Single-phase full-bridge PFC control circuit and control method thereof, charging and discharging device and vehicle

Abstract

The invention discloses a single-phase full-bridge PFC control circuit, a control method thereof, a charging and discharging device and a vehicle, and the circuit comprises an AC power supply which is used for providing AC; one end of the inductor is connected with the first output end of the alternating-current power supply; one end of the first capacitor is connected with the first output end of the alternating current power supply; one end of the second capacitor is connected with the other end of the first capacitor, the first capacitor is connected with the load in parallel, and the sum of capacitance values of the first capacitor and the second capacitor is smaller than a preset capacitance value; and the switch bridge arm unit is respectively connected with the other end of the inductor, the other end of the first capacitor and the second capacitor. According to the invention, secondary pulsating power can be absorbed by adding the first capacitor, so that the burden of the second capacitor in suppressing voltage fluctuation is effectively reduced, an efficient power factor correction function is realized, the circuit structure is simplified, the cost is reduced, and the stability and reliability of the control circuit are improved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a single-phase full-bridge PFC control circuit and a control method thereof, a charging and discharging device, and a vehicle. Background Art

[0002] Although the DC current method has been applied to single-phase full-bridge PFC (Power Factor Correction) circuits, it performs poorly in controlling the AC capacitor current in the improved circuit. Another approach employs a dual closed-loop control strategy with an outer voltage loop and an inner current loop. By using nonlinear active disturbance rejection control technology in the outer voltage loop and single-phase direct-quadrature (DQ) current decoupling control in the inner current loop, this ensures stable operation with unity power factor on the grid side and stable control of the DC voltage.

[0003] In addition, there is technology that uses a three-phase power converter to achieve multifunctional integration of motor drive and traction battery charging to complete efficient power conversion and battery management, and realizes flexible switching of four working modes through three relay switches, thereby improving the system integration.

[0004] However, these methods not only increase hardware costs, resulting in larger size and higher manufacturing costs, but may also increase the complexity of system design and maintenance. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0006] To this end, one object of the present invention is to propose a single-phase full-bridge PFC control circuit, which can absorb secondary pulsating power by adding a first capacitor, thereby effectively reducing the burden of the second capacitor on the DC side in suppressing voltage fluctuations. The demand for the second capacitor is also reduced accordingly, so that the sum of the two is less than the preset capacitance value. At the same time, an efficient power factor correction function is achieved, the dependence on large-capacity capacitors is reduced, and the number of required switching tubes is significantly reduced. This not only reduces the energy loss caused by switching action, but also simplifies the circuit structure, while reducing costs and improving the stability and reliability of the control circuit.

[0007] Therefore, a second object of the present invention is to provide a control method for a single-phase full-bridge PFC control circuit.

[0008] Therefore, the third object of the present invention is to provide a charging and discharging device.

[0009] To this end, a third object of the present invention is to provide a vehicle.

[0010] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present invention discloses a single-phase full-bridge PFC control circuit, comprising: an AC power supply for providing AC power; an inductor, one end of the inductor being connected to a first output end of the AC power supply; a first capacitor, one end of the first capacitor being connected to the first output end of the AC power supply; a second capacitor, one end of the second capacitor being connected to the other end of the first capacitor, the second capacitor being connected in parallel with a load, and the sum of the capacitances of the first capacitor and the second capacitor being less than a preset capacitance value; and a switch bridge arm unit, the switch bridge arm unit being respectively connected to the other end of the inductor, the other end of the first capacitor, and the second capacitor.

[0011] According to an embodiment of the present invention, a single-phase full-bridge PFC control circuit comprises an inductor connected to a first input terminal of an AC power supply, which can provide AC power to the inductor. A first capacitor is also connected to the first input terminal of the AC power supply, and similarly, the AC power supply can provide corresponding AC power to the first capacitor. The other end of the first capacitor is connected to the other end of the second capacitor, and the first capacitor is connected in parallel with the load, forming a stable DC voltage supply structure. This allows the second capacitor to absorb high-frequency ripple generated during switching, ensuring the stability and smoothness of the DC voltage output. Furthermore, because the first capacitor can absorb secondary pulsating power, the burden of suppressing voltage fluctuations on the second capacitor on the DC side is effectively reduced, thereby reducing the demand for the second capacitor, so that the sum of the two capacitors is less than a preset capacitance value, thereby achieving an overall reduction in size and cost.

[0012] The switching bridge arm unit is respectively connected to the other end of the inductor, the other end of the first capacitor, and the second capacitor. By controlling the energy transmission and conversion between these components, efficient power factor correction function is achieved, while reducing dependence on large-capacity capacitors and significantly reducing the number of required switching tubes. It not only reduces the energy loss caused by switching action, but also simplifies the circuit structure, reduces costs, and improves the stability and reliability of the control circuit.

[0013] In addition, the single-phase full-bridge PFC control circuit according to the above embodiment of the present invention may also have the following additional technical features: In some embodiments, the single-phase full-bridge PFC control circuit further includes a control unit connected to the switch arm unit and configured to control a first current output from the second output terminal of the AC power supply and a second current flowing through the inductor by controlling the on / off state of the switch arm unit, thereby controlling a third current flowing through the first capacitor based on the first and second currents. This ensures that the AC input current is a sinusoidal wave with a unity power factor, completely absorbing the secondary pulsating power. This not only optimizes the input current waveform and reduces harmonic distortion, but also ensures the stability of the DC side voltage, thereby ensuring efficient and stable operation of the entire circuit.

[0014] In some embodiments, the switch arm unit includes: a first switch arm and a second switch arm; the first switch arm and the second switch arm are connected in parallel; the first output terminal of the AC power supply is connected to the first switch arm via the inductor; and the second output terminal of the AC power supply is connected to the second switch arm. As a result, the circuit can efficiently perform power factor correction and effectively manage the charging and discharging process of the first capacitor, ensuring that the secondary pulsating power is fully absorbed, thereby improving the stability and efficiency of the entire circuit. Furthermore, this structure supports more precise current control, helping to reduce circuit size, reduce costs, and improve overall performance.

[0015] In some embodiments, the first switching arm includes: a first switching transistor and a second switching transistor; the gate of the first switching transistor is connected to the control unit, the source of the first switching transistor is connected to the drain of the second switching transistor and the other end of the inductor, and the drain of the first switching transistor is connected to one end of the second switching arm and the other end of the second capacitor; the gate of the second switching transistor is connected to the control unit, and the source of the second switching transistor is connected to the other end of the first capacitor, one end of the second capacitor, and the other end of the second switching arm. This effectively controls the secondary pulsating power absorption process in the first capacitor, improving the efficiency and stability of the entire circuit.

[0016] In some embodiments, the second switch bridge arm includes: a third switch tube and a fourth switch tube; the gate of the third switch tube is connected to the control unit, the source of the third switch tube is respectively connected to the drain of the fourth switch tube and the second output terminal of the AC power supply, and the drain of the third switch tube is respectively connected to the other end of the second capacitor and one end of the first switch bridge arm; the gate of the fourth switch tube is connected to the control unit, the source of the fourth switch tube is respectively connected to the other end of the first capacitor, one end of the second capacitor and the other end of the first switch bridge arm, and the drain of the fourth switch tube is respectively connected to the second output terminal of the AC power supply and the source of the third switch tube. As a result, not only the power factor of the entire control circuit is optimized and unity power factor rectification is achieved, but also the secondary pulsating power can be effectively absorbed, the stability and purity of the DC side voltage are ensured, and the overall efficiency and performance of the circuit are improved. In addition, this design simplifies the circuit structure, reduces the use of unnecessary components, reduces costs and reduces volume.

[0017] In some embodiments, the control unit controls the on / off state of the switch arm unit to control the first current output from the second output terminal of the AC power supply, including: obtaining a first target current at the second output terminal of the AC power supply; determining a first duty cycle signal based on the first current and the first target current; and controlling the on / off state of the second switch arm based on the first duty cycle signal and a first preset carrier signal so that the first current reaches the first target current. This achieves high-precision current waveform tracking, optimizes the power factor, and ensures efficient and stable circuit operation. This not only improves the dynamic response capability of the control circuit, but also effectively reduces harmonic distortion, improving overall performance.

[0018] In some embodiments, the control unit controls the on / off state of the second switch bridge arm based on the first duty cycle signal and the first preset carrier signal, including: when the first duty cycle signal is higher than the first preset carrier signal, controlling the third switch to conduct and the fourth switch to turn off; and when the first duty cycle signal is lower than the first preset carrier signal, controlling the fourth switch to conduct and the third switch to turn off. This allows for efficient and dynamic regulation of the AC power supply output current.

[0019] In some embodiments, the control unit obtains a first target current at the second output terminal of the AC power supply by: obtaining a DC voltage across the second capacitor and an AC voltage of the AC power supply; determining an AC amplitude of the first target current based on the DC voltage and a preset DC reference voltage; and obtaining the first target current by multiplying the AC amplitude by the AC voltage. In this manner, unity power factor correction and DC side voltage stabilization are simultaneously achieved.

[0020] In some embodiments, the control unit controls the on / off state of the switch arm unit to control the second current flowing through the inductor, including: determining the second target current flowing through the inductor based on the first target current; determining a second duty cycle signal based on the second current and the second target current; and controlling the on / off state of the first switch arm based on the second duty cycle signal and a second preset carrier signal so that the second current reaches the second target current. This achieves high-precision current waveform tracking and optimizes the power factor, allowing the AC power supply to efficiently and stably supply power to the load.

[0021] In some embodiments, the control unit controls the on / off state of the first switch bridge arm based on the second duty cycle signal and the second preset carrier signal, including: when the second duty cycle signal is higher than the second preset carrier signal, controlling the first switch transistor to be turned on and the second switch transistor to be turned off; when the second duty cycle signal is lower than the second preset carrier signal, controlling the second switch transistor to be turned on and the first switch transistor to be turned off. This enables efficient and dynamic regulation of the AC power supply output current.

[0022] In some embodiments, the control unit determines a second target current flowing through the inductor based on the first target current, including: obtaining a third target current flowing through the first capacitor; and obtaining the second target current based on the difference between the first target current and the third target current. This achieves efficient rectification, low harmonic distortion, and stable DC bus voltage output.

[0023] In some embodiments, the control unit obtains a third target current flowing through the first capacitor, including: obtaining a DC voltage across the second capacitor; obtaining a voltage error based on the DC voltage and a preset DC reference voltage; and obtaining the third target current based on the voltage error. This achieves the comprehensive control objectives of DC-side voltage stability, second harmonic suppression, and capacitor voltage balancing. The entire control circuit utilizes a cascade control architecture that eliminates steady-state errors through an outer voltage loop and achieves precise current tracking through an inner current loop, thereby optimizing the dynamic response performance of the control circuit, improving circuit stability and efficiency, and ensuring DC bus voltage stability and efficient operation of the entire circuit.

[0024] In some embodiments, the control unit controls the third current flowing through the first capacitor according to the first current and the second current, including: controlling the first current to reach the first target current, controlling the second current to reach the second target current, so that the third current reaches the third target current. Thus, it is ensured that the first capacitor can effectively absorb the secondary pulsating power, thereby maintaining the stability of the DC side voltage and optimizing the overall performance of the system. This not only achieves efficient coordinated control of the currents of each branch, but also significantly improves the power factor of the control circuit, reduces harmonic distortion, enhances dynamic response capability, and stabilizes the DC side voltage.

[0025] To achieve the above objectives, an embodiment of the second aspect of the present invention discloses a control method for a single-phase full-bridge PFC control circuit, which is used in the single-phase full-bridge PFC control circuit described in any embodiment of the first aspect of the present invention. The control method includes: controlling the on-off state of a switch arm unit to control a first current output from a second output terminal of the AC power supply and a second current flowing through an inductor; and controlling a third current flowing through a first capacitor based on the first current and the second current.

[0026] According to the control method of the single-phase full-bridge PFC control circuit of the embodiment of the present invention, the first current output from the second output terminal of the AC power supply and the second current flowing through the inductor are controlled by controlling the on-off state of the switch bridge arm unit, so as to control the third current flowing through the first capacitor according to the first current and the second current. This can achieve an efficient power factor correction function, while allowing the first capacitor to absorb secondary pulsating power, thereby achieving an overall size reduction and cost reduction, reducing dependence on large-capacity capacitors, and significantly reducing the number of required switching tubes, thereby not only reducing the energy loss caused by switching action, but also reducing costs and improving the stability and reliability of the control circuit.

[0027] To achieve the above-mentioned purpose, an embodiment of a third aspect of the present invention discloses a charging and discharging device, comprising: a single-phase full-bridge PFC control circuit as described in any embodiment of the first aspect of the present invention.

[0028] In some embodiments, the charging and discharging device includes an onboard charger. This improves energy efficiency and enhances the flexibility and convenience of vehicle use, making it particularly suitable for various scenarios requiring a mobile power solution. This simplifies the system architecture and reduces costs.

[0029] According to an embodiment of the present invention, a charging and discharging device comprises an inductor connected to a first input terminal of an AC power supply, which can provide AC power to the inductor. A first capacitor is also connected to the first input terminal of the AC power supply, and similarly, the AC power supply can also provide corresponding AC power to the first capacitor. The other end of the first capacitor is connected to the other end of the first capacitor, and the first capacitor is connected in parallel with the load, forming a stable DC voltage supply structure. This allows the second capacitor to absorb high-frequency ripple generated during the switching process, ensuring the stability and smoothness of the DC voltage output. Furthermore, because the first capacitor can absorb secondary pulsating power, the burden of suppressing voltage fluctuations on the second capacitor on the DC side is effectively reduced, and the demand for the second capacitor is correspondingly reduced, so that the sum of the two capacitances is less than a preset capacitance value, thereby achieving an overall reduction in size and cost.

[0030] The switching bridge arm unit is respectively connected to the other end of the inductor, the other end of the first capacitor, and the second capacitor. By controlling the energy transmission and conversion between these components, efficient power factor correction function is achieved, while reducing dependence on large-capacity capacitors and significantly reducing the number of required switching tubes. It not only reduces the energy loss caused by switching action, but also simplifies the circuit structure, reduces costs, and improves the stability and reliability of the control circuit.

[0031] To achieve the above-mentioned purpose, an embodiment of a fourth aspect of the present invention discloses a vehicle, comprising: a charging and discharging device as described in the embodiment of the third aspect of the present invention.

[0032] In a vehicle according to an embodiment of the present invention, one end of an inductor is connected to a first input terminal of an AC power supply, which can provide AC power to the inductor. One end of a first capacitor is also connected to the first input terminal of the AC power supply, which can similarly provide corresponding AC power to the first capacitor. The other end of the first capacitor is connected to the other end of the second capacitor, and the first capacitor is connected in parallel with the load, forming a stable DC voltage supply structure. This allows the second capacitor to absorb high-frequency ripple generated during switching, ensuring the stability and smoothness of the DC voltage output. Furthermore, because the first capacitor can absorb secondary pulsating power, the burden of suppressing voltage fluctuations on the second capacitor on the DC side is effectively reduced, and the demand for the second capacitor is correspondingly reduced, so that the sum of the two capacitances is less than a predetermined capacitance value, thereby achieving an overall reduction in size and cost.

[0033] The switching bridge arm unit is respectively connected to the other end of the inductor, the other end of the first capacitor, and the second capacitor. By controlling the energy transmission and conversion between these components, efficient power factor correction function is achieved, while reducing dependence on large-capacity capacitors and significantly reducing the number of required switching tubes. It not only reduces the energy loss caused by switching action, but also simplifies the circuit structure, reduces costs, and improves the stability and reliability of the control circuit.

[0034] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which: Figure 1 2 is a schematic diagram of a single-phase full-bridge PFC control circuit according to an embodiment of the present invention; Figure 2 1 is a schematic diagram of a split circuit of a single-phase full-bridge PFC control circuit according to an embodiment of the present invention; Figure 3 is a schematic diagram of a split circuit of a single-phase full-bridge PFC control circuit according to another embodiment of the present invention; Figure 4 is a schematic diagram of the relationship between a duty cycle signal, a preset carrier signal and a driving signal according to an embodiment of the present invention; Figure 5 is a schematic diagram of a control strategy of a circuit according to an embodiment of the present invention; Figure 6 is a schematic diagram of an AC equivalent circuit according to an embodiment of the present invention; Figure 7 is a flow chart of a control method of a single-phase full-bridge PFC control circuit according to an embodiment of the present invention; Figure 8 is a structural block diagram of a charging and discharging device according to an embodiment of the present invention; Figure 9 is a structural block diagram of a vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0037] With the increasing popularity of new energy electric vehicles, the importance of mobile car power banks has become increasingly prominent. As a new energy supply method, mobile car power banks can provide temporary power support when the vehicle's battery is low and there are no nearby charging stations, or when charging stations are queued or malfunctioning, effectively alleviating users' range anxiety. Their greatest advantage is that they can be used 24 / 7 as needed, without being restricted by fixed charging station locations. They are suitable for a variety of scenarios, such as parking lots, residential communities, and highway service areas. Furthermore, mobile car power banks can also power household loads, providing great convenience.

[0038] This type of mobile charging not only helps address the challenges of building charging facilities in older residential areas, but also establishes a cascaded reuse channel for decommissioned batteries, optimizing resource reuse. Given the small size and relatively low power of mobile power banks, vehicle-mounted mobile power banks require a low-power onboard charger to complete charging and discharging operations. This allows mobile power banks to maintain portability while ensuring efficient operation in a variety of application scenarios, further enhancing their practicality and flexibility.

[0039] On-board chargers typically consist of a front-stage PFC circuit and a back-stage DC-DC converter. The main function of the front-stage PFC circuit is to suppress higher harmonics in the input current, reducing grid pollution, while also improving the power factor and providing a stable DC voltage for the back-stage circuits. Single-phase full-bridge PFC circuits are widely used in low-power on-board charging applications due to their controllable input power factor, low input current harmonic content, and excellent dynamic performance. Based on these advantages, the present invention selects a single-phase full-bridge PFC circuit as the front-stage circuit topology for on-board chargers.

[0040] However, traditional single-phase full-bridge PFC circuits have shortcomings in suppressing DC-side secondary ripple, which can cause interference to DC-side devices. This problem is particularly prominent in scenarios with high DC-side voltages or where high voltage accuracy is required. To address this, the present invention adds an energy storage capacitor to the AC side of the traditional circuit. This improvement not only effectively reduces DC-side secondary ripple and mitigates its impact on DC-side devices, but also further improves system stability and accuracy.

[0041] Common single-phase full-bridge PFC circuit control strategies fall into two main categories: indirect current control and direct current control. Indirect current control controls the AC side current by controlling the AC side voltage. It lacks an inner current loop, hence the name indirect current control. Indirect current control offers a simple structure, eliminates the need for input current sampling, employs a simple algorithm, and provides good static characteristics. However, its dynamic performance is poor. Furthermore, the lack of AC current sampling prevents input overcurrent protection, making it less commonly used in practical systems.

[0042] Direct current control strategies directly control the AC current to make it follow the command current. These strategies include hysteresis current control, direct power control, predictive current control, and average current control. They offer fast dynamic response and high control precision, making them widely used in practical systems. While the direct current method has been widely used in single-phase full-bridge PFC circuits, it cannot effectively control the current flowing through the AC capacitors in the improved circuits. The control method provided by the present invention not only controls the input current on the AC side to a sinusoidal wave with unity power factor, but also controls the current flowing through the energy storage capacitor, ensuring that the secondary pulsating power is fully absorbed by the capacitor, resulting in a stable DC voltage output.

[0043] Reference below Figures 1-6 A single-phase full-bridge PFC control circuit according to an embodiment of the present invention is described.

[0044] Figure 1 FIG. 1 is a schematic diagram of a single-phase full-bridge PFC control circuit according to an embodiment of the present invention. Figure 1 As shown, the single-phase full-bridge PFC control circuit 1 includes: an AC power source Eac, an inductor L1, a first capacitor Cdec, a second capacitor Cdc and a switch bridge arm unit 11.

[0045] In which, the AC power supply Eac is used to provide AC power; one end of the inductor L1 is connected to the first output end of the AC power supply Eac; one end of the first capacitor Cdec is connected to the first output end of the AC power supply Eac; one end of the second capacitor Cdc is connected to the other end of the first capacitor Cdec, the second capacitor Cdc is connected in parallel with the load Rdc, and the sum of the capacitances of the first capacitor Cdec and the second capacitor Cdc is less than a preset capacitance value; the switch bridge arm unit 11 is respectively connected to the other end of the inductor L1, the other end of the first capacitor Cdec, and the second capacitor Cdc.

[0046] In an embodiment, Figure 1 As shown, the AC power supply Eac provides the necessary AC input, and its first output terminal is connected to one end of the inductor L1 and one end of the first capacitor Cdec, respectively, and can provide AC power to the inductor L1, as shown in FIG. L1 , and at the same time provides AC power to the first capacitor Cdec, such as ic, where the inductor L1 serves as a PFC filter inductor to improve the current waveform and reduce harmonic distortion.

[0047] The first capacitor, Cdec, absorbs secondary pulsating power. Its other end is connected to a parallel structure consisting of a second capacitor, Cdc, and a load, Rdc. The second capacitor, Cdc, not only supports the voltage but also absorbs high-frequency ripple generated during switching, ensuring stable and smooth DC voltage output.

[0048] Furthermore, the combined capacitance of the first and second capacitors Cdec and Cdc is less than the preset capacitance value. Since the first capacitor Cdec can absorb secondary ripple power, it effectively reduces the burden on the DC-side second capacitor Cdc in suppressing voltage fluctuations. Furthermore, the first capacitor Cdec is optimized for secondary ripple, with lower withstand voltage requirements. Therefore, a relatively small capacitor can be used to accomplish this task without sacrificing performance. Simultaneously, the demand for the second capacitor Cdc is reduced, as it no longer needs to solely handle the entire ripple suppression function. Thus, although the first capacitor Cdec is added to the circuit, the combined capacitance requirement is reduced due to the reduced combined capacitance of the first and second capacitors Cdec, making their combined capacitance far less than the preset capacitance required by a single, large-capacity capacitor in traditional solutions. This results in a smaller overall size and lower cost. By rationally allocating the functions of the first and second capacitors Cdec and Cdc, the circuit's efficiency and cost-effectiveness are improved.

[0049] In addition, the switching bridge arm unit 11 is connected to the other end of the inductor L1, the other end of the first capacitor Cdec, and the second capacitor Cdc. By controlling the energy transmission and conversion between these components, an efficient power factor correction function is achieved while reducing dependence on large-capacity capacitors, thereby improving circuit efficiency while reducing costs and helping to reduce circuit size and weight.

[0050] Thus, by storing the secondary ripple power in the newly added first capacitor Cdec, the present invention effectively reduces the secondary ripple on the DC side, achieving higher power density and a smaller size. Compared to traditional active filter circuits, the control circuit of the present invention not only maintains the advantages of high power density, compact size, and low DC-side capacitance, but also significantly reduces the number of required switches. This not only reduces energy loss caused by switching, but also simplifies the circuit structure, reduces costs, and improves the stability and reliability of the control circuit.

[0051] Thus, in an embodiment of the present invention, one end of the inductor is connected to the first input terminal of the AC power source Eac, which can provide AC power to the inductor L1. One end of the first capacitor Cdec is also connected to the first input terminal of the AC power source Eac. Similarly, the AC power source Eac can also provide corresponding AC power to the first capacitor Cdec. The other end of the first capacitor Cdec is connected to the other end of the first capacitor Cdc, and the first capacitor Cdc is connected in parallel with the load Rdc, forming a stable DC voltage supply structure. This allows the second capacitor Cdc to absorb the high-frequency ripple generated during the switching process, ensuring the stability and smoothness of the DC voltage output. In addition, because the first capacitor Cdec can absorb secondary pulsating power, the burden of the second capacitor Cdc on the DC side in suppressing voltage fluctuations is effectively reduced. The demand for the second capacitor Cdc is also reduced accordingly, so that the sum of the two is less than the preset capacitance value, thereby achieving an overall reduction in size and cost.

[0052] The switching bridge arm unit 11 is respectively connected to the other end of the inductor L1, the other end of the first capacitor Cdec, and the second capacitor Cdc. By controlling the energy transmission and conversion between these components, an efficient power factor correction function is achieved, while reducing the dependence on large-capacity capacitors and significantly reducing the number of required switching tubes. It not only reduces the energy loss caused by switching action, but also simplifies the circuit structure, reduces costs, and improves the stability and reliability of the control circuit.

[0053] In one embodiment of the present invention, the single-phase full-bridge PFC control circuit 1 further includes: a control unit (not shown in the figure), which is connected to the switch bridge unit 11 and is used to control the first current iac output from the second output terminal of the AC power supply Eac and the second current i flowing through the inductor L1 by controlling the on-off state of the switch bridge unit 11. L1 , according to the first current iac and the second current i L1 To control the third current ic flowing through the first capacitor Cdec.

[0054] In the embodiment, the control unit is connected to the switch bridge arm unit 11 and is used to control the on / off state of the switch bridge arm unit 11. Through this control method, the first current iac output from the second output terminal of the AC power source Eac can be adjusted, thereby ensuring that the AC input current is a sine wave with a unity power factor, and adjusting the second current i flowing through the inductor L1. L1 , by controlling the first current iac and the second current i L1 To indirectly control the third current ic flowing through the first capacitor Cdec, so that the secondary pulsating power is completely absorbed. Therefore, the control unit further controls the first current iac and the second current i d by controlling the on-off state of the switch bridge unit 11. L1And the third current IC, not only optimizes the input current waveform and reduces harmonic distortion, but also ensures the stability of the DC side voltage, thereby ensuring the efficient and stable operation of the entire circuit.

[0055] In one embodiment of the present invention, Figure 1 As shown, the switch bridge arm unit 11 includes: a first switch bridge arm 111 and a second switch bridge arm 112; the first switch bridge arm 111 and the second switch bridge arm 112 are connected in parallel; the first output end of the AC power supply Eac is connected to the first switch bridge arm 111 through the inductor L1; the second output end of the AC power supply Eac is connected to the second switch bridge arm 112.

[0056] In an embodiment, the switch bridge arm unit 11 is composed of a first switch bridge arm 111 and a second switch bridge arm 112, and the two switch bridge arms are connected in parallel. Specifically, the first output end of the AC power supply Eac is connected to the first switch bridge arm 111 through the inductor L1, wherein the inductor L1 is used as a filter element to smooth the input current. At the same time, the second output end of the AC power supply Eac is connected to the second switch bridge arm 112. The current path flowing out of the AC power supply Eac can be adjusted by controlling the on-off state of the first switch bridge arm 111 and the second switch bridge arm 112, thereby achieving optimized control of the input current waveform and power factor. Through such a design, the circuit can efficiently perform power factor correction and effectively manage the charging and discharging process of the first capacitor Cdec, ensuring that the secondary pulsating power is fully absorbed, thereby improving the stability and efficiency of the entire circuit. In addition, this structure also supports more precise current control, which helps to reduce circuit volume, reduce costs, and improve overall performance.

[0057] In one embodiment of the present invention, Figure 1 As shown, the first switch bridge arm 111 includes: a first switch tube S1 and a second switch tube S2; the gate of the first switch tube S1 is connected to the control unit, the source of the first switch tube S1 is respectively connected to the drain of the second switch tube S2 and the other end of the inductor L1, and the drain of the first switch tube S1 is respectively connected to one end of the second switch bridge arm 112 and the other end of the second capacitor Cdc; the gate of the second switch tube S2 is connected to the control unit, and the source of the second switch tube S2 is respectively connected to the other end of the first capacitor Cdec, one end of the second capacitor Cdc, and the other end of the second switch bridge arm 112.

[0058] In an embodiment, Figure 1As shown, the gate of the first switch S1 is connected to the control unit for receiving a drive signal to control the first switch S1 and adjusting its on / off state based on the received drive signal. The source of the first switch S1 is connected to the drain of the second switch S2 and one end of the inductor L1, forming part of the current path. The drain of the first switch S1 is connected to one end of the second switch bridge arm 112 and the other end of the second capacitor Cdc, ensuring that current can flow according to control requirements. The gate of the second switch S2 is also connected to the control unit for receiving a drive signal to control the second switch S2 and adjusting its on / off state based on the received drive signal to achieve precise control of the switching action of the second switch S2. The source of the second switch S2 is connected to the other end of the first capacitor Cdec, one end of the second capacitor Cdc, and the other end of the second switch bridge arm 112, allowing these two capacitors and the second switch S2 to work together to meet the functional requirements of the circuit. In this way, the control unit can control the second current i flowing through the inductor L1 by controlling the on / off states of the first and second switches S1 and S2. L1 , thereby indirectly controlling the third current ic flowing through the first capacitor Cdec, so as to effectively control the secondary pulsating power absorption process in the first capacitor Cdec and improve the efficiency and stability of the entire circuit.

[0059] In one embodiment of the present invention, Figure 1 As shown, the second switch bridge arm 112 includes: a third switch tube S3 and a fourth switch tube S4; the gate of the third switch tube S3 is connected to the control unit, the source of the third switch tube S3 is respectively connected to the drain of the fourth switch tube S4 and the second output end of the AC power supply Eac, and the drain of the third switch tube S3 is respectively connected to the other end of the second capacitor Cdc and one end of the first switch bridge arm 111; the gate of the fourth switch tube S4 is connected to the control unit, the source of the fourth switch tube S4 is respectively connected to the other end of the first capacitor Cdec, one end of the second capacitor Cdc, and the other end of the first switch bridge arm 111, and the drain of the fourth switch tube S4 is respectively connected to the second output end of the AC power supply Eac and the source of the third switch tube S3.

[0060] In an embodiment, Figure 1As shown, the second switch arm 112 is composed of a third switch transistor S3 and a fourth switch transistor S4. Specifically, the gate of the third switch transistor S3 is connected to the control unit, which is used to receive a drive signal for controlling the third switch transistor S3 and adjust its on / off state based on the received drive signal to achieve precise control of the switching action of the third switch transistor S3. The source of the third switch transistor S3 is connected to the drain of the fourth switch transistor S4 and the second output terminal of the AC power supply Eac, forming a current input path. The drain of the third switch transistor S3 is respectively connected to the other end of the second capacitor Cdc and one end of the first switch arm 111 to achieve effective current distribution and control. That is, the drain of the third switch transistor S3 is respectively connected to the drain of the first switch transistor S1 and one end of the second capacitor Cdc.

[0061] On the other hand, the gate of the fourth switch S4 is also connected to the control unit to ensure switching operation as needed. The source of the fourth switch S4 is connected to the other end of the first capacitor Cdec, one end of the second capacitor Cdc, and the other end of the first switch bridge arm 111, allowing these two capacitors and the fourth switch S4 to operate together. In other words, the source of the fourth switch S4 is connected to the source of the second switch S2, the other end of the first capacitor Cdec, and one end of the second capacitor Cdc, respectively. The drain of the fourth switch S4 is connected to the second output terminal of the AC power supply Eac and the source of the third switch S3, completing the circuit.

[0062] Therefore, the control unit can precisely regulate the on / off states of the third and fourth switching transistors S3 and S4, thereby controlling the first current iac at the second output terminal of the AC power source Eac and further controlling the third current ic flowing through the first capacitor Cdec. This not only optimizes the power factor of the entire control circuit and achieves unity power factor rectification, but also effectively absorbs secondary pulsating power, ensuring the stability and purity of the DC-side voltage, and improving the overall efficiency and performance of the circuit. Furthermore, this design simplifies the circuit structure, reduces the use of unnecessary components, and reduces cost and size.

[0063] In a specific embodiment, Figure 2 The figure shows a schematic diagram of the split circuit of the single-phase full-bridge PFC control circuit in the present invention. The circuit is composed of a first switch tube S1, a second switch tube S2, a third switch tube S3, a fourth switch tube S4 and an inductor L1, forming a typical H-bridge PFC circuit. Its main function is to achieve efficient power conversion between the DC side and the AC side. Figure 2 It can be seen that the current output from the first output terminal of the AC power supply Eac flows through the inductor L1, that is, the second current flowing through the inductor L1 is i L1Inductor L1 not only smoothes the AC current waveform but also effectively filters out high-frequency ripple components in the current. This makes the current input to the AC power source Eac closer to an ideal sine waveform, significantly improving the power factor of the control circuit, reducing harmonic distortion, and ensuring DC voltage stability.

[0064] like Figure 3 As shown, another split circuit schematic of the single-phase full-bridge PFC control circuit of the present invention is shown. This circuit consists of a U-phase bridge arm (i.e., the first switch S1 and the second switch S2), an inductor L1, and a first capacitor Cdec. They are connected in parallel on the DC side to form a buck (step-down) circuit, which is used to effectively absorb the secondary ripple power introduced on the AC side. Specifically, the U-phase bridge arm is responsible for regulating the current path and direction, allowing the inductor L1 to smooth the input current and suppress high-frequency ripple; while the first capacitor Cdec is used to absorb the secondary pulsating power caused by transient processes or load changes, thereby stabilizing the DC side voltage and reducing voltage fluctuations. As a result, this control circuit can not only efficiently complete the energy conversion from AC to DC, but also further improve the stability and efficiency of the system, ensuring the smoothness and reliability of the output DC voltage.

[0065] In one embodiment of the present invention, the control unit controls the on-off state of the switch bridge arm unit 11 to control the first current iac output from the second output terminal of the AC power source Eac, including: obtaining the first target current iac of the second output terminal of the AC power source Eac According to the first current iac and the first target current iac Determine a first duty cycle signal; control the on / off state of the second switch bridge arm 112 according to the first duty cycle signal and the first preset carrier signal so that the first current iac reaches the first target current iac .

[0066] In an embodiment, the control unit obtains a first target current iac at the second output terminal of the AC power source Eac. , and the first current iac of the second output terminal of the AC power source Eac is actually measured, and the first target current iac is obtained according to the first current iac actually measured. The voltage deviation between the two is calculated to calculate the corresponding first duty cycle signal. According to the comparison relationship between the first duty cycle signal and the first preset carrier signal, the corresponding driving signal can be determined. Then, the control unit can control the on-off state of the second switch bridge arm 112 (i.e., the third switch tube S3 and the fourth switch tube S4) based on the driving signal, so that the actual first current iac gradually approaches the first target current iac. , thereby achieving high-precision current waveform tracking, optimizing power factor, and ensuring efficient and stable circuit operation. This not only improves the dynamic response capability of the control circuit, but also effectively reduces harmonic distortion and improves overall performance.

[0067] In one embodiment of the present invention, the control unit controls the on-off state of the second switch bridge arm 112 according to the first duty cycle signal and the first preset carrier signal, including: when the first duty cycle signal is higher than the first preset carrier signal, controlling the third switch tube S3 to be turned on and controlling the fourth switch tube S4 to be turned off; when the first duty cycle signal is lower than the first preset carrier signal, controlling the fourth switch tube S4 to be turned on and controlling the third switch tube S3 to be turned off.

[0068] In an embodiment, the control unit determines the on-off state of the third switch tube S3 and the fourth switch tube S4 in the second switch bridge arm 112 by comparing the first duty cycle signal with the first preset carrier signal. Specifically, when the first duty cycle signal is higher than the first preset carrier signal, the control unit controls the third switch tube S3 to turn on and controls the fourth switch tube S4 to turn off, so that the current will flow through the third switch tube S3 to the corresponding circuit part; on the contrary, when the first duty cycle signal is lower than the first preset carrier signal, the control unit will switch the state, control the fourth switch tube S4 to turn on and control the third switch tube S3 to turn off, so that the current path changes to adapt to the regulation requirements. Through this mechanism, the control unit can accurately adjust the on-off state of the current flowing through the second switch bridge arm 112 to ensure that the actual first current iac is as close as possible to the first target current value iac. , to achieve efficient and dynamic regulation of the output current of the AC power supply Eac.

[0069] Specifically, if Figure 4 As shown, the first duty cycle signal is a sine wave, the first preset carrier signal is a triangular carrier, and the square wave is a driving signal determined based on a comparison result between the first duty cycle signal and the first preset carrier signal.

[0070] In a specific embodiment, when unipolar modulation is adopted, only two switch tubes are turned on in each power frequency cycle, while the other two switch tubes remain in the off state. This method helps to reduce switching losses, but will result in a large total harmonic distortion of the AC side inductor current, so a larger input filter inductor is required to compensate. On the contrary, in the bipolar modulation mode, the four switch tubes are alternately turned on. Although the switching loss is increased, it can produce an undistorted AC side inductor current waveform, making the current waveform closer to a sine wave and reducing the harmonic content, so that a smaller input filter inductor can be selected, and it has better dynamic performance. In view of the requirements of the on-board charger for the front-stage rectifier circuit to have high input power factor, low input current harmonics and high DC bus voltage regulation performance, the embodiment of the present invention selects a bipolar modulation mode. In addition, the single-phase full-bridge power factor correction structure under bipolar modulation has only two switching states, which can be concisely represented by a binary logic switching function, as shown in formula (1): (1) in, is the driving signal.

[0071] like Figure 1 As shown, D1 is the first diode on the first switch tube S1, D2 is the second diode on the second switch tube S2, D3 is the third diode on the third switch tube S3, and D4 is the fourth diode on the fourth switch tube S4.

[0072] like Figure 4 As shown, when the first duty cycle signal is higher than the first preset carrier signal, the driving signal =1, the control unit controls the third switch tube S3 and the third diode D3 to be turned on and the fourth switch tube S4 and the fourth diode D4 to be turned off based on the driving signal; when the first duty cycle signal is lower than the first preset carrier signal, the driving signal is -1, the control unit controls the third switch tube S3 and the third diode D3 to be turned off, and controls the fourth switch tube S4 and the fourth diode D4 to be turned on based on the driving signal.

[0073] In one embodiment of the present invention, the control unit obtains a first target current iac at the second output terminal of the AC power source Eac. , including: obtaining the DC voltage Vdc on both sides of the second capacitor Cdc and the AC voltage Vac of the AC power source Eac; according to the DC voltage Vdc and the preset DC reference voltage Vdc Determine the first target current iac AC amplitude Iac; according to the AC amplitude Iac and the AC voltage product Vac, the first target current iac is obtained .

[0074] In an embodiment, Figure 5 As shown, the control unit obtains the actual measured DC voltage Vdc across the second capacitor Cdc and the AC voltage Vac of the AC power source Eac. Then, the DC voltage Vdc and the preset DC reference voltage Vdc are combined. In the input low-pass filter LPF, the low-pass filter LPF is based on the preset DC reference voltage Vdc The DC voltage Vdc is pre-processed to filter out the secondary ripple component in the DC voltage Vdc to prevent voltage fluctuations from interfering with the control of the AC voltage Vac.

[0075] Then, the PI regulator is used to eliminate the preset DC reference voltage Vdc by utilizing the infinite gain characteristic of the PI regulator for DC signals. The steady-state error between the actual measured DC voltage Vdc and the measured DC voltage Vdc is calculated, and an AC amplitude Iac is given. The AC voltage Vac then passes through the PLL phase-locked loop to provide the voltage frequency and phase of the AC measured voltage Vac. According to the AC amplitude Iac output by the PI combined with the voltage frequency and phase information of Vac, the calculated AC amplitude Iac is multiplied by the real-time measured AC voltage Vac to obtain the first target current iac. .

[0076] Finally, the first target current iac The first current iac is input into the current regulator, and the first duty cycle signal is dynamically adjusted according to the PWM (Pulse Width Modulation) signal output by the current regulator. Based on the comparison result of the first duty cycle signal and the first preset carrier signal, a driving signal is determined, and the on-off state of the third switch tube S3 and the fourth switch tube S4 is driven according to the driving signal, forcing the actual first current iac to accurately follow the first target current iac , thereby achieving unity power factor correction and DC side voltage stabilization at the same time.

[0077] The current regulator may be a linear regulator, such as but not limited to a proportional resonance (PR) regulator, or a nonlinear regulator, such as but not limited to a hysteresis regulator.

[0078] In one embodiment of the present invention, the control unit controls the on / off state of the switch bridge unit 11 to control the second current i flowing through the inductor L1. L1 , including: according to the first target current iac Determine the second target current i flowing through the inductor L1 L1 According to the second current i L1 and the second target current i L1 Determine the second duty cycle signal; control the on-off state of the first switch bridge arm 111 according to the second duty cycle signal and the second preset carrier signal, so that the second current i L1 Reaching the second target current i L1 .

[0079] In the embodiment, according to the determined first target current iac , calculate the second target current i that should flow through the inductor L1 L1 , according to the second current i actually measured L1 , and the second target current i L1 The voltage deviation between them is calculated to obtain the corresponding second duty cycle signal. According to the comparison relationship between the second duty cycle signal and the second preset carrier signal, the corresponding driving signal can be determined. Then, the control unit can control the on-off state of the first switch bridge arm 111 (i.e., the first switch tube S1 and the second switch tube S2) based on the driving signal, so that the actual second current i L1 Gradually approaching the second target current i L1 , thereby achieving high-precision current waveform tracking and optimizing the power factor, so that the AC power supply can supply power to the load efficiently and stably.

[0080] In one embodiment of the present invention, the control unit controls the on-off state of the first switch bridge arm 111 according to the second duty cycle signal and the second preset carrier signal, including: when the second duty cycle signal is higher than the second preset carrier signal, controlling the first switch tube S1 to be turned on and controlling the second switch tube S2 to be turned off; when the second duty cycle signal is lower than the second preset carrier signal, controlling the second switch tube S2 to be turned on and controlling the first switch tube S1 to be turned off.

[0081] In an embodiment, the control unit determines the on-off state of the first switch tube S1 and the second switch tube S2 in the first switch bridge arm 111 by comparing the second duty cycle signal with the second preset carrier signal. Specifically, when the second duty cycle signal is higher than the second preset carrier signal, the control unit controls the first switch tube S1 to be turned on and controls the second switch tube S2 to be turned off, so that the current will flow to the corresponding circuit part through the first switch tube S1; on the contrary, when the second duty cycle signal is lower than the second preset carrier signal, the control unit will switch the state, control the second switch tube S2 to be turned on and control the first switch tube S1 to be turned off, so that the current path changes to adapt to the regulation requirements. Through this mechanism, the control unit can accurately adjust the on-off state of the current flowing through the first switch bridge arm 111 to ensure that the actual second current i L1 As close as possible to the first target current value i L1 , to achieve efficient and dynamic regulation of the output current of the AC power supply Eac.

[0082] Specifically, if Figure 4 As shown, when the second duty cycle signal is higher than the second preset carrier signal, the driving signal =1, the control unit controls the first switch tube S1 and the first diode D1 to turn on and controls the second switch tube S2 and the second diode D2 to turn off based on the driving signal; when the second duty cycle signal is lower than the second preset carrier signal, the driving signal =1, the control unit controls the first switch tube S1 and the first diode D1 to be turned off, and controls the second switch tube S2 and the second diode D2 to be turned on based on the driving signal.

[0083] In one embodiment of the present invention, the control unit generates a first target current iac according to the first target current iac. Determine the second target current i flowing through the inductor L1 L1 , including: obtaining a third target current ic flowing through the first capacitor Cdec ; According to the first target current iac and the third target current ic The difference between the two gets the second target current i L1 .

[0084] In an embodiment, the control unit obtains the third target current ic , the third target current ic This reflects the secondary pulsating power requirement that the first capacitor Cdec needs to absorb. Then, based on the energy balance relationship of the circuit, the first target current iac is calculated. With the third target current ic The difference between the two can be used to obtain the second target current i L1 In this way, the control unit can coordinate the first current iac of the AC input and the second current i flowing through the inductor L1. L1 and the relationship between the third current ic flowing through the first capacitor Cdec, thereby achieving high-efficiency rectification, low harmonic distortion and stable DC bus voltage output.

[0085] In one embodiment of the present invention, the control unit obtains a third target current ic flowing through the first capacitor Cdec. , including: obtaining a DC voltage Vdc across the second capacitor Cdc; and determining a DC voltage Vdc based on the DC voltage Vdc and a preset DC reference voltage Vdc. Get a voltage error; get a third target current ic based on the voltage error .

[0086] In an embodiment, Figure 5 As shown, the actual input DC voltage Vdc and the preset DC reference voltage Vdc , using the infinite gain characteristic of the PR regulator at its resonant frequency point, based on the reference voltage Vd To eliminate the steady-state error in the DC power Vdc, thereby achieving the purpose of suppressing subharmonics and generating the third target current ic of the first capacitor Cdec , and based on the obtained first target current iac , the second target current i flowing through the inductor L1 can be calculated through the corresponding relationship between the currents L1 .

[0087] At the same time, the low-pass filter LPF is used to extract the average voltage Vc of the first capacitor Cdec to ensure that it is half of the DC voltage Vdc. The average voltage Vc of the first capacitor Cdec is compared with half of the DC voltage Vdc to obtain the voltage error between the two. This voltage error is then input into the PI regulator to filter out the secondary pulsating component in the voltage of the first capacitor Cdec, thereby avoiding its interference with the control of the average voltage Vc of the first capacitor Cdec, so that the average voltage Vc of the first capacitor Cdec can be stabilized at half of the preset DC reference voltage, that is, Vc=Vdc / 2. Then based on the second target current i L1 and the second current i L1 , the corresponding PWM modulation signal is generated by the current regulator to accurately control the on and off timing of the first switch tube S1 and the second switch tube S2, so that the actually measured first current i L1 Follow the second target current i L1 , thereby indirectly ensuring that the third current ic of the first capacitor Cdec accurately tracks the third target current ic , ultimately achieving the comprehensive control objectives of DC side voltage stability, second harmonic suppression, and capacitor voltage balancing. The entire control circuit uses a cascade control architecture that eliminates steady-state errors through the voltage outer loop and achieves precise current tracking through the current inner loop, thereby optimizing the dynamic response performance of the control circuit, improving circuit stability and efficiency, and ensuring the stability of the DC bus voltage and the efficient operation of the entire circuit. Among them, in order to suppress harmonics of various frequencies, the latent resonant parts of multiple PR regulators can be connected in parallel, that is, a multi-resonant PR regulator. Through the multi-resonant PR regulator, the third target current ic of the first capacitor Cdec can be calculated. .

[0088] In one embodiment of the present invention, the control unit generates a current according to the first current iac and the second current iL1 To control the third current ic flowing through the first capacitor Cdec, including: controlling the first current iac to reach the first target current iac , control the second current i L1 Reaching the second target current i L1 , so that the third current ic reaches the third target current ic .

[0089] In an embodiment, the control unit obtains the first target current iac based on the circuit requirements. and the second target current i L1 By adjusting the on / off states of the third switch tube S3 and the fourth switch tube S4, the actual first current iac reaches the first target current iac By adjusting the on-off state of the first switch tube S1 and the second switch tube S2, the actual second current i L1 Reaching the second target current i L1 In this process, the first current iac absorbs the current waveform that meets the power factor correction requirements from the AC power supply side, and the second current i L1 It is used to adjust the energy flow in the inductor L1 to meet the dynamic requirements of the control circuit. L1 The precise control indirectly realizes the control of the third current ic flowing through the first capacitor Cdec, so that it reaches the third target current ic This utilizes the circuit's energy balance to ensure that the first capacitor, Cdec, can effectively absorb the secondary pulsating power, thereby maintaining the stability of the DC voltage and optimizing overall system performance. This not only achieves efficient, coordinated control of the currents in each branch, but also significantly improves the control circuit's power factor, reduces harmonic distortion, enhances dynamic response, and stabilizes the DC voltage.

[0090] like Figure 6 Figure 2 shows a schematic diagram of the AC side equivalent circuit of an embodiment of the present invention. Su and Sv represent the switching functions of the U and V phases, respectively. When Su or Sv is 1, the upper transistor of the corresponding bridge arm is on (the lower transistor is off), while when Su or Sv is 0, the lower transistor of the corresponding bridge arm is on (the upper transistor is off).

[0091] Specifically, the U-phase bridge arm consists of the first switching tube S1 and the second switching tube S2. When Su is 1, the upper tube of the U-phase bridge arm is turned on and the lower tube is turned off, that is, the first switching tube S1 is turned on and the second switching tube S2 is turned off. On the contrary, when Su is 0, the upper tube of the U-phase bridge arm is turned off and the lower tube is turned on, that is, the first switching tube S1 is turned off and the second switching tube S2 is turned on; similarly, the V-phase bridge arm consists of the third switching tube S3 and the fourth switching tube S4. When Sv is 1, the upper tube of the V-phase bridge arm is turned on and the lower tube is turned off, that is, the third switching tube S3 is turned on and the fourth switching tube S4 is turned off. On the contrary, when Sv is 0, the upper tube of the V-phase bridge arm is turned off and the lower tube is turned on, that is, the third switching tube S3 is turned off and the fourth switching tube S4 is turned on.

[0092] from Figure 6 As can be seen from the figure, the circuit contains two current loops, namely the inner loop consisting of the inductor L1, the first capacitor Cdec and the U-phase bridge arm, and the outer loop consisting of the inductor L1, the AC power supply Eac and the V-phase bridge arm. The current in the inner loop includes the second current i flowing through the inductor L1. L1 The outer loop current includes the first current iac output from the second output terminal of the AC power source Eac, and the third current ic flowing through the first capacitor Cdec. By regulating the loop containing the first current iac, the power of the control circuit is maintained constant, and by regulating the loop containing the third current ic, secondary pulsation is suppressed.

[0093] Specifically, since there is a monotonic relationship between the second current iL1 on the inductor L1 and the switching state of the U-phase bridge arm, the second current iL1 can be controlled by controlling the U-phase bridge arm alone. L1 Precise regulation of the second current i L1 Similarly, the first current iac output from the second output terminal of the AC power source Eac also has a monotonic relationship with the switching state of the V-phase bridge arm, which means that by controlling the V-phase bridge arm alone, the first current iac can be effectively controlled to reach the first target current iac. .

[0094] In order to control the third current ic of the first capacitor Cdec to be equal to the third target current ic , we need to first calculate the current according to the third current ic and the second current i L1 The second target current i of the inductor L1 is calculated based on the relationship between the first current iac and the second target current i L1 Based on this, since the first current i can be adjusted by controlling the U-phase bridge arm alone L1 , making it equal to the calculated second target current i L1 In this way, the third current ic of the first capacitor Cdec can be indirectly controlled to be closer to the third target current ic. .

[0095] Thus, by independently controlling the U-phase bridge arm and the V-phase bridge arm, the second current i of the inductor L1 can be realized respectively. L1 And the effective management of the first current iac output from the second output end of the AC power supply Eac realizes the control of the third current ic of the first capacitor Cdec, thereby achieving precise control of each key current in the entire control circuit, optimizing system performance and ensuring efficient and stable operation.

[0096] According to an embodiment of the present invention, a single-phase full-bridge PFC control circuit comprises an inductor connected to a first input terminal of an AC power source Eac, which can provide AC power to the inductor L1. One end of a first capacitor Cdec is also connected to the first input terminal of the AC power source Eac. Similarly, the AC power source Eac can also provide corresponding AC power to the first capacitor Cdec. The other end of the first capacitor Cdec is connected to the other end of the first capacitor Cdc. The first capacitor Cdc is connected in parallel with the load Rdc, forming a stable DC voltage supply structure. This allows the second capacitor Cdc to absorb high-frequency ripple generated during switching, ensuring the stability and smoothness of the DC voltage output. Furthermore, because the first capacitor Cdec can absorb secondary pulsating power, the burden of suppressing voltage fluctuations on the DC-side second capacitor Cdc is effectively reduced. The demand for the second capacitor Cdc is also reduced, so that the sum of the two capacitors is less than a preset capacitance value, thereby achieving overall size reduction and cost reduction.

[0097] The switching bridge arm unit 11 is respectively connected to the other end of the inductor L1, the other end of the first capacitor Cdec, and the second capacitor Cdc. By controlling the energy transmission and conversion between these components, an efficient power factor correction function is achieved, while reducing the dependence on large-capacity capacitors and significantly reducing the number of required switching tubes. It not only reduces the energy loss caused by switching action, but also simplifies the circuit structure, reduces costs, and improves the stability and reliability of the control circuit.

[0098] A further embodiment of the present invention also discloses a control method for a single-phase full-bridge PFC control circuit.

[0099] like Figure 7 FIG. 1 is a flow chart of a control method for a single-phase full-bridge PFC control circuit according to an embodiment of the present invention. The method includes at least step S1 and step S2.

[0100] Step S1 : controlling the on / off state of the switch bridge arm unit to control a first current output from the second output terminal of the AC power supply and a second current flowing through the inductor.

[0101] Step S2: controlling a third current flowing through the first capacitor according to the first current and the second current.

[0102] In one embodiment of the present invention, controlling the on-off state of a switch bridge arm unit to control a first current output from a second output terminal of an AC power supply includes: obtaining a first target current of the second output terminal of the AC power supply; determining a first duty cycle signal based on the first current and the first target current; and controlling the on-off state of the second switch bridge arm based on the first duty cycle signal and a first preset carrier signal so that the first current reaches the first target current.

[0103] In one embodiment of the present invention, the on-off state of the second switch bridge arm is controlled according to the first duty cycle signal and the first preset carrier signal, including: when the first duty cycle signal is higher than the first preset carrier signal, the third switch tube is controlled to be turned on and the fourth switch tube is controlled to be turned off; when the first duty cycle signal is lower than the first preset carrier signal, the fourth switch tube is controlled to be turned on and the third switch tube is controlled to be turned off.

[0104] In one embodiment of the present invention, obtaining a first target current at the second output terminal of the AC power supply includes: obtaining a DC voltage across the second capacitor and an AC voltage of the AC power supply; determining an AC amplitude of the first target current based on the DC voltage and a preset DC reference voltage; and obtaining the first target current based on the product of the AC amplitude and the AC voltage.

[0105] In one embodiment of the present invention, controlling the on-off state of the switch bridge arm unit to control the second current flowing through the inductor includes: determining the second target current flowing through the inductor based on the first target current; determining a second duty cycle signal based on the second current and the second target current; and controlling the on-off state of the first switch bridge arm based on the second duty cycle signal and the second preset carrier signal so that the second current reaches the second target current.

[0106] In one embodiment of the present invention, the on-off state of the first switch bridge arm is controlled according to the second duty cycle signal and the second preset carrier signal, including: when the second duty cycle signal is higher than the second preset carrier signal, the first switch tube is controlled to be turned on and the second switch tube is controlled to be turned off; when the second duty cycle signal is lower than the second preset carrier signal, the second switch tube is controlled to be turned on and the first switch tube is controlled to be turned off.

[0107] In one embodiment of the present invention, determining the second target current flowing through the inductor according to the first target current includes: obtaining a third target current flowing through the first capacitor; and obtaining the second target current according to the difference between the first target current and the third target current.

[0108] In one embodiment of the present invention, obtaining a third target current flowing through the first capacitor includes: obtaining a DC voltage across the second capacitor; obtaining a voltage error based on the DC voltage and a preset DC reference voltage; and obtaining the third target current based on the voltage error.

[0109] In one embodiment of the present invention, controlling the third current flowing through the first capacitor according to the first current and the second current includes: controlling the first current to reach a first target current, controlling the second current to reach a second target current, so that the third current reaches a third target current.

[0110] According to the control method of the single-phase full-bridge PFC control circuit of the embodiment of the present invention, the first current output from the second output terminal of the AC power supply and the second current flowing through the inductor are controlled by controlling the on-off state of the switch bridge arm unit, so as to control the third current flowing through the first capacitor according to the first current and the second current. This can achieve an efficient power factor correction function, while allowing the first capacitor to absorb secondary pulsating power, thereby achieving an overall size reduction and cost reduction, reducing dependence on large-capacity capacitors, and significantly reducing the number of required switching tubes, thereby not only reducing the energy loss caused by switching action, but also reducing costs and improving the stability and reliability of the control circuit.

[0111] A further embodiment of the present invention also discloses a charging and discharging device.

[0112] like Figure 8 As shown, the charging and discharging device 2 includes the single-phase full-bridge PFC control circuit 1 described in the above embodiment of the present invention.

[0113] In one embodiment of the present invention, the charging and discharging device 2 includes an on-board charger.

[0114] In the embodiment, the charging and discharging device 2 integrates an on-board charger, which not only provides efficient charging function for electric vehicles, but also has energy feedback capability, supporting the reverse transmission of electrical energy in the vehicle battery to the power grid or other loads to achieve discharge operation. Through this design, the on-board charger becomes a multifunctional charging and discharging hub, which can not only quickly replenish electrical energy when the vehicle is low on power, but also release excess electrical energy when needed for other purposes. This not only improves energy utilization efficiency, but also enhances the flexibility and convenience of vehicle use, and is particularly suitable for various scenarios that require mobile power solutions. This simplifies the system structure and reduces costs.

[0115] According to the charging and discharging device 2 of the embodiment of the present invention, one end of the inductor is connected to the first input end of the AC power source Eac, which can provide AC power to the inductor L1. One end of the first capacitor Cdec is also connected to the first input end of the AC power source Eac. Similarly, the AC power source Eac can also provide corresponding AC power to the first capacitor Cdec. The other end of the first capacitor Cdec is connected to the other end of the first capacitor Cdc, and the first capacitor Cdc is connected in parallel with the load Rdc to form a stable DC voltage supply structure. This enables the second capacitor Cdc to absorb the high-frequency ripple generated during the switching process, ensuring the stability and smoothness of the DC voltage output. In addition, because the first capacitor Cdec can absorb secondary pulsating power, it effectively reduces the burden of the second capacitor Cdc on the DC side in suppressing voltage fluctuations. The demand for the second capacitor Cdc is also reduced accordingly, so that the sum of the two is less than the preset capacitance value, thereby achieving an overall reduction in size and cost.

[0116] The switching bridge arm unit 11 is respectively connected to the other end of the inductor L1, the other end of the first capacitor Cdec, and the second capacitor Cdc. By controlling the energy transmission and conversion between these components, an efficient power factor correction function is achieved, while reducing the dependence on large-capacity capacitors and significantly reducing the number of required switching tubes. It not only reduces the energy loss caused by switching action, but also simplifies the circuit structure, reduces costs, and improves the stability and reliability of the control circuit.

[0117] A further embodiment of the present invention also discloses a vehicle.

[0118] In some embodiments, as Figure 9 As shown, the vehicle 3 includes the charging and discharging device 2 described in the above embodiment of the present invention.

[0119] In vehicle 3 according to an embodiment of the present invention, one end of an inductor is connected to a first input terminal of an AC power source Eac, which can provide AC power to inductor L1. One end of a first capacitor Cdec is also connected to the first input terminal of the AC power source Eac. Similarly, the AC power source Eac can also provide corresponding AC power to the first capacitor Cdec. The other end of the first capacitor Cdec is connected to the other end of the first capacitor Cdc. The first capacitor Cdc is connected in parallel with the load Rdc, forming a stable DC voltage supply structure. This allows the second capacitor Cdc to absorb high-frequency ripple generated during switching, ensuring the stability and smoothness of the DC voltage output. In addition, because the first capacitor Cdec can absorb secondary pulsating power, the burden of suppressing voltage fluctuations on the DC-side second capacitor Cdc is effectively reduced. The demand for the second capacitor Cdc is also reduced accordingly, so that the sum of the two capacitors is less than a preset capacitance value, thereby achieving an overall reduction in size and cost.

[0120] The switching bridge arm unit 11 is respectively connected to the other end of the inductor L1, the other end of the first capacitor Cdec, and the second capacitor Cdc. By controlling the energy transmission and conversion between these components, an efficient power factor correction function is achieved, while reducing the dependence on large-capacity capacitors and significantly reducing the number of required switching tubes. It not only reduces the energy loss caused by switching action, but also simplifies the circuit structure, reduces costs, and improves the stability and reliability of the control circuit.

[0121] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0122] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A single-phase full-bridge PFC control circuit, characterized in that: include: AC power supply, used to provide AC power; an inductor, one end of which is connected to the first output end of the AC power supply; a first capacitor, one end of the first capacitor being connected to the first output end of the AC power supply; a second capacitor, one end of the second capacitor being connected to the other end of the first capacitor, the second capacitor being connected in parallel with the load, and the sum of the capacitances of the first capacitor and the second capacitor being less than a preset capacitance value; A switch bridge arm unit is connected to the other end of the inductor, the other end of the first capacitor, and the second capacitor respectively.

2. The single-phase full-bridge PFC control circuit according to claim 1, characterized in that: Also includes: A control unit is connected to the switch bridge arm unit and is used to control a first current output from the second output end of the AC power supply and a second current flowing through the inductor by controlling the on-off state of the switch bridge arm unit, so as to control a third current flowing through the first capacitor according to the first current and the second current.

3. The single-phase full-bridge PFC control circuit according to claim 2, characterized in that: The switch bridge arm unit includes: a first switch bridge arm and a second switch bridge arm; The first switch bridge arm and the second switch bridge arm are connected in parallel; The first output end of the AC power supply is connected to the first switch bridge arm through the inductor; The second output end of the AC power supply is connected to the second switch bridge arm.

4. The single-phase full-bridge PFC control circuit according to claim 3, characterized in that: The first switch bridge arm includes: a first switch tube and a second switch tube; The gate of the first switching tube is connected to the control unit, the source of the first switching tube is connected to the drain of the second switching tube and the other end of the inductor respectively, and the drain of the first switching tube is connected to one end of the second switching bridge arm and the other end of the second capacitor respectively; The gate of the second switch tube is connected to the control unit, and the source of the second switch tube is respectively connected to the other end of the first capacitor, one end of the second capacitor and the other end of the second switch bridge arm.

5. The single-phase full-bridge PFC control circuit according to claim 4, characterized in that: The second switch bridge arm includes: a third switch tube and a fourth switch tube; The gate of the third switching tube is connected to the control unit, the source of the third switching tube is respectively connected to the drain of the fourth switching tube and the second output end of the AC power supply, and the drain of the third switching tube is respectively connected to the other end of the second capacitor and one end of the first switching bridge arm; The gate of the fourth switching tube is connected to the control unit, the source of the fourth switching tube is respectively connected to the other end of the first capacitor, one end of the second capacitor and the other end of the first switch bridge arm, and the drain of the fourth switching tube is respectively connected to the second output end of the AC power supply and the source of the third switching tube.

6. The single-phase full-bridge PFC control circuit according to claim 5, characterized in that: The control unit controls the on-off state of the switch bridge arm unit to control the first current output from the second output end of the AC power supply, including: Obtaining a first target current at a second output terminal of the AC power supply; determining a first duty cycle signal according to the first current and the first target current; The on-off state of the second switch bridge arm is controlled according to the first duty cycle signal and the first preset carrier signal, so that the first current reaches the first target current.

7. The single-phase full-bridge PFC control circuit according to claim 6, characterized in that: The control unit controls the on-off state of the second switch bridge arm according to the first duty cycle signal and the first preset carrier signal, including: When the first duty cycle signal is higher than the first preset carrier signal, controlling the third switch tube to be turned on and controlling the fourth switch tube to be turned off; When the first duty cycle signal is lower than the first preset carrier signal, the fourth switch tube is controlled to be turned on, and the third switch tube is controlled to be turned off.

8. The single-phase full-bridge PFC control circuit according to claim 6, characterized in that: The control unit acquires a first target current at the second output end of the AC power supply, comprising: Obtaining a DC voltage across the second capacitor and an AC voltage of the AC power supply; determining an AC amplitude of the first target current according to the DC voltage and a preset DC reference voltage; The first target current is obtained according to the product of the AC amplitude and the AC voltage.

9. The single-phase full-bridge PFC control circuit according to claim 6, characterized in that: The control unit controls the on-off state of the switch bridge arm unit to control the second current flowing through the inductor, including: determining a second target current flowing through the inductor according to the first target current; determining a second duty cycle signal according to the second current and the second target current; The on-off state of the first switch bridge arm is controlled according to the second duty cycle signal and the second preset carrier signal, so that the second current reaches the second target current.

10. The single-phase full-bridge PFC control circuit according to claim 9, characterized in that: The control unit controls the on-off state of the first switch bridge arm according to the second duty cycle signal and the second preset carrier signal, including: When the second duty cycle signal is higher than the second preset carrier signal, controlling the first switch tube to be turned on and controlling the second switch tube to be turned off; When the second duty cycle signal is lower than the second preset carrier signal, the second switch tube is controlled to be turned on, and the first switch tube is controlled to be turned off.

11. The single-phase full-bridge PFC control circuit according to claim 9, characterized in that: The control unit determines a second target current flowing through the inductor according to the first target current, including: obtaining a third target current flowing through the first capacitor; The second target current is obtained according to the difference between the first target current and the third target current.

12. The single-phase full-bridge PFC control circuit according to claim 11, characterized in that: The control unit acquires a third target current flowing through the first capacitor, including: Obtaining a DC voltage across the second capacitor; obtaining a voltage error according to the DC voltage and a preset DC reference voltage; The third target current is obtained based on the voltage error.

13. The single-phase full-bridge PFC control circuit according to claim 11, characterized in that: The control unit controls a third current flowing through the first capacitor according to the first current and the second current, including: The first current is controlled to reach the first target current, and the second current is controlled to reach the second target current, so that the third current reaches the third target current.

14. A control method for a single-phase full-bridge PFC control circuit, characterized in that: For the single-phase full-bridge PFC control circuit according to any one of claims 1 to 13, the control method comprises: Controlling the on / off state of the switch bridge arm unit to control a first current output from the second output terminal of the AC power supply and a second current flowing through the inductor; A third current flowing through the first capacitor is controlled according to the first current and the second current.

15. A charging and discharging device, characterized in that: include: The single-phase full-bridge PFC control circuit according to any one of claims 1 to 13.

16. The charge and discharge device according to claim 15, characterized in that: The charging and discharging device includes an on-board charger.

17. A vehicle, characterized in that: include: The charging and discharging device according to claim 15.

Images