Multi-parallel inverter motor speed regulating system and control method thereof

Abstract

The invention discloses a multi-parallel inverter motor speed regulating system and a control method of the multi-parallel inverter motor speed regulating system. The system is formed by connecting multiple inverter modules in parallel. The direct current sides of multiple inverter sub modules are directly connected with a direct current power supply with a direct current bus capacitor in parallel. The alternating current sides of the multiple inverter sub modules are connected with multiple sets of smoothing reactors respectively in series and then directly connected in parallel to drive an alternating current motor. By the adoption of the structure, modularization expansion of the motor speed regulating system is easily conducted, and the fault-tolerance performance of the motor speed regulating system is enhanced. By means of a random SVPWM method based on carrier phase shifting, switching frequency of parallel inverters is equivalently improved, switching subharmonic energy within narrow frequency bands is equalized, the harmonic performance of output currents of the parallel inverters is improved, and electromagnetic interference resistance of the motor speed regulating system is enhanced. By the adoption of a space vector synthetic technology for dynamically allocating SVPWM zero vectors, zero-sequence circulating currents between the parallel inverter modules are effectively eliminated, and normal operation of the system is guaranteed.

Description

technical field [0001] The invention relates to an AC motor speed regulation system and a control method thereof, which are widely used in high-power AC motor speed regulation and electric energy conversion, and belong to the fields of power system, power electronics and motor control. Background technique [0002] At present, the research on the AC motor speed control system is mainly on the topological structure of the conversion circuit and the power electronic control strategy. Small. [0003] In order to meet the increasing requirements of the capacity of the motor drive system, parallel three-phase inverters are used to increase the capacity of the motor speed control system. Parallel connection methods include: (1) The DC side is independently powered by multiple power supplies, and the AC side is directly connected in parallel through a smoothing reactor; (2) The DC side is directly connected in parallel to a power supply, and the AC side is connected in parallel th...

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Problems solved by technology

[0005] In view of the shortcomings of the current parallel inverter motor speed control system that is not easy to be modularized and expanded, and the need for improvement in the traditional modulation technology and control strategy of parallel inverters, this invention proposes a multi-parallel inverter based on phase-shift random pulse width modulation Motor speed control system

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