Sampling system, control method and device of resonant converter and resonant converter

Abstract

The invention relates to a sampling system, a control method and device of a resonant converter and the resonant converter, and relates to the technical field of converter control. The sampling system comprises a controller, a selection circuit and a sampling circuit. The controller outputs a gating signal. The selection circuit outputs a trigger signal to the controller at the sampling time of the resonance current or the resonance voltage according to the gating signal. The sampling circuit is connected with the controller, samples the resonance current or the resonance voltage according to the gating signal, obtains a sampling signal and outputs the sampling signal to the controller, so that the controller records the sampling signal corresponding to the trigger signal. By simultaneously outputting the gating signal to the selection circuit and the sampling circuit, the sampling circuit synchronously acquires the corresponding sampling signal while the selection circuit outputs the trigger signal, so that the trigger signal and the sampling signal are matched one by one in the controller. Resonance current and resonance voltage with fast waveform change can be accurately sampled so that real-time resonance frequency can be calculated.

Description

Technical Field

[0001] The present application relates to the technical field of converter control, and in particular to a sampling system, a control method and device for a resonant converter, and a resonant converter. Background Art

[0002] A resonant converter is a highly efficient power conversion device widely used in various power supply systems. It utilizes a resonant module composed of components such as inductors and capacitors in the circuit to convert input power to output power by adjusting the on / off state of switching devices.

[0003] The performance of a resonant converter is closely related to its operating frequency. The resonant frequency of the resonant module is a key factor affecting the optimal operating frequency of the resonant converter. The resonant frequency determines the waveform characteristics of the current and voltage in the resonant module, which in turn affects performance indicators such as the resonant converter's conversion efficiency.

[0004] However, the resonant frequency cannot be measured directly and must be obtained indirectly by sampling the resonant voltage and resonant current and then calculating them. Therefore, how to sample the resonant voltage and resonant current in real time is an urgent problem that needs to be solved. Summary of the Invention

[0005] The embodiments of the present application provide a sampling system, a control method and device for a resonant converter, and a resonant converter, which perform real-time sampling of the resonant voltage and resonant current to obtain a real-time resonant frequency, thereby at least partially solving the above-mentioned technical problems.

[0006] In order to achieve the above object, according to a first aspect of the present application, a sampling system is provided, comprising:

[0007] A controller outputs a preset strobe signal;

[0008] A selection circuit is connected to the controller, and outputs a trigger signal to the controller at a sampling moment of the resonant current or the resonant voltage according to a selection signal;

[0009] The sampling circuit is connected to the controller, samples the resonant current or the resonant voltage according to the selection signal, obtains a sampling signal and outputs it to the controller, so that the controller records the sampling signal corresponding to the trigger signal.

[0010] Optionally, the trigger signal includes a resonant current trigger signal and a resonant voltage trigger signal, and the selection circuit includes:

[0011] a trigger signal generating subcircuit, connected to the controller, outputting a resonant voltage trigger signal when the resonant current reaches a preset phase, and outputting a resonant current trigger signal when the resonant voltage reaches a preset phase, so as to determine the sampling moment;

[0012] The selection subcircuit is connected to the trigger signal generation subcircuit and the controller, and outputs the resonant voltage trigger signal or the resonant current trigger signal to the controller according to the selection signal.

[0013] Optionally, the resonant voltage trigger signal includes a first voltage trigger signal and a second voltage trigger signal; the resonant current trigger signal includes a first current trigger signal and a second current trigger signal;

[0014] The trigger signal generating subcircuit includes a zero-crossing detection unit, an advance unit and a lag unit;

[0015] The zero-crossing detection unit performs zero-crossing detection on the resonant current to output a zero-crossing current signal when the resonant current is zero phase; or performs zero-crossing detection on the resonant voltage to output a zero-crossing voltage signal when the resonant voltage is zero phase;

[0016] The leading unit is connected to the zero-crossing detection unit, and performs an advancing shift on the phase of the zero-crossing voltage signal to obtain a first current trigger signal; or, performs an advancing shift on the phase of the zero-crossing current signal to obtain a first voltage trigger signal;

[0017] The hysteresis unit is connected to the zero-crossing detection unit, and performs a hysteresis shift on the phase of the zero-crossing voltage signal to obtain a second current trigger signal; or performs a hysteresis shift on the phase of the zero-crossing current signal to obtain a second voltage trigger signal.

[0018] Optionally, the leading unit and the lagging unit include a first comparator, a first resistor and a capacitor;

[0019] The first comparator includes a first input terminal connected to the first resistor, a second input terminal connected to the ground, and an output terminal connected to the selection subcircuit;

[0020] The first resistor includes a first end connected to the zero-crossing detection unit and a second end connected to the first input end of the first comparator;

[0021] The capacitor includes a first end connected to the second end of the first resistor and a second end connected to ground;

[0022] The resistance values of the first resistor in the leading unit and the first resistor in the lagging unit are different; the capacitance values of the capacitor in the leading unit and the capacitor in the lagging unit are different.

[0023] Optionally, the selection subcircuit includes a plurality of switch units correspondingly connected to the leading unit or the lagging unit;

[0024] The switch unit is also connected to the controller, and is turned on or off according to the selection signal to control the corresponding resonant voltage trigger signal or the resonant current trigger signal to be output to the controller.

[0025] According to a second aspect of the present application, a control method for a resonant converter is provided, which is implemented based on the above-mentioned sampling system, and the method includes:

[0026] Acquire the sampling signal output by the sampling system;

[0027] Obtaining a resonant inductance value and a resonant capacitance value according to the sampling signal;

[0028] Calculating a real-time resonant frequency according to the resonant inductance value and the resonant capacitance value;

[0029] According to the real-time resonant frequency, the operating frequency of the resonant converter is adjusted so that the resonant converter operates at the real-time resonant frequency.

[0030] Optionally, the sampling signal includes a first resonant current sampling value, a second resonant current sampling value, a first resonant voltage sampling value, and a second resonant voltage sampling value determined according to the trigger signal;

[0031] Obtaining a resonant inductance value and a resonant capacitance value according to the sampling signal includes:

[0032] When the resonant voltage is at zero phase, calculating a current peak value according to the first resonant current sampling value and the second resonant current sampling value, calculating a voltage variation according to the first resonant voltage sampling value and the second resonant voltage sampling value, and generating the resonant capacitance value according to the current peak value and the voltage variation;

[0033] When the resonant current is in zero phase, a voltage peak is calculated based on the first resonant voltage sampling value and the second resonant voltage sampling value, a current variation is calculated based on the first resonant current sampling value and the second resonant current sampling value, and the resonant inductance value is generated based on the voltage peak and the current variation.

[0034] Optionally, calculating the real-time resonant frequency according to the resonant inductance value and the resonant capacitance value includes:

[0035] The resonant inductance value and the resonant capacitance value are input into a preset resonant function to generate the real-time resonant frequency.

[0036] Optionally, the resonant converter includes a power factor correction module and the resonant module, and adjusting the operating frequency of the resonant converter according to the real-time resonant frequency includes:

[0037] comparing the operating frequency and the real-time resonant frequency to obtain a comparison result;

[0038] According to the comparison result, the control voltage of the power factor correction module is adjusted with a preset gradient to adjust the operating frequency of the resonance module.

[0039] Optionally, adjusting the control voltage of the power factor correction module with a preset gradient according to the comparison result to adjust the operating frequency of the resonance module includes:

[0040] If the comparison result shows that the operating frequency is less than the real-time resonant frequency, increasing the control voltage of the power factor correction module to increase the operating frequency;

[0041] If the comparison result shows that the operating frequency is greater than the real-time resonant frequency, the control voltage of the power factor correction module is reduced to reduce the operating frequency.

[0042] According to a third aspect of the present application, a control system for a resonant converter is provided, comprising:

[0043] A sampling module, used to obtain a sampling signal output by a sampling system;

[0044] A resonance parameter generating module, configured to obtain a resonance inductance value and a resonance capacitance value according to the sampling signal;

[0045] A resonant frequency generating module, configured to calculate a real-time resonant frequency according to the resonant inductance value and the resonant capacitance value;

[0046] The regulating module is configured to adjust the operating frequency of the resonant converter according to the real-time resonant frequency, so that the resonant converter operates at the real-time resonant frequency.

[0047] According to a fourth aspect of the present application, a control device is provided, comprising a memory and a processor; a computer program executed by the processor is stored on the processor; when the computer program is executed by the processor, the processor executes the control method of the resonant converter as described above.

[0048] According to a fifth aspect of the present application, a resonant converter is provided, comprising the above-mentioned sampling system, or comprising the above-mentioned controller.

[0049] To summarize, the embodiment of the present application uses a preset selection signal output by the controller to clarify that the object currently to be sampled is one of the resonant voltage or the resonant current, and outputs the selection signal to the selection circuit so that the selection circuit outputs a trigger signal at the sampling moment of the resonant voltage or the resonant current. At the same time, the selection signal is output to the sampling circuit so that the sampling circuit samples the resonant current or resonant voltage represented by the selection signal, thereby obtaining a sampling signal that matches the trigger signal. By simultaneously outputting the selection signal to the selection circuit and the sampling circuit, the sampling circuit can synchronously collect the corresponding sampling signal while the selection circuit outputs the trigger signal, so that the trigger signal and the sampling signal can be matched one-to-one in the controller, and then the resonant current and resonant voltage with faster waveform changes can be accurately sampled, so as to calculate the real-time resonant frequency.

[0050] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] To more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0052] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings, wherein the same drawing numbers represent the same parts in the following description.

[0053] Figure 1 is a schematic diagram of a sampling system provided in an exemplary embodiment of the present disclosure;

[0054] Figure 2 is a schematic structural diagram of a resonance module in an exemplary embodiment of the present disclosure;

[0055] Figure 3 is a schematic diagram of a selection circuit provided in an exemplary embodiment of the present disclosure;

[0056] Figure 4 is a schematic diagram of sampling of resonance current and resonance voltage provided in an exemplary embodiment of the present disclosure;

[0057] Figure 5 is a connection structure diagram of a selection circuit provided in an exemplary embodiment of the present disclosure;

[0058] Figure 6 is a flow chart of a control method of a resonant converter provided in an exemplary embodiment of the present disclosure;

[0059] Figure 7 is a flow chart of a method for generating a resonant capacitance value and a resonant inductance value provided in an exemplary embodiment of the present disclosure;

[0060] Figure 8 is a flow chart of a method for adjusting operating frequency provided in an exemplary embodiment of the present disclosure.

[0061] Explanation of the accompanying symbols: 1. Controller; 2. Selection circuit; 21. Trigger signal generation subcircuit; 211. Zero-crossing detection unit; 212. Lead unit; 213. Lag unit; 22. Selection subcircuit; 221. Switch unit; 3. Sampling circuit. DETAILED DESCRIPTION

[0062] 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 embodiments described 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 those skilled in the art without creative work are within the scope of protection of the present application.

[0063] According to the first aspect of this application, referring to Figures 1 to 5 The present disclosure provides a sampling system, comprising a controller 1, a selection circuit 2, and a sampling circuit 3. The controller 1 outputs a preset selection signal. The selection circuit 2 is connected to the controller 1 and, based on the selection signal, outputs a trigger signal to the controller 1 at the sampling moment of the resonant current or resonant voltage. The sampling circuit 3 is connected to the controller 1 and samples the resonant current or resonant voltage based on the selection signal, obtains a sampling signal, and outputs it to the controller 1, so that the controller 1 records the sampling signal corresponding to the trigger signal.

[0064] Combine Figure 2 , Figure 2 Figure 1 is a schematic diagram of a resonant module, which includes a resonant capacitor Cr and a resonant inductor Lr connected in series with both ends of the primary coil of the transformer. To sample the resonant voltage and resonant current, a voltage sampler V and a current sampler A can be provided. For example, the current sampler A can be connected in series with the resonant inductor Lr to sample the resonant current and obtain a resonant current sampling value. The voltage sampler V can be connected in parallel with the resonant capacitor Cr to sample the resonant voltage and obtain a resonant voltage sampling value.

[0065] The phase difference between the resonant voltage and the resonant current is ninety degrees, that is, when the resonant current is at zero phase, the resonant voltage is at a peak phase; when the resonant voltage is at zero phase, the resonant current is at a peak phase.

[0066] As an example, when it is necessary to calculate the resonant capacitance and resonant inductance, since the resonant capacitance is related to the change in the resonant voltage, and the resonant inductance is related to the change in the resonant current, in order to accurately sample the change in the resonant current and the resonant voltage, it is necessary to sample the resonant voltage and the resonant current at least twice within one resonant cycle, that is, the sampling moments include the first moment, the second moment, the third moment, and the fourth moment, so as to sample the resonant voltage and the resonant current separately at four different sampling moments. The trigger signal corresponds one-to-one to the sampling moment, that is, a corresponding trigger signal is output at each sampling moment. For example, the trigger signal may include a resonant current trigger signal and a resonant voltage trigger signal, and the resonant voltage trigger signal includes a first voltage trigger signal and a second voltage trigger signal, and the resonant current trigger signal includes a first current trigger signal and a second current trigger signal.

[0067] As an example, the strobe signal can be preset based on the number of signals to be sampled and the switching frequency of the switch tube in the resonant module, that is, the operating frequency of the resonant frequency. When the trigger signal includes a first voltage trigger signal, a second voltage trigger signal, a first current trigger signal, and a second current trigger signal, that is, the number of signals to be sampled is four, the strobe signal needs to be able to distinguish the four signals. In this case, the strobe signal may include a first strobe signal S1 and a second strobe signal S2, and the four signals are represented by the combination of the first strobe signal S1 and the second strobe signal S2. For example, when the first selection signal S1 and the second selection signal S2 are both at a low level, the selection signal indicates that the resonant voltage at the first sampling moment needs to be sampled, so that the selection circuit 2 outputs a first voltage trigger signal at the first sampling moment of the resonant voltage; when the first selection signal S1 is at a high level and the second selection signal S2 is at a low level, the selection circuit 2 outputs a second voltage trigger signal at the second sampling moment of the resonant voltage; when the first selection signal S1 is at a low level and the second selection signal S2 is at a high level, the selection circuit 2 outputs a first current trigger signal at the third sampling moment of the resonant current; when the first selection signal S1 and the second selection signal S2 are both at a high level, the selection circuit 2 outputs a second current trigger signal at the fourth sampling moment of the resonant current.

[0068] In the above embodiment, the controller 1 outputs a preset selection signal to clarify whether the object currently to be sampled is one of the resonant voltage or the resonant current, and outputs the selection signal to the selection circuit 2, so that the selection circuit 2 outputs a trigger signal at the sampling moment of the resonant voltage or the resonant current. At the same time, the selection signal is output to the sampling circuit 3, so that the sampling circuit 3 samples the resonant current or resonant voltage represented by the selection signal, thereby obtaining a sampling signal that matches the trigger signal. By outputting the selection signal to the selection circuit 2 and the sampling circuit 3 at the same time, the sampling circuit 3 can synchronously collect the corresponding sampling signal while the selection circuit 2 outputs the trigger signal, so that the trigger signal and the sampling signal can be matched one by one in the controller 1, and then the resonant current and resonant voltage with faster waveform changes can be accurately sampled, so as to calculate the real-time resonant frequency.

[0069] Reference Figure 3 In some embodiments, the selection circuit 2 includes a trigger signal generation subcircuit 21 and a selection subcircuit 22. The trigger signal generation subcircuit 21 is connected to the controller 1 and outputs a resonant voltage trigger signal when the resonant current reaches a preset phase, and outputs a resonant current trigger signal when the resonant voltage reaches a preset phase, to determine the sampling time. The selection subcircuit is connected to the trigger signal generation subcircuit 21 and the controller 1 and outputs a resonant voltage trigger signal or a resonant current trigger signal to the controller 1 according to the selection signal.

[0070] In the above embodiment, the trigger signal generating sub-circuit 21 is connected to the controller 1, and can output a resonant voltage trigger signal when the resonant current reaches a preset phase, and output a resonant current trigger signal when the resonant voltage reaches a preset phase, thereby forming a mutual trigger between the resonant voltage and the resonant current based on the phase relationship between the resonant voltage and the resonant current, thereby ensuring the accuracy of the sampling time.

[0071] In some embodiments, the trigger signal generating subcircuit 21 includes a zero-crossing detection unit 211, an advance unit 212, and a lag unit 213. The zero-crossing detection unit 211 performs zero-crossing detection on the resonant current to output a zero-crossing current signal when the resonant current is zero phase; or, performs zero-crossing detection on the resonant voltage to output a zero-crossing voltage signal when the resonant voltage is zero phase. The advance unit 212 is connected to the zero-crossing detection unit 211 and performs an advance shift on the phase of the zero-crossing voltage signal to obtain a first current trigger signal; or, performs an advance shift on the phase of the zero-crossing current signal to obtain a first voltage trigger signal; the lag unit 213 is connected to the zero-crossing detection unit 211 and performs a lag shift on the phase of the zero-crossing voltage signal to obtain a second current trigger signal; or, performs a lag shift on the phase of the zero-crossing current signal to obtain a second voltage trigger signal.

[0072] As an example, when the resonant current is at zero potential, the resonant voltage is at a peak potential, the resonant voltage is relatively flat, and is approximately a DC signal. This is the sampling moment of the resonant voltage, and the trigger signal generation subcircuit 21 generates a corresponding trigger signal and outputs it to the controller 1 so that the controller 1 can read the corresponding resonant voltage sampling value; similarly, when the resonant current is at zero potential, the resonant current is at a peak potential, the resonant current is relatively flat, and is approximately a DC signal. This is the sampling moment of the resonant current, and the trigger signal generation subcircuit 21 generates a corresponding trigger signal and outputs it to the controller 1 so that the resonant current sampling value can be read. It should be noted that if only the peak value of the resonant current or resonant voltage needs to be sampled, the current zero-crossing signal can be directly used as the resonant voltage trigger signal, and the voltage zero-crossing signal can be used as the resonant current trigger signal, so that the sampling circuit 3 samples the peak value of the resonant voltage when the resonant current is at zero potential, and samples the peak value of the resonant current when the resonant voltage is at zero potential.

[0073] As an example, the preset phase may include an advance phase and a lag phase after the zero phase is advanced or lagged. When calculating the resonant capacitance and resonant inductance, it is necessary to sample the resonant voltage and the resonant current at least twice in one resonant cycle to calculate the resonant current change and the resonant voltage change. Therefore, in order to more accurately calculate the resonant current change and the resonant voltage change, the moment when the current change and the resonant voltage change per unit time are larger can be taken as the sampling moment. For example, the waveforms of the resonant current and the resonant voltage are both sinusoidal waveforms, and the current change or the resonant voltage change is the largest at zero potential. Therefore, the moment corresponding to the advance phase and the lag phase after the zero phase advance or lag displacement can be selected as the sampling moment.

[0074] Combine Figure 4 , Figure 4 It is a schematic diagram of resonant current and resonant voltage sampling. Figure 4 Where ILr represents the resonant current, Vcr represents the resonant voltage, Figure 4 In (a), t0 is the moment when the resonant current is at zero potential, t1 is the sampling moment corresponding to the output of the first voltage trigger signal by the trigger signal generating sub-circuit 21, and t2 is the sampling moment corresponding to the output of the second voltage trigger signal by the trigger signal generating sub-circuit 21; u1 represents the first resonant voltage sampling value, and u2 represents the second resonant voltage sampling value; in Figure 4 In (b), t0 is the moment when the resonant voltage is at zero potential, t3 is the sampling moment corresponding to the output of the first current trigger signal by the trigger signal generation subcircuit 21, and t4 is the sampling moment corresponding to the output of the second current trigger signal by the trigger signal generation subcircuit 21; i1 represents the first resonant current sampling value, and i2 represents the second resonant current sampling value;

[0075] In the above embodiment, the resonant voltage and the resonant current are subjected to zero-crossing detection by the zero-crossing detection unit 211. Zero-crossing detection is easier to implement than peak detection. Therefore, after the zero-crossing voltage signal is advanced or delayed, the first current trigger signal and the second current trigger signal are output. After the zero-crossing current signal is advanced or delayed, the first voltage trigger signal and the second voltage trigger signal are output, thereby realizing the generation of the resonant voltage trigger signal and the resonant current trigger signal.

[0076] Reference Figure 5 As an example, the lead unit 212 and the lag unit 213 include a first comparator U1, a first resistor R1, and a capacitor C. The first comparator U1 includes a first input terminal connected to the first resistor R1, a second input terminal connected to ground, and an output terminal connected to the selection subcircuit. The first resistor R1 includes a first terminal connected to the zero-crossing detection unit 211 and a second terminal connected to the first input terminal of the first comparator U1. The capacitor C includes a first terminal connected to the second terminal of the first resistor R1 and a second terminal connected to ground.

[0077] The resistance values of the first resistor R1 in the leading unit 212 and the first resistor R1 in the lagging unit 213 are different. The capacitance values of the capacitor C in the leading unit 212 and the capacitor C in the lagging unit 213 are different. For example, the leading time and the lagging time are set to Ts / 20, where Ts is the switching frequency of the switch tube in the resonant module. When Ts is 100KHz, the period is 10us, and the leading time and the lagging time are 0.5us. Since capacitors and resistors can only delay time, the delay time of the first resistor R1 and the capacitor C in the leading unit 212 can be set to 9.5us. For example, the resistance value of the first resistor R1 in the leading unit 212 can be 950Ω, and the capacitance value of the capacitor C can be 100nF. The delay time of the first resistor R1 and the capacitor C of the hysteresis unit 213 can be set to 0.5 μs. For example, the resistance value of the first resistor R1 of the hysteresis unit 213 can be 50 Ω, and the capacitance value of the capacitor C can be 100 nF. In this way, the phase advance shift or lag shift of the zero-crossing voltage signal and the zero-crossing current signal is achieved.

[0078] As an example, the leading unit 212 and the lagging unit 213 further include a second resistor R2 , which includes a first end connected to the second input end of the first comparator U1 and a second end grounded. The second resistor R2 is a pull-down resistor.

[0079] In the above embodiment, both phase advance adjustment and phase lag adjustment can be achieved by setting the resistance of the first resistor R1 and the capacitance of the capacitor C, and the structure is simpler.

[0080] As an example, the zero-crossing detection unit 211 includes a second comparator U2 and a third resistor R3, the second comparator U2 includes a first input terminal connected to the resonant current or voltage, a second terminal connected to the first terminal of the third resistor R3, and an output terminal connected to the leading unit 212 and the lagging unit 213 to output a zero-crossing voltage signal or a zero-crossing current signal to the leading unit 212 and the lagging unit 213.

[0081] In the above embodiment, zero-crossing detection is achieved by comparing the potential between the resonant current or resonant voltage and the ground, and a high-level signal is output when the resonant current or resonant voltage is at zero potential to form a zero-crossing voltage signal and a zero-crossing current signal in the form of a square wave, so that the leading unit 212 and the lagging unit 213 can perform phase shift.

[0082] In some embodiments, the selection subcircuit includes multiple switch units 221 correspondingly connected to the leading unit 212 or the lagging unit 213, and the switch unit 221 is also connected to the controller 1, and is turned on or off according to the selection signal to control the corresponding resonant voltage trigger signal or resonant current trigger signal to be output to the controller 1.

[0083] According to the second aspect of the present application, a control method for a resonant converter is provided, which is implemented based on the above-mentioned sampling system, with reference to Figure 6 The method includes steps S101 to S104, which are described in detail below.

[0084] Step S101: Acquire a sampling signal output by a sampling system.

[0085] As an example, the sampling signal includes a first resonant current sampling value, a second resonant current sampling value, a first resonant voltage sampling value, and a second resonant voltage sampling value determined according to the trigger signal.

[0086] Step S102: obtaining a resonant inductance value and a resonant capacitance value according to the sampling signal.

[0087] Step S103: Calculate the real-time resonant frequency according to the resonant inductance and the resonant capacitance.

[0088] As an example, step S103 may include inputting the resonant inductance value and the resonant capacitance value into a preset resonant function to generate a real-time resonant frequency.

[0089] As an example, the real-time resonant frequency can be expressed as Among them, Lr0 is the resonant inductance value; Cr0 is the resonant capacitance value.

[0090] Step S104: adjusting the operating frequency of the resonant converter according to the real-time resonant frequency, so that the resonant converter operates at the real-time resonant frequency.

[0091] For example, at the real-time resonant frequency, the resonant inductance and resonant capacitance cancel each other out, making the resonant module purely resistive and achieving the highest energy transfer efficiency. Furthermore, at the real-time resonant frequency, the amplitudes of the resonant current and resonant voltage reach their maximum, enabling the resonant converter to transfer more energy.

[0092] In the above embodiment, by sampling the resonant current and voltage in real time, calculating the values of the resonant inductance and capacitance, and then calculating the real-time resonant frequency, the converter's operating frequency is adjusted based on this frequency, ensuring that the resonant converter always operates at the optimal frequency, thereby improving the efficiency and stability of the resonant converter. This avoids the problem of resonant converter operating frequency shift and reduced efficiency caused by resonant device parameter design deviations or operational aging failures.

[0093] Reference Figure 7 In some embodiments, step S102 includes steps S1021 and S1022, which are described in detail below.

[0094] Step S1021: When the resonant voltage is at zero phase, the current peak value is calculated according to the first resonant current sampling value and the second resonant current sampling value, the voltage variation is calculated according to the first resonant voltage sampling value and the second resonant voltage sampling value, and the resonant capacitance value is generated according to the current peak value and the voltage variation.

[0095] As an example, the resonant capacitance value can be expressed as Among them, u2-u1 represents the voltage change; I represents the current peak value, which can be the average of the first resonant current sampling value and the second resonant current sampling value; t11 represents the sampling interval of the voltage change. For example, the current peak value I = 26.7A, the second resonant voltage sampling value u2 = 49.94V, the first resonant voltage sampling value u1 = -69.6V, t11 = 1.003e^-6 seconds, then the resonant capacitance value is

[0096] Step S1022: When the resonant current is at zero phase, a voltage peak is calculated according to the first resonant voltage sampling value and the second resonant voltage sampling value, a current variation is calculated according to the first resonant current sampling value and the second resonant current sampling value, and a resonant inductance value is generated according to the voltage peak and the current variation.

[0097] The resonant inductance value can be expressed as Where i2-i1 represents the current change; u represents the voltage peak, which can be the average of the first resonant voltage sampling value and the second resonant voltage sampling value; t12 represents the sampling interval of the current change. For example, t12 = 1.003e^-6 seconds; the voltage peak u = 219.7V, the second resonant current sampling value i2 = 8.007A, and the first resonant current sampling value i2 = -8.196A, then the resonant inductance value is

[0098] Reference Figure 8 In some embodiments, the resonant converter includes a power factor correction module and a resonant module, and step S104 may include steps S1041 and S1042, which are described in detail below.

[0099] Step S1041: Compare the operating frequency and the real-time resonant frequency to obtain a comparison result.

[0100] Step S1042: According to the comparison result, the control voltage of the power factor correction module is adjusted with a preset gradient to adjust the operating frequency of the resonance module.

[0101] As an example, step S1042 may include steps S10421 to S104212, which are described in detail below.

[0102] Step S10421: If the comparison result indicates that the operating frequency is less than the real-time resonant frequency, the control voltage of the power factor correction module is increased to increase the operating frequency.

[0103] Step S104212: If the comparison result indicates that the operating frequency is greater than the real-time resonant frequency, the control voltage of the power factor correction module is reduced to reduce the operating frequency.

[0104] According to a third aspect of the present application, a control system for a resonant converter is provided, comprising a sampling module, a resonant parameter generating module, a resonant frequency generating module, and an adjusting module.

[0105] The sampling module is used to obtain the sampling signal output by the sampling system.

[0106] The resonance parameter generation module is used to obtain the resonance inductance value and the resonance capacitance value according to the sampling signal.

[0107] The resonant frequency generation module is used to calculate the real-time resonant frequency according to the resonant inductance value and the resonant capacitance value.

[0108] The regulating module is used to adjust the operating frequency of the resonant converter according to the real-time resonant frequency, so that the resonant converter operates at the real-time resonant frequency.

[0109] The control system of the resonant converter has all the beneficial effects of the control method of the resonant converter described above, which will not be described in detail in this disclosure.

[0110] According to a fourth aspect of the present application, a control device is provided, comprising a memory and a processor, wherein the processor stores a computer program to be executed by the processor; when the computer program is executed by the processor, the processor executes the control method of the resonant converter as described above.

[0111] According to a fifth aspect of the present application, a resonant converter is provided, comprising the above-mentioned sampling system, or comprising the above-mentioned controller 1 .

[0112] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0113] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0114] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0115] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. Although the descriptions of each embodiment in the embodiments of the present application have different focuses, for parts that are not described in detail in a certain embodiment, please refer to the relevant embodiments of other embodiments. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A sampling system, characterized in that: include: A controller outputs a preset strobe signal; A selection circuit is connected to the controller and outputs a trigger signal to the controller at a sampling moment of the resonant current or the resonant voltage according to the selection signal; The sampling circuit is connected to the controller, samples the resonant current or the resonant voltage according to the selection signal, obtains a sampling signal and outputs it to the controller, so that the controller records the sampling signal corresponding to the trigger signal.

2. The sampling system according to claim 1, characterized in that The trigger signal includes a resonant current trigger signal and a resonant voltage trigger signal, and the selection circuit includes: a trigger signal generating subcircuit, connected to the controller, outputting a resonant voltage trigger signal when the resonant current reaches a preset phase, and outputting a resonant current trigger signal when the resonant voltage reaches a preset phase, so as to determine the sampling moment; The selection subcircuit is connected to the trigger signal generation subcircuit and the controller, and outputs the resonant voltage trigger signal or the resonant current trigger signal to the controller according to the selection signal.

3. The sampling system according to claim 2, characterized in that The resonant voltage trigger signal includes a first voltage trigger signal and a second voltage trigger signal; the resonant current trigger signal includes a first current trigger signal and a second current trigger signal; The trigger signal generating subcircuit includes a zero-crossing detection unit, an advance unit and a lag unit; The zero-crossing detection unit performs zero-crossing detection on the resonant current to output a zero-crossing current signal when the resonant current is zero phase; or performs zero-crossing detection on the resonant voltage to output a zero-crossing voltage signal when the resonant voltage is zero phase; The leading unit is connected to the zero-crossing detection unit, and performs an advancing shift on the phase of the zero-crossing voltage signal to obtain a first current trigger signal; or, performs an advancing shift on the phase of the zero-crossing current signal to obtain a first voltage trigger signal; The hysteresis unit is connected to the zero-crossing detection unit, and performs a hysteresis shift on the phase of the zero-crossing voltage signal to obtain a second current trigger signal; or performs a hysteresis shift on the phase of the zero-crossing current signal to obtain a second voltage trigger signal.

4. The sampling system according to claim 3, characterized in that The lead unit and the lag unit include a first comparator, a first resistor and a capacitor; The first comparator includes a first input terminal connected to the first resistor, a second input terminal connected to the ground, and an output terminal connected to the selection subcircuit; The first resistor includes a first end connected to the zero-crossing detection unit and a second end connected to the first input end of the first comparator; The capacitor includes a first end connected to the second end of the first resistor and a second end connected to ground; The resistance values of the first resistor in the leading unit and the first resistor in the lagging unit are different; the capacitance values of the capacitor in the leading unit and the capacitor in the lagging unit are different.

5. The sampling system according to claim 4, characterized in that The selection subcircuit includes a plurality of switch units correspondingly connected to the leading unit or the lagging unit; The switch unit is also connected to the controller and is turned on or off according to the selection signal to control the corresponding resonant voltage trigger signal or the resonant current trigger signal to be output to the controller.

6. A control method for a resonant converter, implemented based on the sampling system according to any one of claims 1 to 5, characterized in that: The method comprises: Acquire the sampling signal output by the sampling system; Obtaining a resonant inductance value and a resonant capacitance value according to the sampling signal; Calculating a real-time resonant frequency according to the resonant inductance value and the resonant capacitance value; According to the real-time resonant frequency, the operating frequency of the resonant converter is adjusted so that the resonant converter operates at the real-time resonant frequency.

7. The control method of the resonant converter according to claim 6, wherein: The sampling signal includes a first resonant current sampling value, a second resonant current sampling value, a first resonant voltage sampling value, and a second resonant voltage sampling value determined according to the trigger signal; Obtaining a resonant inductance value and a resonant capacitance value according to the sampling signal includes: When the resonant voltage is at zero phase, calculating a current peak value according to the first resonant current sampling value and the second resonant current sampling value, calculating a voltage variation according to the first resonant voltage sampling value and the second resonant voltage sampling value, and generating the resonant capacitance value according to the current peak value and the voltage variation; When the resonant current is in zero phase, a voltage peak is calculated based on the first resonant voltage sampling value and the second resonant voltage sampling value, a current variation is calculated based on the first resonant current sampling value and the second resonant current sampling value, and the resonant inductance value is generated based on the voltage peak and the current variation.

8. The control method of the resonant converter according to claim 7, wherein: The calculating the real-time resonant frequency according to the resonant inductance value and the resonant capacitance value includes: The resonant inductance value and the resonant capacitance value are input into a preset resonant function to generate the real-time resonant frequency.

9. The control method of the resonant converter according to claim 7, wherein: The resonant converter includes a power factor correction module and a resonant module, and adjusting the operating frequency of the resonant converter according to the real-time resonant frequency includes: comparing the operating frequency and the real-time resonant frequency to obtain a comparison result; According to the comparison result, the control voltage of the power factor correction module is adjusted with a preset gradient to adjust the operating frequency of the resonance module.

10. The control method of the resonant converter according to claim 9, characterized in that: The step of adjusting the control voltage of the power factor correction module with a preset gradient according to the comparison result to adjust the operating frequency of the resonance module includes: If the comparison result indicates that the operating frequency is less than the real-time resonant frequency, increasing the control voltage of the power factor correction module to increase the operating frequency; If the comparison result indicates that the operating frequency is greater than the real-time resonant frequency, the control voltage of the power factor correction module is reduced to reduce the operating frequency.

11. A control device, characterized in that: include: Memory; processor; The processor has stored thereon a computer program to be executed by the processor; When the computer program is executed by the processor, the processor is caused to perform the control method of the resonant converter according to any one of claims 6 to 10.

12. A resonant converter, characterized in that: The method comprises the sampling system according to any one of claims 1 to 5, or the control device according to claim 11.

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