Fully active harmonic control device combining full compensation and fractionated compensation of a plurality of machines

Abstract

The invention discloses a fully active harmonic control device combining the full compensation and fractionated compensation of a plurality of machines. A full compensation unit is used for compensating for high-band harmonics comprising high-frequency ripple current injected into a power grid by a low-band power unit. A fractionated compensation unit is used for compensating for harmonics of given low bands. The multiple running of power units of compensation groups of the same band improves harmonic compensation accuracy. The switching frequency and compensating capacity of the power unit are inversely proportional, so the finite compensating capacity of the power unit can be maximized by the compensation scheme. By the device, current detection is performed at both a power grid side and a load side, a master controller is used for the operation and distribution of compensation command current, and each slave controller is used for closed loop control over the compensating current of the power unit. The device can compensate for the harmonics of given orders and higher harmonics, and simultaneously has quick response, relatively higher compensation accuracy, high feasibility and high practical value.

Description

technical field [0001] The invention belongs to the technical field of power electronics application, and in particular relates to a multi-machine full compensation and sub-compensation combined type fully active harmonic control device. Background technique [0002] The wide application of power electronic devices makes the harmonic content of the power grid continue to rise, and the harmonics have the following hazards to the operation of the power system: ① increase transmission line loss ② consume reactive power reserves ③ cause large errors in power measurement ④ affect power processing The normal operation of the device ⑤ causes the automatic control and protection device to work disorderly, and the reliability decreases. At present, the methods for suppressing harmonics mainly use passive filters (PF) and active filters (APF), and hybrid filtering methods based on these two methods. When the harmonic current that needs to be compensated is large, the size and weight ...

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Problems solved by technology

However, when compensating for high-order harmonics, the switching frequency will be very high, resulting in limited compensation capacity, which is not suitable for high-current applications

The second solution combines multi-machine full compensation with a passive filter. Due to the large current on the low-voltage side, its harmonic current is also relatively large, making the volume and weight of the passive filter large, and it is also not suitable for applications. In high current occasions

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