A Three-phase Rectifier Current Phase Shift Zero Crossing Distortion Correction Method

Abstract

The invention provides a correction policy of current zero-crossing distortion applicable to all one-way three-phase rectifiers (including three-phase VIENNA rectifiers, three-phase bridgeless rectifiers and all star-connection cascaded three-phase rectifier topologies) based on single-period control. The policy specifically includes following steps: firstly, determining related parameters of a system, then calculating a current distortion initial point, a distortion time and a boundary condition, and finally calculating a parameter introduced compensation amount based on the above parameters.According to the policy, based on the characteristic of single-period direct current control, crossed injection is performed on the feedback of current phase-shift control signals, and superpositionis performed with an original phase-shift feedback amount so that zero-crossing distortion generated by current phase shift of the energy one-way flow three-phase rectifier is corrected without increasing the complexity of the system. According to the policy, the realization is simple, the reliability is high, an effective correction method is provided for the current zero-crossing distortion problem occurring in a single-period control process, and the application range of single-period control is extended.

Description

technical field [0001] The invention relates to the field of power electronics and power system automation, in particular to a phase-shifting zero-crossing distortion correction strategy for a three-phase rectifier current with unidirectional flow of energy based on single-cycle control. Background technique [0002] Because in quite a lot of practical industrial applications, energy does not need to flow in two directions, such as fans that do not need energy feedback, energy-saving speed regulation of pump motors, and charging stations for automobiles, ships, and aviation. Therefore, rectifiers with unidirectional energy flow have received extensive attention in the field of power electronics technology in recent years. Compared with rectifiers with unidirectional energy flow, rectifiers with bidirectional energy flow use more fully-controlled devices, resulting in complex circuit control, poor system stability, and significant increase in project cost, so there is no obvi...

AI Technical Summary

Problems solved by technology

[0003] However, many rectifiers with unidirectional energy flow, such as three-phase VIENNA rectifiers, three-phase bridgeless rectifiers and all star-connected cascaded three-phase rectifier topologies, essentially cannot achieve true unity power factor due to the existence of input side inductance Running, the inductor current can only run in a sinusoidal waveform when it lags the power supply voltage at a suitable angle (the angle depends on the value of the inductor and the size of the load current), so when the current leads the power factor and lags the power factor (the lagging angle is greater than Original sinusoidal current lag angle) or unity power factor operation, the current will produce distortion near the zero crossing point, for the above problems, there is no effective solution

Therefore, the harmonic pollution of the power grid, the decrease of system stability and the decrease of service life have seriously restricted the development and application of rectifiers with one-way energy flow.

Moreover, the problem of current distortion is particularly prominent in three-phase rectifiers in which energy flows in one direction, because the zero-crossing distortion of each phase current will cause corresponding distortions in the other two phase currents at the same time, thus multiplying the damage of current distortion

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