Alternating current voltage drop control method, device and system of converter and storage medium

Abstract

The invention provides an alternating-current voltage drop control method, device and system of a converter and a storage medium. The method comprises the steps that whether three-phase alternating current is in a drop state or not is judged according to sampling parameters; if the three-phase alternating current is in a falling state, acquiring an output parameter of the matrix circuit according to the sampling parameter, and outputting a plurality of first target driving signals according to the output parameter of the matrix circuit; and / or, the input voltage of the full-bridge circuit is obtained according to the output parameters of the matrix circuit, and a plurality of second target driving signals are generated according to the input voltage of the full-bridge circuit; controlling a corresponding first target switch tube to be turned on or turned off according to the first target driving signal, and / or controlling a corresponding second target switch tube to be turned on or turned off according to the second target driving signal, so that the inductance current polarity meets the expectation when the matrix circuit performs high and low level switching, and the problem of high voltage spike caused by voltage drop is avoided.

Description

Technical Field

[0001] This application relates to the field of integrated circuit technology, and in particular to an AC voltage drop control method, apparatus, system and storage medium for a converter. Background Technology

[0002] Power electronic converters, as core devices for the conversion and control of electrical energy forms, play an indispensable role in modern industry, new energy power generation, smart grids, and electric vehicles. Their basic function is to precisely control electrical parameters such as voltage, current, frequency, and phase through the periodic switching of power semiconductor switching devices, thereby converting one form of electrical energy into another to meet the specific power demands of various loads. Among numerous converter topologies, the matrix converter exhibits unique technological advantages, becoming a highly anticipated new type of direct AC-AC conversion scheme. Compared to traditional indirect converters based on the DC link (such as AC-DC-AC converters), the matrix converter eliminates the need for large and short-lived DC energy storage electrolytic capacitors. The core of the matrix converter is a power matrix composed of nine bidirectional switches. These bidirectional switches are typically composed of two fully controlled power devices connected in antiparallel, enabling them to block bidirectional voltage and conduct bidirectional current.

[0003] In actual operation, when the input AC voltage drops, the output of the matrix converter rapidly decreases. Without control, due to the bidirectional blocking characteristics of the bidirectional switches in the matrix circuit, when the inductor current has no freewheeling path, energy in the inductor will transfer to the junction capacitance of the switches. This can easily lead to unexpected inductor current polarity, resulting in high voltage spikes on the switches and jeopardizing the stable operation of the converter. Therefore, it is necessary to improve the existing technology to solve these problems. Summary of the Invention

[0004] This application provides an AC voltage sag control method, apparatus, system, and storage medium for a converter. The method can effectively control the voltage sag of the converter and avoid high voltage spikes caused by the voltage sag.

[0005] In a first aspect, this application provides an AC voltage sag control method for a converter, the converter including a matrix circuit, an isolation transformer, and a full-bridge circuit, the matrix circuit being connected to the primary side of the isolation transformer, and the full-bridge circuit being connected to the secondary side of the isolation transformer, the matrix circuit being used to connect three-phase AC power; the matrix circuit and the full-bridge circuit are each provided with multiple switching transistors; the AC voltage sag control method includes: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, and it is determined whether the three-phase AC power is in a drop state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power. If the three-phase AC power is in a drop state, the output voltage of the matrix circuit is obtained according to the sampling parameters, and multiple first target drive signals are output according to the output voltage of the matrix circuit; and / or, the input voltage of the full-bridge circuit is obtained according to the output voltage of the matrix circuit, and multiple second target drive signals are generated according to the input voltage of the full-bridge circuit. The first target switch is turned on or off according to the first target drive signal, and / or the second target switch is turned on or off according to the second target drive signal, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching, wherein the first target switch is the switch on the matrix circuit, and the second target switch is the switch on the full-bridge circuit.

[0006] As a preferred embodiment, after the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the three-phase AC power is judged to be in a slump state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; The absolute voltage value of each phase is generated based on the instantaneous voltage value of each phase, and the sum of the absolute voltage values ​​of the three phases is generated based on the absolute voltage values ​​of each phase. If the sum of the absolute values ​​of the three-phase voltages is less than a preset first threshold value, then the three-phase AC power is determined to be in a drop state.

[0007] As a preferred embodiment, the theoretical three-phase voltage values ​​are generated based on the rated effective values ​​of each phase of the three-phase AC power. A first difference is generated based on the sum of the theoretical three-phase voltage values ​​and the absolute values ​​of the three-phase voltages. If the first difference is greater than a preset second threshold value, it is determined that the three-phase AC power is in a drop state.

[0008] As a preferred embodiment, after the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the three-phase AC power is judged to be in a slump state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; The corresponding theoretical instantaneous voltage value is generated based on the rated effective voltage value of each phase of the three-phase AC power, and the second difference value of each phase is generated based on the instantaneous voltage value of each phase and the corresponding theoretical instantaneous voltage value. If the second difference value corresponding to at least one phase of the three-phase alternating current is greater than the third threshold value of the preset value, then the three-phase alternating current is determined to be in a drop state.

[0009] As a preferred embodiment, after the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the three-phase AC power is judged to be in a slump state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; Calculate the instantaneous values ​​of the line voltages of the three-phase AC power supply based on the instantaneous values ​​of the phase voltages. Determine the sector number currently in operation of the matrix circuit, wherein the sector is divided into 12 sectors based on the αβ coordinate system; Based on the sector number, the first line voltage corresponding to the high vector and the second line voltage corresponding to the low vector are obtained from a predefined line voltage correspondence table, wherein the line voltage correspondence table defines the line voltage combination corresponding to the high vector and the low vector in each sector; The sum is calculated based on the instantaneous values ​​of the first and second line voltages; The sum is compared with a preset threshold. When the sum is lower than the preset threshold, it is determined that the three-phase AC power is in a drop state.

[0010] As a preferred embodiment, controlling the corresponding first target switch to turn on or off according to the first target driving signal includes: According to the first target driving signal, the corresponding first target switch is controlled to be turned on or off, thereby increasing the first shift ratio and / or decreasing the second shift ratio, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching. Wherein, taking the rising edge of the positive level of the output waveform of the matrix circuit as the time reference, the first shift ratio is defined as the ratio of the first delay time of the rising edge of the positive level of the input waveform of the full bridge circuit relative to the time reference to half a switching cycle time; the second shift ratio is defined as the ratio of the second delay time of the falling edge of the positive level of the input waveform of the full bridge circuit relative to the time reference to half a switching cycle time.

[0011] As a preferred embodiment, controlling the corresponding first target switch to turn on or off according to the first target driving signal includes: A first shift ratio and a second shift ratio are obtained, wherein the rising edge of the positive level of the output voltage waveform of the matrix circuit is used as the time reference. The first shift ratio is defined as the ratio of a first delay time of the rising edge of the positive level of the input voltage waveform of the full-bridge circuit relative to the time reference to half a switching cycle time. The second shift ratio is defined as the ratio of a second delay time of the falling edge of the positive level of the input voltage waveform of the full-bridge circuit relative to the time reference to half a switching cycle time. Obtain the high-level duty cycle and low-level duty cycle of the output voltage waveform of the matrix circuit, wherein the high-level duty cycle is defined as the ratio of the duration of the high-level vector in the positive half-cycle to half a switching cycle time, and the low-level duty cycle is defined as the ratio of the duration of the low-level vector in the positive half-cycle to half a switching cycle time. The high-level duty cycle and the low-level duty cycle are adjusted according to the first target driving signal, such that the relationship between the high-level duty cycle, the low-level duty cycle, the first shift ratio, and the second shift ratio satisfies the following formula:

[0012] in, Indicates the high-level duty cycle. Indicates the low-level duty cycle. Indicates the first move compared to, This indicates the second shift compared to the previous one.

[0013] As a preferred embodiment, adjusting the high-level duty cycle according to the first target driving signal includes: The turn-off timing of each switch in the second switch group is controlled according to the second target driving signal, so that the turn-off time of the first switch group is advanced compared to the original time, thereby reducing the high-level duty cycle. The second switch group consists of multiple first target switches that constitute the high-level vector conduction in the matrix circuit.

[0014] As a preferred embodiment, adjusting the low-level duty cycle according to the first target driving signal includes: The turn-off timing of each switch in the third switch group is controlled according to the second target drive signal, so that the turn-off time of the second switch group is delayed compared with the original time, thereby increasing the low-level duty cycle; wherein, the third switch group is a plurality of the first target switches that constitute the low-level vector conduction in the matrix circuit.

[0015] Secondly, this application provides an AC voltage sag control device for a converter, the converter including a matrix circuit, an isolation transformer, and a full-bridge circuit, the matrix circuit being connected to the primary side of the isolation transformer, and the full-bridge circuit being connected to the secondary side of the isolation transformer, the matrix circuit being used to connect three-phase AC power; the matrix circuit and the full-bridge circuit are each provided with multiple switching transistors; the AC voltage sag control device includes: The acquisition module is used to acquire sampling parameters of the three-phase AC power after the matrix circuit is connected to the three-phase AC power, and to determine whether the three-phase AC power is in a drop state based on the sampling parameters, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; The control module is configured to, if the three-phase AC power is in a drop state, obtain the output parameters of the matrix circuit according to the sampling parameters, and output a plurality of first target drive signals according to the output parameters of the matrix circuit; and / or, obtain the input parameters of the full-bridge circuit according to the output parameters of the matrix circuit, and generate a plurality of second target drive signals according to the input parameters of the full-bridge circuit, wherein the output parameters include output voltage and the input parameters include input voltage; The output module is used to control the corresponding first target switch to be turned on or off according to the first target driving signal, and / or to control the corresponding second target switch to be turned on or off according to the second target driving signal, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching, wherein the first target switch is the switch on the matrix circuit, and the second target switch is the switch on the full-bridge circuit.

[0016] Thirdly, this application provides an AC voltage sag control system for a converter, including a converter and a controller electrically connected to the converter, wherein: The converter includes a matrix circuit, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect to three-phase AC power. The matrix circuit and the full-bridge circuit are each equipped with multiple switching transistors. The controller is used to execute the steps in the AC voltage sag control method of the converter.

[0017] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a controller, it implements the steps in the AC voltage drop control method of the converter.

[0018] The beneficial effects of the technical solutions provided in some embodiments of this application include at least the following: This application obtains sampling parameters of the three-phase AC power and determines whether the three-phase AC power is in a voltage drop state based on the sampling parameters. If the three-phase AC power is in a voltage drop state, the output parameters of the matrix circuit are obtained based on the sampling parameters, and multiple first target drive signals are output based on the output parameters of the matrix circuit. Alternatively, the input parameters of the full-bridge circuit are obtained based on the output parameters of the matrix circuit, and multiple second target drive signals are generated based on the input parameters of the full-bridge circuit. The first target drive signals are used to control the corresponding first target switch to turn on or off, and / or the second target drive signals are used to control the corresponding second target switch to turn on or off, so that the polarity of the inductor current conforms to expectations when the matrix circuit performs high-low level switching, thereby avoiding high-voltage spikes caused by voltage drops. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a converter provided in an embodiment of this application.

[0021] Figure 2 This is a basic flowchart illustrating an AC voltage sag control method for a converter provided in an embodiment of this application.

[0022] Figure 3 This is a 12-sector partitioning diagram based on the αβ coordinate system provided in the embodiments of this application.

[0023] Figure 4 This is provided by the embodiments of this application. , , A schematic diagram of the waveform associated with voltage drop.

[0024] Figure 5 This is provided by the embodiments of this application. , , A schematic diagram of the waveform associated with the normal state.

[0025] Figure 6 This is the adjusted version provided in this embodiment. , , Schematic diagram of associated waveforms; Figure 7This is a schematic diagram of the program module of an AC voltage drop control device for a converter provided in an embodiment of this application. Detailed Implementation

[0026] To make the inventive objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] In the description of the embodiments of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0029] In the embodiments of this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0030] To address the issue of high voltage spikes caused by voltage dips in converters in related technologies, the first embodiment of this application provides an AC voltage dip control system for a converter, including a converter and a controller. The converter and the controller are electrically connected, and the controller is used to implement the AC voltage dip control method for the converter.

[0031] Specifically, the converter in this embodiment can be a matrix-dual active bridge AC / DC converter. The matrix-dual active bridge AC / DC converter has a simplified circuit structure and a low-impedance current path. The primary-side matrix circuit can efficiently convert the three-phase power frequency input into a volt-second balanced high-frequency AC square wave, which is sent to the primary side of the isolation transformer. In conjunction with the secondary-side full-bridge circuit, it performs phase-shift control similar to that of a DC / DC dual active bridge, achieving the effects of output voltage regulation and input power factor correction (PFC).

[0032] In some embodiments of this example, the converter includes an LC filter, a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit includes three arms, each arm containing two bidirectional switches connected in series, each bidirectional switch consisting of two anti-parallel series-connected switching transistors. The two ends of each arm of the matrix circuit are connected to the primary side of the isolation transformer via an inductor. The three-phase AC power, after passing through the LC filter, is connected to the midpoints of the three arms of the matrix circuit. The midpoints of the arms of the full-bridge circuit are connected to the secondary side of the isolation transformer. The two ends of the full-bridge circuit are connected to an output capacitor and then to an external load or battery.

[0033] Reference Figure 1 As shown, in some embodiments of this example, the LC filter includes capacitors and inductors. That is, the converter includes three AC-side inductors, three AC-side capacitors, a matrix circuit, an isolation transformer, a full-bridge circuit, an output capacitor, and a load. The matrix circuit has three arms. One end of each of the three AC-side inductors is connected to a three-phase AC power supply port, and the other end of each of the three AC-side inductors is connected to the midpoint of the three arms of the matrix circuit via the three AC-side capacitors.

[0034] In some embodiments of this example, a switching transistor S is provided in the full-bridge circuit. 13 S 14 S 15 S 16 Switch S 13 The emitter and the switch S 14 The collectors of the transistors are connected as one arm of a bridge, and the midpoint of this arm is connected to one end of the secondary side of the isolation transformer; the switching transistor S 15 The emitter and the switch S 16 The collectors of the transistors are connected as one bridge arm, and the midpoint of this bridge arm is connected to the other end of the secondary side of the isolation transformer; the switching transistor S 13 collector and switch S 15 The collector of the transistor is connected to the positive DC side node of the full-bridge circuit and one end of the output capacitor Co. The switching transistor S 14 The emitter and the switch S 16 The emitter is connected to the negative DC side node of the full-bridge circuit and connected to the other end of the output capacitor Co. The output capacitor Co can also be connected to the load R.

[0035] In some embodiments of this example, the matrix circuit also includes multiple switching transistors S. ap S bp S cp S an S bn S cn Each switching transistor consists of two switching transistors connected together, that is, S ap Including switching transistors S1 and S2, S bp Including switching transistors S5 and S6, S cp Including switching transistors S9 and S 10 S an Including switching transistors S3 and S4, S bn Including switching transistors S7 and S8, S cn Including the switching transistor S 11 and S 12 AC side inductor L a With the switching transistor S ap Connection; AC side inductor L b With the switching transistor S bp Connection; AC side inductor L c With the switching transistor S bp Connection; Switch S ap Connected to one end of the primary winding of the isolation transformer; switch S an Connect to the other end of the primary winding of the isolation transformer; switch S bp Connected to one end of the primary winding of the isolation transformer, the switching transistor S bn Connect to the other end of the primary winding of the isolation transformer; switch S cp Connected to one end of the primary winding of the isolation transformer, the switching transistor S cn Connect to the other end of the primary side of the isolation transformer.

[0036] It should be understood that, in some embodiments, placing the inductor on the primary or secondary side of the converter circuit does not affect the converter's operating principle. Therefore, changing the inductor's position does not affect the implementation of the return power suppression method in this embodiment. Similarly, using a common-source or common-drain connection for the bidirectional switch in the matrix circuit does not affect the converter's operating principle. Therefore, changing the bidirectional switch's connection method does not affect the implementation of the return power suppression method in this embodiment.

[0037] The second embodiment of this application provides an AC voltage sag control method for a converter, used to control high voltage spikes caused by voltage sags. For ease of explanation, please refer to... Figure 2 As shown, the output voltage of the matrix circuit is defined as... The input voltage of the full-bridge circuit is defined as follows: The current flowing through an inductor is defined as .

[0038] The AC voltage sag control method for the converter includes the following steps: Step S100: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, and it is determined whether the three-phase AC power is in a drop state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power.

[0039] Please refer to Figure 4 As shown, Figure 4 (a) is a waveform diagram of the three-phase AC voltage before the voltage drop. The polarity of the inductor current at the level switching moments is as expected. Figure 4 (b) is a waveform diagram of the three-phase AC voltage drop after the voltage drop. A significant voltage drop has occurred, and the polarity of the inductor current at the high-to-low switching point no longer meets expectations, leading to a significant high-voltage spike during the switching process.

[0040] In this embodiment, by acquiring the sampling parameters of the three-phase AC power, it is determined in advance whether the three-phase AC power is in a slump state, thereby controlling the converter in a corresponding manner to reduce the inductor current. The polarity meets expectations, avoiding high voltage spikes.

[0041] Step S200: If the three-phase AC power is in a drop state, then the output parameters of the matrix circuit are obtained according to the sampling parameters, and multiple first target drive signals are output according to the output parameters of the matrix circuit; and / or, the input parameters of the full-bridge circuit are obtained according to the output parameters of the matrix circuit, and multiple second target drive signals are generated according to the input parameters of the full-bridge circuit, wherein the output parameters include output voltage and output voltage waveform, and the input parameters include input voltage and input voltage waveform; In this embodiment, when a voltage dip is detected in the three-phase AC voltage, the key variable characterizing the voltage dip, namely the output voltage of the matrix circuit, is calculated based on the sampling parameters. The output voltage waveform is used to generate a first target drive signal to control the switching transistors on the matrix circuit. Simultaneously, the input parameters of the full-bridge circuit can be further derived from the output parameters of the matrix circuit, and a second target drive signal is generated based on these input parameters to control the switching transistors on the full-bridge circuit.

[0042] Step S300: Control the corresponding first target switch to turn on or off according to the first target drive signal, and / or control the corresponding second target switch to turn on or off according to the second target drive signal, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching, wherein the first target switch is the switch on the matrix circuit, and the second target switch is the switch on the full-bridge circuit.

[0043] By using both the first target drive signal and the second target drive signal, precise timing intervention can be performed on the switching transistors in the circuit, either one or both, effectively enriching the control methods and making the control strategy more flexible.

[0044] With the above settings, voltage spikes can be proactively prevented, rather than passively absorbed or protected after the fact. This ensures the safe and stable operation of the converter itself during power grid transient faults, avoids overvoltage damage to the switching transistors, and maintains continuous power transmission.

[0045] In one embodiment of this example, after the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and it is determined whether the three-phase AC power is in a slump state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: Step S111: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power.

[0046] In this step, refer to Figure 1 As shown, let the effective value of the phase voltage of the three-phase AC power be... V rms The instantaneous values ​​of the three-phase AC voltages are as follows:

[0047]

[0048]

[0049] in, The instantaneous voltage value of the first phase of a three-phase alternating current. The instantaneous voltage value of the second phase of the three-phase alternating current. θ represents the instantaneous voltage of the third phase of a three-phase alternating current, and θ is the angle variable.

[0050] Step S112: Generate the absolute voltage value of each phase based on the instantaneous voltage value of each phase, and generate the sum of the absolute voltage values ​​of the three phases based on the absolute voltage values ​​of each phase; Step S113: If the sum of the absolute values ​​of the three-phase voltages is less than a preset first threshold value, then it is determined that the three-phase AC power is in a drop state; In one embodiment of this example, after the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and it is determined whether the three-phase AC power is in a slump state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: Step S114: Generate theoretical three-phase voltage values ​​based on the rated effective values ​​of each phase of the three-phase AC power. Step S115: Generate a first difference based on the sum of the theoretical three-phase voltage values ​​and the absolute values ​​of the three-phase voltages. If the first difference is greater than a preset second threshold value, then determine that the three-phase AC power is in a drop state.

[0051] In one embodiment of this invention, after the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the three-phase AC power is judged to be in a slump state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: Step S121: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; Step S122 generates the corresponding theoretical instantaneous voltage value based on the rated effective voltage value of each phase of the three-phase AC power, and generates the second difference value of each phase based on the instantaneous voltage value of each phase and the corresponding theoretical instantaneous voltage value. Step S123: If the second difference value corresponding to at least one phase of the three-phase AC power is greater than the third threshold value of the preset value, then it is determined that the three-phase AC power is in a drop state.

[0052] In one embodiment of this example, please refer to Figure 5 As shown, when the circuit is operating normally, the output voltage of the matrix circuit is... The voltage waveform is changed from high level ( v 1, v 3), low level ( v 2, v 4) and zero level constitute. Within one switching cycle Ts, to ensure the volt-second balance of the magnetic device, The voltage waveform is symmetrical in both positive and negative directions.

[0053] Using the rising edge of the positive level of the output voltage waveform of the matrix circuit as the time reference, the first shift ratio in the rectification direction is defined. D 1 compared to the second move D 2. The first shift ratio D1 is defined as the ratio of the first delay time of the positive level rising edge of the secondary voltage of the isolation transformer relative to the time reference, to half a switching cycle time; the second delay ratio is... D 2 is defined as the ratio of the second delay time of the positive level falling edge of the secondary voltage of the isolation transformer relative to the time reference to half a switching cycle time.

[0054] In one embodiment of this example, controlling the corresponding first target switch to turn on or off according to the first target driving signal includes: Based on the first target drive signal, the corresponding first target switch is controlled to turn on or off, thereby increasing the first shift ratio and / or decreasing the second shift ratio, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching. Furthermore, the conduction timing of each switch in the matrix circuit is controlled according to the first target driving signal, so that the conduction time of the matrix circuit is advanced compared to the original time, thereby increasing the first shift ratio; And / or, according to the first target driving signal, control the turn-off timing of each switch in the matrix circuit, so that the turn-off time of the matrix circuit is advanced compared to the original time, thereby reducing the second shift ratio.

[0055] Furthermore, the conduction timing of each switch in the full-bridge circuit is controlled according to the second target drive signal, so that the conduction time of the lagging bridge arm in the full-bridge circuit is further delayed, thereby increasing the first shift ratio.

[0056] And / or, according to the second target drive signal, control the turn-on timing of each switch in the full-bridge circuit, so that the turn-on time of the leading bridge arm in the full-bridge circuit is further advanced, thereby reducing the second shift ratio.

[0057] In one embodiment of this example, please refer to... Figure 3 As shown, a spatial vector diagram of the converter is constructed based on the magnitudes of adjacent vectors and the phase voltage values ​​in the three-phase AC power, and the spatial vector diagram is divided into 12 small sectors. After the matrix circuit is connected to the three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the presence or absence of a voltage drop in the three-phase AC power is determined based on these sampling parameters. The sampling parameters include the instantaneous values ​​of the phase voltages of the three-phase AC power, including: S131: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; S132: Calculate the instantaneous values ​​of the line voltages of the three-phase AC power based on the instantaneous values ​​of the phase voltages; S133 determines the sector number currently in operation of the matrix circuit, the sector being divided into 12 sectors based on the αβ coordinate system; S134: Based on the sector number, obtain the first line voltage corresponding to the high vector and the second line voltage corresponding to the low vector from the predefined line voltage correspondence table, wherein the line voltage correspondence table defines the line voltage combination corresponding to the high vector and the low vector in each sector; S135: Calculate the sum based on the instantaneous values ​​of the first and second line voltages; S136: Compare the sum with a preset threshold. When the sum is lower than the preset threshold, determine that the three-phase AC power is in a drop state.

[0058] Table 1 shows the line voltages corresponding to v1~v4 in different sectors. It can be noted that v PN It exhibits a cyclical change of "high level - low level - zero level - negative high level - negative low level - zero level".

[0059] Table 1:

[0060] Please refer to Figure 5 As shown, with A voltage greater than zero indicates the positive half-cycle of the switching cycle. A voltage less than zero occurs during the negative half-cycle of the switching cycle. The high-level duty cycle is... The low-level duty cycle is The zero-level duty cycle is =1 It should be noted that, due to The voltage waveform is symmetrical, so the duty cycle here is relative to half a switching cycle.

[0061] The high-level duty cycle Defined as: high level during the positive half-cycle Vector (or negative half-cycle high level) The ratio of the duration of the vector to half a switching cycle; The low-level duty cycle Defined as: low level during the positive half-cycle Vector (or negative half-cycle) The ratio of the duration of the vector to half a switching cycle.

[0062] The step of controlling the corresponding first target switch to turn on or off according to the first target driving signal includes: S250: Obtain a first shift ratio and a second shift ratio, wherein, with the rising edge of the positive level of the output voltage waveform of the matrix circuit as the time reference, the first shift ratio is defined as the ratio of a first delay time of the rising edge of the positive level of the input voltage waveform of the full-bridge circuit relative to the time reference to half a switching cycle time; the second shift ratio is defined as the ratio of a second delay time of the falling edge of the positive level of the input voltage waveform of the full-bridge circuit relative to the time reference to half a switching cycle time. S260: Obtain the high-level duty cycle and low-level duty cycle of the output voltage waveform of the matrix circuit; S270: Adjust the high-level duty cycle and the low-level duty cycle according to the first target driving signal, so that the relationship between the high-level duty cycle, the low-level duty cycle, the first shift ratio, and the second shift ratio satisfies the following formula: ; in, Indicates the high-level duty cycle. Indicates the low-level duty cycle. Indicates the first move compared to, This indicates the second shift compared to the previous one.

[0063] Please refer to Figure 6 As shown, it illustrates the result after adjusting the above data and satisfying the above formula. , , The waveform.

[0064] In one embodiment of this example, adjusting the high-level duty cycle according to the first target driving signal includes: S280: Control the turn-off timing of each switch in the second switch group according to the second target drive signal, so that the turn-off time of the first switch group is advanced compared to the original time, thereby reducing the high-level duty cycle. The second switch group consists of multiple first target switches in the matrix circuit that constitute the high-level vector conduction. In one embodiment of this example, adjusting the low-level duty cycle according to the first target driving signal includes: S290: Control the turn-off timing of each switch in the third switch group according to the second target drive signal, so that the turn-off time of the second switch group is delayed compared with the original time, thereby increasing the low-level duty cycle; wherein, the third switch group is a plurality of the first target switches that constitute the low-level vector conduction in the matrix circuit.

[0065] In this embodiment, by increasing the first shift ratio , reduce the second shift compared Increase the first displacement compared to Simultaneously reduce the second shift ratio To control the circuit, or adjust the high-level duty cycle. and low level duty cycle The relationship between the circuit and the inductor current polarity at the level switching moment is controlled by the above methods, thereby eliminating the voltage spikes caused by the voltage drop on the AC side of the converter.

[0066] It should be noted that the first switch group, the second switch group, and the third switch group are not composed of fixed switch groups, but are each composed of certain switch groups that meet specific conditions at a certain time.

[0067] The third embodiment of this application provides an AC voltage sag control device for a converter. This AC voltage sag control device can be applied to the aforementioned AC voltage sag control method. The converter includes a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer through the inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect three-phase AC power. The matrix circuit and the full-bridge circuit are each equipped with multiple switching transistors. The AC voltage sag control device includes: The acquisition module 401 is used to acquire the sampling parameters of the three-phase AC power after the matrix circuit is connected to the three-phase AC power, and to determine whether the three-phase AC power is in a drop state based on the sampling parameters, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; The control module 402 is configured to, if the three-phase AC power is in a drop state, obtain the output parameters of the matrix circuit according to the sampling parameters, and output a plurality of first target drive signals according to the output parameters of the matrix circuit; and / or, obtain the input parameters of the full-bridge circuit according to the output parameters of the matrix circuit, and generate a plurality of second target drive signals according to the input parameters of the full-bridge circuit, wherein the output parameters include output voltage and output voltage waveform, and the input parameters include input voltage and input voltage waveform; Output module 403 is used to control the corresponding first target switch to be turned on or off according to the first target driving signal, and / or control the corresponding second target switch to be turned on or off according to the second target driving signal, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching, wherein the first target switch is the switch on the matrix circuit, and the second target switch is the switch on the full-bridge circuit.

[0068] In some embodiments of this example, the acquisition module 401 is further configured to: after the matrix circuit is connected to three-phase AC power, acquire sampling parameters of the three-phase AC power, wherein the sampling parameters include the instantaneous voltage values ​​of each phase of the three-phase AC power; generate absolute voltage values ​​of each phase based on the instantaneous voltage values ​​of each phase, and generate the sum of the absolute voltage values ​​of the three phases based on the absolute voltage values ​​of each phase; if the sum of the absolute voltage values ​​of the three phases is less than a preset first threshold value, then determine that the three-phase AC power is in a drop state; generate theoretical three-phase voltage values ​​based on the rated effective values ​​of each phase of the three-phase AC power; generate a first difference based on the theoretical three-phase voltage values ​​and the sum of the absolute voltage values ​​of the three phases, and if the first difference is greater than a preset second threshold value, then determine that the three-phase AC power is in a drop state.

[0069] In some embodiments of this example, the acquisition module 401 is further configured to acquire sampling parameters of the three-phase AC power after the matrix circuit is connected to the three-phase AC power, wherein the sampling parameters include the instantaneous voltage values ​​of each phase of the three-phase AC power; generate corresponding theoretical instantaneous voltage values ​​based on the rated effective voltage values ​​of each phase of the three-phase AC power; generate a second difference value for each phase based on the instantaneous voltage values ​​of each phase and the corresponding theoretical instantaneous voltage values; if the second difference value corresponding to at least one phase of the three-phase AC power is greater than a preset third threshold value, then it is determined that the three-phase AC power is in a drop state.

[0070] In some embodiments of this example, the acquisition module 401 is further configured to acquire sampling parameters of the three-phase AC power after the matrix circuit is connected to the three-phase AC power, wherein the sampling parameters include the instantaneous values ​​of the phase voltages of the three-phase AC power; calculate the instantaneous values ​​of the line voltages of the three-phase AC power based on the instantaneous values ​​of the phase voltages; determine the sector number currently operating in the matrix circuit, wherein the sector is divided into 12 sectors based on the αβ coordinate system; acquire the first line voltage corresponding to the high vector and the second line voltage corresponding to the low vector from a predefined line voltage correspondence table based on the sector number, wherein the line voltage correspondence table defines the line voltage combination corresponding to the high vector and the low vector in each sector; calculate the sum based on the instantaneous values ​​of the first line voltage and the second line voltage; compare the sum with a preset threshold, and determine that the three-phase AC power is in a drop state when the sum is lower than the preset threshold.

[0071] In some embodiments of this example, the acquisition module 402 is further configured to acquire a first shift ratio and a second shift ratio, wherein, with the rising edge of the positive level of the output voltage waveform of the matrix circuit as the time reference, the first shift ratio is defined as the ratio of a first delay time of the rising edge of the positive level of the input voltage waveform of the full-bridge circuit relative to the time reference to half a switching cycle time; the second shift ratio is defined as the ratio of a second delay time of the falling edge of the positive level of the input voltage waveform of the full-bridge circuit relative to the time reference to half a switching cycle time; the high-level duty cycle and the low-level duty cycle of the output voltage waveform of the matrix circuit are acquired; and the high-level duty cycle and the low-level duty cycle are adjusted according to the first target driving signal so that the relationship between the high-level duty cycle, the low-level duty cycle, the first shift ratio, and the second shift ratio satisfies the following formula:

[0072] in, Indicates the high-level duty cycle. Indicates the low-level duty cycle. Indicates the first move compared to, This indicates the second shift compared to the previous one.

[0073] In some embodiments of this example, the acquisition module 402 is further configured to control the turn-off timing of each switch in the first switch group according to the second target driving signal, so that the turn-off time of the first switch group is advanced compared to the original time, thereby reducing the high-level duty cycle. The first switch group consists of multiple first target switches in the matrix circuit that constitute positive level conduction.

[0074] In some embodiments of this example, the acquisition module 402 is further configured to control the turn-off timing of each switch in the second switch group according to the second target driving signal, so that the turn-off time of the second switch group is delayed compared to the original time, thereby increasing the low-level duty cycle; wherein, the second switch group is a plurality of the first target switches that constitute the negative level conduction in the matrix circuit.

[0075] The fourth embodiment of this application provides an AC voltage sag control system for a converter. This AC voltage sag control system can be used to implement the AC voltage sag control method for the converter in the foregoing embodiments, and mainly includes: A converter and a controller electrically connected to the converter; the controller can be configured with a memory, a controller, and a computer program stored in the memory and executable on the controller, the memory and the controller being communicatively connected. When the controller executes the computer program, it implements the method described in Embodiment 2 above. The number of controllers can be one or more.

[0076] The memory can be high-speed random access memory (RAM) or non-volatile memory, such as disk storage. The memory is used to store executable program code, and the controller is coupled to the memory.

[0077] Furthermore, embodiments of this application also provide a computer-readable storage medium, which may be disposed in the AC voltage drop control system of the aforementioned converter, and the computer-readable storage medium may be the memory in the foregoing embodiments.

[0078] The computer-readable storage medium stores a computer program that, when executed by the controller, implements the return power suppression method of the converter in the aforementioned embodiments. Furthermore, the computer-readable storage medium can also be a USB flash drive, external hard drive, read-only memory (ROM), RAM, magnetic disk, or optical disk, or any other medium capable of storing program code.

[0079] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0080] The modules described as separate components may or may not be physically separate. Similarly, the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0081] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0082] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned readable storage medium includes various media capable of storing program code, such as USB flash drives, external hard drives, ROM, RAM, magnetic disks, or optical disks.

[0083] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0084] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0085] The above is a description of the AC voltage drop control method, apparatus, system and readable storage medium of the converter provided in this application. For those skilled in the art, based on the ideas of the embodiments of this application, there will be changes in the specific implementation and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for controlling AC voltage sag in a converter, characterized in that, The converter includes a matrix circuit, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect three-phase AC power. The matrix circuit and the full-bridge circuit are each equipped with multiple switching transistors; The AC voltage sag control method includes: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, and it is determined whether the three-phase AC power is in a drop state based on the sampling parameters. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power. If the three-phase AC power is in a drop state, the output parameters of the matrix circuit are obtained according to the sampling parameters, and multiple first target drive signals are output according to the output parameters of the matrix circuit; and / or, the input parameters of the full-bridge circuit are obtained according to the output parameters of the matrix circuit, and multiple second target drive signals are generated according to the input parameters of the full-bridge circuit, wherein the output parameters include output voltage, and the input parameters include input voltage; The first target switch is turned on or off according to the first target drive signal, and / or the second target switch is turned on or off according to the second target drive signal, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching, wherein the first target switch is the switch on the matrix circuit, and the second target switch is the switch on the full-bridge circuit.

2. The AC voltage sag control method for the converter according to claim 1, characterized in that, After the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the three-phase AC power is used to determine whether it is in a voltage drop state. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; The absolute voltage value of each phase is generated based on the instantaneous voltage value of each phase, and the sum of the absolute voltage values ​​of the three phases is generated based on the absolute voltage values ​​of each phase. If the sum of the absolute values ​​of the three-phase voltages is less than a preset first threshold value, then the three-phase AC power is determined to be in a drop state.

3. The AC voltage sag control method for the converter according to claim 1, characterized in that, After the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the three-phase AC power is used to determine whether it is in a voltage drop state. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: The theoretical three-phase voltage values ​​are generated based on the rated effective values ​​of each phase of the three-phase AC power. A first difference is generated based on the sum of the theoretical three-phase voltage values ​​and the absolute values ​​of the three-phase voltages. If the first difference is greater than a preset second threshold value, it is determined that the three-phase AC power is in a drop state.

4. The AC voltage sag control method for the converter according to claim 1, characterized in that, After the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the three-phase AC power is used to determine whether it is in a voltage drop state. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; The corresponding theoretical instantaneous voltage value is generated based on the rated effective voltage value of each phase of the three-phase AC power, and the second difference value of each phase is generated based on the instantaneous voltage value of each phase and the corresponding theoretical instantaneous voltage value. If the second difference value corresponding to at least one phase of the three-phase alternating current is greater than the third threshold value of the preset value, then the three-phase alternating current is determined to be in a drop state.

5. The AC voltage sag control method for the converter according to claim 1, characterized in that, After the matrix circuit is connected to three-phase AC power, sampling parameters of the three-phase AC power are acquired, and the three-phase AC power is used to determine whether it is in a voltage drop state. The sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power, including: After the matrix circuit is connected to three-phase AC power, the sampling parameters of the three-phase AC power are obtained, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; Calculate the instantaneous values ​​of the line voltages of the three-phase AC power supply based on the instantaneous values ​​of the phase voltages. Determine the sector number currently in operation of the matrix circuit, wherein the sector is divided into 12 sectors based on the αβ coordinate system; Based on the sector number, the first line voltage corresponding to the high vector and the second line voltage corresponding to the low vector are obtained from a predefined line voltage correspondence table, wherein the line voltage correspondence table defines the line voltage combination corresponding to the high vector and the low vector in each sector; The sum is calculated based on the instantaneous values ​​of the first and second line voltages; The sum is compared with a preset threshold. When the sum is lower than the preset threshold, it is determined that the three-phase AC power is in a drop state.

6. The AC voltage sag control method for the converter according to any one of claims 1-5, characterized in that, The step of controlling the corresponding first target switch to turn on or off according to the first target driving signal includes: According to the first target driving signal, the corresponding first target switch is controlled to be turned on or off, thereby increasing the first shift ratio and / or decreasing the second shift ratio, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching. Wherein, taking the rising edge of the positive level of the output waveform of the matrix circuit as the time reference, the first shift ratio is defined as the ratio of the first delay time of the rising edge of the positive level of the input waveform of the full bridge circuit relative to the time reference to half a switching cycle time; the second shift ratio is defined as the ratio of the second delay time of the falling edge of the positive level of the input waveform of the full bridge circuit relative to the time reference to half a switching cycle time.

7. The AC voltage sag control method for the converter according to any one of claims 1-5, characterized in that, The step of controlling the corresponding first target switch to turn on or off according to the first target driving signal includes: A first shift ratio and a second shift ratio are obtained, wherein the rising edge of the positive level of the output voltage waveform of the matrix circuit is used as the time reference. The first shift ratio is defined as the ratio of a first delay time of the rising edge of the positive level of the input voltage waveform of the full-bridge circuit relative to the time reference to half a switching cycle time. The second shift ratio is defined as the ratio of a second delay time of the falling edge of the positive level of the input voltage waveform of the full-bridge circuit relative to the time reference to half a switching cycle time. Obtain the high-level duty cycle and low-level duty cycle of the output voltage waveform of the matrix circuit, wherein the high-level duty cycle is defined as the ratio of the duration of the high-level vector in the positive half-cycle to half a switching cycle time, and the low-level duty cycle is defined as the ratio of the duration of the low-level vector in the positive half-cycle to half a switching cycle time. The high-level duty cycle and the low-level duty cycle are adjusted according to the first target driving signal, such that the relationship between the high-level duty cycle, the low-level duty cycle, the first shift ratio, and the second shift ratio satisfies the following formula: ； in, Indicates the high-level duty cycle. Indicates the low-level duty cycle. Indicates the first move compared to, This indicates the second shift compared to the previous one.

8. The AC voltage sag control method for the converter according to claim 7, characterized in that, The step of adjusting the high-level duty cycle according to the first target driving signal includes: The turn-off timing of each switch in the first switch group is controlled according to the second target driving signal, so that the turn-off time of the first switch group is advanced compared to the original time, thereby reducing the high-level duty cycle. The first switch group consists of multiple first target switches in the matrix circuit that constitute the high-level vector conduction.

9. The AC voltage sag control method for the converter according to claim 7, characterized in that, The step of adjusting the low-level duty cycle according to the first target driving signal includes: The turn-off timing of each switch in the first switch group is controlled according to the first target driving signal, so that the turn-off time of the second switch group is delayed compared with the original time, thereby increasing the low-level duty cycle; wherein, the third switch group is a plurality of the first target switches that constitute the low-level vector conduction in the matrix circuit.

10. An AC voltage sag control device for a converter, characterized in that, The converter includes a matrix circuit, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect three-phase AC power. The matrix circuit and the full-bridge circuit are each equipped with multiple switching transistors; The AC voltage sag control device includes: The acquisition module is used to acquire sampling parameters of the three-phase AC power after the matrix circuit is connected to the three-phase AC power, and to determine whether the three-phase AC power is in a drop state based on the sampling parameters, wherein the sampling parameters include the instantaneous values ​​of the voltage of each phase of the three-phase AC power; The control module is configured to, if the three-phase AC power is in a drop state, obtain the output parameters of the matrix circuit according to the sampling parameters, and output a plurality of first target drive signals according to the output parameters of the matrix circuit; and / or, obtain the input parameters of the full-bridge circuit according to the output parameters of the matrix circuit, and generate a plurality of second target drive signals according to the input parameters of the full-bridge circuit, wherein the output parameters include output voltage and the input parameters include input voltage; The output module is used to control the corresponding first target switch to be turned on or off according to the first target driving signal, and / or to control the corresponding second target switch to be turned on or off according to the second target driving signal, so that the polarity of the inductor current conforms to the expectation when the matrix circuit performs high-low level switching, wherein the first target switch is the switch on the matrix circuit, and the second target switch is the switch on the full-bridge circuit.

11. An AC voltage sag control system for a converter, characterized in that, Includes a converter and a controller electrically connected to the converter, wherein: The converter includes a matrix circuit, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect to three-phase AC power. The matrix circuit and the full-bridge circuit are each equipped with multiple switching transistors. The controller is used to perform the steps in the method of any one of claims 1 to 9.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the controller, it implements the steps of the method according to any one of claims 1 to 9.

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