Power estimation method and system for turn-off current source converter

Abstract

The invention provides a power estimation method and system for a turn-off current source converter, and the method comprises the steps: obtaining a forced commutation angle through the derivation of a trigger angle and a natural commutation angle in a commutation process; based on the forced commutation angle, the AC secondary side voltage and the commutation transformer impedance, obtaining the current of each time period in the commutation process; and on the basis of the current value, using an approximate linearization processing method, and adopting Fourier analysis to obtain the power of the current source converter capable of being turned off. According to the method, the direct current voltage and the alternating current are obtained by analyzing different stages of the commutation process, the fundamental frequency active current and the fundamental frequency reactive current are obtained by utilizing an approximate linearization processing method and adopting Fourier analysis, estimation is more accurate, the accuracy of the control process is improved, the reactive supporting capacity of the current converter is accurately quantified, and a theoretical basis is provided for developing BPA software.

Description

Technical Field

[0001] The present invention relates to the field of converters, and particularly to a power estimation method and system for a turn-off current source converter. Background Art

[0002] The turn-off current source converter, as a new type of high-voltage DC conversion equipment, inherits the advantages of the traditional commutation converter (LCC) in terms of transmission capacity, loss, and economy. By realizing the controllable turn-off of the converter bridge arm, it fundamentally eliminates the risk of commutation failure and provides a better technical path for long-distance and large-capacity DC power transmission.

[0003] Figure 1 The following shows several common topologies of the turn-off current source converter. In the CLCC topology, each bridge arm is transformed into a new hybrid valve, which is composed of a main branch and an auxiliary branch in parallel. Both the main branch and the auxiliary branch are composed of thyristors and fully controlled IGBTs in series. When a system fault occurs, the IGBT in the auxiliary branch is turned off in advance to realize the action of the arrester and ensure the forced commutation process; in the IGCT topology, each bridge arm uses a single reverse-blocking IGCT device in multiple series. During normal system commutation, the bridge arm device realizes low-stress turn-off at the end of commutation. When a system fault occurs, after detecting the risk of commutation failure, the IGCT realizes active turn-off, and the arrester action ensures the forced transfer of current. Different from traditional DC power transmission, the MOV accelerating the commutation process and its operating voltage will affect the active and reactive power of the system. Therefore, in-depth study of the transient analytical formula of the turn-off current source converter is of great significance for promoting the development and application of this topology technology. This not only helps to optimize system design but also improves the reliability of the DC power transmission system during design.

[0004] The planning, design, and operation analysis of large power grids rely on software such as BPA for electromechanical transient simulation. At present, there is a lack of analytical expressions in the simulation process of the turn-off current source converter model, resulting in a lack of theoretical basis when developing BPA software and being unable to quantify the support ability of the converter during transients. Summary of the Invention

[0005] In order to solve the problem that the existing technology lacks analytical expressions in the simulation process of the turn-off current source converter model, resulting in a lack of theoretical basis when developing BPA software and being unable to quantify the support ability of the converter during transients, the present invention proposes a power estimation method for a turn-off current source converter, including:

[0006] During the commutation process, the forced commutation angle is obtained by deriving the firing angle and the natural commutation angle;

[0007] Based on the forced commutation angle, the AC secondary side voltage, and the converter transformer impedance, the current in each period during the commutation process is obtained;

[0008] Using the approximate linearization method based on the current value, the power of the turn-off current source converter is obtained by Fourier analysis.

[0009] Optionally, the method of using the approximate linearization method based on the current value and obtaining the power of the turn-off current source converter by Fourier analysis includes:

[0010] Decompose the phase voltage into active and reactive components based on the fundamental component of the current value;

[0011] Based on the active and reactive components, obtain the active power and reactive power input from the turn-off current source converter to the receiving-end AC system.

[0012] Optionally, the active component is calculated according to the following formula:

[0013]

[0014] The reactive component is calculated according to the following formula:

[0015]

[0016] In the formula, I (1)y is the active component, I (1) is the fundamental component of the line current on the AC side of the converter bridge, is the fundamental power factor angle of the converter, E is the AC secondary side voltage, α is the firing angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, U ar is the operating voltage of the arrester, X L is the impedance of the converter transformer, I (1)w is the reactive component.

[0017] Optionally, the active power is calculated according to the following formula:

[0018]

[0019] Among them, P CLCC is the active power;

[0020] The reactive power is calculated according to the following formula:

[0021]

[0022] In the formula, Q CLCC is the reactive power.

[0023] Optionally, the forced commutation angle is calculated according to the following formula:

[0024]

[0025] Wherein, E is the AC secondary side voltage, α is the firing angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, U ar is the arrester operating voltage, X L is the commutation transformer impedance, I d is the DC current.

[0026] Optionally, obtaining the currents in each period during the commutation process based on the forced commutation angle, the AC secondary side voltage, and the commutation transformer impedance includes:

[0027] Using Fourier analysis based on the forced commutation angle, the AC secondary side voltage, and the commutation transformer impedance to obtain the current of the valve in the rising stage of the natural commutation process and the current value of the valve when the arrester operates during the forced commutation operation process.

[0028] Optionally, the current of the valve in the rising stage of the natural commutation process is calculated according to the following formula:

[0029]

[0030] Wherein, i s1 is the current of the valve in the rising stage of the natural commutation process, E is the AC secondary side voltage, α is the firing angle, X L is the commutation transformer impedance, ω is the angular velocity, and t is the time;

[0031] The current value of the valve when the arrester operates during the forced commutation operation process is calculated according to the following formula:

[0032]

[0033] Wherein, i s2 is the current value of the valve when the arrester operates during the forced commutation operation process, U ar is the arrester operating voltage, μ 1 is the natural commutation angle.

[0034] Optionally, it further includes: obtaining the DC voltage based on the forced commutation angle in combination with the firing angle, the natural commutation angle, the arrester operating voltage, and the AC secondary side voltage.

[0035] Optionally, the DC voltage is calculated according to the following formula:

[0036]

[0037] Wherein, E is the AC secondary side voltage, α is the firing angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, U ar is the arrester operating voltage.

[0038] On the other hand, the present application also provides a power estimation system for a turn-off current source converter, including:

[0039] An angle derivation module, configured to derive the forced commutation angle through the triggering angle and the natural commutation angle during the commutation process;

[0040] A commutation calculation module, configured to obtain the current in each period during the commutation process based on the forced commutation angle, the AC secondary side voltage, and the commutation transformer impedance;

[0041] A power calculation module, configured to obtain the power of the turn-off current source converter by using the approximate linearization processing method based on the current value and adopting Fourier analysis.

[0042] Optionally, the power calculation module is specifically configured to:

[0043] Decompose the phase voltage into active and reactive components based on the fundamental component of the current value;

[0044] Obtain the active power and reactive power input from the turn-off current source converter to the receiving-end AC system based on the active and reactive components.

[0045] Optionally, the active component is calculated according to the following formula:

[0046]

[0047] The reactive component is calculated according to the following formula:

[0048]

[0049] In the formula, I (1)y is the active component, I (1) is the fundamental component of the line current on the AC side of the commutation bridge, is the fundamental power factor angle of the converter, E is the AC secondary side voltage, α is the triggering angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, U ar is the action voltage of the arrester, X L is the commutation transformer impedance, I (1)w is the reactive component.

[0050] Optionally, the active power is calculated according to the following formula:

[0051]

[0052] Among them, P CLCC is the active power;

[0053] The reactive power is calculated according to the following formula:

[0054]

[0055] Wherein, Q CLCC is the reactive power.

[0056] Optionally, the angle derivation module calculates the forced commutation angle through the following formula:

[0057]

[0058] Wherein, E is the AC secondary side voltage, α is the firing angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, U ar is the arrester operating voltage, X L is the converter transformer impedance, I d is the DC current.

[0059] Optionally, the commutation calculation module is specifically configured to:

[0060] Using Fourier analysis based on the forced commutation angle, AC secondary side voltage, and converter transformer impedance, obtain the valve current during the rising stage of the natural commutation process and the valve current value when the arrester operates during the forced commutation operation process.

[0061] Optionally, the valve current during the rising stage of the natural commutation process is calculated according to the following formula:

[0062]

[0063] Wherein, i s1 is the valve current during the rising stage of the natural commutation process, E is the AC secondary side voltage, α is the firing angle, X L is the converter transformer impedance, ω is the angular velocity, and t is the time;

[0064] The valve current value when the arrester operates during the forced commutation operation process is calculated according to the following formula:

[0065]

[0066] Wherein, i s2 is the valve current value when the arrester operates during the forced commutation operation process, U ar is the arrester operating voltage, μ 1 is the natural commutation angle.

[0067] Optionally, it further includes: a voltage calculation module, configured to obtain the DC voltage based on the forced commutation angle in combination with the firing angle, natural commutation angle, arrester operating voltage, and AC secondary side voltage.

[0068] Optionally, the DC voltage is calculated according to the following formula:

[0069]

[0070] In the formula, E is the AC secondary side voltage, α is the firing angle, and μ 1 is the natural commutation angle, and μ 2 is the forced commutation angle, and U ar is the arrester operating voltage.

[0071] On the other hand, the present application also provides an electronic device, including: at least one processor and a memory; the memory and the processor are connected by a bus;

[0072] The memory is used to store one or more programs;

[0073] When the one or more programs are executed by the at least one processor, a power estimation method of a turn-off current source converter as described above is implemented.

[0074] On the other hand, the present application also provides a readable storage medium, on which an execution program is stored, and when the execution program is executed, a power estimation method of a turn-off current source converter as described above is implemented.

[0075] Compared with the prior art, the beneficial effects of the present invention are:

[0076] The present invention provides a power estimation method for a turn-off current source converter, including: deriving the forced commutation angle through the firing angle and the natural commutation angle during the commutation process; obtaining the current in each period during the commutation process based on the forced commutation angle, the AC secondary side voltage, and the commutation transformer impedance; and obtaining the power of the turn-off current source converter by using the approximate linearization processing method and Fourier analysis based on the current value. By analyzing different stages of the commutation process, the present invention obtains the DC voltage and the AC current, and at the same time uses the approximate linearization processing method and Fourier analysis to obtain the fundamental frequency active and reactive currents, with more accurate estimation, improved accuracy of the control process, and precise quantification of the reactive power support ability of the converter, providing a theoretical basis for the development of BPA software. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 It is a schematic diagram of the turn-off current source converter valve of the present invention;

[0078] Figure 2 It is a flowchart of a power estimation method for a turn-off current source converter of the present invention;

[0079] Figure 3 It is a schematic diagram of the trigger timing of the present invention;

[0080] Figure 4 It is a waveform diagram of the AC side current of the present invention;

[0081] Figure 5Power characteristic curve of the present invention;

[0082] Figure 6 Reactive power comparison chart of the present invention;

[0083] Figure 7 Schematic diagram of the structure of an electronic device of the present invention. Detailed implementation manners

[0084] The present application proposes a power estimation method for a turn-off current source converter. The analytical expression of the turn-off current source converter proposed in this method fully considers the MOV action timing. By analyzing different stages of the commutation process, the DC voltage and AC current are obtained. At the same time, using the approximate linearization processing method, the fundamental frequency active and reactive currents are obtained by Fourier analysis. Finally, the active and reactive power analytical expressions are calculated. These analytical expressions have high accuracy and can be directly applied to the development of simulation software. These active and reactive power analytical expressions can calculate the power transmitted to the system and quantify the support ability of the converter during transients.

[0085] To better understand the present invention, the content of the present invention will be further described below in conjunction with the specification drawings and embodiments.

[0086] Embodiment 1:

[0087] A power estimation method for a turn-off current source converter, as Figure 2 shown, includes:

[0088] Step 1: Derive the forced commutation angle through the trigger angle and natural commutation angle during the commutation process;

[0089] Step 2: Based on the forced commutation angle, the AC secondary side voltage, and the commutation transformer impedance, obtain the current in each period during the commutation process;

[0090] Step 3: Based on the current value, use the approximate linearization processing method and adopt Fourier analysis to obtain the power of the turn-off current source converter.

[0091] The present application mainly derives the transient system characteristics of the turn-off current source converter and considers the overall arrester action, which has practical application value.

[0092] Step 1: Derive the forced commutation angle through the trigger angle and natural commutation angle during the commutation process, specifically including:

[0093] During a three-phase fault, after a certain delay of natural commutation, the forced commutation process is started. At this time, the arrester operates, and the specific trigger timing is as follows Figure 3 shown.

[0094] It can be analyzed from the commutation process that during the commutation process, the forced commutation angle can be obtained through the trigger angle α and the natural commutation angle μ 1Derive the forced commutation angle μ 2 , and the specific expression is as follows:

[0095]

[0096] where I d is the DC current; E is the AC secondary side voltage; X L is the converter transformer impedance; U ar is the arrester operating voltage.

[0097] Since this equation is a transcendental equation and is difficult to solve in engineering applications, and in actual engineering applications, the forced commutation angle μ 2 is very small, so the above formula can be approximately equivalent

[0098]

[0099] The AC side current of the turn-off current source type converter can be divided into the following six stages: (1) non-conduction stage (2) natural commutation rising stage (3) forced commutation rising stage (4) non-commutation conduction stage (5) natural commutation falling stage (6) forced commutation falling stage, and the corresponding current waveforms are as follows Figure 4 shown.

[0100] Step 2: Based on the forced commutation angle, AC secondary side voltage and converter transformer impedance, obtain the current in each period during the commutation process, including:

[0101] Using Fourier analysis based on the forced commutation angle, AC secondary side voltage and converter transformer impedance, obtain the valve current in the rising stage of the natural commutation process and the valve current value when the arrester operates during the forced commutation operation process.

[0102] Furthermore, the valve current in the rising stage of the natural commutation process is calculated according to the following formula:

[0103]

[0104] In the formula, i s1 is the valve current in the rising stage of the natural commutation process, E is the AC secondary side voltage, α is the trigger angle, X L is the converter transformer impedance, ω is the angular velocity, and t is the time;

[0105] The valve current value when the arrester operates during the forced commutation operation process is calculated according to the following formula:

[0106]

[0107] In the formula, i s2 is the valve current value when the arrester operates during the forced commutation operation process, U ar is the arrester operating voltage, μ1 is the natural commutation angle.

[0108] The specific implementation steps of Step 2 are as follows:

[0109] The turn-off current source converter topology is similar to that of the LCC, both having six valves. Here, taking the commutation from valve 5 to valve 1 as an example to derive the formula, for the commutation analysis from valve V5 to valve V1, during the rising stage of natural commutation, the current of valve V1 is:

[0110]

[0111] During the forced commutation operation, when the arrester operates, the current of valve V1 is:

[0112]

[0113] Similarly, the AC side currents in other time periods can be obtained.

[0114] Step 3: Based on the current value, using the approximate linearization processing method, the power of the turn-off current source converter is obtained by Fourier analysis, including:

[0115] Decompose the phase voltage into active and reactive components based on the fundamental component of the current value;

[0116] Based on the active and reactive components, obtain the active power and reactive power input from the turn-off current source converter to the receiving-end AC system.

[0117] Optionally, the active component is calculated according to the following formula:

[0118]

[0119] The reactive component is calculated according to the following formula:

[0120]

[0121] In the formula, I (1)y is the active component, I (1) is the fundamental component of the line current on the AC side of the converter bridge, is the fundamental power factor angle of the converter, E is the AC secondary side voltage, α is the trigger angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, U ar is the arrester operating voltage, X L is the converter transformer impedance, I (1)w is the reactive component.

[0122] Optionally, the active power is calculated according to the following formula:

[0123]

[0124] Among them, P CLCC is the active power;

[0125] The reactive power is calculated according to the following formula:

[0126]

[0127] In the formula, Q CLCC is the reactive power.

[0128] The specific implementation steps of step 3 include:

[0129] Finally, the fundamental component of the AC-side current is decomposed into the active component I (1)y as:

[0130]

[0131] The reactive component I (1)w The expression is:

[0132]

[0133] Then the active power P input from the current-source converter to the receiving AC system can be turned off CLCC as:

[0134]

[0135] Similarly, the reactive power Q CLCC is:

[0136]

[0137] In the formula, I (1) is the fundamental component of the line current on the AC side of the converter bridge, is the fundamental power factor angle of the converter. When calculating the active and reactive power of the converter, the traditional method is to approximately estimate the power factor angle by comparing the AC current waveform and the phase voltage waveform and thus calculate the active and reactive powers. This estimation method is relatively accurate when applied to LCC commutation, but for the current-source converter with forced commutation, that is, there is an impact of the arrester on the commutation process, the traditional estimation method is not applicable.

[0138] Through the calculation formulas of active power and reactive power, the power characteristic curves under different trigger angles can be obtained during AC voltage dips, as follows Figure 5 shown, it can provide reactive power support for the AC system when the trigger angle is around 170°.

[0139] The reactive powers obtained by calculating the forced commutation angle in two ways are as follows Figure 6As shown, it can be seen from the following figure that the error of the approximate estimation method is small within the operating range of the turn-off current source converter, thus verifying the feasibility of the forced commutation angle calculation formula.

[0140] When analyzing the DC voltage of the turn-off current source converter during the commutation process, the action voltage of the arrester needs to be considered. By analyzing the voltage in each period, the DC voltage U is derived. dc It is:

[0141]

[0142] In the formula, E is the secondary side AC voltage, α is the firing angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, and U ar is the action voltage of the arrester.

[0143] Based on the forced commutation angle calculated by the forced commutation angle calculation formula of the present invention, combined with the firing angle, natural commutation angle, action voltage of the arrester, and secondary side AC voltage, the DC voltage is derived to solve the problem that the design of the relevant control strategy of the turn-off current source converter lacks a theoretical basis.

[0144] A power estimation method for a turn-off current source converter provided by the present invention accurately analyzes the commutation process in each period and obtains the converter power through the fundamental current, which is more accurate than the traditional estimation method. Analyzing the transient DC voltage of the turn-off current source converter improves the accuracy of the control process. Through linearization processing, the forced commutation angle can be obtained more intuitively on the premise of ensuring the accuracy of the analytical formula; the analyzed transient power characteristics can accurately quantify the reactive power support ability of the converter.

[0145] Embodiment 2:

[0146] Based on the same inventive concept, the present invention also provides a power estimation system for a turn-off current source converter, including:

[0147] An angle derivation module for deriving the forced commutation angle through the firing angle and natural commutation angle during the commutation process;

[0148] A commutation calculation module for obtaining the current in each period during the commutation process based on the forced commutation angle, secondary side AC voltage, and converter transformer impedance;

[0149] A power calculation module for obtaining the power of the turn-off current source converter by using the Fourier analysis with the approximate linearization processing method based on the current value.

[0150] Optionally, the power calculation module is specifically used for:

[0151] Decomposing the phase voltage into active and reactive components based on the fundamental component of the current value;

[0152] Based on the active component and the reactive component, the active power and the reactive power input from the turn-off current source converter to the receiving-end AC system are obtained.

[0153] Optionally, the active component is calculated according to the following formula:

[0154]

[0155] The reactive component is calculated according to the following formula:

[0156]

[0157] In the formula, I (1)y is the active component, I (1) is the fundamental component of the line current on the AC side of the converter bridge, is the fundamental power factor angle of the converter, E is the AC secondary side voltage, α is the firing angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, U ar is the operating voltage of the arrester, X L is the impedance of the converter transformer, I (1)w is the reactive component.

[0158] Optionally, the active power is calculated according to the following formula:

[0159]

[0160] where, P CLCC is the active power;

[0161] The reactive power is calculated according to the following formula:

[0162]

[0163] In the formula, Q CLCC is the reactive power.

[0164] Optionally, the angle derivation module calculates the forced commutation angle through the following formula:

[0165]

[0166] In the formula, E is the AC secondary side voltage, α is the firing angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, U ar is the operating voltage of the arrester, X L is the impedance of the converter transformer, I d is the DC current.

[0167] Optionally, the commutation calculation module is specifically configured to:

[0168] Using Fourier analysis based on the forced commutation angle, the AC secondary side voltage, and the converter transformer impedance, the current of the valve during the rising stage of the natural commutation process and the current value of the valve when the arrester operates during the forced commutation operation process are obtained.

[0169] Optionally, the current of the valve during the rising stage of the natural commutation process is calculated according to the following formula:

[0170]

[0171] In the formula, i s1 is the current of the valve during the rising stage of the natural commutation process, E is the AC secondary side voltage, α is the trigger angle, X L is the converter transformer impedance, ω is the angular velocity, and t is the time;

[0172] The current value of the valve when the arrester operates during the forced commutation operation process is calculated according to the following formula:

[0173]

[0174] In the formula, i s2 is the current value of the valve when the arrester operates during the forced commutation operation process, U ar is the operating voltage of the arrester, and μ 1 is the natural commutation angle.

[0175] Optionally, it further includes: a voltage calculation module, configured to obtain a DC voltage based on the forced commutation angle in combination with the trigger angle, the natural commutation angle, the operating voltage of the arrester, and the AC secondary side voltage.

[0176] Optionally, the DC voltage is calculated according to the following formula:

[0177]

[0178] In the formula, E is the AC secondary side voltage, α is the trigger angle, μ 1 is the natural commutation angle, μ 2 is the forced commutation angle, and U ar is the operating voltage of the arrester.

[0179] Embodiment 3

[0180] As Figure 7 shown, the present invention further provides an electronic device, which may be a computer device, a single-chip microcomputer device, an intelligent mobile device, etc. The electronic device in this embodiment may include a processor, a memory, a transceiver component, etc. The memory, the processor, and the transceiver component are connected by a bus; the memory can be used to store an execution program, and an exemplary execution program may include instructions; the processor is used to execute the instructions stored in the memory. The memory can also be used to store data, and the data can be called and / or modified when the instructions are executed.

[0181] The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of a power estimation method for a turn-off current source converter in the above embodiments.

[0182] Embodiment 4

[0183] Based on the same inventive concept, the present invention also provides a readable storage medium, specifically an electronic device-readable storage medium (Memory). The electronic device-readable storage medium is a memory device in the electronic device, used to store programs and data. It can be understood that the storage medium here can include both the built-in storage medium in the electronic device and, of course, the extended storage medium supported by the electronic device. The storage medium provides a storage space, and this storage space stores the operating system of the terminal. And, one or more instructions suitable for being loaded and executed by the processor are also stored in this storage space. These instructions can be one or more execution programs (including program codes). It should be noted that the storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. By the processor loading and executing one or more instructions stored in the storage medium, the steps of a power estimation method for a turn-off current source converter in the above embodiments can be implemented.

[0184] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0185] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device generate means for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or means for implementing the functions specified in multiple blocks.

[0186] These computer program instructions can 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, such that the instructions stored in the computer-readable memory produce a manufacture including instruction means that implement the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or means for implementing the functions specified in multiple blocks.

[0187] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or means for implementing the functions specified in multiple blocks.

[0188] The above are only embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A method for estimating power of a switchable current source converter, characterized in that: include: In the commutation process, the forced commutation angle is derived by the trigger angle and the natural commutation angle; Based on the forced commutation angle, AC secondary voltage and commutation impedance, the current in each period of the commutation process is obtained; Based on the current value, an approximate linearization processing method is used to obtain the power of the switchable current source converter by Fourier analysis.

2. The method according to claim 1, characterized in that The method of obtaining the power of the switchable current source converter by using an approximate linearization processing method based on the current value and adopting Fourier analysis includes: Decomposing the phase voltage into active component and reactive component based on the fundamental component of the current value; Based on the active component and the reactive component, the active power and the reactive power inputted by the turn-off current source converter to the receiving-end AC system are obtained.

3. The method according to claim 2, characterized in that The active component is calculated as follows: The reactive component is calculated as follows: In the formula, I (1)y is the active component, I (1) is the fundamental component of the AC side line current of the converter bridge, is the fundamental power factor angle of the converter, E is the AC secondary voltage, α is the trigger angle, μ1 is the natural commutation angle, μ2 is the forced commutation angle, U ar is the arrester action voltage, X L is the commutation impedance, I (1)w is the reactive component.

4. The method according to claim 3, characterized in that The active power is calculated as follows: Among them, P CLCC is the active power; The reactive power is calculated as follows: In the formula, Q CLCC is the reactive power.

5. The method according to claim 1, characterized in that The forced commutation angle is calculated as follows: Where, E is the AC secondary voltage, α is the trigger angle, μ1 is the natural commutation angle, μ2 is the forced commutation angle, and U ar is the arrester action voltage, X L is the commutation impedance, I d is a direct current.

6. The method according to claim 1, characterized in that The current in each period of the commutation process is obtained based on the forced commutation angle, the AC secondary side voltage and the commutation impedance, including: Based on the forced commutation angle, AC secondary voltage and commutation impedance, Fourier analysis is used to obtain the valve current in the rising stage of the natural commutation process and the valve current value when the arrester is activated during the forced commutation operation.

7. The method according to claim 6, characterized in that The current of the valve in the rising stage of the natural commutation process is calculated as follows: In the formula, i s1 is the current of the valve in the rising stage of the natural commutation process, E is the AC secondary voltage, α is the trigger angle, and X L is the commutation impedance, ω is the angular velocity, and t is the time; During the forced commutation operation, when the arrester is actuated, the current value of the valve is calculated as follows: In the formula, i s2 is the current value of the valve when the arrester is actuated during forced commutation operation, U ar is the arrester action voltage, μ1 is the natural commutation angle.

8. A power estimation system for a switchable current source converter, characterized in that: include: An angle derivation module is used to derive the forced commutation angle through the trigger angle and the natural commutation angle during the commutation process; A commutation calculation module is used to obtain the current in each period of the commutation process based on the forced commutation angle, the AC secondary voltage and the commutation impedance; The power calculation module is used to obtain the power of the switchable current source converter by using an approximate linearization processing method based on the current value and adopting Fourier analysis.

9. An electronic device, characterized in that: include: at least one processor and memory; The memory and the processor are connected via a bus; The memory is used to store one or more programs; When the one or more programs are executed by the at least one processor, a power estimation method for a turn-off current source converter according to any one of claims 1 to 7 is implemented.

10. A readable storage medium, characterized in that: An execution program is stored thereon, and when the execution program is executed, a power estimation method for a switchable current source converter as claimed in any one of claims 1 to 7 is implemented.

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