Control method of three-phase conversion circuit, control circuit, and electronic device

Abstract

The application discloses a control method of a three-phase conversion circuit, a control circuit and electronic equipment. The control method comprises the following steps: determining one phase in the three-phase conversion circuit corresponding to the input voltage with the maximum absolute value among the A, B and C three-phase input voltages as a triangular current control phase, and determining the other two phases as current discontinuous control phases; obtaining the first energy storage time, the first freewheeling time and the first switching period by using the first energy storage inductance voltage and the first freewheeling inductance voltage of the triangular current control phase, so as to generate a first control signal for controlling the triangular current control phase; and obtaining the second energy storage time and the second freewheeling time corresponding to each phase by using the first switching period and each second characteristic parameter, so as to generate a second control signal for controlling the current discontinuous control phases. In the foregoing manner, the control method of the three-phase conversion circuit can facilitate the realization of zero-voltage turn-on and / or valley bottom voltage turn-on, improve the efficiency and reduce the cost.

Description

Technical Field

[0001] This application relates to the field of circuit control technology, and in particular to a control method, control circuit and electronic equipment for a three-phase conversion circuit. Background Technology

[0002] In the field of power electronics, three-phase converters are widely used in new energy power generation, electric vehicle drives, and industrial frequency converters due to their advantages such as high power density and high-efficiency transmission. With increasing demands for dynamic response and compact size, higher frequency conversion has become a crucial development direction for three-phase converters. To overcome the bottleneck that sharp voltage / current changes generated by high-frequency hard switching exacerbate electromagnetic interference and thus affect system reliability, soft-switching technology has emerged.

[0003] However, the coordinated control of multiple switching devices in a three-phase converter presents unique challenges to the implementation of soft switching. Traditional soft switching technologies generally suffer from problems such as an excessively wide range of switching frequency variations and current distortion caused by sector switching. Summary of the Invention

[0004] The main technical problem addressed by this application is to provide a control method, control circuit, and electronic equipment for a three-phase converter circuit, which can solve the problems of excessively wide switching frequency variation range and current distortion caused by sector switching in the existing control methods for three-phase converter circuits.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: providing a control method for a three-phase converter circuit, wherein the control method includes: acquiring the A-phase input voltage, B-phase input voltage, and C-phase input voltage of the three-phase converter circuit; determining one phase of the three-phase converter circuit corresponding to the phase with the largest absolute value of amplitude among the A-phase input voltage, B-phase input voltage, and C-phase input voltage as the triangular current control phase; determining the other two phases of the three-phase converter circuit as current discontinuous control phases; acquiring a first characteristic parameter of the triangular current control phase and a second characteristic parameter of each current discontinuous control phase; wherein the first characteristic parameter includes a first energy storage inductor voltage and a first freewheeling current... Inductor voltage; using the first energy storage inductor voltage and the first freewheeling inductor voltage, obtain the first energy storage time and the first freewheeling time; using the first energy storage time and the first freewheeling time, obtain the first switching cycle; using the first energy storage time and the first freewheeling time, generate the first control signal; using the first switching cycle and each second characteristic parameter, obtain each corresponding second energy storage time and the second freewheeling time; using each corresponding second energy storage time and the second freewheeling time, generate the second control signal; send the first control signal and each second control signal to the triangular current control phase and each current discontinuous control phase, respectively, to trigger the triangular current control phase and each current discontinuous control phase to change their switching states.

[0006] The first characteristic parameters further include a first input voltage, a first output reference voltage, a second output reference voltage, a first filter capacitor voltage, a first input current, and a filter inductance value. Before the step of obtaining the first energy storage time and the first freewheeling time using the first energy storage inductance voltage and the first freewheeling inductance voltage, the method further includes: obtaining the first energy storage inductance voltage and the first freewheeling inductance voltage using the first input voltage, the first output reference voltage, the second output reference voltage, and the first filter capacitor voltage; the step of obtaining the first energy storage time and the first freewheeling time using the first energy storage inductance voltage and the first freewheeling inductance voltage includes: obtaining the first energy storage time and the first freewheeling time using the first energy storage inductance voltage, the first freewheeling inductance voltage, the first input current, and the filter inductance value.

[0007] The first characteristic parameter further includes input power, first input voltage, and effective value of input phase voltage. Before the step of obtaining the first energy storage time and first freewheeling time using the first energy storage inductor voltage, first freewheeling inductor voltage, first input current, and filter inductor value, the method further includes obtaining the first input current using the input power, first input voltage, and effective value of input phase voltage.

[0008] The first characteristic parameter also includes setting a negative current. The steps of obtaining the first energy storage time and the first freewheeling time using the first energy storage inductor voltage, the first freewheeling inductor voltage, the first input current, and the filter inductor value include: using a first adjustment function to calculate and process the first energy storage time and the first freewheeling time using the first energy storage inductor voltage, the first freewheeling inductor voltage, the first input current, the filter inductor value, and the set negative current. The calculation formula for the first adjustment function is as follows: ; ; Among them, T on_TCM For the first energy storage time, T off_TCM For the first continuous flow time, I avg_T For the first input current, I R To set the negative current, L is the value of the filter inductance, and U... Lon_T U is the voltage of the first energy storage inductor. Loff_T This is the voltage of the first freewheeling inductor.

[0009] The first control signal includes a first drive signal and a second drive signal. The step of generating the first control signal using the first energy storage time and the first freewheeling time includes: adjusting the first drive signal to a first level state at the beginning of the first switching cycle; adjusting the first drive signal from the first level state to a second level state after the first energy storage time; adjusting the second drive signal from the second level state to the first level state after a first dead time delay; adjusting the second drive signal from the first level state to the second level state after the first freewheeling time; or, in response to the first inductor current in the triangular current control phase crossing zero, adjusting the second drive signal from the first level state to the second level state after a first set time delay.

[0010] The second characteristic parameters include the second input current, the filter inductor value, the second energy storage inductor voltage, and the second freewheeling inductor voltage. The steps of obtaining each corresponding second energy storage time and second freewheeling time using the first switching cycle and each second characteristic parameter include: obtaining the second energy storage time and the second freewheeling time using the first switching cycle, the second input current, the filter inductor value, the second energy storage inductor voltage, and the second freewheeling inductor voltage, respectively.

[0011] The second characteristic parameters also include a second dead time and a switching transistor output capacitor. The steps of obtaining the second energy storage time and the second freewheeling time using the first switching cycle, the second input current, the filter inductor value, the second energy storage inductor voltage, and the second freewheeling inductor voltage include: obtaining a first compensation coefficient using the first switching cycle and the filter inductor value; obtaining a second compensation coefficient using the first switching cycle, the second dead time, the filter inductor value, and the switching transistor output capacitor; and using a second adjustment function to calculate and process the second input current, the filter inductor value, the second energy storage inductor voltage, the second freewheeling inductor voltage, the first compensation coefficient, and the second compensation coefficient to obtain each corresponding second energy storage time and second freewheeling time. The calculation formula for the second adjustment function is as follows: ; ; ; Among them, I avg_D The second input current is given, L is the filter inductance, m is the first compensation coefficient, and U is the second input current. Lon_D U is the voltage of the second energy storage inductor. Loff_D The voltage of the second freewheeling inductor, T on_DCM1 For the initial energy storage time, T off_DCM1 T is the initial freewheeling time, k is the second compensation coefficient, and T is the initial freewheeling time. on_DCM For the second energy storage time, T off_DCM This is the second continuous flow time.

[0012] The step of obtaining the second compensation coefficient using the first switching cycle, the second dead time, the filter inductance value, and the output capacitance of the switching transistor includes: obtaining the first duration, the second duration, and the resonant period using the filter inductance value and the output capacitance of the switching transistor; using a third adjustment function to calculate and process the first switching cycle, the second dead time, the initial freewheeling time, the initial energy storage time, the first duration, the second duration, and the resonant period to obtain the total resonant time; and obtaining the second compensation coefficient using the total resonant time and the second dead time. The calculation formula for the third adjustment function is as follows: ; ; Among them, T LC For the resonant period, T TCM For the first switching cycle, T delay2 The second dead time, T1 is the first duration, T2 is the second duration, x is the number of resonant periods, and T... wait This is the total resonance time.

[0013] The second control signal includes a third drive signal and a fourth drive signal. The step of generating the second control signal using each corresponding second energy storage time and second freewheeling time includes: at the beginning of the second switching cycle of each second control signal, adjusting the third drive signal to a first level state; after the second energy storage time, adjusting the third drive signal from the first level state to the second level state; after a second dead time delay, adjusting the fourth drive signal from the second level state to the first level state; after the second freewheeling time, adjusting the fourth drive signal from the first level state to the second level state; or, in response to the second inductor current in each current discontinuity control phase crossing zero, adjusting the fourth drive signal from the first level state to the second level state.

[0014] The step of adjusting the fourth driving signal from the first level state to the second level state after the second freewheeling time further includes: after the total resonance time, entering the next second switching cycle, adjusting the third driving signal from the second level state to the first level state.

[0015] The step of adjusting the fourth drive signal from the first level state to the second level state after delaying for a second set time in response to the second inductor current crossing zero in each current discontinuous control phase further includes: in response to the second inductor current crossing zero for the 2nd (x+1)th time in each current discontinuous control phase, entering the next second switching cycle, adjusting the third drive signal from the second level state to the first level state.

[0016] Before the step of adjusting the fourth drive signal from the second level state to the first level state after delaying the second dead time, the method further includes: detecting whether the load rate of the three-phase conversion circuit is lower than a preset load threshold; if the load rate is lower than the preset load threshold, adjusting the fourth drive signal from the second level state to the first level state after delaying the sum of the second dead time, the second freewheeling time, the first duration, the second duration, and (x-1)*resonance period; and adjusting the fourth drive signal from the first level state to the second level state after the second set duration.

[0017] Before the step of adjusting the fourth driving signal from the second level state to the first level state after delaying the second dead time, the method further includes: detecting whether the second input current is within a preset threshold range; if the second input current is within the preset threshold range, adjusting the fourth driving signal from the second level state to the first level state after delaying the sum of the second dead time, the second freewheeling time, the first duration, the second duration, and the cumulative duration of (x-1)*resonance period; and adjusting the fourth driving signal from the first level state to the second level state after the second set duration.

[0018] The method further includes, after obtaining the first switching cycle using the first energy storage time and the first freewheeling time, and before generating the first control signal using the first energy storage time and the first freewheeling time, the following steps: detecting whether the first switching cycle is less than the minimum set cycle; if the first switching cycle is less than the minimum set cycle, generating the first control signal using the minimum set cycle, the first energy storage time, and the first freewheeling time; obtaining each corresponding limited on-time and limited off-time using the minimum set cycle and each second characteristic parameter; and generating a second control signal using each corresponding limited on-time and limited off-time.

[0019] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a control circuit, wherein the control circuit is used to couple with a three-phase conversion circuit; wherein the control circuit uses the control method of the three-phase conversion circuit as described in any of the above claims to control the three-phase conversion circuit.

[0020] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide an electronic device, wherein the electronic device includes a housing and a control circuit connected to the housing; wherein the control circuit is the control circuit described above.

[0021] The beneficial effects of this application are as follows: Unlike the prior art, the control method of the three-phase converter circuit provided in this application determines one phase of the three-phase converter circuit with the largest absolute value of the amplitude among the input voltages of phase A, phase B, and phase C as the delta current control phase, and determines the other two phases as the discontinuous current control phase. The first energy storage time, the first freewheeling time, and the first switching cycle are obtained using the first energy storage inductor voltage and the first freewheeling inductor voltage of the delta current control phase, so as to generate a first control signal for controlling the delta current control phase. The second energy storage time and the second freewheeling time are obtained using the first switching cycle and each second characteristic parameter, respectively, so as to generate a second control signal for controlling the discontinuous current control phase. This allows the three-phase converter circuit to operate in delta current mode or discontinuous current mode in a time-division manner. The switching frequency of the discontinuous current mode at each moment is within one resonant frequency of the switching frequency of the delta current mode, which naturally reduces the switching frequency range and eliminates the need for additional components. This makes it easier to realize zero-voltage turn-on and / or valley voltage turn-on of the three-phase converter circuit, thereby improving efficiency and reducing costs. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a flowchart illustrating the first embodiment of the control method for the three-phase conversion circuit of this application; Figure 2 This is a schematic diagram of the structure of the control circuit and three-phase conversion circuit of the first embodiment of this application; Figure 3 yes Figure 2 A waveform diagram of the A-phase input voltage, B-phase input voltage, and C-phase input voltage in an embodiment of a three-phase converter circuit; Figure 4 This is a flowchart illustrating the second embodiment of the control method for the three-phase conversion circuit of this application; Figure 5 This is a schematic diagram of the second embodiment of the control circuit and three-phase conversion circuit of this application; Figure 6 yes Figure 5 A waveform diagram of the relevant signals in the first embodiment of the three-phase converter circuit; Figure 7 yes Figure 4 A flowchart illustrating an embodiment of S58; Figure 8 yes Figure 4A flowchart illustrating an embodiment of S59; Figure 9 yes Figure 8 A flowchart illustrating an embodiment of S592; Figure 10 yes Figure 4 A flowchart illustrating the first embodiment of S510; Figure 11 yes Figure 5 A waveform diagram of the relevant signals in the second embodiment of the three-phase converter circuit; Figure 12 yes Figure 4 A flowchart illustrating the second embodiment of S510; Figure 13 yes Figure 5 A waveform diagram of the relevant signals in the three-phase converter circuit according to the third embodiment; Figure 14 yes Figure 4 A flowchart illustrating the third embodiment of S510; Figure 15 This is a flowchart illustrating the third embodiment of the control method for the three-phase conversion circuit of this application; Figure 16 This is a schematic diagram of one embodiment of the electronic device of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] The terms "first," "second," and "third" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0025] In this document, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations. It will be explicitly and implicitly understood by those skilled in the art that the implementations described herein can be combined with other implementations.

[0026] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] Please refer to the following: Figure 1 and Figure 2 ,in, Figure 1 This is a flowchart illustrating the first embodiment of the control method for the three-phase converter circuit of this application. Figure 2 This is a schematic diagram of the first embodiment of the control circuit and three-phase conversion circuit of this application. Specifically, it may include the following steps: S11: Obtain the A-phase input voltage, B-phase input voltage, and C-phase input voltage of the three-phase converter circuit.

[0028] It is understandable that the control method of the three-phase conversion circuit 30 in this embodiment is specifically applied to, for example... Figure 2 In the drive control of the three-phase converter circuit 30 shown; wherein, the control circuit 20 is coupled to the three-phase converter circuit 30 to drive the three-phase converter circuit 30 using the control method of the three-phase converter circuit 30 described in any one of the present invention.

[0029] It is worth noting that the three-phase conversion circuit 30 can specifically be a conversion circuit that receives three-phase grid power, adjusts and converts it, and then supplies power to the load circuit.

[0030] The power grid is a comprehensive power network system connecting power generation, transmission, distribution, and consumption. Its core function is to achieve safe and efficient transmission and dynamic balance control of electrical energy. Three-phase is the most common type of multiphase alternating current system, which can be divided into symmetrical and asymmetrical three-phase systems. A symmetrical three-phase power supply consists of three sinusoidal voltage sources with equal amplitude, frequency, and initial phases differing by 120°, connected in a star (Y) or delta (△) configuration. These three sources are referred to as phase A, phase B, and phase C, respectively. It has the advantage of facilitating power transmission and is the basic method of power supply and transmission.

[0031] The phase sequence (order) A, B, C of the three-phase voltages mentioned above is called the positive sequence or forward sequence. The opposite is called the reverse sequence or inverse sequence. Power systems generally use the positive sequence.

[0032] Symmetrical three-phase voltages satisfy the following conditions: ua + ub + uc = 0, or phasor representation: + + =0; The symmetrical three-phase voltage is provided by a three-phase generator.

[0033] Furthermore, in a three-phase circuit, any circuit with even a partial asymmetry is called an asymmetrical three-phase circuit. In a three-phase circuit, the complex power absorbed by the three-phase load is equal to the sum of the complex powers of each phase. The instantaneous power of a three-phase circuit is the sum of the instantaneous power of each phase load. In a three-phase three-wire circuit, regardless of symmetry, two wattmeters can be used to measure the three-phase power, i.e., the two-wattmeter method.

[0034] In this document, "coupled" refers to any direct or indirect connection. Therefore, if the document describes a first circuit coupled to a second circuit, it means that the first circuit can be directly connected to the second circuit via electrical connection or signal connection methods such as wireless transmission or optical transmission, or indirectly connected to the second circuit via other circuits or connection methods via electrical connection or signal connection.

[0035] In some embodiments, the three-phase conversion circuit 30 may be a two-level three-phase three-wire rectifier or inverter circuit, a two-level three-phase four-wire rectifier or inverter circuit, a multi-channel interleaved rectifier or inverter circuit, or any other reasonable circuit topology. This embodiment does not limit this.

[0036] In some embodiments, the control circuit 20 may specifically include any reasonable circuit unit with signal processing function, such as a control chip, a DSP (Digital Signal Processing) chip, an MCU (Micro Controller Unit) circuit, a CPU (Central Processing Unit), a microcontroller, a field-programmable gate array, a programmable logic device, a discrete gate or transistor logic device, or discrete hardware. This application does not limit the scope of the application.

[0037] Specifically, the control circuit 20 is used to sample and obtain the A-phase input voltage Ua, B-phase input voltage Ub and C-phase input voltage Uc provided by the three-phase grid power supply from the three-phase conversion circuit 30.

[0038] In some embodiments, the A-phase input voltage Ua, B-phase input voltage Ub, and C-phase input voltage Uc can be obtained by one or more of any reasonable sampling methods, such as voltage transformers, sampling resistors, ADCs (analog to digital converters), Hall sensors, or circuit model estimation. This application does not limit the specific sampling methods used.

[0039] S12: Determine one phase of the three-phase converter circuit corresponding to the one with the largest absolute value of the amplitude among the input voltages of phase A, phase B, and phase C as the triangular current control phase.

[0040] Understandably, since the initial phase input voltages Ua, Ub, and Uc of phase A are 120° out of phase and are sinusoidal voltages, within a complete sinusoidal cycle with phase A input voltage Ua as the reference, the absolute values ​​of the amplitudes of phase A input voltage Ua, phase B input voltage Ub, and phase C input voltage Uc will exhibit different magnitude comparison orders, and there will also be a distinction between positive and negative voltage amplitudes.

[0041] Specifically, the absolute values ​​of the amplitudes of every two of the currently acquired A-phase input voltage Ua, B-phase input voltage Ub, and C-phase input voltage Uc are compared, and the phase in the three-phase conversion circuit 30 corresponding to the one with the largest absolute amplitude value is determined as the triangular current control phase.

[0042] S13: Determine the other two phases in the three-phase conversion circuit as current discontinuous control phases.

[0043] Furthermore, the two phases in the three-phase converter circuit 30 corresponding to the two phases with the middle and smallest absolute values ​​of the amplitudes of the phase A input voltage Ua, phase B input voltage Ub, and phase C input voltage Uc are determined as the current discontinuous control phases.

[0044] For ease of understanding, let's take the three-phase converter circuit 30 as an example, specifically including a three-phase switching circuit, which further includes an A-phase switching sub-circuit, a B-phase switching sub-circuit, and a C-phase switching sub-circuit, corresponding to the A-phase input voltage Ua, the B-phase input voltage Ub, and the C-phase input voltage Uc, respectively. The B-phase input voltage Ub has the largest absolute amplitude, and the C-phase input voltage Uc has a larger absolute amplitude than the A-phase input voltage Ua. Therefore, the B-phase switching sub-circuit will be designated as the triangular current control phase and will be controlled using TCM (Triangular Current Mode). The C-phase switching sub-circuit and the A-phase switching sub-circuit will be designated as discontinuous current control phases and will be controlled using DCM (Discontinuous Current Mode). The control is achieved through a current discontinuous mode. When the absolute values ​​of the amplitudes of the input voltages Ua (phase A), Ub (phase B), and Uc (phase C) change, the A-phase, B-phase, and C-phase switching sub-circuits will redetermine their correspondence with the delta current control phase and the current discontinuous control phase, respectively, to switch to different control modes to drive and control the switching circuits of each phase. This will not be elaborated further here.

[0045] Understandably, the dynamic allocation mechanism described above enables each phase to execute the most suitable control strategy based on the input voltage state, which can effectively improve overall efficiency and stability.

[0046] It is worth noting that the current characteristics of TCM belong to a subclass of critical conduction mode. The inductor current rises from zero to a peak value in each cycle, then drops to zero until a negative preset current value, and then returns to zero, with no zero current sustaining phase (dead time is close to zero). Waveform characteristics: The current is a triangular wave, and returns strictly to zero at the end of the cycle.

[0047] The current characteristics of a DCM (Diverterless Computing) are as follows: the inductor current drops to zero and remains at zero for a period of time during each switching cycle (zero current sustaining phase). The current waveform exhibits a discontinuous state of "rise-fall-return to zero". Waveform characteristics: the current rises from zero to a peak value, then falls back to zero, and subsequently enters a "dead time" with no current.

[0048] S14: Obtain the first characteristic parameter of the triangular current control phase and the second characteristic parameter of each current discontinuous control phase.

[0049] Specifically, the first characteristic parameter of the switching sub-circuit currently determined as the triangular current control phase in the three-phase conversion circuit 30, such as the B-phase switching sub-circuit, is obtained. This parameter could be one or more of any reasonable electrical parameters, such as the filter inductance value, the instantaneous value of the B-phase input voltage Ub, or the output voltage. This application does not limit the specific parameters in this regard.

[0050] Furthermore, the second characteristic parameters of the switching sub-circuits currently determined as the current discontinuous control phase in the three-phase conversion circuit 30, such as the C-phase switching sub-circuit and the A-phase switching sub-circuit, are obtained respectively. These parameters include one or more of any reasonable electrical parameters such as the instantaneous value of the C-phase input voltage Uc, the instantaneous value of the A-phase input voltage Ua, and the output capacitance of the switching transistor. This application does not limit the specific parameters in this regard.

[0051] It is worth noting that since there are two phase switching sub-circuits that correspond to the current discontinuous control phases, the second characteristic parameters of these two phase switching sub-circuits are different. However, the control strategies corresponding to these two phase switching sub-circuits, i.e. the subsequent calculation and processing procedures and formulas, are the same. For ease of explanation, no distinction is made in the names, but the actual parameters are different, which will not be elaborated here.

[0052] In this embodiment, the first characteristic parameter may specifically include the first energy storage inductor voltage and the first freewheeling inductor voltage.

[0053] S15: The first energy storage time and the first freewheeling time are obtained using the first energy storage inductor voltage and the first freewheeling inductor voltage.

[0054] The first energy storage time and the first freewheeling time are obtained by processing the first energy storage inductor voltage and the first freewheeling inductor voltage using a preset control program or adjustment function.

[0055] S16: The first switching cycle is obtained by utilizing the first energy storage time and the first freewheeling time.

[0056] The first switching cycle is obtained by adding the first energy storage time to the first freewheeling time; or, the first switching cycle is obtained by adding the first energy storage time to the first freewheeling time and then adding the first dead time.

[0057] It is worth noting that the first dead time and the second dead time mentioned later refer to the time interval between the change in the input signal and the change in the output signal when the corresponding switching transistor switches, or the time obtained by reasonably setting this time interval. In switching power supplies, in order to avoid current surges caused by the simultaneous conduction of push-pull transistors, the control circuit 20 sets a dead time between switching operations to keep the transistor in the off state.

[0058] S17: Generate a first control signal using the first energy storage time and the first freewheeling time.

[0059] It is understandable that the first energy storage time and the first freewheeling time correspond to the duration of the energy storage tube and the freewheeling tube in the triangular current control phase being triggered to conduct, respectively. They can also be understood as the turn-on time and the turn-off time, respectively, and correspond to the duration of the high and low levels of the first control signal.

[0060] Under normal circumstances, without considering the dead time, the end time of the first freewheeling time is the end time of the first switching cycle, and corresponds to the start time of the next first switching cycle.

[0061] Specifically, the level state is adjusted in response to the currently acquired first energy storage time and first freewheeling time to generate a first control signal.

[0062] S18: The second energy storage time and the second freewheeling time are obtained by using the first switching cycle and each second characteristic parameter.

[0063] A preset control program or adjustment function is used to process the first switching cycle and each second characteristic parameter to obtain the second energy storage time and the second freewheeling time corresponding to each current discontinuous control.

[0064] S19: Generate a second control signal using each corresponding second energy storage time and second freewheeling time.

[0065] In response to each current discontinuous control, the level state is adjusted according to the corresponding second energy storage time and second freewheeling time to generate a second control signal.

[0066] S110: Send the first control signal and each of the second control signals to the delta current control phase and each of the current discontinuous control phases respectively, so as to trigger the delta current control phase and each of the current discontinuous control phases to change the switching state respectively.

[0067] The first control signal is sent to the delta current control phase, and at the same time, each second control signal is sent to the two current discontinuous control phases respectively, so as to trigger the relevant switching elements inside the delta current control phase and each current discontinuous control phase to change the switching state, thereby adjusting the output voltage and / or output current of the three-phase conversion circuit 30.

[0068] For example, when the B-phase switch sub-circuit is a delta current control phase, and the A-phase switch sub-circuit and the C-phase switch sub-circuit are both current discontinuous control phases, the currently generated first control signal is sent to the B-phase switch sub-circuit, and each second control signal is sent to the A-phase switch sub-circuit and the C-phase switch sub-circuit respectively, so as to trigger the relevant internal switching elements to change the switching state, thereby adjusting the output voltage and / or output current of the three-phase conversion circuit 30.

[0069] It is worth noting that the signal frequency of the A-phase input voltage Ua is much lower than the signal frequencies of the first control signal and each of the second control signals. Within a complete sine wave cycle with the A-phase input voltage Ua as the reference, there will be multiple cycle stages where the absolute values ​​of the amplitudes of the A-phase input voltage Ua, B-phase input voltage Ub, and C-phase input voltage Uc have different magnitude orders. These different magnitude orders will correspond to different relationships between the A-phase switch sub-circuit, B-phase switch sub-circuit, and C-phase switch sub-circuit and the delta current control phase and the current discontinuous control phase, respectively. In each cycle stage, the first control signal and each of the second control signals are continuously sent to the delta current control phase and the current discontinuous control phase according to the currently determined relationship, until the relationship changes and the next cycle stage begins. The transmission mode of the control signals of each phase switch sub-circuit is then readjusted, which will not be elaborated further here.

[0070] The above scheme utilizes the first energy storage inductor voltage and the first freewheeling inductor voltage of the triangular current control phase to obtain the first energy storage time, the first freewheeling time, and the first switching cycle, thereby generating a first control signal to control the triangular current control phase. It then uses the first switching cycle and each second characteristic parameter to obtain the corresponding second energy storage time and second freewheeling time, generating a second control signal to control the discontinuous current control phase. This allows the three-phase converter circuit to operate in triangular current mode or discontinuous current mode for 30 time intervals. The switching frequency of the discontinuous current mode differs from that of the triangular current mode by a resonant frequency at each moment, naturally reducing the switching frequency range. Furthermore, it eliminates the need for additional components, facilitating the implementation of ZVS (Zero Voltage Switching) for all 30 phases of the three-phase converter circuit. It also enables full-range ZVS or valley voltage switching within the power frequency cycle, improving efficiency and reducing costs. The naturally limited switching frequency range enhances product efficiency and power density, reduces the size of the filter inductor, and improves EMI (Electromagnetic Interference) design and performance, further reducing product costs.

[0071] Furthermore, in some embodiments, the above-mentioned S12 specifically includes: in each signal cycle of the A-phase input voltage Ua, dividing the signal cycle into the first to the sixth sector by using the amplitude comparison results between every two of the A-phase input voltage Ua, B-phase input voltage Ub and C-phase input voltage Uc.

[0072] Please continue reading. Figure 3 , Figure 3 yes Figure 2 A waveform diagram of the A-phase input voltage, B-phase input voltage, and C-phase input voltage in an embodiment of a three-phase converter circuit.

[0073] Understandably, since the initial phases of the input voltages Ua (phase A), Ub (phase B), and Uc (phase C) are 120° out of phase and are sinusoidal, within a complete sinusoidal cycle with Ua as the reference, the absolute values ​​of their amplitudes will exhibit different orderings, and there will also be a distinction between positive and negative amplitudes. To differentiate these, in each signal cycle of Ua (phase A), the signal cycle can be divided into sectors one through six based on the different amplitude comparison results between any two of the input voltages Ua (phase A), Ub (phase B), and Uc (phase C).

[0074] Each sector can be understood as a different periodic stage of each signal cycle of the A-phase input voltage Ua. In different periodic stages, the A-phase switch sub-circuit, B-phase switch sub-circuit, and C-phase switch sub-circuit will have different correspondences with the delta current control phase and the current discontinuous control phase, respectively. However, in the same periodic stage, that is, in the same sector, the correspondence remains unchanged.

[0075] In the first to sixth sectors, the delta current control phase and each discontinuous current control phase in the three-phase converter circuit 30 are determined by sorting the absolute values ​​of the amplitudes of the A-phase input voltage Ua, B-phase input voltage Ub, and C-phase input voltage Uc, respectively.

[0076] Understandably, the input voltage Ua of phase A is divided into six sectors based on the voltage phase: 0°~60°, 60°~120°, 120°~180°, 180°~240°, 240°~300°, and 300°~360°. Within each sector, the phase with the largest absolute amplitude value is selected as the TCM mode, while the other two phases are selected as the DCM mode. The modulation method selects control strategies such as SPWM (Pulse Width Modulation) and SVPWM (Space Vector Pulse Width Modulation).

[0077] Please see Figure 4 , Figure 4 This is a flowchart illustrating the second embodiment of the control method for the three-phase converter circuit of this application. The control method for the three-phase converter circuit in this embodiment... Figure 1 A detailed implementation diagram of the control method for the three-phase converter circuit is shown, which specifically includes the following steps: S51: Obtain the A-phase input voltage, B-phase input voltage, and C-phase input voltage of the three-phase converter circuit.

[0078] S52: Determine one phase of the three-phase converter circuit corresponding to the one with the largest absolute value of the amplitude among the input voltages of phase A, phase B, and phase C as the triangular current control phase.

[0079] S53: Determine the other two phases in the three-phase conversion circuit as current discontinuous control phases.

[0080] S54: Obtain the first characteristic parameter of the triangular current control phase and the second characteristic parameter of each current discontinuous control phase.

[0081] Among them, S51, S52, S53 and S54 and Figure 1 S11, S12, S13 and S14 are the same. Please refer to the textual descriptions of S11, S12, S13 and S14 and their related texts for details. They will not be repeated here.

[0082] S55: The first energy storage inductor voltage and the first freewheeling inductor voltage are obtained using the first input voltage, the first output reference voltage, the second output reference voltage, and the first filter capacitor voltage.

[0083] Please continue reading. Figure 5 and Figure 6 ,in, Figure 5 This is a schematic diagram of the second embodiment of the three-phase converter circuit of this application. Figure 6 yes Figure 5 A waveform diagram of the relevant signals in the three-phase converter circuit of the first embodiment.

[0084] It is understood that the control method for the three-phase conversion circuit in this embodiment can also specifically be a control circuit (not shown in the figure) that controls, for example... Figure 5 The three-phase conversion circuit 40 shown implements control to supply power to the load circuit (not shown) after the three-phase system power supply 101 is regulated and controlled by the three-phase conversion circuit 40. The three-phase conversion circuit 40 includes a three-phase capacitor circuit 41, a three-phase inductor circuit 42, a three-phase switching circuit 43, and a regulated output circuit 44. The three-phase capacitor circuit 41 includes a first capacitor C1, a second capacitor C2, and a third capacitor C3. The three-phase switching circuit 43 includes an A-phase switching sub-circuit 431, a B-phase switching sub-circuit 432, and a C-phase switching sub-circuit 433. The three-phase inductor circuit 42 includes an A-phase inductor L1, a B-phase inductor L2, and a C-phase inductor L3. The A-phase switching sub-circuit 431 includes a first switch S1 and a second switch S2. The B-phase switching sub-circuit 432 includes a third switch S3 and a fourth switch S4. The C-phase switching sub-circuit 433 includes a fifth switch S5 and a sixth switch S6. The regulated output circuit 44 includes a first output capacitor C11 and a second output capacitor C12.

[0085] In this configuration, the first terminal of phase A inductor L1 is coupled to the first terminal of the first capacitor C1 and is used to couple to the first terminal of the three-phase power supply 101; the first terminal of phase B inductor L2 is coupled to the first terminal of the second capacitor C2 and is used to couple to the second terminal of the three-phase power supply 101; the first terminal of phase C inductor L3 is coupled to the first terminal of the third capacitor C3 and is used to couple to the third terminal of the three-phase power supply 101; the second terminal of phase A inductor L1 is coupled to the second terminal of the first switch S1 and the third terminal of the second switch S2; the second terminal of phase B inductor L2 is coupled to the second terminal of the third switch S3 and the third terminal of the fourth switch S4; and the second terminal of phase C inductor L3 is coupled to the fifth switch S4. The second terminal of switch S5 and the third terminal of switch S6 are connected. The third terminal of first switch S1 is coupled to the third terminal of third switch S3, the third terminal of fifth switch S5, and the first terminal of first output capacitor C11, and is used to couple to the first terminal of the load circuit. The second terminal of second switch S2 is coupled to the second terminal of fourth switch S4, the second terminal of sixth switch S6, and the second terminal of second output capacitor C12, and is used to couple to the second terminal of the load circuit. The second terminal of first output capacitor C11 is coupled to the first terminal of second output capacitor C12, the second terminal of first capacitor C1, the second terminal of second capacitor C2, and the second terminal of third capacitor C3. This control circuit is coupled to the first terminal of first switch S1, the first terminal of second switch S2, the first terminal of third switch S3, the first terminal of fourth switch S4, the first terminal of fifth switch S5, and the first terminal of sixth switch S6.

[0086] In some embodiments, the first switch S1, the second switch S2, the third switch S3, the fourth switch S4, the fifth switch S5, and the sixth switch S6 may specifically be one of a MOSFET (Metal Oxide Semiconductor Field-Effect Transistor), a transistor, a thin-film transistor, a field-effect transistor, or any other reasonable switch, so as to trigger the conduction or deactivation of its second and third terminals when a control signal sent by the control circuit is received at its first terminal. This application does not limit this.

[0087] In other embodiments, the three-phase conversion circuit 40 can be any reasonable circuit topology, such as a two-level three-phase four-wire rectifier or inverter circuit, a multi-channel interleaved rectifier or inverter circuit, or a two-channel interleaved two-level three-phase three-wire rectifier or inverter circuit. This embodiment does not limit it in this way.

[0088] In another embodiment, the three-phase conversion circuit 40 may further include a filter circuit 45, and the filter circuit 45 is specifically coupled between the three-phase system power supply 101 and the A-phase inductor L1, B-phase inductor L2, and C-phase inductor L3. This embodiment does not limit this.

[0089] It is worth noting that, according to the timing of the three-phase conversion circuit 40, when the input voltage of a certain phase in the three-phase power supply 101 is greater than zero, the lower tube of the corresponding bridge arm is the energy storage tube and the upper tube is the freewheeling tube; conversely, the upper tube of the corresponding bridge arm is the energy storage tube and the lower tube is the freewheeling tube. For example, when the input voltage Ua of phase A is greater than zero, the second switch S2 is the first energy storage transistor and the first switch S1 is the first freewheeling transistor; when the input voltage Ua of phase A is less than zero, the first switch S1 is the first energy storage transistor and the second switch S2 is the first freewheeling transistor. Similarly, when the input voltage Ub of phase B is greater than zero, the fourth switch S4 is the second energy storage transistor and the third switch S3 is the second freewheeling transistor; when the input voltage Ub of phase B is less than zero, the third switch S3 is the second energy storage transistor and the fourth switch S4 is the second freewheeling transistor. When the input voltage Uc of phase C is greater than zero, the sixth switch S6 is the third energy storage transistor and the fifth switch S5 is the third freewheeling transistor; when the input voltage Uc of phase C is less than zero, the fifth switch S5 is the third energy storage transistor and the sixth switch S6 is the third freewheeling transistor.

[0090] Specifically, the first characteristic parameter sampled by the control circuit may further include acquiring the first input voltage U1 and the first output reference voltage U. up Second output reference voltage U dn The voltage U of the first filter capacitor C1 First input current I avg_T And the filter inductance value L, so as to use a preset control program or adjustment function to adjust the first input voltage U1 and the first output reference voltage U. up Second output reference voltage U dn The voltage U of the first filter capacitor C1 First input current I avg_T The voltage U of the first energy storage inductor is obtained by processing the filter inductance value L. Lon_T and the first freewheeling inductor voltage U Loff_T .

[0091] It is worth noting that the filter inductance value L is the design inductance value of any one of the A-phase inductance L1, B-phase inductance L2, and C-phase inductance L3, and usually the design inductance values ​​of A-phase inductance L1, B-phase inductance L2, and C-phase inductance L3 are the same.

[0092] In addition, the first input voltage U1 and the first output reference voltage U up Second output reference voltage U dn The voltage U of the first filter capacitor C1The voltage sample value; and the first input voltage U1 is specifically determined to be the instantaneous voltage value corresponding to the largest absolute value among the A-phase input voltage Ua, B-phase input voltage Ub, and C-phase input voltage Uc corresponding to the triangular current control; the first output reference voltage U up The voltage at the midpoint of the positive bus reference bus is the second output reference voltage U. dn The voltage of the reference negative bus is the midpoint of the bus; the voltage of the first filter capacitor is U. C1 The voltage across the terminals of the one of the three capacitors C1, C2, and C3 that is identified as the triangular current control phase.

[0093] S56: The first energy storage time and the first freewheeling time are obtained using the first energy storage inductor voltage, the first freewheeling inductor voltage, the first input current, and the filter inductor value.

[0094] Furthermore, a preset control program or adjustment function is used to adjust the currently acquired first energy storage inductor voltage U. Lon_T First freewheeling inductor voltage U Loff_T First input current I avg_T The first energy storage time T is obtained by processing the filter inductance value L. on_TCM and the first continuous time T off_TCM .

[0095] S57: The first switching cycle is obtained by utilizing the first energy storage time and the first freewheeling time.

[0096] S58: Generate a first control signal using the first energy storage time and the first freewheeling time.

[0097] S59: The second energy storage time and the second freewheeling time are obtained by using the first switching cycle and each second characteristic parameter, respectively.

[0098] S510: Generate a second control signal using each corresponding second energy storage time and second freewheeling time.

[0099] S511: Send the first control signal and each of the second control signals to the delta current control phase and each of the current discontinuous control phases respectively, so as to trigger the delta current control phase and each of the current discontinuous control phases to change the switching state respectively.

[0100] Among them, S57, S58, S59, S510 and S511 and Figure 1 S16, S17, S18, S19 and S110 are the same. For details, please refer to S11, S12, S13 and S14 and their related textual descriptions. They will not be repeated here.

[0101] Furthermore, in some embodiments, the first characteristic parameter specifically includes input power, a first input voltage, and the effective value of the input phase voltage. Prior to S56, it may further include: utilizing the input power P, the first input voltage U1, and the effective value of the input phase voltage U... rms Obtain the first input current I avg_T .

[0102] Understandably, the first input current I avg_T Specifically, this can be achieved by adjusting the input power P, the first input voltage U1, and the effective value of the input phase voltage U. rms The corresponding function calculation is performed to obtain the calculated value, which is determined by the input power P or the control loop. This allows for a simpler three-phase conversion circuit control method under conditions without current sampling, with higher accuracy and smaller total harmonic distortion of the AC current.

[0103] Among them, the input power P and the effective value of the input phase voltage U rms It can be a preset constant value that is fitted based on power supply requirements and simulation experimental data.

[0104] In other embodiments, the first input current I avg_T Specifically, it can also be obtained by directly sampling the inductor current of one of the three phases of inductor L1 (A phase), inductor L2 (B phase), and inductor L3 (C phase) that is determined to be the triangular current control phase. The corresponding current sampling value is not limited in this application.

[0105] Furthermore, in some embodiments, the first characteristic parameter specifically includes setting a negative current I. R Specifically, S56 may further include: using a first adjustment function to adjust the voltage U of the first energy storage inductor. Lon_T First freewheeling inductor voltage U Loff_T First input current I avg_T , filter inductance value L and set negative current I R The first energy storage time T is obtained through calculation. on_TCM and the first continuous time T off_TCM ; The calculation formula for the first adjustment function is as follows: ; ; Among them, T on_TCM For the first energy storage time, T off_TCM For the first continuous flow time, I avg_T For the first input current, I R To set the negative current, L is the value of the filter inductance, and U... Lon_T U is the voltage of the first energy storage inductor.Loff_T This is the voltage of the first freewheeling inductor.

[0106] Furthermore, in some embodiments, the second characteristic parameter specifically includes a second input current I. avg_D , filter inductance value L, second energy storage inductor voltage U Lon_D The second freewheeling inductor voltage U Loff_D Specifically, S59 may further include: utilizing the first switching cycle T TCM Second input current U2, filter inductance value L, second energy storage inductor voltage U Lon_D The second freewheeling inductor voltage U Loff_D The corresponding second energy storage time T is obtained respectively. on_DCM Second continuous current time T off_DCM .

[0107] It is worth noting that the voltage U of the second energy storage inductor Lon_D Second freewheeling inductor voltage U Loff_D Specifically, this can also be achieved by adjusting the second input voltage U2 and the first output reference voltage U. up Second output reference voltage U dn and the voltage U of the second filter capacitor C2 The second input voltage U2 is calculated as a function, or determined by the input voltage and the output voltage; while the second input voltage U2 and the second filter capacitor voltage U... C2 The second input voltage U2 is obtained through corresponding voltage sampling, and is specifically determined to be the two instantaneous voltage values ​​with smaller absolute values ​​among the A-phase input voltage Ua, B-phase input voltage Ub, and C-phase input voltage Uc corresponding to the current discontinuous control; the second filter capacitor voltage U C2 The voltage across the two capacitors that are identified as the current discontinuous control phase among the first capacitor C1, the second capacitor C2, and the third capacitor C3 is given.

[0108] In some embodiments, the second input current I avg_D Specifically, this can be obtained by directly sampling the inductor currents of the two inductors corresponding to the current discontinuous control phases among the A-phase inductor L1, B-phase inductor L2, and C-phase inductor L3. The corresponding current sampling values ​​are also obtained by sampling the input power P, the second input voltage U2, and the effective value of the input phase voltage U. rms The corresponding function calculation is performed to obtain the calculated value, or it is determined by the input power P or the control loop, so as to realize a three-phase conversion circuit control method with a simpler calculation method under the condition of no current sampling, and the calculation result has high accuracy and small total harmonic distortion of AC current. This application does not limit this.

[0109] Please continue reading. Figure 7 , Figure 7 yes Figure 4 A flowchart illustrating an embodiment of S58 is provided. In one embodiment, the control method for the three-phase conversion circuit of this application, in addition to the above-described S51-S511, further includes some more specific steps. Specifically, S58 may further include the following steps: S581: At the beginning of the first switching cycle, adjust the first drive signal to the first level state.

[0110] Specifically, the first control signal includes a first drive signal PWM1 and a second drive signal PWM2; when the second switch S2 is an energy storage tube and the first switch S1 is a freewheeling tube, the first drive signal PWM1 and the second drive signal PWM2 correspond to the drive control signals of the second switch S2 and the first switch S1, respectively; and when the first switch S1 is an energy storage tube and the second switch S2 is a freewheeling tube, the first drive signal PWM1 and the second drive signal PWM2 correspond to the drive control signals of the first switch S1 and the second switch S2, respectively.

[0111] Specifically, such as Figure 6 As shown in (a), after obtaining the first energy storage time T on_TCM First continuous flow time T off_TCM First dead zone time T delay1 First switching cycle T TCM Subsequently, in each first switching cycle T of the first control signal TCM At the start time, i.e., time t0, the first drive signal PWM1 is adjusted to the first level state.

[0112] Specifically, the first level state can be a high level and the second level state can be a low level; however, in other embodiments, the first level state can also be a low level and the second level state can be a high level, and this application does not limit this.

[0113] S582: After the first energy storage time, adjust the first drive signal from the first level state to the second level state.

[0114] First energy storage time T on_TCM Then, at time t11, the first drive signal PWM1 is adjusted from the first level state to the second level state.

[0115] S583: After a first dead time delay, adjust the second drive signal from the second level state to the first level state.

[0116] Delay first dead zone time T delay1 Then, after time t12, and after another turn-on delay, the second drive signal PWM2 is adjusted from the second level state to the first level state.

[0117] S584: After the first freewheeling time, adjust the second drive signal from the first level state to the second level state.

[0118] First continuous flow time T off_TCM Then, at time t14, the second drive signal PWM2 is adjusted from the first level state to the second level state.

[0119] The implementation principle of triangular current control phase is understandable: such as... Figure 6 As shown in (a), with the first inductor current i L1 Taking the case where the current is greater than zero as an example, the second switch S2 is an energy storage transistor, and the first switch S1 is a freewheeling transistor. During the time period t0-t11, the second switch S2 is turned on, the first switch S1 is turned off, and the first inductor current i... L1 The current increases linearly, the second switch S2 is turned off at time t11, and the first inductor current i L1 The peak value is reached; the first dead zone time T is the period from t11 to t12. delay1 The second switch S2 and the first switch S1 are both turned off. Then the parallel filter capacitors of the second switch S2 and the first switch S1 are charged and discharged respectively. After a short resonance process, the parallel filter capacitor of the first switch S1 is completely discharged to 0V, and the body diode of the first switch S1 is turned on at time t12.

[0120] If the first switch S1 is turned on after t12, ZVS of the first switch S1 can be achieved; during the t12-t13 period, the second switch S2 is turned off and the first switch S1 is turned on, and the first inductor current i L1 The current begins to decrease; the period from t13 to t14 is the turn-on delay time of the first switch S1, while the second switch S2 remains off until t14 when the first switch S1 turns off. At this time, the first inductor current i L1 It will continue to drop to the set negative current I R During the period t14-t15, both the second switch S2 and the first switch S1 are turned off, and the resonance process begins again. When the output capacitor of the second switch S2 discharges to 0V at time t15, the body diode of the second switch S2 turns on. During the period t15-t16, the first inductor current i... L1 Gradually from the set negative current I R If the current of the first inductor, i, rises to 0A, at time t16... L1 By turning on the second switch S2 before it becomes positive, ZVS of the second switch S2 can be achieved, and the next first switching cycle T can begin. TCM .

[0121] Furthermore, in some embodiments, the above-mentioned S584 can be specifically replaced by: responding to the first inductor current i in the triangular current control phase.L1 Upon zero crossing, a first set time delay is applied to adjust the second drive signal from the first level state to the second level state.

[0122] It is understood that the control circuit may further include a zero-crossing detection circuit (not shown in the figure), which is used to perform zero-crossing detection on the A-phase inductor current iLa, the B-phase inductor current iLb, and the C-phase inductor current iLc respectively, or on the first inductor current i in the currently determined triangular current control phase. L1 For example, the B-phase inductor current iLb in the first sector is zero-crossing detected, so that after the zero-crossing moment of the inductor current iLb is detected, the second drive signal PWM2 is adjusted from the first level state to the second level state after a first set time delay.

[0123] The specific duration of the first setting can be obtained by fitting data from actual application scenarios, and this application does not limit it.

[0124] It is worth noting that, due to unavoidable sampling errors and signal interference in the actual control of the three-phase conversion circuit 30, the first energy storage time T calculated theoretically may vary. on_TCM and the first continuous time T off_TCM There is usually a certain degree of error, which causes the first freewheeling time T to be... off_TCM The termination time does not actually correspond to the first inductor current i. L1 The zero-crossing time is not accurately determined, thus failing to effectively guarantee zero-voltage turn-on. Therefore, a zero-crossing detection circuit can be used to correct the calculation error, thereby detecting the first inductor current i. L1 The actual zero-crossing time, and the delay of the first set duration, is determined as the first continuous flow time T. off_TCM The termination time, i.e. the falling edge, allows for more effective zero-voltage turn-on.

[0125] Please continue reading. Figure 8 , Figure 8 yes Figure 4 A flowchart illustrating an embodiment of S59 is provided. In one embodiment, the control method for the three-phase conversion circuit of this application, in addition to the above-described S51-S511, further includes some more specific steps. Specifically, S59 may further include the following steps: S591: The first compensation coefficient is obtained using the first switching cycle and the value of the filter inductance.

[0126] Specifically, a first compensation coefficient is obtained by calculating the first switching cycle and the filter inductance value using a preset function. Specifically, the first compensation coefficient can be obtained by setting the first switching cycle and the filter inductance value as independent variables in a simulation experiment, continuously adjusting the independent variables to obtain corresponding simulation experiment data, or by obtaining statistical data from actual application scenarios, and then analyzing and fitting the simulation experiment data and / or statistical data to obtain the first compensation coefficient, or by using a corresponding preset function to calculate the first compensation coefficient; or it can be determined by the power and control loop, which is not limited in this application.

[0127] S592: The second compensation coefficient is obtained by using the first switching cycle, the second dead time, the filter inductance value, and the output capacitor of the switching transistor.

[0128] Furthermore, a second compensation coefficient is obtained by calculating the first switching cycle, the second dead time, the filter inductance value, and the output capacitance of the switching transistor using a preset function. Specifically, this can be achieved by setting the first switching cycle, the second dead time, the filter inductance value, and the output capacitance of the switching transistor as independent variables in a simulation experiment, continuously adjusting these independent variables to obtain corresponding simulation experimental data, or by obtaining statistical data from actual application scenarios, and then analyzing and fitting the simulation experimental data and / or statistical data to obtain the second compensation coefficient, or by using a corresponding preset function to calculate the second compensation coefficient; or by being determined by the power and control loop, which is not limited in this application.

[0129] S593: The second adjustment function is used to calculate and process the second input current, filter inductor value, second energy storage inductor voltage, second freewheeling inductor voltage, first compensation coefficient and second compensation coefficient to obtain the corresponding second energy storage time and second freewheeling time.

[0130] The calculation formula for the second adjustment function is as follows: ; ; ; Among them, I avg_D The second input current is given, L is the filter inductance, m is the first compensation coefficient, and U is the second input current. Lon_D U is the voltage of the second energy storage inductor. Loff_D The voltage of the second freewheeling inductor, T on_DCM1 For the initial energy storage time, T off_DCM1 T is the initial freewheeling time, k is the second compensation coefficient, and T is the initial freewheeling time. on_DCM For the second energy storage time, T off_DCM This is the second continuous flow time.

[0131] Please continue reading. Figure 9 , Figure 9 yes Figure 8 A flowchart illustrating an embodiment of S592 is provided. In one embodiment, the control method for the three-phase conversion circuit of this application, in addition to S591-S593 described above, further includes some more specific steps. Specifically, S592 may further include the following steps: S5921: The first duration, the second duration, and the resonant period are obtained by using the filter inductance value and the output capacitance of the switching transistor.

[0132] Specifically, the first duration, the second duration, and the resonance period are calculated using a preset function based on the filter inductance value and the output capacitance of the switching transistor. Specifically, the first duration, the second duration, and the resonance period can be obtained by setting the filter inductance value and the output capacitance of the switching transistor as independent variables in a simulation experiment, continuously adjusting these independent variables to obtain corresponding simulation experimental data, or by obtaining statistical data from actual application scenarios. The simulation experimental data and / or statistical data are then analyzed and fitted to obtain the first duration, the second duration, and the resonance period, or a corresponding preset function is used to calculate the first duration, the second duration, and the resonance period. This application does not limit the scope of this method.

[0133] S5922: The total resonant time is obtained by using the third adjustment function to calculate and process the first switching cycle, the second dead time, the initial freewheeling time, the initial energy storage time, the first duration, the second duration, and the resonant period.

[0134] The calculation formula for the third adjustment function is as follows: ; ; Among them, T LC For the resonant period, T TCM For the first switching cycle, T delay2 The second dead time, T1 is the first duration, T2 is the second duration, x is the number of resonant periods, and T... wait This is the total resonance time.

[0135] S5923: The second compensation coefficient is obtained using the total resonance time and the second dead time.

[0136] Furthermore, a second compensation coefficient is obtained by calculating the total resonance time and the second dead time using a preset function. Specifically, this can be achieved by setting the total resonance time and the second dead time as independent variables in a simulation experiment, continuously adjusting these independent variables to obtain corresponding simulation experimental data, or by obtaining statistical data from actual application scenarios, and then analyzing and fitting the simulation experimental data and / or statistical data to obtain the second compensation coefficient, or by using a corresponding preset function to calculate the second compensation coefficient; or by being determined by the power and control loop, which is not limited in this application.

[0137] Please continue reading. Figure 10 , Figure 10 yes Figure 4 A flowchart illustrating the first embodiment of S510 is shown. In one embodiment, the control method for the three-phase conversion circuit of this application, in addition to the above-described S51-S511, further includes some more specific steps. Specifically, the above-described S510 may further include the following steps: S51011: At the beginning of the second switching cycle of each second control signal, the third drive signal is adjusted to the first level state.

[0138] Specifically, the second control signal further includes a third drive signal PWM3 and a fourth drive signal PWM4; when the third switch S3 is an energy storage tube and the fourth switch S4 is a freewheeling tube, the third drive signal PWM3 and the fourth drive signal PWM4 correspond to the drive control signals of the third switch S3 and the fourth switch S4, respectively; while when the fourth switch S4 is an energy storage tube and the third switch S3 is a freewheeling tube, the third drive signal PWM3 and the fourth drive signal PWM4 correspond to the drive control signals of the fourth switch S4 and the third switch S3, respectively.

[0139] Similarly, when the fifth switch S5 is an energy storage transistor and the sixth switch S6 is a freewheeling transistor, the other third drive signal PWM3 and the other fourth drive signal PWM4 correspond to the drive control signals of the fifth switch S5 and the sixth switch S6, respectively; while when the sixth switch S6 is an energy storage transistor and the fifth switch S5 is a freewheeling transistor, the other third drive signal PWM3 and the other fourth drive signal PWM4 correspond to the drive control signals of the sixth switch S6 and the fifth switch S5, respectively.

[0140] Understandably, such as Figure 6 As shown in (b), after obtaining the second energy storage time T on_DCM Second continuous current time T off_DCM Second dead zone time T delay2 Second switching cycle T DCM Subsequently, in each second switching cycle T of each second control signal DCMAt the start time, i.e., time t0, the third drive signal PWM3 is adjusted to the first level state.

[0141] S51012: After the second energy storage time, adjust the third drive signal from the first level state to the second level state.

[0142] Second energy storage time T on_DCM Then, at time t1, the third drive signal PWM3 is adjusted from the first level state to the second level state.

[0143] S51013: After delaying the second dead time, adjust the fourth drive signal from the second level state to the first level state.

[0144] Delay the second dead zone time T delay2 Then, after time t2, and after another turn-on delay, the fourth drive signal PWM4 is adjusted from the second level state to the first level state.

[0145] S51014: After the second freewheeling time, adjust the fourth drive signal from the first level state to the second level state.

[0146] Second continuous flow time T on_DCM Then, at time t3, the fourth drive signal PWM4 is adjusted from the first level state to the second level state.

[0147] Understandably, the principle of discontinuous current control is as follows: using the second inductor current i during the same period... L2 Taking a value less than 0 as an example, the third switch S3 is an energy storage transistor, and the fourth switch S4 is a freewheeling transistor. During the time period t0-t1, the third switch S3 is turned on, and the fourth switch S4 is turned off, and the second inductor current i... L2 The current increases linearly, the third switch S3 is turned off at time t1, and the second inductor current i L2 The peak value is reached; the second dead time is the period t1-t2, during which the third switch S3 and the fourth switch S4 are both turned off, and then the parallel filter capacitors of the third switch S3 and the fourth switch S4 are charged and discharged respectively. After a brief resonance process, the output capacitor of the fourth switch S4 is completely discharged to 0V, and the body diode of the fourth switch S4 is turned on at time t2.

[0148] If the fourth switch S4 is turned on after t2, ZVS of the fourth switch S4 can be achieved; during the t2-t3 period, the third switch S3 is turned off and the fourth switch S4 is turned on, at which time the second inductor current i L2 The current begins to decrease, and at time t3, the fourth switch S4 is turned off, and the second inductor current i... L2The current is reduced to 0A to achieve ZCS turn-off; then, during the t3-t7 period, the filter inductor resonates with the output capacitors of the two switching transistors. In order to minimize the turn-on loss of the third switching transistor S3 in DCM mode, the third switching transistor S3 should be at its second energy storage tube drain-source voltage V dS3 The circuit resonates until it turns on at the xth valley (x is an integer), thereby achieving valley voltage turn-on or ZVS for the third switch S3. In particular, the value of x is determined by the switching frequency of the phase with the largest absolute value of input current / input voltage at the current moment.

[0149] Please continue reading. Figure 11 , Figure 11 yes Figure 5 A waveform diagram of the relevant signals in the three-phase converter circuit in the second embodiment.

[0150] Understandably, Figure 11 The diagram shows the trend of the switching frequency fs under the power frequency cycle. The switching frequency fs trends of the current discontinuous control phase and the delta current control phase are consistent and have the same range of variation, so they will not be described in detail here.

[0151] Furthermore, in some embodiments, after S51014 above, the method further includes: during the total resonance time T wait Then, it enters the next second switching cycle T. DCM The third drive signal PWM3 is adjusted from the second level state to the first level state.

[0152] Understandably, at time t3, the fourth drive signal PWM4 is adjusted from the first level state to the second level state, and the current second switching cycle T... DCM It doesn't actually end there; specifically, it continues after the total resonance time T. wait Then, the next second switching cycle T begins. DCM The third drive signal PWM3 is adjusted from the second level state to the first level state.

[0153] Furthermore, in some embodiments, the above-mentioned S51014 can be replaced by: responding to the second inductor current i in each current discontinuity control phase. L2 When the signal crosses zero, the fourth drive signal PWM4 is adjusted from the first level state to the second level state.

[0154] In other embodiments, the control circuit may further include a zero-crossing detection circuit, which is used to perform zero-crossing detection on the A-phase inductor current iLa, the B-phase inductor current iLb, and the C-phase inductor current iLc, respectively, or on each second inductor current iLc currently determined to be a current discontinuous control phase. L2Zero-crossing detection is performed separately. For example, the A-phase inductor current iLa and the C-phase inductor current iLc in the first sector are respectively zero-crossing detected. After the zero-crossing moment of the A-phase inductor current iLa or the C-phase inductor current iLc is detected, each fourth drive signal PWM4 is adjusted from the first level state to the second level state.

[0155] Furthermore, in some embodiments, the above-mentioned S51014 can be specifically replaced by: responding to the second inductor current i in each current discontinuity control phase. L2 The second (x+1)th zero crossing occurs, marking the start of the next second switching cycle T. DCM The third drive signal PWM3 is adjusted from the second level state to the first level state.

[0156] Furthermore, the zero-crossing detection circuit is also used to detect the second inductor current i in each discontinuous current control phase. L2 After time t3, at the 2*(x+1)th zero crossing, the next second switching cycle T begins. DCM And adjust each third drive signal PWM3 from the second level state to the first level state.

[0157] Please continue reading. Figure 12 , Figure 12 yes Figure 4 A flowchart illustrating the second embodiment of S510 is shown. In one embodiment, the control method for the three-phase conversion circuit of this application, in addition to the above-described S51-S511, further includes some more specific steps. Specifically, the above-described S510 may further include the following steps: S51021: At the beginning of the second switching cycle of each second control signal, the third drive signal is adjusted to the first level state.

[0158] S51022: After the second energy storage time, adjust the third drive signal from the first level state to the second level state.

[0159] Among them, S51021 and S51022 and Figure 10 S51011 and S51012 are the same. For details, please refer to S1911 and S1912 and their related textual descriptions, which will not be repeated here.

[0160] S51023: Detect whether the load rate of the three-phase conversion circuit is lower than the preset load threshold.

[0161] Please continue reading. Figure 13 , Figure 13 yes Figure 5 A waveform diagram of the relevant signals in the three-phase converter circuit in the third embodiment.

[0162] Understandably, under light no-load conditions or near the zero crossing of the second input current Iavg_D under heavy load, in order to ensure conversion efficiency and better meet the power supply requirements in this special scenario, the fourth drive signal PWM4 also needs to be adjusted.

[0163] Specifically, the current load rate of the three-phase conversion circuit 30, i.e., the ratio of the actual load power to the rated load power, is detected to determine whether the current load rate is lower than the preset load threshold.

[0164] It is worth noting that the load capacity of electronic circuits typically includes no-load, light-load, full-load, and overload. No-load refers to the operating state of the equipment or system without any connected load; light-load is significantly below the rated capacity, with the specific percentage varying depending on the field, usually referring to a load rate below 30% of the rated power (or defined as below 50% in some scenarios); full-load means the load is close to or equal to the rated capacity, such as when the generator's output power matches the nameplate value; overload means the load exceeds the rated capacity.

[0165] In addition, the load factor is a core parameter that measures the relationship between the actual operating load of equipment or system and its rated capacity. Its definition and calculation method vary depending on the application field.

[0166] General definition: Load factor = Actual load / Rated load * 100%, applicable to scenarios such as transformers, motors, and power systems. For example: The load factor of a transformer is the ratio of the output apparent power to the rated capacity.

[0167] In some embodiments, the preset load threshold may specifically correspond to the load rate under light load conditions, such as any reasonable proportional threshold such as 30%, 50% or 60%, and this application does not limit it.

[0168] If the load rate of the three-phase conversion circuit 30 is lower than the preset load threshold, then S51024 is executed; if the load rate of the three-phase conversion circuit 30 is not lower than the preset load threshold, then S51026 is executed.

[0169] S51024: After delaying the sum of the second dead time, the second freewheeling time, the first duration, the second duration, and the cumulative duration of (x-1)*resonance period, the fourth drive signal is adjusted from the second level state to the first level state.

[0170] When it is determined that the current load rate of the three-phase converter circuit 30 is lower than the preset load threshold, the second dead time T is delayed. delay2 Second continuous current time T off_DCM The first duration T1, the second duration T2, and the (x-1)*resonance period T LC After the cumulative duration is summed, the fourth drive signal PWM4 is adjusted from the second level state to the first level state.

[0171] S51025: After a second set duration, adjust the fourth drive signal from the first level state to the second level state.

[0172] After a second set time period, the fourth drive signal PWM4 is adjusted from the first level state to the second level state.

[0173] Understandably, under light no-load conditions or heavy load conditions, the second input current I... avg_D Near the zero crossing, after the energy storage tube, i.e., the third switch S3, is turned off, the freewheeling tube, i.e., the fourth switch S4, remains off, meaning the second inductor current i... L2 The current flows to the body diode of the fourth switch S4 until the drain-source voltage V of the third switch S3 is reached. dS3 When the resonance reaches the last peak, the fourth switch S4 is turned on for a period of time. At this time, the switching frequency of the discontinuous current control phase will be the same as that of the delta current control phase. The third switch S3 of the discontinuous current control phase can achieve ZVS turn-on to further improve the light no-load efficiency.

[0174] S51026: After delaying the second dead time, adjust the fourth drive signal from the second level state to the first level state.

[0175] S51027: After the second freewheeling time, adjust the fourth drive signal from the first level state to the second level state.

[0176] Among them, S51026 and S51027 and Figure 10 S51013 and S51014 are the same. Please refer to S51013 and S51014 and their related textual descriptions for details, which will not be repeated here.

[0177] Please continue reading. Figure 14 , Figure 14 yes Figure 4 A flowchart illustrating the third embodiment of S510 is shown. In one embodiment, the control method for the three-phase conversion circuit of this application, in addition to the above-described S51-S511, further includes some more specific steps. Specifically, the above-described S510 may further include the following steps: S51031: At the beginning of the second switching cycle of each second control signal, the third drive signal is adjusted to the first level state.

[0178] S51032: After the second energy storage time, adjust the third drive signal from the first level state to the second level state.

[0179] Among them, S51031 and S51032 and Figure 12S51021 and S51022 are the same. Please refer to S51021 and S51022 and their related textual descriptions for details, which will not be repeated here.

[0180] S51033: Detect whether the second input current is within the preset threshold range.

[0181] Similarly, to increase the second input current I under heavy load avg_D To improve the conversion efficiency near zero and better meet the power supply requirements in this special scenario, the fourth drive signal PWM4 also needs to be adjusted.

[0182] Specifically, the second input current I, obtained through function calculation, is detected. avg_D Whether it is within the preset threshold range.

[0183] It is understood that the preset threshold range is specifically a current threshold range with zero current as the intermediate value, which is obtained by fitting simulation experimental data in actual application scenarios, and this application does not limit it.

[0184] Wherein, if the second input current I avg_D If the current is within the preset threshold range, then execute S51034. If the second input current I... avg_D If the value is not within the preset threshold range, then execute S51036.

[0185] S51034: After delaying the sum of the second dead time, the second freewheeling time, the first duration, the second duration, and the cumulative duration of (x-1)*resonance period, the fourth drive signal is adjusted from the second level state to the first level state.

[0186] S51035: After a second set duration, adjust the fourth drive signal from the first level state to the second level state.

[0187] S51036: After a second dead time delay, adjust the fourth drive signal from the second level state to the first level state.

[0188] S51037: After the second freewheeling time, adjust the fourth drive signal from the first level state to the second level state.

[0189] Among them, S51024, S51025, S51026 and S51027 and Figure 12 The same applies to S51034, S51035, S51026 and S51027. For details, please refer to the textual descriptions of S51034, S51035, S51026 and S51027 and their related texts. They will not be repeated here.

[0190] Please see Figure 15 , Figure 15This is a flowchart illustrating the third embodiment of the control method for the three-phase converter circuit of this application. The control method for the three-phase converter circuit in this embodiment... Figure 1 A detailed implementation diagram of the control method for the three-phase converter circuit is shown, which specifically includes the following steps: S61: Obtain the A-phase input voltage, B-phase input voltage, and C-phase input voltage of the three-phase converter circuit.

[0191] S62: Determine one phase of the three-phase converter circuit corresponding to the one with the largest absolute value of the amplitude among the input voltages of phase A, phase B, and phase C as the triangular current control phase.

[0192] S63: Determine the other two phases in the three-phase conversion circuit as current discontinuous control phases.

[0193] S64: Obtain the first characteristic parameter of the triangular current control phase and the second characteristic parameter of each current discontinuous control phase.

[0194] S65: The first energy storage time and the first freewheeling time are obtained using the first energy storage inductor voltage and the first freewheeling inductor voltage.

[0195] S66: The first switching cycle is obtained by utilizing the first energy storage time and the first freewheeling time.

[0196] Among them, S61, S62, S63, S64, S65 and S66 and Figure 1 S11, S12, S13, S14, S15 and S16 are the same. For details, please refer to the textual descriptions of S11, S12, S13, S14, S15 and S16 and their related texts. They will not be repeated here.

[0197] S67: Detect whether the first switching cycle is less than the minimum set cycle.

[0198] Understandably, voltage sampling or other anomalies in the three-phase converter circuit 30 may lead to soft-switching condition mismatch, significantly increasing the difficulty of maintaining zero-voltage turn-on and / or valley-voltage turn-on under load surges or asymmetrical operating conditions. Furthermore, an excessively wide range of switching frequency variations will also cause current distortion and other problems. Therefore, it is necessary to ensure that the switching frequency of the DCM phase differs from the switching frequency of the TCM phase at the same time by one resonant frequency. In this case, the switching frequency range of each sector will be naturally limited to a smaller range.

[0199] Specifically, it detects and determines whether the currently acquired first switching cycle is less than the minimum set cycle.

[0200] It is worth noting that the minimum set period can actually be understood as the maximum set frequency, and it can be specifically set based on simulation experimental data that can limit the switching frequencies of the two DCM phases to within one resonant frequency of the switching frequency of the TCM phase at the same time. This application does not limit this.

[0201] If the first switching period is less than the minimum set period, then S18 is executed; if the first switching period is not less than the minimum set period, then S111 is executed.

[0202] S68: Generate a first control signal using the minimum set period, the first energy storage time, and the first freewheeling time.

[0203] It is understandable that the first energy storage time and the first freewheeling time correspond to the duration of the energy storage tube and the freewheeling tube in the triangular current control phase being triggered to conduct, respectively. They can also be understood as the turn-on time and the turn-off time, respectively, and correspond to the duration of the high and low levels of the first control signal.

[0204] Under normal circumstances, without considering the dead time, the end time of the first freewheeling time is the end time of the first switching cycle and corresponds to the start time of the next first switching cycle. However, in order to ensure that the switching frequencies of the two current discontinuous control phases and the switching frequencies of the triangular current control phase at the same time are both limited to a resonant frequency difference, when it is determined that the currently acquired first switching cycle is less than the minimum set cycle, after the end time of the first freewheeling time, it is necessary to extend the time for a period of time so that the current actual switching cycle is the minimum set cycle before entering the next first switching cycle or the minimum set cycle. At this time, the triangular current control phase has actually become a current discontinuous control phase after the period extension, that is, all three phases actually adopt the DCM control strategy to achieve the corresponding control.

[0205] Specifically, when it is determined that the currently acquired first switching period is less than the minimum set period, the level state is adjusted in response to the currently acquired first energy storage time and first freewheeling time, and the first switching period is extended to the minimum set period to generate a first control signal.

[0206] S69: The corresponding limited on-time and limited off-time are obtained by using the minimum setting period and each second characteristic parameter.

[0207] The minimum set period and each second characteristic parameter are processed by a preset control program or adjustment function to obtain the limited turn-on time and limited turn-off time corresponding to each current discontinuous control.

[0208] S610: Generate a second control signal using each corresponding limited on-time and limited off-time.

[0209] The level state is adjusted in response to the limited on-time and limited off-time corresponding to each current discontinuous control acquired at the moment, so as to generate a second control signal.

[0210] It is worth noting that the limited turn-on time and limited turn-off time correspond to the duration of the energy storage tube and freewheeling tube in each current discontinuous control phase being triggered to conduct, and respectively correspond to the duration of the high and low levels of the second control signal.

[0211] The limited turn-on time, limited turn-off time, and corresponding second control signal for different current discontinuous control phases are actually different, but the corresponding calculation formulas and control programs are the same, so they are not distinguished in name.

[0212] S611: Generate a first control signal using the first energy storage time and the first freewheeling time.

[0213] When it is determined that the currently acquired first switching period is not less than the minimum set period, the level state is adjusted in response to the currently acquired first energy storage time and first freewheeling time to generate a first control signal. At this time, the first switching period does not need to be extended, that is, the actual switching period of the first control signal is equal to the currently acquired first switching period.

[0214] S612: The second energy storage time and the second freewheeling time are obtained by using the first switching cycle and each second characteristic parameter.

[0215] A preset control program or adjustment function is used to process the first switching cycle and each second characteristic parameter to obtain the second energy storage time and the second freewheeling time corresponding to each current discontinuous control.

[0216] S613: Generate a second control signal using each corresponding second energy storage time and second freewheeling time.

[0217] In response to each current discontinuous control, the level state is adjusted according to the corresponding second energy storage time and second freewheeling time to generate a second control signal.

[0218] S614: Send the first control signal and each of the second control signals to the delta current control phase and each of the current discontinuous control phases respectively, so as to trigger the delta current control phase and each of the current discontinuous control phases to change the switching state respectively.

[0219] The first control signal is sent to the delta current control phase, and at the same time, each second control signal is sent to the two current discontinuous control phases respectively, so as to trigger the relevant switching elements inside the delta current control phase and each current discontinuous control phase to change the switching state, thereby adjusting the output voltage and / or output current of the three-phase conversion circuit 30.

[0220] For example, when the B-phase switch sub-circuit is a delta current control phase, and the A-phase switch sub-circuit and the C-phase switch sub-circuit are both current discontinuous control phases, the currently generated first control signal is sent to the B-phase switch sub-circuit, and each second control signal is sent to the A-phase switch sub-circuit and the C-phase switch sub-circuit respectively, so as to trigger the relevant internal switching elements to change the switching state, thereby adjusting the output voltage and / or output current of the three-phase conversion circuit 30.

[0221] It is worth noting that the signal frequency of the A-phase input voltage Ua is much lower than the signal frequencies of the first control signal and each of the second control signals. Within a complete sine wave cycle with the A-phase input voltage Ua as the reference, there will be multiple cycle stages where the absolute values ​​of the amplitudes of the A-phase input voltage Ua, B-phase input voltage Ub, and C-phase input voltage Uc have different magnitude orders. These different magnitude orders will correspond to different relationships between the A-phase switch sub-circuit, B-phase switch sub-circuit, and C-phase switch sub-circuit and the delta current control phase and the current discontinuous control phase, respectively. In each cycle stage, the first control signal and each of the second control signals are continuously sent to the delta current control phase and the current discontinuous control phase according to the currently determined relationship, until the relationship changes and the next cycle stage begins. The transmission mode of the control signals of each phase switch sub-circuit is then readjusted, which will not be elaborated further here.

[0222] This application also provides an electronic device, please refer to... Figure 16 , Figure 16 This is a schematic diagram of one embodiment of the electronic device of this application. In this embodiment, the electronic device 70 includes a housing 71 and a control circuit 72 connected to the housing 71.

[0223] It should be noted that the control circuit 72 described in this embodiment is the control circuit 20 or control circuit described in any of the above embodiments. Please refer to [link / reference] for details. Figures 1-15 The relevant textual content will not be elaborated upon here.

[0224] The beneficial effects of this application are as follows: Unlike the prior art, the control method of the three-phase converter circuit provided in this application determines one phase of the three-phase converter circuit with the largest absolute value of the amplitude among the input voltages of phase A, phase B, and phase C as the delta current control phase, and determines the other two phases as the discontinuous current control phase. The first energy storage time, the first freewheeling time, and the first switching cycle are obtained using the first energy storage inductor voltage and the first freewheeling inductor voltage of the delta current control phase, so as to generate a first control signal for controlling the delta current control phase. The second energy storage time and the second freewheeling time are obtained using the first switching cycle and each second characteristic parameter, respectively, so as to generate a second control signal for controlling the discontinuous current control phase. This allows the three-phase converter circuit to operate in delta current mode or discontinuous current mode in a time-division manner. The switching frequency of the discontinuous current mode at each moment is within one resonant frequency of the switching frequency of the delta current mode, which naturally reduces the switching frequency range and eliminates the need for additional components. This makes it easier to realize zero-voltage turn-on and / or valley voltage turn-on of the three-phase converter circuit, thereby improving efficiency and reducing costs.

[0225] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A control method for a three-phase conversion circuit, characterized in that, The control method for the three-phase conversion circuit includes: Obtain the A-phase input voltage, B-phase input voltage, and C-phase input voltage of the three-phase converter circuit; The phase of the three-phase converter circuit corresponding to the one with the largest absolute value of the amplitude among the input voltage of phase A, phase B, and phase C is determined as the triangular current control phase; The other two phases in the three-phase conversion circuit are designated as current discontinuity control phases; Obtain the first characteristic parameter of the triangular current control phase and the second characteristic parameter of each current discontinuous control phase; wherein, the first characteristic parameter includes the first energy storage inductor voltage and the first freewheeling inductor voltage; The first energy storage time and the first freewheeling time are obtained using the first energy storage inductor voltage and the first freewheeling inductor voltage. The first switching cycle is obtained using the first energy storage time and the first freewheeling time; A first control signal is generated using the first energy storage time and the first freewheeling time; The second energy storage time and the second freewheeling time are obtained by using the first switching cycle and each of the second characteristic parameters, respectively. A second control signal is generated using each corresponding second energy storage time and second freewheeling time; The first control signal and each of the second control signals are respectively sent to the triangular current control phase and each of the current discontinuity control phases to trigger the triangular current control phase and each of the current discontinuity control phases to change their switching states.

2. The control method for the three-phase conversion circuit according to claim 1, characterized in that, The first characteristic parameters further include a first input voltage, a first output reference voltage, a second output reference voltage, a first filter capacitor voltage, a first input current, and a filter inductance value. Before the step of obtaining the first energy storage time and the first freewheeling time using the first energy storage inductor voltage and the first freewheeling inductor voltage, the method further includes: The first energy storage inductor voltage and the first freewheeling inductor voltage are obtained using the first input voltage, the first output reference voltage, the second output reference voltage, and the first filter capacitor voltage. The step of obtaining the first energy storage time and the first freewheeling time using the first energy storage inductor voltage and the first freewheeling inductor voltage includes: The first energy storage time and the first freewheeling time are obtained using the first energy storage inductor voltage, the first freewheeling inductor voltage, the first input current, and the value of the filter inductor.

3. The control method for the three-phase conversion circuit according to claim 2, characterized in that, The first characteristic parameter further includes input power, first input voltage, and effective value of input phase voltage. Before the step of obtaining the first energy storage time and first freewheeling time using the first energy storage inductor voltage, first freewheeling inductor voltage, first input current, and the filter inductor value, the method further includes: The first input current is obtained using the input power, the first input voltage, and the effective value of the input phase voltage.

4. The control method for the three-phase conversion circuit according to claim 2, characterized in that, The first characteristic parameter further includes setting a negative current. The step of obtaining the first energy storage time and the first freewheeling time using the first energy storage inductor voltage, the first freewheeling inductor voltage, the first input current, and the filter inductor value includes: The first energy storage time and the first freewheeling time are obtained by performing calculations on the first energy storage inductor voltage, the first freewheeling inductor voltage, the first input current, the filter inductor value, and the set negative current using a first adjustment function. The calculation formula for the first adjustment function is as follows: Among them, T on_TCM For the first energy storage time, T off_TCM For the first continuous flow time, I avg_T For the first input current, I R Let L be the set negative current, and U be the value of the filter inductance. Lon_T U is the voltage of the first energy storage inductor. LoffT The voltage of the first freewheeling inductor is denoted as .

5. The control method for the three-phase conversion circuit according to claim 1, characterized in that, The first control signal includes a first drive signal and a second drive signal. The step of generating the first control signal using the first energy storage time and the first freewheeling time includes: At the beginning of the first switching cycle, the first drive signal is adjusted to a first level state; After the first energy storage time, the first drive signal is adjusted from the first level state to the second level state; After a first dead time delay, the second drive signal is adjusted from the second level state to the first level state; After the first freewheeling time, the second drive signal is adjusted from the first level state to the second level state; or, in response to the first inductor current in the triangular current control phase crossing zero, the second drive signal is adjusted from the first level state to the second level state after a first set time delay.

6. The control method for the three-phase conversion circuit according to claim 1, characterized in that, The second characteristic parameters include the second input current, the filter inductor value, the second energy storage inductor voltage, and the second freewheeling inductor voltage. The step of obtaining the corresponding second energy storage time and second freewheeling time using the first switching cycle and each of the second characteristic parameters includes: The second energy storage time and the second freewheeling time are obtained using the first switching cycle, the second input current, the filter inductor value, the second energy storage inductor voltage, and the second freewheeling inductor voltage, respectively.

7. The control method for the three-phase conversion circuit according to claim 6, characterized in that, The second characteristic parameter also includes the second dead time and the output capacitance of the switching transistor. The steps of obtaining the second energy storage time and the second freewheeling time using the first switching cycle, the second input current, the filter inductor value, the second energy storage inductor voltage, and the second freewheeling inductor voltage respectively include: The first compensation coefficient is obtained using the first switching cycle and the value of the filter inductance; The second compensation coefficient is obtained by using the first switching cycle, the second dead time, the filter inductance value, and the output capacitance of the switching transistor; The second adjustment function is used to calculate and process the second input current, the filter inductor value, the second energy storage inductor voltage, the second freewheeling inductor voltage, the first compensation coefficient, and the second compensation coefficient to obtain the corresponding second energy storage time and the second freewheeling time. The calculation formula for the second adjustment function is as follows: Among them, I avg_D The second input current is L, the filter inductance is m, and the first compensation coefficient is U. Lon_D U is the voltage of the second energy storage inductor. Loff_D T is the voltage of the second freewheeling inductor. on_DCM1 For the initial energy storage time, T off_DCM1 T is the initial freewheeling time, k is the second compensation coefficient, and T is the initial freewheeling time. on_DCM For the second energy storage time, T off_DCM This is the second continuous flow time.

8. The control method for the three-phase conversion circuit according to claim 7, characterized in that, The step of obtaining the second compensation coefficient using the first switching cycle, the second dead time, the filter inductance value, and the output capacitance of the switching transistor includes: The first duration, the second duration, and the resonant period are obtained using the filter inductance value and the output capacitance of the switching transistor. The total resonance time is obtained by performing calculations on the first switching cycle, the second dead time, the initial freewheeling time, the initial energy storage time, the first duration, the second duration, and the resonance cycle using a third adjustment function. The second compensation coefficient is obtained using the total resonance time and the second dead time; The calculation formula for the third adjustment function is as follows: T wait =T1+T2+x·T LC ; Among them, T LC For the resonance period, T TCM For the first switching cycle, T delay2 T1 is the second dead time, T2 is the first duration, T2 is the second duration, x is the number of resonant periods, and T is the second dead time. wait The total resonance time is given.

9. The control method for the three-phase conversion circuit according to claim 8, characterized in that, The second control signal includes a third drive signal and a fourth drive signal. The step of generating the second control signal using each corresponding second energy storage time and second freewheeling time includes: At the beginning of the second switching cycle of each of the second control signals, the third drive signal is adjusted to the first level state; After the second energy storage time, the third drive signal is adjusted from the first level state to the second level state; After a second dead time delay, the fourth drive signal is adjusted from the second level state to the first level state; After the second freewheeling time, the fourth drive signal is adjusted from the first level state to the second level state; or, in response to the second inductor current in each of the current discontinuity control phases crossing zero, the fourth drive signal is adjusted from the first level state to the second level state.

10. The control method for the three-phase conversion circuit according to claim 9, characterized in that, After the step of adjusting the fourth drive signal from the first level state to the second level state after the second freewheeling time, the method further includes: After the total resonance time, the next second switching cycle begins, and the third driving signal is adjusted from the second level state to the first level state.

11. The control method for the three-phase conversion circuit according to claim 9, characterized in that, After the step of adjusting the fourth drive signal from the first level state to the second level state after delaying for a second set time in response to the second inductor current crossing zero in each of the current discontinuous control phases, the method further includes: In response to the second inductor current in each of the current discontinuous control phase crossing zero for the 2*(x+1)th time, the third drive signal is adjusted from the second level state to the first level state in the next second switching cycle.

12. The control method for the three-phase conversion circuit according to claim 9, characterized in that, Before the step of adjusting the fourth drive signal from the second level state to the first level state after delaying the second dead time, the method further includes: Detect whether the load rate of the three-phase conversion circuit is lower than a preset load threshold; If the load rate is lower than the preset load threshold, after delaying the sum of the second dead time, the second freewheeling time, the first duration, the second duration, and (x-1)*the cumulative duration of the resonant period, the fourth drive signal is adjusted from the second level state to the first level state. After a second set time period, the fourth driving signal is adjusted from the first level state to the second level state.

13. The control method for the three-phase conversion circuit according to claim 9, characterized in that, Before the step of adjusting the fourth drive signal from the second level state to the first level state after delaying the second dead time, the method further includes: Detect whether the second input current is within a preset threshold range; If the second input current is within a preset threshold range, after delaying the sum of the second dead time, the second freewheeling time, the first duration, the second duration, and (x-1)*the cumulative duration of the resonance period, the fourth driving signal is adjusted from the second level state to the first level state. After a second set time period, the fourth driving signal is adjusted from the first level state to the second level state.

14. The control method for a three-phase converter circuit according to any one of claims 1-13, characterized in that, After the step of obtaining the first switching cycle using the first energy storage time and the first freewheeling time, and before the step of generating the first control signal using the first energy storage time and the first freewheeling time, the method further includes: Detect whether the first switching cycle is less than the minimum set cycle; If the first switching cycle is less than the minimum set cycle, the first control signal is generated using the minimum set cycle, the first energy storage time, and the first freewheeling time. The corresponding limited activation time and limited deactivation time are obtained by using the minimum setting period and each of the second feature parameters; The second control signal is generated using each corresponding defined on-time and defined off-time.

15. A control circuit, characterized in that, The control circuit is used to couple with the three-phase conversion circuit; The control circuit uses the control method for the three-phase conversion circuit as described in any one of claims 1-14 to control the three-phase conversion circuit.

16. An electronic device, characterized in that, The electronic device includes a housing and a control circuit connected to the housing; The control circuit is the control circuit as described in claim 15.

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