Research On A New Type Of Three-level Inverter Based On TMS320F2812

With the rapid development of modern power electronic technology and digital control technique, the converter has been used in more and more fields, especially in the applications of high power, the three-level converters are widely used.With respect to the traditional two-level inverter, three-level inverter has the characteristics of the output of the low harmonic content, the low switching frequency and the low electric stress of power device etc.This paper introduces the topology in the present three-level inverter, it focuses on the analysis of the working of diode clamped three-level inverter. On this basis, this paper picks up a new topology of the three-level inverter, and the topology is analyzed in detail. This new topology dose not need clamping diodes and can keep the balance in the switching loss, also it can simplify the design of drive and reduce the number of drive power. Meanwhile, compare with the traditional three-level SVPWM algorithm and the two-level SVPWM algorithm, we put forward a simple three-level SVPWM algorithm. This algorithm, using the geometric relations of space vector diagram of two level and three-level space vector diagram, Cleverly converts basic linear vector action time of two-level SVPWM algorithm to the three-level SVPWM algorithm. It avoids the operation of trigonometric function, greatly reduces the amount of calculation and easily realizes the digitization. Afterwards, this paper Introduces the three-level inverter PWM waveform, and puts forward to the PWM by the first way of redundant small vectors. This method can avoid the conflict of vector transformation in different sectors when switching and can effectively reduce the switching loss. Finally, according to the three-level inverter, the neutral point potential including the new topology of the three-level inverter has the imbalance problem, this paper proposed a controlling mean by changing the redundancy vector time of neutral point potential.In the MTALAB/simulink, the new topology, the proposed algorithm and the midpoint control simulation are simulated, the results demonstrate the validity and effectiveness of the proposed topology and method.On this basis, it has the independent design and builds the hardware circuit, Including the minimum system of TMS320F2812, drive circuit, the midpoint potential detection circuit, and the main circuit and power design of the whole system in the diode clamped three-level inverter and the three-level inverter of new topology structure. In the hardware platform the simplified three-level SVPWM is achieved. The experimental results show that, the three-level inverter of new topology structure and the simplified three-level SVPWM algorithm can make all the three-level inverter inverter. Also, it confirms the correctness and validity of the topology and theory what is said above.