A Novel Pulse Density Modulation with Semi-bridgeless Active Rectifier in Inductive Power Transfer System for Rail Vehicle

In this paper,a novel pulse density modulation(PDM)with semi-bridgeless active rectifier(S-BAR)in inductive power transfer(IPT)system for rail vehicle is proposed.It is to reduce switching losses of the active rectifier in pickups.In the control method,the insulated-gate bipolar transistors(IGBTs)in the S-BAR are controlled by synchronous PDM signals,so that zero-voltage switching(ZVS)and zero-current switching(ZCS)can be achieved in the whole output power range.The output power is regulated by changing the pulse density(PD)of the S-BAR since the it is almost linear proportional with the PD in high quality factor of pickup side.The communication device between the primary side and pickup side is not necessary anymore.The detailed theoretical analyses of the PDM method are provided,and its advantages are shown in a 7.5kW IPT prototype for rail vehicle.The experimental results are presented to verify the analysis and demonstrate the performance.The overall efficiency of the system by PDM control is 74.2%which is improved by 4%compared with phase shift(PS)control at light load.

An ultra-low-voltage rectifier for PE energy harvesting applications

An ultra low voltage rectifier with high power conversion efficiency （PCE） for PE energy harvesting ap- plications is presented in this paper. This is achieved by utilizing the DTMOS which the body terminal is connected to the gate terminal in a diode connected transistor. This implementation facilitates the rectifier with dynamic con- trol over the threshold voltage. Moreover, we use input powered to take the place of output powered to reduce the power loss and thereby increasing the power conversion efficiency. Based on standard SMIC 0.18 μm CMOS tech- nology, the simulation results show that the voltage conversion efficiency and the power conversion efficiency can reach up to 90.5% and 95.5% respectively, when the input voltage equals to 0.2 V @ 100 Hz with load resistance 50 kW. Input voltages with frequencies in the range of 10 Hz-1 kHz can be rectified.