The document discusses the simulation of a slip power recovery scheme (SPRS) for slip ring induction motors using GTO inverters and choppers in MATLAB. It outlines the types of SPRS, applications, and the operational principles of the 3-level IGBT inverter, highlighting its efficiency in DC-AC conversion and harmonic distortion reduction. The results indicate significant energy savings and performance improvements when employing this scheme in industrial applications.

1. SIMULATION OF SLIP POWER RECOVERY
SCHEME OF SRIM DRIVES USING GTO
INVERTER & CHOPPER USING MATLAB
A Presentation by-
2018BTEEL00012 Prathamesh Baburao Gosavi
2018BTEEL00016 Akash Vilas Sonawane
2018BTEEL00019 Sudarshan Dhananjay Gapat
2018BTEEL00020 Jayant Dilip Bodke
2018BTEEL00034 Chaitanya Subhash Powale

2. INTRODUCTION:
 What is SPRS?
Slip Power Recovery System (SPRS) is a variable speed drive for slip ring induction
motors. It recovers and delivers the slip dependent rotor power from the motor to the
grid. At changeover speed, SPRS is connected to the rotor and the rotor resistance is
disconnected.

3. TYPES OF SLIP POWER
RECOVERY SCHEMES:
There are two types of slip power
recovery control methods:
1. Static Kramer drive
2. Static Scherbius drive
1.Static Kramer drive
2.Static Scherbius drive

4. APPLICATIONS OF SPRS:
1. Large-capacity pumps and fan drives
2. Variable-speed wind energy systems
3. Shipboard VSCF (variable-speed/constant frequency) systems
4. Variable speed hydro-pumps/generators
5. Utility system flywheel energy storage systems

5. Block Diagram:
3 Phase SRIM
Diode
Rectifier
Inverter
To mains or
other
apllicances

6. 1. The slip power in rotor side is first converted into DC using three phase diode
rectifier.
2. The DC current is then smoothened by using inductor.
3. This DC power then can be used to operate other appliances.
4. The can also be converted into AC by using 3 Level IGBT based Inverter.
5. This AC power can be fed by to the mains or can be used for other appliance as a
source.
SPRS Using Diode Rectifier And 3 Level IGBT
Based Inverter

7. • In this Inverter each phase will switch across three voltage levels
(+V dc/2, 0,and -Vdc/2).
• The maximum voltage across the IGBT is limited to half the maximum dc
link voltage (Vdc/2).
• This occurs because the IGBTs are connected to the neutral point (MP) by
two fast diodes called neutral clamp diodes.
• The gate pulse is applied through a sinusoidal PWM generator block .
Working Of 3 level IGBT based Inverter :

8.  The use of multilevel inverters is a simple way of improving efficiency in dc-ac
conversion.
 The inverter produces an output waveform very close to a sinusoidal wave, with
extremely low harmonic distortion levels.
 The switching frequency can be lower than that of a typical two-level application,
allowing for reduced silicon losses.
 Multi level inverters draw line current with minimum distortion.
Why To Use 3 Level IGBT Based Inverter :

9. • Asynchronous Machine SI Units
• AC Voltage Source
• Bus Selector
• Diode Rectifier Bridge
• Series RLC load
• Three Level Inverter
• SPWM Block
• Three Phase V-I Measurement
• 3 Phase Power Measurement(phasor)
• Scope & display
Simulation Blocks:

10. MATLAB Simulation Model :

11. SPWM Custom Block

12. A]Motor Waveforms:
1) Stator Current:
2) Rotor Current:
RESULTS:

13. 3) Rotor Voltage
4) Rotor Speed

14. 1)Voltage
2)Current
INVERTER OUTPUT:

15. Motor Used: 415V , 1500 W, 1400 rpm, 3 phase SRIM motor
 DC output Voltage after Diode rectifier :
 Inverter Output Power : 120W
 % Power Recovered =( 120/ 1500 )*100 = 8%
For a 1000 kW fan, with SPRS the energy saving could be around 200 kW or 4800
kWh per day, equivalent to a saving of Rs. 20,000 @ Rs. 4.20 per unit (one kWh) of
energy ( ref: L&T Automation quotation)

16. CONCLUSION
 Effective way of slip recovery of Induction motor
 Increase in Efficiency
 Gain in Active Power by about 10%
 Total Harmonic Distortion (THD) within acceptable limits
 Output waveforms of Three Phase Inverter and Three Level Inverter
 Obtained relation between the Slip recovered power and the slip of
Induction Motor

17. Future Scope
 The power factor, efficiency and THD can be taken as parameters to examine
the enhancement in performance of SRIM drive.
 An optimum circuitry and implementation of converter with high frequency
performance along with induction motor are the needs to be taken into
consideration to increment the performance.
 High performance frequency converters enable very effective motor control
by providing the possibility of slip compensation as well as improvement of
power factor of the system.

18. Future Scope
 Further the scope of development can be found in our needs and in our
requirements. The various requirements such as operation of motor at
variable speed with reduced reactive power and lower value of THD can be
met with by using a latest technology of multi-level inverter.
 These improvements in the performance characteristics of SRIM drive can be
offered by GTO inverter and buck-boost chopper-based slip power recovery
scheme (SPRS)
 Results have suggested that the application of SRIM drive using SPRS with
GTO inverter and chopper control has superior performances than with SCR
inverter control.