Non‐isolated high step‐up three‐port converter with single magnetic element for photovoltaic systems

Abstract

A new non-isolated high-voltage gain three-port converter for standalone photovoltaic systems is proposed. The magnetic element of this converter is only one coupled inductor. The primary winding of the coupled inductor is shared between battery charger circuit and main converter. Leakage inductance energy of the coupled inductor is either transferred to battery or is regenerated via the passive-clamp circuit. Using switched capacitor and voltage lift techniques, the voltage gain is significantly increased for both low-voltage ports. Single magnetic element, high-voltage gain with reasonable duty cycle, lowvoltage stress on the switches, low winding turn ratio of coupled inductor and high efficiency are the merits of this converter. The operation principles and the steady-state analysis are described for the three modes of: single-input single-output, single-input dual-output and dual-input single-output. To verify the theoretical analysis, a laboratory prototype with 28 V input, 48 V battery voltage and 380 V output voltage is implemented and tested.

Non‐isolated high step‐up dual‐input DC‐DC converter with zero‐voltage transition

“…Also, coupled inductors are used to increase the voltage gain in Faraji et al Moreover, fully soft switching conditions are provided but input currents are pulsating. Honarjoo et al and Varesi et al have higher voltage gain and lower voltage stress of switches than the proposed converter. However, Honarjoo et al suffers from pulsating input currents with a high number of capacitors and the switches turn off under hard switching conditions.…”

“…Honarjoo et al and Varesi et al have higher voltage gain and lower voltage stress of switches than the proposed converter. However, Honarjoo et al suffers from pulsating input currents with a high number of capacitors and the switches turn off under hard switching conditions. The efficiency of Varesi et al is lower than the proposed converter due to the hard switching conditions.…”

“…1 Accordingly, a high step-up converter is needed to increase the low voltage of the PV panels to a suitable DC bus voltage of inverters or other applications. 2 Cascaded converter, 3,4 coupled inductor, 5,6 switched capacitor, 7,8 diode-capacitor multiplier, [9][10][11] or their combination 12,13 can be mentioned for high step-up methods. By applying these techniques, the drawback of extreme duty cycles in conventional converters is solved for high step-up conversion.…”

“…In Tofoli et al and Forouzesh et al, various high step‐up techniques are comprehensively surveyed and classified. For instance, the coupled inductor can be used to achieve a high step‐up conversion ratio but the leakage inductance leads to increased switch voltage stress. Also, high step‐up converters based on coupled inductor are not suitable for grid‐connected PV power generation system due to pulsating input current .…”

Modeling and Control of a Multiport Converter based EV Charging Station with PV and Battery

“…Considering the high power density and high efficiency merits of the multiport power converters [6], a multiport DC/DC converter is employed in this paper for the EV charging station instead of using three separate DC/DC converters. Among the aforementioned research, the charging station architectures can be classified into two topologies: using AC bus or DC bus [7]. As PV output and BES can both be regarded as DC current source [8], DC bus charging station is chosen here to improve the utilization efficiency of solar energy and decrease the cost and losses of converters.…”