• Title, Summary, Keyword: PWM

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New Optimal PWM Scheme for Minimizing the Harmonic Effects of VSI-PWM Inverter (VSI-PWM 인버터의 고주파 영향을 최소화하기 위한 새로운 Optimal PWM 방식)

  • 이윤종;이일형;정동화
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.15 no.11
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    • pp.886-897
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    • 1990
  • This paper is proposed new optimal PWM scheme is based on a defined linear relationship between the successive pulsewidths of the PWM pattern. The calculation of the pulsewidths in the new PWM scheme is caried out without referring to the equations of CW and MW. With this scheme the PWM pattern for microprocessor controlled inverters can be composed easily by obtaining the optimal increment in sucessive pulsiwidths of the pattern. Furthmore, the harmonic level at the output of PWM inverter are always very low because this PWM pattern is selected on the basis of minimum THD. Theis scheme is applied to 1(Hp), three phase induction motor, and compared with conventional regular PWM scheme. The results of calculations and experiments show that new optimal PWM scheme could provide an effective generalized approach for minimization of harmonics in the VSI-PWM inverter.

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A Design of digital PWM controller for automotive brake solenoid valve (자동차 제동 솔레노이드 밸브용 디지털 PWM 컨트롤러 설계)

  • Kim, Dong-hyeon;Shin, Changsik;Seo, Jin-ho;Shin, Kyung-wook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.152-155
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    • 2014
  • This paper describes a design of digital PWM controller for automotive brake solenoid valve which is used in ABS/ESC SoC. The PWM controller which consists of 12 channels supports both direct control and PI control. Six channels in direct control mode make consistent PWM signals according to duty ratio setting, and the others in PI control mode make PWM signals with constant current depending on current setting. The PWM controller also has functions including solenoid valve open detection, Dither and PWM phase shift. The PWM controller having 44,779 gates is fabricated using a 0.18um CMOS process, and test results show that all the functions are correct.

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Space Vector Modulation in PWM Inverters and PWM Rectifiers (PWM 인버터와 PWM 정류기에서 공간벡터변조)

  • 권봉환;김한태
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.7
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    • pp.742-752
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    • 1992
  • In this paper, a space vector concept is generalized for PWM(pulse-width modulated) inverters and PWM rectifiers with current link and voltage link respectively. Through representing three-phase variables as a space vector, we propose space vector modulations for PWM voltage and current source inverters, and PWM rectifiers with current link and voltage link. For these types, switching states of the switches are systematically analyzed from tables. It is shown in three-phase PWM rectifiers that power factor of the line current and output dc voltage can be controlled arbitrarily. The PWM rectifier with current link is also given as an example system.

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PWM Method with Low d-axis Current Ripple for reducing Input Current THD at Light Loads in Three Phase PWM Rectifier (3상 PWM 정류기의 경부하시 입력전류 THD 저감을 위한 d축 전류리플 저감 PWM 방법)

  • Jin, Yong-Sin;Shin, Hee-Keun;Kim, Hag-Wone;Cho, Kwan-Yuhl
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.6
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    • pp.478-485
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    • 2012
  • In this paper, a new PWM method is proposed to reduce the input current harmonics of 3 phase PWM rectifier. In the conventional carrier comparison PWM method, a triangular wave is generally used as the carrier wave. However, the large d-axis current ripple by the triangle carrier wave may be a source of large input current THD(Total Harmonic Distortion). In this paper, a new carrier comparison PWM method with saw tooth wave is proposed. Depending on the sector where the voltage command vector places, one of the rising or falling saw tooth wave is selected. To reduce the switching losses of the saw tooth carrier PWM, the discontinuous PWM is also presented. The proposed PWM method can reduce the d-axis current ripple as well as the switching losses. The performance of the conventional and proposed PWM methods is verified by the simulation and experimental results.

Novel PWM Methods for Two-Leg and Four-leg Two-Phase Inverter Fed Two-Phase Induction Motor (2상 유도전동기 구동 2상 인버터를 위한 새로운 PWM제어방식 I - 2-레그 타입 및 4-레그 타입의 경우 -)

  • Jang Do-Hyun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.4
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    • pp.331-338
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    • 2005
  • In this paper the novel pulsewidth modulation(PWM) technique for the two-leg and four-leg two-phase inverter is proposed. The conventional space vector PWM technique for two-phase inverter was complex. The proposed PWM for two-leg inverter, which is used by sinusoidal PWM method, is simpler than the conventional SVPWU technique. Also, a simple PWM technique for four-leg two-phase inverter is proposed. Such PWM technique is based on PWM technique for two-leg inverter. Practical verification of theoretical predictions is presented to confirm the capabilities of the new techniques.

A Study on the PWM Pattern for Harmonics Reduction in GTO Inverter (GTO 인버터의 고조파 저감을 위한 PWM 패턴에 관한 연구)

  • Cha, Min;Park, Young-Jeen;Hong, Soon-Chan
    • Proceedings of the KIEE Conference
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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.

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Inverter Drives Adopting the Two-Phase Space Vector SRP-PWM Scheme with Fixed Switching Frequency (고정 스위칭 주파수를 갖는 2상 공간벡터 SRP-PWM기법을 적용한 인버터 구동 시스템)

  • 정영국;위석오;임영철;양승학
    • The Transactions of the Korean Institute of Power Electronics
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    • v.8 no.3
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    • pp.230-238
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    • 2003
  • In this paper, Inverter drives adopting 2 phase space vector SRP-PWM (Separately Randomized Pulse Position PWM) with fixed switching frequency is proposed. The proposed 2 phase space vector SRP-PWM scheme is based on the 3 phase SRP-PWM. In the proposed SRP-PWM scheme, each of two phase pulses is located randomly in each switching interval. The experimental results show that the voltage and acoustic noise harmonics are spread to a wide band area. Also, the performance of the proposed 2 phase SRP-PWM and the conventional center aligned SVM are compared to each other. In result, the speed response is nearly similar to each other from the viewpoint of the v/f constant control.

MRSF-PWM Method for Acoustic Noise Reduction of Traction Motor Drive Systems (견인전동기 구동시스템의 소음 저감을 위한 MRSF-PWM 방식)

  • 홍순찬;서영민
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.3
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    • pp.262-271
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    • 2002
  • In PWM inverters used in traction motor drive systems, the switching frequency is restricted by their large power capacity and thus the electromagnetic acoustic noise is generated. To reduce such an audible noise, the new MRSF-PWM(Modified Random Switching Frequency PWM) method is proposed. In the Proposed MRSF-PWM method, both triangular wave and sawtooth wave are used together as carrier waves for harmonic diffusion and reference wave is generated by injecting 3rd harmonic into the stone wave to expand the linear control region of output voltages. To verify the validity of the proposed MRSF-PWM method, computer simulations are carried out. And the results show that the MRSF-PWM method is more excellent than other RPWM methods in the aspects of both linearity and harmonic diffusion md more effective than SPWM(Sinusoidal PWM) method for the reduction of an audible noise.

Comparative Analysis of Offset Voltage PWM and $V_{max}-V_{mid}$ PWM Method for 3 Phase Matrix Converter (3상 매트릭스 컨버터에 사용되는 옵셋전압 PWM 방법과 $V_{max}-V_{mid}$ PWM 방법의 비교분석)

  • Cha, Han-Ju;Kim, Woo-Jung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.2
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    • pp.285-291
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    • 2009
  • In this paper, comparative analysis of offset voltage PWM method and $V_{max}-V_{mid}$ PWM method for three-phase matrix converter is addressed by using a simple analytical and graphical method. Offset voltage PWM method calculates PWM patterns in terms of offset voltage and variable slope of carrier, and it simplifies matrix converter modulation algorithm significantly. $V_{max}-V_{mid}$ PWM method generates patterns by using two phases and maintaining a remaining phase to base phase, and it is implemented in the industrial products. The most important performance criterion of modulation method is a magnitude of current ripples and it is analytically modelled. The graphical illustration of theses complex multivariable functions make per-carrier cycle and per fundamental cycle behavior of two PWM methods understood. Two modulation methods are analysed with the analytical formulas and graphics, and the analysis shows offset voltage PWM method is superior to $V_{max}-V_{mid}$ PWM method with respect to input current ripples and output voltage ripples.

Evaluation of Trapezoidal PWM Inverter using a new Harmonic Torque Factor (새로운 고조파 토오크 평가함수에 의한 Trapezoidal PWM 인버터의 평가)

  • Lee, Chi-Hwan;Koo, Bon-Ho;Kwon, Wu-Hyen
    • Proceedings of the KIEE Conference
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    • pp.754-756
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    • 1987
  • In this paper, a new Harmonic Torque Factor(HTF) that represents torque ripple of induction motor is proposed. Trapezoidal PWM is analyzed to torque ripple by HTF and than we obtain optimum triangular factor at some carrier ratio. Six-step, sinusoidal PWM and Trapezoidal PWM are compared and evaluated for choosing a good control strategy of PWM inverter. It turns out that six-step inverter is better than sinusoidal PWM and Trapezoidal PWM when their carrier ratio is 9, and Trapezoidal PWM is superior to sinusoidal PWM. At induction motor is driven by PWM inverter, torque ripples are investigated by computer simulation using d-q two axis model. It is proved that a new Harmonic Torque Factor ix valid.

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