A method, device, equipment and medium for controlling parallel operation of energy storage converters

Abstract

The present invention relates to a method, device, equipment and medium for controlling parallel operation of energy storage converters, wherein the method comprises: executing a grid-connected operation control step, wherein the grid-connected operation control step comprises the following sub-steps: obtaining a grid-connected point voltage angle, and judging whether the grid-connected point voltage angle is within a preset range; if the grid-connected point voltage angle is not within the preset range, obtaining energy storage converter port voltage zero-crossing capture data; determining a carrier adjustment time required according to the energy storage converter port voltage zero-crossing capture data; and determining a carrier adjustment time required according to a control period. T s The current carrier count value is determined by the relationship between the maximum adjustment time of the inner carrier; and the carrier synchronization adjustment of each energy storage converter under grid connection is performed based on the current carrier count value. The present invention can realize direct parallel operation of modules without communication, and reduce high-frequency harmonic circulating current when modular converters are operated in parallel.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage converters, and in particular to a method and device for controlling parallel operation of energy storage converters. Background Art

[0002] Energy storage inverters are the bridge between the battery system, the power grid and the load, and are the core equipment for realizing grid-connected charging and discharging of energy storage systems and power supply to loads. Compared with tower machines, modular inverters are more flexible and can be configured according to user needs to build different topological structures, reducing equipment R&D and operation and maintenance costs. With the continuous increase in energy storage system capacity and load power consumption, the demand for modular inverter parallel function is becoming more urgent.

[0003] In order to protect the power transmission circuit, the connection between the energy storage inverter and the grid-connected and off-grid switching device needs to be equipped with an isolation and boost device. This method increases the design difficulty of the overall microgrid and energy storage system, and requires clustering design based on the module AC or DC parameters. In addition, this method also requires the addition of hardware equipment, which increases the system cost.

[0004] The existing patent document CN116388283A discloses a multi-mobile energy storage system off-grid parallel operation control method and device, which discloses that the master-slave mode is used for parallel connection of modules based on communication, and the host gives a unified signal, and each slave uses this as a basis for carrier synchronization, thereby reducing high-frequency circulating current. At the same time, in the off-grid operation control, the host performs unified voltage loop control, and each slave performs current control, thereby meeting the control requirements of multi-module parallel operation. However, this method has high requirements for the host and communication loop. Once the host fails or the communication loop is disconnected, the system is difficult to operate. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method and device for controlling parallel operation of energy storage converters, which can realize direct parallel operation of modules without communication and reduce high-frequency harmonic circulating current when modular converters are operated in parallel.

[0006] The technical solution adopted by the present invention to solve the technical problem is: to provide a parallel operation control method for energy storage converters, to perform a grid-connected operation control step, and the grid-connected operation control step includes the following sub-steps:

[0007] Obtain the grid connection point voltage angle, and determine whether the grid connection point voltage angle is within [Δθ, 2π-Δθ], where Δθ is the control period T s The angle change value within

[0008] If the grid connection point voltage angle is not within [Δθ, 2π-Δθ], then the energy storage converter port voltage zero-crossing capture data is obtained;

[0009] Determine the carrier adjustment time required according to the zero-crossing point capture data of the energy storage converter port voltage;

[0010] Adjust the time and control period T according to the carrier s The relationship between the maximum adjustment time of the inner carrier determines the current carrier count value;

[0011] Carrier synchronization adjustment of each energy storage converter connected to the grid is performed based on the current carrier count value.

[0012] The carrier adjustment time required is ΔT = eCap count %T s Calculated, where ΔT is the carrier adjustment time, eCap count The data is captured when the voltage at the energy storage converter port passes through zero, and % is the modulo operation.

[0013] The time required to adjust the carrier and the control period T s The relationship between the maximum adjustment time of the inner carrier determines the current carrier count value, specifically:

[0014] Determine whether the carrier adjustment time is greater than the control period T s Maximum adjustment time of the inner carrier;

[0015] If the carrier adjustment time is less than or equal to the control period T s The maximum adjustment time of the inner carrier is as follows: the sum of the current carrier count value and the adjustment time required for the carrier is taken as the current carrier count value;

[0016] If the carrier adjustment time is greater than the control period T s The maximum adjustment time of the internal carrier is then the current carrier count value and the control period T s The sum of the maximum adjustment time of the inner carrier is used as the current carrier count value.

[0017] Before executing the grid-connected operation control step, the method further includes:

[0018] Obtaining the grid connection point voltage, and determining whether the grid connection point voltage is greater than a grid connection and off-grid state voltage determination threshold;

[0019] If the grid-connected point voltage is greater than the grid-connected and off-grid state voltage judgment threshold, then entering the grid-connected operation control step;

[0020] If the grid-connected point voltage is less than or equal to the grid-connected or off-grid state voltage judgment threshold, the off-grid operation control step is executed.

[0021] The off-grid operation control step includes the following sub-steps:

[0022] Obtaining a current hardware phase-locking angle, determining a carrier synchronization adjustment mode according to the current hardware phase-locking angle, and performing carrier synchronization adjustment in an off-grid situation according to the determined carrier synchronization adjustment mode;

[0023] Perform master and slave identification of each energy storage converter in off-grid operation;

[0024] Determine the off-grid parallel angle based on the identification results of each energy storage converter and its own communication status;

[0025] Determine the off-grid control voltage given value according to the active power outputted by the AC side of the energy storage converter and the identification results and communication status of each energy storage converter;

[0026] The three-phase inverter bridge is controlled based on the off-grid parallel angle and the off-grid control voltage given value.

[0027] Under off-grid operation, the master and slave identification of each energy storage converter is performed, including:

[0028] Determine whether the current master-slave flag of the energy storage converter is the master;

[0029] If the current master-slave flag is the master, the energy storage converter sends its own ID number and off-grid operation control angle;

[0030] If the current master-slave flag is a slave, determine whether the communication of the energy storage converter is normal;

[0031] If the communication is normal, the energy storage converter whose master-slave flag is the slave obtains the ID number and off-grid operation control angle of the energy storage converter whose master-slave flag is the master, and clears the communication fault count value;

[0032] If the communication is abnormal, the energy storage converter whose master-slave flag is the slave determines whether its own ID number is the ID number of the energy storage converter whose master-slave flag is the master plus one;

[0033] If so, the energy storage converter whose master-slave flag is a slave changes its master-slave flag to a master and sends its own ID number and off-grid operation control angle;

[0034] If not, the energy storage converter whose master-slave flag is the slave adds one to the communication fault count value, and determines whether its own ID number is equal to the communication fault count value;

[0035] If they are equal, the energy storage converter whose master-slave flag is a slave will change its master-slave flag to a master and send its own ID number and off-grid operation control angle.

[0036] Determining the off-grid parallel angle according to the identification results of each energy storage converter and its own communication status specifically includes:

[0037] When the energy storage converter is the host, its own off-grid operation control angle is used as the off-grid parallel angle;

[0038] When the energy storage converter is a slave and the communication is normal, the received off-grid operation control angle is used as the off-grid parallel angle;

[0039] When the energy storage converter is a slave and the communication is abnormal, the off-grid parallel angle is calculated based on the off-grid operation control angle received in the previous cycle.

[0040] The off-grid operation control angle is Calculated, where θ com (t) is the off-grid operation control angle, θ ID_0 is the initial angle of off-grid operation, Count(t) is the number of off-grid operation control counts, is the deflection angle, which is calculated as: f ref is the off-grid control frequency given value, f s To control the frequency.

[0041] The energy storage converter is a slave and when the communication is abnormal, the off-grid parallel angle is θ ID (t) = θ com (t-1)%(2π) is calculated, where θ ID (t) is the off-grid parallel angle, θ com (t-1) is the off-grid operation control angle received in the previous cycle.

[0042] The off-grid control voltage given value is determined according to the active power outputted from the AC side of the energy storage converter and the identification results and communication status of each energy storage converter, specifically:

[0043] When the energy storage converter is a slave and the communication is normal, the off-grid control voltage given value is set by u ref (t) = u ref0 -k1P(t) is calculated;

[0044] When the energy storage converter is a slave and the communication is abnormal, the off-grid control voltage setting value is set by u ref (t) = u ref0 -k2P(t) is calculated;

[0045] Among them, u ref (t) is the off-grid control voltage given value when the energy storage converter is a slave, u ref0 is the initial given value of the off-grid control voltage when the energy storage converter is a slave, P(t) is the active power output on the AC side of the energy storage converter, k1 is the operation control coefficient when the communication is normal, k2 is the operation control coefficient when the communication is abnormal, and k2>k1.

[0046] The technical solution adopted by the present invention to solve the technical problem is: to provide a parallel operation control device for energy storage converters, including a grid-connected operation control part; the grid-connected operation control part includes:

[0047] The grid connection point voltage angle judgment module is used to obtain the grid connection point voltage angle and judge whether the grid connection point voltage angle is within [Δθ, 2π-Δθ], where Δθ is the control period T s The angle change value within

[0048] An acquisition module, used for acquiring the zero-crossing capture data of the energy storage converter port voltage when the grid connection point voltage angle is not within [Δθ, 2π-Δθ];

[0049] A first determination module is used to determine the carrier adjustment time required according to the zero-crossing point capture data of the energy storage converter port voltage;

[0050] The second determination module is used to adjust the time and control period T according to the carrier s The relationship between the maximum adjustment time of the inner carrier determines the current carrier count value;

[0051] The synchronous adjustment module is used to perform carrier synchronization adjustment of each energy storage converter connected to the grid based on the current carrier count value.

[0052] The technical solution adopted by the present invention to solve its technical problem is: to provide an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the above-mentioned energy storage inverter parallel operation control method when executing the computer program.

[0053] The technical solution adopted by the present invention to solve its technical problem is: providing a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned energy storage converter parallel operation control method are implemented.

[0054] Beneficial Effects

[0055] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: the present invention uses the grid connection point voltage as a reference for carrier synchronization, reducing the high-frequency harmonic circulating current when the modular converters are operated in parallel. The present invention introduces a master-slave competition mechanism. When the master fails, the slave can autonomously switch the operating mode to the master according to the set priority, further improving the system operation reliability. The present invention can use the phase-locked angle as a basis during off-grid operation, while considering the given communication angle, to ensure stable operation of the system under abnormal communication conditions, and further reduce the fundamental wave circulating current between modules under normal communication conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a schematic diagram of the AC / DC direct parallel connection topology of the energy storage converter;

[0057] Figure 2 It is a block diagram of the overall operation of the parallel system in the first embodiment of the present invention;

[0058] Figure 3 This is a control flow chart of parallel and grid-connected operation of modular energy storage converters in the first embodiment of the present invention;

[0059] Figure 4 This is a flow chart of the carrier synchronization control of the modular energy storage converter in parallel and grid-connected in the first embodiment of the present invention;

[0060] Figure 5 This is an operation block diagram of the modular energy storage converter in parallel and off-grid mode in the first embodiment of the present invention;

[0061] Figure 6 is a block diagram of the voltage / current dual closed-loop control of the converter in the first embodiment of the present invention;

[0062] Figure 7 is a master-slave state identification flow chart in the first embodiment of the present invention;

[0063] Figure 8 This is the off-grid parallel angle calculation process in the first embodiment of the present invention. DETAILED DESCRIPTION

[0064] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0065] The first embodiment of the present invention relates to a parallel operation control method for energy storage converters. In the case of parallel grid-connected operation, the method adopts a combination of grid-connected point voltage phase-locking and hardware voltage zero-crossing capture to determine the module carrier modulation reference and achieve carrier synchronization between devices. The entire process does not require an external communication loop. In parallel off-grid operation, a master-slave competition mechanism is introduced so that when the master fails, the slave can autonomously switch to master operation. When the communication is normal at the fundamental wave circulating current suppression level, the master provides operation angle information, and each slave performs off-grid droop control according to the master angle. In the case of abnormal communication, the converter uses the AC port phase-locked angle as a reference to perform off-grid droop operation control.

[0066] Figure 1The energy storage converter is directly connected in parallel with the AC / DC topology. To facilitate the master-slave and carrier synchronous control, the ID numbers of the connected modular energy storage converters are first set in sequence. The ID numbers range from 0 to i, where the smallest number is the master and the rest are slaves, with i being the i-th converter. At the same time, an AC port voltage capture loop is designed in the converter hardware loop for hardware phase locking and carrier synchronization reference value calculation. In terms of the primary circuit, the DC side of each module is directly connected in parallel to the DC bus, and the DC bus is stabilized by the battery system. The AC side of the module is directly connected in parallel to the AC bus, and the grid-connected switch Q1 and the load switch Q2 are adjusted according to the operation control requirements to realize grid-connected or off-grid operation of the parallel system. In terms of the communication loop, each module is connected to a high-speed communication bus, and the host controls the control cycle T s The ID number is num , the running angle is sent to each slave, the slave reads the communication bus information and records the host number at the current moment.

[0067] Figure 2 The overall operation process of the modular energy storage converter connected in parallel. After the modular energy storage converter starts running, the grid connection point voltage u is obtained according to the sampling. abc The grid-connected and off-grid operation mode is judged. If the grid-connected point voltage effective value is higher than the set grid-connected and off-grid state voltage judgment threshold u abc_th If yes, it will enter the grid-connected operation mode, otherwise it will enter the off-grid operation mode.

[0068] The control process of grid-connected operation of modular energy storage converter is as follows: Figure 3 As shown in Figure 2, the main consideration in grid-connected operation control is to reduce the high-frequency harmonic circulating current. The energy storage converter reads the grid-connected point voltage angle θ through software phase locking. soft Based on this, combined with the results of the hardware circuit capturing the grid-connected point voltage, the carrier synchronization control is carried out under the grid-connected operation state. The control process is as follows Figure 4 As shown, the specific steps are as follows:

[0069] Step 1-1: Determine the grid connection point voltage angle θ soft Whether it belongs to [Δθ, 2π-Δθ], where Δθ is the control period T s The calculation method of the inner angle change value is shown in formula (1), where f s To control the frequency;

[0070] Δθ=100π / f s (1)

[0071] Step 1-2: If the software phase-locked angle is within the preset range, that is, the grid-connected voltage angle is not within [Δθ, 2π-Δθ], then Then the energy storage converter port voltage zero-crossing point capture data eCap countOtherwise, it is considered that the current parallel voltage zero-crossing point has ended, and the carrier synchronization control ends;

[0072] Step 1-3: Calculate the carrier adjustment time ΔT, the calculation method is shown in formula (2), where % is a modulo operation;

[0073] ΔT=eCap count %T s (2)

[0074] Step 1-4: To reduce the output current fluctuation caused by carrier adjustment, set the control period T s The maximum adjustment time of the inner carrier is T step , according to the carrier required to adjust the time and control period T s The relationship between the maximum adjustment time of the inner carrier determines the current carrier count value, specifically:

[0075] Determine whether the carrier adjustment time ΔT is greater than the control period T s Inner carrier maximum adjustment time T step ;

[0076] If the carrier adjustment time ΔT is less than or equal to the control period T s Inner carrier maximum adjustment time T step , the sum of the current carrier count value and the carrier adjustment time required is taken as the current carrier count value Carr count ;

[0077] If the carrier adjustment time ΔT is greater than the control period T s Inner carrier maximum adjustment time T step , then the current carrier count value and the control period T s The sum of the maximum adjustment time of the inner carrier is used as the current carrier count value Carr count .

[0078] The above method of determining the current carrier count value can be expressed as:

[0079]

[0080] Step 1-5, based on the current carrier count value Carr count Carry out synchronous adjustment of the carrier waves of each energy storage converter connected to the grid.

[0081] The off-grid operation control process of modular energy storage converter is as follows: Figure 5 As shown, the control block diagram is as follows Figure 6 As shown, the specific control process is as follows:

[0082] Step 2-1: Read the current hardware phase-lock angle θ hard, the carrier synchronization adjustment in the off-grid condition is performed in the same manner as the carrier synchronization adjustment in the grid-connected condition (i.e., steps 1-1 to 1-4);

[0083] Step 2-2: Identify the master and slave states in off-grid operation. The operation control process is as follows: Figure 7 As shown, specifically including:

[0084] The energy storage converter determines whether its current master-slave flag is the master, that is, determines its own Flag ms Is it 1?

[0085] If the current master-slave flag is the master, that is, the Flag ms =1, the energy storage converter broadcasts its own ID number to the communication bus com and off-grid operation control angle θ com (t).

[0086] If the current master-slave flag is a slave, that is, the Flag ms = 0, the energy storage converter determines whether the communication is normal, that is, determines its own Flag com Is it 1?

[0087] If the communication is normal, Flag com =1, the energy storage converter as a slave reads the broadcast information and obtains the ID number of the host com and off-grid operation control angle θ com (t), and clear the communication fault count value to zero, that is, ComFault com (t)=0.

[0088] If the communication is abnormal, Flag com = 0, the energy storage converter as a slave determines its own ID number ID num Is it the ID number of the host? com Add one. If yes, the slave machine's master-slave flag is changed to the master machine, and its ID number and off-grid operation control angle are broadcast to the communication bus. If no, the slave machine will count the communication fault value ComFault com (t) Add one and determine its own ID number com Is it equal to the communication fault count value ComFault com (t), if they are equal, the master-slave flag of the slave machine is changed to the master machine, and its own ID number and off-grid operation control angle are broadcast to the communication bus.

[0089] Through the above method, when a communication failure occurs with the host, the slave can be automatically turned into the host, thereby ensuring the operation of the entire system.

[0090] Step 2-3, each energy storage converter determines the off-grid parallel angle according to the identification result and its own communication status, such as Figure 8 As shown, specifically:

[0091] When the energy storage converter is the host, that is, Flag ms =1, the off-grid operation control angle θ com (t) as the off-grid parallel angle θ ID (t);

[0092] When the energy storage converter is a slave and the communication is normal, that is, Flag ms =0 and Flag com =1, the received off-grid operation control angle θ com (t) as the off-grid parallel angle θ ID (t);

[0093] When the energy storage converter is a slave and the communication is abnormal, that is, Flag ms =0 and Flag com = 0, based on the off-grid operation control angle θ received in the previous cycle com (t-1) Calculate the off-grid parallel angle θ ID (t).

[0094] Among them, the off-grid operation control angle θ com (t)Through Calculated, where θ com (t) is the off-grid operation control angle, θ ID_0 is the initial angle of off-grid operation, Count(t) is the off-grid operation control count times, and its expression is: Count max is the maximum value of the off-grid operation control count Count(t), Count max =f s / 50, is the deflection angle, which is calculated as: f ref is the off-grid control frequency given value, f s To control the frequency. When the energy storage converter is a slave and the communication is abnormal, the off-grid parallel angle θ ID (t) through θ ID (t) = θ com (t-1)%(2π) is calculated.

[0095] It can be seen that in this embodiment, the slave performs off-grid droop control according to the master angle, and in the case of abnormal communication, the converter performs off-grid droop operation control with reference to the AC port phase-locked angle, thereby ensuring that high-frequency circulating current is reduced even when a fault occurs.

[0096] Step 2-4, determine the off-grid control voltage given value according to the active power output on the AC side of the energy storage converter and the identification results and communication status of each energy storage converter. Calculate the active power P(t) output on the AC side of the energy storage converter. Considering that the parallel system communication is normal during the initial operation, the operation control angle of each device is the same, and the devices present a resistive output. Therefore, this implementation method can adjust the device voltage output according to the set PU curve to reduce the power frequency circulating current between devices. The PU curve is shown as follows:

[0097]

[0098] That is, when the energy storage converter is a slave and the communication is normal, the off-grid control voltage given value is obtained through u ref (t) = u ref0 -k1P(t) is calculated. When the energy storage converter is a slave and the communication is abnormal, the off-grid control voltage given value is obtained by u ref (t) = u ref0 -k2P(t) is calculated. Among them, uref(t) is the off-grid control voltage given value when the energy storage converter is a slave, u ref0 is the initial given value of the off-grid control voltage when the energy storage converter is a slave, k1 is the operation control coefficient when the communication is normal, k2 is the operation control coefficient when the communication is abnormal, and k2>k1.

[0099] Step 2-5, based on the off-grid parallel angle θ ID (t) and off-grid control voltage given value u ref (t) Controlling the three-phase inverter bridge. In this step, a voltage-current dual closed-loop control method can be used to control the three-phase inverter bridge.

[0100] It is not difficult to find that the present invention uses the grid connection point voltage as a reference for carrier synchronization, reducing the high-frequency harmonic circulating current when the modular converters are running in parallel. The present invention introduces a master-slave competition mechanism. When the master fails, the slave can autonomously switch the operating mode to the master according to the set priority, further improving the system operation reliability. The present invention can be based on the phase-locked angle during off-grid operation, while considering the given communication angle, to ensure stable operation of the system under abnormal communication conditions, and further reduce the fundamental wave circulating current between modules under normal communication conditions.

[0101] The second embodiment of the present invention relates to a parallel operation control device for energy storage converters and a parallel operation control device for multiple modular energy storage converters on the AC side, including a grid-connected operation control part; the grid-connected operation control part includes:

[0102] The grid connection point voltage angle judgment module is used to obtain the grid connection point voltage angle and judge whether the grid connection point voltage angle is within [Δθ, 2π-Δθ], where Δθ is the control period T s The angle change value within

[0103] An acquisition module, used for acquiring the zero-crossing capture data of the energy storage converter port voltage when the grid connection point voltage angle is not within [Δθ, 2π-Δθ];

[0104] A first determination module is used to determine the carrier adjustment time required according to the zero-crossing point capture data of the energy storage converter port voltage;

[0105] The second determination module is used to adjust the time and control period T according to the carrier s The relationship between the maximum adjustment time of the inner carrier determines the current carrier count value;

[0106] The synchronous adjustment module is used to perform carrier synchronization adjustment of each energy storage converter connected to the grid based on the current carrier count value.

[0107] The first determination module is configured by ΔT=eCap count %T s Calculate the carrier adjustment time, where ΔT is the carrier adjustment time, eCap count The data is captured when the voltage at the energy storage converter port passes through zero, and % is the modulo operation.

[0108] The second determining module comprises:

[0109] A judging unit, used to judge whether the carrier adjustment time required is greater than the control period T s Maximum adjustment time of the inner carrier;

[0110] The first determining unit is used to determine that the carrier adjustment time required is less than or equal to the control period T s When the maximum adjustment time of the inner carrier is reached, the sum of the current carrier count value and the adjustment time required for the carrier is taken as the current carrier count value;

[0111] The second determining unit is used to determine that the carrier adjustment time required is greater than the control period T s When the carrier maximum adjustment time is reached, the current carrier count value and the control period T s The sum of the maximum adjustment time of the inner carrier is used as the current carrier count value.

[0112] The AC side parallel operation control of the multi-modular energy storage converter also includes:

[0113] A grid connection point voltage judgment part, used to obtain the grid connection point voltage and judge whether the grid connection point voltage is greater than the grid connection and off-grid state voltage judgment threshold;

[0114] A grid-connected operation control part, used to execute a grid-connected operation control step when the grid-connected point voltage is greater than the grid-connected or off-grid state voltage judgment threshold;

[0115] The off-grid operation control part is used to execute the off-grid operation control step when the grid connection point voltage is less than or equal to the off-grid state voltage judgment threshold.

[0116] The off-grid operation control part includes:

[0117] A synchronization adjustment module, used to obtain the current hardware phase-locking angle, determine the carrier synchronization adjustment mode according to the current hardware phase-locking angle, and perform carrier synchronization adjustment in an off-grid situation according to the determined carrier synchronization adjustment mode;

[0118] An identification module is used to identify the master and slave of each energy storage converter in off-grid operation;

[0119] An off-grid parallel angle determination module is used to determine the off-grid parallel angle according to the identification results of each energy storage converter and its own communication status;

[0120] An off-grid control voltage set value determination module is used to determine an off-grid control voltage set value according to the active power outputted by the AC side of the energy storage converter and the identification results and communication status of each energy storage converter;

[0121] A control module is used to control the three-phase inverter bridge based on the off-grid parallel angle and the off-grid control voltage given value.

[0122] The identification module comprises:

[0123] A host judgment unit, used to judge whether the current master-slave flag of the energy storage converter is the host;

[0124] The first broadcast unit is used to control the energy storage converter to broadcast its own ID number and off-grid operation control angle to the communication bus when the current master-slave flag of the converter is the master;

[0125] A communication judgment unit, used to judge whether the communication of the energy storage converter is normal when the current master-slave flag of the unit is a slave;

[0126] The acquisition processing unit is used to control the energy storage converter whose master-slave flag is a slave to read the broadcast information when the communication is normal, obtain the ID number and off-grid operation control angle of the energy storage converter whose master-slave flag is a host, and clear the communication fault count value;

[0127] The first ID number judgment unit is used to control the energy storage converter whose master-slave flag is a slave to judge whether its own ID number is the ID number of the energy storage converter whose master-slave flag is a master plus one when the communication is abnormal;

[0128] The second broadcast unit is used for controlling the energy storage converter whose master-slave flag is the slave to change the master-slave flag to the master when its own ID number is increased by one, and broadcasting its own ID number and off-grid operation control angle to the communication bus;

[0129] A second ID number judgment unit is used to control the energy storage converter whose master-slave flag is the slave to increase the communication fault count value by one when its own ID number is not the ID number of the energy storage converter whose master-slave flag is the master plus one, and judge whether its own ID number is equal to the communication fault count value;

[0130] The third broadcast unit is used to control the energy storage converter whose master-slave flag is a slave to change the master-slave flag to a master when its own ID number is equal to the communication fault count value, and broadcast its own ID number and off-grid operation control angle to the communication bus.

[0131] The off-grid parallel angle determination module comprises:

[0132] A first off-grid parallel angle determination unit, configured to use its own off-grid operation control angle as an off-grid parallel angle when the energy storage converter is the host;

[0133] a second off-grid parallel angle determination unit, configured to use the received off-grid operation control angle as an off-grid parallel angle when the energy storage converter is a slave and the communication is normal;

[0134] The third off-grid parallel angle determination unit is used to calculate the off-grid parallel angle based on the off-grid operation control angle received in the previous cycle when the energy storage converter is a slave and the communication is abnormal.

[0135] The off-grid operation control angle is Calculated, where θ com (t) is the off-grid operation control angle, θ ID_0 is the initial angle of off-grid operation, Count(t) is the number of off-grid operation control counts, is the deflection angle, which is calculated as: f ref is the off-grid control frequency given value, f s To control the frequency.

[0136] The third off-grid parallel angle determination unit is configured by θ ID (t) = θ com(t-1)%(2π) calculate the off-grid parallel angle, where θ ID (t) is the off-grid parallel angle, θ com (t-1) is the off-grid operation control angle received in the previous cycle.

[0137] The off-grid control voltage set value determination module comprises:

[0138] The first off-grid control voltage given value determination unit is used to determine the energy storage converter through u ref (t) = u ref0 -k1P(t) calculates the off-grid control voltage given value;

[0139] The second off-grid control voltage given value determination unit is used to determine the energy storage converter through u ref (t) = u ref0 -k2P(t) calculates the off-grid control voltage given value;

[0140] Among them, u ref (t) is the off-grid control voltage given value when the energy storage converter is a slave, u ref0 is the initial given value of the off-grid control voltage when the energy storage converter is a slave, P(t) is the active power output on the AC side of the energy storage converter, k1 is the operation control coefficient when the communication is normal, k2 is the operation control coefficient when the communication is abnormal, and k2>k1.

[0141] The third embodiment of the present invention relates to an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the energy storage converter parallel operation control method of the first embodiment when executing the computer program.

[0142] A fourth embodiment of the present invention relates to a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the energy storage converter parallel operation control method of the first embodiment are implemented.

[0143] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0144] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0145] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction method, which is implemented in the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0146] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0147] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for controlling parallel operation of energy storage converters, characterized in that: Execute the grid-connected operation control step, the grid-connected operation control step includes the following sub-steps: Obtain the grid connection point voltage angle, and determine whether the grid connection point voltage angle is within [Δθ, 2π-Δθ], where Δθ is the control period T s The angle change value within If the grid connection point voltage angle is not within [Δθ, 2π-Δθ], then the energy storage converter port voltage zero-crossing capture data is obtained; The carrier adjustment time required is determined according to the zero-crossing capture data of the energy storage converter port voltage; wherein the carrier adjustment time required is determined by ΔT=eCap count %T s Calculated, where ΔT is the carrier adjustment time required, eCap count Capture data for the zero-crossing point of the voltage at the energy storage converter port, % is the modulo operation; Adjust the time and control period T according to the carrier s The relationship between the maximum adjustment time of the inner carrier determines the current carrier count value, specifically: Determine whether the carrier adjustment time is greater than the control period T s Maximum adjustment time of the inner carrier; If the carrier adjustment time is less than or equal to the control period T s The maximum adjustment time of the inner carrier is as follows: the sum of the current carrier count value and the adjustment time required for the carrier is taken as the current carrier count value; If the carrier adjustment time is greater than the control period T s The maximum adjustment time of the internal carrier is then the current carrier count value and the control period T s The sum of the maximum adjustment time of the inner carrier is used as the current carrier count value; Carrier synchronization adjustment of each energy storage converter connected to the grid is performed based on the current carrier count value.

2. The energy storage converter parallel operation control method according to claim 1, characterized in that: Before executing the grid-connected operation control step, the method further includes: Obtaining the grid connection point voltage, and determining whether the grid connection point voltage is greater than a grid connection and off-grid state voltage determination threshold; If the grid-connected point voltage is greater than the grid-connected and off-grid state voltage judgment threshold, then entering the grid-connected operation control step; If the grid-connected point voltage is less than or equal to the grid-connected or off-grid state voltage judgment threshold, the off-grid operation control step is executed.

3. The energy storage converter parallel operation control method according to claim 2, characterized in that: The off-grid operation control step includes the following sub-steps: Obtaining a current hardware phase-locking angle, determining a carrier synchronization adjustment mode according to the current hardware phase-locking angle, and performing carrier synchronization adjustment in an off-grid situation according to the determined carrier synchronization adjustment mode; Perform master and slave identification of each energy storage converter in off-grid operation; Determine the off-grid parallel angle based on the identification results of each energy storage converter and its own communication status; Determine the off-grid control voltage given value according to the active power outputted by the AC side of the energy storage converter and the identification results and communication status of each energy storage converter; The three-phase inverter bridge is controlled based on the off-grid parallel angle and the off-grid control voltage given value.

4. The energy storage converter parallel operation control method according to claim 3, characterized in that: The master-slave identification of each energy storage converter in the off-grid operation specifically includes: Determine whether the current master-slave flag of the energy storage converter is the master; If the current master-slave flag is the master, the energy storage converter sends its own ID number and off-grid operation control angle; If the current master-slave flag is a slave, determine whether the communication of the energy storage converter is normal; If the communication is normal, the energy storage converter whose master-slave flag is the slave obtains the ID number and off-grid operation control angle of the energy storage converter whose master-slave flag is the master, and clears the communication fault count value; If the communication is abnormal, the energy storage converter whose master-slave flag is the slave determines whether its own ID number is the ID number of the energy storage converter whose master-slave flag is the master plus one; If so, the energy storage converter whose master-slave flag is a slave changes its master-slave flag to a master and sends its own ID number and off-grid operation control angle; If not, the energy storage converter whose master-slave flag is the slave adds one to the communication fault count value, and determines whether its own ID number is equal to the communication fault count value; If they are equal, the energy storage converter whose master-slave flag is a slave will change its master-slave flag to a master and send its own ID number and off-grid operation control angle.

5. The energy storage converter parallel operation control method according to claim 4, characterized in that: Determining the off-grid parallel angle according to the identification results of each energy storage converter and its own communication status specifically includes: When the energy storage converter is the host, its own off-grid operation control angle is used as the off-grid parallel angle; When the energy storage converter is a slave and the communication is normal, the received off-grid operation control angle is used as the off-grid parallel angle; When the energy storage converter is a slave and the communication is abnormal, the off-grid parallel angle is calculated based on the off-grid operation control angle received in the previous cycle.

6. The energy storage converter parallel operation control method according to claim 5, characterized in that: The off-grid operation control angle is Calculated, where θ com (t) is the off-grid operation control angle, θ ID_0 is the initial angle of off-grid operation, Count(t) is the number of off-grid operation control counts, is the deflection angle, which is calculated as: f ref is the off-grid control frequency given value, f s To control the frequency.

7. The energy storage converter parallel operation control method according to claim 5, characterized in that: The energy storage converter is a slave and when the communication is abnormal, the off-grid parallel angle is θ ID (t) = θ com (t-1)%(2π) is calculated, where θ ID (t) is the off-grid parallel angle, θ com (t-1) is the off-grid operation control angle received in the previous cycle.

8. The energy storage converter parallel operation control method according to claim 3, characterized in that: The off-grid control voltage given value is determined according to the active power outputted from the AC side of the energy storage converter and the identification results and communication status of each energy storage converter, specifically: When the energy storage converter is a slave and the communication is normal, the off-grid control voltage given value is set by u ref (t) = u ref0 -k1P(t) is calculated; When the energy storage converter is a slave and the communication is abnormal, the off-grid control voltage setting value is set by u ref (t) = u ref0 -k2P(t) is calculated; Among them, u ref (t) is the off-grid control voltage given value when the energy storage converter is a slave, u ref0 is the initial given value of the off-grid control voltage when the energy storage converter is a slave, P(t) is the active power output on the AC side of the energy storage converter, k1 is the operation control coefficient when the communication is normal, k2 is the operation control coefficient when the communication is abnormal, and k2>k1.

9. A parallel operation control device for energy storage converters, characterized in that: Including grid-connected operation control part; The grid-connected operation control part includes: The grid connection point voltage angle judgment module is used to obtain the grid connection point voltage angle and judge whether the grid connection point voltage angle is within [Δθ, 2π-Δθ], where Δθ is the control period T s The angle change value within An acquisition module, used for acquiring the zero-crossing capture data of the energy storage converter port voltage when the grid connection point voltage angle is not within [Δθ, 2π-Δθ]; The first determination module is used to determine the carrier adjustment time required according to the zero-crossing capture data of the energy storage converter port voltage; the first determination module determines the carrier adjustment time required according to ΔT=eCap count %T s Calculate the carrier adjustment time, where ΔT is the carrier adjustment time, eCap c ount is the data captured at the zero-crossing point of the voltage at the energy storage converter port, and % is the modulo operation; The second determination module is used to adjust the time and control period T according to the carrier s The current carrier count value is determined based on the relationship between the maximum adjustment time of the inner carrier; the second determination module includes: A judging unit, used to judge whether the carrier adjustment time required is greater than the control period T s Maximum adjustment time of the inner carrier; The first determining unit is used to determine that the carrier adjustment time required is less than or equal to the control period T s When the maximum adjustment time of the inner carrier is reached, the sum of the current carrier count value and the adjustment time required for the carrier is taken as the current carrier count value; The second determining unit is used to determine that the carrier adjustment time required is greater than the control period T s When the carrier maximum adjustment time is reached, the current carrier count value and the control period T s The sum of the maximum adjustment time of the inner carrier is used as the current carrier count value; The synchronous adjustment module is used to perform carrier synchronization adjustment of each energy storage converter connected to the grid based on the current carrier count value.

10. An electronic device 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 steps of the energy storage converter parallel operation control method as described in any one of claims 1-8 are implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the energy storage converter parallel operation control method as claimed in any one of claims 1 to 8 are implemented.

Images