A method and system for energy management coordinated control of energy storage converter VSG mode

Abstract

The application provides a kind of energy storage converter VSG mode energy management coordination control method and system, comprising: according to the power of energy storage converter and operation command, calculate the total power of energy storage converter, and according to the state of charge of the battery corresponding to energy storage converter, divide the state of charge interval where each battery is located;Based on total power and state of charge interval, calculate the state of charge deviation rate of each battery according to the state of charge of each battery;Based on total power and state of charge deviation rate, calculate the active power allocated to each state of charge interval battery corresponding to energy storage converter respectively;According to the active power allocated to each energy storage converter respectively, obtain the active power given value of each energy storage converter.The method and system carry out energy management coordination control to energy storage converter, maintain the stable and reasonable operation of micro-grid system without energy management system, prevent overdischarge and overcharge of battery at the same time, and protect the service life of battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energy storage converter control, and particularly relates to an energy management coordination control method and system for an energy storage converter VSG mode. BACKGROUND

[0002] Due to remote geographical location, harsh natural environment and backward power grid construction, there are a large number of powerless and power-deficient areas in remote areas. In order to solve the problem of local power shortage, a large number of renewable energy independent power supply systems, i.e. independent microgrids, are built and put into operation. These microgrid power supply systems are mostly MW-level, even tens of MW-level, and become the main power source for these remote areas.

[0003] The composition of a microgrid includes distributed power sources such as wind power and photovoltaic power, loads, energy storage, converters, energy management systems (EMS), monitoring and protection equipment, etc. The energy storage device plays a role in providing short-time power supply, power peak shaving, improving power quality and improving micro power performance in the microgrid. The energy storage device used at the present stage is mostly a storage battery.

[0004] In the entire independent microgrid system, the energy management system (EMS) ensures the stable control and economic operation of the entire microgrid system through wind, light and storage coordination control. The energy management system ensures that the entire microgrid system is in a stable and economic operation state by monitoring the state of the power supply equipment and the state of the load equipment in the entire microgrid system, and by adjusting the output of the power supply equipment and the switching of the load equipment. However, in the actual microgrid construction and operation process, due to the constraints of construction scale, construction funds and other conditions, in some early-stage constructed microgrids and microgrids with small scale and few energy storage converters, the energy management system is not configured. The energy regulation of the energy storage converter of this type of microgrid without an energy management system (EMS) mainly relies on manual adjustment control by the operation and maintenance personnel, and the adjustment speed and effect are subject to the personal experience of the operation personnel, so the adjustment speed and effect are poor.

[0005] The commonly used microgrid energy storage converter battery coordination control is mostly for the coordination control of multiple energy storage converters with batteries, which needs to collect the information of each energy storage converter and the SOC of the battery equipped for each energy storage converter to the energy management system (EMS), and uniformly coordinates and controls according to the SOC of the battery equipped for all energy storage converters. In a microgrid without an energy management system, how to perform energy management coordination control on the energy storage converters in the system, maintain the stable and reasonable operation of the microgrid system, and protect the service life of the battery lacks research.

[0006] In microgrids without energy management, the speed and effectiveness of energy coordination control for energy storage converters are limited by manual adjustments by operators. A method is needed to automatically, quickly, and accurately adjust the energy storage converters based on their operating status within the microgrid. This would allow the energy storage converters to operate in a more optimal state, preventing the batteries associated with them from being fully charged or discharged. This would ensure the stable operation of the entire microgrid system while protecting the lifespan of the batteries associated with the energy storage converters. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, this invention proposes a coordinated control method for energy management in VSG mode of an energy storage converter, comprising:

[0008] The total power of the energy storage converter is calculated based on its power and operating command, and the state of charge range of each battery is divided according to the state of charge of the corresponding battery.

[0009] Based on the total power and state of charge range, the state of charge deviation rate of each battery is calculated according to the state of charge of each battery.

[0010] Based on the total power and the state of charge deviation rate, the active power allocated to the energy storage converter corresponding to the battery in each state of charge interval is calculated respectively.

[0011] The active power setpoint of each energy storage converter is obtained based on the active power allocated to each energy storage converter.

[0012] Preferably, the step of calculating the total power of the energy storage converter based on the power of the energy storage converter and the operating command includes:

[0013] Retrieve all running commands indicating the energy storage converters currently in operation;

[0014] The total power of the energy storage converter is obtained by summing the power of the running energy storage converter as indicated by the running command.

[0015] Preferably, the step of dividing the state of charge (SOC) range of each battery according to the SOC of the corresponding battery of the energy storage converter includes:

[0016] Based on the state of charge (SOC) of the batteries corresponding to the energy storage converter, the SOC of each battery is divided into the lowest SOC range where charging is allowed only, the second lowest SOC range where discharging is specially controlled and charging is allowed, the highest SOC range where discharging is allowed only, the second highest SOC range where charging is specially controlled and discharging is allowed, and the intermediate SOC range where both charging and discharging are allowed.

[0017] Preferably, the step of calculating the state-of-charge deviation rate of each battery based on the total power and state-of-charge range includes:

[0018] When the total power is greater than 0, the state of charge interval is calculated as the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicates the first average state of charge of the energy storage converter in operation. Based on the first average state of charge, the first state of charge deviation rate of each state of charge interval is calculated as the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicates the first state of charge deviation rate of the energy storage converter in operation.

[0019] When the total power is less than 0, the second average state of charge of the energy storage converter is calculated, with the state of charge intervals being the middle state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval, and the running command indicating that the converter is in operation. Based on the second average state of charge, the second state of charge deviation rate of the energy storage converter is calculated, with each state of charge interval being the middle state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicating that the converter is in operation.

[0020] Preferably, the formula for calculating the first state-of-charge deviation rate is as follows:

[0021] SOCpc1i=(SOCi-SOCavg1) / SOCavg1

[0022] In the formula, SOCpc1i represents the first state of charge deviation rate of the energy storage converter when the i-th state of charge interval is the middle state of charge interval, the second highest state of charge interval, or the highest state of charge interval, and the running command represents the operating state of charge of the energy storage converter; SOCi represents the state of charge of the energy storage converter when the i-th state of charge interval is the middle state of charge interval, the second highest state of charge interval, or the highest state of charge interval, and the running command represents the operating state of charge of the energy storage converter; and SOCavg1 represents the first average state of charge.

[0023] Preferably, the formula for calculating the second state of charge deviation rate is as follows:

[0024] SOCpc2i=(SOCi-SOCavg2) / SOCavg2

[0025] In the formula, SOCpc2i represents the second state-of-charge deviation rate of the energy storage converter when the i-th state-of-charge interval is the intermediate state-of-charge interval, the second lowest state-of-charge interval, or the lowest state-of-charge interval, and the running command indicates that the converter is in operation; SOCi represents the state of charge of the energy storage converter when the i-th state-of-charge interval is the intermediate state-of-charge interval, the second lowest state-of-charge interval, or the lowest state-of-charge interval, and the running command indicates that the converter is in operation; and SOCavg2 represents the second average state of charge.

[0026] Preferably, the step of calculating the active power allocated to the energy storage converter for each state of charge interval based on the total power and the state of charge deviation rate includes:

[0027] When the total power is greater than 0, the active power allocation of the energy storage converter corresponding to the lowest state of charge interval is set to 0. The active power allocation of the energy storage converter corresponding to the second lowest state of charge interval is obtained according to the state of charge. Based on the total power and the first state of charge deviation rate, the active power allocation of the energy storage converters corresponding to the intermediate state of charge interval, the second highest state of charge interval and the highest state of charge interval is allocated.

[0028] When the total power is less than 0, the active power allocation of the energy storage converter corresponding to the highest state of charge interval is set to 0. The active power allocation of the energy storage converter corresponding to the second highest state of charge interval is obtained according to the state of charge. Based on the total power and the second state of charge deviation rate, the active power allocation of the energy storage converters corresponding to the intermediate state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval is allocated.

[0029] Preferably, the step of obtaining the active power allocated to the energy storage converter corresponding to the second lowest state of charge interval based on the state of charge includes:

[0030] The power at which the power is first stabilized after the energy storage converter enters the second-lowest state of charge range is taken as the first basic power.

[0031] The first proportional value is calculated as the ratio of the difference between the minimum value of the state of charge and the second lowest state of charge interval of the energy storage converter to the width of the second lowest state of charge interval.

[0032] Multiplying the first base power by the first proportional value yields the active power allocated to the energy storage converter in the second-lowest charge state range.

[0033] Preferably, the step of allocating the active power to the energy storage converters corresponding to the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval based on the total power and the first state of charge deviation rate includes:

[0034] Subtract the power allocated to the energy storage converter corresponding to the second lowest state of charge region from the total power to obtain the total power of normal discharge;

[0035] Based on the total power of normal discharge and the first state of charge deviation rate, calculate the active power allocated to the energy storage converter for the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval.

[0036] Preferably, the formulas for calculating the active power allocated to the energy storage converter for the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval are as follows:

[0037] Pset1 i=(1+SOCpc1i)*P 中_最高 / Num 中_最高

[0038] In the formula, Pset1i represents the active power allocated to the energy storage converter corresponding to the i-th intermediate state of charge interval, the second highest state of charge interval, or the highest state of charge interval when the total power is greater than 0; SOCpc1i represents the first state of charge deviation rate of the energy storage converter when the i-th state of charge interval is an intermediate state of charge interval, the second highest state of charge interval, or the highest state of charge interval, and the running command indicates that the energy storage converter is currently in operation; P 中_最高 Num represents the total power of normal discharge. 中_最高 This indicates the total number of energy storage converters corresponding to the intermediate state of charge range, the second highest state of charge range, and the highest state of charge range.

[0039] Preferably, the step of obtaining the active power allocated to the energy storage converter corresponding to the second highest state of charge interval based on the state of charge includes:

[0040] The power at which the power is first determined to be stable after the energy storage converter enters the second highest charge state range is taken as the second basic power.

[0041] The second proportional value is calculated as the ratio of the difference between the maximum value of the second highest electrical state interval and the state of charge of the energy storage converter to the width of the second highest electrical state interval.

[0042] Multiplying the second basic power by the second proportional value yields the active power allocated to the energy storage converter in the second highest charge state interval.

[0043] Preferably, based on the total power and the second state-of-charge deviation rate, the active power allocated to the energy storage converters corresponding to the intermediate state-of-charge interval, the second lowest state-of-charge interval, and the lowest state-of-charge interval includes:

[0044] Subtract the power allocated to the energy storage converter corresponding to the second highest charge state region from the total power to obtain the total power of normal charging;

[0045] Based on the total power of normal charging and the second state of charge deviation rate, calculate the active power allocated to the energy storage converter for the intermediate state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval.

[0046] Preferably, the formulas for calculating the active power allocated to the energy storage converter for the intermediate state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval are as follows:

[0047] Pset2i=(1-SOCpc2i)*P 最低_中 / Num 最低_中

[0048] In the formula, Pset2i represents the active power allocated to the energy storage converter corresponding to the i-th intermediate state of charge interval, the second lowest state of charge interval, or the lowest state of charge interval when the total power is less than 0; SOCpc2i represents the second state of charge deviation rate of the energy storage converter that is operating when the i-th state of charge interval is an intermediate state of charge interval, the second highest state of charge interval, or the highest state of charge interval; and P represents the second state of charge deviation rate of the energy storage converter that is currently operating. 最低_中 Num represents the total power of normal charging. 最低_中 This indicates the total number of energy storage converters corresponding to the intermediate state of charge (SOC), the second lowest SOC, and the lowest SOC.

[0049] Preferably, after calculating the active power allocated to the energy storage converter corresponding to each state-of-charge interval, and before obtaining the active power setpoint of each energy storage converter based on the active power allocated to each energy storage converter, the method further includes:

[0050] If any energy storage converter has an allocated active power exceeding the limit, then the active power of the energy storage converter exceeding the limit is set to the limit, and the energy storage converter exceeding the limit is excluded from active power allocation. The total power is reduced by the sum of the active power of the energy storage converters whose active power is set to the limit, resulting in a new total power. Then, based on the total power and the state of charge interval, the state of charge deviation rate of each battery is calculated according to the state of charge of each battery until the active power allocated to all energy storage converters does not exceed the limit.

[0051] Preferably, obtaining the active power setpoint value for each energy storage converter based on the active power allocated to each energy storage converter includes:

[0052] The active power assigned to each energy storage converter is used as the target value, and the actual active power collected is used as the feedback value. Proportional-integral regulation is then performed to obtain the active power setpoint for each energy storage converter.

[0053] Based on the same inventive concept, this application also provides an energy management coordination control system for a storage converter in VSG mode, which is improved in that it includes: a basic data module, a deviation rate module, a power distribution module, and a setpoint module.

[0054] The basic data module is used to calculate the total power of the energy storage converter based on the power of the energy storage converter and the operation command, and to divide the state of charge range of each battery according to the state of charge of the corresponding battery of the energy storage converter.

[0055] The deviation rate module is used to calculate the state-of-charge deviation rate of each battery based on the total power and the state-of-charge range, according to the state of charge of each battery.

[0056] The power allocation module is used to calculate the active power allocated to the energy storage converter corresponding to the battery in each state of charge interval based on the total power and the state of charge deviation rate.

[0057] The given value module is used to obtain the active power given value of each energy storage converter based on the active power allocated to each energy storage converter.

[0058] Compared with the closest existing technology, the present invention has the following beneficial effects:

[0059] (1) This invention proposes a method and system for coordinated energy management control of energy storage converters in VSG mode, comprising: calculating the total power of the energy storage converter based on its power and operating commands, and dividing the state of charge (SOC) intervals of each battery according to the SOC of the corresponding battery; calculating the SOC deviation rate of each battery based on the total power and SOC intervals; calculating the active power allocated to the energy storage converter corresponding to each battery in each SOC interval based on the total power and SOC deviation rate; and obtaining the active power setpoint of each energy storage converter based on the active power allocated to each energy storage converter. This invention enables coordinated energy management control of energy storage converters in the absence of an energy management system, maintaining the stable and reasonable operation of microgrid systems without an energy management system, while preventing battery over-discharge and over-charge, and protecting battery life.

[0060] (2) The control strategy proposed in this invention adjusts the output power (active power) to 0 when the total power of the energy storage converter is greater than 0 and the state of charge (SOC) of the converter battery is 0-20% during system operation, thus preventing the battery from being discharged completely. The adjustment result is as follows: Figures 2-3 As shown.

[0061] (3) The control strategy proposed in this invention, during system operation, if the total power of the energy storage converter is greater than 0, the SOC can be adjusted according to the SOC difference within the 20-100 range. This ensures that the energy storage converter with a high SOC1 has a large output (high active power), while the converter with a low SOC2 has a small output (low active power). The adjustment results in the battery SOC difference gradually narrowing and tending towards uniformity. The adjustment results are as follows: Figures 4-7 As shown.

[0062] (4) The control strategy proposed in this invention adjusts the output power (active power) to 0 when the total power of the energy storage converter is less than 0 and the state of charge (SOC) of the converter battery is between 90-100% during system operation, thus preventing the battery from being fully charged. The adjustment result is as follows: Figures 8-9 As shown.

[0063] (5) The control strategy proposed in this invention, during system operation, when the total power of the energy storage converter is less than 0, allows the SOC to be adjusted according to the SOC difference within the 0-90 range. This ensures that energy storage converters with a high SOC1 have high output (i.e., high active power and low charging power), while those with a low SOC2 have low output (i.e., low active power and high charging power). The adjustment results in a reduction and convergence of the battery SOC difference. The adjustment results are as follows: Figures 10-13 As shown. Attached Figure Description

[0064] Figure 1 A schematic diagram of a coordinated control method for energy management in VSG mode of an energy storage converter provided by the present invention;

[0065] Figure 2 This invention relates to a schematic diagram of the SOC state during the 0-20 range adjustment of the state of charge (SOC) of the discharge battery in an energy storage converter.

[0066] Figure 3 This invention relates to a schematic diagram of the output power P of the energy storage converter during the adjustment of the state of charge of the discharging battery in the 0-20 range.

[0067] Figure 4 This invention relates to a schematic diagram of the SOC1 state during the adjustment of the state of charge (SOC) of the discharge battery in the energy storage converter within the 20-100% range of the present invention.

[0068] Figure 5 This is a schematic diagram of the output power P1 during the adjustment of the state of charge of the energy storage converter in the 20-100 range of the discharging battery in the present invention.

[0069] Figure 6 This invention relates to a schematic diagram of the SOC2 state during the adjustment of the state of charge (SOC) of the discharge battery in the energy storage converter within the 20-100% range of the present invention.

[0070] Figure 7 This is a schematic diagram of the output power P2 during the adjustment of the state of charge of the energy storage converter in the 20-100 range of the discharging battery in the present invention.

[0071] Figure 8 This invention relates to a schematic diagram of the SOC state during the adjustment of the state of charge (SOC) of the charging battery in the energy storage converter within the 90-100% range of the present invention.

[0072] Figure 9 This invention relates to a schematic diagram of the output power P during the adjustment of the state of charge (SOC) of the charging battery in the energy storage converter within the 90-100% range of the present invention.

[0073] Figure 10 This invention relates to a schematic diagram of the SOC1 state during the 0-90% range adjustment of the state of charge (SOC) of the charging battery in the energy storage converter.

[0074] Figure 11 This invention relates to a schematic diagram of the output power P1 during the 0-90% state of charge adjustment process of the energy storage converter charging battery in the present invention.

[0075] Figure 12 This invention relates to a schematic diagram of the SOC2 state during the 0-90% range adjustment of the state of charge (SOC) of the charging battery in the energy storage converter.

[0076] Figure 13 This is a schematic diagram of the output power P2 during the 0-90% state of charge adjustment process of the energy storage converter charging battery in the present invention.

[0077] Figure 14 A schematic diagram of the basic structure of a VSG mode energy management and coordination control system for an energy storage converter provided by the present invention;

[0078] Figure 15 A detailed structural diagram of a VSG mode energy management and coordination control system for an energy storage converter provided by the present invention. Detailed Implementation

[0079] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0080] Example 1:

[0081] A schematic diagram of the energy management coordination control method for VSG mode of energy storage converter provided by this invention is shown below. Figure 1 As shown, it includes:

[0082] Step 1: Calculate the total power of the energy storage converter based on its power and operating command, and divide the state of charge range of each battery according to the state of charge of the corresponding battery of the energy storage converter.

[0083] Step 2: Based on the total power and state of charge range, calculate the state of charge deviation rate of each battery according to the state of charge of each battery;

[0084] Step 3: Based on the total power and the state of charge deviation rate, calculate the active power allocated to the energy storage converter for each battery in each state of charge interval;

[0085] Step 4: Obtain the active power setpoint for each energy storage converter based on the active power allocated to each energy storage converter.

[0086] This embodiment relates to an energy management coordination and control strategy for energy storage inverters in a standalone microgrid without an energy management system under VSG mode. It mainly includes several steps: dividing the battery SOC range, collecting and judging the information and status of each energy storage inverter and battery in the system, calculating the battery state of charge deviation rate, calculating the active power value of each energy storage inverter, handling the over-limit of active power value, and calculating the active power setpoint.

[0087] (I) Division of Battery State of Charge (SOC) Range

[0088] The State of Charge (SOC) of a battery reflects its remaining capacity. Numerically, it is defined as the ratio of remaining capacity to the total battery capacity, usually expressed as a percentage. Its value ranges from 0 to 100, with 0 indicating a fully discharged battery and 100 indicating a fully charged battery. The specific SOC intervals are divided into five ranges: 0-20%, 20-30%, 30-80%, 80-90%, and 90-100%. The 0-20% range allows only charging and not discharging, representing the lowest SOC. The 20-30% range uses a special discharge control strategy for discharging and a charging control strategy for charging, representing the second lowest SOC. The 30-80% range allows both charging and discharging, controlled by separate charging and discharging strategies, representing the middle SOC. The 80-90% range uses a special charging control strategy for charging and a discharge control strategy for discharging, representing the second highest SOC. The 90-100% range allows only discharging and not charging, representing the highest SOC.

[0089] (II) Information collection and status assessment of energy storage converter and battery

[0090] The converter collects information including its power P, operating commands, and initial active power command Porder. Battery information is collected based on the battery's state of charge (SOC).

[0091] The calculation and status assessment of converters and batteries mainly include:

[0092] (II) ① Determine the charging and discharging state of the energy storage converter based on the collected converter power P. The specific method is to continuously collect the power for time T1. If all the collected power is greater than 0, the charging and discharging state is determined to be the discharging state. If all the collected power is less than 0, the charging and discharging state is determined to be the charging state. If the collected power is both positive and negative, the previously determined charging and discharging state remains unchanged.

[0093] (ii) ② Determine whether the power of the energy storage converter is stable based on the collected converter power P. The specific method is to continuously collect the power for time T2 and determine the maximum value Pmax and minimum value Pmin of the power collected during time T2. If the difference between the maximum power Pmax and the minimum power Pmin is less than or equal to the set criterion Pstab, i.e., Pmax-Pmin≤Pstab, then the power is determined to be stable; otherwise, if the difference between the maximum power Pmax and the minimum power Pmin is greater than the set criterion Pstab, i.e., Pmax-Pmin>Pstab, then the power is determined to be unstable.

[0094] (ii) _③ Based on the collected converter power P and converter operation command, add up the power P of all converters whose operation command is 1, that is, the operation command indicates that they are running, to obtain the total power Psum of the microgrid energy storage converter.

[0095] (III) Calculation of Battery State-of-Charge Deviation Rate

[0096] (III) ① When Psum>0, the SOC of all converters with a running command of 1 and a state of charge (SOC) between 30 and 100, namely the converters in the middle state of charge range, the second highest state of charge range, and the highest state of charge range, are added together to obtain the total SOC value SOCsum1. The number of converters with a running command of 1 and a state of charge (SOC) between 30 and 100 is Num30_100. The total state of charge value is divided by the number of converters with a running command of 1 and a state of charge between 30 and 100 to obtain the average state of charge SOCavg1, that is, SOCavg1=SOCsum1 / Num0_80. The first state-of-charge deviation rate SOCpc1 is SOCpc1=(SOC-SOCavg1) / SOCavg1, and the first state-of-charge deviation rate of the converter with the i-th state of charge SOCi in the range of 30-100 is SOCpc1i=(SOCi-SOCavg1) / SOCavg1.

[0097] (III) ② When Psum < 0, the total SOC value SOCsum2 is obtained by adding the SOC values ​​of all converters with a running command of 1 and a SOC value between 0 and 80, i.e., the intermediate SOC range, the second lowest SOC range, and the lowest SOC range. The number of converters with a running command of 1 and a SOC value between 0 and 80 is Num0_80. The total SOC value is divided by the number of converters with a running command of 1 and a SOC value between 0 and 80 to obtain the average SOC value SOCavg2, i.e., SOCavg2 = SOCsum2 / Num0_80. The second SOC deviation rate SOCpc2 is SOCpc2 = (SOC - SOCavg2) / SOCavg2. The second SOC deviation rate of the converter with the i-th SOCi in the range of 0-80 is SOCpc2i = (SOCi - SOCavg2) / SOCavg2.

[0098] (iv) Calculation of active power values ​​for each energy storage inverter

[0099] (iv) ① When Psum>0, the total power of the energy storage inverter is positive, indicating that a single energy storage inverter needs to operate in a discharge state. Power is allocated differently according to the three SOC intervals: 0-20, 20-30, and 30-100. The active power in the 0-20 interval is 0; In the 20-30 SOC interval: the power record when the power is first judged to be stable after entering the 20-30 interval is the first basic power Pbase1, and the active power allocated in this interval is Pbase1*(SOC-20) / 10; In the 30-100 interval: the total power Psum of the energy storage inverter is reduced by the power allocated in the 20-30 interval to obtain the power P30_100 allocated to the energy storage inverter in the 30-100 interval, which is the total power of normal discharge. The active power allocated to the i-th energy storage inverter in the 30-100 interval is Pset1i=(1+SOCpc1i)*P30_100 / Num30_100.

[0100] (iv) ② When Psum < 0, the total power of the energy storage inverter is negative, indicating that a single energy storage inverter needs to operate in a discharge state. Power is allocated differently according to the three SOC intervals: 0-80, 80-90, and 90-100. The active power allocation in the 90-100 interval is 0; In the 80-90 interval: the power record when the power is first judged to be stable after entering this interval is the second basic power Pbase2, and the active power allocated in this interval is Pbase2*(90-SOC) / 10; In the 0-80 interval: the total power Psum of the energy storage inverter is reduced by the power allocated in the 80-90 interval to obtain the power P0_80 allocated to the energy storage inverter in the 0-80 interval, which is the total power of normal charging. The active power allocated to the i-th energy storage inverter in the 0-80 interval is: Pset2i=(1-SOCpc2 i)*P0_80 / Num0_80.

[0101] (v) Handling of Active Power Exceeding Limits

[0102] In step (iv), during the allocation of active power values, if the State of Charge (SOC) of the energy storage converters differs significantly, the active power allocated to the energy storage converter with the lower or higher SOC will exceed the maximum operating power of the converter. In this case, power over-limit handling is required. The specific handling method is as follows:

[0103] (V) ① If Psum>0, and the active power value allocated to the energy storage converter with SOC between 30 and 100 exceeds the limit in step (IV), then the converter is allocated the limit active power value. P30_100 is subtracted from the power allocated to all converters exceeding the limit to obtain a new power value P30_100New. The number of converters with SOC between 30 and 100 is subtracted from the number of converters exceeding the power limit to obtain a new number of converters with SOC between 30 and 100, Num30_100New. The remaining converters with SOC between 30 and 100 then recalculate and redistribute their active power according to steps (III) and (IV) above until no converter exceeds the power limit.

[0104] (V) ② If Psum < 0, and the active power value allocated to the energy storage converter with SOC between 0 and 80 exceeds the limit in step (IV), then the converter is allocated the limit active power value. The power allocated to all converters exceeding the limit is subtracted from P0_80 to obtain a new power value P0_80New. The number of converters with SOC between 0 and 80 is subtracted from the number of converters exceeding the power limit to obtain a new number of converters with SOC between 0 and 80, Num0_80New. The remaining converters with SOC between 0 and 80 are then recalculated and redistributed their active power according to steps (III) and (IV) above until no converter exceeds the power limit.

[0105] (vi) Calculation of active power setpoint

[0106] The active power value Pset of each energy storage converter obtained in steps (iv) and (v) is used as the target value. The actual active power value is used as the feedback value to perform proportional-integral (PI) regulation. The result is used as the active power setpoint of each energy storage converter.

[0107] The active power setpoint obtained in step (vi) is sent to the converter, which operates according to this setpoint, bringing its power closer to the active power values ​​obtained in steps (iv) and (v). Through this adjustment and control, the energy storage converter adjusts its power output according to the State of Charge (SOC), ensuring that converters with higher SOCs have greater output (i.e., higher power) and converters with lower SOCs have smaller outputs (i.e., smaller power). During operation, the SOC difference is reduced and tends to converge, which is the ideal operating state for the battery life of the energy storage converter.

[0108] Example 2:

[0109] Based on the same inventive concept, this invention also provides a coordinated control system for energy management in VSG mode of energy storage converter. Since the principles by which these devices solve technical problems are similar to those of the coordinated control method for energy management in VSG mode of energy storage converter, the repetitions will not be repeated.

[0110] Basic structure input of the system Figure 14 As shown, it includes: a basic data module, a deviation rate module, a power allocation module, and a setpoint module;

[0111] The basic data module is used to calculate the total power of the energy storage converter based on the power of the energy storage converter and the operation command, and to divide the state of charge range of each battery according to the state of charge of the corresponding battery of the energy storage converter.

[0112] The deviation rate module is used to calculate the state-of-charge deviation rate of each battery based on the total power and state-of-charge range.

[0113] The power allocation module is used to calculate the active power allocated to the energy storage converter for each battery in each state of charge interval based on the total power and the state of charge deviation rate.

[0114] The setpoint module is used to obtain the active power setpoint value of each energy storage converter based on the active power allocated to each energy storage converter.

[0115] The detailed structure of the energy management and coordination control system for the energy storage converter in VSG mode is as follows: Figure 15 As shown.

[0116] The basic data module includes: a power acquisition unit and a total power unit;

[0117] The power acquisition unit is used to acquire all running commands indicating that the energy storage converter is in operation;

[0118] The total power unit is used to sum the power of the energy storage converter that is running according to the operation command, and obtain the total power of the energy storage converter.

[0119] The deviation rate module includes: a positive power deviation rate unit and a negative power deviation rate unit;

[0120] The positive power deviation rate unit is used to calculate the first average state of charge of the energy storage converter when the total power is greater than 0, with the state of charge interval being the middle state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicating that the converter is in operation. Based on the first average state of charge, the unit calculates the first state of charge deviation rate of the energy storage converter with the state of charge interval being the middle state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicating that the converter is in operation.

[0121] The negative power deviation rate unit is used to calculate the second average state of charge (SOC) of the energy storage converter when the total power is less than 0. The SOC range is defined as the intermediate SOC range, the second lowest SOC range, and the lowest SOC range, and the running command indicates that the converter is in operation. Based on the second average SOC, the unit calculates the second SOC deviation rate of the energy storage converter when the SOC range is defined as the intermediate SOC range, the second highest SOC range, and the highest SOC range, and the running command indicates that the converter is in operation.

[0122] The power distribution module includes: a positive power distribution unit and a negative power distribution unit;

[0123] The positive power allocation unit is used to set the active power allocation of the energy storage converter corresponding to the lowest state of charge interval to 0 when the total power is greater than 0, obtain the active power allocated to the energy storage converter corresponding to the second lowest state of charge interval according to the state of charge, and allocate the active power allocated to the energy storage converter corresponding to the middle state of charge interval, the second highest state of charge interval and the highest state of charge interval according to the total power and the first state of charge deviation rate.

[0124] The negative power allocation unit is used to set the active power allocation of the energy storage converter corresponding to the highest state of charge interval to 0 when the total power is less than 0, obtain the active power allocation of the energy storage converter corresponding to the second highest state of charge interval according to the state of charge, and allocate the active power of the energy storage converter corresponding to the middle state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval according to the total power and the second state of charge deviation rate.

[0125] The positive power distribution unit includes: a first basic power subunit, a first proportional value subunit, and a second low charge state power subunit.

[0126] The first basic power sub-unit is used to obtain the power when the energy storage converter first judges that the power is stable after entering the second low charge state range as the first basic power.

[0127] The first proportional value sub-unit is used to calculate the proportion of the difference between the minimum value of the state of charge and the second lowest state of charge interval of the energy storage converter to the width of the second lowest state of charge interval as the first proportional value.

[0128] The power sub-unit for the second lowest state of charge is used to multiply the first basic power by the first proportional value to obtain the active power allocated to the energy storage converter in the second lowest state of charge interval.

[0129] The positive power distribution unit further includes: a normal discharge total power subunit and a normal discharge power distribution subunit;

[0130] The normal discharge total power subunit is used to subtract the power allocated to the energy storage converter corresponding to the second lowest state of charge region from the total power to obtain the normal discharge total power;

[0131] The normal discharge power allocation subunit is used to calculate the active power allocated to the energy storage converter for the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval based on the total normal discharge power and the first state of charge deviation rate.

[0132] The negative power distribution unit includes: a second basic power subunit, a second proportional value subunit, and a second high charge state power subunit;

[0133] The second basic power subunit is used to obtain the power when the power is first judged to be stable after the energy storage converter enters the second high charge state range.

[0134] The second proportional value sub-unit is used to calculate the ratio of the difference between the maximum value of the second highest electrical state interval and the state of charge of the energy storage converter to the width of the second highest electrical state interval as the second proportional value.

[0135] The second-highest charge state power sub-unit is used to multiply the second basic power by the second proportional value to obtain the active power allocated to the energy storage converter corresponding to the second-highest charge state interval.

[0136] The negative power distribution unit also includes: a normal charging total power subunit and a normal charging power distribution subunit;

[0137] The normal charging total power subunit is used to subtract the power allocated to the energy storage converter corresponding to the second highest charge state region from the total power to obtain the normal charging total power;

[0138] The normal charging power allocation subunit is used to calculate the active power allocated to the energy storage converter for the intermediate state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval based on the total normal charging power and the second state of charge deviation rate.

[0139] The system also includes an over-limit processing module;

[0140] The over-limit processing module is used to set the active power of energy storage converters that exceed the limit to the limit if there are any energy storage converters whose allocated active power exceeds the limit. The module also excludes the energy storage converters that exceed the limit from the active power allocation, reduces the total power by the sum of the active power of the energy storage converters whose active power is set to the limit, obtains the new total power, and calls the deviation rate module until the active power allocated to all energy storage converters does not exceed the limit.

[0141] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0142] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0143] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0144] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit its protection scope. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this application, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the application, but these changes, modifications or equivalent substitutions are all within the protection scope of the claims pending approval.

Claims

1. A coordinated control method for energy management in VSG mode of an energy storage converter, characterized in that, include: The total power of the energy storage converter is calculated based on its power and operating command, and the state of charge range of each battery is divided according to the state of charge of the corresponding battery. Based on the total power and state of charge range, the state of charge deviation rate of each battery is calculated according to the state of charge of each battery. Based on the total power and the state of charge deviation rate, the active power allocated to the energy storage converter corresponding to the battery in each state of charge interval is calculated respectively. The active power setpoint of each energy storage converter is obtained based on the active power allocated to each energy storage converter. The process of dividing the state of charge (SOC) range of each battery according to the SOC of the corresponding battery of the energy storage converter includes: Based on the state of charge of the corresponding batteries of the energy storage converter, the state of charge of each battery is divided into the lowest state of charge range where charging is allowed only, the second lowest state of charge range where discharging is specially controlled and charging is allowed, the highest state of charge range where discharging is allowed only, the second highest state of charge range where charging is specially controlled and discharging is allowed, and the intermediate state of charge range where both charging and discharging are allowed. The calculation of the state-of-charge deviation rate of each battery based on the total power and state-of-charge range includes: When the total power is greater than 0, the state of charge interval is calculated as the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicates the first average state of charge of the energy storage converter in operation. Based on the first average state of charge, the first state of charge deviation rate of each state of charge interval is calculated as the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicates the first state of charge deviation rate of the energy storage converter in operation. When the total power is less than 0, the second average state of charge of the energy storage converter is calculated, with the state of charge intervals being the middle state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval, and the running command indicating that the converter is in operation. Based on the second average state of charge, the second state of charge deviation rate of the energy storage converter is calculated, with each state of charge interval being the middle state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicating that the converter is in operation.

2. The method as described in claim 1, characterized in that, The calculation of the total power of the energy storage converter based on its power and operating command includes: Retrieve all running commands indicating the energy storage converters currently in operation; The total power of the energy storage converter is obtained by summing the power of the running energy storage converter as indicated by the running command.

3. The method as described in claim 1, characterized in that, The formula for calculating the first state-of-charge deviation rate is as follows: In the formula, This indicates that the i-th state of charge interval is an intermediate state of charge interval, the second highest state of charge interval, or the highest state of charge interval, and the running command indicates the first state of charge deviation rate of the energy storage converter currently in operation. This indicates that the i-th state of charge interval is an intermediate state of charge interval, the second highest state of charge interval, or the highest state of charge interval, and the running command indicates the state of charge of the energy storage converter currently in operation. This indicates the first average state of charge.

4. The method as described in claim 1, characterized in that, The formula for calculating the second state-of-charge deviation rate is as follows: In the formula, This indicates that the i-th state of charge interval is an intermediate state of charge interval, the second lowest state of charge interval, or the lowest state of charge interval, and the running command indicates the second state of charge deviation rate of the energy storage converter currently in operation. This indicates that the i-th state of charge interval is an intermediate state of charge interval, the second lowest state of charge interval, or the lowest state of charge interval, and the running command indicates the state of charge of the energy storage converter currently in operation. This indicates the second average state of charge.

5. The method as described in claim 1, characterized in that, The calculation of the active power allocated to the energy storage converter for each state of charge interval based on the total power and the state of charge deviation rate includes: When the total power is greater than 0, the active power allocation of the energy storage converter corresponding to the lowest state of charge interval is set to 0. The active power allocation of the energy storage converter corresponding to the second lowest state of charge interval is obtained according to the state of charge. Based on the total power and the first state of charge deviation rate, the active power allocation of the energy storage converters corresponding to the intermediate state of charge interval, the second highest state of charge interval and the highest state of charge interval is allocated. When the total power is less than 0, the active power allocation of the energy storage converter corresponding to the highest state of charge interval is set to 0. The active power allocation of the energy storage converter corresponding to the second highest state of charge interval is obtained according to the state of charge. Based on the total power and the second state of charge deviation rate, the active power allocation of the energy storage converters corresponding to the intermediate state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval is allocated.

6. The method as described in claim 5, characterized in that, The process of obtaining the active power allocated to the energy storage converter corresponding to the second lowest state of charge range based on the state of charge includes: The power at which the power is first stabilized after the energy storage converter enters the second-lowest state of charge range is taken as the first basic power. The first proportional value is calculated as the ratio of the difference between the minimum value of the state of charge and the second lowest state of charge interval of the energy storage converter to the width of the second lowest state of charge interval. Multiplying the first base power by the first proportional value yields the active power allocated to the energy storage converter in the second-lowest charge state range.

7. The method as described in claim 5, characterized in that, The step of allocating active power to the energy storage converters corresponding to the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval based on the total power and the first state of charge deviation rate includes: Subtract the power allocated to the energy storage converter corresponding to the second lowest state of charge region from the total power to obtain the total power of normal discharge; Based on the total power of normal discharge and the first state of charge deviation rate, calculate the active power allocated to the energy storage converter for the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval.

8. The method as described in claim 7, characterized in that, The formulas for calculating the active power allocated to the energy storage converter for the intermediate state of charge interval, the second highest state of charge interval, and the highest state of charge interval are as follows: Pset1 i =(1+SOCpc1 i ) P 中_最高 / Number 中_最高 In the formula, Pset1 i This indicates that when the total power is greater than 0, the first... i The active power allocated to the energy storage converter for each intermediate state of charge (SOCpc1) range, the second highest state of charge (SOC) range, or the highest state of charge (SOC) range is... i Indicates the first i The state of charge (SCC) interval is either the intermediate SCC interval, the second highest SCC interval, or the highest SCC interval, and the operating command indicates the first SCC deviation rate of the operating energy storage converter, P. 中_最高 Num represents the total power of normal discharge. 中_最高 This indicates the total number of energy storage converters corresponding to the intermediate state of charge range, the second highest state of charge range, and the highest state of charge range.

9. The method as described in claim 5, characterized in that, The process of obtaining the active power allocated to the energy storage converter corresponding to the second highest state of charge interval based on the state of charge includes: The power at which the power is first determined to be stable after the energy storage converter enters the second highest charge state range is taken as the second basic power. The second proportional value is calculated as the ratio of the difference between the maximum value of the second highest electrical state interval and the state of charge of the energy storage converter to the width of the second highest electrical state interval. Multiplying the second basic power by the second proportional value yields the active power allocated to the energy storage converter in the second highest charge state interval.

10. The method as described in claim 5, characterized in that, Based on the total power and the second state-of-charge deviation rate, the active power allocated to the energy storage converters corresponding to the intermediate state-of-charge interval, the second lowest state-of-charge interval, and the lowest state-of-charge interval is determined, including: Subtract the power allocated to the energy storage converter corresponding to the second highest charge state region from the total power to obtain the total power of normal charging; Based on the total power of normal charging and the second state of charge deviation rate, calculate the active power allocated to the energy storage converter for the intermediate state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval.

11. The method as described in claim 10, characterized in that, The formulas for calculating the active power allocated to the energy storage converter for the intermediate state of charge interval, the second lowest state of charge interval, and the lowest state of charge interval are as follows: Pset2 i =(1-SOCpc2 i ) P 最低_中 / Num 最低_中 In the formula, Pset2 i This indicates that when the total power is less than 0, the first... i The active power allocated to the energy storage converter for each intermediate state of charge (SOCpc2) range, the second lowest state of charge (SOC) range, or the lowest state of charge (SOC) range is... i Indicates the first i The state of charge (SCC) interval is either the intermediate SCC interval, the second highest SCC interval, or the highest SCC interval, and the operating command indicates the second SCC deviation rate of the operating energy storage converter, P. 最低_中 Num represents the total power of normal charging. 最低_中 This indicates the total number of energy storage converters corresponding to the intermediate state of charge range, the second lowest state of charge range, and the lowest state of charge range.

12. The method as described in claim 1, characterized in that, After calculating the active power allocated to the energy storage converter corresponding to each state of charge interval of the battery, and before obtaining the active power setpoint of each energy storage converter based on the active power allocated to each energy storage converter, the method further includes: If any energy storage converter has an allocated active power exceeding the limit, then the active power of the energy storage converter exceeding the limit is set to the limit, and the energy storage converter exceeding the limit is excluded from active power allocation. The total power is reduced by the sum of the active power of the energy storage converters whose active power is set to the limit, resulting in a new total power. Then, based on the total power and the state of charge interval, the state of charge deviation rate of each battery is calculated according to the state of charge of each battery until the active power allocated to all energy storage converters does not exceed the limit.

13. The method as described in claim 1, characterized in that, The process of obtaining the active power setpoint for each energy storage converter based on the active power allocated to each energy storage converter includes: The active power assigned to each energy storage converter is used as the target value, and the actual active power collected is used as the feedback value. Proportional-integral regulation is then performed to obtain the active power setpoint for each energy storage converter.

14. A VSG mode energy management coordination control system for an energy storage converter, characterized in that, include: Basic data module, deviation rate module, power allocation module, and setpoint module; The basic data module is used to calculate the total power of the energy storage converter based on the power of the energy storage converter and the operation command, and to divide the state of charge range of each battery according to the state of charge of the corresponding battery of the energy storage converter. The deviation rate module is used to calculate the state-of-charge deviation rate of each battery based on the total power and the state-of-charge range, according to the state of charge of each battery. The power allocation module is used to calculate the active power allocated to the energy storage converter corresponding to the battery in each state of charge interval based on the total power and the state of charge deviation rate. The given value module is used to obtain the active power given value of each energy storage converter according to the active power allocated to each energy storage converter. The process of dividing the state of charge (SOC) range of each battery according to the SOC of the corresponding battery of the energy storage converter includes: Based on the state of charge of the corresponding batteries of the energy storage converter, the state of charge of each battery is divided into the lowest state of charge range where charging is allowed only, the second lowest state of charge range where discharging is specially controlled and charging is allowed, the highest state of charge range where discharging is allowed only, the second highest state of charge range where charging is specially controlled and discharging is allowed, and the intermediate state of charge range where both charging and discharging are allowed. The deviation rate module includes: a positive power deviation rate unit and a negative power deviation rate unit; The positive power deviation rate unit is used to calculate the first average state of charge of the energy storage converter when the total power is greater than 0, with the state of charge interval being the middle state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicating that the converter is in operation. Based on the first average state of charge, the unit calculates the first state of charge deviation rate of the energy storage converter with the state of charge interval being the middle state of charge interval, the second highest state of charge interval, and the highest state of charge interval, and the running command indicating that the converter is in operation. The negative power deviation rate unit is used to calculate the second average state of charge (SOC) of the energy storage converter when the total power is less than 0. The SOC range is defined as the intermediate SOC range, the second lowest SOC range, and the lowest SOC range, and the running command indicates that the converter is in operation. Based on the second average SOC, the unit calculates the second SOC deviation rate of the energy storage converter when the SOC range is defined as the intermediate SOC range, the second highest SOC range, and the highest SOC range, and the running command indicates that the converter is in operation.

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