Priority flow divider valve and its dynamic analysis using various hydraulic drive systems: a bond graph approach

This paper presents a new concept for calculating of the bond graph observer gains based on a graphical approach that investigates the Lyapunov Second Method in order to conclude about the observer stability and to search for the adequate gains that stabilize the observer. This new observer is used in the mode identification procedure. In fact, the observer’s residues allow the differentiation between the current mode and the other system modes. In order to guarantee the efficiency of the mode identification procedure, a new bond graph approach is proposed. It concerns the discernibility between the modes in bond graph language. First, it deals with the R-discernibility that introduces the definition of the discernibility through the structural parity residual then returns to a simple calculation of some matrices’ ranks in bond graph language. Second, another bond graph technique is applied to define the discernibility throughout the equivalency between the realizations.

Dynamics of a class of repeated systems with non-identical elastic and visco-elastic interconnections—a bond graph approach

Electric Power Steering (EPS) systems have many merits over traditional hydraulic power steering systems in fuel economy, variable assist capabilities and favorable road feeling by virtue of adjustment assist characteristic with adopting assist motor in replacement of hydraulic pump. This paper aims at modeling the mechanical parts, the assist motor and electronic control unit by bond graph technique and simulating system dynamic performance regarding vehicle maneuverability and stability and driver’s steering feel by Matlab/Simulink. The simulation results provide that the bond graph EPS model can reflect stability and dynamic steering characteristic in effect.

Problem statement: Further to research works made previously and which use collectively the scattering formalism and bond graph technique for the modeling of a physical systems often working in high frequencies, we propose, in this article, a comparative study (discussion) for the scattering matrix realization of a high-frequency physical system. Approach: This discussion is based, on the one hand, on a non-causal (acausal) bond graph model which represents the starting model for the determination of the scattering parameters. On the other hand, we shall use a causal bond graph model richer in information and to which we shall apply what we called in former articles: the analytical procedure of the scattering parameters exploitation with the aim of showing the importance of the causality notion in the physical systems study by the bond graph approach, as well as the importance of the ways and causal loops notion. Results: We will, initially, apply this discussion, to an elementary transmission line; in the second place, the application is carried out on the equivalent circuit of a band pass filter based on localized elements often used like microwave filters in high frequencies studies. Conclusion: We will finish this discussion by realizing the scattering bond graph model of a quadruple by pointing out the procedure used for the construction of this new type of bond graph model.

A hydrostatic drivetrain transmits wind turbine energy to a generator. One hydrostatic transmission system (HTS) configuration utilizes a fixed displacement pump and a variable displacement motor. The system dynamics are captured in a nonlinear multi‐input multi‐output mathematical model. This paper introduces a decentralized control configuration based on this model to achieve two desired objectives: maximizing the harvested energy without direct measurement of wind and regulating the frequency of the generator without using power electronic converters. To accomplish these objectives, suitable pairing of control actuators and system responses are identified through nonlinear relative gain arrays (RGA) analysis. The pairing also provides a strong decoupling of control loops. So maximum power point tracking (MPPT) is achieved independently while the generator speed is regulated to maintain the frequency of generated power at 60 Hz. Simulation results demonstrate robust performance of MPPT and frequency regulation in the presence of uncertainties in the turbine and HTS model. We also demonstrate that the RGA paired input‐out control configuration offers superior performance over other possible input–output paired control configurations.

This is the first part of a two-part paper developing a procedure for impedance synthesis and dynamic system conceptual design using a bond graph approach. The first part examines impedance synthesis with bond graphs and develops some useful properties of impedance related to bond graph structure. The second part of the paper uses the impedance synthesis approach as a tool in conceptual design for generating dynamic system solutions meeting frequency domain input-output specifications. In Part I, impedance and transfer functions are directly formulated from bond graphs. An invertible procedure is developed in order to allow for synthesis. Frequency domain properties of bond graphs are developed that will aid in impedance synthesis and the synthesis of bond graph structures from impedance specifications is formulated with a view toward conceptual design. The synthesis is not unique, a given impedance can be synthesized into multiple bond graph structures depending on its complexity. The work presented focuses on the synthesis of passive impedances but may be generalized for active systems.

2-Level-converters with 1700V-IGBTs and 1100V dc-link voltage are common in wind power generation. However, this dc-link voltage is not sufficient to fulfill reactive power requirements of grid operators in any circumstances. In case of high active and reactive power generation of the wind power plant and an overvoltage in the grid the dc-link voltage has to be increased. In this paper the power losses of a 2-level-converter with a fictitious 2kV-IGBT and a 3-level-converter with 1200V-IGBTs are calculated for 1250V dc-link voltage and compared to each other. The loss calculation is done over a wind speed range from 0 to 12m/s. Additionally the converter energy losses in 20 years are determined assuming a IEC III wind speed distribution. It was found that the 2-level-converter with 2kV-IGBTs produces the highest power losses in any operation points. The losses with the 1200V-IGBT 3-level-converter and 1250V dc-link voltage are even smaller than for the 2-level-converter with 1700V-IGBT and 1100V dc-link voltage. The values for the 20 years energy losses are corresponding. Therefore it can be said that the 3-level-converter is a good alternative to the 2-level-converter with 1700V-IGBT due to reduced power losses and the capability to fulfill grid code requirements.

In this paper, a simplified model of the NREL 5MW wind turbine with a hydrostatic transmission is derived. A suitable control scheme is described, and the steady state operating points of the system are calculated. The system is given in extended linearised form, and this form is used to design a gain scheduled linear quadratic regulator (LQR), with wind speed and difference pressure as scheduling parameters. Steady state operating points are used as desired values for feedforward control, and disturbance compensation is implemented to minimise the influence of rotor torque variations. Wind turbines operate in different control modes, with different control objectives which are dependent on wind speed. The developed controller is designed to operate for the entire operational range of the wind turbine. The controller is validated through simulation over a range of wind speeds.

Improving the reliability and energy production of large wind turbine with a digital hydrostatic drivetrain

In the years of 2014 until 2015 Pesangaran plant capacity undergo changes due to the expiration of employment contract lease diesel units and also the addition of new plant unit of 200 MW PLTMG. An increase or reduction in plant capacity of electrical system Bali will lead to significant changes to the load flow, power losses and energy losses in the circuit of Bali electrical Transmission system. Load flow analysis and power losses in Bali electricity system is simulated in five scenarios. Scenario 1 for the conditions of existing in 2014, scenario 2 is currently experiencing a reduction Pesanggaran plant capacity in December 2014, scenario 3 is currently experiencing Pesanggaran plant capacity additions in 2015 by using a peak load of 2014, scenario 4 is the scenario 3 with using predicted peak load in 2015, and scenario 5 is the scenario 4 with assuming the Celukan Bawang plant operates at 130 MW. Based on the results obtained by analysis, scenario 2 has the most power and energy loss about 46.34 MW and 300.39 GWh. For the loss of power and energy Bali electrical systems after Pesanggaran plants changes in 2015 are 38.57 MW and 250.05 GWh.

The worldwide increasing demand for electricity, coupled with governmental policy changes for green energy has led to significant interest in distributed generation (DG). Integrating DG into an electricity network, especially close to load centres, has many significant benefits but also brings with it many drawbacks such as voltage drop, and power losses. In this paper the impact of three different types of distributed generation (diesel generator, wind turbine and photovoltaic (PV)) on distribution networks' voltage profile and power losses is studied. NEPLAN software and the extended Newton-Raphson method have been used in the analysis. The obtained results show that different types of DG influence differently the distribution network and that their precise location and size are vital in reducing power losses and improving the voltage stability.

Transmission of electrical power from the generator to the load is a very important part of the electric power system. In the transmission system, it is necessary to increase the voltage to minimize power losses. The transmission system commonly used is High Voltage Alternating Current (HVAC). However, in reality the HVAC system can cause large losses. There are other transmission systems besides HVAC, namely High Voltage Direct Current (HVDC). The purpose of this paper is to compare the performance of HVAC and HVDC transmission systems in distributing electricity to variations in transmission distance or conductor line length and transmission voltage variations. The performance of the HVDC and HVAC systems measured is the power losses in the line conductors. In addition, power losses in transformer 1, transformer 2, and active power in HVAC. In addition, power losses at station 1, station 2, and active power at HVDC. The type of power plant used in this paper is renewable energy. The renewable energy consists of photovoltaic and wind power plants. The results for very long transmission distances, HVDC has smaller power losses than HVAC. In addition, HVDC stations have higher power losses than HVAC transformers. Based on the total power losses, overall the total power losses in HVDC is smaller than the total power losses in HVAC.

<div class="htmlview paragraph">A series of examples, involving normal mode representations of a flexible railcar and various suspension models, is presented illustrating the use of bond graph techniques for assembling a structural dynamic system model from component models. Bond graph techniques are related to other methods for achieving the same goal, and the unique features of bond graph techniques are pointed out. Not only does the bond graph provide a graphical representation of the organized system equations, but also it allows the use of ENPORT programs for automating the process of manipulating the component relations into an explicit-state space format suitable for simulation or analysis. Nonlinear and active systems which interact with structural dynamic components are readily handled using bond graph techniques.</div>

Online secondary path modeling algorithm without auxiliary noise for narrowband active noise control

Bond graphs provide an energy-based methodology for modelling complex systems hierarchically; at the moment, the method allows biological systems with both chemical and electrical subsystems to be modelled. Herein, the bond graph approach is extended to include chemomechanical transduction thus extending the range of biological systems to be modelled. Actin filament polymerization and force generation is used as an example of chemomechanical transduction, and it is shown that the TF (transformer) bond graph component provides a practical, and conceptually simple, alternative to the Brownian ratchet approach of Peskin, Odell, Oster and Mogilner. Furthermore, it is shown that the bond graph approach leads to the same equation as the Brownian ratchet approach in the simplest case. The approach is illustrated by showing that flexibility and non-normal incidence can be modelled by simply adding additional bond graph components and that compliance leads to non-convexity of the force-velocity curve. Energy flows are fundamental to life; for this reason, the energy-based approach is utilized to investigate the power transmission by the actin filament and its corresponding efficiency. The bond graph model is fitted to experimental data by adjusting the model physical parameters.