Three-phase resonant conversion circuit, control method thereof and electronic equipment

Abstract

The invention discloses a three-phase resonant conversion circuit, a control method thereof and electronic equipment. The control method of the three-phase resonant conversion circuit comprises the following steps: acquiring an output current and / or an output voltage of a three-phase resonant output circuit; generating a three-phase driving control signal or a two-phase driving control signal based on a first comparison result between the output current and the two-phase maximum output current and / or a second comparison result between the output voltage and the two-phase maximum output voltage; and adjusting the switching state of the three-phase switching circuit by using the three-phase driving control signal or the two-phase driving control signal so as to adjust the output voltage or the output current. By means of the mode, the control method of the three-phase resonant conversion circuit responds to the change of the output current and / or the output voltage to achieve flexible switching between the two-phase wave sending mode and the three-phase wave sending mode, so that the efficiency during light load and no load and the stability of the output voltage and the direct-current gain curve state of the output voltage are guaranteed; and the advantage of three-phase interleaved parallel connection when heavy load is taken into account or high output power is needed is considered.

Description

Technical Field

[0001] The present application relates to the field of circuit control technology, and in particular to a three-phase resonant conversion circuit and a control method thereof, and an electronic device. Background Art

[0002] The three-phase LLC (containing an additional inductance (L) in series with the other two components, the inductor L and the capacitor (C), hence the name LLC converter) resonant converter has significant advantages in reducing output current ripple and expanding output power capacity.

[0003] However, at light load and no-load conditions, a higher switching frequency in the three-phase LLC resonant converter is not conducive to improving efficiency. In addition, at light load, the discharge process of the parasitic capacitor after being charged has a particularly large impact on the output of the resonant converter, which will change the state of the DC gain curve and cause the output voltage to be out of control. Summary of the invention

[0004] The main technical problem solved by the present application is to provide a three-phase resonant conversion circuit and a control method and electronic device thereof, which can solve the problem that the three-phase LLC resonant converter in the prior art is not conducive to improving the efficiency when lightly loaded and no-loaded, and when lightly loaded, it will change the state of the DC gain curve, resulting in the output voltage being out of control.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a control method for a three-phase resonant conversion circuit, the three-phase resonant conversion circuit includes a three-phase switching circuit and a three-phase resonant output circuit, the three-phase switching circuit is coupled to the three-phase resonant output circuit, and is used to couple with a power supply circuit, wherein the control method of the three-phase resonant conversion circuit includes: obtaining the output current and / or output voltage of the three-phase resonant output circuit; generating a three-phase drive control signal or a two-phase drive control signal based on a first comparison result between the output current and the maximum output current of the two phases and / or a second comparison result between the output voltage and the maximum output voltage of the two phases; and adjusting the switching state of the three-phase switching circuit using the three-phase drive control signal or the two-phase drive control signal to adjust the output voltage or the output current.

[0006] The step of generating a three-phase drive control signal or a two-phase drive control signal based on a first comparison result between the output current and the two-phase maximum operating voltage and / or a second comparison result between the output voltage and the two-phase maximum output voltage comprises: detecting whether the output current is greater than the two-phase maximum output current; if the output current is greater than the two-phase maximum output current, generating a three-phase drive control signal using the output current or the output voltage; wherein the three-phase switch circuit comprises a first-phase switch subcircuit, a second-phase switch subcircuit and a third-phase switch subcircuit coupled to each other, the first-phase switch subcircuit, the second-phase switch subcircuit and the third-phase switch subcircuit coupled to the three-phase harmonic The invention relates to a three-phase switching circuit for outputting a vibration output circuit, and is used to couple with a power supply circuit; the three-phase drive control signal includes a first drive signal, a second drive signal, and a third drive signal; the step of using the three-phase drive control signal or the two-phase drive control signal to adjust the switch state of the three-phase switch circuit to adjust the output voltage or the output current includes: sending the first drive signal, the second drive signal, and the third drive signal to the first phase switch subcircuit, the second phase switch subcircuit, and the third phase switch subcircuit, respectively, to adjust the switch states of the first phase switch subcircuit, the second phase switch subcircuit, and the third phase switch subcircuit, respectively, so as to adjust the output voltage or the output current.

[0007] Among them, the control method of the three-phase resonant conversion circuit also includes: if the output current is not greater than the maximum output current of the two phases, detecting whether the output voltage is greater than the maximum output voltage of the two phases; if the output voltage is not greater than the maximum output voltage of the two phases, detecting whether the frequency of the pre-transmitted drive signal generated by using the output current or the output voltage is greater than the maximum three-phase wave frequency; if the pre-transmitted drive signal frequency is greater than the maximum three-phase wave frequency, using the current output current or output voltage to generate a two-phase drive control signal; wherein the two-phase drive control signal includes a first control signal and a second control signal; the step of using the three-phase drive control signal or the two-phase drive control signal to adjust the switching state of the three-phase switch circuit to adjust the output voltage or the output current includes: sending the first control signal and the second control signal to any two of the first phase switch subcircuit, the second phase switch subcircuit and the third phase switch subcircuit respectively, so as to adjust the switching state of any two of the first phase switch subcircuit, the second phase switch subcircuit and the third phase switch subcircuit respectively, thereby adjusting the output voltage or the output current.

[0008] Among them, the control method of the three-phase resonant conversion circuit also includes: if the pre-transmitted drive signal frequency is not greater than the three-phase maximum wave frequency, detecting whether the pre-transmitted drive signal frequency is less than the two-phase minimum wave frequency; if the pre-transmitted drive signal frequency is less than the two-phase minimum wave frequency, generating a three-phase drive control signal using the current output current or output voltage.

[0009] Among them, the control method of the three-phase resonant conversion circuit also includes: detecting whether a three-phase drive control signal or a two-phase drive control signal is currently generated; if a three-phase drive control signal is currently generated, detecting whether the frequency of the pre-sent drive signal is greater than the three-phase maximum wave frequency; if the pre-sent drive signal frequency is greater than the three-phase maximum wave frequency, using the output current or the output voltage to adjust the pulse width of the three-phase drive control signal.

[0010] Among them, after the step of using the output voltage to adjust the duty cycle of the three-phase drive control signal, it also includes: detecting whether the pulse width of the adjusted three-phase drive control signal is less than the minimum pulse width; if the pulse width of the adjusted three-phase drive control signal is less than the minimum pulse width, the three-phase drive control signal is on-off regulated.

[0011] Among them, the control method of the three-phase resonant conversion circuit also includes: detecting whether a three-phase drive control signal or a two-phase drive control signal is currently generated; if the pre-sent drive signal frequency is not greater than the three-phase maximum wave frequency, using the output current or output voltage to adjust the signal frequency of the three-phase drive control signal.

[0012] Among them, the control method of the three-phase resonant conversion circuit also includes: if a two-phase drive control signal is currently generated, detecting whether the frequency of the pre-transmitted drive signal is greater than the two-phase maximum wave transmission frequency; if the pre-transmitted drive signal frequency is not greater than the two-phase maximum wave transmission frequency, adjusting the phase difference between the first control signal and the second control signal.

[0013] Among them, after the step of adjusting the phase difference between the first control signal and the second control signal, it also includes: detecting whether the adjusted phase difference between the first control signal and the second control signal is less than the minimum phase difference; if the adjusted phase difference between the first control signal and the second control signal is less than the minimum phase difference, the first control signal and the second control signal are adjusted on and off.

[0014] The control method of the three-phase resonant conversion circuit further includes: if the pre-transmitted drive signal frequency is less than the two-phase maximum wave transmission frequency, adjusting the signal frequency of the two-phase drive control signal by using the output current or the output voltage.

[0015] Before the step of detecting whether the output current is greater than the maximum output current of the two phases, the step further includes: detecting whether it is the first time to power on; if it is the first time to power on, generating a two-phase drive control signal using the output current or the output voltage.

[0016] In order to solve the above technical problems, another technical solution adopted in the present application is: to provide a three-phase resonant conversion circuit, wherein the three-phase resonant conversion circuit includes a three-phase switching circuit, a three-phase resonant output circuit and a control circuit, the three-phase switching circuit is coupled to the three-phase resonant output circuit and is used to couple with the power supply circuit, and the control circuit is coupled to the three-phase switching circuit and the three-phase resonant output circuit; wherein the control circuit is used to control the three-phase switching circuit by adopting the control method of the three-phase resonant conversion circuit as described in any of the above items.

[0017] To solve the above technical problems, another technical solution adopted in the present application is: to provide an electronic device, wherein the electronic device includes a shell and a three-phase resonant conversion circuit connected to the shell; wherein the three-phase resonant conversion circuit is the three-phase resonant conversion circuit as described above.

[0018] The beneficial effects of the present application are as follows: Different from the prior art, the control method of the three-phase resonant conversion circuit provided by the present application obtains the output current and / or output voltage of the three-phase resonant output circuit, generates a three-phase drive control signal or a two-phase drive control signal based on a first comparison result between the output current and the two-phase maximum output current and / or a second comparison result between the output voltage and the two-phase maximum output voltage, and uses the three-phase drive control signal or the two-phase drive control signal to adjust the switch state of the three-phase switch circuit to adjust the output voltage or the output current, so that the two-phase wave generation mode and the three-phase wave generation mode can be flexibly switched in response to the changes in the output current and the output voltage, so that when the load is light or no-load, the three-phase switch circuit is controlled to work in a two-phase full-bridge mode, which is equivalent to that only two bridge arms of the three-phase switch circuit are working alternately, so as to realize two-phase wave generation, so as to ensure the stability of the output voltage and its DC gain curve state, which is helpful to improve the efficiency and stability of the three-phase resonant conversion circuit when the load is light; and when the load is heavy or high output power is required, it can also work in a three-phase interleaved parallel mode to fully utilize the advantages of the three-phase interleaved parallel. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 It is a flowchart of a first implementation method of a control method for a three-phase resonant conversion circuit of the present application; Figure 2 It is a structural schematic diagram of a first embodiment of a three-phase resonant output circuit of the present application; Figure 3It is a flow chart of a second implementation method of a control method for a three-phase resonant conversion circuit of the present application; Figure 4 It is a structural schematic diagram of a specific embodiment of the three-phase resonant output circuit of the present application; Figure 5 It is a schematic structural diagram of an embodiment of an electronic device of the present application. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] The terms "first", "second" and "third" in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second" and "third" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. All directional indications (such as up, down, left, right, front, back...) in the implementation mode of this application are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0022] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] The present application is described in detail below with reference to the accompanying drawings and implementation methods.

[0024] Please refer to Figure 1 and Figure 2 ,in, Figure 1 is a flow chart of a first implementation method of a control method for a three-phase resonant conversion circuit of the present application, Figure 2 This is a schematic diagram of the structure of the first embodiment of the three-phase resonant conversion circuit of the present application. Specifically, it may include the following steps: S11: Obtaining the output current and / or output voltage of the three-phase resonant output circuit.

[0025] It is understandable that the control method of the first three-phase resonant conversion circuit 20 in this embodiment is specifically applied to the following example: Figure 2 The first three-phase resonant conversion circuit 20 shown in the figure includes a first three-phase switching circuit 21 and a first three-phase resonant output circuit 22. The first three-phase switching circuit 21 is coupled to the first three-phase resonant output circuit 22 and is used to couple with the power supply circuit 101. The first three-phase resonant output circuit 22 is also used to couple with the signal function circuit; wherein the first control circuit 23 is coupled to the first three-phase switching circuit 21 and the first three-phase resonant output circuit 22, so as to control the first three-phase switching circuit 21 by adopting the control method of the first three-phase resonant conversion circuit 20 described in any one of the items in the present document.

[0026] It is worth noting that the power supply circuit 101 can specifically be a battery with a DC output, a DC voltage regulator, a photovoltaic power supply, an energy storage power supply, or any reasonable DC or AC power supply such as a grid power supply, a photovoltaic power supply, an independent generator, etc., or it can be a power regulation circuit that receives and converts and regulates a battery, a DC voltage regulator, a photovoltaic power supply, an energy storage power supply, a grid power supply, a photovoltaic power supply, an independent generator or other any reasonable upper power supply to obtain a DC or AC power supply output. This embodiment does not limit this.

[0027] The signal function circuit can be understood as a load circuit that uses the power supply output of the first three-phase resonant conversion circuit 20 to operate, and can also be understood as a back-end function circuit of the first three-phase resonant conversion circuit 20, so as to achieve any reasonable signal function.

[0028] In addition, the term "coupled" herein refers to any direct and indirect connection means. Therefore, if the first circuit is described as being coupled to the second circuit, it means that the first circuit can be directly connected to the second circuit through electrical connection or signal connection methods such as wireless transmission, optical transmission, etc., or can be indirectly connected to the second circuit through other circuits or connection means.

[0029] Specifically, the first control circuit 23 is used to sample the first three-phase resonant output circuit 22 to obtain the output current and / or output voltage output to the back-end signal function circuit.

[0030] S12: Generate a three-phase drive control signal or a two-phase drive control signal based on a first comparison result between the output current and the two-phase maximum output current and / or a second comparison result between the output voltage and the two-phase maximum output voltage.

[0031] The first control circuit 23 compares the currently acquired output current with the maximum two-phase output current to obtain a first comparison result, that is, detects whether the currently acquired output current is greater than the two-phase maximum output current, and / or compares the currently acquired output voltage with the two-phase maximum output voltage to obtain a second comparison result, that is, detects whether the currently acquired output voltage is greater than the two-phase maximum output voltage.

[0032] Among them, the first control circuit 23 is also used to determine the current control mode according to the first comparison result and / or the second comparison result, that is, whether to adopt the three-phase wave generation mode or the two-phase wave generation mode. For example, when it is determined that the currently obtained output current is greater than the two-phase maximum output current, the three-phase wave generation mode is adopted; when it is determined that the currently obtained output current is not greater than the two-phase maximum output current, and the currently obtained output voltage is not greater than the two-phase maximum output voltage, the two-phase wave generation mode is adopted, etc., so as to be able to respond to the first comparison result and / or the second comparison result, and / or any other reasonable judgment and adjustment to reasonably select the three-phase wave generation mode or the two-phase wave generation mode, and the present application does not limit this.

[0033] It is worth noting that the two-phase maximum output current can be specifically obtained by measuring the acceptable current ripple on the input side of the first three-phase resonant conversion circuit 20, and reasonably setting and adjusting the measurement result; the two-phase maximum output voltage can be specifically obtained by measuring the voltage required for the normal operation of the first three-phase resonant conversion circuit 20 under light load and the hard switching physical characteristics of each switch tube in the first three-phase switching circuit 21, and reasonably setting and adjusting the measurement result.

[0034] In addition, light load refers to a common load state of electronic circuits. Load states usually include: no load, light load, full load, and overload. Among them, light load is relative to full load, which means that within the load range of the circuit, the load rate is below 30%. Of course, loads below 50% can also be considered light loads, and there is no strict definition. As for whether light load means large load resistance, it is not certain. In the load of constant current source, the load is light when the resistance is small. In the load of constant voltage source, the load is light when the resistance is large. In the electrical industry, light load means that the electrical control component can drag a load of the same power under the condition of rated power, but its output torque is small. For example: the inverter light load application 7.5KW means that the inverter can drag a motor of the same power at rated power. This motor can only be started with light load, and the motor output torque is small.

[0035] Furthermore, the output current and output voltage of the first three-phase resonant output circuit 22 will have different characteristics under each working state of no-load, light-load, full-load and overload.

[0036] Furthermore, the first control circuit 23 uses one or more of any reasonable feedback regulation methods such as a PI controller (proportional integral controller), a voltage loop, a current loop, etc. to process the currently obtained output voltage or output current to obtain a feedback regulation signal, and then uses the feedback regulation signal to generate a three-phase drive control signal or a two-phase drive control signal according to the currently determined three-phase wave transmission mode or two-phase wave transmission mode.

[0037] In some embodiments, the three-phase drive control signal and the two-phase drive control signal can specifically be one or more of any reasonable control signals such as PWM (Pulse Width Modulation) signal or PFM (Pulse Frequency Modulation) signal, and the present application does not limit this.

[0038] S13: Using the three-phase drive control signal or the two-phase drive control signal to adjust the switch state of the three-phase switch circuit to adjust the output voltage or the output current.

[0039] Specifically, the first control circuit 23 sends the currently generated three-phase drive control signal or two-phase drive control signal to the three phases or any two phases of the first three-phase switch circuit 21 to adjust the switching state of the three phases or any two phases of the first three-phase switch circuit 21, thereby adjusting the output voltage or output current to meet the current load requirements.

[0040] The above scheme realizes flexible switching between the two-phase wave generation mode and the three-phase wave generation mode in response to the changes in the output current and the output voltage, so that when the load is light or no-load, the first three-phase switch circuit 21 is controlled to work in the two-phase full-bridge mode. At this time, it is equivalent to that only two bridge arms of the first three-phase switch circuit 21 are working alternately, so as to realize two-phase wave generation, so as to ensure the stability of the output voltage and its DC gain curve state, which is helpful to improve the efficiency and stability of the first three-phase resonant conversion circuit 20 when the load is light; and when the load is heavy or high output power is required, it can also work in the three-phase interleaved parallel mode to fully utilize the advantages of the three-phase interleaved parallel.

[0041] See also Figure 3 and Figure 4 ,in, Figure 3 is a flow chart of a second embodiment of a control method for a three-phase resonant conversion circuit of the present application, Figure 41 is a schematic diagram of a structure of a specific embodiment of the three-phase resonant conversion circuit of the present application. The control method of the three-phase resonant conversion circuit of this embodiment is Figure 1 A flow chart of a detailed implementation of a control method for a three-phase resonant conversion circuit in FIG. 1 specifically includes the following steps: S41: Check whether it is the first time to power on.

[0042] For ease of understanding, Figure 4 As shown, in this embodiment, taking the second three-phase resonant conversion circuit 30 as a three-phase staggered parallel LLC topology circuit as an example, the second three-phase switch circuit 31 further includes a first-phase switch subcircuit 311, a second-phase switch subcircuit 312 and a third-phase switch subcircuit 313 coupled to each other, and the second three-phase switch circuit 31 is used to couple with the power supply circuit 101 to receive the input voltage Vin provided by the power supply circuit 101; the first-phase switch subcircuit 311 includes a first switch tube Q1 and a second switch tube Q2, the second-phase switch subcircuit 312 includes a third switch tube Q3 and a fourth switch tube Q4, and the third-phase switch subcircuit 313 includes a fifth switch tube Q5 and a sixth switch tube Q6.

[0043] Among them, the "three-phase" in this article can be understood as the first-phase switch subcircuit 311, the second-phase switch subcircuit 312 and the third-phase switch subcircuit 313, and the "two-phase" corresponds to any two phases of the first-phase switch subcircuit 311, the second-phase switch subcircuit 312 and the third-phase switch subcircuit 313.

[0044] The second three-phase resonant output circuit 32 may further include a three-phase resonant circuit 321, a three-phase isolation transformer circuit 322, a three-phase rectifier circuit 323 and a voltage-stabilizing output circuit 324. The three-phase resonant circuit 321 includes a first resonant inductor Lr1, a first resonant capacitor Cr1, a second resonant inductor Lr2, a second resonant capacitor Cr2, a third resonant inductor Lr3 and a third resonant capacitor Cr3. The three-phase isolation transformer circuit 322 includes a first primary winding Lm1, a second primary winding Lm2, a third primary winding Lm3, a first secondary winding Ln1, a second secondary winding Ln2 and a third secondary winding Ln3. The three-phase rectifier circuit 323 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6. The voltage-stabilizing output circuit 324 includes a voltage-stabilizing resistor Ro.

[0045] Among them, the second end of the first switch tube Q1 is coupled to the second end of the third switch tube Q3 and the second end of the fifth switch tube Q5, and is used to couple with the first end of the power circuit 101, the third end of the first switch tube Q1 is coupled to the second end of the second switch tube Q2 and the first end of the first resonant inductor Lr1, the third end of the third switch tube Q3 is coupled to the second end of the fourth switch tube Q4 and the first end of the second resonant inductor Lr2, the third end of the fifth switch tube Q5 is coupled to the second end of the sixth switch tube Q6 and the first end of the third resonant inductor Lr3, the third end of the second switch tube Q2 is coupled to the third end of the fourth switch tube Q4 and the third end of the sixth switch tube Q6, and is used to couple with the second end of the power circuit 101, and the first end of each switch tube of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5 and the sixth switch tube Q6 is coupled to the control circuit (not shown in the figure), and has a freewheeling diode and a parasitic capacitor inside.

[0046] The second end of the first resonant inductor Lr1 is coupled to the first end of the first resonant capacitor Cr1, the second end of the second resonant inductor Lr2 is coupled to the first end of the second resonant capacitor Cr2, the second end of the third resonant inductor Lr3 is coupled to the first end of the third resonant capacitor Cr3, the second end of the first resonant capacitor Cr1 is coupled to the first end of the first primary winding Lm1, the second end of the second resonant capacitor Cr2 is coupled to the first end of the second primary winding Lm2, the second end of the third resonant capacitor Cr3 is coupled to the first end of the third primary winding Lm3, the second end of the first primary winding Lm1 is coupled to the second end of the second primary winding Lm2 and the second end of the third primary winding Lm3, the first primary winding Lm1 is coupled to the first secondary winding Ln1, the second primary winding Lm2 is coupled to the second secondary winding Ln2, the third primary winding Lm3 is coupled to the third secondary winding Ln3, the first secondary winding Ln1 is coupled to the second primary winding Lm2, the second primary winding Lm3 is coupled to the third secondary winding Ln3, and the first secondary winding Ln2 is coupled to the second primary winding Lm3. The first end of the group Ln1 is coupled to the first end of the first diode D1 and the second end of the second diode D2, the first end of the second secondary winding Ln2 is coupled to the first end of the third diode D3 and the second end of the fourth diode D4, the first end of the third secondary winding Ln3 is coupled to the first end of the fifth diode D5 and the second end of the sixth diode D6, the second end of the first secondary winding Ln1 is coupled to the second end of the second secondary winding Ln2 and the second end of the second secondary winding Ln2, the second end of the first diode D1 is coupled to the second end of the third diode D3, the second end of the fifth diode D5 and the first end of the zener resistor Ro, and is used to couple with the first end of the signal function circuit, the second end of the first end of the second diode D2 is coupled to the first end of the fourth diode D4, the first end of the sixth diode D6 and the second end of the zener resistor Ro, and is used to couple with the second end of the signal function circuit.

[0047] In other embodiments, the second three-phase resonant output circuit 32 may specifically include a larger number of inductors, and / or resistors, and / or capacitors; each secondary winding in the three-phase isolation transformer circuit 322 may specifically have at least two sub-windings; each diode in the three-phase rectifier circuit 323 may specifically be replaced by a switching tube; the voltage-stabilizing output circuit 324 may specifically include a voltage-stabilizing capacitor, and may also be integrated in the back-end signal function circuit, that is, the second three-phase resonant conversion circuit 30 may specifically be any other reasonable three-phase LLC resonant topology circuit topology form, which is specifically determined by the actual application scenario and is not limited in this application.

[0048] In some embodiments, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5 and the sixth switch tube Q6 can specifically be a MOS (Metal Oxide Semiconductor Field Effect Transistor) tube, a triode, a thin film transistor or a field effect transistor or any other reasonable switch tube, and the present application does not limit this.

[0049] It is worth noting that, in order to distinguish the two ends of each switch tube except the control end, one of them is called the second end and the other is called the third end. When each switch tube is a triode, the control end, that is, the first end, can be specifically the base, the second end is the collector, and the third end is the emitter; or, the first end can also be specifically the base, the second end is the emitter, and the third end is the collector.

[0050] When the above switch tubes are MOS tubes, thin film transistors or field effect transistors, the first end can be a gate, the second end can be a drain, and the third end can be a source; or, the first end can be a gate, the second end can be a source, and the third end can be a drain.

[0051] When each switch tube is a MOS tube, a thin film transistor or a field effect transistor, it can also be a composite transistor or a single transistor, which is not limited in the present application.

[0052] In some embodiments, the control circuit may specifically include a control chip, an MCU (Micro Controller Unit) circuit, a CPU (Central Processing Unit), a single-chip microcomputer, a field programmable gate array, a programmable logic device, a discrete gate or transistor logic device, discrete hardware, and any other reasonable circuit unit with a signal processing function, and the present application does not limit this.

[0053] Specifically, when determining the current control mode, the control circuit first detects whether it is the first time to power on, that is, performs a power-on detection to determine whether it is the first time to enter the control mode.

[0054] If it is the first time to power on, then execute S42; if it is not the first time to power on, then execute S44.

[0055] S42: Obtaining the output current and / or output voltage of the three-phase resonant output circuit.

[0056] Among them, S42 and Figure 1 For details, please refer to S11 and its related text descriptions, which will not be repeated here.

[0057] S43: Generate a two-phase drive control signal using the output current or the output voltage.

[0058] The control circuit enters a two-phase wave generation mode to sample and obtain the output voltage Vo or output current Io of the second three-phase resonant output circuit 32 in real time, thereby generating a two-phase drive control signal by feedback regulation of the output voltage Vo or output current Io.

[0059] It is worth noting that the three-phase drive control signal in this article can be specifically understood as the first drive signal, the second drive signal and the third drive signal sent to the first phase switch sub-circuit 311, the second phase switch sub-circuit 312 and the third phase switch sub-circuit 313 respectively, that is, the three-phase drive control signal specifically includes the first drive signal, the second drive signal and the third drive signal; and under normal circumstances, the phases of each two drive signals of the first drive signal, the second drive signal and the third drive signal differ by 120 degrees from each other; in addition, the phases of the two drive signals corresponding to the two switch tubes in each switch sub-circuit of the first phase switch sub-circuit 311, the second phase switch sub-circuit 312 and the third phase switch sub-circuit 313 differ by 180 degrees from each other.

[0060] In addition, the two-phase drive control signal can be specifically understood as the first control signal and the second control signal respectively sent to any two switch sub-circuits among the first-phase switch sub-circuit 311, the second-phase switch sub-circuit 312 and the third-phase switch sub-circuit 313, that is, the two-phase drive control signal specifically includes the first control signal and the second control signal; under normal circumstances, the phase difference between the first control signal and the second control signal is 180 degrees, and the phase difference between the first control signal and the second control signal can also be adjusted according to control requirements; but the phases of the two control signals corresponding to the two switch tubes in each switch sub-circuit of any two switch sub-circuits among the first-phase switch sub-circuit 311, the second-phase switch sub-circuit 312 and the third-phase switch sub-circuit 313 that respectively receive the first control signal and the second control signal differ by 180 degrees.

[0061] S44: Detect whether the output current is greater than the maximum output current of the two phases.

[0062] Specifically, the control circuit detects whether the output current of the second three-phase resonant output circuit 32 currently sampled and acquired is greater than the two-phase maximum output current.

[0063] If the output current is greater than the maximum output current of the two phases, S45 is executed; if the output current is not greater than the maximum output current of the two phases, S46 is executed.

[0064] S45: Generate a three-phase drive control signal using the output current or the output voltage.

[0065] The control circuit enters a three-phase wave generation mode to generate a three-phase drive control signal by utilizing feedback regulation of the output voltage Vo or the output current Io.

[0066] S46: Check whether the output voltage is greater than the maximum output voltage of the two phases.

[0067] The control circuit detects whether the currently acquired output voltage Vo is greater than the maximum output voltage of the two phases.

[0068] If the output voltage Vo is greater than the maximum output voltage of the two phases, S45 is executed; if the output voltage Vo is not greater than the maximum output voltage of the two phases, S47 is executed.

[0069] S47: Detect whether the frequency of the pre-transmission drive signal generated by the output current or the output voltage is greater than the maximum three-phase transmission frequency.

[0070] The control circuit obtains a feedback regulation signal based on the currently acquired output voltage Vo or output current Io, that is, the output signal given by any reasonable regulation controller such as the corresponding PI controller, speed loop or current loop, and further detects the pre-sent drive signal frequency of the feedback regulation signal, that is, whether the control signal frequency currently required by the second three-phase switching circuit 31 is greater than the three-phase maximum wave transmission frequency.

[0071] It is worth noting that the three-phase maximum wave frequency can be obtained by monitoring and calculating the stress of each switch tube in the second three-phase resonant output circuit 32 and the state of the output DC gain curve, and reasonably setting and adjusting the calculation results.

[0072] If the pre-transmission drive signal frequency is greater than the three-phase maximum wave frequency, S43 is executed; if the pre-transmission drive signal frequency is not greater than the three-phase maximum wave frequency, S48 is executed.

[0073] S48: Detect whether the frequency of the pre-transmitted driving signal is less than the minimum two-phase transmission frequency.

[0074] The control circuit further detects whether the frequency of the pre-transmitted driving signal is less than the minimum two-phase transmission frequency.

[0075] It is worth noting that the two-phase minimum ripple frequency can be obtained by measuring the acceptable current ripple at the input side of the second three-phase resonant output circuit 32 and reasonably setting and adjusting the measurement result.

[0076] S49: Generate a two-phase drive control signal using the output current or the output voltage.

[0077] The control circuit enters a two-phase wave generation mode to sample and obtain the output voltage Vo or output current Io of the second three-phase resonant output circuit 32 in real time, thereby generating a two-phase drive control signal by feedback regulation of the output voltage Vo or output current Io.

[0078] S410: Detect whether a three-phase drive control signal is currently generated.

[0079] The control circuit detects whether the current mode is a three-phase wave generation mode or a two-phase wave generation mode, that is, detects whether a three-phase drive control signal is currently generated, and can also detect whether a two-phase drive control signal is currently generated.

[0080] If a three-phase drive control signal is currently generated, S411 is executed; if a two-phase drive control signal is currently generated, but not a three-phase drive control signal, S417 is executed.

[0081] S411: Detect whether the pre-transmitted drive signal frequency is greater than the three-phase maximum wave transmission frequency.

[0082] The control circuit detects and determines whether the frequency of the pre-transmitted drive signal currently obtained is greater than the maximum three-phase transmission frequency.

[0083] If the pre-transmitted driving signal frequency is greater than the three-phase maximum wave transmission frequency, S412 is executed; if the pre-transmitted driving signal frequency is not greater than the three-phase maximum wave transmission frequency, S416 is executed.

[0084] S412: Regulating the pulse width of the three-phase drive control signal using the output current or the output voltage.

[0085] The control circuit uses the currently acquired output voltage Vo or output current Io of the second three-phase resonant output circuit 32 to adjust the pulse width of the three-phase drive control signal in real time by adopting a pulse width modulation method.

[0086] S413: Detect whether the pulse width of the adjusted three-phase drive control signal is less than the minimum pulse width.

[0087] The control circuit further detects whether the pulse width of the adjusted three-phase drive control signal is less than the minimum pulse width.

[0088] It is worth noting that the minimum pulse width can be obtained by monitoring and calculating the stress of each switch tube in the second three-phase resonant output circuit 32 and the state of the output DC gain curve, and reasonably setting and adjusting the calculation result.

[0089] If the pulse width of the adjusted three-phase drive control signal is less than the minimum pulse width, S414 is executed; if the pulse width of the adjusted three-phase drive control signal is not less than the minimum pulse width, S415 is executed.

[0090] S414: Perform on-off adjustment on the three-phase drive control signal.

[0091] The control circuit adopts a three-phase ‌Burst mode to adjust the on-off of the three-phase drive control signal, that is, continuously sending the three-phase drive control signal to the second three-phase switch circuit 31 for a first period of time, and then stops sending the three-phase drive control signal to the second three-phase switch circuit 31 for a second period of time, and adjusts the proportion of the time of sending and stopping the wave.

[0092] It is worth noting that the Burst mode is a mode that works under light load conditions, mainly used to reduce switching losses and conduction losses and improve system efficiency. In the Burst mode, the switch tube conduction time is very short, and the frequency of the switching pulse is greatly reduced, which makes the system output voltage Vo ripple larger, but at the same time improves the system output efficiency.

[0093] S415: Send the first drive signal, the second drive signal, and the third drive signal to the first phase switch subcircuit, the second phase switch subcircuit, and the third phase switch subcircuit, respectively, to adjust the switching states of the first phase switch subcircuit, the second phase switch subcircuit, and the third phase switch subcircuit, respectively, so as to adjust the output voltage Vo or the output current Io.

[0094] The control circuit sends the first drive signal, the second drive signal and the third drive signal to the first phase switch subcircuit 311, the second phase switch subcircuit 312 and the third phase switch subcircuit 313 respectively, so that the first phase switch subcircuit 311, the second phase switch subcircuit 312 and the third phase switch subcircuit 313 change the switch state under the action of the first drive signal, the second drive signal and the third drive signal respectively, thereby adjusting the output voltage of the second three-phase resonant output circuit 32 to meet the power demand of the back-end signal function circuit.

[0095] S416: Regulate the signal frequency of the three-phase drive control signal using the output current or the output voltage.

[0096] The control circuit uses the currently acquired output voltage Vo or output current Io of the second three-phase resonant output circuit 32 to adjust the signal frequency of the three-phase drive control signal in real time by adopting a frequency regulation method.

[0097] S417: Detect whether the pre-transmitted drive signal frequency is greater than the two-phase maximum wave transmission frequency.

[0098] The control circuit detects whether the frequency of the currently acquired pre-transmitted driving signal is less than the maximum two-phase wave transmission frequency.

[0099] If the pre-transmission driving signal frequency is not greater than the maximum two-phase wave transmission frequency, S418 is executed; if the pre-transmission driving signal frequency is less than the maximum two-phase wave transmission frequency, S422 is executed.

[0100] S418: Adjust the phase difference between the first control signal and the second control signal.

[0101] The control circuit performs phase shift adjustment on the first control signal and / or the second control signal to adjust the phase difference between the first control signal and the second control signal.

[0102] Specifically, the control circuit can be to gradually reduce the phase difference between the first control signal and the second control signal, and gradually reduce the phase difference between the first control signal and the second control signal by using any reasonable functional relationship such as a linear function or an arithmetic progression function with time as the independent variable. The specific details are determined by the actual application scenario, and this application does not limit this.

[0103] S419: Detect whether the phase difference between the adjusted first control signal and the second control signal is less than the minimum phase difference.

[0104] The control circuit further detects whether the phase difference between the adjusted first control signal and the second control signal is less than a minimum phase difference.

[0105] If the adjusted phase difference between the first control signal and the second control signal is less than the minimum phase difference, S420 is executed; if the adjusted phase difference between the first control signal and the second control signal is not less than the minimum phase difference, S421 is executed.

[0106] S420: Perform on-off regulation on the first control signal and the second control signal.

[0107] The control circuit adopts a two-phase ‌Burst mode to regulate the on-off of the first control signal and the second control signal, that is, continuously sending the first control signal and the second control signal to any two of the first phase switch sub-circuit 311, the second phase switch sub-circuit 312 and the third phase switch sub-circuit 313 for a first duration, then stops sending the wave for a second duration, and adjusts the proportion of the duration of sending the wave and stopping the wave.

[0108] S421: Send the first control signal and the second control signal to any two of the first phase switch subcircuit, the second phase switch subcircuit and the third phase switch subcircuit, respectively, so as to adjust the switching states of any two of the first phase switch subcircuit, the second phase switch subcircuit and the third phase switch subcircuit, respectively, so as to adjust the output voltage Vo or the output current Io.

[0109] The control circuit sends the first control signal and the second control signal to any two of the first phase switch subcircuit 311, the second phase switch subcircuit 312 and the third phase switch subcircuit 313 respectively, so that any two of the first phase switch subcircuit 311, the second phase switch subcircuit 312 and the third phase switch subcircuit 313 change the switch state under the action of the first control signal and the second control signal respectively, thereby adjusting the output voltage Vo or the output current Io of the second three-phase resonant output circuit 32 to meet the power demand of the back-end signal function circuit.

[0110] S422: Regulate the signal frequency of the two-phase drive control signal using the output current or the output voltage.

[0111] The control circuit uses the currently acquired output voltage Vo or output current Io of the second three-phase resonant output circuit 32 of the three-phase resonant conversion circuit to adjust the signal frequency of the two-phase drive control signal in real time by adopting a frequency regulation method.

[0112] Furthermore, in one embodiment, the above S410 may be specifically replaced by: detecting whether a two-phase drive control signal is currently generated.

[0113] It is understandable that the control circuit detects whether the current mode is a three-phase wave generation mode or a two-phase wave generation mode, that is, detects whether a three-phase drive control signal is currently generated, and can also detect whether a two-phase drive control signal is currently generated.

[0114] If a two-phase drive control signal is currently generated, S417 is executed; if a three-phase drive control signal is currently generated, but not a two-phase drive control signal, S411 is executed.

[0115] This application also provides an electronic device, see Figure 5 , Figure 51 is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. In this embodiment, the electronic device 50 includes a housing 51 and a third three-phase resonant conversion circuit 52 connected to the housing 51 .

[0116] It should be noted that the third three-phase resonant conversion circuit 52 described in this embodiment is the first three-phase resonant conversion circuit 20 or the second three-phase resonant conversion circuit 30 described in any one of the above embodiments. Figure 1-Figure 4 And the related text content will not be repeated here.

[0117] The beneficial effects of the present application are as follows: Different from the prior art, the control method of the three-phase resonant conversion circuit provided by the present application obtains the output current and / or output voltage of the three-phase resonant output circuit, generates a three-phase drive control signal or a two-phase drive control signal based on a first comparison result between the output current and the two-phase maximum output current and / or a second comparison result between the output voltage and the two-phase maximum output voltage, and uses the three-phase drive control signal or the two-phase drive control signal to adjust the switch state of the three-phase switch circuit to adjust the output voltage or the output current, so that the two-phase wave generation mode and the three-phase wave generation mode can be flexibly switched in response to the changes in the output current and the output voltage, so that when the load is light or no-load, the three-phase switch circuit is controlled to work in a two-phase full-bridge mode, which is equivalent to that only two bridge arms of the three-phase switch circuit are working alternately, so as to realize two-phase wave generation, so as to ensure the stability of the output voltage and its DC gain curve state, which is helpful to improve the efficiency and stability of the three-phase resonant conversion circuit when the load is light; and when the load is heavy or high output power is required, it can also work in a three-phase interleaved parallel mode to fully utilize the advantages of the three-phase interleaved parallel.

[0118] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A control method for a three-phase resonant conversion circuit, wherein the three-phase resonant conversion circuit comprises a three-phase switching circuit and a three-phase resonant output circuit, wherein the three-phase switching circuit is coupled to the three-phase resonant output circuit and is used to couple with a power supply circuit, wherein: The control method of the three-phase resonant conversion circuit includes: Obtaining an output current and / or an output voltage of the three-phase resonant output circuit; Generate a three-phase drive control signal or a two-phase drive control signal based on a first comparison result between the output current and the two-phase maximum output current and / or a second comparison result between the output voltage and the two-phase maximum output voltage; The switching state of the three-phase switch circuit is adjusted using the three-phase drive control signal or the two-phase drive control signal to adjust the output voltage or the output current.

2. The control method of the three-phase resonant conversion circuit according to claim 1, characterized in that: The step of generating a three-phase drive control signal or a two-phase drive control signal based on a first comparison result between the output current and the two-phase maximum operating voltage and / or a second comparison result between the output voltage and the two-phase maximum output voltage comprises: Detecting whether the output current is greater than the two-phase maximum output current; If the output current is greater than the two-phase maximum output current, generating a three-phase drive control signal using the output current or the output voltage; The three-phase switch circuit includes a first-phase switch subcircuit, a second-phase switch subcircuit and a third-phase switch subcircuit coupled to each other, the first-phase switch subcircuit, the second-phase switch subcircuit and the third-phase switch subcircuit are coupled to the three-phase resonant output circuit and are used to couple with the power supply circuit; the three-phase drive control signal includes a first drive signal, a second drive signal and a third drive signal; The step of adjusting the switching state of the three-phase switch circuit by using the three-phase drive control signal or the two-phase drive control signal to adjust the output voltage or the output current includes: The first drive signal, the second drive signal, and the third drive signal are respectively sent to the first phase switch subcircuit, the second phase switch subcircuit, and the third phase switch subcircuit to respectively adjust the switching states of the first phase switch subcircuit, the second phase switch subcircuit, and the third phase switch subcircuit, thereby adjusting the output voltage or the output current.

3. The control method of the three-phase resonant conversion circuit according to claim 2, characterized in that: The control method of the three-phase resonant conversion circuit also includes: If the output current is not greater than the two-phase maximum output current, detecting whether the output voltage is greater than the two-phase maximum output voltage; If the output voltage is not greater than the two-phase maximum output voltage, detecting whether the frequency of the pre-transmitted drive signal generated by using the output current or the output voltage is greater than the three-phase maximum wave frequency; If the pre-transmitted drive signal frequency is greater than the three-phase maximum wave transmission frequency, a two-phase drive control signal is generated using the current output current or the output voltage; wherein the two-phase drive control signal includes a first control signal and a second control signal; The step of adjusting the switching state of the three-phase switch circuit by using the three-phase drive control signal or the two-phase drive control signal to adjust the output voltage or the output current includes: The first control signal and the second control signal are respectively sent to any two of the first phase switch subcircuit, the second phase switch subcircuit and the third phase switch subcircuit to respectively adjust the switching states of any two of the first phase switch subcircuit, the second phase switch subcircuit and the third phase switch subcircuit, thereby adjusting the output voltage or the output current.

4. The control method of the three-phase resonant conversion circuit according to claim 3, characterized in that: The control method of the three-phase resonant conversion circuit also includes: If the pre-transmitted drive signal frequency is not greater than the three-phase maximum wave transmission frequency, detecting whether the pre-transmitted drive signal frequency is less than the two-phase minimum wave transmission frequency; If the pre-transmitted drive signal frequency is less than the two-phase minimum wave transmission frequency, the three-phase drive control signal is generated using the current output current or the output voltage.

5. The control method of the three-phase resonant conversion circuit according to claim 4, characterized in that: The control method of the three-phase resonant conversion circuit also includes: Detecting whether the three-phase drive control signal or the two-phase drive control signal is currently generated; If the three-phase drive control signal is currently generated, detecting whether the frequency of the pre-sent drive signal is greater than the three-phase maximum wave frequency; If the pre-transmitted drive signal frequency is greater than the three-phase maximum wave transmission frequency, the pulse width of the three-phase drive control signal is adjusted using the output current or the output voltage.

6. The control method of the three-phase resonant conversion circuit according to claim 5, characterized in that: After the step of adjusting the duty cycle of the three-phase drive control signal by using the output voltage, the method further includes: Detecting whether the pulse width of the adjusted three-phase drive control signal is less than the minimum pulse width; If the pulse width of the adjusted three-phase drive control signal is smaller than the minimum pulse width, the three-phase drive control signal is on-off regulated.

7. The control method of the three-phase resonant conversion circuit according to claim 5, characterized in that: The control method of the three-phase resonant conversion circuit also includes: If the pre-transmitted drive signal frequency is not greater than the three-phase maximum wave transmission frequency, the signal frequency of the three-phase drive control signal is adjusted using the output current or the output voltage.

8. The control method of the three-phase resonant conversion circuit according to claim 4, characterized in that: The control method of the three-phase resonant conversion circuit also includes: Detecting whether the three-phase drive control signal or the two-phase drive control signal is currently generated; If the two-phase drive control signal is currently generated, detecting whether the frequency of the pre-sent drive signal is greater than the two-phase maximum wave frequency; If the pre-transmission drive signal frequency is not greater than the two-phase maximum transmission frequency, the phase difference between the first control signal and the second control signal is adjusted.

9. The control method of the three-phase resonant conversion circuit according to claim 8, characterized in that: After the step of adjusting the phase difference between the first control signal and the second control signal, the method further includes: Detecting whether the adjusted phase difference between the first control signal and the second control signal is less than a minimum phase difference; If the adjusted phase difference between the first control signal and the second control signal is smaller than the minimum phase difference, the first control signal and the second control signal are adjusted to be on and off.

10. The control method of the three-phase resonant conversion circuit according to claim 8, characterized in that: The control method of the three-phase resonant conversion circuit also includes: If the pre-transmitted driving signal frequency is less than the two-phase maximum transmitting frequency, the signal frequency of the two-phase driving control signal is adjusted using the output current or the output voltage.

11. The control method of the three-phase resonant conversion circuit according to any one of claims 2 to 10, characterized in that: Before the step of detecting whether the output current is greater than the two-phase maximum output current, the step further includes: Check whether it is the first time to power on; If it is the first time to power on, the two-phase drive control signal is generated by using the output current or the output voltage.

12. A three-phase resonant conversion circuit, characterized in that: The three-phase resonant conversion circuit includes a three-phase switching circuit, a three-phase resonant output circuit and a control circuit, wherein the three-phase switching circuit is coupled to the three-phase resonant output circuit and is used to couple with a power supply circuit, and the control circuit is coupled to the three-phase switching circuit and the three-phase resonant output circuit; Wherein, the control circuit is used to control the three-phase switching circuit by adopting the control method of the three-phase resonant conversion circuit as described in any one of claims 1-11.

13. An electronic device, characterized in that: The electronic device comprises a housing and a three-phase resonant conversion circuit connected to the housing; Wherein, the three-phase resonant conversion circuit is the three-phase resonant conversion circuit as claimed in claim 12.

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