3-level NPC Inverter Research Articles

ADRC-LSE Control of a Dual-Star Induction Motor Powered by a Dual 3-level NPC Inverter

In the context of electric vehicle propulsion drives, this paper presents anActive disturbances Rejection Control (ADRC) strategyapplied to a Dual Star Induction Motor (DSIM)powered by dual 3 levels inverter type NPC. The proposed method focuses on enhancing the Active Disturbance Rejection Control (ADRC) method by integrating Least Squares Estimation, establishing a direct relationship between the control law and the necessary frequency for the DSIM to turn in the exact speed whatever the load torque applied. The ADRC with Least Squares Estimation is compared with Field-Oriented Control (FOC) to evaluate their performance in tracking reference speed and stabilizing time. Additionally, another test is conducted to assess the ADRC's ability to reject disturbances. Results from the simulation demonstrate the effectiveness of ADRC with Least Squares Estimation, showcasing its potential for optimizing DSIM control in electric vehicle applications, thereby contributing to enhanced efficiency and stability.

공통 모드 전압 및 THD를 고려한 계통연계형 3레벨 NPC 인버터의 운용 알고리즘 연구

A grid-connected 3-level NPC inverter is a power conversion device that connects renewable energy generators, such as photovoltaic or wind turbines to the grid. Although many studies have focused on this inverter, commercializing it requires strictly satisfying various safety and power quality-related standards. Among many standards, leakage current and grid current total harmonic distortion(THD) can be affected by external factors such as installation environment, aging, and grid conditions. Hence, inverter operations that can satisfy these standards need to be explored. In this study a 3-level NPC inverter operation algorithm using the Phase Opposition Disposition-PWM method that can effectively reduce leakage current and switching frequency adjustment to reduce THD effectively has been proposed.

Virtual Space Vector Pulse Width Modulation for Asymmetric T-Type Neutral Point Clamped 3-Level Inverter

This paper proposes a novel 3-phase asymmetric 3-level T-type NPC inverter and studies its PWM performance using a virtual space vector pulse width modulation control strategy. Firstly, the mathematical model and characteristics of this economical topology are described. Then, a virtual space vector approach is proposed to build a space vector diagram for designing SVPWM control. Similar to the conventional 3-level NPC inverter, the asymmetric inverter can also work with the neutral point voltage self-balancing in a fundamental period, which enables employment of this topology in various applications. Finally, simulation and experiment results under different load conditions have shown good output performance of the asymmetric 3-level topology. Similar tests are also performed on both conventional 2-level and 3-level inverters for comparison. For an almost similar number of different voltage vectors in the space vector diagram, the asymmetric 3-level topology can compete with conventional 3-level inverters for low-cost applications. The obvious benefit of the asymmetric 3-level inverter is a smaller number of switches devices while it can achieve output performance similar to that of the conventional 3-level. The comparative investigation also shows that the total loss given by SVPWM for the asymmetric 3-level configuration is lower than that of the traditional 3-level inverter.

Design and Implementation of Multilevel Inverter with Various MPPT Algorithms for Optimal Tracking of PV System

In this paper the different algorithm is performed in MATLAB Simulink to extract large amounts of energy from the pv system. MPPT algorithm is used to reduce complexity and to get better results, we used to perturb and observation, incremental conductance and fuzzy logic algorithm. A three-phase NPC inverter is used to connect the PV array with grid system, The PWM control method is used for the producing the PWM inverter signals. it contains PV array, dc / dc boost, three level NPC inverter. To get the synchronization between PV system and grid the synchronous reference frame theory with PLL block is used. The SRF theory will transform the three phase load currents (ia, ib, ic) to the two instantaneous active (id) and reactive (iq) components. The MATLAB simulation is preformed and we get a constant high output voltage from low input voltage and by changing the irradiance and temperature.

Reactive Power Control and Neutral Current Elimination of Four Wire Five Level NPC Inverter based STATCOM using 3D-SVPWM Technique

In this paper, three phase four wire five level Neutral Point Clamped Inverter (NPCI) based Static synchronous Compensator (STATCOM) is implemented for reactive power control and neutral current elimination. Three dimensional Space Vector Pulse Width Modulation (3D-SVPWM) control strategy is developed to control this 5-level NPC inverter. The behaviour of static synchronous compensator is analyzed and reactive power control is done using constant DC voltage. The objective of this compensating method is to provide balanced and sinusoidal source currents under unbalanced and nonlinear load conditions and reactive power control. The 3D-SVPWM technique provides reduced harmonic content in output voltage and current, controlled source current, minimized common mode voltage and improved output voltage. In 3D-SVPWM, switching pulses are generated with non-redundant switching states, which lead to reduce the complexity in switching time calculation and computational time is less. The highlights of the paper includes the neutral current is reduced to 0.25A, source current harmonics is minimized and it provides balanced and sinusoidal source currents with help of STATCOM compensation. The simulation and experimental results demonstrates the sinusoidal and harmonics free source current and minimized neutral current for four wire five level NPCI based STATCOM.

A Single Z-Source Network-Based 3-Level NPC Inverter Using a Novel Region Selection Approach of SVM

This paper aims to explain that a Z source network-based single-stage multilevel inverter topology provides better capability in terms of cost, component, and losses compared to conventional voltage-buck and voltage-boost. Only a limited amount of literature is currently available on a single LC network-based 3-level inverter employing space vector modulation. To define it, space vector modulation is an advanced computational Pulse Width Modulation (PWM) technique where the revolving space vector is used as a reference to generate pulses. Keeping that in mind, a novel Space vector modulation for a single LC network-based 3-level inverter has been implemented in this paper. The proposed SVM algorithm exhibits better quality output voltage compared to the previously reported single LC-based 3-level inverter. The effectiveness of the proposed algorithm is verified through extensive simulation study on a 3-level NPC inverter topology. This simulation is developed in a MATLAB/SIMULINK environment with an R-L load. The performance of the inverter is appositely investigated in terms of harmonics, capacitor voltage, inverter output voltage, and current. The proposed model encounters its application in fuel cell-based electric vehicles.

New model of electric traction drive based sliding mode controller in field-oriented control of induction motor fed by multilevel inverter

This paper presents a new model of electric traction drive for electric vehicle. The sliding mode speed controller applied in the Indirect Rotor Field Oriented Control is used to control the induction motor fed by the five levels Neutral Point Clamped inverter (NPC). The simulation results showed the high performances dynamics and high robustness of the proposed model, that are reflected by faster startup and good speed tracking performances in terms of response time, oscillations and disturbance rejection. Also, a comparative study between different inverter topologies: two levels inverter, three levels NPC inverter and five levels NPC inverter has been carried out. From the spectral analysis, the five-levels NPC inverter fed drive provides better dynamics of voltage and current with reduced total harmonic distortion (THD).

PWM control techniques for three phase three level inverter drives

In this paper two very efficient pulse width modulation techniques were discussed named Sin pulse width modulation and space vector pulse width modulation. The basic structure of the three-level inverter neutral-point clamped is introduced and the basic idea about space vector pulse width modulation for three-level voltage source inverter has been discussed in detail. Nearest three vectors space vector pulse width modulation control algorithm is adopted as the control strategy for the three phase three level NPC inverter in order to compensate the neutral-point shifting. Mathematical formulation for calculating switching sequence has determined. Comparative analysis proving superiority of the space vector pulse width modulation technique over the conventional pulse width modulation, and the results of the simulations of inverter confirm the feasibility and advantage of the space vector pulse width modulation strategy over sin pulse width modulation in terms of good utilization of dc-bus voltage, low current ripple and reduced switching frequency. Space vector pulse width modulation provides advantages better fundamental output voltage and useful in improving harmonic performance and reducing total harmonic distortion.

BEHAVIOR OF A SIX PHASE INDUCTION MOTOR FED BY MULTILEVEL INVERTER

The study of the behavioural analysis of the dual star induction machine fed by voltage inverters is presented in this article. One of the drawbacks of the DSIM supply via PWM voltage inverters is the occurrence of harmonic currents circulating large amplitude; these late induce leaking in the machine due to the chopping frequency of the inverter. Based on advanced dynamical model and equivalent circuit of DSIM developed in this paper, the study and the analysis of the DSIM fed by PWM inverter is done. The impact of the increase in levels of the voltage inverter controlled with natural PWM is studied. Minimisation of the circulating currents between two stars with the technique of space vector PWM is analysed, using the SVPWM simplify of three level NPC inverter will relieve the simulation and thereby obtain the effect of this technique on torque ripples and quality of energy in the machine.

Simulation of Zeta Converter Based 3-level NPC Inverter with PV System

<span lang="EN-US">This paper proposes increasing the efficiency of the autonomous Photovoltaic (PV) system by utilizing zeta converter alongside neutral point clamped multilevel inverters (NPC-MLI) based on innovative PWM scheme. The PV system acts as an input source and the relevant control of zeta converter through maximum power point tracking (MPPT) offers the maximum available power from the PV array connected to DC-link. To obtain a high voltage gain we need to exhaust the dc-link voltage as much as possible and reduce stress on the switches. For this the NPC-MLI algorithm approaches PWM technique to perform capacitive charging in parallel and discharging in series to obtain maximum voltage gain. The proposed scheme is designed and verified via detailed simulations in the MATLAB/Simulink environment. </span>

Design and Simulation of Three Level Neutral Point Clamped Inverter Fed Induction Motor Drive

The objective of the project is to obtain some proficiency in building converters to control speed of medium voltage induction motors. The thesis covers summary of literature surveyed, selection of a topology of converter for design, design of a 3-Level NPC inverter power circuit and FOC parameters. The entire system has been simulated using PSIM software for verification of design. Results obtained are presented. Results prove that the understanding of the student (author) is satisfactory. A low voltage 10kW squirrel cage induction motor has been chosen as the load to converter for design and simulation. Future work may be design of complete control circuits implementing FOC, building complete hardware and testing the small motor chosen.

Nonlinear control of a grid connected hybrid energetic systems (HES) based on photovoltaic- fuel cells distributed power generation systems

This paper presents a discrete-time integral sliding mode control for a grid connectedhybrid energetic systems (HES) based on photovoltaic-Solid oxide fuel cell (SOFC) for distributedpower generation systems. The proposed HES systems employ solid oxide fuel cell (SOFC) andphotovoltaic panels as main sources, supercapacitors as complementary sources, and controlledDC-DC boost converter and three levels NPC inverter. A maximum power point tracking (MPPT)control is used in order to maximize the power of the photovoltaic system. The proposed controlconsists of a power management grid interface inverter transferring the energy from the hybridsources into the grid by controlling the main utility grid and the common DC voltage active andreactive power. The obtained simulation results show the effectiveness and robustness of theproposed control strategy. Keywords: Hybrid Energetic Systems (HES), Solid Oxide Fuel Cell (SOFC),Photovoltaic (PV), Sliding Mode Control, Maximum Power Point Tracking (MPPT), Grid powermanagement.

A Novel SVPWM Algorithm Considering Neutral - Point Potential Balancing for Three - Level NPC Inverter

For three-level inverter, complexity of control strategy and neutral-point potential imbalance problem of DC side is the bottleneck restricting its application. In order to solve the problem, a simplified implementation of three- level space vector pulse width modulation (SVPWM) considering neutral-point potential balancing is proposed in this paper. The proposed SVPWM algorithm is based on judging of three phase voltages and voltage-second balance principle, which does not need to perform the sine and cosine c alculations, and thus it is more convenient and effective than traditional SVPWM algorithm. Also, the neutral-point potential balancing can be realized conveniently and effectively. The proposed algorithm can not only effectively simplify the calculation and reduce calculation time greatly, but also achieve the same control effect as traditional SVPWM. It has certain reference significance and can be used to shorten sampling time and improve the inverter performance. Finally, the proposed SVPWM algorithm is verified by simulation and experimental results.

Three Level Neutral Point Clamped Inverter Using Space Vector Modulation with Proportional Resonant Controller

Abstract Renewable energy is spreading in various format of supplying electricity such as in domestic purposes, grid integration, power generation and hybrid vehicle. Grid integration is one of the aspect is a necessary concern. This paper elaborates the control strategy installation necessary for grid integration. Most of the time, conventional inverters are used but in this paper the new multilevel inverter control strategy is taken for various purposes including cost, simple construction and less losses. This paper introduces a three level NPC inverter which uses space vector modulation for pulse generation. Three level NPC inverter contributes many benefits such as power quality improvement, reduction in harmonics, lower cost and improved efficiency. This document involves a novel control strategy with voltage oriented control using PR controller which helps the system to cope up the difficulties of the grid transmitting energy.

Validation of a Nonlinear Average Model of NPC Inverters Based on Experimental Investigations

Abstract This paper proposes a nonlinear average model of three levels NPC inverter. This model takes into account the semiconductor non-linearity and static characteristics of these devices. The proposed technique uses experimental results to evaluate the different devices parameters. The developed nonlinear average model allows dissipated power and junction temperature evaluation. Unlike the circuit model (fine model), the proposed method has less computational burden. It can be applied to three levels Neutral-Point-Clamped inverter (NPC).

도시철도 역사 신재생에너지 활용을 위한 멀티레벨 인버터 개발

Energy Saving Methods in existing railway vehicle are considered by active approach such as regenerative energy storage and utilization, eco driving, etc. On the other hands, energy saving measures in railway station are operated by passive method such as reduction of operating time in ventilation system, cooing system and power equipment. To reduce energy and for independence in railway system, it requires an active energy saving measures. It needs to its own power source besides the power source of electric supply company such as renewable energy and regenerative energy and take the advantage of power storage system and stored power are used in optimum time. This paper deal with 3-level NPC inverter and T-type NPC inverter that used in various multi-level topology applicable to the railway system.

Using Non Linear Average Model of NPC Inverter in DTC Control of Synchronous Machines

The Direct Torque Control (DTC) is known as an effective control method for high performance drives in a wide variety of industrial applications. This paper presents the Direct Torque Control (DTC) of an asynchronous machine fed by three levels NPC inverter. This inverter provides nearly sinusoidal voltages with very low distortion, using less switching devices. Due to the small dv/dt’s, torque ripple is greatly reduced. A nonlinear averaged modeling of the inverter was used to develop the control law. This kind of modeling allows a good tradeoff between simulation cost and precision. A simulation results are given to confirm the interest of the averaged modelling.

Improved design of three-level NPC inverters in comparison to two-level inverters

As voltage source 3-level NPC inverters are suitable for AC drives in average voltage and FACT applications in distribution systems, this report introduces optimized design of 3-level NPC inverter ...

Analysis of common mode voltage-"neutral shift" in medium voltage PWM adjustable speed drive (MV-ASD) systems

In this paper, an analysis of common mode voltage or "neutral lift" in the new emerging voltage source inverter type medium voltage adjustable speed drive (MV-ASD) systems is presented. Both cascaded multilevel (CML) inverter and 3-level NPC inverter topologies are analyzed. An equivalent circuit model to determine the common mode voltage stress is presented. Analysis and simulation results are discussed and worst case common mode voltage excursion is computed for an example 800 hp, 4160 V MV-ASD. It is shown that certain system components are excessively stressed and in the MV-ASD system these data are particularly useful in specifying system components and for proper design of the system. Possible effects of common mode voltage and its dv/dt on medium voltage motor bearings are discussed. A new multilevel PWM strategy is introduced which results in zero common-mode voltage. Simulation results are shown to illustrate the effectiveness of these schemes. Finally, experimental results from a 800 hp, 4160 V, MV-ASD system are presented.