• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.365-374
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• 1998

The SHE(Selected Harmonic Elimination) PWM scheme which eliminates specific lower order harmonics can generate h high quality output waveforms in 3-level PWM inverters. However. its application has limited since SHE switching a angles cannot be calculated on-line by a microprocessor-implemented control system. Based on off-line optimization. in which multiple SHE solutions were found and analysed for 2 to 5 switching angles per quarter in the 3-level SHE PWM pattern. this paper presents an algebraic algorithm for an ordinary microprocessor to calculate approximate SHE S switching angles on-line with such high resolution that it makes no practical difference between the accurate and the a approximate SHE switching angles. By employing the variable of the dc-link voltage Vdc' the proposed SHE PWM p pattern can ideally compensate the dc input fluctuation together with selected harmonics eliminated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1751-1758
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• 2003

This paper describes speed control of a permanent split capacitor single phase induction motor using SHE PWM inverters. The inverter is controlled by V55 microprocessor and its range is larger than other systems. Due to the V/F control with SHE(Selected Harmonic Elimination) PWM, continuously variable speed is attained and THD(Total Harmonic Distortion) is decreased. This is verified by simulations and experimental results.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1978-1981
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• 1997

This paper describes several PWM method for harmonics reduction in GTO inverter. The analysis and simulations of PWM techniques are carried out. The simulation results demonstrate that the programmed PWM methods(SHE PWM) are superior to the sine-modulated PWM method. The selected harmonic elimination (SHE) PWM scheme which eliminates specific lower order harmonics can generate high quality output waveform in PWM inverter.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.1-4
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• 2003

This paper proposes a method of voltage control for three-phase multilevel H-bridge inverters with selective harmonic elimination (SHE) PWM The full-bridge configuration of H-bridge inverter cells enables voltage control with a fixed PWM pattern by means of phase shifting between the legs, which greatly simplifies the control while maintaining the harmonic elimination characteristics. The series combination of the cells in multilevel configuration can be exploited to further improve the hormonic elimination characteristics with proper phase shifting between the ceil volitage. A complexor-based control method is introduced to control the magnitude and phase angle of cell voltages that form three-phase multilevel output voltages. Simulation results show that the proposed method along with SHE PWM would provide satisfactory performance in spite of its simplicity.

• 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 the Korean Institute of Telematics and Electronics
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• v.27 no.9
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• pp.1427-1435
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• 1990

This paper proposes the Selected Harmonic Elimination Pluse Width Modulation (SHE PW) scheme toreduce the ahrmonic components of source line current. To eliminate the low order harmonics which affects the source dominatly, we apply the Fourier series analysis to line current waveforms and then find out the switching patterns using the SHE PWM scheme. In addition to the analysis of harmonic effects, the three phase filter circuit is used to reduce high order harmonics. For the experimental realization, the converter circuit with power Transistor(PTR) is designed and the Pulse Time Control(PTC) is applied. The line current and the load voltage are measured under the condition of three phase application, highly inductive load.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.5
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• pp.450-456
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• 2014

In HVDC converters that employ a line-commutated control, reactive power is absorbed by the rectifier and inverter terminals during AC/DC conversion. An AC filter usually consists of filters and large shunt capacitors to supply reactive power to the HVDC station. When STATCOM is used to supply reactive power to the HVDC system with AC filter, the low-order harmonics generated from STATCOM can result in a resonance between the shunt capacitor and AC network. Therefore, a control strategy based on selective harmonic elimination is adopted to minimize the low-order harmonics from STATCOM. The cancellation of harmonic instabilities is verified through simulations in PSCAD/EMTDC.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1037-1050
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• 2018

This paper presents a novel reconfigurable selective harmonic elimination technique to control harmonics over a wide range of Modulation Indexes (MI) in Multi-Level Inverter (MLI). In the proposed method, the region of the MI is divided into various sectors and expressions are formulated with different switching patterns for each of the sectors. A memetic BBO-MAS (Biogeography Based Optimization - Mesh Adaptive direct Search) optimization algorithm is proposed for solving the Selective Harmonic Elimination - Pulse Width Modulation (SHE-PWM) technique. An experimental prototype is developed using a Field Programmable Gate Array (FPGA) and their FFT spectrums are analyzed over a wide range of MI using a fluke power logger. Simulation and experimental results have validated the performance of the proposed optimization algorithms and the reconfigurable SHE-PWM technique. Further, the sensitivity of the harmonics has been analyzed considering non-integer variations in the magnitude of the input DC sources.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1829-1838
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• 1989

This paper is proposed one method of the exact optimal switching pattern of Selected Harmonic Elimination(SHE) Pulse Width Modulation(PWM). It defined Harmonic Elimination Band (HEB) at Constant Voltage(CV) and sought all solutions which are included HEB. Then, it calculated the Generalized Klirr Factor(GKF) beling to this solution and decided the optimal switching pattern which is minimized GKF. This optimal switching solution is used as initial condition of Newto Raphson(NR) method of decided easily switching pattern at Variable Voltage(VV). We desined the inverter by Power Transister(PTR) and implemented variable speed drive of Induction Motor(IM) in order to verify the validity of this theoretical proposition, then shown this results by comparison and analysis.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.317-321
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• 1989

The fully digitalized inverter has some difficulties in implementation because of the limitation of available memory capacity and computation time. In this paper schemes suitable for a one-chip microprocessor-based realization, which linearize notch angles of selected harmonic elimination (SHE) PWM, are presented. Also the detailed description of the scheme along with the realization is described. The simulation and experiment results show that proposed schemes have the predicted advantages such as good voltage waveforms and a memory-saving.