Active and Reactive Power Control Strategy for Grid-Connected Six-Phase Generator by using Multi-Modular Matrix Converters

Systemics, Cybernetics And Informatics
2016 unpublished
This paper proposes an active and reactive power control strategy based on predictive control approaches applied to grid-connected renewable energy systems. To accomplish this a multi-modular matrix converter topologies are used in combination with a simple but efficient grid synchronization strategy. The theoretical performance analysis is performed considering a six-phase wind energy generator system interconnected with the grid. Results based on a MATLAB/Simulink simulation environment are
more » ... scussed and the most relevant characteristics of the proposed control technique are highlighted considering the total harmonic distortion and the mean squared error as a parameters of performance. In the last years the interest in power generation from renewable energy sources has experienced a significant growth, mainly justified by the reduced environmental impact generated. Renewable energy systems (RES), such as solar photovoltaic (PV), micro-hydraulic and wind energy systems are widely used as an alternative to the traditional systems. A very active research area in the field of RES are focused in the multiphase wind energy generator (MWEG) systems [1], [2]. In particular, MWEG systems with multiple three-phase windings are very convenient for wind turbine (WT) applications, due to important aspects especially for high-power safety-critical applications such as performance, reliability, smooth torque and partition of power [3]. In MWEG, the six-phase wind energy generator (SpWEG) with two sets of three-phase stator windings spatially shifted by 30 electrical degrees and isolated neutral points is probably one of the most widely discussed topology with fully rated back-to-back converter system to grid-connected applications [4]-[6]. Consequently with the development of multiphase topologies and drives, recent research efforts have been focused in the development of a flexible power interface based on a modular architecture capable to interconnecting different renewable energy sources and load, including energy storage systems to the electrical grid. These efforts converge in the multi-modular matrix converter (MMC) topologies whose the main feature is the ability to provide a three-phase sinusoidal voltages with variable amplitude and frequency using fully controlled bi-directional electronic switches without the use of energy storage elements [7]. These characteristics makes plausible the use of MMC in applications where are required high power density and compact converters such as SpWEG systems, constituting an attractive alternative if it is compared with conventional converter topologies [8], [9]. The main contribution of this paper comparing with the previous works will focus on a theoretical performance analysis of a MMC combined with a SpWEG scheme in order to ensure an efficient active and reactive power control from the generator side to the grid side. Each module of the MMC architecture are connected in cascade to the independent three-phase windings of the SpWEG. A model-based predictive control (MPC) technique is used to predict the effects of future control actions in order to minimize a defined cost function. The control criterion will be the active and reactive power control. This paper is organized as follows: Section 2 describes the mathematical model of the MMC. Section 3 presents a detailed description of the MPC control strategy. Section 4 discusses the simulation results and a performance analysis of the proposed predictive control technique using the total harmonic distortion (THD) and the mean square error (MSE) as a parameters of performance. Finally, the main remarks are summarized in Section 5. 2. POWER CONVERSION MODEL The proposed topology consists of two three-phase matrix converter (MC) modules connected to the SpWEG by using a passive (LC) input filter and then connected to the grid by an output filter, as it was shown in Fig. 1. Each one of