Direct-current wind generating set and control method thereof

Abstract

The invention provides a direct-current wind generating set and a control method thereof. The direct-current wind generating set comprises a first converter, the first converter comprises a first rectifier and a first inverter, the input end of the first rectifier is connected to a generator of the direct-current wind generating set, the output end of the first rectifier is connected to the machine side end of the first inverter, and the grid side end of the first inverter is used for being electrically connected to a power grid; the second converter comprises a second rectifier, the input end of the second rectifier is connected to the generator, the second converter is connected with the first converter in parallel and does not comprise an inverter, and the output end of the second rectifier is connected to a load.

Description

Technical Field

[0001] The present application relates to the field of wind power, and more specifically, to a direct current wind turbine generator set and a control method thereof. Background Art

[0002] Large-megawatt wind turbines usually use two independent converters to handle the tasks of AC grid connection and DC output. Each converter is independently designed to meet its own power conversion needs. The flexibility of the current energy distribution scheme is limited and cannot adapt well to dynamic changes under different working conditions, especially for DC loads. The energy supply stability is insufficient.

[0003] Furthermore, it is difficult for existing solutions to optimize both AC grid-connected and DC output performance at the same time. When the wind turbine is not generating electricity, meeting the power consumption requirements of the inverter itself becomes a major challenge. Traditional topological structures cannot ensure stable power supply at this time, thus limiting the performance of DC wind turbines in a variety of application scenarios, especially in application scenarios that require efficient and stable DC output.

[0004] In addition, when the wind turbine is not in operation (for example, during maintenance), ensuring the power required for the continuous operation of the inverter is also a major problem. Existing solutions are difficult to meet the needs of the DC load side. Summary of the invention

[0005] In order to solve at least one of the above technical problems, the present disclosure provides a DC wind turbine generator set.

[0006] One of the purposes of the present disclosure is to provide a DC wind turbine generator set capable of stabilizing the high-power DC output of the converter.

[0007] One of the purposes of the present disclosure is to provide a DC wind turbine generator set that can be connected to the grid and can at least meet the power consumption demand of the wind turbine itself.

[0008] According to a first aspect of the present disclosure, a DC wind turbine generator set is provided, which includes: a first converter, including a first rectifier and a first inverter, the input end of the first rectifier is connected to the generator of the DC wind turbine generator set, the output end of the first rectifier is connected to the machine-side end of the first inverter, the grid-side end of the first inverter is used to be electrically connected to the power grid, a second converter, including a second rectifier, the input end of the second rectifier is connected to the generator, wherein the second converter is connected in parallel with the first converter and does not include an inverter, and the output end of the second rectifier is electrically connected to a load.

[0009] According to an embodiment of the present disclosure, the first inverter may be a bidirectional inverter, and a support capacitor and a chopper circuit may be connected between the machine side end of the first inverter and the output end of the first rectifier, and the chopper circuit may be connected in parallel with the support capacitor.

[0010] According to an embodiment of the present disclosure, the first converter and the second converter may be three-level converters, and the positive busbars, negative busbars, and neutral lines of the first converter and the second converter may be connected in parallel accordingly.

[0011] According to an embodiment of the present disclosure, the first inverter and the second rectifier may output electric energy to the outside at the same time, and the ratio of the output power of the second rectifier to the output power of the first inverter may be greater than 1.

[0012] According to an embodiment of the present disclosure, a ratio of the output power of the second rectifier to the output power of the first inverter may be greater than or equal to 5 and less than or equal to 50.

[0013] According to an embodiment of the present disclosure, the load may include a DC load of the first converter and a DC load of the second converter. The load may also include an external load of a DC wind turbine generator set. The output end of the second rectifier is connected to the external load via a DC-DC converter and / or a DC-AC converter. The DC wind turbine generator set may also include an energy storage system, which is connected to the output end of the first rectifier via a switch.

[0014] According to a second aspect of the present disclosure, a control method for a DC wind turbine generator set is provided. The DC wind turbine generator set is a DC wind turbine generator set as described above, and the control method includes: under power generation conditions, controlling a first inverter of a first converter to output a first power, and controlling a second rectifier to output a second power; under power consumption conditions, controlling the first inverter to obtain electric energy from a power grid, and supplying the obtained electric energy to a load via a machine-side input terminal of the first inverter and an output terminal of the second rectifier.

[0015] According to an embodiment of the present disclosure, the ratio of the first power to the second power may be less than 1 / 5.

[0016] According to an embodiment of the present disclosure, the control method may further include controlling the energy storage system to supply power to the load via the DC bus of the first converter and / or the second converter when the power grid fails and the generator of the wind turbine generator set does not generate electricity.

[0017] The DC wind turbine generator set according to the embodiments of the present disclosure can be applied in various application scenarios requiring high-power DC output. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. 4 is a diagram showing a topological structure of a DC wind turbine generator converter according to a first embodiment of the present disclosure.

[0019] Figure 2 FIG. 4 is a diagram showing a topological structure of a DC wind turbine generator converter according to a second embodiment of the present disclosure.

[0020] Figure 3 FIG. 4 is a diagram showing a topological structure of a DC wind turbine generator converter according to a third embodiment of the present disclosure.

[0021] Figure 4 FIG. 4 is a diagram showing a topological structure of a DC wind turbine generator converter according to a fourth embodiment of the present disclosure.

[0022] Figure 5 is a flow chart showing a control method of a DC wind turbine generator set according to the present disclosure.

[0023] Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings, and the same or similar elements will be indicated by the same or similar reference numerals throughout the accompanying drawings. DETAILED DESCRIPTION

[0024] The following detailed description is provided to help gain a comprehensive understanding of the methods, devices and / or systems described herein. However, the order of operations described herein is only an example and is not limited to those orders set forth herein, but may be equivalently replaced or changed except for operations that must occur or be performed in a specific order. In addition, for greater clarity and simplicity, the description of content known in the art will be omitted or simplified.

[0025] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which the present disclosure belongs after understanding the present disclosure. Unless explicitly defined as such herein, terms (such as those defined in general dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal manner.

[0026] Without special instructions, the same reference numerals generally refer to the same elements (e.g., components, steps, and methods). Reference numerals described in previous embodiments may be omitted if they appear again in later embodiments. In addition, the technical features described in different or the same embodiments may be combined in any manner, as long as the combined embodiments or technical solutions are complete and can solve the technical problems of the present application or achieve the technical effects described or not described in the present disclosure but can be determined based on the above complete technical solutions. The terms used in the present disclosure are explained below.

[0027] DC wind turbine: A wind turbine that converts wind energy into electrical energy. Its characteristic is that the generated electricity can be output in the form of direct current (DC), that is, it can convert the alternating current generated by the generator into direct current and can directly output direct current to meet the needs of various loads. DC wind turbines are generally suitable for application scenarios that require DC power, such as powering DC microgrids, battery energy storage systems or other DC loads.

[0028] One of the first converter and the second converter in the DC wind turbine generator set disclosed in the present invention is used for AC grid connection, and the other converter directly outputs DC power, thereby achieving grid connection and meeting the needs of DC loads. The converter disclosed in the present invention may have a converter topology structure obtained by modifying an existing wind turbine generator set, or may be an independently manufactured converter with a new topology structure. The following is a detailed description in conjunction with the embodiments of the present invention.

[0029] Figure 1 1 is a diagram showing a topological structure of a DC wind turbine generator converter according to a first embodiment of the present disclosure; Figure 2 1 is a diagram showing a topological structure of a DC wind turbine generator converter according to a second embodiment of the present disclosure; Figure 3 1 is a diagram showing a topological structure of a DC wind turbine generator converter according to a third embodiment of the present disclosure; Figure 4 FIG. 4 is a diagram showing a topological structure of a DC wind turbine generator converter according to a fourth embodiment of the present disclosure.

[0030] Reference Figures 1 to 4 According to an embodiment of the present disclosure, a DC wind turbine generator set includes a first converter and a second converter. The first converter and the second converter may be respectively arranged in converter cabinets, so the converter of the DC wind turbine generator set may have a first converter cabinet and a second converter cabinet. However, this is only an example, and the number of converter cabinets may be changed according to the capacity of the DC wind turbine generator, and the number of converters arranged in parallel may also be changed according to the capacity of the DC wind turbine generator set. Generally speaking, the larger the capacity, the greater the number of converters that can be connected in parallel.

[0031] The first converter includes a first rectifier and a first inverter, the input end of the first rectifier is connected to the generator of the DC wind turbine generator set, the output end of the first rectifier is connected to the machine side end of the first inverter, and the grid side end of the first inverter is used to be electrically connected to the power grid.

[0032] The first rectifier and the first inverter can achieve efficient energy exchange through the DC bus. The AC power generated by the generator of the DC wind turbine generator set enters the first rectifier after passing through the filter circuit and the reactor. The reactor and filter circuit equipped on the machine side are used to limit the current change rate, reduce current harmonics and stabilize the current output. The filter circuit can be formed by resistors and capacitors to smooth the current waveform and reduce high-order harmonic components.

[0033] The upper and lower bridge arms of each phase of the first rectifier may include six controllable switches (VT1, VT2, VT3, VT4, VT5 and VT6) and six diodes (i.e., freewheeling diodes D1, D2, D3, D4, D5 and D6 connected in anti-parallel with the controllable switches), that is, a three-phase bridge rectifier circuit may be formed as a whole, thereby converting AC power into DC power. Each controllable switch may be implemented by an IGBT, however, this is only an example, and other switching power devices such as MOSFET may also be used for implementation. These switching power devices may be turned on or off according to a control signal, thereby adjusting the direction and magnitude of the current, realizing the conversion from AC to DC, and ensuring that the voltage output to the DC bus is stable and smooth.

[0034] Reference Figures 1 to 4 The three-phase alternating current generated by the generator is connected to nodes A, B, and C of the first rectifier, respectively, corresponding to the three phase input terminals of the three-phase alternating current power supply. Node A corresponds to the A-phase input terminal of the three-phase alternating current, connected to the first phase of the three-phase alternating current provided by the generator, node B corresponds to the B-phase input terminal of the three-phase alternating current, connected to the second phase of the three-phase alternating current, and node C corresponds to the C-phase input terminal of the three-phase alternating current, connected to the third phase of the three-phase alternating current.

[0035] Reference Figures 1 to 4 Support capacitors C1 and C2 are arranged between the first rectifier and the first inverter. The support capacitors C1 and C2 can provide a stable DC voltage during instantaneous power fluctuations. The support capacitors C1 and C2 can be connected in series with each other between the positive bus DC+ and the negative bus DC-. The neutral point N between the support capacitors C1 and C2 can be connected to the upper and lower bridge arms of the first rectifier through a controllable switch. For example, the center point D can be connected to the upper and lower bridge arms of each phase through a controllable switch VT5 and a controllable switch VT6, respectively.

[0036] Each phase in the first rectifier may have the same structure, and the structure and connection mode of the controllable switch and diode in the first inverter may be the same as those of the first rectifier, which will not be described in detail here. The structure of the second rectifier may also be the same as that of the first rectifier.

[0037] Reference Figure 1 and Figure 4, the first inverter can be a bidirectional inverter, and in addition to the support capacitors C1 and C2, a chopper circuit can be connected between the machine side end of the first inverter and the output end of the first rectifier, and the chopper circuit can be connected in parallel with the support capacitor and can be directly connected to the DC bus to serve as a braking unit. For example, the chopper circuit can be used to discharge instantaneous high electric energy under high-throughput conditions. The structure of the chopper circuit is not specifically limited. For example, the chopper circuit may include a first chopper circuit connected between the positive bus DC+ and the neutral point N and a second chopper circuit connected between the negative bus DC- and the neutral point N. Each of the first chopper circuit and the second chopper circuit may include a resistor and a controllable switch connected in series with each other. In addition, the resistor may also be connected in parallel with a diode. The presence of the support capacitor and the chopper circuit not only improves the dynamic response capability of the system, but also enhances its adaptability and stability under various working conditions, ensuring that the wind turbine generator set can operate continuously and stably in a complex and changeable environment.

[0038] In addition, refer to Figures 1 to 4 A current limiting resistor is also connected between the positive bus DC+ and the negative bus DC-. The current limiting resistor limits the current when the circuit is just started or the supporting capacitor is connected to a new circuit link to maintain the supporting capacitor and other related circuit components.

[0039] Unlike the first converter, the second converter includes a second rectifier but not an inverter. The connection of the machine side end of the second converter is similar to the connection of the machine side end of the first rectifier. The input end of the second rectifier is connected to the generator. For example, the second rectifier can be connected to the generator via a reactor and a filter circuit. In addition, the second converter can be connected in parallel with the first converter, and the output end of the second rectifier can be electrically connected to various loads. The loads here may include the load of the first converter (for example, a DC load) and the load of the second converter (for example, a DC load). The loads of the first converter and the second converter themselves may include a converter controller, a heat sink of a power module, an IGBT drive circuit, a protection and monitoring circuit, etc. In addition, the load here may also be a load outside the converter or a DC wind turbine.

[0040] Unlike the first converter, in addition to not including an inverter, the second converter also does not include a chopper circuit, a supporting capacitor, and various components for grid connection at the grid side. The second converter can retain the rectifier component, that is, it can include a second rectifier. Like the first converter, the second converter can also be a three-level converter. The second converter (that is, the second rectifier) ​​can be connected to various loads through a DC bus. As an example, the positive bus, negative bus, and neutral line of the first converter and the second converter can be connected in parallel accordingly.

[0041] Apart from Figures 1 to 4In addition to the three-level converter shown, the first converter and the second converter according to the embodiment of the present disclosure can also be a two-level converter, which does not have a neutral point and each phase includes two controllable switches (e.g., IGBT), one located in the upper bridge arm and the other located in the lower bridge arm. When one of the switches is turned on, the corresponding other switch must be turned off to avoid a short circuit in the DC bus. In a two-level system, each phase has only two possible states: positive voltage or negative voltage, which makes the control strategy relatively simple.

[0042] In addition, Figures 1 to 4 In addition to the three-level converter shown, the first converter and the second converter according to the embodiment of the present disclosure can also be other multi-level converters, such as five-level, seven-level, etc. These converters can generate more voltage levels, thereby obtaining an output waveform that is closer to a sine wave. In addition, the multi-level converter may have a cascaded H-bridge structure, and several low-power H-bridge modules are connected in series to form a high-power converter, which can not only provide better output waveform quality, but also enhance the reliability of the system. However, the present disclosure is not limited to this, and the first converter and the second converter of the present disclosure may have other structures.

[0043] As an example, when the second rectifier of the DC wind turbine generator set is connected to an external load, the output end of the second rectifier can be connected to the external load via a DC-DC converter and / or a DC-AC converter. The external load here can be a hydrogen production system, etc.

[0044] Reference Figure 2 The output end of the second converter or the second rectifier can be connected to a DC load via a DC / DC converter. As mentioned above, the DC load here can be the load of the wind turbine itself. In addition to the load of the converter itself, the load of the wind turbine itself can also include other loads in the wind turbine. In addition, the DC load can also include a load outside the wind turbine.

[0045] Reference Figure 3 The second converter or the output end of the second converter can be connected to an AC load via a DC / AC converter, where the AC load can be an AC load outside the wind turbine. Before connecting the AC load, the voltage level can be transformed by a transformer to adapt to different loads.

[0046] Reference Figure 4 , the second converter or the output end of the second converter can be connected to the energy storage system, as an example, the energy storage system can also be connected to the DC bus of the first converter. Although not shown, the energy storage system can be connected to the DC bus of the first converter or the second converter via a controllable switch.

[0047] The first converter of the present invention has various components and circuits required for grid connection, so the DC wind generator set of the present invention can have grid connection capability and can maintain the stability of the system, and the DC wind generator set of the present invention can also meet the needs of various loads.

[0048] It should be noted that although the DC wind turbine generator set disclosed in the present invention has the ability to be connected to the grid, under normal circumstances, it is preferred to mainly output DC power. For example, the first inverter and the second rectifier output power to the outside at the same time, and the ratio of the output power of the second rectifier to the output power of the first inverter is greater than 1. As an example, the ratio of the output power of the second rectifier to the output power of the first inverter is greater than or equal to 5 and less than or equal to 50. The ratio of the output power of the second rectifier to the output power of the first inverter can be 6, 7, 8, 9, 10...40. For example, taking a 5MW DC wind turbine generator set as an example, the first converter can output hundreds of kW of power, and the second converter can output thousands of kW of power. For example, the output power of the first converter can be 100kW, and the output power of the second converter can be 4.9MW. The output power of the first converter can be 200kW, and the output power of the second converter can be 4.8MW. In addition, the capacity of the DC wind turbine generator set can be 3MW, 4MW, 5MW, 6MW, 7MW, etc.

[0049] The control method of the DC wind turbine generator set disclosed in the present invention may be as follows: under power generation conditions, the first inverter of the first converter is controlled to output the first power, and the second rectifier is controlled to output the second power. For example, the first inverter of the first converter and the second rectifier of the second converter can be controlled to output power at the same time. Taking a 5MW DC wind turbine generator set as an example, the first converter can have a grid-connected capacity of 2.5MW at most, but under normal circumstances, the output power of the first inverter can be limited to several hundred kW, and the output power of the first inverter can be limited by adjusting the duty cycle of the power device or controllable switch of the first inverter. As described above, the first inverter is a bidirectional inverter. Under power consumption conditions or power extraction conditions, the first inverter can be controlled to obtain electric energy from the power grid, and the obtained electric energy is supplied to the load via the machine-side input end of the first inverter and the output end of the second rectifier. This can ensure that the wind turbine can obtain electric energy from the power grid to meet the needs of the load without generating electricity.

[0050] Figure 5 is a flow chart showing a control method of a DC wind turbine generator set according to an embodiment of the present disclosure.

[0051] The control method of the DC wind turbine generator set according to the embodiment of the present disclosure may include step S110 , step S120 , step S130 , and step S140 .

[0052] In step S110, it is determined whether the DC wind turbine generator set is in a power generation condition. Whether the wind turbine generator set is in a power generation condition can be determined by multiple indicators: when the wind force is strong enough, the wind wheel starts to rotate and drives the generator to operate. If it is detected that the speed of the generator exceeds the starting threshold (usually set to a lower speed to ensure that the wind force is sufficient to drive power generation), it indicates that the unit has entered the power generation condition; a comprehensive judgment can be made by monitoring the status of multiple key components. In one example, it can be determined whether the generator is in a power generation state based on the voltage and frequency at the output end of the generator. In one example, it can be determined whether the generator is in a power generation state based on the excitation current. In addition, it is also possible to determine whether the generator is in a power generation state by the DC bus voltage. A stable DC bus voltage that is within the expected range means that the generator delivers energy to the bus. As an example, it is also possible to determine whether the generator is in a power generation condition or a power generation state based on the setting or resetting of the corresponding power generation condition flag.

[0053] In step S120, in response to the DC wind turbine generator set being in a power generation condition, the first inverter of the first converter is controlled to output the first power, and the second rectifier is controlled to output the second power. Under normal circumstances, as described above, the first power may be much smaller than the second power, for example, the first power may be at most one-fifth of the second power. That is, the DC wind turbine generator set according to the present disclosure retains a relatively small grid-connected capability and mainly provides DC power.

[0054] As an example, the first converter can be ensured to output only a very small part of the electric energy to meet the possible small power grid connection by reducing the PWM duty cycle, reducing the DC bus voltage or limiting the current, while the second converter can undertake the main power conversion task and provide most of the required electric energy to the load in a highly efficient manner. As an example, a special power allocation algorithm can be designed to coordinate the power output ratio between the first converter and the second converter. The algorithm can dynamically adjust the working point of each converter according to the preset proportional relationship to ensure that the output power of the first converter is much less than the output power of the second converter. In addition, the operating status of the first converter and the second converter can be monitored in real time, and a rapid response can be made based on the feedback information to adapt to changes in load or grid conditions.

[0055] However, the above energy distribution method is only an example. In extreme cases, the first converter can provide at most half the capacity of the DC wind turbine. Taking a 5MW DC wind turbine as an example, when the power grid needs the DC wind turbine to participate in energy scheduling, or in order to maintain the stability of the power grid system, the first converter can output at most 2.5MW of power.

[0056] In step S130, in response to the DC wind generator set not being in a power generation condition, it is further determined whether the DC wind generator set is in a power consumption condition or a power extraction condition.

[0057] Whether the DC wind turbine generator set is powered from the power grid can be determined in the following manner. For example, whether the bidirectional inverter is powered from the power grid can be determined based on a control signal sent by a master control or energy management system. In addition, the DC wind turbine generator set is also determined to be in a power-taking condition based on the current and modulation state of the first inverter.

[0058] In step S140, in response to the DC wind turbine generator set being in a power-using or power-taking state, the first inverter is controlled to obtain electric energy from the power grid, and the obtained electric energy is supplied to the load via the machine-side input terminal of the first inverter and the output terminal of the second rectifier. Thus, the power supply capacity can be maintained when the generator is not generating electricity (for example, shutting down), thereby meeting the needs of the DC load.

[0059] In addition, as an example, the power output ratio between the two converters can be dynamically adjusted based on real-time monitored grid demand and current wind conditions. When the grid needs more power, the first converter is allowed to increase its output power up to half of the total system capacity.

[0060] For example, under another operating condition different from the normal power generation condition and the power extraction condition, the first inverter of the first converter can be controlled to output the first power, and the second rectifier can be controlled to output the second power. The first power and the second power can be the same or substantially the same. As an example, the first power and the second power can both be 2.5MW. That is to say, under this operating condition, the first power can no longer be much less than the second power, but close to the second power. As an example, the power balance between the first converter and the second converter can be automatically adjusted to ensure stable operation of the system even under high load conditions.

[0061] In one example, when the power grid fails and the DC wind turbine generator set does not generate electricity, the energy storage system can be used to supply power to each load. For example, when the power grid fails and the DC wind turbine generator does not generate electricity, the switch on the power supply path of the energy storage system can be controlled to close, so that the electric energy stored in the energy storage system is supplied to each load via the DC bus of the first converter and / or the second converter. In this way, the power supply capacity in extreme cases can be guaranteed.

[0062] Specifically, with the closing of the designated switch, the energy storage system is connected to the DC bus of the first converter and / or the second converter. At this time, the electric energy stored in the energy storage system can be transmitted to each load through the DC bus. In order to maximize the use of limited energy resources, each load can be prioritized according to its importance, and the available power can be reasonably allocated to ensure that the most important or most urgent equipment receives power support first. During the entire control process, the remaining power of the energy storage system, changes in load demand, and other factors that may affect power supply can be closely tracked, so that the output power of the energy storage system can be dynamically adjusted according to actual conditions to extend the power supply time and optimize energy utilization efficiency.

[0063] As an example, in order to prevent the energy storage system from being damaged due to over-discharge or being unable to resume normal charging, a minimum power threshold can be set for the energy storage system. When the energy storage system approaches this threshold, the system will reduce or stop the power supply to certain non-critical loads, retaining enough energy for the most critical applications. The state of the grid can be evaluated in real time, and once the grid fault is repaired or the wind conditions improve so that the wind turbines can resume generating electricity, the overall power supply situation can be evaluated again. If it is determined that normal power supply can be restored, the switches on the power supply path of the energy storage system can be gradually turned off, and the wind turbines or the grid can be allowed to take on the main power supply task again. This ensures a smooth transition without causing impact to the load or interrupting the power supply.

[0064] The energy storage system here can be a part of the DC wind turbine generator set, or it can be a component independent of the DC wind turbine generator set.

[0065] Each step of the above control method can be implemented by a corresponding software or hardware module or unit.

[0066] The above has been referred to Figures 1 to 5 A DC wind turbine generator set and a control method thereof according to an exemplary embodiment of the present disclosure are described. However, it should be understood that the units, modules, and systems shown in the accompanying drawings may be configured as software, hardware, firmware, or any combination of the above items to perform specific functions. For example, these systems and devices may correspond to dedicated integrated circuits, pure software codes, or modules that combine software and hardware. In addition, one or more functions implemented by these systems or devices may also be uniformly performed by components in physical entity devices (e.g., processors, clients, or servers, etc.).

[0067] For example, according to an exemplary embodiment of the present disclosure, a computer-readable storage medium storing instructions may be provided, wherein when the instructions are executed by at least one computing device, the at least one computing device is prompted to perform at least one of the above steps.

[0068] It should be noted that the control method according to the exemplary embodiment of the present disclosure may rely on the execution of a computer program or instructions to implement the corresponding functions, that is, each device corresponds to each step in the functional architecture of the computer program, so that the entire system is called through a special software package (e.g., lib library) to implement the corresponding functions.

[0069] On the other hand, when the system, unit, or module is implemented in software, firmware, middleware, or microcode, the program code or code segment for performing the corresponding operation may be stored in a computer-readable medium such as a storage medium, so that at least one processor or at least one computing device may perform the corresponding operation by reading and running the corresponding program code or code segment. In addition, the computer-readable medium or storage medium may cause the processor to execute the above-mentioned control method when the computer program is executed by the processor.

[0070] For example, according to an exemplary embodiment of the present disclosure, a computer device including a readable medium storing computer program instructions may be provided, wherein the instructions, when executed by at least one computing device, prompt the at least one computing device to perform at least one of the above steps.

[0071] According to an exemplary embodiment of the present disclosure, a converter controller may be provided, which may include a memory and a processor, wherein the memory stores instructions or programs, and when the instructions or programs are executed by the processor, the processor is prompted to execute the above-mentioned control method, for example, at least one of the various steps of the above-mentioned control method may be executed.

[0072] According to the embodiment of the present disclosure, the DC wind turbine generator set adopts a new converter topology solution, which can stabilize the high-power DC output of the converter.

[0073] The DC wind turbine generator set according to the embodiment of the present disclosure can be connected to the grid and meet its own power consumption demand.

Claims

1. A DC wind turbine generator set, characterized in that: include: The first converter includes a first rectifier and a first inverter, wherein an input end of the first rectifier is connected to a generator of a DC wind turbine generator set, an output end of the first rectifier is connected to a generator-side end of a first inverter, and a grid-side end of the first inverter is used to be connected to a grid. a second converter, comprising a second rectifier, an input end of the second rectifier being connected to the generator, The second converter is connected in parallel with the first converter and does not include an inverter, and an output end of the second rectifier is electrically connected to a load.

2. The DC wind turbine generator set according to claim 1, characterized in that: The first inverter is a bidirectional inverter, and a support capacitor and a chopper circuit are connected between the machine-side end of the first inverter and the output end of the first rectifier, and the chopper circuit is connected in parallel with the support capacitor.

3. The DC wind turbine generator set according to claim 1, characterized in that: The first converter and the second converter are three-level converters, and the positive busbars, negative busbars, and neutral lines of the first converter and the second converter are connected in parallel accordingly.

4. The DC wind turbine generator set according to claim 1, characterized in that: The first inverter and the second rectifier output electric energy to the outside at the same time, and the ratio of the output power of the second rectifier to the output power of the first inverter is greater than 1.

5. The DC wind turbine generator set according to claim 4, characterized in that: A ratio of the output power of the second rectifier to the output power of the first inverter is greater than or equal to 5 and less than or equal to 50.

6. The DC wind turbine generator set according to claim 1, characterized in that: The load includes a DC load of the first converter and a DC load of the second converter, and the load also includes an external load of the DC wind turbine generator set, and the output end of the second rectifier is connected to the external load via a DC-DC converter and / or a DC-AC converter.

7. The DC wind turbine generator set according to claim 1, characterized in that: The DC wind turbine generator set further includes an energy storage system, which is connected to the output end of the first rectifier via a switch.

8. A control method for a DC wind turbine generator set, characterized in that: The DC wind turbine generator set is a DC wind turbine generator set according to any one of claims 1 to 7, and the control method comprises: Under power generation conditions, controlling the first inverter of the first converter to output a first power, and controlling the second rectifier to output a second power; Under power usage conditions, the first inverter is controlled to obtain electric energy from the power grid, and the obtained electric energy is supplied to the load via the machine-side input end of the first inverter and the output end of the second rectifier.

9. The control method of a DC wind turbine generator set according to claim 8, characterized in that: A ratio of the first power to the second power is less than 1 / 5.

10. The control method of a DC wind turbine generator set according to claim 8, characterized in that: The control method further includes controlling the energy storage system to supply power to the load via the DC bus of the first converter and / or the second converter when the power grid fails and the generator of the wind turbine generator set does not generate power.

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