Light storage direct-quadrature hybrid flexible power distribution method for construction site board room area

Abstract

The application discloses a kind of light storage direct intersection mixed flexible power distribution methods for construction site board room area, bag following steps: step 1: the alternating current that municipal power grid (1) is transported is preferentially used for the power consumption of air conditioner (2) and dining room (3) in construction site board room area, the power consumption of office equipment (7) and lighting equipment (8) is preferentially used for photovoltaic cell panel (4) electricity;Step 2: the power consumption of office equipment (7) and lighting equipment (8) is counted, and the capacity of energy storage battery (6) is designed;Step 3: according to the power consumption of office equipment (7) and lighting equipment (8) and the capacity of energy storage battery (6), combined with peak-valley electricity price formulation power consumption operation strategy, maximize the use of photovoltaic cell panel (4) photovoltaic resources, reduce the power consumption cost from municipal power grid (1).The application can flexibly allocate photovoltaic cell panel and municipal power grid power supply, satisfy the power consumption mode of construction site board room.

Description

Technical Field

[0001] This invention relates to a power distribution method, and more particularly to a flexible power distribution method using a hybrid direct-AC hybrid system of photovoltaic and energy storage for prefabricated housing areas in construction sites. Background Technology

[0002] As a major energy consumer and carbon emitter in my country, the construction industry, in accordance with the national energy development plan, needs to change its original role as a single user in the national energy system and become a new entity integrating production, storage, and energy consumption. Against this backdrop, the technological concept of photovoltaic-storage-direct-drive-flexible energy storage has been proposed, pointing out a technological path for buildings to effectively utilize renewable energy.

[0003] "PV-Storage-DC-Flexible" is an abbreviation for four technologies applied in the building sector: solar photovoltaic, energy storage, DC power distribution, and flexible interconnection. It is a crucial pillar for developing zero-carbon energy and facilitates the direct absorption of wind and solar power. Although this technology is being vigorously developed, it is still in its early stages, with many technical details still being explored. In terms of engineering practice, there are only a few small-scale demonstration projects, and these only involve certain building types.

[0004] Currently, research in this field mainly focuses on permanent civil buildings, while construction site prefabricated housing areas, as temporary structures, have not yet attracted researchers' attention. Compared to conventional civil buildings, construction site prefabricated housing has some unique architectural and load characteristics, which determines that solar energy application systems suitable for construction site prefabricated housing areas differ significantly from those for permanent civil buildings. For example:

[0005] 1. Because construction site prefabricated houses have fewer floors, each unit of building area has a larger roof area, so theoretically more photovoltaic panels can be installed, and the photovoltaic power generation per unit of building area is much greater than that of ordinary permanent buildings.

[0006] 2. Construction site prefabricated houses are mostly built with color steel. Because color steel prefabricated houses are relatively lightweight, their insulation and airtightness are much worse than those of formal buildings. At the same time, since the electricity cost is usually borne by the construction unit, the construction workers have relatively poor energy-saving awareness. Therefore, the heating, ventilation and air conditioning load in the construction prefabricated house area is very high.

[0007] Based on actual energy consumption surveys and photovoltaic power generation calculations, it can be concluded that the power generation of photovoltaic panels in the prefabricated construction site area can fully support all types of electricity consumption except for air conditioning, but is insufficient to support air conditioning. Therefore, the power distribution model for permanent civil buildings is not suitable for prefabricated construction sites, and flexible power distribution tailored to the specific power load characteristics of these sites is required. Summary of the Invention

[0008] The purpose of this invention is to provide a flexible power distribution method for photovoltaic and energy storage DC-AC hybrid systems in construction site prefabricated housing areas, which can flexibly allocate power from photovoltaic panels, energy storage batteries and the municipal power grid to meet the power consumption patterns of construction site prefabricated housing.

[0009] This invention is implemented as follows:

[0010] A method for flexible power distribution using a hybrid direct-AC (DC-AC) power distribution system for prefabricated areas in construction sites includes the following steps:

[0011] A hybrid direct-AC (DC-AC) power distribution method for photovoltaic-storage power distribution in prefabricated areas of construction sites includes the following steps:

[0012] Step 1: Prioritize the use of AC power from the municipal power grid for air conditioning and canteen power in the construction site's prefabricated housing area, and prioritize the use of photovoltaic power for office equipment and lighting equipment.

[0013] Step 2: Calculate the electrical load of office equipment and lighting equipment, and design the capacity of the energy storage battery;

[0014] Step 3: Based on the power load of office equipment and lighting equipment and the capacity of energy storage batteries, formulate an electricity operation strategy in conjunction with peak and off-peak electricity pricing to maximize the utilization of photovoltaic resources from photovoltaic panels and reduce electricity costs from the municipal power grid.

[0015] In step 1, the photovoltaic panels in the construction site's prefabricated housing area are divided into two groups. One group of photovoltaic panels is connected to a storage battery via a DC transformer to form a photovoltaic energy storage DC microgrid. This photovoltaic energy storage DC microgrid is connected to the office equipment and lighting equipment in the construction site's prefabricated housing area. The other group of photovoltaic panels is connected to the municipal power grid via a grid-connected inverter and used for air conditioning and canteen electricity.

[0016] The office equipment includes office instruments used in construction projects, as well as electronic devices used in daily life.

[0017] The municipal power grid is connected to office equipment and lighting equipment.

[0018] In step 2, the method for calculating the power load of office equipment and lighting equipment is as follows: statistically analyze the power load curves of office equipment and lighting equipment for several days, and estimate the annual power consumption of office equipment and lighting equipment based on the power load curves, and multiply the annual power consumption by a safety factor.

[0019] In the aforementioned photovoltaic energy storage DC microgrid, the capacity of the energy storage battery is calculated based on the maximum absolute value of the difference between the power generation of one group of photovoltaic panels and the total load of office equipment and lighting equipment over a continuous time period of 8760 hours throughout the year. The calculation formula is as follows:

[0020]

[0021] Where U is the design capacity of the energy storage battery;

[0022] h1 is the start time when the energy storage battery powers the office equipment and lighting equipment, and h2 is the end time when the energy storage battery powers the office equipment and lighting equipment.

[0023] f aqc For energy storage battery design capacity safety factor, f aqc Take 1.3;

[0024] P zm The load power of the lighting equipment;

[0025] P bg The load power of office equipment.

[0026] In step 3, the operating strategy includes:

[0027] During the first off-peak electricity price period in summer, there is no sunlight and the photovoltaic panels do not generate electricity. Instead, the energy storage batteries power office equipment and lighting equipment, while the municipal power grid is used for air conditioning and canteen electricity.

[0028] During the first flat electricity price period in summer, the sunlight is weak and the photovoltaic panels generate little electricity. The energy storage batteries power the office equipment and lighting equipment, while the municipal power grid is used for air conditioning and canteen electricity.

[0029] During the first peak electricity price period in summer, when the sunlight is strong and the photovoltaic panels generate a lot of electricity, one set of photovoltaic panels is connected to the photovoltaic energy storage DC microgrid, and the energy storage battery powers the office equipment and lighting equipment. The other set of photovoltaic panels is connected to the municipal power grid and used for air conditioning and canteen electricity.

[0030] During the second flat electricity price period in summer, the sunlight is strong and the photovoltaic panels generate a lot of electricity. One group of photovoltaic panels is connected to the photovoltaic energy storage DC microgrid and stores energy in the energy storage battery. The energy storage battery powers office equipment and lighting equipment. The other group of photovoltaic panels is connected to the municipal power grid and used for air conditioning and canteen power.

[0031] During the second peak electricity price period in summer, the operation strategy for the first peak electricity price period in summer shall be followed.

[0032] During the third flat electricity price period in summer, the operation strategy for the second flat electricity price period in summer shall be followed.

[0033] During other periods of summer, from the third flat electricity price period to the first valley electricity price period of the following day, there is no sunlight and the photovoltaic panels do not generate electricity. Therefore, there is no need to adjust the distribution of photovoltaic panels. The energy storage batteries power the office equipment and lighting equipment, and the municipal power grid is used for air conditioning and canteen electricity.

[0034] During the off-peak electricity price period outside of summer, there is no sunlight and the photovoltaic panels do not generate electricity. Instead, the energy storage batteries power office equipment and lighting equipment, while the municipal power grid is used for air conditioning and canteen electricity.

[0035] During the first flat electricity price period outside of summer, the sunlight is weak and the photovoltaic panels generate little electricity. The energy storage batteries power the office equipment and lighting equipment, while the municipal power grid is used for air conditioning and canteen electricity.

[0036] During the first peak electricity price period outside of summer, when the sunlight is strong and the photovoltaic panels generate a lot of electricity, one set of photovoltaic panels is connected to the photovoltaic energy storage DC microgrid, and the energy storage battery powers the office equipment and lighting equipment. The other set of photovoltaic panels is connected to the municipal power grid and used for air conditioning and canteen electricity.

[0037] During the second flat electricity price period outside of summer, the sunlight is strong and the photovoltaic panels generate a lot of electricity. One group of photovoltaic panels is connected to the photovoltaic energy storage DC microgrid and stores energy in the energy storage battery. The energy storage battery powers office equipment and lighting equipment. The other group of photovoltaic panels is connected to the municipal power grid and used for air conditioning and canteen electricity.

[0038] During other times outside of summer, namely from the second flat price period to the first off-peak price period of the following day, there is no sunlight and the photovoltaic panels do not generate electricity. Therefore, there is no need to adjust the distribution of photovoltaic panels. The energy storage batteries power the office equipment and lighting equipment, while the municipal power grid is used for air conditioning and canteen electricity.

[0039] During the first peak electricity price period in summer and outside the first peak electricity price period in summer, the power allocated to office equipment and lighting equipment is greater than the sum of the office load power of office equipment and the lighting load power of lighting equipment. The calculation formula is as follows:

[0040] P gz =f aq1 (P zm +P bg )

[0041] Among them, P gz Power allocated to office equipment and lighting equipment;

[0042] f aq1 The first safety factor is set to 1.05.

[0043] Pzm The load power of the lighting equipment;

[0044] P bg The load power of office equipment.

[0045] During the second flat electricity price period in summer, at the start time of the second flat electricity price period in summer, the current power U0 of the energy storage battery is detected, and the difference ΔU between the current power U0 and the design capacity U of the energy storage battery is calculated, that is: ΔU=U-U0;

[0046] The power generation of photovoltaic panels during the first peak electricity price period in summer was recorded, and the charging power of energy storage batteries during the flat electricity price period before sunset in summer was calculated based on the power generation data. The calculation method is as follows:

[0047] Obtain typical annual solar radiation intensity data P from the local meteorological station in the area where the construction site is located. i，j Where i = 1, 2, ..., 365, j = 8, 9, ..., 16, P i，j This represents the average solar radiation power per unit area in the hour following the j-th hour of the i-th day of the year.

[0048] If the first peak electricity price period in summer is from 8:00 AM to 11:00 AM, and the flat electricity price period before sunset in summer is from 11:00 AM to 1:00 PM and from 3:00 PM to 5:00 PM; let Q be the power generation per unit area of ​​photovoltaic panels during the first peak electricity price period on day i. i，8-11 Then, in the kth hour of a period before sunset in summer, which falls under the flat electricity price period, the amount of electricity generated per unit area of ​​photovoltaic panels is Q. i，k The calculation formula is:

[0049]

[0050] The number N of photovoltaic panels connected to the photovoltaic energy storage DC microgrid per hour to charge the energy storage battery. i，k The calculation formula is:

[0051]

[0052] Where F0 is the area of ​​a single photovoltaic panel.

[0053] During the second flat electricity price period outside of summer, at the start time of the second flat electricity price period outside of summer, the current charge U0 of the energy storage battery is detected, and the difference ΔU between the current charge U0 and the design capacity U of the energy storage battery is calculated, that is: ΔU=U-U0;

[0054] The power generation of photovoltaic panels during the first peak electricity price period outside of summer is recorded, and the charging power of energy storage batteries during the flat electricity price period before sunset outside of summer is calculated based on the power generation. The calculation method is as follows:

[0055] Obtain typical annual solar radiation intensity data P from the local meteorological station in the area where the construction site is located. i，j Where i = 1, 2, ..., 365, j = 8, 9, ..., 16, P i，j This represents the average solar radiation power per unit area in the hour following the j-th hour of the i-th day of the year.

[0056] If the first peak electricity price period outside of summer is from 8:00 AM to 11:00 AM, and the flat electricity price period before sunset outside of summer is from 11:00 AM to 5:00 PM; let Q be the power generation per unit area of ​​photovoltaic panels during the first peak electricity price period on day i. i，8-11 If it is not during the summer before sunset, but during the k-th hour of a period with flat electricity prices, the power generation Q per unit area of ​​photovoltaic panels is... i，k The calculation formula is:

[0057]

[0058] The number of photovoltaic panels N' connected to the photovoltaic energy storage DC microgrid per hour to charge the energy storage battery. i，k The calculation formula is:

[0059]

[0060] Where F0 is the area of ​​a single photovoltaic panel.

[0061] Compared with the prior art, the present invention has the following advantages:

[0062] 1. This invention uses a photovoltaic energy storage DC microgrid to power office equipment and lighting equipment. Under normal office and lighting power consumption conditions that are in direct contact with users, DC power is safer and can operate independently of the municipal power grid for a period of time, making it more reliable. In special circumstances, such as continuous cloudy days, it can switch back to the municipal power grid without affecting the use of office equipment and lighting equipment.

[0063] 2. This invention prioritizes the consumption of photovoltaic power generated by photovoltaic panels through a photovoltaic energy storage DC microgrid, reducing losses during the AC / DC conversion process. The overall operation strategy ensures that photovoltaic power generation is consumed as quickly as possible, greatly improving the efficiency of solar energy utilization.

[0064] 3. This invention takes into account the electricity price in the area where the construction site is located, and adjusts the operation strategy of photovoltaic panels and municipal power grid according to the electricity price and the degree of sunlight at different times. The number allocation ratio of photovoltaic panels forming the photovoltaic energy storage DC microgrid and photovoltaic panels connected to the municipal power grid can be flexibly changed and controlled according to the actual situation. It has high adaptability, can make full use of solar energy, effectively reduce the overall cost of using the municipal power grid, and thus reduce construction costs. Attached Figure Description

[0065] Figure 1 This is a circuit distribution diagram of the photovoltaic-storage DC-AC hybrid flexible power distribution method for prefabricated building areas in the present invention.

[0066] In the diagram, 1 is the municipal power grid, 2 is air conditioning, 3 is the canteen, 4 is photovoltaic panels, 5 is DC transformer, 6 is energy storage battery, 7 is office equipment, 8 is lighting equipment, and 9 is grid-connected inverter. Detailed Implementation

[0067] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0068] Please see the appendix Figure 1 A method for flexible power distribution using a hybrid direct-AC (DC-AC) power supply system for prefabricated housing areas in construction sites includes the following steps:

[0069] Step 1: Prioritize the use of AC power from the municipal power grid 1 for the air conditioning 2 and canteen 3 in the construction site prefabricated housing area, and prioritize the use of photovoltaic panels 4 for office equipment 7 and lighting equipment 8.

[0070] Since the power generation of the photovoltaic panels 4 in the construction site's prefabricated housing area is insufficient to power the air conditioner 2, AC power from the municipal power grid 1 is used to meet the power demand of the air conditioner 2. At the same time, since the total power consumption of the canteen 3 is not large, but the power consumption time is concentrated and the power consumption is large, AC power from the municipal power grid 1 is also used to ensure the normal power demand of the canteen 3.

[0071] The photovoltaic panels 4 in the construction site's prefabricated housing area are divided into two groups. One group of photovoltaic panels 4 is connected to the energy storage battery 6 via a DC transformer 5, forming a photovoltaic energy storage DC microgrid. The photovoltaic energy storage DC microgrid is connected to the office equipment 7 and lighting equipment 8 in the construction site's prefabricated housing area, and the energy storage battery 6 of the photovoltaic energy storage DC microgrid supplies power to the office equipment 7 and lighting equipment 8. The DC transformer 5 converts the DC power into a 48V DC power supply that can be used by the office equipment 7 and lighting equipment 8.

[0072] The office equipment 7 mentioned above includes not only various office instruments used in construction projects, but also various electronic devices used in daily life.

[0073] Most office equipment 7 consists of electronic and electrical devices. Both office equipment 7 and lighting equipment 8 support DC power supply. Office equipment 7 and lighting equipment 8 are typically equipped with small energy storage batteries, which also generally support DC power supply. Since the electricity generated by the photovoltaic panel 4 is DC, and the energy storage battery 6 is also charged and discharged in the form of DC, the DC power from the photovoltaic energy storage DC microgrid can be directly used to meet the power needs of office equipment 7 and lighting equipment 8. Compared to traditional solar energy storage power generation systems, the photovoltaic energy storage DC microgrid of this invention does not require photovoltaic inverters or energy storage battery inverters, which can reduce energy losses during the "DC-AC-DC" conversion process in traditional solar energy storage power generation systems, utilize photovoltaic power generation more efficiently, and reduce system costs.

[0074] Another set of photovoltaic panels 4 is connected to the municipal power grid 1 via a grid-connected inverter 9, and is used to supply power to air conditioner 2 and canteen 3, providing 380V AC power to them. Since air conditioner 2 has a large power load, the power generated by photovoltaic panels 4 can be basically consumed locally, without the need for surplus power to be fed into the grid, and will not affect the municipal power grid 1.

[0075] The municipal power grid 1 is also connected to the office equipment 7 and the lighting equipment 8 so that when the photovoltaic panel 4 is not generating electricity and the energy storage battery 6 is depleted, the power needs of the office equipment 7 and the lighting equipment 8 can be met through the municipal power grid 1.

[0076] Step 2: Calculate the power load of office equipment 7 and lighting equipment 8, and design the capacity of energy storage battery 6.

[0077] Since the power load of office equipment 7 and lighting equipment 8 is relatively stable, the power load curves of office equipment 7 and lighting equipment 8 for several days can be statistically analyzed. Based on the power load curves, the annual power consumption of office equipment 7 and lighting equipment 8 can be estimated. Based on the premise that the power generation is equal to the power consumption, after multiplying the annual power consumption by the necessary safety factor, the proportion of all the power generated by the photovoltaic panels 4 that should be allocated to the photovoltaic energy storage DC microgrid can be calculated.

[0078] Preferably, in the photovoltaic energy storage DC microgrid, the capacity of the energy storage battery 6 is calculated based on the maximum absolute value of the difference between the power generation of one group of photovoltaic panels 4 and the total load of office equipment 7 and lighting equipment 8 over a continuous time period of 8760 hours throughout the year. The calculation formula is as follows:

[0079]

[0080] Where U represents the design capacity of the energy storage battery 6.

[0081] h1 is the start time when the energy storage battery 6 supplies power to the office equipment 7 and the lighting equipment 8, and h2 is the end time when the energy storage battery 6 supplies power to the office equipment 7 and the lighting equipment 8. Preferably, h1 is 17:00 every evening and h2 is 8:00 the next morning. That is, during the period from 17:00 to 8:00 the next morning, since there is basically no sunlight, the photovoltaic panel 4 does not generate electricity or generates very little electricity. Under the condition that the energy storage battery 6 has sufficient power, the energy storage battery 6 supplies power to the office equipment 7 and the lighting equipment 8.

[0082] f aqc For the design of the energy storage battery 6, a capacity safety factor is preferably set to 1.3 to ensure that the energy storage battery 6 can still meet the usage requirements even when overtime work is required on individual nights.

[0083] P zm The load power of lighting equipment 8 is calculated from the power of all lighting equipment in the building site area.

[0084] P bg The load power of office equipment 7 is calculated from the power of all office equipment in the construction site's prefabricated housing area.

[0085] Step 3: Based on the power load of office equipment 7 and lighting equipment 8 and the capacity of energy storage battery 6, formulate an electricity operation strategy in conjunction with peak and off-peak electricity pricing to maximize the utilization of photovoltaic resources of photovoltaic panels 4 and reduce electricity costs from the municipal power grid 1.

[0086] Taking a certain city as an example, industrial and commercial time-of-use users in this city are subject to a three-stage peak-valley electricity price. In summer: the first valley electricity price period is before 6:00 AM, the first flat electricity price period is from 6:00 AM to 8:00 AM, the first peak electricity price period is from 8:00 AM to 11:00 AM, the second flat electricity price period is from 11:00 AM to 1:00 PM, the second peak electricity price period is from 1:00 PM to 3:00 PM, and the third flat electricity price period is from 3:00 PM to 5:00 PM. From 5:00 PM to 6:00 AM the next morning, the electricity price goes through the flat-peak-valley cycle.

[0087] Outside of summer: the first off-peak electricity price period is before 6:00 AM, the first flat electricity price period is from 6:00 AM to 8:00 AM, the first peak electricity price period is from 8:00 AM to 11:00 AM, the second flat electricity price period is from 11:00 AM to 5:00 PM, and the electricity price from 5:00 PM to 6:00 AM the next day goes through flat-peak-valley.

[0088] The aforementioned operating strategy includes:

[0089] During the first off-peak electricity price period in summer, there is no sunlight, so the photovoltaic panel 4 does not generate electricity. Instead, the energy storage battery 6 powers the office equipment 7 and lighting equipment 8, while the municipal power grid 1 powers the air conditioning 2 and the canteen.

[0090] During the first flat electricity price period in summer, the sunlight is relatively weak, and the photovoltaic panel 4 generates less electricity. The energy storage battery 6 powers the office equipment 7 and lighting equipment 8, while the municipal power grid 1 is used for the air conditioning 2 and the canteen.

[0091] During the first peak electricity price period in summer, the cost of electricity for municipal power grid 1 is relatively high. However, the strong sunlight during this period results in high power generation from photovoltaic panels 4. One set of photovoltaic panels 4 is connected to a photovoltaic energy storage DC microgrid, and the energy storage battery 6 supplies power to office equipment 7 and lighting equipment 8. The other set of photovoltaic panels 4 is connected to municipal power grid 1 and used for the electricity consumption of air conditioners 2 and canteen 3, thus fully and instantly absorbing photovoltaic resources and reducing the cost of municipal electricity.

[0092] During the first peak electricity price period in summer, the power allocated to office equipment 7 and lighting equipment 8 is slightly greater than the sum of the office load power of office equipment 7 and the lighting load power of lighting equipment 8. The calculation formula is as follows:

[0093] P gz =f aq1 (P zm +P bg )

[0094] Among them, P gz Power is allocated to office equipment 7 and lighting equipment 8.

[0095] f aq1 For the first safety factor, preferably 1.05, it is ensured that it can support the power of all office equipment 7 and lighting equipment 8, while there is still a small amount of surplus power generation (5%) that can be accommodated by the energy storage battery 6.

[0096] P zm The load power of lighting equipment 8.

[0097] P bg The load power of office equipment 7.

[0098] During the second flat electricity price period in summer, the sunlight is strong and the photovoltaic panel 4 generates a lot of electricity. One set of photovoltaic panels 4 is connected to the photovoltaic energy storage DC microgrid and stores energy in the energy storage battery 6. The energy storage battery 6 supplies power to office equipment 7 and lighting equipment 8. Another set of photovoltaic panels 4 is connected to the municipal power grid 1 and used for the electricity of air conditioner 2 and canteen 3, which fully and instantly consumes photovoltaic resources and reduces the cost of municipal electricity.

[0099] At the start of the second flat electricity price period in summer, the automatic control system detects the current charge U0 of the energy storage battery 6 and calculates the difference ΔU between the current charge U0 and the design capacity U of the energy storage battery 6, i.e.:

[0100] △U=U-U0.

[0101] The use of photovoltaic panels 4 to charge energy storage batteries 6 is scheduled during periods of relatively low electricity prices.

[0102] The radiant power projected onto the surface of photovoltaic panel 4 at various times each day is mainly related to three factors: weather conditions, solar altitude angle, and solar azimuth angle. Among these, the variation patterns of solar altitude angle and solar azimuth angle are fixed. Therefore, by controlling the power generation of photovoltaic panel 4 during the first peak electricity price period of summer (8-11 AM), as recorded by the control system, the charging power of energy storage battery 6 during the flat electricity price period before sunset in summer can be calculated. The specific calculation process is as follows:

[0103] Obtain typical annual solar radiation intensity data P from the local meteorological station in the area where the construction site is located. i，j Where i = 1, 2, ..., 365, j = 8, 9, ..., 16, P i，j It represents the average solar radiation power per unit area in the hour following the j-th hour of the i-th day of the year.

[0104] Taking the first peak electricity price period in summer as an example, which is from 8:00 AM to 11:00 AM:

[0105] Let Q be the power generation per unit area of ​​photovoltaic panel 4 during the first peak electricity price period on the morning of day i. i，8-11 If, during the k-th hour of a period with flat electricity prices before sunset in summer, the power generation per unit area of ​​photovoltaic panels 4 can be calculated as follows:

[0106]

[0107] If the peak electricity pricing period before sunset in summer is 11:00-13:00 and 15:00-17:00, then the power generation Q per unit area of ​​photovoltaic panels 4 during these periods can be calculated using the above formula. i，k .

[0108] The number of photovoltaic panels 4 connected to the photovoltaic energy storage DC microgrid each hour to charge the energy storage battery 6 can be calculated using the following formula:

[0109]

[0110] Where, N i，k Let be the number of photovoltaic panels 4 connected to the photovoltaic energy storage DC microgrid in the kth hour of day i to charge the energy storage battery 6.

[0111] F0 represents the area of ​​a single photovoltaic panel 4.

[0112] Based on the above calculations, energy storage tasks can be allocated according to the differences in solar radiation intensity at different times of summer. This ensures that the number of photovoltaic panels 4 connected to the photovoltaic energy storage DC microgrid is consistent during the flat electricity price period, which can avoid frequent switching and reduce the service life of electrical components.

[0113] During the second peak electricity price period in summer, the system can operate according to the same strategy as the first peak electricity price period. That is, the energy storage battery 6 supplies power to the office equipment 7 and lighting equipment 8, while another set of photovoltaic panels 4 is connected to the municipal power grid 1 and used for the electricity consumption of air conditioner 2 and canteen 3, so as to fully and instantly utilize photovoltaic resources and reduce municipal electricity costs.

[0114] During the third flat-price period in summer, the operation strategy for the second flat-price period can be followed. That is, the energy storage battery 6 stores electricity and supplies power to office equipment 7 and lighting equipment 8, and the number N of photovoltaic panels 4 allocated in the photovoltaic energy storage DC microgrid is calculated. i，k .

[0115] During other periods of summer, from the third flat electricity price period to the first valley electricity price period of the following day, there is almost no sunlight, and the photovoltaic panels 4 basically do not generate electricity. There is no need to adjust the distribution of the photovoltaic panels 4. The energy storage battery 6 supplies power to the office equipment 7 and lighting equipment 8, and the municipal power grid 1 is used for the electricity consumption of air conditioners 2 and canteens.

[0116] Outside of summer, unlike summer when there is no second peak electricity price period and a third flat electricity price period, the operating strategies for the periods containing the second peak electricity price period and the third flat electricity price period are the same as those for the second flat electricity price period. The specific operating strategies are as follows:

[0117] During the off-peak electricity price period outside of summer, there is no sunlight, so the photovoltaic panel 4 does not generate electricity. Instead, the energy storage battery 6 powers the office equipment 7 and lighting equipment 8, while the municipal power grid 1 powers the air conditioning 2 and the canteen.

[0118] During the first flat electricity price period outside of summer, the sunlight is relatively weak, and the photovoltaic panel 4 generates less electricity. The energy storage battery 6 powers the office equipment 7 and lighting equipment 8, while the municipal power grid 1 is used for the air conditioning 2 and the canteen.

[0119] During the first peak electricity price period outside of summer, the cost of electricity for municipal power grid 1 is relatively high. However, during this period, the sunlight is strong, and the power generation of photovoltaic panels 4 is high. One set of photovoltaic panels 4 is connected to a photovoltaic energy storage DC microgrid, and the energy storage battery 6 supplies power to office equipment 7 and lighting equipment 8. The other set of photovoltaic panels 4 is connected to municipal power grid 1 and used for the power supply of air conditioner 2 and canteen 3, so as to fully and timely absorb photovoltaic resources and reduce the cost of municipal electricity.

[0120] During the first peak electricity price period outside of summer, the power allocated to office equipment 7 and lighting equipment 8 is slightly greater than the sum of the office load power of office equipment 7 and the lighting load power of lighting equipment 8. The calculation formula is as follows:

[0121] P gz =f aq1 (P zm +P bg )

[0122] Among them, P gz Power is allocated to office equipment 7 and lighting equipment 8.

[0123] f aq1 For the first safety factor, preferably 1.05, it is ensured that it can support the power of all office equipment 7 and lighting equipment 8, while there is still a small surplus of power generation (5%) that can be accommodated by the energy storage battery 6.

[0124] P zm The load power of lighting equipment 8.

[0125] P bg The load power of office equipment 7.

[0126] During the second flat electricity price period outside of summer, the sunlight is strong, and the photovoltaic panels 4 generate a lot of electricity. One set of photovoltaic panels 4 is connected to the photovoltaic energy storage DC microgrid and stores energy in the energy storage battery 6. The energy storage battery 6 supplies power to office equipment 7 and lighting equipment 8. The other set of photovoltaic panels 4 is connected to the municipal power grid 1 and used for the electricity consumption of air conditioner 2 and canteen 3, which fully and instantly consumes photovoltaic resources and reduces the cost of municipal electricity.

[0127] At the start of the second flat-price electricity period outside of summer, the automatic control system detects the current charge U0 of energy storage battery 6 and calculates the difference ΔU between the current charge U0 and the design capacity U of energy storage battery 6, i.e.:

[0128] △U=U-U0.

[0129] The use of photovoltaic panels 4 to charge energy storage batteries 6 is scheduled during periods of relatively low electricity prices.

[0130] The radiant power projected onto the surface of photovoltaic panel 4 at various times each day is mainly related to three factors: weather conditions, solar altitude angle, and solar azimuth angle. Among these, the variation patterns of solar altitude angle and solar azimuth angle are fixed. Therefore, the power generation of photovoltaic panel 4 during the first peak electricity price period (8-11 AM) outside of summer, recorded by the control system, can be used to calculate the charging power of energy storage battery 6 during the flat electricity price period before sunset outside of summer. The specific calculation process is as follows:

[0131] Obtain typical annual solar radiation intensity data P from the local meteorological station in the area where the construction site is located. i，j Where i = 1, 2, ..., 365, j = 8, 9, ..., 16, P i，j It represents the average solar radiation power per unit area in the hour following the j-th hour of the i-th day of the year.

[0132] Let Q be the power generation per unit area of ​​photovoltaic panel 4 during the first peak electricity price period on the morning of day i. i，8-11 For a given hour (k) outside of the summer sunset period when electricity prices are flat, the power generation per unit area of ​​photovoltaic panels 4 can be calculated as follows:

[0133]

[0134] If the flat electricity price period before sunset is not during the summer (11:00-17:00), then the power generation Q per unit area of ​​photovoltaic panels 4 during this period can be calculated using the above formula. i，k .

[0135] The number of photovoltaic panels 4 connected to the photovoltaic energy storage DC microgrid each hour to charge the energy storage battery 6 can be calculated using the following formula:

[0136]

[0137] Where, N′ i，k Let be the number of photovoltaic panels 4 connected to the photovoltaic energy storage DC microgrid in the kth hour of day i to charge the energy storage battery 6.

[0138] F0 represents the area of ​​a single photovoltaic panel 4.

[0139] Based on the above calculations, energy storage tasks can be allocated according to the differences in solar radiation intensity at different times outside of summer. This ensures that the number of photovoltaic panels 4 connected to the photovoltaic energy storage DC microgrid is consistent during the flat electricity price period, which can avoid frequent switching and reduce the service life of electrical components.

[0140] During other times outside of summer, namely from the second flat electricity price period to the first valley electricity price period of the following day, there is almost no sunlight during this period. The photovoltaic panels 4 generate almost no electricity, so there is no need to adjust the distribution of the photovoltaic panels 4. The energy storage battery 6 supplies power to the office equipment 7 and lighting equipment 8, and the municipal power grid 1 is used for the electricity consumption of air conditioners 2 and canteens.

[0141] Example 1:

[0142] Taking the power distribution system of a construction site in Shanghai as an example, the temporary construction area includes office, living, and canteen areas, all three-story buildings totaling 3,000 square meters. The total installation area of ​​the rooftop photovoltaic panels 4 is 1,000 square meters. The total power generation of the entire photovoltaic system is 80 kW. The maximum load for lighting is 12 kW, the office load is 25 kW, and the air conditioning load is 100 kW. Obviously, the power generation of the photovoltaic system can handle the power load of lighting equipment 8 and office equipment 7, but not the air conditioning load 2. Therefore, the power consumption of lighting equipment 8 and office equipment 7 is directly supplied by the power generated by the photovoltaic panels 4 between 8:00 AM and 5:00 PM, and between 5:00 PM and 8:00 AM the next day, the power is supplied by the photovoltaic power stored in the energy storage battery 6. In other words, the design capacity of the energy storage battery 6 should be able to meet the power needs of the lighting equipment 8 and office equipment 7 from 5 pm to 8 am the next day. According to the actual on-site measurement, it is estimated that about 30 kWh of electricity is needed. Considering the special circumstances of a large number of people working overtime at night, multiply by a safety factor of 1.3, the capacity of the energy storage battery 6 is about 40 kWh.

[0143] Electricity prices are roughly the same in summer and non-summer. The only difference is that from 13:00 to 15:00 in summer, electricity is charged at peak prices, while it is charged at parity prices in non-summer. The switching principle for photovoltaic panels 4 is consistent. From 8:00 to 11:00 in the morning, during peak electricity prices, photovoltaic power generation should be consumed as much as possible immediately. The power consumption of office equipment 7 and lighting equipment 8 is relatively stable, with lighting load at 12kW and office load at 25kW. Therefore, the power allocated from the photovoltaic modules to the loads of lighting equipment 8 and office equipment 7 is 37kW. Of course, in actual operation, the photovoltaic power generation allocated to this load needs to be determined based on the voltage fluctuations of the photovoltaic energy storage DC microgrid. The DC bus voltage needs to be maintained at 48V to ensure the normal operation of office equipment 7 and lighting equipment 8. The other photovoltaic panels 4 are connected to the municipal power supply to power the loads of air conditioner 2 and canteen 3.

[0144] The sunny period during the day is from 8:00 AM to 5:00 PM. During this time, the summer grid parity period is from 11:00 AM to 1:00 PM and from 3:00 PM to 5:00 PM, totaling 4 hours. The non-summer grid parity period is the full 11:00 AM to 5:00 PM, totaling 6 hours. According to the control logic of this invention, a certain number of photovoltaic panels 4 need to be added to the photovoltaic energy storage DC microgrid during the sunny, grid parity period to charge the energy storage battery 6. The specific allocation quantity can be determined as follows:

[0145] First, at 11:00 AM, the energy management system can collect the current power level of the energy storage battery 6 and calculate the power gap that needs to be charged and stored by the photovoltaic panels 4 during the day. Assuming that the energy storage battery 6 has 10 kWh remaining, it needs to be charged by 30 kWh to fully charge, in preparation for the load on office equipment 7 and lighting equipment 8 in the evening. Simultaneously, the energy management system records the total power generation of the photovoltaic system between 8:00 AM and 11:00 AM. Dividing this by the number of photovoltaic panels yields the power generation of a single photovoltaic panel 4 during this period. The intensity of solar radiation reaching the ground at different times of day throughout the year follows a regular pattern. Based on records from the nearby meteorological station, the hourly solar radiation intensity can be calculated. Assuming that on a summer day, the total solar radiation intensity between 11:00 AM and 1:00 PM and between 3:00 PM and 5:00 PM is twice that between 8:00 AM and 11:00 AM, according to historical meteorological data, the power generation of each photovoltaic panel 4 will also be twice that of the solar radiation system. Using the power generation of each photovoltaic panel 4 measured by the energy management system between 8 and 11 am, assuming it is 0.5 kWh, then a single photovoltaic panel 4 can generate 1 kWh during the two periods of 11-1 pm and 3-5 pm. A total of 30 photovoltaic modules are needed to generate 30 kWh. Therefore, in order to fully charge the energy storage battery 6 during the daytime electricity parity period, in addition to the normal load on office equipment 7 and lighting equipment 8, 30 photovoltaic panels 4 need to be connected to the photovoltaic energy storage DC microgrid to charge the energy storage battery 6.

[0146] Similarly, in non-summer seasons, simply replace the 11-13 and 15-17 time periods with 11-17. Allocate the energy storage task to these 6 hours. The calculation of the required power generation of a single photovoltaic panel 4 during these 6 hours is still based on the ratio of the total solar radiation intensity during this period to that during 8-11 am. Then, the actual number of photovoltaic panels 4 that need to be transferred in can be calculated based on the power gap of the energy storage battery 6.

[0147] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A flexible power distribution method using a hybrid direct-AC (DC-AC) power distribution system for prefabricated housing areas in construction sites, characterized by: Includes the following steps: Step 1: Prioritize the use of AC power from the municipal power grid (1) for the air conditioning (2) and canteen (3) in the construction site prefabricated housing area, and prioritize the use of the power from the photovoltaic panels (4) for office equipment (7) and lighting equipment (8); Step 2: Calculate the power load of office equipment (7) and lighting equipment (8), and design the capacity of energy storage battery (6); Step 3: Based on the power load of office equipment (7) and lighting equipment (8) and the capacity of energy storage battery (6), formulate an operation strategy for electricity use in conjunction with peak and off-peak electricity prices, maximize the use of photovoltaic resources of photovoltaic panels (4), and reduce the cost of electricity from the municipal power grid (1); In step 3, the operating strategy includes: During the first off-peak electricity price period in summer, there is no sunlight, and the photovoltaic panels (4) do not generate electricity. The energy storage batteries (6) supply power to the office equipment (7) and lighting equipment (8), while the municipal power grid (1) is used for the electricity consumption of air conditioners (2) and canteens. During the first flat electricity price period in summer, the sunlight is weak and the photovoltaic panels (4) generate little electricity. The energy storage batteries (6) supply power to the office equipment (7) and lighting equipment (8), while the municipal power grid (1) is used for the electricity consumption of air conditioners (2) and canteens. During the first peak electricity price period in summer, the sunlight is strong and the photovoltaic panels (4) generate a lot of electricity. One set of photovoltaic panels (4) is connected to the photovoltaic energy storage DC microgrid, and the energy storage battery (6) supplies power to office equipment (7) and lighting equipment (8). The other set of photovoltaic panels (4) is connected to the municipal power grid (1) and used for the electricity consumption of air conditioners (2) and canteen (3). During the second flat electricity price period in summer, the sunlight is strong and the photovoltaic panels (4) generate a lot of electricity. One set of photovoltaic panels (4) is connected to the photovoltaic energy storage DC microgrid and stores energy in the energy storage battery (6). The energy storage battery (6) supplies power to office equipment (7) and lighting equipment (8). Another set of photovoltaic panels (4) is connected to the municipal power grid (1) and used for the electricity consumption of air conditioners (2) and canteen (3). During the second peak electricity price period in summer, the operation strategy for the first peak electricity price period in summer shall be followed. During the third flat electricity price period in summer, the operation strategy for the second flat electricity price period in summer shall be followed. During other periods of summer, namely from the third flat electricity price period to the first valley electricity price period of the next day, there is no sunlight during this period, the photovoltaic panels (4) do not generate electricity, there is no need to adjust the distribution of the photovoltaic panels (4), the energy storage battery (6) supplies power to the office equipment (7) and lighting equipment (8), and the municipal power grid (1) is used for the electricity consumption of air conditioning (2) and canteen. During the first off-peak electricity price period outside of summer, there is no sunlight and the photovoltaic panels (4) do not generate electricity. The energy storage batteries (6) supply power to the office equipment (7) and lighting equipment (8), while the municipal power grid (1) is used for the electricity consumption of air conditioners (2) and canteens. During the first flat electricity price period outside of summer, the sunlight is weak and the photovoltaic panels (4) generate little electricity. The energy storage batteries (6) supply power to the office equipment (7) and lighting equipment (8), while the municipal power grid (1) is used for the electricity consumption of air conditioners (2) and canteens. During the first peak electricity price period outside of summer, when the sunlight is strong, the photovoltaic panels (4) generate a lot of electricity. One set of photovoltaic panels (4) is connected to the photovoltaic energy storage DC microgrid, and the energy storage battery (6) supplies power to the office equipment (7) and lighting equipment (8). The other set of photovoltaic panels (4) is connected to the municipal power grid (1) and used for the electricity consumption of air conditioning (2) and canteen (3). During the second flat electricity price period outside of summer, the sunlight is strong and the photovoltaic panels (4) generate a lot of electricity. One set of photovoltaic panels (4) is connected to the photovoltaic energy storage DC microgrid and stores energy in the energy storage battery (6). The energy storage battery (6) supplies power to office equipment (7) and lighting equipment (8). Another set of photovoltaic panels (4) is connected to the municipal power grid (1) and used for the electricity consumption of air conditioners (2) and canteen (3). During other times outside of summer, namely from the second flat electricity price period to the first valley electricity price period of the next day, there is no sunlight during this period, the photovoltaic panels (4) do not generate electricity, there is no need to adjust the distribution of the photovoltaic panels (4), the energy storage battery (6) supplies power to the office equipment (7) and lighting equipment (8), and the municipal power grid (1) is used for the electricity consumption of air conditioning (2) and canteen. During the first peak electricity price period in summer and outside the first peak electricity price period in summer, the power allocated to office equipment (7) and lighting equipment (8) is greater than the sum of the office load power of office equipment (7) and the lighting load power of lighting equipment (8). The calculation formula is as follows: ； Among them, P gz The power allocated to office equipment (7) and lighting equipment (8); f aq1 The first safety factor is set to 1.

05. P zm The load power of the lighting equipment (8); P bg The load power of office equipment (7); During the second flat electricity price period in summer, at the start time of the second flat electricity price period in summer, the current power U0 of the energy storage battery (6) is detected, and the difference △U between the current power U0 and the design capacity U of the energy storage battery (6) is calculated, that is: △U=U-U0; The power generation of photovoltaic panels (4) during the first peak electricity price period in summer was recorded, and the charging power of energy storage batteries (6) during the flat electricity price period before sunset in summer was calculated based on the power generation. The calculation method is as follows: Obtain typical annual solar radiation intensity data P from the local meteorological station in the area where the construction site is located. i，j Where i = 1, 2, ..., 365, j = 8, 9, ..., 16, P i，j This represents the average solar radiation power per unit area in the hour following the j-th hour of the i-th day of the year. If the first peak electricity price period in summer is from 8:00 AM to 11:00 AM, and the flat electricity price period before sunset in summer is from 11:00 AM to 1:00 PM and from 3:00 PM to 5:00 PM; let Q be the power generation per unit area of ​​photovoltaic panels (4) during the first peak electricity price period on the i-th day. i，8-11 Then, in the summer before sunset, during the kth hour of the flat electricity price period, the power generation per unit area of ​​photovoltaic panels (4) is Q. i，k The calculation formula is: ； The number N of photovoltaic panels (4) connected to the photovoltaic energy storage DC microgrid per hour to charge the energy storage battery (6) i，k The calculation formula is: ； Where F0 is the area of ​​a single photovoltaic panel (4); During the second flat electricity price period in non-summer, at the start time of the second flat electricity price period in non-summer, the current power U0 of the energy storage battery (6) is detected, and the difference △U between the current power U0 and the design capacity U of the energy storage battery (6) is calculated, that is: △U=U-U0; The power generation of photovoltaic panels (4) during the first peak electricity price period outside of summer was recorded, and the charging power of energy storage batteries (6) during the flat electricity price period before sunset outside of summer was calculated based on the power generation. The calculation method is as follows: Obtain typical annual solar radiation intensity data P from the local meteorological station in the area where the construction site is located. i，j Where i = 1, 2, ..., 365, j = 8, 9, ..., 16, P i，j This represents the average solar radiation power per unit area in the hour following the j-th hour of the i-th day of the year. If the first peak electricity price period is not during summer (8-11 am), and the flat electricity price period before sunset is not during summer (11-5 pm); let Q be the power generation per unit area of ​​photovoltaic panels (4) during the first peak electricity price period on day i. i，8-11 If it is not a certain hour before sunset in summer, which belongs to the flat electricity price period, then the power generation per unit area of ​​photovoltaic panels (4) is Q. i，k The calculation formula is: ； The number of photovoltaic panels (4) connected to the photovoltaic energy storage DC microgrid each hour for charging the energy storage battery (6) is N' i，k The calculation formula is: ； Where F0 is the area of ​​a single photovoltaic panel (4).

2. The method for flexible power distribution using a hybrid direct-AC / direct-current power distribution system for prefabricated housing areas in construction sites, as described in claim 1, is characterized in that: In step 1, the photovoltaic panels (4) in the construction site prefabricated housing area are divided into two groups. One group of photovoltaic panels (4) is connected to the energy storage battery (6) through a DC transformer (5) to form a photovoltaic energy storage DC microgrid. The photovoltaic energy storage DC microgrid is connected to the office equipment (7) and lighting equipment (8) in the construction site prefabricated housing area. The other group of photovoltaic panels (4) is connected to the municipal power grid (1) through a grid-connected inverter (9) and used for the electricity consumption of air conditioning (2) and canteen (3).

3. The flexible power distribution method for photovoltaic-storage direct-AC hybrid power distribution in prefabricated building areas according to claim 1 or 2, characterized in that: The office equipment (7) includes office instruments used in construction projects, and also includes electronic devices used in daily life.

4. The flexible power distribution method for photovoltaic-storage direct-AC hybrid power distribution in prefabricated building areas according to claim 1, characterized in that: The municipal power grid (1) is connected to office equipment (7) and lighting equipment (8).

5. The flexible power distribution method for photovoltaic-storage direct-AC hybrid power distribution in prefabricated building areas according to claim 1, characterized in that: In step 2, the calculation method for the power load of office equipment (7) and lighting equipment (8) is as follows: statistically analyze the power load curves of office equipment (7) and lighting equipment (8) for several days, and calculate the annual power consumption of office equipment (7) and lighting equipment (8) based on the power load curves, and multiply the annual power consumption by a safety factor.

6. The flexible power distribution method for photovoltaic-storage direct-AC hybrid power distribution in prefabricated building areas according to claim 2, characterized in that: In the aforementioned photovoltaic energy storage DC microgrid, the capacity of the energy storage battery (6) is calculated based on the maximum absolute value of the difference between the power generation of one group of photovoltaic panels (4) and the total load of office equipment (7) and lighting equipment (8) over a continuous time period of 8760 hours throughout the year. The calculation formula is as follows: ； Where U is the design capacity of the energy storage battery (6); h1 is the start time when the energy storage battery (6) supplies power to the office equipment (7) and the lighting equipment (8), and h2 is the end time when the energy storage battery (6) supplies power to the office equipment (7) and the lighting equipment (8). f aqc For the energy storage battery (6), the capacity safety factor is designed, f aqc Take 1.3; P zm The load power of the lighting equipment (8); P bg The load power of office equipment (7).

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