Rectifier and control method and control system thereof

Abstract

The invention discloses a rectifier and a control method and system thereof, and the method comprises the steps: determining an error between a DC voltage outputted by the rectifier and a DC reference voltage, and determining an expected resistance value needed to be simulated by a rectifier port based on the error; determining harmonic compensation voltage for compensating harmonic according to the power grid current of the input end of the rectifier and the simulated harmonic impedance; according to the equivalent inductance estimation value of the rectifier, determining negative inductance needing to be simulated at the port of the rectifier, and determining an inductance voltage drop compensation value used for compensating the inductance voltage drop of the rectifier through the negative inductance; according to the expected resistance value, the harmonic compensation voltage and the inductance voltage drop compensation value, determining a currently required voltage reference value of a rectifier port so as to modulate PWM pulses and perform driving control of the rectifier. By applying the scheme of the invention, the current harmonic of the rectifier is effectively reduced without a power grid voltage sensor, and a high power factor is realized.

Description

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

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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