How does the dw switch store energy

Does switching consume power?

Of course there is also the energy needed to "throw" the switch, in the form of gate charge/discharge. Switching results in current such that a voltage changes. Resistance is never zero, so until we have superconducting ICs, switching always consumes power (= I^2*R).

How does a DC-DC converter work?

DC-DC converters like forward converters, push-pull converters, half-bridge converters, and full-bridge converters—all of which use the on-on method—transfer energy from input to output side through a transformer when activated. Since the excitation energy required is small, no gap in the transformer is necessary.

How is energy stored in an inductor?

The energy in an inductor is stored in the magnetic field which is generated by the current passing through the inductor. In terms of how the energy gets there you need to think of the inductor having no current passing through it at the start and then applying a voltage source across the inductor.

Does pulling up and down at the same time waste energy?

Yes, that's a good point. There is waste when you pull up and down at the same time. Simple answer, and not too accurate. Transistors need continuous current in their base to remain ON, so they consume energy while they are in ON state. When you turn them off, they simply stop to consume energy.

What is the switching function in inverters?

The switching function in inverters is needed to alternate the direction of the DC current in order to produce AC power. This is typically performed using electronic semiconductor devices like transistors and thyristors. Thyristors are commonly used in basic models of inverters.

How does a gate switch from 'off' to 'on' state?

In order to switch from "off" to "on" state, its gate needs to be charged to a suitable voltage, which involves both gate-source and gate-drain capacitance. The charge required is called "gate charge". The current to charge it comes from the driving circuitry, which has to expend a bit of energy to provide it.