Single-stage bidirectional AC-DC converter control method, device, terminal and medium

Abstract

The present application discloses a single-stage bidirectional AC-DC converter control method, device, terminal and medium. The solution provided by the present application calculates the β-axis orthogonal current based on the input voltage, input current, filter capacitor voltage relationship equation and orthogonal current relationship equation on the AC grid side of the single-stage bidirectional AC-DC converter. At the same time, the circuit is controlled by a PI controller with the aid of a current decoupling equation without differential terms. The present application solves the problem of the difference in dynamic response speed in constructing β-axis orthogonal current in the prior art. In addition, the present application uses a decoupling equation without differential terms to achieve decoupling of current, further reducing the complexity of the control method and improving the robustness of the system.

Description

Technical Field

[0001] The present application relates to the technical field of converters, and in particular to a single-stage bidirectional AC-DC converter control method, device, terminal and medium. Background Art

[0002] The single-stage bidirectional AC-DC converter has the characteristics of bidirectional power transmission, high power density, controllable AC side power factor, and electrical isolation. The bidirectional single-stage isolated AC-DC matrix converter topology currently used in bidirectional charging devices is as follows: Figure 1 shown.

[0003] The commonly used control methods for bidirectional single-stage isolated AC-DC matrix converters are: one is to use a PR (Proportional resonance) controller to directly control the grid current in a stationary reference coordinate system. The PR controller has a simple structure and is easy to implement. It can achieve zero-static error tracking of the AC given signal, but the controller is sensitive to grid voltage frequency disturbances; the other is to transform the coordinates of the sinusoidal current and use a PI (Proportional integral) controller to control it in a synchronous reference coordinate system. In a synchronous dq coordinate system, the method based on PI regulation can not only achieve independent control of active current and reactive current, but also achieve zero-static error control of the input current. Therefore, this application also uses a PI controller to control the circuit.

[0004] However, since the single-phase system has only one degree of freedom, Clark transformation and Park transformation cannot be performed directly. and input current As the voltage and current components of the α-axis and ,Then The β-axis voltage can be obtained through the phase-locked loop , while the β-axis current component It is usually generated through a delay link. This method has poor dynamic response, which in turn affects the dynamic response speed of the entire system. Summary of the invention

[0005] The present application provides a single-stage bidirectional AC-DC converter control method, device, terminal and medium, which are used to solve the technical problem of slow dynamic response speed of existing single-stage bidirectional AC-DC converters.

[0006] In order to solve the above technical problems, the first aspect of the present application provides a single-stage bidirectional AC-DC converter control method, which is applied to a single-stage bidirectional AC-DC converter. The single-stage bidirectional AC-DC converter includes: an LC filter circuit, a matrix conversion circuit, a high-frequency transformer, an LCL resonant circuit, an H-bridge circuit and an output filter circuit. The control method includes:

[0007] According to the input voltage and input current of the grid side of the single-stage bidirectional AC-DC converter and the equivalent circuit of the grid side of the single-stage bidirectional AC-DC converter, combined with Kirchhoff's law, a circuit parameter relationship model of the equivalent circuit is constructed, and the circuit parameter relationship model includes: a KVL equation and a KCL equation of the equivalent circuit;

[0008] The circuit parameter relationship model is converted into a dq coordinate system, and a filter capacitor voltage relationship equation in the dq coordinate system is constructed in combination with a preset switching cycle and an input current reference value;

[0009] Determining a β-axis voltage relationship equation of the equivalent circuit according to the circuit parameter relationship model, and then performing Laplace transformation on the β-axis voltage relationship equation to obtain an orthogonal current relationship equation of the equivalent circuit;

[0010] The actual input voltage and actual input current of the grid side of the single-stage bidirectional AC-DC converter are collected, and the β-axis orthogonal current is obtained by combining the filter capacitor voltage relationship equation and the orthogonal current relationship equation. The β-axis orthogonal current is used to determine the control parameters of the H-bridge circuit in combination with the preset current decoupling equation and the control parameter calculation equation.

[0011] Preferably, the filter capacitor voltage relationship equation is specifically:

[0012]

[0013] In the formula, , are the d-axis component and the q-axis component of the filter capacitor voltage in the equivalent circuit, , are the d-axis component and the q-axis component of the input voltage, is the equivalent inductance of the equivalent circuit, , are the d-axis component and q-axis component of the input current, , are the d-axis component and the q-axis component of the input current reference value, is the angular frequency of the input voltage, is the equivalent resistance of the equivalent circuit.

[0014] Preferably, the orthogonal current relationship equation is specifically:

[0015]

[0016] In the formula, is the β-axis orthogonal current, is the β-axis component of the input voltage, is the β-axis component of the filter capacitor voltage, is the equivalent inductance of the equivalent circuit, is the Laplace operator.

[0017] Preferably, the current decoupling equation is specifically:

[0018]

[0019] In the formula, , is the d-axis component and q-axis component of the decoupling current, is the equivalent capacitance of the equivalent circuit, , are the d-axis component and the q-axis component of the filter capacitor voltage in the equivalent circuit, is the Laplace operator, is the equivalent inductance of the equivalent circuit, , are the d-axis component and q-axis component of the input current, is the equivalent resistance of the equivalent circuit.

[0020] Preferably, the current decoupling equation is specifically:

[0021]

[0022] In the formula, , is the d-axis component and q-axis component of the decoupling current, is the angular frequency of the input voltage, is the equivalent capacitance of the equivalent circuit, , are the d-axis component and the q-axis component of the filter capacitor voltage in the equivalent circuit, is the Laplace operator, is the equivalent inductance of the equivalent circuit, , are the d-axis component and the q-axis component of the input current.

[0023] Preferably, the control parameter includes: a duty cycle of the H-bridge output voltage.

[0024] Preferably, the control parameter calculation equation is specifically:

[0025]

[0026] Where d is the duty cycle, is the voltage value of the DC voltage source, is the switching angular frequency, m is the amplitude coefficient of the sine function, is the phase coefficient of the sine function, L is the inductance of the LCL resonant circuit, is the q-axis component of the reference value of the matrix converter input current after decoupling in the dq coordinate system, It is the d-axis component of the reference value of the matrix converter input current after decoupling in the dq coordinate system.

[0027] At the same time, the second aspect of the present application provides a single-stage bidirectional AC-DC converter control device, which is applied to a single-stage bidirectional AC-DC converter, wherein the single-stage bidirectional AC-DC converter includes: an LC filter circuit, a matrix conversion circuit, a high-frequency transformer, an LCL resonant circuit, an H-bridge circuit and an output filter circuit, and the control device includes:

[0028] A circuit parameter relationship determination unit, configured to construct a circuit parameter relationship model of the equivalent circuit according to an input voltage and an input current on the grid side of a single-stage bidirectional AC-DC converter and an equivalent circuit on the grid side of the single-stage bidirectional AC-DC converter, in combination with Kirchhoff's law, wherein the circuit parameter relationship model includes: a KVL equation and a KCL equation of the equivalent circuit;

[0029] A first relationship equation conversion unit, used to convert the circuit parameter relationship model into a dq coordinate system, and construct a filter capacitor voltage relationship equation in the dq coordinate system in combination with a preset switching cycle and an input current reference value;

[0030] A second relationship equation conversion unit is used to determine the β-axis voltage relationship equation of the equivalent circuit according to the circuit parameter relationship model, and then perform Laplace transformation on the β-axis voltage relationship equation to obtain the orthogonal current relationship equation of the equivalent circuit;

[0031] The orthogonal current determination unit is used to collect the actual input voltage and actual input current of the grid side of the single-stage bidirectional AC-DC converter, and obtain the β-axis orthogonal current by combining the filter capacitor voltage relationship equation and the orthogonal current relationship equation. The β-axis orthogonal current is used to determine the control parameters of the H-bridge circuit in combination with the preset current decoupling equation and the control parameter calculation equation.

[0032] A third aspect of the present application provides a single-stage bidirectional AC-DC converter control terminal, comprising: a memory and a processor;

[0033] The memory is used to store a program code corresponding to a single-stage bidirectional AC-DC converter control method provided in the first aspect of the present application;

[0034] The processor is used for reading and executing the program code.

[0035] The fourth aspect of the present application provides a computer-readable storage medium, in which a program code corresponding to a single-stage bidirectional AC-DC converter control method as provided in the first aspect of the present application is stored. When the program code is executed by a processor, a single-stage bidirectional AC-DC converter control method as provided in the first aspect of the present application is implemented.

[0036] It can be seen from the above technical solutions that this application has the following advantages:

[0037] The solution provided by the present application first constructs a circuit parameter relationship model of the equivalent circuit based on the equivalent circuit on the AC grid side of a single-stage bidirectional AC-DC converter in combination with Kirchhoff's law, and then constructs the filter capacitor voltage relationship equation and the orthogonal current relationship equation in the dq coordinate system based on the circuit parameter relationship model. Then, by using the collected actual input voltage and actual input current, the β-axis orthogonal current can be obtained by combining the filter capacitor voltage relationship equation and the orthogonal current relationship equation, thereby realizing the construction of an accurate β-axis orthogonal current with faster efficiency. Moreover, the solution of the present application is not limited by the dynamic response speed of the delay link, and can better avoid the influence of the voltage fluctuation on the grid side on the actual constructed β-axis orthogonal current, solving the problem of the difference in the dynamic response speed of the β-axis orthogonal current in the prior art. In addition, the present application adopts a decoupling equation without differential terms to realize the decoupling of the current, further reducing the complexity of the control method and improving the robustness of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0039] Figure 1 This is a single-stage bidirectional AC-DC converter circuit topology diagram.

[0040] Figure 2 It is the waveform diagram of the matrix converter output voltage and the H-bridge output voltage.

[0041] Figure 3 This is a simplified model diagram of the LCL resonant cavity of a single-stage bidirectional AC-DC converter.

[0042] Figure 4 It is the current and voltage phase diagram of the LCL resonant cavity.

[0043] Figure 5 A schematic flow chart of an embodiment of a single-stage bidirectional AC-DC converter control method provided in the present application.

[0044] Figure 6 A logic block diagram of an embodiment of a single-stage bidirectional AC-DC converter control method provided in the present application.

[0045] Figure 7 It is the grid-side equivalent circuit diagram of a single-stage bidirectional AC-DC converter.

[0046] Figure 8 A single-stage bidirectional AC-DC converter control method provided in the present application is constructed Logic block diagram of shaft current.

[0047] Fig. 9 A logic block diagram of current decoupling in a single-stage bidirectional AC-DC converter control method provided in the present application.

[0048] Fig.10 Grid-side voltage and grid-side current waveforms under different current conditions.

[0049] Fig.11 A single-stage bidirectional AC-DC converter control method provided in the present application is constructed Schematic diagram of the effect of shaft current.

[0050] Fig.12 A schematic structural diagram of an embodiment of a single-stage bidirectional AC-DC converter control device provided in the present application.

[0051] Fig.13 A schematic diagram of the structure of a single-stage bidirectional AC-DC converter control terminal embodiment provided in the present application. DETAILED DESCRIPTION

[0052] The present application provides a single-stage bidirectional AC-DC converter control method, device, terminal and medium, which are used to solve the technical problem of slow dynamic response speed of existing single-stage bidirectional AC-DC converters.

[0053] In order to make the purpose, features, and advantages of the invention of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described below are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0054] First, a detailed description of an embodiment of a single-stage bidirectional AC-DC converter control method provided by the present application is as follows:

[0055] This method is applied to a single-stage bidirectional AC-DC converter. The structure of this type of single-stage bidirectional AC-DC converter can be found in Figure 1 , including: LC filtering circuit, matrix conversion circuit, high-frequency transformer, LCL resonant circuit, H-bridge circuit and output filtering circuit.

[0056] In the figure, is an AC voltage source, is a DC voltage source, and the output voltage of the matrix converter is , the DC side full-bridge converter output voltage is recorded as . Let the switching frequencies of the switches on both sides be the same, recorded as , the corresponding switching period is recorded as The input current on the AC side is , the DC side output current is , Input current to the matrix converter.

[0057] Definition of AC side voltage is formula (1), where is the amplitude, is the angular frequency.

[0058] (1)

[0059] In the matrix converter, this embodiment applies a pulse signal with a duty cycle of 50% to drive it, so that it generates a square wave signal with alternating positive and negative pulses and a fixed width. Then it acts on the LCL resonant cavity through an isolation transformer. Since the switching cycle frequency is much greater than the AC voltage source frequency, it can be considered that within one switching cycle The output voltage of the matrix converter is constant. Waveform Figure 2 As shown, Figure 2 (a) and Figure 2 (b) in the figure shows the voltage waveforms when the grid-side voltage is in the positive half cycle and the negative half cycle respectively.

[0060] On the DC side, in this embodiment, and as well as and An internal phase shift is introduced between the two, thus generating a three-level ( ,0, ) AC voltage , whose absolute value is fixed at The width varies quasi-sinusoidally with time. and Add a phase shift angle ,when >0, power is transmitted forward. <0 enables reverse power transfer. Output voltage of full-bridge converter like Figure 2 As shown, Figure 2 (a) and Figure 2 (b) in the figure shows the voltage waveforms when the grid-side voltage is in the positive half cycle and the negative half cycle respectively.

[0061] right and Fourier series expansion is performed to obtain equations (2) and (3), where d is duty cycle.

[0062] (2)

[0063] (3)

[0064] The voltage acting on the left side of the LCL resonant cavity after passing through the high-frequency transformer with a turns ratio of 1:n is The simplified model of the LCL resonant cavity is as follows: Figure 3 Assuming that the LCL resonant cavity can filter out high-frequency harmonics, this embodiment only needs to consider the fundamental component. and In formula 4, V is the current in one switching cycle. Instantaneous value.

[0065] (4)

[0066] (5)

[0067] When the resonant cavity parameters satisfy equation (6), we can obtain and The phase currents are respectively expressed as equation (7) and equation (8). , , and The phase diagram ( and They are and The fundamental component of Figure 4 shown.

[0068] (6)

[0069] (7)

[0070] (8)

[0071] Depend on Figure 4 As for equations (4), (5), (7) and (8), it is easy to see that = hour, and In phase, and In the same phase, the effective value of the current is the minimum when the topology transmits the same power. = hour, and Phase Difference , this time it is the inverter mode, and energy is transferred from the DC side to the AC side.

[0072] right The average input current in the entire switching cycle after passing through the LC filter circuit can be obtained by integrating and averaging within half a switching cycle. As shown in formula (9) (where ). From formula (9), we can know that when the turns ratio n, inductance value L, DC voltage and the switching angular frequency Average input current at a certain time Phase shift angle And duty cycle d control. To reduce current stress, this embodiment in this application fixes the phase shift angle for or .

[0073] (9)

[0074] Since the switching period is much smaller than the period of the AC voltage, the value calculated by equation (9) can be approximately regarded as the instantaneous value of the input current. This embodiment assumes that when the input current changes according to equation (10), the PF value of the bidirectional AC-DC converter is 1. The value range of m is [-1, 1].

[0075] (10)

[0076] By setting the right side of equation (9) equal to the right side of equation (10), we can get the calculation formula of d as equation (11).

[0077] (11)

[0078] See also Figure 5 and Figure 6 , this embodiment provides a single-stage bidirectional AC-DC converter control method, including:

[0079] Step 101: construct a circuit parameter relationship model of the equivalent circuit according to the input voltage and input current of the grid side of the single-stage bidirectional AC-DC converter and the equivalent circuit of the grid side of the single-stage bidirectional AC-DC converter in combination with Kirchhoff's law;

[0080] The circuit parameter relationship model includes: the KVL equation and the KCL equation of the equivalent circuit.

[0081] It should be noted that the grid-side equivalent circuit diagram is as follows: Figure 7 As shown. and is the grid-side input voltage and current, is the internal resistance of the inductor of the LC filter circuit, is the input current of the matrix converter. Kirchhoff’s voltage law and Kirchhoff’s current law give equation (12), where Capacitor Voltage across both ends.

[0082] (12)

[0083] Step 102: convert the circuit parameter relationship model to the dq coordinate system, and construct a filter capacitor voltage relationship equation in the dq coordinate system in combination with a preset switching cycle and an input current reference value;

[0084] It should be noted that according to formula (12), the KCL and KVL equations in the αβ coordinate system can be obtained:

[0085] (13)

[0086] Transforming equation (13) to the dq coordinate system yields:

[0087] (14)

[0088] From equation (14), the voltage across the filter capacitor can be obtained: and They are:

[0089] (15)

[0090] Will (in is the switching cycle, Substituting (for reference current value) into formula (15) yields:

[0091] (16)

[0092] Step 103, determining the β-axis voltage relationship equation of the equivalent circuit according to the circuit parameter relationship model, and then performing Laplace transformation on the β-axis voltage relationship equation to obtain the orthogonal current relationship equation of the equivalent circuit;

[0093] It should be noted that, from equation (12), the voltage equation of the grid-side equivalent circuit on the β axis is:

[0094] (17)

[0095] In actual use The value of is relatively small. In order to speed up the calculation, this embodiment can The terms are omitted and simplified to:

[0096] (18)

[0097] By Laplace transforming equation (18), we can obtain the orthogonal current , the expression is as follows:

[0098] (19)

[0099] Step 104, collect the actual input voltage and actual input current of the grid side of the single-stage bidirectional AC-DC converter, and obtain the β-axis orthogonal current by combining the filter capacitor voltage relationship equation and the orthogonal current relationship equation. The β-axis orthogonal current is used to determine the control parameters of the H-bridge circuit in combination with the preset current decoupling equation and the control parameter calculation equation.

[0100] It should be noted that, from formula (19), the orthogonal current The value of the LC filter inductor If it is known, only the β-axis component of the grid-side voltage and the β-axis component of the voltage across the capacitor Combining equation (16) and equation (19), this embodiment can construct the orthogonal current , constructing orthogonal current The logic block diagram can be found in Figure 8 .

[0101] like Figure 6 As shown, the orthogonal current After that, we can combine the and , converted to the dq coordinate system through Park transformation, we get and Then, Laplace transform is performed on equation (14):

[0102] (20)

[0103] From formula (20), we get:

[0104] (twenty one)

[0105] in, is the d-axis component of the input current of the matrix converter in the dq coordinate system before decoupling, is the q-axis component of the input current of the matrix converter in the dq coordinate system before decoupling. It can be seen from equation (21) that there is cross coupling between the d-axis and q-axis currents. In order to achieve independent control of the d-axis current and the q-axis current, this embodiment needs to add a decoupling equation. When the input voltage is stable, this embodiment can know and The fixed value will not Axis and The cross coupling caused by shaft current can be obtained from equation (21) as follows:

[0106] (twenty two)

[0107] However, the above decoupling equation obviously contains differential terms, which is difficult to implement using a digital controller. Therefore, this embodiment can obtain a new decoupling equation (23) by combining equations (20) and (22), as shown in Fig. 9 The decoupling logic block diagram shown in FIG. 1 shows a decoupling logic block diagram. There is no differential term in the decoupling equation, which can be more easily implemented using a digital controller.

[0108] (twenty three)

[0109] From equation (21) and equation (23), we can get equation (24):

[0110] (twenty four)

[0111] in, is the d-axis component of the reference value of the matrix converter input current after decoupling in the dq coordinate system, is the q-axis component of the reference value of the matrix converter input current after decoupling in the dq coordinate system. and , combined with formula (11) and The calculation parameter d is calculated as shown in formula (25) (where ):

[0112] (25)

[0113] In order to verify the advantages of the decoupling control strategy and the algorithm for constructing the β-axis current proposed in this application. This embodiment built two simulation models on the Simulink platform of Matlab for comparison. The specific input and output indicators of the simulation model are: the input AC voltage is 220V, 50HZ, and the output DC voltage is 400V. In the two sets of simulation models, all parameters of the topology used for the control of this embodiment are consistent, and the simulation step size is consistent. Then build a complete closed-loop control model for it. These two sets of closed-loop control models, one uses a delayed quarter-cycle algorithm to construct the β-axis current, and the other uses the algorithm proposed in this article to construct the β-axis current. The experimental results are as follows Fig.10 and Fig.11 shown. Fig.10 (a) is the d-axis reference current setting in this embodiment. , q-axis reference current The waveform diagram of the grid-side input voltage and grid-side input current obtained under the condition of . From this figure, it can be seen that the power factor angle can be controlled to zero through this application; Fig.10 (b) is the d-axis reference current setting in this embodiment. , q-axis reference current The waveform diagram of the grid-side input voltage and grid-side input current obtained under the condition of . It can also be seen that the power factor angle can be controlled to ; Fig.10 (c) is used to set the d-axis reference current in this embodiment. , q-axis reference current The waveform diagram of the grid-side input voltage and grid-side input current obtained under the condition of . It can also be seen that the power factor angle can be controlled to ; Fig.10 (d) is the d-axis reference current set in this embodiment. , q-axis reference current The waveform diagram of the grid-side input voltage and grid-side input current obtained under the condition of . It can also be seen that the power factor angle can be controlled to .exist Fig.11 This embodiment gives a comparison of the effects of the algorithm for constructing the β-axis current proposed in this application and the algorithm for delaying a quarter cycle. It can be seen that at the moment of power-on, the algorithm proposed in this application can quickly construct an accurate β-axis current, while the algorithm for delaying a quarter cycle needs about 40ms to construct an accurate orthogonal current. At 0.08s, this embodiment will The shaft current from Switch to In the case of a sudden change in the reference current, the algorithm proposed in the present application can still quickly and accurately construct the β-axis current, while the existing quarter-cycle delay algorithm also takes about 40ms to construct the accurate β-axis current.

[0114] The above is a detailed description of an embodiment of a single-stage bidirectional AC-DC converter control method provided by the present application. The following is a detailed description of an embodiment of a single-stage bidirectional AC-DC converter control device provided by the present application.

[0115] See also Fig.12 This embodiment provides a single-stage bidirectional AC-DC converter control device, which is applied to a single-stage bidirectional AC-DC converter. The single-stage bidirectional AC-DC converter includes: an LC filter circuit, a matrix conversion circuit, a high-frequency transformer, an LCL resonant circuit, an H-bridge circuit and an output filter circuit. The control device includes:

[0116] A circuit parameter relationship determination unit 201 is used to construct a circuit parameter relationship model of the equivalent circuit according to the input voltage and input current of the grid side of the single-stage bidirectional AC-DC converter and the equivalent circuit of the grid side of the single-stage bidirectional AC-DC converter, in combination with Kirchhoff's law, wherein the circuit parameter relationship model includes: a KVL equation and a KCL equation of the equivalent circuit;

[0117] A first relationship equation conversion unit 202, used to convert the circuit parameter relationship model into a dq coordinate system, and construct a filter capacitor voltage relationship equation in the dq coordinate system in combination with a preset switching cycle and an input current reference value;

[0118] A second relationship equation conversion unit 203 is used to determine the β-axis voltage relationship equation of the equivalent circuit according to the circuit parameter relationship model, and then perform Laplace transformation on the β-axis voltage relationship equation to obtain the orthogonal current relationship equation of the equivalent circuit;

[0119] The orthogonal current determination unit 204 is used to collect the actual input voltage and actual input current of the grid side of the single-stage bidirectional AC-DC converter, and obtain the β-axis orthogonal current by combining the filter capacitor voltage relationship equation and the orthogonal current relationship equation. The β-axis orthogonal current is used to determine the control parameters of the H-bridge circuit in combination with the preset current decoupling equation and the control parameter calculation equation.

[0120] See also Fig.13 , the embodiment of the present application provides a single-stage bidirectional AC-DC converter control terminal, including: a memory 33 and a processor 31, the memory 33 and the processor 31 can be connected via a communication bus 34;

[0121] The memory 33 is used to store program codes corresponding to a single-stage bidirectional AC-DC converter control method provided in the above embodiment of the present application;

[0122] The processor 31 is configured to read and execute the program code.

[0123] An embodiment of the present application provides a computer-readable storage medium, in which a program code corresponding to a single-stage bidirectional AC-DC converter control method provided in the above embodiment is stored. When the program code is executed by a processor, a single-stage bidirectional AC-DC converter control method provided in the above embodiment of the present application is implemented.

[0124] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the terminals, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0125] In the several embodiments provided in the present application, it should be understood that the disclosed terminals, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0126] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0127] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0128] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0129] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0130] If the integrated unit is implemented in the form of a software functional unit 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 the present invention, 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. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0131] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A single-stage bidirectional AC-DC converter control method, applied to a single-stage bidirectional AC-DC converter, the single-stage bidirectional AC-DC converter comprising: LC filter circuit, matrix conversion circuit, high frequency transformer, LCL resonant circuit, H bridge circuit and output filter circuit, characterized in that the control method includes: According to the input voltage and input current of the grid side of the single-stage bidirectional AC-DC converter and the equivalent circuit of the grid side of the single-stage bidirectional AC-DC converter, combined with Kirchhoff's law, a circuit parameter relationship model of the equivalent circuit is constructed, and the circuit parameter relationship model includes: a KVL equation and a KCL equation of the equivalent circuit; The circuit parameter relationship model is converted into a dq coordinate system, and a filter capacitor voltage relationship equation in the dq coordinate system is constructed in combination with a preset switching cycle and an input current reference value; Determining a β-axis voltage relationship equation of the equivalent circuit according to the circuit parameter relationship model, and then performing Laplace transformation on the β-axis voltage relationship equation to obtain an orthogonal current relationship equation of the equivalent circuit; The actual input voltage and actual input current of the grid side of the single-stage bidirectional AC-DC converter are collected, and the β-axis orthogonal current is obtained by combining the filter capacitor voltage relationship equation and the orthogonal current relationship equation. The β-axis orthogonal current is used to determine the control parameters of the H-bridge circuit in combination with the preset current decoupling equation and the control parameter calculation equation.

2. A single-stage bidirectional AC-DC converter control method according to claim 1, characterized in that: The filter capacitor voltage relationship equation is specifically: ； In the formula, , are the d-axis component and the q-axis component of the filter capacitor voltage in the equivalent circuit, , are the d-axis component and the q-axis component of the input voltage, is the equivalent inductance of the equivalent circuit, , are the d-axis component and q-axis component of the input current, , are the d-axis component and the q-axis component of the input current reference value, is the angular frequency of the input voltage, is the equivalent resistance of the equivalent circuit, is the switching cycle.

3. A single-stage bidirectional AC-DC converter control method according to claim 1, characterized in that: The orthogonal current relationship equation is specifically: ； In the formula, is the β-axis orthogonal current, is the β-axis component of the input voltage, is the β-axis component of the filter capacitor voltage, is the equivalent inductance of the equivalent circuit, is the Laplace operator.

4. A single-stage bidirectional AC-DC converter control method according to claim 1, characterized in that: The current decoupling equation is specifically: ； In the formula, , is the d-axis component and q-axis component of the decoupling current, is the equivalent capacitance of the equivalent circuit, , are the d-axis component and the q-axis component of the filter capacitor voltage in the equivalent circuit, , are the d-axis component and q-axis component of the input current, is the equivalent resistance of the equivalent circuit, is the angular frequency of the input voltage.

5. The single-stage bidirectional AC-DC converter control method according to claim 1, characterized in that: The current decoupling equation is specifically: ； In the formula, , is the d-axis component and q-axis component of the decoupling current, is the angular frequency of the input voltage, is the equivalent capacitance of the equivalent circuit, , are the d-axis component and the q-axis component of the filter capacitor voltage in the equivalent circuit, is the Laplace operator, is the equivalent inductance of the equivalent circuit, , are the d-axis component and the q-axis component of the input current.

6. A single-stage bidirectional AC-DC converter control method according to claim 1, characterized in that: The control parameters include: H-bridge output voltage duty cycle.

7. A single-stage bidirectional AC-DC converter control method according to claim 6, characterized in that: The control parameter calculation equation is specifically: ； ； Where, d is the H-bridge output voltage duty cycle, is the voltage value of the DC voltage source, is the switching angular frequency, m is the amplitude coefficient of the sine function, is the phase coefficient of the sine function, L is the inductance of the LCL resonant circuit, is the q-axis component of the reference value of the input current decoupled from the matrix conversion circuit in the dq coordinate system, is the d-axis component of the reference value of the input current of the matrix conversion circuit after decoupling in the dq coordinate system, n is the turns ratio of the high-frequency transformer, is the angular frequency of the input voltage.

8. A single-stage bidirectional AC-DC converter control device, applied to a single-stage bidirectional AC-DC converter, the single-stage bidirectional AC-DC converter comprising: LC filter circuit, matrix conversion circuit, high frequency transformer, LCL resonant circuit, H bridge circuit and output filter circuit, characterized in that the control device comprises: A circuit parameter relationship determination unit, configured to construct a circuit parameter relationship model of the equivalent circuit according to an input voltage and an input current on the grid side of a single-stage bidirectional AC-DC converter and an equivalent circuit on the grid side of the single-stage bidirectional AC-DC converter, in combination with Kirchhoff's law, wherein the circuit parameter relationship model includes: a KVL equation and a KCL equation of the equivalent circuit; A first relationship equation conversion unit, used to convert the circuit parameter relationship model into a dq coordinate system, and construct a filter capacitor voltage relationship equation in the dq coordinate system in combination with a preset switching cycle and an input current reference value; A second relationship equation conversion unit is used to determine the β-axis voltage relationship equation of the equivalent circuit according to the circuit parameter relationship model, and then perform Laplace transformation on the β-axis voltage relationship equation to obtain the orthogonal current relationship equation of the equivalent circuit; The orthogonal current determination unit is used to collect the actual input voltage and actual input current of the grid side of the single-stage bidirectional AC-DC converter, and obtain the β-axis orthogonal current by combining the filter capacitor voltage relationship equation and the orthogonal current relationship equation. The β-axis orthogonal current is used to determine the control parameters of the H-bridge circuit in combination with the preset current decoupling equation and the control parameter calculation equation.

9. A single-stage bidirectional AC-DC converter control terminal, characterized in that: include: Memory and processor; The memory is used to store a program code corresponding to a single-stage bidirectional AC-DC converter control method according to any one of claims 1 to 7; The processor is used for reading and executing the program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program code corresponding to a single-stage bidirectional AC-DC converter control method as described in any one of claims 1 to 7. When the program code is executed by a processor, a single-stage bidirectional AC-DC converter control method as described in any one of claims 1 to 7 is implemented.

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