scholarly journals Novel High-Efficiency Three-Port Bidirectional Step-Up/Step-Down DC–DC Converter for Photovoltaic Systems

2021 ◽  
Vol 13 (14) ◽  
pp. 7913
Author(s):  
Yu-En Wu ◽  
Shiu-Liang Hsiao
Keyword(s):  
High Efficiency ◽  
Leakage Inductance ◽  
Pv Systems ◽  
Bidirectional Converter ◽  
Measurement Results ◽  
Power Switches ◽  
Step Down ◽  
Dc Bus ◽  
Voltage Spike ◽  
Secondary Side

This paper presents a novel high-efficiency three-port bidirectional DC–DC converter for photovoltaic (PV) systems. A PV system’s output is stepped up to supply a DC bus or DC load while charging the battery. When the PV output is insufficient, the battery voltage is stepped up to the DC bus; when the DC bus has excess energy, it is stepped down to charge the battery. Thus, a high-efficiency three-port bidirectional step-up/step-down converter is achieved. A common-core coupled inductor was designed and adopted in the proposed converter. Power switches and diodes in the circuit are shared to achieve bidirectional operation. In step-up mode, the clamp capacitor is used to reduce the voltage spike on the main switches. Moreover, the voltage-doubling capacitor recovers energy from the secondary-side leakage inductance. Furthermore, the input capacitors recover the primary-side leakage inductance energy in step-down mode. Thus, the converter can improve its conversion efficiency. Finally, this paper details the implementation of a 500 W three-port bidirectional converter to verify the feasibility and the practicability of the proposed topology. According to the measurement results, the highest efficiency levels of the PV and the battery in step-up mode were 94.3% and 94.1%, respectively; the highest efficiency in step-down mode was 95.2%.

scholarly journals Novel Three-Port Bidirectional DC/DC Converter with Three-Winding Coupled Inductor for Photovoltaic System

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1132 ◽  
Author(s):  
Yu-En Wu ◽  
Kai-Cheng Hsu
Keyword(s):  
Photovoltaic System ◽  
Pv System ◽  
Leakage Inductance ◽  
Bidirectional Converter ◽  
Power Switches ◽  
System Output ◽  
Step Down ◽  
Dc Bus ◽  
Bus Voltage ◽  
Voltage Spike

This study proposes a novel three-port bidirectional converter with a three-winding coupled inductor and applies it to a photovoltaic (PV) system to step up the PV system output to a dc bus or dc load while charging the battery. When the PV output is insufficient, battery voltage is stepped up to the dc bus voltage, and when the dc bus has excess energy, it is stepped down to charge the battery. Thus, a three-port bidirectional high step-up/step-down converter is achieved. A three-winding common core coupled inductor is designed and implemented in the converter, and a full-wave doubler circuit is used on the high-voltage side to achieve a high step-up effect. Power switches and diodes in the circuit are shared to achieve bidirectional operation. The output capacitors recover secondary-side leakage inductance energy in the step-up mode, and the third winding can be used to recover primary-side leakage inductance energy to reduce the voltage spike on switching in order to improve the converter’s conversion efficiency. A 500-W three-port bidirectional converter is implemented to verify the feasibility and practicability of the proposed topology. According to the measurement results, the highest efficiency of the PV step-up mode is 95.3%, the highest efficiency of the battery step-up mode is 94.1%, and the highest efficiency of the step-down mode is 94.8%.

scholarly journals Design and Implementation of Improved High Step-Down DC-DC Converter for Electric Vehicles

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4206
Author(s):  
Dong-Ryeol Park ◽  
Yong Kim
Keyword(s):  
Electric Vehicles ◽  
High Efficiency ◽  
Low Voltage ◽  
Switching Frequency ◽  
Switching Loss ◽  
High Switching Frequency ◽  
Voltage Stress ◽  
Power Switches ◽  
Step Down ◽  
Secondary Side

An improved high step-down DC-DC converter for charging the batteries in an electric vehicle application is proposed in this paper. It adopts the topology of the conventional full-bridge converter, which has a coupled inductor current-doubler rectifier as the secondary side of the transformer. In addition, four power switches are driven using a phase-shifting technique. The proposed converter can achieve a high step-down voltage with low-voltage stress on the rectifier diodes. In addition, the coupled inductor current-doubler rectifier of the secondary side can reduce the ripple current and losses of the secondary side to achieve high efficiency. Furthermore, the proposed converter can overcome the drawbacks of the conventional full-bridge converter, such as switching loss caused by high switching frequency, duty-cycle loss, voltage stress, and numerous components, and can increase the efficiency with the soft-switching technique. A 600 W laboratory prototype of the proposed converter was manufactured. The results of the experiments performed with the prototype proved the effectiveness and validated the use of the proposed converter for better charging of electric vehicles.

scholarly journals Design of a High Efficiency High Step-Up/Step-Down Bidirectional Isolated DC–DC Converter

Processes ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 50
Author(s):  
Yu-En Wu ◽  
Pin-Jyun Lin
Keyword(s):  
Energy Conversion ◽  
High Efficiency ◽  
Low Voltage ◽  
Maximum Energy ◽  
Production Costs ◽  
Iron Core ◽  
Zero Voltage Switching ◽  
Bidirectional Converter ◽  
Step Down ◽  
Conversion Efficiencies

This paper presents a novel bidirectional DC–DC converter, equipped with a three-winding coupled inductor, that can be applied to high-voltage, bidirectional DC–DC energy conversion and meet battery charging and discharging requirements. The architecture consists of a semi-Z-source converter and a forward–flyback converter featuring a three-winding coupled inductor with an iron core. This proposed topology retains the current continuity characteristics of the low-voltage side, all switches possess the zero-voltage switching feature, and the switches on the low-voltage side in the step-down mode have a synchronous rectification function. A 500-W bidirectional converter is implemented to examine the practicality and feasibility of the proposed topology. The relatively streamlined design of the converter can greatly reduce production costs. In the step-up and step-down modes, the maximum energy conversion efficiencies are 95.74% and 96.13%, respectively.

ISOLATED HIGH STEP-UP ZERO-VOLTAGE-SWITCHING DC-DC CONVERTER WITH A CONTINUOUS INPUT CURRENT

2011 ◽  
Vol 20 (08) ◽  
pp. 1619-1635 ◽  
Author(s):  
HYUN-LARK DO
Keyword(s):  
High Efficiency ◽  
Input Current ◽  
Leakage Inductance ◽  
Zero Voltage Switching ◽  
Analysis And Design ◽  
High Voltage Gain ◽  
Power Switches ◽  
Continuous Input ◽  
Zero Voltage ◽  
Voltage Switching

An isolated high step-up DC-DC converter with a continuous input current is proposed. The proposed converter consists of two converter cells — a boost converter cell at the input stage for a low input current ripple and a DC-DC converter cell for high voltage gain. Zero-voltage-switching of power switches are achieved and the leakage inductance of the transformer alleviates the reverse-recovery problems of the output diodes. Therefore, the proposed converter achieves high efficiency. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed, and its experimental results are presented for validation.

scholarly journals High-Frequency LLC Resonant Converter with GaN Devices and Integrated Magnetics

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1781 ◽  
Author(s):  
Yu-Chen Liu ◽  
Chen Chen ◽  
Kai-De Chen ◽  
Yong-Long Syu ◽  
Meng-Chi Tsai
Keyword(s):  
High Frequency ◽  
High Efficiency ◽  
Power Converter ◽  
Maximum Efficiency ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Leakage Inductance ◽  
Llc Resonant Converter ◽  
Resonant Inductor ◽  
Secondary Side

In this study, a light emitting diode (LED) driver containing an integrated transformer with adjustable leakage inductance in a high-frequency isolated LLC resonant converter was proposed as an LED lighting power converter. The primary- and secondary-side topological structures were analyzed from the perspectives of component loss and component stress, and a full-bridge structure was selected for both the primary- and secondary-side circuit architecture of the LLC resonant converter. Additionally, to achieve high power density and high efficiency, adjustable leakage inductance was achieved through an additional reluctance length, and the added resonant inductor was replaced with the transformer leakage inductance without increasing the amount of loss caused by the proximity effect. To optimize the transformer, the number of primary- and secondary-side windings that resulted in the lowest core loss and copper loss was selected, and the feasibility of the new core design was verified using ANSYS Maxwell software. Finally, this paper proposes an integrated transformer without any additional resonant inductor in the LLC resonant converter. Transformer loss is optimized by adjusting parameters of the core structure and the winding arrangement. An LLC resonant converter with a 400 V input voltage, 300 V output voltage, 1 kW output power, and 500 kHz switching frequency was created, and a maximum efficiency of 97.03% was achieved. The component with the highest temperature was the transformer winding, which reached 78.6 °C at full load.

scholarly journals Performances of Photovoltaic System Using Grid Tied Transformerless Inverter

2021 ◽  
pp. 287-292
Author(s):  
Ashish Raut ◽  
Sneha Tibude
Keyword(s):  
Leakage Current ◽  
Pulse Width Modulation ◽  
Neutral Line ◽  
Photovoltaic System ◽  
Pv Systems ◽  
Double Frequency ◽  
Power Switches ◽  
Dc Bus ◽  
Bus Voltage ◽  
Inverter Topology

In order to eliminate the common-mode (CM) leakage current in the transformer less photovoltaic (PV) systems, the concept of the virtual dc bus is proposed in this paper. By connecting the grid neutral line directly to the negative pole of the dc bus, the stray capacitance between the PV panels and the ground is bypassed. As a result, the CM ground leakage current can be suppressed completely. Meanwhile, the virtual dc bus is created to provide the negative voltage level for the negative ac grid current generation. Consequently, the required dc bus voltage is still the same as that of the full-bridge inverter. Based on this concept, a novel transformer less inverter topology is derived, in which the virtual dc bus is realized with the switched capacitor technology. It consists of only five power switches, two capacitors, and a single filter inductor. Therefore, the power electronics cost can be curtailed. This advanced topology can be modulated with the unipolar sinusoidal pulse width modulation (SPWM) and the double frequency SPWM to reduce the output current ripple. As a result, a smaller filter inductor can be used to reduce the size and magnetic losses.

scholarly journals Novel High-Efficiency High Step-Up DC–DC Converter with Soft Switching and Low Component Voltage Stress for Photovoltaic System

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1112
Author(s):  
Yu-En Wu ◽  
Jyun-Wei Wang
Keyword(s):  
High Voltage ◽  
Output Voltage ◽  
High Efficiency ◽  
Low Voltage ◽  
Leakage Inductance ◽  
Power Switch ◽  
Half Wave Voltage ◽  
Half Wave ◽  
Voltage Stress ◽  
Voltage Doubler

This study developed a novel, high-efficiency, high step-up DC–DC converter for photovoltaic (PV) systems. The converter can step-up the low output voltage of PV modules to the voltage level of the inverter and is used to feed into the grid. The converter can achieve a high step-up voltage through its architecture consisting of a three-winding coupled inductor common iron core on the low-voltage side and a half-wave voltage doubler circuit on the high-voltage side. The leakage inductance energy generated by the coupling inductor during the conversion process can be recovered by the capacitor on the low-voltage side to reduce the voltage surge on the power switch, which gives the power switch of the circuit a soft-switching effect. In addition, the half-wave voltage doubler circuit on the high-voltage side can recover the leakage inductance energy of the tertiary side and increase the output voltage. The advantages of the circuit are low loss, high efficiency, high conversion ratio, and low component voltage stress. Finally, a 500-W high step-up converter was experimentally tested to verify the feasibility and practicability of the proposed architecture. The results revealed that the highest efficiency of the circuit is 98%.

Development of Serial-Connected High Step-Up DC-DC Converter with Single Switch

2013 ◽  
Vol 479-480 ◽  
pp. 535-539
Author(s):  
Van Tsai Liu ◽  
Chien Hao Hsu
Keyword(s):  
Electric Vehicles ◽  
Pulse Width Modulation ◽  
Hybrid Electric Vehicles ◽  
Single Pulse ◽  
Input Voltage ◽  
Duty Ratio ◽  
Leakage Inductance ◽  
High Voltage Gain ◽  
Output Capacitor ◽  
Voltage Spike

In this paper, a novel high step-up DC-DC converter has been designed for fuel cell applications. The proposed high step-up converter can be used for various portable energy storage components such as fuel cells which are used for hybrid electric vehicles (HEV), and light electric vehicles (LEV).The proposed converter is integrated by boost circuit, voltage lift capacitor, and coupled-inductor techniques to achieve high step-up voltage and has several advantages. First, the circuit is controlled by one single pulse width modulation (PWM). Second, the converter consists of active clamp circuit to recycle the leakage inductance and send to output capacitor so that the voltage spike on active switch is suppressed and efficiency is also improved. Third, by using the winding of secondary boost circuit, and voltage lift capacitor techniques, the high voltage gain can be achieved without more than 50% duty ratio, and the slope compensation circuit can also be simplified.Finally, a 1k W prototype converter is implemented, to verify the performance of the proposed converter with input voltage 48V, output voltage 400V, and output power 1k W is also achieved. The highest efficiency is 92.96% at 400W, and the full-load efficiency is up to 90.48%.

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