Introduction to Switching Power Supply and Phase Control Power Supply
1. Linear regulated power supply can meet the requirements of high and low DC voltage required by electronic circuits and power supply quality (accuracy, ripple, etc.), but there are two major drawbacks: firstly, adjusting the VT transistor to work in a linear amplification state, resulting in high losses and low power efficiency; The second is to use a power frequency transformer T to make the entire power supply bulky and heavy.
2. Switching power supplies are designed to overcome the drawbacks of linear regulated power supplies, named after their power (power) electronic devices that always operate in a switched state.
3. Phase controlled power supply is the abbreviation of thyristor phase controlled power supply. Similar to switching power supplies, the power electronic devices in phase controlled power supplies also operate in a switching state, but their operating frequency is power frequency (50Hz), not high frequency. In contrast, a significant advantage of phase controlled power supply is its simple circuit and convenient control. Its main drawback is also the need for a power frequency transformer, which makes the entire power supply bulky and heavy. In addition, the ripple frequency of the DC output voltage of the phase-controlled power supply is only a few times the power frequency (2 times for single-phase full bridge control and 6 times for three-phase full bridge control), and a larger filter is required to have a good filtering effect. The DC output voltage ripple frequency of the switching power supply is very high, often above 20kHz, so only a very small filter is needed. Due to the low switching frequency of the phase controlled power supply, its response speed to control is also slower than that of the switching power supply.
According to convention, a switching power supply specifically refers to a DC power supply in which power (power) electronic devices operate in a high-frequency switching state, hence it is also called a high-frequency switching power supply, while a phase controlled power supply is not included in the switching power supply.
