Novel energy storage integrated converter for wind power generation in micro-grid environment

Abstract

The invention provides a novel energy storage integrated converter for wind power generation in a micro-grid environment, relates to the technical field of wind power generation equipment, and solves the problems of converter damage, energy waste and complex maintenance caused by voltage fluctuation in the micro-grid environment. The converter comprises: an electrical system for performing boost grid connection after performing AC-DC-AC conversion on electric energy generated by a generator; the water cooling system is used for providing water cooling heat dissipation in the operation process; the fire fighting system is used for monitoring the fire behavior at the position of each system and implementing automatic fire extinguishing operation; the energy storage system is connected to a power module of the electrical system, and the main control system is connected between the energy storage system and the power module; the energy storage system is used for storing the discharged electric energy and providing the stored electric energy for the main control system in case of sudden abnormal conditions; the energy storage control system controls the power module to be connected and disconnected with an electric energy loop between the energy storage system and the main control system; energy waste is avoided, and the utilization rate of electric energy is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation equipment, and in particular to a novel energy storage integrated converter for wind power generation in a microgrid environment. Background Art

[0002] For onshore wind power, regions with superior natural conditions such as abundant wind energy resources have successfully deployed a large number of wind power facilities, contributing stable and clean electricity to the power grid.

[0003] However, when facing potential wind energy resource areas located in complex terrain conditions such as mountainous areas, due to geographical environment and inconvenient transportation, wind power projects in these areas are often difficult to directly connect to the existing large-scale power grid system for power transmission, but are more likely to operate in the form of microgrids. In such a microgrid environment, the voltage level is prone to large fluctuations, especially during high voltage or low voltage ride-through. This unstable state is very likely to cause damage to the converter, affecting the normal operation and safety of the entire system.

[0004] In addition, offshore wind farms face even more severe challenges. The marine environment is not only subject to changeable climate and severe salt spray corrosion, but also requires diesel generators to restart the system after a power outage (the so-called "black start"). This undoubtedly increases operating costs and brings additional environmental pollution problems. Therefore, in view of the above situation, it is particularly important to improve the design of existing converters to adapt to more severe working conditions.

[0005] Traditional converter designs often include components such as Chopper resistors, soft-start circuits, and uninterruptible power supplies (UPS) to ensure that the equipment can maintain stable and reliable operation under various working conditions. However, such a complex structure also means that when a fault occurs, the maintenance process will become extremely difficult; in addition, when dealing with high / low voltage ride-through events, although the excess power consumed by the Chopper resistor can protect the system from damage, it also causes a considerable degree of energy waste, especially in small-scale applications that rely on microgrid power supply. This phenomenon is particularly prominent. In summary, the development of a new generation of converter technology that can effectively cope with extreme working environments and improve energy utilization efficiency has become a key issue that needs to be solved urgently. Summary of the invention

[0006] Based on the current status of the background technology, the purpose of the present invention is to solve the problems of converter damage, energy waste and complex maintenance caused by voltage fluctuations in a microgrid environment, and at the same time enhance the reliability and black start capability of the system under extreme conditions. Therefore, a new type of wind power generation energy storage integrated converter in a microgrid environment is proposed. The converter equipped with an energy storage system can not only simplify the converter structure design, improve maintenance efficiency and reliability, but also store the discharged electric energy for power supply to the converter and the main body of the wind turbine, thereby avoiding energy waste and effectively improving the utilization rate of electric energy.

[0007] The present invention adopts the following technical solutions to achieve the purpose:

[0008] A novel energy storage integrated converter for wind power generation in a microgrid environment, the converter comprising an electrical system, a water cooling system, a fire protection system, an energy storage system and an energy storage control system, wherein:

[0009] One end of the electrical system is connected to the generator of the wind turbine, and the other end is connected to the external power grid. The electrical system is used to convert the electric energy generated by the generator into AC-DC-AC through the power module and then send it to the grid-side transformer for boosting and grid connection.

[0010] The water cooling system is used to provide water cooling and heat dissipation for the electrical system and energy storage system during operation;

[0011] The fire protection system is used to monitor the fire conditions at each system location of the converter and automatically extinguish the fire when a fire occurs;

[0012] The energy storage system is connected to the power module in the electrical system. At the same time, the main control system of the wind turbine is connected to the connection circuit between the energy storage system and the power module. The energy storage system is used to store the electric energy discharged by the power module and provide the stored electric energy to the main control system in case of sudden abnormal conditions.

[0013] The energy storage control system is connected to the energy storage system. The energy storage control system is used to monitor the electric energy storage situation of the energy storage system, and at the same time control the on and off of the electric energy circuit between the power module and the energy storage system and the main control system respectively.

[0014] The converter of the present invention does not have a traditional soft start circuit, UPS and Chopper resistor, but replaces them with an energy storage system. All components in the energy storage system circuit are modularly configured to facilitate maintenance and replacement. In addition, the energy storage system is suspended on the outer wall of the converter cabinet in the form of a backpack, occupying a part of the overall space.

[0015] Specifically, both ends of the power module of the electrical system are respectively connected to the generator and the external power grid through circuit breakers; starting from the motor side, the power module includes a rectifier and an inverter connected in sequence, with a DC busbar between the two; reactors are provided on the side of the rectifier and the inverter away from the DC busbar, and filter modules are connected between both ends of the power module and the corresponding circuit breakers; a fuse is also connected in series in the circuit where the power module is located.

[0016] Specifically, the energy storage system is connected to the DC busbar of the power module in the electrical system through a bidirectional chopper, and switches and fuses are also provided on the connection line between the bidirectional chopper and the DC busbar.

[0017] Specifically, the main control system of the wind turbine is connected to the connection line between the bidirectional chopper and the energy storage system through an auxiliary transformer, a reactor and an inverter connected in sequence; a filter module is also connected between the auxiliary transformer and the reactor; switches and fuses are also provided on the connection loop between the main control system and the energy storage system.

[0018] Preferably, the batteries in the energy storage system adopt all-solid-state energy storage batteries, and the corresponding battery clusters adopt a full-series mode; the capacity of the energy storage system is 20% of the capacity of the wind turbine set, the energy storage system has a factory charge state of a preset percentage value, and is also configured with a battery management system. The safety signal in the battery management system has two groups of signal lead-out points, one group is connected to the main control system, and the other group is connected to the wind turbine switch cabinet; the battery management system is used to collect the temperature, voltage, and current data of the energy storage system and send them to the main control system, and the main control system is used to set the control logic of the energy storage control system according to the received data.

[0019] Furthermore, the energy storage control system operates according to the battery status of the energy storage system under the control logic; the energy storage control system is used to connect the power module in the electrical system and the electric energy circuit of the energy storage system when the energy storage system is in a power-deficient state, so as to realize the storage of discharged energy in the energy storage system; the energy storage control system is also used to disconnect the power module in the electrical system and the electric energy circuit of the energy storage system when the energy storage system is in a fully charged state, and simultaneously connect the power module in the electrical system and the electric energy circuit of the main control system, so as to realize the direct conversion of discharged energy to supply the main control system and its supporting equipment for use;

[0020] In the event of an unexpected abnormal situation, the energy storage control system is also used to simultaneously connect the energy storage system to the power circuits of the power modules in the main control system and electrical system to achieve power supply in the event of an unexpected abnormal situation.

[0021] In summary, due to the adoption of this technical solution, the beneficial effects of the present invention are as follows:

[0022] First, by integrating the energy storage system, the present invention can utilize the electric energy pre-stored in the energy storage system to realize the first black start of the offshore wind turbine in an offshore environment, greatly improving the system's independent operation capability and ability to cope with emergencies.

[0023] Secondly, when facing high voltage or low voltage ride-through of wind turbines, traditional technologies usually rely on Chopper resistors to consume excess power to protect the converter. However, the present invention uses a bidirectional chopper to adjust the voltage and effectively stores this part of energy that would otherwise be wasted into the energy storage system, achieving effective energy recovery and reuse, thereby greatly reducing power loss and improving the efficiency of the entire wind power system.

[0024] In addition, the present invention also designs a mechanism that can provide necessary power support for important equipment inside the wind turbine, such as the main control system, lighting facilities, etc., in the event of an emergency shutdown. Specifically, the electric energy stored in the energy storage system can be converted into AC power by an inverter, and then supplied to the auxiliary transformer after filtering, ensuring that key functional components can continue to operate normally even when the power grid is out of power. At the same time, when the external power grid fails, the energy storage system can also reverse power the converter to maintain the stable operation of the entire system.

[0025] Finally, in response to the soft start requirements of wind turbines, the present invention can quickly increase the voltage level on the DC busbar during the startup phase through its built-in energy storage system in conjunction with the bidirectional chopper, thereby accelerating the soft start process and further enhancing the response speed and flexibility of the system. In short, the converter of the present invention not only improves the overall performance and reliability of the wind power generation system, but also promotes technological innovation and development in the field of clean energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the system composition of the energy storage integrated converter of the present invention;

[0027] Figure 2 It is a schematic diagram of the electrical principle of the energy storage integrated converter of the present invention;

[0028] Figure 3 It is a schematic diagram of the external structure layout of the energy storage integrated converter of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] A new type of wind power generation integrated energy storage converter in a microgrid environment, see Figure 1 The converter includes electrical system, water cooling system, fire protection system, energy storage system and energy storage control system. The systems are summarized as follows:

[0033] One end of the electrical system is connected to the generator of the wind turbine, and the other end is connected to the external power grid. The electrical system is used to convert the electric energy generated by the generator into AC-DC-AC through the power module and then send it to the grid-side transformer for boosting and grid connection.

[0034] The water cooling system is used to provide water cooling and heat dissipation for the electrical system and energy storage system during operation;

[0035] The fire protection system is used to monitor the fire conditions at each system location of the converter and automatically extinguish the fire when a fire occurs;

[0036] The energy storage system is connected to the power module in the electrical system, and at the same time, the main control system of the wind turbine is connected to the connection circuit between the energy storage system and the power module; the energy storage system is used to store the electric energy discharged by the power module, and provide the stored electric energy to the main control system in case of sudden abnormal conditions;

[0037] The energy storage control system is connected to the energy storage system. The energy storage control system is used to monitor the electric energy storage situation of the energy storage system, and at the same time control the on and off of the electric energy circuit between the power module and the energy storage system and the main control system respectively.

[0038] The converter of this embodiment does not have a traditional soft start circuit, UPS and Chopper resistor. The connection relationship between the electrical system of the converter and the electrical components of the energy storage system can be found in Figure 2 First, both ends of the power module of the electrical system are connected to the generator and the external grid through circuit breakers; from the motor side, the power module includes a rectifier and an inverter connected in sequence, with a DC busbar between the two. And the power module can be as follows Figure 2 The shown embodiment adopts a combination of multiple parallel connections.

[0039] As for the specific structure, reactors are provided on the side of the rectifier and the inverter away from the DC busbar, and filter modules are connected between the two ends of the power module and the corresponding circuit breaker to achieve a coordinated filtering effect; and a fuse is also connected in series in the circuit where the power module is located.

[0040] The group is preferred in this embodiment. The circuit breaker on the grid side of the power module is connected to the external grid through the corresponding transformer. A series fuse and a lightning protection module are also connected to the connection line between the circuit breaker and the transformer, and the other end of the lightning protection module is grounded.

[0041] The energy storage system is connected after being led out from the above-mentioned DC busbar. Specifically: the energy storage system is connected to the DC busbar of the power module in the electrical system through a bidirectional chopper (specifically, a bidirectional DC / DC chopper, which can realize bidirectional conversion of DC power), and switches and fuses are also provided on the connection line between the bidirectional chopper and the DC busbar.

[0042] As a preferred embodiment of this invention, various components of the energy storage system in the circuit of the converter can be configured in a modular manner to facilitate maintenance and replacement. Since the energy storage system replaces the original Chopper resistor and stores the discharged electric energy, it can be used to power the wind turbine and the converter itself, or to power the wind turbine for soft start.

[0043] In this embodiment, the main control system of the wind turbine generator set also has a power module on the other control side, which is connected to the connection line between the bidirectional chopper and the energy storage system through the auxiliary transformer, reactor and inverter connected in sequence. A filter module is also connected between the auxiliary transformer and the reactor; switches and fuses are also provided on the connection loop between the main control system and the energy storage system.

[0044] When there is enough electric energy stored in the energy storage system, when the electric energy circuit between the energy storage system and the main control system is connected, the stored DC power can be converted into AC power. After filtering through the reactor and filter module, it is converted into 400V AC power supply by the auxiliary transformer, which can be used as the power source for the main control system inside the wind turbine set, supporting lighting system and other equipment in the event of sudden shutdown.

[0045] As a preferred embodiment of this embodiment, the battery in the energy storage system adopts a fully solid-state energy storage battery, the corresponding battery cluster adopts a full series connection mode, and the charge and discharge rate is set to 0.5 C. On this basis, the capacity of the energy storage system is 20% of the capacity of the wind turbine set, and the energy storage system has a factory state of charge (SOC) of 65%, thereby ensuring the power required for the wind turbine black start.

[0046] The energy storage system is also equipped with a battery management system. The safety signals in the battery management system have two sets of signal lead-out points, one set is connected to the main control system, and the other set is connected to the fan switch cabinet. The battery management system is used to collect the temperature, voltage, and current data of the energy storage system and send them to the main control system. The main control system is used to set the control logic of the energy storage control system based on the received data.

[0047] The energy storage control system operates according to the battery status of the energy storage system under the control logic; the energy storage control system is used to connect the power module in the electrical system and the energy storage system's electric energy circuit when the energy storage system is in a power-deficient state, so as to realize the storage of discharged energy in the energy storage system; the energy storage control system is also used to disconnect the power module in the electrical system and the energy storage system's electric energy circuit when the energy storage system is in a fully charged state, and simultaneously connect the power module in the electrical system and the main control system's electric energy circuit, so as to realize the direct conversion of discharged energy for use by the main control system and its supporting equipment.

[0048] Moreover, in the event of an unexpected abnormal situation, the energy storage control system is also used to simultaneously connect the energy storage system to the power circuits of the power modules in the main control system and the electrical system to achieve power supply in the event of an unexpected abnormal situation.

[0049] Based on the system design of the above converter, the working principle of the converter is introduced as follows:

[0050] In an offshore environment, a traditional wind turbine needs to carry a diesel generator when it is started for the first time, but the inverter of this embodiment can realize the black start of the unit through the initial power in the energy storage system, and complete the calibration work related to the wind turbine dynamics and grid-connected debugging before the grid power is delivered. After the grid is connected, it can be connected to the grid once, thereby improving the success rate of the wind turbine to the grid once.

[0051] In a microgrid environment, the power grid fluctuates greatly, and wind turbines are prone to high and low voltage crossing. At this time, due to the power grid feeding or the generator maintaining the original power output, the electric energy on the converter circuit should be discharged through the Chopper resistor, which will cause a large waste of energy. After the energy storage system replaces the Chopper resistor in this embodiment, the electric energy that should be discharged is converted into voltage through a bidirectional chopper, and the all-solid-state energy storage battery of the energy storage system converts this part of the electric energy into chemical energy and stores it, thereby providing emergency power for the main control system, lighting, etc. of the wind turbine itself during shutdown. In addition, the stored electric energy can be reversely supplied to the converter power module, which also replaces the UPS function in the traditional converter, and can provide emergency power for the converter when the unit is shut down. At the same time, the stored electric energy can also be fed to the DC busbar to increase the voltage of the converter circuit, realize soft start after the wind turbine is shut down, and greatly improve the utilization rate of energy.

[0052] Example 2

[0053] Based on Example 1, this example introduces the preferred overall product of the energy storage integrated converter. In addition to the core functional characteristics of the system in terms of electrical and energy storage, the supporting system equipment of the converter is crucial to its safety and is therefore indispensable.

[0054] like Figure 3 As shown, the converter also includes a cabinet, and the electrical system and energy storage control system are installed inside the cabinet. Various related cables can be connected from the cabinet to the locations of nodes such as the power grid, generator, and wind turbine control system. A cabinet door is provided on the front of the cabinet, and various components and equipment of the system can be accessed through the cabinet door for operation. An energy storage backpack is installed in a hanging manner on the back of the cabinet, and the energy storage system is installed inside the energy storage backpack.

[0055] In this embodiment, due to the particularity of a large number of batteries in the energy storage system, a polypropylene board (i.e., PP board, which has a fire retardant effect) with a thickness of not less than 1 cm needs to be laid between the energy storage backpack and the converter cabinet. The cables between the energy storage backpack and the cabinet pass through the cable glands provided on the polypropylene board to achieve the connection between the energy storage backpack and the cabinet; preferably, the cable surfaces before and after the cable glands are coated with fire retardant paint.

[0056] For the water cooling system, this embodiment is introduced as follows: the water cooling system includes a heat exchange pump station, a heat dissipation pipeline and a radiator; the heat exchange pump station is installed inside the cabinet to provide power for the coolant in the heat dissipation pipeline; the heat dissipation pipeline is used to provide a fluid passage for the coolant, and the coolant realizes the heat exchange between the power module of the electrical system and the battery of the energy storage system; the heat dissipation pipeline is connected to the radiator, and the radiator is installed outside the cabinet to dissipate the heat carried by the coolant through natural air cooling.

[0057] As for the fire protection system, this embodiment is described as follows: the fire protection system includes 4 smoke sensors and 1 10 kg aerosol automatic fire extinguishing device. One smoke sensor is installed inside and outside the converter cabinet, and inside and outside the energy storage backpack; the aerosol automatic fire extinguishing device is arranged on the top of the cabinet near the energy storage backpack. The device can be quickly activated when the initial smoke of the fire is detected, and the fire extinguishing agent is released to cover the entire cabinet and energy storage backpack area, thereby effectively suppressing the spread of the fire and achieving rapid fire extinguishing.

[0058] After the improvement of the above-mentioned supporting system equipment, the converter of this embodiment, as an integrated product, improves the overall performance and reliability of the wind power generation system unit, promotes the innovative development in the field of clean energy, successfully reduces energy waste, and improves the utilization rate of electric energy.

Claims

1. A novel energy storage integrated converter for wind power generation in a microgrid environment, characterized in that: The converter includes an electrical system, a water cooling system, a fire protection system, an energy storage system and an energy storage control system, wherein: One end of the electrical system is connected to the generator of the wind turbine, and the other end is connected to the external power grid. The electrical system is used to convert the electric energy generated by the generator into AC-DC-AC through the power module and then send it to the grid-side transformer for boosting and grid connection. The water cooling system is used to provide water cooling and heat dissipation for the electrical system and energy storage system during operation; The fire protection system is used to monitor the fire conditions at each system location of the converter and automatically extinguish the fire when a fire occurs; The energy storage system is connected to the power module in the electrical system, and at the same time, the main control system of the wind turbine is connected to the connection circuit between the energy storage system and the power module; the energy storage system is used to store the electric energy discharged by the power module, and provide the stored electric energy to the main control system in case of sudden abnormal conditions; The energy storage control system is connected to the energy storage system. The energy storage control system is used to monitor the electric energy storage situation of the energy storage system, and at the same time control the on and off of the electric energy circuit between the power module and the energy storage system and the main control system respectively.

2. The energy storage integrated converter according to claim 1, characterized in that: The converter also includes a cabinet, and the electrical system and the energy storage control system are both installed inside the cabinet; a cabinet door is provided on the front of the cabinet, and an energy storage backpack is installed on the back of the cabinet in a hanging manner, and the energy storage system is installed inside the energy storage backpack.

3. The energy storage integrated converter according to claim 1, characterized in that: Both ends of the power module of the electrical system are connected to the generator and the external power grid respectively through circuit breakers; starting from the motor side, the power module includes a rectifier and an inverter connected in sequence, with a DC busbar between the two; reactors are provided on the side of the rectifier and the inverter away from the DC busbar, and filter modules are connected between the two ends of the power module and the corresponding circuit breakers; a fuse is also connected in series in the circuit where the power module is located.

4. The energy storage integrated converter according to claim 3, characterized in that: The circuit breaker on the grid side of the power module is connected to the external grid through a corresponding transformer. A series fuse and a lightning protection module are also connected to the connection line between the circuit breaker and the transformer. The other end of the lightning protection module is grounded.

5. The energy storage integrated converter according to claim 2, characterized in that: The water cooling system includes a heat exchange pump station, a heat dissipation pipeline and a radiator; the heat exchange pump station is installed inside the cabinet to provide power for the coolant in the heat dissipation pipeline; the heat dissipation pipeline is used to provide a fluid path for the coolant, and the coolant realizes the heat exchange between the power module of the electrical system and the battery of the energy storage system; the heat dissipation pipeline is connected to the radiator, and the radiator is installed outside the cabinet to dissipate the heat carried by the coolant through natural air cooling.

6. The energy storage integrated converter according to claim 2, characterized in that: The fire protection system includes multiple smoke sensors and aerosol automatic fire extinguishing devices; the smoke sensors are installed in the inner and outer areas of the cabinet and the energy storage backpack respectively; the aerosol automatic fire extinguishing device is arranged on the top of the cabinet close to the energy storage backpack.

7. The energy storage integrated converter according to claim 2, characterized in that: A polypropylene plate is arranged between the energy storage backpack and the cabinet of the converter, and the thickness of the polypropylene plate is greater than or equal to 1 cm; the cables between the energy storage backpack and the cabinet pass through the cable gland arranged on the polypropylene plate to realize the connection between the energy storage backpack and the cabinet.

8. The energy storage integrated converter according to claim 1, characterized in that: The energy storage system is connected to the DC busbar of the power module in the electrical system through a bidirectional chopper, and switches and fuses are also provided on the connection line between the bidirectional chopper and the DC busbar.

9. The energy storage integrated converter according to claim 8, characterized in that: The main control system of the wind turbine is connected to the connection line between the bidirectional chopper and the energy storage system through the auxiliary transformer, reactor and inverter connected in sequence; a filter module is also connected between the auxiliary transformer and the reactor; switches and fuses are also provided on the connection loop between the main control system and the energy storage system.

10. The energy storage integrated converter according to claim 9, characterized in that: The energy storage system has a factory state of charge with a preset percentage value and is also equipped with a battery management system; the battery management system is used to collect temperature, voltage, and current data of the energy storage system and send them to the main control system, which is used to set the control logic of the energy storage control system based on the received data; The energy storage control system operates according to the battery status of the energy storage system under the control logic; the energy storage control system is used to connect the power module in the electrical system and the power circuit of the energy storage system when the energy storage system is in a power-deficient state, so as to realize the storage of discharged energy in the energy storage system; the energy storage control system is also used to disconnect the power circuit of the power module in the electrical system and the energy storage system when the energy storage system is in a fully charged state, and simultaneously connect the power circuit of the power module in the electrical system and the main control system, so as to realize the direct conversion of discharged energy to supply the main control system and its supporting equipment; In the event of an unexpected abnormal situation, the energy storage control system is also used to simultaneously connect the energy storage system to the power circuits of the power modules in the main control system and electrical system to achieve power supply in the event of an unexpected abnormal situation.

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