http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters and generalized to any number of switches.<<ETX>>

Multi-level conversion : high voltage choppers and voltage-source inverters

In this paper, initially a new dc/dc converter is proposed which can produce boosted multiple dc link voltages by using the novel switched-capacitor converter (SCC) and with reduced number of switches. In the proposed SCC, voltage of all capacitors is charged by binary asymmetrical pattern as self-balancing and without using any auxiliary circuits. The proposed SCC will boost the input dc power supply voltage without transformer by switching the capacitors in series and in parallel. Next, a new single phase switched-capacitor multilevel inverter (SCMLI) topology which uses the proposed SCC units as virtual dc links have been proposed. The proposed topologies reduce the number of power switches, diodes, isolated dc power supplies, size, and the cost of the system in comparison with conventional similar topologies. For example, by contribution of proposed SCMLI structure, 49 and 137 output voltage levels are made by only 14 and18 power switches and 3 and 4 isolated dc power supplies, respectively. To confirm the performance of proposed topology, various simulation results by PSCAD/EMTDC software and experimental tests are given.

Generalized Structure for a Single Phase Switched-Capacitor Multilevel Inverter Using a New Multiple DC Link Producer With Reduced Number of Switches

Steady-state analysis of pulse-width modulated (PWM) Z-source dc-dc converter operating in continuous conduction mode (CCM) is presented. Voltage and current waveforms, and their corresponding expressions describing the steady-state operation of the PWM Z-source dc-dc converter have been presented. The input-to-output dc voltage transfer functions, both for ideal and non-ideal PWM Z-source dc-dc converter have been derived. The minimum Z-network inductance required to ensure CCM operation is derived. The voltage ripple due to filter capacitor and its ESR, and their individual effects on the the overall output voltage ripple have been derived and analyzed. Expressions for power loss in each of the components of the PWM Z-source dc-dc converter has been determined. Using the expressions derived to determine the power losses, an expression for the overall efficiency of the PWM Z-source dc-dc has been derived. An example PWM Z-source dc-dc converter is considered. A laboratory prototype is built and the theoretical analysis is in good agreement with the experimental results.

Analysis of PWM Z-Source DC-DC Converter in CCM for Steady State

Solar energy, at the present time is considered as an important source in electricity generation. Electricity from the solar energy can be generated using solar photovoltaic (PV) modules. The maximization of solar power extracted from a PV module is of special concern as its efficiency is very low. The output power of a PV module is highly dependent on the geographical location and weather conditions such as solar irradiation, shading and temperature. To obtain maximum power from PV module, photovoltaic power system usually requires maximum power point tracking (MPPT) controller. In this paper, an adaptive neuro-fuzzy inference system (ANFIS) based maximum power point tracker for PV module has been presented. To extract maximum power, a DC–DC boost converter is connected between the PV module and the load. The duty cycle of DC–DC boost converter is modified with the help of the ANFIS reference model, so that maximum power is transferred to load. Due to the complexity of the tracker mechanism and non-linear nature of photovoltaic system, the artificial intelligence based technique, especially the ANFIS method, is used in this paper. In order to observe the maximum available power of PV module, the ANFIS reference model directly takes in operating temperature and irradiance level as input. The response of proposed ANFIS based control system shows accuracy and fast response. The simulation result reveals that the maximum power point is tracked satisfactorily for varying irradiance and temperature of PV module. Simulation results are provided to validate the concept.

Modeling of solar PV module and maximum power point tracking using ANFIS

This article introduces a single-switch, high step-up, dc–dc converter based on coupled-inductor with three winding and voltage multiplier cell to obtain a very high-voltage conversion ratio. A passive clamp circuit is applied in the converter to recycle the energy of leakage inductance and reduce voltage stress of the main power switch. This leads to utilize a power switch with low on-state resistance and low voltage rating that decreases the conduction losses. Several advantages include low operating duty cycle, high voltage conversion ratio, low turn ratio of the coupled inductor, leakage inductance reverse recovery, reduced voltage stress of semiconductors, alleviation of diodes reverse recovery issue and high efficiency, which make the presented topology appropriate for sustainable energy applications such as photovoltaic systems. The operation principle and steady-state analysis of the suggested topology in continuous conduction mode are expressed in detail. Also, design procedure and theoretical efficiency analysis of the proposed topology are presented. Moreover, a comparison study is performed to demonstrate the superiority of the presented converter over several similar recently proposed dc–dc converters. Finally, the proposed dc–dc converter feasibility and performance are justified through a fabricated 216-W laboratory prototype at 50 kHz switching frequency.

A High Voltage Gain DC–DC Converter Based on Three Winding Coupled Inductor and Voltage Multiplier Cell

Hybrid energy harvesting system to maximize power generation from solar energy

In this study, a new non-isolated high step-up DC-DC converter is presented with high-voltage gain which is suitable for renewable applications. The proposed converter uses coupled inductor and voltage multiplier cell (diode capacitor) for increasing the voltage level. The voltage gain of the proposed converter can be increased by selecting the appropriate turns ratio of coupled inductor. Voltage multiplier cell consists of two diodes and two capacitors which are used to obtain high-voltage gain. The diode-capacitor cell is used as a clamp circuit, which leads to reducing the voltage stress across the semiconductors. The proposed converter has a single power switch which causes the control of the proposed converter is simple. Also, the power switch is used with lower ON-state resistant (
 R
 DS-ON
). The zero-current switching of the diode is obtained in OFF state. Therefore, the conduction losses are decreased with lower normalised voltage stress across semiconductors. To prove the performance of the proposed converter, theoretical analysis and comparison with other converters are provided. To confirm the benefits of the proposed converter, a laboratory prototype with 20 V input voltage, 200 V output voltage and about 200 W power level at operating 25 kHz is built and tested.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-pel.2018.5414

High step-up DC–DC converter with coupled inductor suitable for renewable applications

In this paper, using artificial neural network (ANN) for tracking of maximum power point is discussed. Error back propagation method is used in order to train neural network. Neural network has advantages of fast and precisely tracking of maximum power point. In this method neural network is used to specify the reference voltage of maximum power point under different atmospheric conditions. By properly controling of dc-dc boost converter, tracking of maximum power point is feasible. To verify theory analysis, simulation result is obtained by using MATLAB/SIMULINK.

https://downloads.hindawi.com/journals/mpe/2012/506709.pdf

PV Maximum Power-Point Tracking by Using Artificial Neural Network

This study proposes two configurations for a non-isolated, high step-up, single-switch, coupled-inductor-based DC–DC converter. A coupled inductor and voltage multiplier cells are used in the presented topologies to obtain a high voltage gain. Also, a passive clamp circuit is applied in the topologies to reduce voltage stress of the main power switch. This leads to utilising a power switch with lower on-state resistance, which decreases the conduction loss. Several advantages such as low operating duty cycle, high voltage conversion ratio, reduced voltage stress of semiconductors, low turn ratio of the coupled inductor, leakage inductance energy recovery and high efficiency operation make the presented structures appropriate for sustainable energy applications. The operational principle and steady-state analysis of the suggested topologies in continuous conduction mode are expressed in detail. Also, design procedure and theoretical efficiency of the topologies are presented. Then, the suggested topologies are compared with several similar high step-up topologies to prove their advantages. Finally, the performance and feasibility of the proposed DC–DC converter configurations are confirmed through experimental measurement results of 29 V input and 435 V/213 W and 480 V/238 W output laboratory prototypes at 50 kHz switching frequency.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-pel.2019.0139

Farzad Sedaghati

Papers

A High Voltage Gain DC–DC Converter Based on Three Winding Coupled Inductor and Voltage Multiplier Cell

Hybrid energy harvesting system to maximize power generation from solar energy

High step-up DC–DC converter with coupled inductor suitable for renewable applications

PV Maximum Power-Point Tracking by Using Artificial Neural Network

Two- and three-winding coupled-inductor-based high step-up DC–DC converters for sustainable energy applications