Piezoelectric Converter Switching for Resonant Voltage Control
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Solution Overview
Problem
Existing electrical energy converters using piezoelectric elements are not optimal around the resonant frequency and do not provide efficient control of voltage values during constant voltage phases, leading to inefficiencies and potential common-mode voltage issues.
Innovation Solution
An electrical energy converter with at least two piezoelectric assemblies and a complementary switch that allows for improved control by connecting the ends of the assemblies to zero voltage, enabling additional voltage values and preventing common-mode voltage injection, while reducing the number of switches needed in certain configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional switching bridges are used without complementary switches, then the structure is simpler, but the control of voltage values during constant voltage phases is inefficient and common-mode voltage issues occur
Solution Approach 1:
The switching function is segmented between the original switching bridges and the complementary switches. Each complementary switch is connected to specific nodes (first ends or second ends of piezoelectric assemblies) to handle specific voltage control tasks, dividing the control function into manageable segments that improve overall control precision during constant voltage phases
Solution Approach 2:
Complementary switches act as intermediary elements between the switching bridges and the piezoelectric assemblies. These intermediary switches enable precise control of voltage values by providing additional control nodes, allowing the system to achieve better voltage regulation without directly modifying the main switching bridge structure
2Manufacturing precision
If more switches are added to improve voltage control, then the control precision improves, but the device complexity and switch requirements increase
Solution Approach 1:
The complementary switches serve multiple functions: they control voltage values during constant voltage phases, prevent common-mode voltage injection, and work in coordination with the existing switching bridges. This multi-functionality allows improved voltage control precision without proportionally increasing the total number of switches in the system
Solution Approach 2:
The system dynamically configures the switching states of complementary switches based on operational requirements. During constant voltage phases, complementary switches are activated to provide precise control, while during other phases they remain inactive, allowing the system to adapt its complexity to the immediate control needs
3Reliability
If complementary switches are added to prevent common-mode voltage, then the reliability improves, but the device complexity increases
Solution Approach 1:
The complementary switches convert the potential harmful effect of common-mode voltage into a controlled condition. By providing additional control nodes, the system can actively prevent common-mode voltage injection, turning a reliability concern into a controlled parameter that enhances overall system reliability
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 provides enhanced control over voltage values and prevents high-frequency common-mode voltage, improving efficiency and reducing switch requirements, especially in step-up and step-down configurations.
Implementation Method 1
each piezoelectric assembly comprising at least one piezoelectric element; The switches of the first and second switching bridges are controlled cyclically, at the main oscillation frequency of the piezoelectric assemblies around their preselected resonance mode
Implementation Method 2
Piezoelectric DC-DC converters with temporary energy storage in mechanical form; in phases at substantially constant charge, the piezoelectric assemblies being in open circuit via the opening of at least one switch
Data Source
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AI summary
This converter (10) of an input voltage (Vin) into at least one output voltage (Vout) comprises a pair of first (12A) and second (12B) piezoelectric assemblies; a first bridge (30) having two first switching branches (32), each having at least one first switch (36); a second bridge (40) having two second switching branches (42), each having at least one second switch (46); each piezoelectric assembly having a first end (16) connected to the first bridge and a second end (18) connected to the second bridge; each first switch being connected between a terminal (34) of the input voltage and a first end; each second switch being connected between a terminal (44) of the output voltage and a second end. It comprises at least one additional switch (28) connected directly between the ends of a pair of piezoelectric assemblies connected to the same bridge.