Current tracking control method

Abstract

The invention provides a current tracking control method. For a hybrid rectifier including a three-level PWM boost rectifier, the current tracking control method comprises the steps of obtaining three-phase given current, acquiring three-phase input real-time current of the hybrid rectifier, sorting three-phase input phase sequences of the hybrid rectifier according to three-phase set duty ratio from small to big, obtaining the breakover time Tx, Ty and Tz of a three-phase switch in a working period according to a circuit structure of the hybrid rectifier, judging whether 0<Tx<Ts / 2, 0<Ty<Ts / 2 or 0<Tz<Ts / 2 is established or not; correcting the Tx, Ty or Tz; obtaining the three-phase duty ratio of the three-phase switch; respectively performing breakover or turnoff of the corresponding three-phase control switch according to the three-phase duty ratio after pulse width modulation so as to achieve current tracking. The current tracking control method has the advantages of being high power factor, low in harmonic distortion rate and the like and can be widely applied to the field of current tracking control.

Description

technical field [0001] The invention relates to control technology, in particular to a current tracking control method. Background technique [0002] In order to adapt to the development of social needs and scientific and technological progress, rectifiers, which are common electrical devices in civil and industrial fields, are also continuously improved. In recent years, foreign scholars have proposed a hybrid rectifier composed of different types of rectifiers connected in series or parallel. For example, a three-level PWM boost rectifier and a single-switch three-phase boost rectifier are connected in series or in parallel to form a three-phase three-level hybrid rectifier. ; Wherein, the three-level PWM boost rectifier is used in the three-phase three-level rectifier to compensate the current waveform of the single-switch three-phase boost rectifier, and forms a sinusoidal current synchronous with the grid voltage on the AC grid side. figure 1 It is a schematic diagram ...

AI Technical Summary

Problems solved by technology

The current tracking control methods of the above-mentioned hybrid rectifier mainly include linear control method, hysteresis comparison method, etc. These control methods are relatively complicated, and the control accuracy is low, the switching frequency is not constant, and the switching loss and noise are relatively large. Therefore, the above-mentioned hybrid rectifier The power factor is low and the harmonic distortion rate is large

[0003] It can be seen that in the prior art, the current tracking control method has problems such as low power factor and large harmonic distortion rate.

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