Slip power recovery schemes EDC

PRESENTATION BY Mr.S.DAISON STALLON AP/EEE NEHRU INSTITUTE OF ENGINEERING AND TECHNOLOGY COIMBATORE.9489745477

1. SLIP POWER RECOVERY SCHEME PRESENTED BY MR.S.DAISON STALLON Mtech,mba ( phd ) AP/EEE NIET

2. It is used to control the speed of the slip ring induction motors. The speed control of the IM can be obtained either above or below synchronous speed. Stator voltage control and rotor resistance control have poor efficiency at low speed range and suitable for limited applications.

3. In order to improve the performance of the system like efficiency and capacity of the drive. If the slip power of the SRIM can be returned to the supply systems. Thus the over all efficiency can be increased.

4. Slip power recovery scheme types KRAMER DRIVE SCHERBIUS DRIVE FURTHER CLASSIFIED INTO CONVENTIONAL SLIP POWER RECOVERY SYSTEM STATIC SLIP POWER RECOVERY SYSTEM

5. KRAMER SLIP POWER RECOVERY SYSTEM This type is used to control the speed of an IM below rated speed. This can be obtained by either conventional or static. Conventional Kramer drive system Improved Kramer drive system Static Kramer drive system

6. This type consists of SRIM,DC MOTOR,ROTARY CONVERTER. The slip ring of the SRIM is connected to the input of the rotary converter. It converter AC into DC voltage and fed to the DC motor terminals. The DC motor shaft is connected with the shaft of the SRIM. The DC Motor shaft is connected with the shaft of the SRIM.

7. The Speed of the SRIM is controlled by varying field regulator of the DC Motor. The field regulator is connected separate DC bus. This type is also known as CONSTANT POWER CONTROL. In case if rotory converter is overexcited, it will take leading current which compensates for the lagging current draw by SRIM. Hence power factor of the system can be improved. This type is only preferred 4000 kw and above power level.

8. Modified or improved Kramer system with diode

9. With thyristor or scr

10. In this system the mechanical rotory converter is replaced by 3 phase diode bridge rectifier. The slip power of the rotor is fed to the input of the 3 phase diode bridge rectifier. It converts AC into DC and its ripple filtered by series connected inductor. The filtered DC output voltage is fed DC motor armature terminals. The DC motor shaft is connected with the shaft of the SRIM.

11. The Speed of the SRIM is controlled by varying field regulator of the DC motor. The field regulator is connected with separate DC bus. The control speed range is zero to around the synchronous speed by varying firing angle of thyristor. Diode is replaced by SCR for high power applications.

12. Static type Kramer slip power system

13. This system is very popular in large pump and fan drives. Where range of speed control is limited near, but below synchronous speed. This drive system is efficient but power converter is very low. This system is also called constant-torque drive.

14. Speed –torque chara

15. Advantages This system of speed control is economical because the rectifier and inverter only have to carry the slip power of the rotor. Which is less than the input power to the stator Its quite simple and stable.