Waveform Generator for Ultrasonic Transducers
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Solution Overview
Problem
Conventional electronic signal generators for ultrasonic applications are limited in their ability to accommodate a wide range of transducer and load combinations, requiring costly and time-consuming redesigns for each specific application, and often result in unstable operation due to high dynamic impedance ranges and phase shift variations.
Innovation Solution
A digital signal processor-based electrical waveform generator that digitally synthesizes waveforms, adjusts voltage and current, and uses sensing and conditioning circuitry to maintain optimal phase and amplitude alignment, allowing for broader compatibility with various transducer and load configurations while minimizing hardware changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional electronic signal generators use traditional PLL techniques and AGC circuitry, then they can provide frequency and voltage control, but they require costly and time-consuming redesigns for each specific application and have limited ability to accommodate wide range of transducer and load combinations
Solution Approach 1:
The patent implements a microprocessor-based control system that dynamically adjusts operating parameters (frequency, voltage, phase) to adapt to different transducer and load combinations. The system measures impedance and phase characteristics, then modifies control parameters in real-time to optimize performance for each specific application without requiring hardware redesign.
Solution Approach 2:
The generator is designed as a universal platform that can drive various types of electromechanical transducers (piezoelectric, magnetostrictive) and accommodate different load conditions through software-based control. The microprocessor executes adaptive algorithms that enable the same hardware to serve multiple applications by changing operational parameters rather than physical configuration.
2Reliability
If conventional generators are designed for specific applications with optimized hardware, then they provide stable operation, but they cannot be easily adapted to other applications without redesign
Solution Approach 1:
The system incorporates impedance sensing and phase detection circuits that provide real-time feedback to the microprocessor. Based on this feedback, the controller dynamically adjusts frequency and voltage to maintain stable operation at resonance. This closed-loop feedback mechanism ensures reliable performance across different applications while eliminating the need for application-specific hardware optimization.
Solution Approach 2:
The generator transitions from static, application-specific hardware design to dynamic, software-based parameter adjustment. The microprocessor continuously monitors system characteristics and modifies operating parameters in real-time, enabling the same hardware to adapt to varying application requirements while maintaining operational stability through active control.
3Measurement precision
If the frequency difference between Series and Parallel Resonance is very small (a few hertz), then standard PLL systems require low loop gain to capture and lock, but this makes the system unstable in normal operating modes
Solution Approach 1:
The system dynamically adjusts PLL loop gain based on operating conditions and detected resonance characteristics. During frequency acquisition, the loop gain is set to enable capture of small frequency differences. Once locked, the gain is reduced to maintain stability. This dynamic gain adjustment allows the system to handle both frequency capture and stable operation requirements.
Solution Approach 2:
The system performs preliminary impedance and phase measurements to identify resonance characteristics before attempting frequency lock. Based on these preliminary measurements, the controller pre-configures optimal loop parameters including gain settings tailored to the specific transducer characteristics, enabling successful capture and stable operation.
4Measurement precision
If the phase characteristic curve is flattened, then the PLL may not recognize the phase shift at series or parallel resonance, but hardware redesign is required to optimize the curve
Solution Approach 1:
The system uses real-time phase measurement feedback to detect resonance conditions even when the phase characteristic curve is flattened. The microprocessor continuously monitors phase relationships between voltage and current, identifying resonance points through algorithmic analysis rather than relying on pronounced phase shifts. This eliminates the need for hardware redesign to optimize phase curves for specific applications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and stable operation across a wider range of ultrasonic applications with reduced costs and complexity, by dynamically adjusting frequency and amplitude to maintain resonance and minimize distortion, thus enhancing the usability of ultrasound technology.
Implementation Method 1
a waveform generator component connected to an output of the computing unit for digitally synthesizing an electrical waveform of a desired frequency
Implementation Method 2
an amplifier section connected at a control input to an output of the waveform generator component and adjusts at least one of a voltage and a current of the waveform
Implementation Method 3
The sensing and conditioning circuit componentry is operatively connected to the amplifier section for sensing and conditioning an output current and an output voltage of the amplifier section across the electromechanical load
Implementation Method 4
piezoelectric and magnetostrictive transducers
Implementation Method 5
piezoelectric and magnetostrictive transducers
Implementation Method 6
The minimum impedance point IPMIN of the curve is generally regarded as the series resonance and the maximum impedance point IPMAX is considered the anti-resonance or parallel resonance of the transducer
Data Source
AI summary
An electrical waveform generator for driving an electromechanical load includes a digital signal processor connected to a waveform generator component in turn connected to an amplifier section with a filter network, the latter being connected to sensing and conditioning circuit componentry that is in turn connected to analog-to-digital converter circuitry. A digital memory stores digitized voltage and current waveform information. The processor determines a phase difference between voltage and current waveforms, compares the determined phase difference to a phase difference command and generates a phase error or correction signal. The processor also generates an amplitude error signal for inducing the amplifier section to change its output amplitude to result in a predetermined amplitude error level for a respective one of the voltage and current waveforms.