Piezoelectric Pump Startup Circuit for Inrush Current Control
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Solution Overview
Problem
Piezoelectric pumps experience unstable startup, increased power consumption, and potential damage due to high inrush currents, leading to decreased efficiency and safety concerns, especially when used for medical applications where excessive pressure can harm living tissues.
Innovation Solution
A fluid control device with a piezoelectric pump incorporating a startup circuit that gradually increases the driving power supply voltage, maintaining or decreasing it during specific stages to prevent inrush currents, and using a drive control circuit to adjust the power supply voltage based on differential pressure or time elapsed to optimize operation and prevent valve collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the piezoelectric element is driven with high voltage to increase pump performance, then the pumping ability increases, but inrush current increases causing unstable vibration and potential damage
Solution Approach 1:
The startup circuit performs preliminary action by gradually increasing the driving voltage from a low initial voltage before reaching the target operating voltage. This prevents inrush current by preparing the piezoelectric element and diaphragm system in advance, allowing stable vibration to be established before full power is applied.
Solution Approach 2:
The driving voltage is dynamically adjusted through multiple stages rather than being applied statically at full voltage. The startup circuit changes the voltage level based on the operational stage (startup vs. normal operation), optimizing both reliability during startup and pumping ability during normal operation.
2Power
If the piezoelectric element is driven with high voltage to increase pump performance, then the pumping ability increases, but the piezoelectric body may crack and power efficiency decreases
Solution Approach 1:
The startup circuit performs preliminary action by gradually increasing the driving voltage from a low initial voltage before reaching the target operating voltage. This prevents inrush current by preparing the piezoelectric element and diaphragm system in advance, allowing stable vibration to be established before full power is applied.
Solution Approach 2:
The startup circuit provides beforehand cushioning by limiting the initial driving voltage to a lower level during the startup phase. This protective measure cushions the piezoelectric element against excessive stress and inrush current that could cause cracking, while still allowing the system to reach full performance safely.
3Power
If the thin top plate vibrates with large amplitude to increase pump ability, then the pumping ability increases, but the actuator and thin top plate may come into contact causing unstable vibration
Solution Approach 1:
The startup circuit performs preliminary action by gradually increasing the driving voltage from a low initial voltage before reaching the target operating voltage. This prevents inrush current by preparing the piezoelectric element and diaphragm system in advance, allowing stable vibration to be established before full power is applied.
Solution Approach 2:
The driving voltage is dynamically adjusted through multiple stages rather than being applied statically at full voltage. The startup circuit changes the voltage level based on the operational stage (startup vs. normal operation), optimizing both reliability during startup and pumping ability during normal 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
The solution reduces startup time, minimizes power consumption, and prevents damage to the pump components and living tissues by stabilizing the startup process and adjusting power supply accordingly, enhancing the overall efficiency and safety of the piezoelectric pump.
Implementation Method 1
a piezoelectric pump having a piezoelectric element; a driving circuit that receives a driving power supply voltage applied thereto and drives the piezoelectric element
Implementation Method 2
the center or the vicinity of the center of a region facing the actuator of the thin top plate 51 serves as a thin plate portion capable of bending vibration
Data Source
AI summary
A fluid control device includes a piezoelectric pump having a piezoelectric element, a driving circuit that receives a driving power supply voltage applied thereto and drives the piezoelectric element, and a startup circuit disposed between the driving circuit and an input terminal for a power supply voltage. The startup circuit increases the driving power supply voltage to a voltage (V1) lower than a constant voltage (Vc) in a first stage (P1) after startup, maintains or decreases the driving power supply voltage in a second stage (P2) following the first stage (P1), and increases the driving power supply voltage to the constant voltage (Vc) in a third stage (P3) following the second stage (P2).