Interleaved non‐isolated high step‐up DC/DC converter based on the diode–capacitor multiplier

Abstract

A kind of interleaved non-isolated high step-up DC/DC converter is presented in this study. The converter consists of two basic Boost cells and some diode-capacitor multiplier (DCM) cells as needed. Because of the DCM cells, the voltage conversion ratio is enlarged and the extreme large duty ratio can be avoided in the high step-up applications. Moreover, the voltage stress of all the power devices is greatly lower than the output voltage. As a result, lower-voltage-rated power devices can be employed, and higher efficiency can be expected. Since the two basic Boost cells are controlled by the interleaving method, which means the phase difference between the two pulse width moderlation (PWM) signals is 180°and the input current is the sums of the two inductor currents, the input current ripple is decreased and the size of the input filter could be reduced, which make it a suitable choice in the photovoltaic power generation system and hybrid electric vehicles, etc. Finally, the experimental results from a 300 W, 30-400 V laboratory prototype are presented to validate the effectiveness of the proposed converter.

A Wide Input-Voltage Range Quasi-Z-Source Boost DC–DC Converter With High-Voltage Gain for Fuel Cell Vehicles

“…It is noticed that the maximum measured efficiency is 95.13% as shown in Fig. 15, which is higher than the maximum efficiencies 89.3%, 94.37%, and 94% claimed in [29]- [31], respectively. In addition, when the output power is constant and the input voltage declines, the efficiency decreases correspondingly, due to the increasing losses caused by the increasing input current.…”

“…4. Moreover, in the higher duty cycle range, the voltage-gain of the converter in [31] is lower than that of the proposed one. Especially, the ripple reduction of the input current will be affected both in the lower and higher duty cycle ranges, which are not close to 0.5.…”

“…However, its voltage-gain depends on the turns ratio N. Even worse, the potential difference between the input and output sides is appeared as the PWM voltage, due to the non-common grounds. While the interleaved step-up DC-DC converter with the diode-capacitor multiplier [31] can obtain a common ground, and its voltage-gain is the same with that of the converter in [30]. In addition, the ripple of its input current can be reduced more when the duty cycles of the two power switches are around 0.5, due to the interleaved structure with one more power switch.…”

“…According to (31) and the experimental parameters in TABLE II, when the input voltage is U in =40V, the control-to-output transfer function can be achieved from the time domain to the complex frequency as (32). (33), and H(s) is the feedback transfer function.…”

Neuro‐fuzzy controller for battery equalisation in serially connected lithium battery pack

“…Voltage monitoring, a battery equalisation scheme and equalisation control are important parts of a serially connected lithium-ion battery system. There have been many studies on equalisation circuits and control algorithms to equalise battery cell voltages using individual cell equalisers (ICEs) based on DC-DC converters [3][4][5][6]. These can be categorised into unidirectional and bidirectional non-dissipative current equalisation.…”