Single-stage three-port magnetic integration topology, in-vehicle charger, and control method thereof

Abstract

The present application provides a single-stage three-port magnetic integrated topology, an on-board charger and a control method thereof, in which the AC side conversion circuit in the single-stage three-port magnetic integrated topology realizes voltage polarity conversion processing for the AC side of the single-stage three-port magnetic integrated topology, and adopts a matrix conversion structure to realize the power factor correction function instead of the additional PFC rectifier circuit in the prior art, and further, the PFC rectifier circuit and the corresponding PFC inductor and the large-capacity electrolytic capacitor between the positive and negative poles of the intermediate busbar in the subsequent stage in the prior art can be omitted, thereby reducing the number of devices and increasing the power density, and the single-stage conversion structure without the PFC rectifier circuit can reduce one stage of power conversion compared with the prior art, further improving the conversion efficiency and simplifying the control scheme. Furthermore, the high-voltage side can be controlled to realize transport voltage clamping through a low impedance design, thereby realizing port power decoupling and reducing the complexity of control.

Description

Technical Field

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[0001] This application relates to the field of power electronics technology, and particularly to a single-stage three-port magnetic integration topology, an on-vehicle charger, and a control method thereof.

[0002] This application claims the priority of a Chinese patent application filed with the China National Intellectual Property Administration on March 10, 2023, with the application number 202310248243.6 and the application title "Single-stage Three-port Magnetic Integration Topology, On-vehicle Charger, and Control Method Thereof", and incorporates the entire content thereof into this application by reference.

Background Art

[0003] With the rapid development of new energy vehicles, the market share of electric vehicles is increasing. In the current field of passenger cars, on-vehicle chargers belong to an important component of electric vehicles. High integration is its development trend. The conventional magnetic integration technology integrates the outputs of two voltage levels supplied to high-voltage batteries, low-voltage batteries, and low-voltage electrical devices, and significantly improves the utilization rate and power density of devices through a front-stage PFC (Power Factor Correction) rectifier circuit and a rear-stage three-port magnetic integration topology.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, this solution adopts a two-stage cascade structure and has drawbacks such as a large number of devices, low efficiency, and complex control.

[0005] This application provides a single-stage three-port magnetic integration topology, an on-vehicle charger, and a control method thereof that reduce devices, increase conversion efficiency at the same time, and simplify the control solution.

Means for Solving the Problems

[0006] To achieve the above object, this application provides the following technical solutions.

[0007] A first aspect of the present application provides a single-stage three-port magnetic integration topology comprising a transformer, an AC-side conversion circuit, a high-voltage-side conversion circuit, and a low-voltage-side conversion circuit. One side of the AC-side conversion circuit is used as the AC side of the single-stage three-port magnetic integration topology. The other side of the AC-side conversion circuit is connected to the primary winding of the transformer. The AC side of the high-voltage conversion circuit is connected to one of the secondary windings of the transformer. The DC side of the high-voltage side conversion circuit is used as the high-voltage DC side of the single-stage three-port magnetic integration topology. The AC side of the low-voltage conversion circuit is connected to the other secondary windings of the transformer. The DC side of the low-voltage side conversion circuit is used as the low-voltage DC side of the single-stage three-port magnetic integration topology. The AC-side conversion circuit is a matrix conversion structure that realizes voltage polarity conversion processing and power factor correction functions for the AC side of the single-stage three-port magnetic integration topology.

[0008] Preferably, the matrix conversion structure is a three-phase structure, a full-bridge structure, or a half-bridge structure.

[0009] Preferably, the controlled half-bridge arm in the AC-side conversion circuit includes two bidirectional switches connected in series, and the bidirectional switches include two switching tubes connected in reverse series. When the matrix conversion structure is a three-phase structure or a full-bridge structure, a corresponding filter capacitor is further installed between each AC-side phase of the single-stage three-port magnetic integration topology. If the matrix conversion structure is a half-bridge structure, the AC-side conversion circuit further includes two filter capacitors connected in series, the connection point in series is used to connect the primary winding, and both ends of the series connection are connected in parallel with the half-bridge arm to the AC side of the single-stage three-port magnetic integration topology.

[0010] Preferably, the high-voltage side conversion circuit is a full-bridge circuit or a half-bridge circuit.

[0011] Preferably, the low-voltage conversion circuit is a full-bridge circuit, or a cascaded full-wave rectifier circuit and a step-down circuit.

[0012] Preferably, further comprising a first impedance, a second impedance, and a third impedance, The first impedance and the primary winding are connected in series to the corresponding side of the AC-side conversion circuit. The secondary winding corresponding to the second impedance is connected in series with the AC side of the high-voltage side conversion circuit. The secondary winding corresponding to the third impedance is connected in series with the AC side of the low-voltage conversion circuit.

[0013] Preferably, at the switching frequency of the single-stage three-port magnetic integration topology, the impedance value of the second impedance is smaller than the impedance value of the first impedance and the impedance value of the third impedance, and the difference between the impedance value of either the first impedance or the third impedance and the impedance value of the second impedance is greater than a preset threshold.

[0014] Preferably, the impedance value of the first impedance is zero, or the first impedance is at least one of an inductor and a capacitor. The impedance value of the aforementioned second impedance is zero, or the aforementioned second impedance is at least one of an inductor and a capacitor. The impedance value of the aforementioned third impedance is zero, or the aforementioned third impedance is at least one of an inductor and a capacitor.

[0015] Preferably, the impedance value of the second impedance is zero, or the second impedance is a capacitor with a capacitance greater than a preset capacitance.

[0016] Preferably, the inductors in the first impedance and the third impedance are single inductors, or integrated inductors or leakage inductors of the transformer.

[0017] A second aspect of the present application provides an in-vehicle charger comprising a controller and a single-stage three-port magnetic integration topology as described in any one of the first aspects described above. The aforementioned single-stage three-port magnetic integration topology is controlled by the controller.

[0018] A third aspect of the present application provides a control method for an on-board charger that is applied to the controller of the on-board charger described in the second aspect above, the control method being: The steps include obtaining detection parameters for the single-stage three-port magnetic integration topology in the in-vehicle charger and determining the power transmission direction required for the single-stage three-port magnetic integration topology, A step of determining the control parameters of the single-stage three-port magnetic integration topology based on the detection parameters and the power transmission direction, wherein the control parameters include an outward phase shift angle and a switching frequency, The process includes the step of generating and outputting a drive signal for each switching tube in the single-stage three-port magnetic integration topology based on the control parameters.

[0019] Preferably, the outward phase shift angle is such that, in the single-stage three-port magnetic integration topology, A first angular phase difference exists between the drive signals of the AC-side conversion circuit and the high-voltage-side conversion circuit, A second angular phase difference exists between the drive signals of the AC-side conversion circuit and the low-voltage-side conversion circuit, This includes a third angular phase difference existing between the drive signals of the high-voltage side conversion circuit and the low-voltage side conversion circuit.

[0020] Preferably, when power is transmitted from the AC side to the high-voltage DC side and the low-voltage DC side of the single-stage three-port magnetic integration topology, both the first angular phase difference and the second angular phase difference are greater than zero. When power is transmitted from the high-voltage DC side to the low-voltage DC side, the third angular phase difference is greater than zero, and the drive signal of the AC-side matrix conversion circuit is off. When power is transmitted from the high-voltage DC side to the AC side and the low-voltage DC side, the first angular phase difference is less than zero, and the third angular phase difference is greater than zero. When power is transmitted from the low-voltage DC side to the high-voltage DC side, the third angular phase difference is less than zero, and the drive signal of the AC-side matrix conversion circuit is off.

[0021] Preferably, when the low-voltage side conversion circuit in the single-stage three-port magnetic integration topology is a full-bridge circuit, the control parameter further includes the internal phase shift angle of the low-voltage side conversion circuit.

[0022] Preferably, the high-voltage side conversion circuit has no internal phase shift angle.

[0023] Preferably, in the AC-side conversion circuit of the single-stage three-port magnetic integration topology, within each half-bridge arm, For the switching tube whose anode of the freewheeling diode points to the high-voltage end of the AC side of the single-stage three-port magnetic integration topology, the drive signal is always an on signal. For the switching tube whose anode of the freewheeling diode points to the low-voltage end of the AC side of the single-stage three-port magnetic integration topology, the drive signal is a complementary high-frequency on-off signal.

Advantages of the Invention

[0024] The single-stage three-port magnetic integration topology provided by this invention employs a matrix conversion structure in which the AC-side conversion circuit performs voltage polarity conversion processing for the AC side of the single-stage three-port magnetic integration topology. This allows for power factor correction in place of the additional PFC rectifier circuit in the prior art, and further eliminates the need for the PFC rectifier circuit and the large-capacity electrolytic capacitors between the corresponding PFC inductor and the positive and negative terminals of the subsequent intermediate busbar, thereby reducing the number of devices and increasing power density. Moreover, the single-stage conversion structure, which omits the PFC rectifier circuit, reduces the power conversion stage by one compared to the prior art, further improving conversion efficiency and simplifying the control scheme.

[0025] To more clearly illustrate embodiments of the present invention or technical concepts in the prior art, the drawings used in the description of embodiments or the prior art will be briefly described below. Clearly, the drawings in the following description are merely embodiments of the present invention, and those skilled in the art can obtain other drawings from these without any creative effort. [Brief explanation of the drawing]

[0026] [Figure 1] This is a schematic diagram of a single-stage three-port magnetic integration topology provided by the embodiment of the present invention. [Figure 2] This is a schematic diagram of the AC-side conversion circuit in a single-stage three-port magnetic integration topology provided by the embodiment of the present invention. [Figure 3] This is another schematic diagram of the AC-side conversion circuit in the single-stage three-port magnetic integration topology provided by the embodiment of the present application. [Figure 4] This is another schematic diagram of the AC-side conversion circuit in the single-stage three-port magnetic integration topology provided by the embodiment of the present application. [Figure 5] This is a schematic diagram of the high-voltage side conversion circuit or the low-voltage side conversion circuit in a single-stage three-port magnetic integration topology provided by the embodiment of the present application. [Figure 6] This is another schematic diagram of the high-voltage side conversion circuit in the single-stage three-port magnetic integration topology provided by the embodiment of the present application. [Figure 7] This is another schematic diagram of the low-voltage side conversion circuit in a single-stage three-port magnetic integration topology provided by the embodiment of the present application. [Figure 8] This is a flowchart of the control method for an in-vehicle charger provided by the embodiment of the present invention. [Figure 9] This is a circuit diagram of a single-stage three-port magnetic integration topology provided by the embodiment of the present application. [Figure 10] This is a drive signal waveform diagram for a single-stage three-port magnetic integration topology provided by an embodiment of the present invention when the power grid voltage is positive. [Figure 11] This is another circuit diagram of the single-stage three-port magnetic integration topology provided by the embodiment of the present application. [Modes for carrying out the invention]

[0027] The technical concepts in the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments. Clearly, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort based on the embodiments of the present invention are within the scope of the protection of the present invention.

[0028] In this application, the terms “includes,” “inclusive,” or any other variation thereof are intended to encompass non-exclusive inclusions such that a process, method, product, or device containing a set of elements includes not only those elements but also other elements not expressly listed, or elements specific to such process, method, product, or device. Unless otherwise limited, an element defined by the phrase “includes one” does not preclude the presence of another identical element in a process, method, product, or device containing the element.

[0029] This invention provides a single-stage, three-port magnetic integration topology that reduces the number of devices, improves conversion efficiency, and simplifies the control scheme.

[0030] As shown in Figure 1, this single-stage three-port magnetic integration topology includes a transformer T, an AC-side conversion circuit 10, a high-voltage-side conversion circuit 20, and a low-voltage-side conversion circuit 30. One side of the AC-side conversion circuit 10 is used as the AC side of the single-stage three-port magnetic integration topology and is used to connect power grids such as single-phase or three-phase power grids, while the other side of the AC-side conversion circuit 10 is connected directly to the primary winding of the transformer T or via a first impedance Z1.

[0031] The AC side of the high-voltage side conversion circuit 20 is connected directly to one secondary winding of the transformer T or via a second impedance Z2, and the DC side of the high-voltage side conversion circuit 20 is used as the high-voltage DC side HV of a single-stage three-port magnetic integration topology and can be connected to the high-voltage battery of an electric vehicle.

[0032] The AC side of the low-voltage side conversion circuit 30 is connected directly to the other secondary windings of the transformer T or via a third impedance Z3, and the DC side of the low-voltage side conversion circuit 30 is used as the low-voltage DC side LV of a single-stage three-port magnetic integration topology and can be connected to the low-voltage battery and low-voltage electrical equipment of an electric vehicle.

[0033] In other words, this single-stage three-port magnetic integration topology mainly includes a power grid-side matrix conversion circuit (i.e., AC-side conversion circuit 10), a first impedance Z1, a high-voltage-side conversion circuit 20, a second impedance Z2, a low-voltage-side conversion circuit 30, a third impedance Z3, and a three-port high-frequency transformer T, through which the AC side, high-voltage DC side HV, and low-voltage DC side LV are connected.

[0034] Furthermore, this AC-side conversion circuit 10 is a matrix conversion structure that realizes voltage polarity conversion processing and power factor correction functions for the AC side of a single-stage three-port magnetic integrated topology.

[0035] In actual applications, the matrix conversion structure that realizes this AC side conversion circuit 10 may specifically be a three-phase structure (shown in Figure 2), a full-bridge structure (shown in Figure 3), or a half-bridge structure (shown in Figure 4). In any case, the matrix conversion structure has a controlled half-bridge arm as its basic unit, and this half-bridge arm consists of four switching tubes connected back-to-back in pairs to form two bidirectional switches, which are then connected in series. That is, each half-bridge arm contains two bidirectional switches, and each bidirectional switch consists of two corresponding switching tubes connected in opposite directions (i.e., back-to-back) in series. Taking the full-bridge structure shown in Figure 3 as an example, the power grid is connected to both ends of the half-bridge arm, and the midpoint of the half-bridge arm is used to connect the impedance (i.e., Z1 in Figure 1) and the transformer T network. Regarding control, in a bidirectional switch, the switching tube whose flywheel diode anode points to the high-voltage terminal of the voltage across the half-bridge arm is driven to be always on, while the switching tube whose flywheel diode anode points to the low-voltage terminal of the voltage across the half-bridge arm is switched on and off in a high-frequency manner, and further performs complementary operation with a duty cycle of 50%. Furthermore, if this matrix conversion structure is a three-phase or full-bridge structure, corresponding filter capacitors are further installed between each AC side phase of this single-stage three-port magnetic integration topology, and if this matrix conversion structure is a half-bridge structure, the AC side conversion circuit 10 further includes two filter capacitors connected in series, the connection point of the two filter capacitors connected in series is used to connect this primary winding, and the ends of the two filter capacitors connected in series are connected in parallel with this half-bridge arm to the AC side of this single-stage three-port magnetic integration topology.

[0036] This high-voltage side conversion circuit 20 may be a full-bridge circuit (shown in Figure 5) or a half-bridge circuit (shown in Figure 6). In this high-voltage side conversion circuit 20, the switching tubes of the half-bridge arm are switched on complementaryally, the duty cycle is 50%, the frequency is the same as that of the high-frequency switching tube in the AC side conversion circuit 10, and the midpoint of the bridge arm generates a positive and negative symmetrical square wave voltage.

[0037] The low-voltage side conversion circuit 30 may be a full-bridge circuit as shown in Figure 5. When the low-voltage side conversion circuit 30 is a full-bridge circuit, the switching tubes of its half-bridge arm are switched on complementaryly, the duty cycle is 50%, the frequency is the same as that of the high-frequency switching tube of the AC side conversion circuit 10, and the midpoint of the bridge arm generates a three-level voltage with a positive and negative symmetrical square wave voltage or zero voltage according to the voltage relationship between the high-voltage DC side HV and the low-voltage DC side LV.

[0038] Alternatively, as shown in Figure 7, the low-voltage side conversion circuit 30 includes a cascaded full-wave rectifier circuit 201 and a step-down circuit (i.e., a Buck circuit) 202, and in this case, the secondary winding to which the low-voltage side conversion circuit 30 is connected is a center-tapped winding. When the low-voltage side conversion circuit 30 is the full-wave rectifier circuit 201 and step-down circuit 202 shown in Figure 7, the on and off times of the full-wave rectifier switching tube are in phase with the switching tube in the high-voltage side conversion circuit 20, and control of the output voltage of the low-voltage DC side LV is achieved by changing the duty cycle of the switching tube in the step-down circuit 202.

[0039] Power transmission between the three ports of this single-stage three-port magnetic integrated topology is achieved by controlling the phase angle changes of the switching tubes in the AC-side conversion circuit 10, the high-voltage-side conversion circuit 20, and the low-voltage-side conversion circuit 30.

[0040] The single-stage three-port magnetic integration topology provided by this embodiment has an AC-side conversion circuit 10 that performs voltage polarity conversion processing for the AC side of the single-stage three-port magnetic integration topology. By adopting a matrix conversion structure, it is possible to realize a power factor correction function instead of the additional PFC rectifier circuit in the conventional technology. Furthermore, by omitting the PFC rectifier circuit and the large-capacity electrolytic capacitor between the corresponding PFC inductance and the positive and negative terminals of the subsequent intermediate busbar in the conventional technology, the number of devices can be reduced and the power density can be increased. Moreover, the single-stage conversion structure without a PFC rectifier circuit can reduce the power conversion stage by one compared to the conventional technology, further improve conversion efficiency, and simplify the control scheme.

[0041] In actual applications, corresponding filter circuits may be further installed on the AC side, high-voltage DC side, and low-voltage DC side LV of this single-stage three-port magnetic integration topology, and this can be determined according to the specific application environment; it is not limited here.

[0042] Furthermore, each switching tube in the AC-side conversion circuit 10 and the high-voltage-side conversion circuit 20 may be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), such as a SiC (Silicon Carbide) MOSFET, an IGBT (Insulated Gate Bipolar Transistor) with an antiparallel diode, or a GaN (Gallium Nitride), and is not limited thereto. Also, the packaging of each device is not limited; the bidirectional switch in the AC-side conversion circuit 10 may be an integrated module type package or a single-tube connection configuration. Each switching tube in the low-voltage-side conversion circuit 30 may be a MOSFET, but is not limited thereto, and can be determined according to the specific application environment.

[0043] Based on the previous embodiment, the single-stage three-port magnetic integration topology provided by this embodiment can be configured in multiple realizations for each impedance, for example, the impedance value of the first impedance Z1 may be zero, or the first impedance Z1 may be at least one of an inductor and a capacitor; the impedance value of the second impedance Z2 may be zero, or the second impedance Z2 may be at least one of an inductor and a capacitor; and the impedance value of the third impedance Z3 may be zero, or the third impedance Z3 may be at least one of an inductor and a capacitor. In other words, impedances Z1, Z2 and Z3 are a combination of an inductor and a capacitor, or one or zero of an inductor and a capacitor (i.e., directly short-circuited, with an impedance value of zero).

[0044] Preferably, at the switching frequency of this single-stage three-port magnetic integration topology, the impedance value of the second impedance Z2 is set to be smaller than the impedance value of the first impedance Z1 and the impedance value of the third impedance Z3, and the difference between the impedance value of either the first impedance Z1 or the third impedance Z3 and the impedance value of the second impedance Z2 is set to be greater than a preset threshold, that is, the impedance value of the second impedance Z2 can be set to be much smaller than the impedance of the first impedance Z1 and the third impedance Z3.

[0045] For example, this second impedance Z2 can be implemented by directly short-circuiting, in which case its impedance value is zero. Alternatively, this second impedance Z2 can be implemented by selecting a capacitor with a capacitance larger than a preset capacitance, i.e., a large-capacity block capacitor, which acts as DC isolation, and its voltage across it is small and does not change much, so it can be considered a short circuit during analysis. If inductors are present in the first impedance Z1 and the third impedance Z3, these inductors can be implemented by selecting a single inductor, an integrated inductor of transformer T, or a leakage inductor.

[0046] When the second impedance Z2 is small, the port voltage of the corresponding secondary winding of the transformer T can be approximated by the AC voltage of the high-voltage side conversion circuit 20, i.e., the midpoint voltage of its bridge arm. Therefore, if the midpoint voltage of the bridge arm of the high-voltage side conversion circuit 20 is a positive and negative symmetrical square wave voltage, the port voltage waveforms of the other windings of the transformer T are also positive and negative square wave voltages, and the ratio between its amplitude and the port voltage amplitude of the secondary winding to which the high-voltage side conversion circuit 20 is connected is the turns ratio of the corresponding windings.

[0047] The single-stage three-port magnetic integration topology provided by this embodiment not only enables three-port power transmission through a single-stage structure, but also achieves clamping of the transformer T-winding port voltage through a high-voltage side low-impedance design, thereby realizing power decoupling between different ports, which is advantageous for simplifying control.

[0048] Other embodiments of the present invention also provide an in-vehicle charger comprising a controller and the single-stage three-port magnetic integration topology described in any of the above embodiments, the single-stage three-port magnetic integration topology being controlled by the controller.

[0049] The structure and principle of this single-stage three-port magnetic integration topology can be found in the above-described embodiment and will not be described in detail here. The specific structure and functions of this controller can be found in the prior art and will not be described again here.

[0050] The in-vehicle charger provided by this embodiment employs this single-stage three-port magnetic integration topology and realizes the AC side conversion circuit 10 with a matrix conversion structure, thereby enabling AC voltage polarity conversion processing and power factor correction functions. Furthermore, its high-voltage side has a low impedance design, which allows the high-voltage side conversion circuit 20 to control the transformer T port voltage clamp, thereby achieving port power decoupling and reducing control complexity.

[0051] Other embodiments of the present invention also provide a control method for an on-board charger that can be applied to the controller of the on-board charger described in the above embodiments. As shown in Figure 8, this control method includes the following steps.

[0052] S101. The detection parameters for the single-stage three-port magnetic integration topology in the in-vehicle charger are obtained, and the power transmission direction required for the single-stage three-port magnetic integration topology is determined.

[0053] Referring to Figure 1, this single-stage three-port magnetic integration topology can realize charging power transmission from the AC side to the high-voltage DC side and / or the low-voltage DC side, discharge power transmission from the high-voltage DC side to the AC side and / or the low-voltage DC side, and power transmission from the low-voltage DC side to the high-voltage DC side. The specific topology can be determined according to the application environment, and all of these fall within the scope of protection of this application.

[0054] Specifically, this in-vehicle charger can detect electrical parameters of the corresponding port, such as voltage detection, after receiving a charge / discharge command. Simultaneously, it can determine the required power transmission direction based on this charge / discharge command.

[0055] S102, based on the detection parameters and power transmission direction, control parameters for the single-stage three-port magnetic integration topology are determined.

[0056] These control parameters may include the outward phase shift angle and the switching frequency.

[0057] When this single-stage three-port magnetic integration topology includes the AC-side conversion circuit 10, the high-voltage-side conversion circuit 20, and the low-voltage-side conversion circuit 30 shown in Figure 1, the outward phase shift angle specifically includes a first angular phase difference between the drive signals of the AC-side conversion circuit 10 and the high-voltage-side conversion circuit 20, a second angular phase difference between the drive signals of the AC-side conversion circuit 10 and the low-voltage-side conversion circuit 30, and a third angular phase difference between the drive signals of the high-voltage-side conversion circuit 20 and the low-voltage-side conversion circuit 30.

[0058] Specifically, when power is transmitted from the AC side (AC) to the high-voltage DC side (HV) and low-voltage DC side (LV) of a single-stage three-port magnetic integration topology, both the first and second angular phase differences are greater than zero. When power is transmitted from the high-voltage DC side (HV) to the low-voltage DC side (LV), the third angular phase difference is greater than zero, and the drive signal for the AC side matrix conversion circuit is off. When power is transmitted from the high-voltage DC side (HV) to the AC side (AC) and low-voltage DC side (LV), the first angular phase difference is less than zero, and the third angular phase difference is greater than zero. When power is transmitted from the low-voltage DC side (LV) to the high-voltage DC side (HV), the third angular phase difference is less than zero, and the drive signal for the AC side matrix conversion circuit is off.

[0059] Furthermore, the switching frequencies of the AC-side conversion circuit 10, the high-voltage-side conversion circuit 20, and the low-voltage-side conversion circuit 30 are the same, and the duty cycles of all three may be 50%, but are not limited to this. In addition, if the low-voltage-side conversion circuit 30 includes the full-wave rectifier circuit 201 and the step-down circuit 202 shown in Figure 7, the duty cycle of the switching tube in the step-down circuit 202 becomes adjustable, and the output voltage of the low-voltage DC-side LV can be controlled.

[0060] Preferably, if the low-voltage side conversion circuit in a single-stage three-port magnetic integration topology is a full-bridge circuit, the control parameters further include the inward phase shift angle of the low-voltage side conversion circuit.

[0061] Furthermore, this high-voltage side conversion circuit has no internal phase shift angle, and its AC side outputs a square wave voltage that is symmetrical in both positive and negative directions.

[0062] S103 generates and outputs drive signals for each switching tube in a single-stage three-port magnetic integration topology based on the control parameters.

[0063] These control parameters allow the corresponding PWM (pulse width modulation) algorithms to generate drive signals for each circuit, which will not be explained again here.

[0064] In actual applications, in this single-stage three-port magnetic integration topology AC-side conversion circuit, within each half-bridge arm, the switching tube whose flywheel diode anode points to the AC-side high-voltage terminal of the single-stage three-port magnetic integration topology has a constantly ON drive signal, while the switching tube whose flywheel diode anode points to the AC-side low-voltage terminal of the single-stage three-port magnetic integration topology has a complementary high-frequency ON / OFF drive signal with a duty cycle of 50%.

[0065] In this high-voltage side conversion circuit, the switching tubes of the half-bridge arm are switched on complementaryally, with a duty cycle of 50%, and the frequency is the same as that of the high-frequency switching tube in the AC side conversion circuit. A positive and negative symmetrical square wave voltage is generated at the midpoint of its bridge arm.

[0066] If this low-voltage side conversion circuit is a full-bridge circuit, the switching tubes of its half-bridge arm are switched on complementaryly, with a duty cycle of 50%, and the frequency is the same as that of the high-frequency switching tubes of the AC side conversion circuit. The midpoint of the bridge arm generates a three-level voltage with a positive and negative symmetrical square wave voltage or zero voltage according to the voltage relationship between the high-voltage and low-voltage sides. If this low-voltage side conversion circuit includes a cascaded full-wave rectifier circuit and a step-down circuit, the on and off times of the full-wave rectifier switching tube are in phase with the switching tubes in the high-voltage side conversion circuit, and control of the low-voltage output voltage is achieved by changing the duty cycle of the switching tubes in the step-down circuit.

[0067] By changing the phase angle of three types of in-circuit switching tubes, power transmission between the three ports of this single-stage three-port magnetic integration topology can be achieved.

[0068] The drive logic will be explained in detail below using the single-stage three-port charger topology for a single-phase power grid shown in Figure 9 as an example. Referring to Figure 9, the AC side is connected to single-phase electricity, and the AC side conversion circuit has a full-bridge structure. In one half-bridge arm, switching tubes S1 and S2 are connected back-to-back to form one bidirectional switch, and switching tubes S3 and S4 are connected back-to-back to form another bidirectional switch. The other half-bridge arm is the same. The high-voltage side conversion circuit has a full-bridge structure, with one half-bridge arm containing switching tubes Q1 and Q2, and the other half-bridge arm containing switching tubes Q3 and Q4. The low-voltage side conversion circuit has a full-bridge structure, with one half-bridge arm containing switching tubes M1 and M2, and the other half-bridge arm containing switching tubes M3 and M4. The first impedance Z1 and the third impedance Z3 are single inductors, or integrated inductors or leakage inductors of transformer T. The second impedance Z2 is a large capacitor, acting as a DC isolation, and its voltage across it is small and does not change much, so it can be considered a short circuit during analysis.

[0069] When the power grid voltage LN is positive, the anodes of the flywheel diodes of switching tubes S2 and S4 point to the L terminal, so switching tubes S2 and S4 remain constantly driven on, and the anodes of the flywheel diodes of switching tubes S1 and S3 point to the N terminal, so switching tubes S1 and S3 switch on and off at high frequencies. When the power grid voltage LN is negative, switching tubes S2 and S4 switch on and off at high frequencies, and switching tubes S1 and S3 remain constantly driven on.

[0070] When the power grid voltage LN is positive, there is an α-angle phase difference (i.e., the first angular phase difference described above) between the drive signals of switching tubes S1 and Q1, a β-angle phase difference (i.e., the second angular phase difference described above) between the drive signals of switching tubes S1 and M1, a γ-angle phase difference (i.e., the third angular phase difference described above) between the drive signals of switching tubes Q1 and M1, and the drive signal of switching tube M1 leads the drive signal of switching tube M4 by a δ-angle (i.e., the inward phase shift angle described above). By adjusting the α, β, and γ angles, energy control between the three ports of this single-stage three-port magnetic integration topology can be achieved. Simultaneously, by adjusting the δ-angle, the effective current on the transformer T winding can be reduced when transmitting the same power, reducing the conduction loss between the transformer T and the power tubes, thereby increasing the efficiency of the charger. The corresponding drive signal logic when the power grid voltage LN is positive is shown in Figure 10. Here, VCD is the midpoint voltage of the bridge arm of the high-voltage side conversion circuit (i.e., the AC side voltage, the voltage between points C and D shown in Figure 9), VEF is the midpoint voltage of the bridge arm of the low-voltage side conversion circuit (i.e., the AC side voltage, the voltage between points E and F shown in Figure 9), and VAN is the voltage difference between the AC side N line and the midpoint of the corresponding half-bridge arm in the AC side conversion circuit (midpoint A of the half-bridge arm where switching tubes S1 to S4 are located, as shown in Figure 9).

[0071] As can be seen, the midpoint voltage VCD of the high-voltage side conversion circuit bridge arm is the ± high-voltage DC side HV voltage, and when the second impedance Z2 is small, the transformer T winding port voltage to which the high-voltage side conversion circuit is connected approximates the midpoint voltage of the high-voltage side conversion circuit bridge arm. Therefore, the port voltage waveforms of the other windings of the transformer T are also positive and negative square wave voltages, and the ratio between their amplitude and the transformer T winding port voltage amplitude to which the high-voltage side conversion circuit is connected is the turns ratio of the corresponding windings. By controlling the corresponding drive signal angle, the corresponding positive and negative square wave voltages are converted into port voltages, thereby achieving control of the magnitude and direction of power.

[0072] Furthermore, when the power grid voltage LN is negative, switching tubes S2 and S4 switch on and off at high frequencies, there is an α-angle phase difference (i.e., the first angular phase difference described above) between the drive signals of switching tube S4 and Q1, and a β-angle phase difference (i.e., the second angular phase difference described above) between the drive signals of switching tube S4 and M1, and switching tubes S1 and S3 remain constantly driven on. The drive logic is similar to that when the power grid voltage LN is positive and will not be explained or shown in detail here.

[0073] Figure 11 shows a single-stage, three-port charger topology for a three-phase power grid. Its drive logic can be inferred and will not be explained again here. The drive logic for any other arbitrary circuit structure will also not be explained individually. In all cases, by controlling the phase angle of the power devices between different ports, the magnitude and direction of power can be controlled, reducing control complexity.

[0074] Identical and similar parts between the embodiments in this specification may be referenced to one another, while each embodiment focuses on the differences from the others. In particular, the descriptions of systems or system embodiments are relatively simple, as they are essentially similar to the method embodiments, and relevant points can be referred to in the partial descriptions of the method embodiments. The systems and system embodiments described above are merely schematic; the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, may be located in one place, or may be distributed across multiple network elements. Some or all of the modules can be selected as needed to achieve the objectives of this embodiment. Those skilled in the art will be able to understand and implement it without creative effort.

[0075] Those skilled in the art will further recognize that the units and algorithmic steps of each example described in relation to the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the above description has provided a functionally general description of the configuration and steps of each example. Whether these functions are performed in hardware or software depends on the specific application of the technical proposal and the design constraints. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the invention.

[0076] With respect to the above description of the disclosed embodiments, the features described in each embodiment herein may be substituted or combined with each other so that a person skilled in the art can implement or use the present invention. Various modifications to these embodiments will be obvious to a person skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the invention. Accordingly, the present invention is not limited to these embodiments shown herein, but is applicable to the broadest scope that is consistent with the principles and novel features disclosed herein.

Claims

1. This is a single-stage, three-port magnetic integration topology, It includes a transformer, an AC-side conversion circuit, a high-voltage-side conversion circuit, and a low-voltage-side conversion circuit. One side of the AC-side conversion circuit is used as the AC side of the single-stage three-port magnetic integration topology. The other side of the AC-side conversion circuit is connected to the primary winding of the transformer. The AC side of the high-voltage conversion circuit is connected to one of the secondary windings of the transformer. The DC side of the high-voltage side conversion circuit is used as the high-voltage DC side of the single-stage three-port magnetic integration topology. The AC side of the low-voltage conversion circuit is connected to the other secondary windings of the transformer. The DC side of the low-voltage side conversion circuit is used as the low-voltage DC side of the single-stage three-port magnetic integration topology. The AC-side conversion circuit is a matrix conversion structure for realizing voltage polarity conversion processing and power factor correction functions for the AC side of the single-stage three-port magnetic integration topology. The single-stage three-port magnetic integration topology further includes a first impedance, a second impedance, and a third impedance. The first impedance and the primary winding are connected in series to the corresponding side of the AC side conversion circuit. The secondary winding corresponding to the second impedance is connected in series with the AC side of the high-voltage side conversion circuit. The secondary winding corresponding to the third impedance is connected in series with the AC side of the low-voltage side conversion circuit. At the switching frequency of the single-stage three-port magnetic integration topology, the impedance value of the second impedance is smaller than the impedance value of the first impedance and the impedance value of the third impedance, and the difference between the impedance value of either the first impedance or the third impedance and the impedance value of the second impedance is greater than a preset threshold. A single-stage, three-port magnetic integration topology characterized by the following:

2. The matrix conversion structure is a three-phase structure, a full-bridge structure, or a half-bridge structure. The single-stage three-port magnetic integration topology according to feature 1.

3. The controlled half-bridge arm in the AC-side conversion circuit includes two bidirectional switches connected in series, and the bidirectional switches include two switching tubes connected in reverse series. When the matrix conversion structure is a three-phase structure or a full-bridge structure, a corresponding filter capacitor is further installed between each AC-side phase of the single-stage three-port magnetic integration topology. If the matrix conversion structure is a half-bridge structure, the AC-side conversion circuit further includes two filter capacitors connected in series, the connection point in series is used to connect the primary winding, and both ends of the series connection are connected in parallel with the half-bridge arm to the AC side of the single-stage three-port magnetic integration topology. The single-stage three-port magnetic integration topology according to feature 2.

4. The high-voltage side conversion circuit is either a full-bridge circuit or a half-bridge circuit. The single-stage three-port magnetic integration topology according to feature 1.

5. The low-voltage conversion circuit is a full-bridge circuit, or a cascaded full-wave rectifier circuit and a step-down circuit. The single-stage three-port magnetic integration topology according to feature 1.

6. The impedance value of the first impedance is zero, or the first impedance is at least one of an inductor and a capacitor. The impedance value of the aforementioned second impedance is zero, or the aforementioned second impedance is at least one of an inductor and a capacitor. The impedance value of the aforementioned third impedance is zero, or the aforementioned third impedance is at least one of an inductor and a capacitor. The single-stage three-port magnetic integration topology according to feature 1.

7. The impedance value of the second impedance is zero, or the second impedance is a capacitor with a capacitance greater than a preset capacitance. The single-stage three-port magnetic integration topology according to feature 6.

8. The inductors in the first impedance and the third impedance are single inductors, or integrated inductors or leakage inductors of the transformer. The single-stage three-port magnetic integration topology according to feature 6.

9. It is an in-car charger, A controller and a single-stage three-port magnetic integration topology according to any one of claims 1 to 8, The single-stage three-port magnetic integration topology is controlled by the controller. An in-car charger characterized by the following features.

10. A control method for an in-vehicle charger applied to the controller of the in-vehicle charger described in claim 9, The steps include: obtaining detection parameters for the single-stage three-port magnetic integration topology in the in-vehicle charger and determining the power transmission direction required for the single-stage three-port magnetic integration topology; A step of determining the control parameters of the single-stage three-port magnetic integration topology based on the detection parameters and the power transmission direction, wherein the control parameters include an outward phase shift angle and the switching frequency, Based on the control parameters, the steps include generating and outputting drive signals for each switching tube in the single-stage three-port magnetic integration topology, A method characterized by including the following.

11. The outward phase shift angle is, in the single-stage three-port magnetic integration topology, A first angular phase difference exists between the drive signals of the AC-side conversion circuit and the high-voltage-side conversion circuit, A second angular phase difference exists between the drive signals of the AC-side conversion circuit and the low-voltage-side conversion circuit, A third angular phase difference exists between the drive signals of the high-voltage side conversion circuit and the low-voltage side conversion circuit, A control method for an in-vehicle charger according to claim 10, characterized by including the following:

12. When power is transmitted from the AC side to the high-voltage DC side and the low-voltage DC side of the single-stage three-port magnetic integration topology, both the first angular phase difference and the second angular phase difference are greater than zero. When power is transmitted from the high-voltage DC side to the low-voltage DC side, the third angular phase difference is greater than zero, and the drive signal of the AC side conversion circuit is off. When power is transmitted from the high-voltage DC side to the AC side and the low-voltage DC side, the first angular phase difference is less than zero, and the third angular phase difference is greater than zero. When power is transmitted from the low-voltage DC side to the high-voltage DC side, the third angular phase difference is less than zero, and the drive signal of the AC side conversion circuit is off. The control method for an in-vehicle charger according to feature 11.

13. When the low-voltage side conversion circuit in the single-stage three-port magnetic integration topology is a full-bridge circuit, the control parameters further include the inward phase shift angle of the low-voltage side conversion circuit. The control method for an in-vehicle charger according to feature 10.

14. The aforementioned high-voltage side conversion circuit has no inward phase shift angle. The control method for an in-vehicle charger according to feature 10.

15. In the AC-side conversion circuit of the single-stage three-port magnetic integration topology, each half-bridge arm contains: A switching tube in which the anode of a flywheel diode points to the AC-side high-voltage terminal of the single-stage three-port magnetic integration topology has a drive signal that is always on. A switching tube in which the anode of a flywheel diode points to the AC-side low-voltage terminal of the single-stage three-port magnetic integration topology has a drive signal that is a complementary high-frequency on / off signal. The control method for an in-vehicle charger according to feature 10.

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