| Active power filter (APF) and passive power filter (PPF) are both effective means for harmonic control, the single use of APF and PPF has their own advantages and disadvantages. Hybrid active power filter combined by APF and PPF, learning from both their strong points to offset their weaknesses,can be applied for high power harmonic control and reactive power compensation. But for this topology, delay and limitation of harmonic detection is so prominent that finding a solution to these problems is urgent.This paper analyzes a variety of hybrid active power filter circuit, focusing on the topology of injection parallel hybrid active power filter, and then produces main circuit and main parameters. Aiming at the limitation of traditional harmonic detection which can only detect the total harmonic current, this article extend this traditional ip-iq harmonic detection method to random harmonic current detection without PLL, which kind of algorithm is more suitable for hybrid active power filter topology. This method not only avoids the influence of decimal harmonic current for the DC voltage on the inverter, but also improves the current response rate of compensation.The article also details the comparison of the triangular carrier method and the hysteretic ring current tracking control method, improving the latter method, and the control method of DC voltage. Under the coordination of current inner loop and outer voltage loop, active power filter has a good compensation.Based on the harmonic detection algorithm and the current tracking control method, the control system based on DSP chip TMS320LF2407 is designed, and simulation proves that the improved harmonic detection method,which has high-speed current detection and good result in random harmonic current detecting, can be used to large-capacity harmonic current control. Timing hoop current tracking control method, which makes PWM signal change per clock cycle at least, can protect on-off aids from vitiating. |
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