New ac dc power factor correction architecture suitable for high frequency op...Asoka Technologies
This paper presents a novel ac-dc power factor correction (PFC) power conversion architecture for single-phase grid interface. The proposed architecture has significant advantages for achieving high efficiency, good power factor, and converter miniaturization, especially in low-to-medium power applications. The architecture enables twice-line-frequency energy to be buffered at high voltage with a large voltage swing, enabling reduction in the energy buffer capacitor size, and elimination of electrolytic capacitors. While this architecture can be beneficial with a variety of converter topologies, it is especially suited for system miniaturization by enabling designs that operate at high frequency (HF, 3 – 30 MHz). Moreover, we introduce circuit implementations that provide efficient operation in this range. The proposed approach is demonstrated for an LED driver converter operating at a (variable) HF switching frequency (3 – 10 MHz) from 120Vac, and supplying a 35Vdc output at up to 30W. The prototype converter achieves high efficiency (92 %) and power factor (0.89), and maintains good performance over a wide load range. Owing to architecture and HF operation, the prototype achieves a high ‘box’ power density of 50W/ in3 (‘displacement’ power density of 130W/ in3), with miniaturized inductors, ceramic energy buffer capacitors, and a small-volume EMI filter.
Information about the film-project "Kinshasa Symphony". A documentary about the only symphonyorchestra in central africa: L'Orchestre Symphonique Kimbanguiste. More information: www.kinshasa-symphony.com
New ac dc power factor correction architecture suitable for high frequency op...Asoka Technologies
This paper presents a novel ac-dc power factor correction (PFC) power conversion architecture for single-phase grid interface. The proposed architecture has significant advantages for achieving high efficiency, good power factor, and converter miniaturization, especially in low-to-medium power applications. The architecture enables twice-line-frequency energy to be buffered at high voltage with a large voltage swing, enabling reduction in the energy buffer capacitor size, and elimination of electrolytic capacitors. While this architecture can be beneficial with a variety of converter topologies, it is especially suited for system miniaturization by enabling designs that operate at high frequency (HF, 3 – 30 MHz). Moreover, we introduce circuit implementations that provide efficient operation in this range. The proposed approach is demonstrated for an LED driver converter operating at a (variable) HF switching frequency (3 – 10 MHz) from 120Vac, and supplying a 35Vdc output at up to 30W. The prototype converter achieves high efficiency (92 %) and power factor (0.89), and maintains good performance over a wide load range. Owing to architecture and HF operation, the prototype achieves a high ‘box’ power density of 50W/ in3 (‘displacement’ power density of 130W/ in3), with miniaturized inductors, ceramic energy buffer capacitors, and a small-volume EMI filter.
Information about the film-project "Kinshasa Symphony". A documentary about the only symphonyorchestra in central africa: L'Orchestre Symphonique Kimbanguiste. More information: www.kinshasa-symphony.com
1. Norreportskolan ska ny måla vägarna i skolan
och det finns 39 vägar i skolan.en väg är 4m
bredd och 3.5m lång. Skolan har köpt färghinkar
som innehåller 3L. en liter färg räcker till 7kvm
a) hur många färghinkar behöver skolan?
b) hur många färghinkar behöver skolan om en
hink innehåller 2.5L
2. svar
a) 3.5x4=14kvm
39x14=546kvm
1 hink 3L ,1L=7kvm, 2L= 14kvm=en väg
2x39=78L
78/3=26 färg hinkar svar: 26 färg hinkar
b) 2.5L hink, 2L= 14kvm=en väg
2x39=78L
78/2.5=31,2 färg hinkar svar: 32 färg hinkar