Yuzo Itoh

The design of control configuration of variable speed generator system

In this paper a new designing method for a variable rotating speed generator system (VSGS) is presented. The rotor speed of the traditional synchronous generator system is exactly regulated to the power system frequency by the manner of mechanical governor control, VSGS has no necessity of frequency control by a mechanical control system. The machine employed in VSGS is a wound type induction machine. VSGS is applied to the pumped storage generator system which elevates a running efficiency. And the system with large rotating inertia is used to improve the stability for the step load variation in the power system. As the other utilization, it can be applied to wind turbine systems and asynchronous rotary machines which can provide not only electrical reactive power but active power. So, a variable speed generator will be used as the device of flexible AC transmission system (FACTS). For those application of VSGS, the stable and quick response for the system references and step change of power output are required. In order to obtain the steady and transient state behavior of VSGS, the instantaneous vector analysis is employed. To design a control system for VSGS, a developed optimal control theory is applied. The system response of VSGS designed by the proposed method is simulated and is experimented on in the case of constant generating mode while the shaft input is increasing. Finally, the effectiveness of the proposed control method for a variable speed generator system is confirmed.

The advanced speed regulator system for brushless motor

A new design method for the optimum speed regulator system for a permanent-magnet-type brushless motor is proposed. The driving method developed through examining the armature reaction consists of vector control, field weakening, and field strengthening, control. Since the PM motor has the property of nonlinearity, it is necessary to linearize the motor system at the arbitrary equilibrium point when the optimal feedback gains of the state feedback control are determined in the usual system design method. Therefore, a quick transient response can be obtained only near the equilibrium point. By introducing the dynamic compensation signal in order to linearize the controlled object, the decoupled subsystem can be constructed. Hence, the d-axis current and the q-axis current can be controlled independently. In order to obtain the quick speed response, a microprocessor-based controller including a digital signal processor (DSP) is used in the implementation of this control system.<<ETX>>