Dsp-based Power Inverter Design Study

With development of the science technology, the application of the inverter power supply is becoming more and more widely in our society. And at the same time, a higher technical demanding of the inverter is proposed for the green energy recent years, which leads to the development trend to a high frequency, high efficiency and high performance of the inverter, followed by the increasing demanding of the performance of the controller chip, power converter and the control system. The research and implementation of a high-frequency band DC-link inverter chain based on the TMS320F2802 DSP controller chip are proposed in this thesis.First, the design of the main circuits of the inverter with DC link is analyzed in this paper. And the ZVS soft-switching technology is applied to reduce the switching loss and the EMI of the former DC-DC inverter. The principle and working conditions of the push-pull topology DC-DC boost converter circuits using ZVS soft-switching technology are analyzed in detail, so are the full-bridge DC-AC inverter circuits and the modulation of the SPWM of the later circuits.Then the mathematical model of the inverter is established, using the uncertainty and nonlinearity of the external load as its current source disturbance. The performance of the strategies of the voltage feedback control, current feedback control and voltage & current double closed-loop feedback control using the root-locus method are analyzed in detail based on this mathematical model. According to the real situation of the inverter, the dual loop feed-forward PI control is proposed to eliminate the bad characteristic influence of output caused by the changing DC input voltage. And the specific controller parameters of the inverter are rationally chosen according to the requirements of the control system.Both the hardware and the software systems of the inverter based on TMS320F2802 DSP are described in this thesis. Using the enhanced PWM module for the control of MOSFET in the TMS320F2802, the hardware of the main topology circuits, sampling feedback circuits, auxiliary circuits, protection circuits and feedback circuits are designed. And the software modules of the soft switching, signal sampling, double-loop control, SPWM waveform generation, abnormal shutdown and other function modules are programmed for the inverter.