• Journal of Power Electronics
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• 제19권1호
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• pp.201-210
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• 2019

This paper proposes a multimode hybrid control strategy that can achieve zero-voltage switching of primary switches and zero-current switching of secondary rectifier diodes in a wide input voltage range for full-bridge LLC resonant converters. When the input voltage is lower than the rated voltage, the converter operates in Mode 1 through the variable-frequency control strategy. When the input voltage is higher than the rated voltage, the converter operates in Mode 2 through the VF and phase-shift control strategy until the switching frequency reaches the upper limit. Then, the converter operates in Mode 3 through the constant-frequency and phase-shift control strategy. The secondary-side diode current will operate in the discontinuous current mode in Modes 1 and 3, whereas it will operate in the boundary current mode in Mode 2. The current RMS value and conduction loss can be reduced in Mode 2. A detailed theoretical analysis of the operation principle, the voltage gain characteristics, and the realization method is presented in this paper. Finally, a 500 W prototype with 100-200 V input voltage and 40 V output voltage is built to verify the feasibility of the multimode hybrid control strategy.

• Smart Structures and Systems
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• 제10권3호
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• pp.193-207
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• 2012

New insights into our previously proposed hybrid-type method for vibration control are highlighted in terms of energy analysis, such as the assessment of energy efficiency and system stability. The hybrid method improves the bang-bang active method by combining it with an energy-recycling approach. Its simple configuration and low energy-consumption property are quite suitable especially for isolated structures whose energy sources are strictly limited. The harmful influence of the external voltage is assessed, as well as its beneficial performance. We show a new chattering prevention approach that both harvests electrical energy from piezoelectric actuators and eliminates the displacement-offset of the equilibrium point of structures. The amount of energy consumption of the hybrid system is assessed qualitatively and is compared with other control systems. Experiments and numerical simulations conducted on a 10-bay truss can provide a thorough energy-efficiency evaluation of the hybrid suppression system having our energy-harvesting system.

• 한국산학기술학회논문지
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• 제14권3호
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• pp.1459-1466
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• 2013

최근 들어, 주변의 환경 분석을 보다 효과적으로 수행하기 위해서 많은 종류의 3차원 입체 카메라가 보급되고 있다. 본 논문에서는 주위 환경의 복잡도에 따라서 하이브리드 카메라의 수동형과 능동형 카메라를 적응적으로 스위칭함으로써 3차원의 영상정보를 보다 정확하게 추출할 수 있는 메커니즘을 제안한다. 제안된 방법에서는 먼저 초기영상을 받아들이고, 이 입력영상으로부터 주변의 환경을 대표할 수 있는 주요 특징인 밝기 특징과 텍스처 특징을 추출한다. 그런 다음, 추출된 밝기와 텍스처 특징값을 가장 잘 수용할 수 있는 카메라를 선택하는 규칙을 생성함으로써 하이브리드 카메라를 적응적으로 스위칭한다. 실험에서는 수동형과 능동형으로 구성된 하이브리드 입체 카메라를 구성하고, 제안된 적응적인 스위칭 알고리즘을 하이브리드 카메라에 적용하여 성능을 측정하기 위한 실험결과를 기술하며, 제안된 방법이 신뢰성 있게 동작함을 보여준다.

• Journal of Power Electronics
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• 제19권1호
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• pp.146-157
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• 2019

The inverter is an essential part of permanent magnet synchronous motor (PMSM) drive systems. The performance of an inverter is greatly influenced by its modulation strategy. Using a proper management of modulation strategies can guarantee high performance from a PMSM under various speed conditions. Switching between modulations is a pivotal technique that determines the performance of a PMSM. Most works on hybrid methods focus on two-level induction motors drive systems. In this paper, in order to improve the performance of PMSMs under various speed conditions, a hybrid method of a pulse width modulation (PWM) control scheme based on a neutral-point-clamped (NPC) three level topology was proposed. This hybrid PWM modulation comprised space vector PWM (SVPWM) and selective harmonic elimination PWM (SHEPWM). Under low speed conditions, the SVPWM is employed to cause the PMSM to start smoothly, and to obtain a rapid response from the control system. Under high speed conditions, the SHEPWM is employed to reduce the switching frequency and to eliminate particular current harmonics. Moreover, the harmonic characteristics of different modulations are analyzed to obtain a smooth transition between the SHEPWM and the SVPWM. Experimental and simulation results indicated the effectiveness of the proposed control method.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.758-761
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• 2003

전원장치의 소형화 핵심기술인 반도체 스위칭 기술을 이용하여 단일 전원을 사용하는 소형, 경량화 전자기기에 적합한 5 V/500 mA급 트랜스리스형 파워 모듈(transless type power module)을 설계하였다. 파워 모듈은 강압형 chopper 방식을 이용한 스위칭회로, 제어회로, 전압검출회로, 그리고 정전압 회로 둥으로 구성되어 있으며, 하이브리드-집적회로형(hybrid-IC type)으로 제작되었다. 본 연구에서 설계한 스위칭 레귤레이터 전원회로는 5 V/500 mA급 트랜스리스형 파워 모듈의 전기적 특성을 만족하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.261-265
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• 2005

본 논문에서는 하이브리드 자동차용 보조전원 공급이 목적인 DC-DC Converter에 대하여 기술하였다. DC-DC Converter는 차량 내의 헤드램프, 오디오, 각종 ECU등 전기/전자 부하에 전력을 공급하며 또한 12V 보조 배터리를 충전하는데 사용된다. 고주파 동작 조건하에서 유기되는 전자파 노이즈와 스위칭 손실을 저감하기 위하여 컨버터 토폴로지로 위상천이 영전압 풀브리지 방식을 적용하였으며 제어기의 용이한 보상 및 안정된 시스템 응답 특성을 위하여 슬로프 보상이 포함된 전류 모드 제어방식을 사용하였다 정전압/정전류 충전 제어 방식은 전기부하에 안정적인 전원공급과 보조 배터리의 안정적인충전을 보장한다. 초기의 회로 파라메타 설정 및 하드웨어 디버깅을 위하여 시뮬레이션 툴로 PSIM 6.0을 사용하였으며. DC-DC Converter에서 스위칭 소자의 발열문제는 Thermo Tracer 장비를 사용하여 개선하였다.

• 제어로봇시스템학회논문지
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• 제16권3호
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• pp.249-255
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• 2010

The paper proposes a new type of robust speed control strategy for permanent magnet synchronous motor by using PD-sliding mode hybrid control. The PD control has a good performance in the transient region while the sliding mode controller provides the robustness against system uncertainties. Taking advantages of the two control strategies, the proposed control method utilizes the PD control in the approaching region to the sliding surface and the sliding mode control near at the sliding surfaces. The chattering problem of the sliding mode controller is eliminated by applying the saturation function for the switching function of the sliding mode control. The stability of the sliding mode control is verified by using Lyapunov function with the proper selection of variable gains. It is shown that with this simple switching algorithm, stability of the overall hybrid control system is ensured. Through the simulations, the PD-sliding mode algorithm is shown to have a good performance in the transient response as well as being robust against disturbances. The robustness of the PD-sliding mode algorithm is further demonstrated against various external disturbances in the real experiments of SPMSM motor control.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.285-285
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• 2016

Resistive random access memory devices have been widely studied due to their high performance characteristics, such as high scalability, fast switching, and low power consumption. However, fluctuation in operational parameters remains a critical weakness that leads to device failures. Although the random formation and rupture of conducting filaments (CFs) in an oxide matrix during resistive switching processes have been proposed as the origin of such fluctuations, direct observations of the formation and rupture of CFs at the device scale during resistive switching processes have been limited by the lack of real-time large-area imaging methods. Here, a novel imaging method is proposed for monitoring CF formation and rupture across the whole area of a memory cell during resistive switching. A hybrid structure consisting of a resistive random access memory and a light-emitting diode enables real-time monitoring of CF configuration during various resistive switching processes including forming, semi-forming, stable/unstable set/reset switching, and repetitive set switching over 50 cycles.

• 전력전자학회논문지
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• 제22권4호
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• pp.360-368
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• 2017

This paper proposes the 80-kW high-efficiency bidirectional hybrid SiC boost/buck converter using droop control for DC nano-grid. The proposed converter consists of four 20-kW modules to achieve fault tolerance, ease of thermal management, and reduced component stress. Each module is constructed as a cascaded structure of the two basic bi-directional converters, namely, interleaved boost and buck converters. A six-pack hybrid SiC intelligent power module (IPM) suitable for the proposed cascaded structure is adopted for high-efficiency and compactness. The proposed converter with hybrid switching method reduces the switching loss by minimizing switching of insulated gate bipolar transistor (IGBT). Each module control achieves smooth transfer from buck to boost operation and vice versa, since current controller switchover is not necessary. Furthermore, the proposed parallel control using DC droop with secondary control, enhances the current sharing accuracy while well regulating the DC bus voltage. A 20-kW prototype of the proposed converter has been developed and verified with experiments and indicates a 99.3% maximum efficiency and 98.8% rated efficiency.

• Journal of Power Electronics
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• 제16권2호
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• pp.480-489
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• 2016

A novel hybrid carrier-based pulse width modulation (CBPWM) scheme that combines unipolar and dipolar modulations is proposed for single-phase three-level rectifiers, which are widely applied in railway traction drive systems. The proposed CBPWM method can satisfy the volt-second balancing principle in the complete modulation index region through overmodulation compensation. The modulation scheme features two modulation modes: unipolar and dipolar. The operation range limits of these modulation modes can be modified by changing the separation coefficient. In comparison with the traditional unipolar CBPWM, the proposed hybrid CBPWM scheme can provide advantageous features, such as lower high-order harmonic distortion of the line current and better utilization of switching frequency. The separation coefficient value is optimized to achieve the maximum utilization of these advantages. The experimental results verify the feasibility and effectiveness of the proposed hybrid CBPWM scheme.