This thesis develops dynamic models for the two-mode FWD EVT, develops a control system based on those models that is capable of meeting driver torque demands and performing synchronous mode shifts between different EVT modes while also accommodating preferred engine operating points. The two-input two-output transmission controller proposed herein incorporates motor-generator dynamics, is based on a general state-space integral control structure, and has feedback gains determined using linear quadratic regulator (LQR) optimization. Dynamic modeling of the vehicle is categorized as dynamic modeling of the mechanical and electrical subsystems where the mechanical subsystem consists of the planetary gear sets, the transmission and the engine whereas the electrical subsystem consists of the motor-generator units and the battery pack. A discussion of load torque is also considered as part of the mechanical subsystem. With the help of these derived dynamic models, a distinction is made between dynamic output torque and steady-state output torque. The overall control system consisting of multiple subsystems such as the human driver, power management unit (PMU), friction brakes, combustion engine, transmission control unit (TCU) and motor-generator units is designed. The logic for synchronous mode shifts between different EVT modes is also detailed as part of the control system design. Finally, the thesis presents results for responses in individual operating modes, EVT mode shifting and a full UDDS drive cycle simulation.

The main goal of this thesis is to develop practical digital controller architectures for multi-phase dc-dc converters utilized in low power (up to few hundred watts) and cost-sensitive applications. The proposed controllers are suitable for on-chip integration while being capable of providing advanced features, such as dynamic efficiency optimization, inductor current estimation, converter component identification, as well as combined dynamic current sharing and fast transient response. The first part of this thesis addresses challenges related to the practical implementation of digital controllers for low-power multi-phase dc-dc converters. As a possible solution, a multi-use high-frequency digital PWM controller IC that can regulate up to four switching converters (either interleaved or standalone) is presented. Due to its configurability, low current consumption (90.25 μA/MHz per phase), fault-tolerant work, and ability to operate at high switching frequencies (programmable, up to 10 MHz), the IC is suitable to control various dc-dc converters. The applications range from dc-dc converters used in miniature battery-powered electronic devices consuming a fraction of watt to multi-phase dedicated supplies for communication systems, consuming hundreds of watts. A controller for multi-phase converters with unequal current sharing is introduced and an efficiency optimization method based on logarithmic current sharing is proposed in the second part. By forcing converters to operate at their peak efficiencies and dynamically adjusting the number of active converter phases based on the output load current, a significant improvement in efficiency over the full range of operation is obtained (up to 25%). The stability and inductor current transition problems related to this mode of operation are also resolved. At last, two reconfigurable digital controller architectures with multi-parameter estimation are introduced. Both controllers eliminate the need for external analog current/temperature sensing circuits by accurately estimating phase inductor currents and identifying critical phase parameters such as equivalent resistances, inductances and output capacitance. A sensorless non-linear, average current-mode controller is introduced to provide fast transient response (under 5 μs), small voltage deviation and dynamic current sharing with multi-phase converters. To equalize the thermal stress of phase components, a conduction loss-based current sharing scheme is proposed and implemented.

La présence importante de plusieurs réseaux sans-fils de différentes portées a encouragée le développement d’une nouvelle génération d’équipements portables sans-fils avec plusieurs interfaces radio. Ainsi, les utilisateurs peuvent bénéficier d’une large possibilité de connectivité aux réseaux sans-fils (e.g. Wi-Fi [1], WiMAX [2], 3G [3]) disponibles autour. Cependant, la batterie d’un nœud mobile à plusieurs interfaces sera rapidement épuisée et le temps d’utilisation de l’équipement sera réduit aussi. Pour prolonger l’utilisation du mobile les standards, des réseaux sans-fils, on définie (individuellement) plusieurs états (émission, réception, sleep, idle, etc.); quand une interface radio n’est pas en mode émission/réception il est en mode sleep/idle où la consommation est très faible, comparée aux modes émission/réception. Pourtant, en cas d’équipement portable à multi-interfaces radio, l’énergie totale consommée par les interfaces en mode idle est très importante. Autrement, un équipement portable équipé de plusieurs interfaces radio augmente sa capacité de connectivité mais réduit sa longévité d’utilisation. Pour surpasser cet inconvénient on propose une plate-forme, qu'on appelle IMIP (Integrated Management of Interface Power), basée sur l’extension du standard MIH (Media Independent Handover) IEEE 802.21 [4]. IMIP permet une meilleure gestion d’énergie des interfaces radio, d’un équipement mobile à multi-radio, lorsque celles-ci entrent en mode idle. Les expérimentations que nous avons exécutées montrent que l’utilisation de IMIP permet d'économiser jusqu'a 80% de l'énergie consommée en comparaison avec les standards existants. En effet, IMIP permet de prolonger la durée d'utilisation d'équipements à plusieurs interfaces grâce à sa gestion efficace de l'énergie. / The large availability of wireless networks of different ranges, has contributed to the development of new generation of handheld devices with multi-radio interfaces. Thus, the end-users are able to achieve ubiquitous and seamless connectivity across heterogeneous wireless networks (e.g., Wi-Fi [1], WiMAX [2] and 3G_LTE [3]). However, a mobile node with multi-radio interfaces has its battery energy consumed rapidly, which reduces the operation/usage time of the device. To improve battery usage, wireless network standards have defined (individually) different interface states (transmit, receive, idle, sleep, etc.); when an interface is not transmitting or receiving, it goes to sleep/idle state where energy consumption is very low compared to transmit and receive states. However, in the case of multi-radio handheld devices, the total energy consumed by the interfaces in sleep/idle state is significant. Thus, equipping a mobile device with multiple interfaces increases its seamless connectivity but reduces its operation/usage longevity. To overcome this inconvenient, we proposed a framework, called IMIP (Integrated Management of Interface Power) that consists of an extension of MIH (Media Independent Handover) IEEE 802.21 standard [4]. IMIP allows a better power management of radio interfaces of a multi-radio mobile node; indeed, it reduces considerably energy consumption. The basic idea behind IMIP is to shut down any interface in idle mode and use a proxy that emulates the interface; the proxy wakes up the interface when it receives a connection request directed to this interface. IMIP requires at least one interface in active mode. Experiments show that using IMIP enables a saving of up to 80% of power consumption compared with existing power management standards. Thus, IMIP allows longer usage of multiple interface devices thanks to its effective energy management.

The main goal of this thesis is to develop practical digital controller architectures for multi-phase dc-dc converters utilized in low power (up to few hundred watts) and cost-sensitive applications. The proposed controllers are suitable for on-chip integration while being capable of providing advanced features, such as dynamic efficiency optimization, inductor current estimation, converter component identification, as well as combined dynamic current sharing and fast transient response. The first part of this thesis addresses challenges related to the practical implementation of digital controllers for low-power multi-phase dc-dc converters. As a possible solution, a multi-use high-frequency digital PWM controller IC that can regulate up to four switching converters (either interleaved or standalone) is presented. Due to its configurability, low current consumption (90.25 μA/MHz per phase), fault-tolerant work, and ability to operate at high switching frequencies (programmable, up to 10 MHz), the IC is suitable to control various dc-dc converters. The applications range from dc-dc converters used in miniature battery-powered electronic devices consuming a fraction of watt to multi-phase dedicated supplies for communication systems, consuming hundreds of watts. A controller for multi-phase converters with unequal current sharing is introduced and an efficiency optimization method based on logarithmic current sharing is proposed in the second part. By forcing converters to operate at their peak efficiencies and dynamically adjusting the number of active converter phases based on the output load current, a significant improvement in efficiency over the full range of operation is obtained (up to 25%). The stability and inductor current transition problems related to this mode of operation are also resolved. At last, two reconfigurable digital controller architectures with multi-parameter estimation are introduced. Both controllers eliminate the need for external analog current/temperature sensing circuits by accurately estimating phase inductor currents and identifying critical phase parameters such as equivalent resistances, inductances and output capacitance. A sensorless non-linear, average current-mode controller is introduced to provide fast transient response (under 5 μs), small voltage deviation and dynamic current sharing with multi-phase converters. To equalize the thermal stress of phase components, a conduction loss-based current sharing scheme is proposed and implemented.

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Summaries in English, Tsonga and Venda / Dyondzo yi lavisisa vutlhari lebyi nga kona eka marungula ya tiprosi ta Xitsonga byo kambisisa swikili swa vulawuri na switirateji swa mbulavurisano leswi tirhisiwaka hi varhangeri va sweswi eka tisosayiti. Mahungu hinkwawo ya mbulavurisano wa swiharhi na vanhu ya nyikiwile lama kongomisaka eka tinxaka ta vurhangeri na swikili. Marungula ya tiprosi ta Xitsonga lama hlawuriweke na ku dokhumentiwa na marungula hi varhangeri va sweswi ya hlengeletiwile naswona ya xopaxopiwile. Dyondzo yi leteriwile hi Nxopanxopo wa Mbulavulo wa Nkoka, Mbulavurisano wa Vanhu, na maendlelo ya vutitivisi bya Vanhu. Datara yi lulamisiwile hi mitlawa ku ya hi mikhetekanyo leyi hlawuriweke ya switirateji swa mbulavurisano wa nomu na wo ka wu nga ri wa nomu. Mavulavulelo ya vanhu lava nga eka swiyimo swa vurhangeri eka marungula ya tiprosi na ya vanhu va sweswi ya hlamuseriwile na ku va ya xopaxopiwile hi ku ya hi maendlelo lama hlawuriweke. Leswi nga kumiwa swi humeserile erivaleni leswaku hakunene, varhangeri va sweswi va kayivela swikili swa vulawuri na switirateji swa mbulavurisano. Milawu ya vurhangeri leyi kambisisiweke leyi languteriweke ku suka eka varhangeri votala va vanhu yi kumiwile yi nga ri kona. Swiyimo swa malawulelo na mafumelo yo biha hi ndlela ya ntirhiso wo ka wu nga ri kahle kumbe nkucetelo swi kombisiwile ku suka eka ku tirhisa switirateji swa mbulavurisano wa nomu na wo ka wu nga ri wa nomu hi ndlela yo ka yi nga ri kahle. Makolo, vukari na ku tshembhela eka swa vukhongeri kumbe swikwembu swa le hansi a ku ri swona a swi vanga malawulelo na mafumelo yo biha. Vatirhivotala va xiyimo xa le hansi va hlanganile na ku xanisiwa emimoyeni, ku xanisiwa hi ku vulavula na ku xanisiwa emirini, ku xanisiwa hi swa masangu na ku susiwa eka swiyimo swa vona ehansi ka vulawuri bya varhangeri va vona eka sosayiti. Varhangeri va sweswi va nga dyondza swotala hi swikili swa vulawuri na switirateji swa mbulavurisano ku suka eka marungula ya tiprosi ta tindzimi ta Afrika, ngopfu-ngopfu marungula ya tiprosi ta Xitsonga. Dyondzo yi humesela erivaleni leswaku ntsheketo wu fuwile hi vutlhari bya swikwembu swa le hansi, lebyi nga pfunaka eka swiphiqo swa vurhangeri bya sweswi. Dyondzo yi nga va na nkoka eka varhangeri na vatirhikulorhi va vona va xiyimo xa le hansi. Swiringanyeto na swibumabumelo swi nyikiwile eka varhangeri va sweswi ku va pfuna ku teka xiboho xo hundzuluxa switirateji swa vona swa mbulavurisano na ku cinca mavulavulelo ya vona. Varhangeri va sweswi va fanele va kopela ku suka eka vutlhari lebyi nga kona eka marungula ya tiprosi ku kambisisa ku kayivela ka swikili swa vona swa vulawuri na switirateji swa mbulavurisano ku antswisa mbulavurisano exikarhi ka vona na vatirhikulorhi va vona lava nga eka xiyimo xa le hansi. / Ngudo i todisisa vhutali vhu re hone kha nganetshelo dza phurosa ya sialala ya Xitsonga malugana na khaedu ya zwikili zwa ndangulo na ndila dza vhudavhidzani zwi shumiswaho nga vharangaphanda vha musalauno zwitshavhani. Mafhungo a u rangela malugana na vhudavhidzani ha phukha na ha vhathu o netshedzwa ho sedzwa maitele na zwikili zwa vhurangaphanda. Nganetshelo dzo vhulungwaho na u nanguludzwa dza phurosa ya sialala ya Xitsonga na nganetshelo malugana na vharangaphanda vha musalauno dzo kuvhanganywa dza senguluswa. Ngudo iyi yo disendeka kha ndila dza Tsenguluso ya Vhudavhidzani ha Tsasaladzo, Ngudo ya luambo ho sedzwa zwa u Tshilisana kha Vhudavhidzani na Nzudzanyele ya Vhushaka ha vhathu. Data yo vhekanywa u ya nga zwigwada zwa ndila dza vhudavhidzani dza u amba na dzi si dza u amba. Maitele a u davhidzana a vhaanewa kha vhuimo ha vhurangaphanda kha nganetshelo dza phurosa dza sialala na kha zwitshavha zwa musalauno o talutshedzwa a senguluswa ho d isendekwa nga ndila dzo nangwaho. Mawanwa o dzumbulula uri nangoho, vharangaphanda vha musalauno vha shaya zwikili zwa ndangulo na ndila dza vhudavhidzani. Mirando ya vhurangaphanda yo tolwaho ine ya lavhelelwa kha vharangaphanda vhanzhi vha zwitshavha a vha nayo. Zwiwo zwa ndangulo na u laula zwa u shumisa maanda kha tshivhumbeo tsha u shumisa kana u tutuwedza hu sa vhuedzi zwo vhonala kha tshumiso i si yone ya ndila dza vhudavhidzani dza u amba na dzi si dza u amba. Tseda, tsinyuwo na lutendo lwa vhurereli vhu si hone kana vha kale zwo vha zwiko zwa ndangulommbi na u toda u laula. Vhunzhi ha vhalanda vho vhaisala muyani, kha u amba na u tambudzwa muvhilini, vho tambudzwa kha zwa vhudzekani na u sudzuluswa nga vharangaphanda vhavho tshitshavhani. Vharangaphanda vha musalauno vha nga guda zwinzhi nga ha zwikili zwa ndangulo na ndila dza vhudavhidzani kha nganetshelo dza phurosa ya sialala ya nyambo dza vharema, zwihulu kha nganetshelo dza phurosa ya sialala ya Xitsonga. Ngudo yo bvukulula uri zwa sialala zwo pfuma nga vhutali ha vha kale, vhune vhu nga thusa malugana na thaidzo dza vhurangaphanda ha musalauno. Ngudo iyi i nga vha ya ndeme kha vharangaphanda na vhalanda vhavho. Madzinginywa na themendelo zwo netshedzwa kha vharangaphanda vha musalauno u vha thusa uri vha kone u tshea malugana na u dzudzanya nga huswa ndila dzavho dza vhudavhidzani, nahone vha kone u shandukisa kuitele kwavho kwa u davhidzana. Vharangaphanda vha muisalauno vha fanela u guda kha vhutali vhu re kha nganetshelo dza phurosa ya sialala vha lulamise tshiimo tsha u shaya havho zwikili zwa ndangulo na nd ila dza vhudavhidzani malugana na u khwinisa vhudavhidzani vhukati havho na vhalanda vhavho. / The study investigates the wisdom embedded in Xitsonga oral prose narratives to address management skills and communication strategies used by current leaders in societies. Background information on animal and human communication is provided with a focus on leadership styles and skills. Selected documented Xitsonga oral prose narratives and narratives about current leaders were collected and analysed. The study is guided by the Critical Discourse Analysis, Interactional Sociolinguistics and Social Constructionist approaches. Data was classified per the selected categories of the verbal and nonverbal communication strategies. Communicative behaviours of characters in leadership positions in the oral prose narratives and those of the current societies were interpreted and analysed based on the selected approaches. Findings revealed that indeed, current leaders lack management skills and communication strategies. Examined leadership principles expected from many societal leaders were found to be non-existent. Cases of power mismanagement and dominance in the form of negative manipulation or influence were identified from their misuse of verbal and nonverbal communication strategies. Greed, anger and defective religious or ancestral beliefs were sources of such power mismanagement and dominance. Most subordinates suffered emotional, verbal and physical abuse, sexual harassment and displacement at the hands of their leaders in the society. Current leaders can learn much about management skills and communication strategies from the African languages oral prose narratives, particularly Xitsonga oral prose narratives. The study reveals that folklore is rich with ancestral wisdom, which can assist in current leadership problems. The study can be valuable to both leaders and their subordinates. Suggestions and recommendations are offered to the current leaders to help them decide on adjusting their communication strategies and ultimately changing their communicative behaviour. Current leaders should take a leaf from the wisdom embedded in oral prose narratives to address their lack of management skills and communication strategies to improve communication between them and their subordinates. / African Languages / D. Litt. et Phil. (African Languages)

Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode. / Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.