Control method and device of direct current energy consumption device
By controlling the DC bus voltage, and investing or cutting off the submodules of the DC energy-consuming device in batches, the problems of high cost and uneven energy dissipation in the prior art are solved, and the effects of low cost and balanced dissipation are achieved.
Patent Information
- Application Number
- CN202510010195.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2025-05-16
AI Technical Summary
The existing DC energy-consuming devices are costly and have slow energy dissipation speed, so they cannot achieve balanced dissipation of all submodules and need to be equipped with cooling equipment.
By obtaining the DC bus voltage, the submodule is controlled to input batches when the voltage is higher than the start threshold; when the voltage is lower than the preset lower limit of the hysteresis ring, the submodule is controlled to cut off batches to achieve energy equalization dissipation.
Energy balanced dissipation is achieved without the need to be equipped with cooling equipment, reducing the cost of DC energy-consuming devices.
Smart Images
Figure CN120016426A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of direct current power transmission technology, and in particular to a control method and device for a direct current energy consumption device. Background Art
[0002] Offshore wind power has become one of the key development targets of renewable energy power generation due to its characteristics of not occupying land resources, large single-unit capacity, and not being affected by topography. AC transmission has become the preferred option in the offshore area due to its low cost advantage, while offshore wind power in the offshore area generally adopts flexible DC transmission technology to achieve grid connection.
[0003] In a flexible DC transmission system, when a fault occurs in the AC main grid at the receiving end, the AC bus voltage drops, the output power of the receiving converter station will decrease, while the output power of the wind farm remains unchanged. The surplus power generated will continue to charge the submodule capacitors of the DC energy consumption device in the receiving converter station, causing overvoltage damage and triggering DC protection. In severe cases, it will cause a large area of wind turbines in the wind farm to be disconnected from the grid. Therefore, it is necessary to control the DC energy consumption device to convert the surplus power into energy dissipation, thereby realizing the AC low-voltage ride-through of the flexible DC transmission system.
[0004] At present, DC energy dissipation devices usually adopt a hybrid structure. The hybrid structure in the related art usually includes multiple submodules and a centralized resistor. Multiple submodules are connected in series with the centralized resistor. In the control process of the DC energy dissipation device in the related art, the submodules are usually put into operation one by one, the energy dissipation speed is slow, and the balanced dissipation of all submodules cannot be achieved. Cooling equipment is required, resulting in high cost of the DC energy dissipation device. Summary of the invention
[0005] In order to solve the problem of high cost in the prior art, the present application provides a control method for a DC energy consumption device, which may include:
[0006] The DC bus voltage is obtained. When the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device, the submodules in the DC energy consumption device are controlled to be put into operation in batches. When the DC bus voltage is lower than the preset hysteresis lower limit voltage, the submodules are controlled to be removed in batches.
[0007] Optionally, one end of the DC energy consumption device is connected to the positive DC bus, and the other end of the DC energy consumption device is connected to the negative DC bus. The DC bus voltage is used to indicate the voltage difference between the positive DC bus and the negative DC bus.
[0008] The DC energy dissipation device comprises a plurality of submodules and a concentrated resistor. The plurality of submodules are sequentially connected in series and then connected in series with the concentrated resistor.
[0009] The submodule includes a first switch tube, a diode, a submodule capacitor, a second switch tube and a distributed resistor. The first pole of the first switch tube is connected to the anode of the diode as the first end of the submodule. The cathode of the diode, the first pole of the submodule capacitor and the first pole of the second switch tube are connected, the second pole of the second switch tube is connected to the first end of the distributed resistor, and the second pole of the first switch tube, the second pole of the submodule capacitor and the second end of the distributed resistor are connected as the second end of the submodule.
[0010] In some possible implementations, when the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device, the submodules of the DC energy consumption device are controlled to be put into operation in batches, including:
[0011] The first switch tube is controlled to be turned off, the absorbed power of the DC energy consumption device gradually increases from 0 to the rated power of the DC energy consumption device, the DC bus voltage gradually increases from the starting threshold voltage to the maximum voltage of the DC bus, and then the DC bus voltage gradually decreases to the initial voltage of all sub-modules.
[0012] Furthermore, when the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device, after controlling the submodules of the DC energy consumption device to be put into operation in batches, the control method further includes:
[0013] The first switch tube is controlled to be turned off, so that all sub-modules are put into operation, the absorbed power of the DC energy consumption device is maintained at the rated power of the DC energy consumption device, and the DC bus voltage gradually decreases from the initial voltage when all sub-modules are put into operation to the preset hysteresis lower limit voltage.
[0014] In some other possible implementations, when the DC bus voltage is lower than a preset hysteresis lower limit voltage, the control submodules are removed in batches, including:
[0015] The first switch tube is controlled to be turned on, the absorbed power of the DC energy consumption device is gradually reduced from the rated power of the DC energy consumption device to 0, and the DC bus voltage is gradually increased from the preset hysteresis lower limit voltage to the initial voltage at which all sub-modules are cut off.
[0016] Furthermore, when the DC bus voltage is lower than the preset hysteresis lower limit voltage, after the control submodules are removed in batches, the control method further includes:
[0017] The first switch tube is controlled to be turned on, the absorbed power of the DC energy consumption device is kept at 0, and the DC bus voltage gradually increases from the initial voltage after all sub-modules are cut off to the preset hysteresis upper limit voltage.
[0018] Optionally, the control method provided by the present application also includes:
[0019] The first switch tube and the second switch tube are both controlled to be turned off, and the charging voltage of the submodule capacitor gradually increases from the reference voltage of the submodule capacitor to a preset upper limit of the charging voltage.
[0020] The first switch tube is controlled to be turned off and the second switch tube is controlled to be turned on, and the charging voltage of the submodule capacitor is gradually reduced from a preset charging voltage upper limit to a preset charging voltage lower limit.
[0021] The first switch tube and the second switch tube are both controlled to be turned off, and the charging voltage of the submodule capacitor gradually increases from a preset charging voltage lower limit to a reference voltage of the submodule capacitor.
[0022] The preset upper limit of the charging voltage is the sum of the reference voltage of the submodule capacitor and the voltage fluctuation limit, and the preset lower limit of the charging voltage is the difference between the reference voltage of the submodule capacitor and the voltage fluctuation limit.
[0023] On the other hand, the present application provides a control device for a DC energy consumption device, characterized in that it includes:
[0024] The acquisition module is used to obtain the DC bus voltage.
[0025] The first control module is used to control the submodules of the DC energy consumption device to be put into operation in batches when the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device.
[0026] The second control module is used to control the submodules to be cut off in batches when the DC bus voltage is lower than a preset hysteresis lower limit voltage.
[0027] Optionally, one end of the DC energy consumption device is connected to the positive DC bus, and the other end of the DC energy consumption device is connected to the negative DC bus. The DC bus voltage is used to indicate the voltage difference between the positive DC bus and the negative DC bus.
[0028] The DC energy dissipation device comprises a plurality of submodules and a concentrated resistor. The plurality of submodules are sequentially connected in series and then connected in series with the concentrated resistor.
[0029] The submodule includes a first switch tube, a diode, a submodule capacitor, a second switch tube and a distributed resistor. The first pole of the first switch tube is connected to the anode of the diode as the first end of the submodule. The cathode of the diode, the first pole of the submodule capacitor and the first pole of the second switch tube are connected, the second pole of the second switch tube is connected to the first end of the distributed resistor, and the second pole of the first switch tube, the second pole of the submodule capacitor and the second end of the distributed resistor are connected as the second end of the submodule.
[0030] In a possible implementation, the first control module is specifically used to: control the first switch tube to turn off, the absorbed power of the DC energy consumption device gradually increases from 0 to the rated power of the DC energy consumption device, the DC bus voltage gradually increases from the starting threshold voltage to the maximum voltage of the DC bus, and then the DC bus voltage gradually decreases to the initial voltage of all sub-modules.
[0031] Furthermore, the first control module is also used to: control the first switch tube to turn off, so that all sub-modules are put into operation, the absorbed power of the DC energy consumption device is maintained at the rated power of the DC energy consumption device, and the DC bus voltage gradually decreases from the initial voltage when all sub-modules are put into operation to a preset hysteresis lower limit voltage.
[0032] In another possible implementation, the second control module is specifically used to: control the first switch tube to be turned on, the absorbed power of the DC energy consumption device is gradually reduced from the rated power of the DC energy consumption device to 0, and the DC bus voltage is gradually increased from the preset hysteresis lower limit voltage to the initial voltage at which all sub-modules are cut off.
[0033] Furthermore, the first control module is also used to: control the first switch tube to be turned on, the absorbed power of the DC energy consumption device is maintained at 0, and the DC bus voltage gradually increases from the initial voltage cut off from all sub-modules to a preset hysteresis upper limit voltage.
[0034] Optionally, the control device further includes a third control module, and the third control module is used to:
[0035] The first switch tube and the second switch tube are both controlled to be turned off, and the charging voltage of the submodule capacitor gradually increases from the reference voltage of the submodule capacitor to a preset upper limit of the charging voltage.
[0036] The first switch tube is controlled to be turned off and the second switch tube is controlled to be turned on, and the charging voltage of the submodule capacitor is gradually reduced from a preset charging voltage upper limit to a preset charging voltage lower limit.
[0037] The first switch tube and the second switch tube are both controlled to be turned off, and the charging voltage of the submodule capacitor gradually increases from a preset charging voltage lower limit to a reference voltage of the submodule capacitor.
[0038] The preset upper limit of the charging voltage is the sum of the reference voltage of the submodule capacitor and the voltage fluctuation limit, and the preset lower limit of the charging voltage is the difference between the reference voltage of the submodule capacitor and the voltage fluctuation limit.
[0039] On the other hand, the present application also provides a computer device, including: one or more processors.
[0040] A processor is used to execute one or more programs.
[0041] When one or more programs are executed by one or more processors, the control method as described above is implemented.
[0042] In another aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed, the control method described above is implemented.
[0043] Compared with the prior art, the beneficial effects of this application are:
[0044] In the control method provided by the present application, the DC bus voltage can be obtained. When the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device, the submodules in the DC energy consumption device are controlled to be put into operation in batches; when the DC bus voltage is lower than the preset hysteresis lower limit voltage, the submodules are controlled to be removed in batches. It can be seen that the present application implements batch-by-batch operation or removal of submodules in different scenarios, which can achieve balanced energy dissipation without the need for cooling equipment, thereby reducing the cost of the DC energy consumption device.
[0045] The control method provided in the present application performs hysteresis control on the DC bus voltage and the submodule capacitance respectively, has low requirements on the charging and discharging performance of the submodule capacitance, is easy to reduce the volume of the submodule, and realizes the lightweight design of the DC energy consumption device;
[0046] The control method provided in the present application effectively reduces the current conversion rate when the sub-module is switched in and out, suppresses electromagnetic interference, and is more suitable for DC energy-consuming devices with multi-level output capabilities.
[0047] In the control method provided in the present application, the submodule capacitor is charged only during the switching process of the DC energy consumption device, and the thermal capacity required by the distributed resistor is greatly reduced. Therefore, the average charging power, total charging energy and discharge rate requirements of the submodule capacitor are greatly reduced, and the distributed resistor does not need to be equipped with cooling equipment, which further reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0048] In order to more clearly illustrate the technical solutions in the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative labor.
[0049] Figure 1 A schematic structural diagram of a DC energy consumption device in an embodiment of the present application;
[0050] Figure 2 A schematic structural diagram of a submodule in an embodiment of the present application;
[0051] Figure 3 A schematic flow chart of a control method in an embodiment of the present application;
[0052] Figure 4 A schematic diagram of the absorbed power of the DC energy consumption device in the embodiment of the present application;
[0053] Figure 5 Schematic diagram of DC bus voltage in an embodiment of the present application;
[0054] Figure 6A schematic diagram of the discharge voltage of the submodule capacitor in an embodiment of the present application;
[0055] Figure 7 Another schematic diagram of the absorbed power of the DC energy consumption device in the embodiment of the present application;
[0056] Figure 8 This is a schematic structural diagram of a control device in an embodiment of the present application. DETAILED DESCRIPTION
[0057] The technical solution in this application will be described below in conjunction with the accompanying drawings.
[0058] The terms "first", "second", etc. in the specification embodiments, claims, and drawings of the present application are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, including a series of steps or units. The method, system, product, or device is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.
[0059] It should be understood that in the present 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 objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers 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 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.
[0060] Embodiment 1:
[0061] The present application embodiment provides a control method for a DC energy consumption device. Figure 1 As shown, one end of the DC energy dissipation device 10 is connected to the positive DC bus DC+, and the other end of the DC energy dissipation device 10 is connected to the negative DC bus DC-. dc It is used to indicate the voltage difference between the positive DC bus DC+ and the negative DC bus DC-.
[0062] The DC energy consumption device 10 may include a plurality of submodules and a concentrated resistor R. The plurality of submodules include a submodule SM1, a submodule SM2, ..., a submodule SMn. The plurality of submodules are connected in series with the concentrated resistor R.
[0063] The specific structure of the submodule is introduced below by taking the submodule SM1 as an example.
[0064] like Figure 2 As shown, the submodule SM1 includes a first switch tube T1, a diode D, a submodule capacitor C, a second switch tube T2 and a distributed resistor r. In the embodiment of the present application, the first switch tube T1 and the second switch tube T2 can be insulated gate bipolar transistors (IGBT) with diodes connected in anti-parallel. Of course, the first switch tube T1 and the second switch tube T2 can also be other semiconductor devices, which are not limited in the embodiment of the present application.
[0065] The first electrode (which may be the source electrode) of the first switch tube T1 is connected to the anode electrode of the diode D, serving as the first end of the submodule SM1. The cathode of the diode D, the first electrode of the submodule capacitor C, and the first electrode (which may be the source electrode) of the second switch tube T2 are connected, the second electrode (which may be the drain electrode) of the second switch tube T2 is connected to the first end of the distributed resistor r, and the second electrode (which may be the source electrode) of the first switch tube T1, the second electrode of the submodule capacitor C, and the second end of the distributed resistor r are connected, serving as the second end of the submodule SM1.
[0066] It should be noted that, in addition to Figure 1 The DC energy consumption device shown, the control method provided in the present application can also be applied to other DC energy consumption devices with multi-level output capabilities, and the embodiments of the present application are not limited thereto.
[0067] like Figure 3 As shown, the control method 100 provided in the embodiment of the present application includes the following steps:
[0068] Step S1: Obtain DC bus voltage U dc .
[0069] Step S2: When the DC bus voltage U dc Higher than the starting threshold voltage of the DC energy consumption device (U ts When the DC energy consumption device is controlled, the submodules are put into operation in batches.
[0070] Step S3: When the DC bus voltage U dc Lower than the preset hysteresis lower limit voltage (U steady_ll When the control submodules are removed in batches.
[0071] In some embodiments, in step S2, when the DC bus voltage Udc Higher than the starting threshold voltage U of the DC energy consumption device ts When the DC energy consumption device is controlled, the submodules are put into operation in batches, including:
[0072] The DC energy consumption device is in the dead zone stage (i.e. Figure 4 T0~T1 in the figure), control the first switch tube T1 to turn off, refer to Figure 4 , the absorbed power of the DC energy consuming device (can be expressed as P chopper represents) gradually increases from 0 to the rated power of the DC energy consumption device (i.e. Figure 4 1.0pu in), refer to Figure 5 , DC bus voltage U dc From the start threshold voltage U ts Gradually increase to the maximum voltage of the DC bus (U max Indicates), then the DC bus voltage U dc Gradually decrease to the initial voltage of all sub-modules (which can be represented by U1).
[0073] Figure 4 In the figure, T0 is the start time of the DC energy consumption device, T1 is the start time of operation of all submodules, T2 is the start time of sequential removal of submodules, T3 is the removal time of all submodules, and T4 is the start time of sequential input of submodules in the next cycle.
[0074] Furthermore, after step S2, the control method provided in the embodiment of the present application further includes:
[0075] The DC energy consumption device is in the fully operational dead zone stage (i.e. Figure 4 The first switch tube T1 is controlled to be turned off, so that all sub-modules are put into operation, and the absorbed power P of the DC energy consumption device is chopper Maintain the rated power of the DC energy consumption device, DC bus voltage U dc The initial voltage U1 of all submodules is gradually reduced to the preset hysteresis lower limit voltage (which can be expressed as U steady_ll express).
[0076] In some other embodiments, when the DC bus voltage U dc Lower than the preset hysteresis lower limit voltage U steady_ll When the control submodules are removed in batches, they include:
[0077] The DC energy consumption device is in the dead zone removal stage (i.e. Figure 4 The first switch tube T1 is controlled to conduct, and the absorbed power P of the DC energy consumption device is choppe The rated power of the DC energy consumption device is gradually reduced to 0, and the DC bus voltage U dc From the preset hysteresis lower limit voltage Usteady_ll Gradually increase to the initial voltage at which all sub-modules are cut off (which can be represented by U2).
[0078] Furthermore, after step S3, the control method provided in the embodiment of the present application further includes:
[0079] The DC energy consumption device is in the stage of completely removing the dead zone (i.e. Figure 4 T3~T4 in the circuit) controls the first switch tube T1 to conduct, and the absorbed power P of the DC energy consumption device chopper Keep at 0, DC bus voltage U dc The initial voltage U2 cut off from all submodules gradually increases to the preset hysteresis upper limit voltage (which can be expressed as U steady_ul express).
[0080] It can be seen that the embodiment of the present application adopts hysteresis control of the DC bus voltage, that is, the DC bus voltage is controlled by controlling the absorbed power of the DC energy consuming device.
[0081] Optionally, the control method 100 provided in the embodiment of the present application may also use submodule capacitor voltage hysteresis control to realize the discharge of the submodule capacitor, and the specific process is as follows:
[0082] The first switch tube T1 and the second switch tube T2 are both turned off. Figure 6 As shown, the charging voltage of the submodule capacitor (can be expressed as U C Indicates) the reference voltage from the submodule capacitor (can be represented by U C_ref The charging voltage is gradually increased to the preset upper limit (U Cmax express).
[0083] The first switch tube T1 is turned off and the second switch tube T2 is turned on. The charging voltage U C From the preset charging voltage upper limit U Cmax Gradually reduce to the preset charging voltage lower limit (U Cmin express).
[0084] The first switch tube T1 and the second switch tube T2 are both turned off, and the charging voltage U C From the preset charging voltage lower limit U Cmin Gradually increase to the reference voltage U of the submodule capacitor C_ref .
[0085] Among them, the preset charging voltage upper limit U Cmax is the reference voltage U of the submodule capacitor C_ref The sum of the voltage fluctuation limit (which can be expressed as h) and the preset charging voltage lower limit U Cmin is the reference voltage U of the submodule capacitor C_refThe difference with the voltage fluctuation limit h. That is: U Cmax =U C_ref +h,U Cmin =U C_ref -h. Figure 6 In it, t represents the discharge time of the submodule capacitor, and ω represents the angular frequency of the flexible DC transmission system.
[0086] It can be seen that by controlling the first switch tube and the second switch tube, the discharge voltage of the submodule capacitor can be limited to U Cmin ~U Cmax within the range.
[0087] In the embodiment of the present application, when the receiving AC side fails, the output power of the receiving converter station is reduced or even lost, while the output power of the wind farm remains unchanged, resulting in power imbalance of the flexible DC transmission system and surplus power on the outgoing line, which will cause the DC bus voltage U dc If the DC bus voltage U dc The startup threshold voltage U is not reached ts , the DC energy consumption device does not start, and the capacitor of the flexible DC transmission system absorbs the surplus power. dc Reaching the start threshold voltage U ts , the DC energy consumption device starts and executes Figure 4 The four stages of the working cycle of the DC energy consumption device in the DC bus voltage U dc Range in U steady_ll ~U steady_ul Within the range, the DC bus voltage U dc of control, thereby achieving balanced dissipation of energy.
[0088] In order to balance the energy dissipation of the concentrated resistor R and the distributed resistor r, a modulation method such as pulse width is used to make the concentrated resistor R take on the main power absorption work. Set the absorption power P chopper The target power (0.5 pu) is modulated using the equal area rule to obtain Figure 7 Schematic diagram of the absorbed power shown.
[0089] It can be seen that in the embodiment of the present application, the gear change is completed by the sub-modules being put into operation or removed in batches. In order to reduce the current conversion rate of the transient process of the DC energy consuming device being put into operation, multiple steps are set. The accumulated absorbed energy of the sub-modules is calculated in real time during the process of being put into operation or removed. The sub-modules that absorb less energy are put into operation first, and the sub-modules that absorb more energy can be removed first.
[0090] Embodiment 2:
[0091] Based on the same inventive concept, the present application embodiment also provides a control device for a DC energy consumption device. For the relevant introduction of the DC energy consumption device and the submodule, please refer to the above. Figure 8 As shown, the control device 200 includes:
[0092] The acquisition module 21 is used to acquire the DC bus voltage.
[0093] The first control module 22 is used to control the submodules of the DC energy consumption device to be put into operation in batches when the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device.
[0094] The second control module 23 is used to control the submodules to be cut off in batches when the DC bus voltage is lower than a preset hysteresis lower limit voltage.
[0095] In a possible implementation, the first control module is specifically used for: the DC energy consumption device is in the dead zone stage (i.e. Figure 4 T0~T1 in the figure), control the first switch tube T1 to turn off, refer to Figure 4 , the absorbed power of the DC energy consuming device (can be expressed as P chopper represents) gradually increases from 0 to the rated power of the DC energy consumption device (i.e. Figure 4 1.0pu in), refer to Figure 5 , DC bus voltage U dc From the start threshold voltage U ts Gradually increase to the maximum voltage of the DC bus (U max Indicates), then the DC bus voltage U dc Gradually decrease to the initial voltage of all sub-modules (which can be represented by U1).
[0096] Furthermore, the first control module 22 is also used for: the DC energy consumption device is in the fully-input dead zone stage (i.e. Figure 4 The first switch tube T1 is controlled to be turned off, so that all sub-modules are put into operation, and the absorbed power P of the DC energy consumption device is chopper Maintain the rated power of the DC energy consumption device, DC bus voltage U dc The initial voltage U1 of all submodules is gradually reduced to the preset hysteresis lower limit voltage (which can be expressed as U steady_ll express).
[0097] In another possible implementation, the second control module 23 is specifically configured to: the DC energy consumption device is in the dead zone removal stage (i.e. Figure 4 The first switch tube T1 is controlled to conduct, and the absorbed power P of the DC energy consumption device is choppe The rated power of the DC energy consumption device is gradually reduced to 0, and the DC bus voltage U dcFrom the preset hysteresis lower limit voltage U steady_ll Gradually increase to the initial voltage at which all sub-modules are cut off (which can be represented by U2).
[0098] Furthermore, the first control module 22 is also used for: the DC energy consumption device is in the stage of completely removing the dead zone (ie Figure 4 The first switch tube T1 is controlled to conduct, and the absorbed power P of the DC energy consumption device chopper Keep at 0, DC bus voltage U dc The initial voltage cut off from all submodules is gradually increased to the preset hysteresis upper limit voltage (which can be expressed as U steady_ul express).
[0099] It can be seen that the embodiment of the present application adopts hysteresis control of the DC bus voltage, that is, the DC bus voltage is controlled by controlling the absorbed power of the DC energy consuming device.
[0100] Optionally, the control device 200 further includes a third control module, and the third control module is used to:
[0101] The first switch tube T1 and the second switch tube T2 are both turned off. Figure 6 As shown, the charging voltage of the submodule capacitor (can be expressed as U C Indicates) the reference voltage from the submodule capacitor (can be represented by U C_ref The charging voltage is gradually increased to the preset upper limit (U Cmax express).
[0102] The first switch tube T1 is turned off and the second switch tube T2 is turned on. The charging voltage U C From the preset charging voltage upper limit U Cmax Gradually reduce to the preset charging voltage lower limit (U Cmin express).
[0103] The first switch tube T1 and the second switch tube T2 are both turned off, and the charging voltage U C From the preset charging voltage lower limit U Cmin Gradually increase to the reference voltage U of the submodule capacitor C_ref .
[0104] Among them, the preset charging voltage upper limit U Cmax is the reference voltage U of the submodule capacitor C_ref The sum of the voltage fluctuation limit (which can be expressed as h) and the preset charging voltage lower limit U Cmin is the reference voltage U of the submodule capacitor C_ref The difference with the voltage fluctuation limit h. That is: U Cmax =U C_ref +h,UCmin =U C_ref -h. Figure 6 In it, t represents the discharge time of the submodule capacitor, and ω represents the angular frequency of the flexible DC transmission system.
[0105] It can be seen that by controlling the first switch tube and the second switch tube, the discharge voltage of the submodule capacitor can be limited to U Cmin ~U Cmax within the range.
[0106] Embodiment 3:
[0107] Based on the same inventive concept, the embodiment of the present application also provides a computer device, which includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute 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 (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, which are suitable for implementing one or more instructions, and are specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of the control method provided in the above embodiment.
[0108] Embodiment 4:
[0109] Based on the same inventive concept, the embodiment of the present application also provides a computer-readable storage medium, specifically a computer-readable storage medium (Memory), which 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 a built-in storage medium in a computer device and an extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). 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 memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the control method provided in the above embodiment.
[0110] Those skilled in the art will appreciate that the embodiments of the application may be provided as methods, systems, or computer program products. Therefore, the application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, 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 disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0111] 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 the 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 generate 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.
[0112] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 1A function specified in one or more boxes.
[0113] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.
[0114] 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 control method for a DC energy consumption device, characterized in that: include: Get the DC bus voltage; When the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device, controlling the submodules of the DC energy consumption device to be put into operation in batches; When the DC bus voltage is lower than a preset hysteresis lower limit voltage, the submodules are controlled to be cut off in batches.
2. The control method according to claim 1, characterized in that: One end of the DC energy dissipation device is connected to the positive DC bus, and the other end of the DC energy dissipation device is connected to the negative DC bus; the DC bus voltage is used to indicate the voltage difference between the positive DC bus and the negative DC bus; The DC energy consumption device comprises a plurality of submodules and a concentrated resistor; the plurality of submodules are connected in series in sequence and then connected in series with the concentrated resistor; The submodule includes a first switch tube, a diode, a submodule capacitor, a second switch tube and a distributed resistor; the first electrode of the first switch tube is connected to the anode of the diode as the first end of the submodule; the cathode of the diode, the first electrode of the submodule capacitor and the first electrode of the second switch tube are connected, the second electrode of the second switch tube is connected to the first end of the distributed resistor, and the second electrode of the first switch tube, the second electrode of the submodule capacitor and the second end of the distributed resistor are connected as the second end of the submodule.
3. The control method according to claim 2, characterized in that: When the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device, controlling the submodules of the DC energy consumption device to be put into use in batches includes: The first switch tube is controlled to be turned off, the absorbed power of the DC energy consumption device gradually increases from 0 to the rated power of the DC energy consumption device, the DC bus voltage gradually increases from the starting threshold voltage to the maximum voltage of the DC bus, and then the DC bus voltage gradually decreases to the initial voltage of all sub-modules.
4. The control method according to claim 2, characterized in that: When the DC bus voltage is lower than a preset hysteresis lower limit voltage, controlling the submodules to be removed in batches comprises: The first switch tube is controlled to be turned on, the absorbed power of the DC energy consumption device is gradually reduced from the rated power of the DC energy consumption device to 0, and the DC bus voltage is gradually increased from the preset hysteresis lower limit voltage to the initial voltage at which all sub-modules are cut off.
5. The control method according to claim 3, characterized in that: When the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device, after controlling the submodules of the DC energy consumption device to be put into use in batches, the control method further includes: The first switch tube is controlled to be turned off so that all submodules are put into operation, the absorbed power of the DC energy consumption device is maintained at the rated power of the DC energy consumption device, and the DC bus voltage is reduced from the initial voltage when all submodules are put into operation to the preset hysteresis lower limit voltage.
6. The control method according to claim 4, characterized in that: When the DC bus voltage is lower than the preset hysteresis lower limit voltage, after controlling the submodules to be removed in batches, the control method further includes: The first switch tube is controlled to be turned on, the absorbed power of the DC energy consumption device is maintained at 0, and the DC bus voltage gradually increases from the initial voltage after all sub-modules are cut off to the preset hysteresis upper limit voltage.
7. The control method according to claim 2, characterized in that: The control method further comprises: Controlling the first switch tube and the second switch tube to be turned off, so that the charging voltage of the submodule capacitor gradually increases from the reference voltage of the submodule capacitor to a preset upper limit of the charging voltage; Controlling the first switch tube to be turned off and controlling the second switch tube to be turned on, so that the charging voltage of the submodule capacitor gradually decreases from the preset charging voltage upper limit to the preset charging voltage lower limit; Controlling the first switch tube and the second switch tube to be turned off, so that the charging voltage of the submodule capacitor gradually increases from the preset charging voltage lower limit to the reference voltage of the submodule capacitor; The preset upper limit of the charging voltage is the sum of the reference voltage of the submodule capacitor and the voltage fluctuation limit, and the preset lower limit of the charging voltage is the difference between the reference voltage of the submodule capacitor and the voltage fluctuation limit.
8. A control device for a DC energy consumption device, characterized in that: include: An acquisition module, used for acquiring a DC bus voltage; A first control module, used for controlling the submodules of the DC energy consumption device to be put into operation in batches when the DC bus voltage is higher than the starting threshold voltage of the DC energy consumption device; The second control module is used to control the submodules to be cut off in batches when the DC bus voltage is lower than a preset hysteresis lower limit voltage.
9. The control device according to claim 8, characterized in that: One end of the DC energy dissipation device is connected to the positive DC bus, and the other end of the DC energy dissipation device is connected to the negative DC bus; the DC bus voltage is used to indicate the voltage difference between the positive DC bus and the negative DC bus; The DC energy consumption device comprises a plurality of submodules and a concentrated resistor; the plurality of submodules are connected in series in sequence and then connected in series with the concentrated resistor; The submodule includes a first switch tube, a diode, a submodule capacitor, a second switch tube and a distributed resistor; the first electrode of the first switch tube is connected to the anode of the diode as the first end of the submodule; the cathode of the diode, the first electrode of the submodule capacitor and the first electrode of the second switch tube are connected, the second electrode of the second switch tube is connected to the first end of the distributed resistor, and the second electrode of the first switch tube, the second electrode of the submodule capacitor and the second end of the distributed resistor are connected as the second end of the submodule.
10. The control device according to claim 9, characterized in that: The first control module is specifically used for: The first switch tube is controlled to be turned off, the absorbed power of the DC energy consumption device gradually increases from 0 to the rated power of the DC energy consumption device, the DC bus voltage gradually increases from the starting threshold voltage to the maximum voltage of the DC bus, and then the DC bus voltage gradually decreases to the initial voltage of all sub-modules.
11. The control device according to claim 9, characterized in that: The second control module is specifically used for: The first switch tube is controlled to be turned on, the absorbed power of the DC energy consumption device is gradually reduced from the rated power of the DC energy consumption device to 0, and the DC bus voltage is gradually increased from the preset hysteresis lower limit voltage to the initial voltage at which all sub-modules are cut off.
12. The control device according to claim 10, characterized in that: The first control module is also used for: The first switch tube is controlled to be turned off so that all submodules are put into operation, the absorbed power of the DC energy consumption device is maintained at the rated power of the DC energy consumption device, and the DC bus voltage is reduced from the initial voltage when all submodules are put into operation to the preset hysteresis lower limit voltage.
13. The control device according to claim 11, characterized in that: The second control module is also used for: The first switch tube is controlled to be turned on, the absorbed power of the DC energy consumption device is maintained at 0, and the DC bus voltage gradually increases from the initial voltage after all sub-modules are cut off to the preset hysteresis upper limit voltage.
14. The control device according to claim 9, characterized in that: The control device further includes a third control module, and the third control module is used for: Controlling the first switch tube and the second switch tube to be turned off, so that the charging voltage of the submodule capacitor gradually increases from the reference voltage of the submodule capacitor to a preset upper limit of the charging voltage; Controlling the first switch tube to be turned off and controlling the second switch tube to be turned on, so that the charging voltage of the submodule capacitor gradually decreases from the preset charging voltage upper limit to the preset charging voltage lower limit; Controlling the first switch tube and the second switch tube to be turned off, so that the charging voltage of the submodule capacitor gradually increases from the preset charging voltage lower limit to the reference voltage of the submodule capacitor; The preset upper limit of the charging voltage is the sum of the reference voltage of the submodule capacitor and the voltage fluctuation limit, and the preset lower limit of the charging voltage is the difference between the reference voltage of the submodule capacitor and the voltage fluctuation limit.
15. A computer device, characterized in that: include: one or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, the control method according to any one of claims 1 to 7 is implemented.
16. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the control method according to any one of claims 1 to 7 is implemented.