A photovoltaic, diesel and AC / DC microgrid system

Abstract

The present application relates to the technical field of smart grids, and in particular to a photovoltaic-storage-diesel-AC-DC microgrid system, which includes a photovoltaic module, a diesel generator module, an energy storage module, an energy storage converter PCS, a DCDC converter, an STS smart switching cabinet and an energy management module. The photovoltaic module and the energy storage module are electrically connected to the STS smart switching cabinet through the energy storage converter PCS, respectively, the diesel generator module is electrically connected to the STS smart switching cabinet, the STS smart switching cabinet is connected to the user-side load, the diesel generator module, the energy storage module, the energy storage converter PCS, the DCDC converter and the STS smart switching cabinet are all communicatively connected to the energy management module, and the energy management module controls the photovoltaic module, the diesel generator module, the energy storage module and the power grid to supply power to the user-side load. The present application has the advantages of further improving the energy-saving potential of the system through a specific system structure and an energy management module control method.

Description

Technical Field

[0001] The present application relates to the technical field of smart grids, and in particular to a photovoltaic, energy-storage, diesel, AC and DC microgrid system. Background Art

[0002] With the growth of global energy demand and increasingly severe environmental problems, the development and utilization of renewable energy has become a global consensus. As a composite energy system integrating photovoltaic power generation, energy storage and diesel power generation, the photovoltaic-storage-diesel system has received extensive attention and application due to its stable, reliable, clean and environmentally friendly characteristics. The system absorbs solar energy into electrical energy through photovoltaic panels, and uses energy storage modules (such as batteries) to store electrical energy for use at night or in rainy weather. At the same time, it is equipped with a diesel generator as a backup power source to ensure energy supply when photovoltaic power generation is insufficient or system maintenance is required. It has a high self-sufficiency rate and reduces dependence on external power supply.

[0003] In the solar-energy-storage-diesel system, the charge and discharge control of the energy storage module is the key link to achieve cost savings and optimize system efficiency. Existing solar-energy-storage-diesel systems generally adopt a peak-shaving and valley-filling operation mode, that is, the battery is charged during the low-valley electricity price period, and the battery stored energy is preferentially used to supply the user-side load during the peak electricity price period, thereby reducing electricity bills. However, although this operation mode reduces the electricity cost to a certain extent, it does not give full play to the energy-saving potential of the solar-energy-storage-diesel system. Summary of the invention

[0004] In order to further improve the energy-saving potential, the present application provides a photovoltaic, energy-storage, diesel, AC and DC microgrid system.

[0005] The present application provides a photovoltaic-storage-diesel AC / DC microgrid system, which adopts the following technical solutions:

[0006] A photovoltaic-storage-diesel AC / DC microgrid system, comprising a photovoltaic module, a diesel generator module, an energy storage module, an energy storage converter PCS, a DCDC converter, an STS intelligent switching cabinet and an energy management module, wherein the photovoltaic module and the energy storage module are electrically connected to the STS intelligent switching cabinet through the energy storage converter PCS respectively, the diesel generator module is electrically connected to the STS intelligent switching cabinet, the STS intelligent switching cabinet is connected to the user-side load, the diesel generator module, the energy storage module, the energy storage converter PCS, the DCDC converter and the STS intelligent switching cabinet are all communicatively connected to the energy management module, and the energy management module controls the photovoltaic module, the diesel generator module, the energy storage module and the power grid to supply power to the user-side load;

[0007] The specific control method of the energy management module includes:

[0008] Obtain the photovoltaic power of the photovoltaic module and the battery SOC of the energy storage module;

[0009] When the battery SOC is lower than the lower limit and the photovoltaic power minus the load power < a, the diesel generator module is controlled to start; when the battery SOC is higher than the upper limit and the photovoltaic power minus the load power > b, the diesel generator module is controlled to shut down; wherein, when the diesel generator module is started, the grid-connected mode is started, and when the diesel generator module is shut down, the off-grid mode is started;

[0010] In the grid-connected mode, when the diesel generator power + photovoltaic power of the diesel generator module > load power, the diesel generator module is controlled to charge the energy storage module;

[0011] In the grid-connected mode, when the diesel power + photovoltaic power < load power, it is determined whether the electricity price is at peak or valley time;

[0012] If it is at peak time, based on the battery SOC condition, control the energy storage module and / or the power grid to supply power to the user-side load;

[0013] If it is in the valley period, historical photovoltaic power data and meteorological data are obtained, and the preset model is used to predict the time T1 when the diesel power + photovoltaic power - load power > c, and based on T1 and the battery SOC, the control strategy for charging or discharging the energy storage module is output.

[0014] In one embodiment, the step of controlling the energy storage module and / or the power grid to supply power to the user-side load based on the battery SOC condition specifically includes:

[0015] When the battery SOC is higher than the upper limit, if the load power is greater than the maximum power of the PCS, the energy storage module and the power grid jointly supply power to the load side; if the load power is less than the maximum power of the PCS, the energy storage module alone supplies power to the load side;

[0016] When the battery SOC is higher than a lower limit and lower than an upper limit, the energy storage module and the power grid jointly supply power to the load side;

[0017] When the battery SOC is lower than the lower limit, the power grid supplies power to the load side alone.

[0018] In one embodiment, the step of outputting the control strategy for charging or discharging the energy storage module based on T1 and the battery SOC specifically includes:

[0019] If T1 is in the valley, when the diesel power + photovoltaic power - load power > d, the grid power supply is stopped;

[0020] If T1 is at the peak time, compare P1, P2 and P3, and take the larger value to calculate the power supply time T2 of the energy storage module under the current battery SOC, and calculate the power supply time T3, where T3=T1-T2, P1 is the current load power, P2 is the maximum historical average load power in the historical valley time, and P3 is the maximum historical average load power in the historical peak time;

[0021] Based on T2, T3 and the battery SOC, the charging and discharging conditions of the energy storage module are determined.

[0022] In one embodiment, the step of determining the charging and discharging conditions of the energy storage module based on T2, T3 and the battery SOC specifically includes:

[0023] If the battery SOC is higher than the upper limit, the energy storage module is powered after T3;

[0024] If the battery SOC is lower than the upper limit but higher than the lower limit, determine whether it is in the valley period after T3. If so, the energy storage module is powered after T3. If not or the battery SOC is lower than the lower limit, calculate the time T4 required to fully charge the energy storage module and the power supply time T5 of the energy storage module when fully charged, and determine the charging time and power supply time point of the energy storage module.

[0025] In one embodiment, the step of determining the charging time and power supply time point of the energy storage module specifically includes:

[0026] Calculate the available power supply time T6, T6=T1-T5;

[0027] If T4>T6, and the period after T4 is valley time, the energy storage module is charged, and the energy storage module is started to supply power during peak time;

[0028] If T4>T6, and the period after T4 is peak, the battery SOC after the energy storage module is charged is calculated based on the remaining time during the valley period. Based on the calculated battery SOC and P3, the remaining power supply time T7 and the remaining power supply time T8 are calculated. If the period after T8 is peak, the energy storage module is started to supply power after T8; if the period after T8 is valley, the energy storage module is started to supply power during the peak period.

[0029] If T4<T6, and the period after T6 is a valley period, the energy storage module is charged, and then the energy storage module is charged;

[0030] If T4<T6, and the period after T6 is a peak period, determine whether the period after T4 is a valley period. If so, charge the energy storage module and start the energy storage module to supply power after T6. If not, calculate the battery SOC of the energy storage module after charging based on the remaining time during the valley period, calculate the remaining power supply time T7 and the remaining power supply time T8 based on the calculated battery SOC and P3, and start the energy storage module to supply power after T8.

[0031] In one embodiment, after the step of obtaining historical photovoltaic power data and meteorological data, predicting the time T1 when diesel power + photovoltaic power - load power > c through a preset model, and outputting the control strategy for charging or discharging the energy storage module based on T1 and the battery SOC, the step further includes:

[0032] Set verification time based on T1;

[0033] After the verification time, the preset model is used to predict the time T2 when the diesel power + photovoltaic power - load power > c;

[0034] Compare T1 and T2, and determine based on the comparison result whether to re-output the control strategy for charging or discharging the energy storage module based on T2 and the battery SOC condition.

[0035] In one embodiment: the verification time is N*T1, where N is less than 1;

[0036] The step of comparing T1 and T2 is specifically to determine whether T2+N*T1 is greater than T1, and if so, re-output the control strategy for charging or discharging the energy storage module.

[0037] In one of the embodiments: if T1 is greater than 24h, the power grid is kept supplying power to the load side alone and the energy storage module is charged synchronously.

[0038] In one of the embodiments: if T1 is greater than 24h, the power grid is kept supplying power to the load side alone and the energy storage module is charged synchronously. If the electricity price is at peak or the battery SOC is higher than the upper limit, the energy storage module is stopped from being charged; and the time T1 is re-predicted after each preset time.

[0039] In one of the embodiments: 0KW<c<a<b, 0KW<d<a<b.

[0040] In summary, this application has the following beneficial effects:

[0041] By adopting a specific system structure and using a prediction model to predict the future photovoltaic power situation, the charging and discharging strategy of the energy storage module is controlled by the prediction results to achieve refined control, reduce the number of charging and discharging times of the energy storage module, and reduce the energy loss of the energy storage module during the charging and discharging process. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a structural diagram of a photovoltaic, energy-storage, diesel, AC and DC microgrid system in an embodiment;

[0043] Figure 2 It is a control logic diagram of the STS intelligent switching cabinet in the embodiment.

[0044] In the figure, 100, photovoltaic module; 200, diesel generator module; 300, energy storage module; 400, energy storage converter PCS; 500, DCDC converter; 600, STS intelligent switching cabinet; 700, energy management module. DETAILED DESCRIPTION

[0045] The present application is further described in detail below in conjunction with the accompanying drawings.

[0046] In the description of the present application, it should be understood that the terms "up", "down", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0047] A photovoltaic, diesel and AC / DC microgrid system, such as Figure 1 As shown, it includes a photovoltaic module 100, a diesel generator module 200, an energy storage module 300, an energy storage converter PCS400, a DCDC converter 500, an STS intelligent switching cabinet 600 and an energy management module 700.

[0048] The photovoltaic module 100 and the energy storage module 300 are electrically connected to the STS intelligent switching cabinet 600 through the energy storage converter PCS400, respectively. The photovoltaic module 100 and the energy storage module 300 are both provided with two groups to form two sets of DC systems. The capacity of the two groups of photovoltaic modules 100 is 800KWp. The energy storage module 300 adopts a 645.12kWh battery system and is connected to the DC bus side through two sets of 400kwDCDC. The energy storage converter PCS400 is equipped with two sets of 500kW isolation transformer systems, and the STS intelligent switching cabinet 600 is equipped with an 800kW switching switch. The STS intelligent switching cabinet 600 is used to achieve on-grid and off-grid switching, and the switching time is required to be within 20ms.

[0049] The diesel generator module 200 is also electrically connected to the STS intelligent switching cabinet 600, which is connected to the user-side load. The diesel generator module 200, the energy storage module 300, the energy storage converter PCS400, the DCDC converter 500 and the STS intelligent switching cabinet 600 are all connected to the energy management module 700 for communication, and the energy management module 700 controls the photovoltaic module 100, the diesel generator module 200, the energy storage module 300 and the power grid to supply power to the user-side load. In this embodiment, the user-side load is 600KVA.

[0050] When there is sunlight during the day, the photovoltaic module 100 generates electricity to ensure the load power consumption, and the excess is used to charge the energy storage module 300. After the energy storage module 300 is fully charged, the photovoltaic power generation limit protection is performed. The diesel generator module 200 is used as a supplementary energy source. At night, the energy storage module 300 mainly supplies power to the load. When the energy storage module 300 is insufficient, the diesel generator module 200 supplements the power supply.

[0051] Among them, the STS intelligent switching cabinet 600 consists of four parts: switching switch, high-precision detection, logic control, and external communication. It can automatically complete the grid-connected and off-grid switching and grid-connected synchronization functions. The active switching grid-connected and off-grid time is 0ms, and the passive switching time is within 20ms.

[0052] like Figure 2 As shown, the control logic of the STS intelligent switching cabinet 600 is specifically as follows:

[0053] 1) Passive switching:

[0054] Typical switching: The sampling board samples the grid-side information in real time and then transmits it to the control board. When the grid-side voltage drops, the control board detects half a cycle and determines that the grid is out of power. At this time, it controls the fast switch to disconnect and sends the off-grid switching instruction to the PCS. The whole process takes less than 20ms.

[0055] 2) Active switching:

[0056] The monitoring sends an off-grid command, and the PCS switches to off-grid operation after receiving the command, and the STS disconnects the fast switch. This process is a seamless switch.

[0057] 3) Synchronous grid connection:

[0058] The monitoring sends the grid connection instruction. After receiving it, STS starts to detect the grid voltage and controls the PCS output to change the phase and amplitude until it matches the grid. The grid connection is successful. This process is a seamless switching.

[0059] The specific control method of the energy management module 700 includes:

[0060] S100 , obtaining the photovoltaic power of the photovoltaic module 100 and the battery SOC of the energy storage module 300 .

[0061] The battery SOC indicates the ratio of the remaining power of the battery to its rated capacity, usually expressed as a percentage; the photovoltaic power and the battery SOC are acquired in real time.

[0062] S200: Output diesel generator control information based on the battery SOC, photovoltaic power and load power.

[0063] In the above steps, the diesel generator control information includes a start signal and a shutdown signal. When the battery SOC is lower than the lower limit and the photovoltaic power-load power is less than a, the diesel generator control information is output to control the diesel generator module 200 to start; when the battery SOC is higher than the upper limit and the photovoltaic power-load power is greater than b, the diesel generator control information is output to control the diesel generator module 200 to shut down.

[0064] When the diesel generator module 200 is started, the grid-connected mode is started, and when the diesel generator module 200 is shut down, the off-grid mode is started, and a is less than b.

[0065] S300 , in the grid-connected mode, when the diesel generator power + the photovoltaic power of the diesel generator module 200 is greater than the load power, the diesel generator module 200 is controlled to charge the energy storage module 300 .

[0066] In the above steps, when the diesel power + photovoltaic power of the diesel generator module 200 is greater than the load power, it means that the output power of the diesel generator module 200 is sufficient for the load, that is, the power generation is surplus. At this time, the surplus power can be used to charge the energy storage module 300 to store the electric energy.

[0067] S400, in grid-connected mode, when diesel power + photovoltaic power < load power, determine whether the electricity price is at peak or valley time.

[0068] In the above steps, when the diesel power + photovoltaic power of the diesel generator module 200 is less than the load power, it means that the output power of the diesel generator module 200 is insufficient to meet the load usage, so it is necessary to compensate by power supply from the grid. At this time, it is determined whether the electricity price is at peak or valley time to perform peak shaving and valley filling operations.

[0069] S500: If it is peak time, control the energy storage module 300 and / or the grid to supply power to the user-side load based on the battery SOC.

[0070] In the above steps, the peak electricity price is high, and the energy storage module 300 is used to supply power first. Therefore, by judging the battery SOC, it is determined whether to intervene in the power supply through the energy storage module 300, thereby saving electricity costs.

[0071] Specifically, in one embodiment, the step of controlling the energy storage module 300 and / or the power grid to supply power to the user-side load based on the battery SOC condition specifically includes:

[0072] S510, when the battery SOC is higher than the upper limit, if the load power is greater than the PCS maximum power, the energy storage module 300 and the power grid jointly supply power to the load side; if the load power is less than the PCS maximum power, the energy storage module 300 alone supplies power to the load side.

[0073] In this step, if the load power is less than the PCS maximum power, it means that the energy storage module 300 can meet the load supply. Therefore, power can be supplied only through the energy storage module 300. Otherwise, it means that the energy storage module 300 cannot meet the load supply.

[0074] S520: When the battery SOC is higher than the lower limit and lower than the upper limit, the energy storage module 300 and the power grid jointly supply power to the load side.

[0075] S530: When the battery SOC is lower than the lower limit, the grid supplies power to the load side alone.

[0076] S600: If it is valley time, obtain historical photovoltaic power data and meteorological data, and predict the time T1 when diesel power + photovoltaic power - load power > c through a preset model.

[0077] In the above steps, whether the energy storage module 300 needs to be charged, how long to charge, and when to discharge the energy storage module 300 are determined according to the predicted time T1 and the battery SOC. In addition, 0KW<c<a<b.

[0078] The above-mentioned meteorological data include solar radiation intensity, temperature, humidity, wind speed, air pressure, precipitation, etc. The preset model can be one or more combinations of LSSVM model, LSTM model, CNN_LSTM model, and XGBoost regression model.

[0079] It should be noted that, in order to avoid excessive deviation in the results due to the calculation time process, preferably, T1 is less than 24h.

[0080] In one embodiment, the following steps are also included:

[0081] S610: If T1 is greater than 24 hours, the grid is kept supplying power to the load side alone and charging the energy storage module 300 synchronously.

[0082] S620 . During the charging process of the energy storage module 300 in S610 , if the electricity price is at a peak or the battery SOC is higher than an upper limit, the charging of the energy storage module 300 is stopped.

[0083] S630, executing step S600 once after each preset time to re-predict time T1, wherein the preset time is less than or equal to 12 hours, usually set to 6 hours, and can also be set to 1 hour or even shorter to improve accuracy.

[0084] S700 , based on T1 and the battery SOC, output a control strategy for charging or discharging the energy storage module 300 .

[0085] Specifically, in one embodiment, based on T1 and the battery SOC, the steps of outputting the control strategy for charging or discharging the energy storage module 300 specifically include:

[0086] S710: If T1 is in the valley time and when diesel power + photovoltaic power - load power > d, stop the grid power supply, where 0KW < d < a < b.

[0087] In the above steps, d is greater than 0. Therefore, when diesel generator power + photovoltaic power - load power > d, it can be basically determined that the power generation power of the diesel generator module 200 and the photovoltaic module 100 can meet the load usage. Therefore, the grid power supply can be stopped.

[0088] S720 , if T1 is at the peak time, compare P1 , P2 and P3 , and take the larger value to calculate the power supply time T2 of the energy storage module 300 under the current battery SOC, and calculate the power supply time T3 .

[0089] In the above steps, T3 = T1-T2, P1 is the current load power, P2 is the maximum historical average load power in the historical valley time, and P3 is the maximum historical average load power in the historical peak time. Among them, P2 specifically refers to the average value of each valley time period, and P3 specifically refers to the average value of each peak time period.

[0090] S730 , based on T2 , T3 and the battery SOC, determine the charging and discharging status of the energy storage module 300 .

[0091] In another embodiment, based on T2, T3 and the battery SOC, the step of determining the charging and discharging conditions of the energy storage module 300 specifically includes:

[0092] S731 . If the battery SOC is higher than the upper limit, the energy storage module 300 supplies power after T3 .

[0093] In the above steps, when the battery SOC is higher than the upper limit, it indicates a fully charged state and no charging is required at this time. Therefore, power is supplied after T3, and the battery re-supply time can be guaranteed to be above T2 at this time, thereby ensuring that the energy storage module 300 can guarantee that the sum of the diesel power and the volt power is greater than the load power.

[0094] S732: If the battery SOC is lower than the upper limit but higher than the lower limit, determine whether it is in the valley period after T3.

[0095] S733: If yes, the energy storage module 300 is powered after T3.

[0096] S734, if not or the battery SOC is lower than the lower limit, calculate the time T4 required to fully charge the energy storage module 300 and the power supply time T5 of the energy storage module 300 when fully charged.

[0097] In the above steps, since the energy storage module 300 supplies power during peak hours, the power supply duration T5 of the energy storage module 300 when fully charged is calculated by the maximum historical average load power P3 during historical peak hours.

[0098] S735 , determining the charging time and power supply time point of the energy storage module 300 .

[0099] In the above steps, when the battery SOC is lower than the upper limit or higher than the lower limit, different control strategies need to be adopted for the electricity price situation after T3 with the current time as the initial point. If it is in the valley time after T3, it means that the sum of the diesel power and the volt power can be greater than the load power in the valley time. Therefore, it is necessary to charge the energy storage module 300, and power supply can be performed after T3. After T3, the energy storage module 300 can be charged by the excess power generated by the diesel module 200 and the photovoltaic module 100.

[0100] If T3 is at a peak time, or the battery SOC is lower than the lower limit, the energy storage module 300 needs to be charged during the valley time, and the charging time needs to be calculated, and the energy storage module 300 needs to be powered appropriately.

[0101] In another embodiment, the step of determining the charging time and the power supply time point of the energy storage module 300 specifically includes:

[0102] S7351. Calculate the available power supply time T6, where T6 = T1-T5.

[0103] S7352: If T4>T6 and the period after T4 is valley time, the energy storage module 300 is charged and the energy storage module 300 is started to supply power during peak time.

[0104] In the above steps, T4>T6 means that theoretically the power supply time is earlier than the charging time. Therefore, if the charging time T4 is during the off-peak period, the energy storage module 300 is fully charged first, and then the energy storage module 300 is started during the peak period to provide power with the lowest energy consumption.

[0105] S7353, if T4>T6, and the period after T4 is the peak period, then the battery SOC of the energy storage module 300 after charging is calculated based on the remaining time during the valley period, and the remaining power supply time T7 and the remaining power supply time T8 are calculated based on the calculated battery SOC and P3. If the period after T8 is the peak period, then the energy storage module 300 is started to supply power after T8; if the period after T8 is the valley period, then the energy storage module 300 is started to supply power during the peak period.

[0106] In the above steps, if T4>T6 and the time after T4 is the peak time, it means that the energy storage module 300 cannot be fully charged during the valley time. Therefore, it is necessary to calculate how much power can be charged to the energy storage module 300 in the remaining time during the valley time, and then calculate the remaining power supply time T7 based on the calculated battery SOC and P3, and then calculate the remaining power supply time T8 through T1-T7. After passing T8, whether it is the peak time or the valley time, the optimal power supply time of the energy storage module 300 is determined.

[0107] S7354: If T4<T6, and the time after T6 is valley time, the energy storage module 300 is charged. Then the energy storage module 300 is charged.

[0108] In the above steps, T4<T6 means that the theoretical power supply time is later than the charging time. Therefore, if the period after T6 is valley time, it means that charging can be completed in valley time, and when the power supply is started in peak time, the energy storage module 300 can continue until the sum of the diesel power and the volt power is greater than the load power. If the power supply is started too early, it will cause loss due to both charging and discharging in valley time.

[0109] S7355, if T4 is less than T6, and the period after T6 is a peak period, determine whether the period after T4 is a valley period, if so, charge the energy storage module 300, and start the energy storage module 300 to supply power after T6; if not, calculate the battery SOC of the energy storage module 300 after charging based on the remaining time during the valley period, calculate the remaining power supply time T7 and the remaining power supply time T8 based on the calculated battery SOC and P3, and start the energy storage module 300 to supply power after T8.

[0110] In the above steps, T4<T6, and the period after T6 is a peak period and the period after T4 is a valley period, which means that the energy storage battery can be charged during the valley period. Therefore, the energy storage module 300 can be started to supply power after T6.

[0111] If T4<T6 and the period after T4 is peak, it means that charging cannot be completed during valley time. Therefore, it is necessary to calculate how much power can be charged to the energy storage module 300 during the remaining time during valley time, and then calculate the remaining power supply time T7 based on the calculated battery SOC and P3, and then calculate the remaining power supply time T8 through T1-T7. After passing T8, whether it is peak time or valley time, the optimal power supply time of the energy storage module 300 is determined.

[0112] In another embodiment, step S700 further includes a step of verifying the prediction result, and the verification step specifically includes:

[0113] S810. Set verification time based on T1.

[0114] In one embodiment, the verification time is N*T1, where N is less than 1.

[0115] S820. After the verification time, the preset model is used again to predict the time T2 when the diesel power + photovoltaic power - load power > c.

[0116] S830 , comparing T1 and T2 , and judging based on the comparison result whether to re-output the control strategy for charging or discharging the energy storage module 300 based on T2 and the battery SOC condition.

[0117] In the above steps, the step of comparing T1 and T2 is specifically to determine whether T2+N*T1 is greater than T1. If T2+N*T1>T1, it means that the time after verification when diesel power+PV power-load power>c is greater than T1, so there is a problem with the control strategy of charging or discharging the energy storage module 300 outputted by T1 before, and it is necessary to re-execute step S700 according to T2, that is, based on T2 and the battery SOC, output the control strategy of charging or discharging the energy storage module 300.

[0118] If T2+N*T1<T1, it proves that diesel power+PV power-load power>c at T1 is accurate, and the control strategy of charging or discharging the energy storage module 300 outputted at T1 can be continued.

[0119] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A photovoltaic, energy-storage, diesel, AC and DC microgrid system, characterized by: The invention comprises a photovoltaic module (100), a diesel generator module (200), an energy storage module (300), an energy storage converter PCS (400), a DCDC converter (500), an STS intelligent switching cabinet (600) and an energy management module (700), wherein the photovoltaic module (100) and the energy storage module (300) are electrically connected to the STS intelligent switching cabinet (600) via the energy storage converter PCS (400), and the diesel generator module (200) is electrically connected to the STS intelligent switching cabinet (600). 0) electrical connection, the STS intelligent switching cabinet (600) is connected to the user-side load, the diesel generator module (200), the energy storage module (300), the energy storage converter PCS (400), the DCDC converter (500) and the STS intelligent switching cabinet (600) are all communicatively connected to the energy management module (700), and the energy management module (700) controls the photovoltaic module (100), the diesel generator module (200), the energy storage module (300) and the power grid to supply power to the user-side load; The specific control method of the energy management module (700) includes: Acquiring the photovoltaic power of the photovoltaic module (100) and the battery SOC of the energy storage module (300); When the battery SOC is lower than a lower limit and the photovoltaic power minus the load power < a, the diesel generator module (200) is controlled to start; when the battery SOC is higher than an upper limit and the photovoltaic power minus the load power > b, the diesel generator module (200) is controlled to shut down; wherein when the diesel generator module (200) is started, a grid-connected mode is started, and when the diesel generator module (200) is shut down, an off-grid mode is started; In the grid-connected mode, when the diesel generator power + photovoltaic power of the diesel generator module (200) is greater than the load power, the diesel generator module (200) is controlled to charge the energy storage module (300); In the grid-connected mode, when the diesel power + photovoltaic power < load power, it is determined whether the electricity price is at peak or valley time; If it is at peak time, based on the battery SOC condition, controlling the energy storage module (300) and / or the power grid to supply power to the user-side load; If it is in the valley period, historical photovoltaic power data and meteorological data are obtained, and the time T1 when the diesel power + photovoltaic power - load power > c is predicted by a preset model, and based on T1 and the battery SOC condition, a control strategy for charging or discharging the energy storage module (300) is output.

2. The photovoltaic, energy-storage, diesel, AC and DC microgrid system according to claim 1 is characterized by: The step of controlling the energy storage module (300) and / or the power grid to supply power to the user-side load based on the battery SOC condition specifically comprises: When the battery SOC is higher than the upper limit, if the load power is greater than the maximum power of the PCS, the energy storage module (300) and the power grid jointly supply power to the load side; if the load power is less than the maximum power of the PCS, the energy storage module (300) alone supplies power to the load side; When the battery SOC is higher than a lower limit and lower than an upper limit, the energy storage module (300) and the power grid jointly supply power to the load side; When the battery SOC is lower than the lower limit, the power grid supplies power to the load side alone.

3. The photovoltaic, energy-storage, diesel, AC and DC microgrid system according to claim 1 is characterized by: The step of outputting the control strategy for charging or discharging the energy storage module (300) based on T1 and the battery SOC condition specifically comprises: If T1 is in the valley, when the diesel power + photovoltaic power - load power > d, the grid power supply is stopped; If T1 is at the peak time, compare P1, P2 and P3, and take the larger value to calculate the power supply time T2 of the energy storage module (300) under the current battery SOC, and calculate the power supply time T3, wherein T3=T1-T2, P1 is the current load power, P2 is the maximum historical average load power in the historical valley time, and P3 is the maximum historical average load power in the historical peak time; Based on T2, T3 and the battery SOC, the charging and discharging conditions of the energy storage module (300) are determined.

4. The photovoltaic, energy-storage, diesel, AC and DC microgrid system according to claim 3 is characterized by: The step of determining the charging and discharging conditions of the energy storage module (300) based on T2, T3 and the battery SOC specifically comprises: If the battery SOC is higher than the upper limit, the energy storage module (300) supplies power after T3; If the battery SOC is lower than the upper limit but higher than the lower limit, it is determined whether it is in the valley time after T3, and if so, the energy storage module (300) is powered after T3; if not or the battery SOC is lower than the lower limit, the time T4 required for the energy storage module (300) to be fully charged and the power supply time T5 of the energy storage module (300) when fully charged are calculated, and the charging time and power supply time point of the energy storage module (300) are determined.

5. The photovoltaic, energy-storage, diesel, AC and DC microgrid system according to claim 4 is characterized by: The step of determining the charging duration and power supply time point of the energy storage module (300) specifically comprises: Calculate the available power supply time T6, T6= T1-T5; If T4>T6, and the period after T4 is a valley period, the energy storage module (300) is charged, and the energy storage module (300) is started to supply power during a peak period; If T4>T6, and the period after T4 is a peak period, then the SOC of the battery after the energy storage module (300) is calculated based on the remaining time during the valley period, and based on the calculated battery SOC and P3, the remaining available power supply time T7 and the remaining available power supply time T8 are calculated; if the period after T8 is a peak period, then the energy storage module (300) is started to supply power after T8; if the period after T8 is a valley period, then the energy storage module (300) is started to supply power during the peak period; If T4<T6, and the time after T6 is a valley time, the energy storage module (300) is charged, and then the energy storage module (300) is charged; If T4 is less than T6, and the period after T6 is a peak period, it is determined whether the period after T4 is a valley period; if so, the energy storage module (300) is charged, and the energy storage module (300) is started to supply power after T6; if not, the battery SOC of the energy storage module (300) after charging is calculated based on the remaining time during the valley period, and the remaining power supply time T7 and the remaining power supply time T8 are calculated based on the calculated battery SOC and P3, and the energy storage module (300) is started to supply power after T8.

6. A photovoltaic, energy-storage, diesel, AC / DC microgrid system according to any one of claims 1 to 5, characterized in that: After the step of acquiring historical photovoltaic power data and meteorological data, predicting the time T1 when diesel power + photovoltaic power - load power > c through a preset model, and outputting a control strategy for charging or discharging the energy storage module (300) based on T1 and the battery SOC, the step further includes: Set verification time based on T1; After the verification time, the preset model is used to predict the time T2 when the diesel power + photovoltaic power - load power > c; Compare T1 and T2, and determine based on the comparison result whether to re-output the control strategy for charging or discharging the energy storage module (300) based on T2 and the battery SOC condition.

7. The photovoltaic, energy-storage, diesel, AC and DC microgrid system according to claim 6 is characterized by: The verification time is N*T1, where N is less than 1; The step of comparing T1 and T2 specifically comprises determining whether T2+N*T1 is greater than T1, and if so, re-outputting the control strategy for charging or discharging the energy storage module (300).

8. The photovoltaic, energy-storage, diesel, AC / DC microgrid system according to claim 1 or 3, characterized in that: If T1 is greater than 24 hours, the power grid is maintained to supply power to the load side alone, and the energy storage module (300) is charged synchronously.

9. The photovoltaic, energy-storage, diesel, AC and DC microgrid system according to claim 8 is characterized by: If T1 is greater than 24 hours, the power grid is kept supplying power to the load side alone and the energy storage module (300) is charged synchronously. If the electricity price is at a peak or the battery SOC is higher than an upper limit, the energy storage module (300) is stopped from being charged; and the time T1 is re-predicted every preset time.

10. The photovoltaic, energy-storage, diesel, AC and DC microgrid system according to claim 3 is characterized by: 0KW<c<a<b, 0KW<d<a<b.

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