Novel Virtual Synchronous Generator Design With Dynamic Virtual Inertia and Bounded Frequency, Current and Voltage Characteristics

A grid current feedforward control method to suppress output current harmonic of virtual synchronous generator under distorted grid

Fuzzy-enhanced cooperative control of multiple virtual synchronous generators for grid-connected energy storage systems

Synchronization Stability Analysis of Grid-Tied Virtual Synchronous Generators During Asymmetrical Grid Faults

Synthetic Inertia Control for a Wind Turbine Generator Based on Event Size and Rotor Speed

Integration of DRL-driven edge computing for adaptive synthetic inertia allocation in grid-forming BESSs under spatial frequency variations

Renewable energy’s growing penetration erodes traditional power systems’ inherent dynamic symmetry—balanced inertia, damping, and frequency response. This paper proposes a self-adaptive virtual synchronous generator (VSG) control strategy for a photovoltaic hybrid energy storage system (PV-HESS) based on a radial basis function (RBF) neural network. The strategy establishes a dynamic adjustment framework for inertia and damping parameters via online learning, demonstrating enhanced system stability and robustness compared to conventional VSG methods. In the structural design, the DC-side energy storage system integrates a passive filter to decouple high- and low-frequency power components, with the supercapacitor attenuating high-frequency power fluctuations and the battery stabilizing low-frequency power variations. A small-signal model of the VSG active power loop is developed, through which the parameter ranges for rotational inertia (J) and damping coefficient (D) are determined by comprehensively considering the active loop cutoff frequency, grid connection standards, stability margin, and frequency regulation time. Building on this analysis, an adaptive parameter control strategy based on an RBF neural network is proposed. Case studies show that under various conditions, the proposed RBF strategy significantly outperforms conventional methods, enhancing key performance metrics in stability and dynamic response by 16.98% to 70.37%.

Virtual synchronous generator (VSG) technology introduces synthetic rotational inertia and damping into inverter-based systems, thereby enhancing regulation performance under grid-connected operation. However, the output characteristics of VSGs are strongly influenced by virtual inertia and damping. This paper develops a self-tuning inertia–damping coordination mechanism for VSGs. The coupling between virtual inertia and damping with respect to grid power quality is systematically investigated, and a power-angle dynamic response model for synchronous generators (SGs) under extreme operating conditions is established. Building on these results, an improved adaptive control strategy for the VSG’s virtual inertia and damping is proposed. The proposed strategy detects changes in frequency and load power, enabling adaptive tuning of virtual inertia and damping in response to system variations, thereby reducing frequency overshoot while accelerating the dynamic response. The effectiveness of the proposed strategy is validated by hardware-in-the-loop real-time simulations.

Inverter Based Resources (IBR) are gaining more popularity in modern power systems, leading to decrease in grid inertia. Hydropower Plants with rotating synchronous machines have been excellent source of inertia in existing grids. Adding a frequency converter between the generator and the grid in these hydropower plant would enable to run the hydropower in variable speed leading to enhanced efficiency and more flexibility in operation. These Variable Speed Hydropower Plant (VSHP), having the capability of anciliary services for grid support could be a potential solution for providing synthetic inertia to low-inertia power grids. However, there is a little research done on control of VSHP for grid support. This paper aims at implementing Non-Linear Model Predictive Controller (NLMPC) algorithm for optimal control of VSHPs, and the results are compared with classical PID control method. Explicit comparison under realistic operating condition and analysis of constraint handling capabilities and robustness of MPC have been performed. Advanced model based NLMPC successfully coordinated the hydraulic and electric systems having different time constants by implementing multi-objective optimization and upstream constraints satisfaction. Furthermore, the NLMPC has shown relatively better performance than the classical controllers even during the occurrence of an unanticipated grid-side disturbance. This paper is claimed to be an important work in control domain since it develops the control system for VSHPs using time-domain models which can offer better insights over the nonlinearities that exist within hydropower systems. Apart from the computational complexity, NLMPC is found to be viable for the control of VSHP since it ensured stable operation, as can be seen from the analysis of different operational cases studied implemented in this paper. The key takeaway from this paper is the potential of utilizing advanced model based optimal control strategy for coordination among complex dynamic systems of VSHP for different loading patters and disturbances. Also, the MPC has a scope of providing more robust grid support by addressing overloads and uncertainties during operation.

To address the insufficient adaptability of virtual synchronous generators (VSGs) under traditional fixed-value damping control in multiple application scenarios and the lack of regulatory flexibility in transient damping control with a fixed cutoff frequency, a transient damping-type VSG control strategy with flexibly adjustable cutoff frequency is proposed. The aim is to break through the regulatory limitations of the fixed cutoff frequency, quantify the inverse coordination relationship between the cutoff frequency and the equivalent damping coefficient, establish a dynamic adjustment mechanism of the cutoff frequency based on the system natural oscillation frequency, damping ratio, and power grid parameters, and clarify the value range from 0 to ωcmax as well as the real-time adaptation algorithm. First, the influence of damping on active power and frequency is analyzed through the VSG model. Second, combined with the characteristic analysis of different damping types, the advantages of transient damping in transient response capability under various operating conditions are derived. Furthermore, the role of the cutoff frequency in transient damping on output characteristics is specifically analyzed, a transient damping design method with flexibly adjustable cutoff frequency is proposed, and the value range of the cutoff frequency is calibrated. Finally, a hardware-in-the-loop experimental platform is established for experimental testing. The strategy effectively eliminates the output power deviation when the system frequency deviates, enhances the transient response capability of the VSG under different operating conditions, and exhibits superior output characteristics.

To address the issue that distributed renewable energy grid-connected Virtual Synchronous Generator (VSG) systems are prone to significant power and frequency fluctuations under changing operating conditions, this paper proposes a multi-parameter coordinated control strategy for VSGs based on a fusion framework of fuzzy logic and the Soft Actor–Critic (SAC) algorithm, termed Improved SAC-based Virtual Synchronous Generator control (ISAC-VSG). First, the method uses fuzzy logic to map the frequency deviation and its rate of change into a five-dimensional membership vector, which characterizes the uncertainty and nonlinear features during the transient process, enabling segmented policy optimization for different transient regions. Second, a stage-based guidance mechanism is introduced into the reward function to balance the agent’s exploration and stability, thereby improving the reliability of the policy. Finally, the action space is expanded from inertia–damping to the coordinated regulation of inertia, damping, and active power droop coefficient, achieving multi-parameter dynamic optimization. MATLAB/Simulink R2022b simulation results indicate that, compared with the traditional SAC-VSG and DDPG-VSG method, the proposed strategy can reduce the maximum frequency overshoot by up to 29.6% and shorten the settling time by approximately 15.6% under typical operating conditions such as load step changes and grid phase disturbances. It demonstrates superior frequency oscillation suppression capability and system robustness, verifying the effectiveness and application potential of the proposed method in high-penetration renewable energy power systems.

With the rapid development of new energy, high-proportion new energy power systems have significantly reduced inertia and voltage support capacity, facing severe stability challenges. Virtual Synchronous Generator (VSG) control, which simulates the inertia and voltage source characteristics of traditional synchronous generators, enables friendly grid connection of new energy converters and has become a key technology for large-scale new energy applications. This paper addresses two key issues in low-voltage ride through (LVRT) of grid-forming converters under VSG control: (1) converter overcurrent suppression during LVRT; (2) reduced reactive power support due to retaining voltage-reactive power droop control during faults. It proposes an adaptive virtual impedance-based overcurrent suppression method and a frozen reactive power–voltage droop-based reactive support method. Based on the converter’s mathematical model, a DIgSILENT/PowerFactory simulation model is built. Time-domain simulations verify the converter’s operating characteristics and the improved LVRT strategy’s effect, providing theoretical and technical support for large-scale applications of grid-forming converters.

In the case of small disturbances in the power grid, virtual synchronous generators (VSGs) often exhibit active power steady-state errors and significant frequency overshoot, and it is difficult to balance the reduction of active power steady-state errors and the mitigation of frequency overshoot. This paper proposes an improved control method based on active power differential compensation (APDC). First, an active power differential compensation loop is introduced, effectively addressing the issues of active power steady-state deviation and frequency overshoot caused by fixed parameters in the traditional VSG. Secondly, by incorporating a fuzzy logic control (FLC) algorithm, an adaptive PID tuning strategy is proposed as a replacement for the traditional fixed virtual inertia; the PID parameters are dynamically adjusted in real time according to the power–angle deviation and its rate of change, thereby enhancing the small-disturbance dynamic performance of the VSG. Finally, MATLAB R2020b/Simulink simulations and StarSim hardware-in-the-loop simulations validate the effectiveness and accuracy of the proposed control strategy. Simulation results indicate that, compared to traditional control strategies, under peak regulation conditions, the frequency overshoot is reduced by approximately 4.4%, and the active power overshoot is reduced by approximately 5%; under frequency regulation conditions, the frequency overshoot is reduced by approximately 0.26%, and the power overshoot is reduced by approximately 12%.

Large-scale renewable power supply system design for remote hydrogen production is a challenging task due to the 100% power electronics sending-end subsystem. The proper grid-forming strategy for a sending-end system to achieve large-scale remote hydrogen production still remains a research gap. This study first designs two grid-forming strategies for the concerned renewable power supply system, with one being based on virtual synchronous generator (VSG) and another one being based on V/f control. Then, the impedance analysis is carried out for ensuring the small-signal stable operation of the sending-end system including wind power plant and PV plant. Numerical simulation results implemented on PSCAD verify that the VSG-based grid-forming strategy configured on the sending-end modular multilevel converter (MMC) station of the MMC-based high-voltage direct-current (HVDC) link has a larger transient stability margin. Hence, the MMC-HVDC-based grid-forming strategy is a better choice for the power supply of large-scale remote hydrogen production. The enhanced stability margin ensures more robust operation under disturbances, which is critical for maintaining continuous power supply to large-scale electrolyzers.

In the photovoltaic storage power generation system controlled by the traditional virtual synchronous generator (VSG), when the photovoltaic source power fluctuates, the energy storage device will charge and discharge frequently to suppress the fluctuating power. In order to decrease the charge and discharge frequency of the energy storage device and alleviate the dependence of the VSG system on the energy storage device, an improved control strategy for the photovoltaic storage VSG system is proposed. The relationship between frequency variation and DC voltage deviation of the system is studied. The virtual synchronous control unit based on DC voltage control frequency is designed to replace the active power frequency control unit of the traditional VSG, which achieves the maximum power grid connection and inertial support of the VSG system. The power control of the energy storage device is implemented based on the droop characteristic, which improves the flexibility of energy storage device power control. The DC voltage stability control scheme is designed to keep the voltage within a reasonable range when the system is working normally. The experimental results verify the effectiveness of the proposed improved control strategy.

DC line power flow coordinated control of MMC-MTDC with virtual synchronous generator

Abstract The grid-forming converter(GFM) based on virtual synchronous generator(VSG) control has been widely applied due to its inertia and damping support capabilities. However, in a multi-level parallel system, the control characteristics become more complex. This may lead to new stability issues. In order to explore the stability of GFM parallel systems, firstly, a small-signal model of the GFM multi-machine parallel system was constructed, and the influence of different control parameters on the system stability was studied through the eigenvalue analysis method. Secondly, an adaptive control parameter strategy based on the improved particle swarm optimization algorithm was established, which enhanced the stability of the dual-machine parallel system. Finally, the correctness of the strategy was verified through the simulation built with MATLB\simulink.

Design-oriented analysis of virtual synchronous generator control for asymptotic stability in grid-forming converters

Enhanced active power response control for virtual synchronous generators: An active power compensation combined with feedback damping strategy

Structure-constrained output feedback synthetic inertia decentralized control for two area power system