title: Development of a Power Factor Corrected High Current Supercapacitor Charger for a Surge Resistant UPS

authors: Zhang, Xu

subjects: High Current Charger Development

abstract: The Uninterrupted Power Supplies (UPSs) provide short term power back up to electrical loads when the mains power fail. Usually UPSs employ battery packs as the energy storage device. However the limitations of battery packs can affect the UPS performance.

As an alternative energy storage device, the supercapacitor (SC) technology is well developed over the past 30 years. Due to recent developments, single cell commercial supercapacitors are available up to about 5000 farads. Over the past 10 years, supercapacitor direct current (DC) voltage ratings have gradually increased to about 2.7 V/cell. New lithium based supercapacitor families have DC ratings up to 3.5 V/cell. For the high current applications, the supercapacitors have some advantages over batteries, which are the low effective series resistance (ESR), high power densities and high surge withstand capability. 

This thesis is a continuation of the work begun by Kozhiparambil, P. K. on Surge Resistant Uninterrupted Power Supply (SRUPS). The reason for this continual research is due to identify weaknesses in original of SRUPS work with regard to the design of the charger. To reduce the components contain, also achieve common mode transient rejection capability, a flayback mode high current charger with power factor correction has been developed for charging the SC banks. 

The prototype circuit includes multiple SC banks to transfer the energy from the 240 V, 50 Hz power line to the load maintaining high isolation level. The loads receive continuous and surge free power from the SC banks, and has electrical isolation from the main power line. An IGBT is used as a switch for the flyback charger, which has the advantage of high current capability. 

The experimental results show the design was valid for the SRUPS and it demonstrated the capability to transfer the energy through a flyback charger with power factor correction.

text: Development of a Power Factor Corrected High Current Supercapacitor Charger for a Surge Resistant UPS The Uninterrupted Power Supplies (UPSs) provide short term power back up to electrical loads when the mains power fail. Usually UPSs employ battery packs as the energy storage device. However the limitations of battery packs can affect the UPS performance.

As an alternative energy storage device, the supercapacitor (SC) technology is well developed over the past 30 years. Due to recent developments, single cell commercial supercapacitors are available up to about 5000 farads. Over the past 10 years, supercapacitor direct current (DC) voltage ratings have gradually increased to about 2.7 V/cell. New lithium based supercapacitor families have DC ratings up to 3.5 V/cell. For the high current applications, the supercapacitors have some advantages over batteries, which are the low effective series resistance (ESR), high power densities and high surge withstand capability. 

This thesis is a continuation of the work begun by Kozhiparambil, P. K. on Surge Resistant Uninterrupted Power Supply (SRUPS). The reason for this continual research is due to identify weaknesses in original of SRUPS work with regard to the design of the charger. To reduce the components contain, also achieve common mode transient rejection capability, a flayback mode high current charger with power factor correction has been developed for charging the SC banks. 

The prototype circuit includes multiple SC banks to transfer the energy from the 240 V, 50 Hz power line to the load maintaining high isolation level. The loads receive continuous and surge free power from the SC banks, and has electrical isolation from the main power line. An IGBT is used as a switch for the flyback charger, which has the advantage of high current capability. 

The experimental results show the design was valid for the SRUPS and it demonstrated the capability to transfer the energy through a flyback charger with power factor correction.

year: 2012

title: An investigation of colour discrimination with horses (Equus caballus)

authors: Blackmore, Tania Louise

subjects: chromatic discrimination

abstract: The ability of four horses (Equus caballus) to discriminate coloured (three shades of blue, green, red, and yellow) from grey (neutral density) stimuli, produced by back projected lighting filters, was investigated in a two response forced-choice procedure. Pushes of the lever in front of a coloured screen were occasionally reinforced, pushes of the lever in front of a grey screen were never reinforced. Each colour shade was randomly paired with a grey that was brighter, one that was dimmer, and one that approximately matched the colour in terms of brightness. Each horse experienced the colours in a different order, a new colour was started after 85% correct responses over five consecutive sessions or if accuracy showed no trend over sessions. All horses reached the 85% correct with blue versus grey, three horses did so with both yellow and green versus grey. All were above chance with red versus grey but none reached criterion. Further analysis showed the wavelengths of the green stimuli used overlapped with the yellow. The results are consistent with histological and behavioural studies that suggest that horses are dichromatic. They differ from some earlier data in that they indicate horses can discriminate yellow and blue, but that they may have deficiencies in discriminating red and green.

text: An investigation of colour discrimination with horses (Equus caballus) The ability of four horses (Equus caballus) to discriminate coloured (three shades of blue, green, red, and yellow) from grey (neutral density) stimuli, produced by back projected lighting filters, was investigated in a two response forced-choice procedure. Pushes of the lever in front of a coloured screen were occasionally reinforced, pushes of the lever in front of a grey screen were never reinforced. Each colour shade was randomly paired with a grey that was brighter, one that was dimmer, and one that approximately matched the colour in terms of brightness. Each horse experienced the colours in a different order, a new colour was started after 85% correct responses over five consecutive sessions or if accuracy showed no trend over sessions. All horses reached the 85% correct with blue versus grey, three horses did so with both yellow and green versus grey. All were above chance with red versus grey but none reached criterion. Further analysis showed the wavelengths of the green stimuli used overlapped with the yellow. The results are consistent with histological and behavioural studies that suggest that horses are dichromatic. They differ from some earlier data in that they indicate horses can discriminate yellow and blue, but that they may have deficiencies in discriminating red and green.

year: 2008

title: Stemming the colonial environmental tide

authors: Joseph, Robert

subjects: human activities

abstract: Stemming the colonial environmental tide supports an Aotearoa New Zealand context that fundamentally acknowledges mātauranga and tikanga Māori law and shared co-governance and concurrent jurisdiction through 7 Aotearoa New Zealand EBM principles.

text: Stemming the colonial environmental tide Stemming the colonial environmental tide supports an Aotearoa New Zealand context that fundamentally acknowledges mātauranga and tikanga Māori law and shared co-governance and concurrent jurisdiction through 7 Aotearoa New Zealand EBM principles.

year: 2022-05