Hi
You have to stay in Canada for 2 years in a period of 5 years to renew your PR.
Before getting down to your issue, to clarify the right thing to do is to reapply for immigration in 2017, however let me just assure you that if you are already inside Canada even with 100 days left on your PR card expiry, you will not be kicked out of the country. You need to complete your 2 years inside Canada (with an expired PR) and than apply for PR renewal after 2 years are over. During this period you may not leave Canada for a single day (especially after the expiry date of the PR card).
Now from what I understand about your case; since you became a PR on Feb 1, 2013, your 5 year period ends on Jan 31, 2018. so if you move in September 2017, you will only have 4 months left (how did you calculate 550 days?) to complete your residency requirement. Now comes the real challenge, entering the country in Sept 2017. The immigration officer in Canada, may notice this and he can choose to report you to CIC, that you will not be able to fulfill your residency requirement. Once this investigation starts the outcome is unpredictable and depends on who gets your case. On the other hand the immigration officer might not notice this and just stamp your passport and say welcome back
To put yourself in good standing in Sept 2017, I can suggest (my opinion only) you do the following:
1. Buy some property in Canada (but only if you can afford it).
2. Declare your foreign income every year in your income tax return and pay at least a nominal tax amount in Canada.
3. Spend your vacations in Canada, perhaps leaving the family longer if you need to return home quickly due to job.
Hope this helps
Regards,