Method for suppressing active circulation with parallel three-phase inverters

Abstract

The invention provides a method for suppressing active circulation with parallel three-phase inverters. The method for suppressing the active circulation with the parallel three-phase inverters comprises the following steps: sending the time variable Tu0Ns which represents the control action of each module zero sequence voltage in a three-phase inverter parallel system to a digital CAN communication bus, wherein any one inverter module can receive the components Tu0Ns of other inverter modules; completing average value calculation on the component in each control system by the three-phase inverters; taking the difference between the average value calculation and the time variable Tu0N of the self control action of the zero sequence voltage as a feedforward compensation amount of a zero sequence current control loop of the inverter module; combining output of a zero sequence current control channel with non-zero voltage vector acting time obtained by modulation and output of the SVPWM when dq axis decoupling control is adopted by the parallel system; and adjusting the zero voltage vector acting time according to a linear distribution mechanism, and obtaining on-off control signals of each bridge arm power device of a single three-phase inverter. The method for suppressing the active circulation with the parallel three-phase inverters improves current balance controlling ability of each parallel inverting module under the condition that extra hardware cost, size and weight are not increased.

Description

technical field [0001] The invention relates to a method for suppressing circulating current in an inverter parallel system. Background technique [0002] Due to the rapid development of power electronics technology and its expanding application fields, many devices have put forward higher and stricter new requirements for the reliability, power capacity, and performance of the power supply system. The traditional centralized power supply method These requirements can no longer be met. In the inverter parallel system, each module shares the load current to facilitate energy distribution; it has redundant functions and high system reliability; at the same time, it has the advantages of easy modularization, standardization, and good maintainability. Therefore, it is widely used in power supply systems for important and sensitive loads, such as finance, aerospace and other important departments and fields. Parallel inverter technology can easily realize high reliability, high...

AI Technical Summary

Problems solved by technology

In order to reduce the size and cost of inverters running in parallel, some scholars have proposed to use phase-to-phase impedance to provide high zero-sequence component impedance, but the phase-to-phase impedance is relatively large at medium and high frequencies, and relatively small at low frequencies. Therefore, this method cannot suppress low-frequency circulation very well.

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