T型三电平逆变器在不间断电源中的实现

针对两电平不间断电源（UPS）输出电压总谐波畸变率高的问题，本文设计的单相T型三电平不间断电源有效的降低了输出电压总谐波畸变率。首先根据开关频率和电压应力的要求，对T型三电平逆变器的开关器件和LC滤波器进行了硬件设计。然后，在开关函数模型中加入零电平电压，使逆变器输出三电平电压，有效的减少了输出电压中谐波的含量。最后，通过MATLAB/SIMULINK的仿真和6 kW不间断电源样机在阻性负载、非线性负载下的实验；得到了实验波形和0.23%的输出电压总谐波畸变率，结果验证了硬件设计的正确性，输出电压总谐波畸变率低于IEEE标准中5%的要求。

Implementation of T-type Three-level Inverter in Uninterruptible Power Supply

To resolve the high total harmonic distortion rate problem of output voltage in the two-level uninterruptible power supply， we designed a single-phase T-type three-level uninterruptible power supply. Firstly， we designed the switching device and LC filter for the T-type three-level inverter according to requirements of the switching frequency and voltage stress. Then， a zero-level voltage was added to the switching function， which made the inverter produce a three-level output voltage. Based on this method， the harmonic component in the output voltage can be reduced effectively. Finally， experiments were conducted based on MATLAB/SIMULINK as well as a 6 kW uninterruptible power supply prototype in the condition of resistive and nonlinear load， respectively. In experiments， we achieved waveforms and the total harmonic distortion rate was 0.23%. The results show that the hardware design is correct and the total harmonic distortion of output voltage is 5% lower than that of IEEE standard.