Power electronics phase control rectifier
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The document discusses phase control rectifiers and their operating principles. It covers topics like single phase half wave control with resistive and RL loads, including the use of a freewheeling diode. It discusses various performance parameters like average output voltage, power factor, current distortion factor, rectification ratio and more. It also covers single phase half wave control with RLE loads and full wave controlled converters using midpoint and bridge configurations.
Power electronics phase control rectifier
- 1. Power Electronics Phase Control Rectifier Kumar goswami M.TECH(Power electronics) B.E.(electrical engg.) Rcet bhilai
- 2. Principle of Phase Control Single phase Half wave Control with R load
- 3. Waveforms
- 4. Performance Parameters • Average O/P Voltage The maximum value of output voltage occurs at α = 0° , Vom = (Vm/2ᴨ).2 = Vm/ᴨ
- 5. Continued…. • Average Load Current , • RMS value of load voltage (For electric heating and incandescent lamps)
- 6. Continued…. • Power delivered to Resistive Load = (RMS load voltage x RMS load current) • Input Volt Amperes = (rms source voltage x total rms line current) = Vs . Ior • Input power factor = Power delivered to load/Input VA = (Vor.Ior)/(Vs.Ior) = (Vor/Vs) • Input displacement factor (DF) or fundamental power factor = cos (angle between supply voltage and current) • Input current distortion factor (CDF) – Ratio of rms value of fundamental component Is1 of the input current to rms value of input = Is1/Is
- 7. Continued…. • Rectification ratio : ratio of DC output power to AC output power Also known as rectification efficiency or figure of merit . In case forward resistance Rd then
- 8. Continued…. • Form Factor (FF) – Ratio of rms value Vor of output voltage to the dc value of Vo FF is a measure of shape of output voltage. Close to unity, better dc output voltage waveform
- 9. Continued…. • Voltage Ripple Factor (VRF) : Ratio of ripple voltage to the average output voltage. Effective or, Ripple value of the ac component of output voltage is given by
- 10. Continued…. • Transformer Utilization Factor (TUF) : Rms secondary voltage and current or, transformer VA rating
- 11. Single phase Half wave Control with R-L load
- 12. Continued….
- 13. Continued….
- 14. Single phase Half wave Control with R-L load & Free Wheeling Diode
- 15. Continued….
- 16. Continued…. • Freewheeling diode, by pass or commutating diode • Two modes are : Conduction mode Free wheeling mode
- 17. Continued…. • Input pf is improved (power delivered to load in both modes / Input KVA) • Load current waveform is improved • From above, load performance is better • As energy stored in L transferred to R during the freewheeling period, overall converter efficiency increases. • Supply current is unidirectional in both cases (dc pulses) introduces dc component to supply line. This is undesirable as as it leads to saturation of supply transformer and harmonics etc
- 18. Continued….
- 19. Single phase Half wave Control with R-L-E load
- 20. Continued….
- 21. Continued…. • Firing angle lies :
- 22. Full wave Controlled Converters • SCR controlled converters (or rectifiers) Classification: According to No of supply phases to input According to No of load current pulses during one cycle of source voltage
- 23. Continued….
- 24. Continued….
- 25. Single Phase Full wave Converters • Single Phase Full wave mid point converter (M-2 connection) • Single Phase Full wave Bridge converter (B-2 connection)
- 26. Single Phase Full wave mid point converter (M-2 connection)
- 27. Waveforms
- 28. Single Phase Full wave Bridge Converter (B-2 connection)
- 29. Waveforms