并網(wǎng)逆變器不平衡電網(wǎng)下的分析ppt課件

1、Grid-tied inverter under unbalanced grid voltage1;.2Backgroundabc/111222330322111222Taabc/bcxxxTxxx/abc1011312213122T ab/abccxxxTxxxThree phase variables (xa, xb, xc)-1 can be represented by a vector in the a-b-c coordinationThree phase variables can be transformed into coordination3BackgroundIf , t

2、he trajectory of the vector will be in the plate 0 x If the three phase variables are in three phase sine signal with the same amplitude and frequency of , and with the phase difference of 120 degree, the vector will rotate in the plate m0m0m0cos2cos32cos3VtVtVt+Xm0m0m0cos2cos32cos3VtVtVtXNegative s

3、equence rotate in clockwise directionPositive sequence rotate in counter-clockwise direction4Backgroundpdp/dqpqxxTxxndn/dqnnqxxTxxp/dqcossinsincosTn/dqcossinsincosTPositive rotation coordinationNegative rotation coordination5BackgroundqndnILVLThe model of inductor in POSITIVE & NEGATIVE rotation

4、 coordinationLqLdLdLqviLviL LqLdLdLqviLviL pIn the phasor diagram, the voltage leads the current by 90 degreepIn the sector diagram, the relationship also exists in both positive rotation coordination and negative rotation coordination pIn the positive rotation coordination, the VL and IL represents

5、 positive sequence only, they will rotate in counter-clockwise and VL must lead IL (the leading direction is counter-clockwise)pIn the negative rotation coordination, the VL and IL represents negative sequence only, they will rotate in clockwise and VL must lead IL (the leading direction is clockwise)6BackgroundRotating coordinationPositive sequenc