Tham khảo tài liệu 'advances in solid state part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Directional Tuning Control of Wireless Contactless Power Pickup for Inductive Power Transfer IPT System 231 S1 S2 Previous -State S3 Next-State S4 0 0 0 1 0 0 1 0 0 1 0 0 0 1 1 1 1 0 0 0 1 0 1 1 1 1 0 1 1 1 1 0 Table 1. Truth table for LS2 increasing direction determination. The simplified Boolean expression corresponding to Table I and the actual output signal of the controller can be expressed by S4 S3 Sj S2 S3 Sj S2 9 U k U k -1 - 1 S4 1 Ah 10 where U k is the present-state control signal U k-1 is the previous-state control signal and Ah is the step-size of the adjustment. Fuzzy logic control for automatic selection of tuning step-size Ah Despite the fact that the DTC algorithm can effectively control the output voltage of the pickup the control quality is still restrained by the predefined tuning step-size. A larger step change in the inductance often causes chattering of the output voltage. Although the chattering effect can be reduced by using smaller step change in the inductance it causes the overall response to be sluggish. To overcome the difficulties associated with the chattering problems and to make the overall response fast a fuzzy logic controller is integrated with the classical DTC algorithm to further improve the performance of the controller Hsu et al. 2008 . The objective of the fuzzy logic controller is to dynamically determine the step change Ah of the tuning inductance in 10 . Fuzzification Design of the fuzzy controller consists of fuzzification formulation of control rule base and defuzzification. In the process of fuzzification operating region of the controller is designed to allow error and rate of error to lie inside a predetermined interval -L L . The inputs to the fuzzy PI controller are given as GE e n GE yr n - y n 11 GR r n GR e n - e n -1 12 GR r2 n GR e nị - e n -1 13 where y n is the output voltage yr n is the reference signal e n is the error signal GE and GR are scaling factors for the error and the rate of error .
