Simulative Analysis of Power Conversion System for Hybrid Electric Vehicles Based on Dual Input Sources Including Charging From Solar Panel

Renewable energy sources are highly recommended in hybrid electric vehicles (HEV) applications. The power converters play an important role in hybrid electric vehicle system. The design of control system for such converters is discussed in the paper. The design of both DC-DC dual input converter and 3 phase VSC is done using MATLAB simulation. The design of SVPWM technique is presented for three phase VSC and PI control is for DC-DC converter. By the integration of this system a 3 phase induction motor will be operated, which in turn can be utilized for running of shaft of any vehicle. The dual input converter feed by two sources one is PV system and other is battery which is being charged by the PV system.

How Problem-Solving Tasks Work in a Mathematics Classroom in Relation to Developing Students Mathematical Thinking

The efforts to improve the teaching and learning of mathematics involve varied approaches; the problem-solving approach is one of them. This research study sets out to understand how problem-solving tasks work in a mathematics classroom in relation to developing students' mathematical thinking. The objective was to teach mathematics in a lower-secondary class using problem-solving tasks and to find out how it works in a natural setting, i.e. classroom environment. A qualitative research paradigm was used, the action research in particular, because the study intended to implement the problem-solving approach in teaching mathematics and to find out its impact on the students' mathematical thinking. The findings of this research study show that problem-solving tasks can work in a mathematics classroom in relation to developing the students' mathematical thinking, and that there are processes involved in this regard which include: finding out and using what the students' already know, planning for the problem solving tasks, preparing the conducive classroom environment, and implementing problem solving tasks in a mathematics classroom. The related supporting factors include: the teaching approach, the teacher's role, students' understanding of why learn mathematics, and addressing the students' learning problems as they emerge. However, there are issues that need to be addressed in order to facilitate this kind of classroom practice. The main hindering factors found out include: the right answers myth, the time factor, and the use of the English language. The study concludes by highlighting the lesson learnt as a result of conducting this research study as a teacher-researcher, a mathematics teacher educator and as an agent of change. It provides my overall learning of researching in school, the research implications, and it recommends areas for further research and offers questions for reflection as a guide for needs analysis in the respective contexts to mathematics teachers, mathematics teacher educators, decision makers, and the related educational stake holders. It is expected that the answers to the needs analysis reflective questions would identify specific intentions' for a particular context.