Michael J. Willers

Power-Factor-Corrected Single-Stage Inductive Charger for Electric Vehicle Batteries

A novel power-factor-corrected single-stage alternating current/direct current converter for inductive charging of electric vehicle batteries is introduced. The resonant converter uses the current-source characteristic of the series-parallel topology to provide power-factor correction over a wide output power range from zero to full load. Some design guidelines for this converter are outlined. An approximate small-signal model of the converter is also presented. Experimental results verify the operation of the new converter

A BIFRED converter with a wide load range

In this paper, the boost integrated flyback rectifier energy DC-DC (BIFRED) power converter which incorporates power factor correction, output voltage hold-up and input-to-output isolation is examined. The particular problem of high bulk capacitor voltage at light loads is addressed and it is shown how this may be resolved if the boost and flyback sections of the power converter are allowed to operate discontinuously. The criteria for ensuring correct operation in the discontinuous mode are investigated. It is shown that operating in this mode places no restrictions on the minimum load and simplifies the control loop design.<<ETX>>

A Family of Single-Stage Resonant AC/DC Converters With PFC

A family of novel, single-stage, isolated, resonant-based AC/DC power supply circuits with inherently high power factor is presented in this paper. The three topologies in the family are transformer isolated; they contain a bulk energy storage capacitor to enable output voltage holdup, and they also contain a resonant circuit in which a resonant capacitor is connected directly across the mains input rectifier. The presence of this resonant circuit results in AC line current being drawn over much of the line cycle, as well as in soft switching of the power devices. The rectifier-compensated fundamental-mode approximation (RCFMA) method is used to provide an accurate yet simple analysis of the circuit. Experimental results for closed-loop operation of two of the topologies are also presented. This family of single-stage, high-power-factor converters provides for simple control and high-frequency operation, due to the resonant configuration of the power circuit, without the excessive conduction loss of fully resonant techniques.

Analysis and design of a practical discontinuous-conduction-mode BIFRED converter

Impending international standards on harmonic current levels drawn by single-phase mains-operated equipment have created a need for low-cost off-line power-factor-corrected switched-mode power supply topologies in the power range up to a few hundred watts. The boost integrated/flyback rectifier/energy storage/DC-DC converter (BIFRED) is one such topology which shows promise in this regard. In particular, the discontinuous-conduction-mode (DCM) BIFRED avoids the light-load high-voltage stress problem associated with the continuous-conduction-mode design, while still achieving the combined advantages of a low-cost single-stage topology with high displacement factor and low total harmonic distortion. In this paper, a practical DCM BIFRED converter with integrated low-loss snubber is investigated from both power and small-signal control perspectives. Design equations are given to ensure DCM operation under closed-loop output voltage control, in which switch duty cycle is varying. Experimental results on a prototype converter are also presented.

Analysis and design of a new three-phase LCC-type resonant DC-DC converter with capacitor output filter

This paper presents a new topology for DC/DC power conversion based on a three-phase LCC-type resonant circuit with a capacitive output filter. A simple, yet accurate, analysis and a practical, step-by-step design procedure are presented. Advantages include soft-switching for all of the inverter switches, narrow control frequency range and high-power capability with high-frequency operation for high-voltage applications.

A new resonant single-stage PFC converter suitable for high-current low-voltage applications

A single-stage, isolated, LCC resonant based AC/DC power converter incorporating power factor correction (PFC) and output voltage holdup is proposed. The operation of the resonant circuit enables a narrow switching frequency range and ZVS operation down to no-load. An LC output filter renders it suitable for low voltage, high current applications. The rectifier compensated fundamental mode approximation (RCFMA) method is used to provide an accurate yet simple analysis of the circuit. Initial results from a 3.3 V, 30 A prototype are presented.