Yasuharu Ohsawa's research while affiliated with Kyoto University and other places
What is this page?
This page lists the scientific contributions of an author, who either does not have a ResearchGate profile, or has not yet added these contributions to their profile.
It was automatically created by ResearchGate to create a record of this author's body of work. We create such pages to advance our goal of creating and maintaining the most comprehensive scientific repository possible. In doing so, we process publicly available (personal) data relating to the author as a member of the scientific community.
If you're a ResearchGate member, you can follow this page to keep up with this author's work.
If you are this author, and you don't want us to display this page anymore, please let us know.
It was automatically created by ResearchGate to create a record of this author's body of work. We create such pages to advance our goal of creating and maintaining the most comprehensive scientific repository possible. In doing so, we process publicly available (personal) data relating to the author as a member of the scientific community.
If you're a ResearchGate member, you can follow this page to keep up with this author's work.
If you are this author, and you don't want us to display this page anymore, please let us know.
Publications (15)
Energy storage devices are necessary to address the issues associated with stochastic variation of generated power in a wind energy conversion system. This study explores the control and operational aspects of integrating a smart energy storage system (SESS) into a double-fed induction generator-based wind power system. The fuel-cell/electrolyser s...
This paper explores the control and operational aspects of integrating a short- and long-term storage mix, known as smart energy storage system (SESS), into a cage induction generator based wind power system. Embedding such an SESS with wind power system not only provides the solution for intermittency but also makes the system dispatchable. The fu...
This paper explores the control and operational aspects of introducing fuel cell/electrolyzer/ultracapacitor (FC/ELZ/UC) unit into a microhydro power system, replacing the conventional electronic load controller/dump-load unit. FC/ELZ is expected to provide long-term energy balance by utilizing the hydrogen technology, whereas the UC is employed as...
This paper deals with factors affecting the charging characteristics of insulators exposed to high voltages in vacuum. We examined the influence of voltage shape on charging. The charging was studied by using an electrostatic probe that measured electric field on the cathode. A ramped dc and an impulse voltage were tested in a low pressure and foun...
This paper proposes the control scheme for an AC-linked hybrid wind/fuel cell/ultracapacitor alternative energy system for a stand-alone operation. Due to the intermittent nature of power obtained from the wind turbine-generator system, Hydrogen/fuelcell(H<sub>2</sub>/FC) and ultracapacitor(UC)are introduced as main storage and buffer storage respe...
Modeling single-machine (synchronous-generator) infinite-bus (SMIB) systems with what we call the improved swing equations is considered in this paper. The existence and properties of local solutions to the improved swing equations are then examined. Furthermore, the local stability of the SMIB systems is scrutinized. By interpreting the improved s...
This paper explores the active and reactive power sharing scheme for the parallel operation of inverter interfaced distributed generators (DGs) in a microgrid system. Applicability of conventional wireless control technique, based on P-f and Q-V droop regulations, is also investigated for the load sharing among the DGs with the help of small signal...
This paper deals with charging characteristics of the inner surface of an insulating hollow cylinder in vacuum. We conducted measurements of electric field strength near the triple points on cathode by using an electrostatic probe. Also we conducted a computer simulation of charging based on the Secondary Electron Emission Avalanche (SEEA) mechanis...
This paper deals with factors affecting the charging characteristics of insulators exposed to high voltages in vacuum. We examined the influence of voltage shape on charging. A ramped dc and impulse voltages were tested in a low pressure and found that the amount of charge was larger for the impulse voltage than that for dc voltage. We also examine...
Stabilization in multimachine (synchronous generators) power systems is dealt with through a class of decentralized and nonlinear state feedback laws that can be separately designed in a generator-wise fashion, based on what we call the improved swing equations. Stability of the closed-loop power systems is robust with regard to perturbations in el...
Several upper and/or lower bounds to nodal voltage variations are derived in this paper, by exploiting what we call the Hermitian power equations of power systems. Bound inequalities are established for nodal voltage variations in terms of singular values of structural characteristics of power systems, which are running at steady-state equilibria a...
In this paper, some interesting inequalities about nodal voltage variations are established, by working on what we call the Hermitian power equations of power systems. These inequalities give lower and/or upper bounds for nodal voltage variations by means of singular value evaluations related to structural characteristics of power systems, at opera...
The present paper is concerned with stabilization of a power system with WPGS (wind power generation system) by active power control of a number of micro SMES units. The sample power system for simulation includes three hydro power stations including two pumped storage stations, two wind power generation stations and long transmission lines. Wind v...
In this study we formulate the power equations of power systems that are operating in their steady states into what we call the dtic and Hermitian power equations in terms of nodal active/reactive powers. These quadratic and Hermitian power equations are then generalized in terms of active/reactive power indices, based on which we complete three ta...
In this paper, a novel algorithm for power flow computations is developed by com-bining the well-known Newton-Raphson method with the particle swarm optimization technique, through what we call the Hermitian power equations of power systems. Convergence conditions and convergence rates of the suggested algorithm are also examined. Compared with con...
Citations
... n is the number count of the DG units. Meanwhile, the DG unit ratings and operating conditions, as well as minimal voltage variations must be considered when tuning the droop gradient coefficient [62], [83]- [85]. In addition to the various alternative projects being executed by the SAG, it recently embarked on supporting the implementation of some microgrid projects with innovative solutions with relative success. ...
... According to SEEA theory, the flashover is strongly affected by surface charge on solid dielectrics resulting from secondary electron emission (SEE). The surface charging has attracted more and more attention of the researchers [8][9][10][11][12][13]. Yamamoto found that the amount of accumulated surface charges was larger for impulse voltage than that for a ramped DC voltage [9]. ...
... The battery package is an interesting option for storing excess energy from the hybrid grid (wind intermittency) for later use. It may also act as a peak shaving unit and thereby contribute to a stronger grid111213. The propose of the energy storage system is to be coupled with a wind generation system in order to realize different tasks, such as: to have the generation output power smoothed and to grant no power transfer, for a certain period on distribution system operator request, at a point of common coupling (PCC) in any battery state of charge condition. ...
... The application of HESS in FR is investigated in a number of studies in literature [167][168][169][170][171]. The main challenge in HESS is the control of power output of the storage units. ...
... As shown in Figure 5 (top panel), all these approaches are evenly addressed in the literature, with a dominance of dynamical system models, most probably due to its direct connection to single-node dynamics, based on the balance between mechanical and electrical power, described through the so-called swing equation [159,160]. We note that modern AI approaches within reservoir computing seem to be not so ubiquitous in the context of power grid research, showing one possible avenue to be more intensely investigated in future research (see also the absolute number of articles in our bibliography shown in Figure 5 covering each type of modeling approach). ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/278895208222728-1443505207655_Q64/Jun-Zhou-17.jpg)
... They provide a stable balance between supply and demand in the long and short term [4]. Opposite to this traditional energy system fed by fossil fuels, appears through power-to-hydrogen (Pth), the future renewable energy system that pretends to be relevant to sector coupling and grid balancing [5][6][7][8]. This affirmation is thanks to the current technological level of hydrogen production, which has created the opportunity to use it as a fuel for gas turbines and fuel cell systems for power generation [9,10]. ...
... For this purpose, a dual magnet type SMES is more effective though AC loss increases for high operating current. SMES also enhances transient and dynamic stabilities of power grid integrated with WPGS at faulty conditions [84][85][86][87][88][89]. To stabilize a grid connected WPGS a FL control method is very useful. ...
