WO2020094030A1

WO2020094030A1 - Energy-consuming device and control method therefor

Info

Publication number: WO2020094030A1
Application number: PCT/CN2019/115874
Authority: WO
Inventors: 詹长江; 姜田贵; 谢晔源; 李钢
Original assignee: 南京南瑞继保电气有限公司; 南京南瑞继保工程技术有限公司
Priority date: 2018-11-07
Filing date: 2019-11-06
Publication date: 2020-05-14
Also published as: CN109586327A; CN109586327B

Abstract

Provided by the present application are an energy-consuming device and a control method therefor. The energy-consuming device is connected between a high-potential electrode and a low-potential electrode of a DC line, wherein the energy-consuming device comprises N sub-modules connected in series, N being an integer greater than 1; the sub-module comprises an energy storage circuit, an energy-consuming circuit and a bypass switch, and the energy storage circuit comprises an energy storage capacitor and a first power device which are connected in series; the energy-consuming circuit is connected in parallel to the energy storage circuit, and the energy-consuming circuit comprises a second power device and an energy-consuming resistor which are connected in series; and the bypass switch is connected in parallel to the energy-consuming circuit and the energy storage circuit.

Description

Energy consumption device and its control method

Technical field

This application relates to the technical fields of high-voltage direct current transmission, new energy grid connection, and motor drive. It specifically relates to an energy consumption device and its control method, which can quickly convert the surplus active power on the DC pole line into heat dissipation, and then achieve failure Cross.

Background technique

The use of renewable energy sources such as wind energy and solar energy continues to expand, but its inherent decentralization and distance from load centers make it an urgent and challenging task to study how to connect new wind and other energy sources to the grid. Because wind farms are usually far away from the power grid, large capacitance currents will be generated when connected to the power grid through AC, and high-voltage DC transmission technology has become a feasible and economical solution. Because high-voltage flexible DC transmission technology (VSC-HVDC) can flexibly control active power and reactive power, the reverse DC voltage polarity of power remains unchanged, and it can provide AC voltage support for wind farms. It is considered that it is a new energy source such as wind power. One of the best choices for web.

New energy and other fields that use flexible DC technology to connect to the grid need to face the DC overvoltage problem caused by the active surplus of the DC pole line. The most rapid and reliable way to solve this problem is to set the energy dissipation resistor between the DC pole lines. The DC chopping technology is used to convert the surplus active power into heat through the energy dissipation resistor to achieve the stability of the DC pole line voltage, so that the system will not be disconnected when the fault occurs, and the purpose of fault ride through is achieved.

At present, the commonly used technical solution is the IGBT straight series concentrated resistance solution (as shown in FIG. 1). When this solution works, all power devices are turned on at the same time, and there are problems of series power device voltage equalization and excessive voltage and current change rate. In addition, there is a modular multi-level centralized resistance solution (as shown in Figure 2), which requires the installation of a separate modular multi-level bridge arm valve tower and a separate centralized resistance tower, increasing the overall system Cost and floor space.

Summary of the invention

An embodiment of the present application provides an energy consumption device connected between a high potential electrode and a low potential electrode of a DC line, wherein the energy consumption device includes N sub-modules connected in series, and N is an integer greater than 1 The submodule includes an energy storage circuit, an energy consumption circuit, and a bypass switch. The energy storage circuit includes an energy storage capacitor and a first power device connected in series; the energy consumption circuit is connected in parallel with the energy storage circuit, The energy consuming circuit includes a second power device and an energy consuming resistor connected in series; the bypass switch is connected in parallel with the energy consuming circuit and the energy storage circuit.

According to some embodiments, the energy consuming device further includes a first diode, the first diode is connected in parallel with the energy consuming resistor.

According to some embodiments, the energy consuming device further includes a second diode that is anti-parallel to the second power device.

According to some embodiments, the energy consuming device further includes a third diode that is anti-parallel to the first power device.

According to some embodiments, the first power device and the second power device include at least one of an insulated gate bipolar transistor, a gate turn-off thyristor, an integrated gate commutation thyristor, and a MOS field effect transistor.

An embodiment of the present application also provides a control method for the energy consumption device as described above, including: detecting the DC pole voltage of the DC line in real time; when the DC pole voltage is less than or equal to the upper limit Umax, controlling the The energy consumption device performs standby mode control; when the DC pole voltage is greater than the upper limit Umax, the energy consumption device is controlled to perform energy consumption mode control.

According to some embodiments, the controlling the energy consuming device to perform standby mode control includes: dynamically controlling the single sub-module by controlling the on and off of the first power device and the second power device The voltage of the energy storage capacitor makes the voltage of the energy storage capacitor of all the sub-modules within an allowable range.

According to some embodiments, the controlling the energy consumption device to perform energy consumption mode control includes: when the DC pole voltage is greater than a lower limit value Umin, repeatedly performing the following steps: according to the storage in the submodule The voltage of the capacitor can be turned on from high to low, and the first power device and the second power device of the corresponding sub-module are turned on in turn, and the turn-on time interval is t; the first power device of all the sub-modules, After the second power devices are all turned on, the duration is T1; according to the voltage of the energy storage capacitor in the sub-module, the first power device, the The second power device until all of the first power device and the second power device are turned off, and the off-state time length T2 is maintained; when the DC pole voltage is less than or equal to the lower limit Umin, the The energy consumption device enters the standby mode control.

According to the technical solution provided by the embodiments of the present application, each sub-module contains a capacitor with the functions of energy storage and voltage clamping, and the discharge of the capacitor is controlled by turning on and off the first power device, which perfectly solves the voltage equalization of the power switching device Problems, and can dynamically adjust the capacitor voltage in normal standby state; during energy-consuming operation, the energy-consuming resistors of the submodules are turned on / off in sequence according to the size of the capacitor voltage, until all the energy-consuming resistors are turned on / off, solving the existing solution The problem of excessive current change rate (di / dt) and voltage change rate (du / dt); a distributed resistance solution with integrated energy dissipation resistors for each sub-module, requiring only one valve tower, with a small footprint and cost Low advantage; the topology of each sub-module is exactly the same. By configuring a certain number of sub-modules redundantly, when an individual sub-module fails, it can be bypassed quickly by the bypass switch without affecting its normal operation. The system Strong redundancy operation ability.

BRIEF DESCRIPTION

In order to more clearly explain the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without paying any creative work, other drawings can be obtained based on these drawings.

1 is a schematic diagram of the structure of an energy consumption device in the prior art;

2 is a schematic diagram of another energy consumption device in the prior art;

3 is a schematic diagram of an energy consumption device according to an embodiment of the present application;

4 is a schematic diagram of the structure of a submodule according to an embodiment of the present application;

FIG. 5 is a schematic diagram of the structure of a submodule according to another embodiment of the present application;

6 is a schematic diagram of a logic ladder of energy dissipation resistor input / removal according to an embodiment of the present application;

7 is a schematic flowchart of a control method of an energy consumption device according to an embodiment of the present application;

DESCRIPTION OF REFERENCE NUMERALS: 1. Energy consumption device; 2. Submodule; 3. Energy storage capacitor; 4. First power device; 5. Energy consumption resistance; 6. Third diode; 7. Energy consumption circuit; 8 1. Bypass switch; 9. Second power device; 10. First diode; 11. Second diode.

detailed description

To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following describes the specific implementation manners of the technical solutions of the present application in more detail and clearly with reference to the accompanying drawings and embodiments. However, the specific embodiments and examples described below are for illustrative purposes only, and are not intended to limit the present application. It only includes a part of the embodiments of the present application, but not all the embodiments. Those skilled in the art may obtain other embodiments obtained by various changes of the present application, which all fall within the protection scope of the present application.

In the description of this application, it should be understood that the terms "first", "second", and "third" are for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating what is indicated The number of technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the features.

The present application proposes an energy consumption device with low voltage and current change rate, easy device voltage equalization, low system cost and small footprint.

FIG. 3 is a schematic diagram of an energy consumption device according to an embodiment of the present application.

As shown in FIG. 3, the energy consuming device 1 is connected between the high potential electrode and the low potential electrode of the DC line, and is used to convert the surplus active power on the DC line into thermal energy dissipation, thereby preventing the accumulation of active power on the DC line. The rising of the DC pole line voltage jeopardizes the operation safety of the system. The energy consumption device 1 includes N sub-modules 2 connected in series, and N is an integer greater than 1.

FIG. 4 is a schematic diagram of a submodule according to an embodiment of the present application.

As shown in FIG. 4, the submodule 2 includes an energy storage circuit, an energy consumption circuit 7 and a bypass switch 8.

The energy storage circuit includes an energy storage capacitor 3 and a first power device 4 connected in series. The energy consumption circuit 7 is connected in parallel with the energy storage circuit. The energy dissipation circuit 7 includes a second power device 9 and an energy dissipation resistor 5 connected in series. The bypass switch 8 is connected in parallel with the energy consumption circuit 7 and the energy storage circuit.

The first power device 4 and the second power device 9 include at least one of an insulated gate bipolar transistor, a gate turn-off thyristor, an integrated gate commutation thyristor, and a MOS field effect transistor.

The discharge of the energy storage capacitor 3 is controlled by controlling the on and off of the first power device 4 to provide a clamping voltage for the first power device 4 and the second power device 9 of the sub-module 2 to solve the voltage equalization problem of the power device. The rate of change of voltage and current during the input process of the energy-consuming resistor 5 is reduced to reduce the impact on the system.

In order not to affect the normal operation of the system when the submodule 2 fails, a bypass switch 8 is connected in parallel between the two output terminals of the submodule 2 to trigger the bypass switch 8 when a submodule 2 fails The module is bypassed.

FIG. 5 is a schematic diagram of a submodule according to an embodiment of the present application.

As shown in FIG. 5, the submodule 2 includes an energy storage circuit, an energy consumption circuit 7, and a bypass switch 8.

Optionally, the energy consuming device 1 further includes a first diode 10 which is connected in parallel with the energy consuming resistor 5. When current flows through the energy dissipation resistor 5 and the second power device 9 is turned off, the parallel first diode 10 can provide continuous flow for the inductive current on the energy dissipation resistor 5 due to the stray inductance of the energy dissipation resistor 5 Road.

Optionally, the energy consumption device 1 further includes a second diode 11, and the second diode 11 is anti-parallel to the second power device 9. The second diode 11 connected in parallel can provide a free-wheeling channel for the second power device 9.

Optionally, the energy consuming device 1 further includes a third diode 6 which is anti-parallel to the first power device 4. The third diode 6 connected in parallel can provide a freewheeling channel for the first power device 4.

FIG. 7 is a schematic flowchart of a control method of an energy consuming device according to an embodiment of the present application, showing the control flow of the energy consuming device.

As shown in Figure 7, Step 1: Detect the DC pole voltage of the DC line in real time.

As shown in FIG. 7, Step 2: When the DC pole voltage is less than or equal to the upper limit Umax, the energy consumption device is controlled to perform standby mode control.

By controlling the turn-on and turn-off of the first power device and the second power device, the voltage of the energy storage capacitors in a single sub-module is dynamically adjusted so that the voltages of the energy storage capacitors of all sub-modules are within the allowable range.

As shown in FIG. 7, step 3: when the DC pole voltage is greater than the upper limit Umax, the energy consumption device is controlled to perform energy consumption mode control.

When the DC pole voltage is greater than the lower limit Umin, repeat the following

steps

31, 32, 33.

Step 31: According to the voltage of the energy storage capacitor in the sub-module from high to low, turn on the first power device and the second power device of the corresponding sub-module in turn, and the turn-on time interval is t, as shown in FIG. 6 and FIG. 6 It is a schematic diagram of an energy dissipation resistor input / cut logic ladder according to an embodiment of the present application. In the figure, R is the DC capacitor voltage of each sub-module.

Step 32: After the first power device and the second power device of all sub-modules are turned on, the duration is T1.

Step 33: Turn off the first power device and the second power device of the corresponding sub-module in turn according to the voltage of the energy storage capacitor in the sub-module from low to high until all the first power device and the second power device are turned off to maintain The length of the off state is T2.

Step 34: When the DC pole voltage is less than or equal to the lower limit Umin, control the energy consuming device to enter the standby mode control.

In summary, the technical solution of the present application can also be fully applied to other application fields of medium and high DC transmission.

It should be noted that the embodiments described above with reference to the drawings are only used to illustrate the present application and not to limit the scope of the present application. Those of ordinary skill in the art should understand that without departing from the spirit and scope of the present application Modifications or equivalent replacements made to this application should be covered within the scope of this application. In addition, unless the context indicates otherwise, words in the singular include the plural and vice versa. In addition, unless specifically stated otherwise, all or part of any embodiment may be used in combination with all or part of any other embodiment.

Claims

An energy consuming device connected between a high potential electrode and a low potential electrode of a DC line, wherein the energy consuming device includes:

N sub-modules connected in series, N is an integer greater than 1; the sub-modules include:

An energy storage circuit, including an energy storage capacitor and a first power device connected in series;

An energy dissipation circuit is connected in parallel with the energy storage circuit, and the energy dissipation circuit includes a second power device and an energy dissipation resistor connected in series;

The bypass switch is connected in parallel with the energy consuming circuit and the energy storage circuit.
The energy consuming device of claim 1, further comprising:

The first diode is connected in parallel with the energy dissipation resistor.
The energy consuming device of claim 1, further comprising:

The second diode is connected in anti-parallel to the second power device.
The energy consuming device of claim 1, further comprising:

The third diode is connected in anti-parallel to the first power device.
The energy consuming device according to any one of claims 1 to 4, wherein the first power device and the second power device include an insulated gate bipolar transistor, a gate turn-off thyristor, and an integrated gate At least one of a converter thyristor and a MOS field effect transistor.
A control method of an energy consuming device according to claims 1 to 5, comprising:

Real-time detection of the DC pole line voltage of the DC line;

When the DC pole line voltage is less than or equal to the upper limit Umax, the energy consuming device is controlled to perform standby mode control;

When the DC pole line voltage is greater than the upper limit Umax, the energy consumption device is controlled to perform energy consumption mode control.
The control method according to claim 6, wherein the controlling the energy consuming device to perform standby mode control includes:

By controlling the turn-on and turn-off of the first power device and the second power device, the voltage of the energy storage capacitor in a single sub-module is dynamically adjusted so that the energy storage capacitors of all the sub-modules Is within the allowable range.
The control method according to claim 6, wherein the controlling the energy consuming device to perform energy consumption mode control includes:

When the DC pole voltage is greater than the lower limit Umin, repeat the following steps:

According to the voltage of the energy storage capacitor in the submodule from high to low, turn on the first power device and the second power device of the corresponding submodule in turn, and the turn-on time interval is t;

After the first power device and the second power device of all the submodules are turned on, the duration is T1;

According to the voltage of the energy storage capacitor in the submodule from low to high, turn off the first power device and the second power device of the corresponding submodule in turn, until all the first power devices, the The second power devices are all turned off, and the time length T2 of maintaining the off state is maintained;

When the DC pole voltage is less than or equal to the lower limit Umin, the energy consuming device is controlled to enter the standby mode control.