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The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System.

Liu YP, Liang HP, Gao ZK - PLoS ONE (2015)

Bottom Line: In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side.Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method.In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.

View Article: PubMed Central - PubMed

Affiliation: School of Electrical and Electronic Engineering, North China Electric Power University, Baoding, Hebei Province, 071003, China.

ABSTRACT
In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.

No MeSH data available.


The AOK TFR result of DC current signal for PI method.
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pone.0130135.g019: The AOK TFR result of DC current signal for PI method.

Mentions: The adaptive optimal kernel time-frequency representation can be expressed asP(t,f)=∬A(t,τ,υ)Φ(τ,υ)e−j2π(tυ+τf)dτdυ(28)where Φ(τ,υ) is a kernel function for generating AOK TFR,Φ(τ,υ)=e−r2/2σ2(ψ)(29)σ(Ψ) controls the extension of Gaussian kernel at Ψ direction, and r2 = τ2+υ2, where τ and υ are the time-delay and frequency shift, respectively. A(t,τ,υ) is a window signal which can be defined asA(t,τ,υ)=∫s*(u−τ2)⋅ω*(u−t−τ2)⋅s(u+τ2)⋅ω(u−t−τ2)⋅ejυudu(30)More details about the WVD method and AOK TFR method see Ref. [49–50]. The AOK time frequency representation can effectively suppress the cross-term while keeping a high time-frequency concentration. From the above definitions we could know that, WVD and AOK TFR give a mapping from time domain to time-frequency domain, which means it makes analyzing signals in both time and frequency domain possible. The corresponding WVD results for our proposed method and PI method are shown in Figs 11 and 12, Figs 13 and 14, Figs 15 and 16, Figs 17 and 18, respectively. The corresponding AOK TFR results for our proposed method and PI method are shown in Figs 19 and 20, Figs 21 and 22, Figs 23 and 24, Figs 25 and 26, respectively.


The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System.

Liu YP, Liang HP, Gao ZK - PLoS ONE (2015)

The AOK TFR result of DC current signal for PI method.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476685&req=5

pone.0130135.g019: The AOK TFR result of DC current signal for PI method.
Mentions: The adaptive optimal kernel time-frequency representation can be expressed asP(t,f)=∬A(t,τ,υ)Φ(τ,υ)e−j2π(tυ+τf)dτdυ(28)where Φ(τ,υ) is a kernel function for generating AOK TFR,Φ(τ,υ)=e−r2/2σ2(ψ)(29)σ(Ψ) controls the extension of Gaussian kernel at Ψ direction, and r2 = τ2+υ2, where τ and υ are the time-delay and frequency shift, respectively. A(t,τ,υ) is a window signal which can be defined asA(t,τ,υ)=∫s*(u−τ2)⋅ω*(u−t−τ2)⋅s(u+τ2)⋅ω(u−t−τ2)⋅ejυudu(30)More details about the WVD method and AOK TFR method see Ref. [49–50]. The AOK time frequency representation can effectively suppress the cross-term while keeping a high time-frequency concentration. From the above definitions we could know that, WVD and AOK TFR give a mapping from time domain to time-frequency domain, which means it makes analyzing signals in both time and frequency domain possible. The corresponding WVD results for our proposed method and PI method are shown in Figs 11 and 12, Figs 13 and 14, Figs 15 and 16, Figs 17 and 18, respectively. The corresponding AOK TFR results for our proposed method and PI method are shown in Figs 19 and 20, Figs 21 and 22, Figs 23 and 24, Figs 25 and 26, respectively.

Bottom Line: In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side.Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method.In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.

View Article: PubMed Central - PubMed

Affiliation: School of Electrical and Electronic Engineering, North China Electric Power University, Baoding, Hebei Province, 071003, China.

ABSTRACT
In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.

No MeSH data available.