Kasrul Abdul Karim

Improved performance of DTC of five-phase induction machines

The paper describes about optimal voltage vector selection for high-performance of Direct Torque Control (DTC) of five-phase induction machine. The decoupled control of stator flux and electromagnetic torque based on hysteresis controllers as employed in conventional DTC is applied to retain the simplicity and to provide quick instantaneous control. A look-up table that selects the most optimal voltage vectors according to the speed operations, i.e. low-speed, middle-speed and high-speed is proposed to improve DTC performances such as excellent torque dynamic control, minimization of torque ripple, high-efficiency (due to lower switching frequency) and extension of constant torque region. All the improvements are validated through simulation results.

Improved performance of DTC for 5-phase induction machine using open-end topology

In this paper, the advantage of using open-end inverter topology which can provide greater number of vector selection in minimizing the output torque ripple of Direct Torque Control (DTC) of 5-phase induction machine was proposed. By employing Dual Inverter Fed Open-End winding topology, it provides 132 effective voltage vectors where each vector may give different effect on controlling performance of 5-phase induction machine in various torque demand. The de-coupled control of stator flux and output torque based hysteresis band controller which implemented in conventional DTC system is applied to retain the simplicity of this system. It can be shown that the selection of the proposed voltage vector using open-end topology can produce better DTC performance in terms of torque ripple and quality of output voltage waveform.

A dual mode DTC of open-end winding induction motor drive with reduced torque ripple

In this paper, a new control strategy for Direct Torque Control (DTC) of dual two-level VSI fed 3-phase induction motor drive in an open end winding configuration is presented. The drive can be operated in dual mode; open-end winding or conventional single-sided supply configuration; based on the condition of the motor speed. A block of Optimum Status Detection & Mode Selector (OSD & MS) is introduced to the original structure of the DTC in order to analyze the motor speed condition and also to monitor the torque operating condition. Based on the information from the block, a new lookup table is devised for selecting of the most optimum voltage vectors. Since the open-end winding providing greater numbers of voltage vector, its have the capability to minimize torque ripple. A simulation has been conducted using MATLAB/Simulink in order to achieve the results.

Optimal torque control performance of DTC of 5-phase induction machine

In this paper, optimal voltage vector selection for high-performance of Direct Torque Control (DTC) of five-phase induction machine is presented. The de-coupled control of stator flux and electromagnetic torque based on hysteresis controllers as employed in conventional DTC is applied to retain the simplicity and to provide quick instantaneous control. A single complete look-up table that selects the most optimal voltage vectors according to the motor operating condition is proposed. This improves DTC performances such as excellent torque dynamic control, minimization of torque ripple, high-efficiency (due to lower switching frequency) and extension of constant torque region. All the improvements are validated through simulation results.

Improvement of power density spoke type Permanent Magnet Generator

This paper discusses on the improvement of power density of hollow rotor compared to conventional spoke type Permanent Magnet Generator (PMG). The objective of this research is to propose a rotor structure that could improve the power density by maximizing the flux linkage of the machine. In this research the Finite Element Analysis (FEA) is used to simulate the characteristics of the hollow rotor spoke type PMG at various speed. The result shows that the hollow-rotor topology has higher back electromagnetive force and output voltage compared to conventional spoke type PMG. In addition, the hollow-rotor spoke type motor has higher output power compared to conventional spoke type PMG. In summary, this paper provides an overview of the performance of the hollow-rotor spoke type topology that contributes high power density.

Electric Vehicle Development and Prediction of Battery Consumption Based on a Journey Profile

The lack of internal combustion engine (ICE) for electric vehicle (EV) makes it solely dependable on battery supply. Due to this, the prediction of battery consumption becomes crucial to determine the accurate driving range before the car needs to be re-charged. The developed prediction model can also be applied as simulation tool and help in reducing the length and the cost of the EV design process. This paper presents the prediction of battery power requirement for a small re-engineered EV converted from a commercial ICE car by using vehicle dynamic mathematical equations. The prediction is performed based on multiple journey profile that gathered before the actual test. The development of re-engineered EV is also presented, along with the experimental result of an actual drive test on a racing circuit to validate the prediction model.

An Analysis of Virtual Direct Power Control of Three-Phase AC-DC Converter

This paper describes the method to control a hybrid robot whose main task is to climb a pole to place an object on the top of the pole. The hybrid pole-climbing robot considered in this paper uses 2 Planetary PG36 DC-motors as actuators and an external rotary encoder sensor to provide a feedback on the change in robot orientation during the climbing movement. The orientation control of the pole-climbing robot using self-tuning method has been realized by identifying the transfer function of the actuator system under consideration, being followed with the calculation of control parameters using the self-tuning pole-placement method, and furthermore being implemented on the external rotary encoder sensor. Self-tuning pole-placement method has been explored to control the parameters q 0 , q 1 , q 2 , and p 1 of the controller. The experiments were done on a movement path in a form of a cylindrical pole. The first experiment was done based one the change in rotation angle of the rotary sensor with the angle values greater than 50˚ in the positive direction, whereas the second experiment was done with the angle values greater than -50˚ in the negative direction. The experiment results show that the control of the robot under consideration could maintain its original position at the time of angle change disturbance and that the robot could climb in a straight direction within the specified tolerance of orientation angle change.

DTC brushless DC motor by using constant switching frequency

This paper propose direct torque control of constant switching frequency for brushless dc motor DTC-CSF BLDC. It is due to overcome the drawback of conventional DTC such as high torque ripples and variable switching frequency. It is applied by using PI controller to regulate the error of torque producing output error of PI controller, and then compare it with carrier or triangular frequency to generate constant switching frequency. The experiment is implemented by using Altera field-programmable gate array (FPGA) and digital signal processor. Results of experiment show the torque ripples waveforms are maintained in each level of speed and constant switching frequency is proved by the existence of fundamental frequency of 3125 Hz where it is clearly appeared in the frequency spectrum in any variation speed level.

Investigation of torque and flux-current producing components in indirect rotor flux oriented control (IRFOC) of induction machines

This paper presents an investigation of torque and flux-current producing components in indirect rotor flux oriented control (IRFOC) of induction machine. Induction machine faced the problems when the motor rotates at the highest speed due to complex mathematical model based on the previous research. Therefore, to prove that there have the coupling effect, the investigation towards the torque and flux current component of IRFOC is done. The method that have been used to detect the problem is by using simulation method on MATLAB software. The algorithm and controller that been used is Field Oriented Control (FOC) because it is the first method in drive system that are been used in order to solve the induction machine problems. Simulation results presented in this paper show the torque, rotor flux, direct and quadrant current component when varying the value of torque and flux.

Constant switching frequency for Direct Torque Control of induction motor

DTC drives utilizing hysteresis comparator is one of the simplest and most popular technique used in induction drives. However, due to its disadvantage of variable switching frequency causes serious problem in DTC especially for electromagnetic torque ripple. This paper proposed a technique of constant switching that could reduce the ripple on both torque and phase current for DTC by using triangular waveform or carrier frequency. Thus, the conventional and proposed DTC will be simulated and demonstrated by using Altera field-programmable gate array (FPGA) and digital signal processor. Simulation results presented in this paper shows the torque and stator current ripple with the proposed DTC algorithm when varying the speed and the carrier frequency.