The paper presents the method for multicriteria design of a synchronous generator voltage regulator. The results of the voltage regulator polyoptimisation are compromise sets for a classic controller of type PI and fuzzy logic controller of type Takagi-Sugeno-Kang. A genetic algorithm is used to solve the polyoptimisation problem.

A microgrid is an appropriate concept for urban areas with high penetration of renewable power generation, which improves the reliability and efficiency of the distribution network at the consumer premises to meet various loads such as domestic, industrial, and agricultural types. Microgrids comprising inverter-based and synchronous generator-based distribution generators can lead to the instability of the system during the islanded mode of operation. This paper presents a study on designing stable microgrids to facilitate higher penetration of solar power generation into a distribution network. Ageneralized small signal model is derived for a microgrid with static loads, dynamic loads, energy storages, solar photovoltaic (PV) systems, and diesel generators, incorporating the features of dynamic systems. The model is validated by comparing the transient curves given by the model and a transient simulator subjected to step changes. The result shows that full dynamic models of complex systems of microgrids can be built accurately, and the proposed microgrid is stable for all the considered loading situations and solar PV penetration levels according to the small signal stability analysis.

In this paper, dynamic response improvement of the grid connected hybrid system comprising of the wind power generation system (WPGS) and the photovoltaic (PV) are investigated under some critical circumstances. In order to maximize the output of solar arrays, a maximum power point tracking (MPPT) technique is presented. In this paper, an intelligent control technique using the artificial neural network (ANN) and the genetic algorithm (GA) are proposed to control the MPPT for a PV system under varying irradiation and temperature conditions. The ANN-GA control method is compared with the perturb and observe (P&O), the incremental conductance (IC) and the fuzzy logic methods. In other words, the data is optimized by GA and then, these optimum values are used in ANN. The results are indicated the ANN-GA is better and more reliable method in comparison with the conventional algorithms. The allocation of a pitch angle strategy based on the fuzzy logic controller (FLC) and comparison with conventional PI controller in high rated wind speed areas are carried out. Moreover, the pitch angle based on FLC with the wind speed and active power as the inputs can have faster response that lead to smoother power curves, improving the dynamic performance of the wind turbine and prevent the mechanical fatigues of the generator.

Wind energy has achieved prominence in renewable energy production. There fore, it is necessary to develop a diagnosis system and fault-tolerant control to protect the system and to prevent unscheduled shutdowns. The presented study aims to provide an experimental analysis of a speed sensor fault by hybrid active fault-tolerant control (AFTC) for a wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG). The hybrid AFTC switches between a traditional controller based on proportional integral (PI) controllers under normal conditions and a robust backstepping controller system without a speed sensor to avoid any deterioration caused by the sensor fault. A sliding mode observer is used to estimate the PMSG rotor position. The proposed controller architecture can be designed for performance and robustness separately. Finally, the proposed methodwas successfully tested in an experimental set up using a dSPACE 1104 platform. In this experimental system, the wind turbine with a generator connection via a mechanical gear is emulated by a PMSM engine with controled speed through a voltage inverter. The obtained experimental results show clearly that the proposed method is able to guarantee service production continuity for the WECS in adequate transition.

Different from the synchronization mechanism of synchronous generators, the non-synchronous generators must be synchronized with the grid through a controller. Generally, the virtual synchronous generator (VSG) control strategy is adopted for this purpose. In view of the current situation, where the control loops are not comprehensively considered in the research of the synchronization stability of the VSG, this paper considers multiple control loops, such as active frequency loops, virtual governors, power filters and current constraint control, to establish the mathematical model of the VSG and infinite system. On this basis, the correlation formula between power angle difference and control parameters is deduced. Adopting the phase plane method, the influence of different control loops and their parameters on the transient synchronization stability is analyzed. Finally, a setting principle of the frequency modulation coefficient of virtual governors is proposed, which not only meets the response speed of control systems, but also has good control performance.

Large synchronous generators are of high importance for the stability of power systems. They generate the frequency of the system and stabilize it in case of severe grid faults like trips of large in-feeders or loads. In distributed energy systems, in-feed via inverters will replace this generation in large parts. Modern inverters are capable of supporting grid frequency during severe faults by different means on the one hand. On the other hand, higher Rates of Change of Frequency (RoCoF) after incidents need to be accustomed by future systems. To be able to analyse the RoCoF withstand capability of synchronous or induction generators, suitable models need to be developed. Especially the control and excitation system model need enhancements compared to models proposed in standards like IEEE Std 421.5. This paper elaborates on the necessary modelling depth and validates the approach with example results.

Three synchronous machine models representing three precision levels (complete, reduced and static), implemented in a virtual synchronous generator (VSG)-based industrial inverter, are compared and discussed to propose a set of tests for a possible standardization of VSG-based inverters and to ensure their “grid-friendly” operation in the context of isolated microgrids. The models and their implementation in the microcontroller of an industrial inverter (with the local control) are discussed, including the usability of the implementation with large-scale developments constraints in mind. The comparison is conducted based on existing standards (for synchronous machines and diesel generators) in order to determine their needed evolution, to define the requirements for future grid-friendly inverter-based generators, notably implementing a VSG solution.