EPE Association: EPE 2011 - LS8d: Topic 04: Soft Switching Converters

EPE 2011 - LS8d: Topic 04: Soft Switching Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 04: Soft Switching Converters and Control > EPE 2011 - LS8d: Topic 04: Soft Switching Converters

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   Dual Active Bridge Modulation with Complete Zero Voltage Switching Taking Resonant Transitions into Account
By Giuseppe GUIDI, Atsuo KAWAMURA, Yuji SASAKI, Tomofumi IMAKUBO [View]
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Abstract: The paper proposes an optimized modulation scheme for the Dual Active Bridge (DAB) converter topology, ensuring complete Zero Voltage Switching (ZVS) over the whole operating range. At first, ZVS limits for the modulation scheme in use are evaluated, taking the effect of resonant commutations into account. A strategy to achieve ZVS over the whole operating area is then proposed. A simple procedure to analytically calculate the switching pattern is presented, achieving high conversion efficiency without using complex loss models. Performance of the proposed control system is evaluated by actual measurements on a 2 kW DAB prototype, showing that complete ZVS is obtained over the whole operating range of the converter, resulting in high conversion efficiency even in the case of light load and buck/boost ratio considerably different from unity.

   Efficiency Comparison between Motor Friendly Hard and Soft Switching Inverters
By Jayalakshmi KEDARISETTI, Peter MUTSCHLER [View]
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Abstract: This paper compares two motor-friendly inverters. One is quasi resonant DC-link soft switching inverter and the other one is hard switching inverter together with a filter. The soft switching inverter is designed for reduced dv/dt. With the use of an additional switch, peak common mode voltage is also reduced. In order to evaluate the motor-friendly characteristic of a soft switching inverter, the experimental results regarding the line to line voltage, line to earth voltage and common mode voltage effects on motor fed with long cable are presented. Furthermore, important comparisons with hard switching operation of the same inverter (resonant circuit not operated) with commercially available filters connected at inverter output, regarding the effects and efficiency are presented. Conclusions are then drawn that motor-friendly SS inverter is an alternative to HS inverter with a sine-wave EMC output filter. The motor-friendly soft switching inverter does not need an output filter. So it has good dynamics compare to a hard switching inverter with a sine-wave EMC output filter.

   ZVS Three-Level Phase-Shift High Step-Down DC/DC Converter with Two Transformers
By Peng LI, Wuhua LI, Xiangning HE [View]
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Abstract: A novel three-level phase-shift DC/DC converter with two series-connected transformers is proposed in this paper to meet the requirements for high step-down ratio and high input voltage applications. The three-level construction internally halves the voltage stress of the power switch compared with the traditional full-bridge topology, for which the low-voltage-rated MOSFETs are used to reduce the conduction losses. Also, the inclusion of the flying capacitor allows the phase-shift operation of this converter to achieve ZVS for all the primary power switches to improve the efficiency. Since the flying capacitor is in parallel with each of the input capacitor during the different operational modes of one switching cycle, the voltage imbalance of the input capacitors can be reduced. The two transformers in series both work as an inductor and a transformer alternately during different intervals of the period. As a result, not only the ZVS range of the lagging leg is extended but also the output inductor is omitted. The voltage-conversion-ratio is quartered by both the three-level structure and the two staggered transformers, which is suitable for high step down situations. The operational principles are presented in this paper. Besides, the state space functions and the design equations of the proposed converter are also derived. Finally a 240W/500V-24V prototype is built and tested to verify the effectiveness of this converter.

EPE 2011 - LS8d: Topic 04: Soft Switching Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 04: Soft Switching Converters and Control > EPE 2011 - LS8d: Topic 04: Soft Switching Converters
	[return to parent folder]

	Dual Active Bridge Modulation with Complete Zero Voltage Switching Taking Resonant Transitions into Account By Giuseppe GUIDI, Atsuo KAWAMURA, Yuji SASAKI, Tomofumi IMAKUBO	[View] [Download]
Abstract: The paper proposes an optimized modulation scheme for the Dual Active Bridge (DAB) converter topology, ensuring complete Zero Voltage Switching (ZVS) over the whole operating range. At first, ZVS limits for the modulation scheme in use are evaluated, taking the effect of resonant commutations into account. A strategy to achieve ZVS over the whole operating area is then proposed. A simple procedure to analytically calculate the switching pattern is presented, achieving high conversion efficiency without using complex loss models. Performance of the proposed control system is evaluated by actual measurements on a 2 kW DAB prototype, showing that complete ZVS is obtained over the whole operating range of the converter, resulting in high conversion efficiency even in the case of light load and buck/boost ratio considerably different from unity.

	Efficiency Comparison between Motor Friendly Hard and Soft Switching Inverters By Jayalakshmi KEDARISETTI, Peter MUTSCHLER	[View] [Download]
Abstract: This paper compares two motor-friendly inverters. One is quasi resonant DC-link soft switching inverter and the other one is hard switching inverter together with a filter. The soft switching inverter is designed for reduced dv/dt. With the use of an additional switch, peak common mode voltage is also reduced. In order to evaluate the motor-friendly characteristic of a soft switching inverter, the experimental results regarding the line to line voltage, line to earth voltage and common mode voltage effects on motor fed with long cable are presented. Furthermore, important comparisons with hard switching operation of the same inverter (resonant circuit not operated) with commercially available filters connected at inverter output, regarding the effects and efficiency are presented. Conclusions are then drawn that motor-friendly SS inverter is an alternative to HS inverter with a sine-wave EMC output filter. The motor-friendly soft switching inverter does not need an output filter. So it has good dynamics compare to a hard switching inverter with a sine-wave EMC output filter.

	ZVS Three-Level Phase-Shift High Step-Down DC/DC Converter with Two Transformers By Peng LI, Wuhua LI, Xiangning HE	[View] [Download]
Abstract: A novel three-level phase-shift DC/DC converter with two series-connected transformers is proposed in this paper to meet the requirements for high step-down ratio and high input voltage applications. The three-level construction internally halves the voltage stress of the power switch compared with the traditional full-bridge topology, for which the low-voltage-rated MOSFETs are used to reduce the conduction losses. Also, the inclusion of the flying capacitor allows the phase-shift operation of this converter to achieve ZVS for all the primary power switches to improve the efficiency. Since the flying capacitor is in parallel with each of the input capacitor during the different operational modes of one switching cycle, the voltage imbalance of the input capacitors can be reduced. The two transformers in series both work as an inductor and a transformer alternately during different intervals of the period. As a result, not only the ZVS range of the lagging leg is extended but also the output inductor is omitted. The voltage-conversion-ratio is quartered by both the three-level structure and the two staggered transformers, which is suitable for high step down situations. The operational principles are presented in this paper. Besides, the state space functions and the design equations of the proposed converter are also derived. Finally a 240W/500V-24V prototype is built and tested to verify the effectiveness of this converter.