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SIMULATION OF MULTIMODE DC-DC CONVERTER FOR EV APPLICATIONS
- 2. ABSTRACT This studyfocuses on a universal power electronic interface that can be utilized in any type of the electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles. Basically, the proposed converter interfaces the energy storage device of the vehicle with the motor drive. The proposed converter is capable of operating in all directions in buck or boost modes with a non inverted output voltage and bidirectional power flow.
- 3. CONTENTS Introduction Blockdiagram Flow chart Operating modes Control systems Schematic diagram Simulation diagram Results Advantages Conclusion
- 4. INTRODUCTION The proposedtopology is suitable not only for conversion approaches but also is a good candidate to reduce the number of dc/dc converters from two to one in commercially available vehicles. DC-DC converters are widely preferred in order to obtain quality power,improves efficiency. By using SRM motor drive high speeds can be obtained.
- 5. BLOCK DIAGRAM MOTOR DRIVE AC/DC CONVERTER DC/DC CONVER -TER ENERGY STORAGE AC/DC CONVERTER MOTOR DRIVE DC/DC CONVERT -ER SS ENERGY STORAGE BLD CAA SRM BLDC Dc link Dclink ~ acceleration braking acceleration braking rectifying inverting recharging discharging discharging rechargingrectifying inverting Vbatt Vbatt Vdc Vrec Vrec Vdc
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- 7. PROBLEM DESCRIPTION Indriving mode, usually the battery voltage is stepped-up during acceleration. DC link voltage is stepped-down during braking, where Vdc>Vbatt. If motor drive’s nominal voltage is less than battery’s nominal voltage,Vdc<Vbatt, the battery voltage should be stepped-down during acceleration and the dc link voltage should be stepped-up during regenerative braking.
- 8. PROBLEM SOLUTION Whenall these possibilities are considered, the need for a universal bidirectional dc/dc converter is obvious which should be capable of operating in all-directions with stepping-up and stepping-down functionalities. Such a universal converter would meet all the needs of the auto industry. The proposed converter in this manuscript not only fulfils these conditions, but also can be utilized for retrofit conversion of conventional cars to HEVs as well as the HEV to PHEV conversions.
- 9. OPERATING MODES Case 1:Vdc<Vbatt Modes 1.Vdc→Vbatt Boost Mode for Plug-in Charging and Regenerative Braking: 2.Vbatt→Vdc Buck Mode for Plug-in Discharging and Acceleration: Case 2:Vdc>Vbatt Modes 3.Vdc→Vbatt Buck Mode for Plug-in Charging and Regenerative Braking: 4.Vbatt→Vdc Boost Mode for Plug-in Discharging and Acceleration:
- 10. CASE1:OPERATING MODES Vdc tovbatt boost mode of operation
- 11. Vbatt to vdc buckmode of operation
- 12. CASE2:OPERATING MODES Vdc tovbatt buck mode of operation
- 13. vbatt to vdc boostmode of operation
- 14. OPERATION MODES OFTHE PROPOSED CONVERTER
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- 16. DC/DC CONVERTE’S CASCADED CONTROLLERFOR DRIVING MODE
- 17. SCHEMATIC DIAGRAM POWER ELECTRONICINTERFACES IN AN ELECTRIC VEHICLE
- 18. EXPERIMENTAL CONDITIONS AND CIRCUITPARAMETERS
- 19. BRUSHLESS DC MOTOR A brushless dc motor is also viewed as ‘inside-out’ dc motor. A brushless dc motor has permanent magnet field poles on rotor and polyphase armature Winding on stator. Brushless dc motor system Combines into an ac motor, solid state inverter and a rotor position sensor. Torque=3/2KIm
- 20. SWITCHED RELUCTANCE MOTOR Variable reluctance motor is also known as switched reluctance motor. It has concentrated windings on stator poles and no windings on rotor. Torque=1/2i^2dL/dq
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- 22. BOOST MODE OFOPERATION vdc to vbatt -mode1
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- 24. BUCK MODE OFOPERATION vbatt to vdc -mode2
- 25.
- 26. BUCK MODE OFOPERATION vdc to vbatt –mode3
- 27.
- 28. BOOST MODE OFOPERATION vbatt to vdc –mode4
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- 30. EFFICIENCY -LOSS ANALYSISAND COMPARISIONS WITH EXISTING APPROACHES The proposed converter is compared with fundamental buck or boost dc/dc converters for each of its modes, the switching losses are identical since the proposed converter has only one switch in PWM mode in all of the modes. The additional conduction loss is mainly due to the additional switches or diodes in the current flow paths of the proposed converter.
- 31. When theconverter is operated in boost mode from dc link to the battery, the switching losses are the same,diode conduction loss would be PD = vF .IF , while the IGBT conduction loss would be PT = vCE(SAT).ICE. Change in losses can be expressed as ΔPloss,1 = PD1 + PT 1 + PT 4. (1) When the dc/dc converter is operated in buck mode from battery to the dc link, the additional conduction loss is due to diode D2,D3 and the switch T2. ΔPloss,2 = PD2 + PD3 + PT 2. (2)
- 32. Similarly, whendc/dc converter is operated in buck mode from dclink to the battery, additional conduction losses occur due to diodes D1 and D4 and the conducting switch T4 is given as ΔPloss,4 = PT 4 + PD1 + PD4. (3) When the dc/dc converter is operated in boost mode from battery to the dc link,conduction losses are due to a pair of additional conducting switches T2 , T3 and the diode D3. ΔPloss,3 = PT 2 + PT 3 + PD3. (4)
- 33. To estimatecomparative change in efficiency, η is identified as efficiency of the conventional buck or boost mode and η!is defined as the efficiency of the proposed converter with additional losses. If Po is the output power and Pin is the input power, the change in the efficiency can be obtained as Δη = η- η!= P0/PIN – P0/(PIN+P LOSS) (5) where IGBT’s VCE(SAT) is 1.6 V, whereas diode’s VF is 2.1 V Vdc → Vbatt boost mode, where the input voltage = 169.7 V, output voltage is 300 V, and the average input and output currents are 15.48 and 8.5 A
- 34. Therefore, thechange in efficiency for this mode can be expressed as = 0.9707 − 0.9452 = 2.55%. (6) When stepping-down the battery voltage,inVbatt →Vdc buck mode, input voltage is 300 V, output voltage is 169.7 V, and the input and output currents are 8.5 and 14.62A. Under these conditions, the change in efficiency can be calculated as
- 35. = 0.9729 −0.9462 = 2.67%. (7) For the rest of the operation modes, the analyses are the same, for 3 and 4 modes. Therefore, change in efficiencies in modes 1 and 2 are identical to that of modes 3 and 4.
- 36. COMPARATIVE ANALYSES OFTHE PROPOSED DC/DC CONVERTERS WITH CONVENTIONALAPPROACHES
- 37. Considering thesebuck and boost functionalities, the proposed converter reduces the number of dc/dc converters in all-electric vehicle. In order to provide the same functionality, four dc/dc converters would be needed, two of them would be boost dc/dc converters and other two of them would be buck dc/dc converters and four inductors are needed. The proposed converter adds only two more semiconductor devices,however it reduces the number of inductors from four to one as it is compared to the two buck and two boost converter’s approach. Inductors would require much more space as it is compared to the space requirement of two switches. Therefore, one can state that the proposed dc/dc converter would reduce both the cost and the size of the conventional approach for the same functionality basis.
- 38. SIMULATION OF DC-DCCONVERTER FOR BLDC MOTOR DRIVE-BOOST MODE
- 39.
- 40. LOAD VOLTAGE,TORQUE CHARACTERISTICSBOOST MODEOF BLDC MOTOR Current=1.5A,speed=3500rpm,torque=1N-m currentspeedtorque time
- 41. SIMULATION OF DC-DCCONVERTER FOR BLDC MOTOR DRIVE-BUCK MODE
- 42.
- 43. LOAD VOLTAGE,TORQUE CHARACTERISTICSOF BUCK MODE BLDC MOTOR Current=1.5A,speed=3800rpm,torque=1N-m currentspeedtorque time
- 44. SIMULINK DIAGRAM OFDC-DC CONVERTER FED SRM MOTOR DRIVE
- 45. COMPLETE SIMULINK DIAGRAMOF DC-DC CONVERTER FED SRM MOTOR DRIVE-BOOST MODE
- 46.
- 47. LOAD VOLTAGE,TORQUE CHARACTERISTICS OFSRM MOTOR Current= 10A,torque=1.5N-m ,speed=2200rpm currentspeedtorque time
- 48.
- 49. LOAD VOLTAGE,TORQUE CHARACTERISTICS OFSRM MOTOR Current= 10A,torque=1.5N-m ,speed=2200rpm currenttorquespeed time
- 51. PERFORMANCE CHARACTERISTICS OF SRMMOTOR AT FULL LOAD,SPEED=2200rpm currentspeedtorque time
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- 56. APPLICATIONS General purposeindustrial drives. Application-specific drives: compressors, fans, pumps, centrifuges. Domestic drives: food processors, washing machines, vacuum and cleaners. Electric vehicle application. Aircraft applications. Servo-drive.
- 57. ADVANTAGES High speedscan be obtained. SRM motor is not costlier as there rotor is not a permanent magnet. VRM is operated from unidirectional drive circuits,so cost is reduced. The noninverted operation capability of the proposed converter totally eliminates the need for an inverting transformer,which reduces the overall size and cost. Increases the flexibility.
- 58. CONCLUSION This studypresents a novel dc/dc converter structure that is suitable for both industrial needs and the retrofit electric vehicle conversion approaches. The proposed topology is suitable not only for conversion approaches but also is a good candidate to reduce the number of dc/dc converters from two to one in commercially available vehicles. By using SRM motor drive high speeds can be obtained and srm motor is not costlier.
- 59. FUTURE SCOPE Inthe future, a full-scale dc/dc converter will be built for a typical mid-size sedan vehicle and the converter will be implemented for a real-world application. Adjustable speed drive systems based on VRMs are becoming competitive with converter fed dc drives and inverter controlled induction motor drives.
- 61.
- 64. PARAMETERS OF SRMMOTOR DRIVE S.NO PARAMETER VALUE 1 TYPE 6/4 2 POWER 1.2KW 3 CURRENT 10A 4 VOLTAGE 160V 5 SPEED 6000RPM