Transformer switch energy storage

What is a power transformer in switch-mode power supplies?

The purpose of a power transformer in Switch-Mode Power Supplies is to transfer power efficiently and instantaneously from an external electrical source to an external load. In doing so, the transformer also provides important additional capabilities:

Do Transformers store energy?

Separate primary and secondary windings facili-tate high voltage input/output isolation, especially important for safety in off-line applications. Ideally, a transformer stores no energy–all energy is transferred instantaneously from input to output. In practice, all transformers do store some undesired energy:

How do transformer losses affect power supply efficiency?

Transformer loss is sometimes limited directly by the need to achieve a required overall power supply efficiency. More often, transformer losses are limited by a maximum “hot spot” temperature rise at the core surface inside the center of the windings. Tempera-ture rise (°C) equals thermal resistance (°C/Watt) times power loss (Watts).

What is a multi-winding transformer-based cell equalizer?

This work introduces a new multi-winding transformer-based cell equalizer with self-driven switches series-connected energy storage cells. With the equalizer, all series-connected cells can be equalized in both charging and discharging manners, towards the same balance voltage.

What are transformer-based topologies?

As for the transformer-based topologies, each cell of the battery string is usually coupled by the magnetic core so that the energy can be exchanged between arbitrary cells. In , a bidirectional-flyback converter using transformers was proposed.

What is a self-driven switch based on a multi-winding transformer?

Self-driven switches based on a multi-winding transformer greatly reduce the balancing circuit complexity and cost. The equalizer is controlled by a pair of complementary square-wave signals rather than complex control balancing algorithm. There is no significant conduction loss, since MOSFETs are used as switches rather than diodes.