A driving circuit system and an adaptive frequency modulation method of an ultrasonic transducer

Abstract

This invention discloses a driving circuit system and adaptive frequency modulation method for an ultrasonic transducer. The driving circuit system, used to adjust the driving frequency of the ultrasonic transducer, includes a microcontroller processing unit, a driving signal enhancement circuit, a push-pull output driving circuit, a high-frequency transformer, an ultrasonic transducer impedance matching circuit, a push-pull output driving current sampling circuit, a high-frequency transformer output voltage sampling circuit, and a power supply circuit. The adaptive frequency modulation method involves the microcontroller processing unit searching for the resonant operating frequency of the ultrasonic transducer under the current operating environment through the driving circuit in the initial state; and adaptively adjusting the ultrasonic transducer to the resonant frequency during operation. This invention achieves adaptive dynamic frequency adjustment of the ultrasonic transducer without manual tuning; furthermore, since the frequency range is F0±FC, the frequency adjustment range is wide; and the hardware technology is simple, with few components and low cost.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic transducer operating frequency control technology, specifically to a driving circuit system for an ultrasonic transducer and an adaptive frequency modulation method. Background Technology

[0002] Traditional ultrasonic transducer drive circuits use inductors, piezoelectric ceramics, and other components to form an LC resonant circuit. When the ultrasonic transducer and the resonant circuit impedance are matched, it operates at the resonant frequency. However, when the ultrasonic environment changes, the optimal resonant frequency of the ultrasonic transducer cannot be met, and manual tuning is required to achieve the best operating state.

[0003] Existing ultrasonic transducer driving technologies also include methods that use hardware phase-locked loop (PLL) drive control circuits to track the ultrasonic transducer's operating frequency. Because ultrasonic transducers operate at relatively high frequencies, this approach places high demands on hardware configuration, component precision, and feedback signal quality, increasing the complexity and cost of the entire drive circuit. Furthermore, the PLL drive control circuit has a relatively narrow frequency tracking range and requires a large number of components, making it unsuitable for this product application. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a driving circuit system for an ultrasonic transducer and an adaptive frequency modulation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a driving circuit system for an ultrasonic transducer, the driving circuit system being used to adjust the driving frequency of the ultrasonic transducer so that the ultrasonic transducer operates at a resonant frequency, comprising a microcontroller processing unit, a driving signal enhancement circuit, a push-pull output driving circuit, a high-frequency transformer, an ultrasonic transducer impedance matching circuit, a push-pull output driving current sampling circuit, a high-frequency transformer output voltage sampling circuit, and a power supply circuit.

[0006] The microcontroller processing unit is used to sample the operating voltage of the ultrasonic transducer in real time, sample the operating current of the push-pull output drive circuit in real time, preset the driving frequency range of the ultrasonic transducer, implement the adaptive frequency modulation algorithm of the ultrasonic transducer operating frequency by the embedded drive circuit system, and output the PWM drive signal.

[0007] The drive signal enhancement circuit is used to receive the PWM push-pull drive signal output by the microcontroller processing unit and amplify the PWM push-pull drive signal. Its output terminal is connected to the push-pull output drive circuit.

[0008] The push-pull output drive circuit is used to receive the PWM push-pull drive signal amplified by the drive signal enhancement circuit, and control the power amplification. Its output terminal is connected to the high-frequency transformer.

[0009] The high-frequency transformer is used to transmit the PWM signal from the push-pull output drive circuit to the ultrasonic transducer to generate a high-frequency high-voltage signal to drive the ultrasonic transducer.

[0010] The ultrasonic transducer impedance matching circuit, together with the internal resistance and capacitance of the ultrasonic transducer itself, forms a matching circuit to constitute a resonant circuit.

[0011] The push-pull output drive current sampling circuit is used to obtain the magnitude of the drive current in real time and output it to the microcontroller processing unit.

[0012] The high-frequency transformer output voltage sampling circuit is used to acquire the driving voltage of the ultrasonic transducer in real time and output it to the microcontroller processing unit.

[0013] Power supply circuit, used to provide operating power.

[0014] The present invention also provides an adaptive frequency modulation method for an ultrasonic transducer, the adaptive frequency modulation method comprising:

[0015] In the initial state, the drive circuit system searches within a preset frequency range for the resonant frequency of the ultrasonic transducer in the working environment;

[0016] In operation, when the actual operating frequency of the ultrasonic transducer does not match the resonant frequency, the drive circuit system automatically adjusts the frequency of the output PWM signal to make the ultrasonic transducer reach the resonant frequency again.

[0017] Preferably, the process by which the drive circuit system searches for the resonant frequency of the ultrasonic transducer within a preset frequency range under the operating environment is as follows:

[0018] When the ultrasonic transducer is placed in the working environment, the microcontroller processing unit outputs two sets of PWM push-pull drive signals sequentially within the preset frequency range, and simultaneously obtains the data corresponding to the two sets of PWM push-pull signals at each frequency point. The data includes: the voltage value obtained by the microcontroller processing unit through the high-frequency transformer output voltage sampling circuit, and the current value obtained by the microcontroller processing unit through the push-pull output drive current sampling circuit.

[0019] The microcontroller processing unit calculates the idle percentage of the high-frequency switching voltage output of the high-frequency transformer for each frequency point based on the voltage value obtained by the high-frequency transformer output voltage sampling circuit.

[0020] The microcontroller processing unit first selects a frequency point with an idle ratio between 45% and 50%. Then, it selects the frequency point corresponding to the minimum current value obtained by the microcontroller processing unit through the push-pull output drive current sampling circuit for the frequency point with an idle ratio between 45% and 50%. This frequency point is the resonant frequency of the current ultrasonic transducer, which is used as the operating frequency of the subsequent ultrasonic transducer in this working environment.

[0021] Preferably, in operation, when the actual operating frequency of the ultrasonic transducer does not match its resonant frequency, the drive circuit system automatically adjusts the frequency of the output PWM signal to bring the ultrasonic transducer back to its resonant frequency. The process is as follows:

[0022] When the ultrasonic transducer is working, the microcontroller processing unit monitors the voltage value obtained by the high-frequency transformer output voltage sampling circuit and the current value obtained by the push-pull output drive current sampling circuit in real time. The microcontroller processing unit adjusts the output frequency of the two sets of PWM push-pull drive signals to bring the ultrasonic transducer back to the standard operating frequency.

[0023] Preferably, the frequency range is F0±FC, where F0 is the natural frequency of the ultrasonic transducer and FC is a frequency constant.

[0024] The present invention has the following beneficial effects:

[0025] Since different working environments affect the actual operating frequency of ultrasonic transducers, this invention uses a drive circuit system to first search for the resonant operating frequency (i.e., the optimal operating frequency) of the ultrasonic transducer within a preset frequency range for that specific working environment. Then, during operation, the drive circuit system adaptively adjusts the ultrasonic transducer to the resonant operating frequency when its actual operating frequency deviates from the resonant operating frequency. This invention achieves adaptive dynamic frequency adjustment without manual tuning. Furthermore, because the frequency range is F0±FC, the frequency adjustment range is wide. Additionally, the hardware technology is simple, requires fewer components, and is low-cost. Attached Figure Description

[0026] Figure 1 The present invention provides an overall structural diagram of a driving circuit system for an ultrasonic transducer;

[0027] Figure 2 The present invention provides a circuit diagram of a driving circuit system for an ultrasonic transducer;

[0028] Figure 3 The present invention provides a flowchart of an adaptive frequency modulation method for an ultrasonic transducer. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] Reference Figure 1-3 The present invention provides an embodiment of an ultrasonic transducer driving circuit system, which is used to adjust the driving frequency of the ultrasonic transducer so that the ultrasonic transducer operates at the resonant frequency. The system includes a microcontroller processing unit, a driving signal enhancement circuit, a push-pull output driving circuit, a high-frequency transformer, an ultrasonic transducer impedance matching circuit, a push-pull output driving current sampling circuit, a high-frequency transformer output voltage sampling circuit, and a power supply circuit.

[0031] The microcontroller processing unit samples the working voltage of the ultrasonic transducer (i.e., the output voltage of the high-frequency transformer) in real time, samples the working current of the push-pull output drive circuit in real time, presets the ultrasonic transducer drive frequency range, embeds a dynamic adjustment algorithm for the ultrasonic transducer working frequency, and outputs a PWM drive signal. It uses an MS51FB9AE microcontroller.

[0032] The drive signal enhancement circuit consists of a high-speed dual MOSFET driver MC33151, which is used to receive two sets of PWM push-pull drive signals output by the microcontroller processing unit and amplify the two sets of PWM push-pull drive signals. Its output terminal is connected to the push-pull output drive circuit.

[0033] The push-pull output drive circuit consists of two N-channel MOSFET power transistors IPP029N06N, which are used to receive two sets of PWM push-pull drive signals amplified by the drive signal enhancement circuit, and control the power amplification. Its output terminal is connected to the high-frequency transformer.

[0034] A high-frequency transformer is used to transmit the PWM signal from the push-pull output drive circuit to the ultrasonic transducer to generate a high-frequency, high-voltage signal to drive the ultrasonic transducer.

[0035] An impedance matching circuit for an ultrasonic transducer is connected to the ultrasonic transducer and forms a matching circuit with the transducer's internal resistance and capacitance to create a resonant circuit.

[0036] The push-pull output drive current sampling circuit is used to obtain the magnitude of the drive current in real time and output it to the microcontroller processing unit.

[0037] The high-frequency transformer output voltage sampling circuit is used to acquire the driving voltage of the ultrasonic transducer in real time and output it to the microcontroller processing unit.

[0038] Power supply circuit, used to provide operating power.

[0039] An adaptive frequency modulation method for an ultrasonic transducer, the adaptive frequency modulation method comprising:

[0040] In the initial state, the drive circuit system searches for the resonant operating frequency of the ultrasonic transducer in the working environment (that is, the optimal operating frequency of the ultrasonic transducer in the working environment).

[0041] The process by which the drive circuit system searches for the resonant operating frequency of the matching ultrasonic transducer under the working environment is as follows:

[0042] When the ultrasonic transducer is placed in the working environment, the processing unit outputs two sets of PWM push-pull drive signals sequentially within the frequency range (F0±3KHZ) preset by the software. At the same time, it obtains the data corresponding to the two sets of PWM push-pull signals at each frequency point. The data includes: the voltage value obtained by the processing unit through the high-frequency transformer output voltage sampling circuit and the current value obtained by the processing unit through the push-pull output drive current sampling circuit.

[0043] The processing unit calculates the idle percentage of the high-frequency switching voltage output of the high-frequency transformer for each frequency point based on the voltage value obtained by the high-frequency transformer output voltage sampling circuit.

[0044] The processing unit first selects a frequency point with an empty ratio between 45% and 50%. Then, it selects the frequency point corresponding to the minimum current value obtained by the processing unit through the push-pull output drive current sampling circuit for the frequency point with an empty ratio between 45% and 50%. This frequency point is the resonant frequency of the current ultrasonic transducer, which is used as the operating frequency of the subsequent ultrasonic transducer in this working environment.

[0045] When the ultrasonic transducer is working, the processing unit monitors the voltage value obtained by the high-frequency transformer output voltage sampling circuit and the current value obtained by the push-pull output drive current sampling circuit in real time. The processing unit adjusts the output frequency of the two sets of PWM push-pull drive signals to make the ultrasonic transducer reach the resonant operating frequency state again.

[0046] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Drive circuitry for an ultrasonic transducer, characterized by: The driving circuit system is used for adjusting the driving frequency of the ultrasonic transducer to work at the resonant frequency state, and comprises a microcontroller processing unit, a driving signal enhancement circuit, a push-pull output driving circuit, a high-frequency transformer, an ultrasonic transducer impedance matching circuit, a push-pull output driving current sampling circuit, a high-frequency transformer output voltage sampling circuit and a power supply circuit. The microcontroller processing unit is used for real-time sampling of the working voltage of the ultrasonic transducer, real-time sampling of the working current of the push-pull output driving circuit, presetting of the ultrasonic transducer driving frequency range, embedding of the driving circuit system, adaptive frequency modulation algorithm of the ultrasonic transducer working frequency and output of the PWM driving signal. The driving signal enhancement circuit is used for receiving the PWM push-pull driving signal output by the microcontroller processing unit and amplifying the PWM push-pull driving signal, and the output end is connected to the push-pull output driving circuit. The push-pull output driving circuit is used for receiving the amplified PWM push-pull driving signal from the driving signal enhancement circuit, controlling the power amplification and connecting the output end to the high-frequency transformer. The high-frequency transformer is used for transmitting the PWM signal from the push-pull output driving circuit to the ultrasonic transducer end to generate a high-frequency high-voltage signal to drive the ultrasonic transducer. The ultrasonic transducer impedance matching circuit is used for matching the impedance of the ultrasonic transducer with the internal resistance and capacitance of the ultrasonic transducer to form a resonant circuit. The push-pull output driving current sampling circuit is used for real-time acquisition of the driving current in the push-pull output driving circuit and output to the microcontroller processing unit to provide driving current data for the adaptive frequency modulation of the ultrasonic transducer working frequency. The high-frequency transformer output voltage sampling circuit is used for real-time acquisition of the driving voltage output by the high-frequency transformer to drive the ultrasonic transducer and output to the microcontroller processing unit to provide driving voltage data for the adaptive frequency modulation of the ultrasonic transducer working frequency. The power supply circuit is used for providing a working power supply.

2. An adaptive frequency modulation method for an ultrasonic transducer, characterized by: The adaptive frequency modulation method comprises the following steps: In the initial state, the driving circuit system searches for the resonant frequency of the ultrasonic transducer in the working environment in the preset frequency range. In the working state, when the actual working frequency of the ultrasonic transducer does not match the resonant frequency, the driving circuit system automatically adjusts the frequency of the output PWM signal to make the ultrasonic transducer reach the resonant frequency state again. The process of searching for the working frequency of the ultrasonic transducer in the working environment in the preset frequency range by the driving circuit system is as follows: The ultrasonic transducer is placed in the working environment, the microcontroller processing unit outputs two groups of PWM push-pull driving signals in the preset frequency range in sequence, and obtains data corresponding to the two groups of PWM push-pull signals at each frequency point, which includes the voltage value obtained by the microcontroller processing unit through the high-frequency transformer output voltage sampling circuit and the current value obtained by the microcontroller processing unit through the push-pull output driving current sampling circuit. The microcontroller processing unit calculates the duty ratio of the high-frequency transformer output high-frequency switching voltage corresponding to each frequency point according to the voltage value obtained by the high-frequency transformer output voltage sampling circuit. The microcontroller processing unit firstly selects a frequency point with an empty occupation ratio between 45% and 50%, and secondly selects a frequency point corresponding to a current value obtained by the push-pull output driving current sampling circuit of the microcontroller processing unit and corresponding to the minimum current value, and the frequency point is the resonance frequency of the current ultrasonic transducer, which is used as the working frequency of the subsequent ultrasonic transducer in the working environment. The frequency range is F0±FC, wherein FO is the inherent frequency of the ultrasonic transducer, and FC is the frequency constant.

3. The method of claim 2, wherein: In the working state, when the actual working frequency of the ultrasonic transducer does not match the resonance frequency, the driving circuit system makes the ultrasonic transducer reach the resonance frequency state again in the following process: When the ultrasonic transducer is working, the microcontroller processing unit monitors the voltage value obtained by the high-frequency transformer output voltage sampling circuit and the current value obtained by the push-pull output driving current sampling circuit in real time, and adjusts the output frequency of the two groups of PWM push-pull driving signals to make the ultrasonic transducer reach the resonance frequency state again.

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