Single-stage isolated bidirectional AC-DC converter and control method thereof

Abstract

The invention discloses a single-stage isolated bidirectional AC-DC converter and a control method thereof, and belongs to the technical field of power electronic converters, the single-stage isolated bidirectional AC-DC converter comprises a primary side conversion module, a voltage transformation module and a secondary side conversion module, and the primary side conversion module, the voltage transformation module and the secondary side conversion module are connected in sequence. The single-stage isolation type bidirectional AC-DC converter provided by the invention has the advantages of smaller conduction loss, lower cost and higher power density.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic converters, and in particular to a single-stage isolated bidirectional AC-DC converter and a control method thereof. Background Art

[0002] With the vigorous development and application of new energy power generation technology, electric vehicle technology and energy storage technology, isolated bidirectional AC-DC converters, as core equipment, have gradually become a research hotspot. As a power electronic converter, efficiency, reliability and power density are important indicators to measure its performance.

[0003] Isolated bidirectional AC-DC converters can be divided into two-stage and single-stage structures according to the number of power conversion stages. The two-stage structure usually consists of a non-isolated AC-DC conversion link, a DC bus, and a high-frequency isolated DC-DC conversion link. This type of structure requires the addition of a larger electrolytic capacitor to the DC bus, which not only increases the volume of the system, but also reduces the service life of the entire converter due to the relatively short life of the electrolytic capacitor. On the other hand, since the two-stage structure requires two power conversion links, there are more switching devices, the system loss will increase, and the efficiency improvement is limited.

[0004] In order to improve the efficiency, life and power density of bidirectional AC-DC converters, the single-stage structure has received extensive attention and research in recent years. At present, there are two common single-stage AC-DC converter structures, one is a single-stage AC-DC converter based on a matrix converter, and the other is a single-stage AC-DC converter based on an unfolding circuit. Although the single-stage AC-DC converter based on the matrix converter can directly realize the AC-DC link, it requires a switch with bidirectional blocking capability, which not only increases the difficulty of control, but also increases the conduction loss and system cost. Although the single-stage AC-DC converter based on the unfolding circuit does not need to use a bidirectional switch, due to the existence of the unfolding circuit, the total number of switch devices of the converter has not been reduced, and there are also problems such as large conduction loss, high cost and low power density. Summary of the invention

[0005] In order to solve the above problems, the present invention aims to provide a single-stage isolated bidirectional AC-DC converter and a control method thereof, wherein the single-stage isolated bidirectional AC-DC converter is obtained by multiplexing the bridge arms of a non-isolated totem pole PFC converter and an isolated half-bridge DC-DC converter, that is, the high-frequency bridge arm of the totem pole PFC is multiplexed with the primary half-bridge of the isolated half-bridge DC-DC converter, thereby reducing the number of switching devices and eliminating the DC bus and the large-capacitance electrolytic capacitor thereon. Therefore, the single-stage isolated bidirectional AC-DC converter of the present invention has smaller conduction loss, lower cost and higher power density; in addition, it also has power factor correction and bidirectional power transmission capabilities.

[0006] To achieve the above object, the technical solution of the present invention is: A single-stage isolated bidirectional AC-DC converter comprises a primary side conversion module, a voltage transformation module and a secondary side conversion module, wherein the primary side conversion module, the voltage transformation module and the secondary side conversion module are connected in sequence; The primary side conversion module includes an industrial frequency bridge arm, a high frequency bridge arm, a first capacitor, a second capacitor, a first inductor and a second inductor. The two ends of the industrial frequency bridge arm, the two ends of the high frequency bridge arm, and the two ends of the first capacitor are connected in parallel. The midpoint of the industrial frequency bridge arm is connected to the first end of the AC voltage through the first inductor. The midpoint of the high frequency bridge arm is connected to the second end of the AC voltage. The midpoint of the high frequency bridge arm, the second capacitor, the second inductor, the primary winding of the transformer module, the first capacitor and the connection point of the lower bridge arm of the high frequency bridge arm are connected in sequence.

[0007] Furthermore, the above-mentioned industrial frequency bridge arm includes a first switch and a second switch, and the first switch and the second switch are connected in series in the same direction.

[0008] Furthermore, the high-frequency bridge arm comprises a third switch and a fourth switch, and the third switch and the fourth switch are connected in series in the same direction.

[0009] In a specific embodiment, the secondary side conversion module includes a rectifier topology.

[0010] In a specific embodiment, the above-mentioned secondary side conversion module includes a first secondary side bridge arm and a second secondary side bridge arm, the two ends of the first secondary side bridge arm and the two ends of the second secondary side bridge arm are connected in parallel, the midpoint of the first secondary side bridge arm is connected to the first end of the secondary winding of the transformer module, the midpoint of the second secondary side bridge arm is connected to the second end of the secondary winding of the transformer module, and the two ends of the first secondary side bridge arm and the two ends of the second secondary side bridge arm are connected in parallel with a DC voltage.

[0011] The present invention also provides a control method for a single-stage isolated bidirectional AC-DC converter, which uses the above-mentioned single-stage isolated bidirectional AC-DC converter, including: when the AC voltage is greater than 0, controlling the switch of the upper bridge arm of the industrial frequency bridge arm to be normally on, the switch of the lower bridge arm of the industrial frequency bridge arm to be normally off, and the switch of the upper bridge arm of the high-frequency bridge arm and the switch of the lower bridge arm to be complementary to each other; when the AC voltage is less than 0, controlling the switch of the upper bridge arm of the industrial frequency bridge arm to be normally off, the switch of the lower bridge arm of the industrial frequency bridge arm to be normally on, and the switch of the upper bridge arm of the high-frequency bridge arm and the switch of the lower bridge arm to be complementary to each other.

[0012] Furthermore, the control method of the single-stage isolated bidirectional AC-DC converter further includes controlling the two switches in the same secondary bridge arm in the secondary conversion module to be complementary turned on and the different secondary bridge arms to be phase-shifted turned on.

[0013] Furthermore, the control method of the single-stage isolated bidirectional AC-DC converter also includes adjusting the transmission power of the single-stage isolated bidirectional AC-DC converter by controlling the internal phase shift angle of the secondary side conversion module and the phase shift angle between the primary and secondary side bridges.

[0014] Furthermore, the operating frequency of the industrial frequency bridge arm is consistent with the frequency of the AC voltage, and the operating frequency of the switch in the high-frequency bridge arm is the same as the operating frequency of the switch in the secondary side conversion module.

[0015] Furthermore, the control method of the single-stage isolated bidirectional AC-DC converter further includes controlling the single-stage isolated bidirectional AC-DC converter to operate in an inductor current continuous mode.

[0016] Beneficial effects: The present invention provides a single-stage isolated bidirectional AC-DC converter and a control method thereof, which reduces the number of switching devices by multiplexing bridge arms, reduces the number of switches through which current flows, reduces the conduction loss and turn-off loss of the switching devices, and reduces the cost of the converter; realizes single-stage power conversion from AC to DC, improves the efficiency of the converter, and realizes power factor correction and high-frequency electrical isolation at the same time; eliminates the intermediate DC bus and the large-capacitance electrolytic capacitors for voltage regulation thereon, reduces the size of the converter to a certain extent, and has a higher power density; the high-frequency switching devices on the primary side of the transformer are complementary-conducted with a fixed duty cycle, and there is no sudden change in the duty cycle, and the problem of input current zero-crossing spikes is effectively suppressed; phase-shift control is adopted, and it has the characteristics of a dual active bridge converter, has a strong wide voltage working capability, and can perform bidirectional power transmission.

[0017] In order to make the above features and advantages of the invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a circuit diagram of a single-stage isolated bidirectional AC-DC converter.

[0019] Figure 2 for Figure 1 When the AC voltage in the circuit is greater than 0, the voltage V AB , voltage V pri , voltage V CD 、Current I Ls Simplified waveform diagram during one switching cycle.

[0020] Figure 3 for Figure 1 Simulation waveform of key voltage and current in the circuit over time t.

[0021] Figure 4 for Figure 3 A magnified view of the simulation waveform.

[0022] Figure 5 0.1 times the AC voltage V g With AC current I g Waveform diagram of . DETAILED DESCRIPTION

[0023] In order to make the purpose and technical solution of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Figure 1 FIG. 1 is a circuit diagram of a single-stage isolated bidirectional AC-DC converter of the present invention. Figure 1 As shown, the present invention is a single-stage isolated bidirectional AC-DC converter comprising a primary side conversion module 1, a transformer module 2 and a secondary side conversion module 3, and an AC voltage V g , the primary side conversion module 1, the voltage transformation module 2, the secondary side conversion module 3, the DC voltage V o Connect in sequence.

[0025] Furthermore, the primary side conversion module 1 includes an industrial frequency bridge arm 11, a high frequency bridge arm 12, a capacitor C f , capacitor C b 、Inductance L g With inductance L s The two ends of the power frequency bridge arm 11, the two ends of the high frequency bridge arm 12, and the capacitor C f The two ends are connected in parallel, and the midpoint of the bridge arm of the power frequency bridge arm 11 passes through the inductor Lg Connect AC voltage V g The first end of the high-frequency bridge arm 12 is connected to an AC voltage V g The second end of the high frequency bridge arm 12, the midpoint of the bridge arm, the capacitor C b , the inductor L s , the primary winding of the transformer module 2, the capacitor C f The connection points with the lower bridge arm of the high-frequency bridge arm 12 are connected in sequence.

[0026] Furthermore, the industrial frequency bridge arm 11 includes a switch S1 and a switch S2, and the switch S1 and the switch S2 are connected in series in the same direction.

[0027] Furthermore, the high-frequency bridge arm 12 includes a switch S3 and a switch S4, and the switch S3 and the switch S4 are connected in series in the same direction.

[0028] Furthermore, the secondary side conversion module 3 includes a rectification topology.

[0029] Optionally, the secondary side conversion module 3 includes a full-bridge rectifier topology, specifically including a first secondary side bridge arm 31 and a second secondary side bridge arm 32, the two ends of the first secondary side bridge arm 31 and the two ends of the second secondary side bridge arm 32 are connected in parallel, the midpoint of the first secondary side bridge arm 31 is connected to the first end of the secondary winding of the transformer module 2, the midpoint of the second secondary side bridge arm 32 is connected to the second end of the secondary winding of the transformer module 2, and the two ends of the first secondary side bridge arm 31 and the two ends of the second secondary side bridge arm 32 are connected in parallel with a DC voltage V o .

[0030] Furthermore, the first secondary bridge arm 31 includes a switch S5 and a switch S6, and the switch S5 and the switch S6 are connected in series in the same direction.

[0031] Furthermore, the second secondary bridge arm 32 includes a switch S7 and a switch S8, and the switch S7 and the switch S8 are connected in series in the same direction.

[0032] Furthermore, the transformer module 2 includes a transformer T r , the transformer T r The two ends of the primary winding are connected to the inductor L s , the capacitor C f The connection point with the lower bridge arm of the high frequency bridge arm 12; the transformer T r Two ends of the secondary winding are respectively connected to the midpoint of the first secondary bridge arm 31 and the midpoint of the second secondary bridge arm 32 .

[0033] Among them, the transformer T r The turns ratio is n.

[0034] Furthermore, the single-stage isolated bidirectional AC-DC converter of the present invention further includes a capacitor C o , the capacitor C o Connected in parallel with DC voltage V o The capacitor C o It acts as a filter.

[0035] More specifically, the capacitor C f It is used for high frequency filtering; the capacitor C b The inductor L g It plays the role of current filtering and voltage boosting; the inductor L s It plays the role of power transmission.

[0036] Optionally, the switch S1, the switch S2, the switch S3, the switch S4, the switch S5, the switch S6, the switch S7, and the switch S8 are semiconductor devices that can be used as switch tubes, such as IGBT, MOSFET, and triode, but the present invention is not limited thereto.

[0037] More specifically, the single-stage isolated bidirectional AC-DC converter of the present invention can realize bidirectional power transmission, that is, it can convert the AC voltage V g Converted into DC voltage V o , it is also possible to convert the DC voltage V o Converted into AC voltage V g .

[0038] Please continue to refer to Figure 1 For the convenience of the following description, the midpoint of the high-frequency bridge arm 12 is defined as point A, and the capacitor C f The connection point with the lower bridge arm of the high-frequency bridge arm 12 is defined as point B, and the voltage V AB is the voltage between points A and B; voltage V pri The capacitance C b With the inductance L s The midpoint of the bridge arm of the first secondary bridge arm 31 is defined as point C, and the midpoint of the bridge arm of the second secondary bridge arm 32 is defined as point D, and the voltage V CD is the voltage between points C and D, voltage V CD It is the high frequency voltage on the secondary side of the transformer module.

[0039] The present invention also provides a control method for a single-stage isolated bidirectional AC-DC converter, comprising: when the AC voltage V g When it is greater than 0, the switch of the upper bridge arm of the power frequency bridge arm 11 is normally on, the switch of the lower bridge arm of the power frequency bridge arm 11 is normally off, and the switch of the upper bridge arm of the high frequency bridge arm 12 is complementary to the switch of the lower bridge arm; when the AC voltage V gWhen V is less than 0, the switch of the upper bridge arm of the power frequency bridge arm 11 is normally off, the switch of the lower bridge arm of the power frequency bridge arm 11 is normally on, and the switch of the upper bridge arm of the high frequency bridge arm 12 is complementary to the switch of the lower bridge arm. Specifically, when the AC voltage V g When the AC voltage V g When it is less than 0, the control switch S1 is normally off, the switch S2 is normally on, and the switch S3 and the switch S4 are complementarily turned on.

[0040] Optionally, the operating frequency of the industrial frequency bridge arm 11 is consistent with the frequency of the AC voltage Vg.

[0041] Optionally, the duty cycle of the switch S3 and the switch S4 is fifty percent.

[0042] More specifically, within half a power frequency cycle, the power frequency bridge arm 11 and the high frequency bridge arm 12 can be equivalent to a Boost circuit. Therefore, the voltage waveform across the capacitor Cf is a steamed bun wave with a peak value twice the peak value of Vg.

[0043] The present invention provides a control method for a single-stage isolated bidirectional AC-DC converter, further comprising: controlling the two switches of the same secondary bridge arm in the secondary conversion module 3 to be complementary turned on, that is, switch S5 and switch S6 are complementary turned on, and switch S7 and switch S8 are complementary turned on; different secondary bridge arms are phase-shifted turned on, specifically, the drive signal phase difference between switch S5 and switch S8 is The driving signals of switch S6 and switch S7 also differ ,in, is the internal phase shift angle of the secondary side conversion module.

[0044] Optionally, the operating frequency of the switches in the high-frequency bridge arm 12 is the same as the operating frequency of the switches in the secondary side conversion module 3 .

[0045] Among them, by controlling the internal phase shift angle of the secondary side conversion module The change of can make the voltage VCD between points C and D a three-level voltage.

[0046] The present invention provides a control method for a single-stage isolated bidirectional AC-DC converter, further comprising: controlling the internal phase shift angle of the secondary side conversion module , the phase shift angle between the original and secondary bridges , adjust the transmission power of the single-stage isolated bidirectional AC-DC converter. is the phase shift angle between the primary high-frequency bridge arm 12 and the secondary first bridge arm 31 .

[0047] Optionally, a single-stage isolated bidirectional AC-DC converter of the present invention is controlled to operate in an inductor current continuous mode.

[0048] The following takes the rectification mode as an example to introduce the working principle of the present invention. g When it is greater than 0, switch S1 is always on, switch S2 is always off, and switch S3 and switch S4 are turned on at high frequency. When switch S3 is turned on and switch S4 is turned off, the inductor L g In charging state, voltage V AB Equal to capacitance C f Voltage across both ends; when switch S4 is turned on and switch S3 is turned off, the inductor L g In the discharge state, the voltage V AB is 0.

[0049] When the AC voltage V g When it is less than 0, switch S2 is always on, switch S1 is always off, and switch S3 and switch S4 are turned on at high frequency. When switch S3 is turned on and switch S4 is turned off, the inductor L g In the discharge state, the voltage V AB Equal to capacitance C f Voltage across both ends; when switch S4 is turned on and switch S3 is turned off, the inductor L g In charging state, voltage V AB is 0.

[0050] Therefore, the voltage V AB The waveform is a high-frequency square wave with a steamed-bun wave envelope. The voltage V AB Through capacitor C b After isolating the DC voltage, we get pri , voltage V pri is a high-frequency square wave with a sinusoidal envelope. When the switches S5 and S8 on the secondary side are turned on at the same time, the voltage V CD Equal to voltage V o ; When the switches S5 and S7 on the secondary side are turned on at the same time, the voltage V CD =0; when the switches S6 and S7 on the secondary side are turned on at the same time, the voltage V CD Equal to -V o ; When the switches S6 and S8 on the secondary side are turned on at the same time, the voltage V CD =0, thus realizing the voltage V between points C and D CD It is a three-level voltage.

[0051] Figure 2 for Figure 1 The simplified waveform diagram of the voltage VAB, voltage Vpri, voltage VCD, and current ILs in the circuit in one switching cycle when the AC voltage is greater than 0, where: is the original secondary bridge phase shift angle, Let $\theta$ be the internal phase-shift angle of the secondary-side conversion module, and $I_{Ls}$ be the current flowing through inductor $L_s$. When the single-stage isolated bidirectional AC-DC converter operates in Stage 1 ($t_0 < t < t_1$), switches $S1$, $S3$, $S6$, and $S7$ are turned on, and the remaining switches are turned off. At this time, voltage $V_{AB}$ is equal to the voltage across capacitor $C_f$, voltage $V_{CD}$ is equal to $-V_o$, inductor $L_g$ is in the charging state, and current $I_{Ls}$ rises linearly. When the single-stage isolated bidirectional AC-DC converter operates in Stage 2 ($t_1 < t < t_2$), switches $S1$, $S3$, $S5$, and $S7$ are turned on, and the remaining switches are turned off. At this time, voltage $V_{AB}$ is still equal to the voltage across capacitor $C_f$, voltage $V_{CD}$ changes from $-V_o$ to $0$, inductor $L_g$ is in the charging state, and current $I_{Ls}$ rises linearly. When the single-stage isolated bidirectional AC-DC converter operates in Stage 3 ($t_2 < t < t_3$), switches $S1$, $S3$, $S5$, and $S8$ are turned on, and the remaining switches are turned off. At this time, voltage $V_{AB}$ is still equal to the voltage across capacitor $C_f$, voltage $V_{CD}$ changes from $0$ to $V_o$, inductor $L_g$ is in the charging state, and current $I_{Ls}$ continues to rise linearly, but the rising speed slows down. When the single-stage isolated bidirectional AC-DC converter operates in Stage 4 ($t_3 < t < t_4$), switches $S1$, $S4$, $S5$, and $S8$ are turned on, and the remaining switches are turned off. At this time, voltage $V_{AB}$ becomes $0$, voltage $V_{CD}$ remains $V_o$, inductor $L_g$ starts to enter the discharging state, and current $I_{Ls}$ starts to decline linearly. When the single-stage isolated bidirectional AC-DC converter operates in Stage 5 ($t_4 < t < t_5$), switches $S1$, $S4$, $S6$, and $S8$ are turned on, and the remaining switches are turned off. At this time, voltage $V_{AB}$ remains $0$, voltage $V_{CD}$ is $0$, inductor $L_g$ continues to discharge, and current $I_{Ls}$ continues to decline linearly. When the single-stage isolated bidirectional AC-DC converter operates in Stage 6 ($t_5 < t < t_6$), switches $S1$, $S4$, $S6$, and $S7$ are turned on, and the remaining switches are turned off. At this time, voltage $V_{AB}$ remains $0$, voltage $V_{CD}$ changes to $-V_o$, inductor $L_g$ continues to discharge, and current $I_{Ls}$ continues to decline linearly. After $t_6$, the next switching cycle begins.

[0052] To verify the feasibility of the single-stage isolated bidirectional AC-DC converter and its control method proposed in the present invention, experimental verification was carried out on a simulation platform. The parameters of the simulation prototype are as follows: the AC voltage $V_g$ is 220V (50Hz), the DC voltage $V_o$ is 400V, the rated power is 1kW, and the switching frequency is 100kHz. Among them, the turns ratio of transformer $Tr$ is 1:1, the inductance of inductor $L_s$ is 30 , the capacitance of capacitor $C_b$ is 2 , and the inductance of inductor $L_g$ is 1mH. When the single-stage isolated bidirectional AC-DC converter operates stably, the key voltage and current waveforms are as Figure 3 , Figure 4 , Figure 5 As shown. Among them, Figure 5 The waveform diagram of the AC voltage Vg and AC current Ig is 0.1 times. Figure 5 It can be seen that there is substantially no phase difference between the AC voltage Vg and the AC current Ig, and the single-stage isolated bidirectional AC-DC converter of the present invention can achieve power factor correction.

[0053] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person having ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims

1. A single-stage isolated bidirectional AC-DC converter, characterized in that: It includes a primary side conversion module, a voltage transformation module and a secondary side conversion module, wherein the primary side conversion module, the voltage transformation module and the secondary side conversion module are connected in sequence; The primary side conversion module includes an industrial frequency bridge arm, a high frequency bridge arm, a first capacitor, a second capacitor, a first inductor and a second inductor. The two ends of the industrial frequency bridge arm, the two ends of the high frequency bridge arm, and the two ends of the first capacitor are connected in parallel. The midpoint of the industrial frequency bridge arm is connected to the first end of the AC voltage through the first inductor. The midpoint of the high frequency bridge arm is connected to the second end of the AC voltage. The midpoint of the high frequency bridge arm, the second capacitor, the second inductor, the primary winding of the transformer module, the first capacitor and the connection point of the lower bridge arm of the high frequency bridge arm are connected in sequence.

2. A single-stage isolated bidirectional AC-DC converter as claimed in claim 1, characterized in that: The industrial frequency bridge arm includes a first switch and a second switch, and the first switch and the second switch are connected in series in the same direction.

3. A single-stage isolated bidirectional AC-DC converter as claimed in claim 2, characterized in that: The high-frequency bridge arm includes a third switch and a fourth switch, and the third switch and the fourth switch are connected in series in the same direction.

4. A single-stage isolated bidirectional AC-DC converter as claimed in claim 1, characterized in that: The secondary side conversion module includes a rectification topology.

5. A single-stage isolated bidirectional AC-DC converter as claimed in claim 4, characterized in that: The secondary side conversion module includes a first secondary side bridge arm and a second secondary side bridge arm, the two ends of the first secondary side bridge arm and the two ends of the second secondary side bridge arm are connected in parallel, the midpoint of the first secondary side bridge arm is connected to the first end of the secondary winding of the transformer module, the midpoint of the second secondary side bridge arm is connected to the second end of the secondary winding of the transformer module, and the two ends of the first secondary side bridge arm and the two ends of the second secondary side bridge arm are connected in parallel with a DC voltage.

6. A control method for a single-stage isolated bidirectional AC-DC converter, characterized in that: A single-stage isolated bidirectional AC-DC converter as described in any one of claims 1 to 5, comprising: when the AC voltage is greater than 0, controlling the switch of the upper bridge arm of the industrial frequency bridge arm to be normally on, the switch of the lower bridge arm of the industrial frequency bridge arm to be normally off, and the switch of the upper bridge arm of the high-frequency bridge arm and the switch of the lower bridge arm to be complementary to each other; when the AC voltage is less than 0, controlling the switch of the upper bridge arm of the industrial frequency bridge arm to be normally off, the switch of the lower bridge arm of the industrial frequency bridge arm to be normally on, and the switch of the upper bridge arm of the high-frequency bridge arm and the switch of the lower bridge arm to be complementary to each other.

7. A control method for a single-stage isolated bidirectional AC-DC converter as claimed in claim 6, characterized in that: It also includes controlling the secondary side conversion module so that two switches in the same secondary side bridge arm are complementary turned on and different secondary side bridge arms are turned on in a phase-shifted manner.

8. A control method for a single-stage isolated bidirectional AC-DC converter as claimed in claim 7, characterized in that: The invention also includes adjusting the transmission power of the single-stage isolated bidirectional AC-DC converter by controlling the internal phase shift angle of the secondary side conversion module and the phase shift angle between the primary and secondary side bridges.

9. A control method for a single-stage isolated bidirectional AC-DC converter as claimed in claim 7, characterized in that: The operating frequency of the industrial frequency bridge arm is consistent with the frequency of the AC voltage, and the operating frequency of the switch in the high-frequency bridge arm is the same as the operating frequency of the switch in the secondary side conversion module.

10. A control method for a single-stage isolated bidirectional AC-DC converter as claimed in claim 6, characterized in that: The method also includes controlling the single-stage isolated bidirectional AC-DC converter to operate in an inductor current continuous mode.

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