Design and implementation of an ultra-high voltage DC-DC converter based on coupled inductor with continuous input current for clean energy applications

In this paper, a novel non-isolated Single-Switch Quadratic Boost Coupled-Inductor (SSQBCI) DC/DC converter with continuous input current and low voltage stress on the switching component is presented. The suggested structure is based on the traditional quadratic boost converter. In this new topology, to achieve an ultra-high voltage gain without large duty cycle, a Coupled-Inductor (CI) along with a Voltage Multiplier (VM) are employed. The magnetic energy stored in the leakage inductor of the CI is recycled by a regenerative passive clamp capacitor that is connected with the switch in parallel, which helps to limit the maximum voltage across the switch. Therefore, to reduce the switch conduction loss and improve the efficiency, a switch with the low static drain-to-source ON-resistance can be used. Moreover, the low voltage stress on the output side diode alleviates the reverse recovery loss. The steady-state operating principle, comparisons with other related topologies and also design considerations in Continuous Conduction Mode (CCM) will be analyzed in detail. Finally, the performance of the proposed SSQBCI is verified by experimental results using a prototype with 30V input and 200V - 160 W output operation at a constant switching frequency 50 kHz.

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New Single-Switch quadratic boost DC/DC converter with Low voltage stress for renewable energy applications

This article introduces a new nonisolated full soft-switching step-up dc/dc converter based on single-ended primary inductor converter (SEPIC) structure. The proposed topology utilizes a three-winding coupled-inductor (TWCI) to increase the voltage gain, but unlike other coupled-inductor-based converters, its voltage gain is increased by reducing its magnetic turns ratio. Moreover, the secondary and tertiary turns ratios of the TWCI can be used as an additional design freedom to extend the voltage gain, which indicates more converter flexibility. Due to the continuous input current, the proposed converter can be used for many types of renewable energy sources. Also, the leakage energy from the TWCI has further been recycled and transferred to the output with the help of a regenerative passive clamp circuit. Due to the soft-switching performance, the proposed converter has no switching losses at the turn- on instant for the power switch and reverse recycling losses of the diodes. Furthermore, the use of a small number of components along with the soft-switching performance offer high efficiency. Steady-state analysis and design considerations are discussed thoroughly. Finally, a 200-W prototype with 200 V output voltage is provided to verify the theoretical analysis.

Analysis of a New Soft-Switched Step-Up Trans-Inverse DC/DC Converter Based on Three-Winding Coupled-Inductor

This study proposes a new structure of hybrid cascade coupled-inductor high step-up (HCCIHSU) DC/DC converter for renewable energy sources. The proposed topology can provide an ultra-high voltage gain under continuous input current and low voltage stress on semiconductor devices. This converter is a hybrid cascade connection of the boost and buck–boost converters. The HCCIHSU utilises a coupled-inductor (CI) and a voltage multiplier (VM) cell to enhance the voltage gain ratio as a semi-quadratic function. The magnetic energy of the leakage inductor of the CI is recycled to the VM capacitors that reduce the component voltage stress and improve the converter voltage gain. Additionally, the voltage stress on the main power switch is clamped by two passive clamp capacitors. Due to the very high voltage conversion ratio at a reduced turn's ratio, the maximum voltage stresses on the switches and diodes are significantly alleviated, which further improve the efficiency. In this study, detailed steady-state analysis and comparisons with other related converters are provided. Finally, a 160 W/200 V laboratory prototype is built with 24 V input voltage at a switching frequency of 50 kHz to verify the performance of the proposed converter.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-pel.2020.0544

Hybrid cascaded high step-up DC/DC converter with continuous input current for renewable energy applications

This study proposes a high step-up DC–DC converter which is composed of a conventional quadratic boost converter, a switched capacitor and a coupled inductor. To reduce the number of components, the primary side of the coupled inductor is shared with the quadratic boost converter as one of its inductors. Furthermore, the output capacitor of the quadratic boost converter is divided into two capacitors and one of them is utilised in common with the switched capacitor. The converter is analysed and the obtained equations are used to compare the proposed converter with other converters which have similar structures. According to the comparisons, the proposed converter has advantages such as higher voltage gain, the lower voltage stress on the power switch and requiring a smaller inductor. In addition, the input source current is continuous and there is a common ground between the source and load. Increasing the turn ratio of the coupled inductor causes reduction of voltage stress on the power switch, diodes and capacitors. To investigate performance of the proposed converter, an 80 W prototype is built. The experiments show good accordance with the analysis and they demonstrate the high step-up capability of the proposed converter.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-pel.2020.0044

High step-up DC–DC converter composed of quadratic boost converter and switched capacitor

In this article, a novel coupled inductor-based high step-up dc–dc converter is proposed. The introduced converter benefits from various advantages, namely ultrahigh voltage gain, low voltage stress on the power switches, and continuous input current with low ripple. Therefore, the presented converter is suitable for renewable energy applications. By utilizing clamped circuit, voltage spike of the active switch is clamped during the turn- off process. Hence, a switch with low $R_{\text{DS-on}}$ can be used, which reduces the conduction losses as well as the cost of the converter. Furthermore, the energy of leakage inductance is used to obtain zero voltage switching (ZVS) for the main and auxiliary switches. Additionally, the output diode current falling rate is controlled by leakage inductance; thus, reverse-recovery problem of output diode is alleviated. The steady-state analysis and design considerations of the proposed converter are discussed. Finally, a 250-W experimental prototype of the presented converter is implemented to validate the converter operation and the theoretical analysis.

Coupled Inductor-Based High Voltage Gain DC–DC Converter For Renewable Energy Applications

Single switch quadratic boost converter with continuous input current for high voltage applications

This paper precisely investigates pulse width‐amplitude modulation approach in quasi‐Z‐source inverters It will be concluded that using this method in such converters causes two undesired behaviors A general solution is proposed for solving the problems regarding the use of PWAM in such inverters and then simulation and experimental results are presented in order to confirm the study

Performance improvement of pulse width‐amplitude modulation‐based quasi‐Z‐source inverters: Analysis and implementation

A quasi‐Z‐source inverter with a single high‐frequency‐switch

In recent years, the penetration of distribution generations (DGs) has increased. Also the role of distributed generation has significantly increased not only as power generator, but also as an important factor in power quality improvement. In this paper, a method is proposed for reducing the voltage unbalance while the DG is not connected to the grid. Control loops pertaining to voltage and frequency powers are provided in order to control the voltage and frequency of local load. Besides, the virtual impedance loop and proportional-resonant controller are also utilized in the control loop. The simulation results confirm the functionality of the control strategy and the controllers in eliminating the imbalance.

Afshin Mirzaee

Papers

Coupled Inductor-Based High Voltage Gain DC–DC Converter For Renewable Energy Applications

Single switch quadratic boost converter with continuous input current for high voltage applications

Performance improvement of pulse width‐amplitude modulation‐based quasi‐Z‐source inverters: Analysis and implementation

A quasi‐Z‐source inverter with a single high‐frequency‐switch

Power quality enhancement in islanded microgrid