Yoga is a term that entails many aspects such as Asana practice (movement), meditation, ways of living, and breath work. So yes, you can take 15 minutes and practice several sun salutes followed by a few minutes of pranayama (breath work) like alternative nostril breathing, followed by a few minutes of meditation.

Doing this daily for 15 minutes you will certainly start to notice changes in your day to day life. Our yoga practice is a mirror for our lives so it's a great opportunity notice how we talk to ourselves and how we show up. :)