Hybrid power grid commutation converter control method and device, readable storage medium and computer equipment
By controlling the modulation voltage of the full-bridge submodule in a hybrid LCC, it is ensured that the voltage of the phase-commuted bridge arm is smaller than the target bridge arm, and phase-commutation is completed in advance, solving the problem of reactive power compensation, improving the stability of the system and grid connection Enter friendly.
Patent Information
- Application Number
- CN202411160901.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-22
- Publication Date
- 2025-01-03
AI Technical Summary
The prior art is difficult to accurately and timely realize reactive power compensation, which causes hybrid LCCs to consume a large amount of reactive power during phase commutation and rely too much on external power input, affecting the complexity of their access to the power grid and the operation stability of the AC and DC system. .
During the phase commutation process, by controlling the modulation voltage of the full-bridge submodule, ensure that the voltage of the phase commutation bridge arm is smaller than the target bridge arm before the natural phase commutation point, start phase commutation in advance, and complete phase commutation at the natural phase commutation point , thereby reducing reactive power interaction and improving operational stability.
The phase commutation is achieved before the natural phase commutation point, reducing reactive power interaction, and improving the grid access friendliness of hybrid LCCs and the operation stability of the entire AC and DC system.
Smart Images
Figure CN119254036A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of phase-commutation converter control, and in particular relates to a hybrid power grid phase-commutation converter control method, device, readable storage medium and computer equipment. Background Art
[0002] In order to keep up with the trend of energy technology progress and promote the clean and low-carbon transformation of energy, the power industry must build a new power system with new energy as the main body and promote the high-quality development of clean energy. However, my country's clean energy and load centers generally show an inverse distribution pattern, and the electricity produced by clean energy needs to be transferred on a large scale and across regions. At present, the thyristor-based grid-commutated converter (LCC) type high-voltage direct current transmission technology has the advantages of long transmission distance, large transmission capacity, low power loss and low engineering cost. It is one of the mainstream solutions for large-scale new energy transmission.
[0003] Since LCC uses semi-controlled power electronic devices as the commutation elements of the converter, it does not have the ability of self-commutation and requires an AC system of a certain strength to provide it with commutation voltage. At the same time, it consumes a lot of reactive power during operation, and a large number of passive filters and parallel capacitors must be configured for reactive power compensation. However, my country's new energy resource-rich areas are often located in remote areas with weak grid architecture. They are typical weak grids with characteristics such as weak thermal power support, insufficient short-circuit capacity, and limited voltage regulation capabilities. When LCC is connected to a weak grid, if the AC system voltage fluctuates to a certain extent, it is easy to cause fluctuations in the system's active power and reactive power. Since the parallel capacitor has a slow adjustment speed, the dynamic reactive power compensation capability of the AC system voltage is also slow, and the voltage stability of the sending-end AC system is poor, which limits the application of LCC in weak grid scenarios.
[0004] In response to the above problems, some experts and scholars have proposed a hybrid grid-commutated converter (hybrid LCC), whose topology is as follows: Figure 1 As shown in the figure, the difference from the conventional LCC is that the hybrid LCC connects a certain number of full-bridge sub-modules composed of fully-controlled devices IGBT in series between the converter transformer and the LCC, which is equivalent to connecting a controllable voltage source between the two. When the AC system voltage fluctuates, the AC system voltage fluctuation can be suppressed or the thyristor valve commutation voltage can be compensated by controlling the full-bridge sub-module valve output voltage, thereby improving the operating stability of the LCC, allowing the LCC to be connected to a weaker AC power grid, and expanding its application scenarios.
[0005] However, for the topology of the hybrid LCC, the existing reactive power control method is usually still to compensate for the reactive power of the external input to the AC side of the hybrid LCC. This method is difficult to achieve reactive power compensation accurately and timely, resulting in the need to consume a large amount of reactive power during the commutation process of the hybrid LCC. In addition, the excessive reliance on external power input makes it more complicated for the hybrid LCC to access the power grid, and even affects the operating status of the AC / DC system. Summary of the invention
[0006] The object of the present invention is to provide a hybrid grid commutation converter control method, device, readable storage medium and computer equipment to solve the problem that it is difficult to accurately and timely realize reactive power compensation in the prior art, resulting in that a large amount of reactive power may still be consumed during the commutation process of the hybrid LCC and excessive reliance on external power input.
[0007] In order to achieve the above-mentioned object, the present invention provides a hybrid power grid commutation converter control method, which, when the commutated bridge arm of the thyristor valve in the commutation converter commutates to the target bridge arm, starts from the opening moment of the target bridge arm for a set time before the moment corresponding to the natural commutation point, and controls the modulation voltage values of the full-bridge submodule valves in the commutation converter corresponding to the target bridge arm and the commutated bridge arm to be the modulation voltage command value within the set time, and the modulation voltage values are respectively the same as the AC bus voltage and the opposite direction;
[0008] The set duration is the duration corresponding to the thyristor valve trigger angle obtained according to the active type control of the phase-commutating converter;
[0009] The modulation voltage command value includes a modulation voltage theoretical value; the theoretical value is obtained according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative product of the product and the cosine of the thyristor valve trigger angle, the DC current sampling value and the product of the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance, and the absolute value of the thyristor valve trigger angle.
[0010] As a new hybrid power grid commutation converter control method, the present invention has the following beneficial effects: after analysis, the commutation condition can be met only when the voltage of the commutated bridge arm is less than the target bridge arm, and under normal circumstances, the voltage of the commutated bridge arm will be less than the target bridge arm only after the moment corresponding to the natural commutation point; on the basis of this analysis, the present invention controls the full-bridge sub-module valves accordingly by modulating the voltage of the full-bridge sub-module valves of the target bridge arm corresponding to the same direction as the AC bus voltage, modulating the voltage of the full-bridge sub-module valves of the commutated bridge arm corresponding to the opposite direction to the AC bus voltage, and setting the modulation voltage command value, so that at the moment of the duration corresponding to the trigger angle of the thyristor valve before the natural commutation point, the voltage of the target bridge arm can be actively increased while the voltage of the commutated bridge arm can be reduced, so as to maximize the It is obtained that the voltage of the switched bridge arm at this moment (before the natural switching point) can be less than the target bridge arm, thereby providing the condition to ensure that the switched bridge arm is switched to the target bridge arm, and ensuring that the thyristor valve (LCC) can start switching in advance at the time corresponding to the thyristor valve trigger angle before the natural switching point; at the same time, combined with the modulation voltage theoretical value of the full-bridge sub-module valve that can enable the thyristor bridge arm of the thyristor valve to complete the switching at the natural switching point, it is possible to achieve the effect of completing the switching at the moment corresponding to the natural switching point as much as possible, thereby controlling the switching converter not to generate reactive power interaction with the AC system during switching, so as to avoid the hybrid LCC consuming a large amount of reactive power during the switching process, and also make the hybrid grid-switch converter friendly to grid access, which is helpful to improve the operating stability of the entire AC / DC system.
[0011] Furthermore, the modulation voltage command value also includes a reactive compensation amount superimposed on the modulation voltage theoretical value; the reactive compensation amount is determined according to a control amount obtained by performing proportional integral control on the difference between the set reactive command value and the actual value of reactive power on the AC side of the converter;
[0012] When the reactive power flows from the AC system to the commutation converter in the positive direction, if the commutation converter needs to be controlled to output reactive power, the reactive command value is set to be less than 0; if the commutation converter needs to be controlled to absorb reactive power, the reactive command value is set to be greater than 0; if there is no reactive power interaction between the commutation converter and the AC system, the reactive command value is set to be equal to 0;
[0013] When the reactive power flows from the phase-commutating converter to the AC system in the positive direction, if the phase-commutating converter needs to be controlled to output reactive power, the reactive command value is set to be greater than 0; if the phase-commutating converter needs to be controlled to absorb reactive power, the reactive command value is set to be less than 0; if there needs to be no reactive power interaction between the phase-commutating converter and the AC system, the reactive command value is set to be equal to 0.
[0014] Further, the method of obtaining the theoretical value of the modulation voltage according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative product of the product and the cosine of the thyristor valve trigger angle, the ratio of the product of the DC current sampling value and the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance to the absolute value of the thyristor valve trigger angle includes:
[0015]
[0016] Among them, U ctrl1 is the theoretical value of the full-bridge submodule valve modulation voltage; k is the primary-to-secondary ratio of the converter transformer, U ac is the effective value of the AC bus voltage, cosα is the cosine of the thyristor valve trigger angle, ω is the angular velocity corresponding to the AC bus voltage frequency, L is the equivalent commutation inductance, I dc is the DC current sampling value.
[0017] Furthermore, the target bridge arm starts from the opening time of the set time before the time corresponding to the natural commutation point. Within the set time, the modulation voltage of the full-bridge sub-module valve in the commutation converter corresponding to the target bridge arm and the commutated bridge arm is controlled to be a positive value and a negative value of the modulation voltage command value respectively. The method includes:
[0018] When a rising edge of an opening trigger pulse sent to a target bridge arm is detected, a flag corresponding to the bridge arm is set to a first flag value, and after waiting for a set time, the flag corresponding to the bridge arm is set to another flag value; the opening trigger pulse is sent to the target bridge arm at the opening time;
[0019] When the mark corresponding to the first bridge arm or the sixth bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter of the A phase is controlled to be the positive value of the modulation voltage command value; when the mark corresponding to the third bridge arm or the fourth bridge arm is the first mark value, the modulation voltage of the A phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the A phase is controlled to be 0;
[0020] When the mark corresponding to the second bridge arm or the third bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter controlling the B phase is the positive value of the modulation voltage command value; when the mark corresponding to the fifth bridge arm or the sixth bridge arm is the first mark value, the modulation voltage of the B phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the B phase is controlled to be 0;
[0021] When the mark corresponding to the fourth bridge arm or the fifth bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter controlling the C phase is the positive value of the modulation voltage command value; when the mark corresponding to the first bridge arm or the second bridge arm is the first mark value, the modulation voltage of the C phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the C phase is controlled to be 0;
[0022] The first bridge arm is the upper bridge arm corresponding to thyristor valve A; the second bridge arm is the lower bridge arm corresponding to thyristor valve C; the third bridge arm is the upper bridge arm corresponding to thyristor valve B; the fourth bridge arm is the lower bridge arm corresponding to thyristor valve A; the fifth bridge arm is the upper bridge arm corresponding to thyristor valve C; the sixth bridge arm is the lower bridge arm corresponding to thyristor valve B;
[0023] The positive direction of the modulation voltage of the full-bridge submodule valve is consistent with the positive direction of the AC bus voltage.
[0024] Furthermore, the method of obtaining the thyristor valve trigger angle according to the active type control of the phase-commutating converter includes:
[0025] The control amount is obtained by performing proportional-integral control on the difference between the DC current command value and the actual value of the DC current on the DC side of the converter, and the thyristor valve trigger angle is obtained.
[0026] Furthermore, the DC current command value is determined based on the DC current control target value of the converter, the negative product of the quotient of the droop coefficient and the DC voltage sampling value and the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value, the negative product of the quotient of the AC bus voltage frequency rated value and the DC voltage sampling value and the moment of inertia, and the differential of the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value.
[0027] Further, the DC current command value is determined according to the inverter DC current control target value, the negative product of the quotient of the droop coefficient and the DC voltage sampling value and the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value, the negative product of the quotient of the AC bus voltage frequency rated value and the DC voltage sampling value and the moment of inertia, and the differential of the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value, including:
[0028]
[0029] Among them, I dc_ref is the DC current command value, k f is the droop coefficient, U dc is the DC voltage sampling value, f N is the rated value of the AC bus voltage frequency, f is the sampling value of the AC bus voltage frequency, and J is the moment of inertia; I dcn is the target value for converter DC current control.
[0030] The present invention also provides a computer device, comprising a processor, wherein the processor is used to execute a computer program to implement the steps of the hybrid power grid phase-commutated converter control method.
[0031] The computer device can achieve the same beneficial effects as the above-mentioned hybrid power grid phase-commutated converter control method.
[0032] The present invention also provides a readable storage medium, in which computer executable instructions are stored. The computer executable instructions are used to implement the above-mentioned hybrid power grid phase-commutated converter control method when being executed.
[0033] The readable storage medium can achieve the same beneficial effects as the above-mentioned hybrid grid phase-commutated converter control method.
[0034] The present invention also provides a hybrid power grid phase-commutation converter control device, which includes a thyristor valve phase-commutation module and a modulation voltage instruction generation module; the modulation voltage instruction generation module includes a modulation voltage theoretical value calculation submodule;
[0035] The thyristor valve commutation module is used to realize that when the commutated bridge arm of the thyristor valve in the commutation converter commutates to the target bridge arm, starting from the opening moment of the target bridge arm at a set time before the moment corresponding to the natural commutation point, the modulation voltage values of the full-bridge sub-module valves in the commutation converter corresponding to the target bridge arm and the commutated bridge arm are all modulation voltage command values within the set time, and are respectively in the same direction and opposite direction to the AC bus voltage;
[0036] The modulation voltage instruction generation module is used to generate a modulation voltage instruction value including the modulation voltage theoretical value calculated by the modulation voltage theoretical value calculation submodule;
[0037] The modulation voltage theoretical value calculation submodule is used to obtain the modulation voltage theoretical value according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative of the product of the product and the cosine of the thyristor valve trigger angle, the DC current sampling value and the product of the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance and the absolute value of the thyristor valve trigger angle.
[0038] The technical solution of the hybrid grid phase-commutated converter control device of the present invention can achieve the same beneficial effects as the hybrid grid phase-commutated converter control method described above. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Figure 1 A topological diagram of a hybrid power grid phase-commutation converter in the background technology of the present invention;
[0040] Figure 2 is an equivalent circuit diagram of a hybrid power grid commutation converter in an embodiment of a hybrid power grid commutation converter control method of the present invention;
[0041] Figure 3The waveform diagram of voltage and current during the phase commutation from arm 1 to arm 3 of a conventional grid-commutated converter in the embodiment of the hybrid grid-commutated converter control method of the present invention;
[0042] Figure 4 The voltage and current waveform diagrams during the phase commutation process from the bridge arm 1 to the bridge arm 3 of the hybrid power grid phase commutation converter in the embodiment of the hybrid power grid phase commutation converter control method of the present invention;
[0043] Figure 5 A block diagram of a hybrid power grid phase-commutated converter control method in an embodiment of the hybrid power grid phase-commutated converter control method of the present invention;
[0044] Figure 6 It is a block diagram of a reactive control link of a hybrid power grid commutation converter including a reactive compensation amount superimposed on a modulated voltage theoretical value in an embodiment of a hybrid power grid commutation converter control method of the present invention;
[0045] Figure 7 It is a waveform diagram of independent control of AC side power of a hybrid power grid commutation converter in an embodiment of a hybrid power grid commutation converter control method of the present invention;
[0046] Figure 8 It is a DC voltage waveform diagram of the hybrid grid commutation converter in the embodiment of the hybrid grid commutation converter control method of the present invention when the hybrid grid commutation converter is in state 2;
[0047] Fig. 9 It is a dynamic support waveform diagram of the frequency of the AC system of the hybrid power grid commutation converter in the embodiment of the hybrid power grid commutation converter control method of the present invention. DETAILED DESCRIPTION
[0048] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.
[0049] Hybrid power grid phase-commutation converter control method embodiment
[0050] This embodiment provides a hybrid grid commutation converter control method. When the commutated bridge arm of the thyristor valve in the commutation converter commutates to the target bridge arm, the method starts from the opening moment of the target bridge arm for a set time before the moment corresponding to the natural commutation point, and controls the modulation voltage values of the full-bridge sub-module valves in the commutation converter corresponding to the target bridge arm and the commutated bridge arm to be the modulation voltage command value within the set time, and the modulation voltage values are respectively the same as the AC bus voltage and the opposite direction;
[0051] The above-mentioned set duration is the duration corresponding to the thyristor valve trigger angle obtained according to the active type control of the phase-commutating converter;
[0052] The modulation voltage command value includes a modulation voltage theoretical value; the above theoretical value is obtained according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative product of the product and the cosine of the thyristor valve trigger angle, the DC current sampling value and the product of the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance and the absolute value of the thyristor valve trigger angle.
[0053] Specifically, based on Figure 1 The equivalent circuit diagram of the hybrid grid-commutated converter with the topology shown is as follows Figure 2 As shown in FIG. 1 (i.e., each corresponding full-bridge sub-module valve of the thyristor valve in the commutation converter is equivalent to the corresponding controllable voltage source), the commutation process of the conventional grid commutation converter is taken as a reference, and the thyristor V T1 To V T3 Taking phase switching as an example, the voltage waveform of the phase-switch bridge arm corresponding to the phase (i.e., phase A) and the voltage and current waveforms of the target bridge arm corresponding to the phase (i.e., phase B) of the AC system during the phase switching process are as follows: Figure 3 As shown in the figure, u a and u b are the AC voltage waveforms corresponding to phase A and phase B, i b is the AC current waveform of phase B, m is the natural commutation point (the natural commutation point mentioned in this embodiment refers to the natural commutation point where the commutated bridge arm commutates to the target bridge arm, for example, here it refers to the natural commutation point between phase A and phase B), α is the trigger angle, and the value of α can be obtained according to the active control link of the existing commutation converter; UU and II are the center lines of the positive half-wave of the AC voltage and the AC current respectively. Figure 3 It can be analyzed that in order to satisfy V T3 The anode voltage is greater than the cathode voltage, and the commutation process must occur at u b >u a In the stage, ignoring the influence of the commutation overlap angle, the angle of UU leading II is α, so the conventional LCC converter will inevitably consume reactive power during normal operation.
[0054] Therefore, combined with the above analysis, it can be concluded that during the commutation process, if the current commutation completion time is moved to the natural commutation point, that is, the neutral line UU and the neutral line II are coincident, the commutation can be completed as much as possible at the time corresponding to the natural commutation point, so that the converter does not generate reactive power interaction with the AC system. T1 To V T3 For example, in the commutation process of the hybrid power grid commutation converter, the trigger angle can be set to a negative value of α (with the natural commutation point as the reference time), and the A-phase and B-phase full-bridge sub-module valves output the same amplitude and opposite direction of the modulation voltage U ctrlA , UctrlB The end time of the commutation process is regulated, that is, the hybrid power grid commutation converter completes the commutation at the natural commutation point. During this process, the AC side voltage of the thyristor valve satisfies: u b +U ctrlB >u a +U ctrlA .
[0055] In summary, the switching condition can only be met when the voltage of the switched bridge arm is less than the target bridge arm, and under normal circumstances, the voltage of the switched bridge arm will be less than the target bridge arm only after the moment corresponding to the natural switching point; therefore, the hybrid power grid switching converter control method of this embodiment controls the full-bridge sub-module valve accordingly by modulating the voltage of the full-bridge sub-module valve of the target bridge arm corresponding to the same direction as the AC bus voltage, modulating the voltage of the full-bridge sub-module valve of the switched bridge arm corresponding to the phase opposite to the AC bus voltage, and setting the modulation voltage command value, so that the thyristor valve trigger angle can be actively increased at the moment before the natural switching point. The voltage of the target bridge arm simultaneously reduces the voltage of the switched bridge arm, and tries to make the voltage of the switched bridge arm at this moment (before the natural switching point) be smaller than the target bridge arm, thereby providing the conditions to ensure that the switched bridge arm is switched to the target bridge arm, and ensuring that the thyristor valve (LCC) can start switching in advance at the time corresponding to the thyristor valve trigger angle before the natural switching point. At the same time, combined with the modulation voltage theoretical value of the full-bridge sub-module valve that enables the thyristor bridge arm of the thyristor valve to complete the switching at the natural switching point, the effect of completing the switching at the moment corresponding to the natural switching point can be achieved, and the switching converter can be controlled not to generate reactive power interaction with the AC system during switching.
[0056] Specifically, refer to Figure 5 In this embodiment, the method of obtaining the theoretical value of the modulation voltage according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative product of the product and the cosine of the thyristor valve trigger angle, the product of the DC current sampling value and the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance and the absolute value of the thyristor valve trigger angle respectively includes:
[0057]
[0058] Among them, U ctrl1 is the theoretical value of the modulation voltage; k is the primary-to-secondary ratio of the converter transformer of the hybrid commutation converter, U ac is the effective value of the AC bus voltage, cosα is the cosine of the thyristor valve trigger angle of the hybrid commutation converter, ω is the angular velocity corresponding to the AC bus voltage frequency, L is the equivalent commutation inductance, I dc is the DC current sampling value.
[0059] In the hybrid grid commutation converter control method of this embodiment, the modulation voltage output by the full-bridge sub-module valve during the commutation process needs to ensure that the thyristor bridge arm of the thyristor valve completes the commutation at the natural commutation point. T1 To V T3 For example, during the commutation process, V T1 and V T3 At the same time, according to Figure 2 The commutation process shown and Kirchhoff's voltage law can be obtained:
[0060]
[0061] I dc It is a constant during normal operation, and its value after derivation is 0. At the same time, it is assumed that U ctrlB =-U ctrlA =U ctrl1 , the above formula can be simplified as: Provisions a and u b The natural commutation point is zero, so we can assume according to Figure 4 It can be seen that V T3 The moment of applying the trigger pulse signal At this time, the AC current of phase b should be zero, and the differential equations are as follows:
[0062]
[0063] The mathematical expression of the AC current of phase b can be calculated by the simultaneous equations:
[0064]
[0065] In order to achieve no reactive power interaction between the series hybrid commutation converter and the AC system, that is, to make V T1 and V T3 The commutation is completed at the natural commutation point, so i b (0) = I dc , substituting into the above formula, we can calculate:
[0066]
[0067] Based on the above theoretical derivation, in the calculation link of the modulation voltage theoretical value of this embodiment, the input quantities are the converter thyristor valve trigger angle α, the DC current sampling value I dc , AC bus voltage line voltage effective value U ac The output is the theoretical value of the modulation voltage U of the full-bridge submodule valve. ctrl1 , U ctrl1 The calculation formula is Where k is the primary-to-secondary transformation ratio of the converter transformer, ω is the angular velocity corresponding to the AC bus voltage frequency, and L is the equivalent commutation inductance.
[0068] In addition, refer to Figure 5 In this embodiment, the method of obtaining the thyristor valve trigger angle according to the active type control of the phase-commutated converter includes: dc_ref The actual value of the DC current on the DC side of the converter I dc The difference between the two is subjected to proportional integral control (PI control) to obtain the control amount, and the thyristor valve trigger angle (i.e., trigger angle α) is obtained. In other embodiments, other existing active type control methods for obtaining the thyristor valve trigger angle may also be used, which will not be repeated here.
[0069] And, refer to Figure 6 In this embodiment, the modulation voltage command value also includes a reactive compensation amount superimposed on the modulation voltage theoretical value; the reactive compensation amount is determined by a control amount obtained by performing proportional integral control on the difference between the set reactive command value and the actual value of reactive power on the AC side of the converter;
[0070] When the reactive power flows from the AC system to the commutation converter in the positive direction, if the commutation converter needs to be controlled to output reactive power, the reactive command value is set to be less than 0; if the commutation converter needs to be controlled to absorb reactive power, the reactive command value is set to be greater than 0; if there is no reactive power interaction between the commutation converter and the AC system, the reactive command value is set to be equal to 0;
[0071] When the reactive power flows from the phase-commutating converter to the AC system in the positive direction, if the phase-commutating converter needs to be controlled to output reactive power, the reactive command value is set to be greater than 0; if the phase-commutating converter needs to be controlled to absorb reactive power, the reactive command value is set to be less than 0; if there needs to be no reactive power interaction between the phase-commutating converter and the AC system, the reactive command value is set to be equal to 0.
[0072] In fact, the full-bridge submodule valve is based on the modulation voltage theoretical value U ctrl1 When outputting voltage, theoretically, the thyristor bridge arm can complete the commutation at the natural commutation point by controlling the modulation voltage command value. However, due to the commutation process, the AC current will slightly lead the AC voltage. The hybrid grid commutation converter still outputs reactive power to the AC system, which does not mean that there is no reactive power interaction with the AC system. If you want to control the interactive reactive power more accurately and flexibly, you can adjust the modulation voltage theoretical value U ctrl1Additional compensation is performed to obtain the final modulation voltage command value used for regulation. If the compensation amount is a positive value, the entire commutation process ends ahead of schedule. At this time, the AC current has a larger lead than the AC voltage, and the hybrid power grid commutation converter outputs more reactive power. If the compensation amount is a negative value, the entire commutation process ends with a delay. At this time, the AC current can even become a lagging AC voltage, and the hybrid power grid commutation converter absorbs reactive power. Therefore, in this embodiment, the modulation voltage command value also includes a reactive compensation amount superimposed on the theoretical value of the modulation voltage. The reactive compensation amount is equivalent to closed-loop control of reactive power in the control link corresponding to the modulation voltage command value of the hybrid power grid commutation converter. Specifically, the input quantity of the closed-loop control is the reactive power command value Q on the AC side of the converter. ref (i.e., the set reactive power command value) and the sampling value Q (i.e., the actual reactive power value on the AC side of the converter), the output is the full-bridge submodule valve modulation voltage compensation value U ctrl2 ; In this closed-loop control, Q ref The difference between Q and Q is used as the input of the proportional-integral controller of the closed-loop control. The output of the proportional-integral controller is assigned to U ctrl2 , such as Figure 6 As shown, U ctrl2 The negative value of is the reactive compensation amount contained in the modulation voltage command value and superimposed on the modulation voltage theoretical value. ctrl1 and U ctrl2 Get U ctrl It can be seen that in this embodiment, it is stipulated that the reactive power flowing from the AC system to the phase-commutated converter is positive. According to the control logic of the reactive power closed-loop control, if it is necessary to control the phase-commutated converter to output reactive power, the reactive power command value Q is set. ref Less than 0 (the reactive power command value can be set to the corresponding value according to the reactive power output); if the commutation converter needs to be controlled to absorb reactive power, the reactive power command value Q is set ref Greater than 0 (the reactive power command value can be set to the corresponding value according to the reactive power required to be absorbed); if it is necessary to control the reactive power interaction between the phase-commutated converter and the AC system, the reactive power command value Q is set ref In other embodiments, it can also be stipulated that reactive power flowing from the phase-commutated converter to the AC system is positive, and in this case, the reactive power command value Q is set ref Greater than 0; if you need to control the commutation converter to absorb reactive power, set the reactive power command value Q ref Less than 0; if it is necessary to control the reactive power interaction between the commutation converter and the AC system, the reactive power command value Q is set ref Just equal to 0.
[0073] In other embodiments, other existing compensation amounts may be adaptively added to the modulation voltage command value according to other requirements, which will not be described in detail here.
[0074] The modulation voltage of the full-bridge sub-module valve in the commutation converter corresponding to the phase of the target bridge arm and the commutated bridge arm is respectively a positive value and a negative value of the modulation voltage instruction value, which is embodied in this embodiment as follows: when the rising edge of the opening trigger pulse sent to the target bridge arm is detected (equivalent to when the trigger pulse signal P1 corresponding to the thyristor valve bridge arm 1 is issued), the value of the flag P1_flag corresponding to the bridge arm to be controlled by P1 is set to 1, and after waiting for a set time, the value of P1_flag is set to 0; when P1 is issued next time, the value of P1_flag is repeatedly set to 1, and the flags P2_flag, P3_flag, ..., P6_flag corresponding to the trigger pulse signals P2, P3, ..., P6 of other thyristor valve bridge arms have the same setting logic as the flag P1_flag corresponding to the trigger pulse signal P1 of the above-mentioned thyristor valve bridge arm 1.
[0075] Specifically, in order to enable the thyristor valve bridge arm in the hybrid converter to complete the commutation at the natural commutation point without affecting the normal operation of the thyristor valve after the commutation process is completed, the duration of the full-bridge submodule valve output voltage (i.e., the above-mentioned set duration) should be the duration corresponding to the electrical angle of the trigger angle, that is, At the same time, if Figure 4 As shown, the logic of the commutation process is based on the thyristor V T1 To V T3 Taking commutation as an example, in order to make the voltage of the B-phase port of the thyristor valve AC side greater than the voltage of the A-phase port during commutation, the A-phase full-bridge sub-module valve needs to output a negative voltage, the B-phase full-bridge sub-module valve needs to output a positive voltage with the same amplitude as the negative voltage output by the A-phase full-bridge sub-module valve, and the C-phase full-bridge sub-module valve needs to output zero voltage. T2 To V T4 During phase switching, the A-phase full-bridge sub-module valve needs to output a negative voltage, the B-phase full-bridge sub-module valve needs to output a zero voltage, and the C-phase full-bridge sub-module valve needs to output a positive voltage equal to the negative voltage output by the A-phase full-bridge sub-module valve; the thyristor V T3 To V T5 During phase switching, the A-phase full-bridge submodule valve needs to output zero voltage, the B-phase full-bridge submodule valve needs to output a negative voltage, and the C-phase full-bridge submodule valve needs to output a positive voltage equal to the negative voltage output by the B-phase full-bridge submodule valve; the thyristor V T4 To V T6 During phase switching, the A-phase full-bridge sub-module valve needs to output a positive voltage, the B-phase full-bridge sub-module valve needs to output a negative voltage with the same amplitude as the positive voltage output by the A-phase full-bridge sub-module valve, and the C-phase full-bridge sub-module valve needs to output zero voltage; the thyristor V T5To V T1 During phase switching, the A-phase full-bridge sub-module valve needs to output a positive voltage, the B-phase full-bridge sub-module valve needs to output a zero voltage, and the C-phase full-bridge sub-module valve needs to output a negative voltage equal to the positive voltage output by the A-phase full-bridge sub-module valve; the thyristor V T6 To V T2 During commutation, the A-phase full-bridge sub-module valve needs to output zero voltage, the B-phase full-bridge sub-module valve needs to output positive voltage, and the C-phase full-bridge sub-module valve needs to output a negative voltage with the same amplitude as the positive voltage output by the B-phase full-bridge sub-module valve. In addition, referring to the modulation voltage command value of the full-bridge sub-module valve that includes the modulation voltage theoretical value that enables the thyristor bridge arm of the thyristor valve to complete commutation at the natural commutation point, in the above commutation process, whether the full-bridge sub-module valve outputs a positive value or a negative value, its absolute value needs to be the modulation voltage command value U ctrl .
[0076] In order to facilitate the control logic of the above-mentioned commutation process, in this embodiment, starting from the opening moment of the target bridge arm for a set time before the moment corresponding to the natural commutation point, within the set time, the modulation voltage of the full-bridge sub-module valve in the commutation converter corresponding to the phase of the target bridge arm and the commutated bridge arm is controlled to be respectively the positive value and the negative value of the modulation voltage command value, including:
[0077] When a rising edge of an opening trigger pulse sent to a target bridge arm is detected, a flag corresponding to the bridge arm is set to a first flag value, and after waiting for a set time, the flag corresponding to the bridge arm is set to another flag value; the opening trigger pulse is sent to the target bridge arm at the above opening time;
[0078] When the mark corresponding to the first bridge arm or the sixth bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter of the A phase is controlled to be the positive value of the modulation voltage command value; when the mark corresponding to the third bridge arm or the fourth bridge arm is the first mark value, the modulation voltage of the A phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the A phase is controlled to be 0;
[0079] When the mark corresponding to the second bridge arm or the third bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter controlling the B phase is the positive value of the modulation voltage command value; when the mark corresponding to the fifth bridge arm or the sixth bridge arm is the first mark value, the modulation voltage of the B phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the B phase is controlled to be 0;
[0080] When the mark corresponding to the fourth bridge arm or the fifth bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter controlling the C phase is the positive value of the modulation voltage command value; when the mark corresponding to the first bridge arm or the second bridge arm is the first mark value, the modulation voltage of the C phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the C phase is controlled to be 0; the above-mentioned first bridge arm is the upper bridge arm corresponding to A (i.e. Figure 1 The second bridge arm is the lower bridge arm corresponding to C (i.e. Figure 1 The third bridge arm is the upper bridge arm corresponding to B (i.e. Figure 1 The fourth bridge arm is the lower bridge arm corresponding to A (i.e. Figure 1 The fifth bridge arm is the upper bridge arm corresponding to C (i.e. Figure 1 The sixth bridge arm is the lower bridge arm corresponding to B (i.e. Figure 1 wherein the modulation voltage of the full-bridge sub-module valve (ie, the modulation voltage U output by the full-bridge sub-module valve) ctrlA , U ctrlA and U ctrlC ) is consistent with the positive direction of the AC bus voltage.
[0081] The control logic of this embodiment is as follows: Figure 5 , 6 The full-bridge submodule valve modulation voltage actual value logic selection link (i.e. Figure 5 , 6 The input of the logic selection link is the trigger angle α of the converter thyristor valve, the modulation voltage command value U ctrl And the trigger pulse signals P1~P6 of the thyristor valve bridge arm 1 to bridge arm 6, the output is the actual value U of the modulation voltage of the full bridge sub-module valve connected to phase A, phase B and phase C ctrlA , U ctrlA and U ctrlC , in the selection logic link, U ctrl The calculation formula is U ctrl =U ctrl1 -U ctrl2 , the specific selection logic is:
[0082] Detect the rising edge of the trigger pulse signal P1 of the thyristor valve bridge arm 1, and after detecting the rising edge, set the value of the flag P1_flag to 1 (i.e., the first flag value, which is set to 1 here for the convenience of computer recognition, and can be set to other values in other embodiments, or even letters or other characters, as long as it can be recognized during control), and wait After a certain time, the value of P1_flag is set to 0 (i.e., an arbitrary other flag value, which is set to 0 here for the convenience of computer recognition. In other embodiments, it can be set to other values, as long as it can be guaranteed to be recognized during control and is not the same as the first flag value to avoid misidentification). After the next rising edge of the trigger pulse signal P1 is detected, the above flag value setting is continued, and this cycle is repeated. At the same time, the flags P2_flag to P6_flag corresponding to the other thyristor bridge arms also refer to the processing logic of the bridge arm 1 in real time to set the flag value; based on the setting logic of the flag value, the following logical judgment is performed to determine U ctrlA , U ctrlA and U ctrlC Values:
[0083] When P1_flag = 1 or P6_flag = 1, let U ctrlA =U ctrl , when P3_flag=1 or P4_flag=1, let U ctrlA =-U ctrl , otherwise, let U ctrlA =0;
[0084] When P2_flag = 1 or P3_flag = 1, let U ctrlB =U ctrl , when P5_flag=1 or P6_flag=1, let U ctrlB =-U ctrl , otherwise, let U ctrlB =0;
[0085] When P4_flag = 1 or P5_flag = 1, let U ctrlC =U ctrl , when P1_flag=1 or P2_flag=1, let U ctrlC =-U ctrl , otherwise, let U ctrlC =0;
[0086] At the same time, in this embodiment, it is stipulated that the positive direction of the full-bridge submodule valve output voltage is consistent with the positive direction of the AC bus voltage. ctrlA , U ctrlA and U ctrlC The essence of the judgment logic of the value is to summarize, generalize and classify the logic of the above-mentioned commutation process according to the conditions, and is more suitable for running through conditional judgment statements. Therefore, it is easy to implement through computers. Even if it is implemented by manpower, the implementation method is simpler, the logic is clearer, and the control efficiency can be improved.
[0087] On the basis of the CIGRE standard model in the PSCAD / EMTDC software, the rectifier-side converter of the DC system is modified to be a hybrid grid-commutated converter and the control method of the hybrid grid-commutated converter proposed in this embodiment is verified. Figure 7 It is an independent power control waveform of the AC side of the hybrid power grid commutation converter. Before 4s, the hybrid converter controls the active power of the AC side to 500MW and the reactive power to 0MVar; at 4s, the active power of the AC side is controlled to 600MW and the reactive power is 0MVar; at 5s, the active power of the AC side is controlled to 500MW and the reactive power is 0MVar; at 6s, the active power of the AC side is controlled to 400MW and the reactive power is 0MVar; at 7s, the active power of the AC side is controlled to 500MW and the reactive power is 0MVar; at 8s, the active power of the AC side is controlled to 500MW and the reactive power is 50MVar; at 9s, the active power of the AC side is controlled to 500MW and the reactive power is 0MVar; at 10s, the active power of the AC side is controlled to 500MW and the reactive power is -50MVar; at 11s, the active power of the AC side is controlled to 500MW and the reactive power is 0MVar.
[0088] Specifically, for the active control of the hybrid grid commutation converter, the commutation process is not considered. Under normal circumstances, the thyristor valve of the hybrid grid commutation converter has six working states in one AC voltage cycle. In each state, two thyristor valves are turned on at the same time. For the convenience of subsequent analysis, refer to Figure 1 , define V T1 、V T2 When both are turned on, it is state 1, V T2 、V T3 When both are turned on, it is state 2, V T3 、V T4 When both are turned on, it is state 3, V T4 、V T5 When both are turned on, it is state 4, V T5 、V T6 When both are turned on, it is state 5, V T6 、V T1 When they are turned on at the same time, it is state 6. The DC side voltage of the thyristor valve in different working states is u ac 、u bc 、u ba 、u ca 、u cb and u ab The main function of the thyristor valve is to introduce the AC side voltage into the DC side by controlling the conduction of different thyristor valve bridge arms at a specific time.
[0089] like Figure 8As shown in the figure, the DC side voltage of the hybrid power grid commutation converter is analyzed by taking state 2 as an example. The entire state 2 can be divided into two stages from the time scale. Stage 1 (commutation): V T1 、V T2 、V T3 Simultaneous conduction, stage 2 (commutation completed): V T2 、V T3 During phase 1, the DC side voltage u dc Satisfy the formula: At this time, due to U ctrlA and U ctrlB The same magnitude and opposite direction, U ctrlC The amplitude is zero, and the above formula can be rewritten as: During phase 2, the DC side voltage u of the hybrid grid commutation converter is dc Satisfy the formula: u dc =u bc Therefore, the DC voltage waveform of the hybrid power grid commutation converter during state 2 is as follows: Figure 8 shown.
[0090] Assumptions but Where k is the primary-to-secondary ratio of the converter transformer, U ac is the effective value of the AC voltage line voltage, according to Figure 8 The DC voltage calculation formula of the hybrid grid commutation converter is as follows:
[0091]
[0092] It can be seen from the above formula that the DC voltage of the hybrid grid-commutated converter is related to the trigger angle α, has nothing to do with the full-bridge submodule valve output voltage, and is basically consistent with the control characteristics of the conventional grid-commutated converter. Therefore, in this embodiment, reference can be made to the constant current control strategy of the conventional grid-commutated converter, and the DC current can be closed-loop controlled through the active control of the hybrid grid-commutated converter, and the trigger angle α can be calculated accordingly.
[0093] In order to realize the frequency support of the hybrid grid commutation converter to the AC system, the virtual synchronous machine control strategy can be used for reference. Considering that the hybrid grid commutation converter can only realize the dynamic support of the AC system frequency by changing the size of the absorbed power (DC transmission power) compared with the real generator, based on this concept, the DC current command value in this embodiment is determined according to the DC current control target value of the converter, the quotient of the droop coefficient and the DC voltage sampling value and the negative product of the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value, the negative product of the quotient of the AC bus voltage frequency rated value and the DC voltage sampling value and the moment of inertia, and the differential of the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value; the method of determining the DC current command value according to the above parameter values includes:
[0094]
[0095] Among them, I dc_ref is the DC current command value, k f is the droop coefficient, U dc is the DC voltage sampling value, f N is the rated value of the AC bus voltage frequency, f is the sampling value of the AC bus voltage frequency, and J is the moment of inertia; the droop coefficient and the moment of inertia can be adaptively adjusted according to the actual situation; I dcn is the target value of the converter DC current control. Fig. 9 The waveform shown is the dynamic support waveform of the AC system frequency of the hybrid grid commutation converter. It can be seen that the use of the DC current command value determined according to the above parameter values can enable the converter to provide a certain inertia and power support as expected according to the change of the AC system frequency. Specifically, when the AC system frequency decreases, the active power transmitted by the DC system is reduced according to the control algorithm, and when the AC system frequency increases, the active power transmitted by the DC system is increased according to the control algorithm.
[0096] Computer device embodiment
[0097] This embodiment provides a computer device, including a processor, wherein the processor is used to execute a computer program to implement the steps of the above-mentioned hybrid grid phase-commutated converter control method.
[0098] Since the specific working mode and working principle of the computer device of this embodiment have been described in detail in the above-mentioned hybrid power grid phase-commutated converter control method embodiment, they will not be repeated here.
[0099] Readable storage medium embodiment
[0100] This embodiment provides a readable storage medium, in which computer executable instructions are stored. The computer executable instructions are used to implement the hybrid power grid phase-commutated converter control method as described above when executed.
[0101] Since the working mode and working principle of the readable storage medium in this embodiment have been described in detail in the above-mentioned hybrid power grid phase-commutated converter control method embodiment, they will not be repeated here.
[0102] Embodiment of hybrid power grid phase-commutation converter control device
[0103] This embodiment provides a hybrid power grid phase-commutation converter control device, which includes a thyristor valve phase-commutation module and a modulation voltage instruction generation module; the modulation voltage instruction generation module includes a modulation voltage theoretical value calculation submodule;
[0104] The thyristor valve commutation module is used to realize that when the commutated bridge arm of the thyristor valve in the commutation converter commutates to the target bridge arm, starting from the opening moment of the target bridge arm at a set time before the moment corresponding to the natural commutation point, the modulation voltage values of the full-bridge sub-module valves in the commutation converter corresponding to the target bridge arm and the commutated bridge arm are all modulation voltage command values within the set time, and are respectively in the same direction and opposite direction to the AC bus voltage;
[0105] The modulation voltage instruction generation module is used to generate a modulation voltage instruction value including the modulation voltage theoretical value calculated by the modulation voltage theoretical value calculation submodule;
[0106] The modulation voltage theoretical value calculation submodule is used to obtain the modulation voltage theoretical value according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative of the product of the product and the cosine of the thyristor valve trigger angle, the DC current sampling value and the product of the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance and the absolute value of the thyristor valve trigger angle.
[0107] Since the working mode and working principle of the hybrid grid phase-commutated converter control device in this embodiment have been described in detail in the above-mentioned hybrid grid phase-commutated converter control method embodiment, they will not be repeated here.
[0108] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, but do not constitute a limitation to the present invention.
Claims
1. A hybrid power grid phase-commutation converter control method, characterized in that: When the switched bridge arm of the thyristor valve in the commutation converter commutates to the target bridge arm, starting from the opening moment of the target bridge arm for a set time before the moment corresponding to the natural commutation point, the modulation voltage values of the full-bridge sub-module valves in the commutation converter corresponding to the target bridge arm and the switched bridge arm are all the modulation voltage command values within the set time, and are respectively in the same and opposite directions as the AC bus voltage; The set duration is the duration corresponding to the thyristor valve trigger angle obtained according to the active type control of the phase-commutating converter; The modulation voltage command value includes a modulation voltage theoretical value; the theoretical value is obtained according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative product of the product and the cosine of the thyristor valve trigger angle, the DC current sampling value and the product of the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance, and the absolute value of the thyristor valve trigger angle.
2. The hybrid power grid phase-commutated converter control method according to claim 1, characterized in that: The modulation voltage command value also includes a reactive compensation amount superimposed on the modulation voltage theoretical value; the reactive compensation amount is determined by a control amount obtained by performing proportional integral control on the difference between the set reactive command value and the actual value of reactive power on the AC side of the converter; When the reactive power flows from the AC system to the commutation converter in the positive direction, if the commutation converter needs to be controlled to output reactive power, the reactive command value is set to be less than 0; if the commutation converter needs to be controlled to absorb reactive power, the reactive command value is set to be greater than 0; if there is no reactive power interaction between the commutation converter and the AC system, the reactive command value is set to be equal to 0; When the reactive power flows from the phase-commutating converter to the AC system in the positive direction, if the phase-commutating converter needs to be controlled to output reactive power, the reactive command value is set to be greater than 0; if the phase-commutating converter needs to be controlled to absorb reactive power, the reactive command value is set to be less than 0; if there needs to be no reactive power interaction between the phase-commutating converter and the AC system, the reactive command value is set to be equal to 0.
3. The hybrid grid phase-commutated converter control method according to claim 1, characterized in that: Methods for obtaining the theoretical value of the modulation voltage according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative product of the product and the cosine of the thyristor valve trigger angle, the ratio of the product of the DC current sampling value and the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance to the absolute value of the thyristor valve trigger angle include: Among them, U ctrl1 is the theoretical value of the full-bridge submodule valve modulation voltage; k is the primary-to-secondary ratio of the converter transformer, U ac is the effective value of the AC bus voltage, cosα is the cosine of the thyristor valve trigger angle, ω is the angular velocity corresponding to the AC bus voltage frequency, L is the equivalent commutation inductance, I dc is the DC current sampling value.
4. The hybrid grid commutation converter control method according to any one of claims 1 to 3, characterized in that: Starting from the opening moment of the target bridge arm for a set time before the moment corresponding to the natural commutation point, within the set time, the modulation voltage of the full-bridge sub-module valve in the commutation converter corresponding to the phase of the target bridge arm and the commutated bridge arm is controlled to be a positive value and a negative value of the modulation voltage command value respectively, including: When a rising edge of an opening trigger pulse sent to a target bridge arm is detected, a flag corresponding to the bridge arm is set to a first flag value, and after waiting for a set time, the flag corresponding to the bridge arm is set to another flag value; the opening trigger pulse is sent to the target bridge arm at the opening time; When the mark corresponding to the first bridge arm or the sixth bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter of the A phase is controlled to be the positive value of the modulation voltage command value; when the mark corresponding to the third bridge arm or the fourth bridge arm is the first mark value, the modulation voltage of the A phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the A phase is controlled to be 0; When the mark corresponding to the second bridge arm or the third bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter controlling the B phase is the positive value of the modulation voltage command value; when the mark corresponding to the fifth bridge arm or the sixth bridge arm is the first mark value, the modulation voltage of the B phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the B phase is controlled to be 0; When the mark corresponding to the fourth bridge arm or the fifth bridge arm is the first mark value, the modulation voltage of the full-bridge submodule valve in the phase-commutating converter controlling the C phase is the positive value of the modulation voltage command value; when the mark corresponding to the first bridge arm or the second bridge arm is the first mark value, the modulation voltage of the C phase is controlled to be the negative value of the modulation voltage command value, otherwise, the modulation voltage of the C phase is controlled to be 0; The first bridge arm is the upper bridge arm corresponding to thyristor valve A; the second bridge arm is the lower bridge arm corresponding to thyristor valve C; the third bridge arm is the upper bridge arm corresponding to thyristor valve B; the fourth bridge arm is the lower bridge arm corresponding to thyristor valve A; the fifth bridge arm is the upper bridge arm corresponding to thyristor valve C; the sixth bridge arm is the lower bridge arm corresponding to thyristor valve B; The positive direction of the modulation voltage of the full-bridge submodule valve is consistent with the positive direction of the AC bus voltage.
5. The hybrid grid commutation converter control method according to any one of claims 1 to 3, characterized in that: Methods for obtaining the thyristor valve trigger angle according to the active type control of the phase-commutated converter include: The control amount is obtained by performing proportional-integral control on the difference between the DC current command value and the actual value of the DC current on the DC side of the converter, and the thyristor valve trigger angle is obtained.
6. The hybrid grid phase-commutated converter control method according to claim 5, characterized in that: The DC current command value is determined based on the DC current control target value of the converter, the negative product of the quotient of the droop coefficient and the DC voltage sampling value and the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value, the negative product of the quotient of the AC bus voltage frequency rated value and the DC voltage sampling value and the moment of inertia, and the differential of the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value.
7. The hybrid power grid phase-commutation converter control method according to claim 6, characterized in that: Methods for determining the DC current command value according to the DC current control target value of the converter, the negative product of the quotient of the droop coefficient and the DC voltage sampling value and the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value, the negative product of the quotient of the AC bus voltage frequency rated value and the DC voltage sampling value and the moment of inertia, and the differential of the difference between the AC bus voltage frequency rated value and the AC bus voltage frequency sampling value include: Among them, I dc_ref is the DC current command value, k f is the droop coefficient, U dc is the DC voltage sampling value, f N is the rated value of the AC bus voltage frequency, f is the sampling value of the AC bus voltage frequency, and J is the moment of inertia; I dcn is the target value for converter DC current control.
8. A computer device comprising a processor, characterized in that: The processor is used to execute a computer program to implement the steps of the hybrid grid-commutated converter control method according to any one of claims 1 to 7.
9. A readable storage medium storing computer executable instructions, characterized in that: The computer executable instructions are used to implement the hybrid grid-commutated converter control method according to any one of claims 1 to 7 when executed.
10. A hybrid power grid phase-commutation converter control device, characterized in that: It includes a thyristor valve commutation module and a modulation voltage instruction generation module; the modulation voltage instruction generation module includes a modulation voltage theoretical value calculation submodule; The thyristor valve commutation module is used to realize that when the commutated bridge arm of the thyristor valve in the commutation converter commutates to the target bridge arm, starting from the opening moment of the target bridge arm at a set time before the moment corresponding to the natural commutation point, the modulation voltage values of the full-bridge sub-module valves in the commutation converter corresponding to the target bridge arm and the commutated bridge arm are all modulation voltage command values within the set time, and are respectively in the same direction and opposite direction to the AC bus voltage; The modulation voltage instruction generation module is used to generate a modulation voltage instruction value including the modulation voltage theoretical value calculated by the modulation voltage theoretical value calculation submodule; The modulation voltage theoretical value calculation submodule is used to obtain the modulation voltage theoretical value according to the product of the primary-to-secondary transformation ratio of the converter transformer and the effective value of the AC bus voltage, the negative of the product of the product and the cosine of the thyristor valve trigger angle, the DC current sampling value and the product of the angular velocity corresponding to the AC bus voltage frequency and the equivalent commutation inductance and the absolute value of the thyristor valve trigger angle.