Can power factor (PF) be scheduled in during a 24hour period

Good day,

The input to a controlled current source is fed by the attached power factor (PF) block and 1-D look-up data representing a load or irradiance. The reactive power produced by adjusting the PF setpoint is proportional to the active power generated over a 24hour period.

Is there a method to schedule the PF output by switching the signal on/off automatically during a pre-programmed time?

[Walter Roberson]

Suppose you had a hot sunny day, you are getting good irradiance. But with it being that hot, there is a chance of evening thunderstorms for anywhere from 2 minutes to 5 hours. Can you predict the evening irradiance with enough certainty to be able to change your signal during the daytime so that the end result of the 24 hour period has the desired characteristics ?

[Bill Murray]

The irradiance is based on historical data, which is from 06h00 to 18h30. The PF is fixed over this period, say 0.98 leading. I need to vary this signal by switching it on and off at any specific time during the period when active power is being produced, similar to an on/off timing device. The output of the PF block needs to be controlled.

[Walter Roberson]

What are the modeled consequences of turning it off?

What is the mathematics of turning it off? If, for example, you left it on for 4.5 hours, and turned it off for 0.5 hours, then what would be the mathematical effect?

How quickly can it be changed?

"The irradiance is based on historical data, which is from 06h00 to 18h30"

So... useless for real-world use, making this an academic exercise. If, at any point in the day, the decision to turn the signal on or off depends upon using the historical data as an oracle to predict how the rest of the day will definitely be, then this is all a "would'a-could'a" game.

It would be fair to use the historical data from before the modeled date as statistical, to model probabilities of what the rest of the day might be like -- but you risk failing to meet the target if the actual data does not match predictions.

Answer 1

[Dallas Perkins]

Hi Bill,

You could use a switch on your output line to change the value between what you have pictured and zero (or some other value). To switch the output at set times you could use something like a pulse generator or repeating sequence stair to specify those times.

https://www.mathworks.com/help/simulink/slref/switch.html

Best,

Dallas

[Bill Murray]

Hi Dallas,

Thank you for the advice. I used the switch on the output with a look-up table as one of the inputs to the switch.

Regards

Bill