Damping Formation Mechanism and Damping Injection of Virtual Synchronous Generator Based on Generalized Hamiltonian Theory

Abstract

Invertor as a virtual synchronous generator (VSG) to provide virtual inertia and damping can improve the stability of a microgrid, in which the damping is one of the fundamental problems in dynamics. From the view of the Hamiltonian dynamics, this paper researches the damping formation mechanism and damping injection control of VSG. First, based on the energy composition and dynamic characteristics of VSG, the differential equations system of VSG is established and is transformed into the generalized Hamiltonian system. Second, the effects of the three parameters of VSG, the damping coefficient D, active power droop coefficient, and time constant of excitation TE on damping characteristics are researched from a dynamic perspective, and simulation research is carried out with an isolated microgrid. Lastly, the control design method of Hamiltonian structure corrections used to add the damping factor and design the equivalent control inject damping to improve the stability of the isolated microgrid. Research shows that the voltage and frequency stability of the isolated microgrid can be effectively improved by selecting three key parameters of VSG and damping injection control. The innovations of this paper are 1. The Hamiltonian model of the inverter is deduced and established by taking the inverter as a virtual generator. 2. Based on the Hamiltonian model, damping characteristics of inverter in the microgrid are studied. 3. Hamiltonian structure correction method is applied to the inverter, and equivalent damping injection is designed to improve the stability of the microgrid.

Extended State Observer Based-Backstepping Control for Virtual Synchronous Generator

“…The world is witnessing a rapid expansion in renewable energy sources, as well as a larger share of electrical energy produced from renewable sources as grid-connected or isolated systems, which makes the operation and stability control of distributed generation units and their grid connectionsparamount [4]. Small networks are an electrical system for transferring electrical energy from multiple types of DGs connected together to form a microgrid, and they provide a way to integrate these DGs into the power grid, which is developed with the technology of renewable energies and distributed generation [4,5], where the power electronic devices play a very important role in this discipline [6]. As is well known, DGs based on power electronic devices, such as solar panels, wind turbines, fuel cells, and so on, have low inertia and damping properties, which have an impact on system stability and dynamic performance, making the system more susceptible to perturbations [5].…”

“…Due to the lack of grid inertia and damping support, the stable operation of the power grid has been challenged as the penetration of power electronic devices based on DGs into the power grid has increased. In order to solve these issues, the virtual synchronous generator, where the power electronic inverter is controlled to replicate the properties of traditional synchronous generators, was proposed as a promising strategy [6][7][8].…”

“…Many researchers and academics have attempted to overcome the abovementioned challenges by modeling the inverter power component and adding rotor swing equations to offer virtual inertia, allowing the inverter to work as a VSG [6,[8][9][10]. Several configurations for VSG systems have been introduced worldwide since 2008 [6,11].…”

“…Many researchers and academics have attempted to overcome the abovementioned challenges by modeling the inverter power component and adding rotor swing equations to offer virtual inertia, allowing the inverter to work as a VSG [6,[8][9][10]. Several configurations for VSG systems have been introduced worldwide since 2008 [6,11]. Recently, various control methods have been applied for VSG to overcome the microgrid stability and ensure a smooth transition during disruption, such as particle swarm optimization, including the voltage angle deviations of generators, which was suggested in [12], oscillation damping method of VSG using pole placement, proposed in [13], a hybrid control method of the inertia and the damping island microgrids [14,15], imitation excitation control method [16], improved fuzzy logic controller [17][18][19][20][21], and so on.…”

Detecting safe operational regimes of synchronous motor‐generator pair for wind integration: A non‐linear perspective

“…Range of damping co-efficient values that bring out stable operating region for power angle is studied with addition of virtual inertia and power electronic control in refs. [21][22][23][24][25]. The SMIB system is modelled using non-linear equations by capturing the dynamics of power angle and voltage for such studies [26].…”