Open AccessA New Method for Maintaining Constant Dither Amplitude in Low Frequency PWM
Author(s) -
Hoon Kang,
J. Park,
J. Cho,
J. Kim,
Jong–Hoon Oh
Publication year - 2017
Publication title -
advances in electrical and computer engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.254
H-Index - 23
eISSN - 1844-7600
pISSN - 1582-7445
DOI - 10.4316/aece.2017.01013
Subject(s) - dither , amplitude , pulse width modulation , constant (computer programming) , pulse amplitude modulation , computer science , control theory (sociology) , mathematics , electronic engineering , physics , power (physics) , pulse (music) , telecommunications , engineering , control (management) , bandwidth (computing) , artificial intelligence , quantum mechanics , detector , programming language
Various controls for fluid flow and pressure are now required in related industries, and the pulse width modulation (PWM) and dithering techniques have become essential for the proportional control of solenoids. However, there is a fatal drawback when the dither current signals are generated as a by-product of low frequency PWM. That is, the average current and the dither amplitude in low frequency PWM cannot be controlled independently. Therefore, a new method for maintaining constant dither amplitudes is proposed in this paper. Throughout the mathematical analysis, the effect of PWM frequency and duty cycle on the average current and dither amplitude was investigated, and the analysis result was validated by electrical experiments. Based on the mathematical analysis, a new method that properly varies both the duty cycle and the PWM frequency to obtain the desired average current and constant dither amplitude was established and verified. This method requires only the calculations for determining the proper PWM frequency and duty cycle, so it is possible to improve the performance of a proportional solenoid valve without additional devices or cost