Design Procedure for High-Frequency Operation of the Modified Series-Resonant APWM Converter to Reduce Size and Circulating Current

2018

Energies

This paper studies and presents a series-connected high frequency DC/DC converter connected to a DC microgrid system to provide auxiliary power for lighting, control and communication in a DC light rail vehicle. Three converters with low voltage and current stresses of power devices are series-connected with single transformers to convert a high voltage input to a low voltage output for a DC light rail vehicle. Thus, Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with a low voltage rating and a turn-on resistance are adopted in the proposed circuit topology in order to decrease power losses on power switches and copper losses on transformer windings. A duty cycle control with an asymmetric pulse-width modulation is adopted to control the output voltage at the desired voltage level. It is also adopted to reduce switching losses on MOSFETs due to the resonant behavior from a leakage inductor of an isolated transformer and output capacitor of MOSFETs at the turn-on instant. The feasibility and effectiveness of the proposed circuit have been verified by a laboratory prototype with a 760 V input and a 24 V/60 A output.

Section: Introductionmentioning

confidence: 99%

Series-Connected High Frequency Converters in a DC Microgrid System for DC Light Rail Transit

2018

Energies

“…Power converters with soft-switching turn-on or turn-off characteristics have been proposed and studied to overcome these problems. Duty cycle control [8][9][10][11][12][13] and frequency control schemes [14][15][16] are normally used to regulate load voltage and also reduce switching losses under zero-voltage or zero-current. The advantages of duty cycle control with fixed switching frequency are easy implementation with commercial integrated circuits and many available circuit topologies.…”

Section: Introductionmentioning

confidence: 99%

Frequency-Controlled Current-Fed Resonant Converter with No Input Ripple Current

2018

Energies

This paper studies a frequency-controlled current-fed resonant circuit. The adopted direct current (DC)-to-DC converter contains two boost circuits and a resonant circuit on the primary side. First, two boost circuits are connected in parallel to achieve voltage step-up and reduce input ripple current by using interleaved pulse-width modulation. Therefore, the size and current rating of boost inductors are decreased in the proposed converter. Second, the boost voltage is connected to the resonant circuit to realize the mechanism of the zero-voltage switching of all active switches and zero-current switching of all diodes. Two boost circuits and a resonant circuit use the same power devices in order to lessen the switch counts. The voltage doubler topology is adopted on the secondary side (high-voltage side). Therefore, the voltage rating of diodes on the high-voltage side is clamped at output voltage. The feasibility of the studied circuit is confirmed by the experimental tests with a 1 kW prototype circuit.

“…Half-bridge topology and full-bridge topology are mostly used in the second stage of AC/DC converters for medium power applications to provide the stable DC output voltage. To achieve high circuit efficiency, light weight and a compact size, power converters with soft-switching techniques [1][2][3][4][5][6][7][8][9][10][11][12][13] have been developed for more than 20 years. Active clamped circuits [1,2], asymmetric pulse-width modulation (APWM) [3][4][5][6][7][8], resonant converters [9,10] and phase-shift PWM [11][12][13] have been developed to achieve zero-voltage switching (ZVS) turn-on for power switches.…”

Section: Introductionmentioning

confidence: 99%

“…To achieve high circuit efficiency, light weight and a compact size, power converters with soft‐switching techniques [1–13] have been developed for more than 20 years. Active clamped circuits [1, 2], asymmetric pulse‐width modulation (APWM) [3–8], resonant converters [9, 10] and phase‐shift PWM [11–13] have been developed to achieve zero‐voltage switching (ZVS) turn‐on for power switches. The active‐clamping topology is one kind of soft‐switching technique to achieve ZVS turn‐on by utilising the energy stored in the leakage and magnetising inductances.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Parallel asymmetric pulse‐width modulation converters with same power switches for medium power applications

Chen

2014

IET Power Electronics

A new zero-voltage switching (ZVS) half-bridge converter with three circuit modules is presented in this study to reduce the switching losses of power switches and current stress of passive components for medium power applications. Three circuit modules with the same power switches are connected in parallel at input and output sides. Thus, the switch counts are reduced compared with the parallel half-bridge converter with the same power rating. Each circuit module supplies one-third of load power to output side. Owing to the half-bridge converter leg, the voltage stress of each power switch is clamped at input DC voltage. Three centre-tapped rectifiers are adopted at low voltage side to share load current and reduce the size of magnetic cores. Asymmetric pulse-width modulation is adopted to regulate output voltage at the desired voltage level. Owing to the resonant behaviour by resonant capacitance [or output capacitance of metal-oxide semiconductor fieldeffect transistors (MOSFETs)] and leakage inductance (or external inductance) at the transition interval, power MOSFETs can be turned on under ZVS. The system analysis, circuit characteristics and design example of the proposed converter are discussed in detail. Finally, experiments with a 1620 W prototype are provided to verify the effectiveness of the proposed converter.