Stability improvement of current control by voltage feedforward considering a large synchronous inductance of diesel generator

Jo, Jongmin; Cha, Hanju

doi:10.1109/ecce.2017.8095974

Cited by 3 publications

(7 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar conclusion as (15) has been put forward by [23], [24]. References [23], [24] mainly focuses on the capability to suppress grid voltage harmonics of the ICF control, and proposes a complete CVF method, where the form of G vf (s) is expressed as (1+sG c (s)C f + s 2 L 1 C f ).…”

Section: Grid Voltage Harmonic Suppressionmentioning

confidence: 61%

“…So, all the parameters in (13) have been obtained (the parameters of the HPF are the same as Section III). In light of (13), there is an ideal situation: if G vf (s) satisfies the condition in (15), the harmonics of the grid voltage can be totally suppressed. But the condition in (15) includes a first-order derivative and a second-order derivative, which is impractical in digital control system.…”

Section: Grid Voltage Harmonic Suppressionmentioning

confidence: 99%

“…Recently, the effect of the capacitor voltage feedforward (CVF) on the ICF control has been researched in many papers. It is reported that the third-order LCL filter can be simplified to a first-order L filter when the CVF is used [10], [11], and the CVF can also improve the robustness of LCL active damping against the grid impedance for the ICF control [12]- [15]. However, although the CVF is helpful for the active damping of the LCL filter at the resonant frequency, the voltage feedforward loop is detrimental to the current control in low-frequency range, especially in weak grids [16], [17].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Novel Inverter-Side Current Control Method of $LCL$ -Filtered Inverters Based on High-Pass- Filtered Capacitor Voltage Feedforward

Zhou

2020

IEEE Access

View full text Add to dashboard Cite

LCL filters have been widely used as the interface between inverters and power grids, but damping methods must be taken to solve the resonance of LCL filters. Considering overcurrent protection and inherent active damping, this paper focuses on the inverter-side current feedback (ICF) control. Some literatures have proposed that the capacitor voltage feedforward (CVF) is beneficial to the stability of the ICF control. However, in practical applications, it is found that the ICF control with CVF mainly faces two problems. Firstly, the CVF can be seen as a positive feedback loop, and it tends to cause low-frequency oscillation, especially in weak grid. Secondly, low-frequency harmonics in the grid voltage can easily distort the grid-side current of the inverter, even though the inverter-side current has been regulated well. In order to solve these two problems simultaneously, this paper proposes a novel inverter-side current control method, which adds a high-pass filter into the CVF path. In this paper, the design process of the high-pass filter parameters is analyzed, and the specific voltage feedforward structure of the proposed method to avoid the inverter startup inrush current is also discussed in detail. Simulations in MATLAB/SIMULINK and experiments based on a 6.6 kW prototype have been utilized to verify the effectiveness of the proposed method. INDEX TERMS LCL filters, inverter-side current feedback, capacitor voltage feedforward, low-frequency oscillation, weak grid, high-pass filter.

show abstract

Section: Grid Voltage Harmonic Suppressionmentioning

confidence: 61%

Section: Grid Voltage Harmonic Suppressionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Novel Inverter-Side Current Control Method of $LCL$ -Filtered Inverters Based on High-Pass- Filtered Capacitor Voltage Feedforward

Zhou

2020

IEEE Access

View full text Add to dashboard Cite

show abstract

“…In a similar manner, when the 2ω 0 − ω p frequency components is considered, the power stage small signal model in stationary reference frame can be expressed as (19) where I p, 2ω 0 − ω p and D p, 2ω 0 − ω p are the phasors of the grid current and duty cycle responses at frequency 2ω 0 − ω p . The small signal model of the control loop in the dq frame is…”

Section: Equivalent Converter Impedance Model Considering Pll and Frementioning

confidence: 99%

“…Substituting (21) and 22into (20), and according to (19), we can obtain the coupling impedance for the response at…”

Section: Equivalent Converter Impedance Model Considering Pll and Frementioning

confidence: 99%

Effects on oscillation mechanism and design of grid‐voltage feedforward in grid‐tied converter under weak grid

Wang

Song

et al. 2019

IET Power Electronics

View full text Add to dashboard Cite

Grid-voltage feedforward control is widely used in grid-tied converters. The reported studies show that the gridvoltage feedforward may reduce the system stability margin, and may lead to oscillation problem in renewable power generation system. This study revisits the effect of voltage feedforward control on system stability and especially focuses on low frequency oscillation with impedance-based method. The low frequency oscillation usually happens in industry around 100 Hz and shows frequency coupling characteristics. A converter equivalent impedance which includes the effects of voltage feedforward and also covers the frequency coupling introduced by phase locked loop (PLL) is established. Based on the built impedance, the effect on oscillation mechanism with voltage feedforward and PLL is revealed. The results show that the voltage feedforward could increase the system stability margin and may be employed to improve the system stability. Then how to design an optimal proportional voltage feedforward control is demonstrated. Experimental results verify the theoretical analysis and the design of the proportional grid-voltage feedforward control.

show abstract

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

Wan

Ding

2021

Mathematical Problems in Engineering

View full text Add to dashboard Cite

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.

show abstract

Stability improvement of current control by voltage feedforward considering a large synchronous inductance of diesel generator

Cited by 3 publications

References 10 publications

A Novel Inverter-Side Current Control Method of $LCL$ -Filtered Inverters Based on High-Pass- Filtered Capacitor Voltage Feedforward

A Novel Inverter-Side Current Control Method of $LCL$ -Filtered Inverters Based on High-Pass- Filtered Capacitor Voltage Feedforward

Effects on oscillation mechanism and design of grid‐voltage feedforward in grid‐tied converter under weak grid

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

Contact Info

Product

Resources

About