Search This Blog

Friday, 19 February 2016

Torque Hysteresis Control of BLDC Drives for EV Application by using fuzzy logic controller

With ever increasing oil prices and concerns for the natural environment, there is a fast growing interest in electric vehicles (EVs). However, energy storage is the weak point of the EVs that delays their progress. For this reason, a need arises to build more efficient, light weight, and compact electric propulsion systems, so as to maximize driving range per charge. There are basically two ways to achieve high power density and high efficiency drives. The first technique is to employ high-speed motors, so that motor volume and weight are greatly reduced for the same rated output power. Most adjustable speed drive systems employ a single three-phase induction motor. With such a drive system, the drive has to be shut down if any phase fails. In order to improve reliability of drive systems, six-phase induction motors fed by double current source inverters have been introduced. Such a drive requires a specially wound multiphase motor but enables the motor to continue to operate at failure of any single drive unit, although it does degrade motor performance. Compared to induction motors, permanent magnet (PM) motors have higher efficiency due to the elimination of magnetizing current and copper loss in the rotor. It has become possible because of their superior performance in terms of high efficiency, fast response, weight, precise and accurate control, high reliability, maintenance free operation, brushless construction and reduced size. This project presents a current blocking strategy of brushless DC (BLDC) motor drive to prolong the capacity voltage of batteries per charge in electric vehicle applications. The BLDC motor employs a fuzzy controller for torque hysteresis control (THC) that can offer a robust control and quick torque dynamic performance. The proposed concept is verified by using Matlab/Simulink software and the corresponding results are presented.

1.      Components
2.       Brushless DC motor
3.       Hall effect
4.       Current controller
5.       Electric vehicle (EV)
6.       Hybrid electric vehicle (HEV)
7.       Torque hysteresis controller (THC)
8.      Fuzzy logic controller


Fig 1. Structure of Optimal Current Control drive for BLDC motor.



Fig 2.proposed blocking strategy based on hysteresis comparator.


Fig 3. Motor currents are controlled such that follow their references which are generated according to the hall effect signals (Time/div=0.5s/div).

Waveform of current and emf

Waveform of speed

Waveform 0f torque
Fig 4 (a) THC without current blocking strategy

Waveform of current and emf

Waveform of speed

Waveform of torque
Fig 5.(b) THC with current blocking strategy.


This project presented the modelling and experimental result of THC for BLDC motor. The current controller has been applied to a BLDC drive and the results shows that the current ripple stays within the hysteresis band as defined by the controller. The proposed current blocking strategy shows that the energy wastage from the batteries is prevented such that it can prolong the capacity of voltage battery and it also showed that the hysteresis controller by using fuzzy logic controller can offer inherent current protection/limitation and robustness in controlling the motor torque.


[1] Lefley, P., L. Petkovska, and G. Cvetkovski. Optimization of the design parameters of an asymmetric brushless DC motor for cogging torque minimization in Power Electronics and Applications (EPE 2011), Proceeding of the 2011-14th European Conference on 2011.
[2] Bahari N., Jidin A., Abdullah A. R. and Othman M. N., “Modeling and Simulation of Torque Hysteresis Controller for Brushless DC Motor Drives”, IEEE Symposium on Industrial Electronics and Applications ISIEA, 2012.
[3] Mayer, J.S. and O. Wasynczuk, “Analysis and modelling of a single-phase brushless DC motor drive system”, Energy
[4] Jidin, A., Idris, N. R. N., Yatim, A. H. M., Sutikno, T. and Elbuluk, M. E. „An Optimized Switching Strategy for Quick Dynamic Torque Control in DTC-Hysteresis-Based Induction Machines‟, IEEE Transactions on Industrial Electronics,2011, Vol. 58, pp. 3391-3400.

[5] Norhazilina Binti Bahari; Jidin, Auzani bin; Abdullah, Abdul Rahim bin; Md Nazri bin Othman; Manap, Mustafa bin, "Modeling and simulation of torque hysteresis controller for brushless DC motor drives," Industrial Electronics and Applications (ISIEA), 2012 IEEE Symposium on , vol., no., pp.152,155, 23-26 Sept. 2012