WO2021017337A1

WO2021017337A1 - Energy control circuit and control method therefor

Info

Publication number: WO2021017337A1
Application number: PCT/CN2019/120881
Authority: WO
Inventors: 高冲; 张静; 贺之渊; 许彬; 赵岩; 盛财旺; 周建辉; 张娟娟; 李婷婷; 乔丽
Original assignee: 全球能源互联网研究院有限公司
Priority date: 2019-07-31
Filing date: 2019-11-26
Publication date: 2021-02-04
Also published as: CN110460228A

Abstract

Disclosed are an energy control circuit and a control method therefor. The control method for the energy control circuit comprises: determining input amount of a plurality of voltage source modules in the energy control circuit according to energy consumption requirements; controlling, according to the input amount, a main switch in the energy control circuit, in parallel connection with the voltage source module(s) to be used, to be turned off, adjusting the voltage source module(s) to be used into a voltage division state and maintaining the stability of the voltage division of the voltage source module(s) to be used, and controlling a main resistor in the energy control circuit to consume energy according to the energy consumption requirements; controlling a main switch, in parallel connection with the plurality of voltage source modules except for the voltage source module(s) to be used, to be turned on, and adjusting the plurality of voltage source modules except for the voltage source module(s) to be used to be in a short-circuited state; and controlling, on the basis of the input amount, the plurality of voltage source modules to be alternately turned on and off within a set operating period.

Description

Energy control circuit and its control method

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office with application number 201910701825.9 on July 31, 2019. The entire content of this application is incorporated into this application by reference.

Technical field

This application relates to the field of DC transmission energy transfer, for example, to an energy control circuit and a control method thereof.

Background technique

The DC transmission line can efficiently and conveniently transfer a large amount of electric energy from the energy base to the load center. The structure diagram of the DC transmission line is shown in Figure 2. For a DC transmission project in operation, the energy absorbed by the receiving end is compared with the energy emitted by the sending end. The power phase is balanced, and the voltage and operating frequency of the power grid at the sending end remain constant. When the power system at the receiving end is disturbed or faulty and cannot absorb the electric energy sent by the sending end, the voltage and frequency of the sending end grid will be disturbed. This disturbance can be reduced by quickly adjusting the output of the generator; if the power supply at the sending end is Thermal generators or hydroelectric generators, the output of the generator can be adjusted, but the adjustment process requires a certain time delay and cannot achieve immediate response. The voltage and frequency of the power grid will still be disturbed; if the sending end power is a wind turbine, because The natural wind cannot be controlled, and the output of the wind turbine cannot be adjusted according to the operation needs. The voltage and frequency of the sending-end power grid will be severely disturbed. In severe cases, the generator set may break and cause serious grid accidents.

The development of UHV DC transmission technology has increased the transmission capacity of DC transmission to 8000MW～12000MW. The traditional firepower and hydroelectric generator installed capacity of the sending-end power grid will increase accordingly. The rapid adjustment of generator output is becoming increasingly difficult. Wind, light, water, This difficulty is compounded by bundled thermal power transmission; the development of flexible DC transmission technology has made the scale of wind power grid-connected increasingly expanded, and the grid failure at the receiving end caused the power mismatch between the sending end and the receiving end, causing the wind turbine to split The risks are increasing.

In order to solve the above problems and improve the operational reliability of DC transmission, it is necessary to design an energy control circuit to maintain the power balance between the sending end and the receiving end of the entire DC transmission system.

There are three types of energy control circuits. Among the three energy control circuits, circuit 1 uses a switch in series with a resistor. As shown in Figure 3, the switch is a valve composed of power electronic devices in series. The opening of the valve is controlled by pulse width modulation (PWM). The circuit has the characteristics of simple structure and easy control. However, when the DC voltage rises to a certain level, the increase in the number of power electronic devices will make it difficult to balance the voltage of the devices, due to the use of pulse width In the modulation method, the consistency of actions of all power electronic devices cannot be guaranteed; therefore, this circuit is suitable for low-voltage fields. Circuit 2 has a modular design on the basis of circuit 1. As shown in Figure 4, the control method of circuit 2 is: distributing switches and resistors in each module, and the voltage equalization of the modules is realized by the module capacitors. The number of module switches that are turned on controls the power consumed by the circuit; this circuit has the advantages of simple control mode and not limited by DC voltage. The disadvantage is that the energy-consuming resistor is placed in the module, which will increase the volume of the module and the building of the valve hall. The area requires high cooling system. Compared with circuit 1, the improvement of circuit 3 is that the switch valve adopts modular multilevel converter (Modular Multilevel Converter, MMC) modules in series, as shown in Figure 5, the modular multilevel converter module can be Using a full-bridge or half-bridge structure, the control method of circuit 3 is: the module voltage can be equalized by charging and discharging the capacitor of the modular multi-level converter module, and the modular multi-level converter module is not necessary when the control circuit is activated At the same time, the circuit is switched on and off, so the circuit is not limited by DC voltage and can be applied to high-voltage projects; the disadvantage of the control method of the circuit is that the control method is complicated and the equipment cost is high.

Summary of the invention

This application provides an energy control circuit and a control method thereof to solve the problem of lack of an energy control method suitable for high-voltage DC lines in the related art.

This application provides an energy control circuit, including:

Main resistance, multiple main switches and multiple voltage source modules;

The main switch is connected in parallel with the voltage source module;

The main resistor is connected in series with a plurality of voltage source modules;

The multiple voltage source modules are set to be connected to the DC transmission line, and obtain the voltage of the DC transmission line on average under charging;

Wherein, the power consumed by the main resistor is greater than the power consumed by the multiple voltage source modules.

The application also provides a control method of an energy control circuit, including:

According to energy consumption requirements, determine the input amount of multiple voltage source modules in the energy control circuit;

According to the input amount, control the main switch of the energy control circuit in parallel with the voltage source module to be input to be turned off, adjust the voltage source module to be input to the divided voltage state and maintain the divided voltage of the voltage source module to be input Stable, controlling the main resistance in the energy control circuit to consume energy according to the energy consumption demand; controlling the main switch connected in parallel with the voltage source module of the plurality of voltage source modules except the voltage source module that needs to be put in Closed, adjusting the voltage source modules of the plurality of voltage source modules except the voltage source modules that need to be put into short-circuit state;

In a set working period, the multiple voltage source modules are controlled to alternately switch on and off based on the input amount.

Description of the drawings

FIG. 1 is a structural diagram of an energy control circuit based on a resistance container provided by an embodiment of the application;

Figure 2 is a structural diagram of a DC transmission line in related technologies;

Figure 3 is a structural diagram of the circuit 1 in the related art;

Figure 4 is a structural diagram of circuit 2 in the related art;

Figure 5 is a structural diagram of circuit 3 in the related art;

6 is a symmetrical connection diagram of an energy control circuit provided by an embodiment of the application;

FIG. 7 is a first topology structure diagram of a voltage source module provided by an embodiment of the application;

FIG. 8 is a second topology structure diagram of a voltage source module provided by an embodiment of this application;

FIG. 9 is a third topology structure diagram of a voltage source module provided by an embodiment of the application;

FIG. 10 is a fourth topological structure diagram of a voltage source module provided by an embodiment of this application;

FIG. 11 is a flowchart of a control method of an energy control circuit provided by an embodiment of the application.

Among them, 1-converter transformer; 2-converter; 3-AC filter; 4-smoothing reactor; 5-DC filter; 6-converter station outside cooling system.

Detailed ways

The content of this application will be described below with reference to the drawings and examples of the specification.

Example one

This embodiment provides an energy control circuit based on a resistance vessel. The circuit structure is shown in FIG. 1. The energy control circuit includes a main resistor R _m , a main switch K _m and a voltage source module.

In this embodiment, FIG. 1 only shows a form of parallel connection of a main switch and a voltage source module, that is, a main switch and a voltage source module are connected in parallel. In addition, the main switch in this application is connected in parallel with the voltage source module. The form also includes: multiple voltage source modules connected in series and connected in parallel with a main switch; multiple main switches connected in series and connected in parallel with a voltage source module; multiple voltage source modules connected in series, multiple main switches connected in series, multiple voltage sources connected in series The modules are connected in parallel with multiple main switches connected in series.

In this embodiment, the power consumed by the main resistor is greater than the power consumed by the multiple voltage source modules. In an embodiment, the power consumed by the main resistor is approximately several hundred times the power consumed by the voltage source of each sub-module.

In an embodiment, the energy control circuit further includes an inductor L _m .

In an embodiment, the energy control circuit is asymmetrical or symmetrical.

In one embodiment, the topological structure of the voltage source module is shown in Figures 7 and 8. The principle is: a topological circuit composed of a direct current (DC)/DC step-down conversion circuit and a resistor or a DC/DC step-down conversion circuit In a topology circuit composed of a battery, the voltage source module includes: a voltage source, an auxiliary switch, an auxiliary resistor, and a control sub-module; the auxiliary switch and the auxiliary resistor are connected in series to form an auxiliary circuit; the voltage source and the auxiliary circuit are connected in parallel; the control The sub-module is connected to the voltage source and the auxiliary switch, and is configured to control the closing and opening of the auxiliary switch according to the voltage across the voltage source; the voltage source is a capacitor or a battery.

For the topological structure of the voltage source module of FIG. 7 or FIG. 8, the energy control circuit further includes: a plurality of first diodes, a plurality of second diodes, and a plurality of third diodes; The diode is connected in anti-parallel with a main switch; each second diode is connected in series with a voltage source module; each third diode is connected in anti-parallel with an auxiliary switch.

The topology of the voltage source module can also be shown in Figure 9. The principle is a topology circuit composed of a DC/AC (Alternating Current, AC) half-bridge conversion circuit and a voltage source. The voltage source module includes: two voltage sources, two Auxiliary switch, auxiliary resistance and control sub-module; the two voltage sources are connected in series to form a first series circuit; the two auxiliary switches are connected in series to form a second series circuit; the center point of the first series circuit is connected to the The center point of the second series circuit is connected through the auxiliary resistor; the control sub-module is connected to the two voltage sources and two auxiliary switches, and is configured to control the two voltage sources according to the voltages across the two voltage sources. The closing and opening of two auxiliary switches; the two voltage sources are capacitors.

For the topological structure of the voltage source module in FIG. 9, the energy control circuit further includes: multiple fourth diodes, multiple fifth diodes, and multiple sixth diodes; each fourth diode It is connected in reverse parallel with a main switch; each fifth diode is connected in series with a voltage source module; each sixth diode is connected in reverse parallel with an auxiliary switch.

The topological structure of the voltage source module can also be shown in Figure 10. The principle is a topological circuit composed of a DC/AC full bridge conversion circuit and a voltage source. The voltage source module includes: a voltage source, four auxiliary switches, an auxiliary resistor, and a control sub Module. The four auxiliary switches are connected in series in pairs to obtain two series circuits, and the two series circuits are connected in parallel with the voltage source; the center points of the two series circuits are connected through the auxiliary resistor; the control submodule is connected to the voltage source and The four auxiliary switches are connected and set to control the closing and opening of the four auxiliary switches according to the voltage across the voltage source. The voltage source is a capacitor.

For the topological structure of the voltage source module in FIG. 10, the energy control circuit further includes: multiple seventh diodes, multiple eighth diodes, and multiple ninth diodes; each seventh diode It is connected in reverse parallel with a main switch; each eighth diode is connected in series with a voltage source module; each ninth diode is connected in reverse parallel with an auxiliary switch.

In one embodiment, the resistance of each main resistor is determined by the preset maximum power consumption value of the energy control circuit and the voltage of the DC transmission line, and the resistance of each main resistor is calculated as follows:

Wherein, R _{m_usy} is the resistance of each main resistor when the energy control circuit is arranged asymmetrically, R _{m_sy} is the resistance of each main resistor when the energy control circuit is arranged symmetrically, P _max is the preset maximum power consumption value of the energy control circuit, and U _dc is the voltage of the DC transmission line.

In an embodiment, the minimum number of the multiple voltage source modules arranged in the energy control circuit is determined by the withstand voltage capability of each main switch and the voltage of the DC transmission line, and the calculation formula is as follows:

Wherein, N _{m_min_usy} is the minimum number of the plurality of voltage source modules when the energy control circuit is arranged asymmetrically, and N _{m_min_sy} is when the energy control circuit is arranged symmetrically, the plurality of voltages The minimum number of source modules, U _dc is the voltage of the DC transmission line, and U _{m_e} is the withstand voltage of each main switch.

In the case where the power control circuit is in a hot standby state, the DC voltage U _dc transmission line is evenly distributed on each voltage source module, each of the voltage source voltage U _mo module _{_{= U dc / N T, N}} T is a voltage source The total number of modules.

When all the main switches K _{m are} closed, the power consumed by the energy control circuit is equal to the rated power of the DC system. There are:

Let the power command of the energy control circuit be duty (0≤duty≤1), and the number of voltage source modules N _on that needs to be input is: N _on =N _T ×(1-duty).

In the case of 0.5<duty≤1, the time length T _arr of the N _on voltage source modules input is:

T _ch is the set duty cycle.

In the case of 0≤duty≤0.5, the duration T _arr of the N _on voltage source modules input is:

When a voltage source module is put into use, the voltage source of the voltage source module is charged, the voltage rises, and the voltage source of the voltage source module is controlled to discharge and the voltage drops; the voltage of each voltage source module will be monitored in real time , Set a hysteresis control link, the control logic is as follows:

In> _U _Ca U Ca_c case, the voltage source voltage source module discharges the capacitor C _a voltage source module voltage drop, U _Ca C _a voltage, the upper limit of the voltage fluctuation _U Ca_c of C _a.

In the case where _{_U} Ca_f ≤U _Ca ≤U Ca_c, the voltage source voltage source module continues to be discharged, C _a voltage continues to _drop, U Ca_f C _a is the lower limit of the voltage fluctuation.

In the case of U _Ca <U _{Ca_f} , the voltage source of the voltage source module stops discharging and starts the next cycle.

The sum of the charging time t _ch and the discharging time t _dis of the capacitor of the voltage source module should be greater than the input time of the voltage source module, and the following relationship must be satisfied: t _ch +t _dis >(1-duty)×T _ch . T _ch is the set duty cycle.

When the power command takes different values, the power P _Rm of the main resistance R _m is:

I _ch is the current of the entire chopper branch. I _N is to remove all voltage source modules in the DC transmission line, and when the main resistance R _{m is} directly connected to both ends of the DC transmission line, the current passing through the main resistance R _m (the power consumed by the energy control circuit is equal to the DC transmission line Rated power).

The total power P _{Ra_T} consumed by the auxiliary resistors of the _NT voltage source modules is:

The power P _Ra consumed by the auxiliary resistor of each voltage source module is: P _Ra =P _N duty (1-duty)/N _T.

The energy control circuit provided by the present application includes: a main resistor, multiple main switches, and multiple voltage source modules; each main switch is connected in parallel with a voltage source module; the main resistor is connected in series with multiple voltage source modules; Multiple voltage source modules are set to divide the voltage of the energy control circuit under charging; this solution uses multiple voltage source modules to control the voltage division of the circuit, so that the current in the energy control circuit is smoothed and energy is carried out through the main resistance. Consumption. In this scheme, the voltage source is modular, the circuit structure is simple, and the area is small.

Example two

This embodiment provides a method for controlling an energy control circuit. The method flowchart is shown in FIG. 11, and the method includes:

S10: Determine the input amount of multiple voltage source modules in the energy control circuit according to the energy consumption demand.

S20: According to the input amount, control the main switch in the energy control circuit in parallel with the voltage source module that needs to be input to disconnect, adjust the voltage source module that needs to be input to the divided voltage state and maintain the voltage source module that needs to be input. The voltage division is stable, and the main resistor in the energy control circuit consumes energy according to the energy consumption demand; controls the main resistor connected in parallel with the voltage source module of the plurality of voltage source modules except the voltage source module that needs to be input The switch is closed, and the voltage source modules other than the voltage source modules that need to be put into the multiple voltage source modules are adjusted to a short-circuit state.

S30: In a set working period, control the multiple voltage source modules to alternately switch on and off based on the input amount.

According to the input amount, controlling the main switch connected in parallel with the voltage source module to be input in the energy control circuit to be turned off, and adjusting the voltage source module to be input to a voltage division state, includes: controlling the energy control circuit The main switch in parallel with the voltage source module that needs to be input is disconnected, the auxiliary switch in the voltage source module that needs to be input is controlled to be disconnected, and the voltage source in the voltage source module that needs to be input is connected in series to the DC transmission line. Partial pressure.

Maintaining a stable partial voltage of the voltage source module that needs to be input includes: maintaining the voltage source module that needs to be input in parallel when the voltage source module that needs to be input reaches a first threshold. The main switch is turned off and the voltage source module that needs to be input is adjusted to the protection state to perform voltage reduction; when the partial voltage of the voltage source module that needs to be input drops to a second threshold, the The main switch connected in parallel of the voltage source module that needs to be input is turned off and the voltage source module that needs to be input is adjusted to a voltage division state for voltage division; the second threshold is the first threshold.

In the case where the partial voltage of the voltage source module that needs to be input reaches a first threshold, the main switch connected in parallel with the voltage source module that needs to be input is kept off and the voltage source module that needs to be input Adjusting to the protection state and stepping down includes: monitoring the voltage across the voltage source of the voltage source module that needs to be input through the control sub-module of the voltage source module that needs to be input; When the voltage across the voltage source reaches the first threshold, the main switch of the voltage source module that needs to be input is kept disconnected, and the control sub-module controls the auxiliary switch of the voltage source module that needs to be input to close, so The voltage source of the voltage source module that needs to be input is discharged and reduced.

In the case where the partial voltage of the voltage source module that needs to be input falls to a second threshold, the main switch connected in parallel with the voltage source module that needs to be input is kept off and the voltage source module that needs to be input is adjusted In the voltage division state, performing voltage division includes: monitoring the voltage across the voltage source of the voltage source module that needs to be input through the control submodule of the voltage source module that needs to be input; When the voltage across the voltage source drops to the second threshold, keep the main switch connected in parallel with the voltage source module that needs to be turned off, and control the auxiliary switch of the voltage source module that needs to be turned off through the control sub-module On, the voltage source is connected in series to the DC transmission line for voltage division.

The adjusting the voltage source modules of the plurality of voltage source modules except the voltage source modules that need to be put into a short-circuit state includes: controlling and controlling the voltage source modules other than the voltage source modules that need to be put into the plurality of voltage source modules The main switch of the voltage source modules connected in parallel is closed, and the voltage source modules of the plurality of voltage source modules except the voltage source modules that need to be put in are short-circuited.

The controlling the multiple voltage source modules to switch on and off alternately based on the input amount during the set working period includes: determining all the voltage source modules according to the energy consumption demand and the input amount during the set work period The input duration of the multiple voltage source modules; based on the input duration, all main switches are controlled to be turned on and off once, so as to realize the alternate switching on and off of the multiple voltage source modules.

The investment time is determined by the following formula:

In the above formula, duty is energy consumption demand, T _arr is the duration of input, and N _on is the number of voltage source modules that need to be input. N _T is the total number of the multiple voltage source modules, and T _ch is the set duty cycle.

The determining the input amount of the multiple voltage source modules in the energy control circuit according to the energy consumption demand includes: determining the multiple voltage source modules based on the energy consumption demand and the voltage division amount of each voltage source module The input amount of the voltage source module, the calculation formula of the input amount is shown in the following formula:

In the above formula, _{Non_usy} is the input amount of multiple voltage source modules when the energy control circuit is set asymmetrically, and _{Non_sy} is the input amount of the voltage source module when the energy control circuit is set symmetrically, U _dc is For the voltage of the DC transmission line, U _mo is the voltage division of the voltage source in each voltage source module, and duty is the energy demand, 0≤duty≤1.

The controlling the alternate switching on and off of the multiple voltage source modules based on the input amount during the set working period includes: changing the charging time and discharging time of the voltage sources in the multiple voltage source modules to make The auxiliary switches in the multiple voltage source modules are turned on and off once in a set working period.

The auxiliary switch in the voltage source module is turned on and off once in a set working period, and the charging time and discharging time of the voltage source should satisfy the following formula:

t _ch +t _dis ＞(1-duty)×T _ch

In the above formula, t _ch is the charging time of the voltage sources in the multiple voltage source modules, t _dis is the discharge time of the voltage sources in the multiple voltage source modules, duty is the energy consumption demand, and T _ch is the set duty cycle .

The control method provided by the present application determines the input amount of multiple voltage source modules in the energy control circuit according to the energy consumption demand; according to the input amount, the main switch in the energy control circuit is controlled to be turned off, and the required input The voltage source module is adjusted to a divided voltage state and the divided voltage of the voltage source module that needs to be input is maintained stable. The main resistance in the energy control circuit consumes energy according to the energy consumption demand; controls the main switch to close, and Among the voltage source modules, the voltage source modules other than the voltage source modules that need to be input are adjusted to a short-circuit state; in a set working period, the multiple voltage source modules are controlled to alternately switch on and back based on the input amount. In this solution, the voltage source module is controlled to alternately switch on and back within the set working period, so that the voltage source module in the energy control circuit is alternately cooled, which reduces the hardware loss rate.

Example three

This embodiment provides an energy control method. The method includes the following steps:

Step 110: When the energy control circuit is in the hot standby state, use the voltage of the DC transmission line to charge the voltage source of each voltage source module.

Step 120: The voltage of the voltage source of each voltage source module will be monitored in real time, and the hysteresis control logic is designed to make the voltage of the voltage source of the voltage source module fluctuate around a certain value.

Step 130: Determine the number of input voltage source modules according to the power command of the energy absorption circuit.

Step 140: In a working cycle, the voltage source modules alternately switch on and off to ensure that the power of the energy control circuit is equally distributed among the voltage source modules and the main switch K _{m in} parallel with the voltage source module is switched on only once.

Step 150, if the voltage source voltage source module using a selected capacitance value of the capacitor, a voltage source module may be guaranteed in the case of duty for different values of the auxiliary switch K _a only switch once, or according to the actual demand for flexible control of the auxiliary switch K _a switching frequency.

Step 160: The maximum power of the main resistor R _m is equal to the rated power P _{N of the} DC system, and the maximum power of all sub-module resistors is equal to 25% of the rated power P _N of the DC system.

In one embodiment, the power control circuit comprising: a main resistance R _m, K _m of the main switch, and a voltage source module inductance L _m, each voltage source by the auxiliary switch block K _a, and the auxiliary voltage source resistance R _a composition.

In one embodiment, in step 110, when the energy control circuit is in a hot standby state, the voltage U _{dc of the} DC transmission line is evenly distributed on each voltage source module, so the voltage U _{mo of} each voltage source module = U _dc /N _T.

In one embodiment, in step 120, when each voltage source module is put into operation, the voltage source of the voltage source module is charged, the voltage is increased, and the voltage source of the voltage source module is controlled to discharge and the voltage is decreased; The voltage of the source module voltage source will be monitored in real time, a hysteresis control link is set, and the control logic is as follows:

In> _U _Ca U Ca_c case, the voltage source voltage source module discharges, C _a voltage drop.

In the case where _{_U} Ca_f ≤U _Ca ≤U Ca_c, the sub-modules continue to discharge the voltage source, C _a voltage continues to drop.

The above control logic can ensure that the capacitor voltage of the voltage source module fluctuates near U _{mo_h} , and U _{mo_h} is the average voltage of the voltage source module.

In one embodiment, in the step 130, when all the main switches K _{m are} closed, the power consumed by the energy control circuit is equal to the rated power of the DC system, as follows:

The number of voltage source modules that need to be input N _on can be determined according to the power command duty.

In one embodiment, in step 140, when duty takes different values, in order to ensure that the power of the energy control circuit is evenly distributed in the voltage source module during each work cycle of the energy control circuit, each main switch K _m Only switch once, and design the following control logic:

In one embodiment, in step 150, if the voltage source of the voltage source module adopts a capacitor, in order to reduce the switching loss of an insulated gate bipolar transistor (IGBT), the design is designed when the duty is different. auxiliary switch K _a only switch 1, the capacitor charging time voltage source module t _ch discharge time t _dis sum investment of time should be greater than the voltage source module must meet the following _{_{relationship: t ch + t dis> (}} 1-duty )×T _ch .

May be based on actual needs, the voltage source module is reduced by reducing the charging time of the capacitor module capacitance value of the voltage source and the discharge time t _ch t _dis sum K _a flexible control of the switching frequency of the auxiliary switch.

In one embodiment, in step 160, when the power command is duty, the current I _ch through the entire chopper branch is: I _ch =I _N ×duty.

Then the power P _Rm of the main resistance R _m is:

In the case of duty=1, the power of the main resistance is equal to the rated power of the DC system, and the power of the main resistance is proportional to the second power of the duty. The power of the main resistance will decrease rapidly as the duty decreases.

In the case of duty=0.5, P _{Ra_T} reaches the maximum value of 0.25P _N , and the maximum power consumed by the auxiliary resistor of each voltage source module is 0.25P _N /N _t .

Example four

Take a DC project as an example, the rated DC voltage of the project U _dc =±320kV, the energy control circuit adopts a symmetrical arrangement, the maximum power that the energy control circuit needs to consume is P _max ＝900MW, and the unipolar power is P _{max_s} ＝P _N ＝450MW , It can be obtained that the main resistance value R _m =227.5Ω; the number of voltage source modules N _T =128, the main switch K _m withstand voltage is U _{m_e} =2.5kV, and the auxiliary resistance of the voltage source module _Ra =1.56Ω, The working frequency of the energy control circuit f _ch ＝200Hz, the duty cycle T _ch ＝0.005s; the voltage source of the voltage source module adopts a capacitor, the lower limit of the voltage fluctuation of the capacitor C _a is U _{Ca_f} ＝2.2kV, the voltage of the capacitor C _{a of the} voltage source module The upper limit of fluctuation U _{Ca_c} =2.7kV, it can be concluded that the capacitance of the voltage source module C _a >2.4mF.

Let duty=0.7, the number of voltage source modules that need to be input N _on ＝128×(1－0.7)=38.4, take the integer value 38; the duration of the input 38 voltage source modules T _arr ＝0.005×38/128=0.015 s, after 0.0015s, switch to the subsequent 38 voltage source modules, and so on; the power of the main resistor R _m P _Rm =P _N ×0.7 ² =220.5MW, the total power consumed by the auxiliary resistor of the voltage source module P _{Ra_T} = P _N ×0.7×(1-0.7)=94.5MW, the power consumed by the auxiliary resistor of each voltage source module is P _Ra =P _{Ra_T} /128=0.7383MW.

The embodiments described herein are a part of the embodiments of this application, but not all of the embodiments. The embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this application can be used in one or more computer-usable storage media (including but not limited to magnetic disk storage, Compact Disc Read-Only Memory (CD-ROM), optical storage, etc.) containing computer-usable program codes. ) In the form of a computer program product implemented on it.

This application is described with reference to flowcharts and/or block diagrams of methods, equipment (systems), and computer program products according to the embodiments of this application. Each process and/or block in the flowchart and/or block diagram, and the combination of processes and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing equipment to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing equipment are generated It is a device that realizes the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device. The device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment. The instructions provide steps for implementing functions specified in a flow or multiple flows in the flowchart and/or a block or multiple blocks in the block diagram.

Claims

An energy control circuit, including:

Main resistance, multiple main switches and multiple voltage source modules;

The main switch is connected in parallel with the voltage source module;

The main resistor is connected in series with the plurality of voltage source modules in sequence;

The plurality of voltage source modules are configured to be connected to the DC transmission line, and obtain the voltage of the DC transmission line on average under charging;

Wherein, the power consumed by the main resistor is greater than the power consumed by the multiple voltage source modules.
The circuit of claim 1, wherein the energy control circuit is asymmetrical or symmetrical.
The circuit of claim 1 or 2, wherein each voltage source module includes:

Voltage source, auxiliary switch, auxiliary resistance and control sub-module;

The auxiliary switch and the auxiliary resistor are connected in series to form an auxiliary circuit;

The voltage source and the auxiliary circuit are connected in parallel;

The control sub-module is connected to the voltage source and the auxiliary switch, and is configured to control the closing and opening of the auxiliary switch according to the voltage across the voltage source;

The voltage source is a capacitor or a battery.
The circuit of claim 3, further comprising:

A plurality of first diodes, a plurality of second diodes, and a plurality of third diodes;

Each first diode is connected in reverse parallel with a main switch;

Each second diode is connected in series with a voltage source module;

Each third diode is connected in anti-parallel with an auxiliary switch.
The circuit of claim 1 or 2, wherein each voltage source module includes:

Two voltage sources, two auxiliary switches, auxiliary resistors and control sub-modules;

The two voltage sources are connected in series to form a first series circuit;

The two auxiliary switches are connected in series to form a second series circuit;

The center point of the first series circuit and the center point of the second series circuit are connected by the auxiliary resistor;

The control submodule is connected to the two voltage sources and the two auxiliary switches, and is configured to control the closing and opening of the two auxiliary switches according to the voltages at both ends of the two voltage sources;

The two voltage sources are capacitors.
The circuit of claim 5, further comprising:

Multiple fourth diodes, multiple fifth diodes, and multiple sixth diodes;

Each fourth diode is connected in anti-parallel with a main switch;

Each fifth diode is connected in series with a voltage source module;

Each sixth diode is connected in anti-parallel with an auxiliary switch.
The circuit of claim 1 or 2, wherein each voltage source module includes:

Voltage source, four auxiliary switches, auxiliary resistance and control sub-module;

The four auxiliary switches are connected in series in pairs to obtain two series circuits, and the two series circuits are both connected in parallel with the voltage source;

The center points of the two series circuits are connected by the auxiliary resistor;

The control sub-module is connected to the voltage source and the four auxiliary switches, and is configured to control the closing and opening of the four auxiliary switches according to the voltages across the four voltage sources;

The voltage source is a capacitor.
The circuit of claim 7, further comprising:

Multiple seventh diodes, multiple eighth diodes, and multiple ninth diodes;

Each seventh diode is connected in reverse parallel with a main switch;

Each eighth diode is connected in series with a voltage source module;

Each ninth diode is connected in anti-parallel with an auxiliary switch.
The circuit of any one of claims 2-8, wherein:

The resistance value of each main resistance is determined by the preset maximum power consumption value of the energy control circuit and the voltage of the DC transmission line, and the resistance value of each main resistance is calculated as follows:

The energy control circuit is arranged asymmetrically;

The energy control circuit is arranged symmetrically;

Wherein, R m_usy is the resistance of each main resistor when the energy control circuit is arranged asymmetrically, R m_sy is the resistance of each main resistor when the energy control circuit is arranged symmetrically, P max is the preset maximum power consumption value of the energy control circuit, and U dc is the voltage of the DC transmission line.
The circuit of any one of claims 2-9, wherein:

The minimum number of the multiple voltage source modules arranged in the energy control circuit is determined by the withstand voltage capability of each main switch and the voltage of the DC transmission line, and the calculation formula is as follows:

Wherein, N m_min_usy is the minimum number of the plurality of voltage source modules when the energy control circuit is arranged asymmetrically, and N m_min_sy is when the energy control circuit is arranged symmetrically, the plurality of voltages The minimum number of source modules, U dc is the voltage of the DC transmission line, and U m_e is the withstand voltage of each main switch.
The control method of the energy control circuit according to any one of claims 1-10, comprising:

Determining the input amount of the multiple voltage source modules in the energy control circuit according to the energy consumption demand;

According to the input amount, control the main switch in the energy control circuit in parallel with the voltage source module that needs to be input to open, adjust the voltage source module that needs to be input to a divided voltage state and maintain the voltage source that needs to be input The voltage division of the module is stable; the main switch connected in parallel with the voltage source module of the plurality of voltage source modules except the voltage source module that needs to be input is controlled to close, and the plurality of voltage source modules are removed from the voltage source module that needs to be input. Adjust the voltage source module outside the voltage source module to a short-circuit state;

In a set working period, the multiple voltage source modules are controlled to alternately switch on and off based on the input amount.
The method according to claim 11, wherein, according to the input amount, the main switch in the energy control circuit connected in parallel with the voltage source module that needs to be input is controlled to open, and the voltage source module that needs to be input is adjusted to be divided Pressure status, including:

Controlling the main switch in the energy control circuit connected in parallel with the voltage source module that needs to be turned off, and controlling the auxiliary switch in the voltage source module that needs to be turned off.
The method according to claim 11 or 12, wherein the maintaining a stable partial voltage of the voltage source module that needs to be input includes:

When the partial voltage of the voltage source module that needs to be input reaches the first threshold, the main switch connected in parallel with the voltage source module that needs to be input is kept off and the voltage source module that needs to be input is adjusted to Protection state, step-down;

When the partial voltage of the voltage source module that needs to be input falls to the second threshold, keep the main switch connected in parallel with the voltage source module that needs to be input off and adjust the voltage source module that needs to be input into Pressure state, partial pressure;

The second threshold is lower than the first threshold.
The method according to claim 13, wherein, when the partial voltage of the voltage source module that needs to be input reaches a first threshold, the main switch connected in parallel with the voltage source module that needs to be input is kept open and Adjusting the voltage source module that needs to be put into the protection state and stepping down includes:

Monitoring the voltage across the voltage source of the voltage source module that needs to be input through the control sub-module of the voltage source module that needs to be input;

When the voltage across the voltage source of the voltage source module that needs to be input reaches the first threshold, the main switch of the voltage source module that needs to be input is kept disconnected, and the control submodule controls the voltage source that needs to be input. The auxiliary switch of the voltage source module is closed, and the voltage source of the voltage source module that needs to be input is discharged and stepped down.
The method according to claim 13, wherein the main switch connected in parallel with the voltage source module that needs to be input is kept off when the partial voltage of the voltage source module that needs to be input falls to a second threshold And adjust the voltage source module that needs to be put into the voltage division state to perform voltage division, including:

Monitoring the voltage across the voltage source of the voltage source module that needs to be input through the control sub-module of the voltage source module that needs to be input;

When the voltage across the voltage source of the voltage source module that needs to be input is reduced to the second threshold, the main switch connected in parallel with the voltage source module that needs to be input is kept off, and the control sub-module controls the The auxiliary switch of the voltage source module that needs to be input is turned off.
15. The method according to any one of claims 11-15, wherein the adjusting the voltage source modules of the plurality of voltage source modules except the voltage source module to be put into a short-circuit state comprises:

The main switch connected in parallel with the voltage source module of the plurality of voltage source modules except the voltage source module that needs to be input is controlled to close, so that The voltage source module is short-circuited.
The method according to any one of claims 11-16, wherein the controlling the plurality of voltage source modules to alternately switch on and off based on the input amount within a set working period comprises:

Within a set working period, determine the input duration of the multiple voltage source modules according to the energy consumption demand and the input amount;

Based on the switching time, all the main switches are controlled to be turned on and off once, so as to realize the alternate switching on and off of the multiple voltage source modules.
The method of claim 17, wherein:

The investment time is determined by the following formula:

Where, duty is the energy demand, T arr input to the long, N on the number of the required input voltage source module, N T is the total number of said plurality of voltage sources modules, T ch is the Describe the set work cycle.
The method according to any one of claims 11-18, wherein the determining the input amount of the multiple voltage source modules in the energy control circuit according to the energy consumption demand comprises:

Based on the energy consumption demand and the voltage division amount of the voltage source in each voltage source module, the input amount of the multiple voltage source modules is determined, and the calculation formula of the input amount is as follows:

Wherein, Non_usy is the input amount of the multiple voltage source modules when the energy control circuit is arranged asymmetrically, and Non_sy is the input amount of the multiple voltage source modules when the energy control circuit is arranged symmetrically, The input amount of the module, U dc is the voltage of the DC transmission line, U mo is the voltage division of the voltage source in each voltage source module, and duty is the energy consumption demand, 0≤duty≤1.
The method of claim 11, wherein the controlling the alternate switching on and off of the plurality of voltage source modules based on the input amount within a set working period comprises:

By changing the charging time and the discharging time of the voltage sources in the multiple voltage source modules, the auxiliary switches in the multiple voltage source modules are turned on and off once in the set working period.
The method of claim 20, wherein:

In the case that the auxiliary switches in the multiple voltage source modules are turned on and off once within the set working period, the charging time and discharging time of the voltage sources in the multiple voltage source modules meet the following requirements formula:

t ch +t dis ＞(1-duty)×T ch ;

Wherein, t ch is the charging time of the voltage source in the plurality of voltage source modules, t dis is the discharging time of the voltage source in the plurality of voltage source modules, duty is the energy consumption demand, and T ch is all Describe the set work cycle.