A wind-diesel storage island DC network system based on wind turbine generator sets

Abstract

The present application discloses a wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set, which relates to the field of grid construction. The system includes: a diesel generator set, including a diesel-electric controller and multiple diesel generation branches, with some or all of the diesel generation branches serving as voltage sources for power supply; a wind turbine generator set including a wind power controller and multiple wind generation branches, with some or all of the wind generation branches serving as voltage sources for power supply, and / or some of the wind generation branches serving as current sources for grid power supply; an energy storage controller controls the grid-connected energy storage unit to obtain electrical energy from the DC bus for charging or as a voltage source, and the grid-connected energy storage unit to obtain electrical energy from the DC bus for charging or as a current source for grid power supply; and a DC networking device distributes the power supplied by the diesel generator set, wind turbine set, and / or energy storage device to the grid load. The technical solution of the present application improves the utilization rate of the wind turbine generator set and reduces the difficulty of network control.

Description

Technical Field

[0001] The present application relates to the technical field of wind turbine grid-connected control, and in particular to a wind-diesel-storage island DC networking system based on a grid-connected wind turbine. Background Art

[0002] Currently, for electricity consumption in remote areas such as island microgrids and non-fossil energy production areas, a microgrid model that integrates wind, storage, and diesel is often used. This type of microgrid usually uses diesel generators and wind turbines to build an AC grid to power the AC loads in the area. When AC power is connected to the grid, it is difficult to control it. The frequency and phase of each supply voltage need to be adjusted to be consistent, which makes grid control more difficult. Moreover, in the existing microgrid model, wind turbines are usually unable to form a power supply network independently and need to be supplied by the grid in the form of a current source. In other words, the existing solution has a strong dependence on diesel generators and low utilization of wind resources. Summary of the Invention

[0003] The technical problem to be solved by this application is that the existing technology has high difficulty in controlling the grid when constructing microgrids and has a strong reliance on diesel power generation, and thus provides a wind-diesel storage island DC networking system based on a grid-connected wind turbine generator set.

[0004] The technical solution of this application provides a wind-diesel storage island DC networking system based on a grid-connected wind turbine generator set, including:

[0005] The DC networking device is connected to the grid load and the following via the DC bus:

[0006] A diesel generator set includes a diesel-electric controller and a plurality of diesel-electric generating branches, each of which includes a diesel generator and a diesel-electric rectifier converter connected in series; the diesel-electric controller controls part or all of the diesel-electric generating branches to serve as a voltage source for power supply;

[0007] A wind turbine generator set includes a wind power controller and multiple wind power generation branches, each of which includes a wind turbine generator and a wind power rectifier converter connected in series, and a grid-connected converter and a grid-following converter are provided in the wind turbine generator; the wind power controller controls some or all of the wind power generation branches to serve as voltage sources for power supply, and / or controls some of the wind power generation branches to serve as current sources for grid-following power supply;

[0008] An energy storage device includes an energy storage controller, a grid-connecting energy storage unit, and a grid-following energy storage unit; the energy storage controller controls the grid-connecting energy storage unit to obtain electric energy from the DC bus for charging, or controls the grid-connecting energy storage unit to serve as a voltage source for power supply; the energy storage controller controls the grid-following energy storage unit to obtain electric energy from the DC bus for charging, or controls the grid-following energy storage unit to serve as a current source for grid-following power supply;

[0009] The diesel-electric controller, the wind-power controller and the energy storage controller are communicatively connected, and the DC networking device distributes the power generated by the diesel generator set, the wind generator set and / or the energy storage device to the grid load.

[0010] Preferably, in some schemes, the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set, the wind turbine generator set also includes a first backup power supply, which provides power to the wind power controller and provides starting power to the wind turbine under the control of the wind power controller.

[0011] Preferably, in the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set described in some schemes, the first backup power supply is a backup diesel generator or a first inverter AC, wherein: the first inverter AC converts the electric energy on the DC bus to obtain electric energy compatible with the wind power controller or the wind turbine generator.

[0012] Preferably, in some schemes of the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set, in the wind turbine generator set, the wind turbine in which the grid-connected converter is connected to the working state is defined as a wind turbine as a voltage source, and the wind turbine in which the grid-connected converter is connected to the working state is defined as a wind turbine as a current source: the wind turbine as a voltage source provides electrical energy to the wind turbine as a current source under the control of the wind power controller.

[0013] Preferably, in some solutions of the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set, the energy storage device also includes a second backup power supply, which provides power to the energy storage controller.

[0014] Preferably, in some schemes of the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set, the second backup power supply is a backup diesel generator or a second inverter AC, wherein: the second inverter AC converts the electric energy on the DC bus to obtain electric energy compatible with the energy storage controller.

[0015] Preferably, in some schemes, the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set, the grid-connected energy storage unit includes a grid-connected energy storage battery, a grid-connected energy storage controller and a grid-connected rectifier converter, and the grid-connected energy storage battery is electrically connected to the DC bus via the grid-connected rectifier converter; the second backup power supply provides power to the grid-connected energy storage controller.

[0016] Preferably, in some schemes, the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set, the grid-connected energy storage unit includes a grid-connected energy storage battery, a grid-connected energy storage controller and a grid-connected rectifier converter, and the grid-connected energy storage battery is electrically connected to the DC bus via the grid-connected rectifier converter; the second backup power supply provides electrical energy for the grid-connected energy storage controller.

[0017] Preferably, in some solutions, the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set includes the following forms of grid construction: wind turbine generator set grid construction, grid-connected energy storage unit grid construction, and multi-source grid construction, wherein:

[0018] The wind turbine generator network structure includes:

[0019] Some or all of the wind turbines in the wind turbine generator set are independently powered, wherein some of the wind turbines are used as voltage sources for power supply; some of the wind turbines in the wind turbine generator set and / or the grid-following energy storage units are used as current sources for grid-following power supply;

[0020] The networking forms of the networked energy storage units include:

[0021] The grid-connected energy storage unit is used as a reference voltage source to supply power, and the grid-following energy storage unit is used as a current source to supply power to the grid; or

[0022] The grid-connected energy storage unit is used as a reference voltage to supply power, and the grid-following energy storage unit and some or all of the wind turbines in the wind turbine generator set are used to supply power to the grid;

[0023] The multi-source networking forms include:

[0024] Part or all of the diesel generators in the diesel generator set, part or all of the wind generators in the wind generator set, and at least two components in the grid energy storage unit output the same reference voltage as voltage sources for synchronous power supply;

[0025] The grid-connected energy storage unit and / or some wind turbines in the wind turbine generator set are grid-connected for power supply.

[0026] Preferably, in some schemes of the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set, when the wind turbine generator set is supplying power, if the electric energy output by the DC networking device exceeds the power demand of the grid load, part of the electric energy provided by the wind turbine is used to charge the grid-connected energy storage unit and / or the grid-connected energy storage unit.

[0027] Compared with the existing technology, the above technical solution provided by this application has the following technical effects:

[0028] The wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set provided by the present application includes a DC networking device, a diesel generator set, a wind turbine generator set and an energy storage device. Both the diesel generator set and the wind turbine generator set are provided with a rectifier converter, which can convert the AC power generated by the diesel generator and the wind turbine generator into DC power and then transmit it to the DC bus; the output of the energy storage system is originally DC power. Therefore, the DC networking device is connected to DC power through the DC bus. When the power provided by each component is networked, only the DC power is put in or cut out, which simplifies the grid control and reduces the difficulty of networking. The wind turbine of the wind turbine generator set is equipped with a grid converter and a grid converter. Depending on whether the grid converter and the grid converter are in working state, different wind turbines can participate in the power supply as a voltage source or a current source, thereby forming a grid-connected wind turbine generator set. The energy storage device includes a grid-building energy storage unit and a grid-following energy storage unit. The grid-building energy storage unit can be used as a voltage source to supply power, and the grid-following energy storage unit can be used as a current source to supply power to the grid. Therefore, even if the diesel generator set is disconnected from the grid, the networking system in this application can use the wind turbine as a voltage source in the grid-following wind generator set and one or two of the grid-building energy storage units as a voltage source in the energy storage system as voltage sources to realize network formation, thereby reducing dependence on the diesel generator set and improving the utilization rate of the wind generator set. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural block diagram of a wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to an embodiment of the present application;

[0030] Figure 2 This is a block diagram of the internal structure of a wind turbine generator set according to one embodiment of the present application;

[0031] Figure 3 This is a block diagram of the internal structure of the energy storage device according to one embodiment of the present application;

[0032] Figure 4 This is a structural block diagram of a wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set as described in another embodiment of the present application. DETAILED DESCRIPTION

[0033] The specific implementation of this application is further described below with reference to the accompanying drawings.

[0034] It is easy to understand that according to the technical solution of this application, a variety of structural methods and implementation methods can be replaced with each other by those skilled in the art without changing the essential spirit of this application. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of this application and should not be regarded as the entire application or as a limitation or restriction of the technical solution of the application.

[0035] This embodiment provides a wind-diesel storage island DC network system based on a wind turbine generator set. Figure 1 Shown, including:

[0036] The DC networking device connects the grid load, diesel generator set, wind turbine generator set and energy storage device through the DC bus. The diesel generator set, wind turbine generator set and energy storage device are connected in parallel. As shown in the figure:

[0037] A diesel generator set includes a diesel-electric controller and multiple diesel generator branches. Each of these branches includes a diesel generator and a diesel-electric rectifier-converter connected in series. The diesel-electric controller controls some or all of the diesel generator branches to act as voltage sources. The diesel-electric rectifier-converter is a rectifier-converter that performs both rectification and conversion functions, converting the AC power output from the diesel generator into DC power. Different diesel generator branches can be in either an active or inactive state. An active diesel generator branch outputs DC power to the DC bus, while an inactive diesel generator is effectively disconnected from the grid, reducing diesel usage.

[0038] A wind turbine generator set includes a wind turbine controller and multiple wind power generation branches. Each wind power generation branch includes a wind turbine generator and a wind power rectifier converter connected in series. A grid-connected converter and a grid-following converter are provided within the wind turbine generator. The wind turbine controller controls some or all of the wind power generation branches to function as voltage sources and / or some of the wind power generation branches to function as current sources for grid-following power. As previously mentioned, a wind power rectifier converter is similar to a diesel-electric rectifier converter and functions to convert the AC power generated by the wind turbine into DC power. Furthermore, the wind turbine includes multiple converters, and the converters that enter the operating state within different wind turbines can be the same or different. If the grid-connected converter within the wind turbine generator is operating, the wind turbine can directly participate in the grid construction as a voltage source, outputting DC voltage to the DC bus. If the grid-following converter within the wind turbine generator is operating, the wind turbine can function as a current source for grid-following power generation. In specific implementation, a full-power converter can be set in the wind turbine. Taking a 10MW full-power converter as an example, it includes two groups of 5MW converters controlled in parallel, one of which is a 5MW converter using grid control and the other is a 5MW converter using grid control. Each group of converters includes a rectifier-side converter and an inverter-side converter. The converter using grid control is used as a controlled voltage source to directly generate voltage amplitude and frequency according to demand. At this time, there is no need to consider phase synchronization, which is equivalent to a reference voltage source. The converter using grid control is used as a controlled current source, which is synchronized with the grid voltage phase through phase-locked loop technology and controls the output power by controlling the current amplitude. In this application, the working status of different wind turbines is controlled according to networking requirements through a wind turbine controller.

[0039] The energy storage device includes an energy storage controller, a grid-connected energy storage unit, and a grid-connected energy storage unit; the energy storage controller controls the grid-connected energy storage unit to obtain electric energy from the DC bus for charging, or controls the grid-connected energy storage unit to supply power as a voltage source; the energy storage controller controls the grid-connected energy storage unit to obtain electric energy from the DC bus for charging, or controls the grid-connected energy storage unit to supply power to the grid as a current source. As mentioned above, the grid-connected energy storage unit can be regarded as a voltage source, and the grid-connected energy storage unit can be regarded as a current source. When it needs to be charged, electric energy is obtained from the DC bus and converted into a voltage value suitable for charging the energy storage unit to achieve charging. When it needs to be supplied with power, the grid-connected energy storage unit can directly supply power as a voltage source, and the grid-connected energy storage unit can supply power to the grid as a current source.

[0040] The diesel-electric controller, the wind power controller, and the energy storage controller are communicatively connected, and the DC networking device distributes the power generated by the diesel generator set, the wind power generator set, and / or the energy storage device to the grid load. The DC networking completes the DC networking after obtaining the DC power provided by each power supply component from the bus, and then provides the power to the grid load. If the grid load requires DC power, it can directly use the power provided by the DC networking device. If the grid load requires AC power, it can convert the DC power output by the DC bus into AC power by setting an inverter in front of the power load for use by the load.

[0041] In the above-mentioned solution of this embodiment, the system includes a DC networking device, a diesel generator set, a wind turbine generator set, and an energy storage device. Both the diesel generator set and the wind turbine generator set are equipped with rectifier converters that can convert the AC power generated by the diesel generator and wind turbine into DC power and then transmit it to the DC bus. The energy storage system originally outputs DC power. As a result, the DC networking device receives only DC power through the DC bus. When networking the power provided by each component, only the DC power is switched on or off, simplifying grid control and reducing networking difficulty. The wind turbines in the wind turbine generator set are equipped with a grid-connecting converter and a grid-following converter. Depending on whether the grid-connecting converter and the grid-following converter are in operation, different wind turbines can participate in power supply as voltage sources or current sources, thereby forming a grid-connecting wind turbine generator set. The energy storage device includes a grid-connecting energy storage unit and a grid-following energy storage unit. The grid-connecting energy storage unit can serve as a voltage source for power supply, while the grid-following energy storage unit can serve as a current source for grid-following power supply. Therefore, even if the diesel generator set is disconnected from the grid, the networking system in this application can still use the wind turbine in the grid-connected wind generator set as the voltage source and one or two of the grid-connected energy storage units in the energy storage system as the voltage source to power the network, thereby reducing the dependence on the diesel generator set and improving the utilization rate of the wind generator set. The above technical solution of this application fills the gap in the technology of wind-diesel-storage integrated DC grid and multi-voltage source DC island grid.

[0042] Preferably, if Figure 2 As shown, the wind turbine generator set also includes a first backup power supply, which provides power to the wind power controller and provides starting power to the wind turbine generator under the control of the wind power controller. The backup power supply can be realized by pre-set components with power generation functions, such as large-capacity batteries, small power generation units, etc. By setting up a backup power supply, the wind turbine generator set can be self-started and the independent power supply of the wind turbine generator set can be completed. Further preferably, the first backup power supply is a backup diesel generator or a first inverter AC, wherein: Figure 4 As shown in , the first inverter AC converts the electric energy on the DC bus to obtain electric energy that is compatible with the wind power controller or the wind turbine. According to the power supply mode of the wind turbine generator set, if self-starting is required, the wind power controller can be powered by the first backup power supply, so that the wind power controller can control each wind turbine, such as controlling the start and stop of the wind turbine, unit protection, and control of the grid-forming converter and the grid-following converter in each wind turbine. If there is no wind or the wind is very small and it is difficult to drive the wind turbine blades, the first backup power supply can also be used to drive the wind turbine blades to start. In this process, the first backup power supply can be controlled by the wind turbine controller to change its energy supply size to match the electric energy required by the energy supply target.

[0043] Preferably, in the wind-diesel storage island DC networking system based on the grid-connected wind turbine generator set in the scheme, in the wind turbine generator set, the wind turbine connected to the grid converter in the working state is defined as a wind turbine as a voltage source, and the wind turbine connected to the grid converter in the working state is defined as a wind turbine as a current source: the wind turbine as a voltage source provides electrical energy to the wind turbine as a current source under the control of the wind power controller. When the wind turbine as a voltage source outputs a stable reference voltage during normal operation, it can provide excitation power for the wind turbine as a current source. Furthermore, the wind turbine as a voltage source can also provide power for the wind power controller and other components or parts that require electrical energy. Through this scheme, the utilization rate of wind power generation is further improved, and the consumption of resources such as diesel is reduced.

[0044] like Figure 3 As shown, in the wind-diesel-storage island DC networking system based on the grid-connected wind turbine generator set, the energy storage device also includes a second backup power supply, and the second backup power supply provides electrical energy to the energy storage controller. In this way, under the power supply of the second backup power supply, the energy storage controller can control the grid-connected energy storage unit to supply power as a voltage source, and control the grid-connected energy storage unit to supply power to the grid as a current source. When the networking is completed, the grid-connected energy storage unit can replace the second backup power supply to supply power to the energy storage controller and other equipment or components. Further preferably, the second backup power supply is a backup diesel generator or a second inverter AC, wherein: Figure 4 As shown, the second inverter converts the electrical energy on the DC bus to generate electrical energy compatible with the energy storage controller. Typically, the first and second backup power supplies are preferably implemented using an inverter to convert voltage. To prevent insufficient DC bus power from affecting system networking, a backup diesel generator can be used as an auxiliary device.

[0045] Preferably, if Figure 3 As shown in , the grid energy storage unit includes a grid energy storage battery, a grid energy storage controller and a grid rectifier converter. The grid energy storage battery is electrically connected to the DC bus via the grid rectifier converter; the second backup power supply provides electrical energy to the grid energy storage controller. The grid rectifier converter can realize a bidirectional voltage conversion function. When the grid energy storage battery needs to be charged, the grid rectifier converter converts the electrical energy on the DC bus into a voltage value that is compatible with the charging requirements of the grid energy storage battery. When the grid energy storage battery is needed as a voltage source, the grid rectifier converter can boost the voltage value output by the grid energy storage battery and supply it to the DC bus. Similarly, as shown in Figure 3As shown, the grid-connected energy storage unit includes a grid-connected energy storage battery, a grid-connected energy storage controller, and a grid-connected rectifier converter. The grid-connected energy storage battery is electrically connected to the DC bus via the grid-connected rectifier converter. The second backup power supply provides power to the grid-connected energy storage controller. The grid-connected rectifier converter can also convert power on the DC bus to a voltage suitable for charging the grid-connected energy storage battery, and convert power output from the grid-connected energy storage battery into power suitable for grid power supply before transmitting it to the DC bus.

[0046] The system structure using the above wind turbine generator set and energy storage device is as follows Figure 4 The system can construct a power grid in the following ways: diesel generator group grid, wind turbine group grid, grid energy storage unit grid and multi-source grid, where:

[0047] The diesel generator controller in the diesel generator set monitors the operating status of each diesel generator, determining whether the generator set is functioning properly to maintain network requirements. It also communicates data with the wind turbine controller in the wind turbine generator set and the energy storage controller in the energy storage device, enabling the three controllers to share information and coordinate control. The wind turbine generator set is equipped with a device to monitor wind conditions. This information is transmitted to the wind turbine controller, which then determines whether the wind conditions are sufficient for starting the wind turbine and how many wind turbines can be started, thereby determining whether the wind turbine can contribute to the grid. The energy storage controller in the energy storage device monitors the storage capacity of the grid-connecting and grid-following energy storage units, determining whether either unit requires charging or can contribute to power supply. Because these three controllers can transmit information to each other, they can share status data of the diesel generator set, wind turbine generator set, and energy storage device, enabling coordinated control. For example: when an abnormality occurs in a diesel generator set, the wind turbine generator set determines whether it can build a power grid based on the wind conditions, and the energy storage device determines whether it can build a power grid based on the storage capacity of the energy storage unit. If either of the two can build a power grid, the power grid construction can still be completed. For another example, even if the diesel generator set can currently build a power grid, the wind turbine generator set can provide sufficient electricity under the current wind conditions. At this time, the diesel generator set can bear a small amount of load or even no load. The wind turbine generator set builds the network completely and bears as much load as possible, thereby improving the efficiency of wind energy utilization. A plurality of switches can be configured in the DC networking device. The switch connected to the output of the diesel generator set is controlled by the diesel-electric controller, the switch connected to the output of the wind turbine generator set is controlled by the wind power controller, and the switch connected to the output of the energy storage device is controlled by the energy storage controller. The conduction or disconnection of each switch is controlled according to the equipment components connected to the power grid to realize the connection of different power sources to the grid. Specifically, the networking conditions of different networking forms are as follows:

[0048] 1. The wind turbine generator network structure:

[0049] By monitoring the wind conditions, when the wind conditions meet the working conditions of the wind turbines, the wind turbines are used first to build the power grid to improve the efficiency of wind energy utilization. The first backup power supply can be used to power the wind power controller, and the wind turbine generator set starts to generate electricity and is connected to the grid. At this time, the first backup power supply is used to start the wind turbine generator set and power the wind power controller; the AC power output by the wind turbine generator set is converted into DC power by the wind power rectifier converter. The wind turbine generator set is used as a voltage source to build the power grid system. The wind turbine generator set can charge the grid-following energy storage unit and the grid-building energy storage unit. Specifically, the working status of each component includes:

[0050] 1.1 Independent power supply of wind turbines

[0051] By monitoring wind conditions, when wind conditions consistently meet the operating requirements of wind turbines, the wind turbine generator set independently connects to the grid for power supply. Some wind turbines use the grid-connecting converter as voltage sources to output a stable reference voltage for the DC grid. Some wind turbines connect to the grid via the grid-connecting converter as grid-connecting current sources. In this case, the wind turbines acting as voltage sources can provide excitation power for the wind turbines acting as current sources. The wind turbines acting as voltage sources can also power the wind turbine controller and other electrical components, such as the converters. Furthermore, if the wind turbine generator set has power redundancy, it can also charge the grid-connecting energy storage unit and the grid-connecting energy storage unit. That is, when the wind turbine generator set is supplying power, if the power output of the DC networking device exceeds the power demand of the grid load, a portion of the power provided by the wind turbine generator is used to charge the grid-connecting energy storage unit and / or the grid-connecting energy storage unit. This achieves maximum utilization efficiency of the wind turbine generator set.

[0052] 1.2 Wind-diesel energy storage integrated power supply using wind turbines as grid reference voltage source

[0053] As before, wind turbines serve as voltage sources to build the grid and as the main power supply for the DC grid;

[0054] The grid-following energy storage unit acts as a current source to supply power to the grid, ensuring the power supply stability of the DC grid.

[0055] 2. Networking form of the networked energy storage unit:

[0056] By monitoring the operating status and wind conditions of the diesel generator sets, it is determined whether the diesel generator sets have abnormal fuel level alarms or equipment damage, and whether the wind conditions support the normal operation of the wind turbine generator sets and their participation in grid construction. If neither the operating status nor the wind conditions of the diesel generator sets can support grid construction, the second backup power source (the backup diesel generator) will power the energy storage device's energy storage controller. The energy storage controller will activate the grid-forming energy storage unit, which will act as a voltage source to provide a stable reference voltage for the DC grid. The grid-following energy storage unit will act as a current source to provide power output to the DC grid. At this time, the grid-forming energy storage unit will serve as the sole reference voltage source. When the DC grid is fully constructed, the grid-forming energy storage unit will power the energy storage controller and various devices such as converters.

[0057] If the wind conditions improve and some or all of the wind turbines can be started, some or all of the wind turbines can be used as current sources to supply power to the grid.

[0058] 3. The multi-source network construction form:

[0059] If the diesel generator set is in stable working condition and the wind conditions support the normal operation of the wind generator set, multi-source networking can be realized, that is, some or all of the diesel generators in the diesel generator set, some or all of the wind generators in the wind generator set and at least two components in the network energy storage unit act as voltage sources to output the same reference voltage for synchronous power supply; at this time, each voltage source uniformly outputs the same reference voltage.

[0060] The grid-connected energy storage unit and / or some of the wind turbines in the wind turbine generator set provide grid-connected power. That is, the grid-connected energy storage unit always serves as a current source for grid-connected power supply, and some of the wind turbines can also be separated to serve as current sources for grid-connected power generation. The multi-source grid structure effectively increases the stability of the DC grid by jointly forming a DC grid with multiple voltage sources. At this point, the first backup power supply and the second backup power supply can be achieved by converting the voltage on the DC bus using a first inverter AC and a second inverter AC, respectively.

[0061] The various networking forms in the above schemes of this application all use DC networking technology. Compared with AC power grids, there is no need to consider issues such as frequency and phase, and power grid connection and load switching are more convenient. It is possible to realize independent networking of wind, storage, and diesel, as well as collaborative networking, and to increase the stability of the DC power grid by adding voltage sources of different types and sources. The wind turbine generator set uses a grid-building converter and a grid-following converter to divide the wind turbine into two power supply modes: voltage source and current source, thereby realizing independent DC networking of the wind turbine generator set. At the same time, it is equipped with two sets of energy storage units. The grid-building energy storage unit can be used as a voltage source to independently build a network, and the grid-following energy storage unit can be used as a current source to supply power to the grid, realizing energy storage networking and energy storage grid-following in the same system.

[0062] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0063] The above are only the principles and preferred embodiments of the present application. It should be noted that, for those skilled in the art, on the basis of the principles of the present application, several other modifications can be made, which should also be considered as the scope of protection of the present application.

Claims

1. A wind-diesel storage island DC networking system based on a grid-connected wind turbine generator set, characterized in that: include: The DC networking device is connected to the grid load and the following via the DC bus: A diesel generator set includes a diesel-electric controller and a plurality of diesel-electric generating branches, each of which includes a diesel generator and a diesel-electric rectifier converter connected in series; the diesel-electric controller controls part or all of the diesel-electric generating branches to serve as a voltage source for power supply; A wind turbine generator set includes a wind power controller and multiple wind power generation branches, each of which includes a wind turbine generator and a wind power rectifier converter connected in series, and a grid-connected converter and a grid-following converter are provided in the wind turbine generator; the wind power controller controls some or all of the wind power generation branches to serve as voltage sources for power supply, and / or controls some of the wind power generation branches to serve as current sources for grid-following power supply; The wind power controller determines whether the wind turbine generator set can construct a power grid according to wind conditions; An energy storage device includes an energy storage controller, a grid-building energy storage unit, and a grid-following energy storage unit; the energy storage controller controls the grid-building energy storage unit to obtain electric energy from the DC bus for charging, or controls the grid-building energy storage unit to supply power as a voltage source; the energy storage controller controls the grid-following energy storage unit to obtain electric energy from the DC bus for charging, or controls the grid-following energy storage unit to supply power to the grid as a current source; the grid-following energy storage unit includes a grid-following energy storage battery, a grid-following energy storage controller, and a grid-following rectifier converter, the grid-following energy storage battery being electrically connected to the DC bus via the grid-following rectifier converter; the energy storage controller determines whether the grid-following energy storage unit can construct a power grid based on the storage capacity of the grid-following energy storage unit; The diesel-electric controller, the wind power controller and the energy storage controller are communicatively connected, and the DC networking device distributes the power generated by the diesel generator set, the wind generator set and / or the energy storage device to the grid load; wherein: When the diesel generator set does not participate in grid construction, if any one of the wind generator set and the grid construction energy storage unit is capable of constructing a grid, the wind generator set and / or the grid construction energy storage unit is used to construct the grid.

2. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to claim 1 is characterized in that: The wind turbine generator set further includes a first backup power supply, which provides electrical energy to the wind power controller and provides starting electrical energy to the wind turbine generator under the control of the wind power controller.

3. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to claim 2 is characterized in that: The first backup power supply is a backup diesel generator or a first inverter AC, wherein: the first inverter AC converts the electric energy on the DC bus to obtain electric energy compatible with the wind power controller or the wind turbine.

4. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to claim 1 is characterized in that: In the wind turbine generator set, the wind turbine generator with the grid-connected converter connected to the working state is defined as a wind turbine generator serving as a voltage source, and the wind turbine generator with the grid-following converter connected to the working state is defined as a wind turbine generator serving as a current source: the wind turbine generator serving as a voltage source provides electrical energy to the wind turbine generator serving as a current source under the control of the wind power controller.

5. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to claim 1 is characterized in that: The energy storage device also includes a second backup power supply, which provides electrical energy to the energy storage controller.

6. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to claim 5 is characterized by: The second backup power supply is a backup diesel generator or a second inverter AC, wherein the second inverter AC converts the electric energy on the DC bus to obtain electric energy that is compatible with the energy storage controller.

7. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to claim 6 is characterized in that: The second backup power supply provides electrical energy to the grid-connected energy storage controller.

8. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to claim 7 is characterized in that: The grid-connected energy storage unit includes a grid-connected energy storage battery, a grid-connected energy storage controller, and a grid-connected rectifier converter, wherein the grid-connected energy storage battery is electrically connected to the DC bus via the grid-connected rectifier converter; The second backup power supply provides electrical energy to the grid-connected energy storage controller.

9. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to any one of claims 1 to 8, characterized in that: The forms of grid construction of the system include: wind turbine group grid construction, grid energy storage unit grid construction and multi-source grid construction, wherein: The wind turbine generator network structure includes: Some or all of the wind turbines in the wind turbine generator set are independently powered, wherein some of the wind turbines are used as voltage sources for power supply; some of the wind turbines in the wind turbine generator set and / or the grid-following energy storage units are used as current sources for grid-following power supply; The networking forms of the networked energy storage units include: The grid-connected energy storage unit is used as a reference voltage source to supply power, and the grid-following energy storage unit is used as a current source to supply power to the grid; or The grid-connected energy storage unit is used as a reference voltage to supply power, and the grid-following energy storage unit and some or all of the wind turbines in the wind turbine generator set are used to supply power to the grid; The multi-source networking forms include: Part or all of the diesel generators in the diesel generator set, part or all of the wind generators in the wind generator set, and at least two components in the grid energy storage unit output the same reference voltage as voltage sources for synchronous power supply; The grid-connected energy storage unit and / or some wind turbines in the wind turbine generator set are grid-connected for power supply.

10. The wind-diesel-storage island DC networking system based on a grid-connected wind turbine generator set according to claim 9 is characterized in that: When the wind turbine generator set is supplying power, if the electric energy output by the DC networking device exceeds the power demand of the grid load, part of the electric energy provided by the wind turbine generator is used to charge the networking energy storage unit and / or the grid-connected energy storage unit.

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