DC regulated power supply and AC regulated power supply
AC regulated power supply is also called AC voltage stabilizer. With the development of electronic technology, especially after the application of electronic computer technology to various industries and scientific research fields, all kinds of electronic equipment require a stable AC power supply, and the direct power supply of the grid can no longer meet the needs. a question.
Commonly used AC regulated power supplies are:
①Ferromagnetic resonance AC voltage regulator. Composed of saturated choke coils and corresponding capacitors, it has constant voltage and voltage characteristics.
②Magnetic amplifier type AC voltage stabilizer. The magnetic amplifier and the autotransformer are connected in series, and the electronic circuit is used to change the impedance of the magnetic amplifier to stabilize the output voltage.
③Sliding AC voltage stabilizer. The output voltage is stabilized by changing the position of the sliding contact of the transformer.
④ Inductive AC voltage regulator. By changing the phase difference between the secondary and primary voltages of the transformer, the output AC voltage is stabilized.
⑤Thyristor AC voltage regulator. Thyristors are used as power adjustment components. High stability, fast response and no noise. However, it may cause interference to communication equipment and electronic equipment.
After the 1980s, three new types of AC stabilized voltage sources appeared: compensated AC voltage stabilizer. Numerically controlled and stepping AC voltage regulators. Purified AC voltage stabilizer. It has a good isolation effect and can eliminate the spike interference from the power grid.
DC stabilized power supply is also called DC voltage stabilizer. Its power supply is mostly AC power supply, when the voltage of the AC power supply or the load resistance changes, the direct output voltage of the regulator can remain stable.
The parameters of the voltage regulator include voltage stability, ripple coefficient and response speed. The former represents the impact of changes in the input voltage on the output voltage. The ripple coefficient indicates the magnitude of the AC component in the output voltage under rated operating conditions; the latter indicates the time required for the voltage to return to the normal value when the input voltage or load changes sharply. DC regulated power supply is divided into two types: continuous conduction type and switching type. The former uses a transformer to change the single-phase or three-phase AC voltage to an appropriate value, then rectifies and filters it to obtain an unstable DC power supply, and then obtains a stable voltage (or current) through a voltage stabilizing circuit. This kind of power supply has simple lines, small ripples, and low mutual interference, but it has large volume, many consumables, and low efficiency (often lower than 40% to 60%). The latter adjusts the output voltage by changing the on-off time ratio of the adjustment element (or switch), so as to achieve voltage regulation. This type of power consumption is small, and the efficiency can reach about 85%. Therefore, it has developed rapidly since the 1980s.
From the working method can be divided into:
①Controllable rectification type. The output voltage is adjusted by changing the conduction time of the thyristor.
② chopping type. The input is an unstable DC voltage, and the one-way pulsating DC is obtained by changing the on-off ratio of the switch circuit, and then a stable DC voltage is obtained after filtering.
③ Converter type. The unstable DC voltage is first transformed into high-frequency AC by the inverter, and then transformed, rectified, and filtered, and the new DC output voltage is sampled, and the operating frequency of the inverter is feedback controlled to achieve the purpose of stabilizing the output DC voltage.
