scholarly journals Analysis of a Series‑Parallel Resonant Converter for DC Microgrid Applications

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 542
Author(s):  
Bor-Ren Lin
Keyword(s):  
Low Voltage ◽  
Magnetic Coupling ◽  
Input Voltage ◽  
Soft Switching ◽  
Parallel Structure ◽  
Resonant Circuit ◽  
Resonant Converter ◽  
Dc Microgrid ◽  
Power Semiconductors ◽  
Power Diodes

An input-series output-parallel soft switching resonant circuit with balance input voltage and primary-side current is studied and implemented for direct current (DC) microgrid system applications. Two resonant circuits are connected with input-series and output-parallel structure to have the advantages of low voltage stresses on active devices and low current stresses on power diodes. A balance capacitor is adopted on high voltage side to balance two input capacitor voltages. The LLC (inductor–inductor–capacitor) resonant circuit cells are employed in the converter to have soft switching operation for power semiconductors. The magnetic coupling component is adopted on the primary-side to automatically realize current balance of the two resonant circuits. In the end, a laboratory hardware circuit is built and tested. Experiments demonstrate and prove the validity of the resonant converter.

scholarly journals Analysis of a Wide Voltage Hybrid Soft Switching Converter

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 473 ◽  
Author(s):  
Bor-Ren Lin ◽  
Yen-Chun Liu
Keyword(s):  
Power Conversion ◽  
Input Voltage ◽  
Soft Switching ◽  
Resonant Converter ◽  
Solar Pv ◽  
Load Range ◽  
Pwm Converter ◽  
Load Voltage ◽  
Zero Voltage Switching ◽  
Circulating Current

A hybrid PWM converter is proposed and investigated to realize the benefits of wide zero-voltage switching (ZVS) operation, wide voltage input operation, and low circulating current for direct current (DC) wind power conversion and solar PV power conversion applications. Compared to the drawbacks of high freewheeling current and hard switching operation of active devices at the lagging-leg of conventional full bridge PWM converter, a three-leg PWM converter is studied to have wide input-voltage operation (120–600 V). For low input-voltage condition (120–270 V), two-leg full bridge converter with lower transformer turns ratio is activated to control load voltage. For high input-voltage case (270–600 V), PWM converter with higher transformer turns ratio is operated to regulate load voltage. The LLC resonant converter is connecting to the lagging-leg switches in order to achieve wide load range of soft switching turn-on operation. The high conduction losses at the freewheeling state on conventional full bridge converter are overcome by connecting the output voltage of resonant converter to the output rectified terminal of full bridge converter. Hence, a 5:1 (600–120 V) hybrid converter is realized to have less circulating current loss, wide input-voltage operation and wide soft switching characteristics. An 800 W prototype is set up and tested to validate the converter effectiveness.

scholarly journals Analysis and Design of Coupled Inductor for Interleaved Buck-Type Voltage Balancer in Bipolar DC Microgrid

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2775
Author(s):  
Jung-min Park ◽  
Hyung-jun Byun ◽  
Bum-jun Kim ◽  
Sung-hun Kim ◽  
Chung-yuen Won
Keyword(s):  
Dynamic Response ◽  
Coupling Coefficient ◽  
Distribution System ◽  
Low Voltage ◽  
Magnetic Coupling ◽  
Two Stage ◽  
Dc Microgrid ◽  
Analysis And Design ◽  
Load Variation ◽  
Key Factor

A voltage balancer (VB) can be used to balance voltages under load unbalance in either a bipolar DC microgrid or LVDC (Low voltage DC) distribution system. An interleaved buck-type VB has advantages over other voltage balance topologies for reduction in output current ripple by an aspect of configuration of a physically symmetrical structure. Similarly, magnetic coupling such as winding two or more magnetic components into a single magnetic component can be selected to enhance the power density and dynamic response. In order to achieve these advantages in a VB, this paper proposes a VB with a coupled inductor (CI) as a substitute for inductors in a two-stage interleaved buck-type VB circuit. Based on patterns of switch poles under load variation, the variation in inductor currents under four switching patterns is induced. The proposed CI is derived from self-inductance based on the configuration structure that has a two-stage interleaved buck type and mathematical design results based on the coupling coefficient, where the coupling coefficient is a key factor in the determination of the dynamic response of the proposed VB in load variation. According to the results, a prototype scale is implemented to confirm the feasibility and effectiveness of the proposed VB.

scholarly journals Hybrid LLC Converter with Wide Range of Zero-Voltage Switching and Wide Input Voltage Operation

2020 ◽  
Vol 10 (22) ◽  
pp. 8250
Author(s):  
Bor-Ren Lin ◽  
Kun-Yi Chen
Keyword(s):  
Low Voltage ◽  
Input Voltage ◽  
Resonant Circuit ◽  
Zero Voltage Switching ◽  
Photovoltaic Energy Conversion ◽  
Wide Range ◽  
Input Side ◽  
Input Region ◽  
Output Side ◽  
Zero Voltage

A new hybrid inductor-inductor-capacitor (LLC) converter is investigated to have wide voltage input operation capability and zero-voltage turn-on characteristics. The presented circuit topology can be applied for consumer power units without power factor correction or with long hold-up time requirement, photovoltaic energy conversion and renewable energy power transfer. To overcome the weakness of narrow voltage gain of resonant converter, the hybrid LLC converter with different turns ratio of transformer is presented and the experimental investigation is provided to achieve wide voltage input capability (400 V–50 V). On the input-side, the converter can operate as full bridge resonant circuit or half bridge resonant circuit with input split capacitors for high or low voltage input region. On the output-side, the less or more winding turns is selected to overcome wide voltage input operation. According to the circuit structures and transformer turns ratio, the single stage LLC converter with wide voltage input operation capability (400 V–50 V) is accomplished. The laboratory prototype has been developed and the experimental waveforms are measured and demonstrated to investigate the effectiveness of the presented hybrid LLC converter.

scholarly journals Bidirectional Resonant Converter for DC Microgrid Applications

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1664
Author(s):  
Bor-Ren Lin
Keyword(s):  
Electric Vehicle ◽  
Output Voltage ◽  
Resonant Circuit ◽  
Resonant Converter ◽  
Battery Charger ◽  
Dc Microgrid ◽  
Voltage Range ◽  
Zero Voltage Switching ◽  
Active Devices ◽  
Power Operation

A bidirectional resonant converter is presented and verified in this paper for an electric vehicle battery charger/discharger system. The presented circuit can achieve forward and backward power operation, low switching losses on active devices, and wide output voltage operation. The circuit structure of the presented converter includes two resonant circuits on the primary and secondary sides of an isolated transformer. The frequency modulation approach is adopted to control the studied circuit. Owing to the resonant circuit characteristic, active devices for both forward (battery charge) and backward (battery discharge) power operation can be turned on at zero voltage switching. In order to implement a universal battery charger for different kinds of electric vehicle applications, the DC converter is demanded to have a wide output voltage range capability. The topology morphing between a full bridge resonant circuit and half bridge resonant circuit is selected to obtain high- and low-output voltage range operations so that the 200–500 V output voltage range is realized in the presented resonant converter. Compared to the conventional bidirectional converters, the proposed can be operated under a wide voltage range operation. In the end, a 1 kW laboratory prototype circuit is built, and experiments are provided to demonstrate the validity and performance of the presented bidirectional resonant converter.

scholarly journals Resonant Converter with Soft Switching and Wide Voltage Operation

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3479 ◽  
Author(s):  
Bor-Ren Lin
Keyword(s):  
Output Voltage ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Resonant Converters ◽  
Resonant Converter ◽  
Switching Loss ◽  
Voltage Range ◽  
Power Diodes ◽  
Switching Losses ◽  
In Series

A new DC/DC resonant converter with wide output voltage range operation is presented and studied to have the benefits of low switching losses on active devices and low voltage stresses on power diodes. To overcome serious reverse recovery losses of power diodes on a conventional full-bridge pulse-width modulation converter, the resonant converter is adopted to reduce the switching loss and increase the circuit efficiency. To extend the output voltage range in conventional half-bridge or full-bridge resonant converters, the secondary sides of two diode rectifiers are connected in series to have wide output voltage operation. The proposed converter can be either operated at one-resonant-converter mode for low voltage range or two-resonant-converter mode for high voltage range. Thus, the voltage rating of power diodes is decreased. Experiments with the design example are given to show the circuit performance and validate the theoretical discussion and analysis.

scholarly journals Analysis and Implementation of a Hybrid DC Converter with Wide Voltage Variation

2021 ◽  
Vol 11 (21) ◽  
pp. 10211
Author(s):  
Bor-Ren Lin ◽  
Yue-Ying Zhuang
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Input Voltage ◽  
Pulse Frequency ◽  
Resonant Circuit ◽  
Bridge Structure ◽  
Pulse Frequency Modulation ◽  
Switching Losses ◽  
Voltage Variation ◽  
Bidirectional Power Flow

A new hybrid DC converter is proposed and implemented to have wide voltage variation operation and bidirectional power flow capability for photovoltaic power applications. The hybrid DC converter, including a half- or full-bridge resonant circuit, is adopted to realize the bidirectional power operation and low switching losses. To overcome the wide voltage variation problem (60 V–480 V) from photovoltaic panels due to sunlight intensity, the full-bridge structure or half-bridge structure resonant circuit is used in the presented converter to implement high or low voltage gain under a low or high input voltage condition. Using a pulse frequency modulation (PFM) scheme, the voltage transfer function of the resonant circuit is controlled to regulate the load voltage. Due to the symmetric circuit structures used on the primary and the secondary sides in the proposed converter, the bidirectional power flow can be achieved with the same circuit characteristics. Therefore, the proposed converter can be applied to battery stacks to achieve charger and discharger operations. Finally, a 400 W prototype is implemented, and the performance of the proposed hybrid DC converter is confirmed by the experiments.

scholarly journals Asymmetric snubberless current-fed full-bridge isolated DC-DC converters

2018 ◽  
Vol 14 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Roman Kosenko ◽  
Andrei Blinov ◽  
Dmitri Vinnikov ◽  
Andrii Chub
Keyword(s):  
Low Voltage ◽  
Operating Conditions ◽  
Voltage Source ◽  
Resonant Circuit ◽  
Dc Microgrid ◽  
Leakage Inductance ◽  
Active Rectifier ◽  
Shift Control ◽  
Steady State Operation ◽  
Wide Range

Abstract This paper presents two isolated current-fed fullbridge DC-DC converters that can be used to interface a lower voltage source into a DC bus of higher voltage. The first topology uses a resonant circuit to force current redistribution between low-voltage-side transistors and a passive rectifier. The second topology utilizes an active rectifier with secondary modulation to achieve the same goal. The resonant circuit can be formed by using transformer leakage inductance and the parasitic capacitances of the switches. The converters feature soft switching of semiconductors over a wide range of operating conditions. This is achieved with decreased energy circulation when compared to existing topologies with symmetric control and with fewer semiconductors than in those with phase-shift control. The topologies can be implemented in renewable, supercapacitor, battery, fuel cell, and DC microgrid applications. Steady-state operation and design aspects of the converters are presented and verified experimentally with 400 W prototypes

Bidirectional Resonant DC-DC converter for Microgrid Applications

2017 ◽  
Vol 8 (4) ◽  
pp. 1548 ◽  
Author(s):  
Jaisudha S. ◽  
Sowmiya Srinivasan ◽  
Kanimozhi Gunasekaran
Keyword(s):  
Soft Switching ◽  
Resonant Circuit ◽  
Voltage Gain ◽  
Dc Microgrid ◽  
Turn On ◽  
High Voltage Gain ◽  
Zero Current ◽  
Snubber Circuit ◽  
Capacitive Divider ◽  
Voltage Doubler

<p>This paper proposes a non-isolated soft-switching bidirectional dc/dc converter for interfacing energy storage in DC microgrid. The proposed converter employs a half-bridge boost converter at input port followed by a LCC resonant tank to assist in soft-switching of switches and diodes, and finally a voltage doubler circuit at the output port to enhance the voltage gain by two times. The LCC resonant circuit also adds a suitable voltage gain to the converter. Therefore, overall high voltage gain of the converter is obtained without a transformer or large number of multiplier circuit. For operation in buck mode, the high side voltage is divided by half with capacitive divider to gain higher step-down ratio. The converter is operated at high frequency to obtain low output voltage ripple, reduced magnetics and filters. Zero voltage turn-on is achieved for all switches and zero current turn-on and turn-off is achieved for all diodes in both modes i.e., buck/boost operation. Voltage stress across switches and diode is clamped naturally without external snubber circuit. An experimental prototype has been designed, built and tested in the laboratory to verify the performance of the proposed converter.</p>

scholarly journals DC Converter with Wide Soft Switching Operation, Wide Input Voltage and Low Current Ripple

2020 ◽  
Vol 10 (13) ◽  
pp. 4672 ◽  
Author(s):  
Bor-Ren Lin ◽  
Guan-Hong Lin
Keyword(s):  
Pulse Width Modulation ◽  
Current Source ◽  
Input Voltage ◽  
Soft Switching ◽  
Resonant Converter ◽  
Pwm Converter ◽  
Input Side ◽  
Output Side ◽  
Zero Voltage ◽  
Current Ripple

A soft switching current-source resonant converter is presented and implemented for wide voltage applications such as fuel cells and solar power. An LLC (inductor–inductor–capacitor) converter is adopted to accomplish zero voltage (current) operation on active switches (diodes). Thus, the circuit efficiency is increased. The interleaved pulse-width modulation (PWM) converter is employed on the input side to accomplish low input ripple current. A hybrid LLC converter is adopted to achieve wide voltage operation from Vin, min to 4Vin, min and to improve the weakness of a conventional LLC converter. Half-bridge diode rectification is employed on the output side to decrease power loss on the rectifier diode. To confirm the theoretical analysis and feasibility, experimental verifications with a 500-W prototype are demonstrated in this paper.

scholarly journals Soft Switching DC Converter for Medium Voltage Applications

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 449 ◽  
Author(s):  
Bor-Ren Lin
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Soft Switching ◽  
Parallel Structure ◽  
Dc Microgrid ◽  
Medium Voltage ◽  
Voltage Balance ◽  
Power Switches ◽  
Asymmetric Pulse ◽  
Secondary Side

A dc-dc converter with asymmetric pulse-width modulation is presented for medium voltage applications, such as three-phase ac-dc converters, dc microgrid systems, or dc traction systems. To overcome high voltage stress on primary side and high current rating on secondary side, three dc-dc circuits with primary-series secondary-parallel structure are employed in the proposed converter. Current doubler rectifiers are used on the secondary side to achieve low ripple current on output side. Asymmetric pulse-width modulation is adopted to realize soft switching operation for power switches for wide load current operation and achieve high circuit efficiency. Current balancing cells with magnetic component are used on the primary side to achieve current balance in each circuit cell. The voltage balance capacitors are also adopted on primary side to realize voltage balance of input split capacitors. Finally, the circuit performance is confirmed and verified from the experiments with a 1.44 kW prototype.

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