Low Power Unidirectional Voltage Source High-frequency Link Inverter

This dissertation emphasizes on one type inverter which is commonly used in areas such as UPS and new energy sources. This kind of inverter has the characteristics such as low input voltage, high current and sine wave output with low frequency. After analysis on the topologies and control strategies of high-frequency link inverter, push-pull circuit is fixed as the main topology structure and the control circuit based on TMS320F2812 is also designed.The overall strategy about the inverter is DC-DC-AC. The strategy has two power conversion levels. In the first level, the two power switches are modulated by SPWM pulses by which input voltage is chopped into SPWM. The pulses are boosted by high frequency transformer, rectified by the two diodes. The unidirectional high voltage SPWM pulses are backward at each half cycle and standard sine wave is got by low pass filter. Level 1 is an independent system. To achieve better dynamic and static characteristics closed-loop control is preferred. The dissertation uses multi-loop feedback control such as instantaneous, RMS voltage and instantaneous current of filter capacitor to control the inverter.The drive signals for push-pull circuit and backward circuit are produced by the DSP processor and it also monitors the entire control system all the time.Finally, the push-pull unidirectional voltage source high-frequency link inverter is simulated in MATLAB6.5/Simulink. The result shows its feasibility. The device of the inverter system is completed by the TMS320F2812 evaluation board and ICETEK-5100USBV2.0A simulator. Part of the experiment is carried out and the results are also presented.