H桥多电平逆变器的混合载波交叠式PWM控制

The hybrid carrier overlap PWM control of H bridge multilevel inverter

为了增大逆变器的功率等级,改善输出电压的波形质量,提出了一种级联H桥多电平逆变器拓扑和与其相对应的PWM载波调制控制策略。该方法是根据传统混合频率载波调制策略,采用了同相的交叠式三角载波调制,结合了同相层叠式载波调制较好的消谐特点以及使高低压单元功率自然平衡的特点,使级联H桥多电平逆变器拓扑结构不仅可以输出多电平,还能解决混合调制下的功率环流现象,而且逆变器模块化比较简单,可以使逆变器在输出周期内功率达到自然平衡。以2个高低压单元为例,进行了仿真实验。实验结果验证了该逆变器结构和控制策略的可行性。

In order to improve the power level of inverter,and improve the waveform quality of the output voltage,the topological and corresponding PWM carrier modulation control strategy of cascade H bridge multilevel inverter is proposed in this paper. According to the traditional mixed frequency carrier modulation principle,this method adopted in phase overlap triangle carrier modulation,with a combination of good harmonic elimination characteristics of the in-phase cascading triangular carrier modulation and the advantages of each unit power natural equilibrium,the cascade multilevel inverter topology H bridge not only can output the multilevel structure,avoid mixed modulation power circulation problems,and the modular inverter is simpler,which can be implemented in an output cycle power balance. Taking two high and low pressure units as an example,the simulation experiment was carried out. The experimental results verify the feasibility of the inverter topology and its control strategy.