Impact-free charging method and device for supercapacitors in network-building static synchronous condensers

Abstract

The present application provides a method and device for impact-free charging of supercapacitors in a grid-type static synchronous condenser. The actual DC side voltage of the modular multilevel converter valve is controlled according to the DC side reference voltage of the modular multilevel converter valve. The actual DC side voltage is controlled to increase to a preset first voltage threshold according to a preset first rising slope, and the supercapacitor converter valve is charged with uncontrolled rectification. The actual DC side voltage is controlled to increase to a preset second voltage threshold according to a preset second rising slope, and the supercapacitor converter valve is charged with impact-free charging according to a preset duty cycle. By controlling the actual DC side voltage to charge the supercapacitor converter valve in different ways, the present application not only improves the charging efficiency of the supercapacitor converter valve, thereby improving the starting efficiency of the grid-type static synchronous condenser, but also has no impact on the AC system, that is, achieving impact-free charging of the supercapacitor converter valve.

Description

Technical Field

[0001] The present application relates to the field of flexible power transmission technology, and in particular to a method and device for charging a supercapacitor in a grid-connected static synchronous condenser without impact. Background Art

[0002] As power system construction accelerates, renewable energy sources are becoming the primary source of new installed capacity and power generation. As renewable energy penetration continues to increase, the power system is becoming increasingly electronic, significantly altering the operational mechanisms and safety and stability characteristics of the previously synchronous generator-based power system.

[0003] To improve the reactive power and voltage control capabilities of power systems that include renewable energy (referred to as new power systems), grid-connected static synchronous compensators (STATCOMs) are typically installed within renewable energy stations and AC collection stations. A STATCOM is a reactive power compensation device whose primary function is to provide or absorb reactive power to improve the power factor and maintain voltage stability of new power systems.

[0004] The voltage and inertia support device provided by the related art may include a modular multilevel converter valve (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 submodules, each of which may include a battery and a slow-start resistor. Due to the energy loss in the slow-start resistor, the charging efficiency of the energy storage converter valve is low, which in turn leads to low starting efficiency of the voltage and inertia support device. Summary of the Invention

[0005] To address the low startup efficiency issue in the prior art, this application provides a method for non-impact charging of supercapacitors in a grid-type static synchronous condenser. The grid-type static synchronous condenser, serving as a voltage and inertia support device, may include a modular multilevel converter valve and a supercapacitor converter valve. The AC side of the modular multilevel converter valve can be connected to an AC grid, and the DC side of the modular multilevel converter valve can be connected to the supercapacitor converter valve via a DC switch. The supercapacitor converter valve may include multiple submodules connected in series. Each submodule may include a supercapacitor.

[0006] The impact-free charging method provided by this application may include:

[0007] The actual DC side voltage of the modular multilevel converter valve in the grid-type static synchronous condenser is controlled according to the DC side reference voltage of the modular multilevel converter valve.

[0008] The actual voltage on the DC side is controlled to increase to a preset first voltage threshold according to a preset first rising slope, and uncontrolled rectification and charging are performed on the supercapacitor converter valve in the grid-type static synchronous phase regulator.

[0009] The actual voltage on the DC side is controlled to increase 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.

[0010] The preset second voltage threshold is greater than the preset first voltage threshold.

[0011] In some possible implementations, controlling the DC-side actual voltage of the modular multilevel converter valves in a grid-type static synchronous condenser according to the DC-side reference voltage of the modular multilevel converter valves includes:

[0012] According to the DC side reference voltage, the DC side actual voltage is proportionally and integrally controlled so that the DC side actual voltage is 0.

[0013] In some other possible implementations, controlling the actual DC side voltage to increase to a preset first voltage threshold according to a preset first rising slope, and performing uncontrolled rectification and charging on the supercapacitor converter valve in the grid-type static synchronous condenser, includes:

[0014] All submodules in the supercapacitor converter valve are turned off, and the DC switch between the modular multi-level converter valve and the supercapacitor converter valve is closed.

[0015] The actual voltage on the DC side is controlled to gradually increase according to a 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.

[0016] When the actual voltage on the DC side rises to a preset first voltage threshold, all submodules are powered on for self-test. If any submodule fails, all submodules stop uncontrolled rectification and charging and undergo maintenance.

[0017] Exemplarily, the preset first voltage threshold satisfies:

[0018] U dcset1 =N·U dc_start

[0019] Among them, U dcset1 represents the preset first voltage threshold, N represents the number of supercapacitor converter valve neutron modules, U dc_start Indicates the starting voltage of the driver module used to send driving signals to the submodules.

[0020] In some further possible implementations, controlling the actual DC side voltage to increase to a preset second voltage threshold according to a preset second rising slope, and performing impact-free charging on the supercapacitor converter valve according to a preset duty cycle, includes:

[0021] The actual voltage on the DC side is controlled to gradually increase according to a preset second rising slope, and the supercapacitor converter valve is charged without impact according to a preset duty cycle.

[0022] The DC voltages of all shutdown submodules and all bypassed submodules are collected, and the maximum DC voltage of the shutdown submodule and the minimum DC voltage of the bypassed submodule are selected.

[0023] When the voltage difference between the maximum DC voltage of the shut-down 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 shut-down submodule is bypassed.

[0024] When the actual DC side voltage rises to a preset second voltage threshold, if the DC voltage of the submodule is within the preset voltage range, the supercapacitor converter valve completes impactless charging. Otherwise, impactless charging of the supercapacitor converter valve continues according to the preset duty cycle until the DC voltage of the submodule is within the preset voltage range.

[0025] Optionally, the preset second voltage threshold satisfies:

[0026] U dcset2 =(N-1)U scn

[0027] Among them, U dcset2 represents the preset second voltage threshold, N represents the number of supercapacitor converter valve neutron modules, U scn Indicates the rated voltage of the submodule.

[0028] Exemplarily, the preset duty cycle satisfies:

[0029]

[0030] Wherein, D represents a preset duty cycle, and N represents the number of submodules in the supercapacitor converter valve.

[0031] Furthermore, the impact-free charging method provided by the present application also includes:

[0032] All submodules in the supercapacitor converter valve are turned off, and the actual DC side voltage is controlled by the modular multi-level converter valve to drop to the DC side rated voltage of the modular multi-level converter valve.

[0033] On the other hand, the present application also provides a non-impact charging device for supercapacitors in a networked static synchronous condenser, comprising:

[0034] The control module is used to control the DC side actual voltage of the modular multilevel converter valve in the grid-type static synchronous phase condenser according to the DC side reference voltage of the modular multilevel converter valve.

[0035] The first charging module is used to control the actual voltage on the DC side to increase to a preset first voltage threshold according to a preset first rising slope, and to perform uncontrolled rectification and charging on the supercapacitor converter valve in the grid-type static synchronous phase regulator.

[0036] The second charging module is used to control the actual voltage on the DC side to increase to a preset second voltage threshold according to a preset second rising slope, and to perform impact-free charging on the supercapacitor converter valve according to a preset duty cycle.

[0037] The preset second voltage threshold is greater than the preset first voltage threshold.

[0038] In a possible implementation, the control module is specifically configured to:

[0039] According to the DC side reference voltage, the DC side actual voltage is proportionally and integrally controlled so that the DC side actual voltage is 0.

[0040] In another possible implementation, the first charging module is specifically configured to:

[0041] All submodules in the supercapacitor converter valve are turned off, and the DC switch between the modular multi-level converter valve and the supercapacitor converter valve is closed.

[0042] The actual voltage on the DC side is controlled to gradually increase according to a 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.

[0043] When the actual voltage on the DC side rises to a preset first voltage threshold, all submodules are powered on for self-test. If any submodule fails, all submodules stop uncontrolled rectification and charging and undergo maintenance.

[0044] Exemplarily, the preset first voltage threshold satisfies:

[0045] U dcset1 =N·U dc_start

[0046] Among them, U dcset1 represents the preset first voltage threshold, N represents the number of supercapacitor converter valve neutron modules, U dc_start Indicates the starting voltage of the driver module used to send driving signals to the submodules.

[0047] In another possible implementation, the second charging module is specifically configured to:

[0048] The actual voltage on the DC side is controlled to gradually increase according to a preset second rising slope, and the supercapacitor converter valve is charged without impact according to a preset duty cycle.

[0049] The DC voltages of all shutdown submodules and all bypassed submodules are collected, and the maximum DC voltage of the shutdown submodule and the minimum DC voltage of the bypassed submodule are selected.

[0050] When the voltage difference between the maximum DC voltage of the shut-down 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 shut-down submodule is bypassed.

[0051] When the actual DC side voltage rises to a preset second voltage threshold, if the DC voltage of the submodule is within the preset voltage range, the supercapacitor converter valve completes impactless charging. Otherwise, impactless charging of the supercapacitor converter valve continues according to the preset duty cycle until the DC voltage of the submodule is within the preset voltage range.

[0052] Optionally, the preset second voltage threshold satisfies:

[0053] U dcset2 =(N-1)U scn

[0054] Among them, U dcset2 represents the preset second voltage threshold, N represents the number of supercapacitor converter valve neutron modules, U scn Indicates the rated voltage of the submodule.

[0055] Exemplarily, the preset duty cycle satisfies:

[0056]

[0057] Wherein, D represents a preset duty cycle, and N represents the number of submodules in the supercapacitor converter valve.

[0058] Furthermore, the control module is also used to:

[0059] All submodules in the supercapacitor converter valve are turned off, and the actual DC side voltage is controlled by the modular multi-level converter valve to drop to the DC side rated voltage of the modular multi-level converter valve.

[0060] On the other hand, the present application also provides a computer device, including: one or more processors.

[0061] A processor is used to execute one or more programs.

[0062] When one or more programs are executed by one or more processors, the impactless charging method described above is implemented.

[0063] In another aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the impact-free charging method described above.

[0064] Compared with the prior art, the present invention has the following advantages:

[0065] In the impact-free charging method for supercapacitors in a grid-type static synchronous condenser provided in the present application, the actual DC-side voltage of the modular multilevel converter valves in the grid-type static synchronous condenser is controlled based on the DC-side reference voltage of the modular multilevel converter valves in the grid-type static synchronous condenser. The actual DC-side voltage is controlled to increase to a preset first voltage threshold according to a preset first rising slope, and the supercapacitor converter valves in the grid-type static synchronous condenser are charged with uncontrolled rectification. The actual DC-side voltage is controlled to increase to a preset second voltage threshold according to a preset second rising slope, and the supercapacitor converter valves are charged impact-free according to a preset duty cycle. It can be seen that the present application improves the charging efficiency of the supercapacitor converter valves by controlling the actual DC-side voltage to charge the supercapacitor converter valves in different ways, thereby improving the startup efficiency of the grid-type static synchronous condenser.

[0066] In the present application, when the actual voltage on the DC side is 0, closing the DC switch between the modular multi-level converter valve and the supercapacitor converter valve will not cause any voltage or current shock to the supercapacitor converter valve and the AC system connected to the modular multi-level converter valve, that is, it will not affect the normal operation of the AC system, and will not affect the subsequent uncontrolled rectification charging and impact-free charging of the supercapacitor converter valve.

[0067] In the present application, when the voltage difference between the maximum DC voltage of the shut-off 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 shut-off submodule is bypassed. This can control the DC voltage balance between the submodules, and there is no impact on the AC system during the entire charging process of the supercapacitor converter valve, that is, to achieve impact-free charging of the supercapacitor converter valve.

[0068] In the present application, the supercapacitor converter valve of the grid-type static synchronous condenser does not need to be separately provided with a slow-start resistor, thereby avoiding the power loss of the slow-start resistor and further improving the starting efficiency of the grid-type static synchronous condenser. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0070] Figure 1 This is a schematic structural diagram of a networked static synchronous condenser in an embodiment of the present application;

[0071] Figure 2 This is a schematic structural diagram of a submodule in an embodiment of the present application;

[0072] Figure 3 Another schematic structural diagram of a submodule in an embodiment of the present application;

[0073] Figure 4 This is a schematic flow chart of a method for charging a supercapacitor without impact in an embodiment of the present application;

[0074] Figure 5 This is a schematic structural diagram of a non-impact charging device for a supercapacitor in an embodiment of the present application. DETAILED DESCRIPTION

[0075] The technical solution in this application will be described below with reference to the accompanying drawings.

[0076] The terms "first," "second," and the like in the description, embodiments, claims, and drawings of this application are used solely for descriptive purposes and are not to be construed as indicating or implying relative importance or order. Furthermore, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions, such as, for example, inclusion of 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.

[0077] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0078] Example 1:

[0079] The embodiment of the present application provides a method for charging supercapacitors in a networked static synchronous condenser without impact. Figure 1 As shown, a grid-type static synchronous condenser (STATCOM) can include a modular multi-level converter valve 1 and a supercapacitor converter valve 2. The AC side of the modular multi-level converter valve 1 can be connected to the AC grid G ​​through an AC switch QFac, and the DC side of the modular multi-level converter valve 1 can be connected to the supercapacitor converter valve 2 through a DC switch QF1dc and a DC switch QF2dc. The supercapacitor converter valve 2 can include multiple sub-modules connected in series. The multiple sub-modules in series include Figure 1 There are N sub-modules in total, including sub-module SC-SM1, sub-module SC-SM2, ..., sub-module SC-SMN-1, and sub-module SC-SMN.

[0080] The modular multilevel converter valve 1 includes a Phase A arm, a Phase B arm, and a Phase C arm. Each Phase arm includes an upper arm and a lower arm, each of which includes multiple submodules connected in series. For example, the Phase A arm includes submodules SMa1 through SMa2N, the Phase B arm includes submodules SMb1 through SMb2N, and the Phase C arm includes submodules SMc1 through SMc2N. Figure 1 Where L is the bridge arm reactance. dc Indicates the actual DC side voltage of the modular multi-level converter valve 1.

[0081] like Figure 2As shown, each submodule can be a half-bridge structure, including a power device T1, a power device T2 and a supercapacitor SC. Both the power device T1 and the power device T2 can be an insulated gate bipolar transistor (IGBT), and the IGBT has a diode in anti-parallel. The first pole of the power device T1 is connected to the first pole of the supercapacitor SC, the second pole of the power device T1 is connected to the first pole of the power device T2, serving as the first end of the submodule, and the second pole of the power device T2 is connected to the second pole of the supercapacitor SC, serving as the second end of the submodule.

[0082] like Figure 3 As shown, 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 the IGBTs are anti-parallel connected with a diode.

[0083] like Figure 4 As shown, the impact-free charging method 100 provided in the embodiment of the present application includes the following steps:

[0084] Step S1: Based on the DC side reference voltage of the modular multi-level converter valve 1 (which can be represented by U ref (represents) the actual DC side voltage U that controls the modular multi-level converter valve 1 dc .

[0085] Step S2: Control the actual DC side voltage U according to the preset first rising slope (which can be represented by k1) dc Increase to the preset first voltage threshold (U dcset1 ), and the supercapacitor converter valve 2 is charged with uncontrolled rectification.

[0086] Step S3: Control the actual DC side voltage U according to the preset second rising slope (which can be represented by k2) dc Increase to the preset second voltage threshold (U dcset2 denoted by ), and the supercapacitor converter valve 2 is charged without impact according to a preset duty cycle (which can be represented by D).

[0087] The preset second voltage threshold U dcset2 Greater than the preset first voltage threshold U dcset1 The first rising slope and the second rising slope may be the same or different, and this embodiment of the present application does not limit this.

[0088] In some embodiments, in step S1, the DC side reference voltage U of the modular multi-level converter valve 1 is ref Control the actual DC side voltage U of the modular multi-level converter valve dc ,include:

[0089] According to the DC side reference voltage U ref , the actual DC side voltage U dc Perform proportional integral control (PI control) to make the actual DC side voltage U dc is 0.

[0090] In some other embodiments, in step S2, the actual DC side voltage U is controlled according to the preset first rising slope k1. dc Increases to the preset first voltage threshold U dcset1 , and performs uncontrolled rectification and charging on the supercapacitor converter valve 2, including:

[0091] All submodules in the supercapacitor converter valve 2 are turned off, and the DC switches QF1dc and QF2dc between the modular multi-level converter valve 1 and the supercapacitor converter valve 2 are closed.

[0092] Control the actual DC side voltage U according to the preset first rising slope k1 dc As the voltage gradually increases, the supercapacitor SC in the submodule is charged by uncontrolled rectification through the anti-parallel diode of the power device in the submodule.

[0093] The actual voltage on the DC side U dc Increases to the preset first voltage threshold U dcset1 In this case, all submodules will be powered on for self-test. If any submodule fails, all submodules will stop uncontrolled rectification and charging and carry out maintenance.

[0094] For example, the preset first voltage threshold U dcset1 satisfy:

[0095] U dcset1 =N·U dc_start

[0096] Among them, U dcset1 represents the preset first voltage threshold, N represents the number of submodules in the supercapacitor converter valve 2, and U dc_start Indicates the starting voltage of the driver module used to send drive signals to the submodules. Driver modules usually use DC power.

[0097] In some other embodiments, in step S3, the actual DC side voltage U is controlled according to the preset second rising slope k2. dc Increases to the preset second voltage threshold U dcset2, and charging the supercapacitor converter valve 2 without impact according to the preset duty cycle D, including:

[0098] Control the DC side actual voltage U 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.

[0099] Collect all the shut-off submodules and all the bypassed submodules (which can be turned on Figure 3 The DC voltage of each power device T2 bypass submodule) and the maximum DC voltage of the shutdown submodule are selected (U sc_max and the minimum DC voltage of the bypassed submodule (which can be represented by U sc_min express).

[0100] When the DC voltage maximum value U sc_max (The corresponding submodule can be recorded as submodule SC-SM j ) and the minimum DC voltage U of the bypassed submodule sc_min (The corresponding submodule can be recorded as submodule SC-SM k ) (can be expressed as ΔU sc If the DC voltage of the bypassed submodule is greater than a preset third voltage threshold (eg, 20V), the DC voltage minimum value U sc_min The corresponding submodule (i.e. shut down submodule SC-SM k ), and bypass the maximum DC voltage U of the shutdown submodule sc_max The corresponding submodule (ie bypass submodule SC-SM j ).

[0101] The actual voltage on the DC side U dc Increases to the preset second voltage threshold U dcset2 In the case of the submodule, if the DC voltage is within the preset voltage range (which can be 0.95U scn ~1.05U scn , where U scn If the DC voltage of the submodule is within the rated voltage range, the supercapacitor converter valve 2 completes impact-free charging. Otherwise, the supercapacitor converter valve 2 continues to be charged impact-free according to the preset duty cycle D until the DC voltage of the submodule is within the preset voltage range.

[0102] Optionally, the preset second voltage threshold satisfies:

[0103] U dcset2 =(N-1)U scn

[0104] Among them, U dcset2represents the preset second voltage threshold, N represents the number of submodules in the supercapacitor converter valve 2, and U scn Indicates the rated voltage of the submodule.

[0105] Exemplarily, the preset duty cycle satisfies:

[0106]

[0107] Wherein, D represents a preset duty cycle, and N represents the number of submodules in the supercapacitor converter valve.

[0108] Furthermore, the impact-free charging method 100 provided in the embodiment of the present application further includes:

[0109] All submodules of the supercapacitor converter valve 2 are turned off, and the actual DC side voltage U is controlled by the modular multi-level converter valve 1. dc The voltage drops to the rated DC side voltage of the modular multilevel converter valve 1.

[0110] In summary, the charging method provided in the embodiment of the present application does not involve the addition or change of hardware and has strong engineering practicality.

[0111] Example 2:

[0112] Based on the same inventive concept, the present invention also provides a non-impact charging device for supercapacitors in a grid-type static synchronous condenser. For an introduction to a grid-type static synchronous condenser, please refer to the above text and the accompanying drawings, and the present invention will not elaborate on this in detail.

[0113] like Figure 5 As shown, the charging device 200 includes:

[0114] The control module 21 is used to control the DC side reference voltage U of the modular multi-level converter valve 1 according to the reference voltage U ref Control the actual DC side voltage U of the modular multi-level converter valve 1 dc .

[0115] The first charging module 22 is used to control the actual DC side voltage U according to the preset first rising slope k1 dc Increases to the preset first voltage threshold U dcset1 , and perform uncontrolled rectification and charging on the supercapacitor converter valve 2.

[0116] The second charging module 23 is used to control the actual DC side voltage U according to the preset second rising slope k2 dc Increases to the preset second voltage threshold U dcset2 , and the supercapacitor converter valve 2 is charged without impact according to the preset duty cycle D.

[0117] The preset second voltage threshold Udcset2 Greater than the preset first voltage threshold U dcset1 The first rising slope and the second rising slope may be the same or different, and this embodiment of the present application does not limit this.

[0118] In some embodiments, the control module 21 is specifically configured to:

[0119] According to the DC side reference voltage U ref , the actual DC side voltage U dc Perform proportional integral control to make the actual DC side voltage U dc is 0.

[0120] In some other embodiments, the first charging module 22 is specifically configured to:

[0121] All submodules in the supercapacitor converter valve 2 are turned off, and the DC switches QF1dc and QF2dc between the modular multi-level converter valve 1 and the supercapacitor converter valve 2 are closed.

[0122] Control the actual DC side voltage U according to the preset first rising slope k1 dc As the voltage gradually increases, the supercapacitor SC in the submodule is charged by uncontrolled rectification through the anti-parallel diode of the power device in the submodule.

[0123] The actual voltage on the DC side U dc Increases to the preset first voltage threshold U dcset1 In this case, all submodules will be powered on for self-test. If any submodule fails, all submodules will stop uncontrolled rectification and charging and carry out maintenance.

[0124] For example, the preset first voltage threshold U dcset1 satisfy:

[0125] U dcset1 =N·U dc_start

[0126] Among them, U dcset1 represents the preset first voltage threshold, N represents the number of supercapacitor converter valve neutron modules, U dc_start Indicates the starting voltage of the driver module used to send driving signals to the submodules.

[0127] In some further embodiments, the second charging module 23 is specifically configured to:

[0128] Control the DC side actual voltage U 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.

[0129] Collect all the shut-off submodules and all the bypassed submodules (which can be turned on Figure 3 The DC voltage of each power device T2 bypass submodule) and the maximum DC voltage of the shutdown submodule are selected (U sc_max and the minimum DC voltage of the bypassed submodule (which can be represented by U sc_min express).

[0130] When the DC voltage maximum value U sc_max (The corresponding submodule can be recorded as submodule SC-SM j ) and the minimum DC voltage U of the bypassed submodule sc_min (The corresponding submodule can be recorded as submodule SC-SM k ) (can be expressed as ΔU sc If the DC voltage of the bypassed submodule is greater than a preset third voltage threshold (eg, 20V), the DC voltage minimum value U sc_min The corresponding submodule (i.e. shut down submodule SC-SM k ), and bypass the maximum DC voltage U of the shutdown submodule sc_max The corresponding submodule (ie bypass submodule SC-SM j ).

[0131] The actual voltage on the DC side U dc Increases to the preset second voltage threshold U dcset2 In the case of the submodule, if the DC voltage is within the preset voltage range (which can be 0.95U scn ~1.05U scn , where U scn If the DC voltage of the submodule is within the rated voltage range, the supercapacitor converter valve 2 completes impact-free charging. Otherwise, the supercapacitor converter valve 2 continues to be charged impact-free according to the preset duty cycle D until the DC voltage of the submodule is within the preset voltage range.

[0132] Optionally, the preset second voltage threshold satisfies:

[0133] U dcset2 =(N-1)U scn

[0134] Among them, U dcset2 represents the preset second voltage threshold, N represents the number of submodules in the supercapacitor converter valve 2, and U scn Indicates the rated voltage of the submodule.

[0135] Exemplarily, the preset duty cycle satisfies:

[0136]

[0137] Wherein, D represents a preset duty cycle, and N represents the number of submodules in the supercapacitor converter valve.

[0138] Furthermore, the control module 21 is further configured to:

[0139] All submodules of the supercapacitor converter valve 2 are turned off, and the actual DC side voltage U is controlled by the modular multi-level converter valve 1. dc The voltage drops to the rated DC side voltage of the modular multilevel converter valve 1.

[0140] Example 3:

[0141] Based on the same inventive concept, an embodiment of the present application also provides a computer device, which includes a processor and a memory, the memory being used to store a computer program, the computer program including program instructions, and the processor being used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for 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 impactless charging method provided in the above embodiment.

[0142] Example 4:

[0143] Based on the same inventive concept, an embodiment of the present application also provides a computer-readable storage medium, specifically a computer-readable storage medium (Memory). The computer-readable storage medium is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space that stores the terminal's operating system. In addition, the storage space also stores one or more instructions suitable for being loaded and executed by the 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. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the impactless charging method provided in the above embodiment.

[0144] Those skilled in the art will appreciate that embodiments of the application may be provided as methods, systems, or computer program products. Thus, the application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0145] The application is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as a combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0146] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1The function specified in one or more boxes.

[0147] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0148] The above are merely embodiments of the application and are not intended to limit the application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the application are included in the scope of the claims of the pending application.

Claims

1. A method for charging supercapacitors in a grid-connected static synchronous condenser without impact, characterized in that: include: controlling the actual DC side voltage of the modular multilevel converter valve in the grid-type static synchronous condenser according to the DC side reference voltage of the modular multilevel converter valve; Controlling the actual voltage on the DC side to increase to a preset first voltage threshold according to a preset first rising slope, and performing uncontrolled rectification and charging on the supercapacitor converter valve in the grid-type static synchronous condenser; Controlling the actual DC side voltage to increase to a preset second voltage threshold according to a preset second rising slope, and performing impact-free 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; The controlling of the DC side actual voltage of the modular multilevel converter valve according to the DC side reference voltage of the modular multilevel converter valve in the gridded static synchronous condenser comprises: Performing proportional-integral control on the actual DC side voltage according to the DC side reference voltage, so that the actual DC side voltage is 0; The step of controlling the actual DC side voltage to increase to a preset second voltage threshold according to a preset second rising slope, and performing impact-free charging on the supercapacitor converter valve according to a preset duty cycle, includes: Controlling the actual DC side voltage to gradually increase according to the preset second rising slope, and performing impact-free charging on the supercapacitor converter valve according to the preset duty cycle; Collecting the DC voltages of all shutdown submodules and all bypassed submodules, and selecting the maximum DC voltage of the shutdown submodule and the minimum 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; When the actual DC side voltage rises to the preset second voltage threshold, if the DC voltage of the submodule is within the preset voltage range, the supercapacitor converter valve completes impact-free charging; otherwise, the supercapacitor converter valve continues to be impact-free charged according to the preset duty cycle until the DC voltage of the submodule is within the preset voltage range; The preset duty cycle satisfies: Wherein, D represents the preset duty cycle, and N represents the number of submodules in the supercapacitor converter valve.

2. The impact-free charging method according to claim 1, wherein: The step of controlling the actual DC side voltage to increase to a preset first voltage threshold according to a preset first rising slope, and performing uncontrolled rectification and charging on the supercapacitor converter valve in the grid-type static synchronous condenser, includes: Turning off all submodules in the supercapacitor converter valve and closing the DC switch between the modular multi-level converter valve and the supercapacitor converter valve; Controlling the actual voltage on the DC side to gradually increase according to the preset first rising slope, and charging the supercapacitor in the submodule 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 are powered on for self-inspection. If any submodule fails, all submodules stop uncontrolled rectification and charging and undergo maintenance.

3. The impact-free charging method according to claim 1, wherein: The preset first voltage threshold satisfies: U dcset1 =N·U dc_start Among them, U dcset1 represents the preset first voltage threshold, N represents the number of submodules in the supercapacitor converter valve, U dc_start Indicates the starting voltage of the driving module used to send the driving signal to the submodule.

4. The impact-free charging method according to claim 1, wherein: The preset second voltage threshold satisfies: U dcset2 =(N-1)U scn Among them, U dcset2 represents the preset second voltage threshold, N represents the number of submodules in the supercapacitor converter valve, U scn Indicates the rated voltage of the submodule.

5. The impact-free charging method according to claim 1, wherein: The impact-free charging method further comprises: All submodules in the supercapacitor converter valve are turned off, and the actual DC side voltage is controlled to drop to the DC side rated voltage of the modular multilevel converter valve through the modular multilevel converter valve.

6. A non-impact charging device for supercapacitors in a network-forming static synchronous condenser, characterized in that: include: a control module, configured to control the DC side actual voltage of the modular multilevel converter valve in the grid-type static synchronous condenser according to the DC side reference voltage of the modular multilevel converter valve; a first charging module, configured to control the actual DC side voltage to increase to a preset first voltage threshold according to a preset first rising slope, and to perform uncontrolled rectification and charging on the supercapacitor converter valve in the grid-type static synchronous condenser; a second charging module, configured to control the DC side actual voltage to increase to a preset second voltage threshold according to a preset second rising slope, and to perform impact-free 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; The control module is specifically used for: Performing proportional-integral control on the actual DC side voltage according to the DC side reference voltage, so that the actual DC side voltage is 0; The second charging module is specifically configured to: Controlling the actual DC side voltage to gradually increase according to the preset second rising slope, and performing impact-free charging on the supercapacitor converter valve according to the preset duty cycle; Collecting the DC voltages of all shutdown submodules and all bypassed submodules, and selecting the maximum DC voltage of the shutdown submodule and the minimum 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; When the actual DC side voltage rises to the preset second voltage threshold, if the DC voltage of the submodule is within the preset voltage range, the supercapacitor converter valve completes impact-free charging; otherwise, the supercapacitor converter valve continues to be impact-free charged according to the preset duty cycle until the DC voltage of the submodule is within the preset voltage range; The preset duty cycle satisfies: Wherein, D represents the preset duty cycle, and N represents the number of submodules in the supercapacitor converter valve.

7. The impact-free charging device according to claim 6, characterized in that: The first charging module is specifically configured to: Turning off all submodules in the supercapacitor converter valve and closing the DC switch between the modular multi-level converter valve and the supercapacitor converter valve; Controlling the actual voltage on the DC side to gradually increase according to the preset first rising slope, and charging the supercapacitor in the submodule 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 are powered on for self-inspection. If any submodule fails, all submodules stop uncontrolled rectification and charging and undergo maintenance.

8. The impact-free charging device according to claim 6, characterized in that: The preset first voltage threshold satisfies: U dcset1 =N·U dc_start Among them, U dcset1 represents the preset first voltage threshold, N represents the number of submodules in the supercapacitor converter valve, U dc_start Indicates the starting voltage of the driving module used to send the driving signal to the submodule.

9. The impact-free charging device according to claim 6, characterized in that: The preset second voltage threshold satisfies: U dcset2 =(N-1)U scn Among them, U dcset2 represents the preset second voltage threshold, N represents the number of submodules in the supercapacitor converter valve, U scn Indicates the rated voltage of the submodule.

10. The impact-free charging device according to claim 6, characterized in that: The control module is further configured to: All submodules in the supercapacitor converter valve are turned off, and the actual DC side voltage is controlled to drop to the DC side rated voltage of the modular multilevel converter valve through the modular multilevel converter valve.

11. A computer device, characterized in that: include: one or more processors; The processor is configured to store one or more programs; When the one or more programs are executed by the one or more processors, the impactless charging method according to any one of claims 1 to 5 is implemented.

12. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed, the impact-free charging method according to any one of claims 1 to 5 is implemented.

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