• Journal of Electrical Engineering and Technology
• /
• 제10권3호
• /
• pp.905-915
• /
• 2015

Two PWM techniques using space vector pulse-width modulation (SVPWM) are proposed for a two-phase permanent magnet synchronous motor (PMSM) driven by a two-phase eight-switch inverter. A two-phase motor with two symmetric stator windings is usually driven by a two-phase four-, six-, or eight-switch inverter. Compared with a four- and six-switch inverter, a two-phase eight-switch inverter can achieve larger power output. For two-phase motor drives, the SVPWM technique achieves more efficient DC bus voltage utilization and less harmonic distortion of the output voltage. For a two-phase PMSM fed by a two-phase eight-switch inverter under a normal SVPWM scheme, each of the eight PWM trigger signals for the inverter have to be changed twice in a cycle, causing a higher PWM frequency. Based on the normal SVPWM scheme, two effective SVPWM schemes are investigated in order to reduce the PWM frequency by rearranging four comparison values, while achieving the same function as the normal PWM scheme. A detailed explanation of the normal and two proposed SVPWM schemes is illustrated in the paper. The experimental results demonstrate that the proposed schemes achieve a better steady performance with lower switching losses compared with the normal scheme.

• 전력전자학회논문지
• /
• 제10권4호
• /
• pp.339-346
• /
• 2005

본 논문에서는 3-레그 2상 인버터의 새로운 PWM방식을 제안하였다. 기존의 3-레그 인버터의 PWM방식은 전형적인 SVPWM 방식을 적용하여 PWM 방식이 복잡하다. 3-레그 2상 인버터를 "중성점이 있는 4-레그 인버터"의 등가회로라고 할 때 3-레그 인버터에서 형성되는 6개의 섹터는 4개의 섹터로 축소되며, 각 영역에서는 SYPWM 방식 대신 단순화된 정현파형 PWM방식을 적용할 수 있다. 각 레그의 스위치마다 스위칭 시간을 계산하는 스위칭 패턴을 제시하였다. 제안된 ,3-레그 인버터의 PWM방식에 대한 타당성을 확인하기 위해 모의 실험과 실험이 실행되었다.

• 전력전자학회논문지
• /
• 제10권4호
• /
• pp.331-338
• /
• 2005

본 논문에서는 2상 유도전동기의 가변속장치인 2-레그 및 4-레그 2상 인버터의 PWM 방식을 제안하였다. 기존의 SVPWM방식을 2-레그 인버터에 적용하기가 복잡하나, 본 논문에서는 캐리어 삼각파 PWM방식으로 단순화시켰다. 4-레그 인버터의 경우 전압벡터가 16개가 되어 전형적인 공간전압벡터이론을 적용하기가 복잡하다. 따라서, 본 논문에서는 이를 대신하여 2-레그 인버터형 삼각파 PWM방식을 기본으로 하여 4-레그 인버터에 적용할 수 있는 삼각파 PWM파형으로 단순화하였다. 제안된 2상 PWM방식에 대한 타당성을 확인하기 위해 모의 실험과 실험이 실행되었다.

• Journal of Electrical Engineering and Technology
• /
• 제8권5호
• /
• pp.1107-1115
• /
• 2013

A new PWM technique for a two-phase BLDC motor fed by a two-phase eight-switch inverter is proposed in this paper. It is well known that a two-phase eight-switch inverter can significantly improve power output compared with a two-phase six-switch inverter in a two-phase motor drive. To drive the two-phase BLDC motor simply and effectively, two normal PWM strategies are investigated to manage speed regulation. However, under the conditions of low speed and light load, especially during the braking process, the current in a short time of one period is near zero, which is a discontinuous waveform every half period. To solve it, a novel PWM technique is investigated to improve the operational performance of normal technique. Using the new PWM scheme, the current continues every half period and the braking performance is improved. The effectiveness of the proposed PWM method is verified through the experiments.

• 전력전자학회논문지
• /
• 제7권1호
• /
• pp.1-10
• /
• 2002

본 논문에서는 2상 인버터용 공간전압벡터 PW 방식을 제안하였다. 제안된 2상 공간전압벡터 PWM 방식은 2상 유도전동기에 적용할 수 있다. 2상 공간전압벡터 방식을 사용하는 2상 인버터는 4개의 공간 전압벡터를 발생하나 영 전압 벡터는 만들 수 없다. 2상 인버터에서는 4개의 공간 전압벡터를 조정하여 기본 전압벡터를 실현한다. 또한, 2상 공간전압벡터방식에 의해 최적의 PWM 전압파형을 만들기 위한 대칭변조방식이 제안되었다. 제안된 2상 공간 전압벡터방식에 대한 타당성을 확인하기 위해 시뮬레이션과 실험이 실행되었다.

• Journal of Power Electronics
• /
• 제16권2호
• /
• pp.498-511
• /
• 2016

This paper presents a single-phase five-level inverter controlled by two novel pulse width modulation (PWM) switching techniques. The proposed PWM techniques are designed based on minimum switching power loss and minimum total harmonic distortion (THD). In a single-phase five-level inverter employing six switches, the first proposed PWM technique requires four switches to operate at switching frequency and two other switches to operate at line frequency. The second proposed PWM technique requires only two switches to operate at switching frequency and the rest of the switches to operate at line frequency. Compared with conventional PWM techniques for single-phase five-level inverters, the proposed PWM techniques offer high efficiency and low harmonic components in the output voltage. The validity of the proposed PWM switching techniques in controlling single-phase five-level inverters to regulate load voltage is verified experimentally using a 100 V, 500 W laboratory prototype controlled by dspace 1103.

• Journal of Power Electronics
• /
• 제9권4호
• /
• pp.593-603
• /
• 2009

This paper proposes and describes the design and operational principles of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and a significant suppression of load harmonics contents are obtained at the inverter output. The harmonics content of the proposed multilevel inverter can be reduced by half compared with two-level inverters. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic distortion. The full-bridge power switches of the classical three-phase inverter operate at the line frequency of 50Hz, while the auxiliary circuit switches operate at twice the line frequency. To validate the proposed topology, both simulation and analysis have been performed. In addition, a prototype has been designed, implemented and tested. Selected simulation and experimental results have been provided.

• 전기학회논문지
• /
• 제60권1호
• /
• pp.78-84
• /
• 2011

In this paper, the switching frequency and THD for the reduction instead of traditional single phase inverter using a new type of central arm of the single phase inverter is proposed. The proposed single phase inverter topology, the existing one to add a arm by two-way central switch 3-level output voltage can be raised and, central arm, especially one or two of the switches by using a switch to the diode current switching algorithm was simplified. During the dead time because of this, depending on the direction of the current level does not appear in any other existing level compared to the inverter output voltage level of the THD has the advantage that less can be. The simulation and experimental results verified the validity of the proposed topology.

• 반도체디스플레이기술학회지
• /
• 제17권3호
• /
• pp.90-94
• /
• 2018

In this paper, we applied a three-level T-type inverter with the one more voltage level than two-level inverter. However, the three-level T-type inverter has a systematic problem with voltage unbalances. So neutral point control is essential. Therefore, the voltage unbalance problem of the three - phase inverter was confirmed to be controlled within 5V using the neutral point control algorithm in charge and discharge mode. In addition, total harmonic distortion was reduced in three phases (u phase, v phase, w phase) when neutral point control was performed in charging mode and also in three phases (u phase, v phase, w phase) in discharge mode. In this paper suggests a neutral point control algorithm to solve the voltage unbalance of a three-level T-type inverter, and shows the improvement of the performance of the proposed algorithm through experiment.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제55권1호
• /
• pp.47-53
• /
• 2006

In this paper, a simple scheme compensating for the effect of dc-link ripple voltages on output voltage of two-leg and three-phase PWM inverters is proposed, where single-phase half-bridge PWM convertor and two-leg inverter are used. The voltage at neutral point of the dc-link is controlled so that the upper-half of do-link voltage is equal to the lower-half voltage in average concept. However, the effect of the do-link ripple voltage results in the inverter output voltage and current distortion. This effect can be eliminated by introducing a compensation voltage in switching time calculation. Also, the inverter dead time should be compensated for sinusoidal output waveform. The proposed scheme has been verified by experimental results which were obtained from the V/F constant operation of the induction motor fed by two-leg inverter.