Hydraulic Energy Conversion Research Articles

Research on Design Method of the Hydraulic Energy Conversion System of Inertial Wave-energy-powered Buoy

Research on Design Method of the Hydraulic Energy Conversion System of Inertial Wave-energy-powered Buoy

Hardware–In–The–Loop Assessment of Robust Fuzzy Control Solutions for Hydroelectric and Wind Turbine Models

The interest towards renewable energy resources is increasing, and in particular it concerns wind and hydro powers, where the key point regards their efficient conversion into electric energy. To this end, control techniques can be used to meet this purpose, especially the ones relying on fuzzy models, due to their capabilities to manage nonlinear dynamic processes working in different conditions, and affected by faults, measurement errors, uncertainty and disturbances. The design methods addressed in this paper were already developed and validated for wind turbine plants, and important results can be achieved from their appropriate design and application to hydroelectric plants. This is the key issue of the paper, which recalls some considerations on the proposed solutions, as well as their validation to these energy conversion systems. Note that works available in the related literature that consider both wind and hydraulic energy conversion systems investigate a limited number of common issues, thus leading to little exchange opportunities and reduced common research aspects. Another important point addressed in the paper is that the proposed control design solutions are able to take into account the different working conditions of these power plants. Moreover, faults, uncertainty, disturbance and model-reality mismatch effects are also considered when analyzing the reliability and robustness features of the derived control schemes. To this end, proper hardware-in-the-loop tools are considered to verify and validate the developed control schemes in more realistic environments.

Analysis of a novel energy-efficient system with 3-D vertical structure for hydraulic press

A hydraulic press is a closed energy-conversion system comprising electric energy, mechanical energy, hydraulic energy, and deformation energy. In this system, the energy losses among multiple energy-conversion processes are significant, particularly in the hydraulic energy conversion, resulting in low energy efficiency. To address this issue, this study proposes a three-dimensional vertical arrangement for a hydraulic press that reduces energy dissipation and improves the energy efficiency of the system. In this structure, the space above and below the ground is used comprehensively and the hydraulic equipment are arranged sequentially in vertical layers. Some equipment are connected directly to minimize the use of valves and pipelines; this reduces the transmission distance of hydraulic energy between the pump station and the actuator, as well as the number of control valves. Furthermore, an energy-saving buffering device was installed at the top layer of the structure to absorb pressure fluctuations and reduce structural oscillations. As a case study, the proposed structure was applied to a 35-MN hydraulic press. The results of theoretical calculations, simulations, and comparative experiments indicate that, when using the proposed system, the energy efficiency of the press could be improved by 20.0% and the average energy consumption of the pipeline-valve system could be reduced by 65%.

Design and performance analysis of human walking induced energy recovery system by means of hydraulic energy conversion and storage

Human walking induces a lot of mechanical energy available for harvesting. It is promising to use such energy to reduce the energy supply of wearable electronics and robotic equipment such as exoskeleton. This paper mainly deals with the design and performance analysis of the energy recovery system based on fluid power transmission principle. Firstly, modeling and simulation of single foot walking motion were carried out to investigate the human walking dynamics to explore the variation of energy produced by human walking within a gait cycle. Together with gait characteristics measurement, the foot-ground interaction force in the horizontal and vertical directions is obtained. Then, the energy recovery system based on the working principle of volumetric pump was designed to convert the human walking induced mechanical energy into hydraulic energy directly and achieve energy storage with accumulator in the meantime. The energy recovery results obtained under different conditions of walking speed and load carrying are considered by numerical simulation and experimental verification. It is shown that the output power in average of the recovery mechanism by single foot walking at 5.56 km/h is around 3.2 W, and the captured power can be increased with higher precharge pressure of accumulator. Comparisons indicate that power and its density of the system proposed in this paper are far greater than that achieved by electric generation, providing a potential solution for hydraulically actuated walking mechatronic systems.

Low power experimental prototype of a controlled three-phase inverter using D.S.P (TMS320F2812) for a hydraulic energy conversion chain application

This paper deals with a part implementation of the distributed generation chain system based on hydraulic power source operated in low power and controlled by DSP F2812. The experimental part of the chain includes a controlled two-level three-phase inverter connected, via an LC filter, to a load. This latter consists of a balanced three-phase resistive without neutral point joint, for this reason, the implementation requires fewer sensors as measuring devices. The proposed control strategy uses just two regulation loops; one of them is for the AC output voltages and the other one is for the input inductor currents of LC filter. This strategy was developed on Matlab-Simulink and implemented in eZdsp TMS320F2812 DSP board from spectrum digital. To confirm the efficiency and robustness of the chain part implementation, the experimental results using the implemented inverter was compared with a compact industrial module 7MBR15SA120 inverter mounting with the same control interface and measurement cards. The experimental waveforms comparison prove that there is a good match between the two practice prototypes, validate the theoretical study as well as the simulation results obtained and confirm the effectiveness of the proposed control strategy.

Low power experimental prototype of a controlled three-phase inverter using D.S.P (TMS320F2812) for a hydraulic energy conversion chain application

This paper deals with a part implementation of the distributed generation chain system based on hydraulic power source operated in low power and controlled by DSP F2812. The experimental part of the chain includes a controlled two-level three-phase inverter connected, via an LC filter, to a load. This latter consists of a balanced three-phase resistive without neutral point joint, for this reason, the implementation requires fewer sensors as measuring devices. The proposed control strategy uses just two regulation loops; one of them is for the AC output voltages and the other one is for the input inductor currents of LC filter. This strategy was developed on Matlab-Simulink and implemented in eZdsp TMS320F2812 DSP board from spectrum digital. To confirm the efficiency and robustness of the chain part implementation, the experimental results using the implemented inverter was compared with a compact industrial module 7MBR15SA120 inverter mounting with the same control interface and measurement cards. The experimental waveforms comparison prove that there is a good match between the two practice prototypes, validate the theoretical study as well as the simulation results obtained and confirm the effectiveness of the proposed control strategy.

Some Aspects Regarding Torque Study and Elaboration of the Blades Orientation Mechanism for Microhydropower Plant

The analysis of hydraulic energy conversion systems has demonstrated the opportunity for the development of water kinetic energy conversion systems compared to potential energy conversion systems. Insistent searches of authors have led to the design and licensing of some advanced technical solutions for outflow micro hydroelectric power plants. They are based on the hydrodynamic effect, generated by the hydrodynamic profile of blades and by the optimal blades' orientation towards water streams with account of energy conversion at each rotation phase of the turbine rotor. The basic advantage of the flow microhydropower plant is the increase of the conversion efficiency by the simultaneous use of the pressure effects of water streams on the blade surface and of the hydrodynamic effect generated by the hydrodynamic profile of the blade with continuous blade orientation. The most important nodes of the microhydropower plant are the hydrodynamic rotor with vertical axis and the mechanism of continuous orientation of the blades depending on the direction of water currents. The paper makes an analysis of the brief torque and of the forces applied on the hydrodynamic blades located in the transition zone from the upstream area to the downstream area, by positioning the blades according to the flow velocity of the water flow which leads to increased hydrodynamics forces developed by each blade and the simultaneous reduction of the hydraulic resistance forces to the rotation of the blades, based on which the mechanism of orienting the blades in optimal positions against water currents was designed, developed, and manufactured.

A Typical Topology of Boost Converter for Improving Efficiency of Hydraulic Energy Conversion chain

A Typical Topology of Boost Converter for Improving Efficiency of Hydraulic Energy Conversion chain

Experimental validation of an analytical model of hydraulic motor operating under variable electrical loads and pressure heads

The objective of this work is the development of an analytical model for a hydraulic motor by using the hydraulic resistance concept. The developed model integrates the whole Hydro-Mechanic-Electric-Conversion (HMEC) line. Currently, the HMEC line represents an important technological challenge since it impacts strongly the overall efficiency of hydraulic energy conversion systems that operate under variable flow rate or pressure heads. Among these systems, we can mention wave energy converters, hydraulic systems as well as the innovative thermo-hydraulic CAPILI process based on liquid piston concept that has been recently developed in PROMES Lab.The paper describes the analytical model developed for the hydraulic motor, taking into account the main parameters of the HMEC conversion line. A small scale experimental bench of HMEC line operating under highly variable conditions has been implemented. The experimental results allowed the validation of the analytical model and the identification of the different characteristics of the HMEC line which takes into account the coupling efficiency and both volumetric and mechanical efficiencies of the hydraulic motor. Herein, the relevance of this hydraulic resistance based-model is highlighted, more specifically through the power output regulation systems and also for the optimisation of the thermo-hydraulic energy conversion systems based on liquid piston concept.

Electrokinetic Energy Conversion in Self-Assembled 2D Nanofluidic Channels with Janus Nanobuilding Blocks.

Inspired by the microstructure of nacre, material design, and large-scale integration of artificial nanofluidic devices step into a completely new stage, termed 2D nanofluidics, in which mass and charge transportation are confined in the interstitial space between reconstructed 2D nanomaterials. However, all the existing 2D nanofluidic systems are reconstituted from homogeneous nanobuilding blocks. Herein, this paper reports the bottom-up construction of 2D nanofluidic materials with kaolinite-based Janus nanobuilding blocks, and demonstrates two types of electrokinetic energy conversion through the network of 2D nanochannels. Being different from previous 2D nanofluidic systems, two distinct types of sub-nanometer- and nanometer-wide fluidic channels of about 6.8 and 13.8 Å are identified in the reconstructed kaolinite membranes (RKM), showing prominent surface-governed ion transport behaviors and nearly perfect cation-selectivity. The RKMs exhibit superior capability in osmotic and hydraulic energy conversion, compared to graphene-based membranes. The mineral-based 2D nanofluidic system opens up a new avenue to self-assemble asymmetric 2D nanomaterials for energy, environmental, and healthcare applications.

Hydraulic Hybrid Propulsion for Heavy Vehicles: Combining the Simulation and Engine-In-the-Loop Techniques to Maximize the Fuel Economy and Emission Benefits

The global energy situation, the dependence of the transportation sector on fossil fuels, and a need for a rapid response to the global warming challenge, provide a strong impetus for development of fuel efficient vehicle propulsion. The task is particularly challenging in the case of trucks due to severe weight/size constraints. Hybridization is the only approach offering significant breakthroughs in near and mid-term. In particular, the series configuration decouples the engine from the wheels and allows full flexibility in controlling the engine operation, while the hydraulic energy conversion and storage provides exceptional power density and efficiency. The challenge stems from a relatively low energy density of the hydraulic accumulator. This places particular emphasis on development of the supervisory controller. The conventional wisdom is to operate the engine at the “sweet spot”, but the aggressive pursuit of engine efficiency as the sole objective can lead to frequent and rapid diesel engine transients, thus causing an adverse affect on the soot emissions and driver feel. Therefore, we propose a comprehensive methodology for considering a combined hybrid system fuel-economy and emissions objective. The fuel economy is addressed with the simulation-based approach, while investigating the impact of engine transients on particulate emission relies on the Engine-In-the-loop (EIL) capability. The EIL study confirms advantages of a modulated state-of-charge control over the thermostatic approach, and demonstrates the ability of the Series Hydraulic Hybrid to improve the fuel economy of the medium truck by 72%, while reducing the particulate emission by 74% compared to the conventional baseline over the city driving schedule.

Integration of Electromagnetic Technologies Into Shipboard Applications

Technical progress has led to the ability to manipulate energy transfer such that prior ship applications using mechanical or hydraulic energy conversion can often be replaced by more reliable and efficient electromechanical methods. This paper reviews recent developments in electric propulsion motors and integrated power systems for ships. Examples are given for cruise ships, cargo ships and special applications like ice breakers and oceanographic exploration. Emerging technologies are described, for example, superconducting propulsion motors, superconducting bus, fuel cells, and autonomous unmanned vehicles for oceanographic mapping and studies