Interleaved Boost-Integrated <italic>LLC</italic> Resonant Converter With Fixed-Frequency PWM Control for Renewable Energy Generation Applications

Abstract

This paper proposes a current-fed LLC resonant converter that is able to achieve high efficiency over a wide input voltage range. It is derived by integrating a two-phase interleaved Boost circuit and a full-bridge LLC circuit together by virtue of sharing the same full-bridge switching unit. Compared with conventional full-bridge LLC converter, the gain characteristic is improved in terms of both gain range and optimal operation area, fixed-frequency PWM control is employed to achieve output voltage regulation, and the input current ripple is minimized as well. The voltage across the turned-off primary-side switch can be always clamped by the bus voltage, reducing the switch voltage stress. Besides, its other distinct features, such as single-stage configuration, and soft switching for all switches also contribute to high power conversion efficiency. The operation principles are presented, and then the main characteristics regarding gain, input current ripple, and zero voltage switching (ZVS) considering the nonlinear output capacitance of MOSFET, are investigated and compared with conventional solutions. Also, the design procedure for some key parameters is presented, and two kinds of interleaved Boost integrated resonant converter topologies are generalized. Finally, experimental results of a converter prototype with 120-240V input and 24V/25A output verify all considerations.Index Terms-Current-fed converter, LLC resonant converter, fixed-frequency PWM control, wide voltage gain range. 0885-8993 (c)

Pulse Width and Frequency Hybrid Modulated LLC Converter Adapted to Ultra Wide Voltage Range

“…This DC-DC resonant converter topology has been derived from the full-bridge LLC topology with voltage doubler structure at the secondary side of the transformer. In comparison with the orthodox voltage doubler configuration, Numerous techniques to narrow down the LLC converter operation frequency have been proposed in the literature [8,[15][16][17][18]. In [8], the designed LLC converter is incorporated with a two-phase interleaved boost circuit.…”

“…LLC resonant topology has a simple structure and reduced EMI. Moreover, switching losses can be decreased by extending the zero voltage switching (ZVS) and zero current switching (ZCS) range of MOSFETs and power diodes respectively [7][8][9]. Hence, LLC is regarded as the more suitable structure opted for EVs chargers [10][11][12].…”

Highly Efficient and Reliable SiC-Based DC–DC Converter for Smart Transformer

“…The considered capacitors are: 150nF, 330nF, 680nF, all rated for 400 V ac / 650 V dc . According to [31], for this kind of capacitor, the lifetime model is given by (9), where L o is the expected lifetime tested by the manufacturer, V Cpk and V o are the capacitor voltage at use condition and test condition, respectively. T and T o are the temperature at use condition and test condition, respectively, in Kelvin.…”

Bidirectional series-resonant DC-DC converter with fault-tolerance capability for smart transformer

“…The instantaneous average value of the input current (i i ) is calculated by (9). As highlighted in this equation, the integral of the current during the time interval 0 to T s /2 is the charge accumulated in the capacitor (see Fig.…”