Interleaved Piezo Pump Drive Circuit Phase Balancing
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Solution Overview
Problem
Existing piezo-electric fluid pump systems for aircraft hydraulic systems face challenges in achieving sufficient pressure and flow capability to compete with traditional electro-hydraulic actuators, while also dealing with weight and component count issues.
Innovation Solution
A drive circuit for a plurality of piezo-actuated hydraulic pumps is developed, featuring a voltage boost stage, parallel inverter stages, and a control system that balances power consumption and adjusts phase to optimize performance. This configuration reduces peak power demand, allows for passive component reduction, and enhances power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple piezo pumps are operated in phase, then each pump can be driven independently, but the peak power demand at the coupled point increases significantly
Solution Approach 1:
The patent applies periodic action by operating multiple piezo pumps out of phase with each other, where each pump is driven at a different phase angle (e.g., 0°, 120°, 240° for three pumps). This periodic phasing ensures that when one pump draws peak current, another pump is in a lower current phase, thereby distributing the peak power demand over time and reducing the instantaneous peak power requirement at the coupled point.
2Reliability
If passive circuit components are sized for peak power demand, then they can handle maximum loads, but the overall mass and volume of the electronics increase
Solution Approach 1:
The patent applies dynamics by transitioning from static component sizing based on peak power demand to dynamic power distribution through phase control. By actively managing the temporal distribution of power demand through phased operation, the system allows passive components to be sized for lower, average power levels rather than peak levels, thereby reducing component mass while maintaining reliability through intelligent control.
3Power
If the boost stage is rated for peak power, then it can supply maximum power to all pumps simultaneously, but the power density and efficiency decrease
Solution Approach 1:
The patent applies continuity of useful action by ensuring that at least one piezo pump is always in a phase where it is drawing useful power, rather than allowing simultaneous peak draws from all pumps. The phased operation creates a continuous, more uniform power demand pattern on the boost stage, allowing it to be rated for lower continuous power levels while maintaining the ability to supply maximum power when needed, thereby improving power density and reducing energy losses.
4Device complexity
If a centralized hydraulic pump system is used, then system simplicity is maintained, but the number of pipes and valves increases cost and complexity
Solution Approach 1:
The patent applies segmentation by dividing the single centralized hydraulic pump into multiple independent piezo pumps, each capable of serving its own hydraulic actuator. This segmentation eliminates the need for complex piping networks and valves that would be required to distribute fluid from a single centralized pump to multiple actuators, thereby reducing the quantity of pipes and valves while maintaining system functionality.
5Adaptability or versatility
If separate motor and pump components are used in EHA, then design flexibility is maintained, but weight and component count increase
Solution Approach 1:
The patent applies merging by integrating the piezoelectric pump and motor functions into a single unified piezo-actuated pump assembly. The piezoelectric elements directly drive the pump mechanism without requiring separate motors, thereby eliminating the weight and space of separate motor components while maintaining design flexibility through electronic control of the piezoelectric elements.
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 achieves significantly increased pump output with reduced size and weight, improved power density, and increased drive efficiency, while also providing fault tolerance and cost reduction through shared power electronics.
Implementation Method 1
piezo-actuated hydraulic pumps
Data Source
AI summary
A drive circuit for a plurality of piezo-actuated hydraulic pumps for an aircraft, and a hydraulic pump system implementing the same. The drive circuit includes a voltage boost stage that receives a DC input supply voltage and delivers an increased DC output voltage to a high voltage, HV, link point; a plurality of inverter stages coupled in parallel at the HV link point that receive DC voltage from the HV link point and generate an oscillating output voltage for driving a respective piezo-actuated pump; and a control system that controls the output voltage and phase of the inverter stages to drive the plurality of piezo-actuated pumps out of phase. The control system measures the power consumption of each piezo-actuated pump and regulates the output voltage of at least one of the inverter stages to balance the power consumption of each piezo-actuated pump.