scholarly journals Implementation of a Resonant Converter with Topology Morphing to Achieve Bidirectional Power Flow

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5186
Author(s):  
Bor-Ren Lin
Keyword(s):  
Fuel Cell ◽  
Power Flow ◽  
Bridge Circuit ◽  
Input Voltage ◽  
Switching Frequency ◽  
Switching Loss ◽  
Dc Voltage ◽  
Cell Energy ◽  
Power Capability ◽  
Bidirectional Power Flow

A DC converter with the benefits of reverse power capability, less switching loss and wide voltage operation is presented and implemented for wide input voltage applications such as fuel cell energy, photovoltaic (PV) system and DC wind power. Two full bridge resonant circuits are used in the presented converter to achieve bidirectional power flow capability and reduce switching losses on active devices. To overcome the wide input DC voltage variation problem for fuel cell energy and PV solar panel, the topology morphing between the half bridge circuit and full bridge circuit is adopted on the primary side to obtain low (or high) voltage gain under a high (or low) input voltage condition. Therefore, the stable DC voltage is controlled at the load side by using the variable switching frequency modulation. The studied hybrid CLLC converter is tested by a 1 kW prototype and the performance is verified and confirmed by experiments.

scholarly journals Optimal Modulation Techniques of a DAB Based Isolated Bidirectional Single-stage Single-phase AC-DC Converter

2021 ◽  
Author(s):  
Dibakar Das ◽  
Kaushik Basu ◽  
Sayan Paul
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Degrees Of Freedom ◽  
Single Phase ◽  
Single Stage ◽  
Switching Frequency ◽  
Switching Loss ◽  
Two Stage ◽  
Wide Range ◽  
Bidirectional Power Flow

A bidirectional single-phase AC to DC converter with high-frequency isolation finds a wide range of applications, including charging electric vehicles in the vehicle to grid applications. A conventional two-stage solution, where an AC-DC front-end rectifier is connected to an isolated DC-DC converter, suffers from poor efficiency due to hard switching of the AC-DC stage and poor reliability due to the existence of an electrolytic capacitance at the interstage DC link. A Dual Active Bridge (DAB) based single-stage AC-DC converter with a potential of bidirectional power flow can overcome the problems of a two stage solution. A rich literature exists in search for finding an efficient modulation strategy for this converter. This paper presents two constant switching frequency modulation strategies that support bidirectional power flow at any power factor utilizing all three degrees of freedom in modulation, also known as triple phase-shift modulation (TPS). One of the strategies minimizes RMS high-frequency transformer current over the line cycle, and the other one optimizes peak current. Hence, the conduction loss and the component stress over the entire line cycle are minimized. ZVS conditions are met for all high-frequency switching devices for the whole operating region, while the AC side converter is line frequency switched, incurring negligible switching loss. AC line current waveforms are of high quality and free from low-frequency harmonics. UPF operation is of importance for single-phase power conversion. All possible modes that the converter will experience over a line cycle for UPF operation are elaborated through detailed analysis. The proposed strategies are validated through experiment and simulation with 230 V, 50 Hz AC grid, 400 V DC, UPF, and output power of 1.2 kW.

scholarly journals Optimal Modulation Techniques of a DAB Based Isolated Bidirectional Single-stage Single-phase AC-DC Converter

2021 ◽  
Author(s):  
Dibakar Das ◽  
Kaushik Basu ◽  
Sayan Paul
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Degrees Of Freedom ◽  
Single Phase ◽  
Single Stage ◽  
Switching Frequency ◽  
Switching Loss ◽  
Two Stage ◽  
Wide Range ◽  
Bidirectional Power Flow

A bidirectional single-phase AC to DC converter with high-frequency isolation finds a wide range of applications, including charging electric vehicles in the vehicle to grid applications. A conventional two-stage solution, where an AC-DC front-end rectifier is connected to an isolated DC-DC converter, suffers from poor efficiency due to hard switching of the AC-DC stage and poor reliability due to the existence of an electrolytic capacitance at the interstage DC link. A Dual Active Bridge (DAB) based single-stage AC-DC converter with a potential of bidirectional power flow can overcome the problems of a two stage solution. A rich literature exists in search for finding an efficient modulation strategy for this converter. This paper presents two constant switching frequency modulation strategies that support bidirectional power flow at any power factor utilizing all three degrees of freedom in modulation, also known as triple phase-shift modulation (TPS). One of the strategies minimizes RMS high-frequency transformer current over the line cycle, and the other one optimizes peak current. Hence, the conduction loss and the component stress over the entire line cycle are minimized. ZVS conditions are met for all high-frequency switching devices for the whole operating region, while the AC side converter is line frequency switched, incurring negligible switching loss. AC line current waveforms are of high quality and free from low-frequency harmonics. UPF operation is of importance for single-phase power conversion. All possible modes that the converter will experience over a line cycle for UPF operation are elaborated through detailed analysis. The proposed strategies are validated through experiment and simulation with 230 V, 50 Hz AC grid, 400 V DC, UPF, and output power of 1.2 kW.

scholarly journals Step-Up Series Resonant DC–DC Converter with Bidirectional-Switch-Based Boost Rectifier for Wide Input Voltage Range Photovoltaic Applications

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3747 ◽  
Author(s):  
Abualkasim Bakeer ◽  
Andrii Chub ◽  
Dmitri Vinnikov
Keyword(s):  
Theoretical Analysis ◽  
Duty Cycle ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Switching Frequency ◽  
Voltage Gain ◽  
Voltage Range ◽  
Dc Voltage ◽  
Wide Range ◽  
Series Resonant

This paper proposes a high gain DC–DC converter based on the series resonant converter (SRC) for photovoltaic (PV) applications. This study considers low power applications, where the resonant inductance is usually relatively small to reduce the cost of the converter realization, which results in low-quality factor values. On the other hand, these SRCs can be controlled at a fixed switching frequency. The proposed topology utilizes a bidirectional switch (AC switch) to regulate the input voltage in a wide range. This study shows that the existing topology with a bidirectional switch has a limited input voltage regulation range. To avoid this issue, the resonant tank is rearranged in the proposed converter to the resonance capacitor before the bidirectional switch. By this rearrangement, the dependence of the DC voltage gain on the duty cycle is changed, so the proposed converter requires a smaller duty cycle than that of the existing counterpart at the same gain. Theoretical analysis shows that the input voltage regulation range is extended to the region of high DC voltage gain values at the maximum input current. Contrary to the existing counterpart, the proposed converter can be realized with a wide range of the resonant inductance values without compromising the input voltage regulation range. Nevertheless, the proposed converter maintains advantages of the SRC, such as zero voltage switching (ZVS) turn-on of the primary-side semiconductor switches. In addition, the output-side diodes are turned off at zero current. The proposed converter is analyzed and compared with the existing counterpart theoretically and experimentally. A 300 W experimental prototype is used to validate the theoretical analysis of the proposed converter. The peak efficiency of the converter is 96.5%.

scholarly journals X-Type Step-Up Multi-Level Inverter with Reduced Component Count Based on Switched-Capacitor Concept

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1987
Author(s):  
Erfan Azimi ◽  
Aryorad Khodaparast ◽  
Mohammad Javad Rostami ◽  
Jafar Adabi ◽  
M. Ebrahim Adabi ◽  
...  
Keyword(s):  
Power Flow ◽  
Input Voltage ◽  
Switching Frequency ◽  
Switched Capacitor ◽  
Level Control ◽  
Voltage Balancing ◽  
Simulink Model ◽  
Wide Range ◽  
Multi Level ◽  
Laboratory Prototype

This paper aims to present a novel switched-capacitor multi-level inverter. The presented structure generates a staircase near sinusoidal AC voltage by using a single DC source and a few capacitors to step-up the input voltage. The nearest level control (NLC) strategy is used to control the operation of the converter. These switching states are designed in a way that they always ensure the self-voltage balancing of the capacitors. Low switching frequency, simple control, and inherent bipolar output are some of the advantages of the presented inverter. Compared to other existing topologies, the structure requires fewer circuit elements. Bi-directional power flow ability of the proposed topology, facilitates the operation of the circuit under wide range of load behaviors which makes it applicable in most industries. Besides, a 13-level laboratory prototype is implemented to realize and affirm the efficacy of the MATLAB Simulink model under different load conditions. The simulation and experimental results accredit the appropriate performance of the converter. Finally, a theoretical efficiency of 92.73% is reached.

scholarly journals Design of Three Phase Solid State Transformer Deployed within Multi-Stage Power Switching Converters

2019 ◽  
Vol 9 (17) ◽  
pp. 3545 ◽  
Author(s):  
Umair Tahir ◽  
Ghulam Abbas ◽  
Dan Glavan ◽  
Valentina Balas ◽  
Umar Farooq ◽  
...  
Keyword(s):  
Solid State ◽  
Power Flow ◽  
Harmonic Distortion ◽  
Iron Core ◽  
Switching Frequency ◽  
Switching Converters ◽  
Renewable Energy Resources ◽  
Solid State Transformer ◽  
Power Switching ◽  
Bidirectional Power Flow

This paper presents a symmetrical topology for the design of solid-state transformer; made up of power switching converters; to replace conventional bulky transformers. The proposed circuitry not only reduces the overall size but also provides power flow control with the ability to be interfaced with renewable energy resources (RESs) to fulfill the future grid requirements at consumer end. The proposed solid-state transformer provides bidirectional power flow with variable voltage and frequency operation and has the ability to maintain unity power factor; and total harmonic distortion (THD) of current for any type of load within defined limits of Institute of Electrical and Electronics Engineers (IEEE) standard. Solid state transformer offers much smaller size compared to the conventional iron core transformer. MATLAB/Simulink platform is adopted to test the validity of the proposed circuit for different scenarios by providing the simulation results evaluated at 25 kHz switching frequency.

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.

Performance Characterization of the Novel Topology for High-Frequency Isolation Bi-Directional DC/DC Converter

2013 ◽  
Vol 273 ◽  
pp. 305-309 ◽  
Author(s):  
Peng Hui Jing ◽  
Cong Wang ◽  
Jun Wang ◽  
Feng Zhao
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Control Strategies ◽  
High Reliability ◽  
Input Voltage ◽  
Phase Shifting ◽  
Matlab Simulation ◽  
High Input ◽  
The Cost ◽  
Bidirectional Power Flow

A novel topology of high-frequency isolation bi-directional DC/DC converter used in high-Input low-output system was proposed, which has not only the advantages, such as enabling bidirectional power flow, ease of realizing soft-switching control, galvanic isolation, high reliability and so on, but also can be used in high-input voltage application and apparently decreases the stress of the switches, which reduces the cost of the converter, improves power density and the efficiency of the converter. According to the different work condition, two control strategies are analyzed in this paper: the traditional phase shifting control (TPC) and PWM plus phase shifting control (PPC), which further improves the overall efficiency of the converter. The MATLAB simulation has been done to verify the feasibility of the proposed DC/DC converter and accuracy of the criterion.

The Control Strategy of Establishing the Voltage of DC Side in MMC

2013 ◽  
Vol 756-759 ◽  
pp. 292-297
Author(s):  
Ming Ma ◽  
Gang Peng ◽  
Jun Wei Hao ◽  
Jing Jing Lu ◽  
Chang Yuan ◽  
...  
Keyword(s):  
Control Strategy ◽  
Balance Control ◽  
Voltage Control ◽  
Switching Frequency ◽  
Switching Loss ◽  
Dc Voltage ◽  
High Switching Frequency ◽  
Voltage Balance ◽  
Dc Voltage Control ◽  
Voltage Balance Control

This paper discusses the establishing method of DC voltage of modular multilevel converter (MMC). Firstly the structure of MMC and the charging principle of sub-modules (SMs) are introduced in order to control the DC voltage of MMC and reduce the switching loss. It is pointed out that the DC voltage control in MMC includes two parts, the DC voltage establishment of system and the voltages control of SMs. For the DC voltage control in system, the control theory is analyzed, and the corresponding control strategy is proposed. Meanwhile an improved voltage balance control strategy for SM is proposed by the improvements of the traditional voltage sorting method to reduce the high switching frequency caused by the blind action of switching devices in the SM control. Finally, the simulation results based on PSCAD/EMTDC show that DC voltage in MMC can run in the rated value steadily, and the switching frequency is reduced significantly.

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