Yi-Ping Hsieh

Novel High Step-Up DC–DC Converter With Coupled-Inductor and Switched-Capacitor Techniques

A novel high step-up dc-dc converter with coupled-inductor and switched-capacitor techniques is proposed in this paper. The capacitors are charged in parallel and are discharged in series by the coupled inductor, stacking on the output capacitor. Thus, the proposed converter can achieve high step-up voltage gain with appropriate duty ratio. Besides, the voltage spike on the main switch can be clamped. Therefore, low on-state resistance RDS(ON) of the main switch can be adopted to reduce the conduction loss. The efficiency can be improved. The operating principle and steady-state analyses are discussed in detail. Finally, a prototype circuit with 24-V input voltage, 400-V output voltage, and 200-W output power is implemented in the laboratory. Experiment results confirm the analysis and advantages of the proposed converter.

Novel High Step-Up DC–DC Converter for Distributed Generation System

In this paper, a novel high step-up dc-dc converter for distributed generation systems is proposed. The concept is to utilize two capacitors and one coupled inductor. The two capacitors are charged in parallel during the switch-off period and are discharged in series during the switch-on period by the energy stored in the coupled inductor to achieve a high step-up voltage gain. In addition, the leakage-inductor energy of the coupled inductor is recycled with a passive clamp circuit. Thus, the voltage stress on the main switch is reduced. The switch with low resistance RDS(ON) can be adopted to reduce the conduction loss. In addition, the reverse-recovery problem of the diodes is alleviated, and thus, the efficiency can be further improved. The operating principle and steady-state analyses are discussed in detail. Finally, a prototype circuit with 24-V input voltage, 400-V output voltage, and 200-W output power is implemented in the laboratory to verify the performance of the proposed converter.

Novel High Step-Up DC–DC Converter With Coupled-Inductor and Switched-Capacitor Techniques for a Sustainable Energy System

In this paper, a novel high step-up dc-dc converter is proposed for a sustainable energy system. The proposed converter uses coupled-inductor and switched-capacitor techniques. The capacitors are charged in parallel and discharged in series by the coupled inductor to achieve high step-up voltage gain with an appropriate duty ratio. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit; low on-state resistance Rds(on) of the main switch can be adopted to reduce the conduction loss. In addition, the reverse-recovery problem of the diode is alleviated by a coupled inductor. Thus, the efficiency can be further improved. The operating principle and steady-state analyses of voltage gain are discussed in detail. Finally, a prototype circuit with 24-V input voltage, 400-V output voltage, and 200-W output power is implemented in the laboratory to verify the performance of the proposed converter.

High-Conversion-Ratio Bidirectional DC–DC Converter With Coupled Inductor

In this paper, a high-conversion-ratio bidirectional dc-dc converter with coupled inductor is proposed. In the boost mode, two capacitors are parallel charged and series discharged by the coupled inductor. Thus, high step-up voltage gain can be achieved with an appropriate duty ratio. The voltage stress on the main switch is reduced by a passive clamp circuit. Therefore, the low resistance RDS(ON) of the main switch can be adopted to reduce conduction loss. In the buck mode, two capacitors are series charged and parallel discharged by the coupled inductor. The bidirectional converter can have high step-down gain. Aside from that, all of the switches achieve zero voltage-switching turn-on, and the switching loss can be improved. Due to two active clamp circuits, the energy of the leakage inductor of the coupled inductor is recycled. The efficiency can be further improved. The operating principle and the steady-state analyses of the voltage gain are discussed. Finally, a 24-V-input-voltage, 400-V-output-voltage, and 200-W-output-power prototype circuit is implemented in the laboratory to verify the performance.

Novel Three-Port Converter With High-Voltage Gain

In this paper, a novel three-port converter (TPC) with high-voltage gain for stand-alone renewable power system applications is proposed. This converter uses only three switches to achieve the power flow control. Two input sources share only one inductor. Thus, the volume can be reduced. Besides, the conversion ratio of the converter is higher than other TPCs. Thus, the degree of freedom of duty cycle is large. The converter can have a higher voltage gain for both low-voltage ports with a lower turns ratio and a reasonable duty ratio. The voltage stress of switches is low; thus, conduction loss can be further improved by adopting low Rds(on) switches. Therefore, the converter can achieve a high conversion ratio and high efficiency at the same time. The operation principles, steady-state analysis, and control method of the converter are presented and discussed. A prototype of the proposed converter with a low input voltage 24 V for photovoltaic source, a battery port voltage 48 V, and an output voltage 400 V is implemented to verify the theoretical analysis. The power flow control of the converter is also built and tested with a digital signal processor.

Potential Disparities in the Management of Schizophrenia in the United States

OBJECTIVE This study investigated whether outpatient visits to psychiatrists and primary care physicians (family physicians, general internists, or general practitioners) by individuals with schizophrenia differed in antipsychotic medication management and subsequent hospitalization by age, gender, race-ethnicity, insurance, rurality, and region. METHODS Data for the study were from office visit forms completed between 1999 and 2007 by physicians in the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey. A total of 3,359 outpatient visits by individuals with a diagnosis of schizophrenia were identified. The research team used four logistic regression models to test the relationship of sociodemographic variables to antipsychotic medication management during the visit and to hospitalization after the visit. The four models controlled for available clinical covariates with or without physician specialty in the entire cohort and in the cohort of visits in which patients had no active psychotic symptoms. RESULTS In at least three of the four models, the research team observed that visits by non-Hispanic black patients had significantly (p<.05) greater odds of involving antipsychotic medication management than visits by non-Hispanic whites (range of odds ratios [ORs] 1.66 to 1.88) and of resulting in hospitalization (range of ORs, 3.52 to 6.95). In all four models, visits by patients who lacked insurance were significantly less likely to result in hospitalization than visits by patients who had private insurance (OR=<.001 in all models). CONCLUSIONS These findings provide the first national evidence of potential treatment disparities for schizophrenia. Further research is needed to definitively identify disparities and to understand their causes and consequences.

Associations between child maltreatment, PTSD, and internet addiction among Taiwanese students

This study examines (1) the associations between multiple types of child maltreatment and Internet addiction, and (2) the mediating effects of post-traumatic stress disorder (PTSD) on these associations. We collected data from a national proportionately stratified random sample of 6233 fourth-grade students in Taiwan in 2014. We conducted bivariate correlations and sets of multiple regression analyses to examine the associations between multiple types of maltreatment (5 types in total) and Internet addiction, and to identify the mediating role of PTSD. The results reveal that being male and experiencing abuse (psychological neglect, physical neglect, paternal physical violence, sexual violence) were associated with increased risk among children of developing PTSD and Internet addiction. Moreover, PTSD mediated the associations between multiple types of maltreatment (except maternal physical violence) and Internet addiction. This study demonstrates (1) the effects of multiple types of maltreatment on the PTSD and Internet addiction of children and (2) the importance of early prevention and intervention in addressing related public-health concerns. Being male and multiple types of maltreatment were associated with PTSD and Internet addiction.PTSD mediated the associations between multiple types of maltreatment and Internet addiction.Maternal and paternal physical violence work differently on childrens risk for Internet addiction.Internet addiction can be a maladaptive coping strategy for children who suffered from maltreatment and PTSD.

A novel high step-up DC-DC converter with coupled-inductor

In this paper, a novel high step-up dc-dc converter with coupled-inductor is proposed. The proposed converter utilizes a coupled-inductor and a voltage doubler to achieve high step-up voltage gain. The voltage stress of power switch is reduced by a passive clamp circuit. Therefore, low resistance RDS(ON) of the main switch can be able to reduce conduction loss and the conversion efficiency is improved. The operating principle and steady-state analyses of voltage gain are discussed in detail. The experimental results show the voltage stresses of power source and diodes, the currents of leakage inductor, secondary-side of coupled inductor and diodes. Finally, a prototype circuit with 24-V input voltage, and 400-V output voltage, and 200-W output power is implemented in the laboratory to verify the performance.

Design and Steady-State Analysis of Parallel Resonant DC–DC Converter for High-Voltage Power Generator

A novel voltage-doubling circuit with parallel-resonant dc-dc converter is proposed. The converter consists of full-bridge inverter, resonant tank, high-frequency high-voltage transformer, and voltage-doubling circuit. In the high-voltage applications, low-output voltage ripple has been given much attention. The output voltage step-up ratio is increased by two parts. One is a high-frequency high-voltage transformer and the other is a voltage-doubling circuit. The novel voltage-doubling circuit can not only reach a higher output voltage but also reduce output ripple to a lower level than the conventional one. Therefore, while maintaining the same output voltage, the transformers turn ratio can be reduced compared with the conventional voltage-doubling circuit. The output power can be adjusted by the phase-shift control technique. In addition, combining this technique with the parallel resonant tank can make all the switches achieve zero voltage turn on (ZVS). The operating principles, steady-state analysis, and the parameter designs are discussed in this paper. Finally, a prototype circuit with 400-V input voltage, 40-kV output voltage, and 300-W output power is developed in the laboratory to verify the performance of the proposed converter.

A novel active clamp high step-up DC-DC converter with coupled-inductor for fuel cell system

A novel high step-up DC-DC converter for fuel cell (FC) system is proposed in this paper. By utilizing the coupled-inductor, energy can be transfer to secondary side and charge step-up capacitor at the duration of magnetizing inductor are charged by input voltage. Part of leakage inductor energy charge clamp capacitor and convert to step-up capacitor. High step-up voltage gain and high efficiency can be achieved by input voltage, step-up capacitor and the secondary side output with an appropriate duty ratio. By using active clamp technique, voltage spike of main switch can be reduced and the leakage inductance energy can be recycled. However, the leakage inductor induces large voltage spike on main switch when it turns off. The voltage spike on the main switch are reduced by an active clamp circuit. Therefore, low switch-turn-on resistance RDS(ON) for the main switch can reduce conduction loss. In addition, high switching frequency designed reduces the physical volume. The operating principle and steady-state analyses of Continuous Conduction Mode (CCM) of the voltage gain are also discussed in detail. Finally, experimental results taken from a 200-W prototype circuit with a 24-V input voltage and 400-V output voltage are reported to verify the performance of the proposed converter.