DC switching power supplies are widely used in industry
The technical indicators of DC power supply are divided into two kinds: one is the characteristic indicators, including the allowable input voltage, output voltage, output current and output voltage adjustment range, etc.; the other is the quality indicators, which are used to measure the degree of stability of the output DC voltage, including the voltage stabilization coefficient (or the voltage adjustment rate), the output resistance (or the current adjustment rate), and the ripple voltage (around and random drift).
DC switching power supply main circuit design
The main circuit of the DC switching power supply is used to complete the DC-AC-DC conversion, the main circuit of the system adopts a full-bridge DC-DC converter, the power switching device used in this system is the IGBT module of the BSM 50GB120DN2 series, and each module is a half-bridge structure, so that in the full-bridge system, two modules are required. Each module is embedded with a fast current-continuing diode.
DC switching power supplies have been widely used in many industrial fields. In industrial production (such as welding, electroplating or DC motor speed control, etc.), a large number of voltage-adjustable DC power supplies are required, and they generally require a DC power supply that can easily adjust the voltage output. At present, due to the switching power supply high efficiency, miniaturization and other advantages, the traditional linear regulated power supply, thyristor regulated power supply is gradually replaced by DC switching regulated power supply. The main control method of switching power supply is to use pulse width modulation integrated circuit to output PWM pulse, and use analog PID regulator to carry out pulse width modulation, this control method, there is a certain degree of error, and the circuit is relatively complex.
Working Principle
DC switching power supply consists of input part, power conversion part, output part and control part. The power conversion part is the core of the switching power supply, which carries out high-frequency chopping of non-stationary DC and completes the conversion function required for the output. It is mainly composed of switching transistors and high-frequency transformers. Figure 1 draws the schematic and equivalent block diagram of the DC switching power supply, which is composed of a full-wave rectifier, a switching tube V, an excitation signal, a current-renewal diode Vp, an energy storage inductor and a filtering capacitor C. In fact, the core part of the DC switching power supply is a DC transformer.
