Page 97 - IJEEE-2022-Vol18-ISSUE-1

Received: 21 February 2022 Revised: 23 March 2022 Accepted: 24 March 2022
DOI: 10.37917/ijeee.18.1.11
Vol. 18| Issue 1| June 2022
? Open Access

Iraqi Journal for Electrical and Electronic Engineering

Original Article

Building A Control Unit of A Series-Parallel Hybrid
Electric Vehicle by Using A Nonlinear Model
Predictive Control (NMPC) Strategy

Maher Al-Flehawee *, Auday Al-Mayyahi
Department of Electrical Engineering, College of Engineering, University of Basrah, Basrah, Iraq

Correspondence
* Maher Al-Flehawee
Electrical Engineering Department
College of Engineering,
University of Basrah, Basrah, Iraq
Email: eng23mm@gmail.com

Abstract
Hybrid electric vehicles have received considerable attention because of their ability to improve fuel consumption compared to
conventional vehicles. In this paper, a series-parallel hybrid electric vehicle is used because they combine the advantages of the
other two configurations. In this paper, the control unit for a series-parallel hybrid electric vehicle is implemented using a
Nonlinear Model Predictive Control (NMPC) strategy. The NMPC strategy needs to create a vehicle energy management
optimization problem, which consists of the cost function and its constraints. The cost function describes the required control
objectives, which are to improve fuel consumption and obtain a good dynamic response to the required speed while maintaining
a stable value of the state of charge (SOC) for batteries. While the cost function is subject to the physical constraints and the
mathematical prediction model that evaluate vehicle's behavior based on the current vehicle measurements. The optimization
problem is solved at each sampling step using the (SQP) algorithm to obtain the optimum operating points of the vehicle's
energy converters, which are represented by the torque of the vehicle components.
KEYWORDS: Series-Parallel Hybrid Electric Vehicle (HEV), Nonlinear Model Predictive Control (NMPC), Planetary Gear
Set (PGS), Energy Management Strategies (EMS), state of the charge (SOC).

I. INTRODUCTION Fig.1: The powertrain and vehicle dynamic block
While the energy is transmitted through the electrical
The series-parallel hybrid electric vehicle can operate path from the engine to the Planetary Gear Set (PGS) by the
either in series or parallel power flow mode due to the carrier gear and then transmitted to the MG1 after passing
presence of a planetary gear set (PGS) that separates the through the sun gear, and then transferred as electrical energy
power generated by the engine into mechanical and electrical to be stored in the on-board battery or used to feed the MG2
paths [1]. The planetary gear set consists of three nodes [3].
called the ring gear, the sun gear, and the carrier gear where The series-parallel hybrid electric vehicle's control units
these nodes are connected directly to the engine (ICE), that control the operation of the vehicle are based on one of
generator (MG1), and the vehicle's body respectively. While the various energy management strategies (EMS)[4][5][6].
the motor (MG2) is also connected to a ring gear, which acts This strategy is responsible for managing the vehicle’s
as a traction motor to propel the vehicle [2]. It also works as energy represented by liquid fuel and batteries, in addition to
a generator to capture the kinetic energy resulting from the
deceleration of the vehicle or when applying the brakes or
when descending from a slope and this is called regenerative
braking. Fig.1 shows the elements and connections of the
planetary gear set and the configuration of the powertrain of
the series-parallel hybrid electric vehicle.

As the energy is transmitted through the mechanical path
from the engine to the planetary gear set (PGS) by the carrier
gear and then it is transferred directly to the ring gear and
reaches the vehicle after the energy passes through the
reduction gear which connects the ring gear with the vehicle.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and
reproduction in any medium, provided the original work is properly cited.
© 2022 The Authors. Iraqi Journal for Electrical and Electronic Engineering by College of Engineering, University of Basrah.

https://doi.org/10.37917/ijeee.18.1.11 https://www.ijeee.edu.iq 93