Direct current circuit breaker driving power supply circuit based on resonant cavity isolation method

Abstract

The invention discloses a direct-current circuit breaker driving power supply circuit based on a resonant cavity isolation method, relates to the field of power electronics, and is used for improving the isolation voltage-withstanding characteristic and efficiency of the direct-current circuit breaker driving power supply circuit. An input circuit is connected to a voltage source for noise suppression, and a first resonant branch of a power switch circuit and a first resonant branch of a resonant cavity circuit are respectively connected with the input circuit to form a full-bridge structure; a second resonant branch of the resonant cavity circuit is connected with the rectifying circuit and the output filter circuit to form a full-bridge structure, and the rectifying circuit is connected between the two resonant branches; the switch driving circuit generates two paths of reverse complementary PWM driving signals to respectively control the on-off states of two switches in the power switch circuit; and finally, the output filter circuit outputs positive and negative voltages. The resonant cavity is used for high-voltage side and low-voltage side isolation, the circuit size is greatly reduced, the power density is improved, the switching loss is reduced by adopting a resonant transmission mode, and the circuit efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a DC circuit breaker drive power supply circuit based on a resonant cavity isolation method. Background Technology

[0002] In fields such as flexible DC transmission, hydropower unit excitation circuits, and medium- and high-voltage DC distribution networks, hybrid DC circuit breakers, with their synergistic advantages of low on-state losses from mechanical switches and rapid breaking by power semiconductor devices, have become core equipment for solving the problem of DC systems lacking natural zero-crossing points and achieving arc-free short-circuit current interruption. Their performance reliability highly depends on the stability of the power supply driving the power semiconductor devices. The power supply circuit must provide precise drive voltage and sufficient drive current for the core power semiconductor devices such as converter switches and transfer branch switches within the hybrid DC circuit breaker. It must also meet the stringent electrical isolation requirements of the high- and low-voltage sides to prevent energy from the high-voltage side of the DC system from entering the low-voltage control circuit, which could damage the drive chip or disrupt the control signal.

[0003] Currently, power semiconductor drive power supply solutions for hybrid DC circuit breakers still face several insurmountable technical bottlenecks: Traditional power supply methods using industrial frequency isolation transformers, while meeting high-voltage isolation requirements, suffer from large core size and weight, and slow dynamic response, making them unsuitable for the rapid adjustment of drive power supply during fault breaking in hybrid DC circuit breakers, and even more difficult to integrate into the compact design of modular circuit breakers; while magnetically coupled inductor-based isolation solutions effectively reduce size, they carry the risk of core saturation. In typical operating conditions of hybrid DC circuit breakers, voltage spikes generated when the circuit breaker interrupts short-circuit current accelerate the aging process of the insulation layer in the non-resonant isolation circuit, significantly increasing the risk of high- and low-voltage isolation failure; frequent load adjustments require the drive power supply circuit to continuously switch output power, but the dynamic response delay of traditional solutions easily leads to commutation timing disorders in power semiconductor devices, ultimately causing circuit breaker breaking failure.

[0004] Therefore, developing a drive power supply circuit that combines high isolation withstand voltage, high efficiency, and wide operating condition adaptability to meet the drive power supply requirements of power semiconductor devices in hybrid DC circuit breakers has become a key technical direction for overcoming the application limitations of existing hybrid DC circuit breakers and improving their operational reliability. Summary of the Invention

[0005] The purpose of this invention is to provide a DC circuit breaker drive power supply circuit based on a resonant cavity isolation method to address all or part of the problems mentioned above, thereby improving the isolation withstand voltage characteristics and efficiency of the DC circuit breaker drive power supply circuit.

[0006] The technical solution adopted in this invention is as follows: A DC circuit breaker drive power supply circuit based on a resonant cavity isolation method includes: The input circuit has a voltage source connected to its input terminal, and noise suppression is applied to the voltage source. A power switching circuit includes a half-bridge circuit composed of a first switch and a second switch, the half-bridge circuit being connected to the output terminal of the output circuit. The switch driving circuit generates two inversely complementary PWM driving signals, wherein the first driving signal controls the on / off state of the first switch, and the second driving signal controls the on / off state of the second switch. The resonant cavity circuit includes a first resonant branch and a second resonant branch, wherein the first resonant branch is connected to the output terminal of the output circuit, and the second resonant branch is connected between the half-bridge circuit and the output filter circuit. A rectifier circuit is connected between the first resonant branch and the second resonant branch; The output filter circuit is connected to the second resonant branch to generate positive and negative dual output voltages.

[0007] Furthermore, the input circuit includes a common-mode inductor. and capacitor The common-mode inductor The two input terminals are connected to the voltage source, and the two output terminals are connected to the capacitor. in parallel.

[0008] Furthermore, the switch driving circuit includes a dead-time generation circuit; the dead-time generation circuit includes an upper bridge arm and a lower bridge arm, the dead-time generation circuit passes the input PWM signal directly through the upper bridge arm to the first RC delay circuit for delay processing, and outputs the first driving signal; the dead-time generation circuit inverts the PWM signal through the lower bridge arm, and then delays it through the second RC delay circuit, and outputs the second driving signal.

[0009] Furthermore, the PWM signal is generated by an active crystal oscillator.

[0010] Furthermore, the first RC delay circuit includes a resistor. ,capacitance ,diode and inverter The resistor With the inverter The diodes are connected in series. Connected in reverse parallel to the resistor At both ends, the capacitor Connect the resistor Form an RC delay circuit; The second RC delay circuit includes resistors ,capacitance ,diode and inverter The resistor With the inverter The diodes are connected in series. Connected in reverse parallel to the resistor At both ends, the capacitor Connect the resistor An RC delay circuit is formed.

[0011] Furthermore, the first resonant branch includes a capacitor. ,capacitance and inductor The capacitor and capacitor The inductor is connected in series and then in parallel to the output terminal of the input circuit. One end is connected to the capacitor and capacitor Between the two ends, the other end is connected to the rectifier circuit; The second resonant branch includes a capacitor. ,capacitance and inductor The capacitor and capacitor After being connected in series, it is connected in parallel with the rectifier circuit, and the inductor One end is connected to the capacitor and capacitor Between the two ends, the other end is connected to the half-bridge circuit; The capacitor and capacitor Together with the half-bridge circuit, they form a full-bridge structure.

[0012] Furthermore, both the first switch and the second switch are MOSFET switching transistors, and the first switch and the second switch are connected in series and then in parallel to the output terminal of the input circuit; the second resonant branch is connected between the first switch and the second switch.

[0013] Furthermore, the MOSFET switch is a GaN power device.

[0014] Furthermore, the rectifier circuit includes diodes connected in series in the same direction. and diodes The diode and diodes After being connected in series, with the capacitor connected in series and capacitor Parallel connection; the inductor Connected to the diode and diodes between; The diode and diodes With the capacitor and capacitor It constitutes the entire bridge structure.

[0015] Furthermore, the output filter circuit includes an inductor. ,capacitance and capacitor The capacitor and the capacitor After being connected in series, with the capacitor connected in series and capacitor Parallel connection; the inductor One end is connected to the capacitor and the capacitor Between, the other end is connected to the capacitor. and the capacitor Between; the capacitor The capacitor forms a positive voltage output terminal at its two ends. The two ends form a negative voltage output terminal.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The DC circuit breaker drive power supply circuit designed in this application uses a resonant cavity to replace the traditional transformer to achieve isolation. It can achieve high isolation withstand voltage without a transformer, which can significantly reduce the circuit size and weight and increase power density.

[0017] 2. This application uses a resonant transmission method for driving, which reduces switching losses and improves circuit efficiency, making it suitable for high-power, high-frequency power equipment driving power supply scenarios.

[0018] 3. The DC circuit breaker drive power supply circuit designed in this application has a simple structure and high reliability. It can stably output positive and negative dual voltages to meet the drive power supply requirements of power switching devices in DC circuit breakers, converters and other equipment.

[0019] 4. In the DC circuit breaker drive power supply circuit designed in this application, the switching device uses GaN devices, which can achieve a MHz-level operating frequency, thereby reducing the size and weight of the device and increasing the power density. Attached Figure Description

[0020] The present invention will be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a structural diagram of a DC circuit breaker drive power supply circuit based on the resonant cavity isolation method in one embodiment.

[0021] Figure 2This is a circuit diagram of a DC circuit breaker drive power supply circuit based on the resonant cavity isolation method in one embodiment. Detailed Implementation

[0022] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0023] Any feature disclosed in this specification (including any appended claims and abstract) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0024] To address the issues of slow dynamic response speed of traditional DC circuit breaker drive power supply circuits, which make it difficult to adapt to the rapid adjustment requirements of drive power supply during fault disconnection of hybrid DC circuit breakers, and which easily lead to high and low voltage isolation failure and commutation timing disorder of power semiconductor devices, this application proposes a DC circuit breaker drive power supply circuit based on the resonant cavity isolation method, which enables the DC circuit breaker drive power supply circuit to have the characteristics of high isolation withstand voltage and high efficiency.

[0025] like Figure 1 As shown in the embodiments of this application, the DC circuit breaker drive power supply circuit based on the resonant cavity isolation method includes an input circuit, a power switch circuit, a switch drive circuit, a resonant cavity circuit, a rectifier circuit, and an output filter circuit.

[0026] (1) Input circuit.

[0027] The input terminal of the input circuit is responsible for connecting the voltage source. For the connected voltage source Noise suppression is performed. Specifically, this involves suppressing the connected voltage source. Suppress differential mode components and / or common mode components.

[0028] In one alternative implementation, such as Figure 1 As shown, the input circuit includes a common-mode inductor. and capacitor Common mode inductor The two input terminals are connected to a voltage source common mode inductor The two output terminals and the capacitor in parallel.

[0029] A common-mode inductor is also known as a common-mode choke. It can effectively filter voltage sources Common-mode electromagnetic interference signals, also known as common-mode components. Capacitors. This forms an X capacitor, which can effectively filter voltage sources. The differential mode component in.

[0030] (2) Power switching circuit.

[0031] The power switching circuit includes a first switch Second switch This forms a half-bridge circuit, which is connected to the output terminal of the output circuit.

[0032] A half-bridge circuit is a switching circuit in which only one arm is conducting at a time. Therefore, the first switch... Second switch Asynchronous conduction. The first switch can be controlled separately using corresponding drive signals. Second switch The on / off state is adjusted to make it asynchronously conduct.

[0033] In one alternative implementation, such as Figure 2 As shown, the first switch Second switch All circuits employ MOSFET switches, such as NMOS transistors. Furthermore, as a preferred embodiment, the MOSFET switches utilize GaN power devices to achieve high switching frequencies (MHz-level switching frequencies), reducing the size and weight of the switching circuit while increasing power density and ensuring the stability of the drive voltage. The gate of the MOSFET switch is connected to the drive signal; it turns on when the drive signal is high and turns off when it is low. First switch Second switch After being connected in series, it is then connected in parallel to the output terminal of the input circuit. (Based on the previous text...) Figure 2 An embodiment of the input circuit, namely the first switch Second switch After being connected in series, it is then connected in parallel to the capacitor. The two ends.

[0034] (3) Switch drive circuit.

[0035] The switch driver circuit is responsible for driving / controlling the operating state of the power switch circuit. Specifically, the switch driver circuit generates two inversely complementary PWM drive signals, where the first drive signal controls the first switch. The on / off state, the second drive signal controls the second switch The on / off state.

[0036] Since the first drive signal and the second drive signal are anti-complementary, that is, when the first drive signal is high, the second drive signal is low, and vice versa. Thus, the first switch... When the circuit is turned on, the second switch Turn off, or vice versa, the first switch. When turned off, the second switch Conduction.

[0037] In one alternative implementation, the switch drive circuit uses a dead-time generation circuit to generate a first drive signal and a second drive signal.

[0038] See appendix Figure 2 The dead-time generation circuit includes an upper bridge arm and a lower bridge arm. The dead-time generation circuit directly transmits the incoming PWM signal through the upper bridge arm to a first RC delay circuit for delay processing, outputting a first drive signal. The dead-time generation circuit then inverts the same PWM signal through the lower bridge arm, delays it through a second RC delay circuit, and outputs a second drive signal. The PWM signal can be generated by an active crystal oscillator; that is, the dead-time generation circuit is connected to an active crystal oscillator, which provides the same PWM signal to both the upper and lower bridge arms of the dead-time generation circuit.

[0039] In one specific embodiment, such as Figure 2 As shown, the first RC delay circuit includes a resistor. ,capacitance ,diode and inverter Among them, resistance With inverter Series connection, diode Reverse parallel to resistor Two ends (i.e., the direction of the diode's conduction current is opposite to the direction of the resistor's current), capacitor Connecting resistors An RC delay circuit is formed.

[0040] Similarly, the second RC delay circuit includes resistors. ,capacitance ,diode and inverter .resistance With inverter Series connection, diode Reverse parallel to resistor Two ends, capacitor Connecting resistors An RC delay circuit is formed.

[0041] The RC delay circuit in the dead-time generation circuit and its connected inverter can insert a dead time into the two complementary PWM drive signals, enabling the first switch to... Second switch Achieve complementary conduction to ensure the first switch Second switch Normal operation.

[0042] (4) Resonant cavity circuit.

[0043] The resonant cavity circuit is the key to the DC circuit breaker drive power supply circuit. It replaces the traditional transformer and achieves electrical isolation between the high and low voltage sides through the resonant cavity.

[0044] Specifically, the resonant cavity circuit includes a first resonant branch and a second resonant branch. The first resonant branch is connected to the output terminal of the output circuit, specifically between the input circuit and the rectifier circuit; the second resonant branch is connected between the half-bridge circuit and the output filter circuit.

[0045] As an alternative implementation, the first resonant branch forms a full-bridge structure with the power switching circuit, while the second resonant branch forms a full-bridge structure with the rectifier circuit.

[0046] like Figure 2 As shown, the first resonant branch includes a capacitor. ,capacitance and inductor .capacitance and capacitor After being connected in series, it is connected in parallel to the output terminal of the input circuit, that is, in parallel with the power switching circuit. Inductor One end is connected to the capacitor and capacitor One end is connected to the rectifier circuit, and the other end is connected to the inductor. With capacitor or capacitor To form an LC resonator.

[0047] The second resonant branch includes a capacitor. ,capacitance and inductor .capacitance and capacitor After being connected in series, it is connected in parallel with the rectifier circuit, that is, in parallel with the output filter circuit. Inductor One end is connected to the capacitor and capacitor Between the two ends, the other end is connected to a half-bridge circuit. Inductor With capacitor or capacitor To form an LC resonator.

[0048] In the circuit structures of the first and second resonant branches described above, the capacitor... and capacitor With half-bridge circuit (including the first switch) Second switch This constitutes the entire bridge structure.

[0049] (5) Rectifier circuit.

[0050] The rectifier circuit is connected between the first resonant branch and the second resonant branch, so that the resonant cavity circuit, the power switch circuit, and the rectifier circuit can form a complete loop.

[0051] Specifically, such as Figure 2 As shown, in one alternative embodiment, the rectifier circuit includes diodes connected in series in the same direction. and diodes A series connection in the same direction means that the two diodes conduct in the same direction. Diode and diodes After being connected in series, with the capacitor connected in series and capacitor Parallel connection. Inductors Connected to diode and diodes Between. In the structure of this rectifier circuit, the diode and diodes With capacitor and capacitor It constitutes the entire bridge structure.

[0052] In other words, the first resonant branch of the resonant cavity circuit forms a full-bridge structure with the power switching circuit, and the rectifier circuit forms a full-bridge structure with the second resonant branch of the resonant cavity circuit; the first resonant branch is connected to the rectifier circuit, and the second resonant branch is connected to the power switching circuit. Thus, by using the anti-complementary first and second driving signals generated by the switch driving circuit to asynchronously control the on / off states of the first and second switches, multiple current loops for corresponding bridge arm combinations of the two full-bridge structures are achieved, resulting in a stable output of positive and negative voltages.

[0053] (6) Output filter circuit.

[0054] The output filter circuit is connected to the second resonant branch, obtains the output voltage from the second resonant branch, and generates positive and negative dual output voltages after rectification, which are then output to the load.

[0055] Specifically, such as Figure 2 As shown, in one alternative embodiment, the output filter circuit includes an inductor. ,capacitance and capacitor .capacitance and capacitor After being connected in series, with the capacitor connected in series and capacitor Parallel connection; inductor One end is connected to the capacitor and capacitor Between, the other end is connected to the capacitor. and capacitor Between. Its inductance. As an output filter inductor, the capacitor and capacitor These are the output filter capacitors used for the forward and reverse outputs, respectively. The capacitor... The two ends form a positive voltage output terminal, and the capacitor The two ends form a negative voltage output terminal, forming a positive and negative dual output to meet the positive and negative power supply requirements of the power switching device.

[0056] In summary, the DC circuit breaker drive power supply circuit based on the resonant cavity isolation method proposed in this application achieves isolation through the combined action of the resonant cavity and the common-mode inductor. Employing GaN switching devices enables high switching frequency, reducing device size and weight while increasing power density. Furthermore, the circuit structure is simple, capable of simultaneously outputting stable positive and negative voltage values, ensuring the reliability of the drive power supply for power switching devices in large power equipment such as DC circuit breakers and converters, and demonstrating promising application prospects.

[0057] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A DC circuit breaker drive power supply circuit based on a resonant cavity isolation method, characterized in that, include: The input circuit has a voltage source connected to its input terminal, and noise suppression is applied to the voltage source. A power switching circuit includes a half-bridge circuit composed of a first switch and a second switch, the half-bridge circuit being connected to the output terminal of the output circuit. The switch driving circuit generates two inversely complementary PWM driving signals, wherein the first driving signal controls the on / off state of the first switch, and the second driving signal controls the on / off state of the second switch. The resonant cavity circuit includes a first resonant branch and a second resonant branch, wherein the first resonant branch is connected to the output terminal of the output circuit, and the second resonant branch is connected between the half-bridge circuit and the output filter circuit. A rectifier circuit is connected between the first resonant branch and the second resonant branch; The output filter circuit is connected to the second resonant branch to generate positive and negative dual output voltages.

2. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 1, characterized in that, The input circuit includes a common-mode inductor. and capacitor The common-mode inductor The two input terminals are connected to the voltage source, and the two output terminals are connected to the capacitor. in parallel.

3. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 1, characterized in that, The switch driving circuit includes a dead-time generation circuit; the dead-time generation circuit includes an upper bridge arm and a lower bridge arm. The dead-time generation circuit passes the input PWM signal directly through the upper bridge arm to the first RC delay circuit for delay processing, and outputs the first driving signal; the dead-time generation circuit inverts the PWM signal through the lower bridge arm, and then delays it through the second RC delay circuit, and outputs the second driving signal.

4. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 3, characterized in that, The PWM signal is generated by an active crystal oscillator.

5. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 3 or 4, characterized in that, The first RC delay circuit includes a resistor ,capacitance ,diode and inverter The resistor With the inverter The diodes are connected in series. Connected in reverse parallel to the resistor At both ends, the capacitor Connect the resistor Form an RC delay circuit; The second RC delay circuit includes resistors ,capacitance ,diode and inverter The resistor With the inverter The diodes are connected in series. Connected in reverse parallel to the resistor At both ends, the capacitor Connect the resistor An RC delay circuit is formed.

6. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 1, characterized in that, The first resonant branch includes a capacitor. ,capacitance and inductor The capacitor and capacitor The inductor is connected in series and then in parallel to the output terminal of the input circuit. One end is connected to the capacitor and capacitor Between the two ends, the other end is connected to the rectifier circuit; The second resonant branch includes a capacitor. ,capacitance and inductor The capacitor and capacitor After being connected in series, it is connected in parallel with the rectifier circuit, and the inductor One end is connected to the capacitor and capacitor Between the two ends, the other end is connected to the half-bridge circuit; The capacitor and capacitor Together with the half-bridge circuit, they form a full-bridge structure.

7. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 1, characterized in that, Both the first switch and the second switch are MOSFET switching transistors. The first switch and the second switch are connected in series and then connected in parallel to the output terminal of the input circuit; the second resonant branch is connected between the first switch and the second switch.

8. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 7, characterized in that, The MOSFET switch is a GaN power device.

9. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 6, characterized in that, The rectifier circuit includes diodes connected in series in the same direction. and diodes The diode and diodes After being connected in series, with the capacitor connected in series and capacitor Parallel connection; the inductor Connected to the diode and diodes between; The diode and diodes With the capacitor and capacitor It constitutes the entire bridge structure.

10. The DC circuit breaker drive power supply circuit based on the resonant cavity isolation method as described in claim 6, characterized in that, The output filter circuit includes an inductor. ,capacitance and capacitor The capacitor and the capacitor After being connected in series, with the capacitor connected in series and capacitor Parallel connection; the inductor One end is connected to the capacitor and the capacitor Between, the other end is connected to the capacitor. and the capacitor Between; the capacitor The capacitor forms a positive voltage output terminal at its two ends. The two ends form a negative voltage output terminal.

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