 1 This is a schematic diagram of the structure of a black start device for a wind turbine generator set according to an exemplary embodiment. Figure 1 As shown, the black start device of the aforementioned wind turbine generator set includes a first power converter 11 and an energy storage device 12. The energy storage device 12 is connected to the DC bus in the converter 21 of the wind turbine generator set and is connected to the first load 22 of the wind turbine generator set through the first power converter 11. The grid-side inverter 23 of the wind turbine generator set is connected to the second load 24 of the wind turbine generator set. The first load 22 is a load that affects the start-up of the converter 21, and the second load 24 is a load that does not affect the start-up of the converter 21.

[0032] The energy storage device 12 is used to supply power to the first load 22 through the first power converter 11 when the wind turbine generator is shut down.

[0033] The first load 22 is used to start the grid-side inverter 23 of the converter 21 when the energy storage device 12 is powered, and then the grid-side inverter 23 supplies power to the first load 22 and the second load 24 to control the start of the wind turbine generator set.

[0034] Here, when the wind turbine generator is shut down, the energy storage device 12 supplies power to the first load 22 of the wind turbine generator through the first power converter 11, so that the first load 22 supplies power to the converter 21 and starts the grid-side inverter 23. Then, the grid-side inverter 23 supplies power to the second load 24, realizing the start-up of the wind turbine generator. Thus, through this embodiment of the present disclosure, when the wind turbine generator is shut down, the black start device can supply power to the wind turbine generator and start it, thereby reducing the downtime of the wind turbine generator and improving the sustainable operation capability of the generator. In addition, the energy storage device 12 is connected to the DC bus, so that the energy storage device 12 can be charged with the electrical energy generated after the wind turbine generator is started, so that there is no need to connect an external power source to charge the energy storage device 12, thereby realizing the black start of the wind turbine generator by the energy storage device 12.

[0035] In this embodiment, the wind turbine generator set may include a converter 21, a first load 22, a grid-side inverter 23, and a second load 24. The output terminal of the converter 21 is connected to the input terminal of the grid-side inverter 23; the output terminal of the grid-side inverter 23 is connected to the first load 22 and the second load 24, respectively. Of course, the wind turbine generator set may also include other components, which will not be described in detail here.

[0036] It should be noted that the converter 21 is used to convert the electrical energy output by the wind turbine into DC power. Specifically, the AC power can be an AC-DC (Alternating Current-Direct Current) converter. The grid-side inverter 23 is used to convert the DC power input by the converter 21 through the DC bus into AC power. Specifically, the grid-side inverter 23 can be a DC-AC (Direct Current-Alternating Current) converter.

[0037] The first load 22 is the load that affects the startup of the converter 21. That is, if the first load 22 receives power when the wind turbine 20 is shut down, such as the energy storage device 12 or the external power grid supplying power to the first load 22, the first load 22 can provide power for the startup of the converter 21. Specifically, the first load 22 may include critical loads such as the control system of the wind turbine generator set.

[0038] Furthermore, the aforementioned second load 24 is a load that does not affect the startup of the aforementioned converter 21, and in the event of an external power grid failure, the second load 24 can be powered by the AC power output from the converter 21. Specifically, the aforementioned second load 24 may include secondary loads such as centrifugal fans and water-cooled pumps.

[0039] In this embodiment of the disclosure, the black start device of the wind turbine generator set includes the first power converter 11 and the energy storage device 12. The energy storage device 12 is connected to the first load 22 of the wind turbine generator set through the first power converter 11, and the energy storage device 12 is connected to the DC bus of the converter 21 of the wind turbine generator set.

[0040] The first power converter 11 is used to convert the electrical energy supplied to the first load 22 so that the power input to the first load 22 meets the needs of the first load 22. For example, when the first load 22 is an AC load and the input of the first power converter 11 is DC, the first power converter 11 can be a DC / AC converter, which converts the input DC power into the AC power required by the first load 22 and boosts the voltage input to the first load 22, such as boosting it to 400V AC power.

[0041] In addition, the energy storage device 12 is used to supply power to the first load 22 through the first power converter 11 when the wind turbine generator is shut down. This allows the energy storage device 12 to replace the external power grid in a timely manner to supply power to the first load 22 when the wind turbine generator is shut down, thereby enabling the wind turbine generator to start up.

[0042] In this embodiment of the disclosure, the energy storage device 12 is also connected to the DC bus of the converter 21 so that when the wind turbine generator set is started and running normally, the energy storage device 12 can be powered and charged by the DC power output from the DC bus, so that the energy storage device 12 can provide power for the start-up of the wind turbine generator set, and the wind turbine generator set can also provide power to the energy storage device 12, so that the power generated during the start-up of the wind turbine generator set by the energy storage device 12 is self-generated and self-used, thereby realizing the black start of the wind turbine generator set.

[0043] The energy storage device 12 is powered by a DC bus for energy storage and charging. This can be done by checking whether the output power of the DC bus can meet the power requirements of the loads (including the first load 22 and the second load 24, etc.) connected to the output of the grid-side inverter 23.

[0044] Specifically, after the wind turbine generator is started, if the output power on the DC bus is less than a first power threshold, the energy storage device 12 supplies power to the DC bus, wherein the first power threshold is related to the power of the load connected to the output terminal of the grid-side inverter 23; if the power on the DC bus is greater than the first power threshold, the DC bus supplies power to the energy storage device 12.

[0045] Here, when the output power of the DC bus changes (such as when the wind force driving the wind turbine changes, causing a change in the output power of the DC bus), the black start device can prioritize meeting the power demand of the load connected to the output terminal of the grid-side inverter 23. Furthermore, when the output power of the DC bus is insufficient, the energy storage device 12 can also supplement the power of the DC bus to ensure the normal operation of the load connected to the output terminal of the grid-side inverter 23, thereby further improving the stability of the wind turbine generator set operation.

[0046] It should be noted that the first power threshold mentioned above is related to the power of the load connected to the output terminal of the grid-side inverter 23. This could mean that the first power threshold is the power of the load connected to the output terminal of the grid-side inverter 23, or that there is a proportional relationship between the first power threshold and the power of the load connected to the output terminal of the grid-side inverter 23, and so on.

[0047] In addition, the aforementioned first power threshold can be a preset value, or it can change according to the change in the load connected to the output terminal of the grid-side inverter 23 when the load connected to the output terminal of the grid-side inverter 23 changes, for example, the load increases or decreases.

[0048] In this embodiment of the disclosure, the energy storage device 12 is connected to the DC bus of the converter 21, which can be a direct connection of the energy storage device 12 to the DC bus; or, specifically, the black start device can also include a second power converter 13, through which the energy storage device 12 is connected to the DC bus of the converter 21 of the wind turbine generator set. Here, the second power converter 13 can convert the electrical energy input to the energy storage device 12 from the DC bus, thereby protecting the energy storage device 12 and improving the stability of the black start device.

[0049] The second power converter 13 can be used to convert the electrical energy input from the DC bus to the energy storage device 12 so that the electrical energy input from the wind turbine generator to the energy storage device 12 meets the energy storage and charging requirements of the energy storage device 12. Specifically, the energy storage device 12 can be a battery module and the second power converter 13 can be a DC / DC converter. Here, the DC / DC converter can output the voltage required by the battery module to realize the normal energy storage and charging of the battery module.

[0050] In this embodiment of the application, the energy storage device 12 can be connected to the first load 22 through the first power converter 11, or the energy storage device 12 can be directly connected to the first power converter 11, and the first power converter 11 can convert the electrical energy output by the energy storage device 12 and output it to the first load 22.

[0051] Alternatively, to ensure the stable operation of the first load 22, the electrical energy input from the energy storage device 12 to the first power converter 11 can be processed. Specifically, the black start device can also include a rectifier 14. The first end of the rectifier 14 is connected to one end of the energy storage device 12, the second end of the rectifier 14 is connected to the grid-side inverter 23, the third end of the rectifier 14 is connected to the low-voltage side of the transformer 21 in sequence through the grid-side circuit breaker Q1 and the grid-side inverter 23, and the fourth end of the rectifier 14 is connected to the first load 22 of the wind turbine generator set through the first power converter 11.

[0052] Here, the energy storage device 12, the grid-side inverter 23, and the external power grid are respectively connected to the first power converter 11 through the rectifier 14. The rectifier 14 can rectify the electrical energy input to the first power converter 11 from the energy storage device 12, the grid-side inverter 23, and the external power grid, thereby improving the stability of the electrical energy input to the first power converter 11 and thus improving the operational stability of the first load 22.

[0053] It should be noted that the grid-side circuit breaker Q1 is located between the grid-side inverter 23 and the external power grid. When the wind turbine is running, the grid-side circuit breaker Q1 is used to control the electrical energy generated by the wind turbine to be fed into the external power grid. That is, when the wind turbine is running, the grid-side circuit breaker Q1 is closed, so that the current output by the grid-side inverter 23 is input to the external power grid. When the external power grid is disconnected and the wind turbine is stopped, the grid-side circuit breaker Q1 can be opened so that during the process of the energy storage device 12 supplying power to the first load 22 to start the wind turbine, the grid-side inverter 23 is controlled to output electrical energy only to the second load 24.

[0054] Alternatively, specifically, when the wind turbine is running and the external power grid is down, the first switch S1 is closed and the grid-side circuit breaker Q1 is turned on, and the second switch S2 is turned off. Thus, when the wind turbine is running and the external power grid is down, by closing the first switch S1 and turning on the grid-side circuit breaker Q1, not only can the grid-side inverter 23 supply power to its connected load, but it can also supply power to other wind turbines in the wind farm with the electrical energy generated by the wind turbine, thereby enabling the startup of other wind turbines when the external power grid is down.

[0055] In addition, the aforementioned energy storage device 12, grid-side inverter 23 and external power grid are respectively connected to the first power converter 11 through rectifier device 14. During the operation of the first load 22, only one of the energy storage device 12, grid-side inverter 23 and external power grid is required to provide power.

[0056] Therefore, in order to enable the energy storage device 12, the grid-side inverter 23 and the external power grid to provide power to the first load 22 respectively, the aforementioned black start device may also be equipped with a control unit, which can be used to connect the energy storage device 12, the grid-side inverter 23 and the external power grid to the first power converter 11 respectively.

[0057] For example, switches can be installed between the energy storage device 12, the grid-side inverter 23, and the external power grid and the first power converter 11, respectively. When the switch between the energy storage device 12 and the first power converter 11 is closed, and the switches between the grid-side inverter 23 and the external power grid and the first power converter 11 are both open, the energy storage device 12 provides power to the first load 22; when the switch between the grid-side inverter 23 and the first power converter 11 is closed, and the switches between the energy storage device 12 and the external power grid and the first power converter 11 are both open, the grid-side inverter 23 provides power to the first load 22; when the switch between the external power grid and the first power converter 11 is closed, and the switches between the energy storage device 12 and the grid-side inverter 23 and the first power converter 11 are both open, the external power grid provides power to the first load 22.

[0058] Alternatively, the rectifier 14 may include a first diode rectifier bridge 141, a second diode rectifier bridge 142, and a third diode rectifier bridge 143. The input terminal of the first diode rectifier bridge 141 serves as the first terminal of the rectifier 14, the input terminal of the second diode rectifier bridge 142 serves as the second terminal of the rectifier 14, and the input terminal of the third diode rectifier bridge 141 serves as the third terminal of the rectifier 14. The output terminals of the first diode rectifier bridge 141, the second diode rectifier bridge 142, and the third diode rectifier bridge 143 are connected and serve as the fourth terminal of the rectifier 14.

[0059] The first power converter 11 is a DC / AC converter.

[0060] Here, the aforementioned rectifier 14 includes a first diode rectifier bridge 141, a second diode rectifier bridge 142, and a third diode rectifier bridge 143. Based on the characteristics of the diode rectifier bridge 14, it is disconnected when the output voltage is higher than the input voltage and turned on when the output voltage is lower than the input voltage. This allows the highest voltage among the energy storage device 12, the grid-side inverter 23, and the external power grid output to be selected and input to the first power converter 11. This reduces the possibility of the first load 22 being affected by the input voltage and further improves the operational stability of the black start device.

[0061] For example, such as Figure 1As shown, when the external power grid is disconnected and the wind turbine is shut down, the input voltages of the third diode rectifier bridge 143 and the second diode rectifier bridge 142 are both zero, and the input voltage of the first diode rectifier bridge 141 is the output voltage of the battery. At this time, the first diode rectifier bridge 141 is turned on, and the third diode rectifier bridge 143 and the second diode rectifier bridge 142 are turned off, allowing the battery to supply power to the first load 22. When the external power grid is disconnected and the wind turbine is started and powered by the battery, if the output voltage of the second diode rectifier bridge 142 after rectification is higher than that of the first diode rectifier bridge 142, the wind turbine will be shut down. When the voltage input to diode rectifier bridge 141 is equal to the voltage input to diode rectifier bridge 141, then diode rectifier bridge 141 is disconnected and diode rectifier bridge 142 is turned on. At this time, grid-side inverter 23 can supply power to first load 22. When the external power grid is powered on, if the voltage output after rectification by third diode rectifier bridge 143 is higher than the voltage input to first diode rectifier bridge 141 and the voltage input to second diode rectifier bridge 142, then both first diode rectifier bridge 141 and second diode rectifier bridge 142 are disconnected and third diode rectifier bridge 143 is turned on. At this time, external power grid can supply power to first load 22.

[0062] It should be noted that, since diode rectifier bridges typically have three input terminals and three output terminals, the first diode rectifier bridge 141 connecting the energy storage device 12 and the first power converter 11 can be configured such that two input terminals of the first diode rectifier bridge 141 are connected to the positive and negative terminals of the energy storage device 12, respectively, while the other input terminal is left unconnected. The three output terminals of the first diode rectifier bridge 141 are connected to the three-phase AC input lines of the first power converter 11. The three input terminals of the second diode rectifier bridge 142 are connected to the three-phase AC output lines of the grid-side inverter 23, respectively, and the three output terminals of the second diode rectifier bridge 142 are connected to the three-phase AC input lines of the first power converter 11, respectively. The three input terminals of the third diode rectifier bridge 143 are connected to the three-phase AC output lines of the external power grid, respectively, and the three output terminals of the third diode rectifier bridge 143 are connected to the three-phase AC input lines of the first power converter 11, respectively.

[0063] In addition, the aforementioned black start device may also include a first switch S1 and a second switch S2; the grid-side inverter 23 is connected to the second load 24 of the wind turbine generator set through the first switch, and is connected to the second load 24 of the wind turbine generator set through the grid-side circuit breaker and the second switch in sequence.

[0064] Here, by controlling the closing of the first switch S1 and the second switch S2, the second load 24 can be powered through different transmission circuits during the start-up of the wind turbine generator set and during the normal operation of the wind turbine generator set. This avoids the output of the electrical energy generated by the grid-side inverter 23 to the external power grid during the start-up of the wind turbine generator set, thereby ensuring the normal start-up of the wind turbine generator set and further improving the sustainable operation capability of the wind turbine generator set.

[0065] For example, in the event of an external power grid outage and the wind turbine generator set shut down, the first switch S1 can be closed and the second switch S2 can be opened (at this time, the grid-side circuit breaker Q1 is open). Then, when the wind turbine generator set is started by the power supply of the energy storage device 12, the electrical energy output by the grid-side inverter 23 can supply power to the second load 24. When the wind turbine generator set is running normally, the first switch S1 can be opened and the second switch S2 can be closed (at this time, the grid-side circuit breaker Q1 is closed).

[0066] This disclosure also provides a wind turbine generator set, including the black start device for the wind turbine generator set described above.

[0067] Since the specific structure of the black start device of the wind turbine generator set has been described in the above embodiments of this disclosure, and other structures of the wind turbine generator set are well known to those skilled in the art, they will not be described in detail here.

[0068] Please see Figure 2 This disclosure also provides a black start method for wind turbine generators applied to the aforementioned black start device in this disclosure embodiment, combined with... Figure 1 and Figure 2 As shown, the method includes:

[0069] Step 201: When the wind turbine generator is shut down, the energy storage device 12 supplies power to the first load 22;

[0070] Step 202: The grid-side inverter 23 of the wind turbine generator set is started;

[0071] Step 203: The grid-side inverter 23 supplies power to the first load 22 and the second load 24, and the wind turbine generator set starts.

[0072] Here, when the wind turbine generator is shut down, the energy storage device 12 can supply power to the first load 22, which will start the grid-side inverter 23. Then, the power generated by the grid-side inverter 23 after it starts will supply power to the first load 22 and the second load 24, thereby starting the wind turbine generator. This enables the black start device to start the shut-down wind turbine generator and improves the sustainable operation capability of the wind turbine generator.

[0073] In step 201 above, when the wind power generation and unit shutdown occur, the energy storage device 12 supplies power to the first load 22. This can be achieved when the first switch S1 is closed and the second switch S2 is open, the first diode rectifier bridge 14 connecting the battery module (i.e., the energy storage device 12) and the first power converter 11 is turned on, while the second diode rectifier bridge 14 and the third diode rectifier bridge 14 are both turned off. The electrical energy provided by the battery module is converted by the first power converter 11 and then input to the first load 22.

[0074] In step 202 above, when the first load 22 is powered by the energy storage device 12, it can supply power to the converter 21. When the converter 21 is powered, it then starts the grid-side inverter 23 to convert the electrical energy provided by the converter 21.

[0075] In step 203 above, when the grid-side inverter 23 is started, the grid-side inverter 23 can input its output electrical energy into the first load 22 and the second load 24 to supply power to the first load 22 and the second load 24, thereby starting the wind turbine generator set.

[0076] In some embodiments of this disclosure, after the wind turbine generator is started, the energy storage device 12 stops supplying power to the first load 22.

[0077] Here, when the wind turbine is running, the energy storage device 12 stops supplying power to the first load 22, which can save the power of the energy storage device 12.

[0078] The aforementioned energy storage device 12 stops supplying power, which can be achieved after the wind turbine generator is started, by turning on the second diode rectifier bridge 14 between the grid-side inverter 23 and the first power converter 11, while turning off the second diode rectifier bridge 14 between the battery module and the first power converter 11, thereby supplying power to the first load 22 through the electrical energy output by the grid-side inverter 23.

[0079] In some embodiments of this disclosure, after the wind turbine generator is started, if the output power on the DC bus is less than a first power threshold, the energy storage device supplies power to the DC bus, wherein the first power threshold is related to the power of the load connected to the output terminal of the grid-side inverter; if the power on the DC bus is greater than the first power threshold, the DC bus supplies power to the energy storage device.

[0080] Here, when the output power of the DC bus changes (such as when the wind force driving the wind turbine changes, causing a change in the output power of the DC bus), the black start device can prioritize meeting the power demand of the load connected to the output terminal of the grid-side inverter 23. Furthermore, when the output power of the DC bus is insufficient, the energy storage device 12 can also supplement the power of the DC bus to ensure the normal operation of the load connected to the output terminal of the grid-side inverter 23, thereby further improving the stability of the wind turbine generator set operation.

[0081] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A black start device for a wind turbine generator system, characterized in that, The black start device comprises a first power converter and an energy storage device, the energy storage device is connected to a DC bus in a converter of the wind turbine generator system and connected to a first load of the wind turbine generator system through the first power converter, a grid-side inverter of the wind turbine generator system is connected to a second load of the wind turbine generator system, the first load is a load that affects starting of the converter, and the second load is a load that does not affect starting of the converter. The energy storage device is configured to supply power to the first load through the first power converter in a case where the wind turbine generator system is shut down. The first load is configured to start the grid-side inverter in a case where the energy storage device supplies power, and then the grid-side inverter supplies power to the first load and the second load, and the wind turbine generator system starts. The black start device further comprises a rectifier device, the rectifier device comprises a first diode rectifier bridge, a second diode rectifier bridge and a third diode rectifier bridge, an input end of the first diode rectifier bridge is connected to one end of the energy storage device as a first end of the rectifier device, an input end of the second diode rectifier bridge is connected to the grid-side inverter as a second end of the rectifier device, and an input end of the third diode rectifier bridge is connected to a low-voltage side of a transformer through a grid-side circuit breaker and the grid-side inverter as a third end of the rectifier device, and output ends of the first diode rectifier bridge, the second diode rectifier bridge and the third diode rectifier bridge are connected and connected to the first load through the first power converter as a fourth end of the rectifier device.

2. The black start device of claim 1, wherein, The black start device further comprises a second power converter, and the energy storage device is connected to the DC bus in the converter through the second power converter.

3. The starting device of claim 2, wherein The energy storage device is a battery module, and the second power converter is a DC / DC converter.

4. The starting device of claim 1, wherein The first power converter is a DC / AC converter.

5. A black start apparatus according to claim 4, characterised in that, The black start device further comprises a first switch and a second switch, the grid-side inverter is connected to the second load of the wind turbine generator system through the first switch, and is connected to the second load of the wind turbine generator system through the grid-side circuit breaker and the second switch in sequence.

6. The black start device of claim 5, wherein, In a case where the wind turbine generator system is running and an external power grid is powered off, the first switch is closed, the grid-side circuit breaker is turned on, and the second switch is turned off.

7. A wind power unit, characterized in that The black start device comprises the wind turbine generator system according to any one of claims 1-6.

8. A method of black start of a wind power plant, characterized in that, The method is applied to the black start device according to any one of claims 1-6, and the method comprises: The energy storage device supplies power to the first load in a case where the wind turbine generator system is shut down. The grid-side inverter starts. The grid-side inverter supplies power to the first load and the second load, and the wind turbine generator system starts.

9. The black start method of a wind power plant according to claim 8, characterized in that, After the wind turbine generator system starts and power reaches a preset threshold, the energy storage device stops supplying power to the first load.

10. The black start method of a wind power generating plant according to claim 9, characterized in that, After the wind turbine generator set is started, if the output power on the DC bus is less than a first power threshold, the energy storage device supplies power to the DC bus, wherein the first power threshold is associated with the power of a load connected to the output end of the grid-side inverter; if the power on the DC bus is greater than the first power threshold, the DC bus supplies power to the energy storage device.

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