Large-scale distributed flexible wind, solar, storage, charging, and discharge, AC / DC hybrid system and control system based on energy cloud interconnection

Abstract

The present invention discloses a large-scale distributed flexible wind, solar, storage, charging and discharging, and mains AC / DC hybrid system and control system based on energy cloud interconnection, including complementary multi-megawatt battery energy storage converters and wind, solar and storage integrated systems, transformerless high-voltage direct-mounted battery energy storage power conversion systems, AC microgrids, and DC microgrids; high voltage, high power, and automatically adjustable voltage and power, smart grid and solar storage, charging and discharging, two-way complementarity, and uninterrupted power supply.

Description

Technical Field

[0001] The present invention belongs to the field of power transmission and distribution technology of the Internet of Things smart grid, and relates to a large-scale distributed flexible wind, solar, storage, charging, and discharge, and mains AC and DC hybrid system and control system based on energy cloud interconnection. Background Art

[0002] With the deepening of the dual carbonization process, DC distribution networks are making a strong comeback in the main grid. Distributed renewable energy storage systems, such as photovoltaic storage and charging / discharging, are experiencing rapid growth. Hybrid AC / DC power generation and distribution will undoubtedly be the norm for future power distribution systems. Solar storage and charging / discharging systems are becoming a research hotspot, aiming to improve the user-friendliness of photovoltaic systems and regulate grid power quality. Large-scale distributed flexible solar storage and charging / discharging systems based on IoT-based dual carbon assessment are also becoming research hotspots. However, current solar storage and charging / discharging systems still face many challenges and technical difficulties that need to be addressed.

[0003] Photovoltaic (and wind power) systems are significantly affected by weather. System output decreases significantly when sunlight is poor for photovoltaic systems, and when wind power is weak or even flat. This can cause power instability or even blackouts for off-grid photovoltaic systems. Furthermore, large-scale grid-connected power generation systems often fail to connect to the grid due to issues like anti-islanding, large system fluctuations, and the need to obtain grid connection permits. This significantly impacts the economic efficiency and stability of photovoltaic (and wind) power generation systems.

[0004] The existing ratio of distributed photovoltaic power stations to energy storage capacity is 5:1. In principle, the government requires a curtailment rate below 5% and annual energy storage power consumption within a planned 100-hour period. To reduce the risk of curtailment, distributed photovoltaic power generation currently faces major challenges: inadequate converter power. Building users only have 5kW-8kW, commercial and industrial users no more than 250kW, and voltage levels below 900V. Furthermore, the energy storage battery capacity is too small and has a short lifespan (4-5 years). The cost recovery for photovoltaic, storage, and charging / discharging systems takes 5-6 years, and the battery needs to be replaced before the energy storage charging station has even recovered, making profitability even more challenging. This system cannot meet emergency power needs, with power supply durations exceeding two hours. A single Powerwall energy storage battery has a capacity of 13.5kWh and a continuous output power of 5kW. PV alone cannot adequately supply electricity to buildings, commercial, and industrial users. At present, the power of a single DC fast charging pile powered by energy storage charging stations is more than 60kW. The operation of a DC fast charging pile is roughly equivalent to the electricity consumption of 20 to 30 households, which has a great impact on the power grid. The power and voltage of the existing distributed photovoltaic storage and charging systems cannot be expanded, and the temperature rise limit is that the continuous power supply does not exceed 2.5 hours. In the entire power supply period, the energy storage system accounts for less than 2% of the system, which is far from enough to meet the continuous power consumption of existing electrical equipment.

[0005] A photovoltaic, storage, and charging / discharging system is centered around an integrated charging station—a photovoltaic power generation system, energy storage batteries, and charging piles. The system also includes bidirectional energy metering and distribution, which uses the stored energy in the storage batteries to release it to buildings, industrial, and commercial electrical equipment, and distribute electricity. These five components form a microgrid. Photovoltaic power is generated and stored in the storage batteries. When needed, the storage batteries supply the energy to the charging piles, building users, and industrial and commercial electrical equipment. Through the photovoltaic, storage, and charging system, clean solar energy is transferred to the vehicle's power battery for driving and use. Depending on demand, the photovoltaic, storage, and charging / discharging integrated charging station can operate in both grid-connected and off-grid modes. When connected to the grid, the integrated photovoltaic, storage, and charging station not only receives energy from the photovoltaic panels, but also charges the energy storage batteries when electricity prices are low and discharges them when prices are high. This reduces charging costs, reduces peak loads, and offsets the intermittent nature of solar power generation. In the event of a grid outage, the photovoltaic, storage, and charging system can operate in an off-grid mode for emergency charging of new energy vehicles, building users, industrial and commercial electrical equipment, and fire safety scenarios. Because photovoltaic charging and discharging systems cannot generate electricity at night or on rainy days, distributed photovoltaic and energy storage systems cannot continuously supply electricity to building users, industrial and commercial electrical equipment, especially charging stations and emergency power. In addition to self-use of photovoltaic power generation and supplying surplus power to the grid, there are many situations where the grid is needed to power energy storage batteries, converters, and energy storage to ensure continuous power supply to converter systems and other equipment.

[0006] Multilevel inverters are very popular for medium- and high-power conversion because they can generate high voltage amplitudes with low output harmonics while using devices with smaller voltage ratings. This is why diode-clamped multilevel inverters have been developed. Clamping diodes share unequal voltages during each switching state. Each leg requires 12 diodes to maintain equal voltage distribution across them. The power dissipation of 12 diodes per phase is significant. The unbalanced voltage across the DC link capacitors of diode-clamped multilevel inverters generates low-order harmonics in the output voltage and increases voltage stress on the switching devices, potentially causing permanent damage. After medium- and high-power conversion, the three-phase voltages of multilevel inverters experience unbalanced voltage and power at the load and grid, impacting inverter efficiency and lifespan.

[0007] Uneven voltage distribution in the capacitors of existing multilevel inverters can damage diodes and switching devices and generate output voltage harmonics. To overcome capacitor drift, a transformer can be used in the front end, with its isolated secondary windings supplying power to the individual capacitors via a diode bridge rectifier. However, transformers make the system heavier, more expensive, and less efficient. Capacitor voltage imbalance can also be corrected by adding DC offset and third harmonic components to the modulation waveform combined with the switching circuitry. This additional hardware increases power circuit complexity and system cost, especially at high power levels. To address the voltage drift problem in classic diode-clamped multilevel converters and some control schemes, a cost function based on the average value of the capacitor voltage and the DC link intermediate branch current is used to achieve voltage balancing using support vector machines (SVMs). These methods also require reference to the sector in which the space vector falls during each sampling cycle, requiring significant resources and computational effort to determine the frequency, phase, and amplitude of each phase. This makes the system more complex and incompatible with smart grid and IoT integration. High-precision energy metering and carbon neutrality assessment are therefore impossible for connected loads and consumers. Existing SVM vector-controlled converters suffer from high power consumption, frequency offset, low inverter efficiency, and low precision. They also fail to meet the real-time requirements of smart grids, solar-storage charging and discharging systems integrated into smart grids, energy metering, and carbon neutrality assessments. They are unable to avoid spectrum leakage, grid rot, phase shift, and frequency band aliasing, and are incapable of estimating harmonic and interharmonic frequencies. Existing technologies cannot bidirectionally measure the energy of different items across smart grids, inverters, energy storage, converters, charging stations, building users, and industrial equipment.

[0008] The existing solar (wind) storage and charging and discharging system is container-type. The development of high-voltage, ultra-high-power, multi-battery hybrid solar (wind) storage and charging and discharging system is a future trend and hot spot. However, it causes fluctuations in the DC bus during joint operation, affecting the life and stability of the energy storage system.

[0009] Renewable energy generation capacity will account for over 50% of my country's total installed power capacity. To mitigate the volatility and intermittency inherent in renewable energy sources like wind and photovoltaics, large-scale, high-percentage, and user-friendly smart grids and the Internet of Things (IoT) will enhance the capacity to absorb and store renewable energy. To ensure a stable power supply, seamless power supply from wind, solar, storage, charging, and discharge systems, coupled with smart grids, is essential. Flexible power system regulation, interactive integration, and complementary integration are essential. This will build a new, clean, environmentally friendly, and zero-carbon smart energy system, centered around renewable energy. Summary of the Invention

[0010] In order to solve the above problems, an embodiment of the present invention provides a large-scale distributed flexible wind, solar, storage, charging and discharge, and AC / DC hybrid system based on energy cloud interconnection, which has high voltage, high power, and automatically adjustable voltage and power. The smart grid and solar storage, charging and discharge complement each other in a two-way manner, providing uninterrupted power supply.

[0011] Another object of the present invention is to provide a control system for a large-scale distributed flexible wind, solar, storage, charging, and discharge AC and DC hybrid system based on energy cloud interconnection.

[0012] The technical solution adopted by the present invention is a large-scale distributed flexible wind, solar, storage, charging and discharging AC and DC hybrid system based on energy cloud interconnection, including complementary multi-megawatt battery energy storage converters and wind, solar and storage integrated systems, transformerless high-voltage direct-mounted battery energy storage power conversion systems, AC microgrids, and DC microgrids; wherein,

[0013] The multi-megawatt battery energy storage converter is used to realize multi-megawatt wind and solar power generation, energy storage and bidirectional charging of multi-megawatt batteries;

[0014] The wind-solar-storage integrated system is used to integrate a multi-megawatt photovoltaic battery energy storage converter and a multi-megawatt wind battery energy storage converter into the same system to realize energy storage, bidirectional charging and discharging functions;

[0015] The transformerless high-voltage direct-mounted battery energy storage power conversion system is used to achieve flexible switching between low-voltage and high-voltage systems and directly access the high-voltage power supply system through transformerless high-voltage direct-mounted battery energy storage power conversion;

[0016] The AC microgrid and DC microgrid are used to flexibly access the smart grid to achieve mixed use of AC and DC mains power.

[0017] Another technical solution adopted by the present invention is a control system for a large-scale distributed flexible wind, solar, storage, charging, and discharge utility power AC / DC hybrid system based on energy cloud interconnection, including a smart grid voltage controller, a battery voltage controller, a pulse modulator, and a hybrid energy storage platform;

[0018] The smart grid voltage controller includes a comparator, a compensator, and a negative limiter. When the battery voltage V bat The minimum acceptable battery voltage corresponding to the battery's safe SOC When the difference is greater than 0, the comparator output is set to the reference voltage of the first AC mains grid and the second AC mains grid. When the battery voltage V bat Less than The battery is at low SOC and does not have enough power to supply the total load. The comparator outputs the reference voltage of the DC or AC microgrid. Set the reference voltage Set to unload voltage Vshat , to trigger the load reduction system; DC microgrid or AC microgrid reference voltage Generate output voltage corresponding to the actual battery SOC; unimportant loads in the DC or AC microgrid are removed, saving resources for sensitive loads;

[0019] The grid voltage V output by the diode clamped multi-level two-stage topology circuit grid Reference voltage of DC or AC microgrid Compare, The maximum value selected by the battery-voltage source converter is greater than the maximum value of the controlled grid voltage; the maximum value is input to the grid voltage compensator G C-grid , compensator G C-grid The output is sent to the negative limiter; in grid-connected mode, The generated signal is limited to zero by the negative limiter; in this case, the battery voltage controller controls the battery charging process, i.e., the voltage control loop;

[0020] When the distributed photovoltaic storage charging and discharging station and the distributed wind storage charging and discharging station generate insufficient power, the voltage control loop will set the battery reference voltage By controlling the direction to positive rotation and the negative limiter to zero, the control combination outer voltage loop generates the converter reference voltage Provides compensation power for battery discharge; converter reference voltage and battery voltage set point voltage Comparison, output battery reference voltage

[0021] The battery voltage controller includes a comparator, a battery voltage compensator G C-bat , battery current limiter, battery reference voltage output by smart grid voltage controller With the battery voltage V bat Compare, when the comparison result is greater than 0, the output voltage difference is sent to the battery voltage compensator G C-bat ;Battery voltage compensator G C-bat The output end is connected to the battery current limiter, and the charging selects the maximum battery charging current Discharge selection maximum discharge current Battery current limiter outputs battery reference current

[0022] Battery Current I in a Bidirectional Buck-Boost DC / DC Interface Circuit bat and battery reference current As the input current of the pulse modulator, the equivalent impedance of the battery input side R L The inductor L generates the inductor current rising or falling slope compensation F b, the resistor R0 and capacitor C0 of the output filter generate the inductor current rising or falling slope compensation F0 input pulse modulator;

[0023] The battery bidirectional buck-boost DC / DC interface unit and the wind-solar-storage integrated system are connected to the input of the pulse modulator through the corresponding switch, sending the battery voltage I bat To pulse modulator; grid reference voltage Grid compensation output voltage output by the pulse modulator Both are input to the first comparator. When the difference is negative, the first comparator outputs the voltage difference and starts the grid voltage compensator G C-grid , through the grid voltage compensator G C-grid Compensated voltage, battery output reference voltage Battery input combined output disturbance voltage Both are input to the second comparator, and the second comparator outputs the maximum voltage difference to the battery voltage compensator G C-bat Compensation, battery voltage compensator G C-bat Output compensation current, inductive disturbance current in battery model Input to the third comparator, the third comparator outputs the current difference; the current difference, the inductor current rise or fall slope compensation F b , the inductor current rising or falling slope compensation F0 are input to the fourth comparator, and the fourth comparator outputs the battery current rising or falling slope compensation F m ; Where D represents the steady-state duty cycle of the inductor, T s is the period of the gate pulse, M s represents the synthetic slope for current slope compensation, L represents the inductance, and D' represents the steady-state duty cycle of the capacitor;

[0024] Based on the battery current rising or falling slope compensation F m Determine the current duty cycle Current transfer function G from input to inductor L id ; Output disturbance current generated by the output filter's resistor R0 and capacitor C0 Enter to Z in sequence L , Z i , Z L is the current transfer function from the open-loop output current i0 to the inductor L, Z i is the transfer function from the open-loop output current i0 to the input voltage;

[0025] Transfer function Z L , G id The output values ​​of are input to the fifth comparator, and the maximum value of the comparison is used as the output disturbance current of the inductor L Input to G bi, G bi is the transfer function from inductor current to input voltage, transfer function Z i The output value, transfer function G bi The output values ​​are input to the sixth comparator, and the maximum value of the comparison is used as the output synthetic disturbance voltage of the battery The battery output side R0 and C0 are both input to G 0b , G 0b is the voltage transfer function from input to output G 0b , transfer function G 0b The output value and the open-loop output resistance Z0 are input to the seventh comparator, Z0 does not include the load resistance; the voltage and transfer function G when the current command duty cycle is greater than 50% 0b The output value is compared, and the maximum value is used as the battery voltage and current peak slope to synthesize the compensation double loop control grid compensation output disturbance voltage Based on the disturbance voltage during different disturbance periods Regulate the grid voltage according to the discharge mode.

[0026] The beneficial effects of the present invention are:

[0027] 1. The power supply circuit system provided by the present invention has high voltage (480-2000V), high power (250KW-630KW), and the voltage and power are automatically adjustable. The smart grid and the photovoltaic storage charging and discharging are bidirectionally complementary, and the smart grid and photovoltaic energy storage power supply are flexibly adjusted to provide long-term and low-cost uninterrupted power supply to ordinary loads, major loads, charging stations, and charging piles.

[0028] 2. The present invention uses distributed photovoltaic charging and discharging stations to provide long-term uninterrupted emergency power supply to energy storage power charging piles, building users, smart grids, and industrial users' electrical equipment, and flexibly adjusts them so that photovoltaic power generation can provide high-proportion and low-cost power to ordinary loads, major loads, and smart grids for a long time.

[0029] 3. The present invention solves the problems of uneven voltage distribution in the capacitors of existing multi-level high-power inverters, which damages diodes and switching devices, generates output voltage harmonics and capacitor voltage, frequency drift, multiple power devices, high power consumption, and low inverter efficiency.

[0030] 4. The present invention realizes the access of renewable energy (photovoltaic storage and charging and discharging system) to smart grid and Internet of Things with high precision and high power quality. The power can be controlled through voltage control, neutral line, fault ride-through and anti-islanding control system. Through high-precision electricity meter, it realizes the measurement of renewable energy dual carbon evaluation, multi-directional electricity with different rights and intelligent identity recognition.

[0031] 5. The integrated control platform for multiple control links of light (wind) will combine the variable time constant energy storage control link that smoothes the fluctuations of wind and light power, and the link for optimizing the distribution of different types of energy storage output. While ensuring the service life of the lead-acid battery, it will maximize the use of supercapacitor energy storage equipment to absorb high-frequency components, and use lithium iron phosphate battery energy storage equipment to suppress the fluctuation of the DC bus. The wind storage energy storage system adopts SOC+power-voltage and the light storage adopts power-voltage control mode to ensure hybrid output, which can meet the requirements of the given target power, can cope with the power fluctuations at the grid connection point caused by large-scale wind and solar grid connection, and cause the fluctuation of the DC bus of the energy storage device, reduce the number and depth of battery charging, extend the battery life, give full play to the complementary advantages of energy-type and power-type energy storage equipment, and make the energy storage system operate stably under weak power grids.

[0032] 6. DC and AC microgrid systems constitute a crucial component of smart grids, effectively enabling grid-side power transfer and peak-shaving. Microgrid technology adds an energy storage component to the traditional power system's production model, making the previously rigid system more flexible and enabling more efficient operation of the entire grid. During peak demand periods, microgrids can provide energy to the load; during off-peak demand periods, they can store excess energy within the grid. Furthermore, in smart grid systems, many distributed power sources (DGs) rigidly transmit their generated energy to the grid, leaving the grid to passively absorb it. Therefore, the power quality of DG output significantly impacts the grid system. Adding microgrids effectively regulates active and reactive power within the system, acting as a regulator for improving grid power quality. Microgrids include a variable time constant energy storage control component to smooth wind and solar power fluctuations, an optimized output allocation component for different types of energy storage, a power-voltage control component to enhance the stability of weak grids, and a comprehensive integrated monitoring system for multiple control components. This effectively improves the lifespan, utilization, and operational stability of energy storage systems.

[0033] 7. This invention proposes a transformerless, high-voltage, direct-mounted battery energy storage power conversion system. Using modular power electronic conversion technology, a large battery stack is divided into multiple battery packs consisting of series-connected battery cells. These systems perform bidirectional (high-voltage / low-voltage) charge and discharge control and charge state balancing, eliminating circulating currents and their associated losses, significantly improving system safety. Because modular technology eliminates the need for power frequency transformers and achieves high- and low-voltage compatibility, it significantly reduces costs. The reduction in power transistors significantly reduces the power supply ramp-up and power consumption of ultra-high power systems, reduces the switching frequency of the converter, and suppresses circulating currents in the battery stack, resulting in a 10% improvement in charge and discharge cycle efficiency. The increased capacity of a single PCS (Power Conversion System) significantly simplifies the structure of ultra-large energy storage power stations, increasing dynamic response speed from seconds to tens of milliseconds. Furthermore, because the PCS replaces the battery management system's cell balancing tasks, the cost of the battery management system is reduced by 80%. This achievement allows the capacity of a single PCS to be increased from 500kW to 43MW, improving efficiency by 3%.

[0034] 8. A high-gain energy storage coupler that couples battery packs to the DC bus of wind / photovoltaic converters, addressing multi-link energy storage control and integrated platform technology for large-scale wind / solar grid integration. This high-gain energy storage coupler, which couples battery packs to the DC bus of wind and photovoltaic converters, integrates the energy storage converter with the wind converter and photovoltaic inverter based on an invented multi-level inverter and a bidirectional converter with a series saturated inductor. This achieves efficiencies of 98.9% for the wind and 98.5% for the photovoltaic couplers. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 It is a structural topology block diagram of an embodiment of the present invention.

[0037] Figure 2 4 is a system diagram of a distributed storage and charging station in an embodiment of the present invention.

[0038] Figure 3 This is a diagram of the distributed solar (wind) storage, charging and discharging flexible electric energy (dual carbon) evaluation and control system in an embodiment of the present invention.

[0039] Figure 4 It is a schematic diagram of a bidirectional charging and discharging multiple megawatt-class battery energy storage group in an embodiment of the present invention.

[0040] Figure 5a This is a topological diagram of a 5-level DC voltage-equalizing multi-phase chopped-wave optical storage, charging, and discharging circuit in an embodiment of the invention.

[0041] Figure 5b The invention provides a bidirectional buck-boost DC / DC circuit for interfacing a DC bus (DC microgrid) with a battery.

[0042] Figure 5c This is an embodiment of the invention. This is a topology diagram of the light storage charging and discharging circuit of the transformerless high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion system in the embodiment of the invention.

[0043] Figure 5d yes Figure 5a Diagram of the graded shutdown structure of the medium-level 5-level DC equalized voltage multi-phase chopped wave optical storage and charge-discharge circuit.

[0044] Figure 5e yes Figure 5c Diagram of the hierarchical shutdown structure of the photovoltaic charging and discharging circuit of the transformerless high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion system.

[0045] Figure 6 Schematic diagram of a bidirectional buck-boost DC / DC battery interface between a PCS and a battery cabinet in an embodiment of the present invention.

[0046] Figure 7 Schematic diagram of the topology circuit of the intelligent management controller for solar energy storage charging and discharging in an embodiment of the present invention.

[0047] Figure 8a It is a schematic diagram of a dual-loop control system consisting of a voltage loop and an additional internal current loop for a battery pack DC and a smart grid storage and charging / discharging converter according to an embodiment of the present invention.

[0048] Figure 8b It is a schematic diagram of a master-slave integrated flexible wind-solar storage-charging-discharging integrated platform for battery pack DC and smart grid (photovoltaic DC transmission) storage-charging-discharging converters in an embodiment of the present invention.

[0049] Figure 9 yes Figure 7 Schematic diagram of the waveforms of the three stages of solar storage charging and discharging.

[0050] Figure 10 is the Bode plot of G bi under minimum and maximum discharge current conditions in Figure 8.

[0051] Figure 11 is the Bode plot of G bi under minimum and maximum discharge current conditions in Figure 8.

[0052] Figure 12 This is a compensation diagram of the working principle of a large-scale distributed flexible photovoltaic storage charging and discharging AC / DC hybrid system for energy cloud interconnection according to an embodiment of the present invention.

[0053] Figure 13 This is a simulation curve of the remaining energy SOC of a high-frequency battery in a bidirectional charging and discharging megawatt-class battery energy storage in an embodiment of the present invention.

[0054] Figure 14 This is a simulation curve of the remaining energy SOC of a low-frequency battery in a bidirectional charging and discharging megawatt-class battery energy storage in an embodiment of the present invention.

[0055] Figure 15 This is a simulation curve of high-frequency battery charge and discharge current for bidirectional megawatt-class battery energy storage in an embodiment of the present invention.

[0056] Figure 16 This is a simulation curve of the high-frequency battery terminal voltage of a bidirectional charging and discharging megawatt-level battery energy storage in an embodiment of the present invention.

[0057] Figure 17 This is a simulation curve of low-frequency battery charge and discharge current for bidirectional megawatt-class battery energy storage in an embodiment of the present invention.

[0058] Figure 18 This is a low-frequency battery terminal voltage simulation curve for bidirectional charging and discharging of megawatt-class battery energy storage in an embodiment of the present invention.

[0059] Figure 19 yes Figure 5c The structure diagram of the intelligent control and management system of the photovoltaic storage charging and discharging circuit of the transformerless high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion system in the embodiment of the present invention. DETAILED DESCRIPTION

[0060] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0061] A large-scale distributed flexible wind, solar, storage, charging and discharge, AC and DC hybrid system based on energy cloud interconnection, such as Figure 1 As shown, it includes complementary multi-megawatt battery energy storage converters and wind-solar-storage integrated systems, transformerless high-voltage direct-mounted battery energy storage power conversion systems, AC microgrids, and DC microgrids; the AC microgrids and DC microgrids can be flexibly connected to the smart grid to achieve mixed use of AC and DC mains power.

[0062] The battery energy storage converter and the wind, solar and storage integrated system complement each other and achieve the industry's maximum single-machine power of 3.2MW; the transformerless high-voltage direct-mounted battery energy storage power conversion system realizes power supply in the high-voltage field, saving high-voltage transformers to a great extent; the DC microgrid of the low-voltage distributed mains DC-AC hybrid flexible solar storage charging and discharging system in the present invention plays the role of lowest circuit cost, compatible with flexible access to the smart grid, realizing mains AC-DC hybrid, low cost, full-field coverage, high-power power supply, and achieving the effect of uninterrupted power supply.

[0063] The smart grid includes a pair of parallel-arranged first AC mains grid and second AC mains grid. The first AC mains grid supplies power to the first AC bus, the second AC mains grid or the distributed flexible photovoltaic storage charging and discharging station supplies power to the generator, and the generator output end and the second AC mains grid supply power to the second AC bus; the distributed flexible photovoltaic storage charging and discharging station supplies power to the first AC bus through the AC microgrid, and the distributed flexible photovoltaic storage charging and discharging station is used for emergency power supply after the AC mains power is cut off.

[0064] An AC microgrid of a low-voltage distributed mains DC-AC hybrid flexible photovoltaic storage charging and discharging system, comprising a first AC bus, a second AC bus, and a third AC bus;

[0065] The first AC bus is connected to the first AC mains grid and the second AC mains grid through the first automatic transfer switch. The first AC bus is connected to the first DC bus and the second DC bus respectively through corresponding rectifiers. The first AC bus is connected to the energy storage components (battery cabinet and PCS cabinet) through the rectifier. At the same time, the first AC bus is connected to the motor room of the power station. The PCS system is connected to the first DC bus and the second DC bus through the rectifier and the smart meter ( Figure 1 The first AC bus supplies power to the first DC bus through a rectifier; the energy storage component supplies power to multiple DC buses, and multiple DC buses are connected to multiple groups of DC charging piles, load DC distribution cabinets, communication control cabinets and fire cabinets.

[0066] The input end of the second AC bus is connected to the generator set through the second automatic transfer switch, the generator set is connected to the first AC city grid and the second AC city grid through the first automatic transfer switch, the first AC city grid and the second AC city grid are switched through the third automatic transfer switch, and the second automatic transfer switch is connected to the output end of the distribution transformer on the second AC city grid; the common point output end of the first AC city grid and the second AC city grid is connected to the distribution transformer; the output end of the second AC bus is connected to the AC load; the AC load includes a lithium charger, an AC charging pile, n+1 groups of AC electrical control cabinets and multiple groups of communication cabinets, etc. The lithium charger and AC charging pile are used to charge electric vehicles.

[0067] The third AC bus is connected to multiple megawatt-class wind converters (such as the first wind converter and the second wind converter); the third AC bus is connected to the first AC bus via a fourth automatic transfer switch ( Figure 1 Not expressed in); the third AC bus passes through the rectifier ( Figure 1 (not shown) connected to a DC microgrid to provide power; multiple megawatt-class wind turbine converters power multi-megawatt-class battery energy storage converters;

[0068] The first AC bus, the second AC bus and the third AC bus are all connected to the DC DG through the DC / AC conversion module, connected to the AC DG through the AC / AC conversion module, connected to the AC energy storage through the AC / AC conversion module, and connected to the DC energy storage through the DC / AC conversion module; the output ends of the first AC bus, the second AC bus and the third AC bus are all connected to the load through the load controller; the output ends of the first AC bus, the second AC bus and the third AC bus are connected to the U, I measurement modules.

[0069] The DC microgrid of the low-voltage distributed mains DC-AC hybrid flexible photovoltaic storage charging and discharging system includes a first DC bus and a second DC bus; the first DC bus is connected to the PCS system, and the battery cabinet is connected to the PCS and the first DC bus respectively through a bidirectional buck-boost DC / DC interface circuit to achieve DC power supply; the first DC bus is connected to a DC meter, a communication cabinet and a fire cabinet, and multiple DC meters are connected to the corresponding DC piles and DC cabinets.

[0070] The second DC bus is connected to multiple megawatt-class multi-stage energy storage battery packs in the distributed wind storage charging and discharging station through a bidirectional buck-boost DC / DC interface circuit;

[0071] The first and second DC buses are connected via a sixth automatic reversing switch (not shown in the figure); the first and second DC buses are connected to the DC load, AC load, and AC energy storage, respectively, via corresponding DC / AC conversion modules; the first and second DC buses are both connected to the DC energy storage module via the DC / DC conversion module. The outputs of the first and second DC buses are both connected to the load via a load controller, and the outputs of the first and second DC buses are connected to U and I measurement modules. All electrical appliances are connected to the mains power line, the first AC bus, the second AC bus, the third AC bus, and the DC bus via a multi-position switch at a common access point, and are connected to the corresponding fire cabinet and communication control cabinet via communication lines. Each appliance must be connected to the mains power line, the first set of AC buses, the second set of AC buses, and the DC bus simultaneously.

[0072] When photovoltaic power generation is not carried out at night or on rainy days, the distributed wind storage charging and discharging station or the energy storage battery group on the distributed wind storage charging and discharging station supplies power to the general load and main load on the distributed photovoltaic storage charging and discharging station through the first AC bus, and supplies power to the load on the DC microgrid at the same time; when there is no wind, the energy storage battery group on the distributed wind storage charging and discharging station, the distributed photovoltaic storage charging and discharging station and the PCS supply power to the load on the DC microgrid.

[0073] The high-voltage AC grid hybrid flexible wind-solar storage charging and discharging system converts the power of the solar storage charging and discharging circuit into 4 transformer-free high-voltage direct-mounted battery energy storage power (see Figure 5c ) is connected to the municipal power grid; specifically:

[0074] The AC / DC module in the first wind power converter of the distributed wind storage charging and discharging station is connected to the transformerless high-voltage direct-mounted battery energy storage power conversion light storage charging and discharging circuit through a transfer switch ( Figure 1 Not expressed in), and then connected to the second AC mains public contact through switch S12;

[0075] The AC / DC module in the second wind power converter of the distributed wind storage charging and discharging station is connected to the transformerless high-voltage direct-mounted battery energy storage power conversion light storage charging and discharging circuit through a transfer switch ( Figure 1 Not expressed in), and then connected to the second AC mains public contact through switch S24;

[0076] The multi-quadrant converter of the distributed photovoltaic storage charging and discharging station is connected to the transformerless high-voltage direct-mounted battery energy storage power conversion photovoltaic storage charging and discharging circuit through the transfer switch ( Figure 1 Not expressed in), and then connected to the first AC mains public contact through switch S13;

[0077] The UPS inverter of the distributed photovoltaic storage charging and discharging station is connected to the transformerless high-voltage direct-mounted battery energy storage power conversion photovoltaic storage charging and discharging circuit through a transfer switch ( Figure 1 Not shown), and then connected to the first AC mains public contact through switch S14.

[0078] The first AC city grid public connection point and the second AC city grid public connection point are both located before the distribution transformer, realizing transformer-free high-voltage direct-mounted battery energy storage power conversion, photovoltaic storage, charging and discharging.

[0079] like Figure 1-2 As shown, the distributed flexible photovoltaic storage charging and discharging station includes a megawatt-class battery energy storage group (battery energy storage battery group) controlled by the Internet of Things perception coordination distribution system, an energy storage unit wave limiter, a multi-quadrant converter, and a UPS inverter. The multi-quadrant converter outputs power to general loads (ordinary loads) and smart grids, and the UPS inverter outputs power to important loads, providing emergency power supply when the grid is out of power. General loads and important loads are connected to the first AC bus through switches S6 and S7 respectively. When the multi-quadrant converter and UPS inverter are shut down for maintenance or fail, they are powered by the first group of AC buses.

[0080] When the AC mains fails or is under maintenance, the distributed photovoltaic storage charging and discharging station supplies power to the generator set through the smart grid and the first AC bus; when the AC mains fails / is under maintenance, or the generator set is powered off, the distributed photovoltaic storage charging and discharging station supplies power to the power station's motor room and multiple energy storage components (battery cabinets and PCS), and the PCS is a bidirectional energy storage converter. When the battery energy storage battery group and the smart grid are insufficient to supply power, the energy storage components (battery cabinets and PCS) will provide power to the megawatt-class battery energy storage group (i.e. Figure 1 Wind power battery energy storage battery pack and Figure 2 medium battery packs), smart grids, and generator discharge.

[0081] The first AC city grid and the second AC city grid are connected to a pair of distribution transformers with the same control parameters through a public access point. The pair of distribution transformers are controlled by a communication control cabinet ( Figure 1 The communication control cabinet in the n+1 control cabinet provides a power supply voltage equivalent to the DC bus for the first AC bus, the second AC bus, the generator set, the first automatic transfer switch, the second automatic transfer switch, and the third dual power switch. The DC distribution power supply voltage is ±280V, and the line voltage is 560V; 560VDC is compatible with 380VAC drive power and can be directly connected to 380VAC equipment; 280VDC is compatible with 220VAC drive power and can be directly connected to 220VAC lighting equipment (see Figure 1 ).

[0082] like Figure 2 As shown, the energy storage unit limiter includes a resistor R 01 , capacitor C 01 , bidirectional power tube SA9, inductor L 10 , bidirectional power tube SA8, capacitor C D , capacitor C B and switch S B ; The positive terminal of switch S2 is connected to resistor R 01 , the switch S2 port is connected to the negative pole and the capacitor C 01 , resistor R 01 and capacitor C 01 Series; the positive pole of the switch S2 port is connected to the C pole of the bidirectional power tube (IGBT) SA9, and the E pole of the bidirectional power tube SA9 is connected to the inductor L 10 Connection, inductance L 10 Connected to the positive pole of the battery storage battery, the bidirectional power tube SA9 and the inductor L 10 The connection node is connected to the C pole of the bidirectional power tube SA8, the E pole of the bidirectional power tube SA8 is connected to the negative pole of the battery energy storage battery, and a switch S is connected between the positive and negative poles of the battery energy storage battery. B , capacitor C B , switch S B , capacitor C BIn series, a capacitor C is connected between the positive and negative electrodes of the battery energy storage battery. D .

[0083] Three sets of series circuits consisting of resistors and switches are connected in parallel between the control electrode (G electrode) and the neutral line of the bidirectional power tube SA9 and the bidirectional power tube SA8, respectively. The voltage between the control electrode (G electrode) and the neutral line is 10V; the switch is connected to the IO port of the control chip MCU. It is normally turned on by the control chip MCU and is turned off by the MCU in an equal and time-sharing manner. The MCU intelligently disconnects the switch according to different temperatures, voltages, currents and environments.

[0084] The multi-quadrant converter and UPS inverter in the distributed photovoltaic storage charging and discharging station both adopt diode-clamped multi-level two-stage topology circuit, which has the functions of inversion and rectification; Figure 5a As shown, the diode clamped multi-level two-stage topology circuit includes the same and independent A, B, and C phase inverter / rectifier units, wherein the A phase inverter / rectifier unit includes an outer bridge arm clamp switch transistor S A1 , diode D A1 , S′ A1 、D' A1 , S′ A4 With the inner bridge arm clamp switch transistor S A2 , diode D A2 、S A3 , S′ A2 , D′ A2 , S′ A3 ;

[0085] The two ends and the series node of the series capacitors C1\C2\C3\C4 are connected in parallel to the five-level DC bus, outputting five equal-flow DC currents (i1, i2, i3, i4, i5). The first equal-flow DC current is divided into three paths, namely current i 1A , current i 1B , current i 1C The second path of DC current is divided into three paths: current i 2A , current i 2B , current i 2C , and so on, the fifth path of DC current is divided into three paths, namely current i 5A , current i 5B , current i 5C ;

[0086] Current i 1A SiC MOSFET transistor S connected to the A-phase inverter / rectifier unit A1 、S A4 The series circuit, current i 2A Enter the SiC MOSFET transistor S A2 、S A3The series circuit, current i 4A Enter the SiC MOSFET transistor S' A2 , S′ A3 The series circuit, current i 5A Enter the SiC MOSFET transistor S' A1 , S′ A4 Series circuit of diode D A1 Clamped on transistor S A1 、S A4 The series junction of diode D' A1 The reverse clamp is located on transistor S' A1 , S′ A4 The series junction of diode D A2 Clamped on transistor S A2 、S A3 The series junction of diode D' A2 The reverse clamp is located on transistor S' A2 , S′ A3 The series node of 3A Pass diode D A2 , diode D' A2 The series junction of transistor S' A2 、S A3 The series junction of the diode D A1 , diode D' A1 The series node connection of transistor S' A1 With transistor S A4 The connected midpoint outputs the A-phase AC current i A ;

[0087] Through the same circuit, the current i 1B Current i 5B Output B phase AC current i B , current i 1C Current i 5C Output C phase AC current i C .

[0088] like Figure 5a As shown, the 5-level DC voltage-equalizing (positive and negative levels) multi-phase chopped wave optical storage and charge-discharge circuit includes an energy storage battery group, which is composed of energy storage batteries Cell1 to Cell5 connected in series. Four series capacitors C1\C2\C3\C4 are connected between the positive electrode of the battery energy storage group Cell1 and the negative electrode of Cell5. The negative electrode of the battery energy storage group Cell5, the series node of two adjacent capacitors, and the positive electrode of the first-level battery Cell1 correspond to currents 0, 1, 2, 3, and 4 (the fourth DC path), respectively.

[0089] The series connection point of capacitors C1 and C2 is connected to the inductor end of the R1L1 filter through the connecting line Cel3, the resistor end of the R1L1 filter is connected to the emitter of transistor S1, and the collector of transistor S1 is connected to the fourth DC path; the series connection point of capacitors C3 and C4 is connected to the inductor end of the R3L3 filter through the connecting line Cel1, the resistor end of the R3L3 filter is connected to the emitter of transistor S3, and the collector of transistor S3 is connected to the fourth DC path; the emitter of transistor S3 is connected to the output of diode D33. The input end of the diode D33 is connected to the negative electrode of the fifth battery Cell5; the series node of the capacitors C2 and C3 is connected to the inductor end of the R2L2 filter through the connecting line Cel2, the resistor end of the R2L2 filter is connected to the emitter of the transistor S2, the resistor end of the R2L2 filter is connected to the output end of the diode D22, the emitter of the transistor S2 is connected to the output end of the diode D22, the collector of the transistor S2 is connected to the fourth DC path, and the input end of the diode D22 is connected to the connecting line Cel1.

[0090] The output terminal of the A-phase inverter / rectifier unit is connected to the middle point of R a L a Filtering, R a L a The filter output terminal is connected to the 5th current i 5A The middle point of the output terminal of the B-phase inverter / rectifier unit is connected to R b L b Filtering, R b L b The filter output terminal is connected to the 5th current i 5B Line, the middle point of the output terminal of the C-phase inverter / rectifier unit is connected to R c L c Filtering, R c L c The filter output terminal is connected to the 5th current i 5C Wire.

[0091] The first-level battery Cell1 and the fifth-level battery Cell5 are connected in series to form a positive-level energy storage battery pack with a rated voltage of 1500V (which can exceed 1500V to achieve high voltage voltage).

[0092] The number of switches in the 5-level DC voltage-equalizing (positive and negative levels) multi-phase chopped optical storage and charge-discharge circuit of the embodiment of the present invention is half that of the two-stage inverter in the prior art. It is more suitable for ultra-high voltage circuits not limited to 1500V. As the positive and negative levels of multi-phase chopped levels increase, the number of switches is reduced more significantly, and the level voltage develops more towards high voltage. The voltage stress at both ends of the switch is reduced. The switching loss is reduced. The control system and switching algorithm are greatly simplified. If the switch is accidentally turned on, the multi-phase chopped circuit will short-circuit, which will not affect the capacitor voltage and is more reliable. The reduction in semiconductor loss reduces the average temperature of the components. This leads to a significant reduction in the failure rate of the components. The redundancy in the switch combination can also be used to reduce the size of the chopped inductor; it can expand the configuration of more levels, reduce electromagnetic compatibility issues, reduce acoustic noise, limit voltage transients, etc.

[0093] The PCS system is connected to the battery cabinet through a bidirectional buck-boost DC / DC interface circuit, and the battery cabinet is connected to the DC microgrid through a bidirectional buck-boost DC / DC interface circuit; the batteries in the distributed wind storage charging and discharging station are connected to the DC microgrid through a bidirectional buck-boost DC / DC interface circuit; the battery energy storage battery pack of the distributed photovoltaic charging and discharging station is connected to the DC microgrid through a bidirectional buck-boost DC / DC interface circuit.

[0094] like Figure 5b As shown, the bidirectional buck-boost DC / DC interface circuit includes a battery, and the positive output line of the battery is connected in series with L and R L , L output terminals are connected to the first MOSFET tube (SA 10 ) of the S-pole, the second MOSFET tube (SA 11 ) is connected to the D pole of the first MOSFET tube (SA 10 ) is connected to the negative output line of the battery, and the second MOSFET tube (SA 11 ) is connected in series with a resistor R between the S pole of the battery and the negative pole of the battery. o , capacitor C o , the second MOSFET tube (SA 11 ) and the S pole of the resistor R o The output current between them is used as the positive pole of voltage and connected to the positive pole of microgrid (DC bus); capacitor C o The output current of the connection end of the negative output line of the battery is used as the negative voltage pole and connected to the negative pole of the microgrid (DC bus). A switch S is connected between the positive and negative poles of the battery. B and capacitor C B , switch S B With capacitor C B Series connection is used for pre-charging of the battery pack before charging, especially when it encounters over-discharge or the power grid is fast charging, to prevent damage to the battery pack.

[0095] The second MOSFET tube (SA 11 ) and the first MOSFET tube (SA 10 ) are connected in parallel between the control electrode and the neutral line, and three sets of series circuits of resistors and switches are connected. The voltage between the control electrode (G electrode) and the neutral line is 10V; the switch is connected to the IO port of the control chip MCU. It is normally turned on by the control chip MCU and turned off by the MCU in equal amounts. The MCU intelligently disconnects according to different temperatures, voltages, currents and environments.

[0096] Among them, L, R L represents the converter input filter, R o 、C o It is an output filter. Under different microgrid conditions, the battery operates in charging, discharging or floating charging mode, and the mode is managed according to the DC bus voltage at the BESS (battery energy storage system) coupling point.

[0097] Figure 5b The circuit in this example can be applied to Figure 2 The battery energy storage battery pack in Figure 5b The battery in the device.

[0098] like Figure 5c As shown, a transformer-free high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion light storage charging and discharging circuit includes an energy storage battery group, which is composed of energy storage batteries Cell1 to Cell5 connected in series. The negative end of the fifth battery Cell5 is connected to a fuse FU4, and the fuse FU4 is connected to the 0th DC circuit. The positive end of the first battery Cell1 is respectively connected to the A, B, and C three-phase circuits with the same structure. Taking the A phase circuit as an example, the positive input end of the first battery Cell1 is sequentially connected to the fuse FU1 and the switch S37. The two ends of the switch S37 are connected in parallel with a series circuit of a switch S36 and a pre-charging resistor R10. A series capacitor C1\C2\C3\C4 is connected between the output end of the switch S37 and the negative end of the fifth battery Cell5. The two ends and the series node of the series capacitors C1\C2\C3\C4 are respectively connected in parallel to a five-level DC bus, outputting five equalized DC currents (i 1A 、i 2A 、i 3A 、i 4A 、i 5A ), the negative electrode of the fifth battery Cell5, the series connection node of the two adjacent capacitors, and the positive electrode of the first-stage battery Cell1 correspond to the 0th, 1st, 2nd, 3rd, and 4th (fourth DC path) currents, which are i 5A 、i 4A 、i 3A 、i 2A 、i 1A .

[0099] Phase A DC current i 1A SiC MOSFET transistor S connected to the A-phase inverter / rectifier unit A1 、S A4 The series circuit, current i 2A Enter the SiC MOSFET transistor S A2 、S A3 The series circuit, current i 4A Enter the SiC MOSFET transistor S' A2 , S′ A3 The series circuit, current i 5A Enter the SiC MOSFET transistor S' A1 , S′ A4 Series circuit of diode D A1 Clamped on transistor S A1 、S A4 The series junction of diode D' A1 The reverse clamp is located on transistor S' A1 , S′ A4 The series junction of diode D A2 Clamped on transistor S A2 、S A3 The series junction of diode D' A2 The reverse clamp is located on transistor S' A2 , S′ A3 The series node of 3A Pass diode D A2 , diode D' A2 The series junction of transistor S' A2 、S A3 The series junction of the diode D A1 , diode D' A1 The series node connection of transistor S' A1 With transistor S A4 The connected midpoint outputs the A-phase AC current i A .

[0100] The series connection point of capacitors C1 and C2 is connected to the inductor end of the R1L1 filter through the connecting line Cel3, the resistor end of the R1L1 filter is connected to the emitter of transistor S1, and the collector of transistor S1 is connected to the fourth DC path; the series connection point of capacitors C3 and C4 is connected to the inductor end of the R3L3 filter through the connecting line Cel1, the resistor end of the R3L3 filter is connected to the emitter of transistor S3, and the collector of transistor S3 is connected to the fourth DC path; the emitter of transistor S3 is connected to the output of diode D33. The input end of the diode D33 is connected to the negative electrode of the fifth battery Cell5; the series node of the capacitors C2 and C3 is connected to the inductor end of the R2L2 filter through the connecting line Cel2, the resistor end of the R2L2 filter is connected to the emitter of the transistor S2, the resistor end of the R2L2 filter is connected to the output end of the diode D22, the emitter of the transistor S2 is connected to the output end of the diode D22, the collector of the transistor S2 is connected to the fourth DC path, and the input end of the diode D22 is connected to the connecting line Cel1.

[0101] Through the same circuit, the B-phase DC current at the positive terminal of the first battery Cell1 is converted into the B-phase AC current i B , the C-phase DC current at the positive terminal of the first battery Cell1 is converted into the C-phase AC current i C .

[0102] The neutral point of the output terminal of the A-phase inverter / rectifier unit is connected to a two-position switch S33, one of which is connected to R a L a Filter connection, R a L a The filter output is connected to the common point of the smart high-speed grid through fuse FU5 and connected to the A phase 0 DC circuit (i 5A The other side of the double-position switch S33 is connected to the negative electrode of the output terminal of the C-phase inverter / rectifier unit, forming a series connection of the A-phase circuit and the C-phase circuit.

[0103] The neutral point of the output terminal of the B-phase inverter / rectifier unit is connected to a two-position switch S34. One path of the two-position switch S34 is connected to R b L b Filter connection, R b L b The filter output is connected to the common point of the smart high-speed grid through fuse FU5 and connected to the B phase 0 DC circuit (i 5B The other side of the double-position switch S34 is connected to the negative electrode of the output terminal of the A-phase inverter / rectifier unit, forming a series connection of the B-phase circuit and the A-phase circuit.

[0104] The neutral point of the output terminal of the C-phase inverter / rectifier unit is connected to a two-position switch S35. One path of the two-position switch S35 is connected to R c L c Filter connection, R c L c The filter output is connected to the common point of the smart high-speed grid through fuse FU5 and connected to the C phase 0 DC circuit (i 5C The other side of the double-position switch S35 is connected to the negative electrode of the output terminal of the B-phase inverter / rectifier unit, forming a series connection of the C-phase circuit and the B-phase circuit.

[0105] When controlling the double position switch S33 and R a L a Filter connection, while the switch S30 is closed; control the double position switch S34 and R b L b Filter connection, while the switch S31 is closed; control the double position switch S35 and R c L c The filter is connected and the switch S32 is closed at the same time; the A-phase circuit, the B-phase circuit, and the C-phase circuit are all independent low-voltage circuits, which can achieve low-voltage fast charging.

[0106] When the dual-position switch S33 is connected to the negative output terminal of the C-phase inverter / rectifier unit, forming a series connection between the A-phase circuit and the C-phase circuit, the switch S30 is disconnected, the A-phase high-voltage output circuit is connected, and the switch S32 is disconnected.

[0107] When the dual-position switch S34 is connected to the negative output terminal of the A-phase inverter / rectifier unit, forming a series connection between the B-phase circuit and the A-phase circuit, the switch S31 is disconnected and the B-phase high-voltage output circuit is connected; at this time, the switch S30 is disconnected;

[0108] When the dual-position switch S35 is controlled to be connected to the negative electrode of the output terminal of the B-phase inverter / rectifier unit, forming a series connection of the C-phase circuit and the B-phase circuit, the switch S32 is disconnected and the C-phase high-voltage output circuit is connected; at this time, the switch S31 is disconnected.

[0109] like Figure 5d As shown, SiC MOSFET type transistor (IGBT\ICBT) S' A2 , S′ A4 、S A1 、S A3Three sets of series circuits of resistors and switches are connected in parallel between the control electrode (G electrode) and the neutral line, and the voltage between the control electrode (G electrode) and the neutral line is 10V; the resistor terminal is connected to the drive module, which includes the transistor driver, DSP chip and host computer; the driver and DSP chip are connected to the control electrode and the intelligent fault management system, and the driver and DSP chip are connected to the host computer; the switch is connected to the IO port of the control chip MCU (DSP chip); it is normally turned on by the control chip MCU (DSP chip), and is turned off by the MCU (DSP chip) in equal amounts of time-sharing, and the MCU (DSP chip) is used for intelligent disconnection according to different temperatures, voltages, currents and environments.

[0110] like Figure 5e The transformerless high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion system has a hierarchical shutdown structure for the light storage charging and discharging circuit; SiC MOSFET type transistor (IGBT\ICBT) S' A2 , S′ A4 、S A1 、S A3 Six groups of series circuits (resistors and switches) are connected in parallel between the control electrode (G electrode) and the neutral line, and the voltage between the control electrode (G electrode) and the neutral line is 10V; the resistor terminal is connected to the drive module, and the drive module includes the transistor driver, DSP chip and host computer; the driver and DSP chip are connected to the control electrode and the intelligent fault management system, and the driver and DSP chip are connected to the host computer; the switch is connected to the IO port of the control chip MCU (DSP chip); it is normally turned on by the control chip MCU (DSP chip), and is turned off by the MCU (DSP chip) in equal amounts of time-sharing, and the MCU (DSP chip) is used for intelligent disconnection according to different temperatures, voltages, currents and environments.

[0111] like Figure 19 The structure of the intelligent control and management system for the photovoltaic storage charging and discharging circuit of the transformer-free high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion system is shown, and the transistor (IGBT\ICBT) S′ A2 , S′ A4 、S A1 、S A3The collector (C) and emitter (E) electrodes are connected to the driver module. Faults output by the driver module, such as overtemperature, overcurrent, overvoltage, undervoltage, and short circuit, are input into the intelligent fault management system (controlled by a DSP chip and program). The rising (falling) edge of the PWM signal generated by space vector modulation (SVM) is transmitted to the rising (falling) edge of the secondary gate driver of the transistors (IGBTs / ICBTs). The signals driving the turn-on (turn-off) of the eight transistors (IGBTs / ICBTs) are input into the intelligent control management system. The intelligent control management system transmits fault information, operation request procedures, turn-on, turn-off, and graded turn-off signals to the driver module. The driver module and control chip MCU (DSP chip) implement intelligent disconnection. Any handling of transistors, IGBT modules, or drivers should comply with the general specifications for electrostatic sensitive device protection required by international standards IEC 60747-1, Chapter IX, or IEC 61340-5-2.

[0112] The eight transistors (IGBTs / ICBTs) use an internal NTC temperature detection module to measure the temperature. This is then fed into a positive resistor (R18). This resistor is then connected in series with a thermistor, which is then connected in series with resistor R19. One output from resistor R19 is connected in series with a pull-down resistor (R20) to ground, while the other output is fed into a current-to-frequency conversion module. The resistance of the positive resistors R18 and R19 is higher than that of the pull-down resistor (R20). When the thermistor detects the highest temperature, it generates a corresponding current. This current-to-voltage conversion is then fed into a digital verification module (analog-to-digital conversion). This frequency signal is then output to the intelligent control management system, which then outputs the test frequency. Based on the test frequency, the corresponding eight transistors (IGBTs / ICBTs) are intelligently controlled to adjust the cooling and heating control times. This prevents overheating of the eight transistors (IGBTs / ICBTs). Frequency-adjusted temperature control time can be precisely controlled to within ±0.5°C, resulting in a thermal lifespan of up to 100,000 hours.

[0113] The advantages of using hierarchical shutdown intelligent control are significant. In applications with high stray inductance, such as multi-level, large commutation circuits, the IGBT faces the risk of excessively high turn-off spikes each time it shuts down. Due to the thermal capacity limitations of the TVS, peak absorption power can reach 600W, and the clamping voltage is 18V. Active clamping technology, which reliably protects the IGBT gate driver, is not suitable for these applications. This is where hierarchical shutdown technology can be very effective. By using different turn-off resistors during the shutdown process, the entire shutdown process is optimized, suppressing the turn-off spikes. This addresses the risk that existing software control technologies, when used with large-scale photovoltaic and wind power integration, can only shut down within 4-8µs, or fail to shut down after 10µs.

[0114] like Figure 6As shown, in some embodiments, five groups of electronic multi-position conversion switches are correspondingly connected to four series capacitors C1\C2\C3\C4, and the positive electrodes of five inductive non-isolated buck-boost bidirectional chargers with the same structure are all connected to the positive electrodes of the corresponding five groups of electronic multi-position conversion switches, and the negative electrodes are connected to the negative electrodes of the corresponding five groups of electronic multi-position conversion switches.

[0115] Each inductive non-isolated buck-boost bidirectional charger / discharger includes corresponding battery energy storage groups Cell1, Cell2, Cell3, Cell4, and Cell5. Taking battery energy storage group Cell1 as an example:

[0116] Capacitor C a 3 One end is connected to the control line P1, capacitor C a 3 The other end is connected to the G pole of MOSFET tube Q1, and the D pole lead of MOSFET tube Q1 is connected to the resistor R a 1 one end is connected to the resistor R a The other end of 1 is connected to the capacitor C a 3 and the G pole of MOSFET tube Q1; the S pole lead of MOSFET tube Q1 is connected to the D pole of MOSFET tube Q2, and the G pole lead of MOSFET tube Q2 is connected to the capacitor C a 4 one end is connected to capacitor C a 4 The other end is connected to the control line P2, and the S-pole lead of the MOSFET tube Q2 is connected to the resistor R A 2 one end connected to the resistor R A 2The other end is connected to capacitor C a 4 and the G-pole lead of MOSFET tube Q2; a capacitor C is connected in series between the D-pole lead of MOSFET tube Q1 and the S-pole lead of MOSFET tube Q2. a 2 and capacitor C a 1. The D-pole lead of MOSFET tube Q1 is used as the positive pole of the energy exchange driving power supply and is connected to the positive pole of the electronic multi-position switch;

[0117] Resistor R a 9 and inductor L a 1 One end of the parallel node is connected between MOSFET tube Q1 and MOSFET tube Q1, and the resistor R a 9 and inductor L a The other end of the parallel connection point is connected to the capacitor C a 2 and capacitor C a 1 series node; capacitor C a 2 and capacitor C a The lead wire of the series node of 1 is used as the negative electrode of the energy exchange driving power supply and is connected to the negative electrode of the electronic multi-position switch;

[0118] Capacitor C a 2 and capacitor C aThe lead wire of the series node of 1 serves as the positive terminal of the battery energy storage group Cell1, and the S-pole lead wire of the MOSFET tube Q2 serves as the negative terminal of the battery energy storage group Cell1.

[0119] Figure 6 The battery energy storage groups Cell1, Cell2, Cell3, Cell4, Cell5 and Figure 5a The battery energy storage groups Cell1 to Cell5 are different. Figure 6 Share a set of four series capacitors C1\C2\C3\C4 with Figure 5, Figure 6 The circuit does not require R a L a Filter, R b L b Filter, R c L c Filtering, the rest of the circuit is the same as Figure 5.

[0120] The electronic multi-position switch is connected to a 5-level inductor non-isolated buck-boost bidirectional charger and discharger. The working principle is as follows: when the photovoltaic cell array (smart grid) and the 640KW battery energy storage unit exchange bidirectional electric energy; the 5-level DC is connected to the positive and negative poles of the driving power supply of the MOSFET tube Q1 through the electronic multi-position switch. The control line P1 drives the MOSFET tube Q1 at a frequency of several hundred Hz, inputting the higher voltage photovoltaic cell array (smart grid) into the 5-level DC end current, triggering energy transfer. The 5-level DC end current flows into the inductor L at high or low frequency. a 1. Inductor L a 1 is charged to saturation; when the control line P1 signal is reset, the MOSFET tube Q1 is turned off and the inductor L a 1. The high level of stored energy will forward bias the MOSFET tube Q2, and the MOSFET tube Q2 will shunt the energy to the battery energy storage group Cell1 with a lower voltage. The above process is repeated until the battery energy storage group Cell1 is saturated with energy. Similarly, when the bottom battery energy storage group Cell1 needs to transfer energy to DC loads, main loads, general loads, charging piles, building users, industrial user loads, smart grids, etc., the control line P2 drives the MOSFET tube Q2 at a high or low frequency, and the current flows through the MOSFET tube Q2 to the inductor L. a 1. Inductor L a When 1 is charged to saturation, the control line P2 signal is reset, the MOSFET tube Q2 is turned off, and the inductor L aHigh-level stored energy forward-biases MOSFET Q1, which then diverts the energy to a lower-voltage drive power supply. This energy then flows through an electronic multi-position switch and is discharged into a five-level DC multi-quadrant converter. This energy is then delivered to the smart grid, primary loads, general loads, charging stations, building users, industrial user loads, and low-voltage distributed solar-storage-charge-discharge flexible energy (dual-carbon) evaluation and management. This process is repeated until a large-scale distributed flexible solar-storage-charge-discharge system based on IoT-sensing dual-carbon evaluation is achieved, ensuring uninterrupted power, no interruptions, no power outages, no impact, and enabling safe, smooth, and seamless switching between different systems.

[0121] The electronic multi-position switch in this embodiment of the present invention connects a five-stage inductive non-isolated buck-boost bidirectional charger / discharger. This overcomes the power limitations of existing transformer-based balancing circuit technology, particularly the lack of high-voltage, high-current systems for existing solar-powered storage and charging systems. It offers advantages such as high balancing current, long balancing time, low heat dissipation, and a 980% increase in charging efficiency. Five identically structured inductive non-isolated buck-boost bidirectional chargers can be freely combined, flexibly adapting to voltages from 480-1500V (with a withstand voltage of 1800V-2000V) and automatically adjusting power, enabling flexible control.

[0122] The grid-connected inverter side of the distributed photovoltaic storage charging and discharging station adopts inner loop current and outer loop voltage ( Figure 8aAs shown), phase-locked dual-loop dual-vector control (such as but not limited to the DDSFR-PLL of the prior art), consists of 4 parallel paths, each boost or buck-boost type with a rated power of 250KW / 320KW, 1000V, boost 1500V, adjustable voltage 480V-1500V, and a rated power of 1 MW level 5 DC input, which is inverted into an independent single-phase and paralleled into a three-phase rated 380V AC, and is connected to the smart grid (35KVD) through the first AC bus and the distribution step-up transformer. Each 250KW / 640KW is composed of 18 photovoltaic cell modules in series in a photovoltaic array, 52 (134) in parallel (the maximum power of the battery is 265W) (a rated 1 MW is composed of 4 photovoltaic arrays of 250KW each, composed of 18 photovoltaic 265W batteries, 1 in series, 52 in parallel to form a square array (abbreviated as 5 18-series 52-parallel 1.25 MW); compatible with a rated 3.2 MW (obtainable after boosting), composed of 5 photovoltaic arrays of 640KW each, composed of 18 photovoltaic 265W batteries, 1 in series, 134 in parallel to form a square array (abbreviated as 5 18-series 134 parallel 3.2 MW); step-down The capacitor value at the input of the (boost) or boost circuit is 10000μF, and the inductor value is 0.01H; the capacitor at the input of the converter is 50000μF, the inductor value at the output is 0.6Mh, the EMI filter resistor value is 5Ω, the inductor value is 0.3H, and the capacitor value is 200μF. The low-voltage side of the buck (boost) or boost circuit output is 512V, and the inverter grid connection point is 380V. Each boost or buck-boost control uses the maximum power point MPPT controller to calculate the adjustable voltage (maximum and minimum voltage limit voltage). The reference voltage at the input of the boost or buck-boost circuit is used to adjust the output voltage V of the photovoltaic array. pv , achieving maximum power point tracking. The middle and outer loops control DC voltage and reactive power, respectively, while the inner loop employs dual vector control for current and frequency. The inverter utilizes the search value evaluation (SVM) vector control method.

[0123] like Figure 3 As shown, the low-voltage distributed photovoltaic storage charging and discharging flexible electric energy (dual carbon) evaluation and control system includes: 5 groups of 640KW battery energy storage units, 2 groups of bidirectional multi-phase converter units, optical switches, client timing systems, AC and DC cloud interconnection of mains power, photovoltaic storage charging and discharging control management station, PCS system and EMS battery monitoring and control system.

[0124] Each battery energy storage unit is connected to a corresponding EMS integrated management and monitoring system and an on-site converter controller. One bidirectional multi-phase converter unit is connected to a corresponding PCT (Power Transmitter) discharge module to the grid generator, and a grid-to-battery cabinet and energy storage battery unit charging module. Another bidirectional multi-phase converter unit is connected to a corresponding megawatt-class energy storage unit-to-grid PCT discharge module and a bidirectional high-precision electric energy dual-carbon metering and evaluation module. This system implements bidirectional storage, charging, and discharge management, as well as bidirectional high-precision electric energy dual-carbon metering and evaluation. It also adds AC / DC interconnection and AC / DC cloud interconnection scheduling, as well as balanced battery pack and battery family temperature thermal management. The grid PCT discharge module specifically refers to a thyristor module grid protection module (existing technology).

[0125] The EMS integrated management and monitoring system and the PCT to grid generator discharge module are connected to the time synchronization network (IRIG-B) and Ethernet (MOdbUS); the converter local controller, the grid to battery cabinet and energy storage battery unit charging module, the megawatt energy storage unit to grid PCT discharge module and the bidirectional high-precision electric energy and carbon measurement evaluation module are all connected to the time synchronization network (IRIG-B) and Ethernet (104);

[0126] The timing network (IRIG-B), Ethernet (MOdbUS), and Ethernet (104) are all connected to the optical switch, the client timing system, and the AC / DC cloud interconnection of the mains; the optical switch is connected to the optical storage charging and discharging control management station through the ModbUS and 104 optical fiber interfaces.

[0127] The PCS system and EMS battery monitoring system are composed of multiple battery management units, high-voltage boxes, battery family control management units ESBCM, and BMS system management host ESMU.

[0128] Two batteries form a group, and the battery management unit (13) is connected to the battery family control management unit ESBCM through the CAM bus; the current detection module, total voltage detection module, and DC circuit breaker are all connected to the battery family control management unit ESBCM. Different battery family control management units ESBCM are connected through CAN / RS485 and communicate with the BMS system management host ESMU and EMS battery monitoring and control system; the current detection module, total voltage detection module, DC circuit breaker, fuse, and circuit breaker form a high-voltage box.

[0129] The battery management unit (BMM) is used to collect the voltage and temperature of each photovoltaic cell module, execute the balancing strategy, and exchange data information with the battery control and management unit (ESBCM) via CAN communication.

[0130] The battery family control and management unit ESBCM is used to collect the voltage, current and temperature of the photovoltaic battery group;

[0131] Control of the contactor for battery pack protection, battery management unit ESBMM collects photovoltaic cell voltage and temperature, real-time detection of thermal management and passive balancing capabilities, realizes data system information interaction with BMS system management host ESMU, and realizes data information interaction with PCS system and EMS battery monitoring system.

[0132] The BMS system management host ESMU collects all information of the battery array (system) in real time, displays relevant information of the battery array (system) in real time, stores operation information, and has real-time warning function.

[0133] Existing solar-storage charging and discharging systems suffer from uneven thermal management, low capacity, a single battery charging method, a power outage rate greater than 2%, and a system overflow rate of 25%-30%. The solar-storage charging and discharging system of the present invention has an overflow rate of less than 5%, reduces the power outage rate to 2% or less, and reduces the average energy cost by 80%.

[0134] The EMS battery monitoring system includes upper and lower monitoring systems; the upper monitoring system includes a data server, a telecontrol server, an operation server, and a network communication unit.

[0135] The telecontrol server is connected to the upper-level joint monitoring system. It first transmits the operating status of the energy storage power station (a combination of five 640kW battery energy storage units), UPS inverter, and multi-quadrant converter to the upper-level joint monitoring system in real time. The transmitted information includes the following:

[0136] (1) The remaining energy (SOC) of the energy storage station and each battery submodule, the overall output status of the energy storage station (overall power ∑P, overall discharge capacity ∑Q), the output status of each energy storage module (each battery submodule) (power P within 1 second) n , power P in one cycle nn , discharge capacity within 1 second Q n 、Discharge capacity in one cycle Q nn ), the corresponding power regulation depth (power regulation depth ΔP, discharge capacity regulation depth ΔQ, power regulation depth within 1 second ΔP n , Discharge capacity adjustment depth ΔQ within 1 second n ), the power regulation depth of the energy storage power station (power regulation depth ΔP', discharge capacity regulation depth ΔQ'), ΔE represents the available depth of energy storage capacity; ΔE n Indicates the available depth of the nth battery pack.

[0137] Health status (HOC) parameters for each energy storage battery submodule and photovoltaic battery pack include: battery (PV cell) temperature, number of repairs and maintenance, cycle count, battery pack consistency, conversion efficiency, etc. Health status and temperature of diodes and power switches in multi-quadrant converters, distribution boost transformers, buck-boost circuits, and inverters; status of fans, water chillers, and circuit breakers; and bidirectional smart meters measure electricity, electricity costs, and equivalent conversion of carbon dioxide and its transaction volume and price. The system receives real-time dispatch commands and operation plans from higher-level joint monitoring systems.

[0138] (2) According to the joint monitoring scheduling plan, combined with the battery energy status, the output plan within the next 3 days, 24 hours, 15 minutes, and 1 minute is arranged in real time.

[0139] (3) Data services provide real-time storage of various monitoring data, historical data archiving, and background analysis.

[0140] (4) Run the server, decompose the output to each type of battery in real time according to the instruction plan of the remote control server, and arrange the output plan of the battery energy storage unit in real time (according to the diodes and power switches (transistors) in the photovoltaic cells and inverters, the buck-boost circuit, and the corresponding adjustment of the inverter power); arrange the output plan of the energy storage system within 30 seconds, and calculate the output ∑P and ∑Q required by the energy storage system in the next second according to the real-time photovoltaic output value of the access point; arrange the output ∑P and ∑Q of each type of battery energy storage system in the next second according to the ∑P and ∑Q requirements; on the time scale, the flow battery is mainly responsible for the P of each cycle nn , Q nn Output compensation instantaneous fluctuations; lithium-ion batteries compensate for P every second nn , Q nn Second-level fluctuations, sodium-sulfur batteries P every second nn , Q nn Compensate for minute-level fluctuations.

[0141] The lower-level monitoring system is connected to the upper-level monitoring system via an Ethernet industrial bus and to the underlying built-in monitoring system of each energy storage unit via a fieldbus. It monitors the energy storage status of flow batteries, lithium-ion batteries, and sodium-sulfur batteries. Each lower-level monitoring system separates the monitoring and control data lines.

[0142] The basic information unit for lithium-ion batteries is 250KW / 320KW, the basic information unit for sodium-sulfur batteries is 100KW, and the basic information unit for liquid flow batteries is 250KW; the basic information unit for lithium-ion and liquid flow converters is 500KW / 640KW, the basic information unit for sodium-sulfur batteries is 1MW converter, and the basic information unit for transformers is 2.5MV·A / 3.2MV·A.

[0143] like Figure 4As shown, a combination of five 640kW battery energy storage units with a capacity of 3.2MV·A is connected to a 380V 35kVA smart grid. The relationship between the five 640kW battery energy storage units and the megawatt-class battery energy storage units is that the 1.25MW circuit is boosted to 1.6MW; the 1.6MW multidirectional converter and the 1.6MW UPS inverter are combined to form a power-balanced combination of five 640kW battery energy storage units (3.2MW).

[0144] The system consists of an EMS battery monitoring and management control system, a local converter controller, an optical switch, a photovoltaic storage charge and discharge control and management system, AC / DC interconnection with the mains, a client timing system, a PCS system, five 640kW battery energy storage units, a five-level DC bus, and a smart grid. These units are connected via electronic multi-position switches to a five-level inductive non-isolated buck-boost bidirectional charger and discharger, a photovoltaic storage charge and discharge intelligent management controller, a battery pack DC and smart grid charge and discharge converter, a low-voltage distributed photovoltaic storage charge and discharge flexible electric energy (dual carbon) evaluation and management system, and a DC network control system consisting of a PCS, battery cabinet, rectifier, and high-precision bidirectional AC / DC meter. Each 640kW battery energy storage unit is charged by a 640kW bidirectional multi-phase converter, and is charged by the smart grid when the converter is unable to supply power. The PCS, battery cabinet, and bidirectional charge and discharge megawatt-class battery energy storage group supply and discharge electricity to the smart grid, charging piles, major loads, general loads, building user loads, industrial electricity, and equipment.

[0145] The megawatt-class battery energy storage group consists of 13 BMSs and 13 lithium-ion battery packs. 32 battery packs are connected in series to form a group of battery sub-units. Each battery sub-unit is equipped with monitoring. The four battery sub-units are connected through the DC bus of the battery energy storage unit, and are connected to the 640KW bidirectional converter (multi-image converter) through CAN bus communication and energy storage monitoring system. There are multiple 640KW bidirectional converters to form a megawatt-class battery energy storage unit.

[0146] Figure 4 The BMS in Figure 3 The BMS system management host ESMU, Figure 4 The energy storage monitoring system is Figure 3 EMS battery monitoring and control system in Figure 4 The 640KW bidirectional converter (multi-converter) is Figure 3 Bidirectional multi-phase converter unit, Figure 3 To monitor the architecture of smart grid access, Figure 4 The role played in this application is to provide online parameters for bidirectional high-precision electric energy and carbon measurement and evaluation; and realize bidirectional electric energy exchange.

[0147] like Figure 7 、 Figure 9As shown in FIG, the topological circuit structure of the photovoltaic storage charging and discharging intelligent management controller includes a bidirectional TVS transient voltage suppression diode connected between the positive and negative terminals of the photovoltaic module;

[0148] The output end of the diode VD is connected to the D pole of the field effect enhancement type N-MOS tube VT1, the input end of the diode VD and the S pole of VT1 are connected to the positive terminal and negative terminal of the photovoltaic module respectively; the G pole of VT1 is connected to the output end of the operational amplifier of the PWM power drive module.

[0149] The positive pole of the operational amplifier power supply of the PWM power drive module is connected to the G pole of the field effect enhancement type N-MOS tube VT2, the D pole of VT2 is connected to the negative pole of the photovoltaic module, and the S pole of VT2 is connected to the S pole of the field effect enhancement type N-MOS tube VT2.

[0150] The operational amplifier output of the PWM power drive module is connected to the MCU microprocessor, and the MCU microprocessor output is connected to the negative end of the photovoltaic module, the input end of the current sensor S1, the input end of the temperature sensor T1, and the negative end of the energy storage battery pack in sequence; the current sensor S1 is connected to the negative output line of the photovoltaic module.

[0151] The positive electrode of the energy storage battery pack is connected to the positive electrode of the voltage sensor detection circuit. The undervoltage detection control IC2 output 2G and the overvoltage detection control IC1 output 1G are both connected to the MCU microprocessor;

[0152] The output protection and power driving module (known in the art) is connected to the G pole of the field effect enhancement type N-MOS tube VT3, and the D pole of VT3 is connected to the output load.

[0153] The inverting input terminal of the operational amplifier of the PWM power driving module is connected to the output terminal of the voltage stabilizing diode VD3, the output terminal of the voltage stabilizing diode VD3 is connected to a first upper resistor, the first upper resistor is connected to the same-direction output terminal of the PWM power driving operational amplifier, the other end of the first upper resistor is connected to the positive terminal of the photovoltaic module, and the input terminal of the voltage stabilizing diode VD3 is connected to the negative terminal of the photovoltaic module;

[0154] The second upper resistor and the second lower resistor are connected in series between the positive terminal and the negative terminal of the photovoltaic module, the negative terminal of the energy storage battery is connected to the positive terminal of the photovoltaic module, and the positive terminal of the energy storage battery is connected to the negative terminal of the photovoltaic module; the positive terminal of the energy storage battery is connected to the negative terminal of the photovoltaic module through the fuse FU.

[0155] The voltage sensor detection circuit consists of an overvoltage detection control circuit and an undervoltage detection control circuit. The overvoltage detection control circuit includes an IC1 amplifier. One of the inverting input terminals of the IC1 amplifier is connected to one end of a resistor R3, and the other is connected to the positive electrode of the power supply. The other end of the resistor R3 is connected to the negative electrode of the power supply. Both ends of the resistor R3 are connected to a capacitor C3.

[0156] The positive input terminal of the IC1 amplifier operator is connected to the sliding terminal of the adjustable resistor W1, one end of the adjustable resistor W1 is connected to the negative electrode of the power supply, the other end of the adjustable resistor W1 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the positive electrode of the power supply; the two ends of the resistor R4 are connected to the diode VD4, and the input terminal of the diode VD4 is connected to the negative electrode of the power supply; the relationship between the adjustable resistor W1 and the resistor R4 is a positive proportional relationship.

[0157] One output end of the IC1 amplifying operator is connected to one end of the variable resistor R1, and the other end of the variable resistor R1 is connected to the inverting input end of the IC1 amplifying operator; the other output end of the IC1 amplifying operator is connected in series with resistors R6 and R7 in sequence to the negative pole of the power supply, and both ends of the resistor R7 are connected to a capacitor C4. The lead wire between the capacitor C4 and the resistor R6 serves as the output 1G of the overvoltage detection.

[0158] The undervoltage detection control circuit includes an IC2 amplifier operation unit. One of the positive input terminals of the IC2 amplifier operation unit is connected to one end of a resistor R8, and the other is connected to the positive electrode of the power supply. The other end of the resistor R8 is connected to the negative electrode of the power supply. Both ends of the resistor R8 are connected to a capacitor C5.

[0159] The inverting input of IC2's amplifying operator is connected to the sliding end of adjustable resistor W2. One end of adjustable resistor W2 is connected to the negative power supply, and the other end of adjustable resistor W2 is connected to one end of resistor R10. The other end of resistor R10 is connected to the positive power supply. Resistor R9 is connected to diode VD5 at both ends, with its input end connected to the negative power supply. Adjustable resistor W2 and resistor R9 are inversely proportional. One output of IC2's amplifying operator is connected to one end of variable resistor R12, the other end of which is connected to the positive input of IC2's amplifying operator. Resistors R12 and R11 are connected in series between the other output of IC2 and the negative power supply, respectively. Resistor R11 is connected to capacitor C6 at both ends, and the lead wire between capacitor C6 and resistor R12 serves as the undervoltage detection output 2G.

[0160] Among them, the reverse input terminal of IC1 is not connected to the resistor R5, the forward input terminal of IC2 is not connected to the resistor R10, and the relationship between the power supply and the energy storage battery is a synchronous relationship.

[0161] The circuit of the solar storage charging and discharging intelligent management controller adopts IC type PWM or SVPWM, CPU or MCU ( Figure 7The MCU microprocessor in the controller collects the operating parameters of photovoltaic power generation in real time at high speed. In the controller, the program cuts off and connects single-channel and multi-channel photovoltaic modules and battery modules, and 5-level DC to realize intelligent control of light storage and charging. The controller can also control and transmit data through the RS232 / 485 interface of the single-chip computer, microprocessor, and Internet of Things chip through computers, power network clouds, and conduct long-distance communication and control.

[0162] In addition to protection against overcharge, overdischarge, overload, and reverse polarity, this intelligent control system also utilizes highly accurate charge and discharge rate control for the energy storage battery, high-precision temperature compensation, and compensation for grid outages, generators, charging stations, and other power shortages. Specifically, it features an LCD dot matrix module that allows for arbitrary programming of charge and discharge parameters, temperature compensation coefficient voltage compensation, battery current limit, grid voltage compensation limit, photovoltaic DC bus voltage balancing adjustment, inverter tube voltage adjustment, and displays of each photovoltaic charging and discharging status and load on / off status. It has the functions of photovoltaic, smart grid, battery, electricity purchase and sale by different users, and dual carbon equivalent accumulation; it can display in real time the energy storage voltage, load current, charging (discharging) current, photovoltaic (smart grid supplement) current, energy storage battery, photovoltaic battery, power tube temperature, cumulative photovoltaic power generation ampere-hours and wattage, cumulative load (charging pile) power consumption and other parameters; it has 1-12 photovoltaic module input control circuits, the control circuit is completely isolated from the main circuit, and has extremely strong anti-interference ability; it has historical data statistical display function, such as the number of overcharges, over-discharges, overloads, short circuits, etc.

[0163] Users can set the load on / off status for battery overcharge and overdischarge protection. The system provides alarms and protections for battery overcharge, overdischarge, output overload, short circuit, surge, reverse connection or short circuit of photovoltaic cells, reverse connection of battery cells, and reverse charge / discharge at night. Passive dry contacts are provided for generator or backup power supply startup circuits, depending on system requirements. The system also features a real-time clock function that displays and sets the clock. Equipped with RS232 / 485 and wireless interfaces, it facilitates remote or wireless telesignaling and remote control. The PC monitoring software can measure real-time data, display alarm information, modify control parameters, and read 30 days of daily historical data such as the maximum and minimum voltages of the energy storage battery, photovoltaic cell, and power tube, daily cumulative photovoltaic power generation, daily load, and system charge and discharge accumulation. Parameter settings are password-protected and user-changeable. It features protection alarms for overvoltage, undervoltage, overload, and short circuit, and has multiple passive output alarm or control contacts, including alarms for energy storage battery overcharge and overdischarge, startup control of other power generation equipment, load disconnection, control failure, and flooding. It also has lightning protection and temperature compensation. Operating modes include normal charge and discharge modes (stepped current limiting mode) and single-point (PWM operating mode). Single-point charge and discharge is divided into three to four stages: constant current fast charge, constant voltage equalization, and float charge. This precise control effectively protects the energy storage battery from overcharge and fully utilizes solar energy.

[0164] Intelligent control system parameter setting range: system voltage 12V-192V; maximum charging current 5A-300A;

[0165] PV array input 2-12 channels; the maximum self-loss of the controller does not exceed 1% of the rated charging current or 0.4W, and the loss current is 5-20Ma;

[0166] The energy storage battery overcharge protection voltage (HVD) realizes full disconnection or overvoltage shutdown voltage; 12V system setting is 14.1-14.5V; 24V system setting is 28.2-29V; 48V system setting is 56.4-58V;

[0167] The shutdown recovery voltage (HVR) setting for energy storage overcharge protection is 13.1-13.4V for 12V system, 26.2-26.8V for 24V system, and 52.4-52.8V for 48V system.

[0168] The energy storage battery over-discharge protection voltage (LVD) realizes undervoltage disconnection or undervoltage shutdown voltage; the 12V system is set to 10.8-11.4V; the 24V system is set to 21.6-22.8V; the 48V system is set to 43.2-45.6V;

[0169] The shutdown recovery voltage (LVR) setting for energy storage overload protection is 12.1-12.6V for 12V system, 24.2-25.2V for 24V system, and 48.4-50.4V for 48V system.

[0170] Energy storage battery floating charge voltage: 12V system set to 13.7V; 24V system set to 27.4V; 48V system set to 54.8V;

[0171] Energy storage battery temperature compensation -20-40mV / °C; operating temperature -20-50°C; controller lightning protection, surge voltage and surge current resistance (tested to 1.25 times the nominal current (voltage) for 1 hour without damage to the controller). The controller should be 10%-20% larger than the photovoltaic output parameters.

[0172] The working principle of the photovoltaic storage charging and discharging intelligent management controller is as follows: a multi-position switch 1 (not shown in the figure) is connected between the photovoltaic module, the smart grid and the controller to serve as a charging control switch; Figure 6 The multi-position transfer switch (multi-position switch 2) of the electronic industry is used as the discharge control switch. When there is sunlight or the photovoltaic module is powered off for maintenance, the multi-position switch 1 is switched closed, and the photovoltaic module converts the light energy into DC power (the smart grid rectifies AC into DC through the inverter). The photovoltaic storage charge and discharge intelligent management controller controls the 5-level inductive non-isolated buck-boost bidirectional charge and discharge circuit to charge the energy storage battery pack. When the energy storage battery pack is overcharged, the multi-position switch 1 promptly cuts off the charging circuit, causing the photovoltaic module (smart grid) to stop charging the energy storage battery pack. The multi-position switch 1 can also naturally resume charging the energy storage battery pack according to the preset protection mode. The electronic multi-position transfer switch is installed in Figure 2 At S2 in .

[0173] When the multi-position switch 2 is switched closed, the photovoltaic storage charging and discharging intelligent management controller controls the energy storage battery pack to supply power to the load, charging pile, generator, and smart grid. When the energy storage battery pack is over-discharged, the multi-position switch 2 promptly cuts off the discharge circuit, causing the energy storage battery pack to stop supplying power to the load, charging pile, generator, and smart grid. When the energy storage battery pack is charged again and reaches the preset recovery charging point, the multi-position switch 2 can also naturally recover and supply power to the load, charging pile, generator, and smart grid.

[0174] The solar-storage charging and discharging intelligent management controller features voltage, current, PWM, and MPPT control of solar-storage charging and discharging. It also includes real-time online detection of over / undervoltage in the solar-storage battery and, based on the detection results, signals to the overcharge and over-discharge switches to turn on or off. IC1, an operational amplifier with hysteresis control, is an overvoltage detection circuit. IC1's non-inverting input inputs a reference voltage, while its inverting input connects to the energy storage battery pack. When the battery pack voltage exceeds the overcharge voltage, IC1's output G1 goes low, causing switch 1 to connect the parallel circuit or disconnect the series circuit, providing overvoltage protection. When the battery pack voltage drops below the overcharge voltage, IC1's inverting input input voltage drops below the non-inverting input voltage, causing IC1's output G1 to change from low to high, and the battery pack returns to normal charging. The threshold voltage for overcharge protection and recovery is adjusted by W1 and R1, where W1 represents the connection line for the adjustable resistor and R1 represents the adjustable resistor.

[0175] The working principle of the undervoltage detection control circuit is the same as that of the overvoltage detection control circuit; the intelligent management controller for light storage charging and discharging is based on voltage and current switch control, and at the same time uses MPPT to track the PV output power at the maximum point. If the pulse width and duty cycle of PWM (or SVM) are not adjusted, the charging current is changed, and real-time sampling is performed again to make the photovoltaic array operate at the maximum power point. At the same time, the charging current becomes a pulse current modulated by PWM, and the MPPT obtains a larger high voltage photovoltaic voltage, and through voltage reduction, it reaches the appropriate charging voltage of the energy storage battery group, increases the charging current, keeps the power unchanged and charges at a high speed, and is controlled by the integrated control platform of light (wind) multi-control links ( Figure 1The BEMS, distributed photovoltaic storage charging and discharging stations, and batteries in the battery cabinets connected to the PCS are designed to regulate the DC voltage in different operating modes while keeping the DC bus voltage within the allowable range. Charging is carried out in three stages. In the first stage, the batteries are charged at a constant current at the nominal battery charging current. When the battery voltage reaches the discharge voltage, the second stage begins, completing the charge using a constant voltage charging method. The third stage corresponds to a float charge when the battery is fully charged. Battery discharge control is also important, ensuring smooth DC voltage regulation by controlling power discharge according to the required load. Furthermore, the control system is designed to limit battery discharge current and avoid overdischarge when the battery SOC falls below the allowable value, or overload when the required power exceeds the battery's maximum power. In such cases, a load shedding strategy should be implemented. When the PWM pulses are fully charged according to the three stages, as the terminal voltage gradually increases, the PWM pulse frequency and timing change, increasing the switch on-time, shortening the interval, and gradually approaching zero charging current. As the energy storage battery pack decreases from the full charge point, the charging current gradually increases to near the overcharge point, where it approaches zero. PWM shutdown increases the charging efficiency of the solar storage system, reduces the polarization of the energy storage battery pack, and extends the life of the energy storage battery pack, expanding the selection range of photovoltaic modules and reducing the cost of photovoltaic power generation.

[0176] The photovoltaic storage charging and discharging intelligent management controller converts the DC power of the energy storage battery group into AC power through the photovoltaic inverter to supply power to the load and the smart grid at night, on rainy days, or when the smart grid is out of power. The ultra-large capacity DC power can directly supply power to the DC load. At the same time, when encountering continuous cloudy and rainy days, it can switch to the smart grid to reversely supply power to the load and energy storage battery when its own power generation and storage are insufficient. When the energy storage battery is charged to a certain amount, the smart grid is cut off from supplying power to the load and the energy storage battery is switched to supply power to the main load and general load through the UPS inverter and multi-phase converter, as well as the normal operation of photovoltaic power generation, until the photovoltaic components meet the requirements. Until normal power supply can be achieved, switch to the normal mode of photovoltaic storage charging and discharging to achieve uninterrupted power supply; at the same time, the "self-generation and self-use", "daytime generation and nighttime use", and "surplus power access to the grid" characteristics of photovoltaic storage charging and discharging are used to implement peak-valley regulation and differentiated power supply in different time periods for the smart grid, thereby increasing the power supply proportion and status of photovoltaic storage charging and discharging in the grid-connected smart grid, eliminating the impact on the smart grid during grid connection startup, stabilizing the grid voltage, offsetting the power consumption during peak hours, increasing users' self-generation and self-use or sales of electricity, and being able to operate independently in the event of a grid failure, thus solving the normal and flexible power supply in the coverage area and greatly reducing the cost of power generation.

[0177] Smart grid also includes wind, solar and storage integrated system, bidirectional smart electricity meter and dual carbon meter for measuring each network. Wind, solar and storage integrated system (i.e. master-slave integrated flexible wind, solar, storage and charging integrated platform), such as Figure 8b As shown, the master-slave integrated flexible wind-solar storage-charging-discharging integrated platform includes a hybrid energy storage platform.

[0178] Total output power P of power bus (all AC bus and DC bus) w , access the first U, I measurement module through current and voltage sensors, and the measured values ​​of the current and voltage sensors are used to calculate the reference power through power software and input into the energy storage hybrid power distribution unit. The energy storage hybrid power distribution unit sends the reference power output to the hybrid algorithm unit; the hybrid algorithm unit includes an SOC adaptive algorithm module, an SOC fuzzy control algorithm module, a VGA control algorithm module and a voltage / current estimation method module; the energy storage hybrid power distribution unit is connected to the SOC adaptive algorithm module, the SOC fuzzy control algorithm module, the VGA control algorithm module and the voltage / current estimation method module through a multi-position electronic switching switch; the hybrid algorithm module combines the wind, solar and storage planned output to output the first distributed power.

[0179] Each algorithm module in the hybrid algorithm unit is connected to a type I low-pass filter (LPF) through a multi-position electronic automatic switching switch. The second distribution power output by the type I low-pass filter (LPF) and the first distribution power output by the hybrid algorithm unit are both input into the first comparator. The first comparator is used to correct the difference between the two distribution powers to obtain the classified power and send it to the converter power voltage control module. The converter power voltage control module outputs the actual energy storage power to the hybrid energy storage platform through the DC / AC conversion module.

[0180] The classified power output by the first comparator and the first allocated power output by the hybrid algorithm unit are both input to the second comparator, and the second comparator outputs the planned classified power to the hybrid battery pack unit control platform to perform planned control on the megawatt-level battery pack module; the classified power output by the first comparator is fed back to the hybrid algorithm unit to improve the algorithm accuracy.

[0181] Taking into account the SOC conversion control module, the battery remaining capacity is sent to the hybrid algorithm module and the electric energy over-limit protection unit respectively; the battery current and voltage test module sends the tested voltage and current values ​​to the hybrid algorithm module and the electric energy over-limit protection unit respectively; the electric energy over-limit protection unit sends the over-limit parameters to the hybrid battery pack unit control platform; the hybrid battery pack unit control platform includes megawatt-class lithium iron phosphate battery packs, supercapacitors and lead-acid battery packs, lithium battery packs, lead-acid battery packs, sodium-sulfur battery packs, MH-Ni battery packs, lithium aggregate battery packs, all-vanadium liquid battery packs, other material battery packs, and DC voltage + current + PWM plan control modules; the hybrid battery pack unit control platform controls the remaining amount of corresponding battery energy storage through DC voltage + current + PWM plan.

[0182] The hybrid energy storage platform inputs the power of the complementary battery packs into the master-slave controller, which includes an active / reactive droop (PQ) control module and a voltage / frequency droop (V / f) control module. The master controller responds to power shortages and charging and storage, while the slave controller responds to load power supply with no power shortages. Power shortages in the large system are alleviated through grid connection.

[0183] Active and reactive power droop PQ control module, used for master-slave integrated flexible wind-solar storage-charge-discharge integrated platform grid-connected smart grid-municipal grid;

[0184] The voltage-frequency droop V / f control module is used for the master-slave integrated flexible wind-solar storage-charging-discharging integrated platform and grid-connected smart grid - DC microgrid and AC microgrid.

[0185] The input end of the master-slave controller is connected to the grid synchronization signal measurement module through the electronic switching switch S22. The electronic switching switch is used to automatically switch between the grid and the microgrid; the grid synchronization signal measurement module is connected to the DC microgrid and the AC microgrid through the switches at the PCC (common connection point) of the first AC mains grid and the second AC mains grid respectively. The DC microgrid and the AC microgrid are connected through a multi-position transfer switch and an AC / DC conversion module.

[0186] The DC bus is connected to the DC microgrid, the AC microgrid is connected to the AC bus, and the current and voltage sensors connected to the output terminals of the master-slave controller are connected to the DC microgrid and the AC microgrid respectively ( Figure 8b The output ends of the master and slave controllers are connected to the hybrid battery unit and the UI measurement module through the DC / AC conversion module to provide real-time parameters for power calculation.

[0187] The AC bus is connected to the converter, the DC bus is connected to the 5-level DC conversion module (diode-clamped multi-level two-stage topology circuit), and the 5-level DC conversion module is connected to the wind and solar storage and charging units and the battery bidirectional buck-boost DC / DC interface circuit.

[0188] The VSG control algorithm is used for the generator set, the first AC mains grid and the first AC mains grid to cooperate with each other to supply power to the DC microgrid and the AC microgrid energy storage system PCS, achieving seamless switching.

[0189] In the early stage, the hybrid algorithm unit uses the voltage / current estimation method and the maximum current constant current corresponding fast charging for each battery module in the hybrid battery pack unit control platform. It is simple and the fast charging efficiency is improved by 50%, mainly because the test voltage and current are fast and the algorithm is simple and fast.

[0190] A variable time constant low-pass filter is used to smoothly switch to the SOC fuzzy control algorithm and the maximum current constant voltage corresponding to fast charging, which is simpler than the SOC adaptive control algorithm used in the existing technology, and the fast charging efficiency is improved by 35%. The algorithm is simple and fast; a variable time constant low-pass filter is used to smoothly switch to the floating charge stage, and the SOC adaptive control algorithm of the existing technology is used for precise control, and the charging speed is the same as that of the existing technology; the charging procedure of the hybrid algorithm unit is also used in the discharge stage, which can achieve 45% faster discharge than the existing technology. The energy storage battery pack power reserve management adopts SOC change control and battery voltage test management. In combination with the power over-limit protection module, the battery reserve management is more accurate and faster than the existing technology. Combined with the DC voltage + current + two-stage PI control + PWM control of the hybrid battery pack unit control platform, fast and accurate storage is achieved, and at the same time, fast charging and discharging management is achieved, reducing the charging times of multiple megawatt battery packs, preventing overcharging and over-discharging of the existing technology, and improving the battery life.

[0191] The battery voltage / current test module of the energy storage battery pack is composed of a smart grid voltage controller, a battery voltage controller, and a pulse modulator; the battery voltage / current test module of the energy storage battery pack realizes the algorithm of the battery pack DC and the smart grid (wind photovoltaic DC transmission) storage charge and discharge converter: including smart grid voltage control, battery ( Figure 1 The charging voltage and current of the BEMS, distributed photovoltaic storage charging and discharging stations, and batteries in the battery cabinet connected to the PCS are converted through a 5-level inductive non-isolated buck-boost bidirectional charger and discharger.

[0192] A control system for a large-scale distributed flexible wind, solar, storage, charging and discharge, and AC / DC hybrid system based on energy cloud interconnection, such as Figure 8a As shown, the battery pack DC and smart grid storage and discharge converter are controlled by a dual-loop control system. Specifically, the dual-loop control system is used to adjust the voltage input to the DC microgrid between the charging battery pack of the distributed wind storage charging and discharging station and the bidirectional buck-boost DC / DC interface circuit; the dual-loop control system is used to adjust the voltage input to the AC microgrid between the battery storage battery pack of the distributed photovoltaic charging and discharging station and the bidirectional buck-boost DC / DC interface circuit.

[0193] The dual-loop control system includes a smart grid voltage controller, a battery voltage controller, a pulse modulator, and a hybrid energy storage platform; the dual-loop control system consists of an external voltage loop (smart grid voltage) and an additional internal current loop (battery voltage controller + pulse modulator), and controls the input voltage through a current-voltage compensation mode.

[0194] In the smart grid voltage controller, when the battery voltage V bat The minimum acceptable battery voltage corresponding to the battery's safe SOC When the difference is greater than 0, the comparator output is set to the reference voltage of the first AC mains grid and the second AC mains grid. When the battery voltage V bat Less than The battery is at low SOC and does not have enough power to supply the total load. The comparator outputs the reference voltage of the DC or AC microgrid. The software program will reference the voltage Set to unload voltage V shat , to trigger the load shedding system. Microgrid (DC or AC) reference voltage The battery output voltage is similar to the actual SOC. Accordingly, some non-essential loads in the microgrid (DC or AC) are removed to save resources for sensitive loads.

[0195] The grid voltage V output by the 5-level DC conversion (diode clamped multi-level two-stage topology circuit) grid With microgrid (DC or AC) reference voltage Compare, The maximum value of the grid voltage selected by GS-VSC (battery-voltage source converter) is greater than the maximum value of the controlled grid voltage. C-grid , compensator G C-grid The output is sent to the negative limiter; in grid-connected mode, And the generated signal will be limited to zero by the negative limiter. In this case, the battery voltage controller controls the battery charging process, that is, the voltage control loop;

[0196] On the other hand, in renewable energy (i.e. Figure 1 In the case of microgrid (DC or AC) operation with insufficient power generation of distributed photovoltaic storage charging and discharging stations, distributed wind storage charging and discharging stations), the voltage control loop of the grid will use the battery reference voltage By controlling the forward rotation, when the negative limiter limit (the limit of the maximum positive and negative sequence current of the battery, the current has no negative sequence current) is zero, the control combination outer voltage loop generates the converter reference voltage For batteries ( Figure 5a The discharge of the battery provides compensation power. and battery voltage set point voltage Comparison, output battery reference voltage The reference voltage.

[0197] K aw represents the anti-saturation compensation coefficient, The battery output voltage is generated according to the SOC. If the battery voltage V bat <Minimum acceptable battery voltage The battery is at low SOC and does not have enough charge to supply the total load. In this case, Set to unload voltage V shat to trigger the load shedding system.

[0198] The input of the battery voltage controller is the battery reference voltage output by the smart grid voltage controller Battery reference voltage With the battery voltage V bat Compare, when the comparison result is greater than 0, the output voltage difference is sent to the battery voltage compensator G C-bat .

[0199] Battery voltage compensator G C-bat The output end is connected to the battery current limiter, and the charging selects the maximum battery charging current , discharge select maximum discharge current Battery current limiter outputs battery reference current

[0200] The pulse modulator includes: a battery bidirectional buck-boost DC / DC interface unit and a wind and solar storage and discharge unit. Figure 5b The battery current I bat and battery reference current As the input current of the pulse modulator, the equivalent impedance R L The inductor L generates the inductor current rising or falling slope compensation The equivalent impedance R0 and capacitor C0 on the battery output side generate the inductor current rising or falling slope compensation Adjust current rising or falling slope compensation

[0201] In the above formula, D represents the steady-state duty cycle of the inductor, T s is the period of the gate pulse, M s represents the synthetic slope for current slope compensation, L represents the inductor, and D′ represents the capacitor steady-state duty cycle.

[0202] The battery bidirectional buck-boost DC / DC interface unit is connected to the input of the pulse modulator through switch S16, and the wind-solar storage charge-discharge unit (wind-solar storage integrated system) is connected to the input of the pulse modulator through switch S15, sending the battery voltage I bat To the pulse modulator. The wind and solar storage and discharge unit outputs the battery voltage I bat To 5-level DC conversion, one path of the 5-level DC conversion is output to the DC bus (C1-C4 DC + multi-bit switch, AC + converter to all DC buses), and the other path of the 5-level DC conversion is output to the converter; multiple DC buses form a DC microgrid; the converter outputs to all AC buses, and multiple AC buses form an AC microgrid.

[0203] Grid reference voltage Grid compensation output voltage output by the pulse modulator Both are input to the first comparator. When the difference is negative, the first comparator outputs the voltage difference and starts the grid voltage compensator G C-grid , through the grid voltage compensator G C-grid Compensated voltage, battery output reference voltage Battery input combined output disturbance voltage Both are input to the second comparator, and the second comparator outputs the maximum voltage difference to the battery voltage compensator G C-bat Compensation, battery voltage compensator G C-bat Output compensation current, inductive disturbance current in battery model Input to the third comparator, the third comparator outputs the current difference; the current difference, the inductor current rise or fall slope compensation F b , the inductor current rising or falling slope compensation F0 are input to the fourth comparator, and the fourth comparator outputs the battery current rising or falling slope compensation F m ; Where D represents the steady-state duty cycle of the inductor, T s is the period of the gate pulse, M s represents the synthetic slope for current slope compensation, L represents the inductance, and D′ represents the steady-state duty cycle of the capacitor;

[0204] Adjust the current rise or fall slope compensation F according to the battery current m Determine the current duty cycle Input to duty cycle to inductor current transfer function G id ; Output disturbance current generated by R0 and C0 of the output filter Enter to Z in sequence L (Open-loop output current i0 to inductor current transfer function), Z i (Transfer function of open-loop output current i0 to input voltage).

[0205] Transfer function Z L , G id The output values ​​of are input to the fifth comparator, and the maximum value of the comparison is used as the output disturbance current of the inductor L Input to G bi , G bi is the transfer function from inductor current to input voltage, transfer function Z i The output value, transfer function G bi The output values ​​are input to the sixth comparator, and the maximum value of the comparison is used as the output synthetic disturbance voltage of the battery The output filter's R0 and C0 values ​​are input to the input-to-output voltage transfer function G 0b , voltage transfer function G 0b The output value of and the open-loop output resistance (excluding the load resistance) Z0 are input to the seventh comparator. The voltage and voltage transfer function G when the current command duty cycle is greater than 50% 0b The output value is compared, and the maximum value is used as the battery voltage and current peak slope to synthesize the compensation double loop control grid compensation output disturbance voltage

[0206] The battery voltage controller regulates the grid voltage in discharge mode during different disturbances for the worst operating conditions. The maximum charge current condition has a low bandwidth and the battery reference current The battery current I output by the distributed photovoltaic storage charging and discharging station bat As input, the inductor disturbance current in the battery model (i.e., bidirectional buck-boost DC / DC circuit) Real-time disturbance voltage and capacitor disturbance voltage As a state variable, the disturbance duty cycle and output disturbance current As input; the battery current limiter limits the current to the maximum battery charging current and discharge current value.

[0207] Duty cycle to inductor current transfer function in, Indicates the undisturbed open-loop current represents the disturbance duty cycle function, represents the inductor disturbance current function.

[0208] Transfer function from inductor current to input voltage in, represents the disturbance voltage function; represents the inductor disturbance current function.

[0209] Input to output voltage transfer function in, represents the output disturbance voltage function, represents the synthetic output disturbance voltage function, Indicates the undisturbed open-loop current and undisturbed duty cycle.

[0210] Open-loop output current to input voltage transfer function in, represents the synthetic output disturbance voltage function, represents the disturbed open-loop current function.

[0211] Open-loop output current to inductor current transfer function Among them, there is no synthetic output disturbance voltage Unperturbed open-loop current Z i0 represents the open-loop output current transfer function, R sb Represents the internal resistance of the battery, C tb represents the transient capacitance of capacitor C0, R tb Represents the transient resistance of the equivalent resistance R0.

[0212] Open-loop output impedance (excluding load resistance)

[0213] When the required power of the AC / DC hybrid utility system exceeds the power delivered by the PV-storage system, the DC bus voltage falls below the battery reference voltage, which is set to 0.95 times the battery energy storage reference voltage (PU). The load shedding voltage is set to 0.9 times the PU. The maximum power delivered by the PV-storage system exceeds the power of all sensitive loads in the DC microgrid. The PV array power equals the sum of the DC load power and the battery charging power. Some non-critical loads in the microgrid are shed, saving energy for sensitive loads. Anti-windup control is also implemented to compensate for saturation of the control variable, which often causes integral windup in controller implementations. The combination of these two voltage control loops is used to instantly balance system power and control grid voltage in the desired operating mode. Furthermore, when the maximum available battery discharge power falls below the required power, the load shedding system trips the required number of loads to prevent excessive battery discharge.

[0214] The existing technology is constant current + constant voltage charging, which is externally controlled by a current PI controller. The difference between the active power delivered to the grid and the reactive power support obtained by adjusting the phase angle is used as input for charging and discharging, and the active and reactive components of the current are used as output. It is not effective in preventing overcharging and over-discharging under the worst working conditions, and when the power is insufficient, the main load is prone to power outages. The battery pack DC and smart grid storage, charging and discharging converter of the embodiment of the present invention adopts a dual-loop control system of a voltage loop and an additional internal current loop. The smart grid voltage adopts compensation and negative limitation, and the battery voltage adopts compensation and current limitation. The converter reference voltage command is generated by controlling the combined outer voltage loop. The battery discharge is used to provide insufficient power, and the unimportant loads are reduced by triggering the unloading voltage to avoid excessive discharge of the battery and provide sufficient power for sensitive loads.

[0215] like Figure 1 、 Figure 12As shown, the working principle of the large-scale distributed flexible wind, solar, storage, charging and discharge, and AC / DC hybrid system of mains electricity based on energy cloud interconnection is supplemented; the operation of the photovoltaic, storage, and mains AC / DC hybrid charging pile system is divided into photovoltaic power generation and photovoltaic non-power generation, the first AC bus of the mains electricity, the second AC bus, the photovoltaic surplus power is connected to the grid, the photovoltaic inverter is rectified into DC and sent to the DC bus for power supply and energy storage charging, the energy storage discharge is for the DC pile, the DC bus power supply pile is for the load DC cabinet and the fire cabinet, the first AC bus is connected to the photovoltaic inverter system, the battery energy storage rectifier system, the station power room, and the second AC bus is for the lithium charger and AC charging pile, AC cabinet, and communication cabinet.

[0216] The primary and secondary mains power the primary and secondary AC busbars, while the PV inverter and primary and secondary mains power the generator. These two circuits, along with the automatic switching between AC and DC, and power transfer, are all achieved through the AC primary to secondary transfer switches and DC dual power conversion. Power consumption for AC, DC, mains, photovoltaics, and energy storage is measured using DC energy meters and bidirectional AC meters.

[0217] Photovoltaic power generation includes three situations: charging power is less than generating power, charging power is greater than generating power + energy storage discharge power, and generating power charging power is less than generating power + energy storage discharge power;

[0218] The charging power is less than the generating power, which is divided into two situations: the energy storage is not full and the energy storage is full. When the energy storage is not full, the motor generates electricity and the energy storage system charges and transmits it to the second AC bus for power supply and the AC pile lithium charger for power supply. When the energy storage is full, the surplus power is passed through the grid and connected to the grid for power generation, switching to the third dual power supply and supplying power to the second AC bus.

[0219] The charging power is greater than the power generation power + energy storage discharge power, and energy storage discharge + grid-connected power is used to power the DC pile and DC cabinet load, and the AC power is from the mains.

[0220] The charging power of the generated power is less than the generated power + the energy storage discharge power. Energy storage discharge is adopted and the DC pile uses electricity.

[0221] There are two situations where PV power is not generating electricity: charging power is greater than the energy storage discharge power, and charging power is less than the energy storage discharge power. When charging power is greater than the energy storage discharge power, grid-connected power is used, and the second AC busbar supplies power and the AC pile lithium charger consumes power. When charging power is less than the energy storage discharge power, the energy storage is discharged, charging the first AC busbar, and using power for the DC cabinet.

[0222] Figure 12 Its function is to achieve uninterrupted power supply. Compared with the existing technology, it adds a distributed photovoltaic storage and discharge station + generator set + automatic transfer switch + dual AC power supply.

[0223] like Figure 13As shown, the bidirectional charging and discharging high-frequency battery SOC remaining energy curve within 10 seconds of the megawatt-level battery energy storage is simulated. From 0 to 4s, the high-frequency battery remaining energy SOC drops from 50 to 49.2; from 4 to 8.5s, the high-frequency battery remaining energy SOC rises from 49.2 to 59.1; from 8.5 to 10s, the high-frequency battery remaining energy SOC drops from 50.1 to 50.

[0224] like Figure 14 As shown, the bidirectional charging and discharging low-frequency battery remaining energy SOC 10-second simulation curve of the megawatt-level battery energy storage is as follows: 0-7.5s, the low-frequency battery remaining energy SOC drops from 50.1 to 49.72; 7.5-10s, the low-frequency battery remaining energy SOC rises from 49.72 to 49.85.

[0225] like Figure 15 As shown, the bidirectional charging and discharging high-frequency battery charging and discharging current simulation curve within 10 seconds of megawatt-level battery energy storage is as follows: 0-1.2s, the high-frequency battery charging and discharging current rises from 0 to 100A; 1.2-2.8s, the high-frequency battery charging and discharging current drops from 100A to 5A; 2.8-3.5s, the high-frequency battery charging and discharging current rises from 5A to 180; 3.5-8.7s, the high-frequency battery charging and discharging current drops from 100A to 15A; 8.7-10s, the high-frequency battery charging and discharging current rises from 15A to 165A.

[0226] like Figure 16 As shown in the figure, the bidirectional charging and discharging high-frequency battery terminal voltage simulation curve of the megawatt-level battery energy storage within 10 seconds is as follows: 0-0.5s, the high-frequency battery terminal voltage drops from 1420V to 1300V; 0.5-1.5s, the high-frequency battery terminal voltage rises from 1300V to 1450V; 1.5-1.8s, the high-frequency battery terminal voltage drops from 1450 to 1220V; 1.8-8.7s, the high-frequency battery terminal voltage rises from 1220V to 1448V; 8.7-10s, the high-frequency battery terminal voltage drops from 1448V to 1300V.

[0227] like Figure 17 As shown, the bidirectional charging and discharging megawatt-level battery energy storage low-frequency battery charging and discharging current simulation curve within 10 seconds, 0-1.0s, the low-frequency battery charging and discharging current rises from -10A to 45A; 1.0-3.7s, the low-frequency battery charging and discharging current rises from 45A to 1220A; 3.7-8.3s, the low-frequency battery charging and discharging current drops from 1220A to 50A; 8.7-10s, the low-frequency battery charging and discharging current rises from 50A to 75A.

[0228] like Figure 18As shown in the figure, the bidirectional charging and discharging low-frequency battery terminal voltage simulation curve of megawatt-level battery energy storage within 10 seconds is as follows: 0-5.5s, the low-frequency battery terminal voltage drops from 1450V to 1030V; 5.5-9.2s, the low-frequency battery terminal voltage rises from 1030V to 1440V; 9.2-10s, the low-frequency battery terminal voltage drops from 1440V to 1430V.

[0229] According to the simulation verification of the smooth output of the three intervals of the above five-level DC voltage-equalizing (positive and negative levels) multi-phase chopped wave optical storage and charge-discharge circuit, the system initial voltage = 10kV, active power P = -2MW, reactive power Q = 0Var, frequency = 50Hz; when the system runs for 2s, the following fluctuations occur; the simulation verification of the voltage regulation and emergency power support functions implemented by the smart grid is as follows:

[0230] (1) The 5-level DC voltage-equalizing (positive and negative voltage) multi-phase chopped wave optical storage and discharge system experienced a 10%, 15%, and 10% voltage drop in the smart grid at 2 seconds. The reactive power increased from 0 to 0.4Mvar, 0.5Mvar, and -0.3Mvar, respectively, providing reactive power support to the smart grid. The active power increased slightly and then fell back to 2MW. The system added 0.5MW of active output to the smart grid within 0.1 seconds.

[0231] (2) The system operates in different active and reactive states: P = -2.0MW, Q = 0var; P = -1.5MW, Q = 0var; P = -1.5MW, Q = 0.2Mvar. The simulation shows that when the grid frequency drops by 10%, the energy storage system can provide reactive power support of 0.3Mvar and 0.1Mvar to the smart grid through 0.1V voltage regulation. The active power increases slightly and then drops back to 2WM.

[0232] (3) The system stores energy in different charge and discharge states, with the initial system voltage = 10KV, active power P = 2MW, reactive power Q = 0Var, and frequency = 50HZ. When the system runs for 2s, the grid frequency drops by 10% and rises by 10%. After voltage regulation within 0.2S and 0.1S, the energy storage system provides reactive power support of 0.3Mvar and -0.2Mvar to the grid. The active power is maintained within an acceptable range.

[0233] (4) The energy storage system is operated under different short-circuit ratios (SCR = 3 or 8). The initial system voltage is 10KV, the active power P is 2MW, the reactive power Q is 0Var, and the frequency is 50HZ. When the system runs for 2s, the grid frequency drops by 10%. The energy storage system regulates the voltage within 0.2S and 0.1S, providing reactive support to the grid. The active power is maintained within an acceptable range.

[0234] (5) The energy storage system is in different initial states of the energy storage battery (SOC = 0.3 or 0.8 with discharge margin), the system initial voltage = 10KV, active power P = 2MW, reactive power Q = 0Var, frequency = 50HZ; when the system runs for 2s, the grid frequency drops by 10%, and the energy storage system provides reactive support to the grid through voltage regulation within 0.1S; the active power is maintained within an acceptable range.

[0235] (6) The energy storage system in different energy storage battery initial states (SOC = 0.3 or 0.8 with discharge margin) has the following characteristics: system initial voltage = 10KV, active power P = -2MW, reactive power Q = 0Var, frequency = 50HZ; after receiving the emergency power support command, it is adjusted to the full discharge state: P = 2MW. The energy storage system in different charge and discharge states, the energy storage system in different short circuit ratios (SCR = 3 or 8), and the energy storage system in different energy storage battery initial states (SOC = 0.3 or 0.8 with discharge margin) can complete the increase of active output from -2MW to 2.5MW to the smart grid within 0.5 seconds; the reactive power remains unchanged; the peak-valley yield rate can reach more than 40%, and the peak shaving and valley filling can be realized, and the peak-valley electricity price difference can be smoothed (4.0:1 ratio). Configuring energy storage can smooth output and meet network-related technical requirements; grid-side energy storage can serve as power supply support and provide peak-shaving and other functional guarantees; industrial and commercial users can use low storage and high generation to reduce electricity costs; ordinary users can improve power supply reliability, but when the power supply from the grid is reliable, the demand is not urgent.

[0236] The frequency regulation and peak regulation functions of smart grids are verified by simulation:

[0237] (1) The system is within 2s-2.5s. The frequency drops by 0.2-0.3HZ respectively, and the system adds 0.4MW and 0.6MW to the smart grid respectively. The reactive power increases slightly and then falls back to 0. The frequency rises by 0.2HZ, and the system reduces the active output of 0.4MW to the smart grid within 0.25 seconds. The reactive power remains unchanged at 0.

[0238] (2) The system is in different active and reactive states. When the grid frequency drops by 0.2Hz-0.25s, the energy storage system can adjust the frequency within 2s-2.5s, and it can provide active support to the grid. The reactive power remains unchanged at 0.

[0239] (3) The energy storage system is under different charge and discharge states. When the grid frequency drops by 0.2HZ-0.25s, the energy storage system can adjust the frequency within 2s-2.5s, and can provide active power support for the grid; the reactive power is maintained within an acceptable range.

[0240] (4) The energy storage system can provide active power support to the grid under different short-circuit ratios (SCR = 3 or 8). When the grid frequency drops by 0.2HZ-0.25s, the energy storage system can adjust the frequency within 2s-2.5s. The reactive power is maintained within an acceptable range.

[0241] (5) Under different initial states of the energy storage battery (SOC = 0.3 or 0.8 with discharge margin), the energy storage system can provide 0.4MW of active power support to the grid when the grid frequency drops by 0.2Hz-0.25s and the energy storage system adjusts the frequency within 2s-2.5s. This reduces the degree of grid drop and maintains the reactive power within an acceptable range.

[0242] (6) The system is within 2s-2.5s. The initial system P = 1MW, 0.5WM; after receiving the peak-shaving command, the energy storage system in different active and reactive states, different charge and discharge states, different short-circuit ratios (SCR = 3 or 8) states, and different initial states of the energy storage battery (SOC = 0.3 or 0.8 with discharge margin) states respectively adds peak-shaving power P = 2MW to the smart grid in 2.5S (0.5S) and maintains the system at 2MW (from 1MW to 2.0 active output completed within 0.5 seconds), and the reactive power remains unchanged; the peak-valley yield rate can reach more than 45%, achieving peak shaving and valley filling, and smoothing the peak-valley electricity price difference (4.5:1 ratio). Configuring energy storage can smooth output and meet network-related technical requirements; grid-side energy storage can serve as power supply support and provide peak-shaving and other functional guarantees; industrial and commercial users can use low storage and high generation to reduce electricity costs; ordinary users can improve power supply reliability, but when the power supply from the grid is reliable, the demand is not urgent.

[0243] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A large-scale distributed flexible wind, solar, storage, charging, and discharge system for AC and DC hybrid use of city power based on energy cloud interconnection, characterized by: Including complementary multi-megawatt battery energy storage converters and wind-solar storage integrated systems, transformerless high-voltage direct-mounted battery energy storage power conversion systems, AC microgrids, and DC microgrids; among them, The multi-megawatt battery energy storage converter is used to store energy and perform bidirectional charging on multi-megawatt batteries; The wind-solar-storage integrated system is used to integrate a multi-megawatt photovoltaic battery energy storage converter and a multi-megawatt wind battery energy storage converter into the same system to achieve energy storage, bidirectional charging and discharging functions; The transformerless high-voltage direct-mounted battery energy storage power conversion system is used to achieve flexible switching between low-voltage and high-voltage systems and directly access the high-voltage power supply system through transformerless high-voltage direct-mounted battery energy storage power conversion; The AC microgrid and DC microgrid are used to flexibly access the smart grid to achieve mixed use of AC and DC mains power; The smart grid comprises: a pair of first AC mains power grid and second AC mains power grid arranged in parallel; The wind-solar-storage integrated system includes: a distributed solar-storage charging and discharging station and a distributed wind-storage charging and discharging station; The AC microgrid includes a first AC bus, a second AC bus, and a third AC bus; The DC microgrid includes a first DC bus and a second DC bus; Among them, the first AC mains grid supplies power to the first AC bus, the second AC mains grid or the distributed flexible photovoltaic storage charging and discharging station supplies power to the generator set, and the generator output end and the second AC mains grid supply power to the second AC bus; the distributed photovoltaic storage charging and discharging station supplies power to the first AC bus, and the distributed flexible photovoltaic storage charging and discharging station is used for emergency power supply after the AC mains power outage; The first AC bus is connected to the first AC mains grid and the second AC mains grid via a first automatic transfer switch. The first AC bus is connected to the first DC bus and the second DC bus respectively via corresponding rectifiers. The first AC bus is also connected to the energy storage component via a rectifier and is connected to the motor room of the power station. The PCS system connected to the first DC bus is connected to the first AC bus via a rectifier and a smart meter. The input end of the second AC bus is connected to the generator set via a second automatic transfer switch, the generator set is connected to the first AC mains grid and the second AC mains grid via a first automatic transfer switch, the first AC mains grid and the second AC mains grid are switched via a third automatic transfer switch, and the second automatic transfer switch is connected to the output end of the distribution transformer on the second AC mains grid; the common output end of the first AC mains grid and the second AC mains grid is connected to the distribution transformer; the output end of the second AC bus is connected to the AC load; The third AC bus is connected to multiple megawatt-class wind turbine converters; the third AC bus is connected to the first AC bus via a fourth automatic transfer switch; the third AC bus is connected to the DC microgrid via a rectifier to provide power supply; The battery cabinet is connected to the PCS system and the first DC bus through a bidirectional buck-boost DC / DC interface circuit to achieve DC power supply. The first DC bus is connected to the corresponding DC pile and DC cabinet through a DC meter. The second DC bus is connected to multiple megawatt-class multi-stage energy storage battery packs in the distributed wind storage charging and discharging station through a bidirectional buck-boost DC / DC interface circuit; The first DC bus and the second DC bus are connected via a sixth automatic transfer switch.

2. According to claim 1, a large-scale distributed flexible wind, solar, storage, charging, and discharge system based on energy cloud interconnection, characterized in that: The transformerless high-voltage direct-mounted battery energy storage power conversion system includes a transformerless high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion light-storage charging and discharging circuit; the AC / DC module in each wind power converter of the distributed wind storage charging and discharging station is connected to the transformerless high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion light-storage charging and discharging circuit through a transfer switch, and then connected to the public contact of the second AC city power grid through a switch.

3. According to claim 2, a large-scale distributed flexible wind, solar, storage, charging, and discharge system based on energy cloud interconnection, characterized in that: The transformerless high-voltage / low-voltage compatible direct-mounted battery energy storage power conversion light storage charge-discharge circuit includes an energy storage battery group, which is composed of energy storage batteries Cell1 to Cell5 connected in series. The negative end of the fifth battery Cell5 is connected to a fuse FU4, and the fuse FU4 is connected to the 0th DC circuit. The positive end of the first battery Cell1 is respectively connected to the A, B, and C three-phase circuits with the same structure; in the A phase circuit, the positive input end of the first battery Cell1 is sequentially connected to the fuse FU1 and the switch S37, and both ends of the switch S37 are connected. A series circuit of a switch S36 and a pre-charge resistor R10 is connected in parallel. Series capacitors C1, C2, C3, and C4 are connected between the output end of the switch S37 and the negative electrode of the fifth battery Cell5. The two ends and the series nodes of the series capacitors C1, C2, C3, and C4 are connected in parallel to five-level DC busbars, outputting five equal-flow DC currents. The negative electrode of the fifth battery Cell5, the series node of the two adjacent capacitors, and the positive electrode of the first-level battery Cell1 correspond to the 0th, 1st, 2nd, 3rd, and 4th DC paths, respectively, and the output currents are i 5A 、i 4A 、i 3A 、i 2A 、i 1A ; Phase A DC current i 1A SiC MOSFET transistor S connected to the A-phase inverter / rectifier unit A1 、S A4 The series circuit, current i 2A Enter the SiC MOSFET transistor S A2 、S A3 The series circuit, current i 4A Enter the SiC MOSFET transistor S' A2 , S′ A3 The series circuit, current i 5A Enter the SiC MOSFET transistor S' A1 , S′ A4 Series circuit of diode D A1 Clamped on transistor S A1 、S A4 The series junction of diode D ′ A1 The reverse clamp is located on transistor S' A1 , S′ A4 The series junction of diode D A2 Clamped on transistor S A2 、S A3 The series junction of diode D ′ A2 The reverse clamp is located on transistor S' A2 , S′ A3 The series node of 3A Pass diode D A2 , diode D ′ A2 The series junction of transistor S ′ A2 、S A3 The series junction of the diode D A1 , diode D ′ A1 The series node connection of transistor S' A1 With transistor S A4 The connected midpoint outputs the A-phase AC current i A ; The series connection point of capacitors C1 and C2 is connected to the inductor end of the R1L1 filter through the connecting line Cel3, the resistor end of the R1L1 filter is connected to the emitter of transistor S1, and the collector of transistor S1 is connected to the fourth DC path; the series connection point of capacitors C3 and C4 is connected to the inductor end of the R3L3 filter through the connecting line Cel1, the resistor end of the R3L3 filter is connected to the emitter of transistor S3, and the collector of transistor S3 is connected to the fourth DC path; the emitter of transistor S3 is connected to the output of diode D33. The input end of the diode D33 is connected to the negative electrode of the fifth battery Cell5; the series node of the capacitors C2 and C3 is connected to the inductor end of the R2L2 filter through the connecting line Cel2, the resistor end of the R2L2 filter is connected to the emitter of the transistor S2, the resistor end of the R2L2 filter is connected to the output end of the diode D22, the emitter of the transistor S2 is connected to the output end of the diode D22, the collector of the transistor S2 is connected to the fourth DC path, and the input end of the diode D22 is connected to the connecting line Cel1; Through the same three-phase circuit, the B-phase DC current at the positive terminal of the first battery Cell1 is converted into the B-phase AC current i B , the C-phase DC current at the positive terminal of the first battery Cell1 is converted into the C-phase AC current i C ; The neutral point of the output terminal of the A-phase inverter / rectifier unit is connected to a two-position switch S33, one of which is connected to R a L a Filter connection, R a L a The filter output is connected to the common point of the smart high-speed grid through fuse FU5 and to the A-phase 0 DC circuit through switch S30. The other end of the dual-position switch S33 is connected to the negative output terminal of the C-phase inverter / rectifier unit, forming a series connection between the A-phase circuit and the C-phase circuit. The neutral point of the output terminal of the B-phase inverter / rectifier unit is connected to a two-position switch S34. One path of the two-position switch S34 is connected to R b L b Filter connection, R b L b The filter output is connected to the common point of the smart high-speed grid through fuse FU5, and is connected to the B phase 0 DC circuit i through switch S31. 5B The other side of the double-position switch S34 is connected to the negative electrode of the output terminal of the A-phase inverter / rectifier unit, forming a series connection of the B-phase circuit and the A-phase circuit; The neutral point of the output terminal of the C-phase inverter / rectifier unit is connected to a two-position switch S35. One path of the two-position switch S35 is connected to R c L c Filter connection, R c L c The filter output is connected to the common point of the smart high-speed grid through fuse FU5, and is connected to the C phase 0 DC circuit i through switch S32. 5C The other side of the double-position switch S35 is connected to the negative electrode of the output terminal of the B-phase inverter / rectifier unit, forming a series connection of the C-phase circuit and the B-phase circuit; When controlling the double position switch S33 and R a L a Filter connection, while the switch S30 is closed; control the double position switch S34 and R b L b Filter connection, while the switch S31 is closed; control the double position switch S35 and R c L c The filter is connected and the switch S32 is closed at the same time; the A phase circuit, the B phase circuit, and the C phase circuit are all independent low-voltage circuits to achieve low-voltage fast charging; When the dual-position switch S33 is connected to the negative output terminal of the C-phase inverter / rectifier unit, forming a series connection between the A-phase circuit and the C-phase circuit, the switch S30 is disconnected, the A-phase high-voltage output circuit is connected, and the switch S32 is disconnected. When the dual-position switch S34 is connected to the negative output terminal of the A-phase inverter / rectifier unit, forming a series connection between the B-phase circuit and the A-phase circuit, the switch S31 is disconnected and the B-phase high-voltage output circuit is connected; at this time, the switch S30 is disconnected; When the dual-position switch S35 is controlled to be connected to the negative electrode of the output terminal of the B-phase inverter / rectifier unit, forming a series connection of the C-phase circuit and the B-phase circuit, the switch S32 is disconnected and the C-phase high-voltage output circuit is connected; at this time, the switch S31 is disconnected.

4. According to claim 2, a large-scale distributed flexible wind, solar, storage, charging, and discharge system based on energy cloud interconnection, characterized in that: The multi-quadrant converter and UPS inverter in the distributed photovoltaic storage charging and discharging station both adopt a diode-clamped multi-level two-stage topology circuit, which has the functions of inversion and rectification; the diode-clamped multi-level two-stage topology circuit includes multiple capacitors connected in series, which are connected between the positive and negative electrodes of the energy storage battery pack, and the multiple capacitors connected in series are connected to the energy storage battery pack via a bidirectional buck-boost circuit; The bidirectional buck-boost circuit includes multiple sets of electronic multi-position conversion switches, which are connected to multiple capacitors in series. The positive electrodes of multiple inductive non-isolated buck-boost bidirectional chargers with the same structure are connected to the positive electrodes of the corresponding electronic multi-position conversion switches, and the negative electrodes are connected to the negative electrodes of the corresponding electronic multi-position conversion switches. Each inductive non-isolated buck-boost bidirectional charger and discharger charges and discharges the corresponding energy storage battery in the energy storage battery pack, where the capacitor C a 3 One end is connected to the control line P1, capacitor C a 3 The other end is connected to the G pole of MOSFET tube Q1, and the D pole lead of MOSFET tube Q1 is connected to the resistor R a 1 one end is connected to the resistor R a The other end of 1 is connected to the capacitor C a 3 and the G pole of MOSFET tube Q1; the S pole lead of MOSFET tube Q1 is connected to the D pole of MOSFET tube Q2, and the G pole lead of MOSFET tube Q2 is connected to the capacitor C a 4 one end is connected to capacitor C a 4 The other end is connected to the control line P2, and the S-pole lead of the MOSFET tube Q2 is connected to the resistor R A 2 one end connected to the resistor R A 2The other end is connected to capacitor C a 4 and the G-pole lead of MOSFET tube Q2; a capacitor C is connected in series between the D-pole lead of MOSFET tube Q1 and the S-pole lead of MOSFET tube Q2. a 2 and capacitor C a 1. The D-pole lead of MOSFET tube Q1 is used as the positive pole of the energy exchange driving power supply and is connected to the positive pole of the electronic multi-position switch; Resistor R a 9 and inductor L a 1 One end of the parallel node is connected between MOSFET tube Q1 and MOSFET tube Q1, and the resistor R a 9 and inductor L a The other end of the parallel connection point is connected to the capacitor C a 2 and capacitor C a 1 series node; capacitor C a 2 and capacitor C a The lead wire of the series node of 1 is used as the negative electrode of the energy exchange driving power supply and is connected to the negative electrode of the electronic multi-position switch; Capacitor C a 2 and capacitor C a The lead wire of the series node of 1 serves as the positive terminal of an energy storage battery Cell1 in the energy storage battery pack, and the S-pole lead wire of the MOSFET tube Q2 serves as the negative terminal of the energy storage battery Cell1; The inductive non-isolated buck-boost bidirectional charger and discharger corresponding to each energy storage battery in the energy storage battery pack has the same structure.

5. According to claim 1, a large-scale distributed flexible wind, solar, storage, charging, and discharge system based on energy cloud interconnection, characterized in that: The PCS system is connected to the battery cabinet via a bidirectional buck-boost DC / DC interface circuit, and the battery cabinet is connected to the DC microgrid via a bidirectional buck-boost DC / DC interface circuit; the batteries in the distributed wind storage charging and discharging station are connected to the DC microgrid via a bidirectional buck-boost DC / DC interface circuit; the battery energy storage battery pack of the distributed solar storage charging and discharging station is connected to the DC microgrid via a bidirectional buck-boost DC / DC interface circuit; The bidirectional buck-boost DC / DC interface circuit includes a battery, an inductor L and a resistor R of a converter input filter. L The inductor L is connected in series with the positive output line of the battery. The output end of the inductor L is connected to the S pole of the first MOSFET tube and the D pole of the second MOSFET tube respectively. The D pole of the first MOSFET tube is connected to the corresponding negative output line of the battery. The output filter resistor R is connected in series between the S pole of the second MOSFET tube and the negative pole of the battery. o , capacitor C o , a switch S is connected between the positive and negative poles of the battery B and capacitor C B , switch S B With capacitor C B Connect in series; the S pole of the second MOSFET tube and the resistor R o The output current between them is used as the positive voltage electrode and connected to the positive electrode of the corresponding DC microgrid; the capacitor C o The output current of the connection end with the negative output line of the battery is used as the negative pole of the voltage and is connected to the corresponding negative pole of the DC microgrid.

6. According to claim 1, a large-scale distributed flexible wind, solar, storage, charging, and discharge system based on energy cloud interconnection, characterized in that: The wind-solar-storage integrated system also includes a hybrid energy storage platform; Power bus output total power P w The measured values ​​of the current and voltage sensors connected to the output end of the power bus are used to calculate the reference power through the power software and input into the energy storage hybrid power distribution unit. The energy storage hybrid power distribution unit sends the reference power output to the hybrid algorithm unit. The hybrid algorithm unit combines the wind, solar and storage planned output to output the first distribution power; the output end of the hybrid algorithm unit is connected to the I-type low-pass filter, and the second distribution power output by the I-type low-pass filter and the first distribution power output by the hybrid algorithm unit are both input into the first comparator. The first comparator is used to correct the difference between the two distribution powers to obtain the classified power and send it to the converter power voltage control module. The converter power voltage control module outputs the actual energy storage power to the hybrid energy storage platform through the DC / AC conversion module. The classified power output by the first comparator and the first allocated power output by the hybrid algorithm unit are both input to the second comparator, which then outputs the planned classified power to the hybrid battery pack unit to perform planned control on the megawatt-class battery pack module. The classified power output by the first comparator is fed back to the hybrid algorithm unit, and the hybrid battery pack unit sends the remaining power of the complementary battery pack to the hybrid energy storage platform. The hybrid energy storage platform inputs the actual power of the complementary battery pack into the master-slave controller, which includes an active and reactive power droop PQ control module and a voltage and frequency droop V / f control module; the active and reactive power droop PQ control module is used for the master-slave integrated flexible wind and solar storage and charging and discharging integrated platform to be grid-connected to the municipal power grid; the voltage and frequency droop V / f control module is used for the master-slave integrated flexible wind and solar storage and charging and discharging integrated platform to power the DC microgrid and the AC microgrid; The input end of the master-slave controller is connected to the grid synchronization signal measurement module through an electronic switching switch S22, and the electronic switching switch S22 is used to switch between the grid and the microgrid; the grid synchronization signal measurement module is connected to the DC microgrid and the AC microgrid respectively through the switches at the common connection points of the first AC mains grid and the second AC mains grid, and the DC microgrid and the AC microgrid are connected through a multi-position transfer switch and an AC / DC conversion module; the output end of the master-slave controller is connected to the hybrid battery pack unit and the UI measurement module respectively through the DC / AC conversion module to provide real-time parameters for power calculation.

7. A large-scale distributed flexible wind, solar, storage, charging, and discharge, AC and DC hybrid system based on energy cloud interconnection according to claim 6, characterized in that: It also includes an SOC conversion control module, which sends the battery remaining capacity to the hybrid algorithm unit and the electric energy over-limit protection unit respectively; the battery current and voltage test module sends the tested voltage and current values ​​to the hybrid algorithm unit and the electric energy over-limit protection unit respectively; the electric energy over-limit protection unit sends the over-limit parameters to the hybrid battery pack unit control platform; the hybrid battery pack unit control platform includes a megawatt-level lithium iron phosphate battery pack, a supercapacitor and lead-acid battery pack, a lithium battery pack, a lead-acid battery pack, a sodium-sulfur battery pack, an MH-Ni battery pack, a lithium aggregate battery pack, an all-vanadium liquid battery pack, and a DC voltage + current + PWM plan control module; the hybrid battery pack unit control platform controls the remaining amount of the corresponding battery energy storage through a DC voltage + current + PWM plan.

8. A large-scale distributed flexible wind, solar, storage, charging, and discharge, AC and DC hybrid system based on energy cloud interconnection according to claim 6 or 7, characterized in that: The hybrid algorithm unit includes an SOC adaptive algorithm module, an SOC fuzzy control algorithm module, a VGA control algorithm module and a voltage / current estimation method module; the energy storage hybrid power distribution unit is connected to the SOC adaptive algorithm module, the SOC fuzzy control algorithm module, the VGA control algorithm module and the voltage / current estimation method module respectively through a multi-position electronic switching switch; each algorithm module in the hybrid algorithm unit is connected to a type I low-pass filter through a multi-position electronic automatic switching switch.

9. A control system for a large-scale distributed flexible wind, solar, storage, charging, and discharge utility power AC / DC hybrid system based on energy cloud interconnection as claimed in claim 6, characterized in that: Including smart grid voltage controller, battery voltage controller, pulse modulator, hybrid energy storage platform; The smart grid voltage controller includes a comparator, a compensator, and a negative limiter. When the battery voltage V bat The minimum acceptable battery voltage corresponding to the battery's safe SOC When the difference is greater than 0, the comparator output is set to the reference voltage of the first AC mains grid and the second AC mains grid. When the battery voltage V bat Less than The battery is at low SOC and does not have enough power to supply the total load. The comparator outputs the reference voltage of the DC or AC microgrid. Set the reference voltage Set to unload voltage V shat , to trigger the load reduction system; DC microgrid or AC microgrid reference voltage Generate output voltage corresponding to the actual battery SOC; unimportant loads in the DC or AC microgrid are removed, saving resources for sensitive loads; The grid voltage V output by the diode clamped multi-level two-stage topology circuit grid Reference voltage of DC or AC microgrid Compare, The maximum value selected by the battery-voltage source converter is greater than the maximum value of the controlled grid voltage; the maximum value is input to the grid voltage compensator G C-grid , compensator G C-grid The output is sent to the negative limiter; in grid-connected mode, The generated signal is limited to zero by the negative limiter; in this case, the battery voltage controller controls the battery charging process, i.e., the voltage control loop; When the distributed photovoltaic storage charging and discharging station and the distributed wind storage charging and discharging station generate insufficient power, the voltage control loop will set the battery reference voltage By controlling the direction to positive rotation and the negative limiter to zero, the control combination outer voltage loop generates the converter reference voltage Provides compensation power for battery discharge; converter reference voltage and battery voltage set point voltage Comparison, output battery reference voltage The battery voltage controller includes a comparator, a battery voltage compensator G C-bat , battery current limiter, battery reference voltage output by smart grid voltage controller With the battery voltage V bat Compare, when the comparison result is greater than 0, the output voltage difference is sent to the battery voltage compensator G C-bat ;Battery voltage compensator G C-bat The output end is connected to the battery current limiter, and the charging selects the maximum battery charging current Discharge selection maximum discharge current Battery current limiter outputs battery reference current Battery Current I in a Bidirectional Buck-Boost DC / DC Interface Circuit bat and battery reference current As the input current of the pulse modulator, the equivalent impedance R L The inductor L generates the inductor current rising or falling slope compensation F b , the resistor R0 and capacitor C0 of the output filter generate the inductor current rising or falling slope compensation F0 input pulse modulator; The battery bidirectional buck-boost DC / DC interface unit and the wind-solar-storage integrated system are connected to the input of the pulse modulator through the corresponding switch, sending the battery voltage I bat to the pulse modulator; Grid reference voltage Grid compensation output voltage output by the pulse modulator Both are input to the first comparator. When the difference is negative, the first comparator outputs the voltage difference and starts the grid voltage compensator G C-grid , through the grid voltage compensator G C-grid Compensated voltage, battery output reference voltage Battery input combined output disturbance voltage Both are input to the second comparator, and the second comparator outputs the maximum voltage difference to the battery voltage compensator G C-bat Compensation, battery voltage compensator G C-bat Output compensation current, inductive disturbance current in battery model input to the third comparator, and the third comparator outputs the current difference; Current difference, inductor current rise or fall slope compensation F b , the inductor current rising or falling slope compensation F0 are input to the fourth comparator, and the fourth comparator outputs the battery current rising or falling slope compensation F m ; Where D represents the steady-state duty cycle of the inductor, T s is the period of the gate pulse, M s represents the synthetic slope for current slope compensation, L represents the inductance, and D' represents the steady-state duty cycle of the capacitor; Based on the battery current rising or falling slope compensation F m Determine the current duty cycle Current transfer function G from input to inductor L id ; Output disturbance current generated by the output filter's resistor R0 and capacitor C0 Enter to Z L 、Z i , Z L is the current transfer function from the open-loop output current i0 to the inductor L, Z i is the transfer function from the open-loop output current i0 to the input voltage; Transfer function Z L , G id The output values ​​of are input to the fifth comparator, and the maximum value of the comparison is used as the output disturbance current of the inductor L Input to G bi , G bi is the transfer function from inductor current to input voltage, transfer function Z i The output value, transfer function G bi The output values ​​are input to the sixth comparator, and the maximum value of the comparison is used as the output synthetic disturbance voltage of the battery The battery output side R0 and c0 are both input to G 0b , G 0b is the voltage transfer function from input to output G 0h , transfer function G 0b The output value and the open-loop output resistance Z0 are input to the seventh comparator, Z0 does not include the load resistance; the voltage and transfer function G when the current command duty cycle is greater than 50% 0b The output value is compared, and the maximum value is used as the battery voltage and current peak slope to synthesize the compensation double loop control grid compensation output disturbance voltage Current command duty cycle = +D; based on the disturbance voltage during different disturbances Regulate the grid voltage according to the discharge mode.

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