Bidirectional conversion circuit, control method and related equipment thereof

Abstract

The invention relates to the technical field of power electronic conversion, in particular to a bidirectional conversion circuit, a control method and related equipment, and the bidirectional conversion circuit comprises a transformer, a primary side coil is connected with the first end of a conversion unit, and a secondary side coil is connected with a coupling inductor; the conversion unit is used for converting a direct-current signal and an alternating-current signal, and a second end of the conversion unit is used as a primary side interface; a pair of same-side terminals of the coupling inductor are connected with the secondary side coil, the other pair of same-side terminals of the coupling inductor are respectively connected with the first end of the gating switch unit, and the second end of the gating switch unit is used as a secondary side interface; the bidirectional conversion circuit provided by the invention can realize bidirectional power transmission without adapting to more drive circuits, thereby reducing the circuit area and the system complexity.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power electronic conversion, and in particular to a bidirectional conversion circuit, a control method and related equipment. Background Art

[0002] With the rapid development of new energy vehicles and the updating and iteration of their product technologies, new energy vehicles are required to have more and more functions.

[0003] For on-board chargers, unidirectional power transmission sometimes cannot meet the needs of different applications. Topologies that support bidirectional transmission are more suitable for the current market. Summary of the invention

[0004] The embodiments of the present disclosure provide a bidirectional conversion circuit, a control method and related devices thereof, which can realize bidirectional power transmission without adapting more driving circuits, thereby reducing circuit area and system complexity.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present disclosure provides a bidirectional conversion circuit, including: a transformer, a primary coil connected to the first end of a conversion unit, and a secondary coil connected to a coupled inductor; the conversion unit is used for converting DC signals and AC signals, and the second end of the conversion unit is used as a primary interface; a coupled inductor, a pair of same-side terminals connected to the secondary coil, and another pair of same-side terminals are respectively connected to the first end of a gate switch unit, and the second end of the gate switch unit is used as a secondary interface.

[0006] In some embodiments, a pair of same-side terminals of the coupled inductor are respectively connected to two side terminals of the secondary coil, and a center tap of the secondary coil is grounded.

[0007] In some embodiments, a pair of same-side terminals of the coupled inductor are connected to a center tap of the secondary coil, and two side terminals of the secondary coil are grounded respectively.

[0008] In some embodiments, the coupling coefficient of the coupled inductor is greater than 0.99.

[0009] In some embodiments, the conversion unit includes: a first busbar and a second busbar, which are respectively connected to the primary interface; a first switch, whose first end is connected to the first busbar, and whose second end is connected to the first end of the primary coil; a second switch, whose first end is connected to the second end of the first switch, and whose second end is connected to the second busbar; a third switch, whose first end is connected to the first busbar, and whose second end is connected to the second end of the primary coil; and a fourth switch, whose first end is connected to the second end of the third switch, and whose second end is connected to the second busbar.

[0010] In some embodiments, the conversion unit further includes: a first capacitor and a first inductor, which are arranged in series in a connection path between the first switch and the primary coil; and a second inductor, which is connected to both ends of the primary coil.

[0011] In some embodiments, the bidirectional conversion circuit further includes: a second capacitor, which is arranged in parallel at two ends of the secondary side interface.

[0012] In some embodiments, the gating switch unit includes a first gating switch and a second gating switch, another pair of same-side terminals of the coupled inductor are respectively connected to the first end of the first gating switch and the first end of the second gating switch, the second end of the first gating switch is connected to the second end of the second gating switch and serves as a secondary side interface.

[0013] In some embodiments, the bidirectional conversion circuit further includes: a first feedback loop configured to adjust the on-time of the conversion unit based on a first comparison result between the output voltage of the secondary interface and the first reference voltage.

[0014] In some embodiments, the bidirectional conversion circuit further includes: a second feedback loop configured to adjust the on-time of the gate switch unit based on a second comparison result between the output voltage of the primary interface and the second reference voltage.

[0015] In some embodiments, the first feedback loop is further configured to obtain a third comparison result between the output current of the secondary interface and the first reference current, and adjust the on-time of the conversion unit based on the smaller value of the first comparison result and the third comparison result.

[0016] In some embodiments, the second feedback loop is further configured to obtain a fourth comparison result between the output current of the primary interface and the second reference current, and adjust the on-time of the gate switch unit based on the smaller value of the second comparison result and the fourth comparison result.

[0017] According to the second aspect of the present disclosure, a control method is provided, which is applied to the above-mentioned bidirectional conversion circuit, including: detecting the output voltage of the bidirectional conversion circuit; obtaining the voltage difference between the output voltage and the corresponding reference voltage; and adjusting the value of the output voltage based on the voltage difference so that the output voltage approaches the reference voltage.

[0018] In some embodiments, the output voltage includes one of a primary output voltage or a secondary output voltage, and the reference voltages corresponding to the primary output voltage and the secondary output voltage are different.

[0019] In some embodiments, if the output voltage is a primary output voltage, the method for adjusting the value of the output voltage based on the voltage difference includes: adjusting a duty cycle of the gate switch unit.

[0020] In some embodiments, if the output voltage is a secondary side output voltage, the method for adjusting the value of the output voltage based on the voltage difference includes: adjusting the duty cycle of each gate switch in the gate unit.

[0021] In some embodiments, the control method also includes: detecting the output current of the two-wire conversion circuit; obtaining the current difference between the output current and the corresponding reference current; the method for adjusting the output voltage value based on the voltage difference includes: adjusting the output voltage value based on the minimum value of the voltage difference and the current difference.

[0022] In some embodiments, the output current includes one of a primary output current and a secondary output current, and reference voltages corresponding to the primary output current and the secondary output current are different.

[0023] According to a third aspect of the present disclosure, a controller is provided, wherein a processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program to implement the control method mentioned above.

[0024] According to a fourth aspect of the present disclosure, a computer-readable storage medium is provided, and a computer program is loaded by a processor to execute the control method mentioned above.

[0025] According to a fifth aspect of the present disclosure, a vehicle-mounted power supply is provided, wherein the constituent circuit of the vehicle-mounted power supply includes the bidirectional conversion circuit as mentioned above.

[0026] According to a sixth aspect of the present disclosure, a vehicle is provided, comprising the bidirectional conversion circuit as mentioned above, or the on-board power supply as mentioned above, or the controller as mentioned above, or the computer-readable storage medium as mentioned above.

[0027] The bidirectional conversion circuit of the disclosed embodiment, due to the setting of the coupled inductor, the coupled inductor acts as an energy storage element, which can realize the periodic storage and release of energy, thereby achieving the effect of controlling the output voltage. In addition, the direction of the inductor current of the coupled inductor can also be controlled by the switch timing, ultimately achieving the effect of controlling the direction of energy transmission. Compared with independent inductors, the coupled inductor has a faster commutation speed and can achieve a greater circuit gain; in addition, the bidirectional conversion circuit provided in this embodiment only includes two switching devices in the circuit while realizing bidirectional power transmission, and there is no need to adapt more driving circuits, thereby reducing the circuit area and system complexity.

[0028] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0030] Figure 1 A schematic diagram of a common isolated DC / DC circuit topology structure provided in an embodiment of the present disclosure;

[0031] Figure 2 The embodiments of the present disclosure provide Figure 1 An example of the operating timing of the topology shown;

[0032] Figure 3 A schematic diagram of the structure of a bidirectional conversion circuit provided by an embodiment of the present disclosure;

[0033] Figure 4 A schematic diagram of the structure of another bidirectional conversion circuit provided by an embodiment of the present disclosure;

[0034] Figure 5 A schematic diagram of a specific bidirectional conversion circuit provided in an embodiment of the present disclosure;

[0035] Figure 6 The embodiments of the present disclosure provide Figure 5 Timing example of forward power transfer for the topology shown;

[0036] Figure 7 The embodiments of the present disclosure provide Figure 5 Timing example of reverse power transfer for the topology shown;

[0037] Figure 8 A schematic diagram of the principle of a first feedback loop provided in an embodiment of the present disclosure;

[0038] Fig. 9 A schematic diagram of the principle of a second feedback loop provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present disclosure will be described clearly and completely below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0040] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0041] In this disclosure, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described in this disclosure as "exemplary" is not necessarily to be construed as being preferred or advantageous over other embodiments. The following description is given to enable any person skilled in the art to implement and use the invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the invention can be implemented without using these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in this disclosure.

[0042] At the same time, the present disclosure uses specific words to describe the embodiments of the present disclosure. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present disclosure. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present disclosure may be appropriately combined.

[0043] Similarly, it should be noted that in order to simplify the description of the disclosure and thus help understand one or more application embodiments, in the above description of the embodiments of the disclosure, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of the disclosure are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0044] In some embodiments, numbers are used to describe the number of components and attributes. It should be understood that such numbers used to describe the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, numerical parameters should consider specifying significant digits and adopting a general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present disclosure are approximate values, in specific embodiments, such numerical values ​​are set as accurately as possible within the feasible range.

[0045] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this disclosure are hereby incorporated by reference in their entirety, except for application history documents that are inconsistent with or conflicting with the content of this disclosure, and documents that limit the broadest scope of the claims of this disclosure (currently or later attached to this disclosure). It should be noted that if the descriptions, definitions, and / or use of terms in the accompanying materials of this disclosure are inconsistent or conflicting with the examples of this disclosure, the descriptions, definitions, and / or use of terms in this disclosure shall prevail.

[0046] refer to Figure 1 , Figure 1 This is a schematic diagram of a common isolated DC / DC circuit topology. Figure 1 The topology shown is particularly common in automotive power supplies and power bricks.

[0047] Specifically, Figure 1 The topology shown is a traditional full-bridge hard-switching circuit, and four switching devices (Q1, Q2, Q3 and Q4) are used on the primary side to form a full bridge; wherein the switching devices can be MOSFET (Metal-Oxide-SemiconductorField-Effect Transistor), IGBT (Insulated GateBipolar Transistor) and other components, and the full bridge is composed of two half-bridges, and the switch nodes of the two half-bridges are respectively connected to the two ends of the primary winding of the transformer; the secondary winding of the transformer adopts a center-tapped structure, the center tap is connected to the output inductor, and the two ends of the secondary winding are grounded through synchronous rectification switching devices (SR1 and SR2); wherein the synchronous rectification switching devices can be MOSFET, IGBT and other components.

[0048] Figure 1 The topology shown achieves the purpose of controlling and adjusting the output voltage by adjusting the duty cycle of the primary switching device. Specifically, the higher the duty cycle of the primary switching device, the longer the output time at the output end is, and the effective value of the output voltage increases; the lower the duty cycle of the primary switching device, the shorter the output time at the output end is, and the effective value of the output voltage decreases.

[0049] It should be noted that Figure 1 In the topology shown, a transformer is used to isolate (separate) the input path from the output path. The presence of the transformer is due to system safety and related regulatory requirements. This topology is called an isolated converter topology.

[0050] refer to Figure 1 and Figure 2 , Figure 2 for Figure 1 An example of the operating timing of the topology shown; wherein Q1 and Q4 are turned on simultaneously as a pair of diagonal switches, Q2 and Q3 are turned on simultaneously as a pair of diagonal switches, VPRI is the primary voltage of the transformer, IPRI is the primary current of the transformer, and SR1 and SR2 are two switches for secondary synchronous rectification.

[0051] Specifically, in the T0-T1 stage, when Q1 and Q2 are turned on at the same time, the primary power supply is directly loaded on both ends of the primary winding, the primary voltage VPRI is positive, the primary power supply charges the primary winding, the primary current IPRI gradually increases, SR1 is turned on, and the secondary positive end forms a loop through the secondary winding, SR1 and the secondary negative pole to output the induced current generated by the transformer through the secondary positive end and the secondary negative end. In the T1-T2 stage, Q1-Q4 are closed at the same time, the circuit is not turned on, the primary voltage VPRI is 0, and because the primary winding acts as an inductor, the circuit current cannot change suddenly, and the primary current IPRI gradually decreases. In the T2-T3 stage, when Q2 and Q3 are turned on at the same time, the primary power supply is reversely loaded on both ends of the primary winding, the primary voltage VPRI is negative, the primary power supply charges the primary winding in reverse phase, the primary current IPRI quickly reverses phase and gradually increases, SR2 is turned on, and the secondary positive end forms a loop through the secondary winding, SR2 and the secondary negative pole to output the induced current generated by the transformer through the secondary positive end and the secondary negative end. In the T3-T4 stage, Q1-Q4 are closed at the same time, the circuit is not conducting, the primary voltage VPRI is 0, and since the primary winding acts as an inductor, the circuit current cannot change suddenly, and the primary current IPRI gradually decreases. The subsequent stages implement the cycle based on the description of the T0-T4 stage, which will not be repeated in this embodiment.

[0052] Combining the above discussion, we can see that Figure 1 The center-tapped rectifier circuit on the secondary side of the topology shown works in a synchronous rectification state. Figure 1 The power transmission direction of the topology shown is unidirectional (from the full-bridge circuit to the center-tap circuit). However, unidirectional power transmission sometimes cannot meet the needs of different applications, and topologies that support bidirectional transmission are proposed; for example, the secondary center-tap rectifier circuit is replaced with the same full-bridge topology as the primary. Figure 1 In the topology shown, the number of switching devices and supporting driving circuits on the secondary side is doubled, which significantly increases the circuit cost and system complexity.

[0053] Based on this, an embodiment of the present disclosure provides an isolation circuit that can achieve bidirectional power transmission without adapting more driving circuits, thereby reducing circuit area and system complexity.

[0054] refer to Figure 3 and Figure 4 , Figure 3A schematic diagram of a bidirectional conversion circuit provided in this embodiment. Figure 4 This is a schematic diagram of the structure of another bidirectional conversion circuit provided in this embodiment. The bidirectional conversion circuit 100 provided in this embodiment includes: a transformer L1, a conversion unit 101, a coupling inductor L_cp, and a gate switch unit 30.

[0055] Among them, the primary coil W1 of the transformer L1 is connected to the first end of the conversion unit 101, and the secondary coil W2 of the transformer L1 is connected to the coupling inductor L_cp; the conversion unit 101 is used for converting DC signals and AC signals, and the second end of the conversion unit 101 is used as the primary interface A; a pair of same-side terminals of the coupling inductor L_cp are connected to the secondary coil W2, and the other pair of same-side terminals are respectively connected to the first end of the selection switch unit 30; the second end of the selection switch unit 30 is used as the secondary interface B.

[0056] It should be noted that when power is transmitted from the primary side to the secondary side, the primary side interface A can be used to connect the power supply, and the secondary side interface B can be used to connect the load or power supply; when power is transmitted from the secondary side to the primary side, the secondary side interface B can be used to connect the power supply, and the primary side interface A can be used to connect the load or power supply.

[0057] For the bidirectional conversion circuit provided in this embodiment, due to the setting of the coupled inductor, the coupled inductor acts as an energy storage element, which can realize the periodic storage and release of energy, thereby achieving the effect of controlling the output voltage. And the direction of the inductor current of the coupled inductor can also be controlled by the switch timing, ultimately achieving the effect of controlling the direction of energy transmission. Compared with independent inductors, the commutation speed of coupled inductors is faster, and a greater circuit gain can be achieved; in addition, the bidirectional conversion circuit provided in this embodiment, while realizing bidirectional power transmission, only includes two switching devices in the circuit, and there is no need to adapt more driving circuits, thereby reducing the circuit area and system complexity.

[0058] In some embodiments, the gating switch unit 30 includes a first gating switch K1 and a second gating switch K2, wherein another pair of same-side terminals of the coupled inductor L_cp are respectively connected to the first end of the first gating switch K1 and the first end of the second gating switch K2; the second end of the first gating switch K1 is connected to the second end of the second gating switch K2 and serves as a secondary side interface B.

[0059] In some embodiments, reference Figure 3 A pair of same-side terminals of the coupling inductor L_cp are respectively connected to two side terminals of the secondary coil W2, and a center tap of the secondary coil W2 is grounded.

[0060] In some embodiments, reference Figure 4 A pair of same-side terminals of the coupling inductor L_cp are connected to the center tap of the secondary coil W2, and the two side terminals of the secondary coil W2 are grounded respectively.

[0061] It should be noted that the bidirectional conversion circuit 100 provided in this embodiment also includes other devices for optimizing waveform and transmission power. Figure 3 and Figure 4 The example does not reflect these components, which does not mean that the bidirectional conversion circuit 100 provided in this embodiment does not include these components; in addition, the subsequent description of this embodiment Figure 3 The structure is used as an example to supplement and illustrate, and those skilled in the art can replace the corresponding features with Figure 4 In the example shown.

[0062] In some embodiments, the coupled inductor L_cp is a forward coupled inductor, and a coupling coefficient of the coupled inductor L_cp is greater than 0.99, so that the coupled inductor forms a custom transformer.

[0063] refer to Figure 5 , Figure 5 A schematic diagram of a specific bidirectional conversion circuit provided in this embodiment. In some embodiments, the primary interface A is used to connect the second power supply Vo2, and the secondary interface B is used to connect the first power supply Vo1; wherein the first power supply Vo1 and the second power supply Vo2 are both DC power supplies. When power is transmitted in the forward direction, the second power supply Vo2 charges the first power supply Vo1; when power is transmitted in the reverse direction, the first power supply Vo1 charges the second power supply Vo2.

[0064] Continue to refer Figure 5 In some embodiments, the conversion unit 101 includes: a first bus, a second bus, a first switch Q1, a second switch Q2, a third switch Q3 and a fourth switch Q4.

[0065] Among them, the first busbar and the second busbar are respectively connected to the primary interface A; the first end of the first switch Q1 is connected to the first busbar, and the second end is connected to the first end of the primary coil W1; the first end of the second switch Q2 is connected to the second end of the first switch Q1, and the second end is connected to the second busbar; the first end of the third switch Q3 is connected to the first busbar, and the second end is connected to the second end of the primary coil W1; the first end of the fourth switch Q4 is connected to the second end of the third switch Q3, and the second end is connected to the second busbar.

[0066] Specifically, the first busbar is connected to the positive electrode of the second power source Vo2, and the second busbar is connected to the negative electrode of the second power source Vo2; the first switch Q1 and the second switch Q2 form a bridge arm, the midpoint of which is connected to the first end of the primary coil W1; the third switch Q3 and the fourth switch Q4 form a bridge arm, the midpoint of which is connected to the second end of the primary coil W1. The first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 are controlled by a controller, and the controller realizes the conversion of DC signals and AC signals, as well as the size of the output signal by controlling the conduction of the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4.

[0067] In some embodiments, reference Figure 5 , the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 are configured based on MOS tubes. In addition, in some embodiments, the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 configured based on MOS tubes all have a parasitic diode. Taking the first switch Q1 as an example, the positive electrode of the parasitic diode is connected to the first end of the first switch Q1, and the negative electrode of the parasitic diode is connected to the second end of the first switch Q1. The connection relationship of the parasitic diodes corresponding to the second switch Q2, the third switch Q3 and the fourth switch Q4 is the same as that of the first switch Q1, and will not be repeated in this embodiment.

[0068] In some embodiments, the conversion unit 101 further includes: a first capacitor C0, a first inductor L0, and a second inductor Lm; wherein the first capacitor C0 and the first inductor L0 are arranged in series in the connection path between the first switch Q1 and the primary coil W1, so as to cooperate with the bridge arm formed by the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 to form a boost circuit. The second inductor Lm is connected to both ends of the primary coil W1, and the second inductor Lm is used as a filter inductor to stabilize the primary current.

[0069] It should be noted that the first inductor L0 may be the leakage inductance of the primary coil W1 of the transformer L1 , or may be an external inductor.

[0070] In some embodiments, the bidirectional conversion circuit 100 further includes a second capacitor Cm, and the second capacitor Cm is connected in parallel at two ends of the secondary interface B.

[0071] Specifically, the second end of the first selection switch K1 and the second end of the second selection switch K2 are connected to the first end of the second capacitor Cm and to the positive electrode of the secondary interface B; the second end of the second capacitor Cm and the negative electrode of the secondary interface B are grounded.

[0072] In some embodiments, reference Figure 5, the first selection switch K1 and the second selection switch K2 are arranged based on MOS tubes. In addition, in some embodiments, the first selection switch K1 and the second selection switch K2 arranged based on MOS tubes both have a parasitic diode. Taking the first selection switch K1 as an example, the positive electrode of the parasitic diode is connected to the second end of the first selection switch K1, and the negative electrode of the parasitic diode is connected to the first end of the first selection switch K1. The connection relationship of the parasitic diode corresponding to the second selection switch K2 is the same as that of the first selection switch K1, and will not be repeated in this embodiment.

[0073] refer to Figure 6 , Figure 6 The embodiment provided Figure 5 The timing example of the forward power transmission of the topology shown; specifically, in the T0-T1 stage, when Q1 and Q2 are turned on at the same time, the second capacitor Vo2 is directly loaded on both ends of the primary coil; the first selection switch K1 is turned on, the positive pole of the secondary side is grounded through K1 and the secondary coil W2 to form a loop, and the negative pole of the secondary side is grounded to transmit the induced current generated by the transformer to the positive pole of the secondary side. In the T1-T2 stage, Q1-Q4 are closed at the same time, and the circuit is not conducting. In the T2-T3 stage, when Q2 and Q3 are turned on at the same time, the second power supply Vo2 is reversely loaded on both ends of the primary coil; the second selection switch K2 is turned on, the positive pole of the secondary side is grounded through the K2 secondary coil W2 to form a loop, and the negative pole of the secondary side is grounded to transmit the induced current generated by the transformer to the positive pole of the secondary side. In the T3-T4 stage, Q1-Q4 are closed at the same time, and the circuit is not conducting. The subsequent stages are based on the description of the T0-T4 stage to realize the cycle, and this embodiment will not be repeated.

[0074] Among them, the duty cycle D1 of the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 is adjustable in the range of 0 to 0.5. The larger the duty cycle D1, the larger the secondary output voltage; the on-off actions of the first switch Q1, the fourth switch Q4 and the second switch Q2, the third switch Q3 are opposite; the first selection switch K1 and the second selection switch K2 work in the synchronous rectification state, and the duty cycle follows the duty cycle D1 of the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4. In this state, the circuit is consistent with the wave generation mode of the traditional full-bridge hard switch circuit.

[0075] refer to Figure 7 , Figure 7 The embodiment provided Figure 5The timing example of reverse power transmission of the topology shown; specifically, in the T0-T1 stage, K1 is turned on, the positive pole of the secondary side is grounded through K1 and the secondary coil W2 to form a loop, and the negative pole of the secondary side is grounded to load the first power supply Vo1 to both ends of the secondary coil, and the switch tube in the conversion unit 101 is rectified by the parasitic diode to transmit the induced current generated by the transformer to the positive pole of the primary side; in the T1-T2 stage, K1 and K2 are closed at the same time, and the circuit is not conducting. In the T2-T3 stage, K2 is turned on, the positive pole of the secondary side is grounded through K2 and the secondary coil W2 to form a loop, and the negative pole of the secondary side is grounded to load the first power supply Vo1 to both ends of the secondary coil, and the switch tube in the conversion unit 101 is rectified by the parasitic diode to transmit the induced current generated by the transformer to the positive pole of the primary side; in the T3-T4 stage, K1 and K2 are closed at the same time, and the circuit is not conducting. The subsequent stages are based on the description of the T0-T4 stage to realize the cycle, and this embodiment will not be repeated.

[0076] Among them, the duty cycle D2 of the first gate switch tube K1 and the second gate switch tube K2 varies in the range of 0 to 1, and the larger the duty cycle D2, the larger the primary output voltage. In order to prevent the primary circuit from working abnormally, the drive circuit corresponding to the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 can be turned off, and only the parasitic diodes corresponding to the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 are used for rectification; in some embodiments, the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 can also be driven by the drive circuit for rectification.

[0077] refer to Figure 8 , Figure 8 A schematic diagram of the principle of the first feedback loop provided for this embodiment; in some embodiments, the bidirectional conversion circuit 100 also includes a first feedback loop, and the first feedback loop is configured to adjust the conduction time of the conversion unit 101 based on a first comparison result of the output voltage Vo1 of the secondary interface B and the first reference voltage Vo1_ref.

[0078] Specifically, the first feedback loop is used to detect the output voltage Vo1 of the secondary interface B, obtain the first voltage difference V1 between the output voltage Vo1 and the first reference voltage Vo1_ref, generate a first compensation time corresponding to the turn-on time of the conversion unit 101 based on the first voltage difference V1, and adjust the turn-on time of the conversion unit 101 based on the first compensation time.

[0079] Specifically, the first processing circuit adjusts the on-time of the conversion unit 101 based on feedback control methods such as PI, PD, and PID, wherein the adjustment of the on-time of the conversion unit 101 can be embodied as adjusting the duty cycle D1 of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4. Based on the foregoing discussion, it can be seen that adjusting the duty cycle D1 can adjust the output voltage Vo1 of the secondary interface B so that the output voltage Vo1 of the secondary interface B approaches the first reference voltage Vo1_ref.

[0080] In some embodiments, the first feedback loop is further configured to obtain a third comparison result between the output current Io1 of the secondary interface B and the first reference current Io1_ref, and based on the smaller value of the first comparison result and the third comparison result, adjust the on-time of the conversion unit 101. The minimum value of the current feedback and voltage feedback control is adjusted to prevent the feedback regulation current in the current from being too large, so as to protect the circuit.

[0081] refer to Fig. 9 , Fig. 9 A schematic diagram of the principle of the second feedback loop provided for this embodiment; in some embodiments, the bidirectional conversion circuit 100 also includes a second feedback loop, and the second feedback loop is configured to adjust the conduction time of the selection switch unit 30 based on a second comparison result of the output voltage Vo2 of the primary interface A and the second reference voltage Vo2_ref.

[0082] Specifically, the second feedback loop is used to detect the output voltage Vo2 of the primary interface A, obtain the second voltage difference V2 between the output voltage Vo2 of the primary interface A and the second reference voltage Vo2_ref, generate a second compensation time corresponding to the on-time of the adjustment gate switch unit 30 based on the second voltage difference V2, and adjust the on-time of the gate switch unit 30 based on the second compensation time.

[0083] Specifically, the second processing circuit adjusts the on-time of the enabling switch unit 30 based on feedback control methods such as PI, PD, and PID, wherein the adjustment of the on-time of the enabling switch unit 30 can be embodied as adjusting the duty cycle D2 of the enabling switch unit 30. Based on the foregoing discussion, adjusting the duty cycle D2 can adjust the output voltage Vo2 of the primary interface A so that the output voltage Vo2 of the primary interface A approaches the second reference voltage Vo2_ref.

[0084] In some embodiments, the second feedback loop is further configured to obtain a fourth comparison result between the output current Io2 of the primary interface A and the second reference current Io2_ref, and based on the smaller value of the second comparison result and the fourth comparison result, adjust the on time of the gate switch unit 30. The minimum value of the current feedback and voltage feedback control is adjusted to prevent the feedback regulation current in the current from being too large, so as to protect the circuit.

[0085] In some embodiments, the first detection unit and the second detection unit may reuse the same detection unit, the first processing unit and the second processing unit may reuse the same processing unit, and the first control unit and the second control unit may be the same controller.

[0086] The bidirectional conversion circuit of the disclosed embodiment, due to the setting of the coupled inductor, the coupled inductor acts as an energy storage element, which can realize the periodic storage and release of energy, thereby achieving the effect of controlling the output voltage. In addition, the direction of the inductor current of the coupled inductor can also be controlled by the switch timing, ultimately achieving the effect of controlling the direction of energy transmission. Compared with independent inductors, the coupled inductor has a faster commutation speed and can achieve a greater circuit gain; in addition, the bidirectional conversion circuit provided in this embodiment only includes two switching devices in the circuit while realizing bidirectional power transmission, and there is no need to adapt more driving circuits, thereby reducing the circuit area and system complexity.

[0087] Another embodiment of the present disclosure also provides a control method, which is applied to the bidirectional conversion circuit provided in the above embodiment, so that the output current of the bidirectional conversion circuit approaches a preset value. Specifically, the control method includes: step S1, detecting the output voltage of the bidirectional conversion circuit; step S2, obtaining the voltage difference between the output voltage and the corresponding reference voltage; step S3, adjusting the value of the output voltage based on the voltage difference, so that the output voltage approaches the reference voltage.

[0088] For step S1 , the output voltage includes one of a primary output voltage and a secondary output voltage.

[0089] Specifically, detecting the output voltage of the bidirectional conversion circuit includes: detecting a primary output voltage or a secondary output voltage in the bidirectional conversion circuit.

[0090] For step S2, in some embodiments, the reference voltage corresponding to the primary output voltage and the secondary output voltage is the same; in other embodiments, the reference voltage corresponding to the primary output voltage and the secondary output voltage is different.

[0091] If the reference voltages corresponding to the primary output voltage and the secondary output voltage are the same, the voltage difference is directly obtained by comparing the obtained output voltage with the reference voltage.

[0092] If the reference voltages corresponding to the primary output voltage and the secondary output voltage are different, the primary output voltage is compared with the corresponding reference voltage to obtain a voltage difference, and the secondary output voltage is compared with the corresponding reference voltage to obtain a voltage difference.

[0093] For step S3, if the output voltage is the primary output voltage, the method for adjusting the value of the output voltage based on the voltage difference includes: adjusting the duty cycle of the gate switch unit.

[0094] Specifically, based on the foregoing, it can be known that adjusting the duty cycle of the gate switch unit can adjust the magnitude of the primary output voltage. By adjusting the duty cycle of the gate switch unit based on the adjustment value obtained based on the voltage difference, the primary output voltage can be made close to the reference voltage.

[0095] If the output voltage is a secondary side output voltage, the method for adjusting the value of the output voltage based on the voltage difference includes: adjusting the duty cycle of each gate switch in the gate unit.

[0096] Specifically, based on the foregoing, it can be known that adjusting the duty cycle of each gating switch can adjust the magnitude of the secondary output voltage. By adjusting the duty cycle of each gating switch based on the adjustment value obtained based on the voltage difference, the secondary output voltage can be made close to the reference voltage.

[0097] In some embodiments, before executing step S3, step S11 is further included, detecting the output current of the bidirectional conversion circuit; step S22 is to obtain the voltage difference between the output current and the corresponding reference current; in this case, step S3 is changed to adjust the output voltage value based on the minimum value of the voltage difference and the current difference. The minimum value of the current feedback and voltage feedback control is adjusted to prevent the feedback adjustment current in the current from being too large, so as to protect the circuit.

[0098] For step S11 , the output current includes one of a primary output current and a secondary output current.

[0099] Specifically, detecting the output current of the bidirectional conversion circuit includes: detecting the primary output current or the secondary output current of the bidirectional conversion circuit.

[0100] For step S22, in some embodiments, the reference current corresponding to the primary output current and the secondary output current is the same; in other embodiments, the reference current corresponding to the primary output current and the secondary output current is different.

[0101] If the reference currents corresponding to the primary output current and the secondary output current are the same, the current difference is directly obtained by comparing the obtained output current with the reference current.

[0102] If the reference currents corresponding to the primary output current and the secondary output current are different, the primary output current is compared with the corresponding reference current to obtain a current difference, and the secondary output current is compared with the corresponding reference current to obtain a current difference.

[0103] Another embodiment of the present disclosure further provides a controller, the controller includes a processor, the processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program to implement the above control method.

[0104] Another embodiment of the present disclosure further provides a computer-readable storage medium storing a computer program, which is loaded by a processor to execute the above control method.

[0105] Yet another embodiment of the present disclosure provides a vehicle-mounted power supply, wherein the constituent circuit of the vehicle-mounted power supply includes the above-mentioned bidirectional conversion circuit.

[0106] Another embodiment of the present disclosure also provides a vehicle, including the above-mentioned bidirectional conversion circuit, or includes the above-mentioned vehicle-mounted power supply, or includes the above-mentioned controller, or includes the above-mentioned computer-readable storage medium. The vehicle provided by the present disclosure can achieve bidirectional power transmission without adapting more driving circuits, thereby reducing circuit area and system complexity.

[0107] The exclusive right of the vehicle has all the beneficial effects of the above-mentioned minimum protection subject, and the disclosure will not repeat them here. The vehicle can be a fuel vehicle, a plug-in hybrid vehicle or a new energy vehicle, etc., and the disclosure does not make specific limitations on this.

[0108] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the detailed description of other embodiments above, and will not be repeated here.

[0109] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present disclosure. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and corrections to the present disclosure. Such modifications, improvements and corrections are suggested in the present disclosure, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the present disclosure.

[0110] The above is a detailed introduction to a bidirectional conversion circuit, a control method and related equipment provided by an embodiment of the present disclosure. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, it can be seen that the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A bidirectional conversion circuit, characterized in that: include: A transformer, wherein the primary coil is connected to the first end of the conversion unit, and the secondary coil is connected to the coupling inductor; The conversion unit is used for converting a DC signal and an AC signal, and the second end of the conversion unit is used as a primary side interface; The coupled inductor has a pair of same-side terminals connected to the secondary coil, and another pair of same-side terminals respectively connected to the first end of the gate switch unit, and the second end of the gate switch unit is used as a secondary interface.

2. The bidirectional conversion circuit according to claim 1, characterized in that: A pair of same-side terminals of the coupled inductor are respectively connected to two side terminals of the secondary coil, and a center tap of the secondary coil is grounded.

3. The bidirectional conversion circuit according to claim 1, characterized in that: A pair of same-side terminals of the coupled inductor are connected to a center tap of the secondary coil, and two side terminals of the secondary coil are grounded respectively.

4. The bidirectional conversion circuit according to any one of claims 1 to 3, characterized in that: The coupling coefficient of the coupled inductor is greater than 0.

99.

5. The bidirectional conversion circuit according to claim 1, characterized in that: The conversion unit comprises: A first busbar and a second busbar are connected to the primary side interface respectively; a first switch, a first end of which is connected to the first bus bar, and a second end of which is connected to the first end of the primary coil; a second switch, a first end of which is connected to the second end of the first switch, and a second end of which is connected to the second bus; a third switch, a first end of which is connected to the first busbar, and a second end of which is connected to the second end of the primary coil; A fourth switch has a first end connected to the second end of the third switch, and a second end connected to the second bus.

6. The bidirectional conversion circuit according to claim 5, characterized in that: The conversion unit also includes: A first capacitor and a first inductor are arranged in series in a connection path between the first switch and the primary coil; The second inductor is connected to two ends of the primary coil.

7. The bidirectional conversion circuit according to claim 1, characterized in that: The bidirectional conversion circuit further includes: a second capacitor, which is arranged in parallel at both ends of the secondary side interface.

8. The bidirectional conversion circuit according to claim 1, characterized in that: The gating switch unit includes a first gating switch and a second gating switch, the other pair of same-side terminals of the coupled inductor are respectively connected to the first end of the first gating switch and the first end of the second gating switch, the second end of the first gating switch is connected to the second end of the second gating switch and serves as a secondary side interface.

9. The bidirectional conversion circuit according to claim 1, characterized in that: The bidirectional conversion circuit further includes: a first feedback loop configured to adjust the on-time of the conversion unit based on a first comparison result between the output voltage of the secondary side interface and the first reference voltage.

10. The bidirectional conversion circuit according to claim 1 or 9, characterized in that: The bidirectional conversion circuit further includes: a second feedback loop configured to adjust the conduction time of the gate switch unit based on a second comparison result between the output voltage of the primary interface and the second reference voltage.

11. The bidirectional conversion circuit according to claim 9, characterized in that: The first feedback loop is further configured to obtain a third comparison result between the output current of the secondary interface and the first reference current, and adjust the on-time of the conversion unit based on a smaller value between the first comparison result and the third comparison result.

12. The bidirectional conversion circuit according to claim 10, characterized in that: The second feedback loop is further configured to obtain a fourth comparison result between the output current of the primary interface and the second reference current, and adjust the on-time of the gate switch unit based on a smaller value between the second comparison result and the fourth comparison result.

13. A control method, characterized in that: The bidirectional conversion circuit according to any one of claims 1 to 12 is characterized in that: detecting an output voltage of the bidirectional conversion circuit; Obtaining a voltage difference between the output voltage and a corresponding reference voltage; The value of the output voltage is adjusted based on the voltage difference so that the output voltage approaches the reference voltage.

14. The control method according to claim 13, characterized in that: The output voltage includes one of a primary output voltage and a secondary output voltage, and a reference voltage corresponding to the primary output voltage and the secondary output voltage is different.

15. The control method according to claim 14, characterized in that: If the output voltage is a primary output voltage, the method for adjusting the value of the output voltage based on the voltage difference includes: adjusting the duty cycle of the gate switch unit.

16. The control method according to claim 14, characterized in that: If the output voltage is a secondary side output voltage, the method for adjusting the value of the output voltage based on the voltage difference includes: adjusting the duty cycle of each gate switch in the gate unit.

17. The control method according to claim 13, characterized in that: Also includes: detecting an output current of the two-wire conversion circuit; Obtaining a current difference between the output current and a corresponding reference current; The method of adjusting the value of the output voltage based on the voltage difference includes adjusting the value of the output voltage based on a minimum value of the voltage difference and the current difference.

18. The control method according to claim 17, characterized in that: The output current includes one of a primary output current and a secondary output current, and the primary output current and the secondary output current have different reference voltages corresponding to them.

19. A controller, characterized in that: It comprises a processor, the processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program to implement the control method according to any one of claims 13 to 18.

20. A computer-readable storage medium, characterized in that: A computer program is stored, and the computer program is loaded by a processor to execute the control method according to any one of claims 13 to 18.

21. A vehicle-mounted power supply, characterized in that: The constituent circuit of the vehicle-mounted power supply includes the bidirectional conversion circuit according to any one of claims 1 to 12.

22. A vehicle, characterized in that: It includes the bidirectional conversion circuit as described in any one of claims 1 to 12, or includes the vehicle-mounted power supply as described in claim 21, or includes the controller as described in claim 19, or includes the computer-readable storage medium as described in claim 20.

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