A Current-Sharing Driving Method for Multilevel Current Reinjection Converter

Feng

et al. 2022

Circuit Theory & Apps

In the application of bipolar DC bus configuration in the DC nanogrid, the unbalanced voltage of two outputs in bipolar DC bus, due to the unbalanced conditions of loads and/or energy sources, will cause deterioration of the power quality of the bus and may damage the switch, affecting the stability and safety of the system. In order to solve the problem of unbalanced voltage of two outputs, interleaved series capacitor based dual‐output converter with a high conversion ratio is presented in this paper. By applying negative current mode (NCM) to the main inductor, the character of two‐output self‐balancing and zero voltage switching (ZVS) of all switches for such this topology configuration is achieved. In the NCM mode, the parallel diodes of main switches are not conducted during dead time and guarantee the flowing path to load side. Thus, based on this condition, volt‐second balance of main inductor is obtained to get the character of two‐output self‐balancing. Furthermore, by adopting series capacitor in the proposed topology and based on the charge‐balance of the intermediate block capacitor, inductor current existed in the two phase could be auto‐sharing. Comprehensive operational principle analysis, loss analysis, and efficiency of the proposed converter under different load conditions have been given, and the comparison analysis of three operation modes and selection of negative current mode is clarified. Small signal model of the proposed converter is described to convenient for the controller design. Finally, simulation results and a 20–220 V prototype are built to verify the character analysis of the proposed converter.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interleaved high conversion ratio DC–DC converter with output self‐balancing and current auto‐sharing for DC nanogrid application

Feng

et al. 2022

Circuit Theory & Apps

“…However, current sharing issues must be carefully taken into account as unbalance may be caused by small differences in the duty cycles applied to the active switches and/or intrinsic constructive differences regarding the power stage elements [11]. In this case, complex and costly control circuits and techniques may be necessary [12], especially considering that the unbalanced current may cause additional thermal stress on one phase, also leading to inadequate triggering of protection circuits [13].…”

Section: Introductionmentioning

confidence: 99%

Survey on topologies based on the three‐state and multi‐state switching cells

Tofoli¹,

Tavares²,

Saldanha³

2019

IET Power Electronics

The introduction of the three-state switching cell (3SSC) and the multi-state switching cell (MSSC) has led to the proposal of several converter topologies, where prominent characteristics regarding reduced dimensions of filter elements, high efficiency, and increase of maximum power levels are achieved. Even though the active switches associated to the 3SSC and MSSC are driven by signals obtained from multiple phase-shifted carriers similarly to the interleaving technique, there are significant differences between the aforementioned approaches. Within this context, this work intends to analyse several converter topologies employing the 3SSC and MSSC that were previously reported in the literature. An overview of important concepts regarding interleaved and 3SSC-based converters is initially presented, as potential advantages and drawbacks are discussed in detail. Besides, it is also shown how the 3SSC and MSSC can be employed in the conception of power converter topologies for distinct applications, e.g. high-voltage step-up non-isolated dc-dc converters, power factor correction rectifiers, and multilevel inverters.

“…However, current unbalance regarding the many phases must be carefully taken into account, what may be caused by small differences in the duty ratios applied to the active switches and/or parasitics with distinct ratings regarding the power stage elements . In this case, special control circuits and techniques may be necessary to achieve proper current sharing …”

Section: Introductionmentioning

confidence: 99%

“…10 In this case, special control circuits and techniques may be necessary to achieve proper current sharing. 11 Apparently, literature does not present many works focused on interleaved buck-boost converters. 12 It is worth to mention that step-up/step-down converters are essential in practical high-power applications such as automotive power trains as discussed in Pavlovský et al, 13 where current sharing must be carefully taken into account in the converter design and operation, since the unbalanced current may cause additional thermal stress on one phase, also leading to inadequate triggering of protection circuits.…”

Section: Introductionmentioning

confidence: 99%

A step‐up/step‐down direct current to direct current converter for high‐power, high‐current applications

Feretti

Souza

Gomes

et al. 2018

Circuit Theory & Apps

Summary This work proposes the conception of a nonisolated direct current (DC)‐DC buck‐boost converter employing the three‐state switching cell. Similarly to interleaving, it is possible to achieve higher power levels than that regarding the classical buck‐boost converter, but prominent advantages over the interleaved approach result, ie, the input current is continuous for duty ratios higher than 0.5; good current sharing is achieved without the need of special control schemes; and the active switches are connected to the same reference node as the input voltage source, as there is no need to use isolated drive circuitry. A thorough quantitative and qualitative analysis is carried for the entire range of the duty cycle D, considering that the proposed converter presents distinct behaviors for D < 0.5 and D > 0.5. An experimental prototype is developed and evaluated, while the results are discussed in detail.