Ramping limit of the unit on the first interval of start-up / last interval of shutdown
Equations q_rampUpLimit and q_rampDownLimit don't take into account that on the first interval of start-up (or last interval of shutdown), the ramping is only half of p_unit(unit, 'rampSpeedToMinLoad') (or p_unit(unit, 'rampSpeedFromMinLoad')). Shouldn't be a problem if unitCount=1 because q_maxUpward and q_maxDownward limit the generation level. However, ramping is not limited properly if unitCount>1.
Of course, if the unit reaches its min. load during just one interval, maxRampUp also affects the ramping limit on the first start-up interval. Same thing for shutdowns. In general, these shortcomings don't probably affect the results much, so this is not a very urgent issue. There are also other difficulties in the ramping constraints coming from assuming that v_gen is the average generation over the interval.