A Delay Compensation Method to Improve the Current Control Performance of the LCL-Type Grid-Connected Inverter

2019 ◽  
Author(s):  
Lin Wang ◽  
Pengju Sun ◽  
Jie Wang ◽  
Kunlong Zhu ◽  
Tongyu Xue ◽  
...  
Keyword(s):  
Current Control ◽  
Compensation Method ◽  
Control Performance ◽  
Delay Compensation ◽  
Grid Connected Inverter

scholarly journals A General Double Vector-Based Model Predictive Current Control for the Dual Three-Phase Motors

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2000
Author(s):  
Qingqing Yuan ◽  
Ting Ma ◽  
Renji Zhao ◽  
Yumei Yang
Keyword(s):  
Duty Cycle ◽  
Control Period ◽  
Current Control ◽  
Control Performance ◽  
Delay Compensation ◽  
Voltage Vector ◽  
Three Phase ◽  
Speed Range ◽  
Full Speed ◽  
The Cost

Traditional model predictive current control (MPCC) for motors can only choose one optimal voltage vector during one control period, which creates problems of over-regulation or under-regulation for the current tracking. With zero vectors being injected in the chosen optimal voltage vector, the traditional MPCC can obtain better performance, which is called duty cycle MPCC. However, whether the traditional or the duty cycle MPCC is being applied to multiphase motors, it is more difficult for the phase to increase. In this paper, a general double vector-based MPCC mechanism has been studied for a dual three-phase permanent synchronous motor (PMSM) with dual Y shift 30° windings used in aerospace propulsion. Firstly, the choosing range of the second voltage vector in duty cycle MPCC was extended to an arbitrary vector; then, the cost function was rationally designed, and the delay compensation was added to improve the control performance as well. Compared with the traditional or duty cycle MPCC, this general double vector-based MPCC has better torque performance and fewer total harmonic distortions in the full speed range and under different load conditions.

scholarly journals An Improved Active Damping Method Based on Single-Loop Inverter Current Control for LCL Resonance in Grid-Connected Inverters

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiaofeng Wan ◽  
Xiaohua Ding ◽  
Hailin Hu
Keyword(s):  
Resonance Frequency ◽  
Sampling Method ◽  
Current Control ◽  
Active Damping ◽  
Compensation Method ◽  
System Stability ◽  
Delay Compensation ◽  
Lcl Filter ◽  
Single Loop ◽  
Control Delay

This paper investigates active damping of LCL filter resonance in grid-connected inverters with only inverter current feedback control, since it only needs to sample one current to realize both current control and inverter protection. The traditional single-loop inverter current control (SLICC) can damp the LCL filter resonance actively. However, if the control delay is considered in digital control, the system stability will depend on the ratio of the LCL resonance frequency f res to the sampling frequency f s , and the valid damping region is only up to f s / 6 . Considering that the design region of the LCL resonance frequency f res is up to f s / 2 , the system can easily become unstable due to the LCL resonance frequency shifting. Thus, this paper proposes an improved active damping method based on SLICC, including the asymmetric regular sampling method and delay compensation method. The improved sampling method minimizes the control delay without introducing a switching ripple, and the delay compensation method further compensates for the delay effect. With a proper parameter design, the upper limit of the valid damping region is extended up to f s / 2 , which can cover all the possible resonance frequencies, and it has inherent robustness against grid-impedance variation. Finally, a few simulations in MATLAB/SIMULINK and experiments based on a 6 kW prototype are performed to verify the theoretical analysis.

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