LOL. That is a bit of statist political sophistry. The question is not how many Senators constitute equal suffrage. The question is who gets to pick them. In article V the word "state" does not mean the demos of the state. It means the same thing that the word "state" means everywhere else in the constitution. It means the state legislatures.
Where did you read that suffrage means representation? It doesn't. Suffrage means the right to vote.
suffrage (ˈsʌfrɪdʒ) n
1. (Government, Politics & Diplomacy) the right to vote, esp in public elections; franchise
2. (Government, Politics & Diplomacy) the exercise of such a right; casting a vote
3. (Government, Politics & Diplomacy) a supporting vote
4. (Ecclesiastical Terms) a prayer, esp a short intercessory prayer
Equal suffrage, equal representation, equal voting, all mean the same thing in the Senate because the purpose of Senators is to vote on bills.
The 17th amendment didn't change the voting power of a state in the Senate because it didn't change the count of Senators for each state.
Changing the way a Senator is selected may change how the state's delegation votes on a particular bill, but it doesn't change the equal voting power of a state in the Senate.
-PJ