Advanced high-frequency electronic ballasting techniques for gas discharge lamps

Small size, light weight, high efficacy, longer lifetime and controllable output are the main advantages of high-frequency electronic ballasts for gas discharge lamps. However, power line quality and electromagnetic interference (EMI) issues arise when a simple peak rectifying circuit is used. To suppress harmonic currents and improve power factor, input-current-shaping (ICS) or power-factor-correction (PFC) techniques are necessary.; This dissertation addresses advanced high-frequency electronic ballasting techniques for gas discharge lamps by using a single-stage PFC approach. The proposed techniques include single-stage boost-derived PFC electronic ballasts with voltage-divider-rectifier front ends, single-stage PFC electronic ballasts with wide range dimming controls, single-stage charge-pump PFC electronic ballasts with lamp voltage feedback, and self-oscillating single-stage PFC electronic ballasts.; Single-stage boost-derived PFC electronic ballasts with voltage-divider-rectifier front ends are first developed to solve the problem imposed by the high boost conversion ratio required by commonly used single-stage discontinuous conduction mode (DCM) boost-derived PFC electronic ballast. Two circuit implementations, which are the single-stage critical-conduction-mode PFC electronic ballast and the single-stage interleaved PFC electronic ballast, are proposed, analyzed and their performances are verified by experimental results.; Although the bus voltage stress at normal lighting can be reduced to the line peak voltage using the proposed voltage-divider-rectifier concept, extremely high bus voltage stress still exists during dimming operation due to the interaction between the PFC stage and the inverter stage. To reduce the bus voltage and achieve a wide range of dimming control, a novel single-stage PFC electronic ballast with asymmetrical duty-ratio control is proposed. The proposed circuit integrates the DCM boost PFC stage with a novel asymmetrical duty-ratio controlled inverter, which results from the integration of resonant inverter with the quasi-square-wave (QSW) DC/DC converter, so that the bus voltage is suppressed by duty-ratio control. ZVS operation of MOSFETs is retained by the proper design of DC/DC inductance. Experimental results show that striations are eliminated by asymmetrical operation, and wide stable dimming operation is achieved with constant switching frequency.; Single-stage charge-pump (CP) PFC techniques utilize a high-frequency current source (CS) or voltage source (VS) or both to charge and discharge the so-called charge-pump capacitor in order to achieve PFC. The bulky DCM boost inductor is eliminated so that this family of PFC circuits has the potential for low cost and small size. Five known CPPFC electronic ballasts, namely the basic CS-CPPFC, the basic VS-CPPFC, the VS-CPPFC with improved crest factor (ICF), the basic VSCS-CPPFC and the VSCS-CPPFC with ICF electronic ballasts, are investigated. A novel VSCS-CPPFC electronic ballast with lamp voltage feedback is proposed to reduce the bus voltage stress at light-load operation. This family of single-stage PFC electronic ballasts are implemented and evaluated, and then are verified by experimental results.; To further reduce the cost and size, a self-oscillating technique is applied to the single-stage CPPFC electronic ballast. Novel winding voltage modulation and current injection concepts are proposed to modulate the switching frequency so that lamp crest factor (CF) and power variations are improved. Circuit topology and experimental results show that the self-oscillating single-stage CS-CPPFC electronic ballast with current injection offers a more cost-effective solution for non-dimming electronic ballast applications.