2011 24th Canadian Conference on Electrical and Computer Engineering(CCECE), 2011
... [3] E. Adib and H. Farzanehfard, Family of Soft-Switching PWM Converters With Current Sharin... more ... [3] E. Adib and H. Farzanehfard, Family of Soft-Switching PWM Converters With Current Sharing in Switches, IEEE Transactions On Power Electronics, Vol. 24, No. 4, April 2009. [4] E. Adib and H. Farzanehfard, Family of ZCZVT PWM converters, IET Power Electronics, Vol. ...
In the buck-derived, push-pull and bridge-type topologies. the output inductor current during swi... more In the buck-derived, push-pull and bridge-type topologies. the output inductor current during switch-off interval can freewheel either through the shorted secondaries of the transformer or through a separate freewheeling diode. It is shown that the former method results in highly nonlinear DC voltage-conversion-ratio characteristics for zerocurrent-switched quasi-resonant converters operating in half-wave mode. As a result, the incremental gain of the power stage of these converters vary in an extremely wide range with input voltage and load. Consequently, it is not possible to achieve a stable feedback control with high-loop gains using conventional compensation techniques. The addition of a freewheeling diode not only linearizes the DC characteristics but also results in a reduction of current and voltage stresses on semiconductor devices and an improved efficiency.
A performance comparison of flyback, forward, and halfbridge zero-current-switched quasi-resonant... more A performance comparison of flyback, forward, and halfbridge zero-current-switched quasi-resonant converter topologies for high-frequency off-line applications is presented. It is shown that the balf-bridge topology with secondary-side resonance operating in balfwave mode is most suitable. A complete design procedure for the halfbridge power stage and the voltage-feedback control is presented together with experimental results for a 300-V dc hybridized converter which operates with conversion frequencies from 400 kHz to 2 MHz and delivers 1.5-16 A at 5 V dc.
Page 1. 62 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. PE-2, NO. 1, JANUARY 1987 Quasi-Resonant ... more Page 1. 62 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. PE-2, NO. 1, JANUARY 1987 Quasi-Resonant Converters Topologies and Characteristics KWANG-HWA LIU, RAMESH ORUGANTI, AND FRED CY LEE, MEMBER, IEEE ...
Thick-film hybrid technology is used to develop a halfbridge, half-wave, zero-current-switched qu... more Thick-film hybrid technology is used to develop a halfbridge, half-wave, zero-current-switched quasi-resonant converter for 300-V dc off-line application. With a conversion frequency of 2 MHz the converter delivers 80 W at 78-percent efficiency with a power density, excluding heat sink, of 21 W/in3. The operation and detailed electrical and hybrid design of the circuit are described. Also described is a 2-MHz hybridized gate drive.
Operative Techniques in Otolaryngology-head and Neck Surgery, 1996
A nonlinear modeling approach for zero-current-switch (ZCS) quasi-resonant converters (QRC) is pr... more A nonlinear modeling approach for zero-current-switch (ZCS) quasi-resonant converters (QRC) is proposed which can be derived easily using simple analytical techniques. The converter model obtained is readily absorbed by MATLAB for analysis and design of both the open- and closed-loop configurations in fast speed. Simulations have shown its accuracy, even for large-signal transient responses. Applications of this modeling approach to
In this paper a zero current switching resonant Buck converter as a soft-switching DC-DC converte... more In this paper a zero current switching resonant Buck converter as a soft-switching DC-DC converter is presented In this buck type converter, all semiconductor elements are soft switched. Also, the converter benefits from a very simple control method. Theoretical equations are derived and confirmed through simulation results. Finally, the results from the realized converter prototype are presented which confirm the theoretical analysis.
An equivalently derived circuit model (EDM) with the transformer T-model incorporated for general... more An equivalently derived circuit model (EDM) with the transformer T-model incorporated for generalizing and simplifying the design of zero-current-switched forward resonant power converters (forward ZCS-RC) is proposed. The modeling for the three kinds of converters, ZCS parallel-resonant-converters, ZCS quasi-resonant-converters, and ZCS primary-secondary-resonant-converters, is conducted by the state-variable approach. Using the presented EDM, the three kinds of resonant converters are analyzed in the discontinuous conduction mode. Compensator design for stabilizing the system performance is described. To verify the modeling results, a typical design example is presented and its simulated results are compared with the measured data
Generalized topologies of zero-voltage-switching and zero-current-switching resonant dc/dc power ... more Generalized topologies of zero-voltage-switching and zero-current-switching resonant dc/dc power converters are presented. It is shown that many equivalent topologies of the converters can be derived from each of the generalized topologies. Furthermore, the generalized topologies of the converters show clearly which of the parasitic capacitances and inductances can be absorbed into the LC resonant circuit. This allows the designer to choose the most suitable topology of a given converter for high-frequency operation.
In materials processing, the power density control of a laser beam has been considered to be sign... more In materials processing, the power density control of a laser beam has been considered to be significant. In this study, a zero-current switching resonant converter as the power supply of a pulsed Nd:YAG laser was adopted to control the laser power density, which depends on flashlamp current pulsewidth and pulse repetition rate. It allowed us to design and fabricate a high repetition rate and high power pulsed Nd:YAG laser system. As a result of that, the current pulsewidth could be controlled in the range 200–350 μs (step 50 μs), and the pulse repetition rate could be adjusted to 500–1150 pps (pulse per second). In addition, in the case of one laser head consisting of an Nd:YAG laser rod and two flashlamps, the maximum laser output of 240 W was produced at the condition of 350 μs and 1150 pps, and that of about 480 W was generated at the same condition when two laser heads were arranged in cascade.
The problems associated with IGT/COMFET devices in PWM converters, such as turn-off current taili... more The problems associated with IGT/COMFET devices in PWM converters, such as turn-off current tailing and turn-off latching, are largely avoided in a zero-current switching resonant converter. dv/dt induced phenomena, such as the power losses and latching, are identified as the predominant problems in using IGT/COMFET devices for very-high-frequency resonant operation.
For a zero-current switching series-resonant inverter, the authors show that it is possible to re... more For a zero-current switching series-resonant inverter, the authors show that it is possible to reduce the order of the model by one, which becomes linear in addition. The synthesis of a control law is thereby facilitated, and current-mode control appears to be the most attractive. Simulation results have confirmed the above statements
A soft-switching converter with dual resonant structures is presented in this article. The dual r... more A soft-switching converter with dual resonant structures is presented in this article. The dual resonant tanks are composed of the leakage inductors and resonant capacitors to achieve a zero-current-switching (ZCS) turn-off mechanism for diodes on the secondary side of the transformer. Moreover, the voltage stresses of power switches are clamped by the active clamp circuit on the primary side of the transformer. The active clamp circuit has not only absorbed the energy stored in the leakage inductor but also creates a zero-voltage-switching turn-on feature for power switches. Hence, the reverse-recovery problem can be eliminated. The operational principles, design considerations and realisation are discussed. Finally, the experimental results from a 400 W prototype are presented to confirm the effectiveness of the proposed converter.
The authors present a novel half-bridge pulse-width modulated zero-current-switched quasi-resonan... more The authors present a novel half-bridge pulse-width modulated zero-current-switched quasi-resonant converter for offline application, derived from the half-bridge frequency-modulated zero-current-switched quasi-resonant converter with secondary-side resonance and a separate freewheeling diode. It is shown that the proposed converter operates under constant frequency and is regulated by pulse-width modulation, with lossless commutation. A detailed analysis, the design procedure, simulation, and experimental results are presented. A laboratory prototype rated at 140 W, operating at a switching frequency of 500 kHz and resonant frequency of 2.5 MHz, has been implemented and tested
A new family of zero-current-transition (ZCT) pulsewidth-modulated (PWM) converters is proposed. ... more A new family of zero-current-transition (ZCT) pulsewidth-modulated (PWM) converters is proposed. The new family of converters implements zero-current turn-off for power transistor(s) without increasing voltagdcurrent stresses and operates at a fixed frequency. The proposed converters are deemed most suitable for high-power applications where the minority-carrier semiconductor devices (such as IGBT's, BJT's, and MCT's) are predominantly used as the power switches. Theoretical analysis is verified on a 100 kHz, 1 kW ZCT-PWM boost converter using an IGBT.
2011 24th Canadian Conference on Electrical and Computer Engineering(CCECE), 2011
... [3] E. Adib and H. Farzanehfard, Family of Soft-Switching PWM Converters With Current Sharin... more ... [3] E. Adib and H. Farzanehfard, Family of Soft-Switching PWM Converters With Current Sharing in Switches, IEEE Transactions On Power Electronics, Vol. 24, No. 4, April 2009. [4] E. Adib and H. Farzanehfard, Family of ZCZVT PWM converters, IET Power Electronics, Vol. ...
In the buck-derived, push-pull and bridge-type topologies. the output inductor current during swi... more In the buck-derived, push-pull and bridge-type topologies. the output inductor current during switch-off interval can freewheel either through the shorted secondaries of the transformer or through a separate freewheeling diode. It is shown that the former method results in highly nonlinear DC voltage-conversion-ratio characteristics for zerocurrent-switched quasi-resonant converters operating in half-wave mode. As a result, the incremental gain of the power stage of these converters vary in an extremely wide range with input voltage and load. Consequently, it is not possible to achieve a stable feedback control with high-loop gains using conventional compensation techniques. The addition of a freewheeling diode not only linearizes the DC characteristics but also results in a reduction of current and voltage stresses on semiconductor devices and an improved efficiency.
A performance comparison of flyback, forward, and halfbridge zero-current-switched quasi-resonant... more A performance comparison of flyback, forward, and halfbridge zero-current-switched quasi-resonant converter topologies for high-frequency off-line applications is presented. It is shown that the balf-bridge topology with secondary-side resonance operating in balfwave mode is most suitable. A complete design procedure for the halfbridge power stage and the voltage-feedback control is presented together with experimental results for a 300-V dc hybridized converter which operates with conversion frequencies from 400 kHz to 2 MHz and delivers 1.5-16 A at 5 V dc.
Page 1. 62 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. PE-2, NO. 1, JANUARY 1987 Quasi-Resonant ... more Page 1. 62 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. PE-2, NO. 1, JANUARY 1987 Quasi-Resonant Converters Topologies and Characteristics KWANG-HWA LIU, RAMESH ORUGANTI, AND FRED CY LEE, MEMBER, IEEE ...
Thick-film hybrid technology is used to develop a halfbridge, half-wave, zero-current-switched qu... more Thick-film hybrid technology is used to develop a halfbridge, half-wave, zero-current-switched quasi-resonant converter for 300-V dc off-line application. With a conversion frequency of 2 MHz the converter delivers 80 W at 78-percent efficiency with a power density, excluding heat sink, of 21 W/in3. The operation and detailed electrical and hybrid design of the circuit are described. Also described is a 2-MHz hybridized gate drive.
Operative Techniques in Otolaryngology-head and Neck Surgery, 1996
A nonlinear modeling approach for zero-current-switch (ZCS) quasi-resonant converters (QRC) is pr... more A nonlinear modeling approach for zero-current-switch (ZCS) quasi-resonant converters (QRC) is proposed which can be derived easily using simple analytical techniques. The converter model obtained is readily absorbed by MATLAB for analysis and design of both the open- and closed-loop configurations in fast speed. Simulations have shown its accuracy, even for large-signal transient responses. Applications of this modeling approach to
In this paper a zero current switching resonant Buck converter as a soft-switching DC-DC converte... more In this paper a zero current switching resonant Buck converter as a soft-switching DC-DC converter is presented In this buck type converter, all semiconductor elements are soft switched. Also, the converter benefits from a very simple control method. Theoretical equations are derived and confirmed through simulation results. Finally, the results from the realized converter prototype are presented which confirm the theoretical analysis.
An equivalently derived circuit model (EDM) with the transformer T-model incorporated for general... more An equivalently derived circuit model (EDM) with the transformer T-model incorporated for generalizing and simplifying the design of zero-current-switched forward resonant power converters (forward ZCS-RC) is proposed. The modeling for the three kinds of converters, ZCS parallel-resonant-converters, ZCS quasi-resonant-converters, and ZCS primary-secondary-resonant-converters, is conducted by the state-variable approach. Using the presented EDM, the three kinds of resonant converters are analyzed in the discontinuous conduction mode. Compensator design for stabilizing the system performance is described. To verify the modeling results, a typical design example is presented and its simulated results are compared with the measured data
Generalized topologies of zero-voltage-switching and zero-current-switching resonant dc/dc power ... more Generalized topologies of zero-voltage-switching and zero-current-switching resonant dc/dc power converters are presented. It is shown that many equivalent topologies of the converters can be derived from each of the generalized topologies. Furthermore, the generalized topologies of the converters show clearly which of the parasitic capacitances and inductances can be absorbed into the LC resonant circuit. This allows the designer to choose the most suitable topology of a given converter for high-frequency operation.
In materials processing, the power density control of a laser beam has been considered to be sign... more In materials processing, the power density control of a laser beam has been considered to be significant. In this study, a zero-current switching resonant converter as the power supply of a pulsed Nd:YAG laser was adopted to control the laser power density, which depends on flashlamp current pulsewidth and pulse repetition rate. It allowed us to design and fabricate a high repetition rate and high power pulsed Nd:YAG laser system. As a result of that, the current pulsewidth could be controlled in the range 200–350 μs (step 50 μs), and the pulse repetition rate could be adjusted to 500–1150 pps (pulse per second). In addition, in the case of one laser head consisting of an Nd:YAG laser rod and two flashlamps, the maximum laser output of 240 W was produced at the condition of 350 μs and 1150 pps, and that of about 480 W was generated at the same condition when two laser heads were arranged in cascade.
The problems associated with IGT/COMFET devices in PWM converters, such as turn-off current taili... more The problems associated with IGT/COMFET devices in PWM converters, such as turn-off current tailing and turn-off latching, are largely avoided in a zero-current switching resonant converter. dv/dt induced phenomena, such as the power losses and latching, are identified as the predominant problems in using IGT/COMFET devices for very-high-frequency resonant operation.
For a zero-current switching series-resonant inverter, the authors show that it is possible to re... more For a zero-current switching series-resonant inverter, the authors show that it is possible to reduce the order of the model by one, which becomes linear in addition. The synthesis of a control law is thereby facilitated, and current-mode control appears to be the most attractive. Simulation results have confirmed the above statements
A soft-switching converter with dual resonant structures is presented in this article. The dual r... more A soft-switching converter with dual resonant structures is presented in this article. The dual resonant tanks are composed of the leakage inductors and resonant capacitors to achieve a zero-current-switching (ZCS) turn-off mechanism for diodes on the secondary side of the transformer. Moreover, the voltage stresses of power switches are clamped by the active clamp circuit on the primary side of the transformer. The active clamp circuit has not only absorbed the energy stored in the leakage inductor but also creates a zero-voltage-switching turn-on feature for power switches. Hence, the reverse-recovery problem can be eliminated. The operational principles, design considerations and realisation are discussed. Finally, the experimental results from a 400 W prototype are presented to confirm the effectiveness of the proposed converter.
The authors present a novel half-bridge pulse-width modulated zero-current-switched quasi-resonan... more The authors present a novel half-bridge pulse-width modulated zero-current-switched quasi-resonant converter for offline application, derived from the half-bridge frequency-modulated zero-current-switched quasi-resonant converter with secondary-side resonance and a separate freewheeling diode. It is shown that the proposed converter operates under constant frequency and is regulated by pulse-width modulation, with lossless commutation. A detailed analysis, the design procedure, simulation, and experimental results are presented. A laboratory prototype rated at 140 W, operating at a switching frequency of 500 kHz and resonant frequency of 2.5 MHz, has been implemented and tested
A new family of zero-current-transition (ZCT) pulsewidth-modulated (PWM) converters is proposed. ... more A new family of zero-current-transition (ZCT) pulsewidth-modulated (PWM) converters is proposed. The new family of converters implements zero-current turn-off for power transistor(s) without increasing voltagdcurrent stresses and operates at a fixed frequency. The proposed converters are deemed most suitable for high-power applications where the minority-carrier semiconductor devices (such as IGBT's, BJT's, and MCT's) are predominantly used as the power switches. Theoretical analysis is verified on a 100 kHz, 1 kW ZCT-PWM boost converter using an IGBT.
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