Sensorless control for limp-home mode of EV applications

PhD ThesisOver the past decade research into electric vehicles’ (EVs) safety, reliability and availability has become a hot topic and has attracted a lot of attention in the literature. Inevitably these key areas require further study and improvement. One of the challenges EVs face is speed/position sensor failure due to vibration and harsh environments. Wires connecting the sensor to the motor controller have a high likelihood of breakage. Loss of signals from the speed/position sensor will bring the EV to halt mode. Speed sensor failure at a busy roundabout or on a high speed motorway can have serious consequences and put the lives of drivers and passengers in great danger. This thesis aims to tackle the aforementioned issues by proposing several novel sensorless schemes based on Model Reference Adaptive Systems (MRAS) suitable for limp-home mode of EV applications. The estimated speed from these schemes is used for the rotor flux position estimation. The estimated rotor flux position is employed for sensorless torque-controlled drive (TCD) based on indirect rotor field oriented control (IRFOC). The capabilities of the proposed schemes have been evaluated and compared to the conventional back-Electromotive Force MRAS (back-EMF MRAS) scheme using simulation environment and a test bench setup. The new schemes have also been tested on electric golf buggies. The results presented for the proposed schemes show that utilising these schemes provide a reliable and smooth sensorless operation during vehicle test-drive starting from standstill and over a wide range of speeds, including the field weakening region. Employing these new schemes for sensorless TCD in limp-home mode of EV applications increases safety, reliability and availability of EVs

Design and psychometric measurement of the questionnaire on attitude, knowledge and utilization of self-care for patients undergoing coronary artery bypass graft surgery based on Waltz model

Background. Self-care behaviors in cardiac patients are one of the essential factors in their treatments. The failure to apply proper self-care behaviors reduces their recovery and imposes high costs on the health care system. Aim. This study aimed for design and psychometric measurement of the questionnaire on attitude, knowledge and utilization of self-care for patients undergoing coronary artery bypass graft surgery based on Waltz model Method. In this methodological study, the following four steps were conducted for design and psychometric measurement of the questionnaire: 1) defining the theoretical and practical self-care concept for patients undergoing coronary artery bypass graft surgery in the domains of physical activity, sexual activity, social activity, mental state, and smoking; 2) designing the items of the questionnaire using other instruments which are being used in heart diseases; 3) determining the face validity (the assessment of facility, difficulty, and ambiguity of the items and their importance for patients) and content validity of the questionnaire (the assessment of appropriateness and necessity of items by experts opinions and measuring CVR and CVI; 4) the internal consistency of the questionnaire was evaluated by determining the Cranach's alpha coefficient. Findings. The first version of this questionnaire was produced with 56 items, of which 15 items were deleted during the process of validity and reliability confirmation. The final version of the questionnaire was provided with 41 items in three domains; knowledge domain with 14 items, attitude domain with 7 items and utilization domain with 20 items. The results of the psychometric procedure for the questionnaire was the content validity index of 0.99, the content validity ratio of 0.96 and the internal consistency of the questionnaire with Cronbach's alpha coefficient of 0.7 representing appropriate validity and reliability of the questionnaire. Conclusion. This 41-item questionnaire can be utilized in the assessment process of these patients. Measuring construct validity is recommended for the validity of the domains of the present questionnaire

Sensorless Control of im for Limp-Home Mode EV Applications

This paper presents a novel speed estimation scheme for induction motors (IMs) based on back electromotive-force model reference adaptive system (back-EMF MRAS). The scheme is employed for the purpose of sensorless fault-Tolerant torque-controlled drives used in a limp-home mode operation in electric vehicle (EV) applications. The proposed scheme was experimentally tested on a laboratory dynamometer using a 19-kW IM and a 29-kW controller, which are both currently used in the automotive industry for EV applications. The scheme was also implemented on an electric golf buggy which was equipped with a 5-kW IM. A performance comparison was carried out between the proposed and conventional back-EMF MRAS schemes for starting from standstill, sensitivity to parameter variations and constant speed operation with load variations. Utilizing the golf buggy, the behaviors of the new scheme was separately investigated for vehicle starting from standstill, wide speed range including field weakening region, and hill-starting operations. The proposed scheme is computationally easy to implement, robust against sensitivity to parameters variations, inverter nonlinearity and errors due to digitization in the field weakening region. This scheme is not only consistent for vehicle starting from standstill, it also provides a reliable vehicle-drive in the field weakening region and during vehicle hill-starting. The dynamometer and vehicle test-drive results show the suitability of the proposed scheme for the purpose of EV fault-Tolerant limp-home mode operation

Exploring the impact of gender inequities on the promotion of cardiovascular health of women in Pakistan

Cardiovascular disease exerts an enormous burden on women\u27s health. The intake of a healthy diet may reduce this burden. However, social norms and economic constraints are often factors that restrain women from paying attention to their diet. Underpinned by critical realism, this study explores how gender/sex influences decision-making regarding food consumption among women of low socioeconomic status (SES). The study was carried out at two cardiac facilities in Karachi, Pakistan, on 24 participants (male and female from different ethnic backgrounds), who had received health education. Using an interpretive descriptive approach, the study identified major barriers to a healthy diet: proscribed gender roles and lack of women\u27s autonomy, power, male domination, and abusive behaviours. Cardiovascular risk and disease outcomes for the Pakistani women of low SES are likely to further escalate if individual and structural barriers are not reduced using multifactorial approaches

Co-designing new tools for collecting, analysing and presenting patient experience data in NHS services: working in partnership with patients and carers

Background The way we collect and use patient experience data is vital to optimise the quality and safety of health services. Yet, some patients and carers do not give feedback because of the limited ways data is collected, analysed and presented. In this study, we worked together with researchers, staff, patient and carer participants, and patient and public involvement and engagement (PPIE) contributors, to co-design new tools for the collection and use of patient experience data in multiple health settings. This paper outlines how the range of PPIE and research activities enabled the co-design of new tools to collect patient experience data. Methods Eight public contributors represented a range of relevant patient and carer experiences in specialist services with varied levels of PPIE experience, and eleven members of Patient and Participation Groups (PPGs) from two general practices formed our PPIE group at the start of the study. Slide sets were used to trigger co-design discussions with staff, patient and carer research participants, and PPIE contributors. Feedback from PPIE contributors alongside verbatim quotes from staff, patient and carer research participants is presented in relation to the themes from the research data. Results PPIE insights from four themes: capturing experience data; adopting digital or non-digital tools; ensuring privacy and confidentiality; and co-design of a suite of new tools with guidance, informed joint decisions on the shaping of the tools and how these were implemented. Our PPIE contributors took different roles during co-design and testing of the new tools, which supported co-production of the study. Conclusions Our experiences of developing multiple components of PPIE work for this complex study demonstrates the importance of tailoring PPIE to suit different settings, and to maximise individual strengths and capacity. Our study shows the value of bringing diverse experiences together, putting patients and carers at the heart of improving NHS services, and a shared approach to managing involvement in co-design, with the effects shown through the research process, outcomes and the partnership. We reflect on how we worked together to create a supportive environment when unforeseen challenges emerged (such as, sudden bereavement)

Co-designing new tools for collecting, analysing and presenting patient experience data in NHS services: working in partnership with patients and carers

From Springer Nature via Jisc Publications RouterHistory: received 2021-07-12, accepted 2021-11-15, registration 2021-11-17, pub-electronic 2021-11-27, online 2021-11-27, collection 2021-12Publication status: PublishedFunder: health services and delivery research programme; doi: http://dx.doi.org/10.13039/501100002001; Grant(s): 14/156/16Abstract: Background: The way we collect and use patient experience data is vital to optimise the quality and safety of health services. Yet, some patients and carers do not give feedback because of the limited ways data is collected, analysed and presented. In this study, we worked together with researchers, staff, patient and carer participants, and patient and public involvement and engagement (PPIE) contributors, to co-design new tools for the collection and use of patient experience data in multiple health settings. This paper outlines how the range of PPIE and research activities enabled the co-design of new tools to collect patient experience data. Methods: Eight public contributors represented a range of relevant patient and carer experiences in specialist services with varied levels of PPIE experience, and eleven members of Patient and Participation Groups (PPGs) from two general practices formed our PPIE group at the start of the study. Slide sets were used to trigger co-design discussions with staff, patient and carer research participants, and PPIE contributors. Feedback from PPIE contributors alongside verbatim quotes from staff, patient and carer research participants is presented in relation to the themes from the research data. Results: PPIE insights from four themes: capturing experience data; adopting digital or non-digital tools; ensuring privacy and confidentiality; and co-design of a suite of new tools with guidance, informed joint decisions on the shaping of the tools and how these were implemented. Our PPIE contributors took different roles during co-design and testing of the new tools, which supported co-production of the study. Conclusions: Our experiences of developing multiple components of PPIE work for this complex study demonstrates the importance of tailoring PPIE to suit different settings, and to maximise individual strengths and capacity. Our study shows the value of bringing diverse experiences together, putting patients and carers at the heart of improving NHS services, and a shared approach to managing involvement in co-design, with the effects shown through the research process, outcomes and the partnership. We reflect on how we worked together to create a supportive environment when unforeseen challenges emerged (such as, sudden bereavement)