Three-level Boost Converter Research Articles

An efficient implementation of three-level boost converter with capacitor voltage balancing for an advanced MPPT approach in PV Systems

Ensuring optimal extraction of power from photovoltaic (PV) systems under diverse climatic circumstances is a significant challenge, which requires an efficient Maximum Power Point (MPP) Tracking (MPPT) algorithm and an adequate conversion stage. Therefore, this paper proposes an advanced MPPT strategy implemented by a Three-Level Boost converter (TLB), which serves as the interface between the PV generator and the DC load, offering advantages such as reduced output voltage distortion, minimized inductor current ripple, and decreased switching losses. To achieve more accurate tracking, a robust voltage balance control across the TLB converter capacitors is also suggested. The proposed system is meticulously implemented and evaluated using MATLAB/Simulink, demonstrating its robust control capabilities in MPP tracking and voltage balancing across the TLB converter capacitors under diverse climatic scenarios. Furthermore, comparative analysis under various test circumstances including static and dynamic insolation conditions and sudden load variations, shows that the suggested MPPT algorithm offers noteworthy improvements over the InC algorithm. Additionally, a thorough comparison with existing research methods proves its effectiveness over these methods. The advanced MPPT strategy achieves a steady-state error of 0 W, an average tracking efficiency between 99.13 % and 99.44%, and fast-tracking velocity. Further, a comprehensive real-time evaluation using the cutting-edge RT-LAB platform confirms the consistency of the results with the simulation outputs, emphasizing the robustness and low implementation complexity of the overall proposed control strategy.

A 96.3%-Efficiency Wide-Voltage-Range Three-Level Boost Converter With Loop-Free Self-Balancing and Dead-Zone PWM Control for Backlight LED Drivers

A 96.3%-Efficiency Wide-Voltage-Range Three-Level Boost Converter With Loop-Free Self-Balancing and Dead-Zone PWM Control for Backlight LED Drivers

Adaptive nonlinear control of the Single-Phase Grid-Connected Photovoltaic System

This paper addresses the problem of controlling the single-phase grid connected to the photovoltaic (PV) system through a three-level boost converter (TLBC) and half-bridge inverter (HBI) with LCL-filter. This study aims to achieve four main objectives: (i) ensure that the output voltage of PV panel track a reference given by the MPPT block based on the perturb and observe (P&O) algorithm; (ii) regulate DC bus voltage to ensure injection of photovoltaic power into the grid; (iii) guarantee power factor correction (PFC); (iv) ensure a balance between TLBC output voltages. The problem is dealt with using a nonlinear controller based on the backstepping and lyapunov approaches, a filtered-PI regulator to ensure the power balance between the grid and the PV panel. An adaptive observer is designed in order to estimate the voltage and the impedance parameters of power grid, by measuring only the grid current. The proposed controller and observer performances are confirmed by simulation in MATLAB\\Simulink.

A Three-Level Boost Converter With Fully State-Based Phase Selection Technique for High-Speed VCF Calibration and Smooth Mode Transition

A Three-Level Boost Converter With Fully State-Based Phase Selection Technique for High-Speed V_CF Calibration and Smooth Mode Transition

Optimized Modulation Method for Three-Level Boost Converter With ZVS Under Unbalanced-Load Operation

Optimized Modulation Method for Three-Level Boost Converter With ZVS Under Unbalanced-Load Operation

Unified Modeling and Double-Loop Controller Design of Three-Level Boost Converter

A new small-signal modeling of a three-level boost (TLB) converter, as well as the design methodology for a double-loop controller, are presented in this paper. Unlike the conventional modeling of the TLB converter, which involves three state variables, the suggested modeling is based on two state variables; hence, simple transfer functions can be obtained. The proposed method is operable at a full duty ratio using unified modeling approaches, regardless of the mode changes. The analysis shows that the transfer functions of the two operation modes are identical. This suggests that the small-signal modeling of the TLB converter is identical to that of a conventional single-level boost converter. Hence, this implies that a linear feedback controller is applicable for all operational ranges. The method to design a double-loop controller using a proportional-integral controller is shown in a stepwise sequence. In addition, a capacitor voltage unbalancing controller is described. Simulations and experimental verifications are conducted to verify the effectiveness of the small-signal analysis and control system design.

Maximum Power Point Tracking Performance Benchmarking of High Step-Up DC-DC Converters

Since renewable energy sources (RESs) such as photovoltaic (PV) and wind energy have low output voltage and intermittent output power, they are frequently equipped with step-up DC-DC converters to boost the output voltage and extract maximum power. In this study, maximum power point tracking (MPPT) performance comparisons of high voltage gain DC-DC converters, which are frequently used in PV-powered systems, have been presented. Three different high gain step-up DC-DC converter topologies: (i) quadratic boost converter (QBC), (ii) three level boost converter (TLBC), (iii) stacked boost converter (SBC) have been analysed under MPPT mode that uses the Perturb and Observe (P&O) algorithm. 5.11 kW PV-powered system has been modelled in the MATLAB/Simulink environment for each converter considering the same design specifications such as; 10 kHz switching frequency, 1 mΩ Ron resistance. The related topologies have been simulated under different irradiances: 1000, 900, 850, 750 and 700. Performance results of the aforementioned topologies have been compared in terms of the maximum power of PV panel, the energy efficiency of converters, output voltage ripple and output current ripple. The results reveal that; the TLBC extracts maximum power from PV panels with the converter efficiency 98.9%. The SBC and QBC extract minimum power from PV panels with the converter efficiency 98.1% and 96.5%, respectively. As a consequence, TLBC topology excels with the maximum power extraction capability and efficiency.

New Configuration of Five-Level NPC Inverter with Three-Level Boost Converter for Photovoltaic Solar Energy Conversion

This paper deals with the modeling and control of a new two-stage photovoltaic conversion cascade composed of a Three-Level Boost (3LB) converter and a three-phase NPC five-level inverter (5LI). The main objective is to ensure the continuity of energy transfer from a renewable continuous source to the electrical grid while regulating the voltages of the DC bus capacitors with a new proposed configuration. The 3LB is controlled in MPPT based on fuzzy logic. A PI regulator is introduced into the 3LB regulation loop in order to maintain the equality of the two output voltages. The overall voltage of the DC bus being regulated by the control of the multilevel inverter interconnected to the grid, using synchronous reference frame control. Therefore, in our case there is the problem of voltages imbalance caused by the 5LI. We propose in this work to introduce two Clamping Bridges (CBs) each one is composed by a transistor in series with a resistor. These CBs are introduced in parallel with two capacitors of the DC bus. This solution avoids us to use the control algorithm by redundant configurations in the regulation loop of the 5LI. The results obtained show the effectiveness of the proposed control in stabilizing and maintaining the four DC bus voltages at equal values. With four balanced capacitor voltages, we get symmetrical inverter output voltage waveforms, which directly affects the quality of the current injected to the grid.

Fuzzy and predictive control of a photovoltaic pumping system based on three-level boost converter

In this work, an efficient control scheme for a double stage pumping system is proposed. On the DC side, a three-level boost converter is employed to maximize the photovoltaic power and to step-up the DC-link voltage. For maximum power point tracking, the classical incremental conductance method is substituted by a fuzzy logic controller. The designed controller estimates the optimal step size which speeds up the tracking process and improves the accuracy of the extracted photovoltaic power. Afterwards, the voltages across the three-level boost converter (TLBC) capacitors are balanced by phase shifting the applied duty ratios. On the motor pump side, a two-level inverter drives the motor pump with the cascaded nonlinear predictive control. The predictive controller is preferred over the conventional field-oriented control because it accelerates the torque response and resists to the change of the engine parameters. The designed controllers are evaluated using MATLAB/Simulink, and compared with the conventional controllers (incremental conductance algorithm and field-oriented control). The robust control scheme of the entire system has increased the hydraulic power by up to 23% during the system start-up and up to 10% in steady state.

Intelligent Perturb and Observe Based MPPT Approach Using Multilevel DC-DC Converter to Improve PV Production System

In this paper, an optimized maximum power point tracking (MPPT) control for a standalone photovoltaic (PV) system using a three-level boost (TLB) converter is introduced. The proposed MPPT method is based on an intelligent perturb and observe algorithm using the artificial neural network (ANN-P&O) to reduce the oscillations at the maximum power point (MPP). In advance, The ANN provides the values of the voltage and the current at the MPP for any solar irradiance and cell temperature. Based on the provided voltage and current, the P&O algorithm generates the optimal duty cycle of the TLB converter to perfectly track the MPP of the PV generator for different values of cell temperature and sunlight irradiance. Besides, a proportional-integral (PI) controller is added to ensure the TLB capacitor voltage balance. The established ANN-P&O approach is validated in Matlab/Simulink and compared to the conventional P&O algorithm under various scenarios: (i) irradiance variations, (ii) temperature variations, and (iii) load variations.

Design of double loop controller for three-level boost converter

Three-level Boost Converter (TLBC) is widely used in new energy generation grid-connected technology. This topology not only reduces the voltage stress of the switching tube and the diode, but also has a smaller size, lighter weight and higher power density. However, it has the problem of midpoint potential shift. In this paper, a dual closed-loop controller is designed by establishing the AC small-signal model of the system. while stabilizing the output voltage, the upper and lower capacitor voltages are dynamically adjusted to ensure the balance of the midpoint potential. Finally, this paper establishes a simulation platform in MATLAB/Simulink and verifies the dual-loop controller scheme.

Experimental evaluation of direct torque-controlled 3-phase induction motor under inverter faults

ABSTRACTIn this paper, analysis and design of fault-tolerant converter topology for direct torque-controlled (DTC) induction motor (IM) drive suitable for low, medium and high power applications is proposed. The proposed converter topology can restore normal operation of the drive after the occurrence of open-circuit or short-circuit of power switches in the inverter. It consists of a current-controlled three-level boost converter (TLBC) to boost the dc-link voltage at input terminals of an inverter during post-fault, balance the voltages at dc-link capacitors and retains all the advantages of the conventional IM drive. Simulation and experimental results are presented for pre- and post-fault operation. The results are compared with conventional fault-tolerant DTC of the drive to highlight the merits of proposed converter.

An Efficient Control Scheme of Self-Reliant Solar-Powered Water Pumping System Using a Three-Level DC–DC Converter

This article proposes a reliable and cost-effective solution of water pumping system for the off-grid community, where the grid supply is not available. The designed system uses an 8/6 pole, four-phase switched reluctance motor (SRM) with a midpoint converter as a drive to pump the water. A three-level boost converter (TLBC) is used as an intermediate power conversion stage between the solar photovoltaic (PV) array and motor-pump. The TLBC has many benefits such as low voltage stress across devices, small inductor size, and ability to operate with a wide voltage range, which make the proposed system highly efficient and cost-effective. An efficient control technique is developed for the designed system, which simultaneously maximizes the PV array power and equalizes the voltages across split capacitors of a midpoint converter under all working conditions. An online flux optimization with a single-pulse mode of the SRM drive is developed and implemented. The developed control scheme eliminates the need of any phase current sensor, and the motor speed is fully governed by the available PV array power. This article proposes a new technique to emulate the characteristics of centrifugal water pump using a dc generator. This technique provides a simple solution to test the centrifugal solar pumps in the laboratory. The system under study is simulated in MATLAB/Simulink, and its different responses are examined under all possible working conditions. The simulated results are authenticated by the test results obtained through a developed prototype in the laboratory.

Sensorless second-order switching surface for a three-level boost converter

This paper proposes a sensorless second-order switching surface to control a three-level boost converter (TLBC). A predictive current method is proposed to reduce the number of sensors in the normal second-order switching surface method. Based on a developed model of the TLBC, the current is estimated and a switching surface is formulated in the state-energy plane. Simulation and hardware tests are carried out to verify the viability and the effectiveness of the proposed control technique. Results obtained show a good performance of the converter in term of DC-bus balancing and fast dynamic response under sudden load change.

Balance Midpoint Potential Control of Three-Level Boost Converter for Rail Transit Application

The application of the three-level boost converter (TLBC) in a high-frequency isolated auxiliary inverter system is able to reduce the voltage stress of power switches and diodes in the back-end circuit, reduce the volume and weight of energy storage components, and improve the overall power density of the converter system. However, the TLBC topology has its own disadvantage which is the capacitor midpoint potential offset problem. In order to solve this problem, this paper analyzes the limitations of the traditional independent duty control strategy first and then proposes the pulse phase delay control strategy to balance the midpoint potential of TLBC. After the relevant theoretical analysis based on the ac small-signal model of the TLBC, which is controlled by the pulse phase delay control strategy, this paper completes its modeling and simulation by using PSIM & Matlab. Finally, this paper presents some experimental results and combines with the waveforms of the simulation to verify that the proposed control strategy can effectively adjust the bias voltage without changing the TLBC output characteristics.

FPGA Implementation of a Three-Level Boost Converter-fed Seven-Level DC-Link Cascade H-Bridge inverter for Photovoltaic Applications

This paper presents an optimized single-phase three-level boost DC-link cascade H-bridge multilevel inverter (TLBDCLCHB MLI) system to generate a seven-level stepped output voltage waveform for photovoltaic (PV) applications. The proposed TLBDCLCHB MLI system is obtained by integrating a three-level boost converter (TLBC) with a seven-level DC-link cascade H-bridge (DCLCHB) inverter. It consists of a TLBC, level generation unit (LGU) and phase sequence generation unit (PSGU). When compared with traditional boost converter-fed multilevel inverter systems, the proposed TLBDCLCHB MLI system requires a single DC source, fewer power switches and gate drivers. Reduction in the switch count and number of DC sources makes the system cost effective and requires a smaller installation area. Pulse generation for the power switches of an LGU in a DCLCHB inverter is accomplished by providing proper conducting angles that are generated by optimized conducting angle determination (CAD) techniques. In this paper two CAD techniques i.e., equal-phase CAD (EPCAD) and step pulse wave CAD (SPWCAD) techniques are proposed to evaluate the performance of the proposed system in terms of the total harmonic distortion (THD) and the quality of the stepped output voltage waveform. The proposed system has been modeled and simulated using MATLAB/SIMULINK software. Results are presented and discussed. Also, a prototype model of a single-phase TLBDCLCHB MLI system is developed using a field-programmable gate array (FPGA)-based pulse generation with a resistive load and its performance is analyzed for various operating conditions.

Reducing Cost and Size in Photovoltaic Systems Using Three-Level Boost Converter Based on Fuzzy Logic Controller

Photovoltaic (PV) systems are dependent on two main factors of temperature and solar radiation, changing the PV system into a nonlinear system. Therefore, it is necessary to propose an intelligent control system for power control of PV systems to tackle this issue. So, a three-level boost converter (TLBC) based on the maximum power point tracking (MPPT) with fuzzy intelligent control is suggested to solve the problems. In this paper, instead of using the conventional boost converter, TLBC is used. However, the conventional boost converter is typically used in PV systems as the interface between the PV panel and the consumer. TLBC has a lower weight and cost than the conventional boost converter. In addition, the main scope of this paper is reducing the system weight and employing TLBC with MPPT for controlling the output power without any fluctuations. In addition, the MPPT controller for TLBC is developed based on fuzzy logic and is compared with perturb and observe (P&O) algorithm, proportional–integral (PI) controller, particle swarm optimization (PSO) algorithm, and hybrid simplified accelerated particle swarm optimization (HSAPSO) algorithm. Using fuzzy logic controller (FLC), the value of MPP is tracked suitably under different climatic conditions as well as different temperatures and radiation, where TLBC passes the energy from a PV panel to the output in a high-speed and free-oscillation manner. Furthermore, balancing the voltage of TLBC capacitors with the proportional controller (P) is done due to their non-equivalent series resistance. The simulation results in MATLAB suggest the accuracy and performance of the system.

Modelling and Control Design for Energy Management of Grid Connected Hybrid PV-wind System

<p class="MsoNormal" style="margin-right: -14.15pt; text-align: justify; text-justify: inter-ideograph;">This paper deals with the control of hybrid PV-WIND power conversion structure. This paper develops a very important contribution which is the use of a single DC to DC converter, linearization of control of the three- level boost converter (TLBC) considering the imperfections of the passive components. The (TLBC) control provides balancing of capacitor voltages and maximum power operation of PV generator. For reasons of simplicity, a linearization based on the dynamic compensation of the disturbance is proposed. A sensorless maximum power point tracking (MPPT) algorithm is used to maximize a power extracted of the wind generator. The proportional relation between the rotational speed and the output voltage of the rectifier allows to use a voltage sensor to estimate the DC bus voltage reference instead of a mechanical speed sensor. The control of the three-phase inverter allows a transfer of the active power, the power factor close to the unit and thus a limitation of the reactive power injected into the grid. The external control loop performs the regulation of the common DC bus voltage while the internal control loop regulates the dq components of the currents injected into the grid. The simulation results showed the validity of the control approach. The proposed power conversion structure based on a single static converter has shown very good performance in terms of efficiency, the quality of the energy produced, complementarity between the two renewable sources and reliability. The paper ends with conclusions.</p>

A Novel Hybrid DC Traction Power Supply System Integrating PV and Reversible Converters

A novel hybrid traction power supply system (HTPSS) integrating PV and reversible converter (RC) is proposed. PV is introduced to reduce the energy cost and increase the reliability of power systems. A reversible converter can achieve multiple objectives including regenerative braking energy recovery, PV energy inverting, DC voltage regulation and power factor improvement. In this paper, the topology and operating modes of the HTPSS are first introduced. Three-level boost converter (TLBC) is employed in the PV system. A double closed-loop control scheme considering both maximum power point tracking (MPPT) and midpoint potential balancing (MPB) is recommended. The reversible converter adopts a multi-modular topology and the independent control for active power and reactive power has been achieved by a current decoupling control. According to the working characteristic of each device, a coordinated control strategy is designed, and four basic principles are given. A system simulation model containing a hybrid traction substation and a train was built, and comprehensive simulations under multi-scenario were carried out. The results show that the reversible converter can accomplish PV energy inversion, DC voltage regulation, regenerative braking energy recovery and power factor improvement, by which a high utilization rate and energy-saving effect can be obtained.

Maximum power point tracking techniques for wind energy systems using three levels boost converter

This paper presents modeling and simulation of three level Boost DC-DC converter in Wind Energy Conversion System (WECS). Three-level Boost converter has significant advantage compared to conventional Boost. A maximum power point tracking (MPPT) method for a variable speed wind turbine using permanent magnet synchronous generator (PMSG) is also presented. Simulation of three-level Boost converter topology with Perturb and Observe algorithm and Fuzzy Logic Control is implemented in MATLAB/SIMULINK. Results of this simulation show that the system with MPPT using fuzzy logic controller has better performance to the Perturb and Observe algorithm: fast response under changing conditions and small oscillation.