Overview of Model free Control for Switching Power Supply
With the rapid development of power electronics technology, the relationship between power electronic devices and people's work and life is becoming increasingly close, and electronic devices cannot do without reliable power sources. Switching power supply is a type of power supply that utilizes modern power electronics technology to control the time ratio of switching transistors on and off, and maintain a stable output voltage. Switching power supply is generally composed of pulse width modulation (pWM) control IC and MOSFET. The control part of switch mode power supply is mostly designed and operated based on analog signals, but the disadvantage is poor anti-interference ability. Due to the rapid development of computer control technology, the processing and control of digital signals have shown obvious advantages: easy computer processing and control, greatly improved design flexibility, and convenient software debugging, resulting in the emergence of pID control.
The lack of model control in switching power supplies has led to the development of digital, intelligent, and multifunctional switching power supplies. This undoubtedly improves the performance and reliability of switch mode power supplies. However, due to the fact that switch mode power supplies are inherently nonlinear objects, it is quite difficult to establish an accurate model, which is often approximated. Moreover, their power supply system and load changes are uncertain. Therefore, using the above analog or digital PID control methods often makes it difficult to change the parameters of the PID controller accordingly, and the control effect is not ideal. The recently developed model free control is a promising control method. It does not rely on the mathematical model of the controlled object, integrates modeling and control, which is very suitable for some complex and variable or structurally uncertain systems that are difficult to describe with accurate mathematical models. It improves the control system of switching power supplies, not only meeting the requirements of high performance and high reliability of switching power supplies.
