Design Of Parameter Self-tuning Method For PI Controller In DC-AC Conversion

Nowadays,DC-AC converter is widely used in the fields of industry,home electronics,ship and aerospace.With the continuous expansion of its application range,the requirements for the speed and accuracy of the output response of the converter and the adaptability when the load changes are higher and higher.Therefore,the reasonable control strategy is selected to ensure the accuracy and stability of the converter output,and has good dynamic performance Performance has become the focus of current research.The PI control strategy,which is widely used nowadays,is characterized by its simple algorithm and easy implementation.Although it can make the system have good steady-state performance,it can not meet the requirements of fast and accurate,under the condition of sudden change of input voltage and load.In this paper,a novel parameter tuning strategy of DC-AC converter based on energy balance is proposed.Firstly,the main circuit topology of DC-AC converter is designed,and two commonly used modulation technologies,sinusoidal pulse width modulation(SPWM)and space voltage vector pulse width modulation(SVPWM),are selected to design the traditional double closed loop fixed parameter PI control system with three-phase voltage source full bridge inverter circuit as the research object.The two modulation methods are analyzed in principle,and then a three-phase DC-AC conversion simulation system with fixed parameter PI controller is built in Matlab / Simulink,and the start-up process and dynamic process are simulated and verified.Then,the paper analyzes the energy flow process among the input energy,the change of energy storage capacity of inductors and capacitors and the energy consumed by the load during the operation of the DC-AC converter system,and calculates the energy transfer coefficient.On this basis,a control strategy is designed to regulate the parameters of a controller through the difference between the desired energy and the actual energy and the variation of the energy difference,simplifying the segmentation function,reduces the number of control rules and facilitates the implementation of the control strategy.The performance of the controller is compared with that of the traditional controller Pi in terms of performance and feasibility.Finally,the hardware experimental platform of DC-AC converter parameter self-tuning control system is built.An experimental circuit was developed,including the main circuit,the drive-protected circuit,voltage detection and current detection.Under CCS conditions,the DSP programs necessary for the experiment were developed,and based on the energy balance,the hardware experiment for the self-regulation systems was completed.confirmed the viability and correctness of the management system.