Low-voltage area phase-separated output power regulation system, regulation method and storage medium

Abstract

The embodiment of the application discloses a low-voltage area phase output power adjusting system, an adjusting method and a storage medium. The system comprises an adjusting power supply, a phase power adjusting module, a sub-controller, a main controller, the adjusting power supply is connected with the phase power adjusting module, the total power P of the adjusting power supply satisfies the following formula relationship: wherein Pt is the power required to satisfy the three-phase current imbalance regulation and control of a distribution transformer, P G1 、 P G2 … P Gn is the power emitted by each adjusting power supply to compensate for the three-phase current imbalance of the area; the phase power adjusting module is connected with the three-phase lines and the neutral line N of the area A, B and C; the sub-controller is connected with the adjusting power supply, and the sub-controller communicates with the main controller to control the power emitted by each adjusting power supply to compensate for the three-phase current imbalance of the area. Multiple distributed power supplies are cooperatively adjusted to realize accurate management of the three-phase imbalance of the area, reduce line loss and improve power quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system electric energy quality control, and particularly relates to a low-voltage area phase output power regulation system, a regulation method and a storage medium. BACKGROUND

[0002] High-quality electric energy quality is the premise of guaranteeing high-quality economic power supply for users. With the development of social economy and the improvement of people's living standards, production enterprises and residents have higher and higher requirements for electric energy quality. The low-voltage area of the domestic distribution network is supplied with three-phase four-wire power supply. Due to the disorderly access of single-phase loads and the inconsistency of power consumption time, the three-phase of the distribution network system is generally unbalanced. At present, a large number of distributed low-voltage photovoltaic power is connected to the distribution network area, which further aggravates the three-phase imbalance of the area, and problems such as low voltage and increased line loss are increasingly prominent. In severe cases, it may cause single-phase overload burning of distribution transformers and affect the normal production and living power consumption of residents.

[0003] At present, for the problem of three-phase imbalance of the distribution network, the patent "Low-voltage power grid three-phase unbalanced current compensation method and device" (CN105406494A) proposes a method of using a single-phase APF active filter to output a current value equal in size and opposite in direction to the phase current to compensate for the zero sequence current. The patent "Low-voltage line three-phase imbalance treatment device based on three-phase four-wire photovoltaic inverter" (CN21404544U) proposes a method of using a special photovoltaic inverter of three-phase four-wire system to connect the light phase of the power grid through the input switch and connect the heavy phase of the power grid through the output switch, adjust the power balance between the light load and the heavy load of the two phases, and realize three-phase imbalance treatment. However, the above methods have a serious drawback: they cannot completely suppress the negative sequence and zero sequence current on the line to achieve full compensation of the unbalanced current. They can only reduce the system imbalance to a certain extent and cannot completely achieve three-phase balance of the distribution transformer. SUMMARY

[0004] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the specific embodiment section. The summary section of the present application does not mean to attempt to limit the key features and necessary technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0005] In order to overcome the defects of the prior art and effectively solve the problem of three-phase imbalance of the distribution network, in a first aspect, the present application proposes a low-voltage area phase output power regulation system, which comprises:

[0006] a regulation power supply 10, a phase power regulation module 20, a sub-controller 30, and a main controller 40;

[0007] The regulation power supply is connected with the phase power regulation module, and the total power P of the regulation power supply satisfies the following relationship:

[0008]

[0009] Wherein, Pt is the power required to meet the three-phase current imbalance regulation of distribution transformer, P G1 , P G2 ...P Gn is the power emitted by each said regulating power supply to compensate for the three-phase current imbalance of the transformer area;

[0010] The said split-phase power regulation module is connected with the three-phase lines A, B and C and the neutral line N of the transformer area;

[0011] The said split controller is connected with the said regulating power supply, and the said split controller communicates with the said main controller to control the power emitted by each said regulating power supply to compensate for the three-phase current imbalance of the transformer area.

[0012] Optionally, the said split-phase power regulation module comprises a first filter capacitor, a second filter capacitor, a three-phase reactor and a three-phase full-bridge inverter;

[0013] The said first filter capacitor and the said second filter capacitor are connected with the power grid between the neutral line of the power grid and the said three-phase full-bridge inverter, and the said three-phase reactor is connected between the said three-phase full-bridge inverter and the three-phase lines of the power grid;

[0014] Wherein, the inductance values of the said first filter capacitor, the said second filter capacitor and the said three-phase reactor are determined by the capacity and the filtering effect.

[0015] Optionally, the said split controller communicates with the said main controller by wireless or carrier wave mode, the said split controller is electrically connected with the said split-phase power regulation module, used to collect the power and voltage of each phase of the corresponding split-phase power regulation module and upload to the said main controller, and the said split controller is used to issue the control amount calculated by the said main controller to the corresponding split-phase power regulation module to control the said split-phase power regulation module to output the regulating power corresponding to the said main controller.

[0016] Optionally, the said main controller is used to collect the voltage and current of the A phase, B phase and C phase of the transformer area, and calculate the three-phase power of the A phase, B phase and C phase that the split-phase power regulation module should output according to the voltage and current of the A phase, B phase and C phase.

[0017] Wherein, the power calculation formulas of the A phase, B phase and C phase are as follows:

[0018] P a = u a *i a

[0019] P b = u b *i b

[0020] P c = u c *i c

[0021] In the formula, Pa is the phase A power of the transformer area, Ua is the phase A voltage of the transformer area, and ia is the phase A current of the transformer area, Pb is the phase B power of the transformer area, Ub is the phase B voltage of the transformer area, and ib is the phase B current of the transformer area, Pc is the phase C power of the transformer area, Uc is the phase C voltage of the transformer area, and ic is the phase C current of the transformer area. b = u b *i b *i b = u b *i b *i

[0022] The power calculation formula of the jth regulating power source after the node i and required to supplement the three-phase transformer areas A, B and C is as follows:

[0023]

[0024]

[0025]

[0026] In the formula, n is the number of the regulating power sources participating in the regulation.

[0027] Optionally, the split-phase power regulation module is configured to ensure that the voltage difference between the nodes is minimum, and the optimal output values Pxa, Pxb, Pxc, Qxa, Qxb and Qxc of the split-phase power regulation module are obtained based on a PSO optimization algorithm.

[0028] The unbalance degree formula corresponding to the PSO optimization algorithm is as follows:

[0029] (Pa+Pb+Pc-(Pxa+Pxb+Pxc)) / 3=K1

[0030] (|Pa-Pxa-K1|+|Pb-Pxb-K1|+|Pc-Pxc-K1|) / 3*K1=A

[0031] The constraint condition corresponding to the PSO optimization algorithm is as follows:

[0032] Pxa+Pxb+Pxc=Ppv

[0033] Pxa+Pxb+Pxc+Qxa≤Svsi

[0034] A<5%

[0035] The target function corresponding to the PSO optimization algorithm is as follows:

[0036]

[0037]

[0038] In the formula, △U mj is the voltage difference between node m and node m-1 after the distributed power supply and energy storage participate in unbalanced regulation, k is the total number of regulating power supply accessed by the transformer area, Pi is the power of each node in the transformer area after node i, r is the resistance corresponding to the unit length line of the transformer area, x is the reactance corresponding to the unit length line of the transformer area, and lm is the line length from the head of the transformer area to node i.

[0039] Optionally, the unbalanced reference current I a_ref , I b_ref and I c_ref of the output of the split-phase power regulation module are determined by the following formula:

[0040]

[0041]

[0042]

[0043] In the formula, is the negative sequence current and zero sequence current of the unbalanced current sequence component required to be output by the split-phase power regulation module, I a * , I b * , I c * is the filter capacitor voltage control component of the split-phase power regulation module.

[0044] Optionally, the filter capacitor voltage control component of the split-phase power regulation module is I a * , I b * , I c * obtained by the following method:

[0045] obtain the voltage difference between the voltage U dc and the voltage U dc_ref after the first filter capacitor and the second filter capacitor are connected in series;

[0046] The voltage difference is output as the d-axis active component of dq / abc conversion after PI controller;

[0047] set the q-axis reactive component of dq / abc conversion to 0;

[0048] The capacitor voltage control component I is obtained after dq / abc transformation. a * I b * I c * .

[0049] Optionally, the unbalanced current output by the phase-splitting power regulation module is determined by the following formula:

[0050] I aj =|P axj | / u aj

[0051] I bj =|P bxj | / u bj

[0052] I cj =|P cxj | / u cj

[0053] In the formula, u aj u bj u cj Let A, B, and C be the three-phase voltages at node j, respectively.

[0054] In a second aspect, the present invention also proposes a method for adjusting the phase output power of a low-voltage station, for use in the system described in any one of the first aspects, comprising: steps S110-S170;

[0055] S110, Detect three-phase imbalance;

[0056] S120. If the three-phase imbalance does not reach the starting value, calculate the power that each phase of the transformer area needs to compensate.

[0057] S130. Determine the regulating power sources that need to participate in the imbalance regulation of the distribution area, wherein the regulating power sources include distributed photovoltaic power and distributed small energy storage power sources in the distribution area.

[0058] S140. Calculate the unbalanced adjustment power required to be output by each phase power regulation module, and determine the three-phase compensation reference current I of the phase power regulation module. a_ref I b_ref I c_ref ;

[0059] S150, The converter hysteresis control of the phase power regulation module tracks the current reference value I. a_ref I b_ref I c_ref Obtain the actual compensation current I of the phase output module converter.oa I ob I oc ;

[0060] S160. Detect whether the change in the three-phase imbalance reaches the set offset value;

[0061] S170. If the set offset value is not reached, repeat steps S120 to S160.

[0062] Thirdly, the present invention also proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the low-voltage stage phase output power regulation method as described in the second aspect.

[0063] Implementing the embodiments of the present invention will have the following beneficial effects:

[0064] This invention controls multiple distributed regulating power sources in a distribution area, including distributed photovoltaic (PV) power and distributed small-scale energy storage power sources. While minimizing voltage deviation in the distribution area, it outputs unbalanced current. Multiple distributed power sources work together to precisely manage three-phase imbalance in the distribution area, reducing line losses and improving power quality. This invention achieves the reuse of optimal power generation from distributed PV power sources and three-phase imbalance compensation in the distribution area. When the three-phase load in the distribution area is balanced, the PV power source can supply power to the load as a normal power source, improving the system's economy. When the three-phase load in the distribution area is unbalanced, multiple distributed PV power sources can be controlled to output three-phase imbalance compensation power and power generation power, balancing three-phase imbalance management and PV grid connection. It provides an innovative method for distributed power sources to participate in distribution area power regulation, supporting the construction of new power systems. It realizes the management of three-phase imbalance in distribution transformers through multiple distributed PV power sources connected to the grid in separate phases. It proposes a mode of multi-distributed power source collaborative participation in distribution area regulation, providing a referenceable control technology for the power disturbance in the distribution area caused by the high penetration of distributed PV power sources in new power systems. Attached Figure Description

[0065] 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.

[0066] in:

[0067] Figure 1 This is a schematic diagram of a low-voltage stage phase output regulation system proposed in an embodiment of the present invention;

[0068] Figure 2This is a structural diagram of a phase-splitting power regulation module proposed in an embodiment of the present invention;

[0069] Figure 3 This is a control block diagram of an unbalanced current output method for a phase-splitting power regulation module proposed in an embodiment of the present invention;

[0070] Figure 4 An embodiment of the present invention presents a three-phase unbalanced current waveform diagram on the back-end load side;

[0071] Figure 5 An embodiment of the present invention presents a three-phase unbalanced current waveform diagram on the front-end load side;

[0072] Figure 6 An output current waveform diagram of a three-phase full-bridge inverter proposed in this embodiment of the invention;

[0073] Figure 7 An embodiment of the present invention presents a current waveform diagram of a transmission line before compensation;

[0074] Figure 8 An embodiment of the present invention presents a current waveform diagram of a compensated transmission line;

[0075] Figure 9 A schematic flowchart of a low-voltage station phase output power adjustment method proposed in this embodiment of the invention;

[0076] Figure 10 This is a schematic diagram of the structure of the low voltage ride-through control electronic device for a direct-drive fan provided in an embodiment of this application. Detailed Implementation

[0077] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0078] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The technical solutions of the embodiments of this application will now be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0079] Please see Figure 1 The low-voltage slab phase output power regulation system provided in this application embodiment includes:

[0080] Regulating power supply 10, phase power regulation module 20, sub-controller 30, main controller 40;

[0081] The regulating power supply 10 is connected to the phase-by-phase power regulating module 20, and the total power P of the regulating power supply satisfies the following relationship:

[0082]

[0083] Among them, P t To meet the power requirements for three-phase current imbalance control in distribution transformers, P G1 P G2 …P Gn The power generated by each of the regulating power supplies 10 in the transformer area to compensate for the imbalance of the three-phase current in the transformer area;

[0084] The phase power regulation module 20 is connected to the three-phase lines A, B, and C of the transformer area and the neutral line N.

[0085] The sub-controller 30 is connected to the regulating power supply 10, and the sub-controller 30 communicates with the main controller 10 to control the power output of the regulating power supply 10 to compensate for the three-phase current imbalance in the transformer area.

[0086] Specifically, such as Figure 1 As shown, the main controller 40 controls multiple phase-specific power regulation modules 20 to control the power input to the power grid of each regulating power source 10. The regulating power sources 10 include distributed photovoltaic power, distributed small hydropower, diesel generators, distributed energy storage, and other power sources.t To meet the power requirements for regulating the three-phase current imbalance of the distribution transformer, the regulating power supply compensates for the three-phase current imbalance by sending energy to the distribution area. This compensation can be done by the regulating power supply at some nodes or by all nodes. The sub-controller 30 is connected to the distribution area power grid via wires between the regulating power supply connection 10 and the distribution area power grid. The main controller 10 obtains the voltage and power measured at its connection point from the phase-specific power regulation module 20 and transmits this data. The main controller 10 then calculates and sends control quantities to the corresponding phase-specific power regulation module 20, thereby controlling the phase output module to output the corresponding regulated power.

[0087] In some embodiments, the phase power regulation module includes a first filter capacitor 21, a second filter capacitor 22, a three-phase reactor 23, and a three-phase full-bridge inverter 24;

[0088] The first filter capacitor 21 and the second filter capacitor 22 are connected to the power grid between the neutral line n of the power grid and the three-phase full-bridge inverter device 24, and the three-phase reactor 23 is connected between the three-phase full-bridge inverter 24 and the three-phase lines A, B, and C of the power grid.

[0089] The inductance values ​​of the first filter capacitor 21, the second filter capacitor 22, and the three-phase reactor 23 are determined by their capacity and filtering effect.

[0090] In some embodiments, the sub-controller 30 communicates with the main controller 40 wirelessly or via carrier wave. The sub-controller 30 is electrically connected to the phase power regulation module 20 and is used to collect the phase power and voltage of each phase at the grid connection point of the corresponding phase power regulation module 20 and upload them to the main controller 40. The sub-controller 30 also sends the control quantity calculated by the main controller 40 to the corresponding phase power regulation module 20 to control the phase power regulation module 20 to output the regulation power corresponding to the main controller.

[0091] In some implementations, the main controller 40 is used to collect the voltage and current of phases A, B and C of the transformer area, and calculate the three-phase power of phases A, B and C that the phase power regulation module should output based on the voltage and current of phases A, B and C.

[0092] The power calculation formulas for phases A, B, and C are as follows:

[0093] P a =u a *i a

[0094] P b =ub *i b

[0095] P c =u c *i c

[0096] In the formula, Pa is the power of phase A in the transformer substation, Ua is the voltage of phase A at the beginning of the transformer substation, ia is the current of phase A at the beginning of the transformer substation, and P... b For the power of phase B of the transformer substation, U b Phase B voltage at the first end of the transformer area, i b P is the phase B current at the beginning of the transformer substation. b For the power of phase B of the transformer substation, U b Phase B voltage at the first end of the transformer area, i b This refers to the B-phase current at the beginning of the transformer substation.

[0097] The formula for calculating the power that the j-th regulating power supply after node i needs to supplement to the three phases A, B, and C of the transformer area is as follows:

[0098]

[0099]

[0100]

[0101] In the formula, n represents the number of regulating power sources involved in the regulation.

[0102] In some implementations, the optimal output values ​​Pxa, Pxb, Pxc, Qxa, Qxb, and Qxc of the phase power regulation module are obtained based on the PSO optimization algorithm, while ensuring that the voltage difference between each node is minimized.

[0103] The imbalance formula corresponding to the PSO optimization algorithm is as follows:

[0104] (Pa+Pb+Pc-(Pxa+pxb+pxc)) / 3=K1;

[0105] (|Pa-Pxa-K1|+|pb-Pxb-K1|+|Pc-Pxc-K1|) / 3*K1=A;

[0106] The constraints corresponding to the PSO optimization algorithm are:

[0107] pxa+Pxb+Pxc=Ppv

[0108] Pxa+pxb+pxc+Qx≤Svsi

[0109] A<5%

[0110] The objective function corresponding to the PSO optimization algorithm is:

[0111]

[0112] In the formula, △U mj Let be the voltage difference between node m and node m-1 after distributed power sources and energy storage participate in imbalance regulation, k be the total number of regulating power sources connected to the transformer area, Pi be the power of each node in the transformer area after node i, r be the resistance corresponding to a unit length of line in the transformer area, x be the reactance corresponding to a unit length of line in the transformer area, and lm be the line length from the beginning of the transformer area to node i.

[0113] In some embodiments, the phase power regulation module 20, while ensuring that the distributed photovoltaic power source operates in the maximum power generation mode, outputs an unbalanced reference current I. a_ref I b_ref and I c_ref Determined by the following formula:

[0114]

[0115]

[0116]

[0117] In the formula, To calculate the negative sequence current and zero sequence current of the unbalanced current that the phase power regulation module 20 needs to output, I is used for decomposition calculation. a * I b * I c * This refers to the voltage control component of the filter capacitor in the phase-separated power regulation module.

[0118] In some embodiments, the voltage control component of the filter capacitor in the phase-splitting power regulation module 20 is I. a * I b * I c * Obtained through the following method:

[0119] Obtain the voltage U across the positive and negative terminals of the first and second filter capacitors connected in series. dc with U dc_ref The voltage difference;

[0120] The voltage difference is output as the d-axis active component of the dq / abc transformation after passing through the PI controller.

[0121] Set the reactive component of the q-axis of the dq / abc transformation to 0;

[0122] The capacitor voltage control component I is obtained after dq / abc transformation. a * I b * I c * .

[0123] Specifically, such as Figure 3 The diagram shown is a control block diagram of an unbalanced current output method for a phase-splitting power regulation module 20 according to an embodiment of the present invention. Firstly, the voltage U of the first filter capacitor... dc The voltage U of the second filter capacitor dc_ref The difference is calculated, and then the difference is output as the d-axis active component I of the dq / abc transformation after passing through a PI controller. d Transform dq / abc into the q-axis reactive component I. q Setting it to 0 will reduce the active power I d and reactive component I q After dq / abc transformation, the capacitor voltage control components Ia*, Ib*, and Ic* are obtained.

[0124] In some implementations, the unbalanced current output by the phase-splitting power regulation module 20 is determined by the following formula:

[0125] I aj =|P axj | / u aj

[0126] I bj =|P bxj | / u bj

[0127] I cj =|P cxj | / u cj

[0128] In the formula, u aj u bj u cj Let A, B, and C be the three-phase voltages at node j, respectively.

[0129] In summary, this invention controls multiple distributed power sources within a distribution area, outputting unbalanced current while minimizing voltage deviation. The coordinated regulation of multiple distributed power sources achieves precise management of three-phase imbalance in the distribution area, reducing line losses and improving power quality. This invention reuses the optimal power generation of distributed photovoltaic (PV) sources and the compensation for three-phase imbalance in the distribution area. When the three-phase load in the distribution area is balanced, the PV sources can power the load as normal power sources, improving the system's economy. When the three-phase load in the distribution area is unbalanced, multiple distributed PV sources can be controlled to output three-phase imbalance compensation power and power generation power, balancing the management of three-phase imbalance in the distribution area with PV grid connection. It provides an innovative method for distributed power sources to participate in distribution area power regulation, supporting the construction of new power systems. It realizes the management of three-phase imbalance in distribution transformers through multiple distributed PV sources connected to the grid in separate phases. It proposes a mode of coordinated participation of multiple distributed power sources in distribution area regulation, providing a referenceable control technology for the power disturbances in the distribution area caused by the high penetration of distributed PV sources in new power systems.

[0130] Please see Figures 4 to 9 , Figure 4 This is a waveform diagram of the three-phase unbalanced current on the load side. The waveform indicates that the three-phase current on the load side is in an unbalanced state. Figure 5 This is a waveform diagram of the three-phase unbalanced current on the front-end load side. The waveform indicates that the three-phase current on the front-end load side is in an unbalanced state. Figure 6 The waveform of the output current of the three-phase full-bridge inverter is shown. The waveform represents the compensation current output by the three-phase full-bridge inverter using the control method proposed in this invention. Figure 7 The waveform of the transmission line current before compensation is shown in the figure. As can be seen from the figure, the three-phase current of the transmission line is in an unbalanced state, with a current imbalance degree of 37.2%. Figure 8 The current waveform of the transmission line after compensation is shown in the figure. As can be seen from the figure, the three-phase current of the transmission line is in a balanced state, with a current imbalance of 1.8%. The current waveform also shows that after adopting the low-voltage distribution phase regulation system proposed in this invention, the current imbalance is significantly reduced, providing a referable control technology for the power disturbance in the distribution area caused by the high penetration of distributed photovoltaic power sources in the new power system.

[0131] like Figure 9 This application also proposes a power regulation method for distributed energy storage in conjunction with other methods, for use in the system described in the first aspect, characterized in that it includes:

[0132] S110, Detect three-phase imbalance;

[0133] S120. If the three-phase imbalance does not reach the starting value, calculate the power that each phase of the transformer area needs to compensate.

[0134] S130. Identify distributed photovoltaic systems in which the distribution area needs to participate in imbalance regulation;

[0135] S140. Calculate the unbalanced adjustment power required to be output by each phase power regulation module, and determine the three-phase compensation reference current I of the phase power regulation module. a_ref I b_ref I c_ref ;

[0136] S150, Through the converter hysteresis control of the phase power regulation module, the current reference value I is tracked. a_ref I b_ref I c_ref The actual compensation current I of the phase output module converter is obtained. oa I ob I oc ;

[0137] S160. Detect whether the change in the three-phase imbalance reaches the set offset value;

[0138] S170. If the set offset value is not reached, repeat steps S120 to S160.

[0139] like Figure 10 As shown, this application embodiment also provides an electronic device 300, including a memory 310, a processor 320, and a computer program 311 stored in the memory 320 and executable on the processor. When the processor 320 executes the computer program 311, it implements the steps of any of the above-described methods for controlling the outlet temperature of the trough solar collector field.

[0140] Since the electronic device described in this embodiment is the device used to implement the outlet temperature control device of a trough solar collector field in this application embodiment, those skilled in the art can understand the specific implementation method and various variations of the electronic device in this embodiment based on the method described in this application embodiment. Therefore, how the electronic device implements the method in this application embodiment will not be described in detail here. Any device used by those skilled in the art to implement the method in this application embodiment is within the scope of protection of this application.

[0141] In practical implementation, when the computer program 311 is executed by the processor, it can achieve the following: Figure 9 Any of the corresponding implementation methods in the embodiments.

[0142] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0143] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0144] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0145] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0146] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0147] This application also provides a computer program product, which includes computer software instructions that, when executed on a processing device, cause the processing device to perform actions such as... Figure 1 The flowchart of the low voltage ride-through control method for direct-drive fans in the corresponding embodiment.

[0148] A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0149] 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.

[0150] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0151] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0152] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0153] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0154] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A low-voltage sectional output power regulation system, characterized in that, include: Power supply adjustment, phase power regulation module, sub-controller, main controller; The regulating power supply is connected to the phase-by-phase power regulation module, and the total power P of the regulating power supply satisfies the following relationship: Wherein, Pt represents the power required to meet the three-phase current imbalance control of the distribution transformer. , … The power generated by each of the aforementioned regulating power supplies is to compensate for the three-phase current imbalance in the distribution area; The phase power regulation module is connected to the three-phase lines A, B, and C of the transformer area and the neutral line N. The sub-controller is connected to the regulating power supply, and the sub-controller communicates with the main controller to control the power output of each regulating power supply to compensate for the three-phase current imbalance in the distribution area. Among them, the phase-separated power regulation module ensures that the distributed photovoltaic power source operates in the maximum power generation mode, and the unbalanced reference current I output by the phase-separated power regulation module is... a_ref I b_ref and I c_ref Determined by the following formula: I a_ref = + + To* I b_ref = + + One* I c_ref = + + Ic* In the formula, , To calculate the negative-sequence current and zero-sequence current that need to be compensated, the unbalanced current sequence component of the phase-sequence power regulation module needs to be decomposed. a * I b * I c * This refers to the voltage control component of the filter capacitor in the phase-separated power regulation module.

2. The system as described in claim 1, characterized in that, The phase power regulation module includes a first filter capacitor, a second filter capacitor, a three-phase reactor, and a three-phase full-bridge inverter. The first filter capacitor and the second filter capacitor are connected to the power grid between the neutral line of the power grid and the three-phase full-bridge inverter device, and the three-phase reactor is connected between the three-phase full-bridge inverter and the three-phase line of the power grid. The inductance values ​​of the first filter capacitor, the second filter capacitor, and the three-phase reactor are determined by their capacity and filtering effect.

3. The system as described in claim 1, characterized in that, The sub-controller communicates with the main controller via wireless or carrier wave. The sub-controller is electrically connected to the phase power regulation module and is used to collect the phase power and voltage of each phase at the grid connection point of the corresponding phase power regulation module and upload them to the main controller. The sub-controller also sends the control quantity calculated by the main controller to the corresponding phase power regulation module to control the phase power regulation module to output the regulation power corresponding to the main controller.

4. The system as described in claim 1, characterized in that, The main controller is used to collect the voltage and current of phases A, B and C of the transformer area, and calculate the three-phase power of phases A, B and C that the phase power regulation module should output based on the voltage and current of phases A, B and C. The power calculation formulas for phases A, B, and C are as follows: In the formula, This refers to the power of phase A in the transformer substation. For the voltage of phase A at the first end of the transformer area, This refers to the A-phase current at the beginning of the transformer substation. This refers to the power of phase B in the transformer substation. For the voltage of phase B at the first end of the transformer area, This refers to the B-phase current at the beginning of the transformer substation. This refers to the C-phase power of the transformer substation. For the C-phase voltage at the first end of the transformer area, This refers to the C-phase current at the beginning of the transformer substation. The formula for calculating the power that the j-th regulating power supply after node i needs to supplement to the three phases A, B, and C of the transformer area is as follows: In the formula, n represents the number of regulating power sources involved in the regulation. Let be the power that the j-th regulating power supply after node i needs to supplement to phase A of the transformer area. Let be the power that the j-th regulating power supply after node i needs to supplement to phase B of the transformer area. This represents the power that the j-th regulating power supply after node i needs to supplement to phase C of the transformer area.

5. The system as described in claim 1, characterized in that, The optimal output values ​​Pxa, Pxb, Pxc, Qxa, Qxb, and Qxc of the phase power regulation module are obtained based on the PSO optimization algorithm, while ensuring that the voltage difference between each node is minimized. The imbalance formula corresponding to the PSO optimization algorithm is as follows: (Pa+Pb+Pc-( Pxa+Pxb+Pxc)) / 3=K1; (|Pa-Pxa-K1|+|Pb-Pxb-K1|+|Pc-Pxc-K1|) / 3*K1=A; The constraints corresponding to the PSO optimization algorithm are: pxa + Pxb + Pxc = Ppv Pxa + Pxb + Pxc + Qx ≤ Svsi A<5% The objective function corresponding to the PSO optimization algorithm is: In the formula, Let Pi be the voltage difference between node m and node m-1 after the regulating power supply participates in the imbalance regulation, k be the total number of regulating power supplies connected to the transformer area, Pi be the active power of the load of each node in the transformer area after node i, r be the resistance corresponding to the unit length of the line in the transformer area, x be the reactance corresponding to the unit length of the line in the transformer area, lm be the line length from the beginning of the transformer area to node i, Pxi be the total active power output of each regulating power supply after node i, Qi be the reactive power of the load of each node in the transformer area after node i, Ppv be the active power output of the regulating power supply, Qx be the reactive power output of the regulating power supply, and Svsi be the rated power of the regulating power supply. The regulating power source includes distributed photovoltaic power in the transformer substation and distributed small energy storage power.

6. The system as described in claim 2, characterized in that, The voltage control component of the filter capacitor in the phase power regulation module is I. a * I b * I c * Obtained through the following method: Obtain the voltage across the positive and negative terminals of the first and second filter capacitors connected in series. U dc and U dc_ref The voltage difference; The voltage difference is output as the d-axis active component of the dq / abc transformation after passing through the PI controller. Set the reactive component of the q-axis of the dq / abc transformation to 0; The capacitor voltage control component is obtained after dq / abc transformation. I a * , I b * , I c * 。 7. The system as described in claim 1, characterized in that, The unbalanced current output by the phase-splitting power regulation module is determined by the following formula: In the formula, u aj u bj u cj Let A, B, and C be the three-phase voltages at node j, respectively.

8. A method for regulating the phase output power of a low-voltage transformer, used in the system described in any one of claims 1-7, characterized in that, include: S110, Detect three-phase imbalance; S120. When the three-phase imbalance reaches the starting value, calculate the power that each phase of the transformer area needs to compensate. S130. Determine the regulating power sources that need to participate in the imbalance regulation of the distribution area, wherein the regulating power sources include distributed photovoltaic power and distributed small energy storage power sources in the distribution area. S140. Calculate the unbalanced adjustment power required to be output by each phase power regulation module, and determine the three-phase compensation reference current of the phase power regulation module. I a_ref , I b_ref , I c_ref ; S150, The converter hysteresis control of the phase power regulation module tracks the current reference value. I a_ref , I b_ref , I c_ref The actual compensation current of the converter is obtained from the phase power regulation module. I oa , I ob , I oc ; S160. Detect whether the change in the three-phase imbalance reaches the set offset value; S170. If the set offset value is not reached, repeat steps S120 to S160.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the low-voltage stage phase output power adjustment method as described in claim 8.

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