EPE Association: EPE 2017 - DS1k: Power Supplies

EPE 2017 - DS1k: Power Supplies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 07: Power Supplies > EPE 2017 - DS1k: Power Supplies

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   A Novel Generation Method of Gate Signals for Synchronous Rectification Operation in LLC Resonant Converters
By Kyungmin SUNG [View]
[Download]

Abstract: This paper proposes the novel generation method of gate signals to control output voltage in a wide range and to achieve synchronous rectification operating in half-bridge LLC resonant converters. The switching frequency modulation is used in half-bridge LLC resonant converters for control strategy of output voltage. The switching timing of secondary MOSFETs is compensated using the gate signal of primary side by the reference value of switching frequency without any detection circuits. The Current Doubler Synchronous Rectifier (CDSR) and the Center Tapped Synchronous Rectifier (CTSR) are implemented for secondary circuit in the experiment. According to experimental results, not only stable operation in a wide switching frequency range but also the improved conversion efficiency is achieved by the proposed method.

   A Very Low THD and High Power Factor Primary Side Regulation LED Driver
By Giovanni GRITTI [View]
[Download]

Abstract: This paper introduces a new power factor correction scheme for a Flyback converter with primary regulation technique, to ideally eliminate the distortion of the ac input current (practically a Total Harmonic Distortion (THD) lower than 5\%). The effectiveness of the new control scheme is proved in a 35W driver with universal input range (90VAC~277VAC). Application target is Solid State Lighting (LED drivers).

   Adjustable Speed Generation System Under Fault Condition
By WLODZIMIERZ KOCZARA [View]
[Download]

Abstract: Paper presents performance of the 40kVA autonomous, adjustable speed generation system in a short circuit condition, protected by a B-class tripping switch. Tripping switch is unable to clear the short-circuit event when an inverter current is limited, thus a topology of asynchronous bypass is developed, which delivers additional current directly from permanent magnet generator. Experiments of the laboratory stand that has been carried out, including asynchronous bypass, concludes that the sum of the inverter current and permanent magnet current results in disconnection of the affected load in time less than 20 ms.

   Buck Mode Control Methods of the qZS-Resonant DC/DC Converters
By Ivars RANKIS [View]
[Download]

Abstract: The series resonant DC/DC converter with an isolation transformer and bridge mode inverter input junction, at its operation in the Buck case, is investigated, at that input DC supply circuit comprises the qZ (quasi-Z) link as impedance source. Operation at such Buck case can be provided under different inverter bridge control methods. Recommended by the literature sources, is the method of control with rising of switching frequency above the resonant one. Two compromise methods here are proposed too - with phase shift of the bridge legs switching, and the asymmetric control method, when switching pattern of the bridge's switches is asymmetrical in time. Simplified descriptions of processes in the system for before mentioned control principles are presented, as well expressions for approximate calculation of the main parameters of the system at the methods are derived too. Influence of q-Z link properties on restrictions of resonant processes is described. Computer simulations of the operation cases, approving sufficient correctness of the simplifications accepted at analyses, are provided. Comparison of results regarding to the applied control methods, as well some recommendations about application of the systems, is done.

   Contactless Power Transfer in Seawater
By MAMIKO INAMORI [View]
[Download]

Abstract: This paper investigates the fundamental characteristics of contactless power transfer in seawater. The influence of seawater on contactless power transfer via magnetic resonant coupling method is experi- mentally examined. The experimental results show that the transmission efficiency decreases about 5\% in seawater compared to that of in air.

   Current-Source PFC based LED Drivers with Electronic-Smoothing Inductor for AC Power Decoupling
By Chi Shing WONG [View]
[Download]

Abstract: The paper proposes an electronic-smoothing inductor (ESI) as an energy storage element in current-sourcePFC based LED drivers. In comparison with the passive inductor approach, the required inductancevalue of the overall driver circuit can be significantly reduced such that better power density andefficiency can be achieved. The derivation of different structures of current-source LED drivers by dualityprinciple is also discussed in this paper. The idea is validated by a single-stage, current-boost PFCpre-regulator for low-power LED lighting applications.

   Design of a bi-directional full bridge LLC resonant converter with a higher normalized voltage gain under backward mode
By Junping HE [View]
[Download]

Abstract: A step-up control method is proposed to solve the problem of the normalized voltage gain less than 1 when the bi-directional LLC resonant converter works in backward mode. This step-up control method turns on rectifier switches to help resonant components recover their energy and improves the normalized voltage gain to 2. Working principle of the bidirectional LLC resonant converter is introduced firstly. The working procedures under continuous mode and discontinuous mode are analyzed and deduced in detail too. In the end, a 3kW prototype is built up for UPS battery charger application. The MATLAB simulation and experiment results show that this proposed bidirectional LLC resonant circuit works with a high efficiency and the normalized voltage gain can be greater than 1 in the backward operation. Certainly, most of the switching devices can still achieve soft switching at the same time.

   Development of a Novel Six-Inductor Double-Switch PFC Circuit for UPS
By Junping HE [View]
[Download]

Abstract: This paper proposes a three-phase six-inductor double-switch PFC circuit which is suitable for high frequency UPS application. This PFC circuit not only achieves high power factor correction in grid-connected mode of UPS, but also improves bus voltage in battery mode of UPS. This new PFC removes the independent boost design in common UPS and the whole cost can be reduced. The topology structure and working procedures of this PFC circuit are introduced and analyzed in detail. The main circuit parameters and LCL filter are designed for a 5kW PFC prototype. The MATLAB simulation and experiment results show that this PFC circuit is easy to control with less switches, and woks in good input power factor and low current harmonic distortion.

   Efficiency improvement of bidirectional isolated DC/DC converter by current power-factor control
By Naoto IZUMOTO [View]
[Download]

Abstract: We have already proposed the new control method for the bidirectional isolated dc/dc converter. This method is that the output terminals of two single phase bridge inverter A and B are connected through an isolated transformer, and the pulse width of the inverter of higher d.c. voltage is narrowed to make equal the fundamental a.c. voltage of both inverters. For example, to make the a.c. output voltage of both inverters same, the pulse width of the inverter A is 180 degrees and the pulse width of inverter B is narrowed to 110 degrees. In this paper, the control method which enables the efficiency improvement of dc/dc converter by a current power-factor control will be proposed. In this control system, the phase difference control and the pulse width control are used. The phase of the sine wave current is brought to be in phase with the output a.c. voltage of the low d.c. voltage inverter, and as the result the zero-current switching can be realized.

   Extra-low-voltage DC power supply for superconducting coil using piezoelectric-actuator-driven mechanical contact
By Hirotaka CHIKARAISHI [View]
[Download]

Abstract: A helical-type fusion facility uses a large-scale superconducting DC magnet.To maintain the coil current of this magnet during steady-state operation, a large output current supplied by a very-low-voltage power supply is necessary. For this purpose, a DC power supply using a mechanical contact as a switching device was designed, and a small model of the contact was tested.

   Input - series output - series resonant converter with flying capacitor voltage balancing
By Kaspars KROICS [View]
[Download]

Abstract: The multilevel converters have advantages of low voltage stresses of the switches and possible reduction of size of the passive components. Input-series output-series (ISOS) configuration of the converter enable the utilization of low voltage rating switches in converters with high input voltage and high output voltage in applications that requires galvanic isolation. While multilevel topology offers many features, it also necessitates a balance control of the input capacitors. The usage of flying capacitor for voltage balancing is addressed in this paper. The paper discusses design of input-series and output-series resonant converter for discharge lamp power supply. Zero-voltage switching (ZVS) is achieved for each main switch without any auxiliary circuit. First of all the operation of the converter is analyzed on the simulation model and after that the presented converter are verified on experimental prototype with 3 phase AC input voltage and 3 kW output power.

   Multifunctional Energy Storage System for Smart Grid Applications
By Marek MICHALCZUK [View]
[Download]

Abstract: A 15 kVA power electronic system with a battery energy storage system is presented in the paper. The system is designed for areas where a problem with the quality of the electrical power arises. The system is intended for households and small industrial facilities and provides a variety of functionalities such as: ability of providing high quality voltage for the customers load, uninterruptible power supply in the case of power outage, control of the reactive power and low harmonic content of the grid current. An experimental study, that illustrates the functionality of the system, was performed using a full-scale physical model.

   Output Stage Capacitor Aging Detection of Grid Connected Isolating DC-DC Converter
By Janne HANNONEN [View]
[Download]

Abstract: Reliability is one of the key features that is sought after in converter design. Electrolytic capacitors are the most common capacitor type in switching mode power supplies to be used as a DC bus energy storage. However, electrolytic capacitors are known to degrade due to aging. This paper introduces a capacitance degradation detection method for a step-down DC-DC converter that is based on introducing a voltage transient to the output voltage. The method is based on analyzing the voltage step response. The method was verified to be feasible with experimental tests with a grid connected step-down DC-DC converter.

   Reliability Analysis of DC Traction Power Supply System for Electric Railway
By Hitoshi HAYASHIYA [View]
[Download]

Abstract: Dc electric railway is one of the important application fields of low voltage dc power supply. Thereliability analysis of each component in dc power supply system in East Japan Railway Companywhose voltage level is dc 1.5kV was carried out. Such quantitative analysis can realize reasonableproposal of redundant dc circuit configuration. In this paper, the relation between the redundantconfiguration of traction substation circuit and reliability of power supply is calculated. In the last partof this paper, a novel method to convert influence of downtime of railway power supply system to theinfluence cost is proposed and the suitability of such a redundant configuration is confirmed.

   SiC Mosfet transistors in power analog application
By Wojciech MYSINSKI [View]
[Download]

Abstract: The properties of SiC Power Mosfet transistors have been known for years and have been extensively described in the literature. Also, new generations of SiC transistors and diodes are being developed. Power Mosfet transistors are mainly used in power electronics applications in which such transistors operate as controlled switches. In this case, equipment design engineers focus their attention on current and voltage parameters, such as voltage drop across the device and transistor switching speed. Si Mosfet transistors are also sometimes used in analog power applications, e.g. signal amplifiers (acoustic amplifiers), electronic current sources or electronic loads. This article describes an example application of a SiC Mosfet transistor in a current source with capacity of up to 4A. A comparison is provided between static and dynamic characteristics of a current source circuit based on a Si Mosfet transistor and a SiC Mosfet. The article also describes laboratory tests carried out on an actual circuit.

EPE 2017 - DS1k: Power Supplies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 07: Power Supplies > EPE 2017 - DS1k: Power Supplies
	[return to parent folder]

	A Novel Generation Method of Gate Signals for Synchronous Rectification Operation in LLC Resonant Converters By Kyungmin SUNG	[View] [Download]
Abstract: This paper proposes the novel generation method of gate signals to control output voltage in a wide range and to achieve synchronous rectification operating in half-bridge LLC resonant converters. The switching frequency modulation is used in half-bridge LLC resonant converters for control strategy of output voltage. The switching timing of secondary MOSFETs is compensated using the gate signal of primary side by the reference value of switching frequency without any detection circuits. The Current Doubler Synchronous Rectifier (CDSR) and the Center Tapped Synchronous Rectifier (CTSR) are implemented for secondary circuit in the experiment. According to experimental results, not only stable operation in a wide switching frequency range but also the improved conversion efficiency is achieved by the proposed method.

	A Very Low THD and High Power Factor Primary Side Regulation LED Driver By Giovanni GRITTI	[View] [Download]
Abstract: This paper introduces a new power factor correction scheme for a Flyback converter with primary regulation technique, to ideally eliminate the distortion of the ac input current (practically a Total Harmonic Distortion (THD) lower than 5\%). The effectiveness of the new control scheme is proved in a 35W driver with universal input range (90VAC~277VAC). Application target is Solid State Lighting (LED drivers).

	Adjustable Speed Generation System Under Fault Condition By WLODZIMIERZ KOCZARA	[View] [Download]
Abstract: Paper presents performance of the 40kVA autonomous, adjustable speed generation system in a short circuit condition, protected by a B-class tripping switch. Tripping switch is unable to clear the short-circuit event when an inverter current is limited, thus a topology of asynchronous bypass is developed, which delivers additional current directly from permanent magnet generator. Experiments of the laboratory stand that has been carried out, including asynchronous bypass, concludes that the sum of the inverter current and permanent magnet current results in disconnection of the affected load in time less than 20 ms.

	Buck Mode Control Methods of the qZS-Resonant DC/DC Converters By Ivars RANKIS	[View] [Download]
Abstract: The series resonant DC/DC converter with an isolation transformer and bridge mode inverter input junction, at its operation in the Buck case, is investigated, at that input DC supply circuit comprises the qZ (quasi-Z) link as impedance source. Operation at such Buck case can be provided under different inverter bridge control methods. Recommended by the literature sources, is the method of control with rising of switching frequency above the resonant one. Two compromise methods here are proposed too - with phase shift of the bridge legs switching, and the asymmetric control method, when switching pattern of the bridge's switches is asymmetrical in time. Simplified descriptions of processes in the system for before mentioned control principles are presented, as well expressions for approximate calculation of the main parameters of the system at the methods are derived too. Influence of q-Z link properties on restrictions of resonant processes is described. Computer simulations of the operation cases, approving sufficient correctness of the simplifications accepted at analyses, are provided. Comparison of results regarding to the applied control methods, as well some recommendations about application of the systems, is done.

	Contactless Power Transfer in Seawater By MAMIKO INAMORI	[View] [Download]
Abstract: This paper investigates the fundamental characteristics of contactless power transfer in seawater. The influence of seawater on contactless power transfer via magnetic resonant coupling method is experi- mentally examined. The experimental results show that the transmission efficiency decreases about 5\% in seawater compared to that of in air.

	Current-Source PFC based LED Drivers with Electronic-Smoothing Inductor for AC Power Decoupling By Chi Shing WONG	[View] [Download]
Abstract: The paper proposes an electronic-smoothing inductor (ESI) as an energy storage element in current-sourcePFC based LED drivers. In comparison with the passive inductor approach, the required inductancevalue of the overall driver circuit can be significantly reduced such that better power density andefficiency can be achieved. The derivation of different structures of current-source LED drivers by dualityprinciple is also discussed in this paper. The idea is validated by a single-stage, current-boost PFCpre-regulator for low-power LED lighting applications.

	Design of a bi-directional full bridge LLC resonant converter with a higher normalized voltage gain under backward mode By Junping HE	[View] [Download]
Abstract: A step-up control method is proposed to solve the problem of the normalized voltage gain less than 1 when the bi-directional LLC resonant converter works in backward mode. This step-up control method turns on rectifier switches to help resonant components recover their energy and improves the normalized voltage gain to 2. Working principle of the bidirectional LLC resonant converter is introduced firstly. The working procedures under continuous mode and discontinuous mode are analyzed and deduced in detail too. In the end, a 3kW prototype is built up for UPS battery charger application. The MATLAB simulation and experiment results show that this proposed bidirectional LLC resonant circuit works with a high efficiency and the normalized voltage gain can be greater than 1 in the backward operation. Certainly, most of the switching devices can still achieve soft switching at the same time.

	Development of a Novel Six-Inductor Double-Switch PFC Circuit for UPS By Junping HE	[View] [Download]
Abstract: This paper proposes a three-phase six-inductor double-switch PFC circuit which is suitable for high frequency UPS application. This PFC circuit not only achieves high power factor correction in grid-connected mode of UPS, but also improves bus voltage in battery mode of UPS. This new PFC removes the independent boost design in common UPS and the whole cost can be reduced. The topology structure and working procedures of this PFC circuit are introduced and analyzed in detail. The main circuit parameters and LCL filter are designed for a 5kW PFC prototype. The MATLAB simulation and experiment results show that this PFC circuit is easy to control with less switches, and woks in good input power factor and low current harmonic distortion.

	Efficiency improvement of bidirectional isolated DC/DC converter by current power-factor control By Naoto IZUMOTO	[View] [Download]
Abstract: We have already proposed the new control method for the bidirectional isolated dc/dc converter. This method is that the output terminals of two single phase bridge inverter A and B are connected through an isolated transformer, and the pulse width of the inverter of higher d.c. voltage is narrowed to make equal the fundamental a.c. voltage of both inverters. For example, to make the a.c. output voltage of both inverters same, the pulse width of the inverter A is 180 degrees and the pulse width of inverter B is narrowed to 110 degrees. In this paper, the control method which enables the efficiency improvement of dc/dc converter by a current power-factor control will be proposed. In this control system, the phase difference control and the pulse width control are used. The phase of the sine wave current is brought to be in phase with the output a.c. voltage of the low d.c. voltage inverter, and as the result the zero-current switching can be realized.

	Extra-low-voltage DC power supply for superconducting coil using piezoelectric-actuator-driven mechanical contact By Hirotaka CHIKARAISHI	[View] [Download]
Abstract: A helical-type fusion facility uses a large-scale superconducting DC magnet.To maintain the coil current of this magnet during steady-state operation, a large output current supplied by a very-low-voltage power supply is necessary. For this purpose, a DC power supply using a mechanical contact as a switching device was designed, and a small model of the contact was tested.

	Input - series output - series resonant converter with flying capacitor voltage balancing By Kaspars KROICS	[View] [Download]
Abstract: The multilevel converters have advantages of low voltage stresses of the switches and possible reduction of size of the passive components. Input-series output-series (ISOS) configuration of the converter enable the utilization of low voltage rating switches in converters with high input voltage and high output voltage in applications that requires galvanic isolation. While multilevel topology offers many features, it also necessitates a balance control of the input capacitors. The usage of flying capacitor for voltage balancing is addressed in this paper. The paper discusses design of input-series and output-series resonant converter for discharge lamp power supply. Zero-voltage switching (ZVS) is achieved for each main switch without any auxiliary circuit. First of all the operation of the converter is analyzed on the simulation model and after that the presented converter are verified on experimental prototype with 3 phase AC input voltage and 3 kW output power.

	Multifunctional Energy Storage System for Smart Grid Applications By Marek MICHALCZUK	[View] [Download]
Abstract: A 15 kVA power electronic system with a battery energy storage system is presented in the paper. The system is designed for areas where a problem with the quality of the electrical power arises. The system is intended for households and small industrial facilities and provides a variety of functionalities such as: ability of providing high quality voltage for the customers load, uninterruptible power supply in the case of power outage, control of the reactive power and low harmonic content of the grid current. An experimental study, that illustrates the functionality of the system, was performed using a full-scale physical model.

	Output Stage Capacitor Aging Detection of Grid Connected Isolating DC-DC Converter By Janne HANNONEN	[View] [Download]
Abstract: Reliability is one of the key features that is sought after in converter design. Electrolytic capacitors are the most common capacitor type in switching mode power supplies to be used as a DC bus energy storage. However, electrolytic capacitors are known to degrade due to aging. This paper introduces a capacitance degradation detection method for a step-down DC-DC converter that is based on introducing a voltage transient to the output voltage. The method is based on analyzing the voltage step response. The method was verified to be feasible with experimental tests with a grid connected step-down DC-DC converter.

	Reliability Analysis of DC Traction Power Supply System for Electric Railway By Hitoshi HAYASHIYA	[View] [Download]
Abstract: Dc electric railway is one of the important application fields of low voltage dc power supply. Thereliability analysis of each component in dc power supply system in East Japan Railway Companywhose voltage level is dc 1.5kV was carried out. Such quantitative analysis can realize reasonableproposal of redundant dc circuit configuration. In this paper, the relation between the redundantconfiguration of traction substation circuit and reliability of power supply is calculated. In the last partof this paper, a novel method to convert influence of downtime of railway power supply system to theinfluence cost is proposed and the suitability of such a redundant configuration is confirmed.

	SiC Mosfet transistors in power analog application By Wojciech MYSINSKI	[View] [Download]
Abstract: The properties of SiC Power Mosfet transistors have been known for years and have been extensively described in the literature. Also, new generations of SiC transistors and diodes are being developed. Power Mosfet transistors are mainly used in power electronics applications in which such transistors operate as controlled switches. In this case, equipment design engineers focus their attention on current and voltage parameters, such as voltage drop across the device and transistor switching speed. Si Mosfet transistors are also sometimes used in analog power applications, e.g. signal amplifiers (acoustic amplifiers), electronic current sources or electronic loads. This article describes an example application of a SiC Mosfet transistor in a current source with capacity of up to 4A. A comparison is provided between static and dynamic characteristics of a current source circuit based on a Si Mosfet transistor and a SiC Mosfet. The article also describes laboratory tests carried out on an actual circuit.