LCL Resonant Circuit Research Articles

Bidirectional Resonant DC-DC Converter for Microgrid applications

This paper presents a non-isolated bidirectional soft-switching dc-dc converter for DC microgrid energy storage synchronization. To assist the soft switching of switches and diodes, the LCL resonant circuit is applied and an input end half-bridge boost converter is enforced. Using the voltage doubler circuit introduced on the output side, a voltage gain of 2X is achieved. Through the non-isolated circuit, the total voltage gain is obtained. The capacitive divider halves the voltage on the greater hand. The circuit performs a high frequency ripple of low output voltage. Diodes guarantee zero voltage Turn ON for switches and zero current turn ON and turn OFF during buck / boost operation Although no internal snubber circuits are available, the circuit ensures low voltage stress across semiconductor systems.

Analysis of the resonant LCL circuit operation: the case of discontinuous current

The article is focused on the analysis of the LCL resonant circuit, which operates under discontinuous input current condition. This condition leads to the LCL topology variability phenomenon what drastically changes Inverter-LCL system properties. The LCL topology variability phenomenon is precisely described. The analytical analysis presents formulae that express VSI-LCL converter features. The theoretical results are compared with laboratory tests. The concept of Controlled Variable Frequency Resonant Converter is presented and illustrated by simulation tests. The principle of CVFRC operation is based on the LCL topology variability phenomenon.

LCL‐resonant single‐switch isolated DC–DC converter

Isolated converters are desirable in DC-DC power conversion applications where an isolation and/or a large voltage step-up gain is needed. The existing isolated DC-DC converters either utilise many switches to achieve high efficiency or use few switches which result in low efficiency. This study proposes a new single switch, isolated DC-DC converter with an LCL-resonant circuit. The proposed isolated DC-DC converter has the advantages of not only using the least number of switches (i.e. one switch), but also achieving zero-current switching when the switch is turned off. Experimental results are provided to validate the theoretical analysis of the proposed converter. Results show that the proposed converter has lower voltage stress and higher efficiency than the corresponding hard-switched converter.

A Non-Isolated Bidirectional Soft Switching Current fed LCL Resonant DC/DC Converter to Interface Energy Storage in DC Microgrid

This paper proposes a current-fed non-isolated soft-switching bidirectional dc/dc converter for interfacing energy storage to dc microgrid. The proposed converter employs a current-fed half-bridge boost converter at front-end followed by an LCL resonant circuit to aid in soft-switching of semiconductor devices. A voltage doubler at output is selected to enhance the gain by $2 \times $ . The LCL resonant circuit also adds a suitable voltage gain. Therefore, the topology offers overall high voltage gain without transformer or large number of multiplier circuits. For buck operation, high side voltage is first divided by half with capacitor divider to gain higher stepdown ratio. Converter operates at high switching frequency to realize merits of reduced magnetics and filters. Zero voltage turn-on is achieved for all switches and zero current turn-on and turn-off is achieved for all diodes for both buck/boost operation. Voltage across switches and diode is clamped naturally without any external snubber circuit. Detailed analysis and design have been proposed. A proof-of-concept experimental prototype rated at 350 W has been designed, developed, and tested in the laboratory to demonstrate the performance and validate the claims of the converter for wide load variation.

Rezonansowy układ LCL w zastosowaniach przemysłowych

The paper presents chosen applications of LCL resonant circuit. Its induction heating application results in easy modular system designing and allows creating the resonant converter with variable frequency. Application of ultrasonic power systems allows efficient filtration of higher harmonics of the inverter output voltage waveform and the construction of resonant converters for virtually constant frequency equal to the frequency of mechanical resonance piezoceramic transducer. The VSI-LCL IH system operation principles and the basic analytical analysis are described. The experimental and simulations test have been made. The research results are shown. (LCL Resonant Circuit Industrial Applications).