CN114977901A

CN114977901A - Linear resonant motor driving method and system

Info

Publication number: CN114977901A
Application number: CN202210626770.1A
Authority: CN
Inventors: 石宏霄; 钱舜; 何秀安; 史浩凯; 王军强; 刘岩海; 蒋崇瀚
Original assignee: Shanghai Fourier Semiconductor Co ltd
Current assignee: Shanghai Fourier Semiconductor Co ltd
Priority date: 2022-04-01
Filing date: 2022-06-05
Publication date: 2022-08-30

Abstract

The embodiment of the invention provides a linear resonant motor driving method and system, the linear resonant motor is driven based on IV detection, the driving voltage V and the driving current I of the linear resonant motor can be detected in real time under the condition of not stopping a driving circuit, and the back electromotive force and the coil impedance of the linear resonant motor are estimated in real time by using an adaptive Sliding mode adaptive Observer (Sliding mode Observer) or an adaptive Longberg adaptive Observer (Luenberger Observer), so that the resistance value R of a motor coil is realized _T And real-time estimation of the induced electromotive force BEMF, improved F0 tracking and LRA amplitude controlAnd (4) precision.

Description

Linear resonant motor driving method and system

Technical Field

The embodiment of the invention relates to the technical field of linear resonant motor driving, in particular to a linear resonant motor driving method and system.

Background

A Linear resonant motor (LRA) is generally used to provide a haptic feedback effect on a portable terminal. The LRA includes constituent components such as a spring, a coil, and a vibrator. The drive is provided by an LRA drive chip. The driving chip applies exciting current to the coil to generate a magnetic field, and pushes the vibrator with magnetism to move towards a certain direction. When the direction of the exciting current is changed, the magnetic field and the driving force are also changed. Therefore, if a periodic voltage signal is applied to the coil by the driving chip, the generated periodic exciting current pushes the vibrator to vibrate back and forth, and the effect of tactile feedback is achieved. Due to the resonance characteristic of the LRA, the amplitude of the vibrator vibration shows a band-pass characteristic along with the frequency of the driving signal, and when the frequency of the driving signal is at the natural frequency (F0) of the vibrator, the amplitude of the vibrator vibration reaches the highest, and the vibration efficiency is optimal.

The existing LRA driving device technology includes F0 calibration technology and windowing F0 tracking technology, F0 tracking based on IV detection, and amplitude closed-loop control technology.

The F0 calibration technique turns off the driving signal in the middle of providing the driving voltage waveform through the driving chip, so that the LRA oscillator freely oscillates for a plurality of cycles, and the acquisition circuit is used to acquire the induced electromotive force waveform (Back electromagnetic flux, BEMF) generated when the oscillator itself oscillates. The induced electromotive force waveform is a damping oscillation waveform, the damping oscillation frequency of the LRA is calculated by detecting the zero crossing point interval of the induced electromotive force waveform, and the sampling frequency of the driving voltage waveform is adjusted according to the difference value of the damping oscillation frequency and the frequency of the standard driving voltage waveform, so that the frequency of the driving voltage waveform is consistent with the inherent frequency of the LRA, and the effects of improving the vibration amplitude and the efficiency are achieved.

The windowing F0 tracking technique detects BEMF generated by LRA oscillator motion by the driver chip turning off the drive signal in a short time window around the zero crossing of the supplied drive voltage waveform. When the vibrator speed is switched from positive to negative, the corresponding BEMF is also switched from positive to negative. Therefore, after the BEMF detection circuit detects the BEMF zero-crossing point, the LRA driving circuit is turned on again, and a driving voltage waveform with the negative direction is generated, wherein the length of the driving voltage waveform is determined by the current BEMF zero-crossing point and the last BEMF zero-crossing point interval. By the method, the effects that the driving voltage and the vibrator speed are the same in direction, and the zero crossing point of the driving waveform and the zero crossing point of the BEMF are aligned in time can be achieved. Since the driving voltage waveform and the vibrator speed are always in phase, the frequency of the driving signal is always tracked on F0 of the vibrator according to the phase-frequency characteristic of the linear resonance system, and therefore the F0 tracking effect is achieved.

The formula of E ═ V-I · R used by the F0 tracking based IV detection and closed loop control techniques for LRA amplitude assumes that the motor's coil resistance value R is a known quantity. After the coil resistance R is measured through power-on calibration, the coil resistance R is considered as a constant value, and the situation that the coil resistance R is increased under the condition that the environment temperature changes or the motor coil is heated by exciting current for a long time is not considered. Since the coil resistance value changes slowly and cannot be known in real time by measurement, the calculation formula of E ═ V · R has an error, and the accuracy of F0 tracking and LRA amplitude detection deteriorates.

Disclosure of Invention

Therefore, embodiments of the present invention provide a method and a system for driving a linear resonant motor to solve the above technical problems in the prior art.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

according to a first aspect of an embodiment of the present invention, there is provided a linear resonant motor driving method, including:

detecting a driving voltage V and a driving current I of the linear resonant motor in real time under the condition of not stopping driving;

predicting back electromotive force and coil impedance R in the motor working process by using the driving voltage V and the driving current I _T ；

Calculating the difference between the input amplitude and the predicted back electromotive force to obtain an error signal;

comparing the phase difference between the predicted back electromotive force and the current driving voltage waveform to obtain a phase difference comparison result;

generating a periodic signal with variable amplitude and frequency, adjusting the amplitude of the periodic signal by using the error signal, and adjusting the frequency of the periodic signal by using the phase difference comparison result;

generating a PWM signal using the periodic signal;

and converting the PWM signal into a voltage signal to drive the linear resonant motor.

Further, the driving voltage V and the driving current I are used for predicting the back electromotive force and the coil impedance R in the working process of the motor _T The method comprises the following steps:

initial estimation value based on set exciting current

Obtaining a first inverse number of a resistance voltage drop initial estimated value and a reverse electromotive force initial estimated value of a motor coil;

using the drive voltage V (t) at the first moment ₁ ) Calculating an excitation current estimated value at a first moment by the first inverse number and the initial estimated value of the resistance voltage drop of the motor coil

Using the drive current I (t) at a first instant ₁ ) And an estimated value of the excitation current

Calculating a motor coil resistance estimate at a first time

And a second inverse of the back EMF estimate, the motor coil resistance estimate at the first time

For the predicted coil impedance R at the first moment _T ；

Calculating a motor coil resistance estimate at a first time

And an estimated value of the exciting current

Obtaining the estimated value of the resistance voltage drop of the motor coil at the first moment;

combining the second inverse number calculated based on the previous moment and the estimated value of the resistance voltage drop of the motor coil with the driving voltage V (t) of the current moment _n ) To obtain the estimated value of the exciting current at each subsequent time

Using the drive current I (t) at subsequent respective instants _n ) And an estimated value of the excitation current

Calculating the resistance estimated value of the motor coil at each subsequent time

And a second inverse of the back EMF estimate, the motor coil resistance estimate at each subsequent time

For the predicted coil impedance R at subsequent respective times _T ；

And an estimated value of the exciting current

Obtaining the estimated value of the resistance voltage drop of the motor coil at each subsequent moment by the second product;

calculating a first product of the second inverse number and-1 at each time instant; and

and filtering out the ripple waves generated by shaking of the adaptive observer based on the first product to obtain and output a back electromotive force estimated value at each moment, wherein the back electromotive force estimated value is the predicted back electromotive force.

Further, adjusting the amplitude of the periodic signal with the error signal includes:

comparing the magnitude of the error signal with a 0 value;

if the error signal is less than 0, increasing the amplitude of the periodic signal;

if the error signal is greater than 0, the amplitude of the periodic signal is reduced.

Further, the method further comprises:

judging whether the amplitude of the periodic signal reaches the maximum driving voltage allowed by the linear resonant motor or not;

and if the amplitude of the periodic signal reaches the maximum driving voltage allowed by the linear resonant motor, driving the linear resonant motor by using a maximum driving voltage signal.

Further, adjusting the frequency of the periodic signal using the phase difference comparison result includes:

if the predicted phase of the back electromotive force lags behind the phase of the current driving voltage waveform, reducing the frequency of the periodic signal;

and if the phase of the predicted back electromotive force is ahead of the phase of the current driving voltage waveform, increasing the frequency of the periodic signal.

Preferably, the method further comprises:

judging whether the predicted back electromotive force is larger than a preset rated back electromotive force threshold value or not;

if the predicted back electromotive force is larger than a preset rated back electromotive force threshold value, triggering amplitude protection and stopping a driving circuit;

if the predicted back electromotive force is not larger than the preset rated back electromotive force threshold value, the amplitude protection is not triggered, and the driving circuit is not stopped.

Preferably, the method further comprises:

generating a first amplitude input attenuation coefficient;

calculating a first product of the first amplitude input attenuation coefficient and the input amplitude to obtain an adjusted input amplitude;

calculating the difference value between the adjusted input amplitude and the predicted back electromotive force to obtain an error signal;

wherein the first amplitude input attenuation coefficient is greater than 0 and less than or equal to 1;

judging whether the predicted back electromotive force peak value is higher than a first back electromotive force preset threshold value Vth 1;

if the predicted peak value of the back electromotive force is higher than the first back electromotive force preset threshold Vth1, determining whether a first duration of the predicted peak value of the back electromotive force higher than the first back electromotive force preset threshold Vth1 reaches a first preset time t ₁ ；

If the first duration reaches the first preset time t ₁ Decreasing the first amplitude input attenuation factor;

judging whether the predicted back electromotive force peak value is smaller than a second back electromotive force preset threshold value Vth 2;

if the predicted back electromotive force peak value is smallAt the second bemf preset threshold Vth2, it is determined whether the second duration of the predicted bemf peak value smaller than the second bemf preset threshold Vth2 reaches the second preset time t ₂ ；

If the second duration reaches the second preset time t ₂ And decreasing the first amplitude input attenuation factor.

Preferably, the method further comprises:

coil impedance R based on prediction _T Calculating the temperature T of the motor coil by using a temperature calculation formula, wherein the temperature calculation formula comprises the following steps:

wherein R is ₂₅ Is the coil impedance at 25 ℃, T _coef Is the temperature coefficient of the motor coil;

judging whether the temperature T of the motor coil exceeds a preset temperature protection threshold value or not;

if the temperature T of the motor coil exceeds a preset temperature protection threshold value, triggering temperature protection and stopping a driving circuit;

judging whether the temperature T of the motor coil is smaller than a preset temperature protection release threshold value or not;

and if the temperature T of the motor coil is less than a preset temperature protection release threshold value, restoring the driving circuit.

Preferably, the method further comprises:

generating a second amplitude input attenuation coefficient;

calculating a second product of the second amplitude input attenuation coefficient and the input amplitude to obtain an adjusted input amplitude;

wherein the second amplitude input attenuation coefficient is greater than 0 and less than or equal to 1;

judging whether the temperature T of the motor coil is higher than a first temperature preset threshold value or notT ₁ ；

If the temperature T of the motor coil is higher than a first temperature preset threshold T ₁ If so, judging that the temperature T of the motor coil is higher than a first preset temperature threshold T ₁ Whether the third duration of time of (2) reaches the third preset time t ₃ ；

If the third duration reaches the third preset time t ₃ Decreasing the second amplitude input attenuation factor;

judging whether the temperature T of the motor coil is less than a second preset temperature threshold T or not ₂ ；

If the motor coil temperature T is less than a second temperature preset threshold T ₂ If so, judging that the temperature T of the motor coil is less than a second preset temperature threshold T ₂ Whether the fourth duration reaches the fourth preset time t ₄ ；

If the fourth duration reaches the fourth preset time t ₄ And increasing the first amplitude input attenuation coefficient.

According to a second aspect of embodiments of the present invention, there is provided a linear resonant motor drive system, the system including:

an analog circuit portion and a digital circuit portion, the analog circuit portion comprising: the device comprises a current detection ADC, a voltage detection ADC and a drive circuit; the digital circuit part includes: the device comprises an adaptive observer with parameter identification, a driving voltage controller, an F0 detection module, a driving waveform DDS and a PWM modulator;

the current detection ADC is used for detecting the driving voltage V of the linear resonant motor in real time under the condition of not stopping driving;

the voltage detection ADC is used for detecting the driving current I of the linear resonant motor in real time under the condition of not stopping driving;

the adaptive observer is used for predicting the back electromotive force and the coil impedance R in the working process of the motor by using the driving voltage V and the driving current I _T ；

The driving voltage controller is used for calculating the difference between the input amplitude and the predicted back electromotive force to obtain an error signal;

the F0 detection module is used for comparing the phase difference between the predicted back electromotive force and the current driving voltage waveform to obtain a phase difference comparison result;

the driving waveform DDS is used for generating a periodic signal with variable amplitude and frequency, the amplitude of the periodic signal is adjusted by using the error signal, and the frequency of the periodic signal is adjusted by using the phase difference comparison result;

the PWM modulator is used for generating a PWM signal by utilizing the periodic signal;

the driving circuit is used for converting the PWM signal into a voltage signal to drive the linear resonant motor.

Preferably, the digital circuit part further includes: the device comprises an amplitude protection module, a temperature calculation module and a temperature protection module;

the amplitude protection module is used for judging whether the predicted back electromotive force is larger than a preset rated back electromotive force threshold value; if the predicted back electromotive force is larger than a preset rated back electromotive force threshold value, triggering amplitude protection and stopping a driving circuit; if the predicted back electromotive force is not larger than the preset rated back electromotive force threshold value, the amplitude protection is not triggered, and the driving circuit is not stopped;

the temperature calculation module is used for obtaining coil impedance R based on prediction _T Calculating the temperature T of the motor coil by using a temperature calculation formula, wherein the temperature calculation formula comprises the following steps:

the temperature protection module is used for judging whether the temperature T of the motor coil exceeds a preset temperature protection threshold value; if the temperature T of the motor coil exceeds a preset temperature protection threshold value, triggering temperature protection and stopping a driving circuit; judging whether the temperature T of the motor coil is smaller than a preset temperature protection release threshold value or not; if the temperature T of the motor coil is less than a preset temperature protection release threshold value, the driving circuit is recovered;

preferably, the digital circuit part further includes: an amplitude control module;

the amplitude control module is used for generating a first amplitude input attenuation coefficient; calculating a first product of the first amplitude input attenuation coefficient and the input amplitude to obtain an adjusted input amplitude; and calculating the difference between the adjusted input amplitude and the predicted back electromotive force by the driving voltage controller to obtain an error signal.

Preferably, the digital circuit part further includes: a temperature control module;

the temperature control module is used for generating a second amplitude input attenuation coefficient; calculating a second product of the second amplitude input attenuation coefficient and the input amplitude to obtain an adjusted input amplitude; and calculating the difference between the adjusted input amplitude and the predicted back electromotive force by the driving voltage controller to obtain an error signal.

Compared with the prior art, the linear resonant motor driving method and system provided by the embodiment of the application can drive the linear resonant motor based on IV detection, can detect the driving voltage V and the driving current I of the linear resonant motor in real time under the condition of not stopping the driving circuit, and estimates the back electromotive force and the coil impedance of the linear resonant motor in real time by using an adaptive Sliding mode adaptive Observer (slipping mode Observer) or an adaptive luneberg adaptive Observer (Luenberger Observer), so as to realize the resistance value R of a motor coil _T And real-time estimation of the induced electromotive force BEMF, improve the accuracy of F0 tracking and LRA amplitude control.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions that the present invention can be implemented, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the effects and the achievable by the present invention, should still fall within the range that the technical contents disclosed in the present invention can cover.

Fig. 1 is a schematic structural diagram of a linear resonant motor driving system according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of a linear resonant motor driving system according to a second embodiment of the present invention;

fig. 3 is a schematic structural diagram of a linear resonant motor driving system according to a third embodiment of the present invention;

fig. 4 is a schematic flowchart of a method for driving a linear resonant motor according to an embodiment of the present invention;

FIG. 5 is a diagram illustrating the prediction of the back EMF and the coil resistance R during the operation of the motor according to an embodiment of the present invention _T A schematic flow diagram of (a);

fig. 6 is a schematic structural diagram of an adaptive observer according to an embodiment of the present invention.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

The conventional F0 calibration technology is only suitable for being performed in the process of in-line calibration and startup calibration. If the environment and the temperature of the portable device change after the portable device is started, the driving voltage waveform cannot update the frequency of the portable device so as to track the natural frequency change of the oscillator in real time. In addition, due to the non-linear characteristics introduced by the mechanical structure of the linear resonant motor, when the amplitude or load changes, the natural frequency shifts. The existing F0 calibration technology cannot solve the problem that the natural frequency of the vibrator shifts along with the change of the amplitude of the vibrator.

The traditional windowing F0 tracking technology realizes the synchronization of the driving waveform and the vibrator vibration direction by stopping the driving waveform windowing and detecting the BEMF zero crossing point. During the zero crossing point, the chip stops driving the circuit, so that additional harmonic components are caused, and the problems of high audio noise and the like are caused.

In the conventional windowing F0 tracking technology, during the zero-crossing point, since the chip stops driving the circuit tube, the amplitude of the finally generated average driving signal is reduced along with the increase of the zero-crossing windowing time, and an additional compensation algorithm is needed to adjust the output amplitude so as to meet the requirement of the vibration amplitude consistency.

In the conventional windowing F0 tracking technology, during a zero-crossing point, because a chip stops driving a circuit, the amplitude of a finally generated average driving signal is reduced along with the increase of zero-crossing windowing time, so that the amplitude of a maximum average driving signal under a rated power supply voltage is reduced.

In the existing windowing F0 tracking technology, during a zero crossing point, because a chip stops driving a circuit, but current on a parasitic inductance of a motor coil cannot change suddenly, and the inductance continues current, a parasitic diode of a chip output power tube is conducted, and output end BEMF detection is influenced. Therefore, additional waiting for parasitic inductance discharge is required before detecting BEMF, increasing zero-crossing latency. In order to avoid the reliability problems caused by the conduction of the parasitic diode of the chip output power tube and the substrate de-bias, an additional discharge circuit needs to be designed or the device interval needs to be increased, so that the additional chip cost is increased.

The formula for E ═ V-I · R used by the F0 tracking based IV detection and closed loop control technique for LRA amplitude assumes that the motor's coil resistance value R is a known quantity. After the coil resistance R is measured through power-on calibration, the coil resistance R is considered as a constant value, and the situation that the coil resistance R is increased under the condition that the environment temperature changes or the motor coil is heated by exciting current for a long time is not considered. Since the coil resistance value changes slowly and cannot be known in real time by measurement, the calculation formula of E ═ V-I · R has an error, and the accuracy of F0 tracking and LRA amplitude detection deteriorates.

In addition, all the above techniques cannot measure the temperature of the motor coil at present, and cannot realize the over-temperature protection function of the LRA in a long-time and high-power state.

Referring to fig. 1, a first embodiment of the present application provides a linear resonant motor driving system including: an analog circuit part 1 and a digital circuit part 2, the analog circuit part 1 including: a current detection adc (analog to Digital converter)11, a voltage detection adc (analog to Digital converter)12, and a driving circuit 13; the digital circuit portion 2 includes: an adaptive observer 21 with parameter identification, a driving voltage controller 22, an F0 detection module 23, a driving waveform dds (direct Digital synthesizer)24, and a pwm (pulse width modulation) modulator 25.

Specifically, the current detection ADC 11 is used to detect the drive voltage V of the linear resonant motor 3 in real time without stopping the drive; the voltage detection ADC 12 is configured to detect the driving current I of the linear resonant motor 3 in real time without stopping driving; the adaptive observer 21 is used for predicting the back electromotive force and the coil impedance R during the operation of the motor by using the driving voltage V and the driving current I _T (ii) a The driving voltage controller 22 is configured to calculate a difference between the input amplitude and the predicted back electromotive force to obtain an error signal; the F0 detection module 23 is configured to compare the phase difference between the predicted back electromotive force and the current driving voltage waveform to obtain a phase difference comparison result; the driving waveform DDS 24 is used for generating a periodic signal with variable amplitude and frequency, the amplitude of the periodic signal is adjusted by using an error signal, and the frequency of the periodic signal is adjusted by using a phase difference comparison result; the PWM modulator 25 is configured to generate a PWM signal using the periodic signal; the driving circuit 13 is used for driving the linear resonant motor 3 by converting the PWM signal into a voltage signal.

Further, the digital circuit section 2 further includes: the amplitude protection module 26, the amplitude protection module 26 is configured to determine whether the predicted back electromotive force is greater than a preset rated back electromotive force threshold; if the predicted back electromotive force is larger than a preset rated back electromotive force threshold value, triggering amplitude protection and stopping the driving circuit 3; if the predicted back electromotive force is not greater than the preset rated back electromotive force threshold, the amplitude protection is not triggered, and the driving circuit 3 is not stopped.

During operation of the linear resonant motor, the coils thereof generate heat due to the application of the exciting current. If the coil generates heat for a long time and cannot be timely diffused, high temperature can be generated inside the LRA, so that the amplitude control precision of the oscillator is poor, noise occurs, and even permanent damage occurs.

Further, the digital circuit section 2 further includes: a temperature calculation module 27 and a temperature protection module 28; the temperature calculation module 27 is used for calculating the coil impedance R based on the prediction _T Calculating the temperature T of the motor coil by using a temperature calculation formula, wherein the temperature calculation formula comprises the following steps:

wherein R is ₂₅ Is the coil impedance at 25 ℃, T _coef Is the temperature coefficient of the motor coil. The temperature protection module 28 is configured to determine whether the temperature T of the motor coil exceeds a preset temperature protection threshold; if the temperature T of the motor coil exceeds a preset temperature protection threshold value, triggering temperature protection and stopping the driving circuit 3; judging whether the temperature T of the motor coil is less than a preset temperature protection release threshold value or not; and if the temperature T of the motor coil is less than the preset temperature protection release threshold value, the driving circuit 3 is recovered.

The linear resonant motor driving system disclosed in the embodiment of the invention simultaneously comprises the functions of amplitude protection and temperature protection. In the embodiment of the invention, when the temperature T of the motor coil is detected to exceed the preset temperature protection threshold, the temperature protection function of the motor coil is triggered, and the driving circuit is closed, so that the motor is prevented from abnormal function or permanent damage due to over-temperature.

Referring to fig. 2, a second embodiment of the present application provides a linear resonant motor driving system, which, as such, includes: an analog circuit part 1 and a digital circuit part 2, the analog circuit part 1 including: a current detection ADC 11, a voltage detection ADC 12, and a drive circuit 13; the digital circuit portion 2 includes: the device comprises an adaptive observer 21 with parameter identification, a driving voltage controller 22, an F0 detection module 23, a driving waveform DDS 24 and a PWM modulator 25.

Further, the digital circuit section 2 further includes: an amplitude control module 29; the amplitude control module 29 is used for generating a first amplitude input attenuation coefficient; calculating a first product of a first amplitude input attenuation coefficient and the input amplitude to obtain an adjusted input amplitude; the difference between the adjusted input amplitude and the predicted back emf is calculated by the drive voltage controller 22 to obtain an error signal.

Further, the digital circuit section 2 further includes: a temperature calculation module 27 and a temperature protection module 28; the temperature calculation module 27 is used for calculating the coil resistance R based on the prediction _T Calculating the temperature T of the motor coil by using a temperature calculation formula, wherein the temperature calculation formula comprises the following steps:

The linear resonant motor driving system disclosed in the embodiment of the invention simultaneously comprises the functions of amplitude control and temperature protection. In the embodiment of the invention, when the temperature T of the motor coil is detected to exceed the preset temperature protection threshold, the temperature protection function of the motor coil is triggered, and the driving circuit is closed, so that the motor is prevented from abnormal function or permanent damage due to over-temperature.

Referring to fig. 3, a third embodiment of the present application provides a linear resonant motor driving system, including: an analog circuit part 1 and a digital circuit part 2, the analog circuit part 1 including: a current detection ADC 11, a voltage detection ADC 12, and a drive circuit 13; the digital circuit portion 2 includes: the device comprises an adaptive observer 21 with parameter identification, a driving voltage controller 22, an F0 detection module 23, a driving waveform DDS 24 and a PWM modulator 25.

Specifically, the current detection ADC 11 is used to detect the drive voltage V of the linear resonant motor 3 in real time without stopping the drive; the voltage detection ADC 12 is configured to detect the driving current I of the linear resonant motor 3 in real time without stopping driving; the adaptive observer 21 is used for utilizing driving powerVoltage V and drive current I, predicting back electromotive force and coil impedance R in motor operation _T (ii) a The driving voltage controller 22 is configured to calculate a difference between the input amplitude and the predicted back electromotive force to obtain an error signal; the F0 detection module 23 is configured to compare the phase difference between the predicted back electromotive force and the current driving voltage waveform to obtain a phase difference comparison result; the driving waveform DDS 24 is used for generating a periodic signal with variable amplitude and frequency, the amplitude of the periodic signal is adjusted by using an error signal, and the frequency of the periodic signal is adjusted by using a phase difference comparison result; the PWM modulator 25 is configured to generate a PWM signal using the periodic signal; the driving circuit 13 is used for driving the linear resonant motor 3 by converting the PWM signal into a voltage signal.

Further, the digital circuit section 2 further includes: a temperature calculation module 27, a temperature control module 210; the temperature calculation module 27 is used for calculating the coil resistance R based on the prediction _T Calculating the temperature T of the motor coil by using a temperature calculation formula, wherein the temperature calculation formula comprises the following steps:

wherein R is ₂₅ Is the coil impedance at 25 ℃, T _coef Is a coil of a motorTemperature coefficient. The temperature control module 210 is configured to generate a second amplitude input attenuation factor; calculating a second product of a second amplitude input attenuation coefficient and the input amplitude to obtain an adjusted input amplitude; the difference between the adjusted input amplitude and the predicted back emf is calculated by the drive voltage controller 22 to obtain an error signal.

Therefore, the linear resonant motor driving system disclosed in the embodiment of the invention simultaneously comprises the functions of amplitude protection and temperature control.

Further, referring to fig. 6, in the embodiment of the present application, as described above, in the case where the driving of the linear resonant motor driving circuit 1 is not interrupted, the voltage detection ADC 11 detects the voltage waveform across the linear resonant motor 3, and the current detection ADC 12 detects the current waveform flowing through the linear resonant motor 3.

Referring to fig. 6, the relationship between the driving voltage and the driving current of the linear resonant motor 3 can be described by an IV characteristic model of the linear resonant motor. The input signal of the IV characteristic model of the linear resonant motor is the drive voltage V of the linear resonant motor. The output signal of the IV characteristic model of the linear resonant motor is the drive current I of the linear resonant motor. The transfer function of the IV characteristic model of the linear resonant motor is the admittance (I/V) of the linear resonant motor. Due to the resonant characteristics of the linear resonant motor, the linear resonant motor vibration amplitude and vibration rate reach a maximum at its natural frequency. The back electromotive force of the linear resonant motor is proportional to the vibration rate of the linear resonant motor, and thus the back electromotive force also reaches a maximum value at its natural frequency. From the formula BEMF ═ V-I · R, the output of the linear resonant motor IV characteristic model (drive current I) reaches a minimum value at the natural frequency under the condition that the amplitude of the input drive voltage V is constant, and therefore, the linear resonant motor IV characteristic model exhibits a trap-like band stop characteristic.

Further, referring to fig. 6, the adaptive observer 21 includes: the device comprises a hybrid operator 210, a first amplifier 211, an integrator 212, a two-input subtractor 213, a parameter identification module 214, a multiplier 215, an observation unit 216, a second amplifier 217, a third amplifier 218 and a low-pass filter 219.

In the embodiment of the present invention, the preset parameters of the adaptive observer 21 include: the coil inductance L of a linear resonant motor is a known quantity, supplied by the LRA manufacturer, or can be measured by an impedance tester, typically 100 uH. Adaptive sliding mode adaptive observer gain K or adaptive Luenberg adaptive observer gain L _d It is a predetermined positive real number. The iteration coefficient alpha of the parameter identification module is a preset positive real number. The bandwidth, order, etc. of the low-pass filter are typically 500Hz and 4 order.

Specifically, an initial estimation value of the excitation current is calculated by the multiplier 215

With a predetermined initial estimate of the resistance of the motor coil

Obtaining an initial estimated value of the resistance-voltage drop of the motor coil; the initial driving current I (t0) and the initial estimation value of the exciting current are calculated by the two-input subtracter 213

To obtain an initial error of the excitation current estimation

Estimating initial error of exciting current by observation unit 216 by using gain K of adaptive sliding mode observer or gain Ld of adaptive Luenberger observer

Carrying out treatment; calculating the product of the processed excitation current estimation initial error and the second gain L through a second amplifier 217 to obtain a first inverse number of the back electromotive force initial estimation value; the driving voltage V (t) at the first time is converted by the hybrid arithmetic unit 210 ₁ ) And taking the first inverse number as a positive input, taking the initial estimated value of the resistance voltage drop of the motor coil as a negative input, and carrying out addition and subtraction mixed operation to obtain the excitation of the motor coil generated at the first momentA magnetic voltage estimate; the product of the excitation voltage estimated value at the first moment and the first gain 1/L is calculated by the first amplifier 211 to obtain the excitation current change rate estimated value at the first moment

Using the field current rate of change estimate at the first time by integrator 212

Performing integral operation to obtain an excitation current estimated value at a first moment

The two-input subtractor 213 calculates the drive current I (t) at the first time ₁ ) And an estimated value of the exciting current

To obtain an excitation current estimation error at the first moment

The estimated value of the excitation current at the first time is utilized by the parameter identification module 214

And excitation current estimation error

Iterative calculation is carried out, the resistance of the motor coil is detected to change along with external factors, and the estimated value of the resistance of the motor coil at the first moment is obtained and output

The estimated motor coil resistance value at the first time is calculated by the multiplier 215

And an estimated value of the exciting current

Obtaining the estimated value of the resistance voltage drop of the motor coil at the first moment; the observation unit 216 utilizes the adaptive sliding mode observer gain K or the adaptive Luenberger observer gain L _d Estimating an error of the field current at the first time

Carrying out treatment; the excitation current estimation error at the first time after the calculation processing by the second amplifier 217

Multiplying the second gain L to obtain a second inverse number of the estimated value of the back electromotive force at the first moment; the hybrid operator 210 is also used for converting the driving voltage V (t) at the current moment _n ) Taking the second inverse number of the previous moment as positive input, taking the resistance voltage drop estimation value of the motor coil of the previous moment as negative input, and carrying out addition and subtraction mixed operation to obtain the excitation voltage estimation value of the motor coil generated at each subsequent moment; the first amplifier 211 is further configured to calculate a product of the excitation voltage estimated value and the first gain 1/L at each subsequent time, so as to obtain an excitation current change rate estimated value at each subsequent time

Integrator 212 is also operative to utilize the field current rate of change estimates at subsequent times

Performing integral operation to obtain the estimated value of the exciting current at each subsequent time

The two-input subtractor 213 is also used to calculate the driving current I (t) at each subsequent time _n ) And an estimated value of the exciting current

To obtain the estimation error of the exciting current at each subsequent time

The parameter identification module 214 is further configured to utilize the field current estimates at subsequent times

And excitation current estimation error

Iterative calculation is carried out, the resistance of the motor coil is detected to change along with external factors, and estimated values of the resistance of the motor coil at each subsequent moment are obtained and output

Multiplier 215 is also used to calculate an estimate of the motor coil resistance at each subsequent time instant

And an estimated value of the exciting current

Obtaining the estimated value of the resistance voltage drop of the motor coil at each subsequent moment by the second product; the observation unit 216 is further configured to utilize the adaptive sliding mode observer gain K or the adaptive Luenberger observer gain L _d Estimating the error of the exciting current at each subsequent time

Carrying out treatment; the second amplifier 217 is further used for calculating the excitation current estimation error at each subsequent time instant after processing

Multiplying the second gain L to obtain a second inverse number of the back electromotive force estimated value at each subsequent moment; calculating, by the third amplifier 218, a first product of the second inverse and-1; after the ripple generated by the shake of the adaptive observer is filtered out based on the first product by the low-pass filter 219, a back electromotive force estimation value is obtained and output.

Compared with the prior art, the linear resonant motor driving system provided by the embodiment of the application drives the linear resonant motor based on the IV detection, can detect the driving voltage V and the driving current I of the linear resonant motor in real time under the condition of not stopping the driving circuit, and estimates the reverse electromotive force and the coil impedance of the linear resonant motor in real time by using an adaptive Sliding mode adaptive Observer (slipping mode Observer) or an adaptive lunberger adaptive Observer (Luenberger Observer), thereby realizing the resistance value R of a motor coil _T And real-time estimation of induced electromotive force (BEMF), the accuracy of F0 tracking and LRA amplitude control is improved. Even if R changes due to factors such as interface plugging and unplugging, environment temperature change, motor long vibration temperature rise and the like, the BEMF detection value can be detected in real time to ensure correct detection of the BEMF detection value.

Corresponding to the linear resonant motor driving system disclosed above, the embodiment of the invention also discloses a linear resonant motor driving method. A linear resonant motor driving method disclosed in an embodiment of the present invention will be described in detail below with reference to a linear resonant motor driving system described above.

As shown in fig. 4, an embodiment of the present application provides a linear resonant motor driving method specifically including the following steps.

Detecting the driving voltage V of the linear resonant motor 3 in real time by the current detection ADC 11 without stopping the driving; the drive current I of the linear resonant motor 3 is detected in real time by the voltage detection ADC 12.

The current detection ADC 11 and the voltage detection ADC 12 detect the IV characteristic of the linear resonant motor 3 in real time, specifically, the IV characteristic of the linear resonant motor 3 includes a drive voltage V and a drive current I, the drive voltage V of the linear resonant motor 3 is detected in real time by the voltage detection ADC 11 and transmitted to the adaptive observer 21 without stopping the driving, and the drive current I of the linear resonant motor 3 is detected in real time by the current detection ADC 12 and transmitted to the adaptive observer 21.

The adaptive observer 21 is used to predict the back electromotive force and the coil impedance R during the operation of the motor using the driving voltage V and the driving current I _T Referring to fig. 5 and 6, the above implementation steps are described in detail below.

The adaptive observer 21 receives the currently detected drive voltage V (t) of the linear resonant motor 3 _n ) And a drive current I (t) _n ) First, an initial estimation value of the exciting current is set

And the first inverse number of the initial estimated value of the resistance voltage drop of the motor coil and the initial estimated value of the back electromotive force is obtained as 0.

Specifically, the obtaining of the initial estimated value of the resistance-voltage drop of the motor coil includes: setting an initial estimation value of exciting current

Is 0; the multiplier 215 calculates the initial estimation value of the exciting current

With a predetermined initial estimate of the resistance of the motor coil

And obtaining an initial estimated value of the resistance-voltage drop of the motor coil.

Specifically, the detecting the first inverse of the estimated value of the back electromotive force includes: the initial driving current I (t0) and the initial estimation value of the exciting current are calculated by the two-input subtracter 213

To obtain an initial error of the excitation current estimation

The observed unit 216 utilizes the gain K of the adaptive sliding mode observer or the gain L of the adaptive Luenberger observer _d Estimating initial error for field current

Carrying out treatment; through a second amplifier217 calculates the product of the processed initial error of the excitation current estimation and the second gain L to obtain a first inverse number of the initial estimation value of the back electromotive force.

In the embodiment of the present application, the adaptive observer 21 is divided into an adaptive sliding mode adaptive observer and an adaptive lunberg adaptive observer. When the adaptive observer 21 is an adaptive sliding mode adaptive observer, the observation unit 216 estimates an initial error for the excitation current

After sgn () operation, K is multiplied and used as output, that is, the specific operation formula of the observation unit 216 is:

wherein sgn is a sign function, and K is the gain of the adaptive sliding mode adaptive observer. The larger K is, the faster the tracking speed of the sliding mode adaptive observer is, and the more stable the system is, but the more serious the shake phenomenon is at the moment. When the adaptive observer 21 is an adaptive lunberg adaptive observer, the observation unit 216 estimates the initial error directly using the excitation current

Multiplied by L _d As an output, the specific operation formula of the observation unit 216 is:

wherein L is _d For the Luenberger adaptive observer gain, L _d The larger the adaptive lunberg adaptive observer, the faster the tracking rate, but the worse the stability.

The driving voltage V (t) at the first time is utilized by the adaptive observer 21 ₁ ) The first inverse number, the initial estimated value of the resistance voltage drop of the motor coil, and the estimated value of the exciting current at the first moment

Specifically, the blending arithmetic unit 210 in the embodiment of the present invention is a three-input addition and subtraction blending arithmetic unit, which utilizes kirchhoffThe voltage law is obtained by performing circuit analysis on the coil loop of the LRA. Calculating the estimated value of the exciting current at the first moment

The method comprises the following specific steps: the drive voltage V (t) of the first time-series resonant motor 3 is detected in real time by the voltage detection ADC 11 ₁ ) The first inverse number of the initial estimation value of the back electromotive force calculated by the second amplifier 217 is sent to the hybrid operator 210, the initial estimation value of the motor coil resistance drop calculated by the multiplier 215 is sent to the hybrid operator 210, and the driving voltage V (t) at the first time is sent by the hybrid operator 210 ₁ ) Taking the first inverse number as a positive input, taking the initial estimated value of the resistance-voltage drop of the motor coil as a negative input, performing a mixed operation of addition and subtraction to obtain an estimated value of the excitation voltage of the motor coil generated at the first moment, and sending the estimated value to the first amplifier 211; the first amplifier 211 calculates the product of the excitation voltage estimation value at the first time and the first gain 1/L to obtain the excitation current change rate estimation value at the first time

And sent to the integrator 212; the rate of change estimate of the field current at the first time is used by the integrator 212

The rate of change estimate of the field current at the first time is used by the integrator 212

The integral operation formula for the integral operation is as follows:

wherein, t _n Is the current time of day and is,

is an estimated value of the change rate of the exciting current at the time tau, d is a differential sign, tau is an integral variable,

is an initial estimation value of the excitation current, which is 0. The integrator 212 may be coupled due to the low pass characteristic of the integrator 212

And smoothing and filtering ripples on the signal, which are generated by shaking of an adaptive sliding mode observer or an adaptive Luenberger observer.

The driving current I (t) at the first instant is utilized by the adaptive observer 21 ₁ ) And an estimated value of the excitation current

Calculating a motor coil resistance estimate at a first time

For predicting the coil impedance R at the first moment _T (ii) a Calculating a motor coil resistance estimate at a first time

And an estimated value of the exciting current

The second product of the first and second time points to obtain the estimated value of the resistance drop of the motor coil at the first time point.

In the examples of the present inventionCalculating the estimated value of the resistance of the motor coil at the first time

The method comprises the following specific steps: the two-input subtractor 213 calculates the drive current I (t) at the first time ₁ ) And an estimated value of the exciting current

To obtain an excitation current estimation error at the first moment

And estimating the excitation current error at the first moment

Sending to the parameter identification module 214; the estimated value of the excitation current at the first time is utilized by the parameter identification module 214

And excitation current estimation error

The estimated motor coil resistance value at the first time is then calculated by multiplier 215

And an estimated value of the exciting current

Further, the estimated value of the resistance of the motor coil at each first time

The iterative calculation formula of (a) is as follows:

wherein, L is the coil inductance of the linear resonance motor; alpha is an iteration coefficient which is a preset positive real number;

is a predetermined initial value, typically set to the nominal value of the coil resistance supplied by the manufacturer of the linear resonant motor.

In addition, the calculating a second inverse number of the estimated value of the back electromotive force at the first time includes: the two-input subtractor 213 calculates the drive current I (t) at the first time ₁ ) And an estimated value of the exciting current

To obtain an excitation current estimation error at the first moment

And estimating the excitation current error at the first moment

To the observation unit 216; the observation unit 216 utilizes the adaptive sliding mode observer gain K or the adaptive Luenberger observer gain L _d Estimating an error of the field current at the first time

Carrying out treatment; the excitation current estimation error at the first moment after the calculation processing by the second amplifier 217

And the product of the first gain L and the second gain L, a second inverse number of the back electromotive force estimated value at the first moment is obtained.

Also, in the embodiment of the present application, the adaptive observer 21 is classified into an adaptive sliding mode adaptive observer and an adaptive lunberg adaptive observer. When the adaptive observer 21 is an adaptive sliding mode adaptive observer, the observation unit 216 estimates an error of the excitation current

After sgn () operation, K is multiplied and used as output, i.e. the specific operation formula of the observation unit 216 is:

wherein sgn is a sign function, and K is the gain of the adaptive sliding mode adaptive observer. The larger K is, the faster the tracking speed of the sliding mode adaptive observer is, and the more stable the system is, but the more serious the shake phenomenon is at the moment. When the adaptive observer 21 is an adaptive lunberg adaptive observer, the observation unit 216 directly estimates the error using the excitation current

Combining a second inverse number calculated by the adaptive observer 21 based on the previous time and the estimated value of the resistance-voltage drop of the motor coil with the driving voltage V (t) at the current time _n ) To obtain the estimated value of the exciting current at each subsequent time

In this case, n > 1.

In the embodiment of the invention, the estimation value of the excitation current at each subsequent moment is obtained

The method comprises the following specific steps: the voltage detection ADC 11 detects the drive voltage V (t) of the linear resonant motor 3 at each subsequent time in real time _n ) Sending the current driving voltage V (t) to the hybrid operator 210, sending a second inverse number calculated by the second amplifier 217 at a previous time to the hybrid operator 210, sending a motor coil resistance-voltage drop estimated value calculated by the multiplier 215 at a previous time to the hybrid operator 210, and sending the driving voltage V (t) at the current time to the hybrid operator 210 _n ) Taking the second inverse number of the previous moment as a positive input, taking the resistance-voltage drop estimation value of the motor coil of the previous moment as a negative input, performing addition and subtraction mixed operation to obtain the excitation voltage estimation value of the motor coil generated at each subsequent moment, and sending the excitation voltage estimation value of the motor coil generated at each subsequent moment to the first amplifier 211; the first amplifier 211 calculates the product of the excitation voltage estimation value and the first gain 1/L at each subsequent time to obtain the excitation current change rate estimation value at each subsequent time

And sent to the integrator 212; integrator 212 uses the field current rate of change estimates at subsequent times

Further, the estimated value of the change rate of the exciting current at each subsequent moment is utilized

The integral operation formula for the integral operation is as follows:

wherein, t _n Is the current time of day and is,

the initial estimation value of the exciting current is 0, and n is more than 1.

The driving current I (t) at each subsequent time is utilized by the adaptive observer 21 _n ) And an estimated value of the excitation current

For the predicted coil impedance R at subsequent respective times _T (ii) a Calculating the resistance estimated value of the motor coil at each subsequent time

And an estimated value of the exciting current

The second product of the first and second time points is obtained to obtain the estimated value of the resistance voltage drop of the motor coil at each subsequent time point.

In the embodiment of the invention, the estimated value of the resistance of the motor coil at each subsequent moment is calculated

The second inverse number of the estimated resistance drop value and the estimated back electromotive force value of the motor coil comprises the following specific steps: the two-input subtractor 213 calculates the driving current I (t) at each subsequent time _n ) And exciting currentFlow estimation

To obtain the estimation error of the exciting current at each subsequent time

And sent to the parameter identification module 214; the estimated value of the excitation current at each subsequent time is used by the parameter identification module 214

And excitation current estimation error

The multiplier 215 calculates the estimated motor coil resistance at each subsequent time

And an estimated value of the exciting current

Obtaining the estimated value of the resistance voltage drop of the motor coil at each subsequent moment by the second product; the observation unit 216 estimates the error of the excitation current at each subsequent time by using the gain K of the adaptive sliding mode observer or the gain Ld of the adaptive lunberger observer

Carrying out treatment; the excitation current estimation error at each subsequent time after processing is calculated by the second amplifier 217

Multiplying the second gain L to obtain a second inverse of the estimated value of the back electromotive force at each subsequent timeAnd (4) counting.

Further, the estimated values of the resistance of the motor coil at the subsequent time points

The iterative calculation formula of (a) is as follows:

The second inverse number of the estimated value of the back electromotive force at each subsequent time calculated by the second amplifier 217 is sent to the third amplifier 218, and the first product of the second inverse number at each subsequent time and-1 is calculated by the third amplifier 218 and sent to the low-pass filter 219; the low-pass filter 219 filters the ripple wave generated by the adaptive observer due to the dithering based on the first product, and obtains and outputs the estimated value of the back electromotive force at each time.

The error signal is obtained by the drive voltage controller 22 calculating the difference between the input amplitude and the predicted back emf.

The phase difference between the predicted back electromotive force and the current driving voltage waveform is compared by the F0 detection module 23, and a phase difference comparison result is obtained.

The amplitude and frequency variable periodic signal is generated by the driving waveform DDS 24, the amplitude of the periodic signal is adjusted by using an error signal, and the frequency of the periodic signal is adjusted by using a phase difference comparison result.

Further, adjusting the amplitude of the periodic signal by using the error signal specifically includes: comparing the magnitude of the error signal with a 0 value; if the error signal is less than 0, increasing the amplitude of the periodic signal; if the error signal is greater than 0, the amplitude of the periodic signal is reduced.

In addition, adjusting the frequency of the periodic signal by using the phase difference comparison result specifically includes: if the predicted phase of the back electromotive force lags behind the phase of the current driving voltage waveform, reducing the frequency of the periodic signal; and if the phase of the predicted back electromotive force is ahead of the phase of the current driving voltage waveform, increasing the frequency of the periodic signal.

The PWM signal is generated by the PWM modulator 25 using the periodic signal.

The linear resonant motor 3 is driven by the driving circuit 13 by converting the PWM signal into a voltage signal.

Preferably, a linear resonant motor driving method disclosed in an embodiment of the present invention further includes: judging whether the amplitude of the periodic signal reaches the maximum driving voltage allowed by the linear resonant motor or not through a driving waveform DDS 24; when the amplitude of the periodic signal reaches the maximum driving voltage allowed by the linear resonant motor, the driving waveform DDS 24 inputs the periodic signal to the PWM modulator 25, and drives the linear resonant motor with the maximum driving voltage signal via the driving circuit 13.

Further, corresponding to the linear resonant motor driving system disclosed in the first embodiment of the present invention, the linear resonant motor driving method disclosed in the embodiment of the present invention further includes: judging whether the predicted back electromotive force is larger than a preset rated back electromotive force threshold value or not through the amplitude protection module 26; if the predicted back electromotive force is larger than a preset rated back electromotive force threshold value, triggering amplitude protection and stopping the driving circuit 3; if the predicted back electromotive force is not greater than the preset rated back electromotive force threshold, the amplitude protection is not triggered, and the driving circuit 3 is not stopped.

During operation of the linear resonant motor, the coils thereof generate heat due to the application of an excitation current. If the coil generates heat for a long time and cannot be timely diffused, high temperature can be generated inside the LRA, so that the amplitude control precision of the oscillator is poor, noise occurs, and even permanent damage occurs.

Corresponding to the linear resonant motor driving system disclosed in the first embodiment of the present invention, the linear resonant motor driving method disclosed in the embodiment of the present invention further includes: coil resistance R obtained by the temperature calculation module 27 based on the prediction _T Calculating the temperature T of the motor coil by using a temperature calculation formula, wherein the temperature calculation formula comprises the following steps:

wherein R is ₂₅ Is the coil impedance at 25 ℃, T _coef Is the temperature coefficient of the motor coil.

Judging whether the temperature T of the motor coil exceeds a preset temperature protection threshold value or not through a temperature protection module 28; if the temperature T of the motor coil exceeds a preset temperature protection threshold value, triggering temperature protection and stopping the driving circuit 3; judging whether the temperature T of the motor coil is less than a preset temperature protection release threshold value or not; and if the temperature T of the motor coil is less than the preset temperature protection release threshold value, the driving circuit 3 is recovered.

Further, in correspondence with the linear resonant motor driving system disclosed in the second embodiment of the present invention, the linear resonant motor driving method disclosed in the embodiment of the present invention further includes: generating a first amplitude input attenuation factor by the amplitude control module 29; calculating a first product of a first amplitude input attenuation coefficient and the input amplitude to obtain an adjusted input amplitude; the difference between the adjusted input amplitude and the predicted back emf is calculated by the drive voltage controller 22 to obtain an error signal.

Further, the first amplitude input attenuation coefficient is greater than 0 and less than or equal to 1; judging whether the predicted back electromotive force peak value is higher than a first back electromotive force preset threshold value Vth1 by the amplitude control module 29; if the predicted peak value of the back electromotive force is higher than the first preset threshold Vth1, determining whether the first duration of the predicted peak value of the back electromotive force higher than the first preset threshold Vth1 reaches the first preset time t ₁ (ii) a If the first duration reaches the first predetermined time t ₁ Decreasing the first amplitude input attenuation factor; judging whether the predicted back electromotive force peak value is smaller than a second back electromotive force preset threshold value Vth 2; if the predicted peak value of the back electromotive force is smaller than the second back electromotive force preset threshold Vth2, determining whether a second duration time, during which the predicted peak value of the back electromotive force is smaller than the second back electromotive force preset threshold Vth2, reaches a second preset time t ₂ (ii) a If the second duration reaches the second preset time t ₂ And reducing the first amplitude input attenuation coefficient.

Corresponding to the linear resonant motor driving system disclosed in the second embodiment of the present invention, the linear resonant motor driving method disclosed in the embodiment of the present invention further includes: coil impedance R obtained by temperature calculation module 27 based on prediction _T Calculating the temperature T of the motor coil by using a temperature calculation formula, wherein the temperature calculation formula comprises the following steps:

Judging whether the temperature T of the motor coil exceeds a preset temperature protection threshold value through a temperature protection module 28; if the temperature T of the motor coil exceeds a preset temperature protection threshold value, triggering temperature protection and stopping the driving circuit 3; judging whether the temperature T of the motor coil is less than a preset temperature protection release threshold value or not; if the motor coil temperature T is less than the preset temperature protection release threshold, the driving circuit 3 is recovered.

Further, corresponding to the linear resonant motor driving system disclosed in the third embodiment of the present invention, the linear resonant motor driving method disclosed in the embodiment of the present invention further includes: judging whether the predicted back electromotive force is larger than a preset rated back electromotive force threshold value or not through the amplitude protection module 26; if the predicted back electromotive force is larger than a preset rated back electromotive force threshold value, triggering amplitude protection and stopping the driving circuit 3; if the predicted back electromotive force is not greater than the preset rated back electromotive force threshold, the amplitude protection is not triggered, and the driving circuit 3 is not stopped.

Corresponding to the linear resonant motor driving system disclosed in the third embodiment of the present invention, the linear resonant motor driving method disclosed in the embodiment of the present invention further includes: coil resistance R obtained by the temperature calculation module 27 based on the prediction _T Calculating the temperature T of the motor coil by using a temperature calculation formula, wherein the temperature calculation formula comprises the following steps:

Generating a second amplitude input attenuation factor by the temperature control module 210; calculating a second product of the second amplitude input attenuation coefficient and the input amplitude to obtain an adjusted input amplitude; the difference between the adjusted input amplitude and the predicted back emf is calculated via the drive voltage controller 22 to obtain an error signal.

Wherein the second amplitude input attenuation coefficient is greater than 0 and less than or equal to 1. Judging whether the temperature T of the motor coil is higher than a first preset temperature threshold through a temperature control module 210Value T ₁ (ii) a If the temperature T of the motor coil is higher than a first temperature preset threshold T ₁ If so, judging that the temperature T of the motor coil is higher than a first preset temperature threshold T ₁ Whether the third duration of time of (2) reaches the third preset time t ₃ (ii) a If the third duration reaches the third preset time t ₃ Decreasing the second amplitude input attenuation factor; judging whether the temperature T of the motor coil is less than a second preset temperature threshold T or not ₂ (ii) a If the motor coil temperature T is less than a second temperature preset threshold T ₂ If so, judging that the temperature T of the motor coil is less than a second preset temperature threshold T ₂ Whether the fourth duration reaches the fourth preset time t ₄ (ii) a If the fourth duration reaches the fourth predetermined time t ₄ And increasing the first amplitude input attenuation coefficient.

The above three embodiments of the present invention only exemplify the combination of each functional module, element, and device, and do not limit the scope of the present invention in any combination of each functional module, element, and device described in the above embodiments.

Compared with the prior art, the linear resonant motor driving method provided by the embodiment of the application is based on IV detection and driving of a linear resonant motor, can detect the driving voltage V and the driving current I of the linear resonant motor in real time under the condition of not stopping the driving circuit, and estimates the back electromotive force and the coil impedance of the linear resonant motor in real time by using an adaptive Sliding mode adaptive Observer (slipping mode Observer) or an adaptive luneberg adaptive Observer (Luenberger Observer), so as to realize the resistance value R of a motor coil _T And real-time estimation of the induced electromotive force BEMF, improve the accuracy of F0 tracking and LRA amplitude control. Even if R changes due to factors such as interface plugging and unplugging, environment temperature change, motor long vibration temperature rise and the like, the BEMF detection value can be detected in real time to ensure correct detection of the BEMF detection value. Meanwhile, the linear resonant motor driving method disclosed in the embodiment of the invention can also realize the functions of amplitude protection, amplitude control, temperature protection and temperature controlCan be used.

In the embodiment of the invention, the driving waveform cannot be stopped due to the detection of the driving voltage V and the driving current I, so that the defects of the prior art, such as poor amplitude consistency, conduction of a parasitic diode of a power tube, audio noise and the like, can be avoided.

In the embodiment of the invention, the back electromotive force information can be detected in real time, and the BEMF information is not detected only at the zero crossing point. Therefore, the control of the linear resonant motor with higher precision and speed can be realized, which mainly comprises the following steps:

eliminating higher harmonics of the drive voltage waveform caused by zero crossing windowing detection;

the vibrator speed of the linear resonant motor is controlled in real time, and the amplitude inconsistency of the driving voltage waveform caused by zero-crossing windowing detection is eliminated;

the amplitude attenuation of the driving voltage caused by zero-crossing windowing detection is eliminated, and the maximum output amplitude is increased by 10-20% under the same power supply voltage;

the parameter identification module is used for estimating and detecting the resistance of the motor coil in real time, so that the problem of detection error of the BEMF caused by the drift of the resistance of the motor coil in the traditional IV detection is solved;

the BEMF voltage is tracked by adopting a self-adaptive sliding mode self-adaptive observer or a self-adaptive Luenberg self-adaptive observer, so that the calculated amount is reduced, the tracking speed is increased, and the system stability is improved;

the real-time estimation value of the resistance of the motor coil and the temperature coefficient of the resistance of the motor coil are estimated by using the parameter identification module, and the estimation value of the real-time temperature of the resistance of the motor coil can be calculated. When the motor coil is overheated, corresponding vibration stopping protection or attenuation of the amplitude of the driving voltage waveform can be carried out, so that the failure of the motor coil caused by overheating is avoided. When the temperature of the motor coil is lower, the amplitude of the driving voltage waveform is increased to compensate the amplitude attenuation of the vibrator caused by the increase of the magnetofluid viscosity coefficient at low temperature.

Although the invention has been described in detail with respect to the general description and the specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A linear resonant motor drive method, comprising:

predicting the back electromotive force and the coil impedance R in the motor working process by using the driving voltage V and the driving current I _T ；

comparing the phase difference of the predicted back electromotive force and the current driving voltage waveform to obtain a phase difference comparison result;

generating a PWM signal using the periodic signal;

2. The linear resonance motor driving method as claimed in claim 1, wherein the back electromotive force and the coil impedance R during the operation of the motor are predicted using the driving voltage V and the driving current I _T The method comprises the following steps:

initial estimation value based on set exciting current

Obtaining a first inverse number of the initial resistance voltage drop estimation value and the initial back electromotive force estimation value of the motor coil;

using the drive voltage V (t) at the first moment ₁ ) The first inverse number and the initial estimated value of the resistance voltage drop of the motor coilCalculating an estimated value of the exciting current at the first time

Calculating a motor coil resistance estimate at a first time

For predicting the coil impedance R at the first moment _T ；

Calculating a motor coil resistance estimate at a first time

And an estimated value of the exciting current

Calculate subsequent onesMotor coil resistance estimate at time

And a second inverse of the estimate of back EMF, the estimate of motor coil resistance at each subsequent time instant

For the predicted coil impedance R at subsequent respective times _T ；

And an estimated value of the exciting current

calculating a first product of the second inverse number and-1 at each moment; and

3. The linear resonant motor driving method of claim 1, wherein adjusting the amplitude of the periodic signal with the error signal comprises:

comparing the magnitude of the error signal with a 0 value;

4. A linear resonant motor drive method as set forth in claim 3, further comprising:

5. The linear resonant motor driving method of claim 1, wherein adjusting the frequency of the periodic signal using the phase difference comparison result comprises:

6. The linear resonant motor driving method as set forth in any one of claims 1 to 5, further comprising:

7. The linear resonant motor driving method as recited in claim 6, further comprising:

generating a first amplitude input attenuation coefficient;

calculating the difference between the adjusted input amplitude and the predicted back electromotive force to obtain an error signal;

if the predicted peak value of the back electromotive force is higher than the first preset threshold Vth1, determining whether the first duration of the predicted peak value of the back electromotive force higher than the first preset threshold Vth1 reaches the first preset time t ₁ ；

if the predicted peak value of the back electromotive force is smaller than the second back electromotive force preset threshold Vth2, determining whether a second duration time, during which the predicted peak value of the back electromotive force is smaller than the second back electromotive force preset threshold Vth2, reaches a second preset time t ₂ ；

8. The linear resonant motor driving method as set forth in any one of claims 1 to 5, further comprising:

9. A linear resonant motor drive method as set forth in claim 8, further including:

generating a second amplitude input attenuation coefficient;

judging whether the temperature T of the motor coil is higher than a first preset temperature threshold T or not ₁ ；

If the third duration reaches the third predetermined time t ₃ Decreasing the second amplitude input attenuation factor;

If the fourth duration reaches the fourth preset time t ₄ Increasing the first vibrationThe amplitude is input to the attenuation coefficient.

10. A linear resonant motor drive system, the system comprising:

The driving voltage controller is used for calculating the difference value between the input amplitude and the predicted back electromotive force to obtain an error signal;