Multi-path isolated power supply circuit of bidirectional isolated converter, Bidirectional isolated converter

Abstract

This invention provides a multi-channel isolated power supply circuit and a bidirectional isolated converter. By adding a second isolation transformer, when an undervoltage is detected at the output voltage VCC_1 of the open winding of the first isolation transformer, rectification is activated to share the load of VCC_1, precisely replenishing and raising the voltage of VCC_1, effectively solving the problem of undervoltage under heavy load on the open winding of the first isolation transformer and maintaining a constant output voltage of VCC_1. By adding a third isolation transformer, when an overvoltage is detected at the output voltage VCC_1 of the open winding of the first isolation transformer, rectification is activated to share the load of VCC_2, enabling the closed winding of the first isolation transformer to have voltage clamping capability, effectively solving the problem of overvoltage under light load on the open winding of the first isolation transformer. This enables stable and balanced output of each voltage under full load conditions, improving the dynamic voltage regulation performance and adaptability of the multi-channel isolated power supply across all operating conditions.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, and in particular to a multi-channel isolated power supply circuit for a bidirectional isolated converter and a bidirectional isolated converter. Background Technology

[0002] Bidirectional isolation converters require multiple independent control power supplies that are isolated from each other and do not share a common ground. In engineering applications, a multi-winding transformer scheme is mostly used to draw power, with each winding corresponding to an independent power supply circuit, thereby achieving synchronous output of multiple isolated power supplies. This scheme has a simple structure, controllable cost, and is easy to mass-produce and implement, and is widely used in mainstream power supply topologies such as forward and flyback converters.

[0003] However, multi-winding power supply in transformers has inherent shortcomings: only a single winding in the entire winding system is incorporated into the feedback voltage regulation closed loop (hereinafter referred to as "closed-loop winding"), while the remaining secondary windings rely on the winding turns ratio and core coupling to achieve passive voltage regulation, which is an open-loop output without closed-loop control (hereinafter referred to as "open-loop winding"). Due to the inherent leakage inductance of the transformer, the energy distribution among the windings is unbalanced, and the circuit cross-regulation performance is poor.

[0004] In actual operating conditions, when the load fluctuates, the output voltage of the open-wound winding is prone to significant deviation. For example... Figure 1 As shown, when the closed winding group Ns_T1 is under heavy load, the duty cycle of the power switch Q1 increases accordingly. If the open winding group Np_T1 is under no-load or light-load conditions at this time, its output supply voltage VCC_1 is prone to overvoltage abnormality. Conversely, if the closed winding group Ns_T1 is under light load, the duty cycle of the power switch Q1 decreases, and the open winding group Np_T1 is connected to a heavy load, which will cause its output supply voltage VCC_1 to be low. In severe cases, the voltage may even drop to an undervoltage state.

[0005] To address the aforementioned overvoltage issue in open-wound windings under light load conditions, existing technologies can mitigate this anomaly to some extent by adding dummy loads, configuring voltage clamping circuits, or installing linear regulators for voltage stabilization compensation. However, existing conventional methods are insufficient to effectively address the undervoltage or even voltage drop issues that occur in closed-wound windings under light load conditions and open-wound windings under heavy load conditions. The underlying mechanism is that when an open-wound winding is under heavy load, the leakage inductance of the transformer winding causes a significant increase in the output voltage spike of the closed-wound winding. After filtering and stabilization at the back end, its average voltage is raised. The voltage stabilization closed loop then adjusts the power switch Q1 to reduce the drive duty cycle to stabilize the closed-loop output voltage. However, the reduced duty cycle directly lowers the output voltage of the open-wound winding. Under heavy load conditions, this voltage drop effect is further aggravated, ultimately creating a vicious cycle of continuously decreasing voltage until it leads to voltage loss.

[0006] The core cause of uneven output in multi-channel isolated power supplies is transformer leakage inductance. Existing technologies employ sandwich layered winding processes to optimize transformer structure, which can reduce leakage inductance to some extent and mitigate the impact of load disturbances on the open-loop output, but cannot completely eliminate the problem at its root. Existing technologies also propose collecting multiple output voltages and using a weighted average as a closed-loop feedback reference to optimize the overall output cross-regulation; and connecting a common-mode inductor in series between the two windings to balance the voltage difference between the closed-loop and open-loop outputs using the magnetic flux coupling characteristics of the common-mode inductor. However, these improvements only achieve localized optimization for specific load conditions. Once the system load fluctuation range expands, the voltage fluctuation amplitude of the open-loop output increases dramatically, still failing to completely solve the industry pain point of poor load dynamic adaptability of multi-channel isolated power supplies. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a multi-channel isolated power supply circuit and a bidirectional isolated converter to achieve stable and balanced output of voltages under full load conditions, and improve the dynamic voltage regulation performance and adaptability of the multi-channel isolated power supply under all operating conditions.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A multi-channel isolation power supply circuit for a bidirectional isolation converter includes a first isolation transformer T1; the primary side of the first isolation transformer T1 has a first closed-loop winding and the secondary side has a first open-loop winding; it also includes a second isolation transformer T2 and a third isolation transformer T3; the primary side of the second isolation transformer T2 has a second closed-loop winding and a single-phase bias excitation limiting device, and the secondary side has a second open-loop winding, a second voltage monitoring and driving circuit, and a second switching circuit; the primary side of the third isolation transformer T3 has a third closed-loop winding, and the secondary side has a single-phase bias excitation limiting device, a third open-loop winding, a third voltage monitoring and driving circuit, and a third switching circuit. One end of the second closed winding group is connected to one end of the first open winding group through a single-phase bias excitation limiting device; one end of the second open winding group is connected to the output terminal of the first open winding group, and the other end is connected to the output terminal of the first open winding group after passing through the second switching circuit and the second voltage monitoring and driving circuit in sequence. One end of the third closed winding group is connected to one end of the first open winding group; one end of the third open winding group is connected to the output terminal of the first open winding group through a single-phase bias excitation limiting device, and the other end is connected to the output terminal of the first open winding group after passing through the third switching circuit and the third voltage monitoring and driving circuit in sequence. When the second voltage monitoring and driving circuit detects that the output voltage of the first open-loop winding is lower than the preset second threshold voltage, it drives the second switching circuit to turn on the second isolation transformer T2 and turn on the output of the second open-loop winding. When the third voltage monitoring and driving circuit detects that the output voltage of the first open winding group is higher than the preset third threshold voltage, it drives the third switching circuit to turn on the third isolation transformer T3 and turn on the output of the third closed winding group.

[0009] Optionally, when the second voltage monitoring and driving circuit detects that the output voltage of the first open-loop winding is higher than the preset second threshold voltage, it drives the second switching circuit to disconnect to turn off the second isolation transformer T2 and cut off the output of the second open-loop winding. When the third voltage monitoring and driving circuit detects that the output voltage of the first open winding group is lower than the preset third threshold voltage, it drives the third switching circuit to disconnect to shut down the third isolation transformer T3 and cut off the output of the third closed winding group.

[0010] Optionally, the turns ratio of the second isolation transformer T2 is greater than the turns ratio of the first isolation transformer T1, but less than twice the turns ratio of the first isolation transformer T1.

[0011] Optionally, the turns ratio of the third isolation transformer T3 is less than or equal to the turns ratio of the first isolation transformer T1, and greater than 0.5 times the turns ratio of the first isolation transformer T1.

[0012] Optionally, the second voltage monitoring and driving circuit and the third voltage monitoring and driving circuit have the same circuit structure, both of which include two voltage detection resistors, a precision voltage regulator and a transistor. After the two voltage sensing resistors are connected in series, one end of the series branch is connected to the output terminal of the first open-wound group, and the other end is connected to the anode of the precision voltage regulator. The series node is connected to the reference terminal of the precision voltage regulator. The anode of the precision voltage regulator is grounded, and the cathode is connected to the output terminal of the first open-wound group and the base of the transistor, respectively. The emitter of the transistor is connected to the output terminal of the first open-wound group, and the collector of the transistor is split into two paths, one of which is connected to the anode of the precision voltage regulator, and the other is used as the drive output terminal.

[0013] Optionally, the second voltage monitoring and driving circuit and the third voltage monitoring and driving circuit each further include a current limiting resistor and a drive pull-down resistor; The cathode of the precision voltage regulator is connected to the output terminal of the first open-loop winding via the current-limiting resistor; the collector of the transistor is connected to the anode of the precision voltage regulator via the drive pull-down resistor.

[0014] Optionally, the second switching circuit and the third switching circuit have the same circuit structure, both including a driving resistor and a MOSFET; The drive output terminal is connected to the gate of the MOS transistor via the drive resistor; the source of the MOS transistor is grounded, and the drain serves as the output terminal.

[0015] Optionally, the single-phase bias excitation limiting device is one or more combinations of diodes, unidirectional thyristors, unidirectional synchronous rectifier switches, and unidirectional power transistors.

[0016] Optionally, one end of the second open-wound group is connected to the output terminal of the first open-wound group via a rectifier diode; One end of the third closed winding is connected to one end of the first closed winding via a rectifier diode.

[0017] Another technical solution provided by this invention is: A bidirectional isolation converter, including the multi-channel isolated power supply circuit of the bidirectional isolation converter described above.

[0018] The beneficial effects of this invention are as follows: Addressing the technical problem of uncontrolled output voltage in non-feedback closed-loop windings of multi-winding structures, this invention adds a second isolation transformer T2. When an undervoltage is detected at the open-loop output terminal voltage VCC_1 of the original isolation transformer (first isolation transformer T1), rectification is initiated to aggregate its output to the open-loop output terminal of the first isolation transformer T1, thereby raising the open-loop output voltage VCC_1 of the first isolation transformer T1. This enables the open-loop of the first isolation transformer T1 to have output voltage regulation capability, effectively solving the problem of voltage drop in the open-loop of the first isolation transformer T1 under heavy load, and ensuring the first isolation transformer T1's voltage regulation capability. The output voltage of the open winding of isolation transformer T1 is stable and controllable. Meanwhile, by adding a third isolation transformer T3, when an overvoltage is detected at the output voltage VCC_1 of the open winding of the first isolation transformer T1, rectification is started to summarize its output to the output of the closed winding of the first isolation transformer T1, thereby raising the output voltage VCC_2 of the closed winding of the first isolation transformer T1. This enables the closed winding of the first isolation transformer T1 to have voltage clamping capability, effectively solving the overvoltage output condition of the open winding of the first isolation transformer T1 under light load. Ultimately, the overall output voltage of the first isolation transformer T1 is stable and controllable, improving the reliability of the circuit. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the circuit structure of the multi-channel isolated power supply circuit in an existing bidirectional isolation converter; Figure 2 This is a schematic diagram of the circuit structure of the second isolation transformer T2 in an embodiment of the present invention; Figure 3 This is a schematic diagram of the circuit structure of the third isolation transformer T3 in this embodiment of the invention; Figure 4 This is a schematic diagram of the circuit structure of the multi-channel isolated power supply circuit in the bidirectional isolation converter provided in an embodiment of the present invention. Detailed Implementation

[0020] To explain in detail the technical principles, specific implementable solutions, possible application scenarios, and achievable objectives and effects of the present invention, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. It is understood that the embodiments described herein and the embodiments shown in the accompanying drawings are only used to more clearly illustrate the technical solutions of the present invention, and are therefore only examples intended to explain the present invention, and should not be construed as limiting the present invention. It should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0021] Please see Figures 1 to 4 This invention provides a multi-channel isolation power supply circuit for a bidirectional isolation converter, aiming to specifically solve the technical problem of uncontrolled output voltage of the non-feedback closed winding in a multi-winding structure. This solution adds two isolation transformers (a second isolation transformer T2 and a third isolation transformer T3), using their two windings to deeply couple the closed and open windings of the original isolation transformer (the first isolation transformer T1). Simultaneously, with real-time monitoring of the open winding output voltage, the on / off state of the newly added isolation transformer (the second isolation transformer T2 or the third isolation transformer T3) is precisely controlled. This effectively eliminates interference from load changes in the open winding output voltage, ensuring that the open winding output voltage remains stable and controllable, thus improving the operational stability and reliability of the bidirectional isolation converter.

[0022] This invention provides a multi-channel isolation power supply circuit for a bidirectional isolation converter, wherein the bidirectional isolation transformer is configured as follows: Figure 1 The most common multi-winding output flyback transformer shown is used as an example for illustration.

[0023] Please combine Figure 1 and Figure 4 To understand this, the multi-channel isolated power supply circuit includes the original first isolation transformer T1. The primary side of the first isolation transformer T1 has a first closed-loop winding Ns_T1, and the secondary side has a first open-loop winding Np_T1.

[0024] (1) For the working condition where the open winding of the first isolation transformer T1 cannot be overloaded and the voltage drops (the worst working condition is that the open winding of the first isolation transformer T1 is fully loaded and the closed winding is unloaded at the same time).

[0025] Please combine Figure 2 and Figure 4 To understand this, in this embodiment, a second isolation transformer T2 is added to the multi-channel isolated power supply circuit.

[0026] like Figure 2 As shown, the primary side of the second isolation transformer T2 is provided with a second closed winding group Ns_T2 and a single-phase bias excitation limiting device, and the secondary side is provided with a second open winding group Np_T2, a second voltage monitoring and driving circuit and a second switching circuit.

[0027] Among them, one end of the second closed loop group Ns_T2 (specifically) Figure 2 The terminal with the same name shown is connected to one end of the first closed winding group Ns_T1 through a single-phase bias excitation limiting device (specifically, as shown in the figure). Figure 1 The connection shown is the same name terminal (the specific access point is...). Figure 1 (as shown in NS_VCC2+). The single-phase bias excitation limiting device can conduct unidirectionally and apply a directional magnetic bias to the transformer winding, thereby locking the excitation current flow direction and limiting the excitation source. Here, by setting the single-phase bias excitation limiting device on one side of the first closed winding group Ns_T1, the second closed winding group Ns_T2 of the second isolation transformer T2 is limited to be excited through the first closed winding group Ns_T1 of the first isolation transformer T1. That is, the output of the first closed winding group Ns_T1 provides excitation energy for the second closed winding group Ns_T2, ensuring that the second isolation transformer T2 can operate stably.

[0028] Among them, one end of the second open-loop group Np_T2 (specifically) Figure 2 The terminal with the same name shown is connected to the output terminal VCC_1 of the first open-wrap group Np_T1 (the specific connection point is...). Figure 1 As shown in the diagram, the other end of the transformer (Np_VCC1+) is connected to the output terminal VCC_1 of the first open-wound group Np_T1 after passing through the second switching circuit and the second voltage monitoring and driving circuit. In other words, the output of the second open-wound group Np_T2 of the second isolation transformer T2 is combined with the output of the first open-wound group Np_T1 of the first isolation transformer T1.

[0029] In this embodiment, the working principle of the second isolation transformer T2 is as follows: When the first closed winding Ns_T1 of the first isolation transformer T1 is lightly loaded and the first open winding Np_T1 is heavily loaded, the voltage VCC_1 at the output terminal of the first open winding Np_T1 drops. The second voltage monitoring and driving circuit in the second isolation transformer T2, responsible for real-time monitoring of the voltage value of VCC_1 at the output terminal of the first open winding Np_T1, will drive the second switching circuit to conduct once it detects that the output voltage VCC_1 is lower than the preset first threshold voltage VTH1, thus starting the second isolation transformer T2 for rectification and output, and turning on the output of the second open winding Np_T2. After the second isolation transformer T2 starts working, the output of its second open winding group Np_T2 will be connected to the output terminal VCC_1 of the first open winding group Np_T1. At this time, the second open winding group Np_T2 of the second isolation transformer T2 will share the load of the output terminal VCC_1 with the first open winding group Np_T1 of the first isolation transformer T1. Since the second open winding group Np_T2 is powered by the first closed winding group Ns_T1, its load-carrying capacity is equivalent to helping to share the load pressure of the first closed winding group Ns_T1, effectively improving the load-carrying capacity of the first open winding group Np_T1 of the first isolation transformer T1.

[0030] When the second voltage monitoring and driving circuit detects that the voltage value of VCC_1 at the output terminal of the first open-wound group Np_T1 is higher than the preset second threshold voltage VTH2, it drives the second switching circuit to disconnect, shutting down the second isolation transformer T2 and cutting off the output of the second open-wound group Np_T2. After the second isolation transformer T2 stops working, only the first open-wound group Np_T1 of the first isolation transformer T1 independently bears the load of the output terminal VCC_1, and the output terminal VCC_1 voltage value drops accordingly; when it drops below the preset second threshold voltage VTH2 again, the second isolation transformer T2 will automatically restart to rectify and compensate the voltage at the output terminal VCC_1, thus dynamically adjusting the output of the first open-wound group Np_T1 of the first isolation transformer T1 in a cycle to stably maintain the output voltage of the output terminal VCC_1.

[0031] In this embodiment, by adding a second isolation transformer T2, deep coupling can be achieved between the first open-loop winding Np_T1 and the first closed-loop winding Ns_T1 of the original first isolation transformer T1. When the first open-loop winding Np_T1 is under heavy load, closed-loop feedback control can be formed, prompting the power switching transistors (i.e.,...) in the bidirectional isolation converter to... Figure 1 The duty cycle of the power switch Q1 in the circuit is adaptively increased, which completely overcomes the defect of existing technology that would reduce the duty cycle of the power switch and aggravate the voltage drop of the output VCC_1. It effectively solves the problem of voltage drop and poor adaptability of the first open winding group Np_T1 of the first isolation transformer T1 under heavy load conditions.

[0032] (2) For the overvoltage condition caused by the inability of the open winding of the first isolation transformer T1 to output light load (the worst condition is that the open winding is unloaded and the closed winding is fully loaded at the same time).

[0033] Please combine Figure 3 and Figure 4 To understand this, a third isolation transformer T3 is added to the multi-channel isolated power supply circuit.

[0034] like Figure 3 As shown, the primary side of the third isolation transformer T3 is provided with a third closed winding group Ns_T3, and the secondary side is provided with a single-phase bias excitation limiting device, a third open winding group Np_T3, a third voltage monitoring and driving circuit, and a third switching circuit.

[0035] Among them, one end of the third closed loop group Ns_T3 (specifically) Figure 3 The terminal with the same name shown is connected to one end of the first closed winding group Ns_T1 (specifically, the terminal with the same name shown in 1). One end of the third open winding group Np_T3 (specifically...) is connected to... Figure 3 The terminal shown (with the same name) is connected to the output terminal VCC_1 of the first open winding group Np_T1 via a single-phase bias excitation limiting device (the specific connection point is...). Figure 1 (NP_VCC1+ shown). Here, by setting the single-phase bias excitation limiting device on the side of the first open winding group Np_T1, the third open winding group Np_T3 of the third isolation transformer T3 is limited to be energized through the first open winding group Np_T1 of the first isolation transformer T1. That is, the output of the first open winding group Np_T1 provides excitation energy for the third open winding group Np_T3, ensuring that the third isolation transformer T3 can operate stably.

[0036] The other end of the third open winding group Np_T3 (specifically...) Figure 3 The output of the third closed winding Ns_T3 of the third isolation transformer T3 is connected to the output of the first open winding Np_T1 via the third switching circuit and the third voltage monitoring and driving circuit. In other words, the output of the third closed winding Ns_T3 of the third isolation transformer T3 is combined with the output of the first closed winding Ns_T1 of the first isolation transformer T1.

[0037] In this embodiment, the working principle of the third isolation transformer T3 is as follows: When the first closed winding Ns_T1 of the first isolation transformer T1 is heavily loaded and the first open winding Np_T1 is lightly loaded, the voltage VCC_1 at the output terminal of the first open winding Np_T1 increases. The third voltage monitoring and driving circuit in the third isolation transformer T3, which is responsible for real-time monitoring of the voltage value of VCC_1 at the output terminal of the first open winding Np_T1, will drive the third switching circuit to conduct once it detects that the voltage value of VCC_1 at the output terminal is higher than the preset second threshold voltage VTH2, thereby starting the third isolation transformer T3 to perform rectification and output, and turning on the output of the third closed winding Ns_T3. After the third isolation transformer T3 is energized, the output of its third closed winding Ns_T3 will be connected to the output terminal VCC_2 of the first closed winding Ns_T1. At this time, the third closed winding Ns_T3 of the third isolation transformer T3 and the first closed winding Ns_T1 of the first isolation transformer T1 share the load of the output terminal VCC_2. Since the third closed winding Ns_T3 is powered by the first open winding Np_T1, the voltage of the output terminal VCC_1 will be raised, which will synchronously raise the output voltage of the third closed winding Ns_T3 and the output terminal VCC_2, thereby feedback regulating the power switching transistors (i.e., the power switches) of the bidirectional isolation converter. Figure 1 The power switch Q1 in the circuit reduces its duty cycle, ultimately suppressing and lowering the output voltage VCC_1 of the first open winding group Np_T1, achieving overvoltage fall-off and voltage clamping effects, effectively solving the problem of output overvoltage and uncontrolled voltage under light load conditions in traditional multi-winding isolation converters.

[0038] When the third voltage monitoring and drive circuit detects that the output voltage VCC_1 of the first open-loop winding Np_T1 is lower than the preset third threshold voltage VTH3, it drives the third switching circuit to disconnect, shutting down the third isolation transformer T3 and cutting off the output of the third closed-loop winding Ns_T3. After the third isolation transformer T3 stops working, only the first closed-loop winding Ns_T1 of the first isolation transformer T1 independently bears the load of the output VCC_2. When the first closed-loop winding Ns_T1 of the first isolation transformer T1 is under load again, causing the output voltage of the output VCC_1 to rise above the preset second threshold voltage VTH2, the third isolation transformer T3 will be automatically restarted to rectify and compensate the voltage of the output VCC_2. In this way, the output of the first closed-loop winding Ns_T1 of the first isolation transformer T1 is dynamically adjusted in a cycle to stably maintain the output voltage of the output VCC_2.

[0039] In this embodiment, by adding a third isolation transformer T3, deep coupling can be achieved between the first open-loop winding Np_T1 and the first closed-loop winding Ns_T1 of the original first isolation transformer T1. When the first closed-loop winding Ns_T1 is operating at full load, closed-loop feedback control can be formed, prompting the power switching transistors (i.e.,...) in the bidirectional isolation converter to... Figure 1The duty cycle of the power switch Q1 in the first isolation transformer T1 is adaptively reduced, which completely overcomes the defect of existing technology that increases the duty cycle of the power switch and further raises the output voltage VCC_2. This effectively solves the problem that the first open winding Np_T1 of the first isolation transformer T1 is prone to output overvoltage and poor adaptability under light load conditions.

[0040] In some specific implementations, both the second isolation transformer T2 and the third isolation transformer T3 are low-voltage isolation transformers. Their operating switching frequency is the same as that of the original high-voltage isolation transformer (the first isolation transformer T1), but their core cross-sectional area and volume are smaller, resulting in lower production costs. Their leakage inductance is much lower than that of the high-voltage transformer, their winding coupling performance is better, and their winding output voltage can accurately match the turns ratio and follow the closed-loop control reference voltage VCC_2 well.

[0041] In some specific implementations, the second threshold voltage VTH2 is greater than the first threshold voltage VTH1, ensuring that the two circuits of the second isolation transformer T2 and the third isolation transformer T3 do not affect each other.

[0042] In some specific embodiments, the single-phase bias excitation limiting device may be selected from one or more combinations of diodes, unidirectional thyristors, unidirectional synchronous rectifier switches, and unidirectional power transistors.

[0043] As a specific example, the single-phase bias excitation limiting device located on the primary side of the second isolation transformer T2 is a unidirectional rectifier diode D4; the anode of the unidirectional rectifier diode D4 is connected to the output terminal VCC_2 (specifically as follows). Figure 4 The first closed winding of the first isolation transformer T1 is connected to the same-name terminal, and the anode is connected to one end of the second open winding Np_T2 (specifically as shown in the figure). Figure 4 (The terminals with the same name shown are connected). Here, the current of the first closed winding Ns_T1 of the first isolation transformer T1 is limited by the unidirectional rectifier diode D4 to flow to the second isolation transformer T2, providing it with an excitation source.

[0044] As a specific example, the single-phase bias excitation limiting device located on the secondary side of the third isolation transformer T3 is a unidirectional rectifier diode D5; the anode of the unidirectional rectifier diode D5 is connected to the output terminal VCC_1 (specifically as follows). Figure 4 The first open winding of the first isolation transformer T1 is connected to the same-name terminal, and the anode is connected to one end of the third open winding Np_T3 (specifically as shown in the figure). Figure 4 The terminals shown are connected. Here, the current of the first open winding Np_T1 of the first isolation transformer T1 is limited by the unidirectional rectifier diode D5 to flow to the third isolation transformer T3, providing it with an excitation source.

[0045] As described above, this embodiment addresses two types of operating conditions caused by the leakage inductance characteristics of traditional isolation transformers by setting corresponding dynamic voltage regulation compensation circuits. For the condition where the open winding of the first isolation transformer T1 experiences a voltage drop due to heavy load, a second isolation transformer T2 is added. Its second open winding, Np_T2, shares the output load, precisely replenishing and raising the dropped VCC_1 voltage to maintain a constant output VCC_1 voltage. For the condition where the open winding of the first isolation transformer T1 experiences overvoltage due to light load, a third isolation transformer T3 is added. Its third closed winding, Ns_T3, shares the load, precisely and effectively clamping and stabilizing the overshoot voltage to maintain a constant output VCC_2 voltage. Thus, the multi-channel isolation power supply circuit of the bidirectional isolation converter provided in this embodiment can achieve dynamic correction and stable control of the open winding output voltage under any operating conditions, including no-load, light-load, heavy-load, and full-load conditions, maintaining stable output voltage.

[0046] Please see Figures 1 to 4 Another embodiment of the present invention is a further extension based on the above embodiments.

[0047] like Figure 2 As shown, in the second isolation transformer T2, the second voltage monitoring and driving circuit specifically includes voltage detection resistors R1 and R2, a precision voltage regulator U1, and a transistor Q3.

[0048] Specifically, after voltage sensing resistors R1 and R2 are connected in series, one end of the series branch is connected to the output terminal VCC_1 of the first open-loop winding Np_T1, and the other end is connected to the anode of the precision voltage regulator U1. The series node is connected to the reference terminal of the precision voltage regulator U1. The anode of the precision voltage regulator U1 is grounded, and the cathode is connected to the output terminal VCC_1 of the first open-loop winding Np_T1 and the base of the transistor Q3, respectively. The emitter of the transistor Q3 is connected to the output terminal VCC_1 of the first open-loop winding Np_T1. The collector of the transistor Q3 is split into two paths, one of which is connected to the anode of the precision voltage regulator U1, and the other path serves as the drive output terminal of the second voltage monitoring and drive circuit, which is connected to the second switching circuit.

[0049] In some specific implementations, the first threshold voltage VTH1 is set to 2.5(R1+R2) / R1.

[0050] In some specific embodiments, the second voltage monitoring and driving circuit further includes a current-limiting resistor R10 and a drive pull-down resistor R11. The cathode of the precision voltage regulator U1 is connected to the output terminal VCC_1 of the first open-loop winding Np_T1 via the current-limiting resistor R10; the collector of the transistor Q3 is connected to the anode of the precision voltage regulator U1 via the drive pull-down resistor R11.

[0051] Optionally, the precision voltage regulator U1 is a high-precision programmable reference voltage source of model TL431. The transistor Q3 is a PNP transistor.

[0052] The working principle of the second voltage monitoring and driving circuit is as follows: When the output voltage VCC_1 of the first open-loop winding Np_T1 is lower than the preset first threshold voltage VTH1=2.5(R1+R2) / R1, the precision regulator U1 is turned off, the transistor Q3 is turned off, and the output low level is sent to the second switching circuit, driving the second switching circuit to conduct and starting the second isolation transformer T2 for rectification output.

[0053] When the output voltage VCC_1 of the first open-loop winding Np_T1 is higher than the preset first threshold voltage VTH1=2.5(R1+R2) / R1, the precision regulator U1 is turned on, and the transistor Q3 is turned on accordingly, outputting a high level to the second switching circuit, driving the second switching circuit to turn off, shutting down the second isolation transformer T2, and prohibiting its rectified output.

[0054] like Figure 2 As shown, in the second isolation transformer T2, the second switching circuit specifically includes a drive resistor R12 and a MOSFET Q2. The drive output terminal of the second voltage monitoring and drive circuit is connected to the gate of the MOSFET Q2 via the drive resistor R12; the source of the MOSFET Q2 is grounded, and the drain serves as the output terminal of the second switching circuit, connected to one end of the second open-circuit winding Np_T2 (specifically, the opposite-named terminal shown in the figure).

[0055] In some specific embodiments, the MOS transistor Q2 is a low-voltage P-channel MOS transistor.

[0056] The working principle of the second switching circuit is as follows: When the voltage value of VCC_1 at the output terminal of the first open-loop winding Np_T1 is lower than the preset first threshold voltage VTH1=2.5(R1+R2) / R1, the low level output by the second voltage monitoring and driving circuit drives the MOS transistor Q2 to conduct after passing through the driving resistor R12, and starts the second isolation transformer T2 to perform rectification output.

[0057] When the voltage value of VCC_1 at the output terminal of the first open-loop winding Np_T1 is higher than the preset first threshold voltage VTH1=2.5(R1+R2) / R1, the high level output of the second voltage monitoring and driving circuit drives the MOS transistor Q2 to turn off after passing through the driving resistor R12, thereby shutting down the second isolation transformer T2 and prohibiting its rectified output.

[0058] In some specific embodiments, one end of the second open-wrap group Np_T2 (specifically, as shown in the example) Figure 4 The terminal with the same name shown is connected to the output terminal VCC_1 of the first open-wound group Np_T1 via a rectifier diode D3.

[0059] In this embodiment, the working principle of the second isolation transformer T2 is as follows: When the voltage value of VCC_1 at the output terminal of the first open-wound group Np_T1 is lower than the first threshold voltage VTH1=2.5(R1+R2) / R1, the precision regulator U1 is turned off, and the transistor Q3 is also turned off, resulting in a low-level output. This low-level voltage, after passing through the drive resistor R12, drives the MOSFET Q2 to conduct, starting the second isolation transformer T2 for rectification. The output of its second open-wound group Np_T2 is then connected to the output terminal VCC_1 of the first open-wound group Np_T1 to share the load on output terminal VCC_1. Since the second open-wound group Np_T2 is powered by the first closed-wound group Ns_T1 of the first isolation transformer T1, the load on the second open-wound group Np_T2 is equivalent to the load on the first closed-wound group Ns_T1, causing the power switching transistor (i.e., the first closed-wound group Ns_T1) in the first isolation transformer T1 to be activated. Figure 1 The duty cycle of the power switch Q1 in the first isolation transformer T1 is increased to improve the load-carrying output capability of the first open winding Np_T1 and suppress the output voltage drop under heavy load conditions.

[0060] When the output voltage VCC_1 of the first open-wound group Np_T1 is higher than the first threshold voltage VTH1 = 2.5(R1+R2) / R1, the precision regulator U1 turns on, and the transistor Q3 turns on accordingly, outputting a high level. The high level drives the MOSFET Q2 to turn off after passing through the drive resistor R12, shutting down the second isolation transformer T2 and cutting off its rectified output. The first open-wound group Np_T1 of the first isolation transformer T1 then resumes to independently bear the load of the output VCC_1, and the output voltage VCC_1 subsequently drops back.

[0061] like Figure 3 As shown, in the third isolation transformer T3, the third voltage monitoring and driving circuit specifically includes voltage detection resistors R3 and R4, a precision voltage regulator U2, and a transistor Q5.

[0062] Specifically, after voltage sensing resistors R3 and R4 are connected in series, one end of the series branch is connected to the output terminal VCC_1 of the first open-loop winding Np_T1, and the other end is connected to the anode of the precision voltage regulator U2. The series node is connected to the reference terminal of the precision voltage regulator U2. The anode of the precision voltage regulator U2 is grounded, and the cathode is connected to the output terminal VCC_1 of the first open-loop winding Np_T1 and the base of the transistor Q5, respectively. The emitter of the transistor Q5 is connected to the output terminal VCC_1 of the first open-loop winding Np_T1. The collector of the transistor Q5 is split into two paths, one of which is connected to the anode of the precision voltage regulator U2, and the other path serves as the drive output terminal of the third voltage monitoring and drive circuit, which is connected to the third switching circuit.

[0063] In some specific implementations, the second threshold voltage VTH2 is set to 2.5*(R3+R4) / R3.

[0064] In some specific embodiments, the third voltage monitoring and driving circuit further includes a current-limiting resistor R20 and a drive pull-down resistor R21. The cathode of the precision voltage regulator U2 is connected to the output terminal VCC_1 of the first open-loop winding Np_T1 via the current-limiting resistor R20; the collector of the transistor Q5 is connected to the anode of the precision voltage regulator U2 via the drive pull-down resistor R21.

[0065] Optionally, the precision voltage regulator U2 is a high-precision programmable reference voltage source of model TL431. The transistor Q5 is a PNP transistor.

[0066] The working principle of the third voltage monitoring and driving circuit is as follows: When the output voltage VCC_1 of the first open-loop winding Np_T1 is higher than the preset second threshold voltage VTH2=2.5*(R3+R4) / R3, the precision regulator U2 is turned on, the transistor Q5 is turned on, and the output high level is sent to the third switching circuit, which drives the third switching circuit to turn on and starts the third isolation transformer T3 for rectification output.

[0067] When the output voltage VCC_1 of the first open-loop winding Np_T1 is lower than the preset second threshold voltage VTH2=2.5*(R3+R4) / R3, the precision regulator U2 is turned off, the transistor Q5 is turned off, and the output low level is sent to the third switching circuit, driving the third switching circuit to open, shutting down the third isolation transformer T3, and prohibiting its rectification output.

[0068] like Figure 3As shown, in the third isolation transformer T3, the third switching circuit specifically includes a drive resistor R22 and a MOSFET Q4. The drive output terminal of the third voltage monitoring and drive circuit is connected to the gate of the MOSFET Q4 via the drive resistor R22; the source of the MOSFET Q4 is grounded, and the drain serves as the output terminal of the third switching circuit, connected to one end of the third open-circuit winding Np_T3 (specifically, as shown in the diagram). Figure 3 Connect the different-named ends shown.

[0069] In some specific embodiments, the MOS transistor Q4 is a low-voltage P-channel MOS transistor.

[0070] The working principle of the third switching circuit is as follows: When the output voltage VCC_1 of the first open-loop winding Np_T1 is higher than the preset second threshold voltage VTH2=2.5*(R3+R4) / R3, the high level output of the third voltage monitoring and driving circuit drives the MOS transistor Q2 to conduct after passing through the driving resistor R22, and conducts the rectification output of the third isolation transformer T3.

[0071] When the voltage value of VCC_1 at the output terminal of the first open-loop winding Np_T1 is lower than the preset second threshold voltage VTH2=2.5*(R3+R4) / R3, the low level output by the third voltage monitoring and driving circuit drives the MOS transistor Q4 to turn off after passing through the driving resistor R22, shutting down the third isolation transformer T3 and prohibiting its rectification output.

[0072] In some specific embodiments, one end of the third closed loop group Ns_T3 (specifically, as shown in the figure) Figure 4 The terminal with the same name shown is connected to the output terminal VCC_2 of the first closed winding group Ns_T1 via a rectifier diode D6.

[0073] In this embodiment, the working principle of the third isolation transformer T3 is as follows: When the voltage at the output terminal VCC_1 of the first open-wound group Np_T1 is higher than VTH2 = 2.5 * (R3 + R4) / R3, the precision regulator U2 turns on, and the transistor Q5 turns on accordingly, outputting a high level. This high level, after passing through the drive resistor R22, drives the MOSFET Q4 to turn on, starting the third isolation transformer T3 for rectification. The output of its third closed-wound group Ns_T3 is then connected to the output terminal VCC_2 of the first closed-wound group Ns_T1, sharing the load on output terminal VCC_2. Since the third closed-wound group Ns_T3 draws power from the first open-wound group Np_T1, the load on the third closed-wound group Ns_T3 is equivalent to the load on the first open-wound group Np_T1, causing the power switch transistor (i.e., the first open-wound group Np_T1) in the first isolation transformer T1 to... Figure 1When the duty cycle of the power switch Q1 in the circuit is reduced, the voltage at the output terminal VCC_1 of the corresponding first open-circuit group Np_T1 will decrease, achieving overvoltage fall-off and voltage clamping effects.

[0074] When the output voltage VCC_1 of the first open-wound group Np_T1 is lower than VTH2 = 2.5 * (R3 + R4) / R3, the precision regulator U2 is turned off, and the transistor Q5 is also turned off, resulting in a low-level output. This low-level voltage, after passing through the drive resistor R22, drives the MOSFET Q4 to turn off, shutting down the third isolation transformer T3 and cutting off its rectified output. The first closed-wound group Ns_T1 of the first isolation transformer T1 then resumes its independent load on the output VCC_2.

[0075] In this embodiment, the second voltage monitoring and driving circuit and the third voltage monitoring and driving circuit have the same circuit structure, both including two voltage detection resistors, a precision voltage regulator, a transistor, a current-limiting resistor, and a drive pull-down resistor. The second switching circuit and the third switching circuit have the same circuit structure, both including a drive resistor and a MOSFET. Here, the voltage monitoring and driving circuit and the switching circuit in the second isolation transformer T2 and the third isolation transformer T3 are specially designed to have a unified circuit structure and highly compatible control logic; this not only effectively improves the stability of circuit operation, but also reduces the types of components and compresses design and material costs through standardized circuit architecture; at the same time, it also has the advantages of strong structural versatility, facilitating mass production assembly and subsequent fault diagnosis and maintenance.

[0076] Another embodiment of the present invention is a further extension based on any of the above embodiments.

[0077] In this embodiment, the turns ratio Np_T2 / Ns_T2 of the second isolation transformer T2 is specially designed to be slightly larger than VCC_1 / VCC_2.

[0078] Since the turns ratio of the first isolation transformer T1 is Np_T1 / Ns_T1 = VCC_1 / VCC_2, the turns ratio of the second isolation transformer T2, Np_T2 / Ns_T2, can be directly set to be slightly larger than the turns ratio of the first isolation transformer T1, Np_T1 / Ns_T1, but less than twice the turns ratio of the first isolation transformer T1.

[0079] The specific ratio range depends on the actual load of the first open winding group Np_T1 of the first isolation transformer T1. The larger the load of the first open winding group Np_T1, the higher the ratio, and the smaller the load, the lower the ratio.

[0080] In some specific implementations, it is preferred that Np_T2 / Ns_T2 = (1.1~1.2)*(VCC_1 / VCC_2); that is, Np_T2 / Ns_T2 = (1.1~1.2)* Np_T1 / Ns_T1.

[0081] This embodiment, by reasonably matching the primary and secondary turns ratios of the first isolation transformer T1 and the second isolation transformer T2, not only allows for better adjustment of the duty cycle of the second switching circuit (specifically, MOSFET Q2) of the second isolation transformer T2, but also ensures that the output voltage VCC_1 of the first open-loop winding Np_T1 does not trigger overvoltage protection when the second switching circuit (specifically, MOSFET Q2) is normally on. Even in the event of a single-point failure due to a short circuit in the second switching circuit, the circuit can still operate stably. Therefore, by equipping the second isolation transformer T2 with a miniature closed-loop voltage regulation mechanism in the open-loop winding of the multi-channel isolated power supply circuit, the output voltage VCC_1 regulation accuracy is effectively improved. Compared to the traditional open-loop voltage control scheme that relies solely on turns ratio voltage regulation, this significantly enhances the stability and reliability of output voltage regulation.

[0082] In this embodiment, the turns ratio Np_T3 / Ns_T3 of the third isolation transformer T3 is specifically designed to be slightly smaller than the turns ratio Np_T1 / Ns_T1 of the first isolation transformer T1, but greater than 0.5 times the turns ratio of the first isolation transformer T1.

[0083] Similarly, the specific ratio range depends on the actual load of the first open winding group Np_T1 of the first isolation transformer T1. The larger the load of the first open winding group Np_T1, the smaller the ratio, and the smaller the load, the larger the ratio.

[0084] In some specific implementations, it is preferred that Np_T3 / Ns_T3 = (0.9~1)*(VCC_1 / VCC_2); that is, Np_T3 / Ns_T3 = (0.9~1)*Np_T1 / Ns_T1.

[0085] This embodiment, by reasonably matching the primary and secondary turns ratios of the first isolation transformer T1 and the third isolation transformer T3, will be more conducive to preventing overvoltage and playing a voltage clamping role.

[0086] The multi-channel isolation power supply circuit of the bidirectional isolation converter provided in this embodiment can regulate the target output voltage by reasonably matching the turns ratio between the two added isolation transformers (second isolation transformer T2 and third isolation transformer T3) and the original isolation transformer (first isolation transformer T1). With the help of voltage monitoring and drive circuits and switching circuits, the regulation accuracy of output voltage can be further improved.

[0087] Please see 1 and Figure 4 Based on any of the above embodiments, the present invention also provides a bidirectional isolation converter.

[0088] This embodiment provides a bidirectional isolation converter, including a multi-channel isolation power supply circuit of the bidirectional isolation converter described in any of the above embodiments. The specific structure of the multi-channel isolation power supply circuit is as follows: Figure 4 As shown, details will not be elaborated here; please refer to the description in the above embodiments for more information.

[0089] Bidirectional isolation converters require isolation and insulation on both sides, and the two power supplies do not share a common ground. When the two loads are random and relatively large, conventional multi-winding transformers cannot simultaneously regulate voltage because only one winding voltage is controlled (i.e., the closed winding), while the output of the other uncontrolled winding (i.e., the open winding) fluctuates with its own load or the load of the closed winding. To address this situation, existing multi-channel isolation power supply circuit schemes for bidirectional isolation converters often use two independent power supply circuits, which suffer from drawbacks such as high cost, large size, high losses, and low power density.

[0090] The bidirectional isolation converter in this embodiment is used only in a single circuit ( Figure 1 By adding two small low-voltage isolation transformers (second isolation transformer T2 and third isolation transformer T3) and matching low-voltage devices to the existing structure, the two output voltages can be synchronously controlled, effectively reducing costs and size while improving work efficiency.

[0091] In some specific embodiments, the existing multi-channel isolated power supply circuit, as in any of the above embodiments, i.e., the aforementioned single circuit, is as follows: Figure 1 The diagram shows a classic dual-winding flyback circuit. Power switch Q1 is the power NMOS transistor on the high-voltage side of the first isolation transformer T1; resistor Rn, capacitor Cn, and diode Dn form the RCD clamping circuit for power switch Q1; diode D1 and capacitor C1 are the rectifier diode and output filter capacitor for the first open-loop winding Np_T1; diode D2 and capacitor C2 are the rectifier diode and output filter capacitor for the first closed-loop winding Ns_T1; resistors Rf1 and Rf2 are the voltage feedback resistors for the first closed-loop winding Ns_T1.

[0092] Specifically, signals NP_VCC1+ and NS_VCC2+ are the power draw points for the third isolation transformer T3 circuit structure and the second isolation transformer T2 circuit structure in the above embodiments, respectively. When the power switch Q1 is closed, the primary winding of the first isolation transformer T1 stores energy, and D1 and D2 are both cut off; when the power switch Q1 is open, the high-voltage secondary winding of the first isolation transformer T1 releases energy, and D1 and D2 are rectified and output.

[0093] Those skilled in the art will understand that all or part of the processes in the above technical solutions can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the methods described above. After being executed by a processor, the program can also achieve the beneficial effects of the corresponding methods.

[0094] The storage medium can be a disk, optical disc, read-only memory (ROM), or random access memory (RAM), etc.

[0095] Although preferred embodiments of the invention have been described, those skilled in the art, upon understanding the basic inventive concept, can make other changes and modifications to the embodiments. Therefore, the appended claims are intended to cover the preferred embodiments and all equivalent modifications falling within the scope of protection defined by the claims and their equivalents. Clearly, those skilled in the art can make various alterations and variations to the invention without departing from its spirit and scope. If such modifications and variations fall within the scope of protection defined by the claims and their equivalents, the invention also intends to include them.

[0096] It should be noted that any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware.

[0097] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "multiple" means two or more, unless otherwise explicitly specified. The term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone.

[0098] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0099] In this specification, the use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0100] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A multi-path isolated power supply circuit of a bidirectional isolated converter, comprising a first isolated transformer (T1); a first closed-loop winding is arranged on a primary side of the first isolated transformer (T1), and a first open-loop winding is arranged on a secondary side of the first isolated transformer (T1); characterized in that, It also includes a second isolation transformer (T2) and a third isolation transformer (T3); the primary side of the second isolation transformer (T2) is provided with a second closed winding and a single-phase bias excitation limiting device, and the secondary side is provided with a second open winding, a second voltage monitoring and drive circuit and a second switching circuit; the primary side of the third isolation transformer (T3) is provided with a third closed winding, and the secondary side is provided with a single-phase bias excitation limiting device, a third open winding, a third voltage monitoring and drive circuit and a third switching circuit; One end of the second closed winding group is connected to one end of the first open winding group through a single-phase bias excitation limiting device; one end of the second open winding group is connected to the output terminal of the first open winding group, and the other end is connected to the output terminal of the first open winding group after passing through the second switching circuit and the second voltage monitoring and driving circuit in sequence. One end of the third closed winding group is connected to one end of the first open winding group; one end of the third open winding group is connected to the output terminal of the first open winding group through a single-phase bias excitation limiting device, and the other end is connected to the output terminal of the first open winding group after passing through the third switching circuit and the third voltage monitoring and driving circuit in sequence. When the second voltage monitoring and driving circuit detects that the output voltage of the first open-loop winding is lower than the preset second threshold voltage, it drives the second switching circuit to turn on the second isolation transformer (T2) and turn on the output of the second open-loop winding. When the third voltage monitoring and driving circuit detects that the output voltage of the first open winding group is higher than the preset third threshold voltage, it drives the third switching circuit to turn on the third isolation transformer (T3) and turn on the output of the third closed winding group. The turns ratio of the second isolation transformer (T2) is greater than that of the first isolation transformer (T1), but less than twice the turns ratio of the first isolation transformer (T1); The turns ratio of the third isolation transformer (T3) is less than or equal to the turns ratio of the first isolation transformer (T1), and greater than 0.5 times the turns ratio of the first isolation transformer (T1).

2. The multi-channel isolated power supply circuit of the bidirectional isolation converter as described in claim 1, characterized in that, When the second voltage monitoring and driving circuit detects that the output voltage of the first open-loop winding is higher than the preset second threshold voltage, it drives the second switching circuit to disconnect to shut down the second isolation transformer (T2) and cut off the output of the second open-loop winding. When the third voltage monitoring and driving circuit detects that the output voltage of the first open winding group is lower than the preset third threshold voltage, it drives the third switching circuit to disconnect to shut down the third isolation transformer (T3) and cut off the output of the third closed winding group.

3. The multi-channel isolated power supply circuit of the bidirectional isolation converter as described in claim 1, characterized in that, The second voltage monitoring and driving circuit and the third voltage monitoring and driving circuit have the same circuit structure, both of which include two voltage detection resistors, a precision voltage regulator and a transistor. After the two voltage sensing resistors are connected in series, one end of the series branch is connected to the output terminal of the first open-wound group, and the other end is connected to the anode of the precision voltage regulator. The series node is connected to the reference terminal of the precision voltage regulator. The anode of the precision voltage regulator is grounded, and the cathode is connected to the output terminal of the first open-wound group and the base of the transistor, respectively. The emitter of the transistor is connected to the output terminal of the first open-wound group, and the collector of the transistor is split into two paths, one of which is connected to the anode of the precision voltage regulator, and the other is used as the drive output terminal.

4. The multi-channel isolated power supply circuit of the bidirectional isolation converter as described in claim 3, characterized in that, The second voltage monitoring and driving circuit and the third voltage monitoring and driving circuit both include a current-limiting resistor and a drive pull-down resistor; The cathode of the precision voltage regulator is connected to the output terminal of the first open-loop winding via the current-limiting resistor; the collector of the transistor is connected to the anode of the precision voltage regulator via the drive pull-down resistor.

5. The multi-channel isolated power supply circuit of the bidirectional isolation converter as described in claim 3, characterized in that, The second switching circuit and the third switching circuit have the same circuit structure, both of which include a driving resistor and a MOSFET. The drive output terminal is connected to the gate of the MOS transistor via the drive resistor; the source of the MOS transistor is grounded, and the drain serves as the output terminal.

6. The multi-channel isolated power supply circuit of the bidirectional isolation converter as described in claim 5, characterized in that, The single-phase bias excitation limiting device is one or more combinations of diodes, unidirectional thyristors, unidirectional synchronous rectifier switches, and unidirectional power transistors.

7. The multi-channel isolated power supply circuit of the bidirectional isolation converter as described in claim 1, characterized in that, One end of the second open-wound group is connected to the output terminal of the first open-wound group via a rectifier diode; One end of the third closed winding is connected to one end of the first closed winding via a rectifier diode.

8. A bidirectional isolation converter, characterized in that, The multi-channel isolated power supply circuit includes the bidirectional isolated converter described in any one of claims 1 to 7.

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