Modulation method, converter modulation method, device, equipment and medium

Abstract

The invention provides a modulation method, a converter modulation method, a device, equipment and a medium, and relates to a power conversion technology. The modulation method comprises the following steps: for each switching period, acquiring key modulation input parameters of the MAB converter; the key modulation input parameters comprise N duty ratios, N-1 out-shift ratios, a global frequency reduction coefficient and an actual switching frequency; determining an output parameter according to the key modulation input parameter; the output parameters comprise N first half cycle duty ratios, N second half cycle duty ratios, N-1 first half cycle out-shift ratios, N-1 second half cycle out-shift ratios, first half cycle equivalent frequency reduction coefficients and second half cycle equivalent frequency reduction coefficients; and performing power modulation on input signals of N ports of the MAB converter according to the output parameters. According to the invention, the response speed can be guaranteed.

Description

Technical Field

[0001] This application relates to power conversion technology, and in particular, to a modulation method, a converter modulation method, a device, a device and a medium. Background Art

[0002] The multi-active bridge (MAB) converter is an isolated multi-port DC-DC converter, including N H-bridge converters and an N-winding high-frequency transformer. The basic working principle of the MAB converter is to adjust the transmitted power through the phase difference between the port AC voltages.

[0003] Currently, the modulation of the MAB converter usually adopts the traditional generalized phase shift (GPS) modulation method, including single phase shift modulation (SPS) and extended single phase shift modulation (ESSPS). The principle of GPS modulation is mainly based on controlling the on and off times of the switching tubes in each arm of the MAB converter, and realizing the power transmission and control by adjusting the phase difference between different arms.

[0004] When the MAB converter is modulated by GPS modulation, there is a defect of slow response. Summary of the Invention

[0005] Based on this, this application provides a modulation method, a converter modulation method, a device, a device and a medium to improve the response speed.

[0006] In a first aspect, this application provides a modulation method, which is applied to a multi-active bridge MAB converter, and the MAB converter includes N ports; the method includes:

[0007] For each switching period, obtain the key modulation input parameters of the MAB converter; the key modulation input parameters include N duty ratios, N-1 external phase shift ratios, a global frequency reduction coefficient, and an actual switching frequency;

[0008] According to the key modulation input parameters, determine the output parameters; the output parameters include N duty ratios in the first half cycle, N duty ratios in the second half cycle, N-1 external phase shift ratios in the first half cycle, N-1 external phase shift ratios in the second half cycle, an equivalent frequency reduction coefficient in the first half cycle, and an equivalent frequency reduction coefficient in the second half cycle;

[0009] Perform power modulation on the input signals of the N ports of the MAB converter according to the output parameters.

[0010] In a possible implementation manner, determining the output parameter according to the key modulation input parameter includes:

[0011] For the nth port, determine the duty cycle of the second half period of the nth port according to the duty cycle of the nth port, so that the duty cycle of the second half period of the nth port is consistent with the duty cycle of the nth port in the current switching cycle; where n ranges from 1 to N;

[0012] Determine the duty cycle of the first half period of the nth port according to the duty cycle of the second half period and the first assumption condition; the first assumption condition indicates that the time integral of the voltage in the first half period of the current switching cycle is equal to the average value of the time integral of the voltage in the second half period of the previous switching cycle and the time integral of the voltage in the second half period of the current switching cycle;

[0013] And / or, for the nth port, determine the equivalent frequency reduction coefficient of the first half period and the equivalent frequency reduction coefficient of the second half period of the nth port according to the global frequency reduction coefficient and the second assumption condition; the second assumption condition includes: the time integral of the voltage in the first half period of the current switching cycle is equal to the average value of the time integral of the voltage in the second half period of the previous switching cycle and the time integral of the voltage in the second half period of the current switching cycle, the change value of the DC voltage between the current switching cycle and the previous switching cycle is less than a preset value, and the positive time integral and the negative time integral of the independent excitation inductor current are the same within one switching cycle; where n ranges from 1 to N;

[0014] And / or, for the mth port, determine the external shift ratio of the first half period and the external shift ratio of the second half period of the mth port according to the external shift ratio and the second assumption condition; the second assumption condition includes: the time integral of the voltage in the first half period of the current switching cycle is equal to the average value of the time integral of the voltage in the second half period of the previous switching cycle and the time integral of the voltage in the second half period of the current switching cycle, the change value of the DC voltage between the current switching cycle and the previous switching cycle is less than a preset value, and the positive time integral and the negative time integral of the independent excitation inductor current are the same within one switching cycle; where m ranges from 2 to N.

[0015] In a possible implementation manner, the change value of the DC voltage between the current switching cycle and the previous switching cycle is less than a preset value.

[0016] In a possible implementation manner, for the nth port or the mth port, by adding a phase-shifted zero-voltage sequence and making the time for the independent excitation inductor current to maintain the positive peak value within one switching cycle equal to the time for maintaining the negative peak value, the assumption condition that the positive time integral and the negative time integral of the independent excitation inductor current are the same within one switching cycle is achieved.

[0017] In a possible implementation, obtaining the key modulation input parameters of the MAB converter includes:

[0018] Obtaining the current control parameters and state variables of the MAB converter; the control parameters include the power reference values and inductance parameters of each port, and the state variables include the DC voltages of each port;

[0019] According to the control parameters and the state variables, obtain the external shift ratios of N - 1 ports.

[0020] In a possible implementation, the obtaining the external shift ratios of N - 1 ports according to the control parameters and the state variables includes:

[0021] For each port, decompose the total power of the port according to a preset algorithm to obtain the relatively independent power control components of the port; the preset algorithm includes a power balance equation and circuit laws;

[0022] Based on the control parameters, the state variables, and the power control components, obtain the external shift ratio of the port through instantaneous power decoupling.

[0023] In a possible implementation, the duty cycle is related to the type of the modulation method.

[0024] In a possible implementation, the global frequency reduction coefficient is related to the application working conditions of the MAB converter. The greater the load indicated by the application working conditions, the smaller the global frequency reduction coefficient.

[0025] In a possible implementation, the actual switching frequency is related to the performance of the switching device applied in the MAB converter.

[0026] In a possible implementation, before determining the output parameters according to the key modulation input parameters, the method further includes:

[0027] Determine the total time length of the equivalent switching period of the switching period according to the actual switching frequency and the global frequency reduction coefficient of the switching period;

[0028] Determine the first half - period and the second half - period according to the total time length.

[0029] In a second aspect, the present application provides a converter modulation method, where the converter is a multi - active - bridge MAB converter; the method includes:

[0030] Obtain the current state information of the MAB converter; the state information includes the current modulation state and current parameters;

[0031] Control the MAB transformation to switch from the current modulation state to a target modulation state among preset modulation states according to the current parameters; the preset modulation states include modulation by the general phase-shift modulation GPS method and modulation by the modulation method according to any one of the first aspect.

[0032] In a possible implementation manner, the controlling the MAB transformation to switch from the current modulation state to a target modulation state among preset modulation states according to the current parameters includes:

[0033] When the current parameters meet a target preset condition, control the MAB converter to enter the target modulation state corresponding to the target preset condition; the current parameters include a system operation flag bit, a modulation mode flag bit, and input parameters.

[0034] In a possible implementation manner, the method further includes:

[0035] If the current modulation state is a stop modulation state, then when the target preset condition is that the system operation flag bit is a first value, the target modulation state corresponding to the target preset condition is modulation by the modulation method;

[0036] And / or, if the current modulation state is modulation by the power modulation method, then when the target preset condition is that the system operation flag bit is a second value, the target modulation state corresponding to the target preset condition is stop modulation; when the target preset condition is that the system operation flag bit is a first value, the modulation mode flag bit is a second value, and the duty cycle, the external phase shift ratio, and the actual switching frequency do not change in the previous two adjacent equivalent switching cycles, the target modulation state corresponding to the target preset condition is modulation by the modulation method;

[0037] And / or, if the current modulation state is modulation by the GPS modulation method, then when the target preset condition is that the system operation flag bit is a first value and the modulation mode flag bit is a first value, or, the system operation flag bit is a first value, the modulation mode flag bit is a second value, and the duty cycle, the external phase shift ratio, and the actual switching frequency change in the previous two adjacent equivalent switching cycles, or, the system operation flag bit is a second value, the target modulation state corresponding to the target preset condition is modulation by the GPS method.

[0038] In a possible implementation manner, the controlling the MAB transformation to switch from the current modulation state to a target modulation state among preset modulation states includes:

[0039] When the MAB converter reaches the conversion timing corresponding to the target modulation state, control the MAB converter to switch to the target modulation state.

[0040] In a possible implementation, the method further includes:

[0041] If the current modulation state is the stop modulation state and the target modulation state is modulation by the modulation method, the conversion timing is when the system operation flag bit is at the rising edge;

[0042] And / or, if the current modulation state is modulation by the modulation method and the target modulation state is the stop modulation state, the conversion timing is at the end of two equivalent switching cycles;

[0043] And / or, if the current modulation state is modulation by the modulation method and the target modulation state is modulation by the GPS modulation method, the conversion timing is when it is between π / 2 and π in the first half cycle or between 3π / 2 and 2π in the second half cycle of the first port of the MAB converter;

[0044] And / or, if the current modulation state is modulation by the GPS modulation method and the target modulation state is modulation by the modulation method, the conversion timing is when it is between π / 2 and π in the first half cycle or between 3π / 2 and 2π in the second half cycle of the first port of the MAB converter.

[0045] In a third aspect, the present application provides a modulation device applied to a multi-active-bridge MAB converter, where the MAB converter includes N ports; the device includes:

[0046] A first acquisition module, configured to acquire key modulation input parameters of the MAB converter for each switching cycle; the key modulation input parameters include N duty ratios, N - 1 external phase shift ratios, a global frequency reduction coefficient, and an actual switching frequency;

[0047] A determination module, configured to determine output parameters according to the key modulation input parameters; the output parameters include N duty ratios in the first half cycle, N duty ratios in the second half cycle, N - 1 external phase shift ratios in the first half cycle, N - 1 external phase shift ratios in the second half cycle, an equivalent frequency reduction coefficient in the first half cycle, and an equivalent frequency reduction coefficient in the second half cycle;

[0048] A modulation module, configured to perform power modulation on the MAB converter according to the output parameters.

[0049] In a fourth aspect, the present application provides a converter modulation device, where the converter is a multi-active-bridge MAB converter; the device includes:

[0050] A second acquisition module, configured to acquire the current status information of the MAB converter; the status information includes the current modulation status and the current parameters;

[0051] A switching module, configured to control the MAB conversion to switch from the current modulation status to a target modulation status in a preset modulation status according to the current parameters; the preset modulation status includes modulation by the Generalized Phase-Shift Modulation (GPS) method and modulation by the modulation method according to any one of the first aspect.

[0052] In a fifth aspect, the present application provides a multi-active-bridge converter. The multi-active-bridge (MAB) converter includes N ports and a controller, and the controller is configured to modulate the input signals of the N ports according to the method according to any one of the first aspect or the second aspect.

[0053] In a sixth aspect, the present application provides an electronic device, including a processor and a memory communicatively connected to the processor;

[0054] The memory stores computer-executable instructions;

[0055] The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of the first aspect or the second aspect.

[0056] In a seventh aspect, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored, and when the computer-executable instructions are executed by a processor, they are used to implement the method according to any one of the first aspect or the second aspect.

[0057] In an eighth aspect, the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the method according to any one of the first aspect or the second aspect.

[0058] The modulation method, converter modulation method, device, equipment and medium provided by this application are used to improve the modulation accuracy. Among them, the modulation method provided by this application can be executed by any electronic device. For each switching period, the electronic device first obtains the key modulation input parameters of the MAB converter, and then determines the output parameters including N duty ratios of the first half cycle, N duty ratios of the second half cycle, N - 1 external shift ratios of the first half cycle, N - 1 external shift ratios of the second half cycle, the equivalent frequency reduction coefficient of the first half cycle, and the equivalent frequency reduction coefficient of the second half cycle according to the key modulation input parameters. Finally, power modulation is performed on the input signals of the N ports of the MAB converter according to these output parameters. In this process, by separately setting parameters such as the duty ratios, external shift ratios, and equivalent frequency reduction coefficients of the first half cycle and the second half cycle, the output voltage and current in different time periods within each switching period can be more accurately controlled according to the actual situation, enabling the system to better adapt to load changes or control commands, thereby improving the response speed of the system to external changes. Description of the Drawings

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0060] Figure 1A Schematic diagram of an application scenario of a modulation method provided by an embodiment of the present application;

[0061] Figure 1B Topology diagram of an MAB converter provided by an embodiment of the present application;

[0062] Figure 1C Schematic diagram of a π - shaped equivalent circuit model of a multi - winding transformer considering the exciting inductance provided by an embodiment of the present application;

[0063] Figure 1D Schematic diagram of the high - frequency voltage of the H - bridge during GPS modulation of an MAB converter provided by an embodiment of the present application;

[0064] Figure 2 Schematic diagram of the flow of a modulation method provided by an embodiment of the present application I;

[0065] Figure 3A Schematic diagram of the flow of a modulation method provided by an embodiment of the present application Figure 2 ;

[0066] Figure 3B Schematic diagram of the relationship between the change in the exciting inductance current of port j and the duty ratio provided by an embodiment of the present application;

[0067] Figure 3C Schematic diagram of 10 time stages of an ALF-GPS modulation period provided by an embodiment of the present application;

[0068] Figure 3D Schematic diagram of the forward time integral and reverse time integral of the independent excitation inductance current of port j provided by an embodiment of the present application;

[0069] Figure 4 Comparison diagram of the effects of different modulation methods provided by an embodiment of the present application;

[0070] Figure 5 Schematic flow diagram of a converter modulation method provided by an embodiment of the present application;

[0071] Figure 6A Schematic diagram of the process of a converter modulation method provided by an embodiment of the present application;

[0072] Figure 6B Schematic diagram of the state transition timing between ALF-GPS modulation and GPS modulation provided by an embodiment of the present application;

[0073] Figure 7A - 7B Example diagram of implementation effect one provided by an embodiment of the present application;

[0074] Figure 8A - 8B Example of implementation effect provided by an embodiment of the present application Figure 2 ;

[0075] Figure 9A - 9B Example diagram of implementation effect three provided by an embodiment of the present application;

[0076] Figure 10A - 10B Example of implementation effect provided by an embodiment of the present application Figure 4 ;

[0077] Figure 11A - 11B Example of implementation effect provided by an embodiment of the present application Figure 5 ;

[0078] Figure 12A - 12B Example diagram of implementation effect six provided by an embodiment of the present application;

[0079] Figure 13 Schematic diagram of the structure of a modulation device provided by an embodiment of the present application;

[0080] Figure 14 Schematic diagram of the structure of a converter modulation device provided by an embodiment of the present application;

[0081] Figure 15A schematic structural diagram of an electronic device provided by an embodiment of the present application.

[0082] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and more detailed descriptions will be provided hereinafter. These drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Specific embodiments

[0083] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar components or components with the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present application.

[0084] It should be understood that the embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0085] The multi-active bridge (MAB) converter is an isolated multi-port DC-DC converter, including N H-bridge converters and an N-winding high-frequency transformer. The MAB converter adjusts the transferred power through the phase difference between the port AC voltages. When there is a phase difference between the AC voltages output by the H-bridge converters of different ports, a current will be generated in the transformer winding, thereby realizing power transmission. The magnitude of the phase difference determines the direction and magnitude of power transmission. For example, when the phase difference between the AC voltages of two ports is 0, the power transmission is 0; when the phase difference increases, the power transmission will also increase accordingly.

[0086] Currently, the modulation of the MAB converter usually adopts the traditional generalized phase shift (GPS) modulation method, including single phase shift modulation (SPS) and extended single phase shift modulation (ESSPS).

[0087] Among them, in SPS modulation, only a specific phase difference is adjusted, usually the phase difference between the H-bridge converters of two ports. By controlling the magnitude of this phase difference, the control of power transmission can be achieved. For example, in a two-port MAB converter, by only adjusting the phase difference between the output voltages of the two H-bridges, the power transmission between the two ports can be changed.

[0088] ESSPS is an extension based on SPS. In addition to adjusting the basic phase difference, other control parameters such as duty cycle are also introduced. By adjusting the phase difference and duty cycle simultaneously, the flexibility of power regulation can be improved to a certain extent.

[0089] As can be seen from the above, whether it is SPS or ESSPS, the control is mainly based on a few parameters such as phase difference and duty cycle. The MAB converter is a complex system, and its power transmission characteristics are affected by multiple factors such as port voltage, load characteristics, and transformer parameters. It is difficult to comprehensively and accurately control power transmission only by adjusting limited control parameters, which easily leads to a decrease in modulation accuracy.

[0090] In addition, in practical applications, the MAB converter may face various complex working conditions, such as rapid changes in load and fluctuations in port voltage. Due to limited control parameters, the GPS modulation method is difficult to quickly and accurately adapt to the changes of these complex working conditions, thus affecting the modulation accuracy.

[0091] Therefore, the embodiments of the present application provide a modulation method, a converter modulation method, a device, a device and a medium to solve the above problems. Specifically, in the modulation method of the present application, it is proposed that in each switching cycle, according to the key modulation input parameters of the MAB converter, output parameters including N duty ratios of the first half cycle, N duty ratios of the second half cycle, N-1 external shift ratios of the first half cycle, N-1 external shift ratios of the second half cycle, an equivalent frequency reduction coefficient of the first half cycle, and an equivalent frequency reduction coefficient of the second half cycle are determined, so as to perform power modulation on the input signals of N ports according to these output parameters.

[0092] In the method of the present application, by subdividing the above output parameters, compared with the modulation parameter control in the known technology, the modulation mode of the input signal can be adjusted more accurately according to the timing requirements of the MAB converter at different times, which is beneficial to enabling the system to adapt to load changes or control instructions faster and better, and effectively ensuring the response speed of the system to external changes.

[0093] It can be understood that the modulation method of the present application is applicable to the power modulation scenario of any MAB converter. For example, it is applicable to the power modulation scenario of a Dual Active Bridge (DAB) converter, or a Triple Active Bridge (TAB) converter, or a Quadruple Active Bridge (QAB) converter.

[0094] Exemplarily, Figure 1A is a schematic diagram of the application scenario of a modulation method provided by an embodiment of the present application. As Figure 1A shown, the modulation method of the present application can be used in the power modulation scenario of the MAB converter. Specifically, the method of the present application is executed by any electronic device. When performing power modulation on the MAB converter, the electronic device interacts with the MAB converter to obtain key modulation input parameters, determines output parameters based on the key modulation input parameters, and finally performs power modulation on the input signals of the N ports of the MAB converter according to the output parameters.

[0095] It can be understood that the electronic device can be set separately and communicate with the controller of the MAB converter in a wired or wireless manner, or can be integrated with the controller of the MAB converter as a part of the MAB converter. This is not limited in this embodiment.

[0096] When performing power modulation on the input signals of the N ports of the MAB converter through the above process, since the output parameters include the duty cycle of a half cycle, the external shift ratio, and the equivalent frequency reduction coefficient, the electronic device can achieve more accurate modulation of the input signals of the N ports, which is beneficial to ensuring the response speed.

[0097] For ease of understanding, the working principle of the MAB converter will be described in detail first in the present application. Specifically, Figure 1B is a topology diagram of an MAB converter provided by an embodiment of the present application. As Figure 1B shown, the MAB converter includes N H-bridge converters and an N-winding high-frequency transformer. For the N DC ports, their DC voltages and DC currents need to match the power supplies or loads connected to the ports respectively. The phases and duty cycles of the N AC square-wave voltages of the transformer are controlled by the N H-bridges, and the peak values of the square-wave voltages are clamped by the DC voltages of the H-bridges.

[0098] In the MAB converter, the function of the jth (j = 1,..., N) H-bridge is to convert the DC voltage V dc，j into a high-frequency square wave v with an adjustable duty cycle d j jThe high-frequency square-wave voltages output by N H-bridges are simultaneously applied to the N windings of the transformer, and the phase difference D between the individual high-frequency square-wave voltages j controls the alternating current i j , and further controls the power flow between the individual H-bridges, thereby achieving control of the power transfer of the MAB converter.

[0099] Specifically, when the MAB converter includes 5 DC ports, Figure 1C is a schematic diagram of the π-shaped equivalent circuit model of a multi-winding transformer considering the exciting inductance provided by an embodiment of the present application. As Figure 1C shown, L j，is is the inductance connected between terminals j and i, which is related to the power transferred between the ports and is called the power transfer inductance; L j，ms is the equivalent independent exciting inductance of the j-th winding. The sum of the currents of the N independent exciting inductances is equal to the actual exciting current The power transfer inductance L j，is and the independent exciting inductance L j，ms can be obtained by transforming the self-inductance mutual-inductance matrix L T . Among them, the self-inductance mutual-inductance matrix L T is a computable quantity and is expressed by formula (1)

[0100] In the linear inductance model, L j，is and L j，ms are fixed values. In practical applications, due to the existence of magnetic core saturation and hysteresis phenomena, L j，is and L j，ms may be non-constant values related to the instantaneous values of the main magnetic flux density B and magnetic field strength H of the transformer magnetic core and the magnetization state of the magnetic core.

[0101] It can be understood that for any inductor with saturation and hysteresis characteristics, when its terminal voltage is externally applied, the following formula (2) still applies according to the electromagnetic induction law: where Ψ is the magnetic flux linkage, n is the number of turns, B is the magnetic flux density, A is the cross-sectional area, e is the electromotive force, and v is the terminal voltage.

[0102] Furthermore, according to the self-inductance mutual-inductance matrix L T calculate the inverse matrix C Ts0 as an intermediate variable, expressed by formula (3): Furthermore, the inductance matrix L Ts0 in the π-shaped equivalent circuit model of the multi-winding transformer considering the exciting inductance can be obtained, expressed by formula (4): where the definitions of the elements in the inductance matrix are the same as those in the previous π-shaped equivalent circuit model.

[0103] On this basis, assuming that the DC voltage of H-bridge 1 is Vdc，1 , the DC voltage of H-bridge j is V dc，j , the DC voltage of H-bridge i is V dc，i . Figure 1D This is a schematic diagram of the high-frequency voltage of the H-bridge during GPS modulation provided by the embodiment of the present application. As Figure 1D shown, during GPS modulation, the high-frequency square wave output by H-bridge 1 is v1, and the high-frequency square wave output by H-bridge j is v j (frequency f act , duty cycle of half-switching period d j ∈[0, 1], external phase shift ratio D j ∈[-1 / 2, 1 / 2]), the high-frequency square wave output by H-bridge i is v i (frequency f act , duty cycle of half-switching period d i ∈[0, 1], external phase shift ratio D i ∈[-1 / 2, 1 / 2]). At this time, the difference in the external phase shift ratio between H-bridge j and H-bridge i is D j，i = D j - D i , and |D j，i | ≤ 1 / 2. Therefore, the (2N - 1) degrees of freedom during GPS modulation are d1, d2,..., d N ; assuming that the external phase shift ratio of the H-bridge with the most advanced phase is D1 = 0, the range of the external phase shift ratio is limited to D2 ∈ [0, 0.5],..., D N ∈[0, 0.5].

[0104] It should be understood that Table 1 is the average transfer power table of the MAB converter during GPS modulation. Specifically, it is used to illustrate the average power (average value of the switching period) transferred from H-bridge j to H-bridge i. Through this Table 1, when the phase shift conditions between H-bridge j and H-bridge i are known, the corresponding per-unit power value can be obtained, and then the corresponding average transfer power can be obtained. More specifically, the average transfer power transferred from H-bridge j to H-bridge i is the product of the corresponding per-unit power value and the reference power, where the average transfer power transferred from H-bridge j to H-bridge i is related to L j，is , f act , V dc，j , V dc，i , d j , d i , D j , D i related, and the reference power is expressed as P b，j，i .

[0105] Table 1 is the average transfer power table of the MAB converter during GPS modulation

[0106]

[0107] Based on the understanding of the working principle of the MAB converter, next, a modulation method and a converter modulation method provided by this application will be described in detail. It should be understood that the modulation method of this application is applied to the MAB converter, and the converter mentioned in the converter modulation method of this application is specifically the MAB converter, and the MAB converter includes N ports. It should be noted that a modulation method provided by this application is specifically the Asymmetric Lower Frequency - Generic Phase Shift (ALF - GPS) modulation method.

[0108] As an illustration, Figure 2 FIG. 1 is a schematic flow chart of a modulation method provided by an embodiment of this application. As Figure 2 shown, a modulation method provided by this application includes:

[0109] S201, for each switching period, obtain the key modulation input parameters of the MAB converter.

[0110] Among them, the key modulation input parameters include N duty cycles, N - 1 external phase shift ratios, a global frequency reduction coefficient, and an actual switching frequency.

[0111] It should be understood that the duty cycle is denoted as d j , d j ∈[0, 1], the external phase shift ratio is denoted as D j , D j ∈[0, 0.5], the global frequency reduction coefficient is denoted as R, R ≥ 1, and the actual switching frequency is denoted as f act , which is generally a fixed value.

[0112] In this embodiment, the electronic device obtains the external phase shift ratios of N - 1 ports of the MAB converter in the following manner: obtain the current control parameters and state variables of the MAB converter; according to the control parameters and state variables, obtain the external phase shift ratios of N - 1 ports. Among them, the control parameters include the power reference values and inductance parameters of each port, and the state variables include the DC voltages of each port.

[0113] More specifically, for each port, the electronic device decomposes the total power of the port according to a preset algorithm to obtain relatively independent power control components of the port; based on the control parameters, state variables, and power control components, the external phase shift ratio of the port is obtained through instantaneous power decoupling. Among them, the preset algorithm includes a power balance equation and circuit laws.

[0114] It can be understood that during actual closed-loop control operation, the key modulation input parameters are generally generated by the control loop. Therefore, in this embodiment, the target modulation parameters output by the upper-layer control according to the modulation target are specifically used as the key modulation input parameters for determining the output parameters.

[0115] In the modulation method of this embodiment, between port j and port i, the average transfer power in the first half cycle and the second half cycle (P FH，j，i , P SH，j，i ) can be derived respectively according to the following process and in combination with the GPS power characteristics given in Table 1:

[0116]

[0117] After obtaining the average transfer power in the first half cycle and the second half cycle, the total power P ALF-GPS，j , of port j can be further obtained, that is, the relatively independent power control component of port j. It can be understood that the total power P ALF-GPS，j of port j is the actual power value obtained by summing the average transfer power P FH，j，i , P SH，j，i between port j and other ports (x≠j) in the first half cycle and the second half cycle.

[0118] In this embodiment, the electronic device obtains the power reference values P 1，ref , P 2，ref , ……, P N，ref input by the upper-layer control of the MAB converter for each port, where P 1，ref + P 2，ref + …… + P N，ref = 0. It can be understood that the power reference values are the target power values set in the upper-layer control, and the sum of these power reference values is zero, reflecting the power balance requirements of the MAB converter.

[0119] The electronic device also needs to obtain the control parameters and state variables input by the upper-layer control of the MAB converter. On this basis, for any port j, through methods such as instantaneous power decoupling, the control parameters and state variables are analyzed and controlled so that the actual total power P ALF-GPS，j of port j is as close as possible to its corresponding power reference value P j，ref . For example, if P j，ref is a certain specific value and the calculated total power of the port is P ALF-GPS，j , the electronic device makes the total power P ALF-GPS，j match P j，ref to obtain the external shift ratio of port j.

[0120] It can be understood that different ALF-GPS modulation strategies have different duty cycles. Exemplarily, in ALF-SPS modulation, d j，k = 1; in ALF-ESSPS modulation, d j，k = a k Vdc, min, k / V dc，j，k , where a k ∈[0, 1] is the global duty cycle coefficient. Therefore, the duty cycle is related to the type of modulation method. In this embodiment, the electronic device obtains the duty cycle from a preset database according to the modulation method. Among them, the preset database stores multiple modulation strategies and their corresponding duty cycles.

[0121] It can be understood that the global frequency reduction coefficient is related to the application working condition of the MAB converter. The greater the load indicated by the application working condition, the smaller the global frequency reduction coefficient. In this embodiment, the electronic device obtains the application working condition of the MAB converter and searches for the corresponding global frequency reduction coefficient according to this application working condition. Exemplarily, when the actual operating voltage is small and a lower switching frequency is required to increase the average transfer power, assume that the switching frequencies of adjacent equivalent switching cycles are in the following relationship: That is, T act，k = b k T act，k-1 , so formula (5) can be obtained: b k = f act，k-1 / f act，k .

[0122] It can be understood that the actual switching frequency is related to the performance of the switching device applied by the MAB converter. In this embodiment, the electronic device specifically searches for and obtains the corresponding actual switching frequency according to the model of the switching device.

[0123] Optionally, in actual applications, the above N duty cycles, N - 1 outer shift ratios, global frequency reduction coefficient, and actual switching frequency may also be all or partially input by the user, and this embodiment does not limit this.

[0124] S202. Determine the output parameters according to the key modulation input parameters.

[0125] Specifically, the output parameters include N duty cycles of the first half cycle, N duty cycles of the second half cycle, N - 1 outer shift ratios of the first half cycle, N - 1 outer shift ratios of the second half cycle, equivalent frequency reduction coefficient of the first half cycle, and equivalent frequency reduction coefficient of the second half cycle.

[0126] In this embodiment, the electronic device first determines the total time length of the equivalent switching cycle of the switching cycle according to the actual switching frequency and the global frequency reduction coefficient of the switching cycle; determines the first half cycle and the second half cycle according to the total time length.

[0127] Assume that the global frequency reduction coefficient is R k , and use the equivalent frequency reduction coefficient R in the first half cycle FH，k and the equivalent frequency reduction coefficient R in the second half cycle SH，k to calculate the average value as the equivalent switching period frequency reduction coefficient R k . In addition, it can be understood that the equivalent switching frequency . On this basis, after the electronic device obtains the actual switching frequency and the global frequency reduction coefficient, it can obtain the total time length T of the equivalent switching period eq，k , . Further, evenly divide the total time length of the equivalent switching period to obtain the first half cycle and the second half cycle

[0128] . It can be understood that in this embodiment, different DC ports correspond to different half-cycle shift ratios and half-cycle duty ratios, but the same half-cycle equivalent frequency reduction coefficient is used for different DC ports

[0129] S203, perform power modulation on the input signals of the N ports of the MAB converter according to the output parameters

[0130] . Specifically, the electronic device generates corresponding drive signals for the switching tubes in the H-bridges of the N ports according to the N first-half-cycle duty ratios and second-half-cycle duty ratios to ensure that the switching tubes conduct and turn off in a predetermined time sequence. For example, for the four switching tubes of an H-bridge, determine the conduction time and turn-off time of each switching tube within an equivalent switching period according to the corresponding first-half-cycle duty ratio and second-half-cycle duty ratio

[0131] . The electronic device adjusts the phase relationship of the drive signals of the switching tubes between the N - 1 ports except the first port according to the N - 1 first-half-cycle shift ratios and second-half-cycle shift ratios. By precisely controlling the phase difference, flexible power distribution between different ports can be achieved. For example, by adjusting the shift ratio, the AC voltage phase of port A can be made to lead the AC voltage phase of port B, so that power is transferred from port A to port B

[0132] . The electronic device adjusts the drive signals of the switching tubes according to the first-half-cycle equivalent frequency reduction coefficient and the second-half-cycle equivalent frequency reduction coefficient to achieve the required switching frequency

[0133] . In the method provided in this embodiment, in each switching cycle, the electronic device obtains the output parameters of the equivalent switching period corresponding to the switching cycle through the obtained key modulation input parameters, and modulates the input signals of the MAB converter according to the output parameters

[0134] Through the method of this embodiment, the electronic device can accurately set and adjust the output parameters, and can adjust the key modulation input parameters in real time according to different working conditions and load changes, so as to adjust the output parameters in real time, enabling the MAB converter to quickly adapt to various working conditions, thereby effectively ensuring the response speed. For example, when the load power demand increases, the corresponding N-1 outer shift ratios and the like will change, so that the output parameters change to adapt to the current power transmission demand. In addition, it can be understood that reasonable power modulation can optimize the performance of the MAB converter, reduce switching losses, and improve efficiency.

[0135] As a further illustration, Figure 3A is a schematic flow chart of a modulation method provided by an embodiment of the present application Figure 2 , which is used to elaborate in detail the process of determining the output parameters. As Figure 3A shown, the method provided by the embodiment of the present application includes:

[0136] S301. For the nth port, determine the duty ratio of the second half cycle of the nth port according to the duty ratio of the nth port, so that the duty ratio of the second half cycle of the nth port is consistent with the duty ratio of the nth port in the current switching cycle.

[0137] Among them, the value of n is 1-N.

[0138] S302. Determine the duty ratio of the first half cycle of the nth port according to the duty ratio of the second half cycle and the first assumption condition.

[0139] Among them, the first assumption condition indicates that the time integral of the voltage in the first half cycle of the current switching cycle is equal to the average value of the time integral of the voltage in the second half cycle of the previous switching cycle and the time integral of the voltage in the second half cycle of the current switching cycle.

[0140] In this embodiment, the duty ratio of the nth port indicated by the key modulation input parameter is used as the duty ratio of the second half cycle of the nth port, that is, there is formula (6): d j，SH，k =d j，k , where n = j, d j，SH，k is used to represent the duty ratio of the second half cycle of the nth port, and d j，k is used to represent the duty ratio of the nth port. Specifically, the value of d j，k refers to the foregoing content and corresponds to the specific ALF-GPS modulation strategy.

[0141] When n = j, for the jth port, the voltage across the independent excitation inductor L j，ms is v jIn this embodiment, it is assumed that the time integral of the voltage in the first half cycle of the k-th switching period is equal to the average value of the voltage in the second half cycle of the (k - 1)-th switching period and the voltage in the second half cycle of the k-th switching period. Based on this assumption, that is, the first assumption condition, the electronic device determines the duty ratio of the first half cycle of the j-th port. On this basis, it can be understood that the first assumption condition is expressed as the following formula (7):

[0142] where d j，FH，k is used to represent the duty ratio of the first half cycle of the j-th port in the k-th switching period, and V dc，j，k is used to represent the voltage of the j-th port in the k-th switching period, and d j，SH，k-1 is used to represent the duty ratio of the second half cycle of the j-th port in the (k - 1)-th switching period, and V dc，j，k-1 is used to represent the voltage of the j-th port in the (k - 1)-th switching period, and d j，SH，k is used to represent the duty ratio of the second half cycle of the j-th port in the k-th switching period.

[0143] In this embodiment, the electronic device determines the duty ratio of the first half cycle by invoking the first assumption condition and combining it with the duty ratio of the second half cycle.

[0144] As a preferred example, the change value of the DC voltage between the current switching period and the previous switching period is less than a preset value. Specifically, in this embodiment, the preset value is an extremely small value, so as to approximately consider that the DC voltage is approximately constant within a switching period and is also approximately constant in adjacent switching periods, that is, V dc，j，k ≈V dc，j，k-1 . On this basis, combining the first assumption condition, it can be known that the duty ratio of the first half cycle of the j-th port can be expressed as the following formula (8):

[0145] Figure 3B is a schematic diagram of the relationship between the change of the independent excitation inductance current and the duty ratio of port j provided by the embodiment of the present application. It can be understood that, as Figure 3B shown, by determining the duty ratio of the first half cycle through the above first assumption condition, it can be ensured that the rising value of the independent excitation inductance current in the first half cycle of the k-th switching period is equal to the difference between the expected positive peak value of the independent excitation inductance current in the k-th switching period and the expected negative peak value of the independent excitation inductance current in the (k - 1)-th switching period, that is, the positive peak value and the negative peak value of the independent excitation inductance current are the same within a complete switching period: I j，ms，FH，k =I j，ms，SH，k , where I j，ms，FH，k is used to represent the independent excitation inductance current in the first half cycle of the k-th switching period, and I j，ms，SH，k is used to represent the independent excitation inductance current in the second half cycle of the k-th switching period.

[0146] That is to say, the duty ratio of the first half cycle obtained through the above first assumption condition can make the independent excitation inductance current of the corresponding port have no DC component and there is no bias in the magnetic core magnetic flux density in any transient state, thus not causing a large time constant and a long transient time, effectively avoiding transformer magnetic bias and the increase of AC and DC currents, and further effectively avoiding the reduction of the transient performance and the increase of losses of the MAB converter.

[0147] S303. For the nth port, determine the equivalent frequency reduction coefficient of the first half cycle and the equivalent frequency reduction coefficient of the second half cycle of the nth port according to the global frequency reduction coefficient and the second assumption condition.

[0148] Specifically, the second assumption condition includes: the time integral of the voltage in the first half cycle of the current switching period is equal to the average value of the time integral of the voltage in the second half cycle of the previous switching period and the time integral of the voltage in the second half cycle of the current switching period, the change value of the DC voltage between the current switching period and the previous switching period is less than a preset value, and the forward time integral and the reverse time integral of the independent excitation inductance current are the same within one switching period; where, n takes values from 1 to N.

[0149] S304. For the mth port, determine the external shift ratio of the first half cycle and the external shift ratio of the second half cycle of the mth port according to the external shift ratio and the second assumption condition.

[0150] Specifically, the second assumption condition includes: the time integral of the voltage in the first half cycle of the current switching period is equal to the average value of the time integral of the voltage in the second half cycle of the previous switching period and the time integral of the voltage in the second half cycle of the current switching period, the change value of the DC voltage between the current switching period and the previous switching period is less than a preset value, and the forward time integral and the reverse time integral of the independent excitation inductance current are the same within one switching period; where, m takes values from 2 to N.

[0151] Among them, as a preferred example, for the nth / mth port, by adding a phase-shifted zero-voltage sequence and making the time for the independent excitation inductance current to maintain the forward peak value within one switching period equal to the time for maintaining the reverse peak value, the assumption condition that the forward time integral and the reverse time integral of the independent excitation inductance current are the same within one switching period is realized.

[0152] In this embodiment, at the end of the first half cycle and the second half cycle, a phase-shifted zero-voltage sequence is added to each port. Specifically, the proportion of the zero-voltage duration added in the first half cycle and the second half cycle is (R FH，k -1) and (R SH，k -1) respectively, and the global frequency reduction coefficient R k of one complete cycle = 1 / 2(R FH，k +R SH，k ).

[0153] Table 2 Time Ratio Allocation Table for ALF-GPS Modulation

[0154]

[0155] More specifically, Table 2 is a time ratio allocation table for ALF-GPS modulation provided in this embodiment, Figure 3C which is a schematic diagram of 10 time stages of an ALF-GPS modulation period provided in an embodiment of this application. As shown in Table 2 and Figure 3C as shown, when phases ① and ⑥ are the first half cycle and the second half cycle respectively, the phase shift of port j relative to port 1. During this time period, the output voltage of the H-bridge is 0; phases ②, ④ and ⑦, ⑨ are the symmetric zero-voltage parts of the duty cycle of the square wave output of port j during the first half cycle and the second half cycle respectively. During this time period, the output voltage of the H-bridge is 0; phases ③ and ⑧ are the effective voltage parts of the duty cycle of the square wave output of port j during the first half cycle and the second half cycle respectively. During this time period, the output voltages of the H-bridge are V dc，j，k and -V dc，j，k respectively, and phases ⑤ and ⑩ are the parts after subtracting the phase shift time from the zero-voltage time added respectively after the first half cycle and the second half cycle. During this time period, the output voltage of the H-bridge is 0.

[0156] On this basis, Figure 3D which is a schematic diagram of the forward time integral and the reverse time integral of the independent excitation inductance current of port j provided in an embodiment of this application. As Figure 3D shown, in this embodiment, when n = j, on the basis that the forward and reverse peaks of the independent excitation inductance current are the same within one complete switching cycle (I' j，ms，FH，k = I' j，ms，SH，k ), assuming that the DC voltage of adjacent switching cycles is approximately constant, and further assuming that the time (T k，Area+ = t ④，k + t ⑤，k + t ⑥，k + t ⑦，k ) for the independent excitation inductance current to maintain the forward peak within one complete switching cycle is equal to the time (Tk, Area- = t ⑨，k + t ⑩，k + t ①，k+1 + t ②，k+1 ) to maintain the reverse peak, that is, the electronic device determines the equivalent frequency reduction coefficient of the first half cycle and the equivalent frequency reduction coefficient of the second half cycle of the nth port through the second assumption condition.

[0157] Furthermore, according to the above content, it can be known that the zero-voltage ratio addition needs to satisfy the following formula (9): t ④，k + t ⑤，k + t ⑥，k + t ⑦，k= t ⑨，k + t ⑩，k + t ①，k + 1 + t ②，k+1 , combined with Table 2 to obtain formula (10): and R FH，k - R SH，k = 2C k must be the same for all ports in the k-th switching period (2C k is a constant).

[0158] Since for port 1, there is Therefore, the following formulas (11) and (12) hold for all ports:

[0159]

[0160] In addition, since the total equivalent switching period length ratio satisfies formula (13): R FH，k + R SH，k + 2R k . Therefore, according to the previous formulas (11) and (13), the following formula (14) for determining the equivalent frequency reduction coefficient R FH，k in the first half period of the k-th switching period, and the formula (15) for determining the equivalent frequency reduction coefficient R SH，k in the second half period of the k-th switching period are finally obtained:

[0161]

[0162] where d 1，FH，k+1 is used to represent the duty ratio of the first half period of the first port in the (k + 1)-th switching period, and d 1，FH，k is used to represent the duty ratio of the first half period of the first port in the k-th switching period. D j，FH，k+1 is used to represent the shift out of the first half period of the j-th port in the (k + 1)-th switching period compared with, and D j，SH，k is used to represent the shift out of the second half period of the j-th port in the k-th switching period.

[0163] It can be understood that from formulas (14) and (15), in this embodiment, the electronic device specifically determines the equivalent frequency reduction coefficient of the half period according to the global frequency reduction coefficient and the duty ratio of the half period, and makes the elements involved satisfy the second preset condition.

[0164] Furthermore, the following formula (16) can be obtained from the aforementioned formula (12):

[0165]

[0166] On this basis, further according to the given value D of the shift out ratio of the k-th switching periodj，k , the following formula (17) for calculating the first-half cycle outward shift ratio D of the j-th port in the k-th switching period and formula (18) for calculating the second-half cycle outward shift ratio D of the j-th port in the k-th switching period can be obtained: j，FH，k of the j-th port in the k-th switching period: j，FH，k :

[0167]

[0168] As can be seen from the above formula (17) and formula (18), in this embodiment, the electronic device specifically calculates the outward shift ratio of the j-th port compared to D j，k and D j，k-1 , and the half-cycle duty ratio to calculate the half-cycle outward shift ratio, and makes the involved elements satisfy the second assumption condition.

[0169] Based on the above, in this embodiment, when the electronic device receives the key modulation input parameters, it specifically determines the output parameters by calling the following formula (19):

[0170]

[0171] wherein, Specifically, the electronic device obtains the output parameters by inputting the key modulation input parameters into the above formula (19).

[0172] In the method provided in this embodiment, when the electronic device calculates the output parameters, by making each element satisfy the second assumption condition, it can ensure that the independent excitation inductor current has no DC component and there is no transient core magnetic flux density bias, so as to effectively guarantee the transient performance of the MAB converter and reduce losses. In addition, by adding a phase-shifted zero-voltage sequence to achieve the assumption that the positive-time integral and the negative-time integral of the independent excitation inductor current in the second assumption condition are the same within one switching period, it ensures that the AC voltage and current in adjacent switching periods do not overlap in time, thereby avoiding problems such as abnormal pulse voltages, uncontrollable power transfer, and asymmetry of the time integral of the square-wave voltage and significant transient bias of the winding current when the working state and modulation parameters change. Furthermore, it is also beneficial to guarantee the transient performance of the MAB converter and reduce losses.

[0173] It can be understood that in the above ALF-GPS modulation process, the calculation of R FH，k and R SH，k requires the f value and d1 value at the k + 1 moment, and it must be obtained by delaying the key operating parameter instructions f act and d act and d j by one switching period. Further, if the generation of other key operating parameter instructions D j and R is related to fact and d j is related, it is necessary to synchronize the delay D j and R for one switching period. This characteristic of ALF-GPS modulation determines that when the key operating parameter instruction f act 、d j 、D j 、R suddenly changes in steps, the MAB converter needs at most 2 equivalent switching periods to reach the next fixed modulation state.

[0174] On this basis, this embodiment provides a preferred example, delaying f act and d j by one switching period to obtain the following formula:

[0175]

[0176] When the electronic device obtains the key modulation input parameters of the MAB converter, by calling this formula and combining the key modulation input parameters, the output parameters are obtained.

[0177] It can be understood that when calculating the half-cycle duty ratio and comparing the half-cycle outward shift, it is necessary to limit d j，FH，k ∈[0, 1], d j，SH，k ∈[0, 1], D j，FH，k ∈[0, 0.5], D j，SH，k ∈[0, 0.5], otherwise the condition of no transient-state DC bias may no longer be satisfied.

[0178] It can be understood that in the above ALF-GPS modulation process, the global frequency reduction coefficient R has a specific feasible minimum value. For any outward shift ratio D j ∈[0, 0.5], it can be simply fixed that R≥1.5. If it is necessary to dynamically maintain the frequency reduction coefficient R at the minimum value to increase the average transfer power, it is necessary to ensure where D max is the maximum outward shift ratio.

[0179] As a verification, Figure 4 is a comparison diagram of the effects of a different modulation method provided by the embodiment of the present application. As Figure 4 shown, the abscissa in this comparison diagram is the outward shift ratio, and the ordinate is the average transfer power. Figure 4 respectively gives the average power curve when using the ALF-GPS modulation method and the global frequency reduction coefficient R is 1.5, the average power curve when using the ALF-GPS modulation method and the global frequency reduction coefficient R is the minimum global frequency reduction coefficient R min and the average power curve when using the SPS modulation strategy.

[0180] From Figure 4It can be seen that when the external shift ratio D j，i is 0.5, the maximum average transfer power of the ALF-GPS modulation method is comparable to that of the GPS modulation. However, when modulating with ALF-GPS, the power curve slope at D j，i = 0 is lower, that is, compared with SPS, a larger external shift ratio D j，i is required for ALF-SPS to reach the same average transfer power.

[0181] As an illustration, Figure 5 FIG. is a schematic flow chart of a converter modulation method provided by an embodiment of the present application. As Figure 5 shown, a converter modulation method provided by an embodiment of the present application includes:

[0182] S501, obtaining the current state information of the MAB converter.

[0183] Among them, the state information includes the current modulation state and the current parameters.

[0184] S502, according to the current parameters, controlling the MAB conversion to switch from the current modulation state to the target modulation state in the preset modulation states.

[0185] Among them, the preset modulation states include modulation by the general phase shift modulation GPS method and modulation by the modulation method in the foregoing embodiments.

[0186] Specifically, in this embodiment, when the current parameters meet the target preset conditions, the MAB converter is controlled to enter the target modulation state corresponding to the target preset conditions. Among them, the current parameters include the system operation flag bit, the modulation mode flag bit, and the input parameters.

[0187] In this embodiment, when the electronic device reaches the conversion timing corresponding to the target modulation state of the MAB converter, the MAB converter is controlled to switch to the target modulation state.

[0188] More specifically, the correspondence relationship between the current modulation state, the target preset conditions, and the target modulation state is explained as:

[0189] If the current modulation state is the stop modulation state, the target preset condition is that the system operation flag bit is the first value, and the target modulation state corresponding to the target preset condition is modulation by the modulation method.

[0190] If the current modulation state is modulation by a modulation method, then when the target preset condition is that the system operation flag bit is the second value, the target modulation state corresponding to the target preset condition is stop modulation; when the target preset condition is that the system operation flag bit is the first value, the modulation mode flag bit is the second value, and the duty cycle, external shift ratio, and actual switching frequency do not change in the previous two adjacent equivalent switching cycles, the target modulation state corresponding to the target preset condition is modulation by a modulation method.

[0191] If the current modulation state is modulation by a GPS modulation method, then when the target preset condition is that the system operation flag bit is the first value and the modulation mode flag bit is the first value, or the system operation flag bit is the first value, the modulation mode flag bit is the second value, and the duty cycle, external shift ratio, and actual switching frequency change in the previous two adjacent equivalent switching cycles, or the system operation flag bit is the second value, the target modulation state corresponding to the target preset condition is modulation by a GPS method.

[0192] More specifically, the correspondence between the current modulation state, the conversion timing, and the target modulation state is explained as follows:

[0193] If the current modulation state is the stop modulation state and the target modulation state is modulation by a modulation method, then the conversion timing is when the system operation flag bit is at the rising edge.

[0194] If the current modulation state is modulation by a modulation method and the target modulation state is the stop modulation state, then the conversion timing is at the end of two equivalent switching cycles.

[0195] If the current modulation state is modulation by a modulation method and the target modulation state is modulation by a GPS modulation method, then the conversion timing is between π / 2 and π in the first half cycle or between 3π / 2 and 2π in the second half cycle of the first port of the MAB converter.

[0196] If the current modulation state is modulation by a GPS modulation method and the target modulation state is modulation by a modulation method, then the conversion timing is between π / 2 and π in the first half cycle or between 3π / 2 and 2π in the second half cycle of the first port of the MAB converter.

[0197] As can be seen from the above, in this embodiment, the modulation state of the MAB converter is divided into three states: stop modulation, modulation by a GPS modulation method, and modulation by the aforementioned ALF-GPS modulation method. The three states can be mutually converted according to the current modulation state, the target modulation state, the conversion timing, and the target preset condition.

[0198] Specifically, Table 3 is a summary table of state conversion parameter conditions and conversion times provided in this embodiment. As shown in Table 3, in this embodiment, the MAB converter is divided into four state conversions: ①, ②, ③, and ④. Each state conversion corresponds to a unique current modulation state, target modulation state, conversion time, and target preset condition for mutual conversion.

[0199] Table 3 Summary Table of State Conversion Parameter Conditions and Conversion Times

[0200]

[0201] More specifically, in this embodiment, on the basis of the key modulation input parameters, two system-level parameters are introduced: the modulation mode flag bit EN op and the system operation flag bit EN ALF . Among them, when the modulation mode flag bit is the first value, it indicates that the modulation state is still maintained by the ALF-GPS modulation method at constant parameters, otherwise it is not. Similarly, when the system operation flag bit is the first value, it indicates that the MAB converter is in the stop modulation state, otherwise it is not.

[0202] On the basis of the foregoing content, Figure 6A is a schematic diagram of the process of a converter modulation method provided by an embodiment of the present application. As shown in Table 3 and Figure 6A shown, state conversion ① indicates that the current modulation state is the stop modulation state, and the target modulation state is the state of modulation by the ALF-GPS modulation method. Correspondingly, the target preset condition is that the system operation flag bit is the first value, and the conversion time is when the system operation flag bit is at the rising edge.

[0203] State conversion ② indicates that the current modulation state is the state of modulation by the ALF-GPS modulation method, and the target modulation state is the stop modulation state. Correspondingly, the target preset condition and conversion time can be specifically referred to the foregoing content or Table 3, and will not be elaborated here.

[0204] State conversion ③ indicates that the current modulation state is the state of modulation by the ALF-GPS modulation method, and the target modulation state is the state of modulation by the GPS modulation method. Correspondingly, the target preset condition and conversion time can be specifically referred to the foregoing content or Table 3, and will not be elaborated here.

[0205] State conversion ④ indicates that the current modulation state is the state of modulation by the GPS modulation method, and the target modulation state is the state of modulation by the ALF-GPS modulation method. Correspondingly, the target preset condition and conversion time can be specifically referred to the foregoing content or Table 3, and will not be elaborated here.

[0206] It should be noted that for state conversion ②, at the falling edge moment of the system operation flag bit, d needs to be set immediatelyj = 0, D j = 0.

[0207] It can be understood that when the modulation mode flag bit is the second value and d j , D j is continuously changing, it is necessary to uniformly perform the conversion between π / 2 and π or between 3π / 2 and 2π, that is, set to perform the state conversion uniformly in the first half cycle or the second half cycle at each conversion, so as to ensure that there is no transient DC bias when the system frequently switches between ALF-GPS modulation and GPS modulation.

[0208] As an example, Figure 6B is a schematic diagram of the state conversion timing between ALF-GPS modulation and GPS modulation provided by an embodiment of the present application. As Figure 6B shown, the global carrier signal CR rises with a time slope of 2f act and is cleared when reaching R FH，k (during the first half cycle of ALF-GPS modulation) or R SH，k (during the second half cycle of ALF-GPS modulation) or 1 (during GPS modulation).

[0209] Among them, the first half cycle identification signal FH is set to 1 in the first half cycle and 0 in the second half cycle. The carrier signals CR1 to CR N are the carriers of N H-bridges respectively; the carrier CR j lags behind CR1 by a phase of D j，FH，k π (during the first half cycle of ALF-GPS modulation) or D j，SH，k π (during the second half cycle of ALF-GPS modulation) or D j，k π (during GPS modulation).

[0210] The carrier CR j is compared with d j，FH，k (during the first half cycle of ALF-GPS modulation) or -d j，SH，k (during the second half cycle of ALF-GPS modulation) or d j，k-1 (during the first half cycle of GPS modulation) or -d j，k-1 (during the second half cycle of GPS modulation), and finally the gate drive signal is output.

[0211] The method provided in this embodiment can cover all operating conditions, all modulation methods, and all modulation parameters of the MAB converter, and can reach the next fixed steady-state operating state in at most two equivalent switching periods, with small delay and high control accuracy. During all conversion processes, there are no transient-state biases in winding current, excitation current, and core magnetic flux density. When operating in a steady state, it can be switched to GPS modulation (including SPS modulation with the highest average power transfer) at any time, improving the upper limit of the average power transfer of the MAB converter. This strategy can be actually implemented as a global modulation state conversion strategy for the entire working process of the MAB converter.

[0212] As a verification, taking the QAB converter as an example, the implementation effect of the method in this embodiment is described. Specifically, assume that the physical parameters of the QAB converter are as follows: the transformer turns ratio has been reduced to 1; V dc,1 = 240V, V dc,2 = 220V, V dc,3 = 200V, V dc,4 = 180V; the series leakage inductance L s of each winding = 2μH; the T-shaped excitation inductance L m of the transformer ≈ 94.145μH, and the Preisach hysteresis model is adopted (core parameters: coercive force H c = 20A / m, remanent magnetic flux density B r = 0.16T, saturation magnetic field intensity H sat = 400A / m, saturation magnetic flux density B sat = 0.49T, saturation relative magnetic permeability μ r,sat = 1).

[0213] As a case, based on the following assumptions, the process of the mutation EN ALF is verified: the actual switching frequency fact = 50kHz in the operating parameters, duty ratios d1 = 0.7125, d2 = 0.7773, d3 = 0.855, d4 = 0.95, external shift ratios D1 = 0, D2 = 0.1, D3 = 0.15, D4 = 0.2, and frequency reduction coefficient R = 1.6.

[0214] For the process of the mutation EN ALF , it is further assumed that at time t = 5μs, the step change of EN op changes from 0 to 1 and remains; at time t = 100μs, the step change of EN ALF changes from 1 to 0, and at time t = 200μs, the step change of EN ALF changes from 0 to 1.

[0215] Based on this, Figure 7A - 7B FIG. 1 is an example diagram of the implementation effect provided by the embodiment of the present application. Specifically, Figure 7A andFigure 7B The time-domain waveforms of the sudden change of EN during the entire working process of the QAB converter from startup to stop ALF and the magnetic core B-H loop. More specifically, as Figure 7A - Figure 7B shown, the QAB converter system starts at the rising edge of EN op , and after EN ALF is set to 1 and then to 0, the system also switches from the ALF-GPS modulation state to the GPS modulation. The AC current in the transformer winding has no transient bias, and the exciting current has no transient bias. The QAB converter can achieve state conversion and output within two switching cycles.

[0216] It should be understood that in the figure, Im is the exciting current of the transformer (the sum of all independent exciting currents), Iac is the AC current of each port, Vac is the AC voltage of each port. Different curves in the AC current curve correspond to the AC currents of different ports, and different curves in the AC voltage curve correspond to the AC voltages of different ports.

[0217] As another case, based on the following assumptions, the process of the sudden change of f act is verified: Assume that the duty ratios in the operating parameters are d1 = 0.7125, d2 = 0.7773, d3 = 0.855, d4 = 0.95, the external shift ratios are D1 = 0, D2 = 0.1, D3 = 0.15, D4 = 0.2, and the frequency reduction coefficient R = 1.6. Further assume that at time t = 5 μs, the step change of EN op changes from 0 to 1 and remains; EN ALF = 0; at time t = 135 μs, the actual switching frequency f act changes from 50 kHz to 40 kHz in a stepwise manner.

[0218] Based on this,[[]] Figure 8A - 8B is an example of the implementation effect provided by the embodiment of the present application Figure 2 , specifically,[[]] Figure 8A and Figure 8B are respectively the time-domain waveforms and the magnetic core B-H loop of the QAB converter when the actual switching frequency changes in a stepwise manner (EN ALF = 0). From Figure 8A and Figure 8B it can be seen that when the actual switching frequency changes in a stepwise manner, the QAB converter system automatically detects the parameter change, switches back to the ALF-GPS modulation, changes the actual switching frequency, and then automatically switches back to the GPS modulation within two equivalent switching cycles (2×40 μs). The AC current in the transformer winding has no transient bias, and the exciting current has no transient bias; the operating state of the transformer is to switch to another fixed working loop around zero within two switching cycles, and the magnetic core has no transient DC bias.

[0219] As another case, based on the following assumptions, the process of the sudden change of the global frequency reduction coefficient R of the QAB converter is verified: the actual switching frequency f in the operating parameters act = 50 kHz, duty cycles d1 = 0.7125, d2 = 0.7773, d3 = 0.855, d4 = 0.95, external shift ratios D1 = 0, D2 = 0.1, D3 = 0.15, D4 = 0.2.

[0220] Further, it is assumed that at time t = 5 μs, EN op has a step change from 0 to 1 and remains, EN ALF = 0; at time t = 125 μs, the step change of the frequency reduction coefficient R changes from 1.6 to 2.

[0221] Based on this, Figure 9A - 9B FIG. III is an example diagram of an implementation effect provided by an embodiment of the present application. Specifically, Figure 9A and Figure 9B are respectively the time-domain waveforms and the core B-H loop when the QAB converter has a step change in EN ALF and suddenly changes the global frequency reduction coefficient R during the ALF-GPS modulation process. From Figure 9A and Figure 9B it can be seen that when the global frequency reduction coefficient has a step change, the equivalent switching frequency of the ALF-GPS modulation changes. There is no transient bias in the AC current of the transformer winding and no transient bias in the exciting current; the operating state of the transformer is a fixed operating loop around zero, there is no transient DC bias in the core, and the QAB converter can achieve conversion and output within two equivalent switching cycles.

[0222] As yet another case, based on the following assumptions, the process of the sudden change of the duty cycle d j of the QAB converter is verified: the actual switching frequency f in the operating parameters act = 50 kHz, duty cycles d1 = 0.7125, d3 = 0.855, d4 = 0.95, external shift ratios D1 = 0, D2 = 0.1, D3 = 0.15, D4 = 0.2, frequency reduction coefficient R = 1.6.

[0223] Further, it is assumed that at time t = 5 μs, EN op has a step change from 0 to 1 and remains, EN ALF = 0; at time t = 125 μs, the step change of the duty cycle d2 changes from 0.7773 to 0.5.

[0224] Based on this, Figure 10A - 10B FIG. is an example of an implementation effect provided by an embodiment of the present application Figure 4 , specifically, Figure 10A and Figure 10Bare the time-domain waveforms and the core B-H loop of the QAB converter when the duty cycle changes in steps (EN ALF = 0). It can be seen from Figure 10A - 10B that when the duty cycle changes in steps, the QAB converter system automatically detects the parameter change, switches back to the ALF-GPS modulation, changes the duty cycle, and then automatically switches back to the GPS modulation after the end of the next two equivalent switching cycles. There is no transient bias in the AC current of the transformer winding and no transient bias in the magnetizing current; the operating state of the transformer is to switch to another fixed operating loop around zero in two switching cycles, and there is no transient DC bias in the core.

[0225] As the fourth case, based on the following assumptions, the D j process of the QAB converter's sudden outward shift is verified: the actual switching frequency f act in the operating parameters = 50 kHz, the duty cycles d1 = 0.7125, d2 = 0.7773, d3 = 0.855, d4 = 0.95, the outward shift ratios D1 = 0, D3 = 0.15, D4 = 0.2, and the frequency reduction factor R = 1.6.

[0226] Furthermore, assuming that at time t = 5 μs, EN op the step change changes from 0 to 1 and remains, EN ALF = 0, and at time t = 125 μs, the step change of the outward shift ratio D2 changes from 0.1 to 0.

[0227] Based on this, Figure 11A - 11B is an example of the implementation effect provided by the embodiment of the present application Figure 5 . Specifically, Figure 11A and Figure 11B are the time-domain waveforms and the core B-H loop of the QAB converter when the outward shift ratio changes in steps (EN ALF = 0). It can be seen from Figure 11A - 11B that when the outward shift ratio changes in steps, the QAB converter system automatically detects the parameter change, switches back to the ALF-GPS modulation, changes the outward shift ratio, and then automatically switches back to the GPS modulation after the end of the next two equivalent switching cycles. There is no transient bias in the AC current of the transformer winding and no transient bias in the magnetizing current; the operating state of the transformer is a fixed operating loop around zero, and there is no transient DC bias in the core.

[0228] From the above verification process, it can be seen that through the converter modulation method of the present application, when any working condition changes or parameters change, it can reach the next fixed steady-state operating state within at most two equivalent switching cycles, with small delay and high control accuracy. During all conversion processes, there can be no transient bias in the winding current, magnetizing current, and core magnetic flux density.

[0229] As a further verification, taking the QAB converter in the above verification example as an example, the effects of the converter modulation method, SPS modulation method, and ESSPS modulation method of the present application are compared to verify the outstanding effect of the converter modulation method of the present application.

[0230] Specifically, based on the assumptions of the QAB converter above, assume the following operating parameters of the QAB converter: the actual switching frequency f act = 50 kHz, duty cycles d1 = 0.7125, d2 = 0.7773, d3 = 0.855, d4 = 0.95, external shift ratios D1 = 0, D3 = 0.15, D4 = 0.2, and frequency reduction coefficient R = 1.6. Further assume that at time t = 5 μs, EN op step change changes from 0 to 1 and remains; at time t = 250 μs, EN op step change changes from 1 to 0. At time t = 125 μs, the external shift ratio D2 step change changes from 0.1 to 0. When using the ALF-GPS modulation method, the frequency reduction coefficient R = 1.6, and the modulation mode selection instruction EN ALF = 0.

[0231] On this basis, Figure 12A - 12B FIG. VI is an example diagram of the implementation effect provided by an embodiment of the present application. Specifically, Figure 12A is a time-domain waveform comparison diagram of the modulation and conversion strategies (EN ALF = 0) of this patent, ESSPS modulation, and SPS modulation when the QAB converter has a step change in the external shift ratio (start -> sudden change in D2 -> stop). Figure 12B is a comparison diagram of the B-H loop of the magnetic core of the modulation and conversion strategies (EN ALF = 0) of the present application, ESSPS modulation, and SPS modulation when the QAB converter has a step change in the external shift ratio (start -> sudden change in D2 -> stop).

[0232] It can be seen from Figure 12A and Figure 12B that when using the modulation and conversion strategies of the present application, there is no transient and steady-state bias in the AC current of the transformer winding, no transient and steady-state bias in the exciting current, the operating state of the transformer is a fixed operating loop around zero, and there is no transient and steady-state DC bias in the magnetic core. When using ESSPS modulation or SPS modulation, there are large transient and steady-state biases in both the winding AC current and the exciting current, and there is also a large transient and steady-state bias in the magnetic core magnetic flux density.

[0233] The above embodiments introduce a modulation method and a converter modulation method from the perspective of the method flow. The following embodiments introduce a modulation device and a converter modulation device from the perspective of virtual modules or virtual units. For details, see the following embodiments.

[0234] An embodiment of the present application provides a modulation device, which is applied to a multi-active bridge (MAB) converter. The MAB converter includes N ports. Specifically, Figure 13 is a schematic structural diagram of a modulation device provided by an embodiment of the present application. As Figure 13 shown, the device includes:

[0235] A first acquisition module 131, configured to obtain key modulation input parameters of the MAB converter for each switching period. The key modulation input parameters include N duty cycles, N-1 external phase shift ratios, a global frequency reduction coefficient, and an actual switching frequency;

[0236] A determination module 132, configured to determine output parameters according to the key modulation input parameters. The output parameters include N duty cycles in the first half period, N duty cycles in the second half period, N-1 external phase shift ratios in the first half period, N-1 external phase shift ratios in the second half period, an equivalent frequency reduction coefficient in the first half period, and an equivalent frequency reduction coefficient in the second half period;

[0237] A modulation module 133, configured to perform power modulation on the MAB converter according to the output parameters.

[0238] In a possible implementation manner, the determination module 132 is specifically configured to:

[0239] For the nth port, determine the duty cycle in the second half period of the nth port according to the duty cycle of the nth port, so that the duty cycle in the second half period of the nth port is consistent with the duty cycle of the nth port in the current switching period; where n ranges from 1 to N;

[0240] Determine the duty cycle in the first half period of the nth port according to the duty cycle in the second half period and a first assumption condition. The first assumption condition indicates that the time integral of the voltage in the first half period of the current switching period is equal to the average value of the time integral of the voltage in the second half period of the previous switching period and the time integral of the voltage in the second half period of the current switching period;

[0241] And / or, for the nth port, determine the equivalent frequency reduction coefficient in the first half period and the equivalent frequency reduction coefficient in the second half period of the nth port according to the global frequency reduction coefficient and a second assumption condition. The second assumption condition includes: the time integral of the voltage in the first half period of the current switching period is equal to the average value of the time integral of the voltage in the second half period of the previous switching period and the time integral of the voltage in the second half period of the current switching period, the change value of the DC voltage between the current switching period and the previous switching period is less than a preset value, and the positive time integral and the negative time integral of the independent excitation inductor current are the same within one switching period; where n ranges from 1 to N;

[0242] And / or, for the m-th port, determine the outer-shift ratio of the first half cycle and the outer-shift ratio of the second half cycle of the m-th port according to the outer-shift ratio and the second assumption condition; the second assumption condition includes: the time integral of the voltage in the first half cycle of the current switching period is equal to the average value of the time integral of the voltage in the second half cycle of the previous switching period and the time integral of the voltage in the second half cycle of the current switching period, the change value of the DC voltage between the current switching period and the previous switching period is less than a preset value, and the forward time integral and the reverse time integral of the independent excitation inductor current are the same within one switching period; where m takes values from 2 to N.

[0243] In a possible implementation, the change value of the DC voltage between the current switching period and the previous switching period is less than a preset value.

[0244] In a possible implementation, for the n-th port or the m-th port, by adding a phase-shifted zero-voltage sequence and making the time for the independent excitation inductor current to maintain the forward peak value within one switching period equal to the time for maintaining the reverse peak value, the assumption condition that the forward time integral and the reverse time integral of the independent excitation inductor current are the same within one switching period is achieved.

[0245] In a possible implementation, the first acquisition module 131 is specifically configured to:

[0246] Acquire the current control parameters and state variables of the MAB converter; the control parameters include the power reference values and inductor parameters of each port, and the state variables include the DC voltages of each port;

[0247] According to the control parameters and state variables, acquire the outer-shift ratios of N - 1 ports.

[0248] In a possible implementation, the first acquisition module 131 is specifically configured to:

[0249] For each port, decompose the total power of the port according to a preset algorithm to obtain relatively independent power control components of the port; the preset algorithm includes a power balance equation and circuit laws;

[0250] Based on the control parameters, state variables, and power control components, obtain the outer-shift ratio of the port through instantaneous power decoupling.

[0251] In a possible implementation, the duty cycle is related to the type of modulation method.

[0252] In a possible implementation, the global frequency reduction coefficient is related to the application working condition of the MAB converter. The greater the load indicated by the application working condition, the smaller the global frequency reduction coefficient.

[0253] In a possible implementation, the actual switching frequency is related to the performance of the switching device applied by the MAB converter.

[0254] In a possible implementation, the determining module 132 is further configured to:

[0255] Determine the total time length of the equivalent switching period of the switching period according to the actual switching frequency of the switching period and the global frequency reduction coefficient;

[0256] Determine the first half period and the second half period according to the total time length.

[0257] A modulation device provided by an embodiment of the present application is applicable to the above-mentioned modulation method embodiment, which will not be elaborated here.

[0258] An embodiment of the present application further provides a converter modulation device, and the converter is a multi-active bridge MAB converter; specifically, Figure 14 FIG. is a schematic structural diagram of a converter modulation device provided by an embodiment of the present application, as Figure 14 shown, the device includes:

[0259] A second acquisition module 141, configured to acquire the current state information of the MAB converter; the state information includes the current modulation state and the current parameters;

[0260] A switching module 142, configured to control the MAB conversion to switch from the current modulation state to the target modulation state in the preset modulation states according to the current parameters; the preset modulation states include modulation by the general phase-shifted modulation GPS method and modulation by any one of the modulation methods in the foregoing method embodiments.

[0261] In a possible implementation, the switching module 142 is specifically configured to:

[0262] When the current parameters meet the target preset conditions, control the MAB converter to enter the target modulation state corresponding to the target preset conditions; the current parameters include the system operation flag bit, the modulation mode flag bit, and the input parameters.

[0263] In a possible implementation, the switching module 142 is further configured to:

[0264] If the current modulation state is the stop modulation state, when the target preset condition is that the system operation flag bit is the first value, the target modulation state corresponding to the target preset condition is modulation by the modulation method;

[0265] And / or, if the current modulation state is modulation by a modulation method, when the target preset condition is that the system operation flag bit is the second value, the target modulation state corresponding to the target preset condition is stop modulation; when the target preset condition is that the system operation flag bit is the first value, the modulation mode flag bit is the second value, and the duty cycle, external shift ratio, and actual switching frequency do not change in the previous two adjacent equivalent switching cycles, the target modulation state corresponding to the target preset condition is modulation by a modulation method;

[0266] And / or, if the current modulation state is modulation by a GPS modulation method, when the target preset condition is that the system operation flag bit is the first value and the modulation mode flag bit is the first value, or, the system operation flag bit is the first value, the modulation mode flag bit is the second value, and the duty cycle, external shift ratio, and actual switching frequency change in the previous two adjacent equivalent switching cycles, or, the system operation flag bit is the second value, the target modulation state corresponding to the target preset condition is modulation by a GPS method.

[0267] In a possible implementation manner, the switching module 142 is specifically configured to:

[0268] When the MAB converter reaches the conversion timing corresponding to the target modulation state, control the MAB converter to switch to the target modulation state.

[0269] In a possible implementation manner, the switching module 142 is further configured to:

[0270] If the current modulation state is the stop modulation state and the target modulation state is modulation by a modulation method, the conversion timing is when the system operation flag bit is at the rising edge;

[0271] And / or, if the current modulation state is modulation by a modulation method and the target modulation state is the stop modulation state, the conversion timing is at the end of two equivalent switching cycles;

[0272] And / or, if the current modulation state is modulation by a modulation method and the target modulation state is modulation by a GPS modulation method, the conversion timing is between π / 2 and π in the first half cycle or between 3π / 2 and 2π in the second half cycle of the first port of the MAB converter;

[0273] And / or, if the current modulation state is modulation by a GPS modulation method and the target modulation state is modulation by a modulation method, the conversion timing is between π / 2 and π in the first half cycle or between 3π / 2 and 2π in the second half cycle of the first port of the MAB converter.

[0274] A converter modulation device provided by an embodiment of the present application is applicable to the above-mentioned converter modulation method embodiment, and will not be elaborated here.

[0275] An embodiment of the present application further provides a multi-active bridge converter, including N ports and a controller, and the controller is configured to modulate the input signals of the N ports according to the method indicated by any of the foregoing method embodiments.

[0276] An embodiment of the present application provides an electronic device. Figure 15 As shown in the schematic structural diagram of an electronic device provided by an embodiment of the present application, Figure 15 as shown, the electronic device includes: a processor 151 and a memory 152. Among them, the processor 151 and the memory 152 are connected, such as connected through a bus 153. Optionally, the electronic device may further include a transceiver 154. It should be noted that in practical applications, the transceiver 154 is not limited to one, and the structure of the electronic device does not constitute a limitation to the embodiments of the present application.

[0277] The processor 151 may be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute various exemplary logical blocks, modules, and circuits described in connection with the disclosure of the present application. The processor 151 may also be a combination that implements computing functions, such as a combination including one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0278] The bus 153 may include a path for transmitting information between the above components. The bus 153 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 153 may be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, Figure 15 only a thick line is used to represent it in the figure, but it does not mean that there is only one bus 153 or one type of bus 153.

[0279] The memory 152 can be a read only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or can also be an electrically erasable programmable read only memory (EEPROM), a compact disc read only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0280] The memory 152 is used to store the application program code for executing the solution of this application and is controlled by the processor 151 for execution. The processor 151 is used to execute the application program code stored in the memory 152 to implement the content shown in the foregoing method embodiments.

[0281] This application also provides a computer-readable storage medium, which may include: various media that can store program code such as USB flash drives, external hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks or optical discs, etc. Specifically, the computer-readable storage medium stores program instructions, and the program instructions are used to implement the methods in the foregoing embodiments.

[0282] This application embodiment also provides a computer program product, including a computer program, which implements the technical solutions of the foregoing method embodiments when executed by a processor. The implementation principle and technical effects are similar and will not be elaborated here.

[0283] Those skilled in the art will readily think of other implementation schemes of this application after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of this application, which follow the general principles of this application and include the common general knowledge or conventional technical means in the technical field not disclosed in this application. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of this application are pointed out by the claims.

[0284] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A modulation method, characterized in that: Applied to a multi-active bridge MAB converter, the MAB converter includes N ports; the method includes: For each switching cycle, key modulation input parameters of the MAB converter are obtained; the key modulation input parameters include N duty cycles, N-1 external shift ratios, a global frequency reduction coefficient, and an actual switching frequency; Determine output parameters according to the key modulation input parameters; the output parameters include N first half cycle duty cycles, N second half cycle duty cycles, N-1 first half cycle outward shift ratios, N-1 second half cycle outward shift ratios, first half cycle equivalent frequency reduction coefficients, and second half cycle equivalent frequency reduction coefficients; The input signals of the N ports of the MAB converter are power modulated according to the output parameters.

2. The method according to claim 1, characterized in that The step of determining the output parameter according to the key modulation input parameter comprises: For the nth port, determine the second half cycle duty cycle of the nth port according to the duty cycle of the nth port, so that the second half cycle duty cycle of the nth port is consistent with the duty cycle of the nth port in the current switching cycle; wherein the value of n is 1-N; Determine the first half cycle duty cycle of the nth port according to the second half cycle duty cycle and a first assumption condition; the first assumption condition indicates that the time integral of the first half cycle voltage of the current switching cycle is equal to the average value of the time integral of the second half cycle voltage of the previous switching cycle and the time integral of the second half cycle voltage of the current switching cycle; And / or, for the nth port, according to the global frequency reduction coefficient and the second assumption condition, determine the first half cycle equivalent frequency reduction coefficient and the second half cycle equivalent frequency reduction coefficient of the nth port; the second assumption condition includes: the time integral of the first half cycle voltage of the current switching cycle is equal to the average value of the time integral of the second half cycle voltage of the previous switching cycle and the time integral of the second half cycle voltage of the current switching cycle, the change value of the DC voltage between the current switching cycle and the previous switching cycle is less than a preset value, and the forward time integral and the reverse time integral of the independent excitation inductor current are the same within one switching cycle; And / or, for the mth port, the first half cycle outward shift comparison and the second half cycle outward shift comparison of the mth port are determined according to the outward shift comparison and the second assumption condition; the second assumption condition includes: the time integral of the first half cycle voltage of the current switching cycle is equal to the average value of the time integral of the second half cycle voltage of the previous switching cycle and the time integral of the second half cycle voltage of the current switching cycle, the change value of the DC voltage between the current switching cycle and the previous switching cycle is less than a preset value, and the forward time integral and reverse time integral of the independent excitation inductor current are the same within one switching cycle; wherein, the value of m is 2-N.

3. The method according to claim 2, characterized in that A change in the DC voltage between the current switching cycle and the previous switching cycle is less than a preset value.

4. The method according to claim 2 or 3, characterized in that: For the nth port or the mth port, by adding a phase-shifted zero voltage sequence and making the time for which the independent magnetizing inductor current in one switching cycle maintains the forward peak value equal to the time for which the independent magnetizing inductor current maintains the reverse peak value, the assumption that the forward time integral and the reverse time integral of the independent magnetizing inductor current are the same in one switching cycle is realized.

5. The method according to any one of claims 1 to 3, characterized in that: The obtaining of key modulation input parameters of the MAB converter comprises: Acquire the current control parameters and state variables of the MAB converter; the control parameters include the power reference value and inductance parameter of each port, and the state variables include the DC voltage of each port; According to the control parameter and the state variable, the outbound shift ratios of N-1 ports are obtained.

6. The method according to claim 5, characterized in that The step of obtaining the outward shift ratio of N-1 ports according to the control parameter and the state variable includes: For each port, decomposing the total power of the port according to a preset algorithm to obtain a relatively independent power control component of the port; the preset algorithm includes a power balance equation and a circuit law; Based on the control parameter and the state variable, as well as the power control component, the outward shift ratio of the port is obtained by instantaneous power decoupling.

7. The method according to any one of claims 1 to 3, characterized in that: The duty cycle is related to the type of the modulation method.

8. The method according to any one of claims 1 to 3, characterized in that: The global frequency reduction coefficient is related to the application condition of the MAB converter. The greater the load indicated by the application condition, the smaller the global frequency reduction coefficient.

9. The method according to any one of claims 1 to 3, characterized in that: The actual switching frequency is related to the performance of the switching device used in the MAB converter.

10. The method according to any one of claims 1 to 3, characterized in that: Before determining the output parameter according to the key modulation input parameter, the method further includes: Determining the total time length of an equivalent switching cycle of the switching cycle according to an actual switching frequency of the switching cycle and a global frequency reduction coefficient; The first half period and the second half period are determined according to the total time length.

11. A converter modulation method, characterized in that: The converter is a multi-active bridge MAB converter; the method comprises: Acquire the current state information of the MAB converter; the state information includes the current modulation state and current parameters; According to the current parameters, the MAB transformation is controlled to switch from the current modulation state to a target modulation state in a preset modulation state; the preset modulation state includes modulation by a general phase shift modulation GPS method and modulation by a modulation method as described in any one of claims 1-9.

12. The method according to claim 11, characterized in that The step of controlling the MAB transformation to switch from the current modulation state to a target modulation state in a preset modulation state according to the current parameter includes: When the current parameters meet the target preset conditions, the MAB converter is controlled to enter the target modulation state corresponding to the target preset conditions from the current modulation state; the current parameters include a system operation flag, a modulation mode flag, and input parameters.

13. The method according to claim 12, characterized in that The method further comprises: If the current modulation state is the stop modulation state, the target preset condition is that when the system operation flag is a first value, the target modulation state corresponding to the target preset condition is modulation by the modulation method; And / or, if the current modulation state is modulation by the modulation method, then when the target preset condition is that the system operation flag is the second value, the target modulation state corresponding to the target preset condition is stop modulation; when the target preset condition is that the system operation flag is the first value, the modulation mode flag is the second value, and the duty cycle, the external shift phase, and the actual switching frequency do not change in the first two adjacent equivalent switching cycles, the target modulation state corresponding to the target preset condition is modulation by the modulation method; And / or, if the current modulation state is modulated by the GPS modulation method, then the target preset condition is that the system operation flag is the first value and the modulation mode flag is the first value, or the system operation flag is the first value and the modulation mode flag is the second value, and the duty cycle, the external shift phase, and the actual switching frequency change within the first two adjacent equivalent switching cycles, or the system operation flag is the second value, the target modulation state corresponding to the target preset condition is modulation by the GPS method.

14. The method according to claim 12, characterized in that The controlling the MAB conversion to switch from the current modulation state to a target modulation state in a preset modulation state includes: When the MAB converter reaches a switching timing corresponding to the target modulation state, the MAB converter is controlled to switch to the target modulation state.

15. The method according to claim 14, characterized in that The method further comprises: If the current modulation state is the stop modulation state and the target modulation state is the modulation by the modulation method, the switching timing is when the system operation flag is at a rising edge; And / or, if the current modulation state is modulation by the modulation method and the target modulation state is a stop modulation state, then the switching timing is when two equivalent switching cycles end; and / or, if the current modulation state is modulation by the modulation method and the target modulation state is modulation by the GPS modulation method, the switching timing is between π / 2 and π in the first half cycle or between 3π / 2 and 2π in the second half cycle of the first port of the MAB converter; And / or, if the current modulation state is modulation by the GPS modulation method and the target modulation state is modulation by the modulation method, then the conversion timing is between the first half cycle π / 2 and π or the second half cycle 3π / 2 and 2π of the first port of the MAB converter.

16. A modulation device, characterized in that: Applicable to a multi-active bridge MAB converter, the MAB converter includes N ports; the device includes: A first acquisition module is used to acquire key modulation input parameters of the MAB converter for each switching cycle; the key modulation input parameters include N duty cycles, N-1 external shift ratios, a global frequency reduction coefficient, and an actual switching frequency; A determination module, used to determine output parameters according to the key modulation input parameters; the output parameters include N first half cycle duty cycles, N second half cycle duty cycles, N-1 first half cycle outward shift ratios, N-1 second half cycle outward shift ratios, first half cycle equivalent frequency reduction coefficients, and second half cycle equivalent frequency reduction coefficients; A modulation module is used to perform power modulation on the MAB converter according to the output parameter.

17. A converter modulation device, characterized in that: The converter is a multi-active bridge MAB converter; the device comprises: A second acquisition module is used to acquire the current state information of the MAB converter; the state information includes the current modulation state and the current parameters; A switching module is used to control the MAB transformation to switch from the current modulation state to a target modulation state in a preset modulation state according to the current parameters; the preset modulation state includes modulation by a general phase shift modulation GPS method and modulation by a modulation method as described in any one of claims 1 to 10.

18. A multi-active bridge converter, characterized in that: The multiple active bridge MAB converter comprises N ports and a controller, wherein the controller is used to modulate input signals of the N ports according to the method according to any one of claims 1 to 15.

19. An electronic device, characterized in that: comprising a processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 15.

20. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 15 when executed by a processor.

21. A computer program product, characterized in that The method comprises a computer program, which, when executed by a processor, implements the method according to any one of claims 1 to 15.

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