[전력전자]Implementation of a DSP Controlled Random Switching Frequency
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이 논문은 전력전자 산하[ICPE`01]에서 2001년도에 발표되었던 Random PWM에 관한 영문판 논문이며 전력전자를 전공하시거나 Random PWM에 관해 연구하시는분에게는 매우 필요한 자료가 될것입니다. 건투를 빕니다!목차
Abstract1. Introduction
2. Randomized switching frequency PWM
3. Implementation
4. Experimental results
5. Conclusions
References
본문내용
The electromagnetic noise due to the PWM switching is generated with narrow band high frequency, which causes communication obstacle and unpleasant high frequency audible noise. As a result of psychological study, it is known that the narrow band noise is more unpleasant than the broad band one[2].The RPWM technique is a new and effective method to let the inverter fed ac motor drive possess low acoustic noise and mechanical vibration when lower switching frequency is chosen. The chief reason is that the harmonic spectrum of a RPWM inverter can be dispersedly and continuously distributed[3]. Many approaches can be applied to achieve this goal. Roughly, the existing RPWM techniques can be classified into three groups, namely randomized switching frequency (RSF-PWM)[4-6], randomized pulse position (RPP-PWM)[2,7-8] and random switching(RS-PWM)[9]. Although many RPWM schemes have been reported, RSF-PWM is the most popular technique. RSF-PWM can be achieved through randomly varying the switching number in a cycle [4], the slope of the triangular wave[5] or the radian angle of the space vector PWM[6]. Especially, RSF-PWM scheme proposed by Habetler and Divan[5] is very easy and simple to implement. But, in this approach the band limited RPWM generator is implemented using a lookup table, whose contents have been generated by off line. That is, a large quantity of periodic random numbers can be computer generated and stored in some type of ROM.Thus, to solve the above-mentioned problems, in this study a DSP controlled random switching frequency PWM inverter drive system is implemented. Real-time RPWM along with the speed control was achieved by high speed DSP TMS320C31. Since RPWM is being generated using a real time DSP, a lookup table is no need and the band unlimited RPWM generator is implemented. Using randomly changed switching frequency of the inverter, the voltage and current harmonics are spread to a wide band area. Also, the power spectrum of the audible acoustic switching noise was spread to create a more appealing, less annoying sound.
참고 자료
References[1]C.M. Liaw, Y.M. Lin and K.I. Hwu,” Analysis, design and implementation of a random frequency PWM inverter”, IEEE Trans. Power Electron., vol.15, no. 5, pp.843-854, 2000.
[2] Y.G. Jung, S.H. Na and Y.C. Lim,” A new space vector random PWM schemes for induction motor drives’, KIPE International Conference on Power Electronics, ICPE’01( Seoul Korea), pp.160-168. 2001.
[3]C.M. Liaw and Y.M. Lin, ”Random slope PWM inverter using existing system background noise: Analysis, design and implementation”, IEE Pro. Electr. Power Appl., vol.147, no.1, pp.45-54,2000.
[4]A. M. Trzynadlowski, J. K. Pedersen, R. L. Kirlin and S. Legowski, "Space vector PWM technique with minimum switching losses and a variable pulse rate", IEEE Trans. Ind.Applicat., vol.44, no.2,pp.173-181,1997.
[5]T.G. Habetler and D. M. Divian, "Acoustic noise reduction in sinusoidal PWM drives using a randomly modulated carrier", IEEE Trarns. Power Electron., vol. 6, no. 3, pp. 356-363, 1991.
[6]F. Blaabjerg and J. K. Pedersen, "Implementation and test of a digital quasi-random modulated SFAVM PWM in a high performance drive system", in Proc. Conf. Rec. 1991 IEEE IECON, pp.265-270.1993.
[7] R.L. Kirlin, S. Kwok, S. Legowski and A. M. Trzynadlowski, "Power spectra of a PWM inverter with randomized pulse position", IEEE Trans. Power Elctron., vol.9, no.5, pp.463-471,1994.
[8] A. M. Trzynadlowski, S. Legowski and R. L. Kirlin, "Random pulse width modulation technique for voltage controlled power inverters", IEEE IA Conf. Rec, pp.863, 1987.