A method for reducing power consumption of a common direct current bus energy storage system and a terminal

Abstract

The application discloses a kind of co-direct current bus energy storage systems power consumption reduction method and terminal, comprising: judging whether the output power of each area exists AC power generation system is insufficient to support the load in the area, if yes, dispatch redundant area to compensate insufficient area, and start the least sub-energy storage system required to maintain, absorb or compensate direct current bus;If there is area in heavy load state, mobilize the grid of light load area to compensate area in heavy load state, and only start the energy storage subsystem of one area to maintain direct current bus;If the output power of power grid is greater than the set multiple of power grid rated output power, then the least energy storage subsystem of area is used to compensate the output power of power grid.It can be seen that it uses as few energy storage subsystems as possible to maintain, compensate and absorb direct current bus, thereby reducing the power consumption of shared direct current bus energy storage system to maintain direct current bus without affecting the operation of energy storage system strategy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage systems, in particular to a method for reducing power consumption of a common DC bus energy storage system and a terminal. BACKGROUND

[0002] The shared DC bus energy storage system is composed of two or more energy storage subsystems, each of which is composed of one cabinet, one DC / DC, one PCS and an EMS system. The DC bus voltage of a single energy storage subsystem is established by the DC / DC boost, and the DC bus voltage is maintained by the droop control strategy. The DC buses of all energy storage subsystems are connected in parallel on the same DC bus, and the energy scheduling of the energy storage subsystem is controlled by the EMS. The shared DC bus energy storage system has a total control terminal, which can communicate with all EMSs of the energy storage subsystems and issue instructions.

[0003] However, the DC bus voltage of the shared DC bus energy storage system is maintained by the DC / DC through the droop control strategy, and the cabinet needs to output energy to maintain the DC bus, which causes the cabinet to continuously discharge even when the energy storage system is on standby, resulting in high power consumption of the common DC bus energy storage system. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method for reducing power consumption of a common DC bus energy storage system and a terminal to reduce the operating power of the common DC bus energy storage system.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] S1, determining whether the AC power generation system outputs power, if yes, executing step S2, otherwise executing step S3;

[0007] S2, determining whether the output power of the AC power generation system in each area is insufficient to support the load in the area, if yes, dispatching the area with redundancy to compensate for the insufficient area, and starting the least required sub-energy storage system to maintain, absorb or compensate the DC bus;

[0008] S3, determining whether there is an area in a heavy load state, if yes, mobilizing the power grid of the light load area to compensate for the area in the heavy load state, and starting only one energy storage subsystem of the area to maintain the DC bus; determining whether the output power of the power grid is greater than the first set multiple of the rated output power of the power grid, if yes, using the least required energy storage subsystem of the area to compensate for the output power of the power grid.

[0009] To solve the above technical problems, another technical scheme adopted by the present application is as follows:

[0010] A common DC bus energy storage system power reduction terminal, comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implements the following steps when executing the computer program:

[0011] S1, judging whether the AC power generation system outputs power, if yes, executing step S2, otherwise executing step S3;

[0012] S2, judging whether the output power of the AC power generation system is insufficient to support the load in each area, if yes, dispatching the area with redundancy to compensate for the insufficient area, and starting the least required sub-energy storage system to maintain, consume or compensate the DC bus;

[0013] S3, judging whether there is an area in a heavy load state, if yes, mobilizing the power grid of the light load area to compensate for the area in the heavy load state, and only starting the energy storage subsystem of one area to maintain the DC bus; judging whether the output power of the power grid is greater than the first set multiple of the rated output power of the power grid, if yes, using the least required energy storage subsystem of the area to compensate for the output power of the power grid.

[0014] The application has the beneficial effects that: a common DC bus energy storage system power reduction method uses as few energy storage subsystems as possible to maintain, compensate and consume the DC bus, thereby reducing the power consumption of the shared DC bus energy storage system for maintaining the DC bus without affecting the strategic operation of the energy storage system, improving the charge-discharge conversion efficiency of the system, and reducing the heavy load rate and load imbalance rate of the area. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a structure schematic diagram of the common DC bus energy storage system of the embodiment of the application;

[0016] Figure 2 It is a communication structure schematic diagram of the control terminal of the embodiment of the application;

[0017] Figure 3 It is a flow schematic diagram of a common DC bus energy storage system power reduction method of the embodiment of the application;

[0018] Figure 4 It is a structure schematic diagram of a common DC bus energy storage system power reduction terminal of the embodiment of the application.

[0019] REFERENCE NUMERALS:

[0020] 1. A common DC bus energy storage system power reduction terminal; 2. a processor; 3. a memory. DETAILED DESCRIPTION

[0021] In order to explain the technical content of the present application, the purposes and effects achieved, the following will be described in conjunction with the embodiments and the accompanying drawings.

[0022] Please refer to Figure 1 A power consumption reduction method of a common DC bus energy storage system, comprising the steps of:

[0023] S1, judging whether the AC power generation system outputs power, if yes, executing step S2, otherwise executing step S3;

[0024] S2, judging whether the output power of each substation is insufficient to support the load in the substation, if yes, dispatching the substations with redundancy to compensate for the insufficient substations, and starting the least required sub energy storage system to maintain, consume or compensate the DC bus;

[0025] S3, judging whether there is a substation in a heavy load state, if yes, mobilizing the power grid of the light load substation to compensate for the substation in the heavy load state, and starting only one substation energy storage system to maintain the DC bus; judging whether the output power of the power grid is greater than the first set multiple of the rated output power of the power grid, if yes, using the least required substation energy storage system to compensate for the output power of the power grid.

[0026] From the above description, the present application has the following advantages: a power consumption reduction method of a common DC bus energy storage system uses as few energy storage systems as possible to maintain, compensate and consume the DC bus, thereby reducing the power consumption of the shared DC bus energy storage system for maintaining the DC bus, improving the charge-discharge conversion efficiency of the system, and reducing the heavy load rate and load imbalance rate of the substation.

[0027] Further, the judgment of whether there is a substation in a heavy load state is specifically to judge whether the sum of the load power of half or less of the substations is twice or more than twice the sum of the load power of the remaining substations, if yes, judging that the substation whose sum of load power is twice or more than twice the sum of the load power of the remaining substations is in a heavy load state, and the remaining substations are in a light load state.

[0028] From the above description, the judgment of the heavy load and light load of each substation is realized.

[0029] Further, in step S3, the mobilization of the power grid of the light load substation to compensate for the substation in the heavy load state is specifically:

[0030] The substation in the heavy load state takes power from the DC bus;

[0031] The substation in the light load state inputs power P PCS = (P 重载 -P 非重载 ) / n to the DC bus;

[0032] P = P + P 重载 is the sum of the powers of the heavy-load area, P 非重载 is the sum of the powers of the light-load area, and n is the number of the light-load area;

[0033] The output power of the power grid is compensated by the energy storage subsystems that require the least number of substations, and the compensation includes:

[0034] The total power P 补偿 required to compensate the power grid is obtained.

[0035] It is determined whether the discharging power of the energy storage subsystem with the largest SOC value is greater than P 补偿 . If yes, the energy storage subsystem with the largest SOC value is controlled to maintain the DC bus and perform the compensation action until the energy storage subsystem is empty or the discharging power is less than P 补偿 , and the remaining energy storage subsystems with the largest SOC value are replaced. If no, the two energy storage subsystems with the largest SOC values are controlled to maintain the DC bus and perform the compensation action.

[0036] As described above, the charging and discharging conversion efficiency of the system is improved, and the heavy-load rate and load imbalance rate of the substation are reduced.

[0037] Further, the required minimum number of energy storage subsystems is turned on to maintain, consume or compensate the DC bus, and specifically, only the energy storage subsystem of the substation with the largest SOC value is turned on to maintain the DC bus.

[0038] If the operating discharging power of a single energy storage subsystem is greater than the power required to be compensated, only the energy storage subsystem with the largest SOC value is turned on to compensate. Otherwise, the two energy storage subsystems with the largest SOC values are turned on to compensate.

[0039] If the operating charging power of a single energy storage subsystem is greater than the power required to be consumed, only the energy storage subsystem with the smallest SOC value is turned on to compensate. Otherwise, the two energy storage subsystems with the smallest SOC values are turned on to consume.

[0040] As described above, the required minimum number of energy storage subsystems is turned on to compensate, consume or maintain the DC bus.

[0041] Further, when the shared DC bus energy storage system enters standby, the SOC values of the energy storage subsystems of each substation are determined, and the energy storage subsystem with the largest SOC value is selected to maintain the DC bus voltage, and the energy storage subsystems of the remaining substations are turned off.

[0042] When the SOC of the substation that maintains the DC bus voltage decreases to a set low power, the energy storage subsystem with the largest SOC value in the remaining substations is woken up to replace the current energy storage subsystem to maintain the DC bus voltage.

[0043] If all the SOC of the sharing DC bus energy storage system is reduced to the set low power, the control terminal starts the forced power compensation mode, and all the energy storage subsystems are compensated to the set compensation power, and then the compensation is stopped.

[0044] From the above description, it can be known that a certain amount of power is retained to maintain the DC bus, and a certain margin is retained for the consumption of photovoltaic power.

[0045] A DC bus energy storage system power reduction terminal, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the following steps:

[0046] S1, judge whether the AC power generation system outputs power, if yes, execute step S2, otherwise execute step S3;

[0047] S2, judge whether the output power of the AC power generation system is insufficient to support the load in each area, if yes, dispatch the redundant area to compensate for the insufficient area, and start the minimum required sub-energy storage system to maintain, consume or compensate the DC bus;

[0048] S3, judge whether there is an area in a heavy load state, if yes, mobilize the power grid of the light load area to compensate for the area in the heavy load state, and only start the energy storage subsystem of one area to maintain the DC bus; judge whether the output power of the power grid is greater than the first set multiple of the rated output power of the power grid, if yes, use the minimum required energy storage subsystem of the area to compensate for the output power of the power grid.

[0049] From the above description, it can be known that the beneficial effects of the present application are that a DC bus energy storage system power reduction method uses as few energy storage subsystems as possible to maintain, compensate and consume the DC bus, thereby reducing the power consumption of the shared DC bus energy storage system to maintain the DC bus without affecting the strategic operation of the energy storage system, improving the charge-discharge conversion efficiency of the system, and reducing the heavy load rate and load imbalance rate of the area.

[0050] Further, the judgment whether there is an area in a heavy load state is specifically to judge whether the sum of the load power of half or less than half of the areas is twice or more than twice the sum of the load power of the remaining areas, if yes, judge that the area whose sum of load power is twice or more than twice the sum of the load power of the remaining areas is in a heavy load state, and the remaining areas are in a light load state.

[0051] From the above description, it can be known that the judgment of the heavy load and light load of each area is realized.

[0052] Further, in step S3, the mobilization of the power grid of the light load area to compensate for the area in the heavy load state is specifically:

[0053] The heavy load area obtains power from the DC bus;

[0054] The light load area inputs power P PCS to the DC bus; 重载 非重载 / n;

[0055] In the formula, P 重载 is the sum of the power of the heavy load area, P 非重载 is the sum of the power of the light load area, and n is the number of the light load areas;

[0056] The energy storage subsystems required to compensate for the output power of the power grid include:

[0057] Obtain the total power P 补偿 required to compensate for the power grid;

[0058] Determine whether the discharging power of the energy storage subsystem with the largest SOC value is greater than P 补偿 , if so, control the energy storage subsystem with the largest SOC value to maintain the DC bus and perform a compensation action until the energy storage subsystem is empty or the discharging power is less than P 补偿 , and replace it with the remaining energy storage subsystem with the largest SOC value, if not, maintain the DC bus and perform a compensation action with the remaining two energy storage subsystems with the largest SOC values.

[0059] As described above, the charging and discharging conversion efficiency of the system is improved, and the heavy load rate and load imbalance rate of the area are reduced.

[0060] Further, the required minimum energy storage subsystems are turned on to maintain, absorb or compensate for the DC bus, specifically, only the energy storage subsystem of the area with the largest SOC value is turned on to maintain the DC bus;

[0061] If the operating discharging power of a single energy storage subsystem is greater than the power required to be compensated, only the energy storage subsystem with the largest SOC value is turned on to compensate, otherwise, the two energy storage subsystems with the largest SOC values are turned on to compensate in combination;

[0062] If the operating charging power of a single energy storage subsystem is greater than the power required to be absorbed, only the energy storage subsystem with the smallest SOC value is turned on to compensate, otherwise, the two energy storage subsystems with the smallest SOC values are turned on to absorb in combination.

[0063] As described above, the required minimum energy storage subsystems are turned on to compensate, absorb or maintain the DC bus.

[0064] ​Further, when the shared DC bus energy storage system enters standby, the SOC of the energy storage subsystem of each area is judged, and the energy storage subsystem with the largest SOC is selected to maintain the DC bus voltage, and the energy storage subsystems of the remaining areas are closed;

[0065] When the SOC of the area maintaining the DC bus voltage decreases to the set low power, the energy storage subsystem with the largest SOC in the remaining areas is woken up to replace the current energy storage subsystem to maintain the DC bus voltage;

[0066] If the SOC of all areas in the shared DC bus energy storage system decreases to the set low power, the control terminal starts the forced power compensation mode, and after all the energy storage subsystems are compensated to the set power compensation power, the power compensation is stopped.

[0067] From the above description, a certain amount of power is retained to maintain the DC bus, and a certain margin is retained for photovoltaic power consumption.

[0068] The application is used for the shared DC bus energy storage system to reduce the power consumption during operation.

[0069] Please refer to Figures 1 to 3 , the first embodiment of the application is:

[0070] A power consumption reduction method for a shared DC bus energy storage system, please refer to Figure 1 , the system is divided into multiple areas, each area includes an energy storage subsystem, a load and an AC power generation system, each area is connected to the power grid to supply power to the load, the energy storage subsystem includes an energy storage battery and a DC / DC, the energy storage battery is connected to the AC bus through the DC / DC, each area includes a separate PCS to take power from the DC grid to supply power to the load, forming a shared DC bus energy storage system, the load power P 负载 of each load is provided by the power grid in the area. 电网 , the AC power generation system input power P 交流 and the output power P 储能 of the energy storage subsystem.

[0071] Please refer to Figure 2 , the system as a whole has a control terminal, and the control terminal is connected to each energy storage subsystem to control the operation of the controller.

[0072] In this embodiment, the AC power generation system is a photovoltaic power generation system, and the system as a whole is divided into four areas. In other embodiments, the AC power generation system can also be a wind power generation system or a diesel engine power generation system.

[0073] This embodiment uses an interconnection and mutual aid strategy for scheduling, which can be understood as a process in which different substations mutually dispatch energy on the same DC bus. However, interconnection and mutual aid between substations requires that the DC bus be online. Because the DC buses between the four substations are connected in parallel, if the DC bus voltage is not established, the power between the substations cannot be mutually dispatched.

[0074] That is, the DC / DC boosts the cabinet voltage to 750V to establish the DC bus voltage U X , DC / DC establishes U X After that, DC / DC to U X Sampling is performed, if U is detected X If the voltage is lower than 750V or shows a downward trend, the DC / DC will control the cabinet to discharge and offset the U X During the process of decreasing, the voltage is stabilized at 750V. Therefore, when the shared DC bus energy storage system is in standby mode, the cabinet will continue to discharge to maintain U X This is also the main reason for the power consumption of the shared DC bus energy storage system when it is in standby mode. X The required power consumption is P damage The standby power consumption of a shared DC bus energy storage system consisting of n energy storage subsystems is n*P damage .

[0075] Please refer to Figure 3 The strategy is formulated and issued by the control terminal, which specifically includes the following steps:

[0076] S1. Determine whether the AC power generation system outputs power. If so, execute step S2; otherwise, execute step S3.

[0077] S2. Determine whether the output power of the AC power generation system in each substation is insufficient to support the load of the substation. If so, dispatch the substation with redundancy to compensate for the insufficient load, and start the minimum required sub-energy storage system to maintain, absorb or compensate the DC bus.

[0078] For example, the P of the first station 负载1 >P 交流1 , P of the second station 负载2 >P 交流2 , that is, the photovoltaic power of the first and second stations is not enough to support the load of the station, and at this time the P 负载3 <P 交流3 , P in the fourth zone 负载4 <P 交流4 , that is, the loads of the third and fourth stations are redundant. At this time, the P of the first station 共济1 = P 负载1 -P 交流1 , P of the second station共济2 = P 负载2 -P 交流2 , the P 冗余3 = P 交流3 -P 负载3 , the P 冗余4 = P 交流4 -P 负载4 , at this time the interconnection coordination strategy is executed, the redundant photovoltaic power of the third and fourth stations is input to the DC bus through the PCS, and the first and second stations take power from the DC bus through the respective PCS to realize balanced load output.

[0079] If P 共济1 + P 共济2 = P 冗余3 + P 冗余4 , it is indicated that there is no excess power to be consumed by the energy storage system, the control terminal selects the station with the highest SOC among the four stations to open the DC / DC to maintain the DC bus voltage, and closes the DC / DC of the remaining three stations, so that the power consumption P 储能总功耗 of the shared DC bus energy storage system is reduced from 4*P damage to P damage .

[0080] If P 共济1 + P 共济2 < P 冗余3 + P 冗余4 , P 消纳 = (P 冗余3 + P 冗余4 ) - (P 共济1 + P 共济2 ). The control terminal determines that the allowable charging power of the station with the smallest SOC among the four stations is greater than P 消纳 , the station is used to maintain the DC bus and consume photovoltaic power, improves the use efficiency of photovoltaic power, reduces P 储能总功耗 , and P 储能总功耗 = P damage .

[0081] In addition, the station currently consuming photovoltaic power has reached the full state or the allowable charging power is less than P 消纳 consumption in the process of power consumption, the control terminal will switch to the station with the lowest SOC among the remaining three stations to consume photovoltaic power, and disconnect the DC / DC of the current station to enter standby.

[0082] If the allowable charging power of the station with the smallest SOC is less than P 消纳 , the control terminal opens the DC / DC of the two stations with the smallest SOC to maintain the bus and consume photovoltaic power. At this time, P 储能总功耗 = 2*P damage .

[0083] Similarly, if the power of the substation that is undergoing photovoltaic consumption appears to be full, the control terminal starts the remaining substations to replace the substation, ensuring that P 储能总功耗 is always in the state of 2*P damage .

[0084] If P 共济1 + P 共济2 >P 冗余3 + P 冗余4 , P 补偿 = (P 共济1 + P 共济2 ) - (P 冗余3 + P 冗余4 ), the control terminal determines that the allowed discharge power of the substation with the largest SOC (the largest remaining power) among the four substations is greater than P 补偿 , the substation maintains the DC bus and performs power compensation, reduces the load rate of the substation, and reduces P 储能总功耗 , P 储能总功耗 =P damage .

[0085] When the allowed discharge power of the substation that is outputting load power balance for other substations is less than P 补偿 or the power is already in the empty state, the control terminal switches to the substation with the largest SOC among the remaining three substations to perform load balance power compensation, disconnects the DC / DC of the current substation, and enters standby state.

[0086] If the allowed discharge power of the substation with the largest SOC (the largest remaining power) among the four substations is less than P 补偿 , the control terminal starts the two substations with the largest SOC to output load balance power compensation, and the two substations DC / DC maintain the DC bus voltage, at this time P 储能总功耗 =2*P damage .

[0087] Similarly, if the power of the substation that is undergoing load balance power compensation output appears to be empty, the control terminal starts the remaining substations to replace the substation, ensuring that P 储能总功耗 is always in the state of 2*P damage .

[0088] S3, determine whether there is a substation in the heavy load state, if so, mobilize the light load substation to compensate for the substation in the heavy load state, and only start the energy storage subsystem of one substation to maintain the DC bus; determine whether the output power of the power grid is greater than the first set multiple of the rated output power of the power grid, if so, use the least number of substations to compensate for the output power of the power grid.

[0089] Specifically, four station area no AC power generation system power input, then the station area load power by P 电网 Provided, P 负载 =P 电网 .

[0090] If P 负载1 >>P 负载2 +P 负载3 +P 负载4 , that is, the first station area load required power more than twice the sum of the load required power of other station area, which means the first station area is in heavy load state, and other station area is in light load state.

[0091] The control terminal in order to balance the four station area P 电网 , control the second station area from the power grid connected to the second station area and input power P PCS2 =[P 负载1 -(P 负载2 +P 负载3 +P 负载4 )] / 3, control the third station area from the power grid connected to the third station area and input power P PCS3 =[P 负载1 -(P 负载2 +P 负载3 +P 负载4 )] / 3, control the fourth station area from the power grid connected to the fourth station area and input power P PCS4 =[P 负载1 -(P 负载2 +P 负载3 +P 负载4 )] / 3. At this time, the control terminal controls the PCS of the first station area to pull energy from the DC bus to supply power to the load of the first station area, P PCS1 =P PCS2 +P PCS3 +P PCS4 , P 电网1 =P 负载1 -P PCS1 . This is equivalent to the load of the first station area being supplied by the power grid of the four station areas at the same time, and the power is exchanged on the DC bus. The premise of power exchange on the DC bus is that the DC bus is stable online. In order to reduce the power consumption of maintaining the DC bus, the control terminal selects the station area with the largest SOC to establish and maintain the DC bus voltage, and the DC / DC of other station areas enters standby state, P 储能总功耗 =P damage . When the power of the station area is insufficient to maintain the DC bus or the power is about to be empty, the control terminal switches to the station area with higher SOC among the remaining station areas to maintain the DC bus, and the DC / DC of the station area is in standby state. The control terminal ensures that P 储能总功耗 always remains P damage .

[0092] When P appears 负载1 +P 负载2 >>P 负载3 +P 负载4 , the control terminal is used to balance the P of the four stations 电网 , control the third substation to take power from the grid connected to the third substation and input power P to the DC bus PCS3 =[(P 负载1 +P 负载2 )-(P 负载3 +P 负载4 )] / 2, control the fourth substation to take power from the grid connected to the fourth substation and input power P to the DC bus PCS4 =[(P 负载1 +P 负载2 )-(P 负载3 +P 负载4 )] / 2. At this time, the control terminal console PCS in the first and second zones draws energy from the DC bus to supply power to the loads in the first and second zones. PCS1 =P PCS3 , P PCS2 =P PCS4 .P 负载1 =P PCS1 +P 电网1 , P 负载2 =P PCS2 +P 电网2 The control terminal selects the largest SOC area to establish and maintain the DC bus voltage, and the DC / DC in other areas enters the standby state. At this time, P 储能总功耗 =P damage .

[0093] When the power of the substation is insufficient to maintain the DC bus or the power is about to be discharged, the control terminal switches to the substation with higher SOC in the remaining substations to maintain the DC bus, and the DCDC of this substation is on standby. The control terminal ensures that when executing the S2 strategy, the total power consumption of P energy storage is always kept at P damage .

[0094] There is no photovoltaic power input in the four areas, and the total P 电网 The power supplied to the load in the substation exceeds the rated output power P of the grid. 电网额定 At this time, the control terminal needs to control the output power of the energy storage equipment in each substation to supply power to the substation load so that P 电网 =1 / 2P 电网额定 Therefore, the power that each substation needs to provide is P PCS1 =P 负载1 -1 / 2P 电网额定1 , P PCS2 =P 负载2 -1 / 2P电网额定2 , P PCS3 =P 负载3 -1 / 2P 电网额定3 , P PCS4 =P 负载4 -1 / 2P 电网额定4 .

[0095] The total power output is P 补偿 =P PCS1 +P PCS2 +P PCS3 +P PCS4 . In order to reduce power consumption, the control terminal prioritizes the area with the largest SOC, and allows the discharge power to be greater than Pcompensation. If it is greater, the control terminal controls the area to maintain the DC bus and performs compensation action until the area is empty or the allowed discharge power is less than P 补偿 , the remaining area with the largest SOC is replaced. Throughout the process, P 储能总功耗 always remains at P damage . If the area with the largest SOC, the allowed discharge power is less than P 补偿 , the area with the larger SOC is prioritized for joint output, that is, the energy storage subsystems of the two areas with the largest remaining SOC maintain the DC bus and perform compensation action, at this time, the total power consumption of the energy storage system is 2*P damage .

[0096] When the shared DC bus energy storage system enters standby, the PCS and DCDC all enter standby state. The control terminal judges the SOC of the current energy storage subsystem, selects the area with the largest SOC (the largest remaining power) to maintain the DC bus voltage U X , and controls the remaining areas to be turned off. In this way, the power consumption of the shared DC bus energy storage system can be reduced from n*P damage to P damage . When the SOC of the area maintaining U X drops to 10%, the control terminal issues an instruction to wake up the energy storage subsystem with the largest SOC in the remaining areas to replace the current area and maintain U X . If the SOC of all areas in the shared DC bus energy storage system drops to 10%, the control terminal starts the forced power compensation mode and stops the power compensation after all energy storage subsystems are compensated to SOC=30%. Stopping power compensation when SOC=30% takes into account the following three points. First, a certain amount of power is left to maintain UX. Second, a certain amount of excess capacity is needed to accommodate photovoltaic power.

[0097] Please refer to Figure 4 , the second embodiment of the present application is:

[0098] A kind of co-direct current bus energy storage system reduces power consumption terminal 1, including memory 3, processor 2 and computer program stored in memory 3 and can be run on processor 2, when processor 2 executes computer program, the step of above-mentioned embodiment one is realized.

[0099] To sum up, the application provides a kind of co-direct current bus energy storage system reduces power consumption method, which uses as few energy storage subsystems as possible to maintain, compensate and accommodate direct current bus, thereby reducing the power consumption of the shared direct current bus energy storage system for maintaining the direct current bus without affecting the operation of the energy storage system strategy, improving the charge-discharge conversion efficiency of the system, reducing the overload rate of the area, and reducing the load imbalance rate.

[0100] The above-mentioned is only the embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent transformation, direct or indirect application in related technical fields using the content of the present application specification and drawings are also included in the patent protection scope of the present application.

Claims

1. A method for reducing power consumption of a common DC bus energy storage system, characterized in that: Including steps: S1. Determine whether the AC power generation system outputs power. If so, proceed to step S2; otherwise, proceed to step S3. S2. Determine whether the output power of the AC power generation system in each substation is insufficient to support the load of the substation. If so, dispatch redundant substations to compensate for the insufficient load and activate the minimum required sub-energy storage system to maintain, absorb or compensate the DC bus. S3. Determine whether any substation is in an overloaded state. If so, mobilize the power grid of the lightly loaded substation to compensate for the overloaded substation, and only activate the energy storage subsystem of one substation to maintain the DC bus; determine whether the output power of the grid is greater than a first set multiple of the rated output power of the grid. If so, use the energy storage subsystem of the minimum required substation to compensate for the output power of the grid; The minimum required sub-energy storage system is activated to maintain, absorb or compensate the DC bus, specifically, only the energy storage subsystem of the station with the largest SOC value is activated to maintain the DC bus; If the operating discharge power of a single energy storage subsystem is greater than the power to be compensated, only the energy storage subsystem with the largest SOC value is turned on for compensation. Otherwise, the two energy storage subsystems with the largest SOC value are turned on for combined compensation. If the operating charging power of a single energy storage subsystem is greater than the power to be absorbed, only the energy storage subsystem with the smallest SOC value is turned on for compensation. Otherwise, the two energy storage subsystems with the smallest SOC value are turned on for combined absorption. When the shared DC bus energy storage system enters standby mode, the SOC of the energy storage subsystems in each substation is determined, and the energy storage subsystem with the largest SOC is selected to maintain the DC bus voltage, while the energy storage subsystems in the remaining substations are shut down. When the SOC of the substation maintaining the DC bus voltage drops to a set low power level, the energy storage subsystem with the largest SOC among the remaining substations is awakened to take over the current energy storage subsystem to maintain the DC bus voltage. If the SOC of all substations in the shared DC bus energy storage system drops to the set low power level, the control terminal starts the forced power replenishment mode, replenishes all energy storage subsystems to the set power level, and then stops replenishing power.

2. A method for reducing power consumption of a common DC bus energy storage system according to claim 1, characterized in that: The determination of whether there are substations in a heavy-load state is specifically to determine whether the sum of the load powers of half or less of the substations is twice or more than twice the sum of the load powers of the remaining substations. If so, the substations whose sum of load powers is twice or more than twice the sum of the load powers of the remaining substations are in a heavy-load state, and the remaining substations are in a light-load state.

3. The method for reducing power consumption of a common DC bus energy storage system according to claim 2, characterized in that: In step S3, the method of mobilizing the power grid of the lightly loaded area to compensate the area in the heavy loaded state is as follows: The substation in the heavy-load state draws power from the DC bus; The light-loaded area inputs power P to the DC bus. PCS =(P 重载 -P 非重载 ) / n; Where, P 重载 is the sum of the power of the stations in the overload state, P 非重载 is the sum of the powers of the light-load zones, and n is the number of the light-load zones; The method of using the energy storage subsystem of the minimum required substations to compensate for the output power of the power grid specifically includes: Get the total power P required to compensate the grid 补偿 ; Determine whether the allowed discharge power of the energy storage subsystem with the largest SOC value is greater than P 补偿 If so, the energy storage subsystem with the largest SOC value is controlled to maintain the DC bus and perform compensation actions until the energy storage subsystem is discharged or the allowed discharge power is less than P 补偿 , it is replaced by the energy storage subsystem with the largest remaining SOC value. If not, the two energy storage subsystems with the largest remaining SOC value maintain the DC bus and perform compensation actions.

4. A power consumption reduction terminal for a common DC bus energy storage system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the following steps are implemented: S1. Determine whether the AC power generation system outputs power. If so, proceed to step S2; otherwise, proceed to step S3. S2. Determine whether the output power of the AC power generation system in each substation is insufficient to support the load of the substation. If so, dispatch redundant substations to compensate for the insufficient load and activate the minimum required sub-energy storage system to maintain, absorb or compensate the DC bus. S3. Determine whether any substation is in an overloaded state. If so, mobilize the power grid of the lightly loaded substation to compensate for the overloaded substation, and only activate the energy storage subsystem of one substation to maintain the DC bus; determine whether the output power of the grid is greater than a first set multiple of the rated output power of the grid. If so, use the energy storage subsystem of the minimum required substation to compensate for the output power of the grid; The minimum required sub-energy storage system is activated to maintain, absorb or compensate the DC bus, specifically, only the energy storage subsystem of the station with the largest SOC value is activated to maintain the DC bus; If the operating discharge power of a single energy storage subsystem is greater than the power to be compensated, only the energy storage subsystem with the largest SOC value is turned on for compensation. Otherwise, the two energy storage subsystems with the largest SOC value are turned on for combined compensation. If the operating charging power of a single energy storage subsystem is greater than the power to be absorbed, only the energy storage subsystem with the smallest SOC value is turned on for compensation. Otherwise, the two energy storage subsystems with the smallest SOC value are turned on for combined absorption. When the shared DC bus energy storage system enters standby mode, the SOC of the energy storage subsystems in each substation is determined, and the energy storage subsystem with the largest SOC is selected to maintain the DC bus voltage, while the energy storage subsystems in the remaining substations are shut down. When the SOC of the substation maintaining the DC bus voltage drops to a set low power level, the energy storage subsystem with the largest SOC among the remaining substations is awakened to take over the current energy storage subsystem to maintain the DC bus voltage. If the SOC of all substations in the shared DC bus energy storage system drops to the set low power level, the control terminal starts the forced power replenishment mode, replenishes all energy storage subsystems to the set power level, and then stops replenishing power.

5. A power consumption reduction terminal for a common DC bus energy storage system according to claim 4, characterized in that: The determination of whether there are substations in a heavy-load state is specifically to determine whether the sum of the load powers of half or less of the substations is twice or more than twice the sum of the load powers of the remaining substations. If so, the substations whose sum of load powers is twice or more than twice the sum of the load powers of the remaining substations are in a heavy-load state, and the remaining substations are in a light-load state.

6. A power consumption reduction terminal for a common DC bus energy storage system according to claim 5, characterized in that: In step S3, the method of mobilizing the power grid of the lightly loaded area to compensate the area in the heavy loaded state is as follows: The substation in the heavy-load state draws power from the DC bus; The light-loaded area inputs power P to the DC bus. PCS =(P 重载 -P 非重载 ) / n; Where, P 重载 is the sum of the power of the stations in the overload state, P 非重载 is the sum of the powers of the light-load zones, and n is the number of the light-load zones; The method of using the energy storage subsystem of the minimum required substations to compensate for the output power of the power grid specifically includes: Get the total power P required to compensate the grid 补偿 ; Determine whether the allowed discharge power of the energy storage subsystem with the largest SOC value is greater than P 补偿 If so, the energy storage subsystem with the largest SOC value is controlled to maintain the DC bus and perform compensation actions until the energy storage subsystem is discharged or the allowed discharge power is less than P 补偿 , it is replaced by the energy storage subsystem with the largest remaining SOC value. If not, the two energy storage subsystems with the largest remaining SOC value maintain the DC bus and perform compensation actions.

Images