Silent Piezoelectric Pump Control for NPWT
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Solution Overview
Problem
Existing negative pressure wound therapy (NPWT) systems with piezoelectric pumps face challenges in maintaining silent operation due to thermal loading and inefficiencies, leading to decreased energy efficiency and reduced ability to provide desired functionality over time.
Innovation Solution
A control circuit is implemented to generate and modulate control signals for piezoelectric pumps, adjusting the root mean square (RMS) voltage based on temperature, resonance frequency, and pressure thresholds to prevent overheating and maintain optimal operation, including the use of sinusoidal waveforms and phase angle modulation in an alternating current circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If piezoelectric pump operates continuously at high power to maintain negative pressure, then wound therapy effectiveness is improved, but thermal loading increases causing overheating and loss of silent operation
Solution Approach 1:
The control circuit implements periodic duty cycling by alternating between active pumping phases and idle periods. The pump operates at high power during active phases to maintain negative pressure, then enters idle periods to dissipate heat and reduce thermal loading, preventing overheating while maintaining therapy effectiveness over extended periods.
Solution Approach 2:
The system dynamically adjusts pump operation based on real-time temperature monitoring and pressure requirements. The control circuit modulates the duty cycle percentage and timing between active/idle phases adaptively, allowing the pump to operate at full power when needed for therapy effectiveness while periodically reducing power to manage thermal loading and prevent overheating.
2Power
If piezoelectric pump operates at high duty cycle to maintain desired pressure levels, then wound therapy functionality is improved, but energy efficiency decreases due to thermal loading
Solution Approach 1:
The control circuit implements periodic duty cycling by alternating between active pumping phases and idle periods. The pump operates at high power during active phases to maintain negative pressure, then enters idle periods to dissipate heat and reduce thermal loading, preventing overheating while maintaining therapy effectiveness over extended periods.
Solution Approach 2:
The system changes operational parameters including duty cycle percentage, active phase duration, and idle period timing based on temperature thresholds and pressure requirements. By dynamically adjusting these parameters, the pump maintains effective pressure levels during active phases while reducing power consumption during idle phases, improving overall energy efficiency.
3Object-affected harmful factors
If piezoelectric pump operates silently at low power, then user experience is improved, but ability to maintain pressure with leaks is reduced
Solution Approach 1:
The control circuit implements periodic duty cycling by alternating between active pumping phases and idle periods. The pump operates at high power during active phases to maintain negative pressure, then enters idle periods to dissipate heat and reduce thermal loading, preventing overheating while maintaining therapy effectiveness over extended periods.
Solution Approach 2:
The system dynamically adjusts pump operation based on real-time temperature monitoring and pressure requirements. The control circuit modulates the duty cycle percentage and timing between active/idle phases adaptively, allowing the pump to operate at full power when needed for therapy effectiveness while periodically reducing power to manage thermal loading and prevent overheating.
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 enables continuous or semi-continuous operation of NPWT systems by reducing thermal loading, preventing overheating, and maintaining desired pressure levels, thus extending the operational life and efficiency of the devices.
Implementation Method 1
Some NPWT systems include a pump which operates to maintain the wound site at negative pressure by removing wound exudate from the wound site. In some existing NPWT systems, a piezoelectric pump is used to apply the negative pressure to the wound site.
Implementation Method 2
existing NPWT piezoelectric pumps are difficult to maintain in silent operation, due to thermal loading and other inefficiencies that development over the course of use
Data Source
AI summary
A negative pressure wound therapy device includes at least one piezoelectric pump and a control circuit. The control circuit is configured to generate a first control signal to control operation of the at least one piezoelectric pump, the control signal having a first root mean square (RMS) voltage, transmit the first control signal to the at least one piezoelectric pump, identify at least one of a change of state of the at least one piezoelectric pump or an expiration of a duration of time associated with operation of the at least one piezoelectric pump, responsive to identifying the at least one of the change of state or the expiration of the duration of time, generate a second control signal having a second RMS voltage less than the first RMS voltage, and transmit the second control signal to the at least one piezoelectric pump.