Passivity-based control system for voltage type PWM rectifier supplied by unbalanced power supply

Abstract

The invention researches the problem of controlling a voltage PWM rectifier when a power supply is unbalanced according to a principle that the change of a physical quantity depends on energy changes. On the basis of the passivity of a novel synchronous rotation transformation and a rectifier, a new passive energy control law is determined. The novel synchronous rotation transformation can transform an unbalanced system of the PWM rectifier supplied by an unbalanced power supply into a quasiequilibrium system. The passive energy control law determined by a novel damping injection method can decouple a system, transform a non-linear system into a linear system, and simultaneously converge the rectifier to an expected stable point quickly. A passivity-based control system for the voltage type PWM rectifier supplied by the unbalanced power supply (referring to an attached figure) established based on the novel synchronous rotation transformation and the new passive energy control law has excellent movable and still performances, and achieves unit power factors, current on-line side sine, and direct current voltage constant control.

Description

technical field [0001] Based on the novel synchronous rotation transformation and the passivity of the rectifier, the present invention constructs a three-phase voltage-type PWM rectifier control system when the power supply is unbalanced, and can realize low harmonics, unit power factor, bidirectional flow of energy and constant DC voltage of the network side current of the PWM rectifier Control, can be applied to frequency conversion speed regulation system, DC power supply and other fields. It belongs to the field of power electronics technology and nonlinear control. Background technique [0002] In engineering practice, the power supply voltage is not an ideal balanced voltage (amplitude balance, phase balance), and various control strategies under power balance conditions are used to control the voltage-type PWM rectifier, so that the AC current on the grid side contains a large number of harmonics. Pollution to the grid reduces the power quality of the grid and also ...

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Problems solved by technology

These documents are based on the positive and negative sequence components of the unbalanced voltage, and propose different control strategies; for example, the double current inner loop control method can improve the input current harmonics and the output DC voltage waveform very well, and there is no optimization control algorithm Detailed and in-depth analysis of the instantaneous power in the grid, in fact, in the case of unbalanced input grid voltage, it is impossible to achieve zero reactive power, so as to achieve an input power factor of 1; due to the use of filters, PI regulators , the control effect on the nonlinear control object of the rectifier must be affected

At present, there is no better way to make the PWM rectifier realize low harmonic sinusoidal current on the grid side, unit power factor, and constant DC voltage control when the power supply is unbalanced.

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