Grid-voltage feedforward based control for grid-connected LCL-filtered inverter with high robustness and low grid current distortion in weak grid

Xu, Jinming; Qian, Qiang; Xie, Shaojun; Zhang, Binfeng

doi:10.1109/apec.2016.7468131

Cited by 35 publications

(12 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to (3), f res varies from −16.7% to + 25% for ± 20% fluctuations of LCL ‐filter. Moreover, when L g varies widely, f res reduces much smaller [25]. But, note that the decrease of f res does not break the criterion in (12).…”

Section: Proposed Design Criteria For Single‐loop Controlled Lcl‐fimentioning

confidence: 99%

Design of LCL ‐filter considering the control impact for grid‐connected inverter with one current feedback only

Xie

Huang

et al. 2017

IET Power Electronics

Self Cite

View full text Add to dashboard Cite

An LCL-filter draws much attention in grid-connected applications, but the design faces challenges. The LCL and controller parameters are interdependent and inter-restricted as the grid current quality and control stability rely on the parameters of them both. In the past, researchers found that extra sensors or complex algorithms were required for the stability when the LCL parameters were designed independently. Consequently, the system cost and complexity were increased. Indeed, the LCL-filter with the delay-dependent single-loop current control can be stable if the LCL parameters are properly selected. Based on this thought, this study proposes to design the LCL parameters by considering their impact on the stability and dynamic of the inverter. Extra sensors or complex algorithms are no longer required. Based on establishing the model of the single-loop inverter-side current controlled inverter, the criteria of LCL design are obtained in order to improve the stability and the rejections of low-order and switching current harmonics. Based on those design criteria, a step-by-step procedure is proposed. Selected results have been provided to demonstrate the effectiveness of the proposed design.

show abstract

Section: Proposed Design Criteria For Single‐loop Controlled Lcl‐fimentioning

confidence: 99%

Design of LCL ‐filter considering the control impact for grid‐connected inverter with one current feedback only

Xie

Huang

et al. 2017

IET Power Electronics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Proportional voltage feed-forward reduces total harmonics distortion, but also decreases the phase margin. Therefore, in most cases, a feedforward of fundamental voltage is used [12]. Although feedforward of fundamental voltage increases the phase margin, it is less helpful in the reduction of total harmonic distortion.…”

Section: Introductionmentioning

confidence: 99%

An Adaptive Hybrid Control of Grid Tied Inverter for the Reduction of Total Harmonic Distortion and Improvement of Robustness against Grid Impedance Variation

et al. 2022

View full text Add to dashboard Cite

Background: Grid-tied inverters play an efficient role in the integration of renewable energy resources with utility grids. Motivation: However, the interconnection between power converters and the grid has been seen to be responsible for various stability issues such as weak grid, and under weak grid conditions the injection of power to the grid becomes a challenging task due to continuously varying grid impedance affecting the stability margins as a result. Additionally, the grid impedance-related issues boost the voltage harmonics which further devalue its performance. These voltage harmonics propagate through the Phase-Locked Loop (PLL) circuit to the control unit of the inverter which in turn amplifies the low order harmonics of the inverter. Method: The aim of this research is to introduce a novel strategy that decreases the effect of grid impedance-variations on the performance and stability of an inverter. Hence, an adaptive hybrid mode control technique consisting of two parts is proposed in this research. The current regulator part is implemented in a synchronous reference frame for its gain and time parameters to improve the performance, stability, and response time. The adaptive harmonic compensators are implemented in a stationary reference frame for harmonic compensation purposes. This adaptive nature of harmonic compensator can effectively work in the case of frequency variation where the fixed value based harmonic compensator fails. Results: The adaptive harmonic compensators improve the performance by reducing total harmonic distortion (THD), reduce computation and improve stability when the grid has distorted voltage, variation in grid impedance and frequency. Impact and utility: Our results show that the system becomes less sensitive to grid impedance variations which makes the proposed technique very relevant to the stability performance applications.

show abstract

“…However, such methods are easy to destabilise the system under the weak grid due to the influence of non‐negligible grid impedance [23, 24]. For this reason, Xu et al [25] proposed a method to add a second‐order generalised integrator (SOGI) to the feedforward channel, this scheme can effectively improve the system's robustness to the grid impedance but has poor ability to suppress low‐order grid background harmonics and it is necessary to add additional multi‐resonance controllers. Cespedes and Sun [26] proposed an online measurement technology of grid impedance, which could be adopted to correct the problems caused by grid impedance on the system loop gain in real‐time.…”

Section: Introductionmentioning

confidence: 99%

Feedforward phase compensation method of LCL grid‐connected inverter based on all‐pass filter in weak grid

Xue

Sun

et al. 2020

IET power electron.

View full text Add to dashboard Cite

Inverter-side current feedback control (ICFC) has been extensively adopted in distributed generation systems because of its simple implementation and better consistency with actual operating conditions. At the same time, when there are a large number of background harmonics in the grid, capacitor voltage feedforward (CVF) is usually added to the system for its suppression. This method could make the system keep the first-order characteristics under the analogue control. However, under digital control, due to the digital control delay, a reverse resonance peak will be generated in the loop gain, which makes the system unstable in the weak grid. In order to solve the aforementioned problems, this study proposes a feedforward phase compensation method of LCL grid-connected inverter based on the all-pass filter (AF). By introducing AF into the CVF channel, the phase lag in the range of reverse resonance peak frequency is compensated, so as to enhance the robustness of the system in the weak grid. At the same time, this study gives the detailed design process of the proposed method. Experimental results on a 3-kW prototype are provided, and the effectiveness of the proposed control method is verified..

show abstract

Grid-voltage feedforward based control for grid-connected LCL-filtered inverter with high robustness and low grid current distortion in weak grid

Cited by 35 publications

References 24 publications

Design of LCL ‐filter considering the control impact for grid‐connected inverter with one current feedback only

Design of LCL ‐filter considering the control impact for grid‐connected inverter with one current feedback only

An Adaptive Hybrid Control of Grid Tied Inverter for the Reduction of Total Harmonic Distortion and Improvement of Robustness against Grid Impedance Variation

Feedforward phase compensation method of LCL grid‐connected inverter based on all‐pass filter in weak grid

Contact Info

Product

Resources

About