Nady Rocha

Single-Phase to Three-Phase Power Converters: State of the Art

Single-phase to three-phase conversion using power electronics converters is a well-known technology, especially when the configurations and control strategies already established in the technical literature are considered. Regarding the configurations conceived over the years, it can be observed two main tendencies: 1) configurations with a reduced number of components; and 2) configurations with an increased number of components. The search for topologies with a reduced number of components was the trend over a long period of time. This can be, in part, explained by the high cost of the power switch when compared to the capacitor used in the dc-link bus. Then, the converter leg was sometimes substituted for the midpoint capacitor. However, as far as the price of the semiconductor was going down, such tendency has been changed, and now the configurations with an increased number of components do appear as an interesting option, especially in terms of reliability, efficiency, and distortions improvement. A comprehensive review of the two possibilities (reduced and increased number of components) has been considered in this paper. Also, the single-phase to three-phase ac-ac direct conversion configurations and those which aim to reduce the dc-link voltage fluctuation have been included. The goal of this paper is to provide a complete range on the status of single-phase to three-phase power conversion technologies to professionals and researchers interested in this topic.

Single-Phase to Three-Phase Drive System Using Two Parallel Single-Phase Rectifiers

This paper proposes a single-phase to three-phase drive system composed of two parallel single-phase rectifiers, a three-phase inverter, and an induction motor. The proposed topology permits to reduce the rectifier switch currents, the harmonic distortion at the input converter side, and presents improvements on the fault tolerance characteristics. Even with the increase in the number of switches, the total energy loss of the proposed system may be lower than that of a conventional one. The model of the system is derived, and it is shown that the reduction of circulating current is an important objective in the system design. A suitable control strategy, including the pulsewidth modulation technique (PWM), is developed. Experimental results are presented as well.

Single-Phase to Three-Phase Universal Active Power Filter

In this paper, a universal active power filter is proposed for harmonic and reactive power compensation in the single-phase to three-phase systems. The proposed configuration solves a typical problem found in remote (or rural) applications, where only a single-phase grid is available and there is a demand to supply three-phase loads. A suitable control strategy is presented to regulate the load voltage, the power factor, and to minimize the voltage and current harmonics simultaneously. Simulated and experimental results are also presented.

Reversible AC Drive Systems Based on Parallel AC–AC DC-Link Converters

In this paper, two reversible single-phase-to-three-phase ac drive systems are proposed. They are composed of an induction motor fed by two parallel single-phase-to-three-phase dc-link converters without isolation transformers. Suitable modeling and control strategy of the systems based on odq approach, including the unbalanced case, are developed. The proposed topologies permit reducing the harmonic distortion and presents fault tolerance characteristics. Even if the number of switches is increased, the total energy loss of the proposed systems can be lower than that of a conventional one. It is shown that the reduction of the circulating current is an important objective for the system design. A single-phase-to-three-phase dc-link converter generalization has been proposed as well. Simulated and experimental results are presented.

Six-Phase Machine Drive System With Reversible Parallel AC–DC–AC Converters

This paper proposes a reversible six-phase machine drive system. It is composed of two parallel three-phase to three-phase dc-link converters without isolation transformers. The proposed topology permits one to reduce the harmonic distortion in the input converter and decreases the power processed by converter switches. Furthermore, the proposed configuration can guarantee the feasibility of the system when high-power applications are considered. The model and the control strategy have been developed. The simulation and experimental results are presented.

AC-AC single-phase DC-link converter with four controlled switches

An unidirectional single-phase to single-phase component minimized dc-link converter is discussed in this paper. It is composed of one unidirectional rectifier and one bidirectional inverter, using only four controlled switches. Suitable modeling and control strategy of the system, including a synchronization method, are proposed. The synchronization method, associated with the PWM command, guarantees a sinusoidal input current with the same phase angle of the input converter voltage. In this approach, the output converter voltage is also in synchronization with the grid. Proposed method eliminates zero-crossing distortion caused by the use of diodes, as well. Additionally, the control strategy permits the converter to operate with same dc-link voltage value required for the conventional six-switch converter. Simulated and experimental results are presented.

Suitable Single-Phase to Three-Phase AC–DC–AC Power Conversion System

This paper presents a single-phase to three-phase power conversion system with parallel rectifier and series inverter to cope with single-phase to three-phase asymmetry. Such converter guarantees both reduction in the input current processed by rectifier circuit and reduction of the output voltage processed by inverter circuit. It is worth to mention that, in spite of proposing a topology with features no longer observed in the technical literature, this paper presents a comprehensive model of the proposed converter, modulation strategy and a general comparison with the conventional configuration. Simulated and experimental results are also presented.

Synchronization method for asymmetrical bridgeless boost rectifier

In this paper a synchronization method and a compatible PWM strategy for the asymmetrical bridgeless boost rectifier are proposed. In this method the grid current is forced to have the same phase angle as the voltage generated by the rectifier. The proposed method eliminates zero-crossing distortion caused by the use of diodes, thus reducing the harmonic distortions of input current. Simulated and experimental results are presented.

Shunt Active Power Filter With Open-End Winding Transformer and Series-Connected Converters

This paper presents a shunt active power filter based on the concept of open-end winding (OEW) transformers. The proposed configuration is constituted of two converters with three legs each series connected throughout a three-phase OEW transformer. Model PWM strategy and control scheme are presented as well. The main advantage of the proposed system lies on the multi-level waveform generation, which allows reduction of either harmonic distortions or switching losses. This proposed topology is suitable for medium voltage (MV) distribution systems. Simulation and experimental results validate the theoretical study.

AC-DC-AC six-phase machine drive system based on single-phase bridge converters

This paper presents an ac-dc-ac reversible six-phase machine drive system. It is composed of single-phase bridge converters connected in series in the grid side and single-phase bridge converters connected at the machine phase terminals. The proposed topology eliminates the input isolation transformers and reduces the power processed by converter switches and the harmonic distortion in the grid side. The model and the control strategy have been developed. Simulation and experimental results are presented.