Widely used in industry, DC switching power supplies
The technical indicators of DC power supply are divided into two kinds: one is characteristic indicators, including allowable input voltage, output voltage, output current and output voltage adjustment range, etc.; the other is quality indicators, which are used to measure the degree of stability of the output DC voltage, including the voltage regulator factor (or voltage adjustment rate), the output resistance (or 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 conversion of DC-AC-DC, and the main circuit of the system uses a full-bridge DC-DC converter. The power switching devices used in this system are BSM 50GB120DN2 series IGBT modules, each module is a half-bridge structure, so in the full-bridge system, two modules are needed. Each module is embedded with a fast current-continuing diode.
DC switching power supplies have been widely used in many industrial applications. In industrial production (such as welding, electroplating or DC motor speed control, etc.), a large number of voltage adjustable DC power supply is required, they generally require a DC power supply that can easily adjust the voltage output. At present, due to the high efficiency of switching power supply, miniaturisation 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 analogue PID regulator for 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.
