Three-level zero-voltage switching pulse-width modulation DC–DC boost converter with active clamping

-A novel parallel three-level zero voltage switching (ZVS) DC converter is presented for medium voltage applications. The proposed converter includes three sub-circuits connected in parallel with the same power switches to share load current and reduce the current stress of passive components at the output side. Thus, the size of the output chokes is reduced and the switch counts in the proposed converter are less that in the conventional parallel three-level DC/DC converter. Each sub-circuit combines one half-bridge converter and one three-level converter. The transformer secondary windings of these two converters are connected in series in order to reduce the size of output inductor. Due to the three-level circuit topology, the voltage stress of power switches is equal to V in /2. Based on the resonant behavior by the output capacitance of power switches and the leakage inductance (or external inductance) at the transition interval, each switch can be turned on under ZVS. Finally, experiments based on a 2 kW prototype are provided to verify the performance of the proposed converter.

“…(1) Diodes D 1 -D 6 and clamped diodes D a -D b are ideal, (2) MOSFETs S 1 -S 4 are ideal except for the internal anti-parallel diode of it and the output capacitors…”

Section: Operation Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of a New Parallel Three-Level Zero-Voltage Switching DC Converter

Lin¹,

Chen²

2015

“…In [1] and [10], flying capacitor is adopted to the conventional three-level neutral point clamped converter to automatically balance two input capacitor voltages. Three-level zero voltage switching (ZVS) converters [11][12][13][14][15][16][17] have been presented to reduce the switching losses and increase the circuit efficiency. Pulse-width modulation (PWM) schemes are adopted to generate the PWM signals for active switches and to regulate output voltage.…”

Section: Introductionmentioning

confidence: 99%

Analysis of an Interleaved Resonant Converter for High Voltage and High Current Applications

Lin¹,

Chen²

2014

-This paper presents an interleaved resonant converter to reduce the voltage stress of power MOSFETs and achieve high circuit efficiency. Two half-bridge converters are connected in series at high voltage side to limit MOSFETs at V in /2 voltage stress. Flying capacitor is used between two series half-bridge converters to balance two input capacitor voltages in each switching cycle. Variable switching frequency scheme is used to control the output voltage. The resonant circuit is operated at the inductive load. Thus, the input current of the resonant circuit is lagging to the fundamental input voltage. Power MOSFETs can be turn on under zero voltage switching. Two resonant circuits are connected in parallel to reduce the current stress of transformer windings and rectifier diodes at low voltage side. Interleaved pulse-width modulation is adopted to decrease the output ripple current. Finally, experiments are presented to demonstrate the performance of the proposed converter.

“…In order to increase the circuit efficiency and reduce the power losses, soft switching techniques [7][8][9][10][11][12][13][14][15] such as active clamp technique, asymmetric pulse-width modulation (PWM) scheme and series resonant technique have been proposed and used in the two-level PWM converters. For medium power and high input voltage applications, three-level zero voltage switching (ZVS) converters [16][17][18][19] have been proposed to have the features of low voltage stress of power semiconductors and high circuit efficiency. In these techniques, the leakage inductance of the transformer (or external inductance) and the output capacitance of power switches are resonant at the transition interval.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Implementation of a New ZVS DC Converter for Medium Power Application

Lin¹,

Shiau²

2014

-This paper presents a new zero voltage switching (ZVS) converter for medium power and high input voltage applications. Three three-level pulse-width modulation (PWM) circuits with the same power switches are adopted to clamp the voltage stress of MOSFETs at V in /2 and to achieve load current sharing. Thus, the current stresses and power ratings of transformers and power semiconductors at the secondary side are reduced. The resonant inductance and resonant capacitance are resonant at the transition interval such that active switches are turned on at ZVS within a wide range of input voltage and load condition. The series-connected transformers are adopted in each threelevel circuit. Each transformer can work as an inductor to smooth the output current or a transformer to achieve the electric isolation and power transfer. Thus, no output inductor is needed at the secondary side. Three center-tapped rectifiers connected in parallel are used at the secondary side to achieve load current sharing. Compared with the conventional parallel three-level converters, the proposed converter has less switch counts. Finally, experiments based on a 1.44kW prototype are provided to verify the operation principle of proposed converter.