Piezoelectric Element Driving Circuit Current Regulation
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Solution Overview
Problem
Piezoelectric element driving circuits face issues where increasing driving current decreases pressure and flow rate efficiency, leading to power loss and potential element cracking, and existing solutions that regulate current using sensors increase costs.
Innovation Solution
A piezoelectric element driving circuit with a power supply circuit, driving circuit, and control circuit that generates and regulates a driving signal to maintain a constant current, using a boosting circuit and control signals to adjust DC supply voltage, eliminating the need for pressure or flow rate sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If driving current is increased to improve pressure generation, then pressure increases, but power loss increases and battery life shortens
Solution Approach 1:
The patent implements a feedback mechanism where the control circuit continuously monitors the driving current flowing through the piezoelectric element and adjusts the driving signal accordingly. This feedback loop enables the system to maintain optimal current levels that generate sufficient pressure while minimizing power consumption and preventing excessive energy loss.
Solution Approach 2:
The driving signal is dynamically adjusted based on real-time current measurements. The control circuit modifies the amplitude and frequency of the driving signal adaptively, allowing the piezoelectric element to operate at optimal conditions that balance pressure generation with energy efficiency, rather than using fixed high current levels.
2Stress or pressure
If driving current is increased to improve pressure generation, then pressure increases, but flow rate efficiency decreases
Solution Approach 1:
The control circuit dynamically adjusts the driving signal parameters (amplitude, frequency, pulse width) based on monitored current levels and system response. This dynamic control optimizes the balance between pressure generation and fluid flow efficiency, ensuring that the piezoelectric pump operates at the optimal point on its performance curve rather than at extreme current levels.
Solution Approach 2:
The patent changes multiple driving parameters simultaneously (current amplitude, frequency, pulse duration) to achieve optimal performance. By adjusting these parameters in combination rather than relying solely on current magnitude, the system maintains both adequate pressure and efficient flow rate.
3Stress or pressure
If excessive driving current flows through the piezoelectric element, then pressure generation improves, but the piezoelectric element may crack
Solution Approach 1:
The control circuit continuously monitors the actual current flowing through the piezoelectric element and compares it against safe operating thresholds. When approaching dangerous current levels, the feedback mechanism automatically reduces the driving signal amplitude, preventing excessive stress that could cause element cracking while still maintaining adequate pressure generation within safe limits.
Solution Approach 2:
The system implements protective control that anticipates dangerous conditions by monitoring current trends and adjusting the driving signal before excessive current can cause damage. This preemptive control prevents the piezoelectric element from being subjected to stress levels that would lead to cracking or failure.
4Reliability
If pressure sensor or flow rate sensor is used to regulate driving current, then current control improves, but manufacturing cost increases
Solution Approach 1:
The system uses the existing electrical characteristics of the piezoelectric element and the driving circuit itself to generate the control signal. By extracting current information from the driving circuit's own operation and using the piezoelectric element's inherent resonant properties, the system achieves accurate current regulation without requiring external pressure or flow rate sensors, significantly reducing manufacturing costs.
Solution Approach 2:
The control circuit performs multiple functions simultaneously: it generates the driving signal, monitors the current, processes the signal, and adjusts the output. This multi-functional approach eliminates the need for separate sensor components and their associated circuitry, reducing both component count and manufacturing complexity while maintaining reliable current control.
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
This configuration maintains optimal driving conditions for the piezoelectric element, maximizing pressure and flow rate efficiency while reducing power loss and preventing element cracking without the need for additional sensors, thus extending battery life.
Implementation Method 1
a piezoelectric element driving circuit that applies a driving signal to a piezoelectric element
Implementation Method 2
the piezoelectric element driving circuit can drive the piezoelectric element at a resonant frequency
Data Source
AI summary
A piezoelectric element driving circuit includes a boosting circuit, a driving circuit, a waveform shaping circuit, and a computing circuit. The driving circuit includes a differential amplifier circuit with an LPF, an amplifier circuit with a BPF, an inverter, a resistor, and a comparator. The driving circuit applies a driving signal to a piezoelectric element of a piezoelectric pump. The waveform shaping circuit extracts a voltage signal from the driving circuit. On the basis of the voltage signal, the waveform shaping circuit and the computing circuit determine a voltage value corresponding to driving current flowing through the piezoelectric element. The computing circuit outputs a control signal to the boosting circuit on the basis of the voltage value. The boosting circuit sets the value of a DC supply voltage on the basis of the control signal, and outputs the DC supply voltage.