An Overview of Non-Isolated Hybrid Switched-Capacitor Step-Up DC–DC Converters

Abstract

The increasing interest in renewable energy sources has brought attention to large voltage-gain dc–dc converters; among the different available solutions to perform a large voltage-gain conversion, this article presents an overview of non-isolated dc–dc converter topologies that utilize switched-capacitor circuits, i.e., diode-capacitors voltage multipliers. The review includes combinations of a traditional power stage with a diode-capacitor-based voltage multiplier, such as the multilevel boost converter. This article starts by reviewing switched-capacitor (SC) circuits, different topologies, and different types of charge exchange; it provides a straightforward analysis to understand the discharging losses. It then covers the multilevel boost converter and other topologies recently introduced to the state-of-the-art. Special attention is put on SC circuits with resonant charge interchange that have recently been probed to achieve very good efficiency. An additional contribution of the article is new proof of the discharging losses in resonant switched-capacitor circuits focused on the initial and final stored energy in capacitors, and this proof explains the relatively large efficiency obtained with SC resonant converters.

A Multilevel Boost Converter with Reduced Inductor Current

“…This can be solved by adding a relatively small resonant inductor. For medium or high-power converters, the inductance associated with the wire path is enough, as previously reported for other switched capacitor circuits [10,15].…”

“…This topology is referred to in what follows as the Reduced Inductor Current Multilevel Boost Converter (RIC-MBC) and was initially introduced in [11] with preliminary results. The proposed RIC-MBC topology is similar (but not equal) to the Multilevel Boost Converter (MBC), which has been the subject of several studies leading to new families of topologies that can be sorted into converters with only one inductor [12][13][14][15][16] and interleaved or converters with more than one inductor [17][18][19][20]. Some converter families have been proposed based on the MBC principle [21]; their mathematical modeling has also been investigated [22,23].…”

“…This term explicitly appears in (15); that is, C 2 is calculated to have a particular voltage ripple while providing this charge. Now, when the switch is closed (see Figure 4a), the capacitor C 1 transfers this charge to C 2 , and both (C 1 and C 2 ) provide the load current during the on-time DT S .…”

A Critical Analysis of Quadratic Boost Based High-Gain Converters for Electric Vehicle Applications: A Review

“…The complexity of QBC is further compounded by the necessity for accurate output voltage management, electromagnetic interference problems, and efficiency challenges at light load situations. Additional challenges include dealing with transient responses, dealing with non-ideals, guaranteeing safety under different settings, and balancing the economic implications [50][51][52][53][54][55][56]. To overcome these obstacles and maximize the performance of HG-QBC, one must carefully choose components, manage heat, follow safety protocols, and employ exacting design methodologies.…”

A single‐source nine‐level boost inverter with new optimal switching scheme for EV applications

“…In such topologies, transformers are employed to increase the voltage, consequently increasing the system size. 6,12 Later, switched-capacitor (SC)-based MLI configurations 13 have emerged as an alternative solution for increasing the voltage levels and boosting output voltage without using inductors. Additionally, SCs can balance capacitor voltages without needing a complicated algorithm or additional circuitry.…”