• Journal of Power Electronics
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• v.19 no.1
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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.

• Journal of Power Electronics
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• v.16 no.1
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• pp.340-350
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• 2016

A cascaded hybrid multilevel inverter including a reconfiguration technique for low voltage dc distribution applications is proposed in this paper. A PWM generation fault detection and reconfiguration paradigm after an inverter cell fault are developed by using only a single-chip controller. The proposed PWM technique is also modified to reduce switching losses. In addition, the proposed topology can reduce the number of required power switches compared to the conventional cascaded multilevel inverter. The proposed technique is validated by using a 3-kVA prototype. The switching losses of the proposed multilevel inverter are also investigated. The experimental results show that the proposed hybrid inverter can improve system efficiency, reliability and cost effectiveness. The efficiency of proposed system is 97.45% under the tested conditions. The proposed hybrid inverter topology is a promising method for low voltage dc distribution and can be applied for the multiple loads which are required in a data center or telecommunication building.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.11
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• pp.646-654
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• 1999

This paper deals with PWM patterns for harmonic reduction in inverter fed traction motors and the gear changing techniques for the variable speed drive of traction motor. GTOs are used as switching device of inverter because traction motor is a large load. To derive PWM rattern which can minimize the harmonics with the limited switching frequency, the output current and torque characteristic of SPWM and SHE PWM was analyzed. GTO inverter used for traction motor drive includes harmonics in the output current and torque by the limitation of switching frequency. However, the hybrid PWM method that adopt SPWM in the range of low frequency and SHE PWM in upper frequency range can achieve less harmonic characteristics in GTO inverters. If the traction motor is driven in variable speed by the proposed PWM pattern, 7 times of gear changing is needed. At the instant of the mode change, magnetic flux and torque may be altered and the large current flow. To reduce such an undesirable transient behavior, it is also presented the technique for the gear changing of inverter fed traction motor drive operated with the hybrid PWM. The results are verified by simulations and experiments.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.1
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• pp.71-81
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• 1995

In this paper, a new speed control scheme for induction motor drives that regular sampled PWM and harmonic elimination switching pattern over the full range of output speed is presented. The proposed scheme(hybrid scheme) provides three mode and guarantees smooth voltage boost. A detailed description of the scheme, along with the relalization aspect, is described. Moreover, methods of compensating for dead time and optical transmission system of drive signal are proposed and investigated. Finally, experimental investigation of hybrid scheme is presented.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.91-97
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• 2012

This paper presents a state space model of a two quadrant chopper and PWM inverter-fed Interior Permanent Magnet Synchronous Motor (IPMSM) drive system and its application to hybrid vehicles. The drive system has two different state equations for motoring and regenerating action. This paper presents a common state equation by using State Space Averaging method. Using this model of the IPMSM drive system, detailed simulation and controller design of the drive system, including PWM inverter switching, are given. The validity of this model and usefulness, according to a comparison among Maximum Torque/Ampere control, Maximum Torque/Flux control, and Maximum Efficiency optimization, are confirmed from simulation results.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1187-1189
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• 2000

This paper presents a high power-hybrid multilevel PWM rectifier with unity power factor. The features and advantages of the proposed PWM rectifier can be summarized as follows; 1) It realizes the high power high voltage AC/DC power conversion. 2) It uses no transformer which is bulky and heavy, 3) It has hybrid structure so that switching devices can be effectively utilized, 4) It produces high quality AC current even in high power high voltage applications, 5) The input power factor remains unity by simple modulation index control. The multilevel rectifier is analyzed by using the circuit DQ transformation whereby the characteristics and control equations are obtained.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.670-674
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• 2016

The control performance of hybrid PWM inverter using a phase current measurement is presented in this paper. The hybrid PWM technique consists of space vector pulse width modulation (SVPWM) and six-step voltage control operation. The SVPWM is performed to reduce the harmonic components in the low speed region, and the six-step modulation is applied to increase the maximum speed of the IPMSM in the high speed region. Therefore, it is possible to obtain a great performance in both the low speed range and high speed range. However, the six-step modulation cannot be completely implemented, since the inverter that includes the lag-shunt sensing method has an immeasurable current region. In this paper, a quasi-six-step modulation using a modified voltage vector is proposed. The validity and usefulness of the proposed PWM technique is verified by MATLAB/Simulink and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.5
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• pp.501-507
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• 2005

This paper proposes a Hybrid Random PWM(HRPWM) technique using a LF2407 DSP board in order to spread the power spectra of an induction motor. The proposed method is composed to the PRBS (Pseudo-Random Binary Sequence) with the Lead-Lag random bit and the random triangular carrier for the logical comparison. Also, a DSP generates the random number, the PRBS and the three-phase reference signal, a MAX038 chip operating as frequency modulator generates the random triangular carrier. For verification of the proposed method, the experiments were conducted with a three-phase adjustable speed a.c drives, and the results of simulations and experiments are presented.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.618-621
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• 2002

This paper proposes a static vu compensator using hybrid cascade 5-level PWM inverter, Circuit DQ transformation is used for modeling and analysis of the system, and it reveals the important characteristics and related equations of the system. Also, a multilevel PWM technique suitable to hybrid structure Is proposed for less harmonics in the input currents of the system. Finally, the validity of tile characteristics analysis is shown through PSIM simulations.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.762-765
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• 2005

본 연구에서는 유도 진동기의 파워 스펙트럼의 확산을 위한 LF2470 DSP기반 Hybrid Random PWM을 제안하였다. 제안된 방법은 Lead-Lag 랜덤 비트를 발생하기 위한 PRBS (Pseudo-Random Binary Sequence)와 PRBS와 논리적 비교를 위한 삼각파 랜덤 캐리어로 이루어진다. 또한 DSP에 의하여 랜덤 수 및 PRBS 그리고 3상 기준 정현파를 실시간으로 발생하며, DSP외부의 주파수 변조기 MAX038에 의하여 랜덤 주파수의 캐리어를 발생한다. 본 연구의 타당성 검증을 위하여 제안된 기법을 3상 유도전동기 구동장치에 적용하였으며, 종전의 방법과 전압 및 전류 그리고 전동기 소음 스펙트럼을 비교 검토하였다.