Switched-mode power supplies utilize electronic switching devices (such as transistors, field-effect transistors, and thyristor SCR's, etc.) to control the devices by switching them on and off continuously. This process allows the devices to pulse-modulate the input voltage, thereby achieving DC/AC and DC/DC voltage conversions, as well as adjustable output voltage and automatic voltage regulation. A switched-mode power supply is generally composed of four main parts: the main circuit, the switching power supply control circuit, the detection circuit, and the auxiliary power supply.
1. Main Circuit
Clamping surge current: Limiting the surge current on the input side during the moment of power connection.
Input Filter: Its function is to filter out noise from the power grid and prevent the noise generated by the equipment from feeding back into the grid.
Rectification and Filtering: Directly converts AC power from the power grid into a smoother DC current.
Inversion: Converts rectified DC electricity into high-frequency AC power, which is the core component of a high-frequency switching power supply.
Regulated and Filtered Output: Providing stable and reliable DC power according to load requirements. Aviation Ground Power 2, 36V Aviation Power 1, 400Hz Variable Frequency Power Supply 7, 115/200V Power Supply 2, 27V DC Power Supply 5, 400Hz Power Supply 12, Aviation Power
2. Control Circuit
On one hand, sampling from the output end and comparing it to the set value, then controlling the inverter to alter its pulse width or frequency to stabilize the output. On the other hand, based on the data provided by the test circuit and differentiated by the protective circuit, various protective measures for the power supply are provided to the control circuit.
3. Circuit Testing
Provide protection circuit with real-time parameters and instrument data.
4. Auxiliary Power Supply
Software (remote) startup of power supply, providing power for circuit protection and control circuits (PWM chips, etc.). Key Advantages: Small size, light weight, high efficiency, suitable for high power ratings. (Ideal for high power rating and high power consumption applications). Major Disadvantages: Poor voltage regulation coefficient, high-frequency interference, and large output ripple. (Not suitable for applications with high ripple requirements and where high-frequency interference needs to be considered).
