The composition and function of low-power semiconductor DC stabilized power supply system
The commonly used low-power semiconductor DC stabilized power supply system consists of four parts: power transformer, rectifier circuit, filter circuit and voltage stabilizer circuit. Figure 9-1 shows its principle block diagram and output waveforms of each part.
The functions and functions of the components of the DC regulated power supply:
(1) Power transformer: Provide the AC voltage of the required value for the electrical equipment. The AC voltage provided by the grid is generally 220v (or 380v), and the secondary coil voltage u2 is low, which can reduce the withstand voltage requirements for the components used in the rectification, filtering and voltage stabilization circuits, so it is necessary to use a transformer to convert the grid voltage into all The alternating voltage of the desired value.
(2) Rectifier circuit: convert alternating current into direct current. Using components with unidirectional conductivity (such as diodes and thyristors), the alternating positive and negative sinusoidal AC voltage u2 output by the transformer is rectified and transformed into a unidirectional pulsating DC voltage D3.
(3) Filter circuit: Convert the rectified direct current with large pulsation into smooth direct current. Usually, energy storage elements such as capacitors and inductors are used to filter out the harmonic components in the unidirectional pulsating voltage u3.
(4) Voltage stabilization circuit: Overcome the change of output voltage caused by the change of grid voltage or load current, and maintain the stability of output voltage.
