Operational strategy for multi‐converter based variable speed wind generator during network fault

Abstract

SUMMARYThis paper proposes novel multiconverter operation and control scheme for variable speed wind energy conversion system to withstand against grid fault. The full or partial rating frequency converters (FCs), in general, are widely used in variable speed wind turbine (VSWT) driven wind generators. Among the variable speed wind generators, permanent magnet synchronous generator (PMSG), which uses a full rating FC for grid interfacing, is drawing much attention nowadays due to its salient features. However, considering the factors such as higher-reliability, higher efficiency, and lower harmonics, the multiconverter based topology might be preferable instead of using a full rating FC. This paper proposes a coordinated control scheme for multiple parallel-connected FC units integrated with VSWT driving PMSG to augments the transient performance during a network disturbance. Multimode operation (inverter and rectifier) of the individual FC unit is another salient feature of this study.

Direct drive surge wave energy converter with grid integration functionality

“…By substituting (12) in (1), electrical generator is linked to DDSWEC; hence, it is possible to achieve the output voltage and current waveforms by exciting the WEC. The subsequent section would provide the frequency domain analysis for both mechanical (WEC) and electrical (PTO) parts of the DDSWEC validating its designated characteristics.…”

“…As proposing a new design of the WECs, namely, DDSWEC structure, including a more detailed power electronics control strategies for the input converter besides the hydrodynamic modeling of the structure causes the present study not to be a consistent whole. However, as it has been earlier mentioned in (12), the control of i q component in the linear machine depends to the hydrodynamic model and behavior of the ocean waves, which itself is a complicated control modeling and approach. Thus, this issue is considered as a future research topic to scrutinize the proposed structure for harvesting more power from the ocean waves.…”

“…The mathematical basis of the mechanical and electrical systems is also established which lets us to evaluate the performance of the DDSWEC encountering waves with different frequencies. The variable behavior of natural resources such as wind and ocean waves induces voltages with both variable frequency and magnitude, which are unfavorable for the grid integration . Accordingly, a full‐scale back‐to‐back converter with both generator and grid‐side controls is applied to produce constant voltage and frequency required for integrating DDSWEC to the main electric grid.…”

Current balancer-based grid-connected parallel inverters for high power wind-power system

“…Wind energy has nowadays become the fastest developing renewable energy [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Its individual wind generator's capacity increases rapidly with multi-mega-watt scale [14], which definitely anticipates the large capacity of grid-connected inverters.…”