Chronitons reset at a rate of one every six minutes and can be fully recharged for 150 Dilithium up to twice per day.
As you increase your VIP level, the amount of recharges you can purchase per day goes up by one per VIP level. The recharge rate of one per six minutes remains the same regardless of VIP level.
A Chroniton Recharge is not the same as a Chroniton Boost, which becomes available several times a day during specific hours for all players. There is no way to increase the number of Chroniton Boosts that you could take advantage of in a day.