scholarly journals Adaptive Damping Design of PMSG Integrated Power System with Virtual Synchronous Generator Control

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2037
Author(s):  
Jun Deng ◽  
Jianbo Wang ◽  
Shupeng Li ◽  
Haijing Zhang ◽  
Shutao Peng ◽  
...  

With the continuous development of wind power capacity, a large number of wind turbines connected by power electronic devices make the system inertia lower, which leads to the problem of system frequency stability degradation. The virtual synchronous generator (VSG) control can make wind turbines possess inertia and damping. However, the stochastic dynamic behavior of wind generation results in the stochastic changing of operating condition; this paper presents an adaptive subsynchronous oscillation (SSO) damping control method for the wind generation with VSG control. Firstly, the small signal model of the permanent magnet synchronous generator (PMSG) with VSG is built, and the model of state space is derived and built. The active power of PMSG is selected as the variable parameter vector to establish a polytopic linear variable parameter system model. Then, based on the hybrid H2/H∞ control method, each vertex state feedback matrix is solved by linear matrix inequality, and a subsynchronous oscillation adaptive damping controller with polytope is obtained. Finally, the 4-machine 2-area system connected to two PMSGs with VSG control is used as the test system for time domain simulation. The simulation results demonstrate that the LPV based adaptive damping controller could provide enough damping under the circumstances of wider changes of wind power outputs.

2020 ◽  
Vol 10 (20) ◽  
pp. 7282
Author(s):  
Zicong Zhang ◽  
Junghun Lee ◽  
Gilsoo Jang

With the continuous development of power electronics technology, variable-speed offshore wind turbines that penetrated the grid system caused the problem of inertia reduction. This study investigates the frequency stability of synchronous, offshore wind-farm integration through a modular-multilevel-converter high-voltage direct-current (MMC–HVDC) transmission system. When full-scale converter wind turbines (type 4) penetrate the AC grid, the AC system debilitates, and it becomes difficult to maintain the AC system frequency stability. In this paper, we present an improved inertial-response-control method to solve this problem. The mathematical model of the synchronous generator is based on the swing equation and is theoretically derived by establishing a MMC–HVDC. Based on the above model, the inertia constant is analyzed using a model that integrates the MMC–HVDC and offshore synchronous generator. With the new improved control method, a more sensitive and accurate inertia index can be obtained using the formula related to the effective short-circuit ratio of the AC system. Moreover, it is advantageous to provide a more accurate inertial control evaluation for AC systems under various conditions. Furthermore, the impact of the MMC–HVDC on system safety is assessed based on the capacitor time constant. This simulation was implemented using the PSCAD/EMTDC platform.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 398 ◽  
Author(s):  
Jun Deng ◽  
Nan Xia ◽  
Jungang Yin ◽  
Jiliang Jin ◽  
Shutao Peng ◽  
...  

With the continuous proliferation of renewable energy generation, distributed photovoltaic inverters operating at a maximum power point reduce the inertia of power systems, degrading system frequency stability and potentially causing severe oscillations in systems after being disturbed. The virtual synchronous generator (VSG) control method, which causes photovoltaic inverters to possess inertia and damping, now plays an important role in the field of distributed generation. However, while introducing the advantages of synchronous machines, problems with oscillations are also introduced and the stochastic fluctuation characteristic of photovoltaics results in the stochastic drifting of the operating point. This paper presents an adaptive controller parameter design method for a photovoltaic-VSG (PV-VSG) integrated power system. Firstly, a small-signal model of the PV-VSG is built and a state space model is deduced. Then, the small-signal stability and low frequency oscillation characteristics of the photovoltaic power generation system are analyzed. Finally, considering the limitations of system oscillations and the stochastic drifting of the operating point, a global optimization design method for controller parameters used to improve system stability is proposed. The time domain simulation shows that an optimized PV-VSG could provide sufficient damping in the case of photovoltaic power output changes across a wider range.


2014 ◽  
Vol 950 ◽  
pp. 314-320 ◽  
Author(s):  
Jun Jia ◽  
Xin Xin Hu ◽  
Ping Ping Han ◽  
Yan Ping Hu

With the scale of wind farm continuously increasing, when grid fault, the influences of the wind turbines connected to the grid on the stability of the power grid can never be ignored. Therefore, there are higher standards of the wind turbines’ abilities of fault ride-through (FRT) and producing reactive power. This paper studies the direct-drive wind power system, and the main point is the fault ride-through (FRT) of the permanent magnetic synchronous generator (PMSG) with Chopper. By establishing the dynamic model of PMSG under the environment of DigSILENT, this paper simulates the fault ride-through (FRT) of the direct-drive wind power system connecting into power grid. During the research, we focus on the stability of voltage about the Chopper to the DC bus under faults. What’s more, in this paper, we analysis the data about how the Chopper help the DC bus to improve its stability. The simulation results show that: when there is a fault on the point of common coupling, the permanent magnetic synchronous generator has the capability of fault ride-through (FRT). Especially when there is a voltage dip on the grid side, the permanent magnetic synchronous generator could produce reactive power for power grid, effectively preventing the system voltage from declining seriously, so as to improve the system stability under faults.


2021 ◽  
Vol 2087 (1) ◽  
pp. 012059
Author(s):  
Dongmei Xie ◽  
Changjian Li ◽  
Yanxi Jiang

Abstract Commissioned for wind power system there are two main types of generators, one is doubly fed induction generator(DFIG), the other is permanent magnetic synchronous generator(PMSG). Compared to DFIG unit, PMSG wind power system is more economical for manufacturing and maintenance. With the higher penetration rate of wind power generation in the grid, the need for the renewable power units to provide active frequency support yields relevant control characteristics in their power converters, for which the visual synchronous generator control exhibits promising features. This paper proposes a visual synchronous technology based PMSG wind power system. The simulation results verified the effectiveness of this proposed controller.


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