Quasi-single-stage AC-DC power conversion device and control method thereof

Abstract

The invention discloses a quasi-single-stage AC-DC power conversion device and a control method thereof. The device comprises a single-phase AC power supply, a totem pole PFC circuit, a bus filter capacitor Cbus, a bus and a full-bridge LLC resonant circuit. The totem pole PFC circuit comprises a power frequency bridge arm, a high frequency bridge arm and a power inductor L; the power frequency bridge arm comprises a first switch tube S1 and a second switch tube S2; the high-frequency bridge arm comprises a third switch tube Sg1 and a fourth switch tube Sg2; the L end of the single-phase alternating-current power supply is connected to the source electrode of the first switching tube S1; the N end of the single-phase alternating-current power supply is connected to the source electrode of the third switching tube Sg1 through a power inductor L; a bus filter capacitor Cbus is connected in parallel between the totem-pole PFC circuit and the full-bridge LLC resonant circuit through a bus; and the bus filter capacitor Cbus is a thin-film capacitor. The advantages of the two-stage topology and the single-stage topology are complemented, large electrolytic capacitance between the two-stage topology can be eliminated, the power density is improved, the voltage gain range is enlarged, and a high power factor is kept.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronics, in particular to a single-phase totem pole PFC circuit and an isolated soft-switching LLC resonant circuit, and specifically to a quasi-single-stage AC-DC power conversion device and a control method thereof. BACKGROUND

[0002] An AC-DC power supply is a power conversion device used to convert alternating current (AC) to direct current (DC). AC is a common form of power in the power grid, while many electronic devices (such as computers, communication devices, etc.) require DC to work, so AC-DC power supply is needed for conversion.

[0003] AC-DC power supply for high power application scenarios requires power factor correction (PFC) technology to meet the requirements of the power grid for harmonic current and power factor. PFC technology is used to improve the power factor of power equipment. In order to meet the requirements of the power grid for harmonic current and power factor, a two-stage topology structure is usually used in the prior art, which realizes decoupling between stages by connecting a large-capacity electrolytic capacitor between the PFC stage and the DC-DC converter, and the control strategy is relatively simple, but there are problems such as too large volume of electrolytic capacitor and reduced power density. In order to solve this problem, in recent years, LLC resonant circuit has been used to design single-stage AC-DC circuit with PFC technology. The advantage of this solution is compact structure and low cost, but since the LLC resonant cavity needs to simultaneously bear the functions of power factor correction and overall system gain adjustment, it leads to difficulties in resonant parameter design, limited voltage gain adjustment range, and low power factor. Therefore, in order to solve the problems of too large volume of electrolytic capacitor between stages of two-stage topology, high on-state loss of switch tube in the latter stage, difficult parameter design of single-stage topology, and narrow voltage gain range, it is very meaningful to research new AC-DC power conversion technology. SUMMARY

[0004] In view of the above-mentioned defects of the prior art, the present application provides a quasi-single-stage AC-DC power conversion device and a control method thereof, which complements the advantages of two-stage topology and single-stage topology, can eliminate the large electrolytic capacitor between stages of two-stage topology, improve power density, increase voltage gain range, and maintain high power factor.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] In a first aspect, a quasi-single-stage AC-DC power conversion device comprises: a single-phase AC power supply, a totem pole PFC circuit, a bus filter capacitor Cbus, a bus, and a full-bridge LLC resonant circuit.

[0007] The totem pole PFC circuit comprises a power frequency bridge arm, a high-frequency bridge arm, and a power inductor L.

[0008] The power frequency bridge arm comprises a first switch tube S1 and a second switch tube S2, and the source of the first switch tube S1 is connected with the drain of the second switch tube S2;

[0009] The high-frequency bridge arm comprises a third switch tube Sg1 and a fourth switch tube Sg2, and the source of the third switch tube Sg1 is connected with the drain of the fourth switch tube Sg2;

[0010] The L end of the single-phase alternating current power supply is connected to the source of the first switch tube S1;

[0011] The N end of the single-phase alternating current power supply is connected to the source of the third switch tube Sg1 through the power inductor L;

[0012] The bus filter capacitor Cbus is connected in parallel between the totem pole PFC circuit and the full-bridge LLC resonant circuit through the bus;

[0013] The bus filter capacitor Cbus is a thin-film capacitor.

[0014] As a preferred, the bus filter capacitor Cbus has a capacitance value of 2.2uf.

[0015] As a preferred, the full-bridge LLC resonant circuit comprises a full-wave rectification output circuit, an output filter capacitor Co and a load resistor Ro, and the output filter capacitor Co is connected in parallel between the output end of the full-wave rectification output circuit and the load resistor Ro.

[0016] In a second aspect, a control method of a quasi-single-stage AC-DC power conversion device comprises the following steps:

[0017] S1, collecting the inductance current IL of the power inductor L, the output voltage Vo between the output filter capacitor Co, the bus voltage Vbus between the bus filter capacitor Cbus, and the phase information PH of the single-phase alternating current power supply;

[0018] S2, subtracting the output voltage Vo from a preset reference voltage Vref to obtain a calculation result one Verror, and then performing amplitude limiting processing on the calculation result one Verror after adjusting by a proportional integral regulator to obtain a voltage modulation signal Vc;

[0019] S3, multiply the voltage modulation signal Vc with the phase sine value SinPH of the single-phase alternating power supply to obtain a sinusoidal current reference signal Iref matched with the input voltage phase of the single-phase alternating power supply; subtract the sinusoidal current reference signal Iref from the inductor current IL to obtain a second calculation result Ierror; adjust the second calculation result Ierror through a proportional resonant regulator to obtain a current modulation signal Ic;

[0020] S4, compare the current modulation signal Ic with a high-frequency triangular carrier Vs1 to obtain a high-frequency bridge arm switch tube driving signal; control the output voltage Vo to reach the preset reference voltage Vref according to the high-frequency bridge arm switch tube driving signal;

[0021] S5, obtain an input voltage phase and a square wave signal in phase with the input voltage phase according to the phase information PH; drive the power frequency bridge arm according to the square wave signal, drive the first switch tube S1 to be always on and the second switch tube S2 to be off in the positive half cycle of the input voltage; drive the second switch tube S2 to be always on and the first switch tube S1 to be off in the negative half cycle of the input voltage.

[0022] S6, adopt a lookup table method to obtain a full-bridge LLC modulation signal Vc_llc from the bus voltage Vbus through the lookup table, and realize frequency conversion control on the full-bridge LLC resonant circuit through the full-bridge LLC modulation signal Vc_llc.

[0023] As a preferred, the phase information PH is collected by a zero-crossing phase-locked loop (PLL) method.

[0024] Compared with the prior art, the beneficial effects of the present application are embodied in:

[0025] 1. In the traditional two-stage topology, a large-capacity electrolytic capacitor is needed to be connected between the PFC stage and the DC-DC converter for inter-stage decoupling to smooth the DC bus voltage. However, the large electrolytic capacitor has large volume, short service life, and large equivalent series resistance in high-frequency applications, resulting in increased loss. The present application replaces the large electrolytic capacitor with a small-capacitance film capacitor Cbus, which effectively filters out high-frequency ripples and avoids the volume and loss problems caused by the large electrolytic capacitor. The present application greatly reduces the size of the capacitor on the bus, improves the power density and reliability of the circuit. Due to the small volume, high voltage resistance and good high-frequency characteristics of the film capacitor, the high-frequency ripples can be effectively filtered out without increasing additional loss, thereby improving the performance and service life of the entire circuit.

[0026] 2. The bus voltage exhibits a continuous half-wave waveform, and the voltage across the LLC switch is constantly changing but always remains lower than the high-voltage bus voltage of a traditional two-stage topology, significantly reducing the switching losses. In a traditional two-stage topology, the switching transistors of the subsequent DC-DC converter need to withstand a high bus voltage, resulting in significant conduction losses. This invention processes the input voltage through a pre-stage totem-pole PFC circuit, causing the bus voltage to exhibit a continuous half-wave waveform. The voltage across the LLC switch is constantly changing but always remains lower than the high-voltage bus voltage of a traditional two-stage topology. This design significantly reduces the conduction losses of the subsequent switching transistors and improves circuit efficiency. Since the conduction losses of the switching transistors are proportional to the on-voltage, reducing the on-voltage effectively reduces the heat generated by the switching transistors, improving circuit efficiency and reliability.

[0027] 3. The pre-amplifier totem-pole PFC provides voltage gain capability to the system. Compared to a single-stage AC-DC LLC circuit, this reduces the requirements for LLC resonant cavity parameter design and broadens the system gain range. In traditional single-stage AC-DC LLC circuits, the LLC resonant cavity must simultaneously perform power factor correction and overall system gain adjustment, leading to significant design challenges for resonant parameters and a limited voltage gain adjustment range. This invention provides voltage gain capability to the system through a pre-amplifier totem-pole PFC circuit, reducing the requirements for LLC resonant cavity parameter design. Simultaneously, through the frequency conversion control of the full-bridge LLC resonant circuit, the switching frequency can be dynamically adjusted according to changes in the bus voltage, thereby achieving precise control of the output voltage and broadening the system's voltage gain range. This invention can adapt to a wider input voltage range and load variations, improving the circuit's adaptability and flexibility. This has significant application value for equipment that needs to operate stably under different power grid conditions (such as solar inverters and electric vehicle chargers). Attached Figure Description

[0028] Figure 1 This is a circuit diagram of a quasi-single-stage AC-DC device according to Embodiment 1 of the present invention.

[0029] Figure 2 This is a control strategy diagram for a quasi-single-stage AC-DC device according to Embodiment 2 of the present invention.

[0030] Figure 3 This is the bus voltage waveform of Embodiment 1 of the present invention.

[0031] Figure 4 This is the inductor current waveform of Embodiment 1 of the present invention.

[0032] Figure 5 This is the LLC resonant current waveform of Embodiment 1 of the present invention.

[0033] Figure 6The driving waveform of the totem pole PFC bridge arm switch in Embodiment 1 of the present invention is shown.

[0034] in:

[0035] Cbus, bus filter capacitor; L, power inductor;

[0036] S1, first switch transistor; S2, second switch transistor; Sg1, third switch transistor; Sg2, fourth switch transistor;

[0037] Co, output filter capacitor; Ro, load resistor; Vo, output voltage;

[0038] Sa1, fifth switch; Sa2, seventh switch; Sa3, sixth switch; Sa4, eighth switch;

[0039] Lr, resonant inductance; Cr, resonant capacitor; Lm, magnetizing inductance; T, transformer;

[0040] S3, the ninth switch; S4, the tenth switch. Detailed Implementation

[0041] To make the technical means, inventive features, objectives, and effects of the invention readily understandable, the invention is further described below with reference to specific illustrations. However, the invention is not limited to the embodiments described below.

[0042] It should be understood that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0043] Example 1:

[0044] like Figure 1 The illustrated quasi-single-stage AC-DC power converter includes: a single-phase AC power supply, a totem-pole PFC circuit, a bus filter capacitor Cbus, a bus, and a full-bridge LLC resonant circuit. Because the circuitry between the preceding and following stages is not decoupled by a large capacitor, yet both stages are controlled simultaneously, it is called a quasi-single-stage AC-DC converter.

[0045] The totem-pole PFC circuit is the pre-amplifier stage of this device. The full-bridge LLC resonant circuit is the post-amplifier stage of this device.

[0046] The totem column PFC circuit comprises a power frequency bridge arm, a high frequency bridge arm and a power inductor L, the power frequency bridge arm and the high frequency bridge arm jointly form a totem column H bridge, and the power inductor L is connected in the high frequency bridge arm midpoint.

[0047] The power frequency bridge arm comprises a first switch tube S1 and a second switch tube S2, and the source of the first switch tube S1 is connected with the drain of the second switch tube S2.

[0048] The high frequency bridge arm comprises a third switch tube Sg1 and a fourth switch tube Sg2, and the source of the third switch tube Sg1 is connected with the drain of the fourth switch tube Sg2.

[0049] The L end of the single-phase alternating current power supply is connected to the source of the first switch tube S1, and the N end of the single-phase alternating current power supply is connected to the source of the third switch tube Sg1 through the power inductor L.

[0050] The bus filter capacitor Cbus is connected in parallel between the totem column PFC circuit and the full-bridge LLC resonant circuit through the bus;

[0051] The bus filter capacitor Cbus is a small-capacitance high-voltage-resistant film capacitor.

[0052] The capacitance value of the bus filter capacitor Cbus is 2.2uf, which can filter out high-frequency ripples above 1kHZ, and is not a large-capacitance electrolytic capacitor used for storing energy and smoothing direct current voltage in the traditional two-stage topology.

[0053] The full-bridge LLC resonant circuit comprises a full-bridge LLC primary bridge arm, and the full-bridge LLC primary bridge arm comprises an LLC bridge arm one and an LLC bridge arm two. The LLC bridge arm one comprises a fifth switch tube Sa1 and a sixth switch tube Sa3, and the source of the fifth switch tube Sa1 is connected with the drain of the sixth switch tube Sa3. The LLC bridge arm two comprises a seventh switch tube Sa2 and an eighth switch tube Sa4, and the source of the seventh switch tube Sa2 is connected with the drain of the eighth switch tube Sa4.

[0054] Hereinafter, the first switch tube S1, the third switch tube Sg1, the fifth switch tube Sa1 and the seventh switch tube Sa2 are collectively referred to as upper tubes, and the second switch tube S2, the fourth switch tube Sg2, the sixth switch tube Sa3 and the eighth switch tube Sa4 are referred to as lower tubes. In the front-stage totem column PFC circuit, the drains of the upper tubes of the two bridge arms of the power frequency bridge arm and the high frequency bridge arm are connected with the bus filter capacitor Cbus and the upper tubes of the two bridge arms of the full-bridge LLC primary side, and the sources of the lower tubes of the two bridge arms of the power frequency bridge arm and the high frequency bridge arm are connected with the bus filter capacitor Cbus and the lower tubes of the two bridge arms of the full-bridge LLC primary side.

[0055] The full-bridge LLC resonant circuit further comprises a resonant inductor Lr, a resonant capacitor Cr and a transformer T, the primary side of the transformer T is connected with the full-bridge LLC primary side bridge arm, and the secondary side of the transformer T comprises two output ends. The turns ratio of the primary side to the secondary side of the transformer T is the ratio of the bus voltage peak value to the output voltage.

[0056] The full-bridge LLC resonant circuit further comprises an excitation inductor Lm connected in parallel with the primary side of the transformer T.

[0057] The source of the seventh switch tube Sa2 and the drain of the sixth switch tube Sa3 are respectively connected to the primary side of the transformer T.

[0058] The full-bridge LLC resonant circuit further comprises a full-wave rectification output circuit, an output filter capacitor Co and a load resistor Ro. The output filter capacitor Co is connected in parallel between the output end of the full-wave rectification circuit and the load resistor Ro. The full-wave rectification output circuit comprises two SiC switch tubes for full-wave rectification of the secondary side of the full-bridge LLC, a ninth switch tube S3 and a tenth switch tube S4. The two output ends of the secondary side of the transformer T are respectively connected to the ninth switch tube S3 and the tenth switch tube S4. One output end of the full-wave rectification circuit is connected to the output filter capacitor Co and the load resistor Ro. Among them, the filter capacitor Co is formed by connecting a plurality of small-capacitance capacitors in parallel, and is connected in parallel to the output end of the load.

[0059] Preferably, the switch tubes in the line frequency bridge arm, the high frequency bridge arm, the LLC bridge arm one and the LLC bridge arm two are selected from SiC switch tubes or GaN tubes.

[0060] Referring to Figure 3 is the bus voltage waveform diagram when the input voltage effective value is 264V, the given output reference voltage is 48V, and the output power is 2000W, referring to Figure 4 is the inductance current waveform diagram through the power inductor L at this time, referring to Figure 5 is the LLC resonant cavity current waveform corresponding thereto, referring to Figure 6 is the totem pole line frequency bridge arm and high frequency bridge arm driving waveform diagram.

[0061] The totem column PFC circuit adopts a totem column structure combining a power frequency bridge arm and a high frequency bridge arm. The power frequency bridge arm is responsible for processing the power frequency variation of the input voltage, and the high frequency bridge arm is used for high frequency switching control. This structure not only retains the processing capability of the PFC circuit on the input voltage in the two-stage topology, but also avoids the use of a large electrolytic capacitor in the traditional two-stage topology. The full-bridge LLC resonant circuit utilizes the high frequency switching characteristics of the LLC resonant circuit to realize efficient DC-DC conversion. The frequency control mode of the LLC resonant circuit can dynamically adjust the switching frequency according to the change of the bus voltage, thereby realizing accurate control of the output voltage. The bus filter capacitor Cbus uses a small value thin film capacitor instead of a large electrolytic capacitor in the traditional two-stage topology. The thin film capacitor has the advantages of small size, high voltage resistance, and good high frequency characteristics, and can effectively filter out high frequency ripples, while avoiding the problems of large size and short service life caused by large electrolytic capacitors.

[0062] Embodiment 2:

[0063] As shown in a control method of a quasi-single-stage AC-DC power conversion device, comprising the following steps: Figure 2

[0064] S1, collect circuit information: obtain the key parameters of the circuit, and provide real-time data for subsequent control.

[0065] Collect the inductance current IL of the power inductor L, the output voltage Vo across the output filter capacitor Co, the bus voltage Vbus across the bus filter capacitor Cbus, and the phase information PH of the single-phase alternating current power supply;

[0066] S2, adjust the voltage: adjust the output voltage through a PI regulator to ensure that the output voltage is stable at the preset value.

[0067] Subtract the output voltage Vo from the preset reference voltage Vref to obtain a calculation result Verror; adjust the calculation result Verror through a proportional integral regulator (PI regulator) and then perform amplitude limiting processing to obtain a voltage modulation signal Vc;

[0068] The incremental PI regulator expression used in this embodiment is as follows:

[0069] Voerr0=Verror

[0070] Uk=Uk+Kp1*(Voerr0-Voerr1)+Ki1*Voerr0

[0071] Voerr1=Voerr0

[0072] Vc=Uk

[0073] ​Wherein, Voerr0, Uk, Voerr1 are intermediate variables, Kp1, Ki1 are proportional and integral coefficients respectively.

[0074] The voltage limiting expression is as follows:

[0075]

[0076] The limiting value is set according to the maximum power allowed, and the effective value of the current when the input voltage is effectively 264V.

[0077] S3, generating a current reference signal: generating a sinusoidal current reference signal matching the phase of the input voltage, for controlling the inductor current, realizing power factor correction.

[0078] The voltage modulation signal Vc is multiplied by the phase sine value Sin(PH) of the single-phase alternating current power supply to obtain a sinusoidal current reference signal Iref matching the phase of the input voltage of the single-phase alternating current power supply; the sinusoidal current reference signal Iref is subtracted from the inductor current IL to obtain a calculation result two Ierror; the calculation result two Ierror is adjusted by a proportional resonant regulator (PR regulator) to obtain a current modulation signal Ic;

[0079] In the present example, the PR regulator realizes zero-error tracking of the input current to the given power frequency current reference signal by digital filtering, and the expression is as follows:

[0080] PR_ic=Kpr*0.0006279178*ierror-Kpr*0.0006279178*PR_ierror 2

[0081] +1.9987047*PR_ic1-0.99874416*PR_ic2

[0082] PR_ierror 2=PR_ierror 1

[0083] PR_ierror 1=Ierror

[0084] PR_ic2=PR_ic1

[0085] PR_ic1=PR_ic

[0086] ikc=ierror*Kr

[0087] Ic=PR_ic+ikc

[0088] Wherein, the digital filter used is a second-order band-pass filter with a center frequency of 50 Hz and a bandwidth range of 10 Hz, PR_ic, PR_ierror1, PR_ierror2, PR_ic1, PR_ic2 are intermediate variables, and Kr and Kpr are proportional and resonant coefficients, respectively.

[0089] S4, control the high-frequency bridge arm switch: according to the current modulation signal Ic control high-frequency bridge arm switch tube, realize high-frequency switch control, ensure that the output voltage reaches the preset value.

[0090] The current modulation signal Ic is compared with the high-frequency triangular carrier Vs1 to obtain the high-frequency bridge arm switch tube drive signal Vg1 and Vg2; the output voltage Vo is controlled to reach the preset reference voltage Vref according to the high-frequency bridge arm switch tube drive signal Vg1 and Vg2; the high-frequency triangular carrier Vs1 has a fixed frequency and is used for comparison with the current modulation signal Ic to change the duty cycle of the switch tube drive signals Vg1 and Vg2.

[0091] S5, control the high-frequency bridge arm switch: according to the phase information of the input voltage, control the switch tube of the high-frequency bridge arm, realize the high-frequency switch control.

[0092] According to the phase information PH, the input voltage phase and the square wave signal with the same phase as the input voltage phase are obtained; the square wave signal is used to drive the high-frequency bridge arm, and in the positive half cycle of the input voltage, the first switch tube S1 is always on and the second switch tube S2 is off; in the negative half cycle of the input voltage, the second switch tube S2 is always on and the first switch tube S1 is off;

[0093] S6, control the full-bridge LLC resonant circuit frequency conversion: through frequency conversion control, adjust the switching frequency of the LLC resonant circuit to realize dynamic adjustment of the bus voltage.

[0094] The full-bridge LLC modulation signal Vc_llc is obtained by looking up the lookup table according to the bus voltage Vbus using the lookup table method, and the direct current bias value and the amplitude of the modulation signal are related to the first resonant frequency and the second resonant frequency obtained through resonant cavity design. The period of the triangular carrier Vs2 is adjusted through Vc_llc to control the switching frequency of the fifth switch tube Sa1, the seventh switch tube Sa2, the sixth switch tube Sa3, and the eighth switch tube Sa4, thereby realizing frequency conversion control of the LLC and controlling the bus voltage Vbus to maintain continuous half-wave form and voltage peak value. The period of the triangular carrier Vs2 changes with Vc_llc, so its frequency is variable, and the duty cycle is fixed, which affects the switching frequency of the fifth switch tube Sa1, the seventh switch tube Sa2, the sixth switch tube Sa3, and the eighth switch tube Sa4.

Claims

1. A quasi-single-stage AC-DC power conversion apparatus, characterized by, The single-phase alternating current power supply, the totem pole PFC circuit, the bus filter capacitor (Cbus), the bus, and the full-bridge LLC resonant circuit are included. The totem pole PFC circuit includes a power frequency bridge arm, a high-frequency bridge arm, and a power inductor (L). The power frequency bridge arm includes a first switch tube (S1) and a second switch tube (S2), and the source of the first switch tube (S1) is connected to the drain of the second switch tube (S2). The high-frequency bridge arm includes a third switch tube (Sg1) and a fourth switch tube (Sg2), and the source of the third switch tube (Sg1) is connected to the drain of the fourth switch tube (Sg2). The L terminal of the single-phase alternating current power supply is connected to the source of the first switch tube (S1). The N terminal of the single-phase alternating current power supply is connected to the source of the third switch tube (Sg1) through the power inductor (L). The bus filter capacitor (Cbus) is connected in parallel between the totem pole PFC circuit and the full-bridge LLC resonant circuit through the bus. The bus filter capacitor (Cbus) is a film capacitor. The capacitance of the bus filter capacitor (Cbus) is 2.2uf.

2. The quasi-single-stage AC-DC power conversion device of claim 1, wherein, The full-bridge LLC resonant circuit includes a full-wave rectification output circuit, an output filter capacitor (Co), and a load resistor (Ro), and the output filter capacitor (Co) is connected in parallel between the output terminal of the full-wave rectification output circuit and the load resistor (Ro).

3. The quasi-single-stage AC-DC power conversion device of claim 1, wherein: The steps include:

4. The control method of a quasi-single-stage AC-DC power conversion device according to claim 3, characterized by, S1, collecting the inductance current (IL) of the power inductor (L), the output voltage (Vo) between the output filter capacitor (Co), the bus voltage (Vbus) between the bus filter capacitor (Cbus), and the phase information (PH) of the single-phase alternating current power supply; S2, subtracting the output voltage (Vo) from the preset reference voltage (Vref) to obtain a calculation result one (Verror), and then adjusting the calculation result one (Verror) through a proportional integral regulator and performing amplitude limiting processing to obtain a voltage modulation signal (Vc); S3, multiplying the voltage modulation signal (Vc) by the phase sine value (Sin(PH)) of the single-phase alternating current power supply to obtain a sine current reference signal (Iref) matched with the input voltage phase of the single-phase alternating current power supply, and then subtracting the sine current reference signal (Iref) from the inductance current (IL) to obtain a calculation result two (Ierror); adjusting the calculation result two (Ierror) through a proportional resonant regulator to obtain a current modulation signal (Ic); S4, comparing the current modulation signal (Ic) with a high-frequency triangular carrier (Vs1) to obtain a high-frequency bridge arm switch tube driving signal, and controlling the output voltage (Vo) to reach the preset reference voltage (Vref) according to the high-frequency bridge arm switch tube driving signal. ​ S5, obtaining an input voltage phase and a square wave signal in phase with the input voltage phase according to the phase information (PH); driving the power frequency bridge arm according to the square wave signal, driving the first switch tube (S1) to be always on and the second switch tube (S2) to be off in a positive half cycle of the input voltage; and driving the second switch tube (S2) to be always on and the first switch tube (S1) to be off in a negative half cycle of the input voltage; S6, obtaining a full-bridge LLC modulation signal (Vc_llc) by looking up a lookup table according to the bus voltage (Vbus) and realizing frequency conversion control on the full-bridge LLC resonant circuit through the full-bridge LLC modulation signal (Vc_llc).

5. The control method according to claim 4, characterized by The phase information (PH) is collected by a zero-crossing phase-locked loop (PLL) method.

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