For more than a century it has been known that signals and power can be transferred electromagnetically. This knowledge has motivated substantial research and development into wireless signal transmission which today is competitive with traditional conductive cabling systems. Power transfer across air gaps, however, has seen more modest development and has tended to be restricted to electric machines that have tight magnetic couplings. It is only very recently that a novel technique termed IPT (Inductive Power Transfer) has made power delivery to movable objects across large air gaps a practical reality. A typical IPT system comprises a primary power converter supplying high frequency alternating current to a conductive track loop with multiple secondary power pick-up circuits loosely coupled to it. IPT employs modern power conversion, control, and magnetic coupling techniques to achieve clean and reliable power transfer without direct electrical contact. Many practical applications have been found for IPT in materials handing, lighting, and transportation systems. One of the major constraints, however, is the primary power supply, particularly at high power levels and when power transfer over large distances is required. In this thesis selected resonant converters suitable for IPT power supplies are investigated using mathematical analysis, computer simulations and practical experiments. The basic characteristics and underlying principles of the converters are studied in order to determine their dynamic performance and power transfer capability. Special attention is given to improving existing IPT power supplies while investigating new power converters in order to achieve high efficiency and reliable operation at reduced cost. The current-fed parallel resonant converter power supply has been the basis of most commercial applications to date. It has a high efficiency and produces good voltage and current waveforms. However, both the track length that it can drive and the power level it can operate at are limited and the system may vary in frequency if the track resonant circuit and the pick-up load are not carefully designed. As a result, this supply, in its simple form, is only suitable for short track lengths and low power applications. The voltage-fed series ii quasi-resonant converter power supply controls the frequency directly and is capable of driving longer track lengths as a result of series compensation employed in the track loop. However, its voltage and current waveforms contain more harmonics, and while high efficiency may be achieved with soft switching, the condition is very dependent on the track compensation and is difficult to meet during start-up and shut down transients. In consequence, this supply is suitable for medium track lengths and medium power level applications. Improved current-fed and voltage-fed IPT power supplies are proposed in this thesis. They have the most preferred track current properties, including constant magnitude and nearly pure sine wave characteristics. Despite the circuit complexity and high system cost involved, these supplies are ideally suitable for long track lengths and high power applications. A novel converter based on free oscillation and energy injection control is also presented and shown to be capable of achieving high frequency AC power generation at very low switching frequencies while reducing the system cost. As such it is appealing for long track length, high track current, high frequency, and low voltage source applications. Finally, a very simple converter based on self-sustained oscillation without an external controller is demonstrated at low operating voltages, and a cost-effective option to overcome the start-up problems exhibited by most IPT power supplies at high voltages is shown with excellent dynamic zero voltage switching performance. / Whole document restricted, but available by request, use the feedback form to request access.

For more than a century it has been known that signals and power can be transferred electromagnetically. This knowledge has motivated substantial research and development into wireless signal transmission which today is competitive with traditional conductive cabling systems. Power transfer across air gaps, however, has seen more modest development and has tended to be restricted to electric machines that have tight magnetic couplings. It is only very recently that a novel technique termed IPT (Inductive Power Transfer) has made power delivery to movable objects across large air gaps a practical reality. A typical IPT system comprises a primary power converter supplying high frequency alternating current to a conductive track loop with multiple secondary power pick-up circuits loosely coupled to it. IPT employs modern power conversion, control, and magnetic coupling techniques to achieve clean and reliable power transfer without direct electrical contact. Many practical applications have been found for IPT in materials handing, lighting, and transportation systems. One of the major constraints, however, is the primary power supply, particularly at high power levels and when power transfer over large distances is required. In this thesis selected resonant converters suitable for IPT power supplies are investigated using mathematical analysis, computer simulations and practical experiments. The basic characteristics and underlying principles of the converters are studied in order to determine their dynamic performance and power transfer capability. Special attention is given to improving existing IPT power supplies while investigating new power converters in order to achieve high efficiency and reliable operation at reduced cost. The current-fed parallel resonant converter power supply has been the basis of most commercial applications to date. It has a high efficiency and produces good voltage and current waveforms. However, both the track length that it can drive and the power level it can operate at are limited and the system may vary in frequency if the track resonant circuit and the pick-up load are not carefully designed. As a result, this supply, in its simple form, is only suitable for short track lengths and low power applications. The voltage-fed series ii quasi-resonant converter power supply controls the frequency directly and is capable of driving longer track lengths as a result of series compensation employed in the track loop. However, its voltage and current waveforms contain more harmonics, and while high efficiency may be achieved with soft switching, the condition is very dependent on the track compensation and is difficult to meet during start-up and shut down transients. In consequence, this supply is suitable for medium track lengths and medium power level applications. Improved current-fed and voltage-fed IPT power supplies are proposed in this thesis. They have the most preferred track current properties, including constant magnitude and nearly pure sine wave characteristics. Despite the circuit complexity and high system cost involved, these supplies are ideally suitable for long track lengths and high power applications. A novel converter based on free oscillation and energy injection control is also presented and shown to be capable of achieving high frequency AC power generation at very low switching frequencies while reducing the system cost. As such it is appealing for long track length, high track current, high frequency, and low voltage source applications. Finally, a very simple converter based on self-sustained oscillation without an external controller is demonstrated at low operating voltages, and a cost-effective option to overcome the start-up problems exhibited by most IPT power supplies at high voltages is shown with excellent dynamic zero voltage switching performance. / Whole document restricted, but available by request, use the feedback form to request access.

Analytical techniques are developed for predicting the performance of outdoor and in-building DS-CDMA mobile radio systems and fixed services sharing the same spectrum. The mobile radio and inter-system propagation characteristics are represented by a log-normally distributed distance dependent path-loss. For simplicity, the received signal variability attributable to multi-path fading is ignored. The mobile radio system performance is estimated using outage probability expressions, where an outage is defined to occur when the momentary BER exceeds a specified threshold rate. The in-building and outdoor mobile radio systems are assumed to use power control and the composite interference is assumed to be Gaussian distributed at the mobile radio receivers. Outage probability expressions which predict the performance of a fixed service sharing spectrum with a mobile radio system are developed. The fixed service is assumed to experience occasional multi-path fading attributable to unusual tropospheric conditions. The maximum tolerable mobile radio interference at a fixed service receiver depends on the performance requirements of the service. However a commonly used Standard which requires that the INR is less than -16dB has been adopted in this Thesis, and therefore an outage is defined to occur when the CNR ratio is less than the minimum required for reliable reception, or when the INR exceeds -16dB. Sufficient electromagnetic isolation between fixed and mobile systems sharing the same spectrum may be achieved using excision suppression techniques or by geographically separating the two systems. Excision suppression techniques will have a detrimental effect on the performance of a mobile radio system unless the fixed service signal is sufficiently narrow-band. The geographical separation distances required for spectrum sharing between fixed services, and outdoor and in-building DS-CDMA mobile radio systems are presented. The fixed services are assumed to be similar to those operating in New Zealand in the 1.7-2.3 GHz frequency bands. Mobile radio systems with 5, 10, 15 and 48 MHz channels are considered. It is shown that, for the systems considered, the geographical separation required between the two systems depends largely on the mobile radio and inter-system propagation characteristics, and the mobile radio and fixed service transmission powers. / Subscription resource available via Digital Dissertations only.

For more than a century it has been known that signals and power can be transferred electromagnetically. This knowledge has motivated substantial research and development into wireless signal transmission which today is competitive with traditional conductive cabling systems. Power transfer across air gaps, however, has seen more modest development and has tended to be restricted to electric machines that have tight magnetic couplings. It is only very recently that a novel technique termed IPT (Inductive Power Transfer) has made power delivery to movable objects across large air gaps a practical reality. A typical IPT system comprises a primary power converter supplying high frequency alternating current to a conductive track loop with multiple secondary power pick-up circuits loosely coupled to it. IPT employs modern power conversion, control, and magnetic coupling techniques to achieve clean and reliable power transfer without direct electrical contact. Many practical applications have been found for IPT in materials handing, lighting, and transportation systems. One of the major constraints, however, is the primary power supply, particularly at high power levels and when power transfer over large distances is required. In this thesis selected resonant converters suitable for IPT power supplies are investigated using mathematical analysis, computer simulations and practical experiments. The basic characteristics and underlying principles of the converters are studied in order to determine their dynamic performance and power transfer capability. Special attention is given to improving existing IPT power supplies while investigating new power converters in order to achieve high efficiency and reliable operation at reduced cost. The current-fed parallel resonant converter power supply has been the basis of most commercial applications to date. It has a high efficiency and produces good voltage and current waveforms. However, both the track length that it can drive and the power level it can operate at are limited and the system may vary in frequency if the track resonant circuit and the pick-up load are not carefully designed. As a result, this supply, in its simple form, is only suitable for short track lengths and low power applications. The voltage-fed series ii quasi-resonant converter power supply controls the frequency directly and is capable of driving longer track lengths as a result of series compensation employed in the track loop. However, its voltage and current waveforms contain more harmonics, and while high efficiency may be achieved with soft switching, the condition is very dependent on the track compensation and is difficult to meet during start-up and shut down transients. In consequence, this supply is suitable for medium track lengths and medium power level applications. Improved current-fed and voltage-fed IPT power supplies are proposed in this thesis. They have the most preferred track current properties, including constant magnitude and nearly pure sine wave characteristics. Despite the circuit complexity and high system cost involved, these supplies are ideally suitable for long track lengths and high power applications. A novel converter based on free oscillation and energy injection control is also presented and shown to be capable of achieving high frequency AC power generation at very low switching frequencies while reducing the system cost. As such it is appealing for long track length, high track current, high frequency, and low voltage source applications. Finally, a very simple converter based on self-sustained oscillation without an external controller is demonstrated at low operating voltages, and a cost-effective option to overcome the start-up problems exhibited by most IPT power supplies at high voltages is shown with excellent dynamic zero voltage switching performance. / Whole document restricted, but available by request, use the feedback form to request access.

Analytical techniques are developed for predicting the performance of outdoor and in-building DS-CDMA mobile radio systems and fixed services sharing the same spectrum. The mobile radio and inter-system propagation characteristics are represented by a log-normally distributed distance dependent path-loss. For simplicity, the received signal variability attributable to multi-path fading is ignored. The mobile radio system performance is estimated using outage probability expressions, where an outage is defined to occur when the momentary BER exceeds a specified threshold rate. The in-building and outdoor mobile radio systems are assumed to use power control and the composite interference is assumed to be Gaussian distributed at the mobile radio receivers. Outage probability expressions which predict the performance of a fixed service sharing spectrum with a mobile radio system are developed. The fixed service is assumed to experience occasional multi-path fading attributable to unusual tropospheric conditions. The maximum tolerable mobile radio interference at a fixed service receiver depends on the performance requirements of the service. However a commonly used Standard which requires that the INR is less than -16dB has been adopted in this Thesis, and therefore an outage is defined to occur when the CNR ratio is less than the minimum required for reliable reception, or when the INR exceeds -16dB. Sufficient electromagnetic isolation between fixed and mobile systems sharing the same spectrum may be achieved using excision suppression techniques or by geographically separating the two systems. Excision suppression techniques will have a detrimental effect on the performance of a mobile radio system unless the fixed service signal is sufficiently narrow-band. The geographical separation distances required for spectrum sharing between fixed services, and outdoor and in-building DS-CDMA mobile radio systems are presented. The fixed services are assumed to be similar to those operating in New Zealand in the 1.7-2.3 GHz frequency bands. Mobile radio systems with 5, 10, 15 and 48 MHz channels are considered. It is shown that, for the systems considered, the geographical separation required between the two systems depends largely on the mobile radio and inter-system propagation characteristics, and the mobile radio and fixed service transmission powers. / Subscription resource available via Digital Dissertations only.

For more than a century it has been known that signals and power can be transferred electromagnetically. This knowledge has motivated substantial research and development into wireless signal transmission which today is competitive with traditional conductive cabling systems. Power transfer across air gaps, however, has seen more modest development and has tended to be restricted to electric machines that have tight magnetic couplings. It is only very recently that a novel technique termed IPT (Inductive Power Transfer) has made power delivery to movable objects across large air gaps a practical reality. A typical IPT system comprises a primary power converter supplying high frequency alternating current to a conductive track loop with multiple secondary power pick-up circuits loosely coupled to it. IPT employs modern power conversion, control, and magnetic coupling techniques to achieve clean and reliable power transfer without direct electrical contact. Many practical applications have been found for IPT in materials handing, lighting, and transportation systems. One of the major constraints, however, is the primary power supply, particularly at high power levels and when power transfer over large distances is required. In this thesis selected resonant converters suitable for IPT power supplies are investigated using mathematical analysis, computer simulations and practical experiments. The basic characteristics and underlying principles of the converters are studied in order to determine their dynamic performance and power transfer capability. Special attention is given to improving existing IPT power supplies while investigating new power converters in order to achieve high efficiency and reliable operation at reduced cost. The current-fed parallel resonant converter power supply has been the basis of most commercial applications to date. It has a high efficiency and produces good voltage and current waveforms. However, both the track length that it can drive and the power level it can operate at are limited and the system may vary in frequency if the track resonant circuit and the pick-up load are not carefully designed. As a result, this supply, in its simple form, is only suitable for short track lengths and low power applications. The voltage-fed series ii quasi-resonant converter power supply controls the frequency directly and is capable of driving longer track lengths as a result of series compensation employed in the track loop. However, its voltage and current waveforms contain more harmonics, and while high efficiency may be achieved with soft switching, the condition is very dependent on the track compensation and is difficult to meet during start-up and shut down transients. In consequence, this supply is suitable for medium track lengths and medium power level applications. Improved current-fed and voltage-fed IPT power supplies are proposed in this thesis. They have the most preferred track current properties, including constant magnitude and nearly pure sine wave characteristics. Despite the circuit complexity and high system cost involved, these supplies are ideally suitable for long track lengths and high power applications. A novel converter based on free oscillation and energy injection control is also presented and shown to be capable of achieving high frequency AC power generation at very low switching frequencies while reducing the system cost. As such it is appealing for long track length, high track current, high frequency, and low voltage source applications. Finally, a very simple converter based on self-sustained oscillation without an external controller is demonstrated at low operating voltages, and a cost-effective option to overcome the start-up problems exhibited by most IPT power supplies at high voltages is shown with excellent dynamic zero voltage switching performance. / Whole document restricted, but available by request, use the feedback form to request access.

Analytical techniques are developed for predicting the performance of outdoor and in-building DS-CDMA mobile radio systems and fixed services sharing the same spectrum. The mobile radio and inter-system propagation characteristics are represented by a log-normally distributed distance dependent path-loss. For simplicity, the received signal variability attributable to multi-path fading is ignored. The mobile radio system performance is estimated using outage probability expressions, where an outage is defined to occur when the momentary BER exceeds a specified threshold rate. The in-building and outdoor mobile radio systems are assumed to use power control and the composite interference is assumed to be Gaussian distributed at the mobile radio receivers. Outage probability expressions which predict the performance of a fixed service sharing spectrum with a mobile radio system are developed. The fixed service is assumed to experience occasional multi-path fading attributable to unusual tropospheric conditions. The maximum tolerable mobile radio interference at a fixed service receiver depends on the performance requirements of the service. However a commonly used Standard which requires that the INR is less than -16dB has been adopted in this Thesis, and therefore an outage is defined to occur when the CNR ratio is less than the minimum required for reliable reception, or when the INR exceeds -16dB. Sufficient electromagnetic isolation between fixed and mobile systems sharing the same spectrum may be achieved using excision suppression techniques or by geographically separating the two systems. Excision suppression techniques will have a detrimental effect on the performance of a mobile radio system unless the fixed service signal is sufficiently narrow-band. The geographical separation distances required for spectrum sharing between fixed services, and outdoor and in-building DS-CDMA mobile radio systems are presented. The fixed services are assumed to be similar to those operating in New Zealand in the 1.7-2.3 GHz frequency bands. Mobile radio systems with 5, 10, 15 and 48 MHz channels are considered. It is shown that, for the systems considered, the geographical separation required between the two systems depends largely on the mobile radio and inter-system propagation characteristics, and the mobile radio and fixed service transmission powers. / Subscription resource available via Digital Dissertations only.

For more than a century it has been known that signals and power can be transferred electromagnetically. This knowledge has motivated substantial research and development into wireless signal transmission which today is competitive with traditional conductive cabling systems. Power transfer across air gaps, however, has seen more modest development and has tended to be restricted to electric machines that have tight magnetic couplings. It is only very recently that a novel technique termed IPT (Inductive Power Transfer) has made power delivery to movable objects across large air gaps a practical reality. A typical IPT system comprises a primary power converter supplying high frequency alternating current to a conductive track loop with multiple secondary power pick-up circuits loosely coupled to it. IPT employs modern power conversion, control, and magnetic coupling techniques to achieve clean and reliable power transfer without direct electrical contact. Many practical applications have been found for IPT in materials handing, lighting, and transportation systems. One of the major constraints, however, is the primary power supply, particularly at high power levels and when power transfer over large distances is required. In this thesis selected resonant converters suitable for IPT power supplies are investigated using mathematical analysis, computer simulations and practical experiments. The basic characteristics and underlying principles of the converters are studied in order to determine their dynamic performance and power transfer capability. Special attention is given to improving existing IPT power supplies while investigating new power converters in order to achieve high efficiency and reliable operation at reduced cost. The current-fed parallel resonant converter power supply has been the basis of most commercial applications to date. It has a high efficiency and produces good voltage and current waveforms. However, both the track length that it can drive and the power level it can operate at are limited and the system may vary in frequency if the track resonant circuit and the pick-up load are not carefully designed. As a result, this supply, in its simple form, is only suitable for short track lengths and low power applications. The voltage-fed series ii quasi-resonant converter power supply controls the frequency directly and is capable of driving longer track lengths as a result of series compensation employed in the track loop. However, its voltage and current waveforms contain more harmonics, and while high efficiency may be achieved with soft switching, the condition is very dependent on the track compensation and is difficult to meet during start-up and shut down transients. In consequence, this supply is suitable for medium track lengths and medium power level applications. Improved current-fed and voltage-fed IPT power supplies are proposed in this thesis. They have the most preferred track current properties, including constant magnitude and nearly pure sine wave characteristics. Despite the circuit complexity and high system cost involved, these supplies are ideally suitable for long track lengths and high power applications. A novel converter based on free oscillation and energy injection control is also presented and shown to be capable of achieving high frequency AC power generation at very low switching frequencies while reducing the system cost. As such it is appealing for long track length, high track current, high frequency, and low voltage source applications. Finally, a very simple converter based on self-sustained oscillation without an external controller is demonstrated at low operating voltages, and a cost-effective option to overcome the start-up problems exhibited by most IPT power supplies at high voltages is shown with excellent dynamic zero voltage switching performance. / Whole document restricted, but available by request, use the feedback form to request access.

Analytical techniques are developed for predicting the performance of outdoor and in-building DS-CDMA mobile radio systems and fixed services sharing the same spectrum. The mobile radio and inter-system propagation characteristics are represented by a log-normally distributed distance dependent path-loss. For simplicity, the received signal variability attributable to multi-path fading is ignored. The mobile radio system performance is estimated using outage probability expressions, where an outage is defined to occur when the momentary BER exceeds a specified threshold rate. The in-building and outdoor mobile radio systems are assumed to use power control and the composite interference is assumed to be Gaussian distributed at the mobile radio receivers. Outage probability expressions which predict the performance of a fixed service sharing spectrum with a mobile radio system are developed. The fixed service is assumed to experience occasional multi-path fading attributable to unusual tropospheric conditions. The maximum tolerable mobile radio interference at a fixed service receiver depends on the performance requirements of the service. However a commonly used Standard which requires that the INR is less than -16dB has been adopted in this Thesis, and therefore an outage is defined to occur when the CNR ratio is less than the minimum required for reliable reception, or when the INR exceeds -16dB. Sufficient electromagnetic isolation between fixed and mobile systems sharing the same spectrum may be achieved using excision suppression techniques or by geographically separating the two systems. Excision suppression techniques will have a detrimental effect on the performance of a mobile radio system unless the fixed service signal is sufficiently narrow-band. The geographical separation distances required for spectrum sharing between fixed services, and outdoor and in-building DS-CDMA mobile radio systems are presented. The fixed services are assumed to be similar to those operating in New Zealand in the 1.7-2.3 GHz frequency bands. Mobile radio systems with 5, 10, 15 and 48 MHz channels are considered. It is shown that, for the systems considered, the geographical separation required between the two systems depends largely on the mobile radio and inter-system propagation characteristics, and the mobile radio and fixed service transmission powers. / Subscription resource available via Digital Dissertations only.

Analytical techniques are developed for predicting the performance of outdoor and in-building DS-CDMA mobile radio systems and fixed services sharing the same spectrum. The mobile radio and inter-system propagation characteristics are represented by a log-normally distributed distance dependent path-loss. For simplicity, the received signal variability attributable to multi-path fading is ignored. The mobile radio system performance is estimated using outage probability expressions, where an outage is defined to occur when the momentary BER exceeds a specified threshold rate. The in-building and outdoor mobile radio systems are assumed to use power control and the composite interference is assumed to be Gaussian distributed at the mobile radio receivers. Outage probability expressions which predict the performance of a fixed service sharing spectrum with a mobile radio system are developed. The fixed service is assumed to experience occasional multi-path fading attributable to unusual tropospheric conditions. The maximum tolerable mobile radio interference at a fixed service receiver depends on the performance requirements of the service. However a commonly used Standard which requires that the INR is less than -16dB has been adopted in this Thesis, and therefore an outage is defined to occur when the CNR ratio is less than the minimum required for reliable reception, or when the INR exceeds -16dB. Sufficient electromagnetic isolation between fixed and mobile systems sharing the same spectrum may be achieved using excision suppression techniques or by geographically separating the two systems. Excision suppression techniques will have a detrimental effect on the performance of a mobile radio system unless the fixed service signal is sufficiently narrow-band. The geographical separation distances required for spectrum sharing between fixed services, and outdoor and in-building DS-CDMA mobile radio systems are presented. The fixed services are assumed to be similar to those operating in New Zealand in the 1.7-2.3 GHz frequency bands. Mobile radio systems with 5, 10, 15 and 48 MHz channels are considered. It is shown that, for the systems considered, the geographical separation required between the two systems depends largely on the mobile radio and inter-system propagation characteristics, and the mobile radio and fixed service transmission powers. / Subscription resource available via Digital Dissertations only.