阅读说明：本技术 均流控制方法、装置和设备 (Current sharing control method, device and equipment ) 是由 李世伟 周文飞 于 2019-11-08 设计创作，主要内容包括：本发明涉及一种均流控制方法、装置和设备,通过获取所有逆变器的运行参数,对运行参数进行预处理,得到预处理后的控制参数,再根据控制参数中目标逆变器的目标控制参数以及上述的控制参数,计算下垂控制分量、补偿控制分量和误差控制分量,再将下垂控制分量、补偿控制分量和误差控制分量叠加到基准电压中,得到修正后的参考电压,根据参考电压,对目标逆变器进行均流控制,实现了进行下垂控制的同时对下垂控制分量带来的电压降进行补偿,同时误差控制分量的叠加减小单个逆变器运行参数和多个逆变器平均运行参数之间的误差,有效减小了均流控制中的电压降,避免了逆变器的输出外特性变软。(The invention relates to a current sharing control method, a device and equipment, which are characterized in that operation parameters of all inverters are obtained, the operation parameters are preprocessed to obtain preprocessed control parameters, droop control components, compensation control components and error control components are calculated according to target control parameters of target inverters in the control parameters and the control parameters, the droop control components, the compensation control components and the error control components are superposed into a reference voltage to obtain a corrected reference voltage, current sharing control is carried out on the target inverters according to the reference voltage, voltage drop caused by the droop control components is compensated while droop control is carried out, errors between the operation parameters of a single inverter and the average operation parameters of a plurality of inverters are reduced by superposition of the error control components, and the voltage drop in current sharing control is effectively reduced, the output external characteristic of the inverter is prevented from becoming soft.)

1. A method for current sharing control, comprising:

acquiring operation parameters of all inverters;

preprocessing the operation parameters to obtain control parameters;

obtaining a droop control component according to a target control parameter of a target inverter in the control parameters;

obtaining a compensation control component according to the average value of the control parameters;

obtaining an error control component according to the average value of the control parameters and the target control parameters;

superposing the droop control component, the compensation control component and the error control component to a reference voltage to obtain a reference voltage;

and performing current sharing control on the target inverter according to the reference voltage.

2. The current sharing control method of claim 1, wherein the operating parameters include an operating current value;

the preprocessing the operation parameters to obtain control parameters comprises the following steps:

and decomposing the operation current value in a preset dq coordinate system to obtain d-axis operation component current and q-axis operation component current, and taking the d-axis operation component current and the q-axis operation component current as the control parameters.

3. The current sharing control method of claim 2, wherein the target control parameters include a d-axis target component current and a q-axis target component current;

the droop control component comprises a d-axis droop control component and a q-axis droop control component;

the obtaining of the droop control component according to the target control parameter of the target inverter in the control parameters includes:

according to the d-axis target component current and the q-axis target component current, calculating a d-axis droop control component and a q-axis droop control component, wherein the calculation formula is as follows:

U_dref1＝m₁*I_d-m₂*I_q

U_qref1＝m₃*I_d+m₄*I_q

wherein m is₁、m₂、m₃And m₄Is a constant number, I_dFor the d-axis target component current, I_qFor said q-axis target component current, U_qref1For the q-axis droop control component, U_dref1Is the d-axis droop control component.

4. The current sharing control method according to claim 3, wherein the compensation control component comprises a q-axis compensation control component and a d-axis compensation control component;

obtaining a compensation control component according to the average value of the control parameter, including:

calculating the q-axis compensation control component and the d-axis compensation control component according to the first average value of the d-axis operation component current and the second average value of the q-axis operation component current, wherein the calculation formula is as follows:

U_dref2＝n₁*I_davg-n₂*I_qavg

U_qref2＝n₃*I_davg+n₄*I_qavg

wherein n is₁、n₂、n₃And n₄Is a constant number, I_davgIs said first mean value, I_qavgIs said second mean value, U_dref2Compensating the control component for said d-axis, U_qref2A control component is compensated for the q-axis.

5. The current sharing control method according to claim 4, wherein the error control component includes a q-axis error control component and a d-axis error control component;

obtaining an error control component according to the control parameter average value and the target control parameter, including:

calculating the q-axis error control component and the d-axis error control component according to the d-axis target component current, the q-axis target component current, the first average value and the second average value, wherein the calculation formula is as follows:

U_dref3＝p₁*(I_d-I_davg)-p₂*(I_q-I_qavg)

U_qref3＝p₃*(I_d-I_davg)+p₄*(I_q-I_qavg)

wherein p is₁、p₂、p₃And p₄Is constant, U_dref3For the d-axis error control component, U_qref3The q-axis error control component.

6. The current sharing control method according to claim 5, wherein the reference voltages include a d-axis reference voltage and a q-axis reference voltage;

the superimposing the droop control component, the compensation control component, and the error control component to a reference voltage to obtain a reference voltage includes:

decomposing the reference voltage in the dq coordinate system to obtain a d-axis reference voltage and a q-axis reference voltage;

reversely superimposing the d-axis droop control component and the d-axis error control component into the d-axis reference voltage, and forwardly superimposing the d-axis compensation control component into the d-axis reference voltage to obtain the d-axis reference voltage, wherein the calculation formula is as follows:

U_dref ^*＝U_dref0-U_dref1+U_dref2-U_dref3

wherein, U_dref ^*For the d-axis reference voltage, U_dref0Is the d-axis reference voltage;

reversely superimposing the q-axis droop control component and the q-axis error control component into the q-axis reference voltage, and positively superimposing the q-axis compensation control component into the q-axis reference voltage to obtain the q-axis reference voltage, wherein the calculation formula is as follows:

U_qref ^*＝U_qref0-U_qref1+U_qref2-U_qref3

wherein, U_qref ^*For said q-axis reference voltage, U_qef0Is the q-axis reference voltage.

7. The current sharing control method according to claim 1, wherein before adding the droop control component, the compensation control component, and the error control component to the reference voltage to obtain the reference voltage, the method further comprises:

acquiring the running state of the power grid where the target inverter is located;

if the running state of the power grid is a grid-connected state, taking the voltage of the power grid as the reference voltage;

and if the running state of the power grid is in an off-grid state, taking the alternating current voltage input by a user as the reference voltage.

8. A current share control device, comprising: the device comprises an acquisition module, a preprocessing module, a calculation module, a superposition module and a control module;

the acquisition module is used for acquiring the operating parameters of all inverters;

the preprocessing module is used for preprocessing the operation parameters to obtain control parameters;

the calculation module is used for obtaining a droop control component according to a target control parameter of a target inverter in the control parameters;

the calculation module is further used for obtaining a compensation control component according to the average value of the control parameter;

the calculation module is further used for obtaining an error control component according to the control parameter average value and the target control parameter;

the superposition module is used for superposing the droop control component, the compensation control component and the error control component to a reference voltage to obtain a reference voltage;

and the control module is used for carrying out current sharing control on the target inverter according to the reference voltage.

9. The current share control device of claim 8, wherein the operating parameters include operating current values;

the preprocessing module is specifically configured to decompose the operating current value in a preset dq coordinate system to obtain a d-axis operating component current and a q-axis operating component current, and use the d-axis operating component current and the q-axis operating component current as the control parameters.

10. The current-sharing control equipment is characterized by comprising a processor and a memory;

the processor is connected with the memory:

the processor is used for calling and executing the program stored in the memory;

the memory is used for storing the program, and the program is at least used for executing the current sharing control method of any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of current sharing control, in particular to a current sharing control method, device and equipment.

Background

The parallel operation of the inverters can realize high-capacity power supply and redundant power supply, and is one of the important directions of the current inversion technology development. The flexibility of the system can be improved by connecting a plurality of inverters in parallel, so that the volume and the weight of the power supply system are reduced, and the current stress of a main switching device can be greatly reduced, thereby fundamentally improving the power density and the reliability of the inverter power supply and reducing the cost. When the inverters are operated in parallel, the optimal state is that the output voltage amplitude of each inverter is equal, the frequency is equal, and the voltage difference is zero when the phases of the inverters are consistent.

However, in an actual inverter parallel system, due to differences in circuit parameters, frequent changes in load, and inherent control characteristics, instantaneous values of output voltages of the respective inverters cannot be completely equal, so that a certain voltage inverse difference is inevitably present, a circulating current is formed inside the system, and the circulating current has a certain destructive influence on power devices and output filters of the respective inverters. Therefore, in the inverter parallel operation system, the problem of voltage equalization control must be analyzed and solved. The PQ droop control method is a commonly used voltage current sharing control method at present, and although the PQ droop control method can realize current sharing among inverters connected in parallel, the PQ droop control method realizes current sharing at the cost of sacrificing the output voltage of the inverters. In a steady state, the larger the load, the larger the voltage drop, and the softer the external output characteristics of the inverter.

Therefore, when current sharing control is performed on the inverter parallel operation system, how to reduce the voltage drop and avoid the output external characteristic of the inverter from becoming soft is a problem to be solved urgently by those skilled in the art.

Disclosure of Invention

In view of this, an object of the present invention is to provide a current sharing control method, device and apparatus, so as to overcome the problem that the larger the load is, the larger the voltage drop is, and the output external characteristic of the inverter becomes soft when current sharing control is performed on an inverter parallel operation system.

In order to achieve the purpose, the invention adopts the following technical scheme:

a current sharing control method comprises the following steps:

acquiring operation parameters of all inverters;

preprocessing the operation parameters to obtain control parameters;

obtaining a droop control component according to a target control parameter of a target inverter in the control parameters;

obtaining a compensation control component according to the average value of the control parameters;

obtaining an error control component according to the average value of the control parameters and the target control parameters;

superposing the droop control component, the compensation control component and the error control component to a reference voltage to obtain a reference voltage;

and performing current sharing control on the target inverter according to the reference voltage.

Further, in the current sharing control method described above, the operating parameter includes an operating current value;

the preprocessing the operation parameters to obtain control parameters comprises the following steps:

and decomposing the operation current value in a preset dq coordinate system to obtain d-axis operation component current and q-axis operation component current, and taking the d-axis operation component current and the q-axis operation component current as the control parameters.

Further, in the current sharing control method described above, the target control parameter includes a d-axis target component current and a q-axis target component current;

the droop control component comprises a d-axis droop control component and a q-axis droop control component;

the obtaining of the droop control component according to the target control parameter of the target inverter in the control parameters includes:

according to the d-axis target component current and the q-axis target component current, calculating a d-axis droop control component and a q-axis droop control component, wherein the calculation formula is as follows:

U_dref1＝m₁*I_d-m₂*I_q

U_qref1＝m₃*I_d+m₄*I_q

wherein m is₁、m₂、m₃And m₄Is a constant number, I_dFor the d-axis target component current, I_qFor said q-axis target component current, U_qref1For the q-axis droop control component, U_dref1Is the d-axis droop control component.

Further, in the current sharing control method described above, the compensation control component includes a q-axis compensation control component and a d-axis compensation control component;

obtaining a compensation control component according to the average value of the control parameter, including:

calculating the q-axis compensation control component and the d-axis compensation control component according to the first average value of the d-axis operation component current and the second average value of the q-axis operation component current, wherein the calculation formula is as follows:

U_dref2＝n₁*I_davg-n₂*I_qavg

U_qref2＝n₃*I_davg+n₄*I_qavg

wherein n is₁、n₂、n₃And n₄Is a constant number, I_davgIs said first mean value, I_qavgIs said second mean value, U_dref2Compensating the control component for said d-axis, U_qref2A control component is compensated for the q-axis.

Further, in the current sharing control method described above, the error control component includes a q-axis error control component and a d-axis error control component;

obtaining an error control component according to the control parameter average value and the target control parameter, including:

calculating the q-axis error control component and the d-axis error control component according to the d-axis target component current, the q-axis target component current, the first average value and the second average value, wherein the calculation formula is as follows:

U_dref3＝p₁*(I_d-I_davg)-p₂*(I_q-I_qavg)

U_qref3＝p₃*(I_d-I_davg)+p₄*(I_q-I_qavg)

wherein p is₁、p₂、p₃And p₄Is constant, U_dref3For the d-axis error control component, U_qref3The q-axis error control component.

Further, in the current sharing control method, the reference voltages include a d-axis reference voltage and a q-axis reference voltage;

the superimposing the droop control component, the compensation control component, and the error control component to a reference voltage to obtain a reference voltage includes:

decomposing the reference voltage in the dq coordinate system to obtain a d-axis reference voltage and a q-axis reference voltage;

reversely superimposing the d-axis droop control component and the d-axis error control component into the d-axis reference voltage, and forwardly superimposing the d-axis compensation control component into the d-axis reference voltage to obtain the d-axis reference voltage, wherein the calculation formula is as follows:

U_dref ^*＝U_dref0-U_dref1+U_dref2-U_dref3

wherein, U_dref ^*For the d-axis reference voltage, U_dref0Is the d-axis reference voltage;

reversely superimposing the q-axis droop control component and the q-axis error control component into the q-axis reference voltage, and positively superimposing the q-axis compensation control component into the q-axis reference voltage to obtain the q-axis reference voltage, wherein the calculation formula is as follows:

U_qref ^*＝U_qref0-U_qref1+U_qref2-U_qref3

wherein, U_qref ^*For said q-axis reference voltage, U_qef0Is the q-axis reference voltage.

Further, before the step of superimposing the droop control component, the compensation control component, and the error control component on the reference voltage to obtain the reference voltage, the current sharing control method further includes:

acquiring the running state of the power grid where the target inverter is located;

if the running state of the power grid is a grid-connected state, taking the voltage of the power grid as the reference voltage;

and if the running state of the power grid is in an off-grid state, taking the alternating current voltage input by a user as the reference voltage.

The invention also provides a current sharing control device, comprising: the device comprises an acquisition module, a preprocessing module, a calculation module, a superposition module and a control module;

the acquisition module is used for acquiring the operating parameters of all inverters;

the preprocessing module is used for preprocessing the operation parameters to obtain control parameters;

the calculation module is used for obtaining a droop control component according to a target control parameter of a target inverter in the control parameters;

the calculation module is further used for obtaining a compensation control component according to the average value of the control parameter;

the calculation module is further used for obtaining an error control component according to the control parameter average value and the target control parameter;

the superposition module is used for superposing the droop control component, the compensation control component and the error control component to a reference voltage to obtain a reference voltage;

and the control module is used for carrying out current sharing control on the target inverter according to the reference voltage.

Further, in the current sharing control device described above, the operating parameter includes an operating current value;

the preprocessing module is specifically configured to decompose the operating current value in a preset dq coordinate system to obtain a d-axis operating component current and a q-axis operating component current, and use the d-axis operating component current and the q-axis operating component current as the control parameters.

The invention also provides a current-sharing control device, which comprises a processor and a memory;

the processor is connected with the memory:

the processor is used for calling and executing the program stored in the memory;

the memory is used for storing the program, and the program is at least used for executing the current sharing control method.

The current sharing control method, the device and the equipment of the invention can obtain the operation parameters of all inverters, preprocessing the operation parameters to obtain preprocessed control parameters, calculating droop control components, compensation control components and error control components according to the target control parameters of the target inverter in the control parameters and the control parameters, superposing the droop control components, the compensation control components and the error control components into a reference voltage to obtain a corrected reference voltage, and according to the reference voltage, the current sharing control is carried out on the target inverter, the droop control is realized, the voltage drop caused by the droop control component is compensated at the same time, meanwhile, the superposition of error control components reduces the error between the operating parameters of a single inverter and the average operating parameters of a plurality of inverters, effectively reduces the voltage drop in the current sharing control, and avoids the output external characteristics of the inverters from becoming soft.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a flow chart of a current sharing control method according to an embodiment of the present invention;

fig. 2 is a flowchart provided by a second embodiment of the current sharing control method of the present invention;

FIG. 3 is a block diagram of a current sharing control apparatus according to an embodiment of the present invention;

FIG. 4 is a block diagram of a current sharing control apparatus according to a second embodiment of the present invention;

fig. 5 is a structural diagram provided by the current share control apparatus of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

Fig. 1 is a flow chart of a current sharing control method according to an embodiment of the present invention. As shown in fig. 1, the current sharing control method of this embodiment may specifically include the following steps:

s100, obtaining operation parameters of all inverters;

in this embodiment, when a plurality of inverters are connected in parallel, the operation parameters of all the inverters connected in parallel can be obtained. In the present embodiment, it is preferable to obtain the operating current value of the inverter.

S101, preprocessing the operation parameters to obtain control parameters;

after the operation parameters of all the inverters connected in parallel are obtained, the operation parameters can be preprocessed to obtain preprocessed control parameters.

S102, obtaining a droop control component according to a target control parameter of a target inverter in the control parameters;

and acquiring target control parameters of target transformers to be controlled in all the parallel inverters, and calculating to obtain droop control components according to the target control parameters.

S103, obtaining a compensation control component according to the average value of the control parameter;

and calculating the average value of the running parameters of all the parallel inverters, and calculating to obtain the compensation control component according to the average value of the control parameters.

S104, obtaining an error control component according to the average value of the control parameters and the target control parameters;

and further calculating to obtain an error control component according to the average value of the control parameters and the target control parameters.

S105, superposing the droop control component, the compensation control component and the error control component to the reference voltage to obtain a reference voltage;

and superposing the droop control component, the compensation control component and the error control component in the reference voltage to obtain the reference voltage. Specifically, in the present embodiment, the droop control component and the error control component are reversely superimposed into the reference voltage, and the compensation control component is forwardly superimposed into the reference voltage.

And S106, performing current sharing control on the target inverter according to the reference voltage.

In this embodiment, current sharing control of the voltage outer loop and the current inner loop is performed on the target inverter according to the reference voltage obtained in the above step.

The current sharing control method, device and equipment of the embodiment can obtain the operation parameters of all inverters, preprocessing the operation parameters to obtain preprocessed control parameters, calculating droop control components, compensation control components and error control components according to the target control parameters of the target inverter in the control parameters and the control parameters, superposing the droop control components, the compensation control components and the error control components into a reference voltage to obtain a corrected reference voltage, and according to the reference voltage, the current sharing control is carried out on the target inverter, the droop control is realized, the voltage drop caused by the droop control component is compensated at the same time, meanwhile, the superposition of error control components reduces the error between the operating parameters of a single inverter and the average operating parameters of a plurality of inverters, effectively reduces the voltage drop in the current sharing control, and avoids the output external characteristics of the inverters from becoming soft.

Fig. 2 is a flowchart provided by a second embodiment of the current sharing control method of the present invention. As shown in fig. 2, the current sharing control method of this embodiment may specifically include the following steps:

s200, obtaining operation parameters of all inverters;

the execution process of this step is the same as the execution process of step S100 in the embodiment shown in fig. 1, and is not described herein again.

S201, decomposing the operation current value in the operation parameter in a preset dq coordinate system to obtain d-axis operation component current and q-axis operation component current, and taking the d-axis operation component current and the q-axis operation component current as control parameters;

in this embodiment, it is preferable to decompose the operating current value in the operating parameter in a preset dq coordinate system, the operating current value is decomposed into a d-axis operating component current and a q-axis operating component current, and the d-axis operating component current and the q-axis operating component current are used as the control parameters.

Correspondingly, the target operating current value of the target inverter is decomposed into a d-axis target component current and a q-axis target component current in the dq coordinate system.

S202, calculating a d-axis droop control component and a q-axis droop control component according to a d-axis target component current and a q-axis target component current which are obtained by decomposing a target running current value of a target inverter;

this step performs droop control on the inverter. Specifically, after obtaining the d-axis target component current and the q-axis target component current, calculating a d-axis droop control component and a q-axis droop control component according to the d-axis target component current and the q-axis target component current, wherein the calculation formula is as follows:

U_dref1＝m₁*I_d-m₂*I_q

U_qref1＝m₃*I_d+m₄*I_q

wherein m is₁、m₂、m₃And m₄As a constant, m is preferably set in this embodiment₁、m₂、m₃And m₄Setting a constant of 0 to 1, wherein the actual value can be set according to the actual requirement, and if the stability is to be improved, setting m₁、m₂、m₃And m₄Close to 1, if the running speed is to be increased, m can be set₁、m₂、m₃And m₄Close to 0; i is_dIs the d-axis target component current; i is_qIs the q-axis target component current; u shape_qref1Is a q-axis droop control component; u shape_dref1Is the d-axis droop control component.

In this embodiment, the d-axis target component current and the q-axis target component current are obtained in the dq coordinate system as the operating current values, and the d-axis target component current and the q-axis target component current can be used for control.

S203, calculating a q-axis compensation control component and a d-axis compensation control component according to the first average value of the d-axis operation component current and the second average value of the q-axis operation component current;

this step performs compensation control on the inverter. Calculating a q-axis compensation control component and a d-axis compensation control component according to a first average value of d-axis operation component current and a second average value of q-axis operation component current obtained by decomposing the operation current value, wherein the calculation formula is as follows:

U_dref2＝n₁*I_davg-n₂*I_qavg

U_qref2＝n₃*I_davg+n₄*I_qavg

wherein n is₁、n₂、n₃And n₄As a constant, this embodiment preferably will n₁、n₂、n₃And n₄Set to a constant of 0 to 1, m being as defined above₁、m₂、m₃And m₄Is correspondingly adjusted by n₁、n₂、n₃And n₄To achieve relatively stable and fast control; i is_davgIs a first average value; i is_qavgIs a second average value; u shape_dref2Compensating the control component for the d-axis, U_qref2The control component is compensated for the q-axis.

The compensation control of the embodiment corresponds to droop control of an operating current value, the compensation control component is obtained by droop control of a first average value and a second average value, and average current of a plurality of inverters is added into voltage outer loop control by the average current droop control, so that the compensation effect is ensured, and better current sharing control is facilitated.

S204, calculating a q-axis error control component and a d-axis error control component according to the d-axis target component current, the q-axis target component current, the first average value and the second average value;

this step performs error control on the inverter. Specifically, the q-axis error control component and the d-axis error control component may be calculated according to the obtained d-axis target component current, q-axis target component current, first average value, and second average value, where the calculation formula is:

U_dref3＝p₁*(I_d-I_davg)-p₂*(I_q-I_qavg)

U_qref3＝p₃*(I_d-I_davg)+p₄*(I_q-I_qavg)

wherein p is₁、p₂、p₃And p₄As a constant, this embodiment preferably will be given p₁、p₂、p₃And p₄Setting a constant from 0 to 1, wherein the actual value can be set according to the actual requirement, and if the running speed is to be increased, setting p₁、p₂、p₃And p₄Close to 1, p may be set if stability is to be improved₁、p₂、p₃And p₄Close to 0; i is_dIs the d-axis target component current; i is_qIs the q-axis target component current; u shape_dref3As d-axis error control component, U_qref3Is the q-axis error control component.

The error control in the invention adopts the error between the target inverter current and the average current of a plurality of inverters connected in parallel as the control object, and the error between the single inverter current and the average current of the plurality of inverters is smaller and smaller along with the control, and finally tends to zero, so that the final output tends to be stable.

S205, acquiring the running state of the power grid where the target inverter is located;

the operating states of the power grid where the inverter is located are different, and the reference voltages are also different, so the present embodiment preferably obtains the operating state of the power grid where the target inverter is located.

S206, judging whether the running state of the power grid is a grid-connected state, if so, executing S207, and if not, executing S208;

after the operation state of the power grid where the target inverter is located is obtained, whether the operation state of the power grid is a grid-connected state or not can be judged, if the operation state of the power grid is the grid-connected state, S207 can be executed, and if the operation state of the power grid is not the grid-connected state, it indicates that the operation state of the power grid is an off-grid state, and S208 can be executed.

S207, taking the power grid voltage as a reference voltage;

if the operation state of the power grid is a grid-connected state, the voltage of the power grid can be used as the reference voltage.

S208, taking the alternating-current voltage input by the user as a reference voltage;

if the operation state of the power grid is the off-grid state, the alternating voltage input by the user can be used as the reference voltage.

Specifically, the present embodiment does not limit the execution order between S200-S204 and S205-S208.

S209, decomposing the reference voltage in a dq coordinate system to obtain a d-axis reference voltage and a q-axis reference voltage;

and decomposing the reference voltage obtained in the step in a dq coordinate system, wherein the reference voltage can be decomposed into a d-axis reference voltage and a q-axis reference voltage.

S210, reversely superposing a d-axis droop control component and a d-axis error control component to a d-axis reference voltage, and forwardly superposing a d-axis compensation control component to the d-axis reference voltage to obtain a d-axis reference voltage;

the d-axis reference voltage is obtained by superimposing the d-axis droop control component, the d-axis error control component and the d-axis reference voltage in the d-axis reference voltage, specifically, the d-axis droop control component and the d-axis error control component may be reversely superimposed in the d-axis reference voltage, and the d-axis compensation control component may be forwardly superimposed in the d-axis reference voltage.

The calculation formula is as follows:

U_dref ^*＝U_dref0-U_dref1+U_dref2-U_dref3

wherein, U_dref ^*Is d-axis reference voltage, U_dref0Is the d-axis reference voltage.

S211, reversely superposing a q-axis droop control component and a q-axis error control component to q-axis reference voltage, and forwardly superposing a q-axis compensation control component to the q-axis reference voltage to obtain q-axis reference voltage;

the q-axis reference voltage is obtained by superimposing a q-axis droop control component, a q-axis error control component and a q-axis reference voltage in the q-axis reference voltage, and specifically, the q-axis droop control component and the q-axis error control component may be reversely superimposed in the q-axis reference voltage, and the q-axis compensation control component may be forwardly superimposed in the q-axis reference voltage.

The calculation formula is as follows:

U_qref ^*＝U_qref0-U_qref1+U_qref2-U_qref3

wherein, U_qref ^*For q-axis reference voltage, U_qef0Is the q-axis reference voltage.

And S212, performing current sharing control on the target inverter according to the reference voltage.

The current sharing control is carried out on the target inverter according to the q-axis reference voltage and the d-axis reference voltage respectively, so that the decoupling of the d-axis component and the q-axis component is realized, and the improvement of the precision of voltage outer loop control and current inner loop control is facilitated.

The current sharing control method of the embodiment decomposes the operation current value in a preset dq coordinate system after obtaining the operation current value of the inverter to obtain d-axis operation component current and q-axis operation component current, obtains d-axis droop control component, d-axis compensation control component and d-axis error control component according to the d-axis operation component current and the d-axis target component current, and then superposes the d-axis droop control component, the d-axis compensation control component and the d-axis error control component on the reference voltage obtained according to the power grid operation state to obtain final d-axis reference voltage, similarly obtains q-axis reference voltage, performs current sharing control on the target inverter according to the d-axis reference voltage and the q-axis reference voltage, compensates the voltage drop caused by the droop control component while performing droop control, and simultaneously superposes the error control component to reduce the error between the operation parameter of a single inverter and the average operation parameters of a plurality of inverters, and effectively reduces the, the output external characteristic of the inverter is prevented from becoming soft.

Fig. 3 is a structural diagram of a current sharing control apparatus according to an embodiment of the present invention. In order to be more comprehensive, the present application further provides a current sharing control apparatus corresponding to the current sharing control method provided in the embodiment of the present invention.

Referring to fig. 3, the current sharing control apparatus of the present embodiment may include an obtaining module 11, a preprocessing module 12, a calculating module 13, a superimposing module 14, and a control module 15;

the acquisition module 11 is used for acquiring the operation parameters of all inverters;

the preprocessing module 12 is used for preprocessing the operation parameters to obtain control parameters;

the calculation module 13 is configured to obtain a droop control component according to a target control parameter of the target inverter in the control parameters;

the calculation module 13 is further configured to obtain a compensation control component according to the average value of the control parameter;

the calculation module 13 is further configured to obtain an error control component according to the average value of the control parameter and the target control parameter;

the superposition module 14 is configured to superimpose the droop control component, the compensation control component, and the error control component onto the reference voltage to obtain a reference voltage;

and the control module 15 is configured to perform current sharing control on the target inverter according to the reference voltage.

In the current sharing control method of this embodiment, the obtaining module 11 obtains the operation parameters of all inverters, the preprocessing module 12 preprocesses the operation parameters to obtain the preprocessed control parameters, the calculating module 13 calculates the droop control component, the compensation control component and the error control component according to the target control parameters of the target inverter in the control parameters and the control parameters, the superimposing module 14 superimposes the droop control component, the compensation control component and the error control component on the reference voltage to obtain the corrected reference voltage, the control module 15 performs current sharing control on the target inverter according to the reference voltage, so as to compensate the voltage drop caused by the droop control component while performing droop control, and the superimposing of the error control component reduces the error between the operation parameters of a single inverter and the average operation parameters of a plurality of inverters, the voltage drop in the current sharing control is effectively reduced, and the output external characteristic of the inverter is prevented from becoming soft.

With regard to the apparatus in the above-described embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment related to the method, and will not be elaborated here.

Fig. 4 is a structural diagram of a current sharing control apparatus according to a second embodiment of the present invention. The current sharing control apparatus of this embodiment is further described in more detail based on the embodiment of fig. 3.

The operating parameters of the present embodiment include an operating current value;

the preprocessing module 12 is specifically configured to decompose the operation current value in a preset dq coordinate system to obtain a d-axis operation component current and a q-axis operation component current, and use the d-axis operation component current and the q-axis operation component current as control parameters.

Further, in the target control parameters of the present embodiment, the d-axis target component current and the q-axis target component current, the droop control component includes a d-axis droop control component and a q-axis droop control component;

the calculating module 13 is specifically configured to calculate a d-axis droop control component and a q-axis droop control component according to the d-axis target component current and the q-axis target component current, where the calculation formula is as follows:

U_dref1＝m₁*I_d-m₂*I_q

U_qref1＝m₃*I_d+m₄*I_q

wherein m is₁、m₂、m₃And m₄Is a constant number, I_dIs d-axis target component current, I_qFor q-axis target component current, U_qref1For q-axis droop control component, U_dref1Is the d-axis droop control component.

Further, the compensation control component of the present embodiment includes a q-axis compensation control component and a d-axis compensation control component;

the calculating module 13 is further specifically configured to calculate a q-axis compensation control component and a d-axis compensation control component according to a first average value of the d-axis operation component current and a second average value of the q-axis operation component current, where the calculation formula is as follows:

U_dref2＝n₁*I_davg-n₂*I_qavg

U_qref2＝n₃*I_davg+n₄*I_qavg

wherein n is₁、n₂、n₃And n₄Is a constant number, I_davgIs a first average value, I_qavgIs a second average value, U_dref2Compensating the control component for the d-axis, U_qref2The control component is compensated for the q-axis.

Further, the error control component of the present embodiment includes a q-axis error control component and a d-axis error control component;

the calculating module 13 is further specifically configured to calculate a q-axis error control component and a d-axis error control component according to the d-axis target component current, the q-axis target component current, the first average value, and the second average value, where the calculation formula is as follows:

U_dref3＝p₁*(I_d-I_davg)-p₂*(I_q-I_qavg)

U_qref3＝p₃*(I_d-I_davg)+p₄*(I_q-I_qavg)

wherein p is₁、p₂、p₃And p₄Is constant, U_dref3As d-axis error control component, U_qref3Is the q-axis error control component.

Further, the reference voltage of the present embodiment includes a d-axis reference voltage and a q-axis reference voltage;

the superposition module 14 is specifically configured to decompose the reference voltage in a dq coordinate system to obtain a d-axis reference voltage and a q-axis reference voltage;

reversely superposing the d-axis droop control component and the d-axis error control component to the d-axis reference voltage, and forwardly superposing the d-axis compensation control component to the d-axis reference voltage to obtain a d-axis reference voltage, wherein the calculation formula is as follows:

U_dref ^*＝U_dref0-U_dref1+U_dref2-U_dref3

wherein, U_dref ^*Is d-axis reference voltage, U_dref0Is a d-axis reference voltage;

reversely superposing the q-axis droop control component and the q-axis error control component to the q-axis reference voltage, and positively superposing the q-axis compensation control component to the q-axis reference voltage to obtain the q-axis reference voltage, wherein the calculation formula is as follows:

U_qref ^*＝U_qref0-U_qref1+U_qref2-U_qref3

wherein, U_qref ^*For q-axis reference voltage, U_qef0Is the q-axis reference voltage.

Further, the current sharing control apparatus of this embodiment further includes a determining module 16;

the obtaining module 11 is further configured to obtain an operation state of a power grid where the target inverter is located;

the determining module 16 is configured to, if the operation state of the power grid is a grid-connected state, use the voltage of the power grid as a reference voltage; and if the running state of the power grid is in an off-grid state, taking the alternating voltage input by the user as the reference voltage.

In the current-sharing control device of this embodiment, after the obtaining module 11 obtains the operating current value of the inverter, the preprocessing module 12 decomposes the operating current value in a preset dq coordinate system to obtain a d-axis operating component current and a q-axis operating component current, the calculating module 13 obtains a d-axis droop control component, a d-axis compensation control component and a d-axis error control component according to the d-axis operating component current and the d-axis target component current, the superimposing module 14 superimposes the above components on the reference voltage obtained by the determining module 16 according to the operating state of the power grid to obtain a final d-axis reference voltage, and similarly obtains a q-axis reference voltage, the controlling module 15 performs current-sharing control on the target inverter according to the d-axis reference voltage and the q-axis reference voltage, so as to compensate the voltage drop caused by the droop control component while performing the droop control, and simultaneously the superimposing of the error control component reduces the error between the operating parameter of a single inverter and the average operating parameters, the voltage drop in the current sharing control is effectively reduced, and the output external characteristic of the inverter is prevented from becoming soft.

With regard to the apparatus in the above-described embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment related to the method, and will not be elaborated here.

Fig. 5 is a structural diagram provided by the current share control apparatus of the present invention. In order to be more comprehensive, the present application also provides a current sharing control device corresponding to the current sharing control method provided in the embodiment of the present invention.

Referring to fig. 5, the current sharing control apparatus of the present embodiment includes a processor 21 and a memory 22; the processor 21 is connected to the memory 22: the processor 21 is configured to call and execute a program stored in the memory 22; the memory 22 is used for storing a program, and the program is used for executing the current sharing control method of the above embodiment. The current-sharing control equipment of the embodiment compensates voltage drop caused by droop control components while droop control is performed, errors between single inverter operation parameters and average operation parameters of a plurality of inverters are reduced by superposition of error control components, voltage drop in current-sharing control is effectively reduced, and output external characteristics of the inverters are prevented from becoming soft.

It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.

It should be noted that the terms "first," "second," and the like in the description of the present invention are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present invention, the meaning of "a plurality" means at least two unless otherwise specified.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.