Energy scheduling optimization method and system for optical storage and charging system

Abstract

The invention discloses an energy scheduling optimization method and system for an optical storage and charging system, and the method comprises the steps: obtaining the output power PPV of a photovoltaic system and the power Pload of a charging pile in the optical storage and charging system, and controlling a photovoltaic system and an energy storage system to work according to a comparison result of the output power PPV of the photovoltaic system and the power Pload of the charging pile; the system comprises relevant parameters of a degree layer, an execution layer and a scheduling layer, a control instruction is generated and transmitted to the execution layer, the execution layer comprises a power distribution controller, a first tracking controller, a second tracking controller and a third tracking controller, and the execution layer executes the energy scheduling optimization method according to the control instruction. According to the invention, the photovoltaic output power can be fully utilized, the bus voltage is maintained to be close to a rated value, and the flexibility of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of energy scheduling methods for photovoltaic storage and charging systems, and in particular to an energy scheduling optimization method and system for photovoltaic storage and charging systems. Background Art

[0002] The photovoltaic storage and charging system combines distributed photovoltaic, energy storage system, fast charging pile and other advanced technologies to achieve the organic combination of source, storage and load. The photovoltaic storage and charging energy scheduling optimization strategy mainly focuses on the integration and optimization of photovoltaic power generation system (photovoltaic), energy storage system (storage) and charging pile system (charging) in the photovoltaic storage and charging system. With the popularization of renewable energy and the rapid development of electric vehicles, how to efficiently utilize solar energy resources, energy storage systems and electric vehicle charging networks has become an important challenge in energy management.

[0003] The existing optimization strategies for solar-storage-charging energy scheduling mainly include optimization strategies based on heuristic algorithms, optimization strategies based on model predictive control (MPC), and optimization strategies based on game theory. Although domestic and foreign scholars have done a lot of work on the energy management and control of independent solar-storage systems and achieved many results, the power optimization allocation and energy management control of the hybrid energy storage modular integrated architecture need further research. More innovative research methods and a lot of meticulous work are needed to improve the flexibility and stability, which will help the vigorous development and large-scale application of solar-storage power generation systems. Summary of the invention

[0004] The present invention provides a method and system for optimizing energy scheduling of a photovoltaic storage and charging system, so as to solve the problems of poor flexibility and stability in the energy scheduling method of the photovoltaic storage and charging system in the prior art.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The energy scheduling optimization method of the photovoltaic storage and charging system includes a photovoltaic system, an energy storage system, and a charging pile system, wherein the electric energy generated by the photovoltaic system is output to the charging pile system through a DC bus power supply, and if there is surplus electric energy, the surplus electric energy is output to the energy storage system through the DC bus for storage, and the energy storage system can supply power to the charging pile system through the DC bus, comprising the following steps:

[0007] Step 1: Obtain the output power P of the photovoltaic system in the solar storage and charging system PV 、Power P of the charging pile load ;

[0008] Step 2: Compare the photovoltaic system output power P obtained in step 1 PV 、Power P of the charging pile load, and control the operation of the solar storage and charging system according to the comparison results. The process is as follows:

[0009] When the photovoltaic system output power P PV = Power of charging pile P load When the power is on, the photovoltaic system is controlled to operate in a constant voltage output state to supply power to the charging pile system, and the energy storage system is not operated;

[0010] When the photovoltaic system output power P PV ﹥Charging pile power P load If not all energy storage modules in the energy storage system exceed the limit, the remaining rechargeable capacity of each energy storage module is determined one by one to determine whether it exceeds the limit. If there is an energy storage module with a remaining rechargeable capacity exceeding the limit, the energy storage module with the remaining rechargeable capacity exceeding the limit is turned off, so that the energy storage system that has not exceeded the limit is charged normally, and the energy storage module that exceeds the limit is turned off and not charged, and the photovoltaic system is controlled to work in MPPT mode;

[0011] When the photovoltaic system output power P PV ﹥Charging pile power P load When each energy storage module in the energy storage system exceeds the time limit, all energy storage modules in the energy storage system are controlled to be shut down, and the photovoltaic system is operated in a constant voltage output state;

[0012] When the photovoltaic system output power P PV ﹤Charging pile power P load If not all energy storage modules in the energy storage system exceed the limit, the remaining dischargeable capacity of each energy storage module is determined one by one to determine whether it exceeds the limit. If there is an energy storage module with a remaining dischargeable capacity exceeding the limit, the energy storage module with the remaining dischargeable capacity exceeding the limit is turned off, and the energy storage modules in the energy storage system that have not exceeded the limit are controlled to switch to the discharge mode to supply power to the charging pile system. The energy storage modules that have exceeded the limit are not charged, and the photovoltaic system is controlled to work in the MPPT mode to discharge to the energy storage modules in the energy storage system that have not exceeded the limit.

[0013] When the photovoltaic system output power P PV ﹤Charging pile power P load And when each energy storage module in the energy storage system exceeds the time limit, the DC bus voltage is stabilized.

[0014] In a further step 2, when the photovoltaic system output power P PV = Power of charging pile P load When the power required by the charging pile system is fully provided by the photovoltaic system.

[0015] In a further step 2, when the photovoltaic system output power P PV ﹤Charging pile power P loadWhen each energy storage module in the energy storage system exceeds the limit, some charging piles in the charging pile system are controlled to disconnect from the DC bus to stabilize the DC bus voltage.

[0016] A system for optimizing energy scheduling of a photovoltaic storage and charging system comprises a scheduling layer and an execution layer, wherein the scheduling layer obtains photovoltaic power parameters, charging pile demand parameters, and energy storage operation status parameters in the photovoltaic storage and charging system, and generates control instructions to transmit to the execution layer; the execution layer executes steps 1 to 2 of the above-mentioned method for optimizing energy scheduling of a photovoltaic storage and charging system according to the control instructions.

[0017] Furthermore, the execution layer includes a power distribution controller, a first tracking controller, a second tracking controller, and a third tracking controller; the scheduling layer transmits control instructions to the power distribution controller, and the power distribution controller controls the operation of the electrically connected first tracking controller, the second tracking controller, and the third tracking controller respectively, wherein the first tracking controller controls the photovoltaic system in the electrically connected photo-storage-charging system, the second tracking controller controls the energy storage system in the electrically connected photo-storage-charging system, and the third tracking controller controls the charging pile system in the electrically connected photo-storage-charging system.

[0018] The present invention rationally divides the photovoltaic storage and charging system into multiple working modes according to the different states of the photovoltaic system (PV), the energy storage system and the charging pile system, makes fuller use of the photovoltaic output power, maintains the bus voltage near the rated value, improves the flexibility of the system, and is a control strategy that can prevent overcharging / overdischarging of energy storage and provide energy based on the remaining capacity of the energy storage module, effectively improving the stability of the operation of the photovoltaic storage and charging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an embodiment of the present invention.

[0020] Figure 2 This is an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0022] like Figure 1As shown, this embodiment discloses an energy scheduling optimization system for a photoelectric storage and charging system, wherein the photoelectric storage and charging system includes a photovoltaic system, an energy storage system, and a charging pile system, wherein the electric energy generated by the photovoltaic system is output to the charging pile system through a DC bus power supply, and if there is surplus electric energy, the surplus electric energy is output to the energy storage system through the DC bus for storage, and the energy storage system can supply power to the charging pile system through the DC bus. This embodiment of a photoelectric storage and charging system energy scheduling optimization system includes a scheduling layer EMS, and an execution layer. The scheduling layer EMS is used for the optimization strategy to generate a total energy storage power instruction by comprehensively analyzing the operating status of the system, the demand for charging piles, and the energy storage capacity; the execution layer allocation module is responsible for receiving these allocation instructions, and further refining the power allocation to ensure that each energy storage element can achieve accurate power allocation under specific conditions.

[0023] Specifically, the dispatching layer EMS collects photovoltaic power parameters, charging pile demand parameters, and energy storage operation status parameters, and generates control instructions to transmit to the execution layer. The execution layer includes a power distribution controller PTC, a first tracking controller T C1 , the second tracking controller T C2 , the third tracking controller T C3 The dispatching layer EMS transmits control instructions to the power distribution controller PTC, and the power distribution controller PTC controls the first tracking controller T C1 , the second tracking controller T C2 、The third tracking controller works T C3 , where the first tracking controller T C1 Control the photovoltaic system in the electrical connection light storage charging system, the second tracking controller T C2 Control the energy storage system in the electrically connected light storage charging system, the third tracking controller T C3 Control the charging pile system in the electrical connection photovoltaic storage and charging system.

[0024] In the execution layer, the power distribution controller PTC is responsible for optimizing the distribution according to the control instructions to ensure that each energy storage unit achieves the optimal power distribution within its operating constraints. C1 , T C2 , T C3 The received power instructions will be accurately executed to achieve power tracking of the energy storage unit. The dispatching layer EMS monitors the changes in photovoltaic power and the dynamic needs of charging piles in real time, adjusts the control instructions, and makes the power flow between the photovoltaic system, energy storage system and charging pile system reach the optimal state, thereby improving the efficiency and stability of the entire photovoltaic storage and charging system.

[0025] like Figure 2As shown, this embodiment discloses a method for optimizing energy scheduling of a photovoltaic storage and charging system implemented by an energy scheduling optimization system for a photovoltaic storage and charging system. On the basis of ensuring instantaneous power balance, the method of this embodiment takes into account the remaining chargeable / dischargeable capacity of each energy storage module in the energy storage (SIBs) system, and divides the system into multiple working modes according to the different states of the photovoltaic (PV) system, the energy storage (SIBs) system, and the charging pile system, and controls each system to be in different states in different modes, so as to make fuller use of the photovoltaic output and maintain the stability of the DC bus voltage. By reasonably dividing the photovoltaic storage and charging system into multiple working modes and performing different controls on different modes, the stable switching and operation of the system in different modes are guaranteed. A method for optimizing energy scheduling of a photovoltaic storage and charging system in this embodiment includes the following steps:

[0026] Step 1: Obtain the output power P of the photovoltaic system in the solar storage and charging system PV , load, i.e. the power of the charging pile P load ;

[0027] Step 2: Compare the photovoltaic system output power P obtained in step 1 PV 、Power P of the charging pile load , and control the operation of the solar storage and charging system according to the comparison results. The process is as follows:

[0028] When the photovoltaic system output power P PV = Power of charging pile P load When the power required by the charging pile system is fully provided by the photovoltaic system, the energy storage (SIBs) system is controlled not to work, and the photovoltaic (PV) system is controlled to work in a constant voltage output state to supply power to the charging pile system, so as to make reasonable use of the photovoltaic system.

[0029] When the photovoltaic system output power P PV ﹥Charging pile power P load If not all energy storage modules in the energy storage system exceed the limit, the remaining rechargeable capacity of each energy storage module is determined one by one to see if it exceeds the limit. If there are energy storage modules with a remaining rechargeable capacity exceeding the limit, it means that the remaining rechargeable capacity of these energy storage modules is 0 and cannot be charged further. Then, the energy storage modules with a remaining rechargeable capacity exceeding the limit are turned off, so that the energy storage systems that have not exceeded the limit are charged normally, and the energy storage modules that have exceeded the limit are turned off and not charged, and the photovoltaic system is controlled to work in MPPT mode to maximize the utilization of the photovoltaic system.

[0030] When the photovoltaic system output power P PV ﹥Charging pile power P loadMoreover, when each energy storage module in the energy storage system exceeds the limit, it indicates that each energy storage module is overcharged, and continued charging will have an adverse effect on the system. Therefore, all energy storage modules in the energy storage system are controlled to be shut down, and the photovoltaic system is operated in a constant voltage output state to ensure the stable operation of the light storage and charging system.

[0031] When the photovoltaic system output power P PV ﹤Charging pile power P load If not all energy storage modules in the energy storage system exceed the limit, the remaining dischargeable capacity of each energy storage module is determined one by one to determine whether it exceeds the limit. If there is an energy storage module with a remaining dischargeable capacity exceeding the limit, it means that the remaining dischargeable capacity of the energy storage module is 0 and cannot continue to discharge, so the energy storage module with the remaining dischargeable capacity exceeding the limit is turned off. At this time, the output power of the photovoltaic system is less than the demand of the charging pile system, so the energy storage modules that have not exceeded the limit in the energy storage system are controlled to switch to the discharge mode to supply power to the charging pile system, and the energy storage modules that have exceeded the limit are not charged, and the photovoltaic system is controlled to work in the MPPT mode to discharge the energy storage modules that have not exceeded the limit in the energy storage system.

[0032] When the photovoltaic system output power P PV ﹤Charging pile power P load When each energy storage module in the energy storage system exceeds the limit, the energy storage system will be over-discharged. If the discharge continues, it will have an adverse effect on the photovoltaic storage and charging system. At this time, the charging pile system will stabilize the DC bus voltage by discarding some secondary charging piles in the charging pile system (that is, some secondary charging piles are disconnected from the DC bus) to stabilize the DC bus voltage near the rated voltage.

[0033] The power relationship between the various parts of the photovoltaic storage and charging system is shown in formula (1).

[0034]

[0035] Where P DC is the power of the DC bus; E DC is the energy change of the DC bus; T is the operation time of the system; P SIBS is the power of the energy storage unit, that is, the power of the sodium ion battery; P PV is the photovoltaic power; Pl oad is the power of the charging pile.

[0036] When the voltage changes, the energy change generated by the DC bus is mainly caused by the capacitor, and the calculation formula is shown in formula (2).

[0037]

[0038] In the formula, C DC is the DC bus capacitance; U DC is the DC bus voltage; U′DC is the rated voltage of the DC bus.

[0039] From formula 2, we can see that the power change of each system will cause the DC bus voltage to fluctuate. From formulas (1) and (2), we can see that the power change of each unit will cause the DC bus voltage to fluctuate. In this way, the system can be reasonably divided into multiple working modes and different modes can be controlled differently to ensure the stable switching and operation of the system in different modes.

[0040] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. The embodiments described in the present invention are merely descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. The various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction, and such combinations should also be regarded as the contents disclosed in the present disclosure as long as they do not violate the concept of the present invention. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0041] The present invention is not limited to the specific details of the above-mentioned embodiments. Within the technical concept of the present invention and without departing from the design concept of the present invention, various modifications and improvements made to the technical solution of the present invention by technical personnel in this field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the claims.

Claims

1. A method for optimizing energy scheduling of a photovoltaic storage and charging system, wherein the photovoltaic storage and charging system includes a photovoltaic system, an energy storage system, and a charging pile system, wherein the electric energy generated by the photovoltaic system is output to the charging pile system through a DC bus, and if there is surplus electric energy, the surplus electric energy is output to the energy storage system through the DC bus for storage, and the energy storage system can supply power to the charging pile system through the DC bus, characterized in that: The following steps are involved: Step 1: Obtain the output power of the photovoltaic system in the solar storage and charging system P PV , the power of the charging pile P load ; Step 2: Compare the PV system output power obtained in step 1 P PV , the power of the charging pile P load , and control the operation of the solar storage and charging system according to the comparison results. The process is as follows: When the photovoltaic system output power P PV =Power of the charging station P load When the power is on, the photovoltaic system is controlled to operate in a constant voltage output state to supply power to the charging pile system, and the energy storage system is not operated; When the photovoltaic system output power P PV ﹥Power of charging pile P load If not all energy storage modules in the energy storage system exceed the limit, the remaining rechargeable capacity of each energy storage module is determined one by one to determine whether it exceeds the limit. If there is an energy storage module with a remaining rechargeable capacity exceeding the limit, the energy storage module with the remaining rechargeable capacity exceeding the limit is turned off, so that the energy storage system that has not exceeded the limit is charged normally, and the energy storage module that exceeds the limit is turned off and not charged, and the photovoltaic system is controlled to work in MPPT mode; When the photovoltaic system output power P PV ﹥Power of charging pile P load When each energy storage module in the energy storage system exceeds the time limit, all energy storage modules in the energy storage system are controlled to be shut down, and the photovoltaic system is operated in a constant voltage output state; When the photovoltaic system output power P PV ﹤Power of charging pile P load If not all energy storage modules in the energy storage system exceed the limit, the remaining dischargeable capacity of each energy storage module is determined one by one to determine whether it exceeds the limit. If there is an energy storage module with a remaining dischargeable capacity exceeding the limit, the energy storage module with the remaining dischargeable capacity exceeding the limit is turned off, and the energy storage modules in the energy storage system that have not exceeded the limit are controlled to switch to the discharge mode to supply power to the charging pile system. The energy storage modules that have exceeded the limit are not charged, and the photovoltaic system is controlled to work in the MPPT mode to discharge to the energy storage modules in the energy storage system that have not exceeded the limit. When the photovoltaic system output power P PV ﹤Power of charging pile P load And when each energy storage module in the energy storage system exceeds the time limit, the DC bus voltage is stabilized.

2. The method for optimizing energy scheduling of a photovoltaic storage and charging system according to claim 1, characterized in that: In step 2, when the photovoltaic system output power P PV =Power of the charging station P load When the power required by the charging pile system is fully provided by the photovoltaic system.

3. The method for optimizing energy scheduling of a photovoltaic storage and charging system according to claim 2, characterized in that: In step 2, when the photovoltaic system output power P PV ﹤Power of charging pile P load When each energy storage module in the energy storage system exceeds the limit, some charging piles in the charging pile system are controlled to disconnect from the DC bus to stabilize the DC bus voltage.

4. An energy scheduling optimization system for a photovoltaic storage and charging system, characterized in that: It includes a scheduling layer and an execution layer, wherein the scheduling layer obtains photovoltaic power parameters, charging pile demand parameters, and energy storage operation status parameters in the photovoltaic storage and charging system, and generates control instructions to transmit to the execution layer; the execution layer executes steps 1-2 of the photovoltaic storage and charging system energy scheduling optimization method as described in any one of claims 1-3 according to the control instructions.

5. The energy scheduling optimization system of a photovoltaic storage and charging system according to claim 4 is characterized in that: The execution layer includes a power distribution controller, a first tracking controller, a second tracking controller, and a third tracking controller; the scheduling layer transmits control instructions to the power distribution controller, and the power distribution controller controls the operation of the electrically connected first tracking controller, the second tracking controller, and the third tracking controller respectively, wherein the first tracking controller controls the photovoltaic system in the electrically connected photo-storage-charging system, the second tracking controller controls the energy storage system in the electrically connected photo-storage-charging system, and the third tracking controller controls the charging pile system in the electrically connected photo-storage-charging system.

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