Magnetorheological fluid heating system based on high-frequency ripple generation circuit

Abstract

The invention provides a magnetorheological fluid heating system based on a high-frequency ripple generation circuit, and relates to the technical field of application of high-frequency electronic circuits and magnetorheological intelligent materials, the magnetorheological fluid heating system comprises a power supply and control module, a high-frequency ripple generation module, a high-frequency coupling module, a magnetorheological fluid heating module and a temperature monitoring feedback module; the power supply and control module is in communication connection with the input end of the high-frequency ripple generation module, the output end of the high-frequency ripple generation module is in communication connection with the input end of the high-frequency coupling module, the output end of the high-frequency coupling module is in communication connection with the magnetorheological fluid heating module, and the magnetorheological fluid heating module is in communication connection with the temperature monitoring feedback module. The system is efficient and energy-saving, low-temperature starting is fast, the energy conversion efficiency is greatly improved, and the energy-saving effect is better; the problem of low-temperature failure of the magneto-rheological device is effectively solved, high integration is achieved, space and cost are saved, material cost and assembly complexity are reduced, and therefore the overall failure rate of the system is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of high-frequency electronic circuits and magnetorheological smart material application technology, and more specifically, to a magnetorheological fluid heating system based on a high-frequency ripple generation circuit. Background Technology

[0002] Magnetorheological fluids, as intelligent and controllable fluids, can have their rheological properties rapidly adjusted by an external magnetic field, and are widely used in vehicle suspension and braking systems. However, magnetorheological fluids have a low-temperature performance bottleneck: in environments below -5°C, their viscosity increases sharply by 3 to 5 times, resulting in a damper response delay of ≥50ms, which seriously affects vehicle handling stability; at the same time, the magnetic response sensitivity of magnetorheological fluids decreases at low temperatures, further reducing the system control accuracy.

[0003] Existing magnetorheological fluid (MRF) heating solutions suffer from three main drawbacks: First, the use of resistance wire heating results in poor heating uniformity (temperature difference ≥15℃) and requires additional installation space, increasing equipment size by more than 15%. Second, the high-frequency heating circuit employs a single-switch hard topology, leading to high switching losses and strong electromagnetic interference that can affect other onboard electronic devices. Third, the heating and magnetic control circuits are designed independently, resulting in high system complexity, increased failure rate, and an inability to meet the integration and lightweight requirements of automotive applications. Existing high-frequency ripple generation circuits largely rely on hard-switching topologies, exhibiting problems such as high switching transistor stress, unstable ripple frequency, and weak noise suppression, making them unsuitable for the "high frequency, high efficiency, and low interference" requirements of MRF heating. Therefore, there is an urgent need for an integrated, high-efficiency, automotive-grade high-frequency ripple generation and heating solution to address the shortcomings of existing technologies. Summary of the Invention

[0004] The present invention aims to solve the problems of poor heating uniformity, high switching losses, and high system complexity of existing magnetorheological fluids.

[0005] To address the aforementioned problems, this invention provides a magnetorheological fluid heating system based on a high-frequency ripple generation circuit, comprising a power supply and control module, a high-frequency ripple generation module, a high-frequency coupling module, a magnetorheological fluid heating module, and a temperature monitoring and feedback module; the power supply and control module and the input terminal of the high-frequency ripple generation module are communicatively connected, the output terminal of the high-frequency ripple generation module is communicatively connected to the input terminal of the high-frequency coupling module, the output terminal of the high-frequency coupling module is communicatively connected to the magnetorheological fluid heating module, and the magnetorheological fluid heating module is communicatively connected to the temperature monitoring and feedback module; The power supply and control module's power supply terminal is connected to the vehicle / industrial power supply; the control terminal of the power supply and control module is connected to the MCU; the vehicle / industrial power supply is connected to the DC-DC conversion module; the MCU is connected to the frequency / amplitude adjustment and temperature feedback judgment module, and the frequency / amplitude adjustment and temperature feedback judgment module is communicatively connected to the temperature monitoring feedback module.

[0006] The magnetorheological fluid heating system based on a high-frequency ripple generation circuit provided by this invention has, but is not limited to, the following beneficial effects compared to the prior art: The power supply and control module of this invention is responsible for the stable operation and intelligent control of the entire system. It converts the 12V power supply from the vehicle / industrial system into different voltage levels required by each unit. The high-frequency ripple generation module is responsible for efficiently converting DC power into high-frequency AC power. The high-frequency coupling module is responsible for safely and efficiently transmitting high-frequency energy. The magnetorheological fluid heating module utilizes a single excitation coil. When a high-frequency ripple current passes through, the high-frequency alternating magnetic field generated by the coil directly generates heat in the magnetic particles (hysteresis loss) and adjacent magnetic core (eddy current loss) of the magnetorheological fluid, thereby efficiently and uniformly heating the fluid. The temperature monitoring and feedback module achieves a closed-loop system for precise temperature control.

[0007] This invention is highly efficient and energy-saving, with rapid low-temperature start-up, significantly improved energy conversion efficiency, and better energy-saving effect; it effectively solves the problem of low-temperature failure of magnetorheological devices.

[0008] This invention is highly integrated, saving space and cost. The heating and magnetic control functions reuse the same excitation coil and magnetic circuit structure, eliminating the need for a separate heater, which greatly reduces the size of the equipment, lowers material costs and assembly complexity, and thus greatly reduces the overall system failure rate.

[0009] Furthermore, the power supply and control module includes a DC power supply unit and a drive control unit; the DC power supply unit includes an on-board power supply, and the drive control unit includes a power amplifier, a switching unit, an STM32 microcontroller, a thermocouple conditioning chip, and an output module; the on-board power supply is connected to the 12V DC power supply module, the boost module, and the buck module via fuses respectively. The 12V DC power supply module is electrically connected to the power amplifier through the first filter circuit; the boost module is electrically connected to the switching unit through the second filter circuit; and the buck module is electrically connected to the STM32 microcontroller and the thermocouple conditioning chip through the third filter circuit. The switching unit is electrically connected to the output module; The output of the STM32 microcontroller is electrically connected to the power amplifier through a current-limiting resistor and an AC coupling capacitor; the thermocouple conditioning chip is communicatively connected to the input of the STM32 microcontroller through a filter capacitor. The source sampling resistor of the switching power supply is connected to the input of the STM32 microcontroller via an automotive-grade operational amplifier; the magnetizing coil sampling resistor is connected to the input of the STM32 microcontroller via another automotive-grade operational amplifier.

[0010] Furthermore, the STM32 microcontroller includes a TIM1 timer and a 12-bit ADC module; the thermocouple conditioning chip is communicatively connected to the 12-bit ADC module of the STM32 microcontroller through a filter capacitor.

[0011] Furthermore, the magnetorheological fluid heating module includes a DC power supply E1, a fuse F2, a MOSFET Q1, a MOSFET Q2, a capacitor C4, an inductor H, a transformer F3, a capacitor C6, a fuse F1, a DC power supply E2, and an excitation coil L1. The positive terminal of the DC power supply E1 is connected to one end of the fuse F2, the other end of the fuse F2 is connected to the drain of the MOSFET Q1, the source of the MOSFET Q1 is connected to the drain of the MOSFET Q2, and the source of the MOSFET Q2 is connected to the negative terminal of the DC power supply E1. The gate of MOSFET Q1 is connected to an input signal; The gate of MOSFET Q2 is connected to another input signal; The drain of MOSFET Q2 is connected to one end of inductor H, and the other end of inductor H is connected to one end of the high-voltage side of transformer F3; the source of MOSFET Q2 is connected to one end of capacitor C4, and the other end of capacitor C4 is connected to the other end of the high-voltage side of transformer F3. One end of the low-voltage side of transformer F3 is connected to one end of capacitor C6, the other end of capacitor C6 is connected to one end of fuse F1, and the other end of fuse F1 is connected to the positive terminal of DC power supply E2. The negative terminal of DC power supply E2 is connected to the other end of the low-voltage side of transformer F3; One end of the excitation coil L1 is connected to the connecting wire between capacitor C6 and fuse F1, and the other end of the excitation coil L1 is connected to the negative terminal of DC power supply E2.

[0012] Furthermore, a capacitor C2 is connected in parallel between the drain and source of the MOS transistor Q1.

[0013] Furthermore, a capacitor C3 is connected in parallel between the drain and source of the MOS transistor Q2.

[0014] Furthermore, a capacitor C5 is connected in parallel across the high-voltage side of the transformer F3.

[0015] Furthermore, the DC power supply E1 is a 24V DC power supply.

[0016] Furthermore, the DC power supply E2 is a 12V DC power supply.

[0017] Furthermore, the switching unit is a GaN device, model EPC2045. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the framework of a magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the power supply and control module in a magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to an embodiment of the present invention. Figure 3 This is a circuit diagram of the magnetorheological fluid heating module of the magnetorheological fluid heating system based on a high-frequency ripple generation circuit, according to an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings showing multiple embodiments according to this application. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," etc., in the description, claims, and accompanying drawings of this application are open-ended terms. Therefore, "comprising," "including," or "having" refers to, for example, a method or apparatus having one or more steps or elements, but is not limited to having only these one or more elements. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] It should be emphasized that when the term "comprising / including" is used in this specification, it is used to explicitly indicate the presence of the stated feature, integer, step, or component, but does not exclude the presence or addition of one or more other features, integers, steps, parts, or groups of features, integers, steps, or parts.

[0024] In this application, 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. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0025] This invention relates to the field of high-frequency electronic circuits and magnetorheological smart material application technology, specifically to a high-frequency ripple generation circuit and a magnetorheological fluid heating system, which is particularly suitable for low-temperature start-up heating scenarios of equipment such as vehicle-mounted magnetorheological dampers and magnetorheological brakes. It can simultaneously achieve efficient heating of magnetorheological fluid and precise control of magnetic field, meeting the integration and high reliability requirements of vehicle-mounted environments.

[0026] See Figures 1-3 An embodiment of the present invention provides a magnetorheological fluid heating system based on a high-frequency ripple generation circuit, comprising a power supply and control module, a high-frequency ripple generation module, a high-frequency coupling module, a magnetorheological fluid heating module, and a temperature monitoring and feedback module; the power supply and control module and the input terminal of the high-frequency ripple generation module are communicatively connected, the output terminal of the high-frequency ripple generation module is communicatively connected to the input terminal of the high-frequency coupling module, the output terminal of the high-frequency coupling module is communicatively connected to the magnetorheological fluid heating module, and the magnetorheological fluid heating module is communicatively connected to the temperature monitoring and feedback module; The power supply and control module's power supply terminal is connected to the vehicle / industrial power supply; the control terminal of the power supply and control module is connected to the MCU; the vehicle / industrial power supply is connected to the DC-DC conversion module; the MCU is connected to the frequency / amplitude adjustment and temperature feedback judgment module, and the frequency / amplitude adjustment and temperature feedback judgment module is communicatively connected to the temperature monitoring feedback module.

[0027] The power supply and control module of this invention is responsible for the stable operation and intelligent control of the entire system. It converts the 12V power supply from the vehicle / industrial system into different voltage levels required by various units, such as boosting to 24V for high-frequency power circuits and stepping down to an adjustable 0-12V for magnetic control. Signal generation and driving: The MCU is the control core, generating complementary PWM square wave signals, which, after power amplification, precisely drive the switching devices in the subsequent stages. It receives feedback signals from temperature and current, and dynamically adjusts the frequency and amplitude of the output drive signal through a built-in PID algorithm to achieve constant temperature control and magnetic field stability. It integrates hardware and software protection mechanisms such as overcurrent sampling and over-temperature detection, enabling it to respond to faults and cut off the output within microseconds, forming a double safety mechanism with the fuse.

[0028] The high-frequency ripple generator module is responsible for efficiently converting DC power into high-frequency AC power. Under the control of the MCU drive signal, two GaN switches alternately turn on and off at extremely high frequencies, chopping the DC voltage into a high-frequency square wave. This ensures that the voltage or current is zero at the moment the switches are turned on or off, thereby reducing switching losses by more than 80% and greatly improving efficiency and reliability.

[0029] The high-frequency coupling module is responsible for the safe and efficient transfer of high-frequency energy. An isolation transformer completely isolates the preceding high-frequency power circuit from the control circuit and the DC magnetic control circuit. This prevents power ground noise from interfering with sensitive MCU and sensor signals, forming the cornerstone of the system's high reliability. The transformer magnetically couples the high-frequency energy from the primary to the secondary side, matching the impedances of the preceding and following stages to achieve maximum energy transfer.

[0030] The magnetorheological fluid heating module utilizes a single excitation coil. When a high-frequency ripple current passes through, the high-frequency alternating magnetic field generated by the coil directly generates heat in the magnetic particles (hysteresis loss) and adjacent magnetic core (eddy current loss) of the magnetorheological fluid, thus efficiently and uniformly heating the fluid. Using the same coil, when damping characteristics need adjustment, the DC-controlled magnetorheological branch provides DC current, generating a stable bias magnetic field for real-time and precise control of the magnetorheological fluid's rheological properties. The magnetic core and containment cavity directly reuse the structure of the original magnetorheological damper, eliminating the need for additional independent heating elements.

[0031] The temperature monitoring and feedback module achieves a closed-loop precise temperature control. It employs a K-type thermocouple directly immersed in the fluid to rapidly sense temperature changes. The module amplifies the weak millivolt-level signal from the thermocouple and automatically performs cold junction compensation internally, outputting a standard 10mV / ℃ voltage signal. This integrated design greatly simplifies the circuitry and improves measurement accuracy and anti-interference capabilities. The processed temperature signal is transmitted in real-time to the MCU's ADC, providing precise input for the PID control algorithm, which is crucial for the system to achieve high-precision temperature control of ±0.5℃.

[0032] This invention is highly efficient and energy-saving, with rapid low-temperature start-up: energy conversion efficiency is greatly improved, and the energy-saving effect is also better. In low-temperature environments, the system can heat the magnetorheological fluid from -20℃ to the operating temperature of 20℃ within 18 minutes, with a start-up response time of ≤10ms, effectively solving the problem of low-temperature failure of magnetorheological devices.

[0033] This invention is highly integrated, saving space and cost: the heating and magnetic control functions reuse the same excitation coil and magnetic circuit structure, eliminating the need for a separate heater such as a PTC, which greatly reduces the size of the equipment, lowers material costs and assembly complexity, and thus greatly reduces the overall system failure rate.

[0034] This invention features extremely high control precision: temperature control accuracy ±0.5℃, magnetic field regulation accuracy ±0.05T, and an independent DC magnetic control branch combined with current sampling feedback to achieve precise magnetic control.

[0035] This invention features a fast response time: temperature sampling response ≤50ms, magnetic response time ≤10ms, meeting real-time control requirements.

[0036] This invention provides multiple protections, greatly improving the robustness and security of the system, with a mean time between failures (MTBF) of ≥150,000 hours.

[0037] This invention solves the four core challenges of heating efficiency, control accuracy, system integration, and reliability in the low-temperature application of magnetorheological fluids through a systematic innovation of "high-efficiency soft-switching topology + magnetoelectric-thermal function multiplexing + high-precision integrated sensing + automotive-grade reliability design". It provides an excellent technical solution for the reliable application of magnetorheological devices such as intelligent suspensions, clutches, and brakes in all climates.

[0038] Furthermore, the power supply and control module includes a DC power supply unit and a drive control unit; the DC power supply unit includes an on-board power supply, and the drive control unit includes a power amplifier, a switching unit, an STM32 microcontroller, a thermocouple conditioning chip, and an output module; the on-board power supply is connected to the 12V DC power supply module, the boost module, and the buck module via fuses respectively. The 12V DC power supply module is electrically connected to the power amplifier through the first filter circuit; the boost module is electrically connected to the switching unit through the second filter circuit; and the buck module is electrically connected to the STM32 microcontroller and the thermocouple conditioning chip through the third filter circuit. The switching unit is electrically connected to the output module; The output of the STM32 microcontroller is electrically connected to the power amplifier through a current-limiting resistor and an AC coupling capacitor; the thermocouple conditioning chip is communicatively connected to the input of the STM32 microcontroller through a filter capacitor. The source sampling resistor of the switching power supply is connected to the input of the STM32 microcontroller via an automotive-grade operational amplifier; the magnetizing coil sampling resistor is connected to the input of the STM32 microcontroller via another automotive-grade operational amplifier.

[0039] This invention features a dual-path independent DC power supply unit with precise control of the drive control unit and soft-switching coordination of the switching resonant unit, significantly improving energy conversion efficiency and saving 40% energy compared to traditional hard-switching topologies; low-temperature start-up response time ≤10ms; high unit efficiency; high functional integration: the excitation coil achieves "heating + magnetic control" reuse, eliminating the need for independent heating elements, reducing equipment size by 15%, and lowering system failure rate by 60%; the AD8495 integrates cold junction compensation and amplification functions, simplifying the temperature feedback link and reducing the number of components; Excellent control precision: heating temperature control accuracy ±0.5℃, magnetic field regulation accuracy ±0.05T, low-temperature start-up response time of magnetorheological fluid ≤10ms, AD8495 solution makes temperature sampling response time ≤50ms, and the error after calibration ≤±0.3℃, significantly improving the reliability of temperature control.

[0040] The high-frequency power supply branch of the dual-power supply topology of the DC power supply unit: receives 12V vehicle power, boosts it to 24V through an automotive-grade DC-DC boost module (model EV360-T1224, AEC-Q100 certified), outputs current ≥3.5A, and ripple ≤50mV, providing high-frequency energy for the switching unit and resonant unit; The DC magnetic control branch receives a 12V vehicle power supply and outputs an adjustable voltage of 0~12V through an automotive-grade DC-DC voltage regulator module. The ripple is ≤50mV and the current is ≥2A, providing magnetic control energy for the magnetorheological heating-magnetic control multiplexing unit. The high-frequency power supply branch of the overcurrent protection group is connected in series with a 3A fast-blow fuse, model 0451003.MRL, AEC-Q200 certified, with a response time ≤5ms, to prevent overcurrent in the switching unit and resonant unit; the DC magnetization branch is connected in series with a 2A fast-blow fuse, model 0451002.MRL, AEC-Q200 certified, with a response time ≤2ms, to prevent overcurrent in the excitation coil; The core control chip of the drive control unit adopts an automotive-grade STM32F103x8T6-Q microcontroller with a main frequency of 72MHz. It supports complementary output of TIM timer, 12-bit ADC sampling, and has an operating temperature range of -40℃ to 105℃, meeting the automotive-grade reliability requirements for multi-unit collaborative control in vehicles. The switching drive module generates complementary drive signals: two complementary square waves with a duty cycle of <50% are output through the TIM1 timer, with a dead time of 50ns~100ns to avoid the two transistors of the switching unit from conducting at the same time; signal amplification: the drive signal is amplified to +13dBm by the automotive-grade power amplifier module to meet the gate drive requirements (0~5V) of the GaN device in the switching unit. Magnetic field closed loop: The current of the excitation coil is collected by sampling resistor (0.01Ω alloy resistor), the magnetic field strength is calculated, and the output voltage of DC control magnetic branch is adjusted to achieve precise control of magnetic field from 0 to 2T, with magnetic response time ≤10ms; Overcurrent feedback: A 0.01Ω sampling resistor is connected in series with the source of the switching unit. The current signal is amplified by an automotive-grade operational amplifier and input to the STM32 ADC interface. When the overcurrent is ≥5A, the drive signal is shut off within 1μs to achieve hardware-level protection.

[0041] Furthermore, the STM32 microcontroller includes a TIM1 timer and a 12-bit ADC module; the thermocouple conditioning chip is communicatively connected to the 12-bit ADC module of the STM32 microcontroller through a filter capacitor.

[0042] The feedback control ADC sampling frequency is 10Hz, which collects the standard voltage signal output by AD8495. The temperature of the magnetorheological fluid is calculated by the formula "T=V_out / 10mV / ℃". After linear calibration, the temperature error is ≤±0.3℃. The drive signal frequency is dynamically adjusted from 5Hz to 18MHz based on the PID algorithm, with a control cycle of 100ms. When the temperature deviation is ≥1℃, the PID fast adjustment is triggered, and the temperature control accuracy is ±0.5℃.

[0043] Furthermore, the magnetorheological fluid heating module includes a DC power supply E1, a fuse F2, a MOSFET Q1, a MOSFET Q2, a capacitor C4, an inductor H, a transformer F3, a capacitor C6, a fuse F1, a DC power supply E2, and an excitation coil L1. The positive terminal of the DC power supply E1 is connected to one end of the fuse F2, the other end of the fuse F2 is connected to the drain of the MOSFET Q1, the source of the MOSFET Q1 is connected to the drain of the MOSFET Q2, and the source of the MOSFET Q2 is connected to the negative terminal of the DC power supply E1. The gate of MOSFET Q1 is connected to an input signal; The gate of MOSFET Q2 is connected to another input signal; The drain of MOSFET Q2 is connected to one end of inductor H, and the other end of inductor H is connected to one end of the high-voltage side of transformer F3; the source of MOSFET Q2 is connected to one end of capacitor C4, and the other end of capacitor C4 is connected to the other end of the high-voltage side of transformer F3. One end of the low-voltage side of transformer F3 is connected to one end of capacitor C6, the other end of capacitor C6 is connected to one end of fuse F1, and the other end of fuse F1 is connected to the positive terminal of DC power supply E2. The negative terminal of DC power supply E2 is connected to the other end of the low-voltage side of transformer F3; One end of the excitation coil L1 is connected to the connecting wire between capacitor C6 and fuse F1, and the other end of the excitation coil L1 is connected to the negative terminal of DC power supply E2.

[0044] This invention boasts outstanding reliability, featuring triple protection: overcurrent fuse for the DC power supply unit, hardware feedback for the drive control unit, and peak suppression for the switching unit. The mean time between failures (MTBF) is ≥150,000 hours. The integrated design of the AD8495 reduces potential failure points and is suitable for complex automotive environments.

[0045] Workflow of the present invention

[0046] 1. Power supply startup phase: The vehicle's 12V power supply is connected to the DC power supply unit, the boost module outputs 24V to the switching unit and resonant unit, and the voltage regulator module outputs an initial 3V to the excitation coil; the filter capacitor starts working to filter out power supply noise, and the fuse enters standby mode; 2. Drive signal generation stage: The drive control unit STM32F103x8T6-Q starts up, and the TIM1 timer outputs a complementary drive signal with a dead time of 50ns. After being amplified by the power amplifier module, it is transmitted to the gate of the GaN device in the switching unit to control Q1 and Q2 to conduct alternately. 3. High-frequency ripple generation stage: When switching units Q1 and Q2 are alternately turned on, the primary side LC circuit (220nH + 2.2nF) of the resonant unit generates a 10MHz high-frequency ripple. Zero-current turn-on / turn-off of the switching transistor is achieved through ZCS technology, reducing switching losses by 80%. 4. Energy Coupling and Heating Stage: The high-frequency ripple is magnetically coupled to the secondary side through the resonant unit isolation transformer. After the DC blocking capacitor blocks the DC, it is injected into the excitation coil. The coil generates hysteresis / eddy current loss, which directly heats the magnetorheological fluid. At the same time, the DC control magnetic branch provides DC current to the coil, generating a controllable magnetic field. 5. Closed-loop control stage: Temperature feedback: A K-type thermocouple collects the fluid temperature. The probe signal is conditioned (cold junction compensation + amplification) by an AD8495 chip and outputs a standard voltage signal. The STM32 microcontroller collects the ADC signal at a frequency of 10Hz, calculates the temperature using a formula, and performs linear calibration. The drive signal frequency is dynamically adjusted based on a PID algorithm: when the temperature is <20℃, it is increased to 12~18MHz, with a power of 60~80W and a heating rate ≥2℃ / min; when the temperature is >30℃, it is reduced to 5~8MHz, with a power of 30~50W; when the temperature is 20℃~30℃, the frequency is maintained at 8~12MHz, with a temperature control accuracy of ±0.5℃. Magnetic field control: A sampling resistor collects the coil current, calculates the magnetic field strength, and adjusts the output voltage of the voltage regulator module to maintain the target magnetic field. 6. Protection triggering stage: If the high-frequency circuit current is ≥3A or the DC circuit current is ≥2A, the corresponding fuse will blow; the overcurrent feedback circuit of the drive control unit will detect the overcurrent signal synchronously and shut down the drive signal within 1μs; when the thermocouple detects that the temperature exceeds the threshold, the heating circuit will be shut down immediately and the fault will be reported.

[0047] Furthermore, a capacitor C2 is connected in parallel between the drain and source of the MOS transistor Q1; The auxiliary resonant component of this invention: one automotive-grade electrode is connected in parallel across the source and drain terminals of Q1. 100nF ceramic capacitor with high-frequency equivalent resistance ≤0.1Ω helps achieve zero-voltage turn-off (ZVS) and suppresses switching spike voltage. Furthermore, a capacitor C3 is connected in parallel between the drain and source of the MOS transistor Q2; The auxiliary resonant component of this invention: One automotive-grade [device] is connected in parallel across the source and drain terminals of Q2. 100nF ceramic capacitor with high-frequency equivalent resistance ≤0.1Ω helps achieve zero voltage turn-off (ZVS) and suppresses switching spike voltage; Furthermore, a capacitor C5 is connected in parallel across the high-voltage side of the transformer F3.

[0048] In high-frequency half-bridge / full-bridge circuits, a low-impedance freewheeling or resonant circuit is provided for the transformer's magnetizing current and leakage inductance energy. During the "dead time" when the switching transistors (such as GaN transistors) of the upper and lower bridge arms are both off, the magnetic energy stored in the inductance (including the magnetizing inductance and leakage inductance) of the transformer's primary winding needs to be released. The parallel capacitor C5 and this inductor form a temporary LC resonant circuit. This resonant process causes the voltage Vds across the switching transistor to naturally oscillate downward from its peak value. This is a core technology for improving system efficiency, reducing heat generation, and allowing higher frequency operation.

[0049] Furthermore, the DC power supply E1 is a 24V DC power supply.

[0050] High-frequency heating requires transferring sufficient energy to the magnetorheological fluid through hysteresis and eddy current effects, especially during low-temperature startup where rapid heating is necessary, requiring a heating rate ≥2℃ / min and a power of 60-80W. A 24V power supply provides sufficient potential energy to the high-frequency power supply branch, ensuring that the switching and resonant units can operate at a sufficiently high power level to meet the power requirements of rapid heating.

[0051] Furthermore, the DC power supply E2 is a 12V DC power supply.

[0052] The 12V upper limit provides sufficient voltage margin for magnetic field control, ensuring a rapid response from the power supply, even with slight changes in coil resistance at low temperatures or when a strong, instantaneous magnetic field is required. At the same time, this voltage level is far below the withstand voltage of typical devices, operating within a very safe electrical range.

[0053] Furthermore, the switching unit is a GaN device, model EPC2045.

[0054] Two automotive-grade GaNHEMT devices are used to form a half-bridge structure (Q1 is the upper bridge arm and Q2 is the lower bridge arm). Device parameters: withstand voltage 60V, rated current 12A, on-resistance 25mΩ, switching frequency ≤18MHz, and support for zero-current switching (ZCS). This invention has strong vehicle adaptability: all unit components are AEC-Q100 / Q200 certified, have an operating temperature of 40℃~125℃, are resistant to 2000Hz vibration, and meet electromagnetic compatibility requirements.

[0055] Each drive signal is connected in series with a 10Ω gate resistor to limit the gate current and prevent damage to the GaN device gate due to overvoltage; a fast recovery diode is connected in reverse parallel between the drain and source.

[0056] Performance testing and verification of this invention; Coordinated performance of each unit: DC power supply unit output ripple ≤50mV, drive control unit PID adjustment response time ≤100ms, and energy conversion efficiency of switch-resonant unit is greatly improved; Heating performance: At -20℃, the magnetorheological fluid can be heated to 20℃ within 18 minutes with a temperature control accuracy of ±0.4℃ and a temperature difference of ≤3℃ for heating uniformity. Thermocouple feedback performance: AD8495 cold junction compensation error ≤0.2℃, temperature sampling response time ≤50ms, abnormal temperature trigger protection time ≤1ms; Environmental adaptability: After working in a -40℃ low-temperature chamber for 48 hours, the heating rate remains stable at 2℃ / min; after working in a 125℃ high-temperature chamber, the component performance degradation is ≤4%; after 2000Hz vibration for 24 hours, the circuit connection remains secure. Electromagnetic compatibility: CISPR25 Class 3 test, radiated disturbance in the 30MHz~1GHz band ≤26dBμV / m; The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0057] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A magnetorheological fluid heating system based on a high-frequency ripple generation circuit, characterized in that, It includes a power supply and control module, a high-frequency ripple generation module, a high-frequency coupling module, a magnetorheological fluid heating module, and a temperature monitoring and feedback module; the power supply and control module and the input terminal of the high-frequency ripple generation module are communicatively connected, the output terminal of the high-frequency ripple generation module is communicatively connected to the input terminal of the high-frequency coupling module, the output terminal of the high-frequency coupling module is communicatively connected to the magnetorheological fluid heating module, and the magnetorheological fluid heating module is communicatively connected to the temperature monitoring and feedback module. The power supply and control module's power supply terminal is connected to the vehicle / industrial power supply; the control terminal of the power supply and control module is connected to the MCU; the vehicle / industrial power supply is connected to the DC-DC conversion module; the MCU is connected to the frequency / amplitude adjustment and temperature feedback judgment module, and the frequency / amplitude adjustment and temperature feedback judgment module is communicatively connected to the temperature monitoring feedback module.

2. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 1, characterized in that, The power supply and control module includes a DC power supply unit and a drive control unit; the DC power supply unit includes an on-board power supply, and the drive control unit includes a power amplifier, a switching unit, an STM32 microcontroller, a thermocouple conditioning chip, and an output module; the on-board power supply is connected to the 12V DC power supply module, the boost module, and the buck module via fuses respectively. The 12V DC power supply module is electrically connected to the power amplifier through the first filter circuit; the boost module is electrically connected to the switching unit through the second filter circuit; and the buck module is electrically connected to the STM32 microcontroller and the thermocouple conditioning chip through the third filter circuit. The switching unit is electrically connected to the output module; The output of the STM32 microcontroller is electrically connected to the power amplifier through a current-limiting resistor and an AC coupling capacitor; the thermocouple conditioning chip is communicatively connected to the input of the STM32 microcontroller through a filter capacitor. The source sampling resistor of the switching power supply is connected to the input terminal of the STM32 microcontroller via an automotive-grade operational amplifier. The excitation coil sampling resistor is connected to the input of the STM32 microcontroller via another automotive-grade operational amplifier.

3. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 2, characterized in that, The STM32 microcontroller includes a TIM1 timer and a 12-bit ADC module; the thermocouple conditioning chip is connected to the 12-bit ADC module of the STM32 microcontroller through a filter capacitor.

4. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 2, characterized in that, The magnetorheological fluid heating module includes a DC power supply E1, a fuse F2, a MOSFET Q1, a MOSFET Q2, a capacitor C4, an inductor H, a transformer F3, a capacitor C6, a fuse F1, a DC power supply E2, and an excitation coil L1. The positive terminal of the DC power supply E1 is connected to one end of the fuse F2, the other end of the fuse F2 is connected to the drain of the MOSFET Q1, the source of the MOSFET Q1 is connected to the drain of the MOSFET Q2, and the source of the MOSFET Q2 is connected to the negative terminal of the DC power supply E1. The gate of MOSFET Q1 is connected to an input signal; The gate of MOSFET Q2 is connected to another input signal; The drain of MOSFET Q2 is connected to one end of inductor H, and the other end of inductor H is connected to one end of the high-voltage side of transformer F3; the source of MOSFET Q2 is connected to one end of capacitor C4, and the other end of capacitor C4 is connected to the other end of the high-voltage side of transformer F3. One end of the low-voltage side of transformer F3 is connected to one end of capacitor C6, the other end of capacitor C6 is connected to one end of fuse F1, and the other end of fuse F1 is connected to the positive terminal of DC power supply E2. The negative terminal of DC power supply E2 is connected to the other end of the low-voltage side of transformer F3; One end of the excitation coil L1 is connected to the connecting wire between capacitor C6 and fuse F1, and the other end of the excitation coil L1 is connected to the negative terminal of DC power supply E2.

5. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 4, characterized in that, A capacitor C2 is connected in parallel between the drain and source of the MOS transistor Q1.

6. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 5, characterized in that, A capacitor C3 is connected in parallel between the drain and source of the MOS transistor Q2.

7. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 6, characterized in that, A capacitor C5 is connected in parallel across the two ends of the high-voltage side of the transformer F3.

8. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 7, characterized in that, The DC power supply E1 is a 24V DC power supply.

9. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 8, characterized in that, The DC power supply E2 is a 12V DC power supply.

10. The magnetorheological fluid heating system based on a high-frequency ripple generation circuit according to claim 9, characterized in that, The switching unit is a GaN device, model EPC2045.

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