Shock-free charging method and apparatus for supercapacitor in a grid-forming static synchronous compensator

Abstract

Provided is a shock-free charging method and apparatus for a supercapacitor in a grid-forming static synchronous compensator. The shock-free charging method comprises: on the basis of a DC-side reference voltage of a modular multilevel converter in a grid-forming static synchronous compensator, controlling a DC-side actual voltage of the modular multilevel converter valve; on the basis of a preset first rising slope, controlling the DC-side actual voltage to rise to a preset first voltage threshold, and performing uncontrolled rectification charging on a supercapacitor converter valve in the grid-forming static synchronous compensator; and on the basis of a preset second rising slope, controlling the DC-side actual voltage to rise to a preset second voltage threshold, and performing shock-free charging on the supercapacitor converter valve on the basis of a preset duty cycle, wherein the preset second voltage threshold is greater than the preset first voltage threshold.

Description

Non-impact charging method and device for super capacitor in grid-connected static synchronous compensator

[0001] The present disclosure claims priority to Chinese Patent Application No. 202510137237.2, filed on February 7, 2025, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of flexible power transmission, in particular to a non-impact charging method and device for a super capacitor in a grid-connected static synchronous compensator. BACKGROUND

[0003] With the increasing acceleration of power system construction, new energy has gradually become the main body of new installed capacity and new power generation. With the continuous improvement of new energy penetration rate, the power system is gradually showing a high power electronic trend, and the operation mechanism and safety and stability characteristics of the previous synchronous machine-based power system are undergoing profound changes.

[0004] In order to improve the reactive voltage control capability of the power system including new energy (which can be referred to as a new type of power system), a grid-connected static synchronous compensator (STATCOM) is usually arranged in a new energy station and an AC collection station. STATCOM is a reactive power compensation device, and its main function is to provide or absorb reactive power to improve the power factor of the new type of power system and maintain the voltage stability of the new type of power system. SUMMARY

[0005] In one aspect, the present disclosure provides a non-impact charging method for a super capacitor in a grid-connected static synchronous compensator, the non-impact charging method comprising:

[0006] controlling a direct-current side actual voltage of the modular multilevel converter according to a direct-current side reference voltage of the modular multilevel converter.

[0007] controlling the direct-current side actual voltage to rise to a preset first voltage threshold according to a preset first rising slope, and performing non-controlled rectification charging on the super capacitor converter in the grid-connected static synchronous compensator.

[0008] controlling the direct-current side actual voltage to rise to a preset second voltage threshold according to a preset second rising slope, and performing non-impact charging on the super capacitor converter according to a preset duty ratio.

[0009] wherein the preset second voltage threshold is greater than the preset first voltage threshold.

[0010] In some implementations, the DC side actual voltage of the modular multilevel converter is controlled according to the DC side reference voltage of the modular multilevel converter in the grid-connected static synchronous compensator, comprising:

[0011] According to the DC side reference voltage, the DC side actual voltage is proportionally integrated controlled to be 0.

[0012] In other implementations, the DC side actual voltage is controlled to rise to a preset first voltage threshold according to a preset first rising slope, and the super capacitor converter in the grid-connected static synchronous compensator is controlled to be charged by uncontrolled rectification, comprising:

[0013] All sub-modules in the super capacitor converter are turned off, and the DC switch between the modular multilevel converter and the super capacitor converter is closed.

[0014] The DC side actual voltage is gradually raised according to the preset first rising slope, and the super capacitor in the sub-module is charged by uncontrolled rectification through the antiparallel diode of the power device in the sub-module.

[0015] In the case that the DC side actual voltage rises to the preset first voltage threshold, all sub-modules are powered on for self-checking, and if any sub-module fails, all sub-modules stop uncontrolled rectification charging and are repaired.

[0016] Exemplarily, the preset first voltage threshold satisfies: dcset1 = N·U dc_start ;

[0017] Wherein, U dcset1 represents the preset first voltage threshold, N represents the number of sub-modules in the super capacitor converter, and U dc_start represents the starting voltage of the driving module for sending driving signals to the sub-modules.

[0018] In yet other implementations, the DC side actual voltage is controlled to rise to a preset second voltage threshold according to a preset second rising slope, and the super capacitor converter is charged by non-impact charging according to a preset duty ratio, comprising:

[0019] The DC side actual voltage is gradually raised according to the preset second rising slope, and the super capacitor converter is charged by non-impact charging according to the preset duty ratio.

[0020] The DC voltages of all turned-off sub-modules and all bypassed sub-modules are collected, and the maximum DC voltage of the turned-off sub-module and the minimum DC voltage of the bypassed sub-module are selected.

[0021] When the voltage difference between the maximum DC voltage of the shutdown submodule and the minimum DC voltage of the bypassed submodule is greater than a preset third voltage threshold, the submodule corresponding to the minimum DC voltage of the bypassed submodule is shut down, and the submodule corresponding to the maximum DC voltage of the shutdown submodule is bypassed.

[0022] If the DC voltage on the DC side rises to a preset second voltage threshold, and the DC voltage of the submodule is within a preset voltage range, then the supercapacitor converter valve completes shockless charging. Otherwise, shockless charging of the supercapacitor converter valve continues according to a preset duty cycle until the DC voltage of the submodule is within the preset voltage range.

[0023] In some embodiments, the preset second voltage threshold satisfies: U dcset2 =(N-1)U scn ;

[0024] Among them, U dcset2 This represents the preset second voltage threshold, N represents the number of sub-modules in the supercapacitor converter valve, and U... scn This indicates the rated voltage of the submodule.

[0025] For example, the preset duty cycle satisfies:

[0026] Where D represents the preset duty cycle and N represents the number of sub-modules in the supercapacitor converter valve.

[0027] Furthermore, the shock-free charging method provided in this disclosure also includes:

[0028] By shutting down all submodules in the supercapacitor converter valve, the actual DC-side voltage is controlled to drop to the rated DC-side voltage of the modular multilevel converter valve.

[0029] On the other hand, this disclosure also provides a shockless charging device for a supercapacitor in a grid-type static synchronous condenser, and the shockless charging device includes: a control module, a first charging module, and a second charging module.

[0030] The control module is used to control the actual DC side voltage of the modular multilevel converter valve based on the DC side reference voltage of the modular multilevel converter valve in the grid-type static synchronous condenser.

[0031] The first charging module is used to control the actual DC side voltage to rise to a preset first voltage threshold according to a preset first rising slope, and to perform uncontrolled rectified charging on the supercapacitor converter valve in the grid-type static synchronous condenser.

[0032] The second charging module is used to control the actual DC side voltage to rise to a preset second voltage threshold according to a preset second rising slope, and to perform shockless charging of the supercapacitor converter valve according to a preset duty cycle.

[0033] The preset second voltage threshold is greater than the preset first voltage threshold.

[0034] In one implementation, the control module is used to:

[0035] Based on the DC-side reference voltage, proportional-integral control is applied to the actual DC-side voltage to make the actual DC-side voltage zero.

[0036] In another implementation, the first charging module is used for:

[0037] Shut down all submodules in the supercapacitor converter valve and close the DC switch between the modular multilevel converter valve and the supercapacitor converter valve.

[0038] The actual DC voltage gradually increases according to the preset first rising slope, and the supercapacitor in the submodule is charged by uncontrolled rectification through the anti-parallel diode of the power device in the submodule.

[0039] When the actual DC voltage rises to the preset first voltage threshold, all submodules power on and perform self-tests. If any submodule fails, all submodules stop uncontrolled rectifier charging and are then inspected.

[0040] For example, the preset first voltage threshold satisfies: U dcset1 =N·U dc_start ;

[0041] Among them, U dcset1 U represents the preset first voltage threshold, N represents the number of sub-modules in the supercapacitor converter valve, and U represents the number of sub-modules in the supercapacitor converter valve. dc_start This indicates the startup voltage of the drive module used to send drive signals to the submodule.

[0042] In another implementation, the second charging module is used for:

[0043] The DC side voltage gradually increases according to the preset second rising slope, and the supercapacitor converter valve is charged without impact according to the preset duty cycle.

[0044] Collect the DC voltage of each of the shutdown submodules and the bypassed submodules, and select the maximum DC voltage of the shutdown submodule and the minimum DC voltage of the bypassed submodule.

[0045] When the voltage difference between the maximum DC voltage of the shutdown submodule and the minimum DC voltage of the bypassed submodule is greater than a preset third voltage threshold, the submodule corresponding to the minimum DC voltage of the bypassed submodule is shut down, and the submodule corresponding to the maximum DC voltage of the shutdown submodule is bypassed.

[0046] If the DC voltage on the DC side rises to a preset second voltage threshold, and the DC voltage of the submodule is within a preset voltage range, then the supercapacitor converter valve completes shockless charging. Otherwise, shockless charging of the supercapacitor converter valve continues according to a preset duty cycle until the DC voltage of the submodule is within the preset voltage range.

[0047] In some embodiments, the preset second voltage threshold satisfies: U dcset2 =(N-1)U scn ;

[0048] Among them, U dcset2 This represents the preset second voltage threshold, N represents the number of sub-modules in the supercapacitor converter valve, and U... scn This indicates the rated voltage of the submodule.

[0049] For example, the preset duty cycle satisfies:

[0050] Where D represents the preset duty cycle and N represents the number of sub-modules in the supercapacitor converter valve.

[0051] Furthermore, the control module is also used for:

[0052] By shutting down all submodules in the supercapacitor converter valve, the actual DC-side voltage is controlled to drop to the rated DC-side voltage of the modular multilevel converter valve.

[0053] In another aspect, embodiments of this disclosure also provide a computer device, and the computer device includes: one or more processors;

[0054] One or more processors are used to execute one or more programs;

[0055] When one or more programs are executed by one or more processors, the shockless charging method described above is implemented.

[0056] In another aspect, embodiments of this disclosure also provide a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the shockless charging method as described above. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 is a schematic structural diagram of a grid-type stationary synchronous condenser according to some embodiments.

[0059] Figure 2 is a schematic structural diagram of a submodule according to some embodiments.

[0060] Figure 3 is another schematic structural diagram of a submodule according to some embodiments.

[0061] Figure 4 is a schematic flowchart of a shockless charging method for a supercapacitor according to some embodiments.

[0062] Figure 5 is a schematic structural diagram of a shockless charging device for a supercapacitor according to some embodiments. Detailed Implementation

[0063] The technical solutions in this disclosure will now be described with reference to the accompanying drawings.

[0064] The terms "first," "second," etc., used in the embodiments, claims, and drawings of this disclosure are for distinguishing purposes only and should not be construed as indicating or implying relative importance or order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or apparatus is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0065] It should be understood that in this disclosure, "at least one item" means one or more, and "more than one" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0066] With the accelerating pace of power system construction, new energy sources are gradually becoming the main contributors to new installed capacity and power generation. As the penetration rate of new energy sources continues to increase, the power system is gradually showing a trend towards high levels of power electronics, and the operating mechanism and safety and stability characteristics of the power system, which was previously based on synchronous machines, are undergoing profound changes.

[0067] To enhance the reactive power and voltage control capabilities of power systems including renewable energy sources (referred to as new power systems), grid-type static synchronous condensers (STATCOMs) are typically installed at renewable energy power plants and AC substations. A STATCOM is a reactive power compensation device whose main function is to provide or absorb reactive power to improve the power factor and maintain voltage stability of the new power system.

[0068] The voltage and inertia support devices provided by related technologies may include a Modular Multilevel Converter (MMC) and an energy storage converter valve. The AC side of the MMC is connected to the AC power grid, and the DC side of the MMC is connected to the energy storage converter valve. The energy storage converter valve includes multiple sub-modules, each of which may include a battery and a soft-start resistor. Because of energy losses in the soft-start resistor, the charging efficiency of the energy storage converter valve is low, which in turn leads to low startup efficiency of the voltage and inertia support devices.

[0069] In view of this, the present disclosure provides a method for shockless charging of supercapacitors in a grid-type static synchronous condenser, comprising: controlling the actual DC-side voltage of the modular multilevel converter valve according to the DC-side reference voltage of the modular multilevel converter valve in the grid-type static synchronous condenser; controlling the actual DC-side voltage to rise to a preset first voltage threshold according to a preset first rising slope, and performing uncontrolled rectified charging on the supercapacitor converter valve in the grid-type static synchronous condenser; controlling the actual DC-side voltage to rise to a preset second voltage threshold according to a preset second rising slope, and performing shockless charging on the supercapacitor converter valve according to a preset duty cycle; wherein the preset second voltage threshold is greater than the preset first voltage threshold.

[0070] Example 1:

[0071] This disclosure provides a shockless charging method for supercapacitors in a grid-type static synchronous condenser (STATCOM). As shown in Figure 1, the grid-type STATCOM may include a modular multilevel converter valve 1 and a supercapacitor converter valve 2. The AC side of the modular multilevel converter valve 1 can be connected to the AC power grid G ​​via an AC switch QFac, and the DC side of the modular multilevel converter valve 1 can be connected to the supercapacitor converter valve 2 via DC switches QF1dc and QF2dc. The supercapacitor converter valve 2 may include multiple sub-modules connected in series. The multiple sub-modules connected in series include N sub-modules in Figure 1: sub-module SC-SM1, sub-module SC-SM2, ..., sub-module SC-SMN-1, and sub-module SC-SMN.

[0072] The modular multilevel converter valve 1 includes an A-phase bridge arm, a B-phase bridge arm, and a C-phase bridge arm. Each phase bridge arm includes an upper bridge arm and a lower bridge arm, and both the upper and lower bridge arms include multiple sub-modules connected in series. For example, the A-phase bridge arm includes sub-modules SMa1 to SMa2N, the B-phase bridge arm includes sub-modules SMb1 to SMb2N, and the C-phase bridge arm includes sub-modules SMc1 to SMc2N. In Figure 1, L represents the bridge arm reactance. U dc This represents the actual DC-side voltage of the modular multilevel converter valve 1.

[0073] As shown in Figure 2, each submodule can be a half-bridge structure, including power device T1, power device T2, and supercapacitor SC. Both power devices T1 and T2 can be insulated-gate bipolar transistors (IGBTs), with diodes connected in anti-parallel to the IGBTs. The first terminal of power device T1 is connected to the first terminal of supercapacitor SC, and the second terminal of power device T1 is connected to the first terminal of power device T2, serving as the first terminal of the submodule. The second terminal of power device T2 is connected to the second terminal of supercapacitor SC, serving as the second terminal of the submodule.

[0074] As shown in Figure 3, each submodule can be a full-bridge structure, including power devices T1, T2, T3, T4, and a supercapacitor SC. Power devices T1, T2, T3, and T4 can all be insulated-gate bipolar transistors (IGBTs), and each IGBT is connected in anti-parallel to a diode.

[0075] As shown in Figure 4, the shockless charging method 100 provided in this embodiment includes: S1 to S3.

[0076] S1: Based on the DC side reference voltage of modular multilevel converter valve 1 in the grid-type static synchronous condenser (which can be U...ref (Indicates) the actual DC side voltage U of the control modular multilevel converter valve 1 dc .

[0077] S2: Control the actual DC side voltage U according to the preset first rising slope (which can be represented by k1). dc Increase to a preset first voltage threshold (which can be achieved using U) dcset1 (This is indicated), and uncontrolled rectification charging is performed on the supercapacitor converter valve 2 in the grid-type static synchronous condenser.

[0078] S3: Control the actual DC side voltage U according to the preset second rising slope (which can be represented by k2). dc Increase to a preset second voltage threshold (which can be achieved using U) dcset2 (represented by D), and perform shockless charging on the supercapacitor converter valve 2 according to the preset duty cycle (which can be represented by D).

[0079] Preset second voltage threshold U dcset2 Greater than the preset first voltage threshold U dcset1 The first and second ascent slopes may be the same or different, and this disclosure does not limit this.

[0080] In some embodiments, S1 is based on the DC-side reference voltage U of the modular multilevel converter valve 1. ref Controlling the actual DC side voltage U of the modular multilevel converter valve dc ,include:

[0081] According to the DC side reference voltage U ref For the actual DC side voltage U dc Perform proportional-integral control (i.e., PI control) to make the actual DC side voltage U... dc It is 0.

[0082] In other embodiments, in S2, the actual DC-side voltage U is controlled according to a preset first rising slope k1. dc Rise to the preset first voltage threshold U dcset1 And perform uncontrolled rectified charging on the supercapacitor converter valve 2, including:

[0083] Shut down all submodules in the supercapacitor converter valve 2, and close the DC switches QF1dc and QF2dc between the modular multilevel converter valve 1 and the supercapacitor converter valve 2.

[0084] The actual DC-side voltage U is controlled according to the preset first rising slope k1. dc As the voltage gradually increases, the supercapacitor SC in the submodule undergoes uncontrolled rectified charging through the anti-parallel diodes of the power devices in the submodule.

[0085] The actual voltage U on the DC side dc Rise to the preset first voltage threshold U dcset1 In this case, all submodules undergo electrical self-test. If any submodule fails, all submodules stop uncontrolled rectifier charging and are then repaired.

[0086] For example, a preset first voltage threshold U dcset1 Satisfy: U dcset1 =N·U dc_start ;

[0087] U dcset1 This represents the preset first voltage threshold, N represents the number of submodules in the supercapacitor converter valve 2, and U... dc_start This indicates the startup voltage of the drive module used to send drive signals to the submodule. In some embodiments, the drive module typically uses DC power.

[0088] In some other embodiments, in S3, the actual DC-side voltage U is controlled according to a preset second rising slope k2. dc Increase to the preset second voltage threshold U dcset2 And perform shockless charging of the supercapacitor converter valve 2 according to the preset duty cycle D, including:

[0089] The actual DC-side voltage U is controlled according to the preset second rising slope k2. dc The voltage gradually increases, and the supercapacitor converter valve 1 is charged without impact according to the preset duty cycle D.

[0090] Collect the DC voltage of each of the shutdown submodules and all bypassed submodules (which can be bypassed by turning on the power device T2 in Figure 3), and select the maximum DC voltage of the shutdown submodule (which can be represented by U). sc_max (represented) and the minimum DC voltage of the bypassed submodule (which can be represented by U) sc_min express).

[0091] When the maximum DC voltage U of the shutdown submodule is sc_max (The corresponding submodule can be denoted as submodule SC-SM) j The minimum DC voltage U of the bypassed submodule sc_min (The corresponding submodule can be denoted as submodule SC-SM) k The voltage difference between them (which can be expressed as ΔU) sc If the voltage value (indicated by) is greater than the preset third voltage threshold (e.g., 20V), then the minimum DC voltage U of the bypassed submodule will be shut off. sc_min The corresponding submodule (i.e., the shutdown submodule SC-SM) k And bypass the maximum DC voltage U of the shutdown submodule. sc_maxThe corresponding submodule (i.e., the bypass submodule SC-SM) j ).

[0092] The actual voltage U on the DC side dc Increase to the preset second voltage threshold U dcset2 In this case, if the DC voltage of the submodule is within the preset voltage range (the preset voltage range can be 0.95U), scn ~1.05U scn U scn If the voltage of the submodule is within the rated voltage range (indicating the submodule's rated voltage), then the supercapacitor converter valve 2 completes shockless charging. Otherwise, the supercapacitor converter valve 2 continues to be charged shocklessly according to the preset duty cycle D until the DC voltage of the submodule is within the preset voltage range.

[0093] In some embodiments, the preset second voltage threshold satisfies: U dcset2 =(N-1)U scn ;

[0094] U dcset2 This indicates the preset second voltage threshold, N represents the number of submodules in the supercapacitor converter valve 2, and U... scn This indicates the rated voltage of the submodule.

[0095] For example, the preset duty cycle satisfies:

[0096] D represents the preset duty cycle, and N represents the number of sub-modules in the supercapacitor converter valve.

[0097] Furthermore, the shockless charging method 100 provided in this embodiment of the present disclosure also includes:

[0098] By shutting down all submodules in the supercapacitor converter valve 2, the actual DC-side voltage U is controlled via the modular multilevel converter valve 1. dc The voltage drops to the DC-side rated voltage of the modular multilevel converter valve 1.

[0099] In summary, the charging method provided in this disclosure does not involve the addition or alteration of hardware and has strong engineering applicability.

[0100] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0101] The shockless charging method for supercapacitors in a grid-type static synchronizing phase (SSR) provided in this disclosure controls the actual DC-side voltage of the modular multilevel converter valve based on the DC-side reference voltage of the modular multilevel converter valve in the SSR. The actual DC-side voltage is raised to a preset first voltage threshold according to a preset first rising slope, and uncontrolled rectified charging is performed on the supercapacitor converter valve in the SSR. The actual DC-side voltage is raised to a preset second voltage threshold according to a preset second rising slope, and shockless charging is performed on the supercapacitor converter valve according to a preset duty cycle. It can be seen that this disclosure improves the charging efficiency of the supercapacitor converter valve by controlling the actual DC-side voltage to charge the supercapacitor converter valve in different ways, thereby improving the start-up efficiency of the grid-type SSR.

[0102] When the actual DC voltage is 0 in this disclosure, closing the DC switch between the modular multilevel converter valve and the supercapacitor converter valve will not cause any voltage or current surges to the supercapacitor converter valve or the AC system connected to the modular multilevel converter valve. In other words, it will not affect the normal operation of the AC system, nor will it affect the subsequent uncontrolled rectification charging and surge-free charging of the supercapacitor converter valve.

[0103] This disclosure enables the control of DC voltage balance among submodules when the voltage difference between the maximum DC voltage of the shutdown submodule and the minimum DC voltage of the bypassed submodule exceeds a preset third voltage threshold. In this case, the submodule corresponding to the minimum DC voltage of the bypassed submodule is shut down, and the submodule corresponding to the maximum DC voltage of the shutdown submodule is bypassed. This ensures no impact on the AC system during the entire charging process of the supercapacitor converter valve, thus achieving impact-free charging of the supercapacitor converter valve.

[0104] The supercapacitor converter valve of the grid-type static synchronous condenser disclosed herein does not require a separate slow-start resistor, thus avoiding the power loss of the slow-start resistor and further improving the start-up efficiency of the grid-type static synchronous condenser.

[0105] Example 2:

[0106] Based on the same inventive concept, this disclosure also provides a shockless charging device for supercapacitors in a grid-type static synchronous condenser. For a detailed description of the grid-type static synchronous condenser, please refer to the above text and related drawings; this disclosure will not repeat this embodiment.

[0107] As shown in Figure 5, the impact-free charging device 200 includes: a control module 21, a first charging module 22, and a second charging module 23.

[0108] Control module 21 is used to determine the DC side reference voltage U of modular multilevel converter valve 1. refControlling the actual DC side voltage U of the modular multilevel converter valve 1 dc .

[0109] The first charging module 22 is used to control the actual DC-side voltage U according to a preset first rising slope k1. dc Rise to the preset first voltage threshold U dcset1 Uncontrolled rectification charging is performed on the supercapacitor converter valve 2 in the grid-type static synchronous condenser.

[0110] The second charging module 23 is used to control the actual DC-side voltage U according to the preset second rising slope k2. dc Increase to the preset second voltage threshold U dcset2 And charge the supercapacitor converter valve 2 without impact according to the preset duty cycle D.

[0111] Preset second voltage threshold U dcset2 Greater than the preset first voltage threshold U dcset1 The first and second ascent slopes may be the same or different, and this disclosure does not limit this.

[0112] In some embodiments, the control module 21 is used for:

[0113] According to the DC side reference voltage U ref For the actual DC side voltage U dc Perform proportional-integral control to make the actual DC side voltage U dc It is 0.

[0114] In other embodiments, the first charging module 22 is used for:

[0115] Shut down all submodules in the supercapacitor converter valve 2, and close the DC switches QF1dc and QF2dc between the modular multilevel converter valve 1 and the supercapacitor converter valve 2.

[0116] The actual DC-side voltage U is controlled according to the preset first rising slope k1. dc As the voltage gradually increases, the supercapacitor SC in the submodule undergoes uncontrolled rectified charging through the anti-parallel diodes of the power devices in the submodule.

[0117] The actual voltage U on the DC side dc Rise to the preset first voltage threshold U dcset1 In this case, all submodules undergo electrical self-test. If any submodule fails, all submodules stop uncontrolled rectifier charging and are then repaired.

[0118] For example, a preset first voltage threshold U dcset1 Satisfy: U dcset1 =N·Udc_start ;

[0119] U dcset1 U represents the preset first voltage threshold, N represents the number of sub-modules in the supercapacitor converter valve, and U represents the number of sub-modules in the supercapacitor converter valve. dc_start This indicates the startup voltage of the drive module used to send drive signals to the submodule.

[0120] In yet other embodiments, the second charging module 23 is used for:

[0121] The actual DC-side voltage U is controlled according to the preset second rising slope k2. dc The voltage gradually increases, and the supercapacitor converter valve 1 is charged without impact according to the preset duty cycle D.

[0122] Collect the DC voltage of each of the shutdown submodules and all bypassed submodules (which can be bypassed by turning on the power device T2 in Figure 3), and select the maximum DC voltage of the shutdown submodule (which can be represented by U). sc_max (represented) and the minimum DC voltage of the bypassed submodule (which can be represented by U) sc_min express).

[0123] When the maximum DC voltage U of the shutdown submodule is sc_max (The corresponding submodule can be denoted as submodule SC-SM) j The minimum DC voltage U of the bypassed submodule sc_min (The corresponding submodule can be denoted as submodule SC-SM) k The voltage difference between them (which can be expressed as ΔU) sc If the voltage value (indicated by) is greater than the preset third voltage threshold (e.g., 20V), then the minimum DC voltage U of the bypassed submodule will be shut off. sc_min The corresponding submodule (i.e., the shutdown submodule SC-SM) k And bypass the maximum DC voltage U of the shutdown submodule. sc_max The corresponding submodule (i.e., the bypass submodule SC-SM) j ).

[0124] The actual voltage U on the DC side dc Increase to the preset second voltage threshold U dcset2 In this case, if the DC voltage of the submodule is within a preset voltage range (this preset voltage range can be 0.95U), scn ~1.05U scn U scn If the voltage of the submodule is within the rated voltage range (indicating the submodule's rated voltage), then the supercapacitor converter valve 2 completes shockless charging. Otherwise, the supercapacitor converter valve 2 continues to be charged shocklessly according to the preset duty cycle D until the DC voltage of the submodule is within the preset voltage range.

[0125] In some embodiments, the preset second voltage threshold satisfies: U dcset2 =(N-1)U scn ;

[0126] U dcset2 This indicates the preset second voltage threshold, N represents the number of submodules in the supercapacitor converter valve 2, and U... scn This indicates the rated voltage of the submodule.

[0127] For example, the preset duty cycle satisfies:

[0128] D represents the preset duty cycle, and N represents the number of sub-modules in the supercapacitor converter valve.

[0129] Furthermore, the control module 21 is also used for:

[0130] By shutting down all submodules in the supercapacitor converter valve 2, the actual DC-side voltage U is controlled via the modular multilevel converter valve 1. dc The voltage drops to the DC-side rated voltage of the modular multilevel converter valve 1.

[0131] Example 3:

[0132] Based on the same inventive concept, this disclosure also provides a computer device, which includes a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, and is suitable for implementing one or more instructions, such as loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the shockless charging method provided in the above embodiments.

[0133] Example 4:

[0134] Based on the same inventive concept, this disclosure also provides a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium), such as a computer-readable storage medium (Memory). A computer-readable storage medium is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the shockless charging method provided in the above embodiments.

[0135] Those skilled in the art will understand that the disclosed embodiments can be provided as methods, systems, or computer program products. Therefore, the disclosure may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the disclosure may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0136] The disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to the disclosed embodiments. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart illustrations and / or one or more block diagrams.

[0137] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0138] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0139] The above are merely disclosed embodiments and are not intended to limit the disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the disclosure principles are included within the scope of the disclosed claims of the invention pending approval.

Claims

1. A shockless charging method for supercapacitors in a grid-type static synchronous condenser, comprising: The DC side actual voltage of the modular multilevel converter valve is controlled according to the DC side reference voltage of the modular multilevel converter valve in the grid-type static synchronous condenser. The actual voltage on the DC side is controlled to rise to a preset first voltage threshold according to a preset first rising slope, and the supercapacitor converter valve in the grid-type static synchronous condenser is subjected to uncontrolled rectification charging. The actual DC voltage is controlled to rise to a preset second voltage threshold according to a preset second rising slope, and the supercapacitor converter valve is charged without impact according to a preset duty cycle. Wherein, the preset second voltage threshold is greater than the preset first voltage threshold.

2. The shockless charging method according to claim 1, wherein, The step of controlling the actual DC-side voltage of the modular multilevel converter valve based on the DC-side reference voltage of the modular multilevel converter valve in the grid-type static synchronous condenser includes: Based on the DC-side reference voltage, the DC-side actual voltage is subjected to proportional-integral control to make the DC-side actual voltage 0.

3. The shockless charging method according to claim 1, wherein, The step of controlling the actual DC-side voltage to rise to the preset first voltage threshold according to a preset first rising slope, and performing uncontrolled rectified charging on the supercapacitor converter valve in the grid-type static synchronous condenser, includes: Shut down all sub-modules in the supercapacitor converter valve and close the DC switch between the modular multilevel converter valve and the supercapacitor converter valve; The actual DC voltage is gradually increased according to the preset first rising slope, and the supercapacitor in the submodule is charged by uncontrolled rectification through the anti-parallel diode of the power device in the submodule. When the actual voltage on the DC side rises to the preset first voltage threshold, all submodules undergo an electrical self-test. If any submodule fails, all submodules stop uncontrolled rectifier charging and are then repaired.

4. The shockless charging method according to claim 1, wherein, The preset first voltage threshold satisfies: U dcset1 =N·U dc_start ; Among them, U dcset1 U represents the preset first voltage threshold, N represents the number of submodules in the supercapacitor converter valve, and U represents the number of submodules in the supercapacitor converter valve. dc_start This indicates the startup voltage of the drive module used to send drive signals to the submodule.

5. The shockless charging method according to claim 1, wherein, The step of controlling the actual DC-side voltage to rise to a preset second voltage threshold according to a preset second rising slope, and performing shockless charging of the supercapacitor converter valve according to a preset duty cycle includes: The actual DC voltage is gradually increased according to the preset second rising slope, and the supercapacitor converter valve is charged without impact according to the preset duty cycle. Collect the DC voltage of each of the shut-off submodules and the bypassed submodules, and select the maximum value of the DC voltage of each shut-off submodule and the minimum value of the DC voltage of each bypassed submodule. When the voltage difference between the maximum DC voltage of the shutdown submodule and the minimum DC voltage of the bypassed submodule is greater than a preset third voltage threshold, the submodule corresponding to the minimum DC voltage of the bypassed submodule is shut down, and the submodule corresponding to the maximum DC voltage of the shutdown submodule is bypassed. If the DC voltage on the DC side rises to the preset second voltage threshold, and the DC voltage of the submodule is within the preset voltage range, then the supercapacitor converter valve completes shockless charging; otherwise, the supercapacitor converter valve continues to be charged shocklessly according to the preset duty cycle until the DC voltage of the submodule is within the preset voltage range.

6. The shockless charging method according to claim 1, wherein, The preset second voltage threshold satisfies: U dcset2 =(N-1)U scn ; Among them, U dcset2 U represents the preset second voltage threshold, N represents the number of submodules in the supercapacitor converter valve, and U represents the number of submodules in the supercapacitor converter valve. scn This indicates the rated voltage of the submodule.

7. The shockless charging method according to claim 1, wherein, The preset duty cycle satisfies: Wherein, D represents the preset duty cycle, and N represents the number of sub-modules in the supercapacitor converter valve.

8. The shockless charging method according to claim 1 further includes: All submodules in the supercapacitor converter valve are shut off, and the actual DC-side voltage is controlled to drop to the rated DC-side voltage of the modular multilevel converter valve through the modular multilevel converter valve.

9. A shockless charging device for a supercapacitor in a grid-type static synchronous condenser, comprising: Control module, first charging module and second charging module; The control module is used to control the actual DC side voltage of the modular multilevel converter valve according to the DC side reference voltage of the modular multilevel converter valve in the grid-type static synchronous condenser. The first charging module is used to control the actual voltage on the DC side to rise to a preset first voltage threshold according to a preset first rising slope, and to perform uncontrolled rectified charging on the supercapacitor converter valve in the grid-type static synchronous condenser. The second charging module is used to control the actual DC side voltage to rise to a preset second voltage threshold according to a preset second rising slope, and to perform impact-free charging of the supercapacitor converter valve according to a preset duty cycle. Wherein, the preset second voltage threshold is greater than the preset first voltage threshold.

10. The shockless charging device according to claim 9, wherein, The control module is used for: Based on the DC-side reference voltage, the DC-side actual voltage is subjected to proportional-integral control to make the DC-side actual voltage 0.

11. The shockless charging device according to claim 9, wherein, The first charging module is used for: Shut down all sub-modules in the supercapacitor converter valve and close the DC switch between the modular multilevel converter valve and the supercapacitor converter valve; The actual DC voltage is gradually increased according to the preset first rising slope, and the supercapacitor in the submodule is charged by uncontrolled rectification through the anti-parallel diode of the power device in the submodule. When the actual voltage on the DC side rises to the preset first voltage threshold, all submodules undergo an electrical self-test. If any submodule fails, all submodules stop uncontrolled rectifier charging and are then repaired.

12. The shockless charging device according to claim 9, wherein, The preset first voltage threshold satisfies: U dcset1 =N·U dc_start ; Among them, U dcset1 U represents the preset first voltage threshold, N represents the number of submodules in the supercapacitor converter valve, and U represents the number of submodules in the supercapacitor converter valve. dc_start This indicates the startup voltage of the drive module used to send drive signals to the submodule.

13. The shockless charging device according to claim 9, wherein, The second charging module is used for: The actual DC voltage is gradually increased according to the preset second rising slope, and the supercapacitor converter valve is charged without impact according to the preset duty cycle. Collect the DC voltage of each of the shutdown submodules and the bypassed submodules, and select the maximum value of the DC voltage of the shutdown submodule and the minimum value of the DC voltage of the bypassed submodule. When the voltage difference between the maximum DC voltage of the shutdown submodule and the minimum DC voltage of the bypassed submodule is greater than a preset third voltage threshold, the submodule corresponding to the minimum DC voltage of the bypassed submodule is shut down, and the submodule corresponding to the maximum DC voltage of the shutdown submodule is bypassed. If the DC voltage on the DC side rises to the preset second voltage threshold, and the DC voltage of the submodule is within the preset voltage range, then the supercapacitor converter valve completes shockless charging; otherwise, the supercapacitor converter valve continues to be charged shocklessly according to the preset duty cycle until the DC voltage of the submodule is within the preset voltage range.

14. The shockless charging device according to claim 9, wherein, The preset second voltage threshold satisfies: U dcset2 =(N-1)U scn ; Among them, U dcset2 U represents the preset second voltage threshold, N represents the number of submodules in the supercapacitor converter valve, and U represents the number of submodules in the supercapacitor converter valve. scn This indicates the rated voltage of the submodule.

15. The shockless charging device according to claim 9, wherein, The preset duty cycle satisfies: Wherein, D represents the preset duty cycle, and N represents the number of sub-modules in the supercapacitor converter valve.

16. The shockless charging device according to claim 9, wherein, The control module is also used for: All submodules in the supercapacitor converter valve are shut off, and the actual DC-side voltage is controlled to drop to the rated DC-side voltage of the modular multilevel converter valve through the modular multilevel converter valve.

17. A computer device, comprising: One or more processors; The one or more processors are used to store one or more programs; When the one or more programs are executed by the one or more processors, the shockless charging method according to any one of claims 1 to 8 is implemented.

18. A computer-readable storage medium, wherein, It contains a computer program, which, when executed, implements the shockless charging method according to any one of claims 1 to 8.

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