Piezoelectric Pump Driving Circuit Frequency Adjustment
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Solution Overview
Problem
Existing driving circuits for piezoelectric actuators are specific to individual pumps, leading to high costs and inefficient operation due to fixed frequencies and potential damage from high-voltage usage, as they require separate designs for different actuators and cannot adjust frequencies optimally.
Innovation Solution
A driving circuit comprising a boost converter, control circuit, and voltage switch circuit that converts input voltage to a constant voltage, adjusts frequency through a comparator and frequency adjustment circuit, and forms a resonant circuit to optimize the operation of piezoelectric actuators by adjusting the operating frequency automatically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant-frequency driving circuit is employed to drive the piezoelectric actuator, then the driving circuit structure is simple, but the operating frequency cannot be adjusted to the optimized frequency required for the piezoelectric actuator
Solution Approach 1:
The patent employs a frequency-adjustable oscillating circuit that can dynamically change its operating frequency based on feedback from the piezoelectric actuator's resonance characteristics. The circuit includes variable capacitors or inductors that allow frequency tuning, transforming the static constant-frequency circuit into a dynamic adaptive system that matches the actuator's optimal operating frequency.
Solution Approach 2:
The patent implements a feedback mechanism where the driving circuit monitors the piezoelectric actuator's response and automatically adjusts the driving frequency to maintain optimal operation. This feedback loop enables the circuit to adapt to different actuators and operating conditions, resolving the contradiction between simple structure and frequency adjustability.
2Force
If a high-voltage driving circuit is employed to increase the deformation of the piezoelectric actuator, then the actuator deformation is increased, but the piezoelectric actuator is damaged easily or the life time is reduced
Solution Approach 1:
The patent employs periodic oscillating voltages at the piezoelectric actuator's resonant frequency rather than continuous high-voltage DC. This periodic action at resonance achieves maximum deformation with minimal voltage amplitude, avoiding the damage caused by sustained high-voltage application while maintaining effective pumping action.
Solution Approach 2:
The patent changes the electrical parameters from high-voltage DC to low-voltage AC at resonant frequency. By transforming the voltage characteristics and applying voltage at the optimal frequency, the system achieves high mechanical output without the damaging effects of high voltage stress on the piezoelectric material.
3Adaptability or versatility
If different driving circuits are designed for respective piezoelectrically actuated pumps according to their piezoelectric actuators, then each pump operates at optimized conditions, but the cost is high
Solution Approach 1:
The patent designs a universal driving circuit with adjustable frequency and voltage parameters that can accommodate multiple types of piezoelectric actuators. The circuit includes programmable control elements and adjustable components that allow it to be configured for different actuators, eliminating the need for separate dedicated circuits for each pump while maintaining optimized operation.
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 cost reduction by supporting various piezoelectric actuators with different frequencies, ensuring optimal operation and extending the life of piezoelectric actuators by automatically adjusting frequencies to required levels, thus reducing the need for multiple driving circuits.
Implementation Method 1
a piezoelectric actuator of the piezoelectrically actuated pump is driven by a driving circuit
Implementation Method 2
the control circuit and the voltage switch circuit form a resonant circuit to control the operation of the piezoelectric actuator load according to the variety of the minor voltage outputted from the piezoelectric actuator load
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A driving circuit (10) for a piezoelectrically actuated pump (20) includes a boost converter (11), a control circuit (12) and a voltage switch circuit (13). The boost converter (11) outputs a constant voltage (Vcc). The control circuit (12) includes a voltage-division circuit (123), a comparator (12a) and a frequency adjustment circuit (121). The constant voltage (Vcc) is divided by the voltage-division circuit (123) into a first voltage (V1) and a second voltage (V2). The comparator (12a) compares first voltage (V1) with second voltage (V2) so as to output a positive voltage (V+) or a negative voltage (V-). The voltage switch circuit (13) receives and feedbacks positive voltage (V+) or negative voltage (V-) to the piezoelectric actuator load (21). The control circuit (12) and the voltage switch circuit (13) form a resonant circuit to control the piezoelectric actuator load (21) according to the variety of minor voltage (Vc) outputted form the piezoelectric actuator load (21). The frequency adjustment circuit (121) detects and adjusts the variety of the minor voltage (Vc) automatically so as to adjust operating frequency of the piezoelectric actuator load (21).