Brushless direct current motor driving circuit for intelligent knob hand feeling control and analysis method of brushless direct current motor driving circuit

Abstract

The invention discloses a brushless direct current motor drive circuit for intelligent knob hand feeling control and an analysis method thereof, the brushless direct current motor drive circuit comprises a motor control chip, the eighteenth pin of the motor control chip is electrically connected with a capacitor C46, the capacitor C46 is connected with an electrolytic capacitor EC5 in parallel, the capacitor C46 is connected with a capacitor C47 in parallel, the thirty-third pin of the motor control chip is electrically connected with an inductor FB3, and the inductor FB3 is electrically connected with the capacitor EC5. A capacitor C50 is electrically connected between the inductor FB3 and the thirty-third pin, the capacitor C50 is connected with a capacitor C48 in parallel, the inductor FB3 is electrically connected with a capacitor C51, the thirty-fifth pin of the motor control chip is electrically connected with a capacitor C53, the capacitor C53 is connected with a capacitor C52 in parallel, the first pin of the motor control chip is electrically connected with a resistor R88, and a resistor R85 is electrically connected between the resistor R88 and the first pin. The intelligent knob can be adapted to the brushless direct current motor for driving and controlling the hand feeling of the intelligent knob, the control of the brushless direct current motor on the torque breaks through the limitation of a mechanical structure, and highly-customized and dynamically-adjustable interactive experience is achieved.

Description

Technical Field

[0001] This invention relates to the field of brushless DC motor technology, and more specifically, to a brushless DC motor drive circuit for intelligent knob touch control and its analysis method. Background Technology

[0002] Traditional mechanical knobs provide tactile feedback to users through physical structures (such as damping grease, ratchet, and springs), including tactile feedback such as resistance, scale, and limit. This tactile feedback is crucial for precise operation and user experience. However, once this mechanical structure is determined, its feel remains fixed and cannot be adapted to different application scenarios or user preferences.

[0003] Existing technologies include electric knob solutions that use stepper motors or ordinary DC motors in conjunction with clutches to attempt to simulate variable tactile feedback. However, stepper motors are prone to vibration and noise at low speeds, and torque control is discontinuous; solutions using ordinary DC motors with mechanical structures suffer from slow response, complex structures, and difficulty in simulating subtle tactile sensations. Summary of the Invention

[0004] This invention overcomes the shortcomings of the prior art and proposes a brushless DC motor drive circuit for intelligent knob tactile control. It can be adapted to drive and control the tactile feel of intelligent knobs. The brushless DC motor's torque control breaks the limitations of mechanical structure and realizes a highly customized and dynamically adjustable interactive experience.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A brushless DC motor drive circuit for intelligent rotary knob tactile control includes a motor control chip. The eighteenth pin of the motor control chip is electrically connected to a capacitor C46. An electrolytic capacitor EC5 and a capacitor C47 are connected in parallel with C46. The thirty-third pin of the motor control chip is electrically connected to an inductor FB3. A capacitor C50 is connected between inductor FB3 and the thirty-third pin. A capacitor C48 is connected in parallel with C50. Inductor FB3 is electrically connected to a capacitor C51. The thirty-fifth pin of the motor control chip is electrically connected to a capacitor C53. A capacitor C53 is connected in parallel with a capacitor C52. The first pin of the motor control chip is electrically connected to a resistor R88. A resistor R85 is connected between resistor R88 and the first pin. The second pin of the motor control chip is electrically connected to a resistor R89. A resistor R86 is electrically connected between the second pin and the third pin. A capacitor C56 is electrically connected to the thirty-sixth pin of the motor control chip. A capacitor C54 is connected in parallel with the capacitor C56. A capacitor C49 is electrically connected to the fifteenth pin of the motor control chip. A resistor R87 is electrically connected to the thirtieth pin of the motor control chip. A capacitor C57 is electrically connected to the resistor R87. A resistor R91 is electrically connected to the twenty-first pin of the motor control chip. A capacitor C58 is electrically connected to the resistor R91. A resistor R95 is electrically connected to the twenty-fifth pin of the motor control chip. A capacitor C59 is electrically connected to the resistor R95. A capacitor C60 is electrically connected to the thirty-seventh pin of the motor control chip. A capacitor C55 is electrically connected to the seventeenth pin of the motor control chip. A resistor R97 is electrically connected to the twenty-third pin of the motor control chip. A resistor R97 is electrically connected to a resistor R96.

[0006] Preferably, the fifth pin of the motor control chip is electrically connected to a resistor R90, the sixth pin of the motor control chip is electrically connected to a resistor R92, the seventh pin of the motor control chip is electrically connected to a resistor R93, and the eighth pin of the motor control chip is electrically connected to a resistor R94.

[0007] Preferably, the motor control chip model is FU6881Q1, which integrates an MCU, a MOS driver, a half-bridge, an operational amplifier, a comparator, a built-in high-voltage LDO, and a LIN.

[0008] Preferably, capacitor C46 is grounded, capacitor C50 is grounded, capacitor C51 is grounded, capacitor C53 is grounded, and capacitor C56 is grounded.

[0009] Preferably, capacitor C46 is grounded, capacitor C60 is grounded, and resistor R97 is grounded.

[0010] The present invention also provides an analysis method for the above-mentioned brushless DC motor drive circuit for intelligent knob tactile control, comprising the following steps: S1. Torque analysis of intelligent knob tactile control; S2. Determination of the tactile curve function of the intelligent knob; S3. Control process and model of brushless DC motor; Operational analysis of S4, CLARKE, and PARK; S5, Operational analysis of anti-CLARKE and anti-PARK; Analysis of S6 and SVPWM operations.

[0011] The beneficial effects of this invention are: This invention is compatible with brushless DC motors that drive and control intelligent knobs with a tactile feel. The brushless DC motor's torque control breaks the limitations of mechanical structures, achieving a highly customized and dynamically adjustable interactive experience. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating the structure of a brushless DC motor drive circuit according to a specific embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the feel curve function in a specific embodiment of the present invention; Figure 3 The following is a flowchart illustrating the motor control process in a specific embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the operation of CLRKE and PARK in a specific embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the operations of anti-CLRKE and anti-PARK in a specific embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the voltage vector of SVPWM in a specific embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the voltage synthesis of SVPWM in a specific embodiment of the present invention. Detailed Implementation

[0013] The technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] It should be noted that in the description of this invention, all directional indications (such as up, down, forward, backward, etc.) are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0015] Furthermore, in this invention, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a number" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0016] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0017] like Figure 1-7 As shown, a brushless DC motor drive circuit for intelligent knob touch control includes a motor control chip. The eighteenth pin of the motor control chip is electrically connected to a capacitor C46. An electrolytic capacitor EC5 and a capacitor C47 are connected in parallel with C46. The thirty-third pin of the motor control chip is electrically connected to an inductor FB3. A capacitor C50 is connected between inductor FB3 and the thirty-third pin. A capacitor C48 is connected in parallel with C50. Inductor FB3 is electrically connected to a capacitor C51. The thirty-fifth pin of the motor control chip is electrically connected to a capacitor C53. A capacitor C53 is connected in parallel with a capacitor C52. The first pin of the motor control chip is electrically connected to a resistor R88. A resistor R85 is connected between resistor R88 and the first pin. The second pin of the motor control chip is electrically connected to a resistor R89. A resistor R86 is electrically connected between the second and third pins. A capacitor C56 is electrically connected to the thirty-sixth pin of the motor control chip. A capacitor C54 is connected in parallel with the capacitor C56. A capacitor C49 is electrically connected to the fifteenth pin of the motor control chip. A resistor R87 is electrically connected to the thirtieth pin of the motor control chip. A capacitor C57 is electrically connected to the resistor R87. A resistor R91 is electrically connected to the twenty-first pin of the motor control chip. A capacitor C58 is electrically connected to the resistor R91. A resistor R95 is electrically connected to the twenty-fifth pin of the motor control chip. A capacitor C59 is electrically connected to the resistor R95. A capacitor C60 is electrically connected to the thirty-seventh pin of the motor control chip. A capacitor C55 is electrically connected to the seventeenth pin of the motor control chip. A resistor R97 is electrically connected to the twenty-third pin of the motor control chip. A resistor R97 is electrically connected to a resistor R96.

[0018] Preferably, the fifth pin of the motor control chip is electrically connected to a resistor R90, the sixth pin of the motor control chip is electrically connected to a resistor R92, the seventh pin of the motor control chip is electrically connected to a resistor R93, and the eighth pin of the motor control chip is electrically connected to a resistor R94.

[0019] Preferably, the motor control chip model is FU6881Q1, which integrates an MCU, a MOS driver, and a half-bridge. The chip also includes an operational amplifier, a comparator, a built-in high-voltage LDO, and a LIN module, among which the LIN module supports multi-slave automatic addressing function at various baud rates.

[0020] Preferably, capacitor C46 is grounded, capacitor C50 is grounded, capacitor C51 is grounded, capacitor C53 is grounded, and capacitor C56 is grounded.

[0021] Preferably, capacitor C46 is grounded, capacitor C60 is grounded, and resistor R97 is grounded.

[0022] Among them, capacitors C57, C58, and C59 serve as port electrostatic protection, and their specific parameters are adjusted according to the motor power; resistors R97, R96, and capacitor C60 serve as bus current sampling (single resistor), and their specific parameters are adjusted according to the motor power; capacitors C55 and C49 serve as external capacitors for the built-in charge pump, and their specific parameters are adjusted according to the motor power; capacitors C52, C53, C54, and C56 serve as external capacitors for the built-in voltage regulator circuit, and their specific parameters are adjusted according to the motor power. Power is adjusted; resistors R88, R89, R90, R92, R93, and R94 improve resistance for electrical compatibility testing (radiated emissions), and their specific parameters are adjusted according to the motor power; capacitors C51, FB3, C48, and C50 provide π-type filtering for the chip's logic power supply, and their specific parameters are adjusted according to the harmonic bandwidth; electrolytic capacitors EC5, C46, ​​and C47 stabilize and filter the chip's driver power supply, and their specific parameters are adjusted according to the ripple index.

[0023] The present invention also provides an analysis method for the above-mentioned brushless DC motor drive circuit for intelligent knob tactile control, comprising the following steps: S1. Torque analysis of intelligent knob tactile control; S2. Determination of the tactile curve function of the intelligent knob; S3. Control process and model of brushless DC motor; Operational analysis of S4, CLARKE, and PARK; S5, Operational analysis of anti-CLARKE and anti-PARK; Analysis of S6 and SVPWM operations.

[0024] It should be noted that the intelligent knob structure includes an operation knob, a reduction gear structure that is connected to the operation knob for transmission, a main control circuit board, a Hall sensor circuit board, and a brushless DC motor.

[0025] Among them, the torque analysis for the tactile control of the smart knob: The torque force of an electric motor comes from the Ampere force. For example, in a brushless DC motor, the Ampere force of a certain winding coil is F=BIL. B is the magnetic field induction intensity of the internal permanent magnet. I is the current flowing through the coil, and L is the inductance of the coil.

[0026] The torque of a motor is given by: T = F * r, where r is the torque radius. Therefore, the current in the controlled coil can generate a controlled force.

[0027] Now apply the following expression: ∅1=B*▲S, where ∅1 is the magnetic flux generated by the permanent magnet inside the motor, ▲S is the cross-sectional area of ​​the interaction between the permanent magnet and the coil, and B is the magnetic field induction intensity of the internal permanent magnet.

[0028] ∅2=IL, where ∅2 is the magnetic flux generated by the winding coil, I is the current flowing through the coil, and L is the inductance of the coil.

[0029] The motor torque can then be expressed as: T = ∅1 × ∅2 / ▲S, |T| = 1 / ▲S|∅1 × ∅2| = 1 / ▲S|∅1| * |∅2| sinθ; where θ is the angle between ∅1 and ∅2.

[0030] To obtain the maximum torque force, when |T|=|T|max, θ=90°.

[0031] Therefore, the torque force is maximized when the direction of the magnetic flux generated by the coil is perpendicular to the magnetic flux generated by the permanent magnet.

[0032] Determining the tactile feedback curve function of the smart knob: For example, the feel requirement curve for a certain product is as follows: Figure 2 As shown, the curve is not an elementary function that can be directly expressed. Therefore, it is necessary to discretize the curve and then synthesize a function that can be expressed: T=f(θ). The relationship of f can be obtained by using the Fourier series method or the approximation method.

[0033] Here's a brief explanation of the Fourier series method. When the knob rotates, T = f(θ) is clearly a periodic function of θ. Graphically, it also satisfies the Dirichlet condition. Therefore, T = f(θ) can be expressed as a Fourier series: f(\theta) = \frac{a_0}{2} + \sum_{n=1}^{\infty} A_n \cdot \cos(n\omega_0 t + \varnothing_n); Therefore, the original curve can be synthesized by adding a certain number of cosine quantities to the DC quantity.

[0034] For the control process and model of brushless DC motors: like Figure 3 As shown, this is a vector control closed-loop system for a permanent magnet synchronous motor (or brushless DC motor). Through angle sensors, coordinate transformation, and SVPWM modulation, it achieves precise control of the motor torque. The core is to convert the target torque curve into voltage control commands for the motor.

[0035] Signal flow and functional decomposition 1. Current sampling and coordinate transformation (feedback path) The three-phase currents Ia, Ib, and Ic are collected from the three-phase half-bridge output terminal of the motor, and ia-ib is calculated using the constraint condition ia+ib+ic=0.

[0036] The Clarke transformation converts the currents Ia, Ib, and Ic in the three-phase stationary coordinate system into the currents Iα and Iβ in the two-phase stationary coordinate system.

[0037] After PARK transformation, combined with the motor rotor angle θ fed back by the angle sensor, Iα and Iβ are converted into direct-axis current Id and quadrature-axis current Iq in the rotating coordinate system.

[0038] 2. Torque Controller (Core Calculation) The controller receives Id, Iq, and angle θ, and outputs the target voltage commands Ud and Uq in the rotating coordinate system. Quadrature-axis voltage: Uq = K( (f(θ)) / BL - Iq ), where f(θ) is the target torque curve, BL is the motor parameter, and K is the controller gain.

[0039] Direct-axis voltage: Ud = (0 - Id), achieving the control objective of zero direct-axis current (maximum torque current ratio control).

[0040] 3. Inverse coordinate transformation and PWM modulation (drive path) Reverse PARK transformation: Convert the voltage commands Ud and Uq in the rotating coordinate system, combined with the angle θ, into voltages Uα and Uβ in the two-phase stationary coordinate system.

[0041] Reverse Clarke Transformation: Converts Uα and Uβ into voltage commands Ua, Ub, and Uc in a three-phase stationary coordinate system.

[0042] SVPWM (Space Vector Pulse Width Modulation): Generates PWM waves based on three-phase voltage commands, drives three half-bridge output circuits, and ultimately controls the motor operation.

[0043] 4. Angle Feedback An angle sensor detects the motor rotor angle θ in real time and provides it to the PARK conversion and reverse PARK conversion modules to achieve closed-loop control.

[0044] Core features By adopting a vector control strategy with Id=0, the motor torque is ensured to be proportional to the quadrature axis current Iq, which simplifies torque control.

[0045] The target torque curve f(θ) obtained by Fourier series or approximation method is directly embedded into the controller, realizing nonlinear torque output that meets the product feel requirements.

[0046] The entire system transforms the complex three-phase AC control into a more manageable DC rotating coordinate system control through coordinate transformation, thereby improving control accuracy and dynamic response.

[0047] SVPWM operation analysis: The main idea of ​​SVPWM is to use the switching of the inverter's space voltage vector to obtain a quasi-circular rotating magnetic field. This technology can significantly reduce the harmonic components of the inverter's output current, the harmonic losses of the motor, and torque ripple, and has high voltage utilization.

[0048] The principle of SVPWM is that the space voltage vector within an arbitrary vector hexagon can be represented by the sum of two adjacent vectors.

[0049] like Figure 6-7 As shown, UOUT is the desired space voltage vector located between U60 and U0. According to the principle of equal impulse, during the very short PWM period Ts, the voltage vector resulting from the combined effect of the output time 2*T1 of U0 and the output time 2*T2 of U60 is equivalent to their vector sum, UOUT. The remaining time is filled with a zero vector, T0.

[0050] 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 brushless DC motor drive circuit for intelligent rotary knob tactile control, comprising a motor control chip, characterized in that, The motor control chip's pin 18 is electrically connected to capacitor C46. Electrolytic capacitor EC5 is connected in parallel with capacitor C46, ​​and capacitor C47 is also connected in parallel with C46. The motor control chip's pin 33 is electrically connected to inductor FB3. Capacitor C50 is connected between inductor FB3 and pin 33. Capacitor C50 is connected in parallel with capacitor C48. Inductor FB3 is electrically connected to capacitor C51. The motor control chip's pin 35 is electrically connected to capacitor C53. Capacitor C53 is connected in parallel with capacitor C52. The motor control chip's pin 1 is electrically connected to resistor R88. Resistor R85 is connected between resistor R88 and pin 1. The motor control chip's pin 2 is electrically connected to resistor R89. Resistor R86 is connected between resistor R89 ​​and pin 2. The motor control chip's 36th pin is electrically connected to capacitor C56, and capacitor C54 is connected in parallel with capacitor C56. The motor control chip's 15th pin is electrically connected to capacitor C49. The motor control chip's 30th pin is electrically connected to resistor R87, and resistor R87 is electrically connected to capacitor C57. The motor control chip's 21st pin is electrically connected to resistor R91, and resistor R91 is electrically connected to capacitor C58. The motor control chip's 25th pin is electrically connected to resistor R95, and resistor R95 is electrically connected to capacitor C59. The motor control chip's 37th pin is electrically connected to capacitor C60. The motor control chip's 17th pin is electrically connected to capacitor C55. The motor control chip's 23rd pin is electrically connected to resistor R97, and resistor R97 is electrically connected to resistor R96.

2. The brushless DC motor drive circuit for intelligent knob tactile control according to claim 1, characterized in that, The fifth pin of the motor control chip is electrically connected to a resistor R90, the sixth pin of the motor control chip is electrically connected to a resistor R92, the seventh pin of the motor control chip is electrically connected to a resistor R93, and the eighth pin of the motor control chip is electrically connected to a resistor R94.

3. A brushless DC motor drive circuit for intelligent knob tactile control according to claim 1 or 2, characterized in that, The motor control chip model is FU6881Q1. The chip integrates an MCU, a MOS driver, a half-bridge, an operational amplifier, a comparator, a built-in high-voltage LDO, and a LIN.

4. The brushless DC motor drive circuit for intelligent knob tactile control according to claim 3, characterized in that, Capacitor C46 is grounded, capacitor C50 is grounded, capacitor C51 is grounded, capacitor C53 is grounded, and capacitor C56 is grounded.

5. A brushless DC motor drive circuit for intelligent knob tactile control according to claim 4, characterized in that, Capacitor C46 is grounded, capacitor C60 is grounded, and resistor R97 is grounded.

6. An analysis method for a brushless DC motor drive circuit for intelligent knob tactile control as described in claim 1, characterized in that, Includes the following steps: S1. Torque analysis of intelligent knob tactile control; S2. Determination of the tactile curve function of the intelligent knob; S3. Control process and model of brushless DC motor; Operational analysis of S4, CLARKE, and PARK; S5, Operational analysis of anti-CLARKE and anti-PARK; Analysis of S6 and SVPWM operations.

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