Small Active Power Research Articles

Transmission network angle stability protectionbased on synchrophasor data in control centre

Angle stability appears in many forms in transmission network. There are small active power oscillations which do not endanger the normal operations whereas medium and large oscillations have implications on normal operations. These latter kinds of oscillations in some cases develop in out of step condition, which is dangerous disturbance with serious impact on transmission network and generating units. Transmission network operator’s challenges and obligations are to treat in the right manner angle stability issues in their network. Controlling and protecting network needs to be done in efficient way in order to disconnect disturbance quickly and prevent abnormal network operation without exporting disturbance in surrounding networks. Synchrophasor measurements in control centre offer a platform, which responds in a new way on angle stability in transmission network. Those measurements which are collected in phasor data concentrators, which is a part of Wide Area Monitoring will be used for creating out of step protection. This is the first step to extended system to Wide Area Monitoring Protecting And Control (WAMPAC). Paper gives progress of such project in Croatian Transmission Network Operator (HOPS). Firstly, there will be stated motives for development of new out of step protection based on synchrophasor measurements. Some feasibility aspect elaborated with emphasis on communications latency. Furthermore, designed Matlab model for transmission network and protection with small portions of simulations results and analyses presented in paper reveal potential of proposed solutions. This new protection is based on using voltage angles values from phasor data stream in phasor data concentrator.

Data-driven Structural Control of Monopile Wind Turbine Towers Based on Machine Learning

This paper studies the data-driven structural control of monopile wind turbine towers based on machine learning approach, by using an active tuned mass damper (TMD) located in the nacelle. The adaptive dynamic programming (ADP) approach is employed to obtain the optimal controller which is derived on the modern large-scale machine learning platform Tensorflow. The proposed network structure includes three simple three-layer neural networks (NNs), i.e. a plant network, a critic network, and an action network. The plant network is used to capture the fully nonlinear dynamics of the structural system while the action network is used to approximate the optimal controller. Their training requires the gradient information flowing through the whole network. The automatic differentiation is used in this paper for all the gradient derivations, which greatly improves the employed ADP algorithm’s ability in solving complex practical problems. The simulation results of structural control of monopile turbine towers show that on average the active TMD achieves 15% performance improvement on tower fatigue load reduction over a passive TMD, with small active power consumption (less than 0.24% of the turbine’s nominal power production). Besides, the controller design considers the trade-off between control performance and power consumption.

Model predictive control‐based smart impedance for harmonic load freewheeling

A novel smart impedance (SI) is introduced for load harmonics (distortion power) freewheeling in microgrids which are called predictive SI (PSI). ‘PSI’ provides solutions to the load harmonics conditioning, reactive power compensation, and parallel resonance suppression. The ‘PSI’ allows for harmonics, sub-harmonics, and inter-harmonics compensation with using only one control loop. The control model, which is used for the ‘PSI’ enables its impedance phasor variation in a wide and continuous range, including inductive and capacitive ones. The ‘PSI’ consumes small active power and can provide reactive power compensation without the need for a separate capacitor bank. The introduced ‘PSI’ does not generate parasitic harmonics and so does not need an additional passive filter in its output. The ‘PSI’ operates such as a harmonic isolator and only compensates for load harmonics and thereby prevents from the source side harmonics flowing into the load. It does not need the phased locked loop for synchronisation to the grid and can be designed for selective harmonic compensation if needed. A droop-boost control strategy is proposed for optimum and prioritised utilising of the SI capacity. At the end of the study, by using simulations in Matlab/Simulink, the figure of merits of the PSI are proved.

A novel partial transient active-reactive power coupling method for reactive power sharing

In this paper, a control strategy has been presented to improve the reactive power sharing among distributed generation units in the islanded microgrids. The proposed control method is based on exerting a partial transient coupling between active and reactive powers. This partial coupling is performed by adding a small reactive power droop term in the conventional frequency droop controller during the compensation time. This coupling term causes a small active power disturbance that used to generate a compensation voltage signal. The suggested compensation scheme is enabled by the synchronized flag signal through a low-bandwidth communication link. To assess the performance and effectiveness of the suggested control approach, a MG with three DGs is simulated. The simulation results demonstrate that the reactive power is shared among DGs accurately. Simplicity, no need for additional communication links, non-dependence on MG configuration and insignificant transient disturbances are the main advantages of the proposed method.

ACTIVE POWER MEASUREMENT ACCURACY INCREASING WITH SIGNIFICANT REACTIVE COMPONENT

The broadband wattmeter of transient power with its own consumption error correction for measuring the active power against the background of large reactive components in the frequency range up to units MHz is described in the article. This instrument can measure the power loss (active power) in a variety of reactive elements, for example, the inductances used in pulsed energy converters. Such wattmeter can be used to optimize the development of wireless power transmission systems based on open resonance circuits. The structure of such systems, as was found during the study, has a spherical directional pattern and does not depend on the emitter and receiver location, described in the article. The article specifies the features of active power measurements at searching for the most efficient design of wireless power transmission systems on the basis of open resonant circuits, where the measurement is complicated by the fact that relatively small active power needs to be measured against the background of large reactive components, when the operating frequencies are shifted from the resonance, and phase shift between current and voltage accrue.At high frequencies measuring, the channels of the wattmeter become very sensitive to phase errors. It is necessary to minimize links that cause phase shifts. In this connection, it is important to construct correctly the wattmeter input units and to make such a transformation, which will provide operations with signal modules. The proposed scheme allows this to be achieved, and required gain is carried out without taking into account the signals phase shift.In the basic scheme of the wattmeter, the input device is executed from the main shunt and parallel to the auxiliary distributed shunt connected to it, which is connected to the main resistance of the voltage divider, in which the value of all resistances of the input device is determined by conditions of invariance to the squares of the voltage and load current, and the partially distributed auxiliary shunt is calculated with additional weighting factors to provide the conditions for invariance of the square of voltage and current and eliminate the error from its own revives.The value of the calculated power measurement error on the model for this wattmeter is 0,1%. The basic error of the wattmeter is the error of the low-ohm shunt. It is expedient to use coaxial or triaxial shunts to extend the frequency range. The designs of such shunts and examples of shunts with the best technical characteristics for today are given in the article.The advantages of such wattmeter are:- gives the exact value of the measured power on the load, regardless of the actual consumption of the input device;- the values of the input device elements can be optimized by the criterion of maximum broadband, since the error from its own consumption is taken into account;- one low-level shunt, which reduces the cost of the wattmeter; is used in the scheme- additive errors of the voltage conversion channel are minimized.

Comprehensive synchronous reference frame discrete-time modelling of a grid-connected PV for fast DC-side voltage control

This paper presents a novel comprehensive discrete-time model of a three-phase single stage grid-connected photovoltaic generation system. The detailed model is carried out on synchronous reference frame. It is shown that both converter's AC and DC-side discrete time model differs from the continuous time one. The main differences are the AC-side current and voltage cross coupling, and the DC-side voltage non-minimum phase behaviour for small active power injected into the grid. Based on the new model, digital internal current and external DC-link voltage controllers are designed. Experimental results show that the proposed controllers provide fast transient response and disturbance rejection. Small errors obtained comparing experimental and simulation waveforms for both DC-side voltage and AC-side current corroborate to validate the model and the designed controllers.

A robust 18-pulse diode rectifier with coupled reactors

A robust 18-pulse diode rectifier with coupled reactorsThe article presents the principle of operation and selected results of simulation and laboratory tests of the 18-pulse rectifier system with coupled reactors and small series active power filter. The presented system makes it possible to reduce, especially in distribution supply networks, undesired higher current harmonics. The 18-pulse nature of operation of the rectifier is reached using a set of coupled three-phase network reactors (CDT and CTR). The simultaneous use of the coupled reactors and the small active power filter provides opportunities for reduction of the supply current distortion, especially in case of voltage harmonic distortion and voltage unbalance.

612 スポーツとロボットにおける巧みな動きの生成原理への構成論的アプローチ

There is no robot around us in our society at the current stage and also there will be no robot in the future if we define a robot as a machine working in the arena of offices, homes, and disaster sites, etc. outside the factories and if we continue the present conventional research and development style in robot projects. Also in sports, moving body parts around a fixed joint is very popular, but it seems to limit one's power, whereas more power can be generated and the strain on the body is lessen by using the entire body without twisting motion and not resorting to just the fixed joint. This paper proposed the approach for realization of robust physical movements based on distributed control of physical body in humanoid biped robots and in sports, which uses only small active power making full use of equilibrium instability as a source of driving force with simple state transition. Making postures simultaneously by using the entire body produces natural movements. It can be applied to movement of physically handicapped person, rehabilitation, sports, and so on.

S1502-1-2 シンプルな非線形最適制御を利用して二足歩行から始める実践ロボット教育カリキュラム(工学基礎としてのメカトロ導入教育,社会変革を技術で廻す機械工学)

There is no robot around us in our society at the current stage if we define a robot as an autonomous machine working in the arena of offices, homes, and disaster sites, etc. outside the factories. Mechatronics, dynamics and robotics involving humans are the world of strong nonlinearity. The realized movements of humanoid biped robot using simple nonlinear optimal control use only small active power with simple chaotic limit cycles and showed robustness during walking, running everywhere even on the ice and snow. This paper showed the application of the simple nonlinear optimal control to various movements making full use of instability as a source of driving force and developed into practical education curriculum as an introduction with humanoid biped robot to Robotics having an intellectual and emotional appeal.

A-26 障害予防とパワーアップのためのロバストな「ナンバ・テニス」の提唱 : 平衡点不安定を利用する地面を蹴らない動きの生成(テニス・バドミントン2)

We realized the simple self-sustained humanlike robust walking & running NANBA of humanoid biped robot GENBE based on distributed control of physical body in a martial art, which uses only small active power with simple chaotic limit cycle utilizing instability. Instability makes the natural movement and can be applied to walking of a physically handicapped person, rehabilitation, sports, and so on. This paper showed the development of robust NANBA walking of humanoid Biped Robot GENBE to NANBA-Tennis making full use of instability as a source of driving force.

1G2-3 人間型二足ロボット「源兵衛」による身体に負担の少ない歩行・走行・起き上がり(医療福祉ロボットI,一般講演)

In the previous paper, we realized the simple self-sustained humanlike robust walking & running NANBA of humanoid biped robot GENBE based on distributed control of physical body in a martial art utilizing instability without ZMP (Zero Moment Point) control, which uses only small active power with simple chaotic limit cycle utilizing instability, further developing into autonomous walking, runnung, instantaneous turn and the simple autonomous shock avoidance during falling down and instantaneous rising up. Instability makes the natural movement. This paper introduced experimentally the robustness of humanoid biped robot GENBE who walks and runs everywhere even on the ice and snow, developing to the rising up with light load.

A33 人間型二足ロボット「源兵衛」の「ナンバ歩き・ナンバ走り」のロバスト性のメカニズム(ロボット・スキル)

In the previous paper, we realized the simple self-sustained humanlike robust walking & running NANBA of humanoid biped robot GENBE based on distributed control of physical body in a martial art utilizing instability without ZMP (Zero Moment Point) control, which uses only small active power with simple chaotic limit cycle utilizing instability, further developing into autonomous walking, running, instantaneous turn and the simple autonomous shock avoidance during falling down and instantaneous rising up. Instability makes the natural movement. This paper made clear experimentally by using high-speed video camera the mechanism of robustness of humanoid biped robot GENBE who walks and runs everywhere even on the ice and snow.

Contribution to the calculation of electromagnetic channels for molten metal transportation

The paper presents the construction of a conveying channel of relatively small active power and with direct network supply of the inductor winding. By calculation of the magnetic field with the variables-separation method, on one side, and by representation of the conveying channel as a cascade of four-terminal networks on the other, an equivalent circuit is determined, which takes into consideration the following: the reaction of currents induced in the molten metal, in the protective plate and in the cooling tubes of the inductor, the transverse edge effects, the magnetic field decrease normally to the inductor surface, the influence of slot openings and the higher waves of the travelling magnetic field. Finally two industrial dosing channels are presented.

560 二足ロボット源兵衛のAnti-ZMPによる瞬間的方向転換「ナンバ・ターン」の発現

It seems that the emergence of intelligence in an autonomous robot exists in the dexterity of human or creatures as complex systems and the research style and the development procedure along this approach should be necessary for realization of a real intelligent robot. This paper realized the simple self-sustained humanlike robust instantaneous NANBA TURN about body axis of humanoid biped robot GENBE based on distributed control of physical body in a martial art utilizing instability with Anti-ZMP, which uses only small active power with simple chaotic limit cycle using gravity.

315 自然・生き物・人の巧みさに学ぶ「ヒューマン・ロボット学」の提唱(G15-3 生物モデルロボット,G15 ロボティクス・メカトロニクス)

There is no robot around us in our society at the current stage and also there will be no robot in the future if we define a robot as an autonomous machine working in the arena of offices, homes, and disaster sites, etc. outside the factories and continue the present conventional research and development (R & D) style in robot projects. It seems that the emergence of intellectuality in an autonomous robot exists in the dexterity of human or creatures as complex systems. This paper proposed the research style and the development procedure along this approach for realization of a real intelligent robot. We call this Human-Robotics, where robots and engineers should learn and develop in collaboration with each other in the real world on the basis of the dexterity of nature, life and human. We realized the simple self-sustained humanlike robust walking & running NANBA of humanoid biped robot GENBE based on distributed control of physical body in a martial art utilizing instability without ZMP (Zero Moment Point) control, which uses only small active power with simple chaotic limit cycle utilizing instability, further developing into autonomous walking & running. Instability makes the natural movement. We also investigated the approach to the emergence of the intelligence of an autonomous robot for breaking through the problems of the conventional intelligent robot with SMPA (Sense-Model- Plan- Act) framework in the real world. It is based on the development of human's dexterity or proficient skills with Subsumption Architecture (SA) by learning in the real world.

3E2-03 不安定を利用する人間型二足ロボット「源兵衛」に学ぶ関節に負担の少ない身体操法(OS 立位歩行の安定性と評価)

There is no robot around us in our society at the current stage and also there will be no robot in the future if we define a robot as an autonomous machine working in the arena of offices, homes, and disaster sites, etc. outside the factories and continue the present conventional research and development (R & D) style in robot projects. It seems that the emergence of intellectuality in an autonomous robot exists in the dexterity of human or creatures as complex systems. This paper proposed the approach for realization of a real intelligent robot. We call this Human-Robotics, where robots and engineers should learn and develop in collaboration with each other in the real world on the basis of the dexterity of nature, life and human. We realized the simple self-sustained humanlike robust walking & running NANBA of humanoid biped robot GENBE based on distributed control of physical body in a martial art, which uses only small active power with simple chaotic limit cycle utilizing instability. Instability makes the natural movement and can be applied to walking of a physically handicapped person, rehabilitation, sports, and so on.

3E2-02 自律型二足ロボット「源兵衛」に学ぶ俊敏な転倒時・衝撃回避受け身と起き上がり(OS 立位歩行の安定性と評価)

It seems that the emergence of intelligence in an autonomous robot exists in the dexterity of human or creatures as complex systems and the research style and the development procedure along this approach should be necessary for realization of a real intelligent robot. We proposed in the previous paper the concept of Human-Robotics, where robots and engineers should learn and develop in collaboration with each other in the real world on the basis of the dexterity of nature, life and human. We showed in this paper as the case studies the humanlike robust NANBA walking & running & instantaneous turn of humanoid biped robot GENBE based on distributed control of physical body in a martial art, which uses only small active power with simple chaotic limit cycle utilizing instability. Furthermore, the simple autonomous shock avoidance during falling down and instantaneous rising of biped robot GENBE based on distributed control of physical body in a martial art utilizing instability was shown.

316 「ヒューマン・ロボット学」事例研究 : 移動ロボットと二足歩行ロボットの包摂構造化(G15-3 生物モデルロボット,G15 ロボティクス・メカトロニクス)

We proposed in the previous paper the concept of Human-Robotics, where robots and engineers should learn and develop in collaboration with each other in the real world on the basis of the dexterity of nature, life and human. We showed in this paper as the case studies the simple self-sustained humanlike robust walking & running NANBA of humanoid biped robot GENBE based on distributed control of physical body in a martial art utilizing instability without ZMP (Zero Moment Point) control, which uses only small active power with simple chaotic limit cycle utilizing instability, further developing into autonomous walking & running. Instability makes the natural movement. We also showed the case study of an autonomous robot without SMPA (Sense- Model- Plan- Act) framework. It is based on the development of human's dexterity or proficient skills with Subsumption Architecture (SA) by learning in the real world.

Efficient Bipedal Robots Based on Passive-Dynamic Walkers

Passive-dynamic walkers are simple mechanical devices, composed of solid parts connected by joints, that walk stably down a slope. They have no motors or controllers, yet can have remarkably humanlike motions. This suggests that these machines are useful models of human locomotion; however, they cannot walk on level ground. Here we present three robots based on passive-dynamics, with small active power sources substituted for gravity, which can walk on level ground. These robots use less control and less energy than other powered robots, yet walk more naturally, further suggesting the importance of passive-dynamics in human locomotion.

Experimental study on system stability evaluation in parallel running of a superconducting generator and a SMES

Parallel running operation of 100 kVA superconducting generator (SCG) with high response excitation and 0.4 MJ SMES (superconducting magnet energy storage) was carried out. The exciter capacity of the high response excitation is rather large compared with that of conventional generators. The exciter controller, that is, AVR (automatic voltage regulator) and PSS (power system stabilizer) are designed taking the exciter power change at the excitation into account to improve the system stability. The SMES can also improve the power system stability. The SMES can give the small active power modulation of sinusoidal wave to the system. The system responses due to the SMES power modulation were observed and analyzed in order to evaluate the designed control functions of AVR, PSS and SMES. Frequency characteristics of the designed control functions were obtained from on-line data of the system. The system stability of parallel running of the SCG and the SMES was evaluated by use of SMES power control.