Hiroki Goto, Ayumu Nishimiya, Hai‐Jiao Guo and Osamu Ichinokura
The purpose of this paper is to propose a new instantaneous torque control method for switched reluctance motor (SR motor) and presents experimental data in electric vehicle (EV…
Abstract
Purpose
The purpose of this paper is to propose a new instantaneous torque control method for switched reluctance motor (SR motor) and presents experimental data in electric vehicle (EV) application.
Design/methodology/approach
The proposed control method uses two kind of techniques: a flux‐based commutation technique prevents the negative phase torque always. On the other hand, a direct phase‐torque distribution technique gives suitable each phase‐torque command under limited DC voltage. These techniques can track motor torque to the command. These control schemes are implemented on a small processor and a field programmable gate array.
Findings
The experimental results of the EV show small torque ripple at low speed on both acceleration and regenerative braking. Changing the parameter of the current stop angle can improve torque ripple at high speed. The proposed method can effectively control motor torque.
Practical implications
The proposed method can reduce torque ripple but the implementation is very simple. The proposed control method can be used for any applications. So, that contributes to expand the application of SR motors.
Originality/value
The proposed control scheme requires just static torque curve obtain by finite element analysis or simple experiments. Complex parameters, such as nonlinear inductance, current to torque profiles, and other heuristics parameters, are not necessary. The proposed control is simple but practical.
Details
Keywords
Ryuichi Nakamoto, Hao-Cheng Chen, Hiroki Noguchi and Shohei Funatsu
The Penrose effect, or the limitation of the growth rate during expansion due to managerial constraints, has been examined in the context of business diversification, withdrawal…
Abstract
Purpose
The Penrose effect, or the limitation of the growth rate during expansion due to managerial constraints, has been examined in the context of business diversification, withdrawal and MNE’s foreign direct investment, primarily in the for-profit sector. However, insufficient attention has been paid to its impact on professional service firms, particularly in the context of their expansion through service exports. The main purpose of this study is to examine the Penrose effect in the internationalization of professional service firms through service exports.
Design/methodology/approach
This study focuses on large Japanese patent firms as traditional professional service firms and constructs panel data for 48 large patent firms over the observation period from 2002 to 2010 to test our hypotheses.
Findings
Our results demonstrate a negative relationship between degree of internationalization and international business growth, thus confirming the Penrose effect. Furthermore, we found that the degree of internationalization has a curvilinear relationship with international business growth and that institutional distance does not have a negatively moderating effect on the relationship between the degree of internationalization and international business growth.
Originality/value
This study made a theoretical contribution to Penrose's growth theory and previous studies on international management and professional service firms and international management by showing that the Penrose effect can be observed in the international expansion of professional service firms through service exports. Moreover, this study identifies the factors that modify the Penrose effect, thereby making a significant theoretical contribution.
Details
Keywords
Japan is home to a relatively conservative and group-oriented culture in which social expectations can exert powerful pressure to conform to traditional patterns of behaviour…
Abstract
Japan is home to a relatively conservative and group-oriented culture in which social expectations can exert powerful pressure to conform to traditional patterns of behaviour. This includes gender norms, which have long been based around the common stereotypes of men as breadwinners and women as housewives. Social liberalisation and economic change in the late 20th century saw these patterns change as more women entered the workforce and, despite Japan's dismal standing in global equality rankings, began to make inroads into some positions of political and corporate leadership. Yet, the way in which women are treated by men is shaped not only by female gender norms but also by the social factors that determine male patterns of behaviour. This chapter considers how Japan's male gender norms, particularly the focus on man as economic labourers rather than active members of the family unit, have damaged many men's ability to connect, on an emotional level, with the women in their lives. It looks at the issue of misogyny; what is known as the Lolita Complex; the growing trend of herbivore men; and the concept of Ikumen, men who are active within the family. While some of these patterns of behaviour can be harmful – for women on the individual level, and for Japan as a whole, on the social level – there are some trends which suggest that gender norms in Japan can be directed in a manner which will allow for much healthier emotional relationships to develop between the genders in a manner that will help build a society that is more cognisant of and attentive to the needs of women.