An Adaptive Inertia and Damping Control Strategy Based on Enhanced Virtual Synchronous Generator Model

Abstract

In modern converter-dominated power systems, total inertia is very variable and depends on the share of power generated by renewable-based converter-interfaced generation (CIG) at each specific moment. As a result, the limits required by the grid codes on the rate of change of frequency and its nadir or zenith during disturbances become challenging to achieve with conventional control approaches. Therefore, the transition to a novel control strategy of CIG with a grid-forming power converter is relevant. For this purpose, a control algorithm based on a virtual synchronous generator (VSG) is used, which simulates the properties and capabilities of a conventional synchronous generation. However, due to continuously changing operating conditions in converter-dominated power systems, the virtual inertia formed by VSG must be adaptive. At the same time, the efficiency of adaptive algorithms strongly depends on the used VSG structure. In this connection, this paper proposes an enhanced VSG structure for which the transfer function of the active power control loop was formed. With the help of it, the advantages over the conventional VSG structure were proven, which are necessary for the effective adaptive control of the VSG parameters. Then, the analysis of the impact of the VSG parameters on the dynamic response using the transient characteristics in the time domain was performed. Based on the results obtained, adaptive algorithms for independent control of the virtual inertia and the parameters of the VSG damper winding were developed. The performed mathematical modeling confirmed the reliable and effective operation of the developed adaptive control algorithms and the enhanced VSG structure. The theoretical and experimental results obtained in this paper indicate the need for simultaneous development and improvement of both adaptive control algorithms and VSG structures used for this purpose.

Aggregation frequency regulation strategy for wind and solar storage systems considering inertia adaptation

“…Based on the frequency stability index of the power system based on the virtual inertia of new energy, the inertia that the new energy unit should have can be derived from the index [3][4] .VSG module is to simulate the operation process of synchronous generator, establish the rotor equation of synchronous machine from the perspective of energy, output SMPWM wave, control the output characteristics of the converter, so that the new energy unit or load has the inertia, damping and other characteristics of synchronous unit, provide virtual inertia for power electronic equipment, and provide inertia support for the frequency stability of the system. Since there are a large number of distributed new energy sources in the distribution network, it is of great significance to study the parameter tuning of VSG model inertia adaptive in order to utilize distributed new energy sources [5][6] .In this paper, VSG inertia and damping coefficient adaptive strategy is designed, and the adaptive parameters are adjusted. According to the characteristics of Wind energy storage system based on three frequency dynamic indexes, the day-ahead scheduling control strategy is designed, and the experiment is carried out in IEEE4 system to compare the designed adaptive inertia day-ahead real-time scheduling control strategy with other frequency control strategies.…”