Analysis and implementation of a new zero‐voltage switching DC converter with less active switches

Self Cite

A DC/DC converter with parallel input and parallel output circuit topology is presented to achieve the main features of reduced switch count and medium power level compared with conventional parallel half-bridge resonant converter. The proposed converter has three resonant circuits to share load currents and reduce the current stress of circuit components. These three resonant circuits use the same power switches to deliver power from input side to output load so that the switch counts are reduced compared with the conventional parallel resonant converter. The rectifier diodes at the secondary side of three resonant circuits are partially used in common so that the diode counts are also reduced. Since three resonant circuits are connected in parallel, the sizes of the transformers and active and passive components are reduced. The switching frequency of the proposed converter is operated to be less than the series resonant frequency. Thus, active switches are turned on under zero voltage switching and rectifier diodes are turned off under zero current switching. A 1.6 kW laboratory prototype is designed and constructed to demonstrate the feasibility and performance of the proposed circuit.

Section: Introductionmentioning

confidence: 99%

DC/DC converter with parallel input and parallel output with shared power switches and rectifier diodes

Lin

Chu

2015

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“…However, power switches in conventional multilevel converters are operated at hard switching. In [11][12][13][14][15], three-level converters with soft switching scheme were developed to reduce the switching losses on power switches. Normally, the output capacitor of power switches and the leakage inductance of transformer are resonant at the transition interval to achieve zero-voltage switching (ZVS) on power switches.…”

Section: Introductionmentioning

confidence: 99%

Interleaved resonant converter with the balanced flying capacitors

Lin¹,

Chen²

2015

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This study presents a new DC/DC converter for high input voltage and high load current applications. To adopt low voltage rating power devices in high voltage applications, two split capacitors with four active switches are used in the primary side to reduce the voltage stress of power switches at V in /2. Two flying capacitances are used to automatically balance two split capacitor voltages in every switching cycle. The proposed converter includes two resonant circuits to share the load current and to reduce the current stress of passive components. If the switching frequency is less than the series resonant frequency, power switches can be turned on under zero-voltage switching and rectifier diodes can be turned off under zero current switching. Therefore the switching losses on power semiconductors are reduced. The interleaved pulse-width modulation is adopted to further reduce the ripple current at output side. Thus, the output filter inductances can be reduced. Finally, experiments with a 1.2 kW prototype are provided to verify the effectiveness of the proposed converter.

“…High-frequency link DC/DC converters based on three-level pulse-width modulation scheme have been proposed and developed in [1,2] to reduce the voltage stress of switches at half of input voltage for industry power supply units. To eliminate the switching noise and electromagnetic interference caused by hard switching, soft switching three-level DC/DC converters have been presented in [3][4][5]. Thus, the switching losses of switches are reduced and the electromagnetic interference is also improved.…”

Section: Introductionmentioning

confidence: 99%

Soft switching DC/DC converter with five resonant tanks for medium voltage applications

Lin¹,

Chen²

2015

Self Cite

A zero-voltage switching (ZVS) converter with five resonant circuits with shared switches is presented to achieve the functions of less switch counts, low switching losses and low current stress of passive components at low-voltage side. For medium input voltage case, four split capacitors and four active switches with V in /2 voltage stress are adopted at highvoltage side. Two balance capacitors are used to automatically balance input capacitor voltages in every switching cycle. Five resonant circuits are adopted in the proposed converter to share load current and reduce the current stress of passive components. On the basis of the circuit characteristics of resonant converter, power switches are turned on at ZVS from zero to full load. Rectifier diodes can be turned off at zero-current switching if the switching frequency is less than the series resonant frequency. Hence, the reverse recovery losses on the rectifier diodes are improved. Experimental verifications with a 1.92 kW prototype are provided to demonstrate the effectiveness of the proposed converter.