一种新型拓扑的三电平变换器及其损耗分析

A new topology of three-level converter and analysis of losses calculation

针对传统Vienna型整流器无法实现逆变工作的缺点,提出一种新型拓扑结构的三电平变换器,该变换器可工作于双向变换状态。为了降低新型拓扑三电平变换器的功率损耗,采用断续脉宽调制(discontinuous pulse width modulation,DPWM)策略中综合性能较优的共模电压最小DPWM策略(discontinuous pulse width modulation scheme A,DPWMA)进行调制。在此基础上,根据新型拓扑在DPWMA策略下功率器件的开关规律,建立了其在并网逆变器工况下的功率损耗计算模型。仿真和实验结果验证了新型拓扑和损耗模型的正确性,以及采用DPWMA在减少开关器件功率损耗方面的有效性。

Aiming at the shortcomings that traditional Vienna rectifiers can't work as inverters,a new topology of converters is proposed,which can work in both the rectifier state and the inverter state.In order to decrease the power losses of the new typology three-level converter,the DPWMA strategy which has better comprehensive performance among DPWM strategy is adopted for modulation,and the strategy is realized by the way of CBPWM.Then the power loss calculation model at inverter operating mode is established based on the mechanism of the switching law of power devices under the new topology in DPWMA.The characters of the new topology and correctness of the model and the effectiveness of DPWMA on reducing the power loss of switches are demonstrated by simulation and experiments.