Single-stage bidirectional vehicle charger and control method thereof

Abstract

The embodiment of the present application discloses a single-stage bidirectional on-board charger and a control method thereof, belonging to the field of power electronics technology. The single-stage bidirectional on-board charger includes: a primary circuit, a resonant inductor, a transformer and a secondary circuit; the resonant inductor is arranged between the primary circuit and the transformer or between the secondary circuit and the transformer; the primary circuit includes a three-phase bridge arm, the transformer includes a first primary coil, a second primary coil and a secondary coil, the first bridge arm midpoint of the three-phase bridge arm is electrically connected to the first end of the first primary coil, the second end of the first primary coil and the first end of the second primary coil are electrically connected to the first polarity end of the input source, the second end of the second primary coil is electrically connected to the second bridge arm midpoint of the three-phase bridge arm, the third bridge arm midpoint of the three-phase bridge arm is electrically connected to the second polarity end of the input source, and the secondary coil of the transformer is electrically connected to the secondary circuit. The embodiment of the present application simplifies the circuit structure of the on-board charger, reduces the volume, and improves reliability.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of power electronics technology, and in particular to a single-stage bidirectional on-board charger and a control method thereof. Background Art

[0002] With the popularization of new energy vehicles, electricity consumption is also continuing to rise. Traditional on-board chargers generally adopt a two-stage topology combining PFC (Power Factor Correction) and HVDC (high-voltage direct current converter). Its circuit structure is complex and the cost is relatively high. The traditional two-stage solution not only includes PFC inductors and bus electrolytic capacitors, but also has a large number of switching tubes. This also leads to many defects in the traditional solution, such as large size, low efficiency, and high cost. In addition, the life of the electrolytic capacitor will be affected by the usage time, which will affect the size and reliability of the on-board charger. Summary of the invention

[0003] The main purpose of the embodiments of the present application is to provide a single-stage bidirectional on-board charger and a control method thereof, aiming to simplify the circuit structure of the on-board charger, reduce the size of the on-board charger, and improve the reliability of the on-board charger.

[0004] To achieve the above object, an embodiment of the present application provides a single-stage bidirectional on-board charger, the single-stage bidirectional on-board charger comprising: a primary circuit, a resonant inductor, a transformer and a secondary circuit;

[0005] The resonant inductor is arranged between the primary circuit and the transformer or between the secondary circuit and the transformer;

[0006] The primary circuit includes a three-phase bridge arm, and the transformer includes a first primary coil, a second primary coil and a secondary coil. The midpoint of the first bridge arm of the three-phase bridge arm is electrically connected to the first end of the first primary coil, the second end of the first primary coil and the first end of the second primary coil are electrically connected to the first polarity end of the input source, the second end of the second primary coil is electrically connected to the midpoint of the second bridge arm of the three-phase bridge arm, the midpoint of the third bridge arm of the three-phase bridge arm is electrically connected to the second polarity end of the input source, and the secondary coil of the transformer is electrically connected to the secondary circuit.

[0007] In one embodiment, the resonant inductor is a coupled inductor, comprising: a first inductor arranged between a midpoint of a first bridge arm of the three-phase bridge arm and a first end of the first primary coil, and a second inductor arranged between a second end of the second primary coil and a midpoint of a second bridge arm of the three-phase bridge arm.

[0008] In one embodiment, the resonant inductor includes a first leakage inductor and a second leakage inductor of the transformer, wherein two ends of the first leakage inductor are respectively electrically connected to a first bridge arm midpoint of the three-phase bridge arm and a first end of the first primary coil, and two ends of the second leakage inductor are respectively electrically connected to a second end of the second primary coil and a second bridge arm midpoint of the three-phase bridge arm.

[0009] In one embodiment, the resonant inductor is a discrete inductor, and the discrete inductor is arranged between the output end of the transformer and the input end of the secondary circuit.

[0010] In one embodiment, the primary circuit further includes a first capacitor for absorbing high-frequency ripples, wherein a first end of the first capacitor is electrically connected to a first bus terminal of the three-phase bridge arm, and a second end of the first capacitor is electrically connected to a second bus terminal of the three-phase bridge arm;

[0011] The three-phase bridge arm includes: a first primary side tube, a second primary side tube, a third primary side tube, a fourth primary side tube, a fifth primary side tube and a sixth primary side tube; the first primary side tube and the second primary side tube are connected in series to form the first bridge arm of the three-phase bridge arm, the third primary side tube and the fourth primary side tube are connected in series to form the second bridge arm of the three-phase bridge arm, the fifth primary side tube and the sixth primary side tube are connected in series to form the third bridge arm of the three-phase bridge arm, the first end of the first primary side tube, the first end of the third primary side tube and the first end of the fifth primary side tube are connected together to form the first bus end of the three-phase bridge arm, and the second end of the second primary side tube, the second end of the fourth primary side tube and the second end of the sixth primary side tube are connected together to form the second bus end of the three-phase bridge arm.

[0012] In one embodiment, the switch control strategy of the first primary tube and the fourth primary tube is a first wave generation strategy, and the switch control strategy of the second primary tube and the third primary tube is a second wave generation strategy. The first wave generation strategy and the second wave generation strategy are complementary and have a duty cycle of 50%.

[0013] In one embodiment, the secondary circuit includes: a DC blocking capacitor, a secondary power conversion circuit and a filter capacitor electrically connected in sequence; the secondary power conversion circuit adopts a full-bridge circuit, a half-bridge circuit or a full-wave rectifier circuit.

[0014] In one embodiment, the secondary side power conversion circuit adopts a full-bridge circuit, which includes two-phase bridge arms, wherein the midpoint of any one of the two-phase bridge arms is connected to the first end of the secondary coil via the DC blocking capacitor, and the midpoint of the other bridge arm is connected to the second end of the secondary coil, the first common point of the two-phase bridge arms is connected to the first end of the filter capacitor, and the second common point of the two-phase bridge arms is connected to the second end of the filter capacitor.

[0015] In one embodiment, the two-phase bridge arm includes: a first secondary side tube, a second secondary side tube, a third secondary side tube and a fourth secondary side tube; the first secondary side tube and the second secondary side tube are connected in series to form the first bridge arm of the two-phase bridge arm, the third secondary side tube and the fourth secondary side tube are connected in series to form the second bridge arm of the two-phase bridge arm, the second end of the first secondary side tube and the first end of the second secondary side tube are connected together to form the midpoint of the first bridge arm of the two-phase bridge arm, and the second end of the third secondary side tube and the first end of the fourth secondary side tube are connected together to form the midpoint of the second bridge arm of the two-phase bridge arm.

[0016] In one embodiment, the switch control strategy of the first secondary side tube is a third wave generation strategy, the switch control strategy of the second secondary side tube is a fourth wave generation strategy, the switch control strategy of the third secondary side tube is a fifth wave generation strategy, and the switch control strategy of the fourth secondary side tube is a sixth wave generation strategy. The third wave generation strategy and the fourth wave generation strategy are complementary and have a duty cycle of 50%, the fifth wave generation strategy and the sixth wave generation strategy are complementary, the third wave generation strategy differs from the switch control strategy of the first primary side tube in the three-phase bridge arm by a phase angle of α, and the fifth wave generation strategy lags behind the third wave generation strategy by a phase angle of β.

[0017] In one embodiment, when the single-stage bidirectional on-board charger is in charging mode, the third wave generation strategy lags behind the switch control strategy of the first primary side tube in the three-phase bridge arm by a phase angle α; when the single-stage bidirectional on-board charger is in discharging mode, the third wave generation strategy leads the switch control strategy of the first primary side tube in the three-phase bridge arm by a phase angle α.

[0018] In one embodiment, the value range of β is -0.5 to 0.5, and the value range of α is -0.25 to 0.25.

[0019] In addition, to achieve the above-mentioned purpose, the embodiment of the present application further provides a control method of a single-stage bidirectional on-board charger, and the control method of the single-stage bidirectional on-board charger is applied to the single-stage bidirectional on-board charger as described above, and the control method includes:

[0020] Obtaining the working mode of the single-stage bidirectional on-board charger;

[0021] Which switch control strategy to adopt to control the switch tubes in the primary circuit and the secondary circuit is determined according to the working mode.

[0022] In one embodiment, the step of determining which switch control strategy to adopt to control the switch tubes in the primary circuit and the secondary circuit according to the working mode includes at least one of the following:

[0023] When the working mode is the charging mode, the first wave generation strategy is adopted to control the first primary tube and the fourth primary tube in the primary circuit, the second wave generation strategy is adopted to control the second primary tube and the third primary tube in the primary circuit, the third wave generation strategy is adopted to control the first secondary tube in the secondary circuit, the fourth wave generation strategy is adopted to control the second secondary tube in the secondary circuit, the fifth wave generation strategy is adopted to control the third secondary tube in the secondary circuit, and the sixth wave generation strategy is adopted to control the fourth secondary tube in the secondary circuit; wherein the first wave generation strategy and the second wave generation strategy are complementary and have a duty cycle of 50%, the third wave generation strategy is complementary to the fourth wave generation strategy, the fifth wave generation strategy is complementary to the sixth wave generation strategy, the third wave generation strategy lags behind the first wave generation strategy by a phase angle of α, and the fifth wave generation strategy lags behind the third wave generation strategy by a phase angle of β;

[0024] When the working mode is the discharge mode, the first wave generation strategy is adopted to control the first primary tube and the fourth primary tube in the primary circuit, the second wave generation strategy is adopted to control the second primary tube and the third primary tube in the primary circuit, the seventh wave generation strategy is adopted to control the first secondary tube in the secondary circuit, the eighth wave generation strategy is adopted to control the second secondary tube in the secondary circuit, the ninth wave generation strategy is adopted to control the third secondary tube in the secondary circuit, and the tenth wave generation strategy is adopted to control the fourth secondary tube in the secondary circuit; wherein, the first wave generation strategy and the second wave generation strategy are complementary and have a duty cycle of 50%, the seventh wave generation strategy is complementary to the eighth wave generation strategy, the ninth wave generation strategy is complementary to the tenth wave generation strategy, the seventh wave generation strategy leads the first wave generation strategy by a phase angle of α, and the ninth wave generation strategy lags the seventh wave generation strategy by a phase angle of β.

[0025] The embodiment of the present application proposes a single-stage bidirectional on-board charger and a control method thereof, which overcomes the problems of complex circuit structure, large volume and insufficient reliability of on-board chargers in related technologies. The single-stage bidirectional on-board charger includes: a primary circuit, a resonant inductor, a transformer and a secondary circuit; the resonant inductor is arranged between the primary circuit and the transformer or between the secondary circuit and the transformer; the primary circuit includes a three-phase bridge arm, the transformer includes a first primary coil, a second primary coil and a secondary coil, the first bridge arm midpoint of the three-phase bridge arm is electrically connected to the first end of the first primary coil, the second end of the first primary coil and the first end of the second primary coil are electrically connected to the first polarity end of the input source, the second end of the second primary coil is electrically connected to the second bridge arm midpoint of the three-phase bridge arm, the third bridge arm midpoint of the three-phase bridge arm is electrically connected to the second polarity end of the input source, and the secondary coil of the transformer is electrically connected to the secondary circuit.

[0026] The single-stage bidirectional on-board charger provided in the embodiment of the present application eliminates the PFC inductor and electrolytic capacitor in the traditional on-board charger, and reduces the number of switch tubes by integrating the PFC and DCDC functions in the primary circuit, thereby greatly reducing the board area and volume of the on-board charger, greatly reducing the cost, and significantly improving the efficiency; because the electrolytic capacitor is eliminated, the service life and reliability of the whole machine are also improved; in addition, because the single-stage bidirectional on-board charger provided in the embodiment of the present application converts the output ripple current into a ripple voltage, the size of the differential mode filter connected to the output side can also be significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of the structure of a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0029] Figure 2 A schematic diagram of an exemplary structure and installation position of a resonant inductor involved in a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0030] Figure 3 A schematic diagram of another example of the structure and installation position of a resonant inductor involved in a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0031] Figure 4 A schematic diagram of another exemplary structure and installation position of a resonant inductor involved in a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0032] Figure 5 A schematic diagram of another exemplary structure and installation position of a resonant inductor involved in a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0033] Figure 6 A detailed structural diagram of a primary circuit in a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0034] Figure 7 A detailed structural diagram of a secondary circuit in a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0035] Figure 8A schematic diagram of a structure in which a full-bridge circuit is used as a secondary power conversion circuit in a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0036] Fig. 9 Another structural schematic diagram of a single-stage bidirectional on-board charger provided in an embodiment of the present application in which a secondary power conversion circuit adopts a full-bridge circuit;

[0037] Fig.10 A schematic diagram of a timing waveform of a switch control strategy involved in a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0038] Fig.11 A flow chart of a control method for a single-stage bidirectional on-board charger provided in an embodiment of the present application;

[0039] Fig.12 A detailed flowchart of a control method for a single-stage bidirectional on-board charger provided in an embodiment of the present application.

[0040] The realization of the purpose, functional features and advantages of the embodiments of the present application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0041] Description of Figure Numbers:

[0042] 100, primary circuit; 200, resonant inductor; T, transformer; 300, secondary circuit; 101, three-phase bridge arm; a, midpoint of the first bridge arm of the three-phase bridge arm; b, midpoint of the second bridge arm of the three-phase bridge arm; Vin, input side; Lr1, first inductor; Lr2, second inductor; Lk1, first leakage inductor; Lk2, second leakage inductor; P1, first primary tube; P2, second primary tube; P3, third primary tube; P4, The fourth primary tube; P5, the fifth primary tube; P6, the sixth primary tube; C1, the first capacitor; Cbs, the DC blocking capacitor; 310, the secondary power conversion circuit; C2, the filter capacitor; 301, the two-phase bridge arm; S1, the first secondary tube; S2, the second secondary tube; S3, the third secondary tube; S4, the fourth secondary tube; c, the midpoint of the first bridge arm of the two-phase bridge arm; d, the midpoint of the second bridge arm of the two-phase bridge arm; Vout, the output side. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the embodiments of the present application.

[0044] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0045] In addition, in the embodiments of the present application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the embodiments of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the meaning of "and / or" appearing in the full text is to include three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B.

[0046] In the embodiments of the present application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0047] It should also be understood that the references to "one embodiment" or "some embodiments" described in the specification of the embodiments of the present application mean that one or more embodiments of the embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0048] With the popularization of new energy vehicles, electricity consumption is also continuing to rise. Traditional on-board chargers generally adopt a two-stage topology combining PFC (Power Factor Correction) and HVDC (high-voltage direct current converter), which includes PFC rectifier bridge arm, PFC power inductor, bus electrolytic capacitor, HVAC side H-bridge, resonant inductor, transformer, HVDC side H-bridge and other components. The front-stage PFC performs power factor correction, and the rear-stage adjusts the output voltage and current.

[0049] It can be seen that the traditional two-stage solution not only includes PFC inductors and busbar electrolytic capacitors, but also has a large number of switch tubes, which also leads to the large size, low efficiency, high cost, and the electrolytic capacitors are likely to affect the product life and reliability. Among them, the electrolytic capacitor has a large area and its height is often the main reason why the height of the on-board charger cannot be reduced. Because of these defects, the layout of the electrolytic capacitor is often a difficult point. Affected by the layout, the current distribution of the electrolytic capacitor is uneven, which in turn leads to a decrease in the life of the electrolytic capacitor; and the PFC inductor is affected by the DC bias, and the volume and cost it occupies are the most important part of the on-board charger.

[0050] Based on this, the embodiment of the present application provides a single-stage bidirectional on-board charger and a control method thereof. The single-stage bidirectional on-board charger eliminates the PFC inductor and electrolytic capacitor in the traditional on-board charger, and integrates the PFC and HVDC primary sides in the primary circuit, thereby reducing the number of switching tubes, greatly reducing the board area and volume of the on-board charger, greatly reducing the cost, and significantly improving the efficiency; because the electrolytic capacitor is removed, the service life and reliability of the whole machine are also improved; in addition, since the single-stage bidirectional on-board charger provided in the embodiment of the present application converts the output ripple current into a ripple voltage, the size of the differential mode filter connected to the output side can also be significantly reduced.

[0051] The single-stage bidirectional on-board charger and the control method thereof provided in the embodiments of the present application are specifically described through the following embodiments. First, the single-stage bidirectional on-board charger in the embodiments of the present application is described.

[0052] The present application embodiment provides a single-stage bidirectional vehicle charger. Figure 1 , Figure 1 A schematic diagram of the structure of a single-stage bidirectional on-board charger provided in an embodiment of the present application, the single-stage bidirectional on-board charger comprises: a primary circuit 100, a resonant inductor 200, a transformer T and a secondary circuit 300;

[0053] The resonant inductor 200 is arranged between the primary circuit 100 and the transformer T or between the secondary circuit 300 and the transformer T;

[0054] The primary circuit 100 includes a three-phase bridge arm 101, and the transformer T includes a first primary coil, a second primary coil and a secondary coil. The midpoint of the first bridge arm of the three-phase bridge arm 101 is electrically connected to the first end of the first primary coil, the second end of the first primary coil and the first end of the second primary coil are electrically connected to the first polarity end of the input source, the second end of the second primary coil is electrically connected to the midpoint of the second bridge arm of the three-phase bridge arm 101, and the midpoint of the third bridge arm of the three-phase bridge arm 101 is electrically connected to the second polarity end of the input source. The secondary coil of the transformer T is electrically connected to the secondary circuit 300.

[0055] It should be noted that Figure 1 It can be seen that in this embodiment, the setting position of the resonant inductor 200 can be between the primary circuit 100 and the transformer T, or between the secondary circuit 300 and the transformer T; the second end of the first primary coil and the first end of the second primary coil can be the middle tap of the primary coil of the transformer T, or can be other positions where the primary coil is divided according to actual needs, and this embodiment does not limit this; the input source can be a power grid or other types of AC sources, the first polarity end and the second polarity end can represent the live wire L and the neutral wire N respectively, and the polarities of the two polarity ends can be swapped according to actual needs, and this embodiment does not limit this.

[0056] The present embodiment provides a single-stage bidirectional on-board charger, which removes the PFC inductor and electrolytic capacitor in the traditional on-board charger. By integrating the PFC and HVDC primary in the primary circuit 100, the number of switches is reduced, the board area and volume of the on-board charger are greatly reduced, the cost is greatly reduced, and the efficiency is significantly improved. Based on a suitable switch control strategy, the switches in the primary circuit 100 and the secondary circuit 300 provided in the present embodiment are turned on and off, and power factor correction and output power control can still be achieved; because the electrolytic capacitor is removed, the service life and reliability of the whole machine are also improved; in addition, because the single-stage bidirectional on-board charger provided in the embodiment of the present application converts the output current ripple into voltage ripple, the size of the differential mode filter connected to the output side can also be significantly reduced.

[0057] Reference Figure 2 In some feasible embodiments, the resonant inductor 200 is a coupled inductor, including: a first inductor Lr1 arranged between the midpoint of the first bridge arm of the three-phase bridge arm 101 and the first end of the first primary coil, and a second inductor Lr2 arranged between the second end of the second primary coil and the midpoint of the second bridge arm of the three-phase bridge arm 101.

[0058] In this embodiment, an optional implementation of the resonant inductor 200 is provided, that is, the resonant inductor 200 is provided between the primary circuit 100 and the transformer T in the form of a coupled inductor.

[0059] Reference Figure 3In some feasible embodiments, the resonant inductor 200 includes a first leakage inductor Lk1 and a second leakage inductor Lk2 of the transformer T, wherein two ends of the first leakage inductor Lk1 are respectively electrically connected to the midpoint of the first bridge arm of the three-phase bridge arm 101 and the first end of the first primary coil, and two ends of the second leakage inductor Lk2 are respectively electrically connected to the second end of the second primary coil and the midpoint of the second bridge arm of the three-phase bridge arm 101.

[0060] In this embodiment, another optional implementation of the resonant inductor 200 is provided, that is, the leakage inductor of the transformer T is integrated and also arranged between the primary circuit 100 and the transformer T.

[0061] Reference Figure 4 and Figure 5 In some feasible embodiments, the resonant inductor 200 is a discrete inductor Lr, and the discrete inductor Lr is arranged between the output end of the transformer T and the input end of the secondary circuit 300 .

[0062] In this embodiment, another optional implementation of the resonant inductor 200 is provided, that is, the resonant inductor 200 is provided between the secondary circuit 300 and the transformer T in the form of a discrete inductor Lr.

[0063] As an example, the discrete inductor Lr can be electrically connected to the first end of the secondary coil of the transformer T and the first input end of the secondary circuit 300 (eg Figure 4 In addition, the discrete inductor Lr can also be electrically connected to the second end of the secondary coil of the transformer T and the second input end of the secondary circuit 300 (as shown in FIG. Figure 5 As shown), as long as the resonant inductor 200 can be arranged in the resonant cavity of the secondary circuit 300, this embodiment does not impose any limitation on this.

[0064] In addition, the resonant inductor 200 can also be set between the primary circuit 100 and the transformer T in the form of a discrete inductor Lr. The setting position of the discrete inductor Lr can be Figure 3 The location of the first leakage inductance Lk1 can also be Figure 3 The location of the second leakage inductance Lk2.

[0065] Reference Figure 6 In some feasible embodiments, the primary circuit 100 further includes a first capacitor C1 for absorbing high-frequency ripples, a first end of the first capacitor C1 is electrically connected to a first bus terminal of the three-phase bridge arm 101, and a second end of the first capacitor C1 is electrically connected to a second bus terminal of the three-phase bridge arm 101;

[0066] The three-phase bridge arm 101 includes: a first primary tube P1, a second primary tube P2, a third primary tube P3, a fourth primary tube P4, a fifth primary tube P5 and a sixth primary tube P6; the first primary tube P1 and the second primary tube P2 are connected in series to form a first bridge arm of the three-phase bridge arm 101, the third primary tube P3 and the fourth primary tube P4 are connected in series to form a second bridge arm of the three-phase bridge arm 101, the fifth primary tube P5 and the sixth primary tube P6 are connected in series to form a third bridge arm of the three-phase bridge arm 101, the first end of the first primary tube P1, the first end of the third primary tube P3 and the first end of the fifth primary tube P5 are connected together to form a first bus terminal of the three-phase bridge arm 101, and the second end of the second primary tube P2, the second end of the fourth primary tube P4 and the second end of the sixth primary tube P6 are connected together to form a second bus terminal of the three-phase bridge arm 101.

[0067] It can be understood that, in this embodiment, the midpoint of the first bridge arm of the three-phase bridge arm 101 is the connection point of the second end of the first primary tube P1 and the first end of the second primary tube P2, the midpoint of the second bridge arm of the three-phase bridge arm 101 is the connection point of the second end of the third primary tube P3 and the first end of the fourth primary tube P4, and the midpoint of the third bridge arm of the three-phase bridge arm 101 is the connection point of the second end of the fifth primary tube P5 and the first end of the sixth primary tube P6.

[0068] It should be noted that, in this embodiment, the first primary tube P1, the second primary tube P2, the third primary tube P3 and the fourth primary tube P4 are primary fast tubes, and the fast tube refers to a semiconductor power device with fast switching. Specifically, devices such as IGBT (Insulate-Gate Bipolar Transistor) supporting fast switching, MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), SiC (Silicon Carbide) power transistors, etc. can be selected to implement, and the fifth primary tube P5 and the sixth primary tube P6 are industrial frequency tubes. Specifically, devices such as IGBT, thyristor, GTO (gate turn-off thyristor) can be selected to implement, and the specific selection is not limited in this embodiment.

[0069] In this embodiment, in order to achieve power factor correction, in the primary circuit 100, it is generally only necessary to configure appropriate switch control strategies for the first primary tube P1, the second primary tube P2, the third primary tube P3 and the fourth primary tube P4. The fifth primary tube P5 and the sixth primary tube P6 can use conventional control methods, but appropriate switch control strategies can also be configured for the fifth primary tube P5 and / or the sixth primary tube P6 according to actual needs, and this embodiment does not limit this.

[0070] In some feasible embodiments, the switch control strategy of the first primary tube P1 and the fourth primary tube P4 is the first wave generation strategy, and the switch control strategy of the second primary tube P2 and the third primary tube P3 is the second wave generation strategy. The first wave generation strategy and the second wave generation strategy are complementary and have a duty cycle of 50%.

[0071] In this embodiment, the first primary side tube P1 and the fourth primary side tube P4 are opened and closed at the same time, and the second primary side tube P2 and the third primary side tube P3 are opened and closed at the same time; complementarity means that when the first primary side tube P1 and the fourth primary side tube P4 are opened, the second primary side tube P2 and the third primary side tube P3 are closed, and conversely, when the first primary side tube P1 and the fourth primary side tube P4 are closed, the second primary side tube P2 and the third primary side tube P3 are opened.

[0072] As an example, the first primary tube P1, the second primary tube P2, the third primary tube P3 and the fourth primary tube P4 can all be controlled using a 50% duty cycle wave generation strategy (half of the time in a cycle is at a high level and the other half is at a low level), that is, the first wave generation strategy and the second wave generation strategy can be regarded as 50% complementary wave generation, and when the primary fast tube is 50% complementary wave generation, the voltage across the first capacitor C1 is twice the input voltage of the input source.

[0073] Reference Figure 7 In some feasible embodiments, the secondary circuit 300 includes: a DC blocking capacitor Cbs, a secondary power conversion circuit 310 and a filter capacitor C2 electrically connected in sequence; the secondary power conversion circuit 310 adopts a full-bridge circuit, a half-bridge circuit or a full-wave rectifier circuit.

[0074] Reference Figure 8 and Fig. 9 In some feasible embodiments, the secondary power conversion circuit 310 adopts a full-bridge circuit, which includes a two-phase bridge arm 301. The midpoint of any one of the two-phase bridge arms 301 is connected to the first end of the secondary coil via a DC blocking capacitor Cbs, and the midpoint of the other bridge arm is connected to the second end of the secondary coil. The first common point of the two-phase bridge arm 301 is connected to the first end of the filter capacitor C2, and the second common point of the two-phase bridge arm 301 is connected to the second end of the filter capacitor C2.

[0075] In this embodiment, the secondary circuit 300 is described by taking a full-bridge circuit as an example, but it may also be a half-bridge circuit or a full-wave rectifier circuit, which is not limited in this embodiment.

[0076] As an example, the DC blocking capacitor Cbs may be arranged between the first end of the secondary coil and the midpoint of the first bridge arm of the two-phase bridge arm 301 (eg Figure 8 In addition, the DC blocking capacitor Cbs can also be arranged between the second end of the secondary coil and the middle point of the second bridge arm of the two-phase bridge arm 301 (as shown in FIG. Fig. 9As shown), it is sufficient to ensure that the DC blocking capacitor Cbs is disposed in the resonant cavity 302 of the secondary circuit 300, and this embodiment does not impose any limitation on this.

[0077] Reference Figure 8 and Fig. 9 In some feasible embodiments, the two-phase bridge arm 301 includes: a first secondary side tube S1, a second secondary side tube S2, a third secondary side tube S3 and a fourth secondary side tube S4; the first secondary side tube S1 and the second secondary side tube S2 are connected in series to form the first bridge arm of the two-phase bridge arm 301, the third secondary side tube S3 and the fourth secondary side tube S4 are connected in series to form the second bridge arm of the two-phase bridge arm 301, the second end of the first secondary side tube S1 and the first end of the second secondary side tube S2 are connected together to form the midpoint of the first bridge arm of the two-phase bridge arm 301, and the second end of the third secondary side tube S3 and the first end of the fourth secondary side tube S4 are connected together to form the midpoint of the second bridge arm of the two-phase bridge arm 301.

[0078] It can be understood that, in this embodiment, the first common point of the two-phase bridge arm 301 is the connection point of the first end of the first secondary side tube S1 and the first end of the third secondary side tube S3, and the first common point of the two-phase bridge arm 301 is the connection point of the second end of the second secondary side tube S2 and the second end of the fourth secondary side tube S4.

[0079] It should be noted that, in the present embodiment, in order to realize output power control, the first secondary tube S1, the second secondary tube S2, the third secondary tube S3 and the fourth secondary tube S4 need to be configured with appropriate switch control strategies in the secondary circuit 300. The configuration method of the switch control strategy needs to be determined in combination with the switch control strategy of the primary circuit 100, and there needs to be a phase difference between the first bridge arm and the second bridge arm of the two-phase bridge arm 301. Specifically, the first bridge arm of the two-phase bridge arm 301 formed by the first secondary tube S1 and the second secondary tube S2 connected in series can be a leading arm, and the second bridge arm of the two-phase bridge arm 301 formed by the third secondary tube S3 and the fourth secondary tube S4 connected in series is a lagging arm. In addition, the secondary tubes can also be selected from the four secondary tubes according to actual needs to configure appropriate switch control strategies, and the present embodiment does not impose any restrictions on this.

[0080] In some feasible embodiments, the switch control strategy of the first secondary side tube S1 is the third wave generation strategy, the switch control strategy of the second secondary side tube S2 is the fourth wave generation strategy, the switch control strategy of the third secondary side tube S3 is the fifth wave generation strategy, and the switch control strategy of the fourth secondary side tube S4 is the sixth wave generation strategy. The third wave generation strategy and the fourth wave generation strategy are complementary and have a duty cycle of 50%. The fifth wave generation strategy and the sixth wave generation strategy are complementary. The third wave generation strategy differs from the switch control strategy of the first primary side tube P1 in the three-phase bridge arm 101 by a phase angle of α, and the fifth wave generation strategy lags behind the third wave generation strategy by a phase angle of β.

[0081] In this embodiment, complementarity means that when the first secondary side tube S1 is turned on, the second secondary side tube S2 is turned off, when the third secondary side tube S3 is turned on, the fourth secondary side tube S4 is turned off, and vice versa, when the first secondary side tube S1 is turned off, the second secondary side tube S2 is turned on, when the third secondary side tube S3 is turned off, the fourth secondary side tube S4 is turned on.

[0082] As an example, when the first primary tube P1, the second primary tube P2, the third primary tube P3 and the fourth primary tube P4 adopt a 50% complementary wave strategy, the first secondary tube S1, the second secondary tube S2, the third secondary tube S3 and the fourth secondary tube S4 can also be controlled by a wave strategy with a duty cycle of 50% (half of the time in a cycle is high level and the other half of the time is low level), but relative to the primary fast tube, there is a certain phase difference, such as an α phase angle. Therefore, in the first wave strategy, In the case of a clear situation, it is not difficult to derive the third wave-generating strategy and the fourth wave-generating strategy according to the phase difference and the complementary relationship. Moreover, since the first secondary tube S1 and the second secondary tube S2 form a leading arm, and the third secondary tube S3 and the fourth secondary tube S4 form a lagging arm, the phase difference between the two-phase bridge arms 301 can be a β phase angle. Therefore, after the third wave-generating strategy is determined, it is not difficult to derive the fifth wave-generating strategy and the sixth wave-generating strategy according to the phase difference and the complementary relationship. The relative relationship of the wave-generating strategies of the switch tubes mentioned in the above embodiments can be combined with Fig.10 To understand.

[0083] In some feasible embodiments, when the single-stage bidirectional on-board charger is in charging mode, the third wave generation strategy lags behind the switching control strategy of the first primary side tube in the three-phase bridge arm by a phase angle α; when the single-stage bidirectional on-board charger is in discharging mode, the third wave generation strategy leads the switching control strategy of the first primary side tube in the three-phase bridge arm by a phase angle α.

[0084] As an example, in the charging mode, the third wave generation strategy lags behind the first wave generation strategy by a phase angle of α; in the discharging mode, the third wave generation strategy leads the first wave generation strategy by a phase angle of α.

[0085] Combining the above embodiments, it can be concluded that the output power expression of the single-stage bidirectional on-board charger provided in this embodiment is as follows:

[0086]

[0087] Wherein, Vin is the instantaneous value of the grid voltage, Vo is the output voltage, Lr is the resonant inductor, fs is the switching frequency of the switch tube, α and β are the phase angles set in the above embodiments, and Nps is the turns ratio of the transformer. According to the above formula, by designing the resonant inductor Lr and the switching frequency fs, adjusting the phase angles α and β, and combining the AC input voltage Vin, the battery voltage Vo, and the transformer coil turns ratio Nps, the output power of the single-stage bidirectional on-board charger can be calculated. In the formula, α>0 can indicate that the single-stage bidirectional on-board charger is in charging mode, and α<0 can indicate that the single-stage bidirectional on-board charger is in discharging mode.

[0088] In some feasible embodiments, the value range of β is -0.5 to 0.5, and the value range of α is -0.25 to 0.25.

[0089] In addition, the present application also provides a control method for a single-stage bidirectional on-board charger, referring to Fig.11 , Fig.11 Schematic diagram of a control method for a single-stage bidirectional on-board charger provided in an embodiment of the present application. The control method for a single-stage bidirectional on-board charger can be applied to the single-stage bidirectional on-board charger provided in the above embodiment. Fig.11 As shown, the control method of a single-stage bidirectional on-board charger provided in this embodiment includes steps S10 and S20.

[0090] Step S10, obtaining the working mode of the single-stage bidirectional on-board charger;

[0091] Step S20, determining which switch control strategy to adopt to control the switch tubes in the primary circuit and the secondary circuit according to the working mode.

[0092] In this embodiment, the execution subject can be an electronic control device connected to the above-mentioned single-stage bidirectional on-board charger. The electronic control device determines the working mode of the above-mentioned single-stage bidirectional on-board charger through the control method, and then selects a suitable switch control strategy for it so that it can achieve power factor correction and output power control.

[0093] Reference Fig.12 In some feasible embodiments, the above step S20 may specifically include at least one of the following:

[0094] Step S21, when the working mode is the charging mode, the first wave generation strategy is adopted to control the first primary tube and the fourth primary tube in the primary circuit, the second wave generation strategy is adopted to control the second primary tube and the third primary tube in the primary circuit, the third wave generation strategy is adopted to control the first secondary tube in the secondary circuit, the fourth wave generation strategy is adopted to control the second secondary tube in the secondary circuit, the fifth wave generation strategy is adopted to control the third secondary tube in the secondary circuit, and the sixth wave generation strategy is adopted to control the fourth secondary tube in the secondary circuit; wherein the first wave generation strategy and the second wave generation strategy are complementary and the duty cycle is 50%, the third wave generation strategy is complementary to the fourth wave generation strategy, the fifth wave generation strategy is complementary to the sixth wave generation strategy, the third wave generation strategy lags behind the first wave generation strategy by a phase angle of α, and the fifth wave generation strategy lags behind the third wave generation strategy by a phase angle of β;

[0095] Step S22, when the working mode is the discharge mode, the first wave generation strategy is adopted to control the first primary tube and the fourth primary tube in the primary circuit, the second wave generation strategy is adopted to control the second primary tube and the third primary tube in the primary circuit, the seventh wave generation strategy is adopted to control the first secondary tube in the secondary circuit, the eighth wave generation strategy is adopted to control the second secondary tube in the secondary circuit, the ninth wave generation strategy is adopted to control the third secondary tube in the secondary circuit, and the tenth wave generation strategy is adopted to control the fourth secondary tube in the secondary circuit; wherein the first wave generation strategy and the second wave generation strategy are complementary and have a duty cycle of 50%, the seventh wave generation strategy is complementary to the eighth wave generation strategy, the ninth wave generation strategy is complementary to the tenth wave generation strategy, the seventh wave generation strategy is ahead of the first wave generation strategy by a phase angle of α, and the ninth wave generation strategy is behind the seventh wave generation strategy by a phase angle of β.

[0096] It can be understood that, in this embodiment, the first to sixth wave-generation strategies involved in step S21 correspond one-to-one to the corresponding wave-generation strategies in the single-stage bidirectional on-board charger in the charging mode proposed in the above embodiment, and the wave-generation strategies involved in step S22 are to keep the first and second wave-generation strategies unchanged, while the seventh to tenth wave-generation strategies correspond to the third to sixth wave-generation strategies in the single-stage bidirectional on-board charger in the discharging mode proposed in the above embodiment.

[0097] The control method of the single-stage bidirectional on-board charger proposed in this embodiment belongs to the same technical concept as the single-stage bidirectional on-board charger proposed in the above embodiment. The technical details not fully described in this embodiment can be referred to any of the above embodiments, and this embodiment has the same beneficial effects as the above embodiments of the single-stage bidirectional on-board charger.

[0098] It should be noted that the technical solutions of the various embodiments of the embodiments of the present application can be combined with each other, but it must be based on the fact that they can be implemented by technical personnel in this field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the embodiments of the present application.

[0099] The above are only optional embodiments of the embodiments of the present application, and do not limit the patent scope of the embodiments of the present application. Any equivalent structure or equivalent process transformation made using the description and drawings of the embodiments of the present application, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the embodiments of the present application.

Claims

1. A single-stage bidirectional on-board charger, characterized in that: The single-stage bidirectional on-board charger comprises: a primary circuit, a resonant inductor, a transformer and a secondary circuit; The resonant inductor is arranged between the primary circuit and the transformer or between the secondary circuit and the transformer; The primary circuit includes a three-phase bridge arm, and the transformer includes a first primary coil, a second primary coil and a secondary coil. The midpoint of the first bridge arm of the three-phase bridge arm is electrically connected to the first end of the first primary coil, the second end of the first primary coil and the first end of the second primary coil are electrically connected to the first polarity end of the input source, the second end of the second primary coil is electrically connected to the midpoint of the second bridge arm of the three-phase bridge arm, the midpoint of the third bridge arm of the three-phase bridge arm is electrically connected to the second polarity end of the input source, and the secondary coil of the transformer is electrically connected to the secondary circuit.

2. The single-stage bidirectional on-board charger according to claim 1, characterized in that: The resonant inductor is a coupled inductor, including: a first inductor arranged between the midpoint of the first bridge arm of the three-phase bridge arm and the first end of the first primary coil, and a second inductor arranged between the second end of the second primary coil and the midpoint of the second bridge arm of the three-phase bridge arm.

3. The single-stage bidirectional on-board charger according to claim 1, characterized in that: The resonant inductor includes a first leakage inductor and a second leakage inductor of the transformer, wherein two ends of the first leakage inductor are respectively electrically connected to a first bridge arm midpoint of the three-phase bridge arm and a first end of the first primary coil, and two ends of the second leakage inductor are respectively electrically connected to a second end of the second primary coil and a second bridge arm midpoint of the three-phase bridge arm.

4. The single-stage bidirectional on-board charger according to claim 1, characterized in that: The resonant inductor is a discrete inductor, and the discrete inductor is arranged between the output end of the transformer and the input end of the secondary circuit.

5. The single-stage bidirectional on-board charger according to claim 1, characterized in that: The primary circuit further includes a first capacitor for absorbing high-frequency ripples, wherein a first end of the first capacitor is electrically connected to a first bus terminal of the three-phase bridge arm, and a second end of the first capacitor is electrically connected to a second bus terminal of the three-phase bridge arm; The three-phase bridge arm includes: a first primary side tube, a second primary side tube, a third primary side tube, a fourth primary side tube, a fifth primary side tube and a sixth primary side tube; the first primary side tube and the second primary side tube are connected in series to form the first bridge arm of the three-phase bridge arm, the third primary side tube and the fourth primary side tube are connected in series to form the second bridge arm of the three-phase bridge arm, the fifth primary side tube and the sixth primary side tube are connected in series to form the third bridge arm of the three-phase bridge arm, the first end of the first primary side tube, the first end of the third primary side tube and the first end of the fifth primary side tube are connected together to form the first bus end of the three-phase bridge arm, and the second end of the second primary side tube, the second end of the fourth primary side tube and the second end of the sixth primary side tube are connected together to form the second bus end of the three-phase bridge arm.

6. The single-stage bidirectional on-board charger according to claim 4, characterized in that: The switch control strategy of the first primary tube and the fourth primary tube is a first wave generation strategy, and the switch control strategy of the second primary tube and the third primary tube is a second wave generation strategy. The first wave generation strategy and the second wave generation strategy are complementary and have a duty cycle of 50%.

7. The single-stage bidirectional on-board charger according to claim 1, characterized in that: The secondary circuit includes: a DC blocking capacitor, a secondary power conversion circuit and a filter capacitor electrically connected in sequence; the secondary power conversion circuit adopts a full-bridge circuit, a half-bridge circuit or a full-wave rectifier circuit.

8. The single-stage bidirectional on-board charger according to claim 7, characterized in that: The secondary side power conversion circuit adopts a full-bridge circuit, which includes two-phase bridge arms, wherein the midpoint of any one of the two-phase bridge arms is connected to the first end of the secondary coil via the DC blocking capacitor, and the midpoint of the other bridge arm is connected to the second end of the secondary coil, the first common point of the two-phase bridge arms is connected to the first end of the filter capacitor, and the second common point of the two-phase bridge arms is connected to the second end of the filter capacitor.

9. The single-stage bidirectional on-board charger according to claim 8, characterized in that: The two-phase bridge arm includes: a first secondary side tube, a second secondary side tube, a third secondary side tube and a fourth secondary side tube; the first secondary side tube and the second secondary side tube are connected in series to form the first bridge arm of the two-phase bridge arm, the third secondary side tube and the fourth secondary side tube are connected in series to form the second bridge arm of the two-phase bridge arm, the second end of the first secondary side tube and the first end of the second secondary side tube are connected together to form the midpoint of the first bridge arm of the two-phase bridge arm, and the second end of the third secondary side tube and the first end of the fourth secondary side tube are connected together to form the midpoint of the second bridge arm of the two-phase bridge arm.

10. The single-stage bidirectional on-board charger according to claim 9, characterized in that: The switch control strategy of the first secondary side tube is the third wave generation strategy, the switch control strategy of the second secondary side tube is the fourth wave generation strategy, the switch control strategy of the third secondary side tube is the fifth wave generation strategy, and the switch control strategy of the fourth secondary side tube is the sixth wave generation strategy. The third wave generation strategy and the fourth wave generation strategy are complementary and have a duty cycle of 50%. The fifth wave generation strategy and the sixth wave generation strategy are complementary. The third wave generation strategy differs from the switch control strategy of the first primary side tube in the three-phase bridge arm by a phase angle of α, and the fifth wave generation strategy lags behind the third wave generation strategy by a phase angle of β.

11. The single-stage bidirectional on-board charger according to claim 10, characterized in that: When the single-stage bidirectional on-board charger is in charging mode, the third wave generation strategy lags behind the switch control strategy of the first primary side tube in the three-phase bridge arm by a phase angle α; when the single-stage bidirectional on-board charger is in discharging mode, the third wave generation strategy leads the switch control strategy of the first primary side tube in the three-phase bridge arm by a phase angle α.

12. The single-stage bidirectional on-board charger according to claim 11, characterized in that: The value range of β is -0.5 to 0.5, and the value range of α is -0.25 to 0.

25.

13. A control method for a single-stage bidirectional on-board charger, characterized in that: The control method is applied to a single-stage bidirectional on-board charger according to any one of claims 1 to 12, and the control method comprises: Obtaining the working mode of the single-stage bidirectional on-board charger; Which switch control strategy to adopt to control the switch tubes in the primary circuit and the secondary circuit is determined according to the working mode.

14. The control method according to claim 13, characterized in that: The step of determining which switch control strategy to adopt to control the switch tubes in the primary circuit and the secondary circuit according to the working mode includes at least one of the following: When the working mode is the charging mode, the first wave generation strategy is adopted to control the first primary tube and the fourth primary tube in the primary circuit, the second wave generation strategy is adopted to control the second primary tube and the third primary tube in the primary circuit, the third wave generation strategy is adopted to control the first secondary tube in the secondary circuit, the fourth wave generation strategy is adopted to control the second secondary tube in the secondary circuit, the fifth wave generation strategy is adopted to control the third secondary tube in the secondary circuit, and the sixth wave generation strategy is adopted to control the fourth secondary tube in the secondary circuit; wherein the first wave generation strategy and the second wave generation strategy are complementary and have a duty cycle of 50%, the third wave generation strategy is complementary to the fourth wave generation strategy, the fifth wave generation strategy is complementary to the sixth wave generation strategy, the third wave generation strategy lags behind the first wave generation strategy by a phase angle of α, and the fifth wave generation strategy lags behind the third wave generation strategy by a phase angle of β; When the working mode is the discharge mode, the first wave generation strategy is adopted to control the first primary tube and the fourth primary tube in the primary circuit, the second wave generation strategy is adopted to control the second primary tube and the third primary tube in the primary circuit, the seventh wave generation strategy is adopted to control the first secondary tube in the secondary circuit, the eighth wave generation strategy is adopted to control the second secondary tube in the secondary circuit, the ninth wave generation strategy is adopted to control the third secondary tube in the secondary circuit, and the tenth wave generation strategy is adopted to control the fourth secondary tube in the secondary circuit; wherein, the first wave generation strategy and the second wave generation strategy are complementary and have a duty cycle of 50%, the seventh wave generation strategy is complementary to the eighth wave generation strategy, the ninth wave generation strategy is complementary to the tenth wave generation strategy, the seventh wave generation strategy leads the first wave generation strategy by a phase angle of α, and the ninth wave generation strategy lags the seventh wave generation strategy by a phase angle of β.

Images