Hi,
I have tried to do some fixed-step equation solving for power converters, and I have encountered a very weird phenomenon : a unit assigned to "0" without being asked.
here is a file that reproduces the problem. The "physical" model is a boundary-mode buck converter. The switch is on (PWM=1) for a fixed duration (ton), then off (PWM=0) until the current in the inductor reaches 0.
When the PWM is set to 1, no problem, but when it is set to 0, Mathcad strangely sets it to 0s. If I specify a unit, this units "overrides" the s. If a unit is set to the "1" condition, it applies automatically to the "0" condition too (???). The only way I have found to get rid of this is to do PWM:=PWM/SIUnitsOf(PWM), but it would be much better if it didn't force some unwanted unit in the first place.
Any idea where that comes from, and how to prevent that from happening ?
Thanks