emulator

I am trying to build a circuit to emulate a lipo battery. Basically the circuit consists in a power supply to emulate the discharge behaviour and a variable load to eulate the charge behaviour. This is the circuit in a simplified way This basically generates 2 circuits...

I am new to the embedded development area and doing self-study in this area (I am already from Computer Science background) but I have few doubts and need guidance on the development and testing tools used in this area. Q1. What is the difference between :- openOCD, pyOCD, Segger J-Link...