Inorganic ions are indispensable substances in living systems, which have been widely involved in many essential biological processes. Increasing evidences have shown that the disruption of ion homeostasis is closely...

Neutral point voltage balancing is an inherent problem of three-level rectifier. This paper first analyzed the cause to the neutral point voltage deviation of the DC-side three-level rectifier, and studied the charge and discharge transient processes of the two DC-side capacitors and the harmonic characteristics of the current of the AC-side rectifier respectively when the carrier ratio is an odd number or even number. It also verified its studies through simulation. The results showed that, when the carrier ratio is an even number, the neutral point voltage of the three-level rectifier is more easily to be balanced and will not cause bad influence on the harmonic characteristics of the AC-side rectifier. Topological structure and working model of single-phase three-level rectifierThe topological structure of the main circuit of single-phase three-level rectifier is shown as Fig. 1. u represents the output voltage of the transformer secondary side traction winding; U and U represent the voltages of DC-side capacitor C and capacitor C . The two rectifier bridge arms consist of eight IGBT elements. If the switch elements of each bridge arm are replaced by an ideal three-level switch, the switch equivalent circuit can be obtained as shown in Fig. 2.