V2G-based microgrid framework on ocean floating island and test method

Abstract

The invention discloses a V2G-based microgrid architecture on an ocean floating island. The V2G-based microgrid architecture comprises an alternating current side system, a direct current side system and an alternating current-direct current conversion management system, the direct-current side system comprises a battery energy storage system, a wind power / photovoltaic power generation system, a fuel cell power generation system and a direct-current hydrogen production system which are connected to a direct-current power grid; the battery energy storage system comprises a power grid system inherent battery energy storage station and a vehicle energy storage battery connected to a direct current charging station. The direct-current hydrogen production system is used for electrolyzing water to produce hydrogen and storing the hydrogen when the generating capacity of the wind power / photovoltaic power generation system is surplus; the fuel cell power generation system is used for generating power by using hydrogen when electric quantity is insufficient; the AC-DC conversion management system is used for mutual conversion of electric energy between the AC side system and the DC side system. A three-stage energy stabilization system which takes a battery energy storage station as a main part, a direct current hydrogen production system and a fuel cell as auxiliary parts and an energy storage battery of a vehicle as a standby part is adopted, so that the stability and the reliability of the micro-grid are effectively improved.

Description

Technical Field

[0001] The present invention relates to a microgrid construction method, and in particular to a V2G-based microgrid architecture and testing method on an ocean floating island. Background Art

[0002] Ocean floating islands are a new type of offshore equipment. They can be built into various functional platforms according to needs, such as science and technology research and development centers, maritime cultural centers and maritime museums. Ocean floating islands are often equipped with a variety of land equipment, surface equipment and underwater equipment. However, due to the special location of the ocean floating island, the microgrid installed on it cannot be connected to the grid and must operate off the grid. At the same time, the difficulty and cost of refueling are high. These devices usually operate in electric form. Unlike large land areas that require alternating current to transport electricity over long distances, ocean floating islands are relatively small in area. Direct current is used to directly charge batteries, and building a direct current power grid is an energy-saving behavior.

[0003] Existing ocean floating island microgrids often include non-traditional distributed energy sources, such as wind power, photovoltaics, fuel cells, etc. Microgrids combine generators, loads, energy storage devices and controls to form a single controllable independent power supply system, effectively utilizing distributed power sources and reducing dependence on traditional energy.

[0004] Although this kind of ocean floating island microgrid still has the following defects:

[0005] 1. The randomness and volatility of wind and solar power output will bring challenges to the economic and safe operation of microgrids under high penetration rates. When microgrids are off-grid, they can only rely on themselves to supply power to loads and absorb wind and solar power, and cannot trade electricity with large power grids. Therefore, the volatility of wind and solar power output will have a more serious impact on microgrids.

[0006] 2. The randomness and volatility brought by the charging demand of electric vehicles further reduce the stability of microgrid operation.

[0007] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the application, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art of microgrid operation with large volatility and low stability, and to provide a V2G-based microgrid architecture and testing method on an ocean floating island with small volatility and high stability.

[0009] To achieve the above objectives, the technical solution of the present invention is:

[0010] A V2G-based microgrid architecture on an ocean floating island, comprising: an AC side system, a DC side system and an AC / DC conversion management system;

[0011] The DC side system includes a battery energy storage system connected to the DC power grid, a wind power / photovoltaic power generation system, a fuel cell power generation system and a DC hydrogen production system;

[0012] The battery energy storage system includes: a battery energy storage station inherent in the power grid system and an energy storage battery of a vehicle connected to a DC charging station; the battery energy storage system is used to stabilize the energy supply of the power grid by using the battery energy storage station to "cut peaks and fill valleys", and the battery energy storage system is used to charge the energy storage battery of the vehicle using the DC charging station, and when the set conditions are met, the energy storage battery of the vehicle can be used to reversely supply power to the power grid;

[0013] The wind power / photovoltaic power generation system is an offshore floating island wind power / photovoltaic power generation array;

[0014] The DC hydrogen production system is used to electrolyze water to produce hydrogen for storage when the wind power / photovoltaic power generation system has surplus power generation;

[0015] The fuel cell power generation system is used to generate electricity using hydrogen when there is a shortage of electricity;

[0016] The AC / DC conversion management system is used for mutual conversion of electric energy between the AC side system and the DC side system.

[0017] The energy storage batteries of the transportation means include energy storage batteries on electric cars, ships, diving equipment and energy storage batteries on other power source ships.

[0018] The AC system includes an AC generator, a reactive load device, an active load device and a power quality monitoring device. The reactive load device and the active load device are connected in series with the power quality monitoring device and then connected to the AC / DC conversion management system;

[0019] The reactive load device is used to compensate reactive power, the active load device is used to consume active power, and the power quality monitoring device is used to monitor and adjust the active and reactive power balance in the AC power grid.

[0020] The direct current hydrogen production system includes an electrolyzer and a gas storage device. The electrolyzer is used to use excess electricity to electrolyze water to produce hydrogen and oxygen, and the gas storage device is used to store hydrogen and oxygen respectively.

[0021] The AC / DC conversion management system includes a power conversion main circuit and a power conversion control circuit.

[0022] The power conversion main circuit comprises: an inverter and power factor correction circuit and a CLLC resonant cavity circuit, wherein the AC side of the inverter and power factor correction circuit is connected to the AC grid, the DC side of the inverter and power factor correction circuit is connected to a 400V DC bus, one side of the CLLC resonant cavity circuit is connected to the 400V DC bus, and the other side of the CLLC resonant cavity circuit is connected to the DC grid;

[0023] The CLLC resonant cavity module is used to optimize energy transmission efficiency by adjusting the resonant frequency in a charging or discharging operating mode.

[0024] The power conversion control circuit system includes an AC side control circuit, a waveform observation circuit, a forward frequency modulation control circuit, a reverse frequency modulation control circuit, and a forward and reverse selection and judgment circuit;

[0025] The AC side control circuit is used to manage the switching state of the inverter to adjust the current and voltage, the waveform observation circuit is used to monitor the voltage, current and other parameters of each key point, the forward frequency modulation control circuit is used to control the frequency and direction of the CLLC resonant cavity circuit charging from the AC power grid to the DC power grid, and the reverse frequency modulation control circuit is used to control the frequency and direction of the CLLC resonant cavity circuit discharging from the DC power grid to the AC power grid.

[0026] The DC power grid is 360V DC power, and the AC power grid is 380V AC power.

[0027] A testing method for a V2G-based microgrid architecture on an ocean floating island, the testing method comprising the following steps:

[0028] A microgrid architecture test model is constructed, wherein the microgrid architecture test model includes an impedance matching circuit, wherein the impedance matching circuit includes a source and a load connected in series, and an expression of a current I of the impedance matching circuit is:

[0029]

[0030] The power P on the load of the impedance matching circuit L The expression is:

[0031]

[0032] In the above formula, V S is the source voltage, Z S is the source impedance, Z L is the load impedance, I is the current in the circuit;

[0033] To find the maximum power transfer condition, L Z L Take the derivative and set it to zero:

[0034]

[0035] Using the derivative rule of the quotient:

[0036]

[0037] Simplifying, we get:

[0038]

[0039] From the above formula, it can be concluded that when the load impedance Z L Equal to the source impedance Z S When the load receives the power P L Maximum, that is:

[0040]

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. In the V2G-based microgrid framework on a floating island in the ocean, different from the traditional power grid, which is mainly based on AC power grid wiring, two power supply systems, AC power grid and DC power grid, are designed. Due to the high transportation cost of AC generator fuel, the main power supply equipment on the floating island is a distributed power supply. As for electricity consumption, due to the limited layout area of ​​the floating island's power grid, the energy loss of DC power grid power supply is less than that of AC power grid power supply. Therefore, AC and DC power grids can be laid out according to demand. For the charging settings of cars and ships, DC power supply can be directly used without the DC-AC-DC energy conversion process, which is more stable and effectively improves energy utilization. Further, in order to cope with the power generation characteristics of wind power / photovoltaic power and improve the stability of the microgrid, a three-level energy stabilization system is adopted, which is mainly based on battery energy storage stations, supplemented by DC hydrogen production systems and fuel cells, and energy storage batteries of transportation vehicles as backup, effectively improving the stability and reliability of the microgrid.

[0043] 2. In a V2G-based microgrid architecture on an ocean floating island of the present invention, the AC system and the DC system are connected through an AC / DC conversion management system to realize forward charging and reverse power transmission of the DC system, that is, to realize intelligent charging and discharging of various devices on the ocean floating island, so that the battery of the equipment is used as distributed energy storage, and through the coordinated work of multiple modules such as inverter and power correction, AC side control, waveform observation, resonant conversion and frequency control, bidirectional power transmission between the battery and the power grid on the ocean floating island is realized, so as to achieve the effect of balancing the power grid load, optimizing the efficiency of power use, and improving the utilization rate of renewable energy. Therefore, this design can effectively reduce the volatility of microgrid operation through bidirectional power transmission between the battery and the power grid.

[0044] 2. In the V2G-based microgrid architecture on a floating island in the ocean, the DC system also includes a fuel cell and a fuel cell control system. The fuel cell and the fuel cell control system are used to convert excess electricity into chemical energy for storage and release electricity when the microgrid is short of electricity. By integrating multiple energy sources, loads and energy storage on the floating island, flexible switching between different forms of electricity is achieved, thereby improving the stability of the microgrid operation. Therefore, this design can achieve two-way conversion between chemical energy and electrical energy through fuel cells and fuel cell control systems, effectively improving the stability of the microgrid operation.

[0045] 3. In the test method of a V2-based microgrid architecture on an ocean floating island of the present invention, based on the disturbance observation method, the impedance matching and MPPT control methods are used to verify the impedance matching characteristics and high power output capabilities of photovoltaic power generation and microgrids on ocean floating islands. By taking the system impedance matching performance as an observation index and applying a disturbance signal to observe the system response changes, the system impedance matching degree is evaluated and its matching characteristics are confirmed. Therefore, this design can verify the reliability of the microgrid system through the disturbance observation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 2 is a microgrid architecture diagram of the present invention.

[0047] Figure 2 yes Figure 1 Circuit diagram of the AC-DC conversion management system.

[0048] Figure 3 yes Figure 2 Main circuit diagram of the AC-DC conversion management system.

[0049] Figure 4 yes Figure 2 AC side control circuit diagram of the AC-DC conversion management system.

[0050] Figure 5 yes Figure 2 Circuit diagram of the waveform observation circuit of the AC-DC conversion management system.

[0051] Figure 6 yes Figure 2 Circuit diagram of the forward frequency modulation control circuit and the reverse frequency modulation control circuit of the AC-DC conversion management system.

[0052] Figure 7 yes Figure 2 Circuit diagram of the forward and reverse selection and judgment circuit of the AC-DC conversion management system.

[0053] Figure 8 It is a circuit diagram of voltage control and switch control in the AC side control of the present invention.

[0054] Fig. 9 It is a phase synchronization circuit diagram of a phase-locked loop in the AC side control of the present invention.

[0055] Fig.10 It is the forward and reverse selection and judgment control strategy diagram of the present invention.

[0056] Fig.11 This is a diagram of the forward conversion bus voltage of the present invention.

[0057] Fig.12 It is the forward conversion PFC power correction diagram of the present invention.

[0058] Fig.13 It is the forward conversion output voltage diagram of the present invention.

[0059] Fig.14 It is the forward conversion resonant frequency diagram of the present invention.

[0060] Fig.15 It is a diagram of the reverse conversion bus voltage of the present invention.

[0061] Fig.16 It is the reverse transformation PFC correction diagram of the present invention.

[0062] Fig.17 It is the reverse conversion output voltage diagram of the present invention.

[0063] Fig.18 It is the resonant frequency diagram during reverse transformation of the present invention.

[0064] Fig.19 It is the impedance matching principle diagram of the disturbance test of the present invention.

[0065] Fig. 20 It is a diagram of an impedance matching verification module for the disturbance test of the present invention.

[0066] Fig.21 This is a diagram showing the maximum power achieved when impedance matching is performed in the present invention.

[0067] Fig. 22 It is a diagram showing the change of source voltage and output power when the load of the present invention changes. DETAILED DESCRIPTION

[0068] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0069] Embodiment 1:

[0070] See also Figures 1 to 7 , a V2G-based microgrid architecture on an ocean floating island, including: an AC side system, a DC side system and an AC / DC conversion management system;

[0071] The DC side system includes a battery energy storage system connected to the DC power grid, a wind power / photovoltaic power generation system, a fuel cell power generation system and a DC hydrogen production system;

[0072] The battery energy storage system includes: a battery energy storage station inherent in the power grid system and an energy storage battery of a vehicle connected to a DC charging station; the battery energy storage system is used to stabilize the energy supply of the power grid by using the battery energy storage station to "cut peaks and fill valleys", and the battery energy storage system is used to charge the energy storage battery of the vehicle using the DC charging station, and when the set conditions are met, the energy storage battery of the vehicle can be used to reversely supply power to the power grid;

[0073] The wind power / photovoltaic power generation system is an offshore floating island wind power / photovoltaic power generation array;

[0074] The DC hydrogen production system is used to electrolyze water to produce hydrogen for storage when the wind power / photovoltaic power generation system has surplus power generation;

[0075] The fuel cell power generation system is used to generate electricity using hydrogen when there is a shortage of electricity;

[0076] The AC / DC conversion management system is used for mutual conversion of electric energy between the AC side system and the DC side system.

[0077] The energy storage batteries of the transportation means include energy storage batteries on electric cars, ships, diving equipment and energy storage batteries on other power source ships.

[0078] The AC system includes an AC generator, a reactive load device, an active load device and a power quality monitoring device. The reactive load device and the active load device are connected in series with the power quality monitoring device and then connected to the AC / DC conversion management system;

[0079] The reactive load device is used to compensate reactive power, the active load device is used to consume active power, and the power quality monitoring device is used to monitor and adjust the active and reactive power balance in the AC power grid.

[0080] The direct current hydrogen production system includes an electrolyzer and a gas storage device. The electrolyzer is used to use excess electricity to electrolyze water to produce hydrogen and oxygen, and the gas storage device is used to store hydrogen and oxygen respectively.

[0081] The AC / DC conversion management system includes a power conversion main circuit and a power conversion control circuit.

[0082] The power conversion main circuit comprises: an inverter and power factor correction circuit and a CLLC resonant cavity circuit, wherein the AC side of the inverter and power factor correction circuit is connected to the AC grid, the DC side of the inverter and power factor correction circuit is connected to a 400V DC bus, one side of the CLLC resonant cavity circuit is connected to the 400V DC bus, and the other side of the CLLC resonant cavity circuit is connected to the DC grid;

[0083] The CLLC resonant cavity module is used to optimize energy transmission efficiency by adjusting the resonant frequency in a charging or discharging operating mode.

[0084] The power conversion control circuit system includes an AC side control circuit, a waveform observation circuit, a forward frequency modulation control circuit, a reverse frequency modulation control circuit, and a forward and reverse selection and judgment circuit;

[0085] The AC side control circuit is used to manage the switching state of the inverter to adjust the current and voltage, the waveform observation circuit is used to monitor the voltage, current and other parameters of each key point, the forward frequency modulation control circuit is used to control the frequency and direction of the CLLC resonant cavity circuit charging from the AC power grid to the DC power grid, and the reverse frequency modulation control circuit is used to control the frequency and direction of the CLLC resonant cavity circuit discharging from the DC power grid to the AC power grid.

[0086] The DC power grid is 360V DC power, and the AC power grid is 380V AC power.

[0087] Embodiment 2:

[0088] The constructed microgrid was simulated and run to evaluate various output indicators. The results are as follows:

[0089] Forward transformation:

[0090] See also Fig.11 , the bus voltage fluctuates to a certain extent at 400V. This is because this circuit is a two-stage circuit. The response speeds of the front stage and the rear stage are different, so the front stage will have disturbances and need to be constantly adjusted;

[0091] Voltage range: As can be seen from the image, the voltage fluctuation range is around 400V, and the specific fluctuation range is between 390V and 410V, which shows that the voltage remains at a relatively high stable level, but there are some small fluctuations;

[0092] Time axis: The time axis extends from 0 to about 1.2 seconds. It can be seen that the voltage fluctuation frequency is relatively high during this period;

[0093] Voltage fluctuations: The voltage shows frequent, high-frequency, small fluctuations between 0 seconds and 0.2 seconds. This fluctuation may be caused by the control system response in the simulation model;

[0094] Overall trend: As can be seen from the figure, the voltage is basically maintained at a high level, with no obvious downward or upward trend, which shows that the system is relatively stable;

[0095] From this, we can conclude that the bus voltage fluctuates slightly and remains around 400V;

[0096] See also Fig.12 , the image shows two different waveforms: a high-frequency, large-amplitude waveform, and a low-frequency, small-amplitude waveform. The high-frequency waveform represents the change in the grid-side voltage, with a higher fluctuation frequency and a larger amplitude, and the low-frequency waveform represents the grid-side current, showing a smaller fluctuation amplitude and a lower frequency. This is usually the goal of a PFC circuit, that is, to convert the input high-frequency, large-amplitude signal into a more stable output signal;

[0097] As can be seen from the figure, at the beginning of the time axis, the low-frequency waveform has some large fluctuations, but soon stabilizes. This shows that the PFC circuit makes adjustments at the beginning and gradually stabilizes the output within a smaller fluctuation range. As time goes by, the frequency and amplitude of the blue waveform gradually decrease, showing the good regulation performance of the system;

[0098] The image shows that the PFC circuit effectively corrects the input high-frequency, large-amplitude signal into a relatively stable output signal. This helps to improve the power factor of the system, reduce harmonic distortion, and improve the quality of power. From this we can conclude that:

[0099] 1. The PFC circuit effectively stabilizes the output signal, reduces the fluctuation amplitude, and shows a good power factor correction effect;

[0100] 2. The system has large fluctuations in the early stage of simulation, but quickly stabilizes, indicating that the regulation and correction performance of the PFC circuit is good;

[0101] 3. PFC power correction is achieved through phase locking. From the waveform, we can see that the grid-side voltage and current are in phase, and the power factor is about 1.

[0102] See also Fig.13 , the image shows that the voltage fluctuation range is about 350V to 370V. This shows that the output voltage is relatively stable, with only small fluctuations, and the time axis is from 0 seconds to 0.3 seconds. It can be seen that during the entire time period, the voltage fluctuation frequency is high, but the amplitude is small, and the output voltage waveform shows a small periodic fluctuation, which may be caused by the harmonics in the system or the adjustment of the control system. The fluctuation amplitude is small, indicating that the system output voltage is relatively stable and the control effect is good;

[0103] It can be seen from the figure that the output voltage basically remains at a stable level, with no obvious upward or downward trend, which shows the stability of the system in a short period of time. From this, we can conclude that:

[0104] The output voltage is stable at around 360V, showing good stability. The overall trend shows that the voltage remains stable without significant changes, indicating that the system's output voltage control effect is good;

[0105] See also Fig.14 , we can conclude that:

[0106] Peak frequency: When the system starts or switches to forward transmission mode, the switching frequency rises rapidly to around 260Hz;

[0107] Transition stage: Between 0 seconds and 0.05 seconds, the switching frequency drops rapidly, indicating that the system undergoes transient adjustments during startup;

[0108] Stable frequency: After 0.1 seconds, the switching frequency stabilizes at around 140Hz, and the system enters a stable operating state;

[0109] Inverse transformation:

[0110] See also Fig.15 ,Similar to the forward transformation, it can be concluded that the bus voltage fluctuates slightly and remains at around 400V;

[0111] See also Fig.16 , similar to the forward transformation, we can conclude that:

[0112] 1. The PFC circuit effectively stabilizes the output signal, reduces the fluctuation amplitude, and shows a good power factor correction effect;

[0113] 2. The system has large fluctuations in the early stage of simulation, but quickly stabilizes, indicating that the regulation and correction performance of the PFC circuit is good;

[0114] 3. PFC power correction is achieved through phase locking. From the waveform, we can see that the voltage and current on the grid side are reversed, which means that the energy DC side → AC side, and the power factor is about 1.

[0115] See also Fig.17 , similar to the forward conversion, it can be concluded that the output voltage fluctuates less and is stable at 360V;

[0116] See also Fig.18 ,Initial state: At the beginning of the time axis (0 seconds), the reverse switching frequency rises rapidly and reaches a peak value of about 260Hz; this may be due to the instantaneous high frequency generated when the system starts or switches to the reverse charging mode;

[0117] 2. Transient response: Between 0 seconds and 0.1 seconds, the frequency drops rapidly. The rapid drop during this period may be a transient phenomenon during the system response startup process, and gradually stabilizes;

[0118] 3. Steady state: Starting from about 0.1 seconds, the frequency drops to a stable value of about 140Hz and remains unchanged throughout the simulation time (0.1 seconds to 3 seconds). This shows that the system enters a stable operation state after the initial adjustment, and the switching frequency stabilizes at about 140Hz;

[0119] 4. Timeline: The timeline extends from 0 seconds to 3 seconds. The image shows the change of switching frequency during the entire simulation process, from the startup transient to the steady state;

[0120] From this we can conclude that:

[0121] 1. Peak frequency: When the system starts or switches to reverse charging mode, the switching frequency rises rapidly to around 260Hz.

[0122] 2. Transition stage: Between 0 seconds and 0.1 seconds, the switching frequency drops rapidly, indicating that the system undergoes transient adjustments during startup.

[0123] 3. Stable frequency: After 0.1 second, the switching frequency stabilizes at around 140Hz, and the system enters a stable operating state.

[0124] Embodiment 3:

[0125] See also Fig.19 , a testing method for a V2G-based microgrid architecture on an ocean floating island, the testing method comprising the following steps:

[0126] A microgrid architecture test model is constructed, wherein the microgrid architecture test model includes an impedance matching circuit, wherein the impedance matching circuit includes a source and a load connected in series, and an expression of a current I of the impedance matching circuit is:

[0127]

[0128] The power P on the load of the impedance matching circuit L The expression is:

[0129]

[0130] In the above formula, V S is the source voltage, Z S is the source impedance, Z L is the load impedance, I is the current in the circuit;

[0131] To find the maximum power transfer condition, L Z L Take the derivative and set it to zero:

[0132]

[0133] Using the derivative rule of the quotient:

[0134]

[0135] Simplifying, we get:

[0136]

[0137] From the above formula, it can be concluded that when the load impedance Z L Equal to the source impedance Z S When the load receives the power P L Maximum, that is:

[0138]

[0139] See also Fig. 20 ,System 1 directly connects the load to the power source and changes the load through a voltage ramp, so the load is affected by the voltage ramp. System 2 has a buck / boost power converter between the source and the load and uses a maximum power point tracking algorithm based on the disturbance observer method to supply power.

[0140] See also Fig.21 , when the load voltage matches the source voltage, that is, when the impedance is matched, the maximum power is output, that is, at 100V, the maximum power is 100W.

[0141] See also Fig. 22 , even though the load voltage is changing, the source voltage and output power remain at 100V and 100W respectively, which further illustrates that the MPPT algorithm presents a matched impedance to the source even when the load conditions change.

[0142] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the contents disclosed by the present invention should be included in the protection scope recorded in the claims.

Claims

1. A V2G-based microgrid architecture on an ocean floating island, characterized by: include: AC side system, DC side system and AC / DC conversion management system; The DC side system includes a battery energy storage system connected to the DC power grid, a wind power / photovoltaic power generation system, a fuel cell power generation system and a DC hydrogen production system; The battery energy storage system includes: a battery energy storage station inherent to the power grid system and an energy storage battery of a vehicle connected to a DC charging station; The battery energy storage system is used to stabilize the energy supply of the power grid by "peak shaving and valley filling" using the battery energy storage station. The battery energy storage system is used to charge the energy storage battery of the vehicle using the DC charging station. When the set conditions are met, the energy storage battery of the vehicle can be used to supply power to the power grid in reverse; The wind power / photovoltaic power generation system is an offshore floating island wind power / photovoltaic power generation array; The DC hydrogen production system is used to electrolyze water to produce hydrogen for storage when the wind power / photovoltaic power generation system has surplus power generation; The fuel cell power generation system is used to generate electricity using hydrogen when there is a shortage of electricity; The AC / DC conversion management system is used for mutual conversion of electric energy between the AC side system and the DC side system.

2. The V2G-based microgrid architecture on an ocean floating island according to claim 1, characterized in that: The energy storage batteries of the transportation vehicles include energy storage batteries on electric cars, ships, diving equipment and energy storage batteries on other power source ships.

3. The V2G-based microgrid architecture on an ocean floating island according to claim 1 is characterized in that: The AC system includes an AC generator, a reactive load device, an active load device and a power quality monitoring device. The reactive load device and the active load device are connected in series with the power quality monitoring device and then connected to the AC / DC conversion management system; The reactive load device is used to compensate reactive power, the active load device is used to consume active power, and the power quality monitoring device is used to monitor and adjust the active and reactive power balance in the AC power grid.

4. The V2G-based microgrid architecture on an ocean floating island according to claim 1 is characterized in that: The direct current hydrogen production system includes an electrolyzer and a gas storage device. The electrolyzer is used to use excess electricity to electrolyze water to produce hydrogen and oxygen, and the gas storage device is used to store hydrogen and oxygen respectively.

5. A V2G-based microgrid structure on an ocean floating island according to claim 1, 2, 3 or 4, characterized in that: The AC / DC conversion management system includes a power conversion main circuit and a power conversion control circuit.

6. The V2G-based microgrid structure on an ocean floating island according to claim 5 is characterized in that: The power conversion main circuit comprises: an inverter and power factor correction circuit and a CLLC resonant cavity circuit, wherein the AC side of the inverter and power factor correction circuit is connected to the AC grid, the DC side of the inverter and power factor correction circuit is connected to a 400V DC bus, one side of the CLLC resonant cavity circuit is connected to the 400V DC bus, and the other side of the CLLC resonant cavity circuit is connected to the DC grid; The CLLC resonant cavity module is used to optimize energy transmission efficiency by adjusting the resonant frequency in a charging or discharging operating mode.

7. The V2G-based microgrid structure on an ocean floating island according to claim 6 is characterized in that: The power conversion control circuit system includes an AC side control circuit, a waveform observation circuit, a forward frequency modulation control circuit, a reverse frequency modulation control circuit, and a forward and reverse selection and judgment circuit; The AC side control circuit is used to manage the switching state of the inverter to adjust the current and voltage, the waveform observation circuit is used to monitor the voltage, current and other parameters of each key point, the forward frequency modulation control circuit is used to control the frequency and direction of the CLLC resonant cavity circuit charging from the AC power grid to the DC power grid, and the reverse frequency modulation control circuit is used to control the frequency and direction of the CLLC resonant cavity circuit discharging from the DC power grid to the AC power grid.

8. The V2G-based microgrid architecture on an ocean floating island according to claim 7, characterized in that: The DC power grid is 360V DC power, and the AC power grid is 380V AC power.

9. A method for testing a V2G-based microgrid architecture on an ocean floating island according to any one of claims 1 to 8, characterized in that: The test method comprises the following steps: A microgrid architecture test model is constructed, wherein the microgrid architecture test model includes an impedance matching circuit, wherein the impedance matching circuit includes a source and a load connected in series, and an expression of a current I of the impedance matching circuit is: The power P on the load of the impedance matching circuit L The expression is: In the above formula, V S is the source voltage, Z S is the source impedance, Z L is the load impedance, I is the current in the circuit; To find the maximum power transfer condition, L Z L Take the derivative and set it to zero: Using the derivative rule of the quotient: Simplifying, we get: From the above formula, it can be concluded that when the load impedance Z L Equal to the source impedance Z S When the load receives the power P L Maximum, that is:

Images