Current cooperative control method for upper and lower busbars used in parallel operation of current source rectifiers

Abstract

The invention discloses a current synergistic control method for the upper and lower busbar currents of current source rectifiers in parallel operation. The upper and lower busbar currents of two rectifiers are sampled and filtered, and then the error between the output current and the reference current of the upper busbars of the two rectifiers is sent to the The proportional integral controller is used for adjustment to obtain the delay angle required for modulation. In addition, the difference of the lower bus current is sent to the proportional integral controller to calculate the bypass pulse width control parameter. The combination of the two can flexibly adjust the output current of the upper and lower bus, and realize the coordinated control of the upper and lower bus currents when the rectifiers are connected in parallel. Purpose.

Description

technical field [0001] The invention relates to a method for synergistic control of upper and lower busbar currents in the parallel environment of multi-current source rectifiers, which can effectively solve the overload problem of a single rectifier under the parallel working condition of multi-current source rectifiers. Background technique [0002] Due to the advantages of simple structure, good short-circuit current blocking characteristics, and natural bidirectional power flow capability, PWM current source converters are widely used in high-power applications such as medium-voltage transmission, high-voltage direct current transmission, renewable energy grid connection, and superconducting energy storage. scene is widely used. In these application scenarios, since the switching frequency of the current source converter is usually lower than 1Khz, the switching loss of the high-power converter can be reduced. [0003] Generally, there are two modulation methods for hig...

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Problems solved by technology

However, when the space vector modulation technique is applied to the current source rectifier, it will produce harmonic distortion, especially for high-power converters, when the switching frequency is very low operating conditions

In addition, in the application of high-power current source rectifier, when the sampling frequency of the space vector modulation technique is close to the natural resonance frequency of the output LC filter, the space vector modulation technique may inversely amplify the parallel resonance of the filter

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