Research Of Compensating Low-Frequency Of Current With Bidirectional DC/DC Converter In Electric Vehicle

With the deepening of energy crisis,electric vehicle is constantly used as a means of energy conservation and emission reduction.In the electric vehicle charger,AC/DC converter usually use the PWM rectifier.It can adjustable power factor,bidirectional power transfer,reduce current harmonic distortion and improve the efficiency of the charger.But the PWM rectifier lead to second-order ripple voltage on DC-link.The power pulsating is generally eliminated by a bulk capacitor which results in low power density.In this paper,it will analysis the low frequency ripple on the DC side.Firstly,it will present a new charging structure for electric vehicles with hybrid energy storage system.Compared with the traditional electric vehicles charger,thus reducing the a bidirectional DC/DC application stage.Analysis the topology and working principle in bidirectional DC/DC converter.It set up mathematical model of PWM rectifier.Using double closed loop control strategy for AC/DC converter,analysis power factor and circuit performance by simulation.Secondly,for low frequency ripple on the PWM rectifier DC side,design the buck type compensation circuit.Researcd low frequency ripple compensation case.Simulation results are compared and analyzed.The system has the high power density.Finally,for the low-frequency component of the battery load current,propose a new load current compensation technique.PWM rectifier load current on DC side is analyzed in detail.It injects?180 phase-shifted second harmonic current to the dc link by the capacitor.Analysis the energy balance controller,storage capacitor,power of DC/DC converter.The effect of the compensation method is validated by simulation,reduces the cost of the system.