CN111641203B

CN111641203B - DC voltage source system, control method, and storage medium

Info

Publication number: CN111641203B
Application number: CN202010764978.0A
Authority: CN
Inventors: 杨耀; 杨惠坤; 朱建国
Original assignee: Shenzhen Winline Technology Co Ltd
Current assignee: Shenzhen Winline Technology Co Ltd
Priority date: 2020-08-03
Filing date: 2020-08-03
Publication date: 2021-08-20
Anticipated expiration: 2040-08-03
Also published as: CN111641203A

Abstract

The application discloses a direct current voltage source system, a control method and a storage medium. A dc voltage source system, comprising: a main control module; and the plurality of direct current voltage sources are in communication connection with the main control module. Wherein the plurality of DC voltage sources are arranged in parallel and the DC voltage sources comprise droop control modules for droop control. The droop control module is configured to perform droop control on each direct-current voltage source according to the first set voltage value received from the main control module, the system output voltage value output by the direct-current voltage source system, and the voltage source output current value output by each direct-current voltage source. Wherein the master control module is further configured to: receiving an input second set voltage value, wherein the second set voltage value is used for indicating a voltage to be output by the direct current voltage source system; and compensating the second set voltage value according to the difference value between the second set voltage value and the system output voltage value, and determining the first set voltage value.

Description

DC voltage source system, control method, and storage medium

Technical Field

The present invention relates to a dc voltage source parallel control technology, and in particular, to a dc voltage source system, a control method, and a storage medium.

Background

Along with the expansion of direct current electric load, the power capacity requirement of the direct current voltage source is higher and higher, but the power capacity of a single direct current voltage source is limited by the size and the cost and cannot meet the larger and larger load requirement, and the parallel operation between the direct current voltage sources can adjust the parallel operation quantity as required, so that the whole direct current voltage source whole system can meet the load requirement.

In the parallel operation of the current direct current voltage sources, better transient response and steady-state stability can be obtained based on droop control. According to the parallel operation method based on droop control, parallel operation communication lines do not need to be arranged among direct-current voltage sources, all the power sources are in an equal relation, and a master power source and a slave power source do not exist. Each direct current voltage source can be put into a common direct current bus at any time to share load or be cut out at any time, and other direct current voltage sources do not need to be started or stopped to cooperate in the whole process. On the other hand, because errors exist in respective sampling circuits between the direct current voltage sources, after the sampling errors are introduced into the control loop, imbalance exists in output power between the direct current voltage sources, and a parallel operation communication line is generally additionally arranged between the direct current voltage sources based on droop control, so that the input power and the output power of each direct current voltage source are kept balanced.

However, the droop control is a poor control method, that is, the actual output voltage deviates from the set value, and the larger the input/output power is, the larger the deviation between the actual voltage and the set voltage is. Resulting in a significant reduction of the control accuracy of the dc voltage source system. On the other hand, the voltage deviation is also influenced by the droop coefficient, the larger the droop coefficient is, the better the current equalizing effect among the direct current voltage sources is, but the larger the voltage deviation is; the smaller the droop coefficient, the smaller the voltage deviation, but the poorer the current sharing effect among the DC voltage sources. Resulting in a further reduction in the control accuracy of the dc voltage source system.

In view of the above technical problem in the prior art that droop control causes a reduction in control accuracy of parallel operation of dc voltage sources, no effective solution has been proposed at present.

Disclosure of Invention

The present disclosure provides a dc voltage source system, a control method, and a storage medium, to at least solve a technical problem in the prior art that droop control causes a reduction in control accuracy of parallel operation of dc voltage sources.

According to an aspect of the present application, there is provided a direct current voltage source system including: a main control module; and the plurality of direct current voltage sources are in communication connection with the main control module. Wherein the plurality of DC voltage sources are arranged in parallel and the DC voltage sources comprise droop control modules for droop control. The droop control module is configured to perform droop control on each direct-current voltage source according to the first set voltage value received from the main control module, the system output voltage value output by the direct-current voltage source system, and the voltage source output current value output by each direct-current voltage source. Wherein the master control module is further configured to: receiving an input second set voltage value, wherein the second set voltage value is used for indicating a voltage to be output by the direct current voltage source system; and compensating the second set voltage value according to the difference value between the second set voltage value and the system output voltage value, and determining the first set voltage value.

According to another aspect of the present application, a method for controlling a plurality of dc voltage sources connected in parallel is provided, which is applied to a main control module for controlling the plurality of dc voltage sources. The droop control module is configured to perform droop control on the respective direct current voltage source according to a first set voltage value received from the main control module, an output voltage value of the direct current voltage source, and a voltage source output current value output by the respective direct current voltage source. The method comprises the following steps: receiving an input second set voltage value, wherein the second set voltage value is used for indicating the voltage to be output by the direct-current voltage source; and compensating the second set voltage value according to the difference value between the second set voltage value and the output voltage value of the direct current voltage source, and determining the first set voltage value.

According to another aspect of the application, a storage medium is provided, the storage medium comprising a stored program, wherein the method described above is performed by a processor when the program is run.

According to the technical scheme of the application, the main control module receives a second set voltage value input by a worker, and the second set voltage value is used for indicating the voltage to be output by the direct current voltage source system. And the main control module compensates the second set voltage value according to the difference between the second set voltage value and the system output voltage value, so as to determine the first set voltage value. In this way, the compensated first set voltage value is transmitted to the respective dc voltage sources, so that the deviation between the actual output voltage and the first set value can be compensated, and the output voltage of the dc voltage source system can be equal to the second set voltage value input by the operator. Therefore, the technical problem that the droop control in the prior art causes the control precision of the parallel operation of the direct-current voltage sources to be reduced is solved.

The above and other objects, advantages and features of the present application will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the present application will be described in detail hereinafter by way of illustration and not limitation with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a block schematic diagram of a DC voltage source system according to one embodiment of the present application;

FIG. 2 is a detailed schematic diagram of a DC voltage source system according to one embodiment of the present application;

fig. 3 is a flowchart illustrating operations performed by a master control module of the dc voltage source system according to an embodiment of the present application; and

fig. 4 is a schematic flow chart of a method for controlling a plurality of dc voltage sources connected in parallel according to a second aspect of an embodiment of the present application.

Detailed Description

It should be noted that, in the present disclosure, the embodiments and features of the embodiments may be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

In order to make the technical solutions of the present disclosure better understood by those skilled in the art, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only some embodiments of the present disclosure, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

It should be noted that the terms "first," "second," and the like in the description and claims of the present disclosure and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances for describing the embodiments of the disclosure herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

Referring to fig. 1 and 2, according to a first aspect of the present embodiment, there is provided a direct current voltage source system including: a main control module 100; and a plurality of dc voltage sources 210,220, 2N0 communicatively coupled to master control module 100. Wherein a plurality of dc voltage sources 210,220, 2N0 are arranged in parallel, and the dc voltage sources 210,220, 2N0 comprise

droop control modules

211, 221, 2N1 for droop control. The

droop control modules

211, 221, and 211N and 2N1 are configured to perform droop control on the respective dc voltage sources 210,220, and 2N0 according to the first set voltage value Vs received from the main control module 100, the system output voltage value Vout output by the dc voltage source system, and the voltage source output current values Iout1, Iout2, and the system output current values Iout and Iout output by the respective dc voltage sources 210,220, and 2N 0. As shown in fig. 3, the main control module 100 is further configured to perform the following operations:

s302: receiving an input second set voltage value Vset, wherein the second set voltage value Vset is used for indicating a voltage to be output by the direct-current voltage source system; and

s304: the first set voltage value Vs is determined by compensating the second set voltage value Vset according to a difference between the second set voltage value Vset and the difference between the system output voltage values Vout.

Specifically, as described in the background, droop control is a poor control method in the parallel operation of current dc voltage sources. For example, as shown in fig. 2, for each dc voltage source 210,220, 2N0, there is a deviation between the actual output voltage Vout and the voltage setpoint Vs input to the dc voltage source 210,220, 2N 0. For example, for DC voltage source 210, the deviation is Vdr1-Vav 1; for DC voltage source 220, the deviation is Vdr2-Vav 2; and for a dc voltage source 2N0 the deviation is VdrN-VavN.

Therefore, since the actual output voltage Vout deviates from the set value Vs for each of the dc voltage sources 210,220, 2N0, the larger the input/output power, the larger the deviation between the actual voltage and the set voltage. Resulting in a significant reduction of the control accuracy of the dc voltage source system.

In view of this, referring to fig. 1 and 2, according to the present embodiment, the main control module 100 receives a second set voltage value Vset input by the operator, where the second set voltage value Vset is used for indicating a voltage to be output by the dc voltage source system. Also, the main control module 100 compensates the second set voltage value Vset according to a difference between the second set voltage value Vset and the system output voltage value Vout, thereby determining the first set voltage value Vs.

In this way, the compensated first set voltage value Vs is sent to the respective dc voltage sources 210,220, 2N0, so that the deviation between the actual output voltage Vout and the first set value Vs can be compensated, so that the output voltage Vout of the dc voltage source system can be equal to the second set voltage value Vset input by the operator. Therefore, the technical problem that the droop control in the prior art causes the control precision of the parallel operation of the direct-current voltage sources to be reduced is solved.

Further, as an example, the main control module 100 may obtain a system output voltage value Vout from a dc bus 300 measurement of the dc voltage source system, for example, and the

droop control modules

211, 221, a.

Alternatively, the operation of determining the first set voltage value Vs by compensating the second set voltage value Vset according to a difference between the second set voltage value Vset and the difference between the system output voltage values Vout includes: performing proportional integral operation according to a difference value between the second set voltage value Vset and the system output voltage value Vout, and determining a first control voltage value Vc as an operation result; and summing the second set voltage value Vset and the first control voltage value Vc to determine a first set voltage value Vs.

Specifically referring to fig. 2, the main control module 100 first calculates a difference between the second set voltage value Vset and the system output voltage value Vout, and then inputs the difference to a proportional-integral controller (i.e., PI controller) to calculate a first control voltage value Vc, i.e., a voltage compensation value Vc. Then, the main control module 100 superimposes the second setting voltage value Vset on the first control voltage value Vc, thereby obtaining a first setting voltage value Vs sent to each of the dc voltage sources 210, 220.

Therefore, the main control module 100 utilizes a proportional link in PI control to generate a control effect on the deviation between the second set voltage value Vset and the system output voltage value Vout, so that the response speed of the system control deviation is increased; and the main control module 100 utilizes an integral link in the PI control to improve the zero-difference degree of the system. In this way, the steady state performance of the control system is thus improved.

Optionally, the main control module 100 is further configured to: determining an average power value Pav of the plurality of dc voltage sources 210,220, ·,2N 0; and sending the average power value Pav to the plurality of direct current voltage sources 210, 220. And the

droop control modules

211, 221,. and 2N1 are further configured to perform droop control on the respective dc voltage sources 210,220,. and 2N0 according to the first set voltage value Vs and the average power value Pav received from the main control module 100, the system output voltage value Vout, and the respective voltage source output current values Iout1, Iout2,. and IoutN.

And, further, the

droop control modules

211, 221, the..... and 2N1 perform droop control operations on the respective dc voltage sources 210,220, the... and 2N0 according to the first set voltage value Vs and the average power value Pav received from the main control module 100, the system output voltage value Vout, and the respective voltage source output current values Iout1, Iout2, the... and IoutN, including:

determining respective voltage source output powers Pout1, Pout2, and Pout of Pout2 and the respective voltage source output current values Iout1, Iout 2; performing proportional integral operation according to the average power value Pav and the respective voltage source output powers Pout1, Pout2, the.... and PoutN to determine respective second control voltage values Vav1, Vav2, the.... and VavN; summing the first set voltage value and the respective second control voltage values Vav1, Vav2, the. Determining respective third control voltage values Vdr1, Vdr2, VdrN according to the respective voltage source output powers Pout1, Pout2, a...... times, PoutN and the respective droop coefficients K1, K2, a.... times, KN; and calculating a difference between the respective first reference voltage values Vr1, Vr2, ·.. and VrN and the respective third control voltage values Vdr1, Vdr2,. and · VrefN, determining respective second reference voltage values Vref1, Vref2,. and.. and VrefN.

Specifically, referring to fig. 1 and 2, the

droop control modules

211, 221, and 2N1 of the respective dc voltage sources respectively perform droop control on the respective dc voltage sources 210,220, and 2N0 according to the first set voltage value Vs and the average power value Pav received from the main control module 100, the system output voltage value Vout, and the respective voltage source output current values Iout1, Iout2, and the.

Taking the droop control module 211 of the dc voltage source 210 as an example, referring to fig. 2, the droop control module 211 multiplies the system output voltage Vout by the voltage source output current Iout1 of the dc voltage source 210 to determine the voltage source output power Pout1 of the dc voltage source 210. Then, the droop control module 211 inputs the difference between the average power value Pav received from the main control module 100 and the voltage source output power Pout1 of the dc voltage source 210 to the PI controller for proportional-integral operation, and the second control voltage value Vav1 of the dc voltage source 210. Then, the droop control module 211 sums the first setting voltage value Vs and the second control voltage value Vav1 to determine a first reference voltage value Vr 1. The droop control module 211 then determines the third control voltage value Vdr1 of the dc voltage source 210 by multiplying the voltage source output power Pout1 of the dc voltage source 210 by the droop coefficient K1 of the dc voltage source 210. Then, the droop control module 210 calculates a difference between the first reference voltage value Vr1 and the third control voltage value Vdr1, and determines a second reference voltage value Vref1 of the dc voltage source 210.

Referring to FIG. 2, the droop control modules 221-2N 1 of the DC voltage sources 220-2N 0 respectively calculate the second reference voltage values Vref 2-Vrefn of the DC voltage sources in the manner described above.

Thus, taking the dc voltage source 210 as an example for analysis, the control loop employs droop control plus voltage current loop control. When the voltage source output power is Pout1, the voltage set-point (i.e., the second reference voltage value) Vref1= Vr1-Vdr1 of the voltage-current PI control module 212, where Vdr1= Pout1 × K1 is the introduced voltage deviation (i.e., the third control voltage), and the larger the output power, the larger the voltage deviation Vdr1, the smaller the second reference voltage value Vref1 of the control loop, and the output power is reversely adjusted by introducing the voltage deviation negative feedback. Therefore, when the output power Pout1 of the DC voltage source 210 is greater than the output power PoutN of the other DC voltage sources, the voltage deviation (i.e., the third control voltage) Vdr1 of the DC voltage source 201 is greater than the voltage deviation (i.e., the third control voltage) Vdr2 VdrN of the other DC voltage sources 220-2N 0. Therefore, the second reference voltage value Verf1 of the DC voltage source 210 is adjusted to be smaller than the second reference voltage values Vref 2-VrefN of other DC voltage sources, so that the output power Pout1 of the DC voltage source 210 is reduced. When the output power Pout1 of the DC voltage source 210 is smaller than the output powers Pout 2-PoutN of other DC voltage sources, the voltage deviation Vdr1 (i.e. the third control voltage) of the DC voltage source 210 is smaller than the voltage deviations Vdr 2-VdrN of the other DC voltage sources 220-2N 0 (i.e. the third control voltage), the second reference voltage value Verf1 of the DC voltage source 210 is adjusted to be larger than the second reference voltage values Verf 2-Vrefn of other voltage sources, so that the output power Pout1 of the DC voltage source 210 is increased. Finally, the output power of the dc voltage source 210 under the steady state is equal to the output power of other dc voltage sources, Pout1= Pout2= … = PoutN.

In addition, in practical application, the actual output power of each dc voltage source is not equal due to the error of the sampling circuit. Therefore, in the embodiment, the main control module 100 is used to calculate the average power Pav = (Pout1+ Pout2+ … + PoutN)/N of each dc voltage source, and send the average power Pav to all the dc voltage sources 210 to 2N0 through the communication bus. Taking the dc voltage source 210 as an example for analysis: the difference between the average power Pav and the actual output power Pout1 is processed by the PI controller to obtain a second control voltage Vav 1. Vs is the first voltage set point issued by the master control module 100 to all DC voltage sources 210-2N 0, and where Vr1= Vs + Vav 1. Therefore, when Pout1> Pav, Vav1<0, Vr1< Vs, the regulated output voltage decreases, so that the output Pout1 decreases. When Pout1< Pav, Vav1>0, Vr1> Vs, the regulated output voltage rises, causing the output power Pout1 to increase. Eventually, the output power Pout1 is equal to the average power Pav in the steady state.

In addition, the other direct current voltage sources 210-2N 0 also execute the control method, and finally, the output power of all the direct current voltage sources under the steady state is equal to Pout1= Pout2= … = PoutN.

Optionally, the droop coefficients K1 KN of the droop control modules 211 to 2N1 satisfy the following conditions: the droop coefficients K1-KN of the droop control modules 211-2N 1 are equal to the products of the voltage source rated powers Pn 1-PnN of the corresponding direct-current voltage sources 210-2N 0; the output power of the DC voltage source system is the weighted sum of the voltage source output powers Pout1 PoutN of the DC voltage sources 210-2N 0, and the weighted value corresponding to each DC voltage source 210-2N 0 is the droop coefficient K1-KN.

Specifically, the rated powers of the DC voltage sources 210-2N 0 are Pn 1-PnN respectively, and droop control is adopted to realize parallel operation of the DC voltage sources. The droop coefficients K1-KN and the rated powers Pn 1-PnN of the direct current voltage sources 210-2N 0 satisfy the following relations: pn1 × K1= Pn2 × K2 … PnN × KN. And the output power Pout1 and Pout2 … PoutN of each DC power supply 210-2N 0 share the total power Psum according to the respective droop coefficients, and the relationship is: psum = Pout1 × K1+ Pout2 × K2+ … + PoutN × KN.

The droop coefficients K1-KN can be determined according to the following formula:

k = Δ V/Δ Power. I.e. the increase in the output power of the dc supply multiplied by the droop factor equals the increase in the dc supply voltage. So that the droop coefficient is equal to the variation of the output voltage of the dc power supply divided by the variation of the output power.

In particular, when the dc voltage sources have the same rated power, that is, Pn1= Pn2= … = PnN, the droop coefficients are also equal, and the output power is also equal to Pout1= Pout2= … = PoutN. For simplicity of analysis, the dc voltage source modules are illustrated as being of the same power rating. The output power Pout of any dc voltage source is proportional to the output voltage Vout, i.e. the output power of any dc voltage source is larger when the output voltage is larger without changing the load.

Optionally, the DC voltage sources 210-2N 0 further include: the voltage and current PI control modules 212-2N 2, the PWM modules 213-2N 3, and the power modules 214-2N 4. The voltage and current PI control modules 212-2N 2 are connected with the droop control modules 211-2N 1 of the respective DC voltage sources 210-2N 0, and configured to perform voltage PI control and current PI control according to second reference voltage values Vref 1-Vrefn output by the respective droop control modules 211-2N 1, so as to generate modulation parameters for controlling the respective PWM modules 213-2N 3; the PWM modules 213 to 2N3 are connected to the respective voltage and current PI control modules 212 to 2N2, and configured to generate PWM signals for controlling the respective power modules 214 to 2N4 according to modulation parameters output by the respective voltage and current PI control modules 212 to 2N 2; and the power modules 214 to 2N4 are connected to the respective PWM modules 213 to 2N3, and configured to generate respective output voltages according to the PWM signals generated by the respective PWM modules 213 to 2N 3.

Specifically, referring to fig. 1 and 2, a dc voltage source 210 is taken as an example. The voltage and current PI control module 212 is configured to perform PI control on a difference input voltage PI loop between the second reference voltage Vref1 and the system output voltage Vout, and perform PI control on a difference input current PI loop between an output result of the voltage PI loop and the voltage source output current value Iout1, so as to obtain a modulation parameter for modulating the PWM module 213.

The PWM module 213 generates a PWM signal for controlling the power module 214 according to the modulation parameter outputted from the voltage/current PI control module 212. The power module 214 generates an output voltage based on the PWM signal generated by the PWM module 213.

For the DC voltage sources 220-2N 0, reference is also made to the above.

Therefore, by the mode, the actual output voltage and the output current of the direct current voltage source can be utilized to control the direct current voltage source, and therefore the stability of the output of the direct current voltage source is favorably adjusted.

In addition, optionally, referring to FIGS. 1 and 2, the DC voltage source system further comprises a DC bus 300, wherein the DC bus 300 is connected with the output ends of the plurality of DC voltage sources 210-2N 0. So that the electric energy generated by the dc voltage source system can be transmitted using the dc bus 300.

In addition, optionally, referring to fig. 1 and fig. 2, the dc voltage source system further includes a communication bus 400, and the communication bus 400 is connected to the main control module 100 and the plurality of dc voltage sources 210 to 2N0, respectively.

In addition, referring to FIG. 4, according to a second aspect of the present embodiment, a method for controlling a plurality of DC voltage sources 210-2N 0 connected in parallel is provided, which is applied to a main control module 110 for controlling the plurality of DC voltage sources 210-2N 0. The DC voltage sources 210-2N 0 include droop control modules 211-2N 1 for droop control, and the droop control modules 211-2N 1 are configured to control droop of the respective DC voltage sources 210-2N 0 according to a first set voltage value Vs received from the main control module 100, an output voltage value Vout of the DC voltage sources 210-2N 0, and voltage source output current values Iout 1-IoutN output by the respective DC voltage sources 210-2N 0. The method comprises the following steps:

s402: receiving an input second set voltage value Vset, wherein the second set voltage value Vset is used for indicating a voltage to be output by the DC voltage sources 210-2N 0; and

s404: the first set voltage value Vs is determined by compensating the second set voltage value Vset according to a difference between the second set voltage value Vset and the output voltage value Vout of the DC voltage sources 210-2N 0.

Alternatively, the operation of determining the first set voltage value Vs by compensating the second set voltage value Vset according to a difference between the second set voltage value Vset and the output voltage value Vout of the DC voltage source 210-2N 0 includes:

performing proportional integral operation according to a difference value between the second set voltage value Vset and an output voltage value Vout of the DC voltage source 210-2N 0 to determine a first control voltage value Vc as an operation result; and summing the second set voltage value Vset and the first control voltage value Vc to determine a first set voltage value Vs.

Furthermore, according to a third aspect of the present embodiment, there is provided a storage medium comprising a stored program, wherein the method of any one of the above is performed by a processor when the program is run.

The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one type of division of logical functions, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The above description is only for the preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A dc voltage source system, comprising: a master control module (100); and a plurality of dc voltage sources (210, 220.,. 2N 0) communicatively connected to the master control module (100), wherein the plurality of dc voltage sources (210, 220.,. 2N 0) are arranged in parallel, and the dc voltage sources (210, 220.,. 2N 0) comprise a droop control module (211, 221.... 2N 1) for droop control, the droop control module (211, 221.... 2N 1) being configured for outputting a system output voltage value (Vout) according to a first set voltage value (Vs) received from the master control module (100), the system output voltage value (Vout) output by the dc voltage source system, and a voltage source output current value (Iout 1, Iout2,. erut.. N.) for the respective dc voltage source (210, 220.,. 2N.. 3), the respective dc voltage source (210, 220.,. 2N 0). 2N 0), characterized in that,

the master control module (100) is further configured to:

receiving an input second set voltage value (Vset), wherein the second set voltage value (Vset) is used for indicating a voltage to be output by the direct current voltage source system; and

-determining the first set voltage value (Vs) by compensating the second set voltage value (Vset) according to a difference between the second set voltage value (Vset) and the system output voltage value (Vout);

wherein the operation of determining the first set voltage value (Vs) by compensating the second set voltage value (Vset) according to a difference between the second set voltage value (Vset) and the system output voltage value (Vout) comprises:

performing a proportional integral operation according to a difference between the second set voltage value (Vset) and the system output voltage value (Vout) to determine a first control voltage value (Vc) as a result of the operation; and

-summing said second set voltage value (Vset) and said first control voltage value (Vc), determining said first set voltage value (Vs);

the master control module (100) is further configured to: determining an average power value (Pav) of the plurality of direct current voltage sources (210, 220.., 2N 0); and sending the average power value (Pav) to the plurality of direct current voltage sources (210, 220.., 2N 0), and

the droop control module (211, 221,......., 2N 1) is further configured to droop control the respective dc voltage source (210, 220,...,2N 0) according to the first set voltage value (Vs) and the average power value (Pav) received from the master control module (100), the system output voltage value (Vout), and the respective voltage source output current value (Iout 1, Iout2,....., IoutN);

the droop control module (211, 221,......., 2N 1) performs droop control operations on the respective dc voltage source (210, 220,...,2N 0) according to the first set voltage value (Vs) and the average power value (Pav) received from the main control module (100), the system output voltage value (Vout), and the respective voltage source output current value (Iout 1, Iout2,....., IoutN), including:

determining respective voltage source output powers (Pout1, Pout 2...... multidot.poutn) from the system output voltage value (Vout) and respective voltage source output current values (Iout 1, Iout 2.. multidot.. multidot.ioutn);

performing a proportional integral operation on the difference between the average power value (Pav) and the respective voltage source output power (Pout1, Pout 2......, PoutN), and determining a respective second control voltage value (Vav 1, Vav 2......, VavN);

summing the first set voltage value (Vs) and the respective second control voltage value (Vav 1, Vav 2.. 9.., VavN), determining a respective first reference voltage value (Vr 1, Vr 2.. VrN);

determining respective third control voltage values (Vdr 1, Vdr 2.... multidot.vdrn) from the respective voltage source output powers (Pout1, Pout 2.. multidot.natured, PoutN) and the respective droop coefficients (K1, K2.. multidot.natured, KN); and

differences between the respective first reference voltage values (Vr 1, Vr 2........ VrN) and the respective third control voltage values (Vdr 1, Vdr 2...... prot., VdrN) are calculated, and respective second reference voltage values (Vref 1, Vref 2...... prot., VrefN) are determined.

2. The dc voltage source system according to claim 1, wherein a droop coefficient (K1, K2, K.. said., KN) of each droop control module (211, 221, 2N 1) satisfies the following condition:

the droop coefficient (K1, K2, a.... said, KN) of each droop control module (211, 221, a.... so, 2N 1) is equal to the product of the voltage source rated power (Pn 1, Pn2, a.. so, PnN) of the corresponding dc voltage source (210, 220, a.., 2N 0); and is

The output power of the dc voltage source system is a weighted sum of the voltage source output powers (Pout1, Pout 2...., PoutN) of the respective dc voltage sources (210, 220.., 2N 0), and the weighting value for each dc voltage source (210, 220.., 2N 0) is a respective droop coefficient (K1, K2.., KN).

3. The dc voltage source system of claim 2, wherein the dc voltage source (210, 220.., 2N 0) further comprises: a voltage-current PI control module (212, 222, a. ·..,2N 2), a PWM module (213, 223, a...., 2N 3), and a power module (214, 224, a...., 2N 4), wherein

The voltage and current PI control module (212, 222, a......, 2N 2) is connected with a droop control module (211, 221, a......, 2N 1) of a respective direct-current voltage source (210, 220, a......, 2N 0), and is configured to perform voltage PI control and current PI control according to a second reference voltage value (Vref 1, Vref2, a...., Vrefn 1) output by the respective droop control module (211, 221, a......, 2N 1) to generate a modulation parameter for controlling the respective PWM module (213, 223, a...., 2N 3);

the PWM modules (213, 223,......, 2N 3) are connected with the respective voltage and current PI control modules (212, 222,......, 2N 2) and configured to generate PWM signals for controlling the respective power modules (214, 224,...., 2N 4) according to modulation parameters output by the respective voltage and current PI control modules (212, 222,......, 2N 2); and

the power modules (214, 224, 2N 4) are connected to respective PWM modules (213, 223, 2N 3) and configured to generate respective output voltages in accordance with PWM signals generated by the respective PWM modules (213, 223, 2N 3).

4. The DC voltage source system according to any of claims 1 to 3, further comprising a DC bus (300), said DC bus (300) being connected to the output of said plurality of DC voltage sources (210, 220.., 2N 0).

5. The DC voltage source system according to any of claims 1 to 3, further comprising a communication bus (400), wherein the communication bus (400) is connected to the master control module (100) and the plurality of DC voltage sources (210, 220.., 2N 0), respectively.

6. A method of controlling a plurality of DC voltage sources (210, 220.., 2N 0) connected in parallel, for use in a master control module (100) controlling the plurality of DC voltage sources (210, 220.., 2N 0), wherein the DC voltage sources (210, 220., 2N 0) comprise a droop control module (211, 221.., 2N 1) for droop control, the droop control module (211, 221.., 2N 1) being configured for controlling a droop current value (I | 1, I.. 2, D.C. voltage source (210, 220.., 2N 0) and a voltage source output current value (I | Vout) output by the respective DC voltage source (210, 220.., 2N 0) in dependence on a first set voltage value (Vs) received from the master control module (100), an output voltage value (I | UT) of the DC voltage source (210, 220.., 2N 0) and the respective DC voltage source (210, 220.., 2N 0), ..,2N 0), the method comprising:

receiving an input second set voltage value (Vset), wherein the second set voltage value (Vset) is indicative of a voltage to be output by the dc voltage source (210, 220.., 2N 0); and

-compensating the second set voltage value (Vset) according to a difference between the second set voltage value (Vset) and an output voltage value (Vout) of the direct voltage source (210, 220., 2N 0), -determining the first set voltage value (Vs).

7. A storage medium comprising a stored program, wherein the method of claim 6 is performed by a processor when the program is run.