Asymmetric triggering voltage reduction method and system for thyristor converter

Abstract

The present invention relates to an asymmetric triggering voltage reduction method and system for a thyristor converter, the method comprising: in the voltage reduction process on the rectifier side, controlling the thyristor triggering angle of the first half bridge and the thyristor triggering angle of the second half bridge of the three-phase thyristor converter to be unequal, so as to suppress the reactive power generated by the three-phase thyristor converter during voltage reduction. The present invention reduces the fundamental current by controlling the thyristor triggering angles of the first half bridge and the second half bridge of the three-phase thyristor converter to be different, thereby solving the problem of excessive reactive power generated by the conventional thyristor converter symmetrical triggering method during voltage reduction.

Description

Technical Field

[0001] The invention relates to the technical field of converter control, and in particular to an asymmetric triggering voltage reduction method for a thyristor converter. Background Art

[0002] Grid-commutated DC transmission technology (LCC) has a large number of applications in China. It uses thyristor converters as commutation tools, with strong transmission capacity, good stability, and high reliability, and plays an important role in long-distance energy transmission. Thyristor converters generally use the trigger angle as a control method to control the output DC voltage and thus adjust the current. When a DC line fails, the thyristor converter will increase the trigger angle when the fault occurs, reduce the DC voltage and thus reduce the DC current. When the DC line is prone to discharge due to local weather problems, the DC project will operate in a step-down state, that is, operate at a lower voltage than the normal operating voltage to reduce the occurrence of corona and prevent failures. When a DC line discharges, the trigger angle will quickly increase, causing a negative voltage to be generated on the DC side, eliminating the free electricity on the line and accelerating fault recovery.

[0003] When operating in step-down conditions, the reactive power consumed by the DC is greatly increased due to the increased trigger angle. At this time, if the AC system connected to it is weak, the AC voltage will be lowered, causing a chain reaction failure.

[0004] The traditional voltage reduction method of increasing the trigger angle is one of the reasons why the AC bus voltage decreases when the DC system fails, which causes the fault to be transmitted and expands the scope of the fault. Therefore, a method is needed to reduce the changes in reactive power consumption and active power consumption when a DC system fails, thereby reducing the impact on the AC system. Summary of the invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides an asymmetric triggering voltage reduction method and system for a thyristor converter, which can reduce the changes in reactive power consumption and active power consumption when a fault occurs in a DC system.

[0006] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a thyristor converter asymmetric triggering step-down method comprises:

[0007] During the voltage reduction process on the rectifier side, the thyristor triggering angle of the first half bridge and the thyristor triggering angle of the second half bridge of the three-phase thyristor converter are controlled to be unequal, so as to suppress the reactive power generated by the three-phase thyristor converter during voltage reduction.

[0008] Further, the three thyristors of the first half bridge are triggered at intervals of 120°, and the three thyristors of the second half bridge are triggered at intervals of 120°.

[0009] Furthermore, the method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal includes:

[0010] Increase the trigger angle of the first half bridge and the second half bridge;

[0011] When the trigger angle of the first half bridge is equal to the first preset value, the trigger angle of the first half bridge is controlled to remain unchanged, and the trigger angle of the second half bridge continues to increase.

[0012] Furthermore, the method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes:

[0013] Increase the trigger angle of the first half bridge and the second half bridge;

[0014] When the trigger angle of the first half bridge is equal to the second preset value, the trigger angle of the first half bridge is controlled to decrease, and the trigger angle of the second half bridge continues to increase.

[0015] Furthermore, the method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes:

[0016] Increase the trigger angle of the first half bridge and the second half bridge;

[0017] When the trigger angle of the first half bridge is equal to the third preset value, the trigger angle of the first half bridge is controlled to jump to the fourth preset value, and the trigger angle of the second half bridge is continuously increased;

[0018] The fourth preset value is smaller than the third preset value.

[0019] Furthermore, the method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes:

[0020] Controlling the trigger angle of the first half bridge to be fixed at a fifth preset value;

[0021] Controlling the trigger angle of the second half bridge to be fixed at a sixth preset value;

[0022] The fifth preset value and the sixth preset value are not equal.

[0023] In a second aspect, an asymmetric triggering step-down system for a thyristor converter is provided, comprising:

[0024] The processing unit is used to control the thyristor triggering angle of the first half bridge and the thyristor triggering angle of the second half bridge of the three-phase thyristor converter to be unequal during the voltage reduction process on the rectifier side, so as to suppress the reactive power generated by the three-phase thyristor converter during voltage reduction.

[0025] Further, the three thyristors of the first half bridge are triggered at intervals of 120°, and the three thyristors of the second half bridge are triggered at intervals of 120°.

[0026] According to a third aspect, a processing device is provided, comprising computer program instructions, wherein the computer program instructions are used to implement the steps corresponding to the asymmetric triggering step-down method of the thyristor converter when the processing device executes the computer program instructions.

[0027] In a fourth aspect, a computer-readable storage medium is provided, on which computer program instructions are stored, wherein the computer program instructions, when executed by a processor, are used to implement the steps corresponding to the asymmetric triggering step-down method of the above-mentioned thyristor converter.

[0028] The present invention adopts the above technical solution, and has the following advantages: the present invention controls the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal during the voltage reduction process on the rectifier side, so as to suppress the reactive power of the three-phase thyristor converter. The present invention controls the thyristor trigger angle of the first half bridge and the second half bridge of the three-phase thyristor converter to be different, thereby reducing the fundamental current, thereby solving the problem of excessive reactive power generated by the traditional thyristor converter symmetrical triggering method when the DC side is reduced.

[0029] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the background technology, the drawings required for use in the embodiments of the present invention or the background technology will be described below.

[0031] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and, together with the specification, are used to illustrate the technical solutions disclosed in the present invention.

[0032] Figure 1 A schematic diagram of a method flow chart provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the converter DC side voltage-converter DC side current of the first phase when the first half-bridge trigger angle is 45° and the second half-bridge trigger angle is 15° is provided for an embodiment of the present invention, wherein: Figure 2 (a) is the voltage on the DC side of the converter when the first half-bridge trigger angle is 45° and the second half-bridge trigger angle is 15°; Figure 2 (b) is the corresponding current waveform

[0034] Figure 3A schematic diagram of the converter DC side voltage and converter DC side current of the first phase when the first half-bridge trigger angle is 75° and the second half-bridge trigger angle is 15° is provided for an embodiment of the present invention, wherein: Figure 3 (a) is the voltage on the DC side of the converter when the first half-bridge trigger angle is 75° and the second half-bridge trigger angle is 15°, Figure 3 (b) is the corresponding current waveform;

[0035] Figure 4 A schematic diagram of the converter DC side voltage and converter DC side current of the first phase when the first half-bridge trigger angle is 105° and the second half-bridge trigger angle is 15° is provided for an embodiment of the present invention, wherein: Figure 4 (a) is the voltage on the DC side of the converter when the first half-bridge trigger angle is 105° and the second half-bridge trigger angle is 15°, Figure 4 (b) is the corresponding current waveform;

[0036] Figure 5 A schematic diagram of the converter DC side voltage and converter DC side current of the first phase when the first half-bridge trigger angle is 135° and the second half-bridge trigger angle is 15° is provided for an embodiment of the present invention, wherein: Figure 5 (a) is the voltage on the DC side of the converter when the first half-bridge trigger angle is 135° and the second half-bridge trigger angle is 15°, Figure 5 (b) is the corresponding current waveform;

[0037] Figure 6 A schematic diagram of a control flow of a symmetrical triggering voltage reduction method for a conventional thyristor converter provided by an embodiment of the present invention;

[0038] Figure 7 A schematic flow chart of a first control method based on asymmetric triggering voltage reduction of a thyristor converter provided in one embodiment of the present invention;

[0039] Figure 8 A schematic flow chart of a second control method for asymmetric triggering voltage reduction of a thyristor converter provided in one embodiment of the present invention;

[0040] Fig. 9 A schematic flow chart of a third control method for asymmetric triggering voltage reduction of a thyristor converter provided in one embodiment of the present invention;

[0041] Fig.10 A harmonic line graph of a conventional method and the present method provided in an embodiment of the present invention, wherein: Fig.10 (a) is the harmonic line chart of the traditional method. Fig.10 (b) is the harmonic line graph of this method;

[0042] Fig.11A schematic diagram of converter DC side voltage and converter DC side current of a symmetrical triggering step-down method for a conventional thyristor converter provided in an embodiment of the present invention, wherein: Fig.11 (a) is the triggering and commutation waveform of each thyristor; Fig.11 (b) is the current waveform of the first phase (solid line) and the AC voltage waveform of the first phase;

[0043] Fig.12 A schematic diagram of converter DC side voltage and converter DC side current during a step-down condition of a symmetrically triggered step-down method for a conventional thyristor converter provided in an embodiment of the present invention, wherein: Fig.12 (a) is the voltage waveform on the DC side of the converter. Fig.12 (b) is the current waveform of phase A and the AC voltage waveform of phase A. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0046] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0047] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0048] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0049] At present, the problem of excessive reactive power generated in the step-down process by the symmetrical triggering step-down method of the traditional thyristor converter exists. Therefore, the present invention aims to provide an asymmetrical triggering step-down method of a thyristor converter, the method comprising: in the step-down process on the rectifier side, controlling the thyristor triggering angle of the first half bridge and the thyristor triggering angle of the second half bridge of the three-phase thyristor converter to be unequal, so as to suppress the reactive power generated by the three-phase thyristor converter during the step-down process. The present invention solves the problem of excessive reactive power generated by the symmetrical triggering method of the traditional thyristor converter by controlling the thyristor triggering angles of the first half bridge and the second half bridge of the three-phase thyristor converter to be different, thereby reducing the fundamental current.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment provides an asymmetric triggering and voltage reduction method for a thyristor converter, comprising:

[0052] S100, during the voltage reduction process on the rectifier side, controlling the thyristor triggering angle of the first half bridge and the thyristor triggering angle of the second half bridge of the three-phase thyristor converter to be unequal, so as to suppress reactive power generated by the three-phase thyristor converter during voltage reduction.

[0053] It should be noted that when the first half-bridge is the upper half-bridge of the three-phase thyristor converter, the second half-bridge is the lower half-bridge of the three-phase thyristor converter; when the second half-bridge is the lower half-bridge of the three-phase thyristor converter, the second half-bridge is the upper half-bridge of the three-phase thyristor converter. Among them, the thyristor triggering angle of the first half-bridge and the thyristor triggering angle of the second half-bridge that control the three-phase thyristor converter are not equal, that is, the upper and lower thyristor triggering of the thyristor valve pair is no longer 180° apart. Based on the positive voltage triggering characteristics of the thyristor, it is feasible to realize that the triggering angle of the upper half-bridge and the triggering angle of the lower half-bridge of the three-phase thyristor converter are not equal.

[0054] like Fig.11As shown in FIG. 1 , in the conventional LCC control method, the trigger angles of all thyristors of the upper half bridge and the lower half bridge are the same, such as Fig.11 (a) shows the triggering and commutation waveforms of each thyristor when α = 15° and μ = 30°. The thin lines are the waveforms of each AC phase voltage, and the thick lines are the DC side voltage waveforms of the converter. After the voltage divider filtering of the smoothing reactor, the DC equivalent average value of the DC side voltage of the converter is the DC voltage. It can be seen that the DC side voltage of the converter has a great relationship with the trigger angle α. Fig.11 (b) shows the current waveform (solid line) of the first phase and the AC voltage waveform (dashed line) of the first phase when α=15° and μ=30°. It can be seen that the current of the first phase is composed of two trapezoidal waves in opposite directions. The positive trapezoidal wave starts when the upper thyristor of the first corresponding phase is triggered and ends when the upper thyristor of the second corresponding phase is triggered and the phase change is completed. The amplitude of the trapezoidal wave is the DC current. The oblique waist part of the trapezoidal wave is the current conversion process during phase change. The electrical angle corresponding to its time length is the phase change angle μ.

[0055] like Fig.12 As shown in FIG. 1 , when the LCC converter on the rectifier side needs to step down, the traditional LCC control will increase the trigger angle, such as Fig.12 (a) shows the voltage waveform of the DC side of the converter when α is 45° and μ is 30°. It can be seen that the DC side voltage of the converter is significantly reduced. Fig.12 (b) shows the current waveform of phase A and the AC voltage waveform of phase A when α=45° and μ=30°. It can be seen that when the voltage is reduced, the amplitude of the current trapezoidal wave remains unchanged and is still a DC current (assuming that the DC current can still be controlled to remain unchanged), but the phase angle difference between the current waveform and the voltage waveform increases significantly. In terms of power, the apparent power on the AC side remains unchanged at this time, but the active power decreases and the reactive power increases.

[0056] In this embodiment, the commutation angle of the upper half-bridge thyristor is set to μ up , the trigger angle of the upper half-bridge thyristor is α up , the commutation angle of the lower half-bridge thyristor is μ down , the trigger angle of the lower half-bridge thyristor is α down , to fix α down =15°, increasing α up For example, for the sake of simplicity, assume that the commutation angle μ of the upper half-bridge thyristor is up and the commutation angle μ of the lower half-bridge thyristor down Still equal, and assuming it is 15° (in reality it will be somewhat different, but not much), Figure 2 (a) is α up =45°, the voltage on the DC side of the converter is, Figure 2 (b) is the corresponding current waveform; Figure 3(a) is α up =75°, the voltage on the DC side of the converter is, Figure 3 (b) is the corresponding current waveform; Figure 4 (a)α up =105°, the voltage on the DC side of the converter is, Figure 4 (b) is the corresponding current waveform; Figure 5 (a)α up =135°, the voltage on the DC side of the converter is, Figure 5 (b) is the corresponding current waveform. Figure 2 , Figure 3 , Figure 4 and Figure 5 As can be seen in up The DC voltage of the converter decreases continuously, while the effective value of the AC current of the first phase decreases continuously, and the angle between the AC voltage and the DC voltage increases continuously. up and α down When the difference between the two is greater than 60°, the positive trapezoidal wave and the reverse trapezoidal wave of the AC side current overlap, indicating that the "conduction bypass pair" phenomenon occurs at this time, where the thyristors of the upper and lower half bridges of a certain phase are turned on at the same time. The DC current flows directly through the thyristor pair of a certain phase and no longer flows through the AC side. After that, the effective value of the current decreases significantly. Both the reactive and active values ​​on the AC side decrease.

[0057] A normalized LCC converter is used to compare the DC voltage, active power, and reactive power of the converter corresponding to different trigger angles under different step-down methods. Taking a typical LCC converter as an example, the power corresponding to each angle under unbalanced triggering is calculated. Assuming that the DC current does not change during the change of the trigger angle, for the convenience of analysis, it is assumed that the μ angle does not change (in real projects, there will be a change of about 10°, which will not significantly affect the DC voltage and AC current), μ up =μ down =15°. Then when α down =15°, α up The voltage on the DC side of the converter, the reactive power and active power on the AC side of the converter are shown in Table 1 below:

[0058] Table 1: α up The DC voltage of the converter, the reactive power and active power of the AC side of the converter are constantly changing.

[0059] <![CDATA[α up ]]> 15° 45° 75° 105° 135° DC voltage 1.5148 1.2559 0.8634 0.4428 0.1063 Reactive power 0.2105 0.3234 0.3777 0.3591 0.2725 Active Power 0.5079 0.4212 0.2897 0.1487 0.0358

[0060] α down and α up The DC side voltage, AC side reactive power and active power of the converter are shown in Table 2 below:

[0061] Table 2: α down and α up The DC side voltage, AC side reactive power and active power of the converter are obtained by synchronous change.

[0062] <![CDATA[α up / a down ]]> 15° 30° 45° 60° 75° DC voltage 1.5148 1.3003 0.9973 0.6262 0.2125 Reactive power 0.2105 0.3348 0.4363 0.5080 0.5451 Active Power 0.5079 0.4361 0.3346 0.2104 0.0717

[0063] It can be seen from Table 1 and Table 2 that when α is fixed down , increase α up When the reactive power of the converter increases, compared with the synchronous increase α down and α up , the total amount of reactive power increase is much smaller. Compared with the traditional method of increasing the trigger angle to reduce the DC voltage, the unbalanced trigger method directly reduces the total effective value of the AC side current, that is, the apparent power on the AC side is reduced.

[0064] Furthermore, if Fig.10 As shown, with α up =75°, α down = 15° as an example, considering the Y-connected and D-connected converters used in general converter stations, the harmonic components are as follows Fig.10 (a). In contrast, up =45°, α down =45° harmonic components such as Fig.10 As shown in (b), it can be seen that the asymmetrically triggered converter produces larger 2nd and 4th harmonics, as well as even harmonics such as 8th, 10th, 14th, and 16th. Compared with the odd harmonics generated by the traditional triggering method, they are less harmful to the AC system.

[0065] Preferably, the three thyristors of the first half bridge are triggered at intervals of 120°, and the three thyristors of the second half bridge are triggered at intervals of 120°.

[0066] Preferably, the method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal includes:

[0067] Increase the firing angles of the first half bridge and the second half bridge.

[0068] When the trigger angle of the first half bridge is equal to the first preset value, the trigger angle of the first half bridge is controlled to remain unchanged, and the trigger angle of the second half bridge continues to increase.

[0069] It should be noted that in traditional LCC converters, the trigger angle α at the sending end is generally used to control the DC current. Figure 6 , the measured DC current I d and DC current target value I * d The difference is subtracted and the trigger angle α is calculated by the controller (usually a PI controller).

[0070] In this embodiment, when a DC fault occurs, the trigger angles of the upper and lower bridges of the rectifier increase synchronously to reduce the DC voltage. down Set a maximum value α max (i.e. the first preset value), when α up and α down After increasing to this maximum value, α down Remaining at this maximum value, α up Continue to increase and enter the asymmetric trigger state; when the DC fault is restored, the controller on the rectifier side will trigger the angle α up and α down When pulling back, when α up Shrink to less than α max After that, α down Also synchronized from α max Zoom out, change back and alpha up Synchronize, the converter returns to normal working state. For specific control block diagram, refer to Figure 7 , α up and α down is symmetric, so give α up Setting a maximum value has the same effect.

[0071] Preferably, the method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes:

[0072] Increase the firing angles of the first half bridge and the second half bridge.

[0073] When the trigger angle of the first half bridge is equal to the second preset value, the trigger angle of the first half bridge is controlled to decrease, and the trigger angle of the second half bridge continues to increase.

[0074] In this embodiment, when a DC fault occurs, the trigger angles of the upper and lower bridges of the rectifier increase synchronously to reduce the DC voltage. down Set a maximum value α max , when α up and α down After increasing to this maximum value, α max , α down Increasing in the opposite direction, i.e. α down =α max -(α up -α max )=2×α max -α up , while α up Continue to increase and enter the asymmetric trigger state; when the DC fault is restored, the controller on the rectifier side pulls the trigger angle α back. u p is reduced to be equal to αmax When α down Also synchronized equal to α max , when α u p is reduced to less than α max When α down From α max The inverter is reduced synchronously and returns to normal working state. The specific control block diagram is as follows Fig. 9 As shown. up and α down is symmetric, so give α up Setting a maximum value has the same effect.

[0075] Preferably, the method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes:

[0076] Increase the firing angles of the first half bridge and the second half bridge.

[0077] When the trigger angle of the first half bridge is equal to the third preset value, the trigger angle of the first half bridge is controlled to jump to the fourth preset value, and the trigger angle of the second half bridge continues to increase, wherein the fourth preset value is less than the third preset value.

[0078] In this embodiment, when a DC fault occurs, the trigger angles of the upper and lower bridges of the rectifier increase synchronously to reduce the DC voltage. down Set a maximum value α max and jump value α set (fourth preset value), where α set Ratio α max When α up and α down After increasing to more than the maximum value, α max , α down Jump to α set And keep it, α up Continue to increase and enter the asymmetric trigger state; when the DC fault is restored, the controller on the rectifier side will trigger the angle α down and α up When pulling back, when α up Reduce to equal α max When α down From α set Jump to α max , when α up Shrink to less than α max When α down From α max Synchronously reduce, change back and alpha up Synchronize, and the converter returns to normal working state. For the specific control block diagram, see Figure 8 As shown. up and αdown is symmetric, so give α up Setting a maximum value and a jump value has the same effect.

[0079] Preferably, the method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes:

[0080] The trigger angle of the first half bridge is controlled to be fixed at a fifth preset value.

[0081] The trigger angle of the second half bridge is controlled to be fixed at a sixth preset value, wherein the fifth preset value is not equal to the sixth preset value.

[0082] In this embodiment, after the rectifier side receives a DC line fault signal or a voltage reduction operation signal from an operator, α down and let α up The voltage is fixed to certain two determined values ​​(a fifth preset value and a sixth preset value) to suppress reactive power generated by the three-phase thyristor converter when stepping down the voltage.

[0083] Example 2

[0084] This embodiment provides an asymmetric triggering step-down system for a thyristor converter, including:

[0085] The processing unit is used to control the thyristor triggering angle of the first half bridge and the thyristor triggering angle of the second half bridge of the three-phase thyristor converter to be unequal during the voltage reduction process on the rectifier side, so as to suppress the reactive power generated by the three-phase thyristor converter during voltage reduction.

[0086] The system provided in this embodiment is used to execute the above-mentioned method embodiments. Please refer to the above-mentioned embodiments for specific processes and detailed contents, which will not be repeated here.

[0087] Example 3

[0088] This embodiment provides a processing device corresponding to the asymmetric triggering step-down method of the thyristor converter provided in this embodiment 1. The processing device can be applicable to a client processing device, such as a mobile phone, a laptop computer, a tablet computer, a desktop computer, etc., to execute the method of embodiment 1.

[0089] The processing device includes a processor, a memory, a communication interface and a bus, and the processor, the memory and the communication interface are connected through the bus to complete mutual communication. The memory stores a computer program that can be run on the processing device, and the processing device executes the asymmetric triggering step-down method for the thyristor converter provided in this embodiment 1 when running the computer program.

[0090] In some implementations, the memory may be a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory.

[0091] In some other implementations, the processor may be a central processing unit (CPU), a digital signal processor (DSP), or other general-purpose processors of various types, which are not limited herein.

[0092] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0093] Those skilled in the art will understand that the structure of the above-mentioned computing device is only a partial structure related to the scheme of the present application, and does not constitute a limitation on the computing device to which the scheme of the present application is applied. The specific computing device may include more or fewer components, or combine certain components, or have a different arrangement of components.

[0094] Example 4

[0095] This embodiment provides a computer program product corresponding to the asymmetric triggering and voltage reduction method for the thyristor converter provided in this embodiment 1. The computer program product may include a computer-readable storage medium on which computer-readable program instructions for executing the asymmetric triggering and voltage reduction method for the thyristor converter described in this embodiment 1 are loaded.

[0096] Computer readable storage media can be tangible devices that hold and store instructions used by instruction execution devices. Computer readable storage media can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any combination thereof.

[0097] The above embodiment provides a computer-readable storage medium, whose implementation principle and technical effect are similar to those of the above method embodiment, and will not be repeated here.

[0098] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes 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.

[0099] 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 1 A function specified in one or more boxes.

[0100] 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.

[0101] The above embodiments are only used to illustrate the present invention, wherein the structure, connection mode and manufacturing process of each component may be changed. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A method for asymmetric triggering and voltage reduction of a thyristor converter, characterized in that: include: During the voltage reduction process on the rectifier side, the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter are controlled to be unequal, so as to suppress the reactive power generated by the three-phase thyristor converter during voltage reduction; The three thyristors of the first half bridge are triggered at intervals of 120°, and the three thyristors of the second half bridge are triggered at intervals of 120°; The method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal includes: Increase the trigger angle of the first half bridge and the second half bridge; When the trigger angle of the first half bridge is equal to the first preset value, the trigger angle of the first half bridge is controlled to remain unchanged, and the trigger angle of the second half bridge continues to increase; The method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes: Increase the trigger angle of the first half bridge and the second half bridge; When the trigger angle of the first half bridge is equal to the second preset value, the trigger angle of the first half bridge is controlled to decrease, and the trigger angle of the second half bridge is continuously increased; The method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes: Increase the trigger angle of the first half bridge and the second half bridge; When the trigger angle of the first half bridge is equal to the third preset value, the trigger angle of the first half bridge is controlled to jump to the fourth preset value, and the trigger angle of the second half bridge is continuously increased; Wherein, the fourth preset value is less than the third preset value; The method of controlling the thyristor trigger angle of the first half bridge and the thyristor trigger angle of the second half bridge of the three-phase thyristor converter to be unequal also includes: Controlling the trigger angle of the first half bridge to be fixed at a fifth preset value; Controlling the trigger angle of the second half bridge to be fixed at a sixth preset value; The fifth preset value and the sixth preset value are not equal.

2. An asymmetric triggering and voltage reduction system for a thyristor converter based on the asymmetric triggering and voltage reduction method for a thyristor converter according to claim 1, characterized in that: include: The processing unit is used to control the thyristor triggering angle of the first half bridge and the thyristor triggering angle of the second half bridge of the three-phase thyristor converter to be unequal during the voltage reduction process on the rectifier side, so as to suppress the reactive power generated by the three-phase thyristor converter during voltage reduction.

3. A processing device, characterized in that: The method comprises computer program instructions, wherein the computer program instructions are used to implement the steps corresponding to the asymmetric triggering voltage reduction method of the thyristor converter according to claim 1 when the computer program instructions are executed by a processing device.

4. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions, wherein the computer program instructions are used to implement the steps corresponding to the asymmetric triggering step-down method for the thyristor converter according to claim 1 when executed by the processor.

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