Solid-state switch conduction detection system and method for planar coreless transformer isolation
The solid-state switch continuity detection system, isolated by a planar coreless transformer, utilizes a cross-coupled oscillation circuit and a rectifier filter circuit to detect the conduction status of the field-effect transistor. This solves the problem of insufficient voltage isolation capability in existing circuits and achieves efficient and accurate continuity detection and fault diagnosis.
Patent Information
- Application Number
- CN202511715599.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-03-03
AI Technical Summary
Existing continuity detection circuits have poor voltage isolation capabilities and cannot meet the application requirements under high voltage, high frequency and high power conditions.
A solid-state switch continuity detection system using planar coreless transformer isolation includes a planar coreless transformer, a cross-coupled oscillation circuit, and a rectifier and filter circuit. It detects the change in drain-source resistance of the field-effect transistor, uses the planar coreless transformer to transmit the continuity detection signal, and converts it into a stable DC voltage through the rectifier and filter circuit. Combined with a threshold circuit, the reliability of the detection circuit is improved.
It achieves high-voltage isolation level, small size, and low cost conduction detection, can quickly and accurately detect the switching state of MOSFETs, provides an effective fault diagnosis method, and improves the reliability of power electronic systems.
Smart Images
Figure CN121596091A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power electronics technology, and in particular to a planar coreless transformer-isolated solid-state switch continuity detection system and method. Background Technology
[0002] Coreless transformers, as a new type of isolation device, have advantages such as fast frequency response, high voltage withstand rating, small size, light weight, and easy integration. They can provide electrical isolation and signal transmission functions, making them an ideal solution to replace optocouplers. By using coreless transformers, the continuity detection circuit only requires a single power supply, reducing circuit size while improving circuit reliability and response speed.
[0003] With the increasing voltage and power of power distribution systems, traditional protection devices such as relays and electromechanical circuit breakers are no longer sufficient to meet the requirements of fault isolation and load switching under high voltage conditions due to their shortcomings in response speed and isolation capability. Intelligent solid-state switches (such as solid-state power controllers (SSPCs), solid-state relays (SSRs), and solid-state circuit breakers (SSBCs)) are gradually replacing traditional mechanical switches and are widely used in intelligent solid-state power distribution systems in automobiles, aviation, and aerospace due to their advantages of high voltage withstand capability, fast response, small size, and high reliability. The core components of these intelligent solid-state switches are semiconductor power devices such as MOSFETs and IGBTs. Effectively monitoring and protecting these power devices has become crucial for ensuring the stable operation of power systems. Accurately detecting the conduction state of intelligent solid-state switches is essential under high power and high frequency operating conditions. Traditional conduction detection circuits typically use optocouplers for isolation, but optocouplers have drawbacks such as low voltage withstand capability, easy aging, slow response speed, and temperature sensitivity, limiting their application in high-voltage, high-frequency, and high-power applications. Furthermore, optocouplers require power supplies for both input and output, resulting in large circuit size and high energy consumption, making it difficult to meet the miniaturization and efficiency requirements of modern power systems.
[0004] To address these issues, researchers have proposed various continuity detection schemes. For example, microprocessors such as MCUs, DSPs, and FPGAs are used for remote control, status monitoring, and fault diagnosis of intelligent solid-state switches. Furthermore, researchers have added short-circuit protection, desaturation protection, overcurrent protection, and overvoltage protection to intelligent solid-state switches to ensure the stable operation of the power distribution system. However, these schemes still have certain limitations in terms of high-voltage isolation, response speed, and integration. Summary of the Invention
[0005] The purpose of this invention is to provide a solid-state switch continuity detection system and method with planar coreless transformer isolation, which aims to solve the problem of poor voltage isolation capability of existing continuity detection circuits.
[0006] To achieve the above objectives, in a first aspect, the present invention provides a solid-state switch continuity detection system with planar coreless transformer isolation, comprising a solid-state switch continuity detection circuit and a threshold circuit, wherein the solid-state switch continuity detection circuit comprises a planar coreless transformer, a cross-coupled oscillation circuit and a rectifier filter circuit;
[0007] The planar coreless transformer is used to transmit continuity detection signals;
[0008] The cross-coupled oscillation circuit is used to detect the on / off state of the field-effect transistor and generate a stable sine wave.
[0009] The rectifier and filter circuit is used to convert AC voltage signals into stable DC voltage.
[0010] The threshold circuit is used to improve the reliability of the detection circuit.
[0011] The planar coreless transformer includes a primary coil and a secondary coil, which are stacked and completely overlap in the vertical direction.
[0012] The cross-coupled oscillation circuit includes transistor M1, transistor M2, resonant capacitor C1, and resonant inductor L1.
[0013] The rectifier and filter circuit includes a rectifier diode D1, an output filter capacitor C2, and a load RL.
[0014] Secondly, a method for detecting the continuity of a solid-state switch with planar coreless transformer isolation, used in the solid-state switch continuity detection system with planar coreless transformer isolation described in the first aspect, includes the following steps:
[0015] When the field-effect transistor is turned on, the cross-coupled oscillation circuit starts to work, generates a stable sine wave, and transmits the turn-on signal to the secondary coil through the planar coreless transformer.
[0016] After the secondary coil receives the conduction signal, it obtains a stable DC voltage through the rectifier and filter circuit, and the output of the conduction detection circuit is at a high level.
[0017] When the field-effect transistor is turned off, the cross-coupled oscillation circuit is in a static state, and the output of the conduction detection circuit is low.
[0018] The microcontroller determines the on / off state of the field-effect transistor by detecting the level of the output terminal of the continuity detection circuit.
[0019] This invention discloses a solid-state switch continuity detection system with planar coreless transformer isolation, comprising a solid-state switch continuity detection circuit and a threshold circuit. The solid-state switch continuity detection circuit includes a planar coreless transformer, a cross-coupled oscillation circuit, and a rectifier-filter circuit. The planar coreless transformer transmits the continuity detection signal; the cross-coupled oscillation circuit detects the on / off state of the field-effect transistor (FET) and generates a stable sine wave; the rectifier-filter circuit converts the AC voltage signal into a stable DC voltage. The threshold circuit improves the reliability of the detection circuit. This invention can accurately and quickly detect the switching state of the FET, and has advantages such as high voltage isolation level, small size, and low cost. It can provide an effective fault diagnosis method for intelligent solid-state switches in practical applications. In future research, it can be combined with short-circuit protection circuits and overvoltage / overcurrent protection circuits to design protection circuits for solid-state switches, improving the reliability of power electronic systems. This solves the problem of poor voltage isolation capability in existing continuity detection circuits. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of a solid-state switch continuity detection system with planar coreless transformer isolation provided by the present invention.
[0022] Figure 2 It is a coreless transformer model structure.
[0023] Figure 3 (a) is a graphic symbol diagram of an N-channel field-effect transistor; (b) is an equivalent circuit diagram of the drain-source resistance of a field-effect transistor.
[0024] Figure 4 It is the waveform for detecting the conduction of a field-effect transistor.
[0025] Figure 5 A continuity detection circuit based on coreless transformer isolation.
[0026] Figure 6 This is a flowchart of a solid-state switch continuity detection method for planar coreless transformer isolation provided by the present invention.
[0027] In the diagram: 1-Planar coreless transformer, 2-Solid-state switch conduction detection circuit, 3-Threshold circuit, 4-Cross-coupled oscillation circuit, 5-Rectifier and filter circuit, 6-Primary coil, 7-Secondary coil. Detailed Implementation
[0028] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0029] Please see Figures 1 to 5 In a first aspect, the present invention provides a solid-state switch conduction detection system isolated by a planar coreless transformer 1, including a solid-state switch conduction detection circuit 2 and a threshold circuit 3. The solid-state switch conduction detection circuit 2 includes a planar coreless transformer 1, a cross-coupled oscillation circuit 4 and a rectifier filter circuit 5.
[0030] The planar coreless transformer 1 is used to transmit continuity detection signals;
[0031] The cross-coupled oscillation circuit 4 is used to detect the on / off state of the field-effect transistor and generate a stable sine wave.
[0032] The rectifier and filter circuit 5 is used to convert AC voltage signals into stable DC voltage.
[0033] The threshold circuit 3 is used to improve the reliability of the detection circuit.
[0034] Furthermore, the planar coreless transformer 1 includes a primary coil 6 and a secondary coil 7, wherein the primary coil 6 and the secondary coil 7 are stacked and completely overlap in the vertical direction.
[0035] Furthermore, the cross-coupled oscillation circuit 4 includes transistor M1, transistor M2, resonant capacitor C1, and resonant inductor L1.
[0036] Furthermore, the rectifier-filter circuit 5 includes a rectifier diode D1, an output filter capacitor C2, and a load RL.
[0037] In this embodiment, the planar coreless transformer 1 has a turns ratio of 1:1. The transformer has a planar spiral structure, and the primary coil 6 and the secondary coil 7 are stacked. To reduce the circuit size, the primary coil 6 and the secondary coil 7 are located on different layers of the planar PCB and are completely overlapped in the vertical direction. The planar coreless transformer 1 is used to transmit the conduction detection signal; the cross-coupled oscillation circuit 4 is used to detect the on / off state of the field-effect transistor and generate a stable sine wave; the rectifier and filter circuit 5 is used to convert the AC voltage signal into a stable DC voltage. The threshold circuit 3 is used to improve the reliability of the detection circuit. By using the cross-coupled oscillation circuit 4 to detect the change in the drain-source resistance of the field-effect transistor, and transmitting the conduction signal of the field-effect transistor through the planar coreless transformer 1, the signal is output through the rectifier and filter circuit 5 and then fed back to the MCU, ultimately enabling the MCU to obtain the on / off signal of the field-effect transistor. This invention can detect the on / off state of the field-effect transistor in a timely and effective manner and can quickly feed back the on / off signal to the MCU. This invention improves the reliability and safety of electrical systems by designing them into multiple miniaturized, functionally specialized modules. Utilizing advanced microelectronics and computer control technologies, it enables intelligent management and control of the electrical system. This invention can accurately and quickly detect the switching state of MOSFETs, offering advantages such as high voltage isolation, small size, and low cost. It provides an effective fault diagnosis method for intelligent solid-state switches in practical applications. Future research can integrate short-circuit protection circuits and overvoltage / overcurrent protection circuits into the design of protection circuits for solid-state switches, further improving the reliability of power electronic systems. This solves the problem of poor voltage isolation capability in existing continuity detection circuits.
[0038] Example:
[0039] Based on the dynamic characteristics of the drain-source resistance of the field-effect transistor, such as Figure 3 As shown. With a fixed drain-source voltage, the drain-source resistance (Rds) changes with the gate-source voltage (Rds). Significant changes occur due to variations in the gate-source voltage. Taking an N-type field-effect transistor as an example, when the gate-source voltage... When the PN junction between the drain and source is reverse biased, the device remains in the off state. At this time, the drain-source resistance approaches infinity. The load circuit is in an open circuit state; when the gate-source voltage is greater than the threshold voltage, i.e. When the field-effect transistor is in the on state, the drain-source resistance exhibits low impedance characteristics. Ideally, under these conditions... The load circuit forms a closed loop. Therefore, the switching state of the field-effect transistor can be obtained by detecting the state of the drain-source resistance.
[0040] Figure 1Based on the dynamic characteristics of the drain-source resistance of a field-effect transistor (FET), a solid-state switch conduction detection circuit scheme 2 is designed. When the gate control signal of the FET is low, the FET is in the off state, and the drain-source resistance is high. The conduction detection circuit does not generate an output signal, and the output terminal (STA) of the threshold circuit 3 is low. When the gate control signal is high, the FET is turned on and operates in saturation. The drain-source resistance is low, and the conduction detection circuit generates a high-level signal. This level is higher than the threshold voltage of the threshold circuit 3, and the threshold circuit 3 outputs a high level. The MCU determines the on / off state of the FET by reading the level of the output signal (STA) of the threshold circuit 3.
[0041] Figure 1 The planar coreless transformer 1 is used to transmit the conduction detection signal. According to Ampere's law and Faraday's law of electromagnetic induction, when an alternating current passes through the primary coil 6, an alternating magnetic field is generated. The secondary coil 7 is coupled with this magnetic field and generates an induced electromotive force under the action of the alternating magnetic field, thereby outputting an AC voltage.
[0042] Figure 1 The cross-coupled oscillator circuit 4 is used to detect the on / off state of the field-effect transistor (FET) and generate a stable sine wave. When the FET is on, the cross-coupled oscillator circuit 4 starts working, generating a stable sine wave and transmitting the on / off signal to the secondary coil 7 through the planar coreless transformer 1. After receiving the on / off signal, the secondary coil 7 obtains a stable DC voltage through the rectifier and filter circuit 5, and the output of the on / off detection circuit is high. When the FET is off, the cross-coupled oscillator circuit 4 is in a static state, and the output of the on / off detection circuit is low. The output signal of the rectifier and filter circuit 5 passes through the threshold circuit 3, transmitting the on / off detection signal to the microcontroller system, which can then determine the on / off state of the FET.
[0043] Furthermore, this invention verifies the correctness of the conduction detection circuit design by designing a PBC circuit sample. The experimental results of field-effect transistor conduction detection using the circuit of this invention are as follows: Figure 4 As shown. The specific experimental procedure is as follows: A gate isolation driver is used to drive the MOSFET, and the on / off state of the MOSFET is detected using the conduction detection circuit of this invention. An oscilloscope probe is connected to the drain and source of the MOSFET and the output terminal of the conduction detection circuit, respectively. The oscilloscope is set to rising edge trigger mode to test the time required for the conduction detection circuit to output a detection signal after the MOSFET is turned on.
[0044] Depend on Figure 3 As can be seen, the conduction detection circuit outputs a stable DC voltage 390ns after the MOSFET is turned on. The main parameters of the design in this application are compared with those of the commercially available optocoupler TLP293, as shown in Table 1.
[0045] Table 1 Comparison of Key Performance Parameters
[0046]
[0047] As shown in Table 1, compared with the optocoupler TLP293, the overall power consumption of the conduction detection circuit scheme proposed in this application is as low as 51mV, and the signal transmission delay is reduced to 390ns and the isolation voltage is >10KV.
[0048] The present invention has the following beneficial effects:
[0049] This invention can accurately and quickly detect the switching state of a field-effect transistor, and has the advantages of high voltage isolation level, small size and low cost.
[0050] This provides an effective fault diagnosis method for intelligent solid-state switches in practical applications. Future research could combine short-circuit protection circuits and overvoltage / overcurrent protection circuits in the design of solid-state switch protection circuits to improve the reliability of power electronic systems.
[0051] Please see Figure 6 Secondly, a method for detecting the continuity of a solid-state switch isolated by a planar coreless transformer 1, used in the solid-state switch continuity detection system isolated by the planar coreless transformer 1 described in the first aspect, includes the following steps:
[0052] When the field-effect transistor S1 is turned on, the cross-coupled oscillation circuit 4 starts to work, generates a stable sine wave, and transmits the turn-on signal to the secondary coil 7 through the planar coreless transformer 1.
[0053] Specifically, when the field-effect transistor is turned on, the cross-coupled oscillation circuit 4 starts to work, forming a continuous and stable sine wave, and transmitting the turn-on signal to the secondary coil 7 through the planar coreless transformer 1.
[0054] After the secondary coil 7 of S2 receives the conduction signal, it obtains a stable DC voltage through the rectifier and filter circuit 5, and the output of the conduction detection circuit is high level.
[0055] Specifically, after the secondary coil 7 receives the conduction signal, it obtains a stable DC voltage after passing through the rectifier and filter circuit 5, that is, the output of the conduction detection circuit is at a high level.
[0056] When the field-effect transistor S3 is turned off, the cross-coupled oscillation circuit 4 is in a static state, and the output of the conduction detection circuit is low.
[0057] Specifically, when the field-effect transistor is in the off state, the cross-coupled oscillation circuit 4 is in a static state, and the output of the conduction detection circuit is low.
[0058] The S4 microcontroller determines the on / off state of the field-effect transistor by detecting the level of the output terminal of the continuity detection circuit.
[0059] Specifically, the microcontroller unit (MCU) determines the on / off state of the field-effect transistor by detecting the level state at the output of the conduction detection circuit. The conduction state of the solid-state switch is determined by detecting the dynamic change in the drain-source resistance of the field-effect transistor.
[0060] The above-disclosed embodiments are merely preferred embodiments of the solid-state switch continuity detection system and method with planar coreless transformer isolation according to the present invention. Of course, they should not be construed as limiting the scope of the present invention. Those skilled in the art can understand that implementing all or part of the above embodiments and making equivalent changes in accordance with the claims of the present invention still fall within the scope of the invention.
Claims
1. A solid-state switch continuity detection system with planar coreless transformer isolation, characterized in that, It includes a solid-state switch conduction detection circuit and a threshold circuit. The solid-state switch conduction detection circuit includes a planar coreless transformer, a cross-coupled oscillation circuit, and a rectifier and filter circuit. The planar coreless transformer is used to transmit continuity detection signals; The cross-coupled oscillation circuit is used to detect the on / off state of the field-effect transistor and generate a stable sine wave. The rectifier and filter circuit is used to convert AC voltage signals into stable DC voltage. The threshold circuit is used to improve the reliability of the detection circuit.
2. The solid-state switch continuity detection system with planar coreless transformer isolation as described in claim 1, characterized in that, The planar coreless transformer includes a primary coil and a secondary coil, which are stacked and completely overlap in the vertical direction.
3. The solid-state switch continuity detection system with planar coreless transformer isolation as described in claim 1, characterized in that, The cross-coupled oscillation circuit includes transistor M1, transistor M2, resonant capacitor C1, and resonant inductor L1.
4. The solid-state switch continuity detection system with planar coreless transformer isolation as described in claim 1, characterized in that, The rectifier and filter circuit includes a rectifier diode D1, an output filter capacitor C2, and a load RL.
5. A method for detecting the continuity of a solid-state switch with planar coreless transformer isolation, the solid-state switch continuity detection system with planar coreless transformer isolation as described in any one of claims 1-4, characterized in that, Includes the following steps: When the field-effect transistor is turned on, the cross-coupled oscillation circuit starts to work, generates a stable sine wave, and transmits the turn-on signal to the secondary coil through the planar coreless transformer. After the secondary coil receives the conduction signal, it obtains a stable DC voltage through the rectifier and filter circuit, and the output of the conduction detection circuit is at a high level. When the field-effect transistor is turned off, the cross-coupled oscillation circuit is in a static state, and the output of the conduction detection circuit is low. The microcontroller determines the on / off state of the field-effect transistor by detecting the level of the output terminal of the continuity detection circuit.