The Green Rotorcraft research Consortium of Clean Sky (CS-GRC) requested the development of a Piezo Power Supply module (PPS) and the associated Man Machine Interface (MMI).
CEDRAT (coordinator, SME) and UJF-G2ELAB (partner, lab from Grenoble Joseph Fourier University) formed a consortium using their shared experience on piezoelectric actuators and high efficiency high power supplies to meet the GRC request by the PPSMPAB project.
The PPSMPAB project aimed at developing 2 PPS offering the highest required power (16kVA) with a high efficiency, for driving piezo actuators, accounting for further helicopter applications.
The proposed development split the need into 3 main items: The preferred DC-DC converter providing the DC sources would be an isolated full bridge resonant converter, with adjustable bus DC voltage. The DC-AC 2-channels switching amplifier will provide the 2x8kVA power with adjustable output voltage range. The preferred approach is today a full bridge offering bipolar output. For highest targeted voltages, multilevel amplifiers will be considered. The MMI will combine a digital platform and associate software, preferred one being Labview Real-Time RIO.
For the PPSMPAB project, CEDRAT and UJF-G2ELAB proposed the following WBS:
- WP1 - Management: CEDRAT will perform a technical, contractual and financial administration of the project and will guarantee the objectives and deadline complying.
- WP2 - Design concept & architecture: UJF-G2ELAB will analyse electronic architectures (several being identified in the proposal) and technologies (MOSFET vs IGBT) and will present the results in form of trade-off, allowing the GRC Consortium to select the one to develop.
- WP3 - Detailed design & manufacturing: CEDRAT will perform the PPSM detailed design and manufacture two prototypes.
- WP4 - System validation tests: CEDRAT will perform requested tests on PAB and EDS benches and provide both support and the final report with recommendations on PPS modules.
The development of the helicopters market is today limited because of their strong impact on the environment. Their fuel consumption is high and produces a lot of emission; they generate a lot of noise both for the passengers (cabin noise) and for the people living close to the heliports (external noise). The main source of this inconvenience is due to the main rotor, especially its blades, which presently cannot dynamically adapt their aerodynamic profile to the desirable one. The consequence is a strong level of vibrations and noises from the rotor, such as Blade-vortex interaction (BVI) noise, also called “blade slap”. This is especially in the cases of fast forward and descent flights. Other impacts of the inability of rotor blades to adapt their aerodynamic profiles to flight conditions are limited performance regarding flight envelope, speed, and range.
However, because of present material and technological limitations, an ideal real-time adaption of the blade shape is not possible and several different options have been considered, including:
- The rotation of the blade, performed by actuating the rotor blade root
- The all-movable blade tip, driven in rotational motion by an induced-strain rotary actuator placed inside the blade.
- The twist of the blade, performed by distributed actuators along the blade
- The morphing of the blade cross section, performed by local actuators at the blade extremity:
- Actuating by articulation trailing edge flaps, leading edge flaps or bumps, or seamlessly deforming a part of the structure cross section for such functions.
Another completely different approach relies on the use of synthetic jets located along the blade surface, blowing or sucking air flow to generate turbulences allowing the boundary layer to stick on the blade surface. These jets can be produced by micro or miniature actuators located in cavities inside the blade and pulsating air by small holes on the blade surface.
In this context, the piezo technology seemed to be a good candidate for actuators and the Green Rotorcraft research Consortium of Clean Sky (CS-GRC) requested the development of a Piezo Power Supply module (PPS) to drive these powerful actuators. CEDRAT-TECHNOLOGIES (coordinator, SME) and UJF-G2ELAB (partner, lab from Grenoble Joseph Fourier University) formed a Consortium using their shared experience on piezoelectric actuators and high efficiency high power supplies to meet the GRC request by the PPSMPAB project.
The PPSMPAB project aimed at developing a PPS offering the highest required power (9kVA) with a high efficiency, for driving piezo actuators, accounting for further helicopter applications.
The proposed development split the need in 2 main items:
- The preferred DC-DC converter providing the DC sources would be an isolated full bridge resonant converter, with adjustable bus DC voltage to be interfaced with a +270VDC aeronautic bus
- The DC-AC 2-channels switching amplifier will provide the 2x4.5kVA power with adjustable output voltage range in a [-200+1000]V range following a specific frequency spectrum.
The development of such a solution has followed a feasibility study covered by some trades off and demonstrators of the power cores, a detailed design of the solution covering the electronic functions and the associated packaging in regards of the embedded application and the realisation of a prototype to answer to the initial demands.