LUO Xionglin, ZUO Ruixiang, FENG Aixiang, et al. Modified switch control with buffer heating stage in chemical process startup[J]. CIESC Journal, 2015, (2): 647-654.
LUO Xionglin, ZUO Ruixiang, FENG Aixiang, et al. Modified switch control with buffer heating stage in chemical process startup[J]. CIESC Journal, 2015, (2): 647-654.DOI: 10.11949/j.issn.0438-1157.20140923.
Chemical process startup is mostly a heating process
to satisfy the requirements of speed and stability
some researchers proposed Bang-Bang control combined with other control method for controlling the heating process
but due to strict requirements of Bang-Bang control on switching time and switching point
its practical application is not satisfactory. So based on Bang-Bang control
a buffer heating stage was added. Then the temperature control process could be divided into four parts: full width
zero brake
buffer heating and PID control. The rate of change of temperature was used as switching variable between buffer heating and PID control. In addition
modified switch control was converted to nonlinear programming problems
and switching points of the first three parts were optimized. Simulation comparison revealed that the control method not only avoided the problem caused by inproper selection of switching times and switching points
but overshoot was small and the process could be stabilized quickly.