A single-phase totem pole energy storage converter and off-grid state determination method and device

Abstract

This invention discloses a method and apparatus for determining the grid connection / off-grid status of a single-phase totem-pole energy storage converter. It addresses the technical problems of traditional dual-closed-loop control strategies, where the desaturation and cumulative effects of the proportional-integral (PI) stage make it difficult to achieve seamless and balanced switching between grid connection and off-grid operation. Furthermore, the detection of grid connection / off-grid status often requires additional auxiliary sensors, resulting in slow speeds. The invention includes: acquiring electrical quantity information of the single-phase totem-pole energy storage converter; generating a predicted AC voltage value for the single-phase totem-pole energy storage converter at the current moment using the electrical quantity information; calculating a theoretical AC side voltage value for the single-phase totem-pole energy storage converter based on the predicted AC voltage value; obtaining an actual sampled AC side voltage value of the single-phase totem-pole energy storage converter; and determining the grid connection / off-grid status of the single-phase totem-pole energy storage converter using the actual sampled AC side voltage value and the theoretical AC side voltage value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of converter and off-grid technology, and particularly relates to a single-phase totem column type energy storage converter on-grid and off-grid state judgment method and device. BACKGROUND

[0002] Under the important background of implementing the "double carbon" goal, energy structure adjustment and new power system construction are imperative. With the deep coordination and interaction of source, network, load and storage, a flexible new mode of energy and power system will gradually emerge. This process will give rise to a large number of storage application scenarios and assembly needs, and storage will play an irreplaceable key role in the application of power systems. Compared with traditional AC / DC energy storage converters with bridges, the totem column AC / DC converter uses the least semiconductor devices. When working, the current only flows through one high-frequency switch tube and one power-frequency switch tube, so it has lower conduction loss. Therefore, the totem column AC / DC converter is the single-phase energy storage converter topology with the highest efficiency and bidirectional power flow characteristics.

[0003] The existing single-phase totem column type energy storage converter mainly adopts a double closed-loop control strategy to realize an outer voltage loop and an inner current loop. However, the steady-state and dynamic control performance is greatly affected by the control parameters, and it is difficult to set in the actual system. At the same time, under the traditional double closed-loop control strategy, due to the desaturation and cumulative effect of the proportional integral link, the on-grid and off-grid of the energy storage converter cannot be balanced and seamlessly switched, and the detection of the on-grid and off-grid state often needs an additional auxiliary sensor, which is slow. SUMMARY

[0004] The present application provides a single-phase totem column type energy storage converter on-grid and off-grid state judgment method and device, which solves the technical problem that under the traditional double closed-loop control strategy, due to the desaturation and cumulative effect of the proportional integral link, the on-grid and off-grid of the energy storage converter cannot be balanced and seamlessly switched, and the detection of the on-grid and off-grid state often needs an additional auxiliary sensor, which is slow.

[0005] The present application provides a single-phase totem column type energy storage converter on-grid and off-grid state judgment method, which comprises:

[0006] Collecting electrical quantity information of the single-phase totem column type energy storage converter;

[0007] Generating an AC voltage prediction value of the single-phase totem column type energy storage converter at the current time by using the electrical quantity information;

[0008] Calculating an AC side voltage theoretical value of the single-phase totem column type energy storage converter according to the AC voltage prediction value;

[0009] Obtaining an AC side voltage actual sampling value of the single-phase totem column type energy storage converter;

[0010] The grid connection / off-grid status of the single-phase totem-pole energy storage converter is determined by using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage.

[0011] Optionally, the step of generating the predicted AC voltage value of the single-phase totem-pole energy storage converter at the current moment using the electrical quantity information includes:

[0012] Calculate the AC converter side current value of the single-phase totem pole energy storage converter at the current moment based on the electrical quantity information;

[0013] The predicted AC voltage of the single-phase totem-pole energy storage converter at the current moment is calculated based on the current value on the AC converter side and the electrical quantity information.

[0014] Optionally, the electrical quantities include the AC side voltage sample value, AC side filter inductance value, preset prediction period, AC converter current sample value, switching function, and DC side voltage equivalent value of the single-phase totem-pole energy storage converter at the previous moment; the step of calculating the AC converter side current value of the single-phase totem-pole energy storage converter at the current moment based on the electrical quantity information includes:

[0015] The AC converter-side current value of the single-phase totem-pole energy storage converter is calculated using the AC side voltage sampling value, the AC side filter inductance value, the preset prediction period, the AC converter current sampling value, the switching function, and the DC side voltage equivalent value.

[0016] Optionally, the electrical quantities also include the AC-side filter capacitor value, the AC grid-side current sampling value, and the AC load-side current sampling value; the step of calculating the predicted AC voltage value of the single-phase totem-pole energy storage converter at the current moment based on the AC converter-side current value and the electrical quantity information includes:

[0017] The predicted AC voltage of the single-phase totem-pole energy storage converter at the current moment is calculated using the AC side filter capacitor value, the AC grid side current sampling value, the AC load side current sampling value, and the AC converter side current value.

[0018] Optionally, the predicted AC side voltage includes predicted AC side voltage in grid-connected state and predicted AC side voltage in off-grid state; the step of calculating the theoretical AC side voltage value of the single-phase totem-pole energy storage converter based on the predicted AC voltage includes:

[0019] Based on the predicted AC voltage value in the grid-connected state and the predicted AC voltage value in the off-grid state, calculate the grid-connected and off-grid duty cycles of the single-phase totem-pole energy storage converter at the current moment.

[0020] The theoretical value of the AC side voltage of the single-phase totem-pole energy storage converter is calculated based on the predicted AC voltage value in the grid-connected state, the predicted AC voltage value in the off-grid state, and the grid-connected / off-grid duty cycle.

[0021] Optionally, the grid connection / off-grid status includes both grid connection and off-grid status; the step of determining the grid connection / off-grid status of the single-phase totem-pole energy storage converter using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage includes:

[0022] Calculate the difference between the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage;

[0023] When the difference is greater than a preset threshold, the single-phase totem pole energy storage converter is determined to be in an off-grid state.

[0024] When the difference is less than a preset threshold, the single-phase totem pole energy storage converter is determined to be in grid-connected state.

[0025] Optionally, after the step of determining the grid connection / off-grid status of the single-phase totem-pole energy storage converter using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage, the method further includes:

[0026] The updated on / off-grid duty cycle of the single-phase totem pole energy storage converter is generated based on the on / off grid status.

[0027] The control signal for the single-phase totem-pole energy storage converter is generated based on the updated and off-grid duty cycle.

[0028] The present invention also provides a device for determining the off-grid status of a single-phase totem-pole energy storage converter, comprising:

[0029] The electrical quantity information acquisition module is used to collect electrical quantity information of the single-phase totem-pole energy storage converter;

[0030] An AC voltage prediction value generation module is used to generate the AC voltage prediction value of the single-phase totem-pole energy storage converter at the current moment using the electrical quantity information.

[0031] The AC side voltage theoretical value calculation module is used to calculate the AC side voltage theoretical value of the single-phase totem-pole energy storage converter based on the AC voltage prediction value.

[0032] The AC side voltage actual sampling value acquisition module is used to acquire the actual sampling value of the AC side voltage of the single-phase totem pole energy storage converter;

[0033] The grid connection / off-grid status determination module is used to determine the grid connection / off-grid status of the single-phase totem-pole energy storage converter by using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage.

[0034] The present invention also provides an electronic device, the device comprising a processor and a memory:

[0035] The memory is used to store program code and transmit the program code to the processor;

[0036] The processor is used to execute the single-phase totem pole energy storage converter and the off-grid status determination method as described above, according to the instructions in the program code.

[0037] The present invention also provides a computer-readable storage medium for storing program code for executing the off-grid status determination method for a single-phase totem-pole energy storage converter as described in any of the preceding claims.

[0038] As can be seen from the above technical solutions, the present invention has the following advantages: The present invention provides a method for determining the grid connection and off-grid status of a single-phase totem-pole energy storage converter, comprising: collecting electrical quantity information of the single-phase totem-pole energy storage converter; generating a predicted AC voltage value of the single-phase totem-pole energy storage converter at the current moment using the electrical quantity information; calculating a theoretical AC side voltage value of the single-phase totem-pole energy storage converter based on the predicted AC voltage value; obtaining an actual sampled AC side voltage value of the single-phase totem-pole energy storage converter, and determining the grid connection and off-grid status of the single-phase totem-pole energy storage converter using the actual sampled AC side voltage value and the theoretical AC side voltage value.

[0039] This invention generates a theoretical value of AC side voltage by predicting the AC voltage prediction value and compares it with the actual sampled value to determine the current grid connection / off-grid status of the single-phase totem pole energy storage converter. It can detect the grid connection / off-grid status without additional sensors, and avoids the problem of complex parameter tuning in the traditional dual closed-loop structure. It can achieve better dynamic performance and seamless grid connection / off-grid status switching control. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A flowchart illustrating the steps of a method for determining the off-grid status of a single-phase totem-pole energy storage converter, as provided in an embodiment of the present invention.

[0042] Figure 2 A schematic diagram of a single-phase totem-pole energy storage converter;

[0043] Figure 3 A flowchart illustrating the steps of a method for determining the off-grid status of a single-phase totem-pole energy storage converter, as provided in another embodiment of the present invention;

[0044] Figure 4 A schematic diagram of a predictive control system for a single-phase totem-pole energy storage converter provided in an embodiment of the present invention;

[0045] Figure 5 This is a structural block diagram of a single-phase totem-pole energy storage converter and its off-grid status determination device provided in an embodiment of the present invention. Detailed Implementation

[0046] This invention provides a method and apparatus for determining the grid connection and disconnection status of a single-phase totem-pole energy storage converter. It addresses the technical problem that, under traditional dual-closed-loop control strategies, the grid connection and disconnection of energy storage converters are difficult to achieve in a balanced and seamless manner due to the desaturation and cumulative effects of the proportional-integral link. Furthermore, the detection of grid connection and disconnection status often requires additional auxiliary sensors, resulting in slow speed.

[0047] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0048] Please see Figure 1 , Figure 1 A flowchart illustrating the steps of a method for determining the off-grid status of a single-phase totem-pole energy storage converter, as provided in an embodiment of the present invention.

[0049] The present invention provides a method for determining the grid connection and off-grid status of a single-phase totem-pole energy storage converter, which may specifically include the following steps:

[0050] Step 101: Collect electrical quantity information of the single-phase totem-pole energy storage converter;

[0051] Energy storage converters control the charging and discharging process of batteries, converting AC to DC power, and can directly supply power to AC loads in the absence of a power grid. They consist of a DC / AC bidirectional converter, a control unit, and other components.

[0052] Please see Figure 2 , Figure 2 This is a schematic diagram of a single-phase totem-pole energy storage converter, which mainly consists of a power grid, an AC circuit breaker, an AC load, AC-side filter inductors L1 and L2, and an AC-side filter capacitor C. f , by SH1 and S H2 The high-frequency bridge arm, composed of two devices, is formed by S L1 and S L2 The two devices form the power frequency bridge arm, with DC-side output capacitor C. o It consists of an energy storage battery and an equivalent DC source. The high-frequency bridge arm operates in PWM mode, while the power frequency bridge arm operates only once per cycle, realizing the commutation function of different voltage polarities.

[0053] Step 102: Use electrical quantity information to generate the current AC voltage prediction value of the single-phase totem-pole energy storage converter.

[0054] After collecting the electrical quantity information of the single-phase totem-pole energy storage converter, this electrical quantity information can be used to generate the current AC voltage prediction value of the single-phase totem-pole energy storage converter.

[0055] Step 103: Calculate the theoretical AC side voltage of the single-phase totem-pole energy storage converter based on the predicted AC voltage value;

[0056] Alternating current voltage is a voltage whose magnitude and direction change with time.

[0057] After obtaining the predicted AC voltage value of the single-phase totem-pole energy storage converter at the current moment, the theoretical value of the AC side voltage of the single-phase totem-pole energy storage converter can be calculated using the predicted AC voltage value.

[0058] Step 104: Obtain the actual sampled value of the AC side voltage of the single-phase totem-pole energy storage converter;

[0059] Step 105: Use the actual sampled value of AC side voltage and the theoretical value of AC side voltage to determine the grid connection and disconnection status of the single-phase totem-pole energy storage converter.

[0060] The grid connection / off-grid status of a single-phase totem-pole energy storage converter is used to reflect whether the single-phase totem-pole energy storage converter is connected to the power grid.

[0061] After calculating the theoretical AC voltage value of the single-phase totem-pole energy storage converter, the grid connection and off-grid status of the single-phase totem-pole energy storage converter can be determined by combining the actual sampled value of the single-phase totem-pole energy storage converter.

[0062] This invention generates a theoretical value of AC side voltage by predicting the AC voltage prediction value and compares it with the actual sampled value to determine the current grid connection / off-grid status of the single-phase totem pole energy storage converter. It can detect the grid connection / off-grid status without additional sensors, and avoids the problem of complex parameter tuning in the traditional dual closed-loop structure. It can achieve better dynamic performance and seamless grid connection / off-grid status switching control.

[0063] Please seeFigure 3 , Figure 3 A flowchart illustrating the steps of a method for determining the grid connection / off-grid status of a single-phase totem-pole energy storage converter, as provided in another embodiment of the present invention. Specifically, it may include the following steps:

[0064] Step 301: Collect electrical quantity information of the single-phase totem-pole energy storage converter;

[0065] Step 301 is the same as step 101. For details, please refer to the description of step 101. It will not be repeated here.

[0066] Step 302: Calculate the AC converter side current value of the single-phase totem-pole energy storage converter at the current moment based on the electrical quantity information;

[0067] In this embodiment of the invention, the AC converter side current value of the single-phase totem-pole energy storage converter at the current moment can be calculated based on electrical quantity information.

[0068] In one example, the electrical quantities include the AC side voltage sample value, AC side filter inductance value, preset prediction period, AC converter current sample value, switching function, and DC side voltage equivalent value of the single-phase totem-pole energy storage converter at the previous moment; the step of calculating the AC converter side current value of the single-phase totem-pole energy storage converter at the current moment based on the electrical quantity information may include: calculating the AC converter side current value of the single-phase totem-pole energy storage converter using the AC side voltage sample value, AC side filter inductance value, preset prediction period, AC converter current sample value, switching function, and DC side voltage equivalent value.

[0069] In practical implementation, the AC converter-side current value of a single-phase totem-pole energy storage converter can be calculated using the following formula. :

[0070]

[0071] in, The AC side voltage sample value at time k-1 This represents the equivalent DC-side voltage at time k-1. For switching functions, For the preset prediction period, This represents the sampled current value on the AC converter side at time k-1. and This is the value of the AC side filter inductance.

[0072]

[0073] in, This is the sampled value of the DC-side voltage at time k-1. The value of the AC voltage sampled on the grid side at time k-1 is .

[0074] Step 303: Calculate the predicted AC voltage of the single-phase totem-pole energy storage converter at the current moment based on the AC converter side current value and electrical quantity information.

[0075] After calculating the current value on the AC converter side, the predicted AC voltage value of the single-phase totem-pole energy storage converter at the current moment can be calculated by combining the electrical quantity information.

[0076] In one example, the electrical quantities also include the AC side filter capacitor value, the AC grid side current sampling value, and the AC load side current sampling value; step 303 may specifically include: using the AC side filter capacitor value, the AC grid side current sampling value, the AC load side current sampling value, and the AC converter side current value to calculate the predicted AC voltage value of the single-phase totem pole energy storage converter at the current moment.

[0077] In practical implementation, the predicted AC voltage of a single-phase totem-pole energy storage converter at the current moment can be calculated using the following formula. :

[0078]

[0079] in, This is the sampled value of the AC grid-side current. This is the sampled value of the AC load side current. This is the value of the AC side filter capacitor.

[0080] Step 304: Calculate the theoretical value of the AC side voltage of the single-phase totem-pole energy storage converter based on the predicted AC voltage value;

[0081] After obtaining the predicted AC voltage value of the single-phase totem-pole energy storage converter at the current moment, the theoretical value of the AC side voltage of the single-phase totem-pole energy storage converter can be calculated using the predicted AC voltage value.

[0082] In one example, the predicted AC side voltage includes both grid-connected and off-grid AC side voltage predictions. The step of calculating the theoretical AC side voltage of a single-phase totem-pole energy storage converter based on the predicted AC voltage may include the following sub-steps:

[0083] S41. Calculate the grid-connected and off-grid duty cycles of the single-phase totem-pole energy storage converter at the current moment based on the predicted AC voltage values ​​for grid-connected and off-grid states.

[0084] In practical implementation, and offline duty cycle It can be calculated using the following formula:

[0085]

[0086] in, Let be the error between the reference value and the actual value of the AC voltage at time k-1. For the current moment in S L The predicted AC voltage value is 1. For the current moment in S L = 0 AC voltage prediction value.

[0087] S42. Calculate the theoretical AC side voltage of the single-phase totem-pole energy storage converter based on the predicted AC voltage in grid-connected state, the predicted AC voltage in off-grid state, and the grid-connected / off-grid duty cycle.

[0088] In practical implementation, the theoretical value of the AC side voltage It can be calculated using the following formula:

[0089]

[0090] in, To utilize the sampled data at time k-1 in S L The predicted AC voltage at time k calculated under state = 1. To utilize the sampled data at time k-1 in S L = The predicted AC voltage at time k calculated under the condition of 0.

[0091] Step 305: Obtain the actual sampled value of the AC side voltage of the single-phase totem-pole energy storage converter;

[0092] Step 306: Use the actual sampled value of AC side voltage and the theoretical value of AC side voltage to determine the grid connection and disconnection status of the single-phase totem-pole energy storage converter.

[0093] After calculating the theoretical AC voltage value of the single-phase totem-pole energy storage converter, the grid connection and off-grid status of the single-phase totem-pole energy storage converter can be determined by combining the actual sampled value of the single-phase totem-pole energy storage converter.

[0094] In one example, grid-connected and off-grid states include both grid-connected and off-grid states. The steps for determining the grid-connected and off-grid states of a single-phase totem-pole energy storage converter using actual sampled AC voltage values ​​and theoretical AC voltage values ​​may include the following sub-steps:

[0095] S61, calculate the difference between the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage;

[0096] S62, when the difference is greater than the preset threshold, the single-phase totem pole energy storage converter is determined to be in an off-grid state;

[0097] S63, when the difference is less than the preset threshold, the single-phase totem pole energy storage converter is determined to be in grid-connected state.

[0098] In practical implementation, when the difference between the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage is greater than a preset threshold, the single-phase totem-pole energy storage converter can be determined to be in an off-grid state; when the difference between the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage is less than a preset threshold, the single-phase totem-pole energy storage converter can be determined to be in a grid-connected state.

[0099] Furthermore, in this embodiment of the invention, after determining the grid connection / off-grid status of the single-phase totem-pole energy storage converter using the actual sampled value and the theoretical value of the AC side voltage, the method may further include:

[0100] S1, generate the updated grid connection / off-grid duty cycle of the single-phase totem pole energy storage converter based on the grid connection / off-grid status;

[0101] In practical implementation, the update and off-grid duty cycle of a single-phase totem-pole energy storage converter can be calculated using the following formula. :

[0102]

[0103] in, Let be the error between the reference value and the actual value of the AC voltage at time k. The sampled data at time k in S L = 1 The predicted AC voltage at time k+1 calculated under state 1 The AC side voltage sample value at time k. The sampled data at time k in S L The predicted AC voltage at time k+1 is calculated under the condition of =0.

[0104] S2 generates control signals for the single-phase totem-pole energy storage converter based on the updated and off-grid duty cycle.

[0105] After calculating and obtaining the updated off-grid duty cycle, a phase-locked loop module can be used to obtain the polarity and phase information of the current grid-side voltage. Then, the PWM module selects different embedded Boost circuits according to the input voltage polarity signal to generate the control signal for the single-phase totem-pole energy storage converter.

[0106] This invention generates a theoretical value of AC side voltage by predicting the AC voltage prediction value and compares it with the actual sampled value to determine the current grid connection / off-grid status of the single-phase totem pole energy storage converter. It can detect the grid connection / off-grid status without additional sensors, and avoids the problem of complex parameter tuning in the traditional dual closed-loop structure. It can achieve better dynamic performance and seamless grid connection / off-grid status switching control.

[0107] For ease of understanding, the embodiments of the present invention will be described below through specific implementations:

[0108] Please see Figure 4 , Figure 4 This is a schematic diagram of a predictive control system for a single-phase totem-pole energy storage converter provided in an embodiment of the present invention.

[0109] First, the AD sampling module (S100) acquires the current electrical information. Then, the phase-locked loop module acquires the polarity and phase information of the current grid-side voltage. Next, the model prediction module (S200), duty cycle calculation module (S300), duty cycle adjustment module (S500), and grid connection / disconnection status identification module (S400) identify the current operating state and obtain the optimal duty cycle data. Finally, based on the voltage polarity, the PWM module (S600) generates the optimal control signal for the totem-pole energy storage converter.

[0110] Please see Figure 5 , Figure 5 This is a structural block diagram of a single-phase totem-pole energy storage converter and its off-grid status determination device provided in an embodiment of the present invention.

[0111] This invention provides a device for determining the grid connection / off-grid status of a single-phase totem-pole energy storage converter, comprising:

[0112] Electrical quantity information acquisition module 501 is used to acquire electrical quantity information of single-phase totem-pole energy storage converter;

[0113] The AC voltage prediction value generation module 502 is used to generate the AC voltage prediction value of the single-phase totem pole energy storage converter at the current moment using electrical quantity information.

[0114] The AC side voltage theoretical value calculation module 503 is used to calculate the AC side voltage theoretical value of the single-phase totem-pole energy storage converter based on the AC voltage prediction value.

[0115] The AC side voltage actual sampling value acquisition module 504 is used to acquire the actual sampling value of the AC side voltage of the single-phase totem-pole energy storage converter.

[0116] The grid connection / off-grid status judgment module 505 is used to judge the grid connection / off-grid status of a single-phase totem-pole energy storage converter by using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage.

[0117] In this embodiment of the invention, the AC voltage prediction value generation module 502 includes:

[0118] The AC converter side current value calculation submodule is used to calculate the AC converter side current value of the single-phase totem pole energy storage converter at the current moment based on electrical quantity information.

[0119] The AC voltage prediction calculation submodule is used to calculate the AC voltage prediction value of the single-phase totem-pole energy storage converter at the current moment based on the current value and electrical quantity information on the AC converter side.

[0120] In this embodiment of the invention, the electrical quantities include the AC side voltage sample value, AC side filter inductance value, preset prediction period, AC converter current sample value, switching function, and DC side voltage equivalent value of the single-phase totem-pole energy storage converter at the previous moment; the AC converter side current value calculation submodule includes:

[0121] The AC converter-side current value calculation unit is used to calculate the AC converter-side current value of a single-phase totem-pole energy storage converter using AC-side voltage sampling value, AC-side filter inductance value, preset prediction period, AC converter current sampling value, switching function, and DC-side voltage equivalent value.

[0122] In this embodiment of the invention, the electrical quantities also include the AC side filter capacitor value, the AC grid side current sampling value, and the AC load side current sampling value; the AC voltage prediction calculation submodule includes:

[0123] The AC voltage prediction calculation unit is used to calculate the AC voltage prediction value of a single-phase totem-pole energy storage converter at the current moment using the AC side filter capacitor value, AC grid side current sampling value, AC load side current sampling value, and AC converter side current value.

[0124] In this embodiment of the invention, the predicted AC side voltage value includes the predicted AC side voltage value under grid-connected state and the predicted AC side voltage value under off-grid state; the AC side voltage theoretical value calculation module 503 includes:

[0125] The grid-connected and off-grid duty cycle calculation submodule is used to calculate the grid-connected and off-grid duty cycle of the single-phase totem pole energy storage converter at the current moment based on the predicted AC voltage values ​​in the grid-connected state and the predicted AC voltage values ​​in the off-grid state.

[0126] The AC side voltage theoretical value calculation submodule is used to calculate the AC side voltage theoretical value of a single-phase totem-pole energy storage converter based on the predicted AC side voltage value in grid-connected state, the predicted AC voltage value in off-grid state, and the grid-connected / off-grid duty cycle.

[0127] In this embodiment of the invention, the grid connection and off-grid status includes a grid connection status and an off-grid status; the grid connection and off-grid status determination module 505 includes:

[0128] The difference calculation submodule is used to calculate the difference between the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage;

[0129] The off-grid status judgment submodule is used to determine that the single-phase totem pole energy storage converter is in an off-grid state when the difference is greater than a preset threshold.

[0130] The grid connection status judgment submodule is used to determine that the single-phase totem pole energy storage converter is in grid connection status when the difference is less than a preset threshold.

[0131] In this embodiment of the invention, it further includes:

[0132] The update and off-grid duty cycle generation module is used to generate the update and off-grid duty cycle of a single-phase totem pole energy storage converter based on the grid connection and off-grid status.

[0133] The control signal generation module is used to generate control signals for the single-phase totem-pole energy storage converter based on the updated and off-grid duty cycle.

[0134] This invention also provides an electronic device, which includes a processor and a memory:

[0135] The memory is used to store program code and transfer the program code to the processor;

[0136] The processor is used to execute the off-grid status determination method for a single-phase totem-pole energy storage converter according to the instructions in the program code of this invention.

[0137] This invention also provides a computer-readable storage medium for storing program code, which is used to execute the off-grid status determination method for a single-phase totem-pole energy storage converter according to this invention.

[0138] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0139] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0140] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, embodiments of the present invention can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, embodiments of the present invention can take the form of computer program products implemented 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.

[0141] Embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. 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 terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0142] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate 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.

[0143] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal equipment, causing a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal 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.

[0144] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0145] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0146] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the grid connection / off-grid status of a single-phase totem-pole energy storage converter, characterized in that, include: Collect electrical quantity information from a single-phase totem-pole energy storage converter; The predicted AC voltage of the single-phase totem-pole energy storage converter at the current moment is generated using the electrical quantity information. Calculate the theoretical AC side voltage of the single-phase totem-pole energy storage converter based on the predicted AC voltage value. Obtain the actual sampled value of the AC side voltage of the single-phase totem-pole energy storage converter; The grid connection / off-grid status of the single-phase totem-pole energy storage converter is determined by using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage. The step of generating the predicted AC voltage value of the single-phase totem-pole energy storage converter at the current moment using the electrical quantity information includes: Calculate the AC converter side current value of the single-phase totem pole energy storage converter at the current moment based on the electrical quantity information; The predicted AC voltage of the single-phase totem-pole energy storage converter at the current moment is calculated based on the current value on the AC converter side and the electrical quantity information. The electrical quantities include the AC side voltage sample value, AC side filter inductance value, preset prediction period, AC converter current sample value, switching function, and DC side voltage equivalent value of the single-phase totem-pole energy storage converter at the previous moment; the step of calculating the AC converter side current value of the single-phase totem-pole energy storage converter at the current moment based on the electrical quantity information includes: The AC converter side current value of the single-phase totem pole energy storage converter is calculated using the AC side voltage sampling value, the AC side filter inductance value, the preset prediction period, the AC converter current sampling value, the switching function, and the DC side voltage equivalent value. The electrical quantities also include the AC-side filter capacitor value, the AC grid-side current sampling value, and the AC load-side current sampling value; the step of calculating the predicted AC voltage value of the single-phase totem-pole energy storage converter at the current moment based on the AC converter-side current value and the electrical quantity information includes: The predicted AC voltage of the single-phase totem-pole energy storage converter at the current moment is calculated using the AC side filter capacitor value, the AC grid side current sampling value, the AC load side current sampling value, and the AC converter side current value. The AC voltage prediction value includes both grid-connected and off-grid AC voltage prediction values; the step of calculating the theoretical AC side voltage value of the single-phase totem-pole energy storage converter based on the AC voltage prediction value includes: Based on the predicted AC voltage values ​​for grid-connected and off-grid states, calculate the grid-connected / off-grid duty cycle of the single-phase totem-pole energy storage converter at the current moment. The theoretical AC side voltage of the single-phase totem-pole energy storage converter is calculated based on the predicted AC voltage in the grid-connected state, the predicted AC voltage in the off-grid state, and the grid-connected / off-grid duty cycle.

2. The method according to claim 1, characterized in that, The grid connection and off-grid status includes grid connection status and off-grid status; The step of determining the grid connection / off-grid status of the single-phase totem-pole energy storage converter using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage includes: Calculate the difference between the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage; When the difference is greater than a preset threshold, the single-phase totem pole energy storage converter is determined to be in an off-grid state. When the difference is less than a preset threshold, the single-phase totem pole energy storage converter is determined to be in grid-connected state.

3. The method according to claim 1, characterized in that, After the step of determining the grid connection / off-grid status of the single-phase totem-pole energy storage converter using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage, the method further includes: The updated on / off-grid duty cycle of the single-phase totem pole energy storage converter is generated based on the on / off grid status. The control signal for the single-phase totem-pole energy storage converter is generated based on the updated and off-grid duty cycle.

4. A device for determining the off-grid status of a single-phase totem-pole energy storage converter, characterized in that, include: The electrical quantity information acquisition module is used to collect electrical quantity information of the single-phase totem-pole energy storage converter; An AC voltage prediction value generation module is used to generate the AC voltage prediction value of the single-phase totem-pole energy storage converter at the current moment using the electrical quantity information. The AC side voltage theoretical value calculation module is used to calculate the AC side voltage theoretical value of the single-phase totem-pole energy storage converter based on the AC voltage prediction value. The AC side voltage actual sampling value acquisition module is used to acquire the actual sampling value of the AC side voltage of the single-phase totem pole energy storage converter; The grid connection / off-grid status determination module is used to determine the grid connection / off-grid status of the single-phase totem-pole energy storage converter by using the actual sampled value of the AC side voltage and the theoretical value of the AC side voltage. The AC voltage prediction value generation module includes: The AC converter side current value calculation submodule is used to calculate the AC converter side current value of the single-phase totem pole energy storage converter at the current moment based on electrical quantity information. The AC voltage prediction calculation submodule is used to calculate the AC voltage prediction value of the single-phase totem-pole energy storage converter at the current moment based on the AC converter side current value and electrical quantity information. The electrical quantities include the AC side voltage sample value, AC side filter inductance value, preset prediction period, AC converter current sample value, switching function, and DC side voltage equivalent value of the single-phase totem-pole energy storage converter at the previous moment; the AC converter side current value calculation submodule includes: The AC converter side current value calculation unit is used to calculate the AC converter side current value of a single-phase totem pole energy storage converter using AC side voltage sampling value, AC side filter inductance value, preset prediction period, AC converter current sampling value, switching function and DC side voltage equivalent value. The electrical quantities also include the AC side filter capacitor value, the AC grid side current sampling value, and the AC load side current sampling value; the AC voltage prediction calculation submodule includes: The AC voltage prediction calculation unit is used to calculate the AC voltage prediction value of the single-phase totem pole energy storage converter at the current moment using the AC side filter capacitor value, AC grid side current sampling value, AC load side current sampling value and AC converter side current value. The AC voltage prediction values ​​include both grid-connected and off-grid AC voltage predictions; the AC side voltage theoretical value calculation module includes: The grid-connected and off-grid duty cycle calculation submodule is used to calculate the grid-connected and off-grid duty cycles of a single-phase totem-pole energy storage converter at the current moment based on the predicted AC voltage values ​​in the grid-connected and off-grid states. The AC side voltage theoretical value calculation submodule is used to calculate the AC side voltage theoretical value of a single-phase totem-pole energy storage converter based on the predicted AC voltage value in grid-connected state, the predicted AC voltage value in off-grid state, and the grid-connected / off-grid duty cycle.

5. An electronic device, characterized in that, The device includes a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the method for determining the off-grid status of a single-phase totem pole energy storage converter according to any one of claims 1-3, based on the instructions in the program code.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store program code, which is used to execute the method for determining the off-grid status of a single-phase totem-pole energy storage converter as described in any one of claims 1-3.

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