This paper proposes an interleaved LLC resonant converter with cascaded voltage doubler circuits for deeply depleted PEV battery charging. The use of voltage double circuits extends the operating range of converter by mitigating the effects of transformer’s parasitic capacitors. The converter has two modes of operation: simultaneous and independent. In former mode both interleaving converters operate together at same frequency and in later mode only one converter operates. In former mode, it yields twofold higher gain compared to later one. Thus, operation with combined mode changing and frequency control results in wider output voltage range. For confirmation, a laboratory prototype rated at input dc voltage of 400V and output power of 1.5kW is designed, and implemented. The results obtained from the prototype show that converter achieves a wide output voltage range of 100V–420V when operated in simultaneous mode with simple frequency control and an output voltage range of 50 –100V in the independent mode. With combined frequency and mode changing control it achieves an output range of 50V–420V. The peak efficiency of converter was measured to be 95.65% at a peak power of 1.5 kW. Thus, the proposed converter is suitable for the dc-dc stage of on-board PEV battery charger.

This paper proposes an HB-2LLC resonant converter with hybrid rectifier to realize wide output voltage control range (100-420 V) for plug-in electric vehicle (PEV), on-board battery charging. The converter has two resonant tanks, each connected with one of the two primary windings of transformer. The two resonant tanks are alternately fed from 400 V dc source by operating two power switches, each with a half switching cycle. The hybrid rectifier connected at the secondary of transformer can be operated as a bridge rectifier or voltage doubler. It operates as a bridge rectifier to achieve output voltage range of 100-250 V for deeply depleted battery charging, and as a voltage doubler to achieve output voltage range of 250-420 V for normal battery charging. To validate the operation and performance of converter, a laboratory prototype rated at 1.5 kW output power and 400 V input dc voltage was designed and implemented. The presented results show that with combined mode changing and frequency control, the converter achieves an output voltage range of 100-420 V. The peak efficiency of converter was measured to be 95.21% at a peak power of 1.5 kW. Thus, the proposed converter is suitable for PEV battery charging application.

Conventional pulse-frequency-modulated (PFM) zero-current switching series resonant (SR) inverter-fed voltage-multiplier-based high-voltage dc power supplies have nearly zero switching loss. However, they have limitations of poor controllability at light load and large output voltage ripple at low switching frequencies. To address these problems, this letter proposes a new control scheme that is based on digitally tuning tank capacitance and slightly varying pulse frequency of SR inverter. For the realization of the proposed control approach, the tank circuit of the resonant inverter is made up of several tank capacitors that are switched into or out of the tank circuit by electromechanical switches. By digitally modulating the tank capacitance, the output voltage changes in steps. The regulation of output voltage between two adjacent steps is achieved by slightly varying the pulse frequency. The proposed control scheme has several features, namely, a wide range of output voltage controllability even at light loads, less output voltage ripple, and less current stress on the inverter's power switches at light loads. Therefore, the proposed control approach alleviates most of the problems associated with conventional PFM. Experimental results obtained from a scaled-down laboratory prototype are presented to verify the effectiveness of the proposed system.

A voltage multiplier rectenna is a combination of a voltage multiplier rectifier and an antenna used for the conversion of AC to DC. It is an essential part of the system of RF energy harvesting. Conventional rectennas are characterized by low conversion efficiency. This study presents an analytical novel mode designed for RF energy harvesting systems to study the voltage and current output of rectifier stages for efficiency optimization. The design contains a voltage multiplier rectification circuit with seven stages. The Schottky diode HSMS 285-C was selected for the circuit modeling voltage multiplier circuit. Advanced Design System (ADS) simulation was used to validate the equations of the theoretical model solved with MATLAB code. The fabricated system was tested for an input power range of 10 μW to 100 mW; the maximum output power is 0.2577 mW with maximum efficiency of 29.85%.

Photovoltaic (PV) power is one of the promising solutions to address the fast-growing electricity demand. Electricity generated from the array of solar panels is not fixed due to the continuous change in environmental conditions. Therefore, an efficient power management system is required to facilitate the consumer with an uninterruptable power supply (UPS). When the energy demand is lower than the energy generated by the PV power system, the excessive energy must be stored in batteries and, when the energy demand is higher than the energy generated by the PV system, then the stored energy in the battery must be released in order to fulfil the load demand. Therefore, a bidirectional DC–DC converter is required to store and release energy. Conventional bidirectional converters offer low gain, low power density, low efficiency, high switching stress, and high magnitude of current and voltage ripples. In this paper, a bi-directional DC–DC converter that has low stress and low ripples is proposed for the operation of Stand-alone PV power systems. The proposed converter is implemented in ORCAD/PSPICE (Oregon Computer Aided Design/Personal Computer Simulation Program with Integrated Circuit) and both the charging and discharging modes have been analyzed explicitly. The results were compared with conventional converters and were found to be satisfactory. A significant improvement in the magnitude of output voltage and current ripples has been noticed. Besides, considerable improvement in switching stress (45% reduction as compared with conventional converters) and a 16.6% reduction in the magnitude of ripples was realized.