Yasuaki Kuroe

Analysis of bifurcation in power electronic induction motor drive systems

Instability phenomena in power electronic induction motor drive systems are investigated from the point of view of bifurcation theory. A method to determine bifurcation values of system parameters is discussed. It is shown that some kinds of bifurcations are observed in power electronic induction motor drive systems. The proposed method makes it possible not only to determine instability regions of system parameters, but also to investigate qualitative properties of the instability phenomena.<<ETX>>

Computation of sensitivities with respect to conduction time of power semiconductors and quick determination of steady state for closed-loop power electronic systems

Two problems related to computer-aided analysis of power electronic systems are dealt with. Firstly, an efficient algorithm is proposed for computing sensitivities of system behavior with respect to conduction time of power semiconductors for general power electronic systems. The adjoint network approach based on Tellegens theorem is extended for computing those sensitivities in an accurate and efficient manner. Secondly, a method for quick determination of the steady state of power electronic systems with closed control loops is discussed. An efficient algorithm for computing the steady state is proposed that makes use of the computed sensitivities.<<ETX>>

A general steady-state analysis program ANASP for thyristor circuits based on adjoint-network approach

Described is a new computer aided package program ANASP for computing the steady-state waveforms for any configuration of thyristor circuits. Newton-Raphson method is used to compute the initial state which generates the steady-state waveforms. For the efficient and accurate evaluation of the Jacobi an matrix the adjoint network is introduced into thyristor circuits containing power diodes and thyristors, and the method of sensitivity calculation is proposed. Using the program implemented, it is shown through examples that the computational time is considerably reduced to deter mine the steady state.

A new computer-aided method of distortion sensitivity-analysis and its elimination scheme for power electronic circuits

A new general computer-aided algorithm for computing parameter sensitivities of distortion in power electronic circuits and its elimination scheme are proposed. The adjoint network approach is employed for calculating parameter sensitivities of the distortion factor and the ripple factor of current and voltage waveforms. An optimal filter design-algorithm to reduce undesirable harmonics is also proposed. Their performance is shown to be superior through demonstrated numerical examples.

Computer-aided analysis of power-electronic DC-motor drives: transient and steady-state analysis

Described are new and efficient computer-aided analysis packages for general power-electronic dcmotor drive systems. They compute both transient and steady-state waveforms for arbitrary field excitations and any thyristor configuration automatically. Users are only required to input circuit parameters, thyristor gate timing, machine constants and their connections in a free format.

Computer aided method to analyze parameter sensitivity of switching time of power semiconductors and its application to optimal design for power electronic circuits

In recent years there has been paid much attention to the development of computer aided methods in analysis and design of power electronic circuits because the recent advances of switching power semiconductor devices. In this paper we propose a new and efficient computer aided algorithm for computing parameter sensitivities of turn-on and turn-off instants of power semiconductors for any given power electronic circuits. It is shown that sensitivities of switching instants of power electronic circuits are expressed in terms of parameter sensitivities of voltage and current values by using implicit function theorem. The adjoint network approach based on Tellegens theorem is employed for calculating those sensitivities. The optimal circuit design method by making use of the sensitivity calculation is also developed. Their superior performance is demonstrated through some examples by using the implemented computer packages.

A new computer-aided method of distortion sensitivity-analysis and is elimination scheme for power electronic circuits

Proposed are a new general computer-aided algorithm for computing parameter sensitivities of distortion in power electronic circuits and its elimination scheme. The adjoint network approach is employed for calculating parameter sensitivities of the distortion factor and the ripple factor of current and voltage waveforms. The optimal filter design-algorithm to reduce undesirable harmonics is also proposed. Their performance is shown to be superior through demonstrated numerical examples.