Search

DC microgrid is gaining attraction and a recent trend in distribution power generation system due to penetration of renewables (especially photovoltaic or fuel cell). In this paper, a new triple-switch-triple-mode high step-up converter (TSTM-HS converter) is presented for dc microgrid applications. In the proposed converter, voltage lift technique is employed and range of duty cycle is extended by incorporating an additional switch in converter circuitry. By doing this, high voltage conversion ratio is achieved without using a transformer, coupled inductor, and multiple stages of switched capacitors. Moreover, the TSTM-HS converter operated in three modes with two types of the duty cycles to achieve low to high voltage conversion without using high duty cycle for each switch. The effects of difference in the inductance values on the regulation and operating behavior of the TSTM-HS converter are discussed. The continuous conduction mode and discontinuous conduction mode characteristics of the TSTM-HS converter are discussed in detail with steady-state analysis and boundary condition. The comparison is provided to highlight the benefits of the TSTM-HS converter. The selection of semiconductor devices and the design of reactive components are discussed for the TSTM-HS converter. The experimental results of the proposed converter are provided which validate the theoretical approach, performance, and feasibility of converter. [ABSTRACT FROM AUTHOR]

Conventional finite control set (FCS) predictive load-voltage control for four-leg inverters features simplification in digital implementation compared to its complex counterpart, three-dimensional space vector modulation. However, the FCS approach is typically characterized by a variable switching frequency, low steady-state performance, and a higher average switching frequency in the neutral leg than the other three legs. To overcome these shortcomings, an online duty-cycle-optimization based model predictive control technique is proposed in this article. The performance of the inverter is evaluated experimentally in terms of load voltage tracking in different operating conditions such as nonlinear loads and balanced/unbalanced references. The proposed technique fulfills the requirement of a high-performance converter, constant switching frequency, and enhanced load voltage tracking at a lower sampling rate and, thus, solves the drawbacks of the conventional FCS model predictive control for a four-leg inverter. Furthermore, the proposed approach can facilitate the overmodulation operation, which is desirable for this type of power converters under nonlinear and unbalanced loading conditions. [ABSTRACT FROM AUTHOR]

A step-up interleaved dc–dc converter (IDC) operated in three different duty regions ($0 \leq D < 0.5$ , $0.5 \leq D < 1,$ and $0 \leq D < 1$) at a reduced number of elements is presented in this article. The IDC is capable of giving different voltage-gain characteristics in the three regions. The elements of IDC have different voltage and current stresses because of the three duty regions, which leads to cost-effective device selection according to the voltage-gain requirement of a particular application. Detailed mathematical modeling of the IDC is carried out in the three regions. Moreover, a comparison is made among the reported converters and IDC in terms of component count, voltage-gain, component voltage stresses, nature of input current and output voltages, and a discussion is carried out on their pros and cons. A laboratory prototype is developed to validate the performance of IDC in the three duty regions. Also, power loss and efficiency analysis of the IDC is carried out to show its effectiveness. [ABSTRACT FROM AUTHOR]