Optimal Soft-Switching Scheme for Bidirectional DC-DC Converters with Auxiliary Circuit

Han Rim Lee,Jin-Hyuk Park,Kyo-Beum Lee 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

This paper proposes a soft-switching bidirectional dc-dc converter (BDC) with an auxiliary circuit. The proposed BDC can achieve the zero-voltage switching (ZVS) using an auxiliary circuit in the buck and boost operations. The auxiliary circuit supplies optimal energy for the ZVS operation of the main switches. The auxiliary circuit consists of a resonant inductor, a back-to-back switch and two capacitors. A small-sized resonant inductor and an auxiliary switch with a low-rated voltage can be used in the auxiliary circuit. Zero-current switching (ZCS) turn-on and turn-off of the auxiliary switches are possible. The proposed soft-switching scheme has a look-up table for optimal switching of the auxiliary switches. The proposed strategy properly adjusts the turn-on time of the auxiliary switch according to the load current. The proposed BDC is verified by the results of PSIM simulations and experiments on a 3-kW ZVS BDC system.

Optimal Soft-Switching Scheme for Bidirectional DC-DC Converters with Auxiliary Circuit

Lee, Han Rim,Park, Jin-Hyuk,Lee, Kyo-Beum The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

This paper proposes a soft-switching bidirectional dc-dc converter (BDC) with an auxiliary circuit. The proposed BDC can achieve the zero-voltage switching (ZVS) using an auxiliary circuit in the buck and boost operations. The auxiliary circuit supplies optimal energy for the ZVS operation of the main switches. The auxiliary circuit consists of a resonant inductor, a back-to-back switch and two capacitors. A small-sized resonant inductor and an auxiliary switch with a low-rated voltage can be used in the auxiliary circuit. Zero-current switching (ZCS) turn-on and turn-off of the auxiliary switches are possible. The proposed soft-switching scheme has a look-up table for optimal switching of the auxiliary switches. The proposed strategy properly adjusts the turn-on time of the auxiliary switch according to the load current. The proposed BDC is verified by the results of PSIM simulations and experiments on a 3-kW ZVS BDC system.

클램핑 다이오드를 갖는 ARCP 인버터의 성능 분석

이윤석(Yoon-Seok Lee),김재혁(Jae-Hyuk Kim),한병문(Byung-Moon Han) 대한전기학회 2018 전기학회논문지 Vol.67 No.12

This paper proposes a new auxiliary resonant commutated pole (ARCP) inverter which has a modified auxiliary circuit. The proposed auxiliary circuit includes two auxiliary IGBT switches, an LC resonant circuit, and two clamping diodes. In order to analyze the performance of proposed ARCP inverter, computer simulations with PSCAD, and hardware experiments were carried out. Through analyzing the experimental results, it is known that the proposed ARCP inverter offers efficiency improvement of 1.5% compared with the hard-switching inverter.

PFC ZVT-PWM 승압형 컨버터에서 통합형 멀티칩 전력 모듈 제조를 위한 개선된 소프트 스위치 보조 공진 회로

김용욱(Yong-Wook Kim),김래영(Rae-Young Kim),소재환(Jae-Hwan Soh),최기영(Ki-Young Choi) 전력전자학회 2013 전력전자학회 논문지 Vol.18 No.5

This paper proposes a novel soft-switched auxiliary resonant circuit to provide a Zero-Voltage-Transition at turn-on for a conventional PWM boost converter in a PFC application. The proposed auxiliary circuit enables a main switch of the boost converter to turn on under a zero voltage switching condition and simultaneously achieves both soft-switched turn-on and turn?off. Moreover, for the purpose of an intelligent multi-chip power module fabrication, the proposed circuit is designed to satisfy several design constraints including space saving, low cost, and easy fabrication. As a result, the circuit is easily realized by a low rated MOSFET and a small inductor. Detail operation and the circuit waveform are theoretically explained and then simulation and experimental results are provided based on a 1.8 kW prototype PFC converter in order to verify the effectiveness of the proposed circuit.

Fault Tolerant Operation of CHB Multilevel Inverters Based on the SVM Technique Using an Auxiliary Unit

Kumar, B. Hemanth,Lokhande, Makarand M.,Karasani, Raghavendra Reddy,Borghate, Vijay B. The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

In this paper, an improved Space Vector Modulation (SVM) based fault tolerant operation on a nine-level Cascaded H-Bridge (CHB) inverter with an additional backup circuit is proposed. Any type of fault in a power converter may result in a power interruption and productivity loss. Three different faults on H-bridge modules in all three phases based on the SVM approach are investigated with diagrams. Any fault in an inverter phase creates an unbalanced output voltage, which can lead to instability in the system. An additional auxiliary unit is connected in series to the three phase cascaded H-bridge circuit. With the help of this and the redundant switching states in SVM, the CHB inverter produces a balanced output with low harmonic distortion. This ensures high DC bus utilization under numerous fault conditions in three phases, which improves the system reliability. Simulation results are presented on three phase nine-level inverter with the automatic fault detection algorithm in the MATLAB/SIMULINK software tool, and experimental results are presented with DSP on five-level inverter to validate the practicality of the proposed SVM fault tolerance strategy on a CHB inverter with an auxiliary circuit.

Fault Tolerant Operation of CHB Multilevel Inverters Based on the SVM Technique Using an Auxiliary Unit

B. Hemanth Kumar,Makarand M. Lokhande,Raghavendra Reddy Karasani,Vijay B. Borghate 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

In this paper, an improved Space Vector Modulation (SVM) based fault tolerant operation on a nine-level Cascaded H-Bridge (CHB) inverter with an additional backup circuit is proposed. Any type of fault in a power converter may result in a power interruption and productivity loss. Three different faults on H-bridge modules in all three phases based on the SVM approach are investigated with diagrams. Any fault in an inverter phase creates an unbalanced output voltage, which can lead to instability in the system. An additional auxiliary unit is connected in series to the three phase cascaded H-bridge circuit. With the help of this and the redundant switching states in SVM, the CHB inverter produces a balanced output with low harmonic distortion. This ensures high DC bus utilization under numerous fault conditions in three phases, which improves the system reliability. Simulation results are presented on three phase nine-level inverter with the automatic fault detection algorithm in the MATLAB/SIMULINK software tool, and experimental results are presented with DSP on five-level inverter to validate the practicality of the proposed SVM fault tolerance strategy on a CHB inverter with an auxiliary circuit.

1차측 보조회로를 이용한 Three-Level 컨버터에 관한 연구

裵辰容(Jin-Yong Bae),金龍(Yong Kim),曺圭滿(Kyu-Man Cho) 대한전기학회 2008 전기학회논문지 Vol.57 No.6

A New ZVS(Zero Voltage Switching) and ZVZCS(Zero Voltage and Zero Current Switching) Three-Level Converter is proposed. The proposed converter presented in this paper used a phase shift control with a flying capacitor in the primary side to achieve ZVS for the all switch. A primary auxiliary circuit, which consists of one coupled inductor, is added in the primary to provide ZVZCS conditions to primary switches. Many advantages including simple circuit topology high efficiency, and low cost make this converter attractive for high power applications. The principle of operation, feature and design considerations are illustrated and verified through the experiment with a 2㎾ (27V, 74A) 40 ㎑ IGBT based experimental circuit.

ZCS 인버터에 의해 구동되는 3상 유도전동기 시스템의 효율향상에 관한 연구

배진용,김용,백수현,이은영,김필수,최근수,Bae, Jin-Yong,Kim, Yong,Baek, Soo-Hyun,Lee, Eun-Young,Kim, Pill-Soo,Choi, Geun-Soo 한국조명전기설비학회 2004 조명·전기설비학회논문지 Vol.18 No.6

본 논문에서는 전기자동차 및 전기철도 등 대용량 구동 시스템에 응용 가능한 3상 ZCS(Zero Current Switching) 인버터에 관하여 논하였다. 기존의 경우 인버터는3상 유도전동기의 속도, 위치 및 토크특성의 개선을 위해 주로 연구되었으나, 3상 유도전동기의 효율 향상에 대한 연구는 미비한 실정이다. 본 연구에서는 기존의 컨버터 분야(DC-DC, AC-DC)에 적용하였던 소프트 스위칭 기법을 인버터 분야(DC-AC)에 적용하여 유도 전동기 구동을 위한 인버터 시스템의 효율 향상을 도모하고자 한다. 또한 제안된 인버터의 동작원리, 해석 및 특성에 대해서 논하였으며, IGBT를 사용하여 입력 DC 200[V], 출력 3HP (2.2[kW]) 3상 2극 유도전동기 구동을 위한 시작품을 제작, 5[KHz]에서 실험하였다. This paper um%n three phase XCS(Zero Current Switching) inverter circuits for large power application, example electric vehicles(EV), electric trains and so on. Previous studies were interested in improving speed, position and torque control but study of improvement efficiency was rare. This paper a soft-transition control strategy for inverter(DC-AC) circuit for induction motor driving of improvement efficiency. The principle of operation, feature and design consideration is illustrated and verified through the experiment with 2.2[kW] 5[KHz] IGBT based experimental circuit.

LLC Resonant Converter with High Voltage Gain Using Auxiliary LC Resonant Circuit

Dong-Kwan Kim,Cheol-O Yeon,Jae-Hyun Kim,Yeonho Jeong,Gun-Woo Moon 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

To design a LLC resonant converter optimally in the wide input voltage, the LLC resonant converter with a high voltage gain using an auxiliary LC resonant circuit is proposed. The auxiliary LC resonant circuit operates as a variable inductor, and it is represented as an effective magnetizing inductance combined with the magnetizing inductance. In the nominal state, the auxiliary LC circuit provides a high effective magnetizing inductance to minimize the primary circulating current for a high efficiency. During the hold-up time, the auxiliary LC circuit leads the effective magnetizing inductance to be reduced to obtain the high voltage gain. Therefore, an optimal design of the LLC resonant converter, which reduces the primary conduction loss and switching loss, is possible. The proposed converter is verified by experimental results with a 330- 390V input 56V/350W output prototype.

Balancing control scheme of DC‑link capacitor voltages for five‑level hybrid T‑type inverters without auxiliary circuit

Min‑Seok Kim,Dong‑Choon Lee 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.3

In this paper, a balancing control scheme of DC-link capacitor voltages for five-level hybrid T-type (5L-HT) inverters is proposed, where existing auxiliary balancing circuit is eliminated. The 5L-HT inverter has a significant advantage of the reduced number of devices compared with other five-level inverter topologies. However, this inverter requires an auxiliary balancing circuit, which is used to rectify the voltage imbalance at the DC-link capacitors, and thus negates the competitiveness of this topology in terms of device count and converter volume. To eliminate the auxiliary circuit, a carrier-overlapped PWM (COPWM) is applied in place of the conventional level-shifted PWM (LSPWM) to control the neutral-point currents, where the duty ratios of switches are adjusted by PI controllers. As a result, although the THD of the output voltage is rather increased, the cost and volume are saved by 27% and 52%, respectively, for a 1-MW/6.6-kV system. The effectiveness of the proposed balancing control method for the 5L-HT inverter has been verified through the simulation and experimental results for the prototype hardware.