I struggle to understand how can you switch positive or negative supply from a battery.
Firstly, what is a positive voltage and negative voltage?
I read many posts stating it all depends on your point of reference. To my understanding, current flows from negative to positive. Positive and negative current is just a difference in current flow.
The reason I am asking is I am in a process of studying Inverter Field control for Hybrid vehicles.
The booklet states:
By switching the positive or negative post of the battery to the three MG (Motor Generator) connections a current starts flowing through the MG's coils. The current through the MG coils creates a revolving or still magnetic field, making the rotor magnets in the MG's follow this field.
Please notice the current flow highlighted orange. I don't understand how can you switch positive or negative voltage and how does that affect anything. I also don't understand how can you have a positive voltage flowing in and the other end has negative voltage flowing out.
Moreover, how can 'give' or rectify negative voltage to the negative terminal a positive voltage to the positive terminal depicted below. What does that even mean?
I would appreciate an answer from an engineer explained in non-engineer terms. I know there are a lot of smart folks out there, but please keep it simple.