Direct Current and Alternating Current Regulated Power Supplies
An electronic device that can provide stable AC or DC power to a load. It includes two categories: AC stabilized power supply and DC stabilized power supply.
AC voltage stabilizer power supply, also known as AC voltage stabilizer. With the development of electronic technology, especially the application of electronic computer technology in various industrial and scientific research fields, various electronic devices require stable AC power supply. Direct power supply from the power grid can no longer meet the needs. The emergence of AC stabilized power supply has solved this problem. The commonly used AC voltage regulators include:
① ferromagnetic resonance AC voltage regulator. Composed of a saturated choke and corresponding capacitors, it has constant voltage volt ampere characteristics.
② Magnetic amplifier type AC voltage regulator. Connect the magnetic amplifier and autotransformer in series, and use electronic circuits to change the impedance of the magnetic amplifier to stabilize the output voltage.
③ Sliding AC voltage stabilizer. Stabilize the output voltage by changing the sliding contact position 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 can be stabilized.
⑤ Thyristor AC voltage regulator. Use thyristors as power adjustment components. High stability, fast response, and no noise. But it causes interference to communication and electronic devices. After the 1980s, three new types of AC voltage regulators emerged: compensating AC voltage regulators. Numerical control and stepper AC voltage regulators. Purified AC voltage regulator. It has good isolation function and can eliminate peak interference from the power grid.
DC stabilized power supply, also known as DC stabilizer. Its power supply is mostly AC power, and when the voltage or load resistance of the AC power supply changes, the direct output voltage of the voltage regulator can remain stable. The parameters of a voltage regulator include voltage stability, ripple factor, and response speed. The former represents the impact of changes in input voltage on output voltage. Ripple coefficient represents the magnitude of the AC component in the output voltage under rated operating conditions; The latter represents the time required for the voltage to return to normal when there is a sudden change in input voltage or load. DC stabilized power supplies are divided into two types: continuous conductive and switch mode. The former uses a transformer to convert single-phase or three-phase AC voltage to an appropriate value, and then rectifies and filters it to obtain an unstable DC power supply, which is then stabilized by a voltage regulator circuit to obtain a stable voltage (or current). This type of power supply circuit is simple, with low ripple and minimal mutual interference, but it has a large volume, consumes a lot of materials, and has low efficiency (often below 40% to 60%). The latter adjusts the output voltage by changing the on-off time ratio of the adjusting component (or switch) to achieve voltage stabilization. This type of power supply has low power consumption and an efficiency of about 85%. So, it has developed rapidly since the 1980s. From the working mode, it can be divided into: ① Controllable rectification type. Adjust the output voltage by changing the conduction time of the thyristor. ② Chopping type. The input is an unstable DC voltage, which is obtained by changing the on-off ratio of the switch circuit to obtain unidirectional pulsating DC, and then filtered to obtain a stable DC voltage. ③ Transformer type. Unstable DC voltage is first converted into high-frequency AC power by an inverter, and then transformed, rectified, and filtered. The resulting new DC output voltage is sampled and feedback controlled to regulate the inverter's operating frequency, achieving the goal of stable output DC voltage.
