Three-level Converter Research Articles

Thermal Balance Modulation of Switching Devices for Hybrid-Clamped Three-Level Full-Bridge LLC Resonant Converter

Thermal Balance Modulation of Switching Devices for Hybrid-Clamped Three-Level Full-Bridge LLC Resonant Converter

Optimal Pulse Width Modulation of Three-Level Converters With Reduced Common-Mode Voltage

Optimal Pulse Width Modulation of Three-Level Converters With Reduced Common-Mode Voltage

Noninvasive Online Capacitor Monitoring Method for Three-Level Converter Based on Active Neutral-Point Current Adjustment

Capacitor monitoring is one of the effective measures to assess the health status of power converters. Although some conventional methods have been proposed, they require adding auxiliary current sensors, changing operation conditions, or deteriorating the output performance. The lack of noninvasive online capacitor monitoring methods is a great problem in an AC/DC/AC system. To address this urgent need, this article proposes a truly noninvasive online capacitor monitoring method specifically for three-level neutral-point-clamped converters. The word “noninvasive” means no additional sensors, no changes to operation conditions, and little influence on the output performance. It monitors capacitors by actively adjusting the neutral-point (NP) current to induce a ripple in the NP voltage. Then, it reconstructs the injected NP current based on the switching states and three-phase currents, and obtains the response ripple in the NP voltage through a recursive least square (RLS) filter. Finally, according to the relationship between the injected NP current and the response ripple in the NP voltage, it estimates the capacitance simply via a RLS observer. Both numerical simulation and experimental results are provided as well to verify the correctness and feasibility of the proposed method.

A virtual space vector modulation strategy for suppressing common-mode voltage in dual-output T-type three-level converters

A virtual space vector modulation strategy for suppressing common-mode voltage in dual-output T-type three-level converters

Sliding Mode Control of an Electric Vehicle Driven by a New Powertrain Technology Based on a Dual-Star Induction Machine

This article examines a new powertrain system for electric vehicles based on the dual-star induction machine, presented as a promising option due to its significant advantages in terms of performance, energy efficiency, and reliability. This system could play a key role in the evolution of electro-mobility technology. The dual-star induction machine reduces electromagnetic torque fluctuations, limits current harmonics, improves power factor, and enables half-speed operation. Our study focuses on the control strategy and operation of the traction chain for electric vehicles propelled by the dual-star induction machine (DSIM) using Matlab software with version 2017. We integrate the battery as the main energy source, along with three-level static converters for energy conversion in the vehicle’s four operating quadrants. We have opted for sliding mode control, which has proven to be feasible and robust against external disturbances. Although we have modeled driver behavior, we consider it as an aspect of control, to which we add the driving profile to guide our evaluation of the control to be used for vehicle operation. The results of our study demonstrate the reliability and robustness of DSIM for electric vehicle motorization and speed control. Promoting this technology is essential to improve the overall performance and efficiency of electric vehicles, especially in traction and braking modes for energy recovery. This underscores the importance of DSIM in the sustainable development of the electric transportation system.

PSO-enhanced discrete-time integrated sliding mode-based control of three-level NPC converter for grid-connected PV-FC distributed generation system

This study proposes the control of a three-level NPC converter applied in a PV-FC hybrid generation system based on discrete-time integral sliding mode control (DISMC) combined with the particle swarm optimization (PSO) technique. First, the comprehensive depiction and modeling of the system's main components are initially presented. Then, the controller's detailed design procedure is given. The sliding manifold is designed to have a fast dynamic response, and its stability analysis is verified using the Lyapunov direct method. Next, the optimization procedure is introduced to calculate the optimal values of the DISMC gains. Furthermore, a power management strategy is examined within the proposed control system to maximize the utility of the power produced by the hybrid system; the control is done through the designed PSO-DISMC to allow decoupled control of the active and reactive powers in two distinct modes of operation (the feeder-flow control (FFC) and the unit-power control (UPC) modes). The simulation of the approach is conducted in MATLAB/Simulink, and the findings demonstrate the effectiveness and robustness of the proposed control strategy.

Model predictive control for Vienna rectifier with constant frequency based on inductance parameters online identification

When the finite control set model predictive control (FCS-MPC) is applied to the three-level converter, there are problems such as large current harmonics, high requirements for the computing efficiency of the microcontroller, complex multi-objective optimization and limited output vector switching. In addition,the mismatch of inductance parameter may directly affect the observation accuracy of FCS-MPC. To solve the above problem,a double vector model predictive control strategy with constant frequency strategy based on the inductance parameters on-line identification is presented.First, a single objective cost function based on the direct power is constructed by optimizing the redundant vector which is selected to balance the neutral-point potential, the design of weighting factor is avoided.At the same time, in order to effectively reduce the grid current ripple under single vector modulation, space vector pulse width modulation (SVPWM) is realized by combining with zero vector control mode. And, a parameter identification method based on model reference adaptive system(MARS) is proposed to overcome the effect of model parameter mismatch.Finally, the results show that the proposed F-MPCCF has good steady-state and dynamic performance from the static, transient and neutral-point potential control.

Optimized low switching frequency modulation with neutral point voltage control for three-level converters

Optimized low switching frequency modulation with neutral point voltage control for three-level converters

Soft switching high step-up three-level boost DC-DC converter with Quasi Z-source for Photovoltaic application

A three-level Boost DC-DC converter is proposed in this paper. Quasi Z-source converter acts as an auxiliary circuit to create soft switching condition for all active elements. Consequently. The converter efficiency is very high. Using a three-level structure in the proposed converter causes the maximum voltage stress across the semiconductor devices is limited to half of the output voltage. The converter has a high voltage gain and a small number of elements. The converter is analyzed with details in all operating modes. Furthermore, the experimental results are obtained to prove the converter performance based on the theoretical considerations.

Switching Optimized Modulation for Direct Three-Level Matrix Converter

Switching Optimized Modulation for Direct Three-Level Matrix Converter

Constant On/Off-Time Digital Current Control and Design Methods in Three-Level Flying-Capacitor Boost Converters for Fast Transient and Voltage Balancing

Constant On/Off-Time Digital Current Control and Design Methods in Three-Level Flying-Capacitor Boost Converters for Fast Transient and Voltage Balancing

An Optimal Switching Sequence Model Predictive Control Scheme for the 3L-NPC Converter with Output LC Filter

In some applications of microgrids and distributed generation, it is necessary to feed islanded or stand-alone loads with high-quality voltage to provide low total harmonic distortion (THD). To fulfil these demands, an LC filter is usuallyconnected to the output terminals of power electronics converters. A cascaded voltage and current control loop with pulse-width modulation schemes are used to regulate the voltages and currents in these systems. However, these strategies have some drawbacks, particularly when multiple-input–multiple-output plants (MIMO) are controlled using single-input–single-output (SISO) design methods. This methodology usually produces a sluggish transient response and cross–coupling between different control loops and state variables. In this paper, a model predictive control (MPC) strategy based on the concept of optimal switching sequences (OSS) is designed to control voltage and current in an LC filter connected to a three-level neutral-point clamped converter. The strategy solves an optimisation problem to achieve control of the LC filter variables, i.e., currents and output voltages. Hardware-in-the-loop (HIL) results are obtained to validate the feasibility of the proposed strategy, using a PLECS–RT HIL platform and a dSPACE Microlab Box controller. In addition to the good dynamic performance of the proposed OSS–MPC, it is demonstrated using HIL results that the control algorithm is capable of obtaining low total harmonic distortion (THD) in the output voltage for different operating conditions.

A Reduced Common-Mode Voltage Control Scheme for Three-Level H10 Converter Considering Dead-Time Effect

A Reduced Common-Mode Voltage Control Scheme for Three-Level H10 Converter Considering Dead-Time Effect

A Honeycomb-Like Predictive Controller With a Reduced Computational Burden for Three-Level NPC Converters

A Honeycomb-Like Predictive Controller With a Reduced Computational Burden for Three-Level NPC Converters

Experimental Comparison of Carrier and Space Vector PWM Control Methods for Three-Phase NPC Converters

Multilevel converters are powerful converters in the medium-voltage high-power range. Inside this family of converters, the three-level neutral point clamped converter has its own importance. The main control methods associated with this converter are the carrier-based PWM with added DC components and the space vector PWM. Two of the most important features of the NPC converter are the neutral point balance and the output voltage spectrum. Both control methods efficiently manage the two characteristics. This paper experimentally compares these two issues and shows that the two methods produce almost the same results; the choice between one and the other should be made according to other requirements.

Model predictive control of NPC three-level grid-tied converter based on reconstructed current

Model predictive control of NPC three-level grid-tied converter based on reconstructed current

Design and control of utility grid-tied bipolar DC microgrid

Abstract This paper explains in detail the design and control of a utility grid-connected bipolar DC microgrid, which consists of a solar photovoltaic system (SPV), a wind energy conversion system (WECS), a battery energy storage system (BESS) at the DC bus, and a three-level neutral point clamped (NPC) converter to connect the DC microgrid to the utility grid. A three-level bidirectional DC–DC converter at the battery energy storage system (BESS) is controlled with model predictive current control (MPCC), and a three-level NPC converter is controlled with a voltage-oriented control based proportional resonant (VOC-PR) controller. The proposed MPCC scheme for the three-level bidirectional DC–DC converter and the VOC-PR control scheme for the three-level NPC converter coordinate with each other to balance and regulate the voltage at the bipolar DC microgrid, control the power flow to the loads at the DC microgrid and the load at the point of common connection (PCC), and also inject or draw power from the utility grid and BESS based on the availability of Renewable Energy Sources (RES). Simulation and experimental results are presented to demonstrate the effectiveness of the proposed MPCC control scheme.

A Hybrid Asymmetric Average Zero CMV PWM Strategy With Four Nearest Vectors to Optimize Harmonic Distortion for a Three-Level NPC Converter

A Hybrid Asymmetric Average Zero CMV PWM Strategy With Four Nearest Vectors to Optimize Harmonic Distortion for a Three-Level NPC Converter

Development of a Generalized Multilevel SVM and Capacitor Voltage Balancing Strategy for Multiphase Three-Level NPC Converters

Development of a Generalized Multilevel SVM and Capacitor Voltage Balancing Strategy for Multiphase Three-Level NPC Converters

Reconfiguration on Novel Unbalance Levels Strategy adopted in a Three-Level Bidirectional LLC Resonant Converter in HESS to EV Endurance Scheme

Reconfiguration on Novel Unbalance Levels Strategy adopted in a Three-Level Bidirectional LLC Resonant Converter in HESS to EV Endurance Scheme