Study of a Bidirectional Power Converter Integrated with Battery/Ultracapacitor Dual-Energy Storage

Abstract

A patented bidirectional power converter was studied as an interface to connect the DC-bus of driving inverter, battery energy storage (BES), and ultracapacitor (UC) to solve the problem that the driving motor damages the battery life during acceleration and deceleration in electric vehicles (EVs). The proposed concept was to adopt a multiport switch to control the power flow and achieve the different operating mode transitions for the better utilization of energy. In addition, in order to improve the conversion efficiency, the proposed converter used a coupled inductor and interleaved-pulse-width-modulation (IPWM) control to achieve a high voltage conversion ratio (i.e., bidirectional high step-up/down conversion characteristics). This study discussed the steady-state operation and characteristic analysis of the proposed converter. Finally, a 500 W power converter prototype with specifications of 72 V DC-bus, 24 V BES, and 48 V UC was built, and the feasibility was verified by simulation and experiment results. The highest efficiency points of the realized prototype were 97.4%, 95.5%, 97.2%, 97.1%, and 95.3% for the UC charge, battery charge, UC discharge, the dual-energy in series discharge, and battery discharge modes, respectively.

Simulation and Fault Diagnosis of Electric Vehicle DC/DC Converter Based on BP Neural Network

“…When the IGBT switches Q 1 and Q 4 are turned on and Q 2 and Q 3 are turned off, the power supply voltage forms a positive voltage square wave through Q 1 and Q 4 [6] , which is stepped down through the transformer, and then reaches the inductors Lf , The LC filter circuit formed by the capacitor C f filters and provides power for the load Rf, and then forms a loop through the diode D 8 , as shown in Figure 6. When the IGBT switches Q 2 and Q 3 are turned on and Q 1 and Q 4 are turned off, the power supply voltage forms a negative voltage square wave through Q 2 and Q 3 [7] , which is stepped down through the transformer, and then reaches the inductors Lf , The LC filter circuit formed by the capacitor C f performs filtering and provides power for the load Rf, and then forms a loop through the diode D 7 , as shown in Figure 7 .…”

Efficiency Enhancement of Non-Isolated DC-DC Interleaved Buck Converter for Renewable Energy Sources

“…In some cases, the interleaved mode can be implemented in novel topologies, or basic topologies with novel electrical components [4,5], and many other applications. For example, to enhance the output voltage ratio of boost converters [6][7][8], or for use in bidirectional connection [9,10], or for achieving better efficiency on passive components [11]. The interleaved connection finds its way in renewable energy sources [12][13][14], electrical vehicles [15], in isolated power sources [16,17], and many others.…”

Bidirectional Quadratic Converter-Based PMBLDC Motor Drive for LEV Application

“…e various nonisolated bidirectional DC-to-DC converters have been compared based on their performance [12,13]. e voltage gain of the converter is two times that of a conventional buck-boost converter.…”