Harmonic quality control strategy for single distributed resource of islanded microgrid at low switching frequency operation

Abstract

Active front-end converters are part of high power installations for regenerative energy systems, feeding the regenerated energy into the utility. Under the island mode operation of the regenerative energy system, the load characteristics are difficult to detect, and the change of the load characteristics will cause the corresponding resonance. V/f control is usually used to ensure the harmonic quality. At high switching frequency, it has a good control effect. However, high switching frequency causes high switching loss. In order to reduce the switching loss, it will produce more harmonic distortion. Furthermore, the commonly used modulation strategies in this case face the problem of low real-time performance. Therefore, in order to avoid the harm caused by circuit resonance under the condition of reducing the switching frequency, this paper proposes a specific harmonic suppression algorithm with high real-time performance, which can be used as an optional control algorithm in the island operation state of power system. At the same time, aiming at the difficulty of adjusting the weight factors, this paper proposes a weight factor automatic tuner, which automatically adjusts the weight factors according to the harmonic component.

Keywords

• Space Voltage Vectors
• Active Front-End Converters
• Harmonic suppression
• Low switching frequency
• Predictive control