• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.1042-1046
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• 1998

A new soft switching isolated bi-directional phase shifted pulse width modulation (PSPWM) dc/dc converter is presented. Due to the use of the energy recovery snubber, the isolated bi-directional PSPWM dc/dc converter has a significant reduction of switching losses in the switching devices of the primary and secondary side bridge, respectively. The proposed soft switching bi-directional PSPWM FB dc/dc converter provides an energy recovery snubber which consists of two fast recovery diodes, a resonant capacitor and a resonant inductor. The complete operating principles and simulation results will be presented.

• 전력전자학회논문지
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• 제15권1호
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• pp.43-51
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• 2010

본 논문에서는 고전압 전동기 가변속 장치인 H-브릿지 멀티레벨(H-Bridge Multi-Level; HBML) 인버터를 이용한 유도 전동기 벡터 제어시 인버터의 출력 전압 위상 지연 현상을 해석하고 전류 제어기의 보상 기법을 제시하였다. Phase-Shifted Pulse Width Modulation (PSPWM) 기법을 적용한 HBML 인버터는 개별 인버터 모듈이 독립적으로 동작할 수 있어서 확장성과 모듈화 능력이 향상되는 장점이 있다. 그러나 이러한 PSPWM을 적용한 HBML 인버터는 기준 전압과 실제 전압 사이에 위상 차이가 있기 때문에 출력 주파수에 대한 샘플링 주파수의 비율이 충분하지 않은 고속 영역에서 전류 제어기를 불안정하게 하는 원인이 된다. 전류 제어기의 불안정성은 기준 전압과 출력 전압의 위상 차이를 보상하는 제안된 방법을 추가함으로써 제거하였다. 본 방법은 인버터의 스위칭 주파수가 낮고, 전동기 속도가 높은 조건에서 PSPWM을 이용한 HBML 인버터 시스템에 효과적이며, 13레벨로 구성된 HBML 인버터로 구동되는 6,600[V] 1,400[kW] 유도전동기 실험을 통해 제안된 방법의 타당성을 입증하였다.

• 전력전자학회논문지
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• 제27권6호
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• pp.526-534
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• 2022

The modular multilevel converter (MMC) has been widely applied to various industrial areas because of its various advantages and structural characteristics. Therefore, many methods for synthesizing the output voltage of MMC have been studied. Among these methods, phase-shifted pulse width modulation (PSPWM) is frequently used in MMC systems because it has diverse merits, such as excellent output qualities even with a small number of cells and uniform power distribution among cells. In this study, the total harmonic distortion (THD) of the output voltage is analyzed in accordance with the number of cells in one arm of a single-delta bridge cell MMC in order to compare PSPWM methods in terms of the THD of the output voltage. The physical characteristics of the triangle and sawtooth carrier waves used for the PSPWM and the mathematical modeling of output voltage are introduced. Then, the obtained results are verified through real-time simulation of a 1 MW single-delta bridge cell MMC system.

• Journal of Power Electronics
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• 제18권4호
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• pp.1140-1153
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• 2018

The harmonic impedance characteristic of a traction power supply system (TPSS) is necessary for taking actions to suppress the high-order harmonic resonances caused by AC electric locomotives. This paper proposes a controllable harmonic generating method (CHGM) for measuring the TPSS harmonic impedance by injecting harmonic disturbances of different frequencies and amplitudes into the TPSS. This method applies phase shifted pulse-width modulation (PSPWM) and ensures that the undesired sideband harmonics can be negligible while the desired harmonic is both controllable and adjustable. Multiple harmonics can be emitted at the same time. The implementation of the method is also presented. Simulations are carried out to validate the performance of the proposed method. Finally, experimental results on a 5 H-bridge converters platform verified the effectiveness and feasibility of the proposed method.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권12호
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• pp.624-631
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• 2003

This paper presents a simple carrier symmetric method for the voltage balance of flying capacitors in FCMLI(flying capacitor multi-level inverter). To achieve the voltage balance of flying capacitors, the utilization of each carrier must be balanced during a half-cycle of the switching period such as PSPWM(Phase-Shifted PWM). However, the CRPWM(Carrier Redistribution PWM) method causes the fluctuation of flying capacitor voltages because the balanced utilization of carriers is not achieved. Moreover, it does not consider that the load current change has an influence on flying capacitor voltages by assuming that the current flows into the load. To overcome the drawbacks of CRPWM, it is modified by the technique that carriers of each band are disposed symmetrically at every fundamental period. Firstly, the CRPWM method is reviewed and the theory on voltage balance of flying capacitors is analyzed. The proposed method is introduced and is verified through the experiment result.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.606-610
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• 2003

This paper presents a simple carrier symmetric method for the voltage balance of flying capacitors in FCMLI(flying capacitor multi-level inverter). To achieve the voltage balance of flying capacitors, the utilization of each carrier must be balanced during a half-cycle of the switching period such as PSPWM(Phase-Shifted PWM). However, the CRPWM(Carrier Redistribution PWM) method causes the fluctuation of flying capacitor voltages because the balanced utilization of carriers is not achieved. Moreover, it does not consider that the load current change has an influence on flying capacitor voltages by assuming that the current flows Into the load. To overcome the drawbacks of CRPWM, it is modified by the technique that carriers of each band are disposed symmetrically at every fundamental period. Firstly, the CRPWN method is reviewed and the theory on voltage balance of flying capacitors is analyzed. The proposed method Is introduced and is verified through the experiment result.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.298-301
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• 2005

The flying capacitor voltage control of the flying capacitor multi-level inverter (FCMLI) is very important for safe operation. The voltage unbalancing of flying capacitors caused serious problems in safety and reliability of system. In the FCMLI, balancing problem of the flying capacitor has its applications limited. The voltage unbalance is occurred by the difference of each capacitors charging and discharging time applied to FCMLI. This paper investigates and analyzes multi-carrier PWM methods to solve capacitor voltage balancing problem. The Phase-Shift PWM (PSPWM) method that is commonly used, The Modified Carrier-Redistribution PWM (MCRPWM) method and The Saw-Tooth-Rotation PWM (STRPWM) method are discussed and compared with respect to switching state, balancing voltage of capacitors and output waveform. These three PWM methods are analyzed by using a flying capacitor three-level inverter and provided result through simulation. Finally, the harmonics about the output voltages of their methods are compared using the harmonic distortion factor (HDF).