Vector-Control System of Permanent-Magnet Synchronous Motor Drives for Electric Vehicles

Abstract

1990's. Electric vehicles can reduce air pollution. Further, the upcoming shortage of gasoline products and the expected reduction of EVs' cost have encouraged people to look at them as a possible way of transportation. Other reasons are the tremendous progress in power electronics, motor topologies and microelectronics industries through the last few years. So, the next decade is considered to be the decade of producing an economic, safe, comfortable and high performance electric vehicle.

The objective of this study is to select the most suitable and reliable electric machine to be used for such application. Hence, the design and implementation of the control system for the selected machine is the second , but of the same importance , task. It is concluded after a detailed study that the permanent magnet synchronous motor (PMSM) will be an economic solution. It has many advantages e.g. high efficiency, silent operation, wide speed range and high flexibility. This makes it a superior choice compared to the other motors in the electric vehicle application. Vector Control is normally applied to AC machines. The application of vector control to the PMSM and its drive system is given in this work. It fulfills the high­ performance demands, robustness and independence as well.

In this study, the mam features and characteristics of the PMSM are included. Different control system drives are also presented. The modeling of the PMSM is developed and analyzed in different reference frames. The derived model is utilized in the simulation study for many PMSM drives. This will give an excellent view of the PMSM performance under vanous operating conditions. The design and implementation of the DC-link inverter including required circuitry IS presented. The Intelligent power module (/PM) is utilized. It consists of six IGBT's and supports a very advanced technology that could detect and overcome many operating obstacles. It has an inherent protection circuits against short circuit current, over current, over

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temperature and under voltage. Once a fault is detected, a fault output signal is initiated. Then, a complete isolation between the power side and control side is achieved. The whole system is forced to the shut down mode

In addition, a simplified space vector PWM modulator is deduced This technique provides the simplest way for obtaining the control pulses of the inverter in comparison with the conventional space vector method. The vector controller has been achieved using the derived method through the 80CJ96KC micro-controller. The interfacing circuits for the shaft encoder

and the current transducers have been implemented. Further, the current regulator is developed in the stationary reference frame. The control program is implemented by the assembly language of the 80Cl96KC micro-controller It provides an on-line control of the PMSM drive. Finally, the developed control system ts verified experimentally. The experimental results are gtven and recorded at different operating conditions for all control stages to examine the validity of the drive system. Also, it shows good agreement with the theoretical results. In conclusion, the thesis shows the following . (1) It confirms that the PMSM will strongly compete the other machines in the near future for electric vehicle application This could be attributed to the great advantages of PMSM over them. (2) A simplified space vector modulator is introduced. It reduces the computational burden and minimizes the size of the developed control program. This will play a great role in enhancing the overall performance of the PMSM drive. (3) Application of an advanced inverter module. It consists of six IGBT's which

are supported with many built in protection circuits.

(4) The developed PMSM drive is flexible enough to be adapted for different ratings with a very slight modification. In addition , it could be utilized for different applications