Multi-region micro-grid voltage coordination control method, device, equipment and medium

Abstract

The invention relates to a multi-region micro-grid voltage coordination control method, device and equipment and a medium, and the method comprises the steps: designing a current compensation mode and a voltage control mode; analyzing the electric energy quality requirement of each sub-microgrid, adopting the voltage control module for the sub-microgrid of which the electric energy quality requirement meets a preset requirement, and adopting a current compensation mode for the sub-microgrid of which the electric energy quality requirement does not meet the preset requirement; and a dual-mode operation switching control algorithm is adopted to realize switching control of a voltage control module and a current compensation mode and cooperative compensation of each sub-micro-grid. The method solves the problems that flexible interaction of adjustable resources is lacked between different sub micro-grids, the overall adjustment capability of the system is not strong, and the electric energy quality problems of voltage support, harmonic waves and the like are difficult to solve at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of microgrid dynamic control, and in particular to a multi-region microgrid voltage coordinated control method, device, equipment and medium. Background Art

[0002] In a multi-regional microgrid composed of multiple sub-microgrids, each sub-microgrid usually needs to meet different engineering needs and has different voltage quality requirements. The power flow distribution of the common connection bus is affected by the output power fluctuations of multiple sub-microgrids, which makes it easy to have problems such as voltage over-limit, excessive harmonic content, and unbalanced current caused by unbalanced distributed generation. There is a lack of flexible interaction of adjustable resources between different sub-microgrids, and the overall regulation ability of the system is not strong, making it difficult to support the solution of its voltage problems while compensating for harmonic currents.

[0003] At present, the main method for grid-connected point power management is to install additional static reactive compensation devices and external power filters, but none of them considers using the remaining capacity of the grid-connected inverter of the microgrid itself for power quality management. Both require access to active and reactive power sources, which results in large investments and decentralized control designs. Furthermore, the current power quality improvement scheme generally adopts the principle of hierarchical zoning and decentralized control. For typical rural microgrid systems, this principle will result in a large waste of resources, and the grid-connected points cannot be uniformly controlled. Summary of the invention

[0004] The present invention provides a multi-region microgrid voltage coordination control method, device, equipment and medium to solve the problem of lack of flexible interaction of adjustable resources between different sub-microgrids, weak overall regulation capability of the system, and difficulty in simultaneously solving power quality problems such as voltage support and harmonics.

[0005] The technical solution adopted by the present invention to solve the technical problem is: to provide a multi-region microgrid voltage coordination control method, comprising the following steps:

[0006] Design current compensation mode and voltage control mode;

[0007] Analyze the power quality requirements of each sub-microgrid, adopt the voltage control module for the sub-microgrid whose power quality requirements meet the preset requirements, and adopt the current compensation mode for the sub-microgrid whose power quality requirements do not meet the preset requirements;

[0008] The control algorithm of dual-mode operation switching is adopted to realize the switching control of the voltage control module and the current compensation mode and the coordinated compensation of each sub-microgrid, wherein the control algorithm of the dual-mode operation switching is specifically as follows:

[0009] Establish the droop curve of the sub-microgrid power generation and current compensation coefficient, and obtain the current compensation coefficient based on the actual working conditions;

[0010] The obtained current compensation coefficient is adjusted to obtain the compensation coefficient ratio;

[0011] The harmonic compensation of each sub-microgrid working in the current compensation mode is distributed through the compensation coefficient ratio;

[0012] According to the detected voltage quality, a sub-microgrid that enters a voltage control mode is selected from the sub-microgrids operating in the current compensation mode.

[0013] The current compensation mode is specifically:

[0014] The three-phase voltage and current values ​​of the input bus common coupling point are transformed from the stationary coordinate system abc to the dq rotating coordinate system;

[0015] The voltage component and the current component obtained after the coordinate transformation are subjected to low-pass filtering, and the result after the low-pass filtering is subjected to pq transformation to obtain the positive sequence fundamental wave active current component;

[0016] The positive sequence fundamental active current component is transformed from the dq rotating coordinate system to the stationary coordinate system abc to obtain the fundamental current;

[0017] The obtained fundamental current is subtracted from the three-phase current value of the input bus common coupling point to obtain the compensation current;

[0018] The grid-connected control adopts PQ control, and its output is the grid-connected reference current. The grid-connected reference current is added to the compensation current to obtain the input total reference current, and the input total reference current is input into the PR controller to generate a PWM wave.

[0019] The voltage control mode is specifically as follows: adding an AC voltage amplitude outer loop to the voltage control structure, and adjusting the reactive current reference value through a voltage closed loop; the output of the AC voltage amplitude outer loop is used as a given value of the q-axis output current inner loop.

[0020] The control equation of the AC voltage amplitude outer loop is expressed as: oqref =k tp (U tref -U t )+k ti ∫(U tref -U t )dt, where i oqref is the output of the AC voltage amplitude outer loop, k tp and k ti are the proportional coefficient and integral coefficient of the PI controller in the AC voltage amplitude outer loop respectively; U tref is the reference value of the AC voltage amplitude, U t is the voltage amplitude at the bus common coupling point.

[0021] The current compensation coefficient is α x =1-Pk i Calculated, where α x is the current compensation coefficient, P is the power generation of the microgrid, k i is the droop coefficient determined according to the sub-microgrid.

[0022] When adjusting the obtained current compensation coefficient, use To adjust, is the compensation coefficient ratio, α x is the current compensation coefficient, and n is the number of sub-microgrids working in the current compensation mode.

[0023] The selecting, according to the detected voltage quality, a sub-microgrid that enters the voltage control mode from the sub-microgrids operating in the current compensation mode is specifically:

[0024] Detecting voltage quality, when it is detected that the voltage quality does not meet the requirements, selecting the sub-microgrid corresponding to the compensator with the smallest current compensation coefficient to exit the current compensation mode and enter the voltage control mode;

[0025] Perform voltage quality verification. If the voltage quality meets the requirements, operate according to the current state. If the voltage quality does not meet the requirements, the sub-microgrid corresponding to the compensator with a smaller current compensation coefficient in the current state will exit the current compensation mode and enter the voltage control mode, and re-perform voltage quality verification until the voltage quality meets the requirements.

[0026] The technical solution adopted by the present invention to solve the technical problem is: to provide a multi-region microgrid voltage coordination control device, comprising:

[0027] Design module, used to design current compensation mode and voltage control mode;

[0028] An initial control mode determination module is used to analyze the power quality requirements of each sub-microgrid, and adopt the voltage control module for the sub-microgrid whose power quality requirements meet the preset requirements, and adopt the current compensation mode for the sub-microgrid whose power quality requirements do not meet the preset requirements;

[0029] The control module is used to implement the switching control of the voltage control module and the current compensation mode and the coordinated compensation of each sub-microgrid by adopting the control algorithm of the dual-mode operation switching, wherein the control algorithm of the dual-mode operation switching is specifically:

[0030] Establish the droop curve of the sub-microgrid power generation and current compensation coefficient, and obtain the current compensation coefficient based on the actual working conditions;

[0031] The obtained current compensation coefficient is adjusted to obtain the compensation coefficient ratio;

[0032] The harmonic compensation of each sub-microgrid working in the current compensation mode is distributed through the compensation coefficient ratio;

[0033] According to the detected voltage quality, a sub-microgrid that enters a voltage control mode is selected from the sub-microgrids operating in the current compensation mode.

[0034] The current compensation mode is specifically:

[0035] The three-phase voltage and current values ​​of the input bus common coupling point are transformed from the stationary coordinate system abc to the dq rotating coordinate system;

[0036] The voltage component and the current component obtained after the coordinate transformation are subjected to low-pass filtering, and the result after the low-pass filtering is subjected to pq transformation to obtain the positive sequence fundamental wave active current component;

[0037] The positive sequence fundamental active current component is transformed from the dq rotating coordinate system to the stationary coordinate system abc to obtain the fundamental current;

[0038] The obtained fundamental current is subtracted from the three-phase current value of the input bus common coupling point to obtain the compensation current;

[0039] The grid-connected control adopts PQ control, and its output is the grid-connected reference current. The grid-connected reference current is added to the compensation current to obtain the input total reference current, and the input total reference current is input into the PR controller to generate a PWM wave.

[0040] The voltage control mode is specifically as follows: adding an AC voltage amplitude outer loop to the voltage control structure, and adjusting the reactive current reference value through a voltage closed loop; the output of the AC voltage amplitude outer loop is used as a given value of the q-axis output current inner loop.

[0041] The control equation of the AC voltage amplitude outer loop is expressed as: oqref =k tp (U tref -U t )+k ti ∫(U tref -U t )dt, where i oqref is the output of the AC voltage amplitude outer loop, k tp and k ti are the proportional coefficient and integral coefficient of the PI controller in the AC voltage amplitude outer loop respectively; U tref is the reference value of the AC voltage amplitude, U t is the voltage amplitude at the bus common coupling point.

[0042] The current compensation coefficient is α x =1-Pk i Calculated, where αx is the current compensation coefficient, P is the power generation of the microgrid, k i is the droop coefficient determined according to the sub-microgrid.

[0043] When adjusting the obtained current compensation coefficient, use To adjust, is the compensation coefficient ratio, α x is the current compensation coefficient, and n is the number of sub-microgrids working in the current compensation mode.

[0044] The selecting, according to the detected voltage quality, a sub-microgrid that enters the voltage control mode from the sub-microgrids operating in the current compensation mode is specifically:

[0045] Detecting voltage quality, when it is detected that the voltage quality does not meet the requirements, selecting the sub-microgrid corresponding to the compensator with the smallest current compensation coefficient to exit the current compensation mode and enter the voltage control mode;

[0046] Perform voltage quality verification. If the voltage quality meets the requirements, operate according to the current state. If the voltage quality does not meet the requirements, the sub-microgrid corresponding to the compensator with a smaller current compensation coefficient in the current state will exit the current compensation mode and enter the voltage control mode, and re-perform voltage quality verification until the voltage quality meets the requirements.

[0047] 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, wherein the processor implements the steps of the above-mentioned multi-region microgrid voltage coordination control method when executing the computer program.

[0048] 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 multi-region microgrid voltage coordination control method are implemented.

[0049] Beneficial Effects

[0050] 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 a dual-mode control method of current compensation mode and voltage control mode. In order to realize the above mode switching control and coordinated compensation of each sub-microgrid, the present invention regulates each sub-microgrid through a central controller. When regulating, a droop curve of power and compensation coefficient is first established, and the compensation ratio is obtained according to the actual working situation, and it is adjusted to obtain the compensation coefficient ratio. The compensation ratio is used to distribute harmonic compensation to each sub-microgrid in the current mode and select the sub-microgrid working in the voltage control mode. In this way, the original grid-connected inverter can participate in voltage quality management without adding new voltage support equipment, and retain its new energy grid-connected capability, while realizing reactive compensation and harmonic management, and can reasonably allocate compensation for different grid-connected voltage requirements of multiple sub-microgrids, and reasonably utilize the remaining capacity of the grid-connected inverter of the distributed multi-sub-microgrid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is an overall control structure block diagram of the multi-region microgrid voltage coordination control method according to the first embodiment of the present invention;

[0052] Figure 2 is a flow chart of a multi-region microgrid voltage coordination control method according to a first embodiment of the present invention;

[0053] Figure 3 is a droop curve diagram in the first embodiment of the present invention;

[0054] Figure 4 is a voltage curve diagram when the mode is switched in the first embodiment of the present invention;

[0055] Figure 5 : is a voltage waveform diagram of the sub-microgrid grid connection point in the first embodiment of the present invention;

[0056] Figure 6 This is a current compensation diagram of a sub-microgrid with a smaller capacity in the first embodiment of the present invention. DETAILED DESCRIPTION

[0057] 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.

[0058] The first embodiment of the present invention relates to a multi-region microgrid voltage coordination control method, the overall control structure of the method is as follows: Figure 1As shown, it includes a current compensation mode and a voltage control mode. In order to realize the switching control of the above two modes and the coordinated compensation of each sub-microgrid, this embodiment also proposes a method for regulating each sub-microgrid by relying on a central controller, such as Figure 2 As shown, the specific steps include:

[0059] Step 1: Design the current compensation mode and voltage control mode.

[0060] The current compensation mode of this embodiment requires both photovoltaic grid connection and current harmonic compensation. This mode needs to be activated when nonlinear loads are serious. This mode retains most of the grid-connected capacity and is suitable for sub-microgrids with large distributed generation power. Therefore, the current compensation mode of this embodiment is as follows:

[0061] In order to obtain the fundamental active component, the three-phase voltage value u of the input bus common coupling point (PCC) is abc and the current value i abc Transform from the stationary coordinate system abc to the dq rotating coordinate system, the transformation matrix C 3z / 2x It can be expressed as:

[0062]

[0063] The voltage component u obtained after coordinate transformation d ,u q and the current component i d ,i q Perform low-pass filtering and convert the result of low-pass filtering into Perform pq transformation to obtain the positive sequence fundamental active current component;

[0064] The positive sequence fundamental active current component is transformed from the dq rotating coordinate system to the stationary coordinate system abc, that is, the positive sequence fundamental active current component is input into the transformation matrix C 3z / 2x The inverse matrix of is obtained to obtain the fundamental current;

[0065] Subtract the three-phase current value i of the bus common coupling point from the obtained fundamental current abc , and get the compensation current i t ;

[0066] The grid-connected control adopts PQ control, and its output is the grid-connected reference current. b With compensation current i t Add together to get the total input reference current i ref , the total reference current i ref Input to the PR controller and generate PWM wave.

[0067] The voltage control mode of this embodiment works under the condition of voltage fluctuation at the grid connection point, which can suppress voltage fluctuation, but it is impossible to connect distributed power generation to the grid. It is suitable for sub-microgrids with relatively small distributed power generation to work in this mode. Therefore, the voltage control mode of this embodiment is specifically as follows: an AC voltage amplitude outer loop is added to the voltage control structure, and the reactive current reference value is adjusted through a voltage closed loop; under this voltage control mode, the voltage control on the DC side of the capacitor in the traditional voltage control structure is retained, and the inner loop is current control. The output of the AC voltage amplitude outer loop is used as the given value of the q-axis output current inner loop, and its control equation is:

[0068] i oqref =k tp (U tref -U t )+k ti ∫(U tref -U t )dt

[0069] Among them, i oqref is the output of the AC voltage amplitude outer loop, k tp and k ti are the proportional coefficient and integral coefficient of the PI controller in the AC voltage amplitude outer loop respectively; U tref is the reference value of the AC voltage amplitude, U t is the voltage amplitude of PCC.

[0070] Step 2: Analyze the power quality requirements of each sub-microgrid, adopt the voltage control module for the sub-microgrid whose power quality requirements meet the preset requirements, and adopt the current compensation mode for the sub-microgrid whose power quality requirements do not meet the preset requirements.

[0071] In this step, the power quality requirements include voltage quality indicators and current quality indicators, wherein the voltage quality indicators include: voltage maximum allowable deviation indicator ΔU (%), voltage harmonic distortion rate, voltage stability margin; current quality indicators include: current harmonics caused by unbalanced load, etc. Different power quality requirements exist for different sub-microgrids, and the initial control mode of each compensator is preliminarily determined. In this implementation, the voltage control mode is adopted for the microgrid with higher voltage quality requirements, and the current compensation mode is adopted for the sub-microgrid with lower voltage requirements.

[0072] Step 3: Use the dual-mode operation switching control algorithm to realize the switching control of the voltage control module and the current compensation mode as well as the coordinated compensation of each sub-microgrid.

[0073] The control algorithm for dual-mode operation switching in this step is as follows:

[0074] First, establish the droop curve of the microgrid power generation and current compensation coefficient (see Figure 3), and the current compensation coefficient is obtained according to the actual working conditions. Among them, the current compensation coefficient is calculated by α x =1-Pk i Calculated, where α x is the current compensation coefficient, P is the power generation of the microgrid, k i is the droop coefficient determined according to the sub-microgrid.

[0075] In order to ensure that the sum of the current compensation coefficients of each sub-microgrid is 1, it is necessary to adjust the current compensation coefficients to obtain the compensation coefficient ratio. The adjustment formula is:

[0076]

[0077] in, is the compensation coefficient ratio, α x is the current compensation coefficient, and n is the number of sub-microgrids working in the current compensation mode.

[0078] Then, the harmonic compensation distribution of each sub-microgrid in the current mode is carried out through the compensation coefficient ratio.

[0079] Afterwards, according to the detected voltage quality, a sub-microgrid that enters the voltage control mode is selected from the sub-microgrids operating in the current compensation mode, specifically:

[0080] Detecting voltage quality, when it is detected that the voltage quality does not meet the requirements, selecting the sub-microgrid corresponding to the compensator with the smallest current compensation coefficient to exit the current compensation mode and enter the voltage control mode;

[0081] Perform voltage quality verification. If the voltage quality meets the requirements, operate according to the current state. If the voltage quality does not meet the requirements, the sub-microgrid corresponding to the compensator with a smaller current compensation coefficient in the current state will exit the current compensation mode and enter the voltage control mode, and re-perform voltage quality verification until the voltage quality meets the requirements.

[0082] Finally, the control parameters of each sub-microgrid are adjusted to meet the coordinated control of power quality of each sub-microgrid.

[0083] The present invention is further illustrated by a specific embodiment below.

[0084] In this embodiment, the number of sub-microgrids n is set to 2. Among them, the voltage quality indicators of sub-microgrid 1 include: the maximum allowable voltage deviation indicator ΔU1 (%) = ±10%, the voltage harmonic distortion rate ≤5%, and the voltage stability margin is guaranteed by the load change of ±20% to ensure static stability; the current quality indicators include: the current harmonics caused by unbalanced load ≤5%. The voltage quality indicators of sub-microgrid 2 include: the maximum allowable voltage deviation indicator ΔU1 (%) = ±8%, the voltage harmonic distortion rate ≤4%, and the voltage stability margin is guaranteed by the load change of ±25% to ensure static stability; the current quality indicators include: the current harmonics caused by unbalanced load ≤5%. In order to ensure that each sub-microgrid can initially meet its own power quality requirements, the initial modes of sub-microgrid 1 and sub-microgrid 2 in this embodiment are both set in the current compensation mode.

[0085] The current compensation mode in this embodiment is as follows:

[0086] In order to obtain the fundamental active component, the input bus PCC three-phase voltage value and current value Transform from the stationary coordinate system abc to the dq rotating coordinate system. The initial phase ω=2πf,f=50Hz,so the transformation matrix is ​​C 3z / 2x for:

[0087]

[0088] The voltage component u obtained after coordinate transformation d ,u q and the current component i d ,i q Perform low-pass filtering and convert the result of low-pass filtering into Perform pq transformation to obtain the positive-sequence fundamental active current component.

[0089] The positive sequence fundamental active current component is transformed from the dq rotating coordinate system to the stationary coordinate system abc, that is, the positive sequence fundamental active current component is input into the transformation matrix C 3z / 2x The inverse matrix of is used to obtain the fundamental current.

[0090] Subtract the three-phase current value i of the bus common coupling point from the obtained fundamental current abc , and get the compensation current i t .

[0091] The grid-connected control adopts PQ control, and its output is the grid-connected reference current. b With compensation current i t Add together to get the total input reference current i ref , the total reference current i ref Input to the PR controller and generate PWM wave.

[0092] The voltage control mode in this embodiment is: adding an AC voltage amplitude outer loop to the voltage control structure, and adjusting the reactive current reference value through a voltage closed loop. The control equation of the AC voltage amplitude outer loop is:

[0093] i oqref =k tp (U tref -U t )+k ti ∫(U tref -U t )dt

[0094] Where: k tp =150 and k ti =5 are the proportional and integral coefficients of the AC voltage amplitude outer loop PI controller respectively; U tref =380V is the reference value of AC voltage, U t is the PCC voltage amplitude.

[0095] Figure 3 The droop curve of compensation coefficient and online power. Since this embodiment only considers two sub-microgrids, the capacities of the two sub-microgrids are: S1 = 9.5 kVA, S2 = 2.4 kVA, and the maximum online power P 1max =8.8kW,P 2max =2.2kW.

[0096] Based on the remaining capacity of the grid-connected inverter, the size of the distributed grid-connected power, and the bus voltage and current quality evaluation indicators, a control algorithm for dual-mode operation switching is established:

[0097] First, a droop curve of the microgrid power generation and compensation coefficient is established, and the compensation ratio is obtained based on the actual working conditions. The compensation coefficient and the sub-microgrid grid power satisfy the following linear relationship:

[0098] α1=1-P1k1

[0099] α2=1-P2k2

[0100] Where: α1 is the current compensation coefficient of sub-microgrid 1, α2 is the current compensation coefficient of sub-microgrid 2. P1≤8.8kW is the on-grid power of sub-microgrid 1, P2≤2.2kW is the on-grid power of sub-microgrid 2, k1=1 / P 1max , k2=1 / P 2max are the droop coefficients of sub-microgrid 1 and sub-microgrid 2 respectively.

[0101] In order to satisfy the requirement that the sum of the compensation coefficients of each sub-microgrid is 1, the current compensation coefficients of sub-microgrid 1 and sub-microgrid 2 obtained in the above formula are adjusted to obtain the compensation coefficient ratio, and the harmonic compensation distribution of each sub-microgrid in the current mode is performed through the compensation coefficient ratio. The adjustment formula is:

[0102]

[0103] and It is the compensation coefficient of the input controller after tuning.

[0104] Detect voltage and current quality. Initially, all compensators work in current compensation mode. When it is detected that the voltage quality does not meet the requirements, the sub-microgrid corresponding to the compensator with the smallest compensation coefficient is selected to exit the current compensation mode and enter the voltage control mode. Then perform voltage quality verification. If the voltage quality meets the requirements, operate according to the current state. If the voltage quality does not meet the requirements, the sub-microgrid corresponding to the compensator with a smaller current compensation coefficient in the current state exits the current compensation mode and enters the voltage control mode, and re-verifies the voltage quality until the voltage quality meets the requirements.

[0105] like Figure 4 As shown in the figure, when the voltage exceeds the limit, the sub-microgrid with smaller capacity exits the current compensation mode and enters the voltage control mode. At this time, the total online active power is reduced, and the sub-microgrid with smaller capacity enters the voltage control mode. Figure 5 This is the voltage waveform of the sub-microgrid grid-connected point. When a load disturbance is added at t = 0.3 seconds, the voltage first exceeds the limit but is adjusted back to normal after half a cycle. Figure 6 This is the current compensation diagram of a sub-microgrid with a smaller capacity. At t=0.3 seconds, the sub-microgrid no longer compensates the current.

[0106] It can be seen that by using the voltage coordination control implemented in this way, the original grid-connected inverter can participate in voltage quality management without adding new voltage support equipment, and retain its new energy grid-connected capability, while achieving reactive power compensation and harmonic management, and being able to reasonably allocate compensation amounts for different grid-connected voltage requirements of multiple microgrids, thereby reasonably utilizing the remaining capacity of the grid-connected inverter of the distributed multi-microgrid system.

[0107] A second embodiment of the present invention relates to a multi-region microgrid voltage coordination control device, comprising:

[0108] Design module, used to design current compensation mode and voltage control mode;

[0109] An initial control mode determination module is used to analyze the power quality requirements of each sub-microgrid, and adopt the voltage control module for the sub-microgrid whose power quality requirements meet the preset requirements, and adopt the current compensation mode for the sub-microgrid whose power quality requirements do not meet the preset requirements;

[0110] The control module is used to implement the switching control of the voltage control module and the current compensation mode and the coordinated compensation of each sub-microgrid by adopting the control algorithm of the dual-mode operation switching, wherein the control algorithm of the dual-mode operation switching is specifically:

[0111] Establish the droop curve of the sub-microgrid power generation and current compensation coefficient, and obtain the current compensation coefficient based on the actual working conditions;

[0112] The obtained current compensation coefficient is adjusted to obtain the compensation coefficient ratio;

[0113] The harmonic compensation of each sub-microgrid working in the current compensation mode is distributed through the compensation coefficient ratio;

[0114] According to the detected voltage quality, a sub-microgrid that enters a voltage control mode is selected from the sub-microgrids operating in the current compensation mode.

[0115] The current compensation mode is specifically:

[0116] The three-phase voltage and current values ​​of the input bus common coupling point are transformed from the stationary coordinate system abc to the dq rotating coordinate system;

[0117] The voltage component and the current component obtained after the coordinate transformation are subjected to low-pass filtering, and the result after the low-pass filtering is subjected to pq transformation to obtain the positive sequence fundamental wave active current component;

[0118] The positive sequence fundamental active current component is transformed from the dq rotating coordinate system to the stationary coordinate system abc to obtain the fundamental current;

[0119] The obtained fundamental current is subtracted from the three-phase current value of the input bus common coupling point to obtain the compensation current;

[0120] The grid-connected control adopts PQ control, and its output is the grid-connected reference current. The grid-connected reference current is added to the compensation current to obtain the input total reference current, and the input total reference current is input into the PR controller to generate a PWM wave.

[0121] The voltage control mode is specifically as follows: adding an AC voltage amplitude outer loop to the voltage control structure, and adjusting the reactive current reference value through a voltage closed loop; the output of the AC voltage amplitude outer loop is used as a given value of the q-axis output current inner loop.

[0122] The control equation of the AC voltage amplitude outer loop is expressed as: oqref =ktp (U tref -U t )+k ti ∫(U tref -U t )dt, where i oqref is the output of the AC voltage amplitude outer loop, k tp and k ti are the proportional coefficient and integral coefficient of the PI controller in the AC voltage amplitude outer loop respectively; U tref is the reference value of the AC voltage amplitude, U t is the voltage amplitude at the bus common coupling point.

[0123] The current compensation coefficient is α x =1-Pk i Calculated, where α x is the current compensation coefficient, P is the power generation of the microgrid, k i is the droop coefficient determined according to the sub-microgrid.

[0124] When adjusting the obtained current compensation coefficient, use To adjust, is the compensation coefficient ratio, α x is the current compensation coefficient, and n is the number of sub-microgrids working in the current compensation mode.

[0125] The selecting, according to the detected voltage quality, a sub-microgrid that enters the voltage control mode from the sub-microgrids operating in the current compensation mode is specifically:

[0126] Detecting voltage quality, when it is detected that the voltage quality does not meet the requirements, selecting the sub-microgrid corresponding to the compensator with the smallest current compensation coefficient to exit the current compensation mode and enter the voltage control mode;

[0127] Perform voltage quality verification. If the voltage quality meets the requirements, operate according to the current state. If the voltage quality does not meet the requirements, the sub-microgrid corresponding to the compensator with a smaller current compensation coefficient in the current state will exit the current compensation mode and enter the voltage control mode, and re-perform voltage quality verification until the voltage quality meets the requirements.

[0128] A 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 multi-regional microgrid voltage coordination control method of the first embodiment when executing the computer program.

[0129] A fourth embodiment of the present invention relates to a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the multi-region microgrid voltage coordination control method of the first embodiment.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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 multi-region microgrid voltage coordination control method, characterized in that: The following steps are involved: Design current compensation mode and voltage control mode; Analyze the power quality requirements of each sub-microgrid, adopt the voltage control module for the sub-microgrid whose power quality requirements meet the preset requirements, and adopt the current compensation mode for the sub-microgrid whose power quality requirements do not meet the preset requirements; The control algorithm of dual-mode operation switching is adopted to realize the switching control of the voltage control module and the current compensation mode and the coordinated compensation of each sub-microgrid, wherein the control algorithm of the dual-mode operation switching is specifically as follows: Establish the droop curve of the sub-microgrid power generation and current compensation coefficient, and obtain the current compensation coefficient based on the actual working conditions; The obtained current compensation coefficient is adjusted to obtain the compensation coefficient ratio; The harmonic compensation of each sub-microgrid working in the current compensation mode is distributed through the compensation coefficient ratio; According to the detected voltage quality, a sub-microgrid that enters a voltage control mode is selected from the sub-microgrids operating in the current compensation mode.

2. The multi-region microgrid voltage coordination control method according to claim 1, characterized in that: The current compensation mode is specifically: The three-phase voltage and current values ​​of the input bus common coupling point are transformed from the stationary coordinate system abc to the dq rotating coordinate system; The voltage component and the current component obtained after the coordinate transformation are subjected to low-pass filtering, and the result after the low-pass filtering is subjected to pq transformation to obtain the positive sequence fundamental wave active current component; The positive sequence fundamental active current component is transformed from the dq rotating coordinate system to the stationary coordinate system abc to obtain the fundamental current; The obtained fundamental current is subtracted from the three-phase current value of the input bus common coupling point to obtain the compensation current; The grid-connected control adopts PQ control, and its output is the grid-connected reference current. The grid-connected reference current is added to the compensation current to obtain the input total reference current, and the input total reference current is input into the PR controller to generate a PWM wave.

3. The multi-region microgrid voltage coordination control method according to claim 1, characterized in that: The voltage control mode is specifically as follows: adding an AC voltage amplitude outer loop to the voltage control structure, and adjusting the reactive current reference value through a voltage closed loop; the output of the AC voltage amplitude outer loop is used as a given value of the q-axis output current inner loop.

4. The multi-region microgrid voltage coordination control method according to claim 3 is characterized in that: The control equation of the AC voltage amplitude outer loop is expressed as: oqref =k tp (U tref -U t )+k ti ∫(U tref -U t )dt, where i oqref is the output of the AC voltage amplitude outer loop, k tp and k ti are the proportional coefficient and integral coefficient of the PI controller in the AC voltage amplitude outer loop respectively; U tref is the reference value of the AC voltage amplitude, U t is the voltage amplitude at the bus common coupling point.

5. The multi-region microgrid voltage coordination control method according to claim 1, characterized in that: The current compensation coefficient is α x =1-Pk i Calculated, where α x is the current compensation coefficient, P is the power generation of the microgrid, k i is the droop coefficient determined according to the sub-microgrid.

6. The multi-region microgrid voltage coordination control method according to claim 1, characterized in that: When adjusting the obtained current compensation coefficient, use To adjust, is the compensation coefficient ratio, α x is the current compensation coefficient, and n is the number of sub-microgrids working in the current compensation mode.

7. The multi-region microgrid voltage coordination control method according to claim 1, characterized in that: The selecting, according to the detected voltage quality, a sub-microgrid that enters the voltage control mode from the sub-microgrids operating in the current compensation mode is specifically: Detecting voltage quality, when it is detected that the voltage quality does not meet the requirements, selecting the sub-microgrid corresponding to the compensator with the smallest current compensation coefficient to exit the current compensation mode and enter the voltage control mode; Perform voltage quality verification. If the voltage quality meets the requirements, operate according to the current state. If the voltage quality does not meet the requirements, the sub-microgrid corresponding to the compensator with a smaller current compensation coefficient in the current state will exit the current compensation mode and enter the voltage control mode, and re-perform voltage quality verification until the voltage quality meets the requirements.

8. A multi-region microgrid voltage coordination control device, characterized in that: include: Design module, used to design current compensation mode and voltage control mode; An initial control mode determination module is used to analyze the power quality requirements of each sub-microgrid, and adopt the voltage control module for the sub-microgrid whose power quality requirements meet the preset requirements, and adopt the current compensation mode for the sub-microgrid whose power quality requirements do not meet the preset requirements; A control module is used to implement the switching control of the voltage control module and the current compensation mode and the coordinated compensation of each sub-microgrid by adopting a control algorithm for dual-mode operation switching, wherein the control algorithm for dual-mode operation switching is specifically as follows: establishing a droop curve of the sub-microgrid power generation power and the current compensation coefficient, and obtaining the current compensation coefficient according to the actual working conditions; The obtained current compensation coefficient is adjusted to obtain the compensation coefficient ratio; The harmonic compensation of each sub-microgrid working in the current compensation mode is distributed through the compensation coefficient ratio; According to the detected voltage quality, a sub-microgrid that enters a voltage control mode is selected from the sub-microgrids operating in the current compensation mode.

9. The multi-region microgrid voltage coordination control device according to claim 8, characterized in that: The current compensation mode is specifically: The three-phase voltage and current values ​​of the input bus common coupling point are transformed from the stationary coordinate system abc to the dq rotating coordinate system; The voltage component and the current component obtained after the coordinate transformation are subjected to low-pass filtering, and the result after the low-pass filtering is subjected to pq transformation to obtain the positive sequence fundamental wave active current component; The positive sequence fundamental active current component is transformed from the dq rotating coordinate system to the stationary coordinate system abc to obtain the fundamental current; The obtained fundamental current is subtracted from the three-phase current value of the input bus common coupling point to obtain the compensation current; The grid-connected control adopts PQ control, and its output is the grid-connected reference current. The grid-connected reference current is added to the compensation current to obtain the input total reference current, and the input total reference current is input into the PR controller to generate a PWM wave.

10. The multi-region microgrid voltage coordination control device according to claim 8, characterized in that: The voltage control mode is specifically as follows: adding an AC voltage amplitude outer loop to the voltage control structure, and adjusting the reactive current reference value through a voltage closed loop; the output of the AC voltage amplitude outer loop is used as a given value of the q-axis output current inner loop.

11. The multi-region microgrid voltage coordination control device according to claim 10, characterized in that: The control equation of the AC voltage amplitude outer loop is expressed as: oqref =k tp (U tref -U t )+k ti ∫(U tref -U t )dt, where i oqref is the output of the AC voltage amplitude outer loop, k tp and k ti are the proportional coefficient and integral coefficient of the PI controller in the AC voltage amplitude outer loop respectively; U tref is the reference value of the AC voltage amplitude, U t is the voltage amplitude at the bus common coupling point.

12. The multi-region microgrid voltage coordination control device according to claim 8, characterized in that: The current compensation coefficient is α x =1-Pk i Calculated, where α x is the current compensation coefficient, P is the power generation of the microgrid, k i is the droop coefficient determined according to the sub-microgrid.

13. The multi-region microgrid voltage coordination control device according to claim 8, characterized in that: When adjusting the obtained current compensation coefficient, use Adjustment is performed, where α~ x is the compensation coefficient ratio, α x is the current compensation coefficient, and n is the number of sub-microgrids working in the current compensation mode.

14. The multi-region microgrid voltage coordination control device according to claim 8, characterized in that: The selecting, according to the detected voltage quality, a sub-microgrid that enters the voltage control mode from the sub-microgrids operating in the current compensation mode is specifically: Detecting voltage quality, when it is detected that the voltage quality does not meet the requirements, selecting the sub-microgrid corresponding to the compensator with the smallest current compensation coefficient to exit the current compensation mode and enter the voltage control mode; Perform voltage quality verification. If the voltage quality meets the requirements, operate according to the current state. If the voltage quality does not meet the requirements, the sub-microgrid corresponding to the compensator with a smaller current compensation coefficient in the current state will exit the current compensation mode and enter the voltage control mode, and re-perform voltage quality verification until the voltage quality meets the requirements.

15. 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 multi-region microgrid voltage coordination control method as described in any one of claims 1-7 are implemented.

16. 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 multi-region microgrid voltage coordination control method as described in any one of claims 1-7 are implemented.

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