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Novel Single-State PWM Technique for Common-Mode Voltage Elimination in Multilevel Inverters
Nho-Van Nguyen,Hai-Thanh Quach,Hong-Hee Lee 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4
In this paper, a novel offset-based single-state pulse width modulation (PWM) method for achieving zero common-mode voltage (CMV) and reducing switching losses in multilevel inverters is presented. The specific active switching state of the zero common-mode (ZCM) voltage that approximates the reference voltage can be deduced from the switching state sequence of the reduced CMV phase disposition PWM (CMV PD PWM) method. From the reference leg voltages for the zero common-mode voltage, an N-to-2-level transformation defines a virtual two-level inverter and the corresponding nominal leg voltage references. The commutation process of the reduced CMV PD PWM method in a multilevel inverter and its outputs can be simply followed in a nominal switching time diagram for the virtual inverter. The characteristics of the reduced CMV PD PWM and the single-state PWM for zero common-mode voltage are analyzed in detail in this paper. The theoretical analysis of the proposed PWM method is verified by experimental results.
Carrier Based Single-State PWM Technique for Minimizing Vector Errors in Multilevel Inverters
Nguyen Van Nho,Quach Thanh Hai,Hong-Hee Lee 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.4
In this paper, a novel analysis of a carrier based PWM method for multilevel inverters is presented. The space vector PWM and carrier based PWM correlations in multilevel inverters are investigated in a nominal two-level switching diagram. The obtained results can be applied to design various carrier PWM techniques. In this paper, a carrier based single-state PWM technique, which reduces the switching number and optimizes the active voltage errors, is presented. This PWM technique can be advantageous if there are a large number of levels. The proposed method is mathematically formulated and demonstrated by simulations and experimental results.
NGUYEN, It Van,QUACH, Trinh To,NGUYEN, Tinh Thi Korea Distribution Science Association 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.10
On the underpinning theory of the Resource Based Theory, this research examines the impact of corporate social responsibility and green marketing strategy on business performance with the moderating role balanced scorecard. Corporate social responsibility concentrates on related to government, the environment, customers, and employees. Green marketing strategy concentrates on approaches in terms of green products, green prices, green places, and green promotion. Business performance is measured by groups of indicators financial, and non-financial. The moderating role balanced the scorecard at the financial, customer, process, learning, and growth level. Research results with survey data from 419 managers at different food enterprises in Ho Chi Minh City processed through the structural analysis method, showed that corporate social responsibility has the strongest positive impact on business performance, followed by the green marketing strategy as the second strong positive impact on the business performance and results also showed that the balanced scorecard moderating role increases the level of the strong positive impact of the above relationship. Besides, it also showed the difference in the demographic control variables. Based on the findings, some implications are drawn to help the managers of enterprises improve the moderating role balanced scorecard when implementing corporate social responsibility and green marketing strategies thereby contributing to increasing business performance.
Parametric study of a high-performance ammonia-fed SOFC standalone system
Thai-Quyen Quach,Van-Tien Giap,Dong Keun Lee,Israel Torres Pineda,Kook Young Ahn 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6
Ammonia-fed solid oxide fuel cell (SOFC) power generation systems are very promising owing to their high efficiency and ease of fuel storage. However, understanding the complexity of fuel cell stacks and systems supplied by ammonia remains challenging. Therefore, it is proposed to investigate the standalone SOFC system to clearly elucidate the behavior of the stack and realize facile implementation. In this study, the stack was modeled and validated using experimental data to confirm its output characteristics. The system efficiency was then calculated under various operating conditions, such as current density, fuel utilization, and stack in/out temperature. The results show that the system efficiency is approximately 54 % and is highly dependent on fuel utilization and current density but not on temperature differences. However, the system can only operate at a temperature difference of 65 °C or higher owing to the effectiveness of the heat exchanger on the fuel side.
Carrier Based Single-State PWM Technique for Minimizing Vector Errors in Multilevel Inverters
Nho, Nguyen Van,Hai, Quach Thanh,Lee, Hong-Hee The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.4
In this paper, a novel analysis of a carrier based PWM method for multilevel inverters is presented. The space vector PWM and carrier based PWM correlations in multilevel inverters are investigated in a nominal two-level switching diagram. The obtained results can be applied to design various carrier PWM techniques. In this paper, a carrier based single-state PWM technique, which reduces the switching number and optimizes the active voltage errors, is presented. This PWM technique can be advantageous if there are a large number of levels. The proposed method is mathematically formulated and demonstrated by simulations and experimental results.
Novel Single-State PWM Technique for Common-Mode Voltage Elimination in Multilevel Inverters
Nguyen, Nho-Van,Quach, Hai-Thanh,Lee, Hong-Hee The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4
In this paper, a novel offset-based single-state pulse width modulation (PWM) method for achieving zero common-mode voltage (CMV) and reducing switching losses in multilevel inverters is presented. The specific active switching state of the zero common-mode (ZCM) voltage that approximates the reference voltage can be deduced from the switching state sequence of the reduced CMV phase disposition PWM (CMV PD PWM) method. From the reference leg voltages for the zero common-mode voltage, an N-to-2-level transformation defines a virtual two-level inverter and the corresponding nominal leg voltage references. The commutation process of the reduced CMV PD PWM method in a multilevel inverter and its outputs can be simply followed in a nominal switching time diagram for the virtual inverter. The characteristics of the reduced CMV PD PWM and the single-state PWM for zero common-mode voltage are analyzed in detail in this paper. The theoretical analysis of the proposed PWM method is verified by experimental results.
Kha Quang Quach,김형수,Tuyen Van Nguyen,Chunlei Xia,조운석,전태수 한국통합생물학회 2015 Animal cells and systems Vol.19 No.4
Variance and invariance residing in multi-individual movement of zebrafish under chemical stress were addressed concurrently before and after treatment with formaldehyde. Variance was observed in movement parameters. Without treatment, linear speed was highest in groups with two-individuals, followed by those with one- and four-individuals. Following treatment, linear speed decreased significantly in groups with one- and two-individuals, but not in those with four-individuals. Inter-distances between two-individuals in groups with two-individuals decreased markedly after treatment, whereas inter-distances between two randomly selected individuals in the groups with four-individuals were not affected. The zero- and peak-values in the time-lag of autocorrelation of inter-distances decreased further after treatment in groups of two individuals relative to those in groups of four individuals. However, the empirical transition probability matrix between predefined behavioral patterns remained invariant among groups with different numbers of individuals as well as before and after treatment. Variance and invariance in multi-individual behaviors are suitable in expressing complex behaviors under chemical stress and could be a reference for detecting contaminants in the environment using indicator species.