Driving circuit structure of magnetorheological damper and control method

Abstract

The invention relates to the technical field of magneto-rheological damper control circuits, in particular to a magneto-rheological damper drive circuit structure and a control method, and the magneto-rheological damper drive circuit structure comprises a power supply protection circuit, a power supply management circuit, a booster circuit and an H-bridge drive circuit; the input end of the power supply protection circuit is connected with a vehicle-mounted storage battery and is used for carrying out anti-reverse connection and anti-surge protection on an input power supply; the input end of the power management circuit is connected with the output end of the power protection circuit, and the H-bridge driving circuit is adopted, so that the response performance and adaptability of the magnetorheological damper are remarkably improved; on one hand, the boost circuit raises the voltage of the storage battery, thereby improving the power supply voltage of the H-bridge drive circuit, effectively overcoming the limitation of large internal resistance of the excitation coil, and ensuring the enough current output capability; on the other hand, according to the error relation between the target current and the actual current, the H-bridge working mode is switched, full-speed driving is conducted when the error is large, and accurate adjustment is conducted when the target is approached.

Description

Technical Field

[0001] This invention relates to the field of magnetorheological damper control circuit technology, and in particular to a magnetorheological damper drive circuit structure and control method. Background Technology

[0002] Magnetorheological dampers, with their significant advantages such as fast response and continuously adjustable damping force, have become a key component of the semi-active control system in modern automotive suspension systems. Their working principle involves changing the current in the excitation coil to adjust the yield stress of the magnetorheological fluid, thereby achieving real-time control of the damping force, which is crucial for improving vehicle ride comfort and safety.

[0003] However, existing magnetorheological suspension drive solutions still have performance limitations. Current mainstream technologies are usually based on Buck-Converter topologies, or directly adjust the average voltage output to the coil by controlling the PWM duty cycle of the switching transistor (MOSFET), thereby controlling the average current. Due to the fast response characteristics of magnetorheological fluids, the drive current is required to have extremely high dynamic adjustment capability. The traditional Buck topology has an inherent deficiency in response speed, making it difficult to meet the millisecond-level response time requirements of the suspension system. At the same time, the single PWM voltage regulation method is often limited by the internal resistance of the excitation coil, resulting in a limited range of output current adjustment and large ripple in the output current, which affects the accuracy and stability of damping force control.

[0004] Therefore, how to solve the problem of limited output current caused by the internal resistance of the excitation coil and significantly improve the system response time has become a technical problem that urgently needs to be solved in the design of drive circuits for current magnetorheological suspension systems. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies, such as difficulty in meeting the millisecond-level response time requirements of suspension systems, and the fact that a single PWM voltage regulation method is often limited by the internal resistance of the excitation coil, resulting in a limited range of output current adjustment. Therefore, this invention proposes a magnetorheological damper drive circuit structure and control method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The present invention proposes a magnetorheological damper drive circuit structure in the first aspect, including a power protection circuit, a power management circuit, a boost circuit and an H-bridge drive circuit;

[0008] The input terminal of the power protection circuit is connected to the vehicle battery and is used to protect the input power from reverse connection and surge.

[0009] The input terminal of the power management circuit is connected to the output terminal of the power protection circuit, and is used to convert the protected input power into DC power and power the MCU.

[0010] The input terminal of the boost circuit is connected to the output terminal of the power protection circuit, and is used to boost the voltage of the vehicle battery to the threshold operating voltage UBR.

[0011] The power input terminal of the H-bridge drive circuit is connected to the output terminal of the boost circuit, its control signal input terminal is connected to the MCU, and its output terminal is connected to the excitation coil of the magnetorheological damper.

[0012] Furthermore, the power protection circuit includes a surge protection circuit and a reverse connection protection circuit;

[0013] The surge protection circuit includes a transient voltage suppressor diode (TVS) connected in parallel at the power input terminal.

[0014] The reverse connection protection circuit includes an ideal diode controller and an NMOS transistor. The ANODE and CATHODE pins of the ideal diode controller are connected to the source and drain of the NMOS transistor, respectively, and the GATE pin of the ideal diode controller is connected to the gate of the NMOS transistor. The ideal diode controller controls the conduction and cutoff of the NMOS transistor according to the voltage polarity between its ANODE and CATHODE pins to achieve reverse power connection protection.

[0015] Furthermore, the ideal diode controller is an SCT53600, and the NMOS transistor is a YJB5D0G06HQ.

[0016] Furthermore, the ideal diode controller also includes a VCAP pin, which is externally connected to a 0.1uF capacitor to power the internal charge pump of the ideal diode controller; the ideal diode controller also includes an EN pin, which is connected to the ANODE pin of the ideal diode controller through a 10kΩ pull-up resistor.

[0017] Furthermore, the power management circuit includes a Buck step-down chip and a low-dropout linear regulator (LDO); the Buck step-down chip is used to reduce the input voltage to a first intermediate voltage, and the LDO is used to regulate the first intermediate voltage to the operating voltage of the MCU.

[0018] Furthermore, the boost circuit includes a synchronous four-switch Buck-Boost controller for boosting the input voltage to UBR when the input voltage is lower than the threshold operating voltage UBR.

[0019] Furthermore, the H-bridge drive circuit includes an integrated driver chip and a full-bridge circuit composed of four switching transistors; the integrated driver chip is used to drive the full-bridge circuit according to the control signal of the MCU to generate a drive current with adjustable direction and magnitude, and integrates a current sampling function.

[0020] Furthermore, the integrated driver chip is DRV8244-Q1.

[0021] Furthermore, the threshold operating voltage UBR is configured to be significantly higher than a predetermined value of the vehicle battery voltage.

[0022] In a second aspect, this invention also proposes a magnetorheological damper control method based on boost multi-mode switching, which is applied to the above-mentioned circuit structure and specifically includes the following steps:

[0023] Step 1: Obtain the target current command I_ref and the real-time sampled current I_sense, and calculate the current error e = I_ref - I_sense;

[0024] Step 2: Based on the value and polarity of the current error e, control the H-bridge drive circuit to switch between three operating modes:

[0025] (1) When e ≥ Δ, enter the fast control mode and control the H-bridge drive circuit to output the maximum drive current; where Δ is the first preset positive threshold.

[0026] (2) When 0 ≤ e < Δ, enter the precise control mode and control the H-bridge drive circuit to drive in pulse width modulation mode;

[0027] (3) When e < 0, the fast decay mode is entered, and the H-bridge drive circuit is controlled to output reverse current.

[0028] The present invention proposes a magnetorheological damper drive circuit structure and control method, which has the following advantages: By adopting an H-bridge drive circuit, the response performance and adaptability of the magnetorheological damper are significantly improved. On the one hand, the boost circuit raises the battery voltage, increasing the supply voltage of the H-bridge drive circuit, effectively overcoming the limitation of the large internal resistance of the excitation coil and ensuring sufficient output current capability. On the other hand, the H-bridge operating mode is switched according to the error relationship between the target current and the actual current. When the error is large, the drive is at full speed, and when the target is approached, the adjustment is precise. This design greatly shortens the current response time and realizes rapid and precise control of the damping force of the magnetorheological damper. Attached Figure Description

[0029] Figure 1 This is a structural block diagram of the present invention;

[0030] Figure 2 This is a schematic diagram of the power protection circuit structure of the present invention;

[0031] Figure 3 This is a schematic diagram of the power control circuit structure of the present invention;

[0032] Figure 4 This is a schematic diagram of the boost circuit structure of the present invention;

[0033] Figure 5 This is a schematic diagram of the working principle of the H-bridge drive output circuit of the present invention;

[0034] Figure 6 This is a schematic diagram of the H-bridge drive output circuit structure of the present invention;

[0035] Figure 7 This is a flowchart of the H-bridge control logic of the present invention. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] Reference Figure 1-6 As an embodiment of the present invention, a magnetorheological damper driving circuit structure is disclosed, specifically the circuit structure includes a power protection circuit, a power management circuit, a boost circuit and an H-bridge driving circuit.

[0038] The input terminal of the power protection circuit is connected to the vehicle battery and is used to protect the input power from reverse connection and surge.

[0039] The input terminal of the power management circuit is connected to the output terminal of the power protection circuit, and is used to convert the protected input power into DC power and power the MCU.

[0040] The input terminal of the boost circuit is connected to the output terminal of the power protection circuit, and is used to boost the voltage of the vehicle battery to the threshold operating voltage UBR.

[0041] The power input terminal of the H-bridge drive circuit is connected to the output terminal of the boost circuit, its control signal input terminal is connected to the MCU, and its output terminal is connected to the excitation coil of the magnetorheological damper.

[0042] Please refer to Figure 2 As shown, the power protection circuit in this embodiment of the invention includes a surge protection circuit and a reverse connection protection circuit;

[0043] The surge protection circuit includes a transient voltage suppressor diode (TVS) connected in parallel at the power input terminal.

[0044] The reverse connection protection circuit includes an ideal diode controller and an NMOS transistor. The ANODE and CATHODE pins of the ideal diode controller are connected to the source and drain of the NMOS transistor, respectively, and the GATE pin of the ideal diode controller is connected to the gate of the NMOS transistor. The ideal diode controller controls the conduction and cutoff of the NMOS transistor according to the voltage polarity between its ANODE and CATHODE pins to achieve reverse power connection protection.

[0045] In an optional embodiment, the ideal diode controller in this invention is an SCT53600, and the NMOS transistor is a YJB5D0G06HQ.

[0046] Specifically, the main function of the power protection circuit in this invention is to realize surge protection and reverse connection protection. A TVS diode D010, model SM8S24A, is added to the battery power input port VBATJ for surge protection design of the power port.

[0047] The reverse connection protection circuit uses a combination of an ideal diode controller SCT53600 and an NMOS transistor YJB5D0G06HQ. The voltage between the source and drain of the MOSFET YJB5D0G06HQ is detected between the ANODE and CATHODE pins of the ideal diode controller SCT53600. When the voltage across the pins is detected to be between -11 and 50 mV, the SCT53600 operates in forward regulation mode. By adjusting the voltage from GATE to ANODE, the voltage from ANODE to CATHODE can be adjusted to 20 mV.

[0048] This closed-loop regulation scheme can adjust the shutdown of the external MOSFET under very small loads and ensure zero DC reverse current. When the voltage across the terminals is typically greater than 50 mV, the SCT53600 operates in full-on mode, at which point the voltage drop between GATE and ANODE is at its maximum to ensure that the RDS(ON) of the external MOSFET is fully conducted.

[0049] When the voltage from ANODE to CATHODE is less than -11 mV, the reverse current protection mode is entered. The GATE is internally connected to the ANODE anode to shut down the external MOSFET, thus realizing the circuit's reverse connection protection function. Output capacitors C011~C013 are used to avoid back-end power supply fluctuations, C010 is a charge pump capacitor used to drive the external MOSFET to the maximum gate drive voltage, and R010 is a current limiting resistor.

[0050] Of course, the ideal diode controller in this embodiment of the invention also includes a VCAP pin, which is externally connected to a 0.1uF capacitor to power the internal charge pump of the ideal diode controller; the ideal diode controller also includes an EN pin, which is connected to the ANODE pin of the ideal diode controller through a 10kΩ pull-up resistor.

[0051] Please refer to Figure 3 In an optional embodiment, the power management circuit of the present invention includes a Buck step-down chip and a low-dropout linear regulator (LDO); the Buck step-down chip is used to reduce the input voltage to a first intermediate voltage, and the LDO is used to regulate the first intermediate voltage to the operating voltage of the MCU.

[0052] The power management control circuit in this invention is as follows: Figure 3 As shown, its main function is to step down the vehicle battery voltage to 3.3V, providing a power input that meets the operating requirements of the MUC and other ICs. In an optional embodiment, the present invention can preferably use the automotive-grade Buck chip SCT2632QSTER and LDO chip SCT71405F33BQ-STER from Chipsys Technology to convert the battery voltage to 3.3V.

[0053] in:

[0054] Input filtering: An LC filter circuit consisting of inductor L3 and capacitor C304 is connected to the power input terminal VIN of the Buck step-down chip to filter out ripple noise in the input power supply.

[0055] Frequency setting: Resistor R303 is connected to the frequency setting pin of the Buck step-down chip to adjust the chip's switching frequency. Its calculation formula is The corresponding switching frequency can be set by configuring the resistance value of R303.

[0056] Output inductor selection: The inductance value of output inductor L3_1 is selected according to the following formula:

[0057] in, For maximum output voltage, Maximum input voltage, This is the rated output voltage. To output ripple current, The switching frequency is used; the minimum inductance value is obtained through calculation. To match the appropriate sensitivity value.

[0058] Output voltage setting: Output voltage The ratio of the voltage divider resistors R304 and R305 connected to the feedback pin is determined by the following formula: The target output voltage of 5V can be achieved by adjusting the resistance ratio of R304 and R305.

[0059] Output voltage regulation and power supply: Capacitors C308 and C309 are connected in parallel at the output terminal as energy storage capacitors to stabilize the output voltage and reduce ripple. The 5V voltage output by the Buck step-down chip is input to the LDO, where it is further regulated to generate a 3.3V voltage to power the MCU and other peripheral ICs.

[0060] Please refer to Figure 4 In some embodiments, the boost circuit of the present invention includes a synchronous four-switch Buck-Boost controller for boosting the input voltage to UBR when the input voltage is lower than the threshold operating voltage UBR.

[0061] Boost circuit, such as Figure 4 As shown, the TI LM5175 synchronous four-switch Buck-Boost power supply chip is selected. Its working principle is as follows: When the input voltage is lower than the output voltage, the chip operates in Boost mode, with internal control Q1 normally closed. When the chip controls Q2 to open and Q4 to turn on, current flows through Q1, inductor L1, and Q4 to GND, where inductor L1 stores energy. When Q4 is open and Q2 is on, inductor L1 generates a back electromotive force (EMF) with negative on the left and positive on the right, which is superimposed on the power supply voltage and discharged to the output through Q2, thus achieving voltage boost.

[0062] The specific circuit design parameters are as follows: The EN pin is set by voltage divider resistors R1 and R2 so that the chip is enabled when the input voltage VBATJ≥6V and the EN pin voltage is higher than 1.23V; the MODE pin is pulled down to GND by a 93.1kΩ resistor so that the chip operates in continuous conduction mode (CCM); the RT / SYNC pin is connected to a 48.7kΩ resistor R6.

[0063] According to the formula

[0064] RT = (1 / Fsw − 200ns) / 37pF

[0065] Set the switching frequency to 500kHz to reduce ripple; connect a 0.1uF capacitor C3 to the SS pin.

[0066] According to the formula

[0067]

[0068] Set a soft-start time of 16ms; the compensation network consists of C6, R7 and C5 for pole suppression; C7 is a slope compensation capacitor;

[0069] According to the formula

[0070]

[0071] The current is calculated to be 880pF to stabilize the current; the average current limit is set on the ISN3(+) and ISNS(-) pins through a 1.5mΩ sampling resistor R13;

[0072] according to Set the limit value to 20A;

[0073] Output inductor L1 according to

[0074]

[0075] The calculated value is 3.3uH; the output voltage is set to 30V.

[0076] pass ( Select voltage divider resistors R9 as 750kΩ and R8 as 20kΩ; C8 and C10 are bootstrap capacitors.

[0077] Furthermore, according to the maximum current formula

[0078]

[0079] and sampling resistor formula

[0080] Accounting;

[0081] exist hour The current rating is 74A, and the sampling resistor is 1.5mΩ. The power switching transistor is Infineon IAUCN10S7N021, which has a withstand voltage of 100V, a maximum current of 220A, and an on-resistance of 2.1mΩ, meeting the design requirements.

[0082] In an optional embodiment, the H-bridge driving circuit of the present invention includes an integrated driver chip and a full-bridge circuit composed of four switching transistors; the integrated driver chip is used to drive the full-bridge circuit according to the control signal of the MCU to generate a drive current with adjustable direction and magnitude, and integrates a current sampling function.

[0083] Specifically, the integrated driver chip described in this embodiment of the invention is DRV8244-Q1.

[0084] The working principle of the H-bridge drive output circuit is as follows: Figure 5As shown, the microcontroller (MCU) controls the MOSFETs Q1-Q4 via a driver chip to achieve current flow in different directions. When MOSFETs Q1 and Q4 are closed and Q2 and Q3 are open, the current flow is UBR→Q1→OUT1→load→OUT2→Q4→GND.

[0085] When the current commutation control is in effect, the control MOSFETs Q2 and Q3 are closed, while Q1 and Q4 are open. At this time, the current flow is UBR → Q2 → OUT2 → load → OUT1 → Q3 → GND.

[0086] This case study uses the TI DRV8244-Q1 automotive-grade H-bridge driver with integrated current sensing and feedback. The specific driver circuit design is as follows: Figure 6 As shown;

[0087] The DRV8244-Q1 driver chip is powered directly from a constant-voltage UBR supply. This allows it to adapt to magnetorheological dampers with varying internal resistances, ensuring that the input current covers a wide range of dampers with different resistances. This prevents the required output current from failing to meet standards due to supply voltage limitations when the coil's internal resistance increases. The chip integrates an internal current sensor; only an external sampling resistor is needed. The actual current is determined by the sensor's internal current acquisition mechanism.

[0088] , ;

[0089] Where I is the actual output current of the H-bridge; VADC_Current is the acquired voltage; Rsense is the adapted current sampling resistor; and 4750 is the current scaling factor.

[0090] The truth table controlled by this chip is shown in Table 1.

[0091] Table 1 Control Truth Table

[0092] nSLEEP DRVOFF PH / IN2 EN / IN1 H+ H- 0 X X X High resistance state High resistance state 1 1 0 0 High resistance state High resistance state 1 0 0 1 L H 1 0 1 0 H L 1 0 1 1 High resistance state High resistance state

[0093] It should be noted that, in the embodiments of the present invention, the threshold operating voltage UBR is configured to be significantly higher than a predetermined value of the vehicle battery voltage.

[0094] Please refer to the attached diagram for details, which is a flowchart of the H-bridge control logic. Furthermore, the second aspect of this invention proposes a magnetorheological damper control method based on boost multi-mode switching, applied to the circuit structure described above, comprising the following steps:

[0095] Step 1: Obtain the target current command I_ref and the real-time sampled current I_sense, and calculate the current error e = I_ref - I_sense;

[0096] Step 2: Based on the value and polarity of the current error e, control the H-bridge drive circuit to switch between three operating modes:

[0097] (1) When e ≥ Δ, enter the fast control mode and control the H-bridge drive circuit to output the maximum drive current; where Δ is the first preset positive threshold.

[0098] (2) When 0 ≤ e < Δ, enter the precise control mode and control the H-bridge drive circuit to drive in pulse width modulation mode;

[0099] (3) When e < 0, the fast decay mode is entered, and the H-bridge drive circuit is controlled to output reverse current.

[0100] In this embodiment, Δ is taken as 0.5 A;

[0101] The specific switching logic is as follows:

[0102] Quick Control Mode: When Time (e.g.) (Taking a value of 0.5A), it is determined that the actual current is much smaller than the target current. At this time, the controller controls the H-bridge drive circuit to output at full speed, that is, controls the MOS switches Q1 and Q4 to conduct, driving with the maximum current that the shock absorber can withstand, so that the excitation coil current rises rapidly and the response time is shortened;

[0103] Precision control mode: When When the error is between 0 and 0.5A, the actual current is determined to be close to the target current. At this time, the controller controls the MOS switches Q1 and Q4 to fine-tune the current through a high-frequency PWM (pulse width modulation) signal, so as to accurately stabilize the current at the target current value and eliminate steady-state error.

[0104] Fast decay mode: when When the actual current exceeds the target current, the controller controls the H-bridge drive circuit to output a reverse voltage (i.e., controls Q2 and Q3 to conduct), causing a back electromotive force to be generated across the inductor, and the current flowing through the excitation coil rapidly decays to the target value.

[0105] Through the above-mentioned multi-mode switching strategy, the present invention can achieve rapid current tracking when the error is large, and ensure the control accuracy of the current when the error is small, thereby significantly improving the dynamic response performance and damping control effect of the magnetorheological damper.

[0106] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A magnetorheological damper drive circuit structure, characterized in that, Includes power protection circuit, power management circuit, boost circuit and H-bridge drive circuit; The input terminal of the power protection circuit is connected to the vehicle battery and is used to protect the input power from reverse connection and surge. The input terminal of the power management circuit is connected to the output terminal of the power protection circuit, and is used to convert the protected input power into DC power and power the MCU. The input terminal of the boost circuit is connected to the output terminal of the power protection circuit, and is used to boost the voltage of the vehicle battery to the threshold operating voltage UBR. The power input terminal of the H-bridge drive circuit is connected to the output terminal of the boost circuit, its control signal input terminal is connected to the MCU, and its output terminal is connected to the excitation coil of the magnetorheological damper.

2. The magnetorheological damper drive circuit structure according to claim 1, characterized in that: The power protection circuit includes a surge protection circuit and a reverse connection protection circuit. The surge protection circuit includes a transient voltage suppressor diode (TVS) connected in parallel at the power input terminal. The reverse connection protection circuit includes an ideal diode controller and an NMOS transistor. The ANODE and CATHODE pins of the ideal diode controller are connected to the source and drain of the NMOS transistor, respectively, and the GATE pin of the ideal diode controller is connected to the gate of the NMOS transistor. The ideal diode controller controls the conduction and cutoff of the NMOS transistor according to the voltage polarity between its ANODE and CATHODE pins to achieve reverse power connection protection.

3. The magnetorheological damper drive circuit structure according to claim 2, characterized in that: The ideal diode controller is an SCT53600, and the NMOS transistor is a YJB5D0G06HQ.

4. The magnetorheological damper drive circuit structure according to claim 2, characterized in that: The ideal diode controller also includes a VCAP pin, which is externally connected to a 0.1uF capacitor to power the internal charge pump of the ideal diode controller; the ideal diode controller also includes an EN pin, which is connected to the ANODE pin of the ideal diode controller through a 10kΩ pull-up resistor.

5. The magnetorheological damper drive circuit structure according to claim 1, characterized in that: The power management circuit includes a Buck step-down chip and a low-dropout linear regulator (LDO); the Buck step-down chip is used to reduce the input voltage to a first intermediate voltage, and the LDO is used to regulate the first intermediate voltage to the operating voltage of the MCU.

6. The magnetorheological damper drive circuit structure according to claim 1, characterized in that: The boost circuit includes a synchronous four-switch Buck-Boost controller for boosting the input voltage to UBR when the input voltage is lower than the threshold operating voltage UBR.

7. The magnetorheological damper drive circuit structure according to claim 1, characterized in that: The H-bridge drive circuit includes an integrated driver chip and a full-bridge circuit consisting of four switching transistors; the integrated driver chip is used to drive the full-bridge circuit according to the control signal of the MCU to generate a drive current with adjustable direction and magnitude, and integrates a current sampling function.

8. The magnetorheological damper drive circuit structure according to claim 7, characterized in that: The integrated driver chip is DRV8244-Q1.

9. The magnetorheological damper drive circuit structure according to claim 1, characterized in that: The threshold operating voltage UBR is configured to be significantly higher than a predetermined value for the vehicle battery voltage.

10. A control method for a magnetorheological damper based on boost multi-mode switching, characterized in that, The circuit structure described in any one of claims 1-9 is applied to the circuit structure comprising the following steps: Step 1: Obtain the target current command I_ref and the real-time sampled current I_sense, and calculate the current error e = I_ref - I_sense; Step 2: Based on the value and polarity of the current error e, control the H-bridge drive circuit to switch between three operating modes: (1) When e ≥ Δ, enter the fast control mode and control the H-bridge drive circuit to output the maximum drive current; where Δ is the first preset positive threshold. (2) When 0 ≤ e < Δ, enter the precise control mode and control the H-bridge drive circuit to drive in pulse width modulation mode; (3) When e < 0, the fast decay mode is entered, and the H-bridge drive circuit is controlled to output reverse current.

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