Wind and light storage automobile charging system and control method

Abstract

The invention discloses a wind and light storage automobile charging system and a control method, and relates to the technical field of power supply and distribution, and the system comprises a transformer, a first AC / DC converter, an energy storage system, a first DC / DC converter, a charging gun, a photovoltaic array, a second DC / DC converter, a wind driven generator, a second AC / DC converter and a power divider. The power divider obtains the charging power requirement of the charging gun, the real-time photovoltaic power generation power of the photovoltaic array, the real-time wind power generation power of the wind power generator and the discharging power of the energy storage system. And selecting equipment for supplying power to the power divider according to the actual conditions of the charging power demand, the real-time photovoltaic power generation power, the real-time wind power generation power and the discharging power. The photovoltaic array and the wind driven generator are added, so that the capacity of the energy storage system can be reduced, the photovoltaic array and the wind driven generator can charge the energy storage system, the capacity of the energy storage system is increased invisibly, and the suppression effect on power grid fluctuation is remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of power supply and distribution technology, and in particular to a wind-solar-storage vehicle charging system and a control method. Background Art

[0002] Electric vehicles, including passenger cars and engineering vehicles, have gradually begun to be used on a large scale. Although electric vehicles do not consume fuel, they need to be charged. Affected by the use time, electricity prices, etc., the charging behavior of electric vehicles also has obvious tidal phenomena. Taking passenger cars as an example, 12 noon every day is the first charging peak period, and 6 pm is the second peak period. Although the charging peak period of engineering vehicles is somewhat different from that of passenger cars, it also has a very obvious tidal phenomenon. During peak periods, the charging power demand of vehicles is very high, and charging stations often need to operate at full power, and even cannot meet the charging needs of all vehicles. During the trough period, there are almost no vehicles at the charging station, and the charging power demand is very small at this time.

[0003] In order to smooth out valleys and suppress peak loads, many charging stations use energy storage batteries as backup power sources. The energy storage batteries are charged during valley periods, and during peak periods, both the power grid and the energy storage batteries are used as power sources. This can effectively reduce the load difference between the power grid during peak and valley periods, and is helpful in smoothing out fluctuations in the power grid.

[0004] However, the capacity of energy storage batteries is limited, and the price of energy storage batteries is not low at this stage, resulting in high costs for large-capacity energy storage batteries, while small-capacity energy storage batteries are not very effective in suppressing grid fluctuations. Summary of the invention

[0005] The embodiments of the present application provide a wind-solar-storage vehicle charging system and a control method to solve the problems in the prior art.

[0006] On the one hand, an embodiment of the present application provides a wind-solar-storage vehicle charging system, comprising a transformer, a first AC / DC (alternating current / direct current) converter, an energy storage system, a first DC / DC (direct current / direct current) converter and a charging gun which are electrically connected in sequence, and also comprises a photovoltaic array, a second DC / DC converter, a wind turbine, a second AC / DC converter and a power distributor, wherein the photovoltaic array, the second DC / DC converter and the energy storage system are electrically connected in sequence, the wind turbine, the second AC / DC converter and the energy storage system are electrically connected in sequence, the power distributor is electrically connected between the energy storage system and the first DC / DC converter, and the second DC / DC converter and the second AC / DC converter are electrically connected to the power distributor respectively; The power distributor obtains the charging power demand of the charging gun, the real-time photovoltaic power generation of the photovoltaic array, the real-time wind power generation of the wind turbine and the real-time remaining power of the energy storage system. When the sum of the real-time photovoltaic power generation and the real-time wind power generation is greater than the charging power demand, the photovoltaic array and the wind turbine supply power to the power distributor while also charging the energy storage system; when the sum of the real-time photovoltaic power generation and the real-time wind power generation is less than the charging power demand, but the sum of the real-time photovoltaic power generation, the real-time wind power generation and the discharge power of the energy storage system is greater than or equal to the charging power demand, the photovoltaic array, the wind turbine and the energy storage system supply power to the power distributor at the same time; when the sum of the real-time photovoltaic power generation, the real-time wind power generation and the discharge power of the energy storage system is less than the charging power demand, the photovoltaic array, the wind turbine, the energy storage system and the transformer supply power to the power distributor at the same time.

[0007] On the other hand, the embodiment of the present application also provides a wind-solar-storage vehicle charging control method, including obtaining the charging power demand of the charging gun, the real-time photovoltaic power generation of the photovoltaic array, the real-time wind power generation of the wind turbine, and the real-time remaining power of the energy storage system; When the sum of the real-time photovoltaic power generation and the real-time wind power generation is greater than the charging power demand, the photovoltaic array and the wind turbine generator supply power to the power distributor while also charging the energy storage system; When the sum of the real-time photovoltaic power generation and the real-time wind power generation is less than the charging power demand, but the sum of the real-time photovoltaic power generation, the real-time wind power generation and the discharge power of the energy storage system is greater than or equal to the charging power demand, the photovoltaic array, the wind turbine and the energy storage system simultaneously supply power to the power distributor; When the sum of the real-time photovoltaic power generation power, the real-time wind power generation power and the discharge power of the energy storage system is less than the charging power demand, the photovoltaic array, the wind turbine, the energy storage system and the transformer simultaneously supply power to the power distributor.

[0008] A wind-solar-storage vehicle charging system and control method in this application has the following advantages: By adding photovoltaic arrays and wind turbines to the energy storage system, the capacity of the energy storage system can be reduced, thereby reducing the high cost caused by using a large-capacity energy storage system. In addition, photovoltaic arrays and wind turbines can use energy that was previously discarded to charge the energy storage system, thereby improving the utilization rate of the energy storage system, invisibly increasing the capacity of the energy storage system, and significantly improving the effect of suppressing grid fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 A schematic diagram of the composition of a wind-solar-storage vehicle charging system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0012] Figure 1 A schematic diagram of the composition of a wind-solar-storage vehicle charging system provided in an embodiment of the present application. The embodiment of the present application provides a wind-solar-storage vehicle charging system, comprising a transformer, a first AC / DC converter, an energy storage system, a first DC / DC converter and a charging gun electrically connected in sequence, and also comprising a photovoltaic array, a second DC / DC converter, a wind turbine, a second AC / DC converter and a power distributor, wherein the photovoltaic array, the second DC / DC converter and the energy storage system are electrically connected in sequence, the wind turbine, the second AC / DC converter and the energy storage system are electrically connected in sequence, the power distributor is electrically connected between the energy storage system and the first DC / DC converter, and the second DC / DC converter and the second AC / DC converter are electrically connected to the power distributor respectively; The power distributor obtains the charging power demand of the charging gun, the real-time photovoltaic power generation of the photovoltaic array, the real-time wind power generation of the wind turbine and the real-time remaining power of the energy storage system. When the sum of the real-time photovoltaic power generation and the real-time wind power generation is greater than the charging power demand, the photovoltaic array and the wind turbine supply power to the power distributor while also charging the energy storage system; when the sum of the real-time photovoltaic power generation and the real-time wind power generation is less than the charging power demand, but the sum of the real-time photovoltaic power generation, the real-time wind power generation and the discharge power of the energy storage system is greater than or equal to the charging power demand, the photovoltaic array, the wind turbine and the energy storage system supply power to the power distributor at the same time; when the sum of the real-time photovoltaic power generation, the real-time wind power generation and the discharge power of the energy storage system is less than the charging power demand, the photovoltaic array, the wind turbine, the energy storage system and the transformer supply power to the power distributor at the same time.

[0013] Exemplarily, the transformer in the embodiment of the present application is a 10KV transformer. After the power grid inputs 10KV AC power to the high-voltage side of the transformer, the transformer converts the 10KV AC power into a lower voltage, such as 380V AC power, and then inputs it from the low-voltage side to the first AC / DC converter. The first AC / DC converter converts the low-voltage AC power into DC power that matches the voltage of the energy storage system, such as 220V or 380V DC power, which will be used as a power source for charging the energy storage system.

[0014] In an embodiment of the present application, in addition to being electrically connected to the energy storage system to charge the energy storage system, the first AC / DC converter is also electrically connected to the power distributor to directly supply power to the power distributor when the charging power demand is large.

[0015] The energy storage system includes energy storage batteries and a power management module. The power connected to the energy storage system is first processed by the power management module to allocate appropriate charging current and charging voltage to each energy storage battery, so that each energy storage battery is charged evenly to avoid overcharging of the energy storage battery. The discharge of the energy storage battery is also controlled by the power management module, so that each energy storage battery is discharged evenly to avoid over-discharge of the energy storage battery.

[0016] The first DC / DC converter steps up or steps down the voltage output by the power distributor and then provides it to the charging gun, which eventually charges the power battery of the electric vehicle. Since the demand for charging voltage of the power battery of the electric vehicle changes during the charging process, in the early stage of charging, the charging power is large, so the charging voltage is also relatively high. At this time, the charging voltage may exceed the voltage output by the energy storage system. Therefore, the first DC / DC converter needs to step up the voltage output by the energy storage system to meet the needs of the power battery. At the end of charging, the charging power will be significantly reduced, so the charging voltage will also be reduced. At this time, the charging voltage will definitely be lower than the voltage output by the energy storage system. Therefore, the first DC / DC converter needs to step down the voltage output by the energy storage system.

[0017] The second DC / DC converter is used to step down the thousands of volts of direct current output by the photovoltaic array to form 220V or 380V direct current to charge the energy storage system. The second AC / DC converter is used to rectify the alternating current output by the wind turbine to form 220V or 380V direct current to charge the energy storage system.

[0018] In the process of charging the power battery, the priority of selecting charging equipment is from high to low: photovoltaic array, wind turbine, energy storage system and power grid. The photovoltaic array and wind turbine have the same priority, while the power grid is powered by a transformer. With this priority selection method, it can ensure that new energy is used first, followed by the energy storage system, and finally the power grid, maximizing the use of energy generated by new energy. Using the energy storage system with appropriate frequency and intensity can take into account the utilization rate and service life of the energy storage system. The power grid is used as little as possible during the peak charging period, reducing the fluctuation of the power grid.

[0019] In a possible embodiment, when the charging power demand is zero and the energy storage system is not fully charged, the photovoltaic array and the wind turbine generator charge the energy storage system.

[0020] Exemplarily, the power distributor can monitor the access status of each charging gun. When a charging gun is connected to the power battery, the SOC (system on chip) voltage of the power battery will be obtained through the communication line on the charging gun, and the appropriate charging voltage and charging current will be determined according to the SOC voltage. Generally speaking, the charging process of the power battery is fast at first and then slow. In the early stage of charging, the SOC voltage of the power battery is low, and the charging power can be very high. In the later stage of charging, the SOC voltage of the power battery is close to the rated voltage, and the charging power at this time will be greatly reduced. If the charging gun is connected to the power battery outside the peak charging period, such as 1 pm to 5 pm, the charging power demand will be very small at this time, but the output power of the photovoltaic array and the wind turbine will be relatively high. At this time, the output power of the photovoltaic array and the wind turbine can fully meet the charging demand of the power battery. In addition to charging the power battery, the output power of the photovoltaic array and the wind turbine is still in surplus. If the energy storage system is not fully charged at this time, the photovoltaic array and the wind turbine will charge the energy storage system while supplying power to the power distributor to maximize the use of new energy.

[0021] In a possible embodiment, a DC / AC (direct current / alternating current) inverter is also included. The DC / AC inverter is electrically connected between the photovoltaic array and the transformer. The wind turbine is also electrically connected to the transformer. When the charging power demand is zero and the energy storage system is fully charged, the photovoltaic array and the wind turbine supply power to the grid through the transformer.

[0022] Exemplarily, the DC / AC inverter is used to invert and step down the high-voltage direct current output by the photovoltaic array and then input it into the low-voltage side of the transformer. At the same time, the alternating current output by the wind turbine will also be input into the low-voltage side of the transformer. After being stepped up by the transformer, the 10KV alternating current will be transmitted to the power grid to supplement the demand of the power grid when there is a surplus in the output power of the photovoltaic array and the wind turbine.

[0023] If any charging gun is not connected to the power battery and the energy storage system is fully charged, the electricity generated by the photovoltaic array and wind turbine will no longer be used to charge the power battery and the energy storage system. At this time, in order to avoid energy waste, the electricity generated by the photovoltaic array and wind turbine will be transmitted to the power grid through the transformer to supply power to other devices through the power grid.

[0024] Furthermore, when the charging power demand is not zero, but the sum of the real-time photovoltaic power generation and the real-time wind power generation is greater than the charging power demand, and the energy storage system is fully charged, the photovoltaic array and the wind turbine generator supply power to the grid through the transformer. At this time, the power output of the photovoltaic array and the wind turbine generator will not only charge the power battery, but also transmit the remaining power to the grid, realizing the maximum utilization of new energy.

[0025] Furthermore, when the charging power demand is not zero, but the sum of the real-time photovoltaic power generation power and the real-time wind power generation power is greater than the sum of the charging power and the charging power demand of the energy storage system, and the energy storage system is not fully charged, the photovoltaic array and the wind turbine generator supply power to the energy storage system and the power distributor, and also supply power to the grid through the transformer.

[0026] In a possible embodiment, when the energy storage system is not fully charged and the current time is within a set time period, the transformer charges the energy storage system.

[0027] For example, the current electricity price implements a peak-valley system. Although the peak-valley time and price vary from place to place, the valley period is relatively low in terms of power grid load and electricity price compared to the peak period. The valley period is generally at night, when the photovoltaic array and wind turbine have almost no power output. Therefore, in order to raise the grid load during the valley period to reduce the peak-valley load difference on the one hand, and reduce the charging cost on the other hand, the embodiment of the present application also charges the energy storage system from the grid during the valley period. Of course, if the energy storage system is already full, the energy storage will no longer be charged. In the case where the photovoltaic array and wind turbine have almost no power output, if any one or more charging guns are connected to the power battery, the power distributor will give priority to using the electric energy in the energy storage system to charge the power battery. When the charging power demand of the power battery exceeds the discharge power of the energy storage system, it will be connected to the grid and the power battery will be charged by the grid. When charging the power battery using the grid, it is also determined whether the current time is in the set time period, that is, the valley period. If it is, the grid will also charge the energy storage system. If not, the grid will only charge the power battery.

[0028] In a possible embodiment, a first DC / DC converter and a charging gun are electrically connected to form a charging pile, and multiple charging piles are electrically connected to a power distributor respectively. The charging modes of the power distributor include first-come first and average distribution. In the first-come first charging mode, the power distributor distributes the vehicle charging power according to the time sequence of the charging guns connected to the electric vehicle. The earlier the charging gun is connected to the electric vehicle, the higher the vehicle charging power. In the average distribution charging mode, the power distributor evenly distributes the vehicle charging power to each charging gun according to the charging power demand.

[0029] Exemplarily, the above two charging modes can be manually set by the staff on the power distributor, or they can be automatically switched by the power distributor. When the power distributor automatically switches, the power distributor can monitor the number of connected charging guns in real time. If the number of charging guns connected to the power battery reaches or exceeds a certain proportion of the total number of charging guns, such as 80%, it can be switched to the average distribution mode to take care of the charging needs of all electric vehicles during the peak charging period. When the number of charging guns connected to the power battery is lower than the above proportion of the total number of charging guns, the charging mode will remain in the first-come-first-served mode to increase the charging speed of the vehicles that are charged first.

[0030] It should be understood that in the average distribution charging mode, the average distribution of the car charging power to each charging gun does not require that the car charging power of each electric vehicle is the same, but that the charging power of the electric vehicle is the same under the same charging stage. Generally, the charging process of the power battery includes at least constant current charging and constant voltage charging. In the constant current charging stage, the power battery will be charged with a constant current. At this time, the charging power is high, and the power of the power battery will be quickly charged to a certain proportion, such as 80%. Once the proportion is reached, it will be transferred to the constant voltage charging stage. In the constant voltage charging stage, the power battery will be charged with a constant voltage, and the charging current will gradually decrease until the power battery is full. It can be seen that different charging stages have different requirements for charging power. Therefore, the power distributor of the present application can determine the corresponding charging stage after obtaining the SOC voltage of each power battery, and then control the power batteries in the same charging stage to the same charging power.

[0031] In a possible embodiment, the transformer, the first AC / DC converter, the energy storage system, the first DC / DC converter, the charging gun, the photovoltaic array, the second DC / DC converter, the wind turbine, the second AC / DC converter and the power distributor are all arranged on the same skid-mounted top plate.

[0032] For example, in some temporary sites, such as mines and temporary construction sites, there are often no conditions for installing permanent charging piles. Therefore, this application uses a skid-mounted method to set up multiple charging piles in areas where charging is required. The equipment required for charging can be pre-installed on the skid-mounted top plate. When necessary, the skid-mounted top plate together with the equipment on it can be transported and hoisted to the charging site. After the transformer is connected to the power grid and the relevant equipment is assembled, it can be used normally. This method greatly reduces the construction period and reduces the requirements for the site, which is very suitable for charging in temporary sites.

[0033] In an embodiment of the present application, in order to further improve the mobility of the charging system, the skid-mounted top plate can be fixed on a mobile platform, which can be built based on the vehicle chassis so that the entire charging system can be moved quickly with the support of mobile components such as wheels, without relying on lifting equipment.

[0034] Furthermore, the photovoltaic array in the embodiment of the present application occupies a large area, while the wind turbine is relatively high. During transportation, the relevant components of the photovoltaic array and the wind turbine can be disassembled and transported separately. After arriving at the charging area and completing the installation of the skid-mounted top plate, the photovoltaic array and the wind turbine can be assembled on the skid-mounted top plate.

[0035] The present application also provides a method for controlling charging of a wind-solar-storage vehicle, the method comprising the following steps: Obtain the charging power demand of the charging gun, the real-time photovoltaic power generation of the photovoltaic array, the real-time wind power generation of the wind turbine, and the real-time remaining power of the energy storage system; When the sum of the real-time photovoltaic power generation and the real-time wind power generation is greater than the charging power demand, the photovoltaic array and the wind turbine generator supply power to the power distributor while also charging the energy storage system; When the sum of the real-time photovoltaic power generation and the real-time wind power generation is less than the charging power demand, but the sum of the real-time photovoltaic power generation, the real-time wind power generation and the discharge power of the energy storage system is greater than or equal to the charging power demand, the photovoltaic array, the wind turbine and the energy storage system simultaneously supply power to the power distributor; When the sum of the real-time photovoltaic power generation power, the real-time wind power generation power and the discharge power of the energy storage system is less than the charging power demand, the photovoltaic array, the wind turbine, the energy storage system and the transformer simultaneously supply power to the power distributor.

[0036] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0037] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A wind-solar-storage vehicle charging system, comprising a transformer, a first AC / DC converter, an energy storage system, a first DC / DC converter and a charging gun electrically connected in sequence, characterized in that: It also includes a photovoltaic array, a second DC / DC converter, a wind turbine, a second AC / DC converter and a power distributor, wherein the photovoltaic array, the second DC / DC converter and the energy storage system are electrically connected in sequence, the wind turbine, the second AC / DC converter and the energy storage system are electrically connected in sequence, the power distributor is electrically connected between the energy storage system and the first DC / DC converter, and the second DC / DC converter and the second AC / DC converter are electrically connected to the power distributor respectively; The power distributor obtains the charging power demand of the charging gun, the real-time photovoltaic power generation power of the photovoltaic array, the real-time wind power generation power of the wind turbine and the real-time remaining power of the energy storage system. When the sum of the real-time photovoltaic power generation power and the real-time wind power generation power is greater than the charging power demand, the photovoltaic array and the wind turbine charge the energy storage system while supplying power to the power distributor; when the sum of the real-time photovoltaic power generation power and the real-time wind power generation power is less than the charging power demand, but the sum of the real-time photovoltaic power generation power, the real-time wind power generation power and the discharge power of the energy storage system is greater than or equal to the charging power demand, the photovoltaic array, the wind turbine and the energy storage system supply power to the power distributor at the same time; when the sum of the real-time photovoltaic power generation power, the real-time wind power generation power and the discharge power of the energy storage system is less than the charging power demand, the photovoltaic array, the wind turbine, the energy storage system and the transformer supply power to the power distributor at the same time.

2. A wind-solar-storage vehicle charging system according to claim 1, characterized in that: When the charging power demand is zero and the energy storage system is not fully charged, the photovoltaic array and the wind turbine charge the energy storage system.

3. A wind-solar-storage vehicle charging system according to claim 2, characterized in that: It also includes a DC / AC inverter, which is electrically connected between the photovoltaic array and the transformer. The wind generator is also electrically connected to the transformer. When the charging power demand is zero and the energy storage system is fully charged, the photovoltaic array and the wind generator supply power to the power grid through the transformer.

4. A wind-solar-storage vehicle charging system according to claim 3, characterized in that: When the charging power demand is not zero, but the sum of the real-time photovoltaic power generation power and the real-time wind power generation power is greater than the charging power demand, and the energy storage system is fully charged, the photovoltaic array and the wind generator supply power to the grid through the transformer.

5. The wind-solar-storage vehicle charging system according to claim 3 is characterized in that: When the charging power demand is not zero, but the sum of the real-time photovoltaic power generation power and the real-time wind power generation power is greater than the sum of the charging power of the energy storage system and the charging power demand, and the energy storage system is not fully charged, the photovoltaic array and the wind generator supply power to the energy storage system and the power distributor, and also supply power to the grid through the transformer.

6. The wind-solar-storage vehicle charging system according to claim 1 is characterized in that: When the energy storage system is not fully charged and the current time is within a set time period, the transformer charges the energy storage system.

7. The wind-solar-storage vehicle charging system according to claim 1 is characterized in that: A first DC / DC converter and a charging gun are electrically connected to form a charging pile, and multiple charging piles are electrically connected to the power distributor respectively. The charging mode of the power distributor includes first-come-first-served. In the first-come-first-served charging mode, the power distributor distributes the vehicle charging power according to the time sequence of the charging guns connected to the electric vehicle. The earlier the charging gun is connected to the electric vehicle, the higher the vehicle charging power.

8. A wind-solar-storage vehicle charging system according to claim 7, characterized in that: The charging mode of the power distributor also includes average distribution. In the average distribution charging mode, the power distributor evenly distributes the vehicle charging power to each charging gun according to the charging power demand.

9. The wind-solar-storage vehicle charging system according to claim 1 is characterized in that: The transformer, the first AC / DC converter, the energy storage system, the first DC / DC converter, the charging gun, the photovoltaic array, the second DC / DC converter, the wind turbine, the second AC / DC converter and the power distributor are all arranged on the same skid-mounted top plate.

10. A control method for a wind-solar-storage vehicle charging system as claimed in any one of claims 1 to 9, characterized in that: include: Obtain the charging power demand of the charging gun, the real-time photovoltaic power generation of the photovoltaic array, the real-time wind power generation of the wind turbine, and the real-time remaining power of the energy storage system; When the sum of the real-time photovoltaic power generation power and the real-time wind power generation power is greater than the charging power requirement, the photovoltaic array and the wind generator supply power to the power distributor while also charging the energy storage system; When the sum of the real-time photovoltaic power generation power and the real-time wind power generation power is less than the charging power requirement, but the sum of the real-time photovoltaic power generation power, the real-time wind power generation power and the discharge power of the energy storage system is greater than or equal to the charging power requirement, the photovoltaic array, the wind generator and the energy storage system simultaneously supply power to the power distributor; When the sum of the real-time photovoltaic power generation power, the real-time wind power generation power and the discharge power of the energy storage system is less than the charging power requirement, the photovoltaic array, the wind generator, the energy storage system and the transformer simultaneously supply power to the power distributor.

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