Research And Design Of Active Power Filter Based On DSP

In modern life, the development of power electronics technology to bringconvenience to people’s lives at the same time, the application of power electronicstechnology also makes the power quality problems have become increasinglyprominent. Due to a large number of non-linear inductors, capacitors and otherdevices are power electronic devices, the large number of harmonics and reactivevoltage when these will be produced using a non-linear load current. After the deviceinto the grid will make the grid voltage, current, power utilization and reducedistortion, great harm not only to the power grid, but also to greatly increase the costof electricity users. So they came into power filter. LC filter initially poor dynamicperformance can not change the harmonic filter and easy with a grid harmonicresonance, so that the amplified harmonic flow into the grid, thereby increasing thedistortion of the grid. Relative to the LC filter, active power filter to overcome theabove drawbacks, has a good dynamic performance, while avoiding the possibleoccurrence of resonance. Therefore, active power filter has been more and moreattention and research.In this paper, shunt voltage APF as the main object of study, a detaileddiscussion of its working principle, active power filter system can be divided into thecommand current detection and compensation current tracking control in two parts.First, the command current detecting method in detail. To command current detectionalgorithm based on instantaneous reactive power theory, as this article detectionalgorithm focuses on the p-q law, law on the basis of the applicability of thisalgorithm in a variety of environments. The results can be seen in the law applies notonly to the power grid voltage distortion, asymmetric, and in three-phase four-wiresystem applies. Based on instantaneous reactive power law wider applicability, so thisarticle in this way as a command current detection methods. Then, in compensationcurrent tracking control of active power filter, the control methods used in this paperis based on the non-poor shot control space vector. This paper analyzes the hysteresiscontrol, triangle wave comparison with control voltage space vector control (SVPWM)their advantages and disadvantages. Relative to the hysteresis control, triangle wavecomparison control, SVPWM algorithm switching frequency is fixed, the main circuit DC voltage utilization compared to the other two algorithms improves, the equivalentof reducing the size of the DC side capacitor, saving costs, while easy-to-digitalimplementation. Given the shunt voltage APF own characteristics, between the activepower filter is connected to the grid through the inductor, so the process will generatea PWM signal that there is a differential equation, solving differential equationsdirectly in this difficult to achieve, for In this paper, a method for this problemdeadbeat control predictable, the discrete equations, by predicting the next time thecurrent instruction to solve this differential equation.Theoretical studies based on the above, this paper based on instantaneousreactive power law as a command current extraction method, based on SVPWMdeadbeat control to achieve the compensation current tracking control, active powerfilter set designed10KVA (the APF) systems. Including the main circuit systemdesigned to DSP (TMS320F2812) as the system controller chip control circuit designand control system software design. Times outside the established system usingMATLAB software simulation model, simulation results show that the design of thesystem harmonic and reactive current compensation to good effect.