E. C. dos Santos

Reduced Switch Count Multiple Three-Phase AC Machine Drive Systems

In this paper, two three-phase ac drive systems with reduced number of components, named configurations and , are investigated. Configuration uses multiple two-leg voltage source inverters in which all inverters share an extra-leg. Configuration also employs multiple two-leg inverters but in this case the inverters share the midpoint of a capacitor bank in the dc-link, instead. These configurations are compared to configuration that employs multiple three-leg inverters. The main characteristics of the machine drive systems are presented together with selected experimental results that demonstrate the feasibility of the proposed configurations.

Digital-Scalar PWM Approaches Applied to Four-Leg Voltage-Source Inverters

In this paper, we present two modulation schemes for generating unbalanced voltages by means of four-leg voltage-source inverters. The first modulation is an extended scheme of a digital-scalar pulsewidth modulation previously proposed for controlling three-leg inverters. The second one is based on the decomposition of the voltage reference signals into their symmetrical components. The schemes are compared theoretically by simulations and experimental results. As a consequence, we find out a total equivalence between the two modulations despite their different conceptions. The fundamentals of both techniques and a mathematical proof of their equivalence are unfolded. Also, the performances of the techniques with respect to the harmonic distortion and power switching loss are discussed. The results show that the techniques are effective.

Single-Phase-Input Reduced-Switch-Count AC–AC Drive Systems

In this paper, two AC-AC reduced-switch-count drive systems for single- to three-phase applications are proposed. Both drive systems provide bidirectional power flow and power factor control. The operating principles of the topologies are presented, and a control strategy is proposed in order to reduce the DC-link voltage required by the converters. Moreover, the proposed configurations are compared with the conventional half-bridge (three legs) and full-bridge (five legs) topologies. These drive systems have the potential for reducing price and are suitable for applications in which the size of the system is a critical factor. Experimental and simulated results are presented.

Dual AC Drives with Five-Leg Converter

This paper present six different motor drive system topologies using shared-leg five-leg converters. All the topologies use ten power switches and does not have any connection to the mid-point of the capacitor bank. The pulse-width modulation techniques and the control strategies are investigated. The main characteristics of the drive systems are also presented. Experimental results are presented

AC Motor Drives With a Reduced Number of Switches and Boost Inductors

This paper presents eight three-phase ac motor-drive configurations that operate with a reduced number of switches and boost inductors. Four of the configurations are single-motor drives, and four of the configurations are double-motor drives. The drives provide both bidirectional power flow and power-factor control. This paper presents the analysis and control strategy of the systems, including current control and pulsewidth-modulation strategy. In spite of using a reduced number of components, the dc-link voltage and the machine currents of some of the proposed configurations are not much larger than the equivalent values of the conventional configurations. These drive systems are suitable for applications where the size of the system is a critical factor. The experimental results demonstrate the feasibility of the proposed topologies

Reducing the inductor size and current stress by interleaved bidirectional boost rectifiers used for power factor correction

Bidirectional boost rectifiers are widely employed in high power factor correction (PFC). Besides the half-bridge boost rectifier (HBR), and bipolar voltage (BVM) and unipolar voltage (UVM) modes of operation with the full-bridge boost rectifier (FBR), this paper investigates the case in which one leg of the FBR operates at the line frequency while the other one is modulated at higher frequency (clamped unipolar voltage mode, CUVM). In addition this paper proposes two interleaved boost rectifiers, one in a HBR version and the other in a FBR version. These topologies alleviate the current stress and inductor size problems present in the both HBR and FBR. Besides the theoretical analysis of the proposed topologies the paper presents a quantitative study of the inductor size and input current ripple reduction when compared to the basic HBR and FBR topologies. The IFBR reduces of 50% the inductor size, the semiconductor current stress, and the switching losses with respect to the UVM option as applied to FBR Also, the IHBR topology reduces the inductor size to less than 25% and the semiconductor current stress to 50% when compared to the basic HBR. The two proposed topologies are suitable for high power applications. Simulated and experimental results confirm the theoretical analysis.

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.

Reduced switch count multi-motor drive systems

This paper proposes two component minimized drive configurations for supplying multiple two-phase AC motors. Configuration A uses multiple two-phase motors that share a common leg. Configuration B uses multiple two-phase motors that share the mid-point of the capacitor bank at the DC-link. The principal characteristics of the drive systems are presented together experimental results

Active power line conditioner applied to single-phase to three-phase systems

In this paper, an active power line conditioner is conceived for harmonic and reactive power compensation in the single-phase to three-phase systems. The proposed system is divided into two classes: a) parallel active power filter at the single-phase grid side; and b) series active power filter at the three-phase load side. Compared with conventional five-leg single-phase to three-phase converter, the proposed system presents some advantages, like lower dc-link voltages and lower currents of the legs. A suitable control strategy is presented to regulate the load voltages, power factor of the grid close to one, and to minimize the voltage and current harmonics simultaneously. Simulated and experimental results are also presented.

Control of the Single-Phase to Three-Phase Four-leg Converter for Constant Frequency Output Voltage

This paper proposes a control strategy to a reduced switch count single-phase to three-phase converter for constant frequency output voltage applications. The topology allows single-phase to three-phase power conversion for supply three-phase load. The control strategy is proposed to obtain the same voltage rating of a five-leg converter. The system can be used for applications in which the load operates with constant frequency. Pulse-width modulation techniques are developed, introducing the concept of local and general apportioning factor. Experimental and simulated results are presented