SVPWM strategy based on power supply topology of double three-level inverters

Abstract

The invention discloses an SVPWM strategy based on the power supply topology of double three-level inverters. According to the strategy, a gating signal of each switch device is obtained fast according to three-phase referential voltage signals, two inverters work alternately in each fundamental wave period, the average zero sequence voltage generated by the two inverters is zero in each switch period, and the midpoint electric potential is balanced based on the voltage signals of two direct-current-side capacitors. The SVPWM strategy based on the power supply topology of the double three-level inverters has the advantages that the modulation strategy is simple and fast, and coordinate change and complicated sector judgment and table look-up are not needed; the two inverters work alternately, the switching frequency of the switch devices is reduced by half, and the loss of the switch devices is reduced; after the average zero sequence voltage is eliminated, power supply of the two inverters can be achieved by only one direct current power source, the topology structure can be effectively simplified, cost can be reduced, and four-quadrant operation of a motor is facilitated.

Description

technical field [0001] The invention relates to the technical field of modulation of multi-level power electronic converters, in particular to a SVPWM strategy based on a dual-three-level inverter power supply topology. Background technique [0002] In the high-voltage and high-power motor speed control system, due to the increase of power and voltage levels, the withstand voltage and current-carrying capacity of switching devices are limited, and the two-level topology inverter is difficult to meet the actual industrial requirements. Since Nabae proposed the diode-clamped (NPC) three-level inverter topology in the early 1980s, the research on NPC three-level inverters has made great progress. Low, less impact on the insulation of the motor; the capacity of the converter is doubled; the power circuit structure is simple, which not only reduces the number of power devices used, but also increases the reliability of the converter; sharing the DC bus increases the system Sever...

AI Technical Summary

Problems solved by technology

In addition, in the power electronic converter, there is a certain energy loss in the switching device during the turn-on and turn-off process. With the increase of the switching frequency, the heating of the switching device will increase, which will affect the normal operation of the entire system in severe cases.

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