Direct energy balance based active disturbance rejection control for coal-fired power plant

Li Sun; Qingsong Hua; Donghai Li; Lei Pan; Yali Xue; Kwang Y Lee

doi:10.1016/j.isatra.2017.06.003

Direct energy balance based active disturbance rejection control for coal-fired power plant

ISA Trans. 2017 Sep:70:486-493. doi: 10.1016/j.isatra.2017.06.003. Epub 2017 Jul 25.

Authors

Li Sun¹, Qingsong Hua², Donghai Li³, Lei Pan⁴, Yali Xue⁵, Kwang Y Lee⁶

Affiliations

¹ Key Lab of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China. Electronic address: sunli12@seu.edu.cn.
² School of Mechanical and Electrical Engineering, Qingdao University, Ningxia Road 308, 266071 Qingdao, China.
³ State Key Lab for Power Systems, Tsinghua University, Beijing, 100084, China. Electronic address: lidongh@tsinghua.edu.cn.
⁴ Key Lab of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China.
⁵ State Key Lab for Power Systems, Tsinghua University, Beijing, 100084, China.
⁶ Department of Electrical & Computer Engineering, Baylor University, Waco, TX 76798, USA.

PMID: 28754413
DOI: 10.1016/j.isatra.2017.06.003

Abstract

The conventional direct energy balance (DEB) based PI control can fulfill the fundamental tracking requirements of the coal-fired power plant. However, it is challenging to deal with the cases when the coal quality variation is present. To this end, this paper introduces the active disturbance rejection control (ADRC) to the DEB structure, where the coal quality variation is deemed as a kind of unknown disturbance that can be estimated and mitigated promptly. Firstly, the nonlinearity of a recent power plant model is analyzed based on the gap metric, which provides guidance on how to set the pressure set-point in line with the power demand. Secondly, the approximate decoupling effect of the DEB structure is analyzed based on the relative gain analysis in frequency domain. Finally, the synthesis of the DEB based ADRC control system is carried out based on multi-objective optimization. The optimized ADRC results show that the integrated absolute error (IAE) indices of the tracking performances in both loops can be simultaneously improved, in comparison with the DEB based PI control and H_∞ control system. The regulation performance in the presence of the coal quality variation is significantly improved under the ADRC control scheme. Moreover, the robustness of the proposed strategy is shown comparable with the H_∞ control.

Keywords: Active disturbance rejection control; Boiler-turbine unit; Direct energy balance; Extended state observer; Multi-objective optimization.