scholarly journals A Variable-Structure Multi-Resonant DC–DC Converter with Smooth Switching

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2240 ◽  
Author(s):  
Mengying Chen ◽  
Yifeng Wang ◽  
Liang Yang ◽  
Fuqiang Han ◽  
Yuqi Hou ◽  
...  

In this paper, a variable-structure multi-resonant soft-switching DC–DC converter and its transient smooth control method are proposed. Through the introduction of auxiliary switches, the converter can flexibly adjust its structure among three operating modes. Two switching processes can be obtained. Thus, a wide voltage gain range is achieved within a narrow frequency range. Moreover, to eliminate the large voltage fluctuation during modes switching, a drive signal gradual adjustment control method is proposed. Consequently, smooth switching between different modes can be realized and the voltage fluctuation is suppressed effectively. Finally, a 200 W experimental prototype is established to verify the theoretical analyses. Soft-switching performances for power switches and diodes are both guaranteed. The highest efficiency is 98.2%. With the proposed transient control method, a basically constant 400 V output voltage is ensured within a wide input voltage range (80 V–600 V). In particular, the transient voltage fluctuations during two switching processes decrease from 38.4 V to 10.8 V and from 37.2 V to 8.4 V, respectively.

Interleaved Boost Full Bridge integrated LLC resonant (IBFB- LLC) is an isolated DC/DC converter with directional power flow, which can cope with a wide input voltage range of PV applications. The main losses of the converter are switching losses of the power switches and transformers losses. This paper proposes a method to improve the efficiency of the IBFB converter due to zero voltage switching technique, in combination with employing new SiC MOSFET technology instead of the conventional Si MOSFET. In addition, Litz wire is also adopted to reduce the losses on the high frequency isolation transformer. Both numerical simulations and experiments with a prototype 2.5kW converter are implemented to verify the feasibility and effectiveness of the proposed solution.


2014 ◽  
Vol 23 (03) ◽  
pp. 1450038 ◽  
Author(s):  
LING-FENG SHI ◽  
HUI-LI GUAN ◽  
QIN-QIN LI ◽  
XIN-QUAN LAI

A novel control method for the critical conduction mode (CRM) power factor correction (PFC) converter is presented, which reduces the size of the boost inductor in the system with wide input-voltage range and improves the efficiency of the system with low input voltage. By introducing the following boost circuit, the output voltage in the application circuit varies with the input root mean square (RMS) voltage to reduce the demand for the large size of the inductor and the efficiency of the system keeps high under the low input voltage. A novel CRM PFC control system with smaller size inductor and higher efficiency is achieved by applied the following boost method to the core control circuits. Experiment results show that the inductance value of the boost inductor is 430 μH using the presented PFC control system and 700 μH using the traditional PFC control system when the input voltage varies from 85 V to 265 V. The novel control method decreases the inductor's value at 38.2%, and the efficiency of the system improves at 1.62% under the input voltage of 85 V.


Energies ◽  
2018 ◽  
Vol 11 (4) ◽  
pp. 717 ◽  
Author(s):  
Jintae Kim ◽  
Chung-Yuen Won

An improved modulated carrier control (MCC) method is proposed to offer high power factor (PF) and low total harmonic distortion (THD) at a wide input voltage range and load variation. The conventional MCC method not only requires a multiplier and divider, but also is hard to be implemented with a micro controller unit without a high frequency oscillator. To overcome the problem and maintain the advantages of the conventional MCC method, the proposed MCC method adopts a current integrator, an output voltage amplifier, a zero-current duration (ZCD) demodulator of the boost inductor, and a carrier generator. Thus, it can remove a multiplier and well, as it allows for being operable with a general micro control unit. This paper presents an operation principle of the proposed control method. To verify the proposed control method, experimental results with 400 W PFC boost converter is demonstrated.


Electronics ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 47 ◽  
Author(s):  
Bor-Ren Lin

A soft switching three-level pulse-width modulation (PWM) converter is presented for industrial electronics with wide voltage range operation, such as solar power or fuel cell applications. Phase shift PWM scheme is used on the input-side to accomplish the zero voltage turn-on on power switches and improve the converter efficiency. Three-level diode-clamp circuit topology is adopted in the presented circuit to lessen the voltage ratings on active devices for high voltage applications. Three sub-circuits with the different turns-ratio of transformers can be selected in the presented converter in order to achieve 10:1 (Vin,max = 10Vin,min) wide input voltage operation when compared to the conventional multilevel converter. The proposed circuit is a single-stage converter instead of two-stage converter to realize wide voltage operation. Therefore, the presented converter has less component counts. Finally, the design procedure and experiments with a 300W laboratory circuit are presented and discussed to confirm the circuit analysis and converter performance.


Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 222
Author(s):  
Bor-Ren Lin

A phase-shift pulse-width modulation converter is studied and investigated for railway vehicle or solar cell power converter applications with wide voltage operation. For railway vehicle applications, input voltage range of dc converters is requested to have 30–40% voltage variation of the nominal input voltage. The nominal input voltages of dc converters on railway vehicles applications may be 37.5 V, 48 V, 72 V, 96 V and 110 V. Therefore, a new dc converter with wide input voltage operation from 25 to 150 V is presented to withstand different nominal input voltage levels such as 37.5–110 V on railway power units. To realize wide input voltage operation, an auxiliary switch and auxiliary transformer windings are used on output side of conventional full-bridge converter to have different voltage gains under different input voltage values. Phase-shift pulse-width modulation is adopted in the developed dc converter to accomplish soft switching operation on power switches. To confirm and validate the practicability of the presented converter, experiments based on a 300 W prototype were provided in this paper.


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