Reliability is a persistent challenge in power electronics, with component failures significantly compromising system performance. Capacitors, widely used in power converters for filtering, contribute to approximately...Reliability is a persistent challenge in power electronics, with component failures significantly compromising system performance. Capacitors, widely used in power converters for filtering, contribute to approximately 30% of failures, predominantly due to electrochemical corrosion leading to capacitance degradation and catastrophic breakdowns. This paper presents a novel capacitor-free solid-state power filter(SSPF) for three-phase inverters, offering a transformative approach to mitigate reliability issues associated with conventional inductor-capacitor(LC) and active output filters(AOFs). Unlike AOFs, which depend on compact LC structures, the SSPF eliminates capacitors entirely, circumventing their inherent failure modes. Leveraging advanced solid-state devices and transformer technology, the SSPF achieves superior filtering performance, enhances system reliability, and significantly reduces component count, utilizing half the metal-oxidesemiconductor field effect transistor(MOSFET) switches required by AOFs. This design not only lowers costs but also improves efficiency. Simulation and experimental results demonstrate the SSPF's capability to deliver a sinusoidal output voltage at the fundamental frequency. These attributes position the SSPF as a robust, cost-effective, and innovative solution for modern power electronics applications.展开更多
Biology is governed by macromolecular interactions,perturbation of which often lies at the heart of disease.Most therapeutic drugs,whether they are small molecules or biologics,exert their effects through impeding suc...Biology is governed by macromolecular interactions,perturbation of which often lies at the heart of disease.Most therapeutic drugs,whether they are small molecules or biologics,exert their effects through impeding such interactions,whether they are of an enzyme with its substrate or a ligand with its receptor.Conversely,a handful of approved drugs and a larger number of candidates in development have the opposite effect:They either activate or inhibit a biological output by stabilizing a preexisting complex through reducing the rate at which its components dissociate(koff).展开更多
Converters rely on passive filtering as a crucial element due to the high-frequency operational characteristics of power electronics.Traditional filtering methods involve a dual inductor-capacitor(LC)cell or an induct...Converters rely on passive filtering as a crucial element due to the high-frequency operational characteristics of power electronics.Traditional filtering methods involve a dual inductor-capacitor(LC)cell or an inductor-capacitor-inductor(LCL)T-circuit.However,capacitors are susceptible to wear-out mechanisms and failure modes.Nevertheless,the necessity for monitoring and regular replacement adds to an elevated cost of ownership for such systems.The utilization of an active output power filter can be used to diminish the dimensions of the LC filter and the electrolytic dc-link capacitor,even though the inclusion of capacitors remains an indispensable part of the system.This paper introduces capacitorless solid-state power filter(SSPF)for single-phase dc-ac converters.The proposed configuration is capable of generating a sinusoidal ac voltage without relying on capacitors.The proposed filter,composed of a planar transformer and an H-bridge converter operating at high frequency,injects voltage harmonics to attain a sinusoidal output voltage.The design parameters of the planar transformer are incorporated,and the impact of magnetizing and leakage inductances on the operation of the SSPF is illustrated.Theoretical analysis,supported by simulation and experimental results,are provided for a design example for a single-phase system.The total harmonic distortion observed in the output voltage is well below the IEEE 519 standard.The system operation is experimentally tested under both steady-state and dynamic conditions.A comparison with existing technology is presented,demonstrating that the proposed topology reduces the passive components used for filtering.展开更多
It is concluded that Communicative Language Teaching(CLT) is a more practical approach to develop communication ability. In the process of applying this approach on oral communication ability, techniques based on CLT ...It is concluded that Communicative Language Teaching(CLT) is a more practical approach to develop communication ability. In the process of applying this approach on oral communication ability, techniques based on CLT are explored and classified as structured output activities and communicative output activities.展开更多
基金curruntly supported by the Purdue University Office of Technology Commercialization under Track Code (PRF 71167-01)。
文摘Reliability is a persistent challenge in power electronics, with component failures significantly compromising system performance. Capacitors, widely used in power converters for filtering, contribute to approximately 30% of failures, predominantly due to electrochemical corrosion leading to capacitance degradation and catastrophic breakdowns. This paper presents a novel capacitor-free solid-state power filter(SSPF) for three-phase inverters, offering a transformative approach to mitigate reliability issues associated with conventional inductor-capacitor(LC) and active output filters(AOFs). Unlike AOFs, which depend on compact LC structures, the SSPF eliminates capacitors entirely, circumventing their inherent failure modes. Leveraging advanced solid-state devices and transformer technology, the SSPF achieves superior filtering performance, enhances system reliability, and significantly reduces component count, utilizing half the metal-oxidesemiconductor field effect transistor(MOSFET) switches required by AOFs. This design not only lowers costs but also improves efficiency. Simulation and experimental results demonstrate the SSPF's capability to deliver a sinusoidal output voltage at the fundamental frequency. These attributes position the SSPF as a robust, cost-effective, and innovative solution for modern power electronics applications.
文摘Biology is governed by macromolecular interactions,perturbation of which often lies at the heart of disease.Most therapeutic drugs,whether they are small molecules or biologics,exert their effects through impeding such interactions,whether they are of an enzyme with its substrate or a ligand with its receptor.Conversely,a handful of approved drugs and a larger number of candidates in development have the opposite effect:They either activate or inhibit a biological output by stabilizing a preexisting complex through reducing the rate at which its components dissociate(koff).
文摘Converters rely on passive filtering as a crucial element due to the high-frequency operational characteristics of power electronics.Traditional filtering methods involve a dual inductor-capacitor(LC)cell or an inductor-capacitor-inductor(LCL)T-circuit.However,capacitors are susceptible to wear-out mechanisms and failure modes.Nevertheless,the necessity for monitoring and regular replacement adds to an elevated cost of ownership for such systems.The utilization of an active output power filter can be used to diminish the dimensions of the LC filter and the electrolytic dc-link capacitor,even though the inclusion of capacitors remains an indispensable part of the system.This paper introduces capacitorless solid-state power filter(SSPF)for single-phase dc-ac converters.The proposed configuration is capable of generating a sinusoidal ac voltage without relying on capacitors.The proposed filter,composed of a planar transformer and an H-bridge converter operating at high frequency,injects voltage harmonics to attain a sinusoidal output voltage.The design parameters of the planar transformer are incorporated,and the impact of magnetizing and leakage inductances on the operation of the SSPF is illustrated.Theoretical analysis,supported by simulation and experimental results,are provided for a design example for a single-phase system.The total harmonic distortion observed in the output voltage is well below the IEEE 519 standard.The system operation is experimentally tested under both steady-state and dynamic conditions.A comparison with existing technology is presented,demonstrating that the proposed topology reduces the passive components used for filtering.
文摘It is concluded that Communicative Language Teaching(CLT) is a more practical approach to develop communication ability. In the process of applying this approach on oral communication ability, techniques based on CLT are explored and classified as structured output activities and communicative output activities.
