Primary side feedback bidirectional flyback voltage conversion circuit based on auxiliary coil commutation circuit

Abstract

The utility model discloses a primary side feedback bidirectional flyback voltage conversion circuit based on an auxiliary coil commutation circuit. The primary side feedback bidirectional flyback voltage conversion circuit comprises a flyback transformer, an auxiliary coil commutation unit, a control unit and a main power loop. The auxiliary coil reversing unit is connected with the control unit; the control unit is connected with the main power loop, and the main power loop is connected with the flyback transformer; wherein the auxiliary coil commutation unit is used for enabling a coil of the flyback transformer to be subjected to commutation when the circuit is in a reverse DCDC conversion mode. By implementing the circuit provided by the utility model, a more efficient and safer battery equalization solution can be provided for the battery pack, the cost is lower and the stability is higher than that of the traditional secondary side feedback scheme, the key problems in the current equalization technology can be solved, and the circuit can be widely applied to a battery management system and has a wide application prospect. And the service life and efficiency of the whole battery pack are improved.

Description

Technical Field

[0001] This utility model relates to the field of bidirectional power supply active balancing circuit technology, and in particular to a primary-side feedback bidirectional flyback voltage conversion circuit based on an auxiliary coil commutation circuit. Background Technology

[0002] As battery packs experience voltage imbalances during prolonged operation, battery balancing technology becomes crucial in battery management systems. Active balancing technology efficiently balances individual cell voltages through energy transfer, extending battery life and improving overall performance. Most existing active balancing circuits employ a secondary-side feedback design, which monitors the secondary battery status and feeds feedback to the primary side to regulate battery balance. While the secondary-side feedback scheme offers advantages such as well-defined control characteristics, it also faces challenges including high isolation withstand voltage requirements, a significant risk of isolation breakdown, and higher costs.

[0003] Compared to secondary-side feedback, primary-side feedback simplifies isolation issues and reduces system complexity and cost because it directly monitors voltage and current in the main circuit. However, primary-side feedback also faces challenges, particularly the potential for conflicting positive and negative voltages in bidirectional DC-DC converters, requiring sophisticated control logic to ensure stable circuit operation. The design requirements for primary-side feedback schemes are high, especially when rapidly adjusting current and voltage, necessitating high precision to avoid battery damage.

[0004] Overall, while the secondary side feedback scheme has advantages in control, it is more costly and complex; while the primary side feedback scheme reduces isolation problems and costs, but requires higher design accuracy.

[0005] Therefore, it is necessary to design a new method to provide a more efficient and safer battery balancing solution for battery packs, with lower cost and higher stability than traditional secondary-side feedback schemes. This method can not only solve the key problems in current balancing technology, but also be widely used in battery management systems to improve the lifespan and efficiency of the entire battery pack. Utility Model Content

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a primary-side feedback bidirectional flyback voltage conversion circuit based on an auxiliary coil commutation circuit.

[0007] To solve the above-mentioned technical problems, the purpose of this utility model is achieved through the following technical solution: providing a primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit, including: a flyback transformer, an auxiliary coil commutation unit, a control unit, and a main power circuit; the auxiliary coil commutation unit is connected to the control unit; the control unit is connected to the main power circuit, and the main power circuit is connected to the flyback transformer; wherein, the auxiliary coil commutation unit is used to enable the coil of the flyback transformer to commutate when the circuit is in reverse DC-DC conversion mode.

[0008] The further technical solution is as follows: the auxiliary coil commutation unit includes a first commutation unit and a second commutation unit; the control unit includes a first control unit and a second control unit; the main power circuit includes a first main power circuit and a second main power circuit; wherein the flyback transformer includes a primary winding and a secondary winding; the first commutation unit is connected to the primary winding, the first commutation unit is connected to the first control unit, and the first control unit is connected to the first main power circuit; the second commutation unit is connected to the secondary winding, the second commutation unit is connected to the second control unit, and the second control unit is connected to the second main power circuit.

[0009] The further technical solution is as follows: the first commutation unit includes a commutation relay S1.

[0010] The further technical solution is as follows: the second commutation unit includes a commutation relay S2.

[0011] The further technical solution is as follows: the first control unit includes a PWM control chip U23.

[0012] The further technical solution is as follows: the second control unit includes a PWM control chip U18.

[0013] The further technical solution is as follows: the first main power circuit includes a switch Q7; the PWM control chip U23 is also connected to the flyback transformer via a switch Q7.

[0014] The further technical solution is as follows: the second main power circuit includes a switch Q2; the PWM control chip U18 is also connected to the flyback transformer via a switch Q2.

[0015] The further technical solution is as follows: the flyback transformer is connected to the commutation relay S2 through transistor Q4.

[0016] The further technical solution is as follows: the flyback transformer is connected to the commutation relay S1 through transistor Q1.

[0017] The advantages of this invention compared to existing technologies are as follows: This invention achieves voltage conversion through a flyback transformer, an auxiliary coil commutation unit, a control unit, and a main power circuit. The auxiliary coil commutation unit is responsible for commutating the auxiliary coil between forward and reverse DC-DC conversion modes to meet the charging and discharging requirements of the battery pack. Compared to traditional secondary-side feedback schemes, this design reduces circuit complexity and cost while improving stability and response speed. This circuit scheme can be widely used in battery management systems to improve the balancing efficiency of the battery pack, extend its service life, and ensure efficient and safe operation of the battery pack under different operating conditions.

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic block diagram of a primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit provided for an embodiment of this utility model;

[0021] Figure 2 A detailed circuit diagram of the primary-side feedback bidirectional flyback voltage converter circuit based on the auxiliary coil commutation circuit provided in this embodiment of the present invention;

[0022] Explanation of the markings in the image:

[0023] 10. Flyback transformer; 20. First commutation unit; 21. Second commutation unit; 30. First control unit; 31. Second control unit; 40. First main power circuit; 41. Second main power circuit. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0025] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0028] Battery balancing technology is crucial in battery management systems. Active balancing balances battery voltage through energy transfer, extending battery life and improving efficiency. Secondary-side feedback design is commonly used in active balancing circuits, adjusting battery balance by monitoring the secondary battery state, exhibiting well-defined control characteristics. Advantages of secondary-side feedback include good control performance, but it faces challenges such as high isolation withstand voltage requirements, a high risk of isolation breakdown, and high cost. In contrast, primary-side feedback simplifies isolation issues, reduces system complexity and cost, and directly monitors voltage and current in the main circuit. Primary-side feedback schemes pose a risk of positive and negative voltage conflicts in bidirectional DC-DC converters, requiring precise control logic to ensure circuit stability. Although primary-side feedback reduces cost, it demands higher design precision, especially when rapidly adjusting current and voltage. Overall, secondary-side feedback offers better controllability but is more costly and complex, while primary-side feedback excels in cost reduction and design simplification but requires higher precision.

[0029] Therefore, this utility model provides a primary-side feedback bidirectional flyback voltage conversion circuit based on an auxiliary coil commutation circuit, which provides a more efficient and safer battery balancing solution for battery packs. It has lower cost and higher stability than traditional secondary-side feedback schemes. It can not only solve the key problems in current balancing technology, but also be widely used in battery management systems to improve the service life and efficiency of the entire battery pack.

[0030] Specifically, this primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit achieves high-efficiency energy conversion of the battery pack by precisely switching between forward and reverse DC-DC conversion modes. It combines an auxiliary coil commutation unit with a PWM control unit to optimize energy transfer, reduce losses, and improve overall conversion efficiency. Compared to traditional secondary-side feedback schemes, this scheme uses primary-side feedback technology, which not only reduces system costs but also improves circuit stability and anti-interference capabilities. Through bidirectional control and main power loop design, it ensures precise battery balancing during charging and discharging, reducing overcharging or over-discharging of individual cells and ensuring battery safety. This technology can be widely applied in battery management systems, effectively improving battery pack lifespan and overall efficiency.

[0031] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0032] Please see Figure 1 A primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit includes: a flyback transformer 10, an auxiliary coil commutation unit, a control unit, and a main power circuit; the auxiliary coil commutation unit is connected to the control unit; the control unit is connected to the main power circuit, and the main power circuit is connected to the flyback transformer 10; wherein, the auxiliary coil commutation unit is used to enable the coil of the flyback transformer 10 to commutate when the circuit is in reverse DC-DC conversion mode.

[0033] In this embodiment, the flyback transformer 10 is the core component of the circuit, responsible for the transmission and isolation of electrical energy.

[0034] The flyback transformer 10 performs voltage conversion through magnetic energy conversion between the primary side (input side) and the secondary side (output side). It can support bidirectional voltage conversion from high to low or low to high, depending on the operating mode (forward DC-DC conversion or reverse DC-DC conversion). During forward conversion, it converts the input voltage to the output voltage, and during reverse conversion, it does the opposite, regulating the output voltage and feeding it back to the input.

[0035] The auxiliary coil commutation unit includes commutation relays (such as S1 and S2) for controlling the commutation of auxiliary coils N1 and N4.

[0036] The auxiliary coil commutation unit's function is to switch the switch according to different circuit operating modes, controlling the forward and reverse DC-DC conversion. Specifically, it determines whether the relay is enabled, thus affecting the power supply and feedback path of the auxiliary coil and control unit. N2 and N3 are coils belonging to the main power circuit.

[0037] Forward operating mode: commutator relays S1 and S2 are disabled, auxiliary coils N1 and N4 do not commutate, and the VCC power supply of PWM chip U23 is enabled. At this time, the circuit performs forward voltage conversion.

[0038] Reverse working mode: When commutation relays S1 and S2 are enabled, they control the commutation of auxiliary coils N1 and N4, and start the PWM control chip U18 to supply power for reverse voltage conversion.

[0039] The control unit typically includes a PWM control chip (such as U23 and U18) and other regulation circuits, which are responsible for regulating voltage and current to ensure stable circuit operation.

[0040] PWM Control Chip U23: This is a PWM control chip responsible for generating pulse width modulation (PWM) signals to adjust the on-time and off-time of switching transistors (such as MOSFETs), thereby controlling the current flow and voltage output. In forward DC-DC conversion, U23 is powered on, controlling the primary-side current and regulating the secondary-side voltage.

[0041] PWM Control Chip U18: This is another PWM control chip. When the circuit switches to reverse DC-DC conversion mode, the U18 is powered on, controlling the secondary current and adjusting the primary voltage. In this mode, the secondary voltage controls the primary voltage and current through feedback, ensuring bidirectional power transfer.

[0042] The main power circuit consists of the primary and secondary main power supply sections, and is responsible for the energy transmission of voltage conversion.

[0043] The main power circuit includes the primary and secondary sides of the flyback transformer 10, as well as switching elements (such as MOSFETs). In forward mode, the main power circuit is responsible for converting the input electrical energy into secondary electrical energy through the primary side and providing a stable output voltage; in reverse mode, the main power circuit controls the voltage and current of the primary side through feedback from the secondary side, thereby realizing the reverse transmission of electrical energy.

[0044] In one embodiment, please refer to Figure 1 The aforementioned auxiliary coil commutation unit includes a first commutation unit 20 and a second commutation unit 21; the control unit includes a first control unit 30 and a second control unit 31; the main power circuit includes a first main power circuit 40 and a second main power circuit 41; wherein, the flyback transformer 10 includes a primary winding and a secondary winding; the first commutation unit 20 is connected to the primary winding, the first commutation unit 20 is connected to the first control unit 30, and the first control unit 30 is connected to the first main power circuit 40; the second commutation unit 21 is connected to the secondary winding, the second commutation unit 21 is connected to the second control unit 31, and the second control unit 31 is connected to the second main power circuit 41.

[0045] In this embodiment, the auxiliary coil commutation unit is responsible for commutating the auxiliary coil according to different operating modes (forward and reverse). This part consists of two components:

[0046] The primary coil includes coils N1 and N2, and the secondary coil includes coils N3 and N4.

[0047] First commutation unit 20: connected to N2 in the primary winding of flyback transformer 10;

[0048] Second commutation unit 21: connected to the secondary coil N4 of flyback transformer 10.

[0049] These two commutation units are switched by relays, ensuring that the circuit can flexibly commutate the auxiliary coil in different operating modes, not only meeting the forward energy transmission requirements, but also enabling energy feedback in reverse mode.

[0050] The control unit is the core of the circuit; it is responsible for adjusting the voltage and current on the primary and secondary sides based on signal feedback. The control unit includes:

[0051] First control unit 30: Used to control circuit operation in forward mode. By receiving feedback signals from the first commutation unit 20 (e.g., primary-side current feedback signal), the first control unit 30 adjusts the magnitude of the primary-side current to ensure that the primary-side current is within a specified range, avoiding overcurrent or undercurrent. The first control unit 30 is also responsible for adjusting the current and voltage in the main power circuit according to the feedback information to ensure stable output.

[0052] Second control unit 31: Used to control the circuit operation in reverse mode. In this mode, the secondary side adjusts the current and voltage of the primary side through feedback voltage and current (such as the signal from the secondary side current sensor). Second control unit 31 receives the voltage and current signals fed back from the secondary side, and then adjusts the operating state of the primary side to ensure stable energy transmission and feedback.

[0053] These two control units adjust the current and voltage of the primary and secondary sides in the forward and reverse modes respectively through their respective feedback signals to ensure that the circuit can maintain stable output and energy feedback in different operating modes.

[0054] The main power circuit is responsible for the actual conversion and transmission of electrical energy. It is divided into:

[0055] The first main power circuit 40 is connected to the first control unit 30 and is responsible for converting input electrical energy into output electrical energy in forward mode. This circuit controls the current flow by adjusting the operating state of the primary side (such as adjusting the MOSFET switch) to ensure that the primary side current provides an appropriate voltage output according to the load demand.

[0056] The second main power circuit 41 is connected to the second control unit 31 and is responsible for regulating the primary current in reverse mode. The feedback signal of the secondary voltage controls the voltage and current in this circuit to ensure that electrical energy returns from the secondary side to the source, realizing energy feedback and recovery.

[0057] The flyback transformer 10 is responsible for the conversion and transmission of electrical energy in this circuit, and mainly consists of two parts:

[0058] Primary coil: Connected to the first commutation unit 20, it is mainly used to control the forward current flow of the circuit. By regulating the current and voltage of the primary coil, the circuit can provide a stable output voltage to the load.

[0059] Secondary coil: Connected to the second commutation unit 21, mainly used for reverse energy transmission. In reverse mode, the secondary coil adjusts the operating state of the primary coil through a feedback signal to achieve energy feedback.

[0060] During operation, the circuit adjusts the flow of energy by switching between different modes:

[0061] Forward mode: When commutation relays S1 and S2 are disabled, PWM control chip U23 is activated, and the first control unit 30 adjusts the current and voltage on the primary side to ensure that the load receives a stable voltage output.

[0062] Reverse mode: When the circuit switches to the reverse working mode, when the commutation relays S1 and S2 are enabled, the first commutation unit 20 and the second commutation unit 21 enable the secondary coil commutation, and the second control unit 31 adjusts the primary voltage and current according to the feedback signal to ensure that the electrical energy is transmitted in reverse to the source.

[0063] This design enables bidirectional voltage conversion, providing a stable voltage to the load in forward mode and feeding energy back to the source in reverse mode. The precise feedback mechanism and collaboration between the modules and the commutation unit ensure the stability and efficiency of power transmission.

[0064] In one embodiment, please refer to Figure 2 The first commutation unit 20 described above includes a commutation relay S1. In one embodiment, please refer to... Figure 2 The aforementioned second commutation unit 21 includes a commutation relay S2.

[0065] In one embodiment, please refer to Figure 2 The first control unit 30 mentioned above includes a PWM control chip U23.

[0066] In one embodiment, please refer to Figure 2 The aforementioned second control unit 31 includes a PWM control chip U18.

[0067] In one embodiment, please refer to Figure 2 The first main power circuit 40 mentioned above includes a switch Q7; the PWM control chip U23 is also connected to the flyback transformer 10 via a switch Q7.

[0068] In one embodiment, please refer to Figure 2 The aforementioned second main power circuit 41 includes a switch Q2; the PWM control chip U18 is also connected to the flyback transformer 10 via a switch Q2.

[0069] In one embodiment, please refer to Figure 2 The aforementioned flyback transformer 10 is connected to the commutation relay S2 via transistor Q4.

[0070] In one embodiment, please refer to Figure 2 The aforementioned flyback transformer 10 is connected to the commutation relay S1 via transistor Q1.

[0071] Specifically, in this embodiment, the first commutation unit 20 is composed of a commutation relay S1. Its function is to control the operating mode of the circuit and determine the direction of current flow.

[0072] In forward DC-DC conversion mode, S1 is disabled, meaning the relay is in the "off" state. At this time, the PWM control chip U23 is powered by VCC, enabling it to control the current regulation on the primary side. The state of the commutation relay S1 determines the current flow path in forward operation mode.

[0073] In reverse DC-DC conversion mode, S1 is enabled, meaning the relay is in the "closed" state. At this time, the current flow path is switched, the auxiliary coil is reversed, and the feedback current of the auxiliary coil enters the primary side of the flyback transformer 10 through S1, thereby adjusting the reverse current transmission.

[0074] The second commutation unit 21 consists of a commutation relay S2, which functions similarly to S1, but is mainly used for switching the current path in reverse operating mode.

[0075] In reverse DC-DC conversion mode, S2 is enabled, meaning the relay is in the "closed" state. At this time, current flows through S2 to the secondary coil, completing the energy feedback process.

[0076] In forward DC-DC conversion mode, S2 is disabled, meaning the relay is in the "open" state, which allows current to flow to the primary side and prevents the secondary side from participating in load current transmission.

[0077] The first control unit 30 consists of a PWM control chip U23, which is responsible for controlling the primary current in forward mode. U23 regulates the current flow through the primary side of the flyback transformer 10 by controlling the state of the switch Q7.

[0078] In forward DC-DC conversion mode, the PWM chip U23 is enabled by the VCC power supply and outputs a PWM signal to adjust the switching frequency and duty cycle of the switch Q7, thereby controlling the secondary voltage and maximum current according to the feedback voltage and CS_P current to ensure the stability of power conversion.

[0079] The function of U23 is to precisely adjust the operating state of the primary side, so that the flyback transformer 10 can provide the correct voltage and current output and maintain system stability.

[0080] The second control unit 31 consists of a PWM control chip U18, which mainly operates in reverse mode to control the secondary current and the feedback mechanism. U18 manages the regulation of the secondary current by controlling the switching device Q2.

[0081] In reverse DC-DC conversion mode, the PWM chip U18, enabled by its power supply VCC, outputs a PWM signal to regulate the switching state of Q2, thereby controlling the voltage and current on the secondary side and ensuring energy feedback to the primary side. By regulating the current on the secondary side, U18 ensures current stability and maximum power transfer in reverse mode.

[0082] U18 adjusts the primary voltage and maximum current based on the feedback voltage and CS_S current to achieve stable reverse power transfer.

[0083] The first main power circuit 40 includes a switch Q7, which regulates the current flow according to the output of the PWM control chip U23. Q7 is connected between the primary side and the PWM control chip U23, controlling the current transmission in the forward operating mode.

[0084] In the forward DC-DC conversion mode, the switch Q7 is controlled by the PWM chip U23, which adjusts the on-time and frequency of the switch according to its PWM signal, thereby regulating the current flowing through the primary side of the flyback transformer 10.

[0085] The switching state of Q7 directly affects the current flow on the primary side of the flyback transformer 10, and thus determines the energy transfer efficiency.

[0086] The second main power circuit 41 includes a switch Q2, which adjusts the secondary current according to the output of the PWM control chip U18, thereby affecting the current feedback in reverse mode. Q2 is connected between the secondary side and the PWM control chip U18.

[0087] In reverse DC-DC conversion mode, the switching element Q2 controls the feedback of the secondary current through the regulation of the PWM control chip U18. U18 ensures the correct current and voltage on the secondary side by adjusting the conduction state of Q2, thereby completing the energy feedback process.

[0088] Q2 controls the timing and magnitude of the secondary-side current flow, affecting the current and voltage fed back to the primary side, thus ensuring efficient energy transfer.

[0089] The flyback transformer 10 is connected to the commutation relay S2 via transistor Q4, and its function is to manage the current feedback on the secondary side in reverse mode.

[0090] In reverse DC-DC conversion mode, transistors Q4 and S2 work together to control the flow of current on the secondary side, transferring the feedback current from the secondary side to the primary side. This connection enables the flyback transformer 10 to achieve current feedback and optimize energy transfer.

[0091] The on / off state of Q4 is adjusted by the PWM control chip U18, which affects the magnitude of the secondary current and the feedback timing.

[0092] The flyback transformer 10 is connected to the commutation relay S1 via transistor Q1, and its function is to control the flow of primary current in forward mode.

[0093] In forward DC-DC conversion mode, transistor Q1 controls the primary current flow via S1. At this time, the switching state of Q1 is adjusted by the PWM control chip U23 to ensure that the primary current meets the load requirements.

[0094] The switching on and off of Q1 is controlled by U23, which adjusts the timing of the current flowing through the primary coil of the flyback transformer 10, thereby affecting the efficiency of reverse and forward conversion.

[0095] This embodiment, through the precise coordination of the control unit, commutation relays, and switches, enables the circuit to operate flexibly in both forward and reverse DC-DC conversion modes. In forward mode, the PWM control chip U23 regulates the primary current by controlling switch Q7, while S1 is disabled. In reverse mode, the PWM control chip U18 regulates the secondary current by controlling switch Q2, while S1 and S2 are enabled, thus achieving energy feedback. The coordination between commutation relays S1 and S2 and transistors Q1 and Q4 ensures the switching of the current flow path, guaranteeing the stability of the voltage conversion.

[0096] In one embodiment, please refer to Figure 2 The aforementioned commutation relay S1 is also connected to a Zener diode D1, a resistor R1, a resistor R2, and a capacitor C1. The aforementioned resistor R1 is connected to the Zener diode D1, and the Zener diode D1 is connected to the commutation relay S1. The resistor R2 is connected to the capacitor C1, and the capacitor C1 is connected to the commutation relay S1. The base of the aforementioned transistor Q1 is connected to R3. A resistor R4 is connected between the resistor R3 and the transistor Q1. The resistor R4 is connected to the emitter of the transistor Q1. The collector of the transistor Q1 is connected to the commutation relay S1.

[0097] In one embodiment, please refer to Figure 2 The aforementioned commutation relay S1 is also connected to a Zener diode D5, resistors R7 and R9, and capacitor C27. Resistor R7 is connected to Zener diode D5, Zener diode D5 is connected to commutation relay S2, resistor R9 is connected to capacitor C27, and capacitor C27 is connected to commutation relay S2. The base of the aforementioned transistor Q4 is connected to resistor R6, resistor R6 is connected to transistor Q4, and resistor R18 is connected to the emitter of transistor Q4. The collector of transistor Q4 is connected to commutation relay S2.

[0098] Please see Figure 2 The flyback transformer 10 mentioned above is transformer T2 in the figure.

[0099] The circuit in this embodiment uses primary-side feedback technology, meaning the feedback signal comes directly from the primary winding of the flyback transformer 10, rather than the secondary winding. This reduces the requirement for high-voltage isolation, thereby lowering the complexity and cost of the design.

[0100] The application of primary-side feedback in bidirectional flyback voltage converter circuits can ensure the real-time performance of the feedback signal, avoiding the delay and complexity that may be caused by traditional isolated feedback circuits.

[0101] This circuit switches its operating mode via an auxiliary coil commutation unit, controlling the switching between forward DC-DC conversion and reverse DC-DC conversion modes. The commutation unit uses relays (such as S1 and S2) and transistors (such as Q1 and Q4) to perform the switching operation.

[0102] The introduction of the auxiliary coil commutation circuit enables the circuit to switch freely between different voltage modes and simplifies the design of the control strategy, avoiding complex control algorithms.

[0103] The output voltage is adjusted by using PWM control chips (such as U23 and U18) as control units to control the switching transistors (MOSFETs, such as Q7 and Q2) to turn on and off through pulse width modulation (PWM).

[0104] Since control chips are typically standardized integrated circuits, using these basic components can reduce circuit complexity and facilitate efficient voltage regulation and control, ensuring system stability and reliability.

[0105] By using a simple voltage and current sampling mechanism, an auxiliary coil commutation circuit, and a PWM module, precise control of voltage and current is achieved, simplifying the design of the feedback path and reducing costs. The feedback signal can be acquired using low-cost components such as current sampling resistors and voltage divider resistors.

[0106] The circuit design emphasizes high reliability and stability. The selected components, such as MOSFETs and transistors, are basic components that are readily available and have high reliability and durability.

[0107] The circuit enables bidirectional DC-DC conversion, allowing free switching between forward and reverse voltage conversion. This is crucial for applications requiring switching between different voltage levels (such as energy storage systems or electric vehicle charging). The bidirectional functionality relies primarily on the coordinated operation of the flyback transformer 10, the commutation relay, the control unit, and the main power circuit.

[0108] The circuit's high stability stems from the high efficiency of the feedback loop. The primary-side feedback can quickly respond to load changes, ensuring a consistently stable output voltage. High reliability is guaranteed by using basic and mature components (such as PWM control chips, MOSFETs, relays, and transistors), reducing reliance on complex and specialized components and lowering potential failure risks.

[0109] Because the components used are standardized and the design is simple, the entire circuit system can maintain a small size and adapt to space-constrained applications (such as portable power supplies, embedded systems, etc.).

[0110] This bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit successfully achieves a small-size, highly stable, and highly reliable bidirectional DC-DC conversion solution through a simplified primary-side feedback mechanism, simple voltage and current sampling, PWM control module, basic components (such as MOSFETs, relays, and transistors), and commutation circuit design. Simultaneously, the primary-side feedback reduces the isolation withstand voltage requirement, and the auxiliary coil commutation circuit makes the circuit design simpler and more cost-effective.

[0111] The aforementioned bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit achieves voltage conversion through a flyback transformer 10, an auxiliary coil commutation unit, a control unit, and a main power circuit. The auxiliary coil commutation unit is responsible for commutating the auxiliary coil between forward and reverse DC-DC conversion modes to meet the charging and discharging requirements of the battery pack. Compared to traditional secondary-side feedback schemes, this design reduces circuit complexity and cost while improving stability and response speed. This circuit scheme can be widely used in battery management systems to improve the balancing efficiency of the battery pack, extend its service life, and ensure the efficient and safe operation of the battery pack under different operating conditions.

[0112] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit, characterized in that, include: The circuit includes a flyback transformer, an auxiliary coil commutation unit, a control unit, and a main power circuit; the auxiliary coil commutation unit is connected to the control unit; the control unit is connected to the main power circuit, and the main power circuit is connected to the flyback transformer; wherein, the auxiliary coil commutation unit is used to enable the flyback transformer coil to commutate when the circuit is in reverse DC-DC conversion mode.

2. The primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit according to claim 1, characterized in that, The auxiliary coil commutation unit includes a first commutation unit and a second commutation unit; the control unit includes a first control unit and a second control unit; the main power circuit includes a first main power circuit and a second main power circuit; wherein the flyback transformer includes a primary winding and a secondary winding; the first commutation unit is connected to the primary winding, the first commutation unit is connected to the first control unit, and the first control unit is connected to the first main power circuit; the second commutation unit is connected to the secondary winding, the second commutation unit is connected to the second control unit, and the second control unit is connected to the second main power circuit.

3. The primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit according to claim 2, characterized in that, The first commutation unit includes a commutation relay S1.

4. The primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit according to claim 2, characterized in that, The second commutation unit includes a commutation relay S2.

5. The primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit according to claim 2, characterized in that, The first control unit includes a PWM control chip U23.

6. The primary-side feedback bidirectional flyback voltage converter circuit based on the auxiliary coil commutation circuit according to claim 2, characterized in that, The second control unit includes a PWM control chip U18.

7. The primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit according to claim 5, characterized in that, The first main power circuit includes a switch Q7; the PWM control chip U23 is also connected to the flyback transformer via a switch Q7.

8. The primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit according to claim 6, characterized in that, The second main power circuit includes a switch Q2; the PWM control chip U18 is also connected to the flyback transformer via a switch Q2.

9. The primary-side feedback bidirectional flyback voltage converter circuit based on the auxiliary coil commutation circuit according to claim 4, characterized in that, The flyback transformer is connected to the commutation relay S2 via transistor Q4.

10. The primary-side feedback bidirectional flyback voltage converter circuit based on an auxiliary coil commutation circuit according to claim 3, characterized in that, The flyback transformer is connected to the commutation relay S1 via transistor Q1.

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