Circuit capable of simultaneously realizing isolation conversion of three-phase PFC (Power Factor Correction) and DCDC (Direct Current-Direct Current)

Abstract

The utility model relates to the technical field of chargers, in particular to a circuit capable of simultaneously realizing isolation conversion of a three-phase PFC (Power Factor Correction) and a DCDC (Direct Current-Direct Current), which comprises a smooth processing module, a rectification conversion unit and an output load module, the smooth processing module is connected with the rectification conversion unit, and the rectification conversion unit is connected with the output load module. According to the utility model, after the smoothing processing module carries out filtering processing on the current of the input end, the rectification conversion unit carries out isolation conversion processing on the current, the output load module carries out charging output, three-phase rectification and improved T-type DCDC conversion topology are realized by adjusting the duty ratio of a switch tube, and isolation conversion of three-phase PFC and DCDC can be realized at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of chargers, and specifically, to a circuit that can simultaneously achieve isolated conversion of three-phase PFC and DCDC. Background Art

[0002] An electric vehicle charger is a device specifically designed to charge the vehicle battery of an electric vehicle, and it is a power conversion device with specific functions when charging the battery. For example, the existing CN114050723A involves a bidirectional DCDC converter, a control method, and an electric vehicle charging device, including an inverter bridge, an LLC resonant network, an isolation transformer, a synchronous rectification circuit, and a filtering circuit connected in sequence; a second capacitor is connected in series with a normally open switch and then connected in parallel with a first resonant capacitor. After the normally open switch is closed, the parallel capacitance value of the second capacitor and the first resonant capacitor constitutes a second resonant capacitor; in the low-voltage range, the resonant frequencies fr1 and fm1 are obtained from the first resonant capacitor, and the operating frequency varies within the range of fr1 to fm1; in the high-voltage range, the resonant frequencies fr2 and fm2 are obtained from the second resonant capacitor, and the operating frequency varies within the range of fr2 to fm2. This invention solves the problems of wide-range voltage output, high efficiency, high power density, primary-secondary isolation, and low cost, and sets two optimal resonant frequency points within the output voltage range of 200V to 750V, making the resonant current close to a sine wave to greatly improve the converter efficiency. However, the converter in this invention is only a DC / DC converter, and an additional AC / DC converter still needs to be configured when charging an electric vehicle, and this two-stage structure cannot achieve soft switching throughout the process for isolated conversion from alternating current to direct current, and the conversion structure has low efficiency.

[0003] In order to improve the conversion efficiency during electric vehicle charging, a circuit that can simultaneously achieve isolated conversion of three-phase PFC and DCDC is proposed. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a circuit that can simultaneously achieve isolated conversion of three-phase PFC and DCDC to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the utility model provides a circuit that can simultaneously achieve isolated conversion of three-phase PFC and DCDC, including a smoothing processing module, a rectification and conversion unit, and an output load module arranged at the load end. The smoothing processing module is connected to the rectification and conversion unit, and the rectification and conversion unit is connected to the output load module;

[0006] After the smoothing processing module filters the input current, the rectification and conversion unit performs isolated conversion processing on the current and charges and outputs to the output load module.

[0007] As a further improvement of the present technical solution, the smoothing processing module includes inductors LA, LB, and LC connected to the input end;

[0008] The inductor LA is connected to the capacitor C7 and connected to terminal A, the inductor LB is connected to the capacitor C6 and connected to terminal B, and the inductor LC is connected to the capacitor C5 and connected to terminal C;

[0009] The capacitor C5 is connected to the other end of the capacitor C6 and connected to the other end of the capacitor C7.

[0010] As a further improvement of the present technical solution, the rectification and transformation unit includes an anti-backflow module and an adjustment module connected to the anti-backflow module. The anti-backflow module is connected to the smoothing processing module to prevent current backflow, and the adjustment module is used to adjust the phase shift angle of the current.

[0011] As a further improvement of the present technical solution, the anti-backflow module includes diodes D1, D2, D3, D4, D5, and D6,

[0012] The positive electrode of the diode D1 is connected to the negative electrode of the diode D2 and connected to terminal A, and the negative electrode of the diode D1 is connected to the negative electrodes of the diode D3 and the diode D5;

[0013] The positive electrode of the diode D2 is connected to the positive electrodes of the diode D4 and the diode D6;

[0014] The positive electrode of the diode D3 is connected to the negative electrode of the diode D4 and connected to terminal B;

[0015] The positive electrode of the diode D5 is connected to the negative electrode of the diode D6 and connected to terminal C.

[0016] As a further improvement of the present technical solution, the adjustment module includes switching tubes S1, S2, S3, S4, S5, S6, S7, S8, S9, and S10, where:

[0017] One end of the switching tube S1 is connected to the switching tube S3 and connected to the negative electrode of the diode D1, and the other end of the switching tube S1 is connected to the switching tubes S2, S6, S8, and S10;

[0018] The switching tube S2 is connected to the switching tube S4 and connected to the positive electrode of the diode D2;

[0019] The switching tube S3 is connected to the other end of the switching tube S4;

[0020] The switching tube S5 is connected to terminal A and connected to the other end of the switching tube S6;

[0021] The switching tube S7 is connected to terminal B and connected to the other end of the switching tube S8;

[0022] The switching transistor S9 is connected to the C terminal and the other end of the switching transistor S10.

[0023] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0024] In the circuit capable of simultaneously realizing the isolated conversion of three-phase PFC and DCDC, after the smoothing processing module filters the input current, the rectification conversion unit performs isolated conversion processing on the current and charges and outputs to the output load module. By adjusting the duty cycle of the switching transistor, a three-phase rectification plus an improved T-type DCDC conversion topology is achieved, and the isolated conversion of three-phase PFC and DCDC can be simultaneously realized. Description of the Drawings

[0025] Figure 1 is the circuit diagram of the existing SWISS rectifier;

[0026] Figure 2 is the waveform schematic Figure 1 ;

[0027] Figure 3 is the waveform schematic Figure 2 ;

[0028] Figure 4 is the waveform schematic Figure 3 ;

[0029] Figure 5 is the overall structural schematic diagram of the present utility model;

[0030] Figure 6 is the circuit diagram of the smoothing processing module of the present utility model;

[0031] Figure 7 is the circuit diagram of the rectification conversion unit of the present utility model. Detailed Embodiments

[0032] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0033] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0034] Embodiment

[0035] Please refer to Figures 1-7 As shown, this embodiment provides a circuit that can simultaneously achieve isolation transformation of three-phase PFC and DCDC, including a smoothing processing module, a rectification transformation unit, and an output load module arranged at the load end. The smoothing processing module is connected to the rectification transformation unit, and the rectification transformation unit is connected to the output load module;

[0036] After the smoothing processing module filters the input current, the rectification transformation unit performs isolation transformation on the current and charges and outputs to the output load module.

[0037] The smoothing processing module includes inductors LA, LB, and LC connected to the input end;

[0038] Inductor LA is connected to capacitor C7 and connected to terminal A, inductor LB is connected to capacitor C6 and connected to terminal B, and inductor LC is connected to capacitor C5 and connected to terminal C;

[0039] Capacitor C5 is connected to the other end of capacitor C6 and the other end of capacitor C7.

[0040] The rectification transformation unit includes an anti-backflow module and an adjustment module connected to the anti-backflow module. The anti-backflow module is connected to the smoothing processing module to prevent current backflow, and the adjustment module is used to adjust the phase shift angle of the current.

[0041] Among them, the anti-backflow module includes diodes D1, D2, D3, D4, D5, and D6,

[0042] The positive electrode of diode D1 is connected to the negative electrode of diode D2 and connected to terminal A, and the negative electrode of diode D1 is connected to the negative electrodes of diode D3 and diode D5;

[0043] The positive electrode of diode D2 is connected to the positive electrodes of diode D4 and diode D6;

[0044] The positive electrode of diode D3 is connected to the negative electrode of diode D4 and connected to terminal B;

[0045] The positive electrode of diode D5 is connected to the negative electrode of diode D6 and connected to terminal C.

[0046] The adjustment module includes switching transistors S1, S2, S3, S4, S5, S6, S7, S8, S9, and S10, where:

[0047] One end of switching transistor S1 is connected to switching transistor S3 and the negative electrode of diode D1, and the other end of switching transistor S1 is connected to switching transistors S2, S6, S8, and S10;

[0048] Switching transistor S2 is connected to switching transistor S4 and the positive electrode of diode D2;

[0049] Switching transistor S3 is connected to the other end of switching transistor S4;

[0050] Switching transistor S5 is connected to terminal A and the other end of switching transistor S6;

[0051] Switching transistor S7 is connected to terminal B and the other end of switching transistor S8;

[0052] Switching transistor S9 is connected to terminal C and the other end of switching transistor S10.

[0053] As Figures 1-4 shown is a traditional SWISS rectifier. By comparing the magnitudes of Ua, Ub, and Uc, the switching transistor of the middle phase is selected to be turned on. By selecting the intermediate value of the three phases of Ua, Ub, and Uc at a low frequency and selecting the on / off of the middle transistor, the waveforms as shown are achieved. Among them, Upy, Upn, and Uyn are Figure 1 the potential differences between points P, Y, and N in. In this embodiment, high-frequency switching transistors are used to replace the low-frequency selection switches in the SWISS rectifier. S1 - S10 are 10 MOS transistors with high-frequency operation. Among them, switching transistors S1 and S2 are the leading arms, switching transistors S3 and S4 are the lagging arms, and D1 - D6 are high-frequency rectifier diodes.

[0054] The circuit of this embodiment that can simultaneously achieve the isolated transformation of three-phase PFC and DCDC, when specifically used, filters the input current by multiple rectifier diodes provided by the smoothing processing module, and cooperates with the anti-backflow module to prevent current backflow. Then, the adjustment module performs isolated transformation processing on the current, and adjusts the magnitude of the current by adjusting the duty ratios of switching transistor S2 and switching transistor S7, or by adjusting the duty ratios of switching transistor S1 and switching transistor S8. And the charging output is carried out by the output load module. Through three-phase rectification plus an improved T-type DCDC conversion topology, the isolated transformation of three-phase PFC and DCDC can be simultaneously achieved.

[0055] The above has shown and described the basic principles, main features and advantages of the present utility model. Those skilled in the art should understand that the present utility model is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present utility model and are not used to limit the present utility model. Without departing from the spirit and scope of the present utility model, the present utility model will have various changes and improvements, and these changes and improvements all fall within the scope of the present utility model claimed. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents.

Claims

1. A circuit capable of realizing isolation conversion of three-phase PFC and DCDC simultaneously, characterized in that: It includes a smoothing processing module, a rectifying and transforming unit and an output load module arranged at a load end, wherein the smoothing processing module is connected to the rectifying and transforming unit, and the rectifying and transforming unit is connected to the output load module; After the smoothing processing module performs filtering processing on the input end current, the rectifying and transforming unit performs isolation and transformation processing on the current, and performs charging and outputting to the output load module.

2. The circuit capable of realizing isolation conversion of three-phase PFC and DCDC simultaneously according to claim 1, characterized in that: The smoothing processing module includes inductors LA, LB, and LC connected to the input end; The inductor LA is connected to the capacitor C7 and connected to the A terminal, the inductor LB is connected to the capacitor C6 and connected to the B terminal, and the inductor LC is connected to the capacitor C5 and connected to the C terminal; The capacitor C5 is connected to the other end of the capacitor C6 and is also connected to the other end of the capacitor C7.

3. The circuit capable of realizing isolation conversion of three-phase PFC and DCDC simultaneously according to claim 2, characterized in that: The rectifying and transforming unit comprises an anti-backflow module and an adjusting module connected to the anti-backflow module. The anti-backflow module is connected to the smoothing processing module to prevent current backflow, and the adjusting module is used to adjust the phase shift angle of the current.

4. The circuit capable of realizing isolation conversion of three-phase PFC and DCDC simultaneously according to claim 3, characterized in that: The backflow prevention module includes diodes D1, D2, D3, D4, D5, and D6. The anode of the diode D1 is connected to the cathode of the diode D2 and connected to the A terminal, and the cathode of the diode D1 is connected to the cathode of the diode D3 and the cathode of the diode D5; The anode of the diode D2 is connected to the anode of the diode D4 and the anode of the diode D6; The anode of the diode D3 is connected to the cathode of the diode D4 and connected to the B terminal; The anode of the diode D5 is connected to the cathode of the diode D6 and is connected to the C terminal.

5. The circuit capable of realizing isolation conversion of three-phase PFC and DCDC simultaneously according to claim 4, characterized in that: The regulating module includes switch tubes S1, S2, S3, S4, S5, S6, S7, S8, S9, and S10, wherein: One end of the switch tube S1 is connected to the switch tube S3 and connected to the cathode of the diode D1, and the other end of the switch tube S1 is connected to the switch tubes S2, S6, S8, and S10; The switch tube S2 is connected to the switch tube S4 and connected to the positive electrode of the diode D2; The switch tube S3 is connected to the other end of the switch tube S4; The switch tube S5 is connected to the A end and is connected to the other end of the switch tube S6; The switch tube S7 is connected to the B end and connected to the other end of the switch tube S8; The switch tube S9 is connected to the C end and is connected to the other end of the switch tube S10.

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