Power decoupling control method and system based on injection-type grid-commutated converter

Abstract

The present invention provides a power decoupling control method and system based on an injection-type grid-commutated converter, relates to the field of grid-commutated converters, and is applied to an injection-type grid-commutated converter, comprising an upper bridge group and a lower bridge group with the same structure, wherein the upper bridge group and the lower bridge group are connected in parallel on the AC side, and the upper bridge group and the lower bridge group are connected in series at the DC side port, and the upper bridge group comprises an upper bridge LCC thyristor main bridge and an upper bridge shunt module; the method comprises: obtaining an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value of the injection-type grid-commutated converter; determining a trigger angle of the upper bridge group and a trigger angle of the lower bridge group based on the active power reference value, the reactive power reference value, the active power measured value, and the reactive power measured value; generating a trigger signal according to the trigger angle of the upper bridge group, the trigger angle of the lower bridge group, and a trigger constraint set, to control the operation of the injection-type grid-commutated converter, thereby realizing power decoupling control of the injection-type grid-commutated converter.

Description

Technical Field

[0001] The present invention relates to the field of power grid phase-commutation converters, and in particular to a power decoupling control method and system based on an injection-type power grid phase-commutation converter. Background Art

[0002] The Reinjection Line Commutated Converter (RLCC) is a new type of converter based on harmonic injection theory. It aims to improve commutation reliability and optimize power control capabilities through specific technical measures. Existing RLCCs are constructed by cascading a shunt module composed of fully controlled reverse-resistance devices on the DC side of an LCC. Essentially, they are current-source converters, making them fully suitable for HVDC transmission. RLCCs inherently possess the advantages of LCCs for ultra-high power applications. Furthermore, by injecting DC current processed by the shunt module into the LCC, the LCC thyristors achieve zero-current commutation, providing shutdown capability, preventing commutation failures, and enabling leading or lagging power operation. Furthermore, as the DC current waveform injected into the LCC approaches the ideal injection waveform, the AC-side current becomes more sinusoidal, even eliminating the need for external filtering. Compared to LCCs, RLCCs significantly improve commutation failure suppression and current harmonics suppression on both the AC and DC sides.

[0003] Although the shunt module can enable thyristors to have the ability to turn off, existing RLCCs can only control the main bridge trigger angle, resulting in a certain disadvantage in power control flexibility, which limits its development. For example, applying DC voltage control and power factor correction control to a current source converter (CSC) using fully controlled reverse resistance power devices, while capable of high power factor operation, the fundamental frequency modulation means that the CSC using fully controlled power devices only has a single control variable trigger angle, which cannot achieve power decoupling control. By mathematically modeling the CSC and establishing an inner and outer loop control strategy with capacitor voltage as the control target, active and reactive power decoupling control can be achieved. However, due to the influence of the CSC circuit characteristics, the capacitor voltage amplitude and phase will change simultaneously, and the active and reactive power will inevitably be linked, which means that the CSC only has partial decoupling control capabilities.

[0004] Therefore, it is necessary to provide a power decoupling control method and system based on an injection-type grid-commutated converter, so as to realize power decoupling control of the injection-type grid-commutated converter. Summary of the Invention

[0005] The present invention provides a power decoupling control method and system based on an injection-type grid-commutated converter, which is applied to the injection-type grid-commutated converter, wherein the injection-type grid-commutated converter includes an upper bridge group and a lower bridge group, the upper bridge group and the lower bridge group have the same structure, the upper bridge group and the lower bridge group are connected in parallel on the AC side, and the upper bridge group and the lower bridge group are connected in series at the DC side port, and the upper bridge group includes an upper bridge LCC thyristor main bridge and an upper bridge shunt module; the method includes: obtaining an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value of the injection-type grid-commutated converter; determining a trigger angle of the upper bridge group and a trigger angle of the lower bridge group based on the active power reference value, the reactive power reference value, the active power measured value, and the reactive power measured value; generating a trigger signal according to the trigger angle of the upper bridge group, the trigger angle of the lower bridge group, and a trigger constraint set to control the operation of the injection-type grid-commutated converter.

[0006] Furthermore, the method of determining the trigger angle of the upper bridge group and the trigger angle of the lower bridge group based on the active power reference value, the reactive power reference value, the active power measured value and the reactive power measured value includes: determining the active current reference value and the reactive current reference value of the AC side current of the injection-type grid-commutated converter based on the active power reference value, the reactive power reference value, the active power measured value and the reactive power measured value; calculating the first intermediate trigger angle and the second intermediate trigger angle according to the active current reference value and the reactive current reference value of the AC side current of the injection-type grid-commutated converter; and determining the trigger angle of the upper bridge group and the trigger angle of the lower bridge group according to the first intermediate trigger angle and the second intermediate trigger angle.

[0007] Furthermore, the first intermediate trigger angle and the second intermediate trigger angle are calculated based on the following formula:

[0008] ,

[0009] in, is the first intermediate firing angle, is the active current reference value, is the reactive current reference value, is the second intermediate firing angle, is the current modulation coefficient of the upper bridge group and the lower bridge group, is a direct current.

[0010] Furthermore, the trigger angles of the upper bridge group and the lower bridge group are calculated based on the following formula:

[0011] ,

[0012] ,

[0013] in, is the trigger angle of the upper bridge group, is the trigger angle of the lower bridge group.

[0014] Furthermore, the upper bridge shunt module includes a first upper bridge injection branch and a second upper bridge injection branch, and the structure of the first upper bridge injection branch is consistent with that of the second upper bridge injection branch; the upper bridge LCC thyristor main bridge includes an upper bridge Y-bridge thyristor group and an upper bridge D-bridge thyristor group, and the structure of the upper bridge Y-bridge thyristor group is consistent with that of the upper bridge D-bridge thyristor group; the upper bridge first injection branch is electrically connected to the upper bridge Y-bridge thyristor group, and the output end of the upper bridge Y-bridge thyristor group is electrically connected to the Y-type winding of the upper bridge phase-shifting transformer; the upper bridge second injection branch is electrically connected to the upper bridge D-bridge thyristor group, and the output end of the upper bridge D-bridge thyristor group is electrically connected to the D-type winding of the upper bridge phase-shifting transformer.

[0015] Furthermore, the first injection branch of the upper bridge includes a first fully-controlled injection switch, a second fully-controlled injection switch, and a first injection inductor. The first injection inductor is connected to the DC side port of the upper bridge group, and the first fully-controlled injection switch is connected in parallel with the second fully-controlled injection switch. The second injection branch of the upper bridge includes a third fully-controlled injection switch, a fourth fully-controlled injection switch, and a second injection inductor. The second injection inductor is connected to the DC side port of the upper bridge group, and the third fully-controlled injection switch is connected in parallel with the fourth fully-controlled injection switch. The output end of the first fully-controlled injection switch and the output end of the third fully-controlled injection switch are electrically connected to the upper bridge Y-bridge thyristor group, and the output end of the second fully-controlled injection switch and the output end of the fourth fully-controlled injection switch are electrically connected to the upper bridge D-bridge thyristor group. The upper bridge Y-bridge thyristor group includes an upper bridge Y-bridge 6-pulse three-phase bridge.

[0016] Furthermore, the trigger constraint set includes: the thyristor switching frequency of the upper bridge Y-bridge thyristor group and the upper bridge D-bridge thyristor group of the upper bridge LCC thyristor main bridge is 50 Hz, the trigger pulse interval of adjacently numbered thyristor switches in the upper bridge Y-bridge thyristor group is 60°, the trigger pulse interval of adjacently numbered thyristor switches in the upper bridge D-bridge thyristor group is 60°, and the pulse width of the thyristor switches in the upper bridge Y-bridge thyristor group and the upper bridge D-bridge thyristor group is 120°; the trigger pulse interval of thyristor switches with the same serial number in the upper bridge Y-bridge thyristor group and the upper bridge D-bridge thyristor group is 30°, and the thyristor switches in the upper bridge Y-bridge thyristor group lead the thyristor switches with the same serial number in the upper bridge D-bridge thyristor group.

[0017] Furthermore, the trigger constraint set includes: the upper bridge shunt module adopts a seven-level injection form, the switching frequency is 300Hz, and the width of each level is 5°; the switching pulse of the upper bridge shunt module provides a zero level for the upper bridge LCC thyristor main bridge at the natural commutation point.

[0018] Furthermore, the trigger constraint set includes: the first fully-controlled injection switch of the upper bridge Y bridge and the second fully-controlled injection switch of the upper bridge Y bridge of the first injection branch of the upper bridge are complementary turned on; the third fully-controlled injection switch of the upper bridge Y bridge and the fourth fully-controlled injection switch of the upper bridge Y bridge of the second injection branch of the upper bridge are complementary turned on.

[0019] The present invention provides a power decoupling control system based on an injection-type grid-commutated converter, which is used to execute the above-mentioned power decoupling control method based on the injection-type grid-commutated converter, including: a data acquisition module, used to obtain the active power reference value, reactive power reference value, active power measured value and reactive power measured value of the injection-type grid-commutated converter; a parameter determination module, used to determine the trigger angle of the upper bridge group and the trigger angle of the lower bridge group based on the active power reference value, reactive power reference value, active power measured value and reactive power measured value; an operation control module, used to generate a trigger signal according to the trigger angle of the upper bridge group, the trigger angle of the lower bridge group and the trigger constraint set, and control the operation of the injection-type grid-commutated converter.

[0020] Compared with the prior art, the power decoupling control method and system based on the injection-type grid-commutated converter provided by the present invention have at least the following beneficial effects:

[0021] Power decoupling control enables independent adjustment of active and reactive power. By obtaining active and reactive power reference values ​​and comparing them with the measured values, the trigger angles of the upper and lower bridge groups can be adjusted separately, thereby precisely controlling the active and reactive power outputs of the converters to meet the varying power requirements of the power system. For example, when more active power needs to be delivered to the grid, the relevant parameters can be adjusted individually to increase active power output; when the system voltage needs to be adjusted, the reactive power output can be independently controlled. This allows for rapid response to changes in active and reactive power in the system. When the load or power generation conditions of the grid change, the control method can quickly calculate a new trigger angle based on the deviation between the reference and measured values, generating a trigger signal that enables the converter to adjust its output power in a timely manner to maintain the system's power balance.

[0022] By precisely controlling reactive power output, power decoupling control helps maintain stable AC bus voltage. In power grids, reactive power balance is crucial for voltage stability. When reactive power is needed, the converter can promptly provide the required reactive power, preventing voltage fluctuations and voltage collapse, and improving power system voltage stability.

[0023] When a system fault or disturbance occurs, power decoupling control can quickly adjust the converter's output power, providing the necessary power support and helping the system quickly restore stable operation. For example, during a fault, the converter can reduce system power shortfalls and mitigate frequency and voltage fluctuations by adjusting active and reactive power output.

[0024] The LCC thyristor main bridge adopts a parallel LCC structure, inheriting the high power density characteristics of LCC and enabling efficient power conversion. Due to its high power density, the injection-type grid-commutated converter can achieve large-capacity power transmission in a relatively small physical space, making it suitable for space-constrained application scenarios. The injection-type grid-commutated converter further modulates the constant DC current by cascading a shunt module composed of reverse-resistance fully controlled devices on the DC side, making the AC side current harmonics extremely low, close to the output characteristics of MMC. The presence of the shunt module enables the injection-type grid-commutated converter to have four-quadrant operation capabilities, which can flexibly control the transmission of active power and reactive power to meet the different needs of the power grid.

[0025] The shunt module enables the parallel-type LCC main bridge thyristor valves to achieve zero-current shutdown, effectively eliminating the risk of commutation failure. This is particularly important during AC system faults or disturbances, ensuring stable system operation. Suppressing commutation failures improves system reliability and reduces power outages caused by commutation failures.

[0026] Injection-type grid-commutated converters can operate in four quadrants, independently controlling the transmission of active and reactive power, achieving power decoupling. This helps maintain grid voltage stability and power balance. Four-quadrant operation allows injection-type grid-commutated converters to adapt to diverse grid operating conditions, including power generation, consumption, and reactive power compensation.

[0027] By utilizing fully controlled reverse-resistance components, the injection-type grid-commutated converter achieves zero-current shutdown during switching, reducing switching losses and improving overall system efficiency. Zero switching losses translate to lower energy loss and heat generation, reducing system operating and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] This specification will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, like numbers represent like structures, wherein:

[0029] Figure 1 is a flow chart of a power decoupling control method based on an injection-type grid-commutated converter according to some embodiments of this specification;

[0030] Figure 2 is a circuit diagram of an injection-type grid-commutated converter according to some embodiments of this specification;

[0031] Figure 3 is a schematic diagram of the relationship between the AC side voltage and current vectors according to some embodiments of this specification;

[0032] Figure 4 is a power decoupling control block diagram in a rectification state according to some embodiments of this specification;

[0033] Figure 5 is a schematic diagram of a trigger signal timing according to some embodiments of this specification;

[0034] Figure 6 is a diagram illustrating physical quantities related to AC and DC sides according to some embodiments of this specification;

[0035] Figure 7 This is a module diagram of a power decoupling control system based on an injection-type grid-commutated converter according to some embodiments of this specification. DETAILED DESCRIPTION

[0036] To more clearly illustrate the technical solutions of the embodiments of this specification, the following briefly describes the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this specification. Those skilled in the art can apply this specification to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0037] The power decoupling control method based on injection-type grid-commutated converter can be applied to injection-type grid-commutated converter. Figure 2 is a circuit diagram of an injection-type grid-commutated converter according to some embodiments of this specification, such as Figure 2 As shown, the injection-type grid-commutated converter includes an upper bridge group and a lower bridge group. The structures of the upper bridge group and the lower bridge group are consistent. The upper bridge group and the lower bridge group are connected in parallel on the AC side, and the upper bridge group and the lower bridge group are connected in series at the DC side port. The upper bridge group includes an upper bridge LCC thyristor main bridge and an upper bridge shunt module. I dc is the DC current, i rYhj (j = a, b, c) and i rDhj They are the three-phase currents of the Y bridge and the D bridge on the secondary side of the phase-shifting transformer, i rYlj (j = a, b, c) and i rDlj They are the three-phase currents of the Y bridge and the D bridge of the secondary side lower bridge group of the phase-shifting transformer, i rhj is the three-phase AC current of the upper bridge group, i rlj is the three-phase AC current of the lower bridge group,i rj is the AC side current of the injection-type grid-commutated converter. U dcr is the DC side voltage, U dcYh and U dcDh are the DC voltages of the Y bridge and D bridge of the upper bridge group, U dcYl and U dcDl are the DC voltages of the Y bridge and D bridge of the upper bridge group, respectively. The following description will be made using the upper bridge group as an example.

[0038] like Figure 2 As shown, the upper bridge group includes an upper bridge LCC thyristor main bridge and an upper bridge shunt module. The upper bridge shunt module is provided between the upper bridge LCC thyristor main bridge and the AC side port of the upper bridge group. The upper bridge LCC thyristor main bridge includes an upper bridge Y bridge thyristor group ( Figure 2 Valve group T in Yh1 -T Yh6 ) and upper bridge D bridge thyristor group ( Figure 2 Valve group T in Dh1 -T Dh6 ), the upper Y-bridge thyristor group has the same structure as the upper D-bridge thyristor group, T Yh1 -T Yh6 、T Dl1 -T Yl6 All are semi-controlled thyristors. The upper bridge shunt module includes a first injection branch and a second injection branch. The first and second injection branches have the same structure. The first injection branch is electrically connected to the upper bridge Y-bridge thyristor group, the output of which is electrically connected to the Y-type winding of the upper bridge phase-shifting transformer. The second injection branch is electrically connected to the upper bridge D-bridge thyristor group, the output of which is electrically connected to the D-type winding of the upper bridge phase-shifting transformer.

[0039] In some embodiments, the first upper bridge injection branch includes a first upper bridge fully controlled injection switch T Yrh1 , the second fully controlled injection switch T Drh1 And the first injection inductor L h1 The first upper bridge injection inductor is connected to the DC side port of the upper bridge group, the first upper bridge fully controlled injection switch is connected in parallel with the second upper bridge fully controlled injection switch; the second upper bridge injection branch includes the third upper bridge fully controlled injection switch T Yrhn , the fourth fully controlled injection switch T Drhn And the second injection inductor L hn, the second injection inductor of the upper bridge is connected to the DC side port of the upper bridge group, the third fully controlled injection switch of the upper bridge is connected in parallel with the fourth fully controlled injection switch of the upper bridge; the output end of the first fully controlled injection switch of the upper bridge and the output end of the third fully controlled injection switch of the upper bridge are electrically connected to the upper bridge Y bridge thyristor group, the output end of the second fully controlled injection switch of the upper bridge and the output end of the fourth fully controlled injection switch of the upper bridge are electrically connected to the upper bridge D bridge thyristor group; the upper bridge Y bridge thyristor group includes an upper bridge Y bridge 6-pulse three-phase bridge ( Figure 2 Valve group T in Yh1 -T Yh6 ).

[0040] like Figure 2 As shown, the lower bridge group includes a lower bridge LCC thyristor main bridge and a lower bridge shunt module. A lower bridge shunt module is provided between the lower bridge LCC thyristor main bridge and the AC side port of the lower bridge group. The lower bridge LCC thyristor main bridge includes a lower bridge Y bridge thyristor group ( Figure 2 Valve group T in Yl1 -T Yl6 ) and the lower bridge D bridge thyristor group ( Figure 2 Valve group T in Dl1 -T Dl6 The lower bridge shunt module includes a lower bridge first injection branch and a lower bridge second injection branch. The lower bridge first injection branch includes a lower bridge first fully controlled injection switch T Yrl1 , lower bridge second fully controlled injection switch T Drl1 And the first injection inductor L of the lower bridge l1 The second injection branch of the lower bridge includes the third fully controlled injection switch T Yrln , the fourth fully controlled injection switch T Drln And the lower bridge second injection inductor L ln .

[0041] Figure 1 is a flow chart of a power decoupling control method based on an injection-type grid-commutated converter according to some embodiments of this specification, such as Figure 1 As shown, the power decoupling control method based on the injection-type grid-commutated converter may include the following steps.

[0042] Step 110 , obtaining an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value of the injection-type grid-commutated converter.

[0043] Specifically, under the condition of voltage balance of three-phase power grid, take the AC bus voltage phasor U r The direction is the d-axis direction, u rd = U m , u rq = 0,U m is the modulus of the AC bus voltage phasor, then

[0044] ,

[0045] in, is the active power on the AC side, is the reactive power on the AC side, The AC bus voltage is d The component on the axis, The AC side current is d The component on the axis, The AC side current is q Components on the axis.

[0046] The active power measured value and the reactive power measured value can be calculated according to the above formula.

[0047] Step 120 : Determine the trigger angle of the upper bridge group and the trigger angle of the lower bridge group based on the active power reference value, the reactive power reference value, the active power measured value, and the reactive power measured value.

[0048] In some embodiments, step 120 specifically includes:

[0049] Based on the active power reference value, the reactive power reference value, the active power measured value, and the reactive power measured value, the trigger angle of the upper bridge group and the trigger angle of the lower bridge group are determined, including:

[0050] Determining an active current reference value and a reactive current reference value of an AC side current of an injection-type grid-commutated converter based on an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value;

[0051] Calculating a first intermediate firing angle and a second intermediate firing angle according to an active current reference value and a reactive current reference value of an AC side current of the injection-type grid-commutated converter;

[0052] The trigger angle of the upper bridge group and the trigger angle of the lower bridge group are determined according to the first intermediate trigger angle and the second intermediate trigger angle.

[0053] Specifically, Figure 6 is an illustration of the physical quantities related to the AC and DC sides shown in some embodiments of this specification, such as Figure 6 As shown, take the AC bus voltage phasor is the reference phasor, AC bus voltage phasor , upper bridge group, lower bridge group and AC side current phasor of injection type grid commutation converter They are:

[0054] ,

[0055] ,

[0056] ,

[0057] ,

[0058] in, 、 and AC bus a 、 b 、 c The instantaneous value of the three-phase voltage, is the amplitude of the AC bus voltage, is the angular frequency of the AC voltage, is the time variable, is the trigger angle of the upper bridge group, is the trigger angle of the lower bridge group.

[0059] Taking phase A as an example, the AC side current of the injection type grid commutation converter is After calculation, it can be expressed as:

[0060] ,

[0061] AC side current phasor Expressed in polar coordinate form:

[0062] ,

[0063] From the above analysis, we can get the following Figure 3 The AC side voltage and current vector relationship is shown as follows: Figure 3 middle, is the phase angle, is the equivalent resistance, is the equivalent reactance. It can be seen that the AC side current of the injection type grid commutation converter is The amplitude is given by is controlled by control.

[0064] The AC side current of the injection type grid commutated converter can be converted into Transformed into:

[0065] ,

[0066] make , , 、 It can be expressed as:

[0067] ,

[0068] Then we can get 、 The inverse formula is:

[0069] ,

[0070] ,

[0071] in, is the first intermediate firing angle, is the active current reference value, is the reactive current reference value, is the second intermediate firing angle, is the current modulation coefficient of the upper bridge group and the lower bridge group, is a direct current.

[0072] Figure 4 This is a power decoupling control block diagram in the rectification state according to some embodiments of this specification, such as Figure 4 As shown, the PI regulator is based on the active power reference value , reactive power reference value , measured value of active power , maximum d-axis current I d max , minimum d-axis current I d min , maximum q-axis current I q max , minimum q-axis current I q min And the measured value of reactive power Q r(meas) , generates the active current reference value of the AC side current of the injection type grid commutated converter i rdref and reactive current reference value i rqref , and then according to 、 The inverse calculation formula is 、 , and then according to , Calculate the trigger angles of the upper and lower bridge groups to achieve closed-loop control. If operating in inverter mode, the 0° compensation angle can be replaced with 180°.

[0073] Step 130 : Generate a trigger signal according to the trigger angle of the upper bridge group, the trigger angle of the lower bridge group, and the trigger constraint set to control the operation of the injection-type grid-commutated converter.

[0074] In some embodiments, triggering the timing constraints includes:

[0075] The thyristor switching frequency of the upper bridge Y-bridge thyristor group and the upper bridge D-bridge thyristor group of the upper bridge LCC thyristor main bridge is 50Hz, the trigger pulse interval of the adjacent numbered thyristor switches in the upper bridge Y-bridge thyristor group is 60°, the trigger pulse interval of the adjacent numbered thyristor switches in the upper bridge D-bridge thyristor group is 60°, and the pulse width of the thyristor switches in the upper bridge Y-bridge thyristor group and the upper bridge D-bridge thyristor group is 120°;

[0076] The trigger pulse interval of the thyristor switches with the same serial number in the upper Y-bridge thyristor group and the upper D-bridge thyristor group is 30°, and the thyristor switches in the upper Y-bridge thyristor group lead the thyristor switches with the same serial number in the upper D-bridge thyristor group;

[0077] The upper bridge shunt module adopts a seven-level injection form with a switching frequency of 300Hz and a width of 5° for each level. For the injection of seven levels, each switch of the upper bridge shunt module traverses all the set switch states within a 360° cycle.

[0078] The switching pulse of the upper bridge shunt module provides a zero level for the upper bridge LCC thyristor main bridge at the natural commutation point, ensuring that the upper bridge LCC thyristor main bridge can achieve zero current shutdown;

[0079] The first fully controlled injection switch of the upper bridge Y bridge and the second fully controlled injection switch of the upper bridge Y bridge of the first injection branch of the upper bridge are complementary turned on;

[0080] The third fully-controlled injection switch of the upper bridge Y bridge and the fourth fully-controlled injection switch of the upper bridge Y bridge of the second injection branch of the upper bridge are complementary turned on. At the same time, only one fully-controlled injection switch of an injection branch can be turned on.

[0081] The trigger timing constraints of the lower bridge group are the same as above and will not be repeated here.

[0082] Figure 5 is a schematic diagram of the trigger signal timing according to some embodiments of this specification, such as Figure 5 As shown in the figure, both the upper bridge group and the lower bridge group are triggered in this way, and the trigger angle of the upper bridge group and the trigger angle of the lower bridge group are used for control respectively. The dual control variables can realize power decoupling control. The grid commutation converter based on thyristor of the rectifier station can be used Figure 5 The trigger signal timing is modulated as shown in the figure. Indicates the trigger signal of the * switch, for example, for The trigger signal, for trigger signal.

[0083] Figure 7is a module diagram of a power decoupling control system based on an injection-type grid-commutated converter according to some embodiments of this specification, such as Figure 7 As shown, the power decoupling control system based on the injection-type grid-commutated converter may include a data acquisition module, a parameter determination module and an operation control module.

[0084] A data acquisition module is used to obtain an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value of an injection-type grid-commutated converter;

[0085] A parameter determination module, configured to determine a trigger angle of an upper bridge group and a trigger angle of a lower bridge group based on an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value;

[0086] The operation control module is used to generate a trigger signal according to the trigger angle of the upper bridge group, the trigger angle of the lower bridge group and the trigger constraint set to control the operation of the injection-type grid-commutated converter.

[0087] The power decoupling control system based on the injection-type grid-commutated converter can be used to execute the power decoupling control method based on the injection-type grid-commutated converter, which will not be described in detail here.

[0088] Finally, it should be understood that the embodiments described in this specification are intended only to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly described and illustrated in this specification.

Claims

1. A power decoupling control method based on an injection-type grid-commutated converter, characterized in that: Applied to an injection-type grid-commutated converter, wherein the injection-type grid-commutated converter includes an upper bridge group and a lower bridge group, the upper bridge group and the lower bridge group have the same structure, the upper bridge group and the lower bridge group are connected in parallel on the AC side, and the upper bridge group and the lower bridge group are connected in series on the DC side port, and the upper bridge group includes an upper bridge LCC thyristor main bridge and an upper bridge shunt module; The method comprises: Obtaining an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value of an injection-type grid-commutated converter; Determine the trigger angle of the upper bridge group and the trigger angle of the lower bridge group based on the active power reference value, the reactive power reference value, the active power measured value, and the reactive power measured value; Generate a trigger signal based on the trigger angle of the upper bridge group, the trigger angle of the lower bridge group, and the trigger constraint set to control the operation of the injection-type grid-commutated converter; The trigger angle of the upper bridge group and the trigger angle of the lower bridge group are determined based on the active power reference value, the reactive power reference value, the active power measured value, and the reactive power measured value, including: Determining an active current reference value and a reactive current reference value of an AC side current of an injection-type grid-commutated converter based on an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value; Calculating a first intermediate firing angle and a second intermediate firing angle according to an active current reference value and a reactive current reference value of an AC side current of the injection-type grid-commutated converter; Determine the trigger angle of the upper bridge group and the trigger angle of the lower bridge group according to the first intermediate trigger angle and the second intermediate trigger angle; The first intermediate firing angle and the second intermediate firing angle are calculated based on the following formula: ， in, is the first intermediate firing angle, is the active current reference value, is the reactive current reference value, is the second intermediate firing angle, is the current modulation coefficient of the upper bridge group and the lower bridge group, is a direct current; The trigger angles of the upper and lower bridge groups are calculated based on the following formulas: ， ， in, is the trigger angle of the upper bridge group, is the trigger angle of the lower bridge group.

2. The power decoupling control method based on injection-type grid-commutated converter according to claim 1, characterized in that: The upper bridge shunt module includes a first upper bridge injection branch and a second upper bridge injection branch, and the first upper bridge injection branch and the second upper bridge injection branch have the same structure; The upper LCC thyristor main bridge includes an upper Y-bridge thyristor group and an upper D-bridge thyristor group, and the upper Y-bridge thyristor group has the same structure as the upper D-bridge thyristor group; The first injection branch of the upper bridge is electrically connected to the upper bridge Y-bridge thyristor group, and the output end of the upper bridge Y-bridge thyristor group is electrically connected to the Y-type winding of the upper bridge phase-shifting transformer; The second injection branch of the upper bridge is electrically connected to the D-bridge thyristor group of the upper bridge, and the output end of the D-bridge thyristor group of the upper bridge is electrically connected to the D-type winding of the upper bridge phase-shifting transformer.

3. The power decoupling control method based on injection-type grid-commutated converter according to claim 2, characterized in that: The first injection branch of the upper bridge includes a first fully-controlled injection switch of the upper bridge, a second fully-controlled injection switch of the upper bridge, and a first injection inductor of the upper bridge. The first injection inductor of the upper bridge is connected to the DC side port of the upper bridge group. The first fully-controlled injection switch of the upper bridge is connected in parallel with the second fully-controlled injection switch of the upper bridge. The second injection branch of the upper bridge includes a third fully-controlled injection switch of the upper bridge, a fourth fully-controlled injection switch of the upper bridge, and a second injection inductor of the upper bridge. The second injection inductor of the upper bridge is connected to the DC side port of the upper bridge group. The third fully-controlled injection switch of the upper bridge is connected in parallel with the fourth fully-controlled injection switch of the upper bridge. The output end of the first fully-controlled injection switch of the upper bridge and the output end of the third fully-controlled injection switch of the upper bridge are electrically connected to the upper bridge Y-bridge thyristor group, and the output end of the second fully-controlled injection switch of the upper bridge and the output end of the fourth fully-controlled injection switch of the upper bridge are electrically connected to the upper bridge D-bridge thyristor group; The upper Y-bridge thyristor group includes an upper Y-bridge 6-pulse three-phase bridge.

4. The power decoupling control method based on injection-type grid-commutated converter according to claim 3, characterized in that: Generate a trigger signal based on the trigger angle of the upper bridge group, the trigger angle of the lower bridge group, and the trigger constraint set to control the operation of the injection-type grid-commutated converter; The trigger constraint set includes: The thyristor switching frequency of the upper bridge Y-bridge thyristor group and the upper bridge D-bridge thyristor group of the upper bridge LCC thyristor main bridge is 50Hz, the trigger pulse interval of the adjacent numbered thyristor switches in the upper bridge Y-bridge thyristor group is 60°, the trigger pulse interval of the adjacent numbered thyristor switches in the upper bridge D-bridge thyristor group is 60°, and the pulse width of the thyristor switches in the upper bridge Y-bridge thyristor group and the upper bridge D-bridge thyristor group is 120°; The trigger pulse interval of the thyristor switches with the same serial number in the upper Y-bridge thyristor group and the upper D-bridge thyristor group is 30°, and the thyristor switches in the upper Y-bridge thyristor group are ahead of the thyristor switches with the same serial number in the upper D-bridge thyristor group.

5. The power decoupling control method based on injection-type grid-commutated converter according to claim 4, characterized in that: Generate a trigger signal based on the trigger angle of the upper bridge group, the trigger angle of the lower bridge group, and the trigger constraint set to control the operation of the injection-type grid-commutated converter; The injection-type grid-commutated converter includes an upper bridge group and a lower bridge group. The upper bridge group and the lower bridge group have the same structure. The upper bridge group and the lower bridge group are connected in parallel on the AC side, and the upper bridge group and the lower bridge group are connected in series on the DC side port. The upper bridge group includes an upper bridge LCC thyristor main bridge and an upper bridge shunt module. The trigger constraint set includes: The upper bridge shunt module adopts a seven-level injection form, the switching frequency is 300Hz, and the width of each level is 5°; The switching pulse of the upper bridge shunt module provides a zero level for the upper bridge LCC thyristor main bridge at the natural commutation point.

6. The power decoupling control method based on injection-type grid-commutated converter according to claim 5, characterized in that: Generate a trigger signal based on the trigger angle of the upper bridge group, the trigger angle of the lower bridge group, and the trigger constraint set to control the operation of the injection-type grid-commutated converter; The upper bridge shunt module includes a first upper bridge injection branch and a second upper bridge injection branch, and the first upper bridge injection branch and the second upper bridge injection branch have the same structure; The trigger constraint set includes: The first fully controlled injection switch of the upper bridge Y bridge and the second fully controlled injection switch of the upper bridge Y bridge of the first injection branch of the upper bridge are complementary turned on; The third fully-controlled injection switch of the upper bridge Y-bridge of the second injection branch of the upper bridge and the fourth fully-controlled injection switch of the upper bridge Y-bridge are complementarily turned on.

7. A power decoupling control system based on an injection-type grid-commutated converter, characterized in that: A method for controlling a power decoupling device based on an injection-type grid-commutated converter according to any one of claims 1 to 6, comprising: A data acquisition module is used to obtain an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value of an injection-type grid-commutated converter; A parameter determination module, configured to determine a trigger angle of an upper bridge group and a trigger angle of a lower bridge group based on an active power reference value, a reactive power reference value, an active power measured value, and a reactive power measured value; The operation control module is used to generate a trigger signal according to the trigger angle of the upper bridge group, the trigger angle of the lower bridge group and the trigger constraint set to control the operation of the injection-type grid-commutated converter.

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