Piezoelectric Actuator Frequency Control for Temperature Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Piezoelectric actuators face issues with temperature-related resonance frequency changes, leading to decreased amplitude and rotating speed, and potential damage due to negative control chains, and the absence of temperature sensors complicates design and increases size and cost.
Innovation Solution
A piezoelectric actuator with a control unit that adjusts the driving signal's frequency and power based on phase difference and temperature characteristics, eliminating the need for temperature sensors by predicting temperature rises from frequency variations, and switching between resonance frequencies to manage impedance and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the power of the driving signal is increased to maintain rotating speed when resonance frequency decreases, then the rotating speed is maintained, but the vibrating body generates heat and temperature increases further causing resonance frequency to decrease further
Solution Approach 1:
The control unit continuously monitors the phase difference between the driving signal and detection signal, and automatically adjusts the frequency of the driving signal to maintain the phase difference within a predetermined range. This feedback mechanism prevents temperature-related frequency drift without requiring temperature sensors, resolving the contradiction by maintaining rotating speed while preventing temperature increase through intelligent control.
Solution Approach 2:
The system dynamically changes the frequency parameter of the driving signal based on detected phase difference variations. When phase difference indicates temperature-related frequency shift, the control unit adjusts the driving frequency to compensate, maintaining optimal operating conditions without increasing power and thus preventing further temperature rise.
2Reliability
If a temperature sensor detecting the temperature of the vibrating body is added, then temperature rise can be detected, but the circuit configuration becomes complicated and size and weight increase
Solution Approach 1:
The phase difference between driving signal and detection signal serves as an intermediary indicator of temperature changes. Instead of directly measuring temperature with a sensor, the system uses phase difference variations as a proxy, which naturally reflects temperature-induced frequency changes without requiring additional temperature sensing hardware.
Solution Approach 2:
The patent replaces the physical temperature sensor system with an electrical signal-based detection method. By monitoring phase difference in the electrical domain, the system infers temperature changes without mechanical or thermal contact sensors, simplifying the overall system architecture while maintaining detection capability.
3Stability of the object's composition
If the resonance frequency decreases due to temperature increase, then the amplitude of the vibrating body decreases, but increasing power to maintain amplitude causes further temperature increase
Solution Approach 1:
The control unit uses phase difference feedback to detect amplitude-related frequency shifts caused by temperature increase. When phase difference indicates such shifts, the system automatically adjusts driving frequency to maintain optimal resonance conditions, preserving amplitude without increasing power and thus preventing further temperature rise.
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 solution allows for stable operation of the piezoelectric actuator by maintaining a stable phase difference and reducing temperature-related issues, preventing damage and simplifying the design to achieve a smaller, lighter, and more cost-effective device.
Implementation Method 1
a rectangular vibrating body that includes a piezoelectric device
Implementation Method 2
a piezoelectric actuator which uses resonance of a vibrating body including a piezoelectric device
Data Source
AI summary
A piezoelectric actuator includes a frequency controller that controls the frequency and power of the driving signal, wherein when the phase difference falls within a predetermined range, the control unit stores the value of the frequency of the driving signal as a first frequency memory value, sets a voltage to a upper limit voltage value, and performs control of adjusting the frequency of the driving signal so that the phase difference is maintained to be within a predetermined range, and when the frequency of the driving signal is changed from the first frequency memory value by an amount exceeding a first value determined in advance, the control unit stores the value of the frequency of the driving signal as a second frequency memory value and sets the voltage to a lower limit voltage value lower than the upper limit voltage value.