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This paper proposes the predictive control with the discrete space-vector modulation (DSVM) for Vienna rectifier connecting to the permanent magnet synchronous generator (PMSG) of the wind turbine system (WTS). Since Vienna rectifier has the special operation principle, Vienna rectifier generates only the feasible eight voltage vectors, which can be a candidate vector for the predictive control, depending on the sign of the input currents. In the proposed predictive control, the feasible voltage vectors are extended from 8 to 19 consisting the 8 original voltage vectors and 11 virtual voltage vectors by using the DSVM for improving the current quality related to the torque ripple, vibration, and noise, and the neutral-point voltage balance with low voltage ripple is guaranteed by using the offset value calculated based on the model of two dc-link capacitors in Vienna rectifier. The scheme for reducing calculation burden is applied in selecting the candidate vector. In addition, the limited operation range for the maximum torque per ampere control of PMSG connected to Vienna rectifier is analyzed. The performance of the proposed predictive control with DSVM for Vienna rectifier with PMSGs is verified in simulation and experiment. [ABSTRACT FROM AUTHOR]

This article proposes three-phase cascaded multilevel rectifiers for wind energy conversion system applications. These configurations operate as machine-side converters and play an essential role in the integration of wind power generation units. The proposed rectifiers are connected to a permanent magnet synchronous machine by an open-end winding arrangement, making the ac–dc conversion of the power delivered with high-power factor operation. Their structures are composed of a combination of a converter based on Vienna rectifiers and one H-bridge per phase with a floating capacitor. Compared with the conventional configurations, the proposed ones provide sinusoidal currents with lower harmonic distortion using, proportionally, a fewer number of controlled switches. Furthermore, they can operate with a lower switch blocking voltage. These features make them attractive options for industrial applications due to their good performance, providing an interesting cost–benefit. The system model, pulsewidth modulation technique, capacitor voltage balancing, and control strategy are detailed. Computer simulations and experimental tests are provided in order to validate their feasibility. [ABSTRACT FROM AUTHOR]

This article proposes three-phase configurations for wind energy conversion system applications. The proposed topologies are based on Vienna rectifiers and they have a reduced number of controlled switches, which may allow reducing size and costs. Despite they can work with other arrangements, the proposed structures operate at an open-end winding configuration in this article, providing some benefits over the traditional ones. Compared to the conventional topology, the proposed ones provide a better power quality employing, proportionally, a fewer number of controlled switches, offering a higher levels-per-switch ratio. Moreover, they can also operate at a lower switch blocking voltage. These features offer an interesting cost–benefit and make them attractive options to industry applications. The system model, modulation technique, and control strategy are discussed. Simulation and experimental results are provided in order to validate their performance and feasibility. [ABSTRACT FROM AUTHOR]

Neutral-point (NP) voltage imbalance is an inherent issue of three-level converters. The alternating input current distortion is generated by using the conventional discontinuous pulsewidth modulation (DPWM) scheme without NP voltage balance control. In this article, the deviation vector between the synthesis vector and the reference vector, which is the fundamental cause of alternating input current distortion under NP voltage unbalance conditions, is revealed. Then, by optimizing the subsector division and the switching state sequence, a dynamic-space-vector DPWM (DSV-DPWM) is proposed to eliminate the deviation vector. Further, the comparisons of the proposed DSV-DPWM, the conventional DPWM, and an existing triangle carrier-based DPWM (TCB-DPWM), are addressed. Finally, a 10-kW prototype was built to verify the effectiveness of the proposed DSV-DPWM scheme. Experimental results show that, compared with the conventional DPWM scheme and the TCB-DPWM scheme, both the current THD performance and efficiencies can be significantly improved by the proposed DSV-DPWM scheme under unbalanced NP voltage conditions. [ABSTRACT FROM AUTHOR]

Compared with continuous pulsewidth modulation (PWM), discontinuous PWM (DPWM) is a preferred solution in high-frequency Vienna-type rectifiers due to its inherent characteristics of less commutation number and higher efficiency. In this article, redundant clamping modes at the same subsector with opposite effects on the neutral point (NP) voltage are presented. Then, a modified DPWM (MDPWM) scheme is proposed to regulate the NP voltage by using redundant clamping modes. Thus, the NP voltage can be controlled in each switching period to lower the NP voltage fluctuation. The implementation of the proposed MDPWM is given with variable power factors analysis. Further, the switching loss comparison of conventional space vector PWM (SVPWM), hybrid DPWM (HDPWM), and proposed MDPWM is presented as well. A simulation model was built to verify the proposed NP voltage balance with different modulation indices and variable power factors. Finally, a 10-kW prototype is built to evaluate the proposed MDPWM scheme at conversion efficiency and current total harmonic distortion (THD). Experimental results and analysis show that comparing conventional SVPWM and HDPWM, the efficiency of MDPWM is the highest. The THD of DPWM is slightly higher than that of SVPWM, and it is only 2.5% at rated output power. [ABSTRACT FROM AUTHOR]

Vienna rectifier, which is a nongenerative-boost-type rectifier, is widely used in industrial applications, such as wind turbine systems. However, the Vienna rectifier will face the challenge of reducing common-mode voltage (CMV), maintaining the sinusoidal input currents, and balancing neutral-point (NP) voltage in practice. As these issues are mutually coupled, the conventional space vector modulation (SVM) and various types of enhanced schemes cannot solve these problems properly, especially under nonunity power factor operation. To overcome these limitations, a two-layer pulsewidth modulation scheme through vector selection is developed. In the first layer of the proposed strategy, the NP voltage oscillations are mitigated by adjusting the switching sequence and dwell time of large, medium, small, and zero vectors with reduced CMV as the same in large, medium, and zero vector modulation. In the second layer of the proposed strategy, the switching states are reselected, and the dwell times are real time adjusted to eliminate the distortions in input currents. Through the aforementioned two-layer control method, CMV reduction, input current distortion elimination, and NP voltage balancing in Vienna rectifier can be realized simultaneously. The correctness and effectiveness of the proposed SVM method are verified by the experiment. [ABSTRACT FROM AUTHOR]