What components of a DRAM (specifically LPDDR) memory do the power rails VDD1, VDD2 and VDDQ supply the power to?
To analyze the power consumed by the DDR3 die in different rails in different operating modes, you can use micron ddr3 power calculator xls. Here all you need to enter your requirement, such as

DRAM Density
Number of DQs per DRAM
Speed grade
DDR3 or DDR3L
Mode register bit
DDR3 memory controller
DDR3 die clock frequency

Power calculator xls throws you the exact power based on Data sheet test conditions and maximum limits, Power derated for system usage condition input and Total DRAM power consumed.
Also power consumption for different operating modes such as active, idle, self-refresh, deep-power-down mode appears immediately after entering your requirement.
This power calculation xls can be used for any vendor DDR3 die because all the DDR3 vendor follows JEDEC standard.

Hope this helps