Method for controlling model prediction current of low-loss voltage source inverter

Abstract

The invention provides a method for controlling model prediction current of a low-loss voltage source inverter. The method comprises the steps of: sampling load current of the inverter at k time and converting the load current into a current component in an alpha beta coordinate system by clake; acquiring 8 voltage vectors according to a switch status of the inverter; converting the voltage vectors corresponding to different switch statuses into the voltage components in the alpha beta coordinate system; predicting a current value at k+1 time according to the current component and the voltagecomponents; putting the current value into a first target function to calculate; combining each one zero vector with each one nonzero vector randomly from 8 voltage vectors; calculating the action time of each voltage vector combination; calculating a second target function to determine two groups of optimal combinations; and selecting one voltage vector combination to act on the inverter according to the three-phase load current. By adoption of the method provided by the invention, two vectors are used in each control period, so as to reduce the harmonic wave of the current; and, the method can be applied to the high-power photovoltaic grid-connected inverter or the motor drive controller, so as to reduce the system loss.

Description

technical field [0001] The present invention relates to the technical field of voltage source inverters in power electronics, in particular to the application of model predictive control in the control field of high-power voltage source inverters, and in particular to a model predictive current control method for low-loss voltage source inverters. It can be applied to applications such as model predictive control in photovoltaic grid-connected inverters and motor drive control. Background technique [0002] According to relevant research, nearly 60% of inverter failures are caused by temperature, and the failure rate doubles when the temperature rises by 10°C. The loss of the inverter is the direct cause of the temperature change of the power device. The greater the loss of the inverter, the higher the junction temperature of the power device will be. Requirements will also accelerate the aging and failure of power devices, reduce the service life of the inverter, greatly i...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the technical problem that the inverter output current has high harmonic content and cannot meet the requirements of grid-connected inverters or control systems, the present invention proposes a low-loss voltage source inverter model predictive current control method, in each control cycle Two voltage vectors are used to act on the inverter, thereby reducing the harmonic content of the output current

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