scholarly journals An improved capacitor voltage full feedforward control strategy for LCL‐type grid‐connected inverter based on control delay compensation

2021 ◽  
Author(s):  
Xingwu Yang ◽  
Guokuai Wu ◽  
Zhicheng Meng ◽  
Yani Wang ◽  
Liang Ji ◽  
...  
Keyword(s):  
Control Strategy ◽  
Feedforward Control ◽  
Delay Compensation ◽  
Control Delay ◽  
Capacitor Voltage ◽  
Grid Connected Inverter

scholarly journals An improving control strategy for grid -connected current in weak grid

2021 ◽  
Vol 252 ◽  
pp. 01010
Author(s):  
Deng Songyuan ◽  
Zhao Xia
Keyword(s):  
Control Strategy ◽  
Feedforward Control ◽  
Power Grid ◽  
Impedance Analysis ◽  
System Stability ◽  
Grid Impedance ◽  
Grid Connected Inverter ◽  
The Stability ◽  
Proportional Controller ◽  
Low Order

The traditional proportional feedforward control strategy can suppress the low order harmonics in the strong power grid, but in the weak power grid environment, the grid impedance will have an adverse impact on the stability of the system, resulting in the proportional feedforward control can not suppress the low order harmonics well. In order to solve this problem, a control strategy combining resonant feedforward and new repetitive proportional controller is proposed. Firstly, the stability of traditional proportional feedforward and resonant feedforward systems is analyzed and compared by impedance analysis method. Then, a new repetitive controller is added to suppress low order harmonics based on resonant feedforward control, and the stability of single-phase LCL grid connected inverter system is analyzed Matlab / Simulink is used to simulate and verify the system. The results show that the system stability and the ability to suppress low order harmonics are significantly improved.

scholarly journals Control Strategy for a Grid-Connected Inverter under Unbalanced Network Conditions—A Disturbance Observer-Based Decoupled Current Approach

Energies ◽  
2017 ◽  
Vol 10 (7) ◽  
pp. 1067 ◽  
Author(s):  
Emre Ozsoy ◽  
Sanjeevikumar Padmanaban ◽  
Lucian Mihet-Popa ◽  
Viliam Fedák ◽  
Fiaz Ahmad ◽  
...  
Keyword(s):  
Control Strategy ◽  
Disturbance Observer ◽  
Current Approach ◽  
Grid Connected Inverter ◽  
Unbalanced Network

scholarly journals Coordinated Control of RSC and GSC for DFIG System under Harmonically Distorted Grid Considering Inter-Harmonics

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 28 ◽  
Author(s):  
Bo Pang ◽  
Hui Dai ◽  
Feng Li ◽  
Heng Nian
Keyword(s):  
Theoretical Analysis ◽  
Control Strategy ◽  
Coordinated Control ◽  
Delay Compensation ◽  
Pass Filter ◽  
Grid Connection ◽  
Distorted Grid ◽  
Negative Impacts ◽  
Doubly Fed ◽  
Grid Side

For improving the performance of a doubly fed induction generator (DFIG) system under a harmonically distorted grid, this paper proposes a coordinated control strategy which is effective for grid inter-harmonics as well as grid integer harmonics. In order to suppress the negative impacts caused by grid harmonics, including inter-harmonics, this paper introduces an additional harmonics suppression controller, which contains a Chebyshev high-pass filter and a modified lead element considering the delay compensation. The proposed controller is employed in the rotor side converter (RSC) and grid side converter (GSC). Based on the proposed harmonics suppression controller, a coordinated control strategy between RSC and GSC is developed, in which the control targets, including the sinusoidal output current, constant power, or steady generator torque, can be achieved for DFIG, while GSC is responsible for maintaining the sinusoidal total current to guarantee the power quality of the grid connection. The effectiveness of the proposed method is verified by the theoretical analysis, and the experimental results derived using a 1 kW DFIG system validate the correctness of the theoretical analysis.

Performance Improvement of SVPWM-Based Three-Phase Grid-Connected Inverters

2013 ◽  
Vol 732-733 ◽  
pp. 1261-1264
Author(s):  
Zhi Lei Yao ◽  
Lan Xiao ◽  
Jing Xu
Keyword(s):  
Dynamic Response ◽  
Control Strategy ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Grid Current ◽  
Current Controller ◽  
Three Phase ◽  
Reference Grid ◽  
Grid Connected Inverter

An improved control strategy for three-phase grid-connected inverters with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d-and q-axes grid currents is interacted in the traditional control method, and the waveform quality of the grid current is poor. As the reference output voltage cannot directly reflect the change of the reference grid current with the traditional control strategy, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d-and q-axes grid currents in the decoupled components of the grid current controller are substituted by the d-and q-axes reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results show that the grid-connected inverter with the improved control strategy has high waveform quality of the grid current and fast dynamic response.

scholarly journals Resonance overvoltage control algorithms in long cable frequency conversion drive based on discrete mathematics

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 408-418
Author(s):  
Yonghong Deng ◽  
Quanzhu Zhang
Keyword(s):  
Mathematical Model ◽  
Control Strategy ◽  
Frequency Conversion ◽  
Balance Control ◽  
Frequency Converter ◽  
Active Power ◽  
Drive System ◽  
Discrete Mathematics ◽  
Power Controller ◽  
Capacitor Voltage

AbstractIn order to solve the problem that the long cable variable voltage and variable frequency (VVVF) system does not adopt an effective capacitor voltage sharing control method, resulting in a poor effect of resonance overvoltage control, the resonance overvoltage control algorithm of the long cable VVVF system based on discrete mathematics is studied. First, the long cable frequency conversion drive system is established. In order to ensure voltage loss in the range of motor requirements, a frequency converter–cable–motor (ICM) system connection mode is used to maintain the system operation. Based on the research of the capacitor voltage balance control strategy of a long cable frequency conversion drive system, the discrete mathematical model of the AC side of the ICM system is established by using this control strategy. The improved constant active power controller is obtained by establishing the mathematical model, and the resonant overvoltage in a long cable frequency conversion drive is realized by using the constant active power controller. The experimental results show that the algorithm can effectively control the resonance overvoltage phenomenon in the long cable frequency control system, and the control accuracy is over 97%. It has good performance and can be applied in practice.

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