scholarly journals On the Practical Evaluation of the Switching Loss in the Secondary Side Rectifiers of LLC Converters

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5915
Author(s):  
Manuel Escudero ◽  
Matteo-Alessandro Kutschak ◽  
Francesco Pulsinelli ◽  
Noel Rodriguez ◽  
Diego Pedro Morales
Keyword(s):  
Resonant Frequency ◽  
High Voltage ◽  
Low Voltage ◽  
Hysteresis Loss ◽  
Resonant Converters ◽  
Switching Loss ◽  
Operating Modes ◽  
Switching Losses ◽  
Series Resonant ◽  
Secondary Side

The switching loss of the secondary side rectifiers in LLC resonant converters can have a noticeable impact on the overall efficiency of the complete power supply and constrain the upper limit of the optimum switching frequencies of the converter. Two are the main contributions to the switching loss in the secondary side rectifiers: on the one hand, the reverse recovery loss (Qrr), most noticeably while operating above the series resonant frequency; and on the other hand, the output capacitance (Coss) hysteresis loss, not previously reported elsewhere, but present in all the operating modes of the converter (under and above the series resonant frequency). In this paper, a new technique is proposed for the measurement of the switching losses in the rectifiers of the LLC and other isolated converters. Moreover, two new circuits are introduced for the isolation and measurement of the Coss hysteresis loss, which can be applied to both high-voltage and low-voltage semiconductor devices. Finally, the analysis is experimentally demonstrated, characterizing the switching loss of the rectifiers in a 3 kW LLC converter (410 V input to 50 V output). Furthermore, the Coss hysteresis loss of several high-voltage and low-voltage devices is experimentally verified in the newly proposed measurement circuits.

scholarly journals Resonant Converter with Soft Switching and Wide Voltage Operation

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3479 ◽  
Author(s):  
Bor-Ren Lin
Keyword(s):  
Output Voltage ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Resonant Converters ◽  
Resonant Converter ◽  
Switching Loss ◽  
Voltage Range ◽  
Power Diodes ◽  
Switching Losses ◽  
In Series

A new DC/DC resonant converter with wide output voltage range operation is presented and studied to have the benefits of low switching losses on active devices and low voltage stresses on power diodes. To overcome serious reverse recovery losses of power diodes on a conventional full-bridge pulse-width modulation converter, the resonant converter is adopted to reduce the switching loss and increase the circuit efficiency. To extend the output voltage range in conventional half-bridge or full-bridge resonant converters, the secondary sides of two diode rectifiers are connected in series to have wide output voltage operation. The proposed converter can be either operated at one-resonant-converter mode for low voltage range or two-resonant-converter mode for high voltage range. Thus, the voltage rating of power diodes is decreased. Experiments with the design example are given to show the circuit performance and validate the theoretical discussion and analysis.

scholarly journals Optimal Design of Multi-Output LLC Resonant Converter with Independently Regulated Synchronous Single-Switched Power-Regulator

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4341
Author(s):  
Sang Gab Park ◽  
Byoung Kuk Lee ◽  
Jong Soo Kim
Keyword(s):  
Electromagnetic Interference ◽  
Resonant Converter ◽  
Switching Losses ◽  
Zero Current Switching ◽  
Zero Current ◽  
Series Resonant ◽  
Power Switches ◽  
Voltage Doubler ◽  
Llc Resonant Converter ◽  
Secondary Side

This paper presents a tightly regulated multi-output isolated converter that employs only an independently regulated synchronous Single-Switched Post-Regulator (SSPR). The proposed converter is a highly accurate single-ended secondary side post-regulator based on a Series Resonant Converter (SRC); furthermore, it has a voltage-doubler characteristic. The proposed post-regulator requires only one auxiliary switch, in contrast with a bulky and expensive non-isolated DC–DC converter. Moreover, the added voltage-doubler can tightly regulate the slave output current. In addition, the voltage-doubler can improve electromagnetic interference characteristics and reduce switching losses arising from the Zero Current Switching (ZCS) operation of all power switches. The validity of the proposed converter is verified using experimental results obtained via a prototype converter applicable to an LED 3D TV power supply.

scholarly journals Modified Modulation Strategy of 1: 1: 2 Asymmetric Nine-Level Inverter and Its Power Balance Method

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 75
Author(s):  
Manyuan Ye ◽  
Qiwen Wei ◽  
Wei Ren ◽  
Guizhi Song
Keyword(s):  
Output Power ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Low Voltage ◽  
Balance Control ◽  
Power Balance ◽  
Switching Loss ◽  
Switching Losses ◽  
Hybrid Frequency

The three unit nine-level inverter can output more voltage levels with fewer h-bridge units, while having better output waveform quality. However, in the conventional hybrid frequency modulation strategy, only one low-voltage unit adopts pulse width modulation (PWM), which causes the problem of switching loss and uneven heat distribution between the two low-voltage units. At the same time, the output power of the conventional modulation strategy is unbalanced. Aiming to resolve the above problems, a modified hybrid modulation strategy and a power balance control method under the strategy is proposed in this paper. The modulation strategy achieves output power balance between the three units and an even distribution of switching losses between the two low voltage units while maintaining the same output power quality. Simulation and experimental results verify the feasibility of the modulation strategy.

An Embedded Half-Bridge Γ-Z-Source Inverter with Reduced Voltage Stress on Capacitors

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6433
Author(s):  
Hamed Mashinchi Maheri ◽  
Dmitri Vinnikov ◽  
Mohsen Hasan Babayi Nozadian ◽  
Elias Shokati Asl ◽  
Ebrahim Babaei ◽  
...  
Keyword(s):  
High Voltage ◽  
Power Loss ◽  
Low Voltage ◽  
Voltage Gain ◽  
Correct Operation ◽  
Operating Modes ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
Boost Factor ◽  
Zero Voltage

In this paper, an embedded half-bridge Z-source inverter based on gamma structure is proposed. In contrast with the classical half-bridge inverter, the proposed inverter can generate zero voltage levels in output. High voltage gain and low voltage stress on capacitors are the main advantages of the proposed converter. The value of the boost factor in the proposed structure is increased by changing both the shoot-through (ST) duty cycle and turns ratio of the transformer. The operating principle of the proposed converter in four operating modes is presented. We also calculate the critical inductance and compare the proposed converter with conventional topologies. In addition, power loss and THD analysis are presented. Finally, PSCAD/EMTDC software is used to verify the correct operation of the proposed inverter and the experimental results.

scholarly journals A Soft-Switched DC/DC Converter Using Integrated Dual Half-Bridge with High Voltage Gain and Low Voltage Stress for DC Microgrid Applications

Inventions ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Hadi Moradisizkoohi ◽  
Nour Elsayad ◽  
Osama Mohammed
Keyword(s):  
High Voltage ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Voltage Gain ◽  
Switching Loss ◽  
Output Stage ◽  
Dc Microgrid ◽  
Analysis And Design ◽  
High Voltage Gain ◽  
Voltage Stress

In this paper, a soft-switched boost converter including an integrated dual half-bridge circuit with high voltage gain and continuous input current is introduced that can be suitable for the applications requiring a wide voltage gain range, such as for the front-end of the inverter in a DC microgrid to integrate renewable energy sources (RES). In the proposed converter, two half-bridge converters are connected in series at the output stage to enhance the voltage gain. Additionally, the balanced voltage multiplier stage is employed at the output to increase the voltage conversion ratio, as well as distribute the voltage stress across semiconductors; hence, switches with smaller on-resistance RDS(on) can be adopted resulting in an improvement in the efficiency. The converter takes advantage of the clamp circuit not only to confine the voltage stress of switches, but also to achieve the soft-switching, which leads to a reduction in the switching loss as well as the cost. The mentioned features make the proposed converter a proper choice for interfacing RES to the DC-link bus of the inverter. The operation modes, steady-state analysis, and design consideration of the proposed topology have been demonstrated in the paper. A 1-kW laboratory prototype was built using gallium nitride (GaN) transistors and silicon carbide (SiC) diodes to confirm the effectiveness of the proposed topology.

scholarly journals Design and Implementation of Improved High Step-Down DC-DC Converter for Electric Vehicles

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4206
Author(s):  
Dong-Ryeol Park ◽  
Yong Kim
Keyword(s):  
Electric Vehicles ◽  
High Efficiency ◽  
Low Voltage ◽  
Switching Frequency ◽  
Switching Loss ◽  
High Switching Frequency ◽  
Voltage Stress ◽  
Power Switches ◽  
Step Down ◽  
Secondary Side

An improved high step-down DC-DC converter for charging the batteries in an electric vehicle application is proposed in this paper. It adopts the topology of the conventional full-bridge converter, which has a coupled inductor current-doubler rectifier as the secondary side of the transformer. In addition, four power switches are driven using a phase-shifting technique. The proposed converter can achieve a high step-down voltage with low-voltage stress on the rectifier diodes. In addition, the coupled inductor current-doubler rectifier of the secondary side can reduce the ripple current and losses of the secondary side to achieve high efficiency. Furthermore, the proposed converter can overcome the drawbacks of the conventional full-bridge converter, such as switching loss caused by high switching frequency, duty-cycle loss, voltage stress, and numerous components, and can increase the efficiency with the soft-switching technique. A 600 W laboratory prototype of the proposed converter was manufactured. The results of the experiments performed with the prototype proved the effectiveness and validated the use of the proposed converter for better charging of electric vehicles.

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