Positive and negative voltage output circuit based on coreless transformer isolation

Abstract

The invention relates to the technical field of electronic power, in particular to a positive and negative voltage output circuit based on coreless transformer isolation, which comprises a cross-coupled oscillation circuit, a coreless transformer and a rectification filter circuit, and is characterized in that the cross-coupled oscillation circuit generates sine wave oscillation, and energy is transmitted to a secondary coil through a primary coil of the coreless transformer. The secondary coil adopts a center tap structure, the rectification filter circuit receives signals transmitted by the secondary coil, and stable positive and negative voltage output is realized through rectification and filtering processing. High-efficiency energy transmission is achieved through the coreless transformer, the voltage isolation capacity is improved, electromagnetic interference is reduced, and the coreless transformer has the advantages of being compact in structure, low in cost, high in power density and the like and is suitable for solid-state switch driving, high-frequency power conversion and other electronic power systems.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic power, and particularly to a positive and negative voltage output circuit based on coreless transformer isolation. Background Art

[0002] In modern power electronic systems, solid-state switching devices (such as IGBTs, MOSFETs, SiC MOSFETs, etc.) have become the core components for high-voltage and high-power applications. These devices are widely used in equipment such as inverters, DC-DC converters, power amplifiers, and high-frequency converters. Their performance and reliability directly affect the operating efficiency of the entire system. To ensure the normal operation of solid-state switches, a stable and isolated drive power supply is required to meet the drive requirements in different operating modes, while ensuring the safety and anti-interference ability of the system. In high-voltage power electronic systems, isolation drive technology is crucial. Its core function is to achieve electrical isolation between the high-voltage side and the low-voltage side to prevent high-voltage crosstalk, improve the electromagnetic compatibility (EMC) of the system, and ensure the stable and reliable operation of the system.

[0003] Currently, isolation drive power supplies mainly adopt optocoupler isolation and traditional iron-core transformer isolation technologies. However, traditional isolation methods still have many deficiencies. For example, optocouplers have aging problems, and traditional iron-core transformers have problems such as large volume and difficulty in integration. These problems limit the development of power electronic systems towards higher power density and higher efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a positive and negative voltage output circuit based on coreless transformer isolation, aiming to improve the voltage isolation ability of the electronic circuit, provide two voltage outputs of positive voltage and negative voltage for the circuit, and at the same time solve the problem of difficulty in integrating the circuit.

[0005] To achieve the above object, the present invention provides a positive and negative voltage output circuit based on coreless transformer isolation, which is composed of a cross-coupled oscillation circuit, a planar coreless transformer, and a rectifier filter circuit connected in sequence. The cross-coupled oscillation circuit uses a DC power supply input, and the planar coreless transformer and the rectifier filter circuit constitute the output circuit;

[0006] The cross-coupled oscillation circuit includes transistors M1 and M2, resonant capacitor C1, and resonant inductor L1. The gates and sources of transistors M1 and M2 are cross-connected, and two groups of resonant inductors L1 are connected in series and are simultaneously connected in parallel with resonant capacitor C1;

[0007] The rectifier filter circuit includes two outputs of positive voltage and negative voltage, and the rectifier filter circuit is composed of a center-tapped transformer, rectifier diodes D1, D2, and filter capacitors C2, C3.

[0008] Among them, the planar coreless transformer includes a primary coil and two secondary coils. The turns ratio of the transformer is 1:1:1. The transformer is of a planar spiral structure, and the primary coil and the secondary coils adopt a laminated structure and completely coincide in the vertical direction.

[0009] Among them, the secondary coils are symmetrically wound, and a center tap is led out between the two windings to provide a symmetric AC voltage signal.

[0010] Among them, the number of the rectifying and filtering circuits is the same as the number of the secondary coils of the planar coreless transformer.

[0011] The present invention provides a positive and negative voltage output circuit based on coreless transformer isolation, which is composed of a cross-coupled oscillation circuit, a coreless transformer, and a rectifying and filtering circuit. Among them, the cross-coupled oscillation circuit generates a sine wave oscillation, and the energy is transmitted to the secondary coil through the primary coil of the coreless transformer. The secondary coil adopts a center tap structure, and the rectifying and filtering circuit receives the signal transmitted by the secondary coil and performs rectifying and filtering processing to achieve stable positive and negative voltage output. The present invention realizes efficient energy transmission through the coreless transformer, improves the voltage isolation ability, reduces electromagnetic interference, and has the advantages of compact structure, low cost, high power density, etc., and is applicable to solid-state switch drive, high-frequency power conversion, and other electronic power systems. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0013] Figure 1 It is a schematic diagram of the principle structure of a positive and negative voltage output circuit based on coreless transformer isolation of the present invention.

[0014] Figure 2 It is a schematic diagram of the model structure of the planar coreless transformer of the present invention.

[0015] Figure 3 It is a schematic diagram of the connection structure of the cross-coupled oscillation circuit of the present invention.

[0016] Figure 4 It is a schematic diagram of the connection structure of the positive and negative voltage rectifying output circuit of the rectifying and filtering circuit of the present invention. Detailed Embodiments

[0017] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0018] Please refer to Figures 1 to 3 , the present invention provides a positive and negative voltage output circuit based on coreless transformer isolation, which is composed of a cross-coupled oscillation circuit, a planar coreless transformer, and a rectifier filter circuit connected in sequence. The cross-coupled oscillation circuit uses a DC power supply input, and the planar coreless transformer and the rectifier filter circuit constitute the output circuit;

[0019] The cross-coupled oscillation circuit includes transistors M1 and M2, resonance capacitor C1, and resonance inductor L1, where transistors M1 and M2 are cross-connected, and two groups of resonance inductors L1 are connected in series and are simultaneously connected in parallel with resonance capacitor C1.

[0020] The planar coreless transformer includes a primary coil and two secondary coils. The turns ratio of the transformer is 1:1:1. The transformer is of a planar spiral structure. The primary coil and the secondary coils adopt a stacked structure. The primary coil and the secondary coils are respectively in different layers of the planar PCB and completely coincide in the vertical direction.

[0021] The secondary coils are symmetrically wound, and a center tap is led out between the two windings to provide a symmetric AC voltage signal.

[0022] The rectifier filter circuit includes rectifier diodes D1, D2, output filter capacitors C2, C3, and load RL. The number of the rectifier filter circuits is the same as the number of the secondary coils of the planar coreless transformer.

[0023] In this embodiment, the cross-coupled oscillation circuit generates a stable sine wave signal. This sine wave signal passes through the coreless transformer, and the energy is transmitted from the primary coil to the secondary coil through electromagnetic coupling, thereby realizing the energy transmission. The rectifier filter circuit is connected to the secondary of the coreless transformer. Its function is to receive the signal transmitted by the primary coil and filter the received signal; the secondary coils of the coreless transformer are connected together, and a center tap is led out between the coils to become a center-tapped transformer. The output circuit uses the center tap as the reference ground, and rectifier filter circuits are respectively added at the back end of the transformer to convert the AC voltage signal into a stable positive and negative DC voltage.

[0024] The working principle of the circuit is as follows: First, the DC power supply supplies power to the cross-coupled oscillation circuit. After the cross-coupled oscillation circuit meets the amplitude condition and phase condition, it generates a stable sine wave signal. This signal is coupled to the secondary coil through the primary coil of the coreless transformer. After passing through the rectifier and filter circuit, positive and negative voltages are output, and finally a stable DC voltage can be provided for the system circuit.

[0025] Specifically, the working voltage of the cross-coupled oscillation circuit is 5V. Then, through the self-excited oscillation of the cross-coupled oscillation circuit, a high-frequency alternating magnetic field is generated in the primary coil of the coreless transformer. This alternating magnetic field acts on the secondary coil of the coreless transformer through electromagnetic coupling, and a corresponding high-frequency alternating voltage is induced in the secondary coil. Since the secondary coil of the coreless transformer adopts a center-tapped structure, the induced AC signal can use the center tap as the reference ground to obtain two symmetrical AC signals respectively.

[0026] These two AC signals enter the rectifier and filter circuit, are rectified by the rectifier diode to convert the AC signal into a DC signal, and then further smoothed by capacitor filtering to finally obtain a stable positive and negative voltage output.

[0027] Compared with the traditional iron-core transformer isolation scheme, the planar coreless transformer structure adopted in the present invention eliminates the magnetic saturation problem and greatly reduces the influence of parasitic parameters, enabling the system to operate efficiently at high frequencies. In addition, through the self-excited oscillation characteristic of the cross-coupled oscillation circuit, high-efficiency conversion can be achieved without an external drive signal, reducing the dependence on the control circuit and simplifying the system design.

[0028] In summary, the present invention has the following beneficial effects:

[0029] The positive and negative voltage output circuit based on coreless transformer isolation proposed by the present invention can provide stable positive and negative DC output voltages. This circuit has the advantages of high voltage isolation level, small volume, low cost, etc. Using the coreless transformer structure eliminates the magnetic saturation problem of the traditional iron-core transformer, and at the same time reduces the influence of leakage inductance and parasitic capacitance, enabling the system to maintain high efficiency and stability under high-frequency conditions. In addition, the circuit topology of the present invention is simple, without an additional complex control circuit, which can effectively reduce the system design and manufacturing costs and improve the overall reliability. The proposal of the present invention provides a new solution for the design of high-efficiency isolated drive power supplies.

[0030] The above-disclosed are only one or more preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited by this. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A positive and negative voltage output circuit based on coreless transformer isolation, characterized in that: It is composed of a cross-coupled oscillator circuit, a planar coreless transformer and a rectifier filter circuit connected in sequence, wherein the cross-coupled oscillator circuit uses a DC power supply input, and the planar coreless transformer and the rectifier filter circuit constitute an output circuit; The cross-coupled oscillator circuit includes transistors M1 and M2, a resonant capacitor C1 and a resonant inductor L1, wherein the gates and sources of the transistors M1 and M2 are cross-connected, and two sets of resonant inductors L1 are connected in series and in parallel with the resonant capacitor C1; The rectification and filtering circuit includes two outputs of positive voltage and negative voltage, and the rectification and filtering circuit is composed of a center-tapped transformer, rectification diodes D1, D2 and filtering capacitors C2, C3.

2. The positive and negative voltage output circuit based on coreless transformer isolation as claimed in claim 1, characterized in that: The planar coreless transformer comprises a primary coil and two secondary coils, the transformation ratio of the transformer is 1:1:1, the transformer is a planar spiral structure, the primary coil and the secondary coil adopt a stacked structure and completely overlap in the vertical direction.

3. The positive and negative voltage output circuit based on coreless transformer isolation as claimed in claim 2, characterized in that: The secondary coil is symmetrically wound, and a center tap is drawn between the two windings to provide a symmetrical AC voltage signal.

4. The positive and negative voltage output circuit based on coreless transformer isolation as claimed in claim 3, characterized in that: The number of the rectifying and filtering circuits is the same as the number of the secondary coils of the planar coreless transformer.

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