skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Adapted near‐state PWM for dual two‐level inverters in order to reduce common‐mode voltage and switching losses
In this paper, a near‐state pulse‐width modulation (NSPWM) algorithm is proposed and implemented on dual‐two‐level voltage‐source inverters (D2L‐VSIs) in order to reduce the common‐mode voltage (CMV), the inverter switching losses, the current total harmonic distortion, and the side effects of bearing currents ‐‐compared with space vector modulation (SVM) and PWM7. To gain these goals, two conventional two‐level inverters of the D2L‐VSI are controlled, separately, with specific switching sequences and an adjusted phase difference between the carriers of two inverters. For evaluating and comparing these PWM techniques mathematically, both CMV root mean square generated and switching losses of the D2L‐VSI are formulated as a function of the power factor of the D2L‐VSI, which is driven by the methods detailed in this study. Eventually, theories and analysis, as well as simulations and experimental results ‐‐which are generated by MATLAB/Simulink environment and a 300 W scaled‐down D2LVSI prototype, respectively ‐‐authenticate the superiority of the proposed NSPWM over both SVM and PWM7.  more » « less
Award ID(s):
1808279
PAR ID:
10570793
Author(s) / Creator(s):
 ;  ;  ;  ;  
Publisher / Repository:
DOI PREFIX: 10.1049
Date Published:
Journal Name:
IET Power Electronics
Volume:
12
Issue:
4
ISSN:
1755-4535
Format(s):
Medium: X Size: p. 676-685
Size(s):
p. 676-685
Sponsoring Org:
National Science Foundation
More Like this
  1. ; (, Energies)
    null (Ed.)
    The interconnection of distributed energy resources (DERs) in microgrids (MGs) operating in both islanded and grid-connected modes require coordinated control strategies. DERs are interfaced with voltage source inverters (VSIs) enabling interconnection. This paper proposes a load demand sharing scheme for the parallel operation of VSIs in an islanded voltage source inverter-based microgrid (VSI-MG). The ride-through capability of a heavily loaded VSI-MG, where some of the VSIs are fully loaded due to the occurrence of an event is investigated. In developing analytical equations to model the VSI, the concept of virtual synchronous machines (VSM) is applied to enable the VSI mimic the inertia effect of synchronous machines. A power frame transformation (PFT) that takes the line ratios of the MG network into account is also incorporated to yield satisfactory transient responses of both network frequency and bus voltages in the MG network. A Jacobian-based method is then developed to take into account the operational capacity of each VSI in the VSI-MG. The resulting amendable droop control constrains the VSIs within their power capabilities when an event occurs. Simulation results presented within demonstrate the effectiveness of the proposed procedure which has great potential to facilitate efforts in maintaining system reliability and resiliency. 
    more » « less
  2. ; ; ; ; ; ; (, 2018 9th IEEE International Symposium on Power Electronics for Distributed Generation Systems (PEDG))
    The increasing importance of power electronic converters in supplying electrical energy to utility grids places a higher priority to detect and protect against fault conditions. Fault detection and isolation are particularly important for inverters that provide black-start recovery for microgrids since these converters provide the energy source for restoration after a power outage. This paper presents a new fault detection and location method for Cascaded H-Bridge (CHB) multilevel inverters. The new fault detection method is based on monitoring the output voltage of each cell and output current directions along with each switch’s state. By monitoring each cell’s output voltage and current direction, the faulty cell can be detected and isolated. After the faulty cell is detected, the faulty switch can be located by comparing the current direction with the switching states. This technique is implemented with Level-Shifted Pulse Width Modulation (LS-PWM) in order to maintain acceptable total harmonic distortion (THD) levels at the converter. The proposed method can be implemented for a CHB with any number of cells, can operate with nonlinear loads, and offers very fast detection times. Simulation and experimental results verify the performance of this method. 
    more » « less
  3. ; (, IEEE Transactions on Industry Applications)
    Battery energy storage systems are widely used for renewable power generation and electric transportation systems. Bidirectional DC-DC converters (BDCs) are key components in such systems, enabling bidirectional power flow in battery charging and discharging modes. BDCs can be categorized into isolated and non-isolated. Non-isolated BDCs have lower volume, weight, and power losses, suitable for compact structures without needing galvanic isolation. In this paper, a comprehensive literature review is conducted for non-isolated BDCs, covering soft switching, current ripple reduction, high voltage gain and resiliency techniques. Soft switching aims to reduce switching losses and improve efficiency, including auxiliary circuits and non-auxiliary methods, such as interleaved structures, phase-shift modulation, and synchronous rectification. Current ripple reduction focuses on capacitive loop configurations, interleaved structures, and coupled inductor-based methods. Batteries are low-voltage power sources, BDCs can increase the output voltage to a level required by the applications through an appropriate voltage gain, and high voltage gain techniques include capacitor-based, magnetic-based, and combined networks, and mixed structures. Resiliency is explored to ensure reliable operations under adverse conditions. This review provides valuable insights into developing more efficient, reliable, and high-performance BDCs, addressing the evolving demands of modern energy systems. Future research directions in non-isolated BDCs are recommended in this paper. 
    more » « less
  4. ; ; (, IET Smart Grid)
    Abstract This study relies on an experimental approach, utilising real data from multiple photovoltaic (PV) sites located in the US Northeaster region, to inspect how different inverter reactive and active power settings impact gird voltage regulation and inverter life expectancy. These voltage regulation schemes come at a cost for the operator. Data from different solar sites with inverters running at different reactive and active power settings were analysed to compare operational trade‐offs. These trade‐offs range from production losses to shortening the lifetime of the inverters. Voltage versus reactive power plots were analysed to show production losses, while the thermal analysis was used to correlate with the inverter life expectancy. 
    more » « less
  5. ; (, 2024 IEEE Energy Conversion Congress and Exposition (ECCE))
    It is widely recognized that the number of switching turn-on/off actions is proportional to the switching loss. However, Y-Matrix Modulated (YMM) based Modular Multi-level Converter (MMC) has a significantly larger number of switching actions in each fundamental cycle compared to phase shift and level shift modulation methods in order to achieve self-voltage balancing. Given the large amount of switching patterns provided by high level MMCs, the analytical methods make it hard to find the optimal switching scheme. In this paper, a general approach for finding the N-level switched capacitor MMC (SC-MMC) optimal switching scheme using Genetic Algorithm (GA) is proposed. The main objective is to propose a heuristic method to minimize the switching actions with self voltage balancing for SC-MMC. Case studies have been implemented on four-level, eleven-level, and fifty-level SC-MMCs. The optimal solution has also been evaluated in terms of the computational complexity, capacitor voltage ripple, and total harmonic distortion (THD) to validate the effectiveness of the proposed method. The simulation results demonstrate the computational efficiency of the proposed algorithm in comparison to the analytical method. Moreover, the proposed algorithm can achieve a substantial 22% reduction in switching actions compared to the original switching pattern. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email