A rectifier and its control method and control system

Abstract

The present application discloses a rectifier and a control method and control system thereof, including: determining an error between a DC voltage output by the rectifier and a DC reference voltage, and determining an expected resistance value to be simulated at a port of the rectifier based on the error; The grid current at the input end and the simulated harmonic impedance determine the harmonic compensation voltage for compensating harmonics; through the estimated value of the equivalent inductance of the rectifier, determine the simulated negative inductance of the rectifier port, and determine the negative inductance through the negative inductance. The inductance voltage drop compensation value used to compensate the inductance voltage drop of the rectifier; according to the expected resistance value, harmonic compensation voltage and inductance voltage drop compensation value, determine the current required voltage reference value of the rectifier port to modulate the PWM pulse and carry out Drive control of the rectifier. By applying the solution of the present application, when there is no grid voltage sensor, the current harmonics of the rectifier are effectively reduced, and a high power factor is achieved.

Description

technical field [0001] The invention relates to the technical field of AC / DC power conversion, in particular to a rectifier and a control method and control system thereof. Background technique [0002] As more and more nonlinear loads are used, the power quality is getting worse and worse, and the problems of loss and electromagnetic interference tend to be serious. Active rectifier has the advantages of controllable input power factor and sinusoidal input current. It is an effective solution to improve power quality, which can improve power quality from the source. [0003] At present, by sampling the grid voltage and grid current, many controllers can well achieve high power factor operation of the rectifier and good current control under grid distortion conditions. However, grid voltage sensors and grid current sensors are expensive compared to the total cost of the control system. In addition, the solution without grid voltage sensor is also beneficial to improve reli...

AI Technical Summary

Problems solved by technology

However, in the current schemes without grid voltage sensors, the sensorless control scheme based on the observer is commonly used. Due to the limited bandwidth of the observer, the distortion of the grid voltage cannot be well suppressed, resulting in high current harmonics.

In addition, without the control of the grid voltage sensor, it is usually difficult to achieve high power factor

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