Multi-target satisfactory optimization pulse width modulation policy of three-phase voltage source type inverter

Abstract

The invention discloses a multi-objective satisfaction optimization pulse width modulation strategy for a three-phase voltage source inverter, which includes three parts: a two-level voltage source inverter, global optimization PWM, and switching loss optimization. The present invention first obtains the global optimal solution corresponding to the three optimization objectives of linear modulation range expansion, output current ripple loss and switching loss by solving the mathematical programming model of the special solution of the volt-second balance equation group within a single carrier period. Secondly, a multi-objective satisfactory PWM based on online programming of special solutions of volt-second balance equations is proposed. Finally, the importance of each control objective is flexibly adjusted by adjusting the switching loss coefficient limit to meet the needs of different application fields.

Description

Technical field [0001] The invention relates to a three-phase voltage source inverter, in particular to a multi-objective satisfaction optimization pulse width modulation strategy of the three-phase voltage source inverter. Background technique [0002] Two-level voltage source inverters (two-level voltage source inverters, 2L-VSI) are widely used in new energy power generation, uninterruptible power supply, power quality control, electric vehicles and other fields. For 2L-VSI, people tend to focus on optimizing one or more indicators on the basis of pursuing satisfaction with multiple indicators. In different application fields, the focus of 2L-VSI control indicators is different. For example, in the field of electric bicycles, the focus is on simplifying the pulse width modulation (PWM) strategy to ensure that low-cost digital chips can effectively complete calculations; in the field of power quality management, output harmonics are the priority control indicators to reduc...

AI Technical Summary

Problems solved by technology

In view of the problem that the total harmonic distortion (THD) of the 2L-VSI output is relatively large, the intelligent control algorithm (such as neural network, immune algorithm, genetic algorithm, etc.) is used to calculate the switching time of the inverter, which effectively reduces the Output harmonics and weaken the influence of system nonlinearity on modulation performance, but the calculation is too large

Aiming at the problem of large switching losses of power switching devices, the discontinuous pulse width modulation (discontinuous pulse width modulation, DPWM) can realize upper or lower bus bar clamping in several carrier cycles to reduce the actual switching frequency, but compared with continuous PWM , DPWM does not have the phenomenon of harmonic sideband elimination, which increases the weighted total harmonic distortion (WTHD)

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