In the electrified society for decarbonization, it is important to solve conflicting technical issues such as increasing the cruising range and shortening the charging time as EVs spread. In order to extend the cruising range, it is necessary to mount a large-capacity battery and the smaller and lighter equipment, it is also necessary to have a large amount of infrastructure for rapid charging. This paper describes the progress of higher performance of devices and the direction of EV drive systems in the future.

Solving complex symmetric systems efficiently is a significantly important issue in the applications of electromagnetics since the discretization of the numerical model using the finite element method results in complex symmetric systems when computing the electromagnetic field. However, such complex symmetric systems are usually much more difficult to be solved because of the property of non-Hermitian therefore, efficient numerical methods for the solution of complex symmetric systems are demanded. In this study, we proposed an iterative method called COMINRES-QLP which is specially designed for complex symmetric linear systems. Moreover, we proposed a new stopping criterion which could be very useful in practical computations when the condition number of the coefficient matrix is unknown.

Recently, a lot of photovoltaic (PV) generation systems have been penetrated in distribution power systems. It is important for the power system operators to know a total value of PV output and real load of a distribution line in real time. But the real load is unmeasurable while the PV systems are generating. This paper describes an estimation method of PV output and a forecasting method of real load in a distribution line using two types of Kalman filters with power flow data (P, Q) and solar radiation. These methods were examined for accuracy in a real distribution line in Hokuriku Electric Power Company. The root mean square errors (RMSEs) for estimated PV output and 2-hour forecasted real load were about 7% and 10% error rate of total PV capacity through one year, respectively. These results show that these methods would be acceptable for power system operators because this method is simpler than the other methods that have been proposed in the past.

Using the current injection method, how to calculate the transient recovery voltages in three-phase asymmetrical current interruption in analysis has been devised. This calculation is applicable to both effectively earthed neutral system and non-effectively earthed neutral system. Since the transient recovery voltages of three-phase test duty T100a are calculated, the performance of the circuit breaker in three-phase asymmetrical current interruption can be estimated more correctly in synthetic testing.

Deep learning is applied to IPM motors with different magnet shapes to realize fast topology optimization. In this method, the cross-sectional image of IPM motors with I-shaped and V-shaped magnets are input to a convolutional neural network to guess their average torque. It is shown that simultaneous learning, in which CNN is trained for both datasets, is superior over the additional learning where CNN is sequentially trained for the two datasets. Moreover, it is shown that the number of required finite element analysis can be reduced to about five percent using the trained CNN in the topology optimization.

The Editorial Committee is working in planning and editing of the publication of Power and Energy Society. In this article, activities of the committee of the last term are reported, and recent trend and future problems are also discussed. The process of planning and editing of the publication, and the challenges to reduce the necessary months for reviewing papers and to increase the number of submitted papers are shown.