Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer...Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer (IPT) systems based on curved coils and flexible ferrite sheets may provide more flexible charging solutions for various electronic devices such as rice cookers and robot vacuum cleaners. Power repeaters are also used in IPT systems to extend wireless charging range by guiding magnetic fields to the receiving coil. The interaction of these three topics could be inspiring. In this paper, two adjustable power repeaters are applied to an IPT charging system with various curved receiving coils designed for vacuum cleaners. Two power repeaters share the identical structure as the Tx coil and could be rotated to mirror symmetrically. The input and output power are calculated by analyzing the equivalent circuit model. The self-inductance, mutual inductance, and coupling coefficient of the proposed system are obtained via finite element method simulation with variable rotating angles. Three typical IPT designs have also been simulated in ANSYS Maxwell and compared with the proposed magnetic design. The comparison indicates the enhancing feature of the passive power repeaters on coupling performance and the ability to guide the magnetic flux for better magnetic field coupling. Furthermore, two types of co-simulations defined by the power source via Simplorer are conducted to explore how much power could be transferred. The tuned system is shown to be able to provide about 32 W under 100 kHz operating frequency for charging the battery of a robot vacuum cleaner. The results from theoretical calculation and simulation align well with each other.展开更多
The effect of synergistic action of ultrasonic vibration and solidification pressure on tensile properties of vacuum counter-pressure casting ZL114 A alloys was studied systemically through testing and analyzing the t...The effect of synergistic action of ultrasonic vibration and solidification pressure on tensile properties of vacuum counter-pressure casting ZL114 A alloys was studied systemically through testing and analyzing the tensile strength and elongation subjected to different ultrasonic powers and solidification pressures. The results indicate that the synergistic action of ultrasonic vibration and solidification pressure can result in the refinement of grains and improvement of tensile properties. Both the highest tensile strength and elongation of aluminum alloy were obtained under synergistic action of 600 W ultrasonic power and 350 kPa solidification pressure. Moreover, the tensile fracture morphology shows obvious ductile fracture characteristics. When the solidification pressure is lower than 300 kPa, the effect of ultrasonic power on tensile strength and elongation is more obvious, but when the solidification pressure is higher than 300 kPa, the effect of solidification pressure on tensile strength and elongation is greater. Meanwhile, the size and morphology of the eutectic silicon were improved significantly by the ultrasonic vibration and pressurized solidification. The strip and massive eutectic silicon phase are completely converted into small short rod-like and evenly distributed Si phases at the grain boundary of primary α-Al.展开更多
When subjected to high voltages between opened contacts, vacuum interrupters may emit X-rays. In order to ensure that these are of an acceptable level, vacuum interrupters should comply with the limits for X-ray emiss...When subjected to high voltages between opened contacts, vacuum interrupters may emit X-rays. In order to ensure that these are of an acceptable level, vacuum interrupters should comply with the limits for X-ray emission and the test procedures to be carried out to verify this based on relevant standards and specifications. In this paper, a comprehensive experimental study has been performed for 126 kV vacuum interrupters used in a transmission system to understand the X-radiation level and its influence by three main parameters, namely applied power-frequency voltage, contact gap and power=frequency voltage conditioning. The radiation instrument is an FJ347 radiometer and the X-radiation dose was measured at the power-frequency test voltage. These tests demonstrated that the X-radiation emission level for a 126 kV vacuum interrupter did not exceed the following： 5 μSv per hour at a rated voltage of 126 kV and 150 μSv per hour at a power-frequency voltage of 230 kV at 1 m distance. The X-radiation dose increased with the applied power-frequency voltage increasing and decreased with the contact gap increasing. The X- radiation dose for 126 kV vacuum interrupters decreased by 57% after the conditioning procedure with a certain power-frequency voltage. During the conditioning procedure, the average value of the X-radiation dose was 4.49 mSv, which means if a professional conditions 180 interrupters per year, it will be safe at the 6.4 m distance.展开更多
文摘Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer (IPT) systems based on curved coils and flexible ferrite sheets may provide more flexible charging solutions for various electronic devices such as rice cookers and robot vacuum cleaners. Power repeaters are also used in IPT systems to extend wireless charging range by guiding magnetic fields to the receiving coil. The interaction of these three topics could be inspiring. In this paper, two adjustable power repeaters are applied to an IPT charging system with various curved receiving coils designed for vacuum cleaners. Two power repeaters share the identical structure as the Tx coil and could be rotated to mirror symmetrically. The input and output power are calculated by analyzing the equivalent circuit model. The self-inductance, mutual inductance, and coupling coefficient of the proposed system are obtained via finite element method simulation with variable rotating angles. Three typical IPT designs have also been simulated in ANSYS Maxwell and compared with the proposed magnetic design. The comparison indicates the enhancing feature of the passive power repeaters on coupling performance and the ability to guide the magnetic flux for better magnetic field coupling. Furthermore, two types of co-simulations defined by the power source via Simplorer are conducted to explore how much power could be transferred. The tuned system is shown to be able to provide about 32 W under 100 kHz operating frequency for charging the battery of a robot vacuum cleaner. The results from theoretical calculation and simulation align well with each other.
基金financially supported by the National Natural Science Foundation of China(No.51261025)the Aerospace Science and Technology Innovation Foundation of Shanghai,China(No.SAST2016046)the Key Projects of Superior Science and Technology Innovation Team of Jiangxi,China(No.20181BCB19001)
文摘The effect of synergistic action of ultrasonic vibration and solidification pressure on tensile properties of vacuum counter-pressure casting ZL114 A alloys was studied systemically through testing and analyzing the tensile strength and elongation subjected to different ultrasonic powers and solidification pressures. The results indicate that the synergistic action of ultrasonic vibration and solidification pressure can result in the refinement of grains and improvement of tensile properties. Both the highest tensile strength and elongation of aluminum alloy were obtained under synergistic action of 600 W ultrasonic power and 350 kPa solidification pressure. Moreover, the tensile fracture morphology shows obvious ductile fracture characteristics. When the solidification pressure is lower than 300 kPa, the effect of ultrasonic power on tensile strength and elongation is more obvious, but when the solidification pressure is higher than 300 kPa, the effect of solidification pressure on tensile strength and elongation is greater. Meanwhile, the size and morphology of the eutectic silicon were improved significantly by the ultrasonic vibration and pressurized solidification. The strip and massive eutectic silicon phase are completely converted into small short rod-like and evenly distributed Si phases at the grain boundary of primary α-Al.
基金supported by National Key Basic Research Program of China(973 Program)(No.2015CB251002)
文摘When subjected to high voltages between opened contacts, vacuum interrupters may emit X-rays. In order to ensure that these are of an acceptable level, vacuum interrupters should comply with the limits for X-ray emission and the test procedures to be carried out to verify this based on relevant standards and specifications. In this paper, a comprehensive experimental study has been performed for 126 kV vacuum interrupters used in a transmission system to understand the X-radiation level and its influence by three main parameters, namely applied power-frequency voltage, contact gap and power=frequency voltage conditioning. The radiation instrument is an FJ347 radiometer and the X-radiation dose was measured at the power-frequency test voltage. These tests demonstrated that the X-radiation emission level for a 126 kV vacuum interrupter did not exceed the following： 5 μSv per hour at a rated voltage of 126 kV and 150 μSv per hour at a power-frequency voltage of 230 kV at 1 m distance. The X-radiation dose increased with the applied power-frequency voltage increasing and decreased with the contact gap increasing. The X- radiation dose for 126 kV vacuum interrupters decreased by 57% after the conditioning procedure with a certain power-frequency voltage. During the conditioning procedure, the average value of the X-radiation dose was 4.49 mSv, which means if a professional conditions 180 interrupters per year, it will be safe at the 6.4 m distance.
