Toshihisa Funabashi

A unit commitment problem by using genetic algorithm based on unit characteristic classification

This paper presents new approach for thermal unit commitment problem. Unit commitment (UC) problem plays a major role in power systems since the improvement of commitment schedules results in the reduction of operating cost. However, the unit commitment problem is one of the most difficult optimization problems in power system, because they have many constraints. Further, these constraints vary with each unit. To handle these constraints, some cording methods have been proposed. However, these methods require computation time. To overcome these problems, a new genetic operator based on unit characteristic classification and intelligent techniques generating initial populations are introduced. The proposed algorithm was tested on a reported UC problem. From simulation results, satisfactory solutions are obtained in comparison with previously reported results. Numerical results for system of up to 100 units are compared to previously reported results.

Output Power Control for Large Wind Power Penetration in Small Power System

Nowadays, wind turbine generator (WTG) is increasingly required to provide control capabilities regarding output power. Under this scenario, this paper proposes an output power control of WTG using pitch angle control connected to small power systems. By means of the proposed method, output power control of WTG considering states of power system becomes possible, and in general both conflicting objectives of output power leveling and acquisition power increase are achieved. In this control approach, WTG is given output power command by fuzzy reasoning which has three inputs for average wind speed, variance of wind speed, and absolute average of frequency deviation. Since fuzzy reasoning is used, it is possible to define output power command corresponding to wind speed condition and changing capacity of power system momentarily. Moreover, high performance pitch angle control based on output power command is achieved by generalized predictive control (GPC). The simulation results by using actual detailed model for wind power system show the effectiveness of the proposed method.

Oscillation frequency control based on H/sub /spl infin// controller for a small power system using renewable energy facilities in isolated island

Output power from wind turbine generators occurs a large frequency fluctuation on small power systems. In order to solve this problem, we propose an oscillation frequency control for a new power supply system with using renewable energy facilities in isolated island. The proposed system can supply a high-quality power using aqua electrolyzers, fuel cells, renewable energy, and diesel generators. The feature of proposed system is to use an aqua electrolyzers and fuel cells. The hydrogen generated by the aqua electrolyzers is used as fuel of fuel cells. The simulation results and the efficiency of proposed system are shown in this paper

Robust Predictive Control of Variable-Speed Wind Turbine Generator by Self-Tuning Regulator

The parameter variation problem in controller design for wind turbine generator (WTG) systems due to wind speed fluctuations is addressed in this paper. The wind speed is generated by an auto-regressive and moving average (ARMA) model while drive-train components are modelled as a two- mass system described by non-linear equations for accurate dynamic performance assessment. The control of the unit is exercised through a multi-input, multi-output (MIMO) self- tuning regulator (STR) that uses the local generator speed to produce appropriate control signals for compensating parametric uncertainty. The parameters of the STR are adjusted online for quality improvement of the power supply under turbulent wind. Simulation results show the proposed controller causes the closed- loop wind turbine to behave as a simple first order power filter, where power output is a low-pass filtered version of the incident wind power. Further, the control scheme achieves the regulation of torsional dynamics without involving converter controls.

On-line dead-time compensation method for voltage source inverter fed motor drives

This paper presents an on-line dead-time compensation method for inverter fed motor drives. The amplitude of the dead time compensation voltage (DTCV) is estimated on-line from the disturbance voltage due to nonideal inverter affects. The experimental results indicate that the adaptive DTCV reduces error between the calculated and actual power.