| High frequency and high-power ESP power supply can significantly improve the collectionefficiency, and plays an increasingly important role in environmental protection, with theimplementation of energy-saving and emission reduction policies and more and more strict airpollution emission standards, at present high frequency and high-power ESP power supply hasbecame an important research area. Although the high frequency ESP power supply products ofdomestic enterprises gradually access to markets and be increasingly widely applied, comparedwith foreign products, there is a great gap between the parameter design and energy transferefficiency. Therefore, studying on the basic common problem and optimized control strategyabout the high frequency and high-power ESP power supply has important theoretical andengineering value.Firstly, this paper started from the basic issues and particularity of the ESP power supply,gave the mathematical description of each resonant phase comprehensively in discontinuouscurrent status and under the different working modes of the series-parallel resonant circuit. Byfurther analyzing the mathematical expressions, deduced a series of mathematical expressionswhich reflected the electrical characteristics of the circuit. While these expressions need a largeamount of computation and the internal relationship between the circuit parameters isindeterminate, it is difficult to optimize the design. Thus, the third chapter based on the electricalcharacteristics of the series resonant circuit, and applied normalization theory to normalizedelectrical characteristics of the series-parallel resonant circuit, then derived normalized analyticalexpressions in the simple form which contains only two parameters, the ratio of the outputvoltage to the input voltage and the ratio of the shunt capacitance to the series capacitor. Thispart of study revealed the intrinsic link between the circuit parameters, established the theoreticalfoundation for the parameters design of the high frequency and high power ESP power supply.Secondly, the paper presented the concept of critical intermittent switching frequency, anddesigned a simple control scheme which could be used when rated operating frequency is less than the minimum critical intermittent switching frequency and a optimized control programused when rated operating frequency is in the point of critical intermittent switching frequency.The simulation results showed that the optimized control scheme had higher boost ratio andmore transfer efficiency. Based on these advantages, the paper designed a FM voltage regulatorPID closed-loop control system which based on the optimized control scheme. Finally, the paperpresents an algorithm of best spark frequency control of Three-Line Segments Method whichwas focusing on controlling the voltage rise rate. In addition, the paper also carried out a detailedanalysis and design on how to achieve the sensitive and accurate spark detection which based onthe change of the secondary voltage, the secondary current and the resonance current.This paper has systematically researched the parameters design and optimized controlmethod for high frequency and high-power ESP power supply, and its results not only enrich thestudy of high frequency and high power ESP power supply, but also establish a good foundationfor the engineering application of the high frequency and high-power ESP power supply. |
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