Research On Digital Control Technique For Single-phase Inverters

With the development of modern technology, more and more inverter powers are applied in our livers. Good output waveform of inverter mainly includes three aspects:high steady-state precision, good dynamic performance and good load adaptability. The digital control method of using repeat control plus pole configuration is adapted to improve the steady-state and dynamic performance, and to meet the high performance requirements of the inverter.Firstly, established the mathematical model of Single-phase full bridge inverter, and the influence of the parameters to the inverter is discussed in this paper. The sinusoidal pulse width and SPWM wave generating method are introduced, explaining why the Single-phase inverter waveform distortion.Secondly, The basic idea of repetitive control is clarified, and the stability and steady-state error of the control system are discussed. The single full-bridge inverter is adopted. The controller is designed to eliminate the inverter’s resonant peak by notch filter and compensate for the phase deviation using time advanced link.The state feedback is carried on the pole assignment due to the low response speed of the repetitive controller’s dynamic. With the pole assignment controller in the inner ring and the repetitive controller in the outer ring, simulation model of the inverter system is established by the simulation, environment of Matlab/Simulink, the simulation results show that, the composite digital control strategy to achieve the desired steady-state and dynamic performance.Then, the hardware structure of the system is described, including the design of the main circuit, the inverter’s drive circuit, sampling circuit, power supply of system, the JTAG interface, the protection circuit and the CAN bus interface. System interference is also analyzed and anti-interference measure taken in the system is introduced.Finally, explaining the software design of the inverter system. Then introduces the development environment-CodeWarrior IDE. Introduces the main program flow char and gives some flow charts. Based on the DSP (MC56F8346) complete the single-phase inverter experiment, the results show that the digital control strategies greatly improving the inverter’s dynamic and static performance.