Power Flow Control Strategy Based on the Voltage Vector Distribution for a Dual Power Electric Vehicle With an Open-End Winding Motor Drive System

A dual inverter feeding an open-end winding permanent magnet synchronous motor drive system can realize controllable power sharing or power flow between two independent power sources without a dc/dc converter. The two power sources can be selected among many options, such as fuel cells, engine generators, batteries, and supercapacitors. In this paper, the dual inverter's voltage vector distribution and power flow principles are discussed. Based on the analyses of the overlapping area of the two inverters' modulation ranges, the dual inverter's modulation capability is exploited sufficiently. A novel voltage vector distribution strategy is proposed based on a dual space vector pulse-width modulation control scheme, which is composed of four patterns using basic voltage vectors, single-saturated vectors, double-saturated vectors, and linear-saturated vectors, respectively. By selecting the most suitable pattern, the power-sharing demand can be met in its maximum range while the switching frequencies of the two inverters are lowered and well-balanced. Simulation results confirm the validity and the advantages of the proposed strategy and clarify the power-sharing range in the entire operating range of the motor. This system also provides a scheme for energy management in electric vehicle applications.