The Optimization Design Of LC Filter In Uncontrolled Single-phase Rectifier Based On Visual Algorithm

With the rapid development of power electronics technolgy, the PWM controltechniques have been applied widely and shown its superiority in the rectifier circuit.However,in many applications such as AC-DC-AC inverter, switching power supplyand uninterruptible power supply,the DC power is mostly provided by uncontrolledrectifier with LC filter. In this paper, the LC filter for uncontrolled single-phase rectifieris as research subjects to be analyzed.Firstly, this paper presents the multidimensional visualization algorithms used foroptimization of power converter,mainly introduces the implementation procedure of4dand5d visualization algorithms.Then relevant theoretical knowledge about uncontrolledsingle-phase rectifier with LC filter has been expounded,including the work pattern ofcircuit,the design requirements and composion of LC filter, the related knowledge ofmagnetic.For the uncontrolled single-phase rectifier with LC filter,when the inductor islocated in the DC side of the rectifieer bridge,how to counteract the DC bias producedby inductor current has become a research tendency. By moving the inductor from DCside of rectifiers to AC side, the DC component can be eliminated directly, but theanalysis and optimization design of dynamic characteristics are more complex.Mathematical analysis of the transient of the single-phase diode rectifiers is presented.Using5D visualization, the changing processes of transient voltage and transient currentin the two different cases can be showed and it is proved that the surge voltage is lowerand the duration of over current is shorter. Moreover, under the same conditions, thecore utilization will be much higher,and the Ap’s value of the core is more smaller,whenAC inductor is used than when DC inductor is used.Which is conductive to optimizingthe volume of the inductor. The values of L,C can be choosed by optimizing the LCfilter parameters with AC inductor.Inductor, as the indispensable component in LC filter, is developing towardintergration and miniaturization. However, for a variety of reasons, such as multi-valuednonlinear of the core and the difficulty to obtain some valuable numerical solutions ofthe optimization design equations, so far the inductor’s research and development isoften done by the feasible design,and how to effectively optimize magnetic devices in power electronics technology becomes a major difficulty. Combined with magnetichysteresis loops under the silicon steel’s state with/without air-gap, this paper derives theexpression of equivalent permeability and solves the partial derivatives of the expressionwith the air gap length, then makes the equation equal to zero. the ratio for the length ofair-gap and the length of magnetic circuit to ensure maximum of the equivalentpermeability can be obersved by visualization. And at the same time, the parameters ofinductor is designed based on the method of APvalue. the paper solves the expressionfi(N,Ae, Aw) of each design objective like inductance, volume, loss, surface ortemperature rise. In the expressions Awis the window area, and Aeis the core section,and N is the number of turns. Moreover, the paper realizes the optimization designbased on the4D visualization of multi-objective and comparatively analyzes thevisualization design algorithm and the traditional design algorithm.Finally, thecorrectness of the theory is verified by the experimental results.In the circumstances ofsame indutance, the volume of AC inductor is smaller than the DC inductor. The resultindicates that the volume ratio of them is approximately1/2.