scholarly journals A New Soft-Switching Solution in Three-Level Neutral-Point-Clamped Voltage Source Inverters

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2247
Author(s):  
Zbigniew Szular ◽  
Bartosz Rozegnal ◽  
Witold Mazgaj
Keyword(s):  
Control System ◽  
Control Algorithm ◽  
Control Method ◽  
Neutral Point ◽  
Soft Switching ◽  
Voltage Source ◽  
Voltage Source Inverters ◽  
Switching Losses ◽  
Switching Method ◽  
Selection Of

This paper presents a new soft-switching solution recommended for three-level neutral-point-clamped inverters. The operation principles of the proposed solution, working stages, selection of elements, and the control algorithm are comprehensively discussed herein. The control method of the inverter main switches is the same as that of the switches of an inverter operating according to the hard-switching technique. The correctness of the proposed solution was confirmed by the results of different tests using a laboratory neutral-point-clamped inverter with rated parameters of 3 kW, 2 × 150 V, 12 A, and 3 kHz. Numerical analyses were performed for the inverter of rated power 1.2 MW. The switching losses of the inverter operating with the proposed solution were compared with those of an inverter with hard-switching method. The proposed soft-switching solution increased the inverter efficiency and its competitiveness in relation to other proposals because there were no connections between switches and capacitors or inductors, which pose a risk of damaging the inverter when disturbances in the control system appear.

scholarly journals Model Predictive Current Control Method with Improved Performances for Three-Phase Voltage Source Inverters

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 625 ◽  
Author(s):  
Eun-Su Jun ◽  
So-young Park ◽  
Sangshin Kwak
Keyword(s):  
Control Method ◽  
Harmonic Distortion ◽  
Sampling Period ◽  
Current Control ◽  
Voltage Source ◽  
Phase Voltage ◽  
Small Current ◽  
Voltage Source Inverters ◽  
Switching Losses ◽  
Three Phase

In this paper, the model predictive current control (MPCC) method using two vectors has been proposed to control output currents of three-phase voltage source inverters (VSIs) with small current errors and current ripples. Also, the proposed method can reduce switching losses by applying the vector pre-selection technique to the MPCC for the VSI. The VSI generates seven voltage vectors to control the output currents, but the proposed method uses four available voltage vectors with one switch, which are classified by the vector pre-selection method clamping one leg and conducting the largest output current among the three legs to reduce the switching losses. In the proposed method, selecting two future voltage vectors among the four voltage vectors and dividing them in a future sampling period are determined by an optimization process. The proposed method results in the lower total loss, better total harmonic distortion (THD), and smaller current errors than the conventional method with half the sampling period of the proposed method due to the optimal process. Simulation and experimental results of the three-phase VSIs are presented in order to verify the effectiveness of the proposed method.

scholarly journals Adaptive Smart Control Method for Electric Vehicle Wireless Charging System

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2685 ◽  
Author(s):  
Lingbing Gong ◽  
Chunyan Xiao ◽  
Bin Cao ◽  
Yuliang Zhou
Keyword(s):  
Control System ◽  
Control Method ◽  
Characteristic Curve ◽  
Constant Current ◽  
Voltage Source ◽  
Wireless Charging ◽  
Charging Time ◽  
Multi Stage ◽  
Smart Charging ◽  
Smart Control

In order to shorten the wireless charging time of electric vehicles (EVs) and achieve stable charging, an adaptive smart control method for EV wireless charging is proposed in the paper. The method dynamically tracks the rechargeable battery state during the whole charging process, realizes multi-stage charging of constant current (CC) or constant voltage (CV) by switching two kinds of compensation networks of bilateral L3C and L3C-C, and regulates the charging voltage and current to make it as close as possible to the battery charging characteristic curve. This method can be implemented because the voltage source connected to the coupler and the compensation networks of bilateral L3C and L3C-C have the CC and CV source characteristics, respectively. On the basis of the established adaptive smart control system of EV wireless charging, the experiments of wireless data transmission and adaptive smart charging were conducted. The results showed that the designed control system had a response time of less than 200 ms and strong anti-interference ability and it shortened the charging time by about 16% compared with the time using traditional charging methods, thereby achieving a fast, stable, safe, and complete wireless charging process.

scholarly journals HIGH FREQUENCY BOOST CONVERTER EMPLOYING SOFT SWITCHING AUXILIARY RESONANT CIRCUIT

2013 ◽  
pp. 262-267
Author(s):  
G. NARESH GOUD ◽  
Y. LAKSHMI DEEPA ◽  
G.DILLI BABU ◽  
P. RAJASEKHAR ◽  
N. GANGADHER
Keyword(s):  
Theoretical Analysis ◽  
High Frequency ◽  
Boost Converter ◽  
Soft Switching ◽  
Resonant Circuit ◽  
Switching Converter ◽  
Turn On ◽  
Switching Losses ◽  
Resonant Inductor ◽  
Switching Method

A new soft-switching boost converter is proposed in this paper. The conventional boost converter generates switching losses at turn ON and OFF, and this causes a reduction in the whole system’s efficiency. The proposed boost converter utilizes a soft switching method using an auxiliary circuit with a resonant inductor and capacitor, auxiliary switch, and diodes. Therefore, the proposed soft-switching boost converter reduces switching losses more than the conventional hard-switching converter. The efficiency, which is about 91% in hard switching, increases to about 97% in the proposed soft-switching converter. In this paper, the performance of the proposed soft-switching boost converter is verified through the theoretical analysis, simulation, and experimental results.

scholarly journals New adaptive droop control with combined line impedance estimation method for parallel inverters

2016 ◽  
Vol 19 (4) ◽  
pp. 45-64
Author(s):  
Phuong Minh Le ◽  
Duy Vo Duc Hoang ◽  
Hoa Thi Xuan Pham ◽  
Huy Minh Nguyen
Keyword(s):  
Kalman Filter ◽  
Control Method ◽  
Least Squares Method ◽  
Estimation Method ◽  
Load Sharing ◽  
Phase Lock Loop ◽  
Power Sharing ◽  
Voltage Source ◽  
Droop Control ◽  
Voltage Source Inverters

This paper presents a new load sharing control between paralleled three-phase inverters in an islanded-microgrid based on the line impedance estimation online by the use of the Kalman filter. We can solve the mismatch of power sharing when the line impedance changes due to the temperature and frequency, significant differences of line parameters and requirements of Plug-and-Play mode of inverters connected to the microgrid. Moreover, the paper also presents a new Droop control method working with the line impedance which is different from the Droop traditional algorithm when the line impedance is assumed pure resistance R or pure inductance X. In the paper, the line impedance estimation for parallel inverters uses the least squares method combined with Kalman filter. In addition, secondary control loops are designed to restore the voltage amplitude and frequency of the microgrid by using a combined nominal value SOGI-PLL with generalized integral block and phase lock loop to exactly monitor the voltage magnitude and frequency phase at common PCC. Control model has been simulated in Matlab/Simulink with three voltage source inverters connected in parallel for different ratios of the power sharing. The simulation results have shown the accuracy of the proposed control method. Therefore, the proposed adaptive droop control method based on line impedance estimation can be an alternative one for load sharing control in islanded microgrids.

A vector control system using a neutral-point-clamped voltage-source pwm inverter

1993 ◽  
Vol 113 (5) ◽  
pp. 93-101
Author(s):  
Satoshi Ogasawara ◽  
Tadashi Sawada ◽  
Keiichi Abe ◽  
Hirofumi Akagi
Keyword(s):  
Control System ◽  
Vector Control ◽  
Neutral Point ◽  
Voltage Source ◽  
Pwm Inverter ◽  
Vector Control System
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