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<p class=MsoNormal>Hello,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I’m having a convergence error that seems to be rooted
in the PID controller. I was wondering if <span style='color:#1F497D'>anyone</span>
could shed some light on the subject.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I’m trying to model a long-haul truck sleeper cabin
climate control system. I’m using a Type 23 PID controller in
conjunction with a “seasonal switch” as the climate control
unit. The purpose of the seasonal switch is to turn the heater on
and the air conditioner off when the temperature drops below some low deadband
temperature and vice versa when the temperature rises above the high deadband
temperature. In other words, the purpose of this switch is to keep the
air conditioner from coming on during slight over-heating and the heater from
coming on during slight over-cooling. The deadband in the seasonal switch
is set by default to 5 degrees Celsius. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>When just this group of components is run, the output signal
from the PID controller and seasonal switch match just as they should (climate
controller.tpf). However, when a fuel-fired heater (Type 151, homegrown)
is added, the control signal starts doing some crazy stuff (Climate controller
with heater.tpf). The control signals, which should align nicely<span
style='color:#1F497D'>,</span> start diverging considerably. This (I
assume) creates the convergence error that stops the simulation after a little
more than an hour with the current settings. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Is there something inherent in the way I am trying to string
together these components that is making the solver diverge? Is there a
better way to go about it? I’m not looking for a total solution-
simply a pointer or two towards why the program is behaving as it is and what I
might do to get back on track. Please let me know if you need any other
files. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thank you in advance for your time,<o:p></o:p></p>
<p class=MsoNormal>Ethan Lust<o:p></o:p></p>
<p class=MsoNormal>301.405.8672 (desk)<o:p></o:p></p>
<p class=MsoNormal>757.636.8727 (cell)<o:p></o:p></p>
<p class=MsoNormal>University of Maryland<o:p></o:p></p>
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