Optimization and modulation method of duty ratios of five-bridge-arm voltage source inverter

Abstract

The invention relates to the field of power converters of drive motors, in particular to an optimization and modulation method of duty ratios of a five-bridge-arm voltage source inverter. The method includes the steps that three-phase stator currents of two motors are converted into dq axial current components under a two-phase rotating coordinate system through abc coordinates and dq coordinates respectively; PI controllers are adopted in rotating speed loops and current loops; required duty ratio reference values of drive signals of the two motors are generated by using voltage reference values of direct current bus voltages under a two-phase static coordinate system and through space vector pulse width modulation; the duty ratios are optimized and modulated in each sampling period. By the adoption of the optimization and modulation method, it is guaranteed that a common bridge arm can control the two motors at the same time in the modulation period, the control decoupling problem of the two motors is solved, the time of the two motors for being controlled by zero voltage vectors is effectively shortened, the utilization rate of the direct current bus voltages is improved, and the speed regulating range of a system is expanded.

Description

Technical field [0001] The invention relates to the field of power converter control for driving motors, in particular to a modulation method for a five-bridge arm inverter driving two motor systems. Background technique [0002] In recent years, with economic transformation and industrial upgrading, industrial production such as rail transit, papermaking, textiles, and metallurgy urgently needs multi-motor high-performance coordinated control technology, and multi-motor drive and control technology has also become a research hotspot in the scientific research community. [0003] At present, for two three-phase motors, a dual voltage source inverter is usually required to control them, and the modulation strategy generally adopts space vector pulse width modulation. With the development of modern power electronics technology on multi-phase voltage source inverters, a new way has been opened up for the drive of multi-motors. Among them, the five-arm voltage source inverter (...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of voltage utilization rate and speed regulation range in the five-arm inverter driving two motor systems, and propose a duty-cycle optimization modulation method of the voltage source inverter to ensure that the common bridge arm can be Simultaneously control two motors in the modulation cycle, solve the decoupling problem of the control of the two motors, effectively reduce the time for the two motors to be controlled by zero-voltage vector control, improve the utilization rate of the DC bus voltage, and expand the speed regulation range of the system

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