Analysis of power factor correction converters

ABSTRACT Power Converterwith capacitive input filter is a non-linear load to the Utility AC power lines. There are widely used as Switch-Mode Power Supplies in office equipment applications ranging from Personal Computers to Office Printers and Copiers. The distorted input currentwaveform extracted by the capacitive input filter of the power converters produces unwanted harmonicswhich propagates to other line powered equipments. The harmonic pollutes the AC lines and interferes with the operations of sensitive line powered equipments. The distorted current waveform also leads to inefficient utilization of the available power from the AC outlet. This is because the AC line power is transferred to the load onlywhen each frequency component of the line voltage is an in-phase, scaler related quantity with respect to the same frequency component of the extracted current. The problems of poor power factor and harmonic distortion are compounded by the proliferation of Switch-Mode power supplies and the situation is rapidly becoming intolerable. The problem of poor quality input currentwaveform can be described by two quantitativemeasurements: Power Factor (pf) and Total Harmonic Distortion (thd). Two general approaches are available to remedy the problem. One approach is to install passive filter networks between the Utility AC lines and the capacitive input filter. The second approach is to design active power processors as dedicated Power Factor Correction (pfc) Converters and installed as the front end to the capacitive input filter to shape the distorted current waveform intowaveforms which will yield higher power factor. This Thesis first introduce the general concept of PF and harmonic distortion in Chapter 1 . Chapter 2 derive the mathematical description of pf based on the concept of real power (pR) and apparent power {pA). Both sinusoidal and nonsinusoidal cases are studied. For comparison and completeness, two popular passive power factor correction filter networks are analyzed in Chapter 3 to derive the maximum achievable power factor for each network along with the corresponding harmonic distortions. Governing equations are derived and presented graphically as a function of the filter network and load parameters. Chapter 4 provides the analysis of active power factor correction using switch mode Boost Converter. The analysis is carried out for two types of current controllers used as the current modulators forPower Converterwith capacitive input filter is a non-linear load to the Utility AC power lines. There are widely used as Switch-Mode Power Supplies in office equipment applications ranging from Personal Computers to Office Printers and Copiers. The distorted input currentwaveform extracted by the capacitive input filter of the power converters produces unwanted harmonicswhich propagates to other line powered equipments. The harmonic pollutes the AC lines and interferes with the operations of sensitive line powered equipments. The distorted current waveform also leads to inefficient utilization of the available power from the AC outlet. This is because the AC line power is transferred to the load onlywhen each frequency component of the line voltage is an in-phase, scaler related quantity with respect to the same frequency component of the extracted current. The problems of poor power factor and harmonic distortion are compounded by the proliferation of Switch-Mode power supplies and the situation is rapidly becoming intolerable. The problem of poor quality input currentwaveform can be described by two quantitativemeasurements: Power Factor (pf) and Total Harmonic Distortion (thd). Two general approaches are available to remedy the problem. One approach is to install passive filter networks between the Utility AC lines and the capacitive input filter. The second approach is to design active power processors as dedicated Power Factor Correction (pfc) Converters and installed as the front end to the capacitive input filter to shape the distorted current waveform intowaveforms which will yield higher power factor. This Thesis first introduce the general concept of PF and harmonic distortion in Chapter 1 . Chapter 2 derive the mathematical description of pf based on the concept of real power (pR) and apparent power {pA). Both sinusoidal and nonsinusoidal cases are studied. For comparison and completeness, two popular passive power factor correction filter networks are analyzed in Chapter 3 to derive the maximum achievable power factor for each network along with the corresponding harmonic distortions. Governing equations are derived and presented graphically as a function of the filter network and load parameters. Chapter 4 provides the analysis of active power factor correction using switch mode Boost Converter. The analysis is carried out for two types of current controllers used as the current modulators for