Flyback high-voltage BUCK power supply circuit system

Abstract

The invention relates to the technical field of power electronics, in particular to a flyback high-voltage BUCK power circuit system which comprises a flyback transformer. The primary side of the flyback transformer comprises two primary windings and an auxiliary winding, and the secondary side of the flyback transformer comprises three secondary windings; the two primary windings are connected in series to form a series primary winding; a series primary winding of the flyback transformer is connected with the high-voltage power supply input circuit and the step-down and control circuit; an auxiliary winding of the flyback transformer is connected with an auxiliary input circuit; and three secondary windings of the flyback transformer are respectively connected with a U-phase voltage output circuit, a W-phase voltage output circuit and a V-phase voltage output circuit. According to the invention, the reliability and stability of the flyback high-voltage BUCK power supply circuit system in new energy motor control can be improved.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, specifically to a flyback high-voltage BUCK power supply circuit system. Background Technology

[0002] The flyback high-voltage BUCK power supply circuit is an isolated switching power supply topology characterized by its simple structure, low cost, and electrical isolation, making it widely used in high-voltage input scenarios. This circuit achieves voltage conversion through the magnetic energy storage and release of a transformer. It typically uses a high-voltage AC input as the input source, and after being controlled by a switching transistor, outputs a stable low-voltage DC power supply, providing isolated power to various electronic devices. Its core advantage lies in eliminating the need for complex synchronous rectification circuits and effectively isolating the high-voltage and low-voltage sides, thus occupying an important position in industrial control, communication equipment, and consumer electronics.

[0003] In new energy motor control systems, flyback high-voltage BUCK power supply circuits play a crucial role. For example, in electric vehicle motor drives, this power supply provides isolated low-voltage power to control chips, sensors, and communication modules, ensuring safe isolation between the high-voltage power system and the low-voltage control circuit, and preventing control failures caused by electrical interference. However, while flyback designs can initially meet basic requirements, they have revealed a series of key defects in actual deployments, severely restricting the overall performance and lifespan of new energy systems.

[0004] The applicant discovered the following main problems with flyback high-voltage BUCK power supply circuits in the application scenarios of new energy motor control during actual research: 1) The high-frequency switching action of the flyback converter generates a large amount of electromagnetic noise, which can easily couple to the motor control signal line through radiation or conduction paths. In new energy motor systems, the control signal is sensitive to noise, which can easily lead to control distortion, false triggering, or even system shutdown. To suppress noise, existing technologies require the addition of an EMI filter, but such additional components not only occupy space but also introduce additional losses, further reducing the overall system efficiency, and are difficult to optimize and integrate in a compact motor controller. 2) The load of new energy motors often fluctuates drastically, and existing flyback circuits exhibit large output voltage ripple and significant response hysteresis under wide input voltage ranges or sudden load changes, leading to frequent adjustments in the control loop, affecting the motor speed regulation accuracy and dynamic performance, and even causing system oscillation. Existing technologies rely on simple feedback mechanisms, which cannot effectively compensate for input / load changes and are difficult to meet the real-time and reliability requirements of new energy equipment.

[0005] In summary, existing flyback high-voltage BUCK power supply circuits have shortcomings in noise suppression and voltage fluctuation control, making it difficult to meet the reliability and stability requirements of new energy motor control. Therefore, there is an urgent need for a flyback high-voltage BUCK power supply circuit system that can help improve the reliability and stability of new energy motor control. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the technical problem to be solved by this invention is: how to provide a flyback high-voltage BUCK power supply circuit system that effectively filters out high-frequency noise and interference in the input voltage through multi-stage filtering design of the high-voltage power input circuit, achieves stable regulation of the input voltage through feedback control of the step-down and control circuits, and effectively suppresses common-mode noise through the voltage output circuit, thereby improving the reliability and stability of the flyback high-voltage BUCK power supply circuit system in the control of new energy motors.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A flyback high-voltage BUCK power supply circuit system, including a flyback transformer;

[0009] The primary side of a flyback transformer includes two primary windings and one auxiliary winding, while the secondary side includes three secondary windings; two primary windings are connected in series to form a series primary winding.

[0010] The series primary winding of the flyback transformer is connected to the high-voltage power input circuit and the step-down and control circuit;

[0011] The auxiliary winding of the flyback transformer is connected to the auxiliary input circuit;

[0012] The three secondary windings of the flyback transformer are connected to the voltage output circuits of the U-phase, W-phase, and V-phase, respectively.

[0013] Preferably, the high-voltage power input circuit includes an ultra-fast recovery diode D2, a current-limiting resistor R2, a power inductor L1, and four decoupling capacitors;

[0014] The anode of the ultrafast recovery diode D2 is connected to the external bus voltage input port, and the cathode is connected to the first end of the current limiting resistor R2. The second end of the current limiting resistor R2 is connected to the input terminal of the power inductor L1. The output terminal of the power inductor L1 is connected in series with four decoupling capacitors C1, C9, C10, and C2. The bus voltage is filtered by the four decoupling capacitors C1, C9, C10, and C2 and then connected to the first end of the primary winding of the flyback transformer.

[0015] Preferably, the auxiliary input circuit includes a current-limiting resistor R7, a Zener diode ZD1, an ultrafast recovery diode D4, and an aluminum electrolytic capacitor C13;

[0016] The cathode of the ultrafast recovery diode D4 is connected to the current-limiting resistor R7, and the anode is connected to the first end of the auxiliary winding of the flyback transformer.

[0017] Zener diode ZD1 is connected in parallel with ultrafast recovery diode D4. The cathode of Zener diode ZD1 is connected to current limiting resistor R7, and the anode is connected to the second end of the auxiliary winding of flyback transformer.

[0018] An aluminum electrolytic capacitor C13 is connected in parallel with a Zener diode ZD1. The first terminal of the aluminum electrolytic capacitor C13 is connected to a current-limiting resistor R7, and the second terminal is connected to the second terminal of the auxiliary winding of the flyback transformer.

[0019] Preferably, the step-down and control circuit includes a power control chip and its peripheral circuitry;

[0020] The drain of the power control chip is connected to the second end of the primary winding of the flyback transformer connected in series.

[0021] The input voltage terminal of the power control chip is connected to the output terminal of the power inductor L1 of the high-voltage power input circuit through six series voltage divider resistors R13, R17, R22, R27, R29, and R31; the anode of the Zener diode ZD3 is connected to the voltage divider resistor R29 through the series resistor R33, and the cathode is connected to the voltage divider resistor R31.

[0022] A first peripheral circuit, including a parallel Zener diode ZD2 and a parallel capacitor C26, is connected between the FWD pin and the SR pin of the power control chip. The cathode of the Zener diode ZD2 is connected to the FWD pin, and the anode is connected to the SR pin. The first end of the parallel capacitor C26 is connected to the FWD pin, and the second end is connected to the SR pin.

[0023] The BPP pin of the power control chip is connected to the current-limiting resistor R7 of the auxiliary input circuit;

[0024] A second peripheral circuit, consisting of a fast recovery diode D6, a fast recovery diode D5, and a voltage divider resistor R28 connected in series, is connected between the BPS and FB pins of the power control chip. The cathode of the fast recovery diode D6 is connected to the BPS pin, and the anode is connected to the anode of the Zener diode D5. The cathode of the Zener diode D5 is connected in series with the voltage divider resistor R28 and then connected to the FB pin.

[0025] A third peripheral circuit, consisting of a capacitor C30 connected in series and a current-limiting resistor R30, is connected between the IS pin and the FB pin of the power control chip. The first end of the capacitor C30 is connected to the IS pin, and the second end is connected in series with the current-limiting resistor R30 and then connected to the FB pin.

[0026] Preferably, an RCD snubber circuit is also connected between the drain of the power control chip and the power inductor L1 of the high-voltage power input circuit.

[0027] Preferably, the output voltage of the power control chip is calculated using the following formula:

[0028] ;

[0029] In the formula: This indicates the output voltage of the power control chip; This indicates the voltage at the FB pin of the power control chip; This indicates the resistance value of the current-limiting resistor R30; This indicates the resistance value of the voltage divider resistor R28.

[0030] Preferably, the input voltage of the power control chip is calculated using the following formula:

[0031] ;

[0032] In the formula: This indicates the input voltage of the power control chip; This indicates the Zener voltage of the Zener diode ZD3; , , , , , These represent the resistance values ​​of the voltage divider resistors R13, R17, R22, R27, R29, and R31, respectively. This indicates the output of the power inductor L1.

[0033] Preferably, the voltage output circuit of phase U includes a fast recovery diode D7, an aluminum electrolytic capacitor C22, a common mode inductor L4, and three filter capacitors C23, C24, and C2;

[0034] The cathode of the fast recovery diode D7 is connected to the first terminal of the first secondary winding of the flyback transformer, and the anode is connected to the first winding of the common-mode inductor L4; the second winding of the common-mode inductor L4 is connected to the second terminal of the first secondary winding of the flyback transformer.

[0035] An aluminum electrolytic capacitor C22 is connected in parallel with a common-mode inductor L4. The first terminal of the aluminum electrolytic capacitor C22 is connected to the first terminal of the first secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the first secondary winding of the flyback transformer.

[0036] Three filter capacitors C23, C24, and C25 are connected in parallel with aluminum electrolytic capacitor C22 and common-mode inductor L4, respectively. The first terminal of the three filter capacitors C23, C24, and C25 is connected to the first terminal of the first secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the first secondary winding of the flyback transformer.

[0037] Preferably, the voltage output circuit of phase W includes a fast recovery diode D3, an aluminum electrolytic capacitor C14, a common mode inductor L3, and three filter capacitors C16, C17, and C18.

[0038] The anode of the fast recovery diode D3 is connected to the first terminal of the second secondary winding of the flyback transformer, and the cathode is connected to the first winding of the common mode inductor L3; the second winding of the common mode inductor L3 is connected to the second terminal of the second secondary winding of the flyback transformer.

[0039] An aluminum electrolytic capacitor C14 is connected in parallel with a common-mode inductor L3. The first end of the aluminum electrolytic capacitor C14 is connected to the first end of the second secondary winding of the flyback transformer, and the second end is connected to the second end of the second secondary winding of the flyback transformer.

[0040] Three filter capacitors C16, C17, and C18 are connected in parallel with aluminum electrolytic capacitor C14 and common-mode inductor L3, respectively. The first terminal of the three filter capacitors C16, C17, and C18 is connected to the first terminal of the second secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the second secondary winding of the flyback transformer.

[0041] Preferably, the voltage output circuit of phase V includes a fast recovery diode D1, an aluminum electrolytic capacitor C4, a common mode inductor L2, and three filter capacitors C6, C7, and C8;

[0042] The anode of the fast recovery diode D1 is connected to the first terminal of the third secondary winding of the flyback transformer, and the cathode is connected to the first winding of the common-mode inductor L2; the second winding of the common-mode inductor L2 is connected to the second terminal of the third secondary winding of the flyback transformer.

[0043] An aluminum electrolytic capacitor C4 is connected in parallel with a common-mode inductor L2. The first end of the aluminum electrolytic capacitor C4 is connected to the first end of the third secondary winding of the flyback transformer, and the second end is connected to the second end of the third secondary winding of the flyback transformer.

[0044] The three filter capacitors C6, C7, and C8 are connected in parallel with the aluminum electrolytic capacitor C4 and the common mode inductor L2, respectively. The first terminal of the three filter capacitors C6, C7, and C8 is connected to the first terminal of the third secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the second secondary winding of the flyback transformer.

[0045] Compared with the prior art, the flyback high-voltage BUCK power supply circuit system of this invention has the following advantages:

[0046] This invention utilizes a multi-stage filtering design in the high-voltage power supply input circuit to effectively filter out high-frequency noise and interference in the input voltage, reduce input ripple, and ensure input voltage stability. The combination of the ultra-fast recovery diode D2 and the current-limiting resistor R2 effectively suppresses voltage spikes, protecting the circuit from high-voltage surges. The series connection of the power inductor L1 and four decoupling capacitors further enhances the filtering effect, thereby improving the system's anti-interference capability. The design of the high-voltage power supply input circuit enables the power supply to operate stably in high-noise and high-voltage fluctuation environments, effectively preventing the impact of voltage fluctuations on the system. Simultaneously, the stable input voltage provides a reliable foundation for the entire power supply system, thereby improving the reliability and stability of the flyback high-voltage BUCK power supply circuit system in new energy motor control.

[0047] This invention achieves stable input voltage regulation through a buck converter and feedback control circuit. The input voltage can be flexibly adjusted by changing the resistance values ​​of the current-limiting resistor R30 and the voltage-dividing resistor R28. The feedback loop design allows the system to monitor and automatically adjust the input voltage in real time, maintaining voltage stability. The combination of the voltage-dividing resistor network and the Zener diode ZD3 ensures stable input voltage for the power control chip, thereby improving the system's anti-interference capability. The buck converter and control circuit design enables the power system to maintain stable output over a wide range of input voltages, thus improving the adaptability and reliability of the flyback high-voltage buck power supply system. Simultaneously, the precise control capability of the power control chip allows the system to maintain high efficiency and high precision even under high-voltage environments, effectively handling input voltage fluctuations.

[0048] This invention provides a stable and reliable auxiliary voltage to the power control chip through the combination of a Zener diode ZD1 and an aluminum electrolytic capacitor C13 in the auxiliary input circuit, effectively preventing voltage fluctuations from affecting the chip's operation. The parallel combination of resistors R10 and capacitors C12 and R11 further filters out noise in the auxiliary voltage; while the connection between the auxiliary winding and the VPP pin of the power control chip ensures voltage stability. The design of the auxiliary input circuit improves the system's anti-interference capability, extends the chip's lifespan, and enables the flyback high-voltage BUCK power supply system to maintain stable operation under various working conditions. Simultaneously, the auxiliary power supply design simplifies the system design, reduces overall complexity, and thus improves the integration and reliability of the flyback high-voltage BUCK power supply system.

[0049] This invention effectively suppresses common-mode noise through the common-mode inductors in the U-phase, W-phase, and V-phase voltage output circuits. Multi-stage filtering (aluminum electrolytic capacitors and three small capacitors) significantly reduces output ripple and noise, ensuring high stability and low noise in the output voltage. The resistors and capacitors connected in parallel with the aluminum electrolytic capacitors optimize the circuit's damping characteristics, preventing resonance and thus improving the stability of the flyback high-voltage BUCK power supply circuit system. The design of the voltage output circuit guarantees high stability and low noise in the three-phase output, while the consistency of the circuit structure ensures the balance of the three-phase output, further improving the overall performance and reliability of the flyback high-voltage BUCK power supply circuit system. Attached Figure Description

[0050] To make the objectives, technical solutions, and advantages of the invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0051] Figure 1 This is a logic block diagram of a flyback high-voltage BUCK power supply circuit system.

[0052] Figure 2 This is a circuit diagram of a flyback high-voltage BUCK power supply system ("G03" in the diagram is the drawing number, such as "T1G03" which refers to flyback transformer T1). Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but only to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0054] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not mean that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] The following detailed explanation illustrates the specific implementation methods:

[0056] Example:

[0057] This embodiment discloses a flyback high-voltage BUCK power supply circuit system.

[0058] like Figure 1 As shown, a flyback high-voltage BUCK power supply circuit system includes a flyback transformer (T1).

[0059] The primary side of the flyback transformer (T1) includes two primary windings and one auxiliary winding, while the secondary side includes three secondary windings; the two primary windings are connected in series to form a series primary winding.

[0060] The series primary winding of the flyback transformer is connected to the high-voltage power input circuit and the step-down and control circuit;

[0061] The auxiliary winding of the flyback transformer is connected to the auxiliary input circuit;

[0062] The three secondary windings of the flyback transformer are connected to the voltage output circuits of the U-phase, W-phase, and V-phase, respectively.

[0063] In this invention, the high-voltage power input circuit receives high-voltage power from the bus voltage. The step-down and control circuit reduces the high voltage through frequency conversion and duty cycle adjustment, converting it to the required voltage. An RDC circuit absorbs voltage spikes to prevent chip overvoltage damage. The voltage output circuit provides three stable outputs via a transformer, rectification, filtering, and anti-reverse diodes. A feedback circuit is added at the U-phase output to sample the voltage. This invention reduces external electronic components by employing a highly integrated power control chip with a built-in MOSFET, providing a high-efficiency control method to improve the conversion efficiency and stability of the BUCK circuit, meeting the circuit requirements of modern motor controllers for DC high-voltage to low-voltage conversion and multiple outputs.

[0064] To better illustrate the technical solution of the present invention, this embodiment will be described in more detail through the following parts.

[0065] I. High-voltage power input circuit

[0066] In the specific implementation process, combined with Figure 2 As shown, the high-voltage power input circuit includes an ultra-fast recovery diode (UFRD) D2, a current-limiting resistor R2, a power inductor L1, and four decoupling capacitors; among them, the power inductor L1 is a shielded power inductor. The decoupling capacitors C1, C2, C9, and C10 are high-voltage surface-mount ceramic capacitors.

[0067] The anode of the ultrafast recovery diode D2 is connected to the external bus voltage input port, and the cathode is connected to the first terminal of the current limiting resistor R2. The second terminal of the current limiting resistor R2 is connected to the input terminal of the power inductor L1. The output terminal of the power inductor L1 is connected in series with four decoupling capacitors C1, C9, C10, and C2. The bus voltage is filtered by the four decoupling capacitors C1, C9, C10, and C2 and then connected to the first terminal of the primary winding of the flyback transformer (the two ends of a winding are called the first terminal and the second terminal, respectively).

[0068] The output terminal of the power inductor L1 is also connected to the first terminal of the primary winding of the flyback transformer in series; decoupling capacitors C9 and C10 are also connected to GND_UL.

[0069] In this embodiment, the diode D2 used for filtering the high-voltage power supply input circuit is an ultra-fast recovery diode, and C1, C2, C9, and C10 are high-voltage resistant surface-mount capacitors and inductor L1 to form a filter circuit to eliminate noise from the bus voltage.

[0070] This invention utilizes a multi-stage filtering design in the high-voltage power supply input circuit to effectively filter out high-frequency noise and interference in the input voltage, reduce input ripple, and ensure input voltage stability. The combination of the ultra-fast recovery diode D2 and the current-limiting resistor R2 effectively suppresses voltage spikes, protecting the circuit from high-voltage surges. The series connection of the power inductor L1 and four decoupling capacitors further enhances the filtering effect, thereby improving the system's anti-interference capability. The design of the high-voltage power supply input circuit enables the power supply to operate stably in high-noise and high-voltage fluctuation environments, effectively preventing the impact of voltage fluctuations on the system. Simultaneously, the stable input voltage provides a reliable foundation for the entire power supply system, thereby improving the reliability and stability of the flyback high-voltage BUCK power supply circuit system in new energy motor control.

[0071] II. Auxiliary Input Circuit

[0072] In the specific implementation process, combined with Figure 2 As shown, the auxiliary input circuit includes a current-limiting resistor R7, a Zener diode ZD1, an ultra-fast recovery diode D4, and an aluminum electrolytic capacitor C13.

[0073] The cathode of the ultrafast recovery diode D4 is connected to the current-limiting resistor R7, and the anode is connected to the first end of the auxiliary winding of the flyback transformer.

[0074] Zener diode ZD1 is connected in parallel with ultrafast recovery diode D4. The cathode of Zener diode ZD1 is connected to current limiting resistor R7, and the anode is connected to the second end of the auxiliary winding of flyback transformer.

[0075] An aluminum electrolytic capacitor C13 is connected in parallel with a Zener diode ZD1. The first terminal of the aluminum electrolytic capacitor C13 is connected to a current-limiting resistor R7, and the second terminal is connected to the second terminal of the auxiliary winding of the flyback transformer.

[0076] The auxiliary input circuit also includes:

[0077] A resistor R10 is connected in parallel with the electrolytic capacitor C13. The first end of the resistor R10 is connected to the current-limiting resistor R7, and the second end is connected to the second end of the auxiliary winding of the flyback transformer.

[0078] A capacitor C12 and a resistor R11 are connected in parallel and in series with the ultrafast recovery diode D4. The first end of the capacitor C12 is connected to the current-limiting resistor R7, and the second end is connected to the first end of the resistor R11. The second end of the resistor R11 is connected to the first end of the auxiliary winding of the flyback transformer.

[0079] This invention provides a stable and reliable auxiliary voltage to the power control chip through the combination of a Zener diode ZD1 and an aluminum electrolytic capacitor C13 in the auxiliary input circuit, effectively preventing voltage fluctuations from affecting the chip's operation. The parallel combination of resistors R10 and capacitors C12 and R11 further filters out noise in the auxiliary voltage; while the connection between the auxiliary winding and the VPP pin of the power control chip ensures voltage stability. The design of the auxiliary input circuit improves the system's anti-interference capability, extends the chip's lifespan, and enables the flyback high-voltage BUCK power supply system to maintain stable operation under various working conditions. Simultaneously, the auxiliary power supply design simplifies the system design, reduces overall complexity, and thus improves the integration and reliability of the flyback high-voltage BUCK power supply system.

[0080] III. Step-down and Control Circuit

[0081] In the specific implementation process, combined with Figure 2 As shown, the step-down and control circuit includes a power control chip (U1) and its peripheral circuits;

[0082] The drain (D) of the power control chip is connected to the second end of the primary winding of the flyback transformer connected in series.

[0083] The source (S) of the power control chip is connected to GND_HV;

[0084] The input voltage terminal (V terminal) of the power control chip is connected to the output terminal (VIN_H) of the power inductor L1 of the high-voltage power input circuit through six series voltage divider resistors R13, R17, R22, R27, R29, and R31; the anode of the Zener diode ZD3 is connected to the voltage divider resistor R29 through the series resistor R33, and the cathode is connected to the voltage divider resistor R31.

[0085] A first peripheral circuit, including a parallel Zener diode ZD2 and a parallel capacitor C26, is connected between the FWD and SR pins of the power control chip. The cathode of the Zener diode ZD2 is connected to the FWD pin, and the anode is connected to the SR pin. The first terminal of the parallel capacitor C26 is connected to the FWD pin, and the second terminal is connected to the SR pin. The first peripheral circuit also includes a resistor R18 connected to the cathode of the Zener diode ZD2. The FWD pin is connected to PIN16 on the secondary side of the flyback transformer via the Zener diode ZD2 to form a feedback loop.

[0086] The VOUT pin of the power control chip is connected to GND_UL_1 through a series capacitor C5;

[0087] The BPP pin of the power control chip is connected to the current-limiting resistor R7 of the auxiliary input circuit;

[0088] A second peripheral circuit is connected between the BPS and FB pins of the power control chip, including a fast recovery diode (FRD) D6, a fast recovery diode D5, and a voltage divider resistor R28 connected in series. The cathode of the fast recovery diode D6 is connected to the BPS pin, and the anode is connected to the anode of the Zener diode D5. The cathode of the Zener diode D5 is connected in series with the voltage divider resistor R28 and then connected to the FB pin. The cathode of the Zener diode D5 is also connected to the VOUT pin of the power control chip to form an overvoltage detection circuit. The second peripheral circuit also includes a resistor R26 and a capacitor C28 connected in parallel and in series with the voltage divider resistor R28.

[0089] A third peripheral circuit, including a capacitor C30 and a current-limiting resistor R30 connected in series, is connected between the IS and FB pins of the power control chip. The first end of the capacitor C30 is connected to the IS pin, and the second end is connected to the FB pin after being connected in series with the current-limiting resistor R30. The end of the current-limiting resistor R30 connected to the FB pin is also connected to the voltage divider resistor R28, and the end connected to the capacitor C30 is also connected to GND_UL_1. The third peripheral circuit also includes a capacitor C29 connected in parallel with the current-limiting resistor R30.

[0090] In this invention, since the output voltage of the FB pin remains constant during normal operation of the power control chip, the output voltage of the power control chip can be changed by adjusting the resistance values ​​of the current-limiting resistor R30 and the voltage divider resistor R28, thereby achieving voltage reduction and control of the flyback circuit through the transformer. Simultaneously, the bus voltage, after being filtered by the fast recovery diode D2, the current-limiting resistor R2, and the power inductor L1, is regulated by the voltage divider resistors R13, R17, R22, R27, R29, and R31, as well as the Zener diode ZD3, before supplying power to the power control chip. Furthermore, the auxiliary winding terminal (PIN8) of the flyback transformer (T1) is connected to the VPP terminal of the power control chip, ensuring the stability of the chip voltage.

[0091] Specifically, an RCD snubber circuit is connected between the drain (D) of the power control chip and the power inductor L1 of the high-voltage power input circuit. The RCD snubber circuit absorbs the peak voltage generated by the bus voltage to protect the power chip U1.

[0092] Specifically, the output voltage of the power control chip is calculated using the following formula:

[0093] ;

[0094] In the formula: This indicates the output voltage of the power control chip; This indicates the voltage at the FB pin (feedback pin) of the power control chip; This indicates the resistance value of the current-limiting resistor R30; This indicates the resistance value of the voltage divider resistor R28.

[0095] Specifically, the input voltage of the power control chip is calculated using the following formula:

[0096] ;

[0097] In the formula: This indicates the input voltage of the power control chip; This indicates the Zener voltage of the Zener diode ZD3; , , , , , These represent the resistance values ​​of the voltage divider resistors R13, R17, R22, R27, R29, and R31, respectively. This indicates the output of the power inductor L1.

[0098] This invention achieves stable input voltage regulation through a buck converter and feedback control circuit. The input voltage can be flexibly adjusted by changing the resistance values ​​of the current-limiting resistor R30 and the voltage-dividing resistor R28. The feedback loop design allows the system to monitor and automatically adjust the input voltage in real time, maintaining voltage stability. The combination of the voltage-dividing resistor network and the Zener diode ZD3 ensures stable input voltage for the power control chip, thereby improving the system's anti-interference capability. The buck converter and control circuit design enables the power system to maintain stable output over a wide range of input voltages, thus improving the adaptability and reliability of the flyback high-voltage buck power supply system. Simultaneously, the precise control capability of the power control chip allows the system to maintain high efficiency and high precision even under high-voltage environments, effectively handling input voltage fluctuations.

[0099] IV. Voltage Output Circuit of Phase U

[0100] In the specific implementation process, combined with Figure 2 As shown, the voltage output circuit of phase U includes a fast recovery diode D7, an aluminum electrolytic capacitor C22, a common mode inductor L4, and three filter capacitors C23, C24, and C2.

[0101] The cathode of the fast recovery diode D7 is connected to the first terminal of the first secondary winding of the flyback transformer, and the anode is connected to the first winding of the common-mode inductor L4; the second winding of the common-mode inductor L4 is connected to the second terminal of the first secondary winding of the flyback transformer.

[0102] An aluminum electrolytic capacitor C22 is connected in parallel with a common-mode inductor L4. The first terminal of the aluminum electrolytic capacitor C22 is connected to the first terminal of the first secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the first secondary winding of the flyback transformer.

[0103] Three filter capacitors C23, C24, and C25 are connected in parallel with aluminum electrolytic capacitor C22 and common-mode inductor L4, respectively. The first terminal of the three filter capacitors C23, C24, and C25 is connected to the first terminal of the first secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the first secondary winding of the flyback transformer. The output power network of the three filter capacitors C23, C24, and C25 is labeled as positive P15_HV_UL and negative GND_UL.

[0104] The voltage output circuit of phase U also includes:

[0105] Resistor R21 and capacitor C21 are connected in parallel with aluminum electrolytic capacitor C22 respectively; the first end of resistor R21 and capacitor C21 is connected to the first end of the first secondary winding of the flyback transformer, and the second end is connected to the second end of the first secondary winding of the flyback transformer.

[0106] A resistor R20 and a capacitor C20 are connected in parallel and in series with the fast recovery diode D7; one end of the resistor R20 is connected to the first end of the first secondary winding of the flyback transformer, and the second end is connected to the first end of the capacitor C20; the second end of the capacitor C20 is connected to the second end of the first secondary winding of the flyback transformer.

[0107] In this embodiment, capacitor C22 in the voltage output circuit of phase U has a filtering and energy storage function after rectifier diode D7, resistor R21 is a current limiting resistor, and the network labels of the output terminals are P15V_HV_UL and GND_UL, respectively.

[0108] V. Voltage Output Circuit of Phase W

[0109] In the specific implementation process, combined with Figure 2 As shown, the voltage output circuit of phase W includes a fast recovery diode D3, an aluminum electrolytic capacitor C14, a common mode inductor L3, and three filter capacitors C16, C17, and C18.

[0110] The anode of the fast recovery diode D3 is connected to the first terminal of the second secondary winding of the flyback transformer, and the cathode is connected to the first winding of the common mode inductor L3; the second winding of the common mode inductor L3 is connected to the second terminal of the second secondary winding of the flyback transformer.

[0111] An aluminum electrolytic capacitor C14 is connected in parallel with a common-mode inductor L3. The first end of the aluminum electrolytic capacitor C14 is connected to the first end of the second secondary winding of the flyback transformer, and the second end is connected to the second end of the second secondary winding of the flyback transformer.

[0112] Three filter capacitors C16, C17, and C18 are connected in parallel with aluminum electrolytic capacitor C14 and common-mode inductor L3, respectively. The first terminal of the three filter capacitors C16, C17, and C18 is connected to the first terminal of the second secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the second secondary winding of the flyback transformer. The output power network of the three filter capacitors C16, C17, and C18 is labeled as positive P15_HV_WL and negative GND_WL.

[0113] The voltage output circuit of phase W also includes:

[0114] Resistor R9 and capacitor C15 are connected in parallel with aluminum electrolytic capacitor C14 respectively; the first end of resistor R9 and capacitor C15 is connected to the first end of the second secondary winding of flyback transformer, and the second end is connected to the second end of the second secondary winding of flyback transformer.

[0115] A resistor R8 and a capacitor C11 are connected in parallel and in series with the fast recovery diode D3; one end of the resistor R8 is connected to the first end of the second secondary winding of the flyback transformer, and the second end is connected to the first end of the capacitor C10; the second end of the capacitor C10 is connected to the second end of the second secondary winding of the flyback transformer.

[0116] In this embodiment, the W-phase capacitor C24 is located after the rectifier diode D3 and has the function of filtering and energy storage. The resistor R9 is a current-limiting resistor. The network labels of the output terminals are P15V_HV_WL and GND_WL, respectively.

[0117] VI. Voltage Output Circuit of Phase V

[0118] In the specific implementation process, combined with Figure 2 As shown, the voltage output circuit of phase V includes a fast recovery diode D1, an aluminum electrolytic capacitor C4, a common mode inductor L2, and three filter capacitors C6, C7, and C8.

[0119] The anode of the fast recovery diode D1 is connected to the first terminal of the third secondary winding of the flyback transformer, and the cathode is connected to the first winding of the common-mode inductor L2; the second winding of the common-mode inductor L2 is connected to the second terminal of the third secondary winding of the flyback transformer.

[0120] An aluminum electrolytic capacitor C4 is connected in parallel with a common-mode inductor L2. The first end of the aluminum electrolytic capacitor C4 is connected to the first end of the third secondary winding of the flyback transformer, and the second end is connected to the second end of the third secondary winding of the flyback transformer.

[0121] Three filter capacitors C6, C7, and C8 are connected in parallel with aluminum electrolytic capacitor C4 and common-mode inductor L2, respectively. The first terminal of the three filter capacitors C6, C7, and C8 is connected to the first terminal of the third secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the second secondary winding of the flyback transformer. The output power network of the three filter capacitors C6, C7, and C8 is labeled as positive P15_HV_VL and negative GND_VL.

[0122] The voltage output circuit of phase V also includes:

[0123] Resistor R4 and capacitor C5 are connected in parallel with aluminum electrolytic capacitor C4 respectively; the first end of resistor R4 and capacitor C5 is connected to the first end of the third secondary winding of flyback transformer, and the second end is connected to the second end of the third secondary winding of flyback transformer.

[0124] A resistor R3 and a capacitor C3 are connected in parallel and in series with the fast recovery diode D1; one end of the resistor R3 is connected to the first end of the third secondary winding of the flyback transformer, and the second end is connected to the first end of the capacitor C3; the second end of the capacitor C3 is connected to the second end of the third secondary winding of the flyback transformer.

[0125] In this embodiment, capacitor C4 at the V-phase terminal is located after rectifier diode D1 and has the function of filtering and energy storage. Resistor R4 is a current-limiting resistor. The network labels at the output terminals are P15V_HV_VL and GND_VL, respectively.

[0126] This invention effectively suppresses common-mode noise through the common-mode inductors in the U-phase, W-phase, and V-phase voltage output circuits. Multi-stage filtering (aluminum electrolytic capacitors and three small capacitors) significantly reduces output ripple and noise, ensuring high stability and low noise in the output voltage. The resistors and capacitors connected in parallel with the aluminum electrolytic capacitors optimize the circuit's damping characteristics, preventing resonance and thus improving the stability of the flyback high-voltage BUCK power supply circuit system. The design of the voltage output circuit guarantees high stability and low noise in the three-phase output, while the consistency of the circuit structure ensures the balance of the three-phase output, further improving the overall performance and reliability of the flyback high-voltage BUCK power supply circuit system.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A flyback high-voltage BUCK power supply circuit system, characterized in that: Including flyback transformers; The primary side of a flyback transformer includes two primary windings and one auxiliary winding, while the secondary side includes three secondary windings; two primary windings are connected in series to form a series primary winding. The series primary winding of the flyback transformer is connected to the high-voltage power input circuit and the step-down and control circuit; The auxiliary winding of the flyback transformer is connected to the auxiliary input circuit; The three secondary windings of the flyback transformer are connected to the voltage output circuits of the U-phase, W-phase, and V-phase, respectively.

2. The flyback high-voltage BUCK power supply circuit system as described in claim 1, characterized in that: The high-voltage power input circuit includes an ultra-fast recovery diode D2, a current-limiting resistor R2, a power inductor L1, and four decoupling capacitors; The anode of the ultrafast recovery diode D2 is connected to the external bus voltage input port, and the cathode is connected to the first end of the current limiting resistor R2. The second end of the current limiting resistor R2 is connected to the input terminal of the power inductor L1. The output terminal of the power inductor L1 is connected in series with four decoupling capacitors C1, C9, C10, and C2. The bus voltage is filtered by the four decoupling capacitors C1, C9, C10, and C2 and then connected to the first end of the primary winding of the flyback transformer.

3. The flyback high-voltage BUCK power supply circuit system as described in claim 2, characterized in that: The auxiliary input circuit includes a current-limiting resistor R7, a Zener diode ZD1, an ultra-fast recovery diode D4, and an aluminum electrolytic capacitor C13; The cathode of the ultrafast recovery diode D4 is connected to the current-limiting resistor R7, and the anode is connected to the first end of the auxiliary winding of the flyback transformer. Zener diode ZD1 is connected in parallel with ultrafast recovery diode D4. The cathode of Zener diode ZD1 is connected to current limiting resistor R7, and the anode is connected to the second end of the auxiliary winding of flyback transformer. An aluminum electrolytic capacitor C13 is connected in parallel with a Zener diode ZD1. The first terminal of the aluminum electrolytic capacitor C13 is connected to a current-limiting resistor R7, and the second terminal is connected to the second terminal of the auxiliary winding of the flyback transformer.

4. The flyback high-voltage BUCK power supply circuit system as described in claim 3, characterized in that: The step-down and control circuit includes the power control chip and its peripheral circuitry; The drain of the power control chip is connected to the second end of the primary winding of the flyback transformer connected in series. The input voltage terminal of the power control chip is connected to the output terminal of the power inductor L1 of the high-voltage power input circuit through six series voltage divider resistors R13, R17, R22, R27, R29, and R31; the anode of the Zener diode ZD3 is connected to the voltage divider resistor R29 through the series resistor R33, and the cathode is connected to the voltage divider resistor R31. A first peripheral circuit, including a parallel Zener diode ZD2 and a parallel capacitor C26, is connected between the FWD pin and the SR pin of the power control chip. The cathode of the Zener diode ZD2 is connected to the FWD pin, and the anode is connected to the SR pin. The first end of the parallel capacitor C26 is connected to the FWD pin, and the second end is connected to the SR pin. The BPP pin of the power control chip is connected to the current-limiting resistor R7 of the auxiliary input circuit; A second peripheral circuit, consisting of a fast recovery diode D6, a fast recovery diode D5, and a voltage divider resistor R28 connected in series, is connected between the BPS and FB pins of the power control chip. The cathode of the fast recovery diode D6 is connected to the BPS pin, and the anode is connected to the anode of the Zener diode D5. The cathode of the Zener diode D5 is connected in series with the voltage divider resistor R28 and then connected to the FB pin. A third peripheral circuit, including a series capacitor C30 and a current-limiting resistor R30, is connected between the IS and FB pins of the power control chip. The first end of capacitor C30 is connected to the IS pin, and the second end is connected in series with the current-limiting resistor R30 and then connected to the FB pin.

5. The flyback high-voltage BUCK power supply circuit system as described in claim 4, characterized in that: An RCD snubber circuit is also connected between the drain of the power control chip and the power inductor L1 of the high-voltage power input circuit.

6. The flyback high-voltage BUCK power supply circuit system as described in claim 4, characterized in that: The output voltage of the power control chip is calculated using the following formula: ； In the formula: This indicates the output voltage of the power control chip; This indicates the voltage at the FB pin of the power control chip; This indicates the resistance value of the current-limiting resistor R30; This indicates the resistance value of the voltage divider resistor R28.

7. The flyback high-voltage BUCK power supply circuit system as described in claim 4, characterized in that: The input voltage of the power control chip is calculated using the following formula: ； In the formula: This indicates the input voltage of the power control chip; This indicates the Zener voltage of the Zener diode ZD3; , , , , , These represent the resistance values ​​of the voltage divider resistors R13, R17, R22, R27, R29, and R31, respectively. This indicates the output of the power inductor L1.

8. The flyback high-voltage BUCK power supply circuit system as described in claim 1, characterized in that: The voltage output circuit of phase U includes a fast recovery diode D7, an aluminum electrolytic capacitor C22, a common mode inductor L4, and three filter capacitors C23, C24, and C2. The cathode of the fast recovery diode D7 is connected to the first terminal of the first secondary winding of the flyback transformer, and the anode is connected to the first winding of the common-mode inductor L4; the second winding of the common-mode inductor L4 is connected to the second terminal of the first secondary winding of the flyback transformer. An aluminum electrolytic capacitor C22 is connected in parallel with a common-mode inductor L4. The first terminal of the aluminum electrolytic capacitor C22 is connected to the first terminal of the first secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the first secondary winding of the flyback transformer. Three filter capacitors C23, C24, and C25 are connected in parallel with aluminum electrolytic capacitor C22 and common-mode inductor L4, respectively. The first terminal of the three filter capacitors C23, C24, and C25 is connected to the first terminal of the first secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the first secondary winding of the flyback transformer.

9. The flyback high-voltage BUCK power supply circuit system as described in claim 1, characterized in that: The voltage output circuit of phase W includes a fast recovery diode D3, an aluminum electrolytic capacitor C14, a common mode inductor L3, and three filter capacitors C16, C17, and C18. The anode of the fast recovery diode D3 is connected to the first terminal of the second secondary winding of the flyback transformer, and the cathode is connected to the first winding of the common mode inductor L3; the second winding of the common mode inductor L3 is connected to the second terminal of the second secondary winding of the flyback transformer. An aluminum electrolytic capacitor C14 is connected in parallel with a common-mode inductor L3. The first end of the aluminum electrolytic capacitor C14 is connected to the first end of the second secondary winding of the flyback transformer, and the second end is connected to the second end of the second secondary winding of the flyback transformer. Three filter capacitors C16, C17, and C18 are connected in parallel with aluminum electrolytic capacitor C14 and common-mode inductor L3, respectively. The first terminal of the three filter capacitors C16, C17, and C18 is connected to the first terminal of the second secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the second secondary winding of the flyback transformer.

10. The flyback high-voltage BUCK power supply circuit system as described in claim 1, characterized in that: The voltage output circuit of phase V includes a fast recovery diode D1, an aluminum electrolytic capacitor C4, a common mode inductor L2, and three filter capacitors C6, C7, and C8. The anode of the fast recovery diode D1 is connected to the first terminal of the third secondary winding of the flyback transformer, and the cathode is connected to the first winding of the common-mode inductor L2; the second winding of the common-mode inductor L2 is connected to the second terminal of the third secondary winding of the flyback transformer. An aluminum electrolytic capacitor C4 is connected in parallel with a common-mode inductor L2. The first end of the aluminum electrolytic capacitor C4 is connected to the first end of the third secondary winding of the flyback transformer, and the second end is connected to the second end of the third secondary winding of the flyback transformer. The three filter capacitors C6, C7, and C8 are connected in parallel with the aluminum electrolytic capacitor C4 and the common mode inductor L2, respectively. The first terminal of the three filter capacitors C6, C7, and C8 is connected to the first terminal of the third secondary winding of the flyback transformer, and the second terminal is connected to the second terminal of the second secondary winding of the flyback transformer.

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