dc to dc fourth quad..pdf

4-Quadrant dc chopper Circuit Diagram Switching state The 4-digit binary number (x1x2x3x4)2, where x1 through x4 denotes the chopper state. A total of 16 states can be represented. However, only states 0, 1, 4, 6, and 9 are utilized. The remaining states would either short-circuit the supply sourc...

4-Quadrant dc chopper Circuit Diagram Switching state The 4-digit binary number (x1x2x3x4)2, where x1 through x4 denotes the chopper state. A total of 16 states can be represented. However, only states 0, 1, 4, 6, and 9 are utilized. The remaining states would either short-circuit the supply source or spoil the symmetry of control. Four Quadrant Operation First Quadrant Operation  First Quadrant Operation The ON state is state 9 (or 1001) S1 and S4 are ON. The off state is state 1 (0001), only S4 is ON. This makes the state when S1 is ON =(1001)2 i.e. state 9 and when S1 is OFF =(0001)2 as stated in the same table. On State Off-State Second Quadrant Operation Second Quadrant Operation Third Quadrant Operation Fourth Quadrant Operation Example 1: A four-quadrant chopper operates with a switching frequency of 1kHz and supplies power to a dc motor whose armature EMF is –216 V. The input voltage of the chopper is 240 V. Find: (a) Voltage control ranges for the third and fourth quadrants of operation of the chopper (b) on-time and off-time of the modulating switch when the chopper operates in the third quadrant with the magnitude control ratio of –0.95 (c) on-time and off-time of the modulating switch when the chopper operates in the fourth quadrant with the magnitude control ratio of –0.75.