Power Electronic Control Design for Stable EV Motor and Battery Operation during a Route

Abstract

Electric vehicles (EVs), during a route, should normally operate at the desired speed by effectively controlling the power that flows between their batteries and the electric motor/generator. To implement this task, in this paper, the voltage source AC/DC converter is considered as a controlled power interface between the electric machine and the output of the DC storage device; the DC/DC converter is used to automatically regulate the battery operating condition in accordance to the profile of the acting on the vehicle wheels, unknown external torque. Particularly, the speed is continuously regulated by the vehicle driver via the pedal while all other regulations for absorbing or regenerating energy are internally controlled. The driver command is acting as speed reference input on a PI outer-loop motor speed controller which, in its turn, drives a fast P inner-loop current controller operating in cascaded mode. In a similar manner, the machine and the battery performance are self-regulated by a pure PI current controller that achieves maximum electric torque per ampere operation of the motor and by a PI/P cascaded scheme for the DC-voltage/battery–current regulation, respectively. In order to exclude any possibility of instabilities and adverse impacts between the different parts, a rigorous analysis is deployed on the complete electromechanical system that involves the motor, the batteries, the converter dynamic models and the proposed controllers. Modeling the system in Euler–Lagrange nonlinear form and applying sequentially suitable Lyapunov techniques and the time-scale separation principle, a systematic method for tuning the gains of the inner- and outer-loop controllers is derived. Therefore, the proposed controller design procedure guarantees asymptotic stability by considering the accurate system model as a whole. Finally, the proposed approach is validated by simulating realistic route conditions, performed under unknown external torque variations.

A Comprehensive Review of Advanced Traction Motor Control Techniques Suitable for Electric Vehicle Applications

“…The various types of interconnections are illustrated by the key provided in the figure. The motor, vehicle controller, power electronic circuitry, power source and transmission, are the fundamental components of the system [6], [11]. The driver provides input to the system through the accelerator or brake pedal of the vehicle.…”

“…There are various power electronic circuitries that are contained in an electric vehicle, which includes DC/DC converters (utilised in battery charging and the DC/DC link between the battery system and motor control system), as well as the inverter circuitry in the motor control system [6], [11]. The power electronic circuitry should be designed to provide a fast and smooth response, controlled by both the driver control inputs, as well as automatic tracking, which controls the recharging and discharging of the batteries in the most efficient way [11]. Unidirectional or bidirectional DC/DC converters can be used in the battery charging system and the DC/DC link system between the batteries and the motor control system.…”

“…However, the use of bidirectional converters allows for vehicle-to-grid power flow as well as regenerative braking in the vehicle. Regenerative braking allows the batteries to be charged during the operation of the vehicle, which takes place mainly during braking and downhill travel [6], [11]. [17], [31], [33] Battery Type Advantages Disadvantages Lead-Acid…”

“…Furthermore, the use fossil fuels associated with ICEVs could see the depletion of non-renewable resources in the future [7], [9]. Consequently, EVs are currently a major consideration, and can aid in the reduction of greenhouse gas emissions, and the preservation of non-renewable resources [2], [8], [10], [11]. Such increasing attention and consideration have resulted in significant increases in the sale of battery electric vehicles (BEVs), with increased annual growth rates as high as 54-87% during 2012-2014 [12].…”

Gear Ratio Optimization along with a Novel Gearshift Scheduling Strategy for a Two-Speed Transmission System in Electric Vehicle

“…Characteristics of these types of electric motors are discussed in detail in the literature [20][21][22][23]. Interested readers are referred to [24][25][26] for in-depth knowledge on the control and modeling of electric motor for EVs. While some research can be found with more than one electric motor as the propulsion device in EVs [27,28], a single electric motor is considered in this study as the propulsion device.…”