A novel impedance modeling and stability analysis paradigm of microgrids consisting of virtual synchronous generators and constant power loads
Jiwei Ge
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
Search for more papers by this authorCorresponding Author
Yang Han
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
Correspondence
Yang Han, School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
Email: [email protected]
Search for more papers by this authorPing Yang
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
Search for more papers by this authorAmr S. Zalhaf
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
Electrical Power and Machines Engineering Department, Faculty of Engineering, Tanta University, Tanta, Egypt
Search for more papers by this authorJiwei Ge
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
Search for more papers by this authorCorresponding Author
Yang Han
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
Correspondence
Yang Han, School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
Email: [email protected]
Search for more papers by this authorPing Yang
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
Search for more papers by this authorAmr S. Zalhaf
School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
Electrical Power and Machines Engineering Department, Faculty of Engineering, Tanta University, Tanta, Egypt
Search for more papers by this authorAbstract
The application of virtual synchronous generators (VSGs) in power systems is gradually increasing to address the low inertia issue caused by the high penetration of renewable energy sources. Besides, the stability of microgrids (MGs) is threatened by constant power loads (CPLs) consisting of power electronic converters with closed-loop controllers. To investigate the stability of the MG composed of VSG and CPL, this paper analyzes the operational principles of VSG and CPL, revealing that only the bipolar switch logic function is suitable for establishing a closed-loop model if the output of the inner-loop controller is considered as the duty cycle of the PWM signal. Furthermore, the closed-loop impedance models of VSG and CPL were established in the dq frame. Impedance-based analysis results show that the MG is prone to oscillation in the mid-band. Therefore, the active power loop parameters of the VSG have a small impact on the stability of the MG, while the LC filter and inner loop controllers have a greater impact on the stability. Based on the oscillation mechanism and passivity theory, the impedance reshaping strategy for VSG and CPL is proposed. It is verified that the proposed control strategy can significantly improve the stability of the MG through the comparison of simulation results and theoretical analysis.
Open Research
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.
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