Hybrid Active Filter Control Strategy

With more and more non-linear loads used in power system, that causes too much harmonic pollution, and the power quality becomes worse sharply. It is imperative to deal with harmonics under the situation.The conventional passive power filter and active power filter both have disadvantages. But the hybrid active power filter composed of them can have their advantages and eliminate their disadvantages.At the same time it possesses the characteristics of low price of PPF and good performance of APF. It can make harmonic compensation system reach the best performance at the lowest cost, and is one of the trend of harmonic control. In order to get the perfect filtering performance and exert the advantage of HAPF sufficiently, it is very significant to do research on the control strategy of HAPF.The dissertation discusses the three main t topologies and their control strategies in details. Based on these, we mainly lucubrate the control strategy of Parallel Hybrid Active Power Filter—PHAPF for practical purposes. Compared with other topologies, the PHAPF has the best advantage of topology, and its integrated performance is the best. So the dissertation analyzes sufficiently the four basic control strategies of PHAPF: voltage source closed loop control strategy, voltage source open loop control strategy, current source closed loop control, current source open loop control strategy, and it also analyzes the capacity of APF in PHAPF using the novel capacity analyzing method proposed by this dissertation. The analyses indicate that current source open loop and voltage source closed loop control strategy have better utility value, but they still have disadvantages to improve.When the current source open loop control strategy is used in PHAPF, though it can achieve better filtering performance, it can't reduce the capacity of APF. So a novel current source open loop control strategy—fundamental current injection control strategy was put forward. The novel control strategy injects some fundamental current into Passive Power Filter—PPF, and compels PPF to bear the fundamental voltage, so that the APF doesn't bear the fundamental voltage and reduces the capacity...