Search

Direct current voltages unbalance of respective power cells is an inherent and critical problem in a cascaded multilevel converter, which is widely used in the solid-state transformer. In this paper, an n -dimension space vector pulse width modulation is presented to address this issue in a three-level H-bridge-based cascaded multilevel converter. This algorithm utilizes the redundant switching pairs of the inner cell and the redundant vectors of mutual cells to balance capacitors’ and cells’ voltages. Meanwhile, a smooth vector transition strategy is included in this algorithm to avoid the level-skip phenomenon. The calculation processes are analyzed in one-cell, two-cells, and three-cells modes, respectively. It is simple, calculable, and flexible to extend in n-cells mode. Finally, the voltage balancing capacity of the inner cell and mutual cells with smooth level transition are verified by simulations and experiments not only at startup but also with unbalanced loads. [ABSTRACT FROM PUBLISHER]

A nonisolated single-stage electronic lighting system with a high power factor for driving power light-emitting diodes (LEDs) is proposed in this paper. The presented topology is based on the integration of a bridgeless boost rectifier with a nonresonant half-bridge converter. Accurate steady-state analyses of the nonresonant- and resonant-based circuits are reported, serving as the basis for designing the lighting systems. The LEDs current is adjusted by means of frequency modulation, being the converter switches driven by complementary symmetrical signals. A small-signal analysis is detailed for the proposed nonresonant scheme, providing fundamental information regarding its dynamic behavior. Also, a step-by-step design procedure based on the performed mathematical analysis is elaborated, allowing the adequate design of the proposed lighting system. In order to confirm the validity and the feasibility of the proposed converter, experimental results for a 42-W, 127- \rmV{\rm{rms}}, 50-kHz, 94.2% peak efficiency prototype are presented. [ABSTRACT FROM PUBLISHER]

In this paper, a new cascaded high step-up multilevel converter topology is designed, which is based on the series connection of several switched-capacitor submultilevel units. The voltage gain of proposed multilevel converter is related to the number of used switches-capacitor units. The main advantage of proposed topology is inherent voltage balancing of used capacitors. The proposed cascade topology is optimized to minimize the number of capacitors, power switches, and the value of voltage on switches for given levels. The proposed topology is compared with other high step-up multilevel converter topologies and conventional structures. The comparison results show that the presented structure requires the least number of switches and dc sources. Moreover, the voltage on the switches of proposed topology is low. In order to confirm the operation of proposed high step-up multilevel converter, both experimental and simulation works are provided. [ABSTRACT FROM PUBLISHER]

A hybrid switched-capacitor/interleaved boost converter able to provide a high voltage gain and to cancel the input current ripple at a preselected duty cycle was recently presented in the literature. This paper extends that work by proposing an optimized switching strategy for operating conditions at other values of duty cycle. The switching strategy effect on the converter's voltage gain and input current ripple is quantified and compared against the performance under the conventional switching strategy. The approach is validated in the laboratory through hardware prototyping. [ABSTRACT FROM PUBLISHER]

This paper analyzes the interleaved boost with coupled inductors (IBCI) converter, which is an isolated topology that is suitable for high step-up applications. Two main contributions are given: an exhaustive steady-state analysis and an accurate small-signal model. The former allows for deriving a closed-form noniterative design procedure for the power-stage active and passive components. In addition, it reveals an interesting equivalence with an apparently different converter, i.e., the single active bridge. Subsequently, the IBCI converter dynamic behavior is investigated, deriving a nonlinear average model that, under small-signal approximation, can be linearized around a given operating point and used for feedback controller design. A single photovoltaic module interface converter, rated for 300-W output power, is considered as a case study to validate the analysis outcome and the design procedure. Both are fully validated by measurements taken on the laboratory prototype. [ABSTRACT FROM PUBLISHER]

Automotive embedded electronic systems have been increasing in power and complexity and, therefore, more advanced power electronic converters are necessary in these vehicles. Several dual-voltage (42 V/14 V) bidirectional converter architectures have been proposed for automotive systems in recent years. However, most of them have low efficiency or are based in series and parallel configurations with large number of semiconductors and magnetics devices. Therefore, in this paper, we propose a bidirectional high-efficiency converter with lower number of components. This converter was created by merging a switched-capacitor converter and a conventional bidirectional converter, resulting in a hybrid topology. The voltage across the semiconductors of the proposed converter is equal to half of the highest voltage source value. Furthermore, the topology is composed of only one inductor to control the power flow between the two voltage sources. To verify all the mentioned features, a prototype was implemented experimentally, reaching a maximum efficiency of 97.5%. [ABSTRACT FROM PUBLISHER]

A method for extending the duty cycle range of series-input interleaved forward converter (SII-FC) is proposed in this paper. A family of novel SII-FC topologies is derived by integrating two switching legs, which belong to two forward cells, into one switching leg shared by both the two forward cells in the SII-FC. By employing the proposed method, the derived topologies have the advantages of extended duty cycle, reduced components, and conduction losses, which help to achieve high power density and high efficiency. These advantages make the SII-FC topologies suitable for such applications with wide input voltage range. A series-input interleaved two-switch forward converter (SII-TS-FC) is analyzed in detail, which is a typical SII-FC topology developed by the proposed method. It is composed of two low-voltage switching legs and a high-voltage switching leg. Detailed analysis indicates that the maximum duty cycle of the SII-TS-FC can reach 2/3, which is 1.33 times of that of the two-switch forward converter. The switches of the high-voltage leg can be soft-switched when duty cycle is less than 0.5, while the switches of the low-voltage legs can be soft-switched when duty cycle is larger than 0.5. As a result, high efficiency is achieved over a wide voltage range. In addition, the output filter can be reduced due to the interleaving operation of the two forward cells. The operational principles, characteristics, and design considerations for the proposed SII-FC are presented. Experimental results on the SII-TS-FC prototype with 200–400 V input 48 V/12 A output verify the proposed method and analysis. [ABSTRACT FROM PUBLISHER]

This paper presents the hybrid seven-level cascaded active neutral-point-clamped (ANPC)-based multilevel converter. The converter topology is the cascaded connection of a three-level ANPC converter and an H-bridge per phase. The voltage of the H-bridge is actively maintained to the required level through selection of the switching states of the converter. The topology is operated under selective harmonic elimination pulsewidth modulation (SHE-PWM), maintaining the switching frequency of the converter to a minimum. The operating principles, voltage balancing methods, and limitations of the converter are analyzed together with extensive simulation results of the topology. Experimental results from a low-power laboratory prototype are presented that verify the operation of the hybrid converter under SHE-PWM. [ABSTRACT FROM PUBLISHER]