An electronic power supply known as a switched-mode power supply (SMPS) includes a switching regulator to effectively convert electrical power. Because the transformer may be far smaller, switched-mode power supplies can also be significantly lighter and smaller than a linear supply. This is because, in contrast to the 50 or 60 Hz mains frequency, it operates on a high switching frequency that ranges from several hundred kHz to several MHz. Despite the smaller transformer, commercial designs often have a substantially higher component count and accompanying circuit complexity due to the power supply architecture and the need to control electromagnetic interference (EMI).
Benefits and Features of Switching Converter, SMPS Transformers
- Because the switching transistor uses less power when serving as a switch, the switching power supply has better efficiency (up to 96 percent) than linear regulators.
- Other benefits include equivalent heat generation, smaller size, lesser noise, and lighter weight due to the absence of bulky line-frequency transformers.
- Transformers often have a substantially higher standby power loss. A switching power supply uses a smaller transformer than a conventional line frequency (50 Hz or 60 Hz, depending on area) transformer, which saves money on raw materials like copper.
Transformer Design
Transformers are necessary for galvanic isolation in any switched-mode power supply that draws electricity from an AC power line. Transformers or switching converter smps transformers are sometimes used in DC-to-DC converters, albeit isolation may not be necessary for some situations. Transformers used in SMPS operate at high frequency. The reduced size of the high-frequency transformer compared to the 50/60 Hz transformers previously utilized is what accounts for most of the cost reductions in the off-line power supply. Additional design compromises exist.
The ratio of a transformer's core size, magnetic flux, and frequency to its product determines its terminal voltage. The core area, and thus the core's mass, may be significantly lowered by employing a considerably higher frequency. Higher frequencies, however, result in greater core losses. Ferrite material, which has a low loss at the high frequencies and high flux densities utilized, is typically used in cores. At switching frequencies of a few kilohertz, the laminated iron cores of lower-frequency (400 Hz) transformers would exhibit unacceptable loss. Additionally, at higher frequencies, the switching semiconductor loses more energy during transitions.
Types
Circuit topology may be used to categorize switched-mode power supply. The key contrast is between isolated and non-isolated converters.
- Non-isolated Topologies: The three fundamental forms of non-isolated converters each use a single inductor to store energy, making them the simplest. The duty cycle of the converter, shown by D in the voltage relation column, ranges from 0 to 1. The output voltage should be negated if the input voltage (V1) is negative to maintain consistency (V2).
- Isolated Topologies: By varying the turns ratio, any isolated topology with a transformer can create an output with a voltage that is greater or lower than the input. In some topologies, the transformer might have numerous windings installed on it to create different output voltages. [40] Some converters store energy in the transformer, while others employ an additional inductor.
