Page 23 - IJOCTA-15-4

Control strategies and power converter topologies for switched reluctance motors in electric...
No. of No. of diodes
Type of switches and
Topology per capacitors Advantages Disadvantages
phase per phase
• Large voltage
variation
• No zero-voltage
state during
conduction
• The additional resistive
damping element can
• Fewer power increase overall losses,
switches reducing system efficiency
• Simple structure and • Incorporating the
low cost R-dump winding requires
• Reduced torque a more complex design
ripple and integration with
• Improved efficiency the motor
• Better control of • The added resistance
R-dump (Figure 23B) 2 2, 1 phase currents can cause higher local
• Lower electromagnetic heating, increasing
interference thermal management
• Improve the fault challenges
tolerance of the • May not be
motor system suitable for
• Reduced mechanical high-power
stress due to • The damping
the damping action resistance may reduce
the overall power
density
• Potential for
voltage stress
• Slower
response due to
damping
• Improved voltage • Complex control needs
balancing, reducing sophisticated algorithms
the risk of • Capacitor voltage
overvoltage ripple requires
• Reduce harmonics additional control
leading to • Higher component
smoother operation count
Flying capacitor (Figure 24A) 4 4, 2
• Better efficiency • Additional capacitors
• Compact design increase the
reduced stress overall cost
on switches • Lower power density
• Enhanced regenerative • Multiple capacitors
capability increase the size and
• Higher reliability weight
• Low efficiency
• Independent phase • Energy recovery circuit
control losses
• Fewer power • Higher voltage
switches stress
• Improved torque • Limited scalability
C-dump (Figure 24B) 2 2, 1 ripple control • Energy loss in
• Simpler structure dumping the
• Cost-effective capacitor
• Support for • Reduced fault
regenerative braking tolerance
• Reliable operation • Thermal management
challenges

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