Analysis and Output Voltage Control of a High-Efficiency Converter for DC Microgrids

Author(s):  
Mohammad Mousavi ◽  
Parisa M. Shabestari ◽  
Ali Mehrizi-Sani
Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1112
Author(s):  
Yu-En Wu ◽  
Jyun-Wei Wang

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%.


Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 117
Author(s):  
Yu-Kai Chen ◽  
Hong-Wen Hsu ◽  
Chau-Chung Song ◽  
Yu-Syun Chen

This paper proposes the design and implementation of inductor-inductor-capacitor (LLC) converters with modules connected in series with the power scan method and communication scan network (CSN) to achieve MPPT and regulate the output voltage for the PV micro-grid system. The Dc/Dc converters includes six isolated LLC modules in series to supply ±380 V output voltage and track the maximum power point of the PV system. The series LLC converters are adopted to achieve high efficiency and high flexibility for the PV micro-grid system. The proposed global maximum power scan technique is implemented to achieve global maximum power tracking by adjusting the switching frequency of the LLC converter. To improve the system flexibility and achieve system redundancy, module failure can be detected in real time with a communication scan network, and then the output voltage of other modules will be changed by adjusting the switching frequency to maintain the same voltage as before the failure. Additionally, the proposed communication scan network includes the RS-485 interface of the MPPT series module and the CAN BUS communication interface with other subsystems’ communication for the PV micro-grid application system. Finally, a 6 kW MPPT prototype with a communication scan network is implemented and the proposed control method is verified for the PV system.


Author(s):  
Fouad Farah ◽  
Mustapha El Alaoui ◽  
Abdelali El Boutahiri ◽  
Mounir Ouremchi ◽  
Karim El Khadiri ◽  
...  

In this paper, we aim to make a detailed study on the evaluation and the characteristics of the non-inverting buck–boost converter. In order to improve the behaviour of the buck-boost converter for the three operating modes, we propose an architecture based on peak current-control. Using a three modes selection circuit and a soft start circuit, this converter is able to expand the power conversion efficiency and reduce inrush current at the feedback loop. The proposed converter is designed to operate with a variable output voltage. In addition, we use LDMOS transistors with low on-resistance, which are adequate for HV applications. The obtained results show that the proposed buck-boost converter perform perfectly compared to others architecture and it is successfully implemented using 0.18 μm CMOS TSMC technology, with an output voltage regulated to 12V and input voltage range of 4-20 V. The power conversion efficiency for the three operating modes buck, boost and buck-boost are 97.6%, 96.3% and 95.5% respectively at load current of 4A.


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