Classification and characteristics of AC power supply and AC voltage stabilizing power supply
A power supply that can provide a stable voltage and frequency is called an AC stable power supply. At present, most domestic manufacturers work on stabilizing AC voltage. Below is a brief description of the classification characteristics of AC stabilized power supplies available in the market.
The basic principle of voltage stabilization for parameter adjustment (resonance) type power supplies is LC series resonance. The early emergence of magnetic saturation type voltage regulators belongs to this category. Its advantages are: simple structure, no numerous components, high reliability, wide voltage stabilization range, strong anti-interference and overload resistance. The disadvantages are: high energy consumption, high noise, bulkiness, and high cost. The parameter voltage regulator developed based on the principle of magnetic saturation and the popular "magnetic amplifier adjustable electronic AC voltage regulator" (i.e. 614 type) in China in the 1950s both belong to this type of AC voltage regulator.
Autocoupling (ratio) adjustment type 1, mechanical voltage regulation type, which uses a servo motor to drive the carbon brush to move on the sliding surface of the winding of the autotransformer, changing the ratio of Vo to Vi to achieve output voltage adjustment and stability. This type of voltage regulator can range from several hundred watts to several thousand watts. Its characteristics are simple structure, low cost, and low output waveform distortion; However, due to the easy generation of electric sparks at the sliding contact of the carbon brush, the brush may be damaged or even burned out, resulting in failure; And the voltage adjustment speed is slow. 2. Change the tap type, make the autotransformer into multiple fixed taps, and use relays or thyristors (solid-state relays) as 10 switches to automatically change the tap position, thereby achieving stable output voltage. The advantages of this type of voltage regulator are simple circuit, wide voltage range (130V-280V), high efficiency (≥ 95 [%]), and low price. The disadvantage is that the voltage stabilization accuracy is low (± 8-10 [%]) and the working life is short. It is suitable for supplying power to air conditioners in households.
High power compensation type - purification type voltage regulator (including precision type voltage regulator) uses a compensation link to achieve stable output voltage, making it easy to achieve microcomputer control. Its advantages are good anti-interference performance, high voltage regulation accuracy (≤ ± 1 [%]), fast response (40-60ms), simple circuit, and reliable operation. The disadvantage is that there is low-frequency oscillation when carrying non-linear loads such as computers and programmable switches; The input current distortion is high, and the source power factor is low; The output voltage has a phase shift compared to the input voltage. Units with high requirements for anti-interference function are suitable for application in cities. When supplying power to computers, a voltage regulator that is about 2-3 times the total power of the computer must be selected for use. Due to its advantages of stable voltage, anti-interference, fast response speed, and moderate price, it is widely used.
The switch type AC stabilized power supply is applied in high-frequency pulse width modulation technology. The difference from general switch power supplies is that its output must be an AC voltage of the same frequency and phase as the input side. Its output voltage waveform includes quasi square wave, ladder wave, sine wave, etc. When the uninterruptible power supply (UpS) on the market removes its storage power and charger, it becomes a switch type AC stabilized power supply with good voltage stability, strong control function, and easy to achieve intelligence. It is a very promising AC stabilized power supply. But due to its complex circuit and high price, promotion is slow.
