Ahmad Shukri Abu Hasim

A New Single-Phase Controlled Rectifier Using Single-Phase Matrix Converter

This paper presents the applications of single-phase matrix converter (SPMC) as an AC-DC controlled rectifier. For basic operation the multiple-PWM technique was used to calculate the switch duty ratio to synthesize the output. Safe commutation strategy was developed to avoid voltage spikes due to inductive load. Active current wave-shaping technique are also proposed to ensure that the supply current waveform is continuous, sinusoidal and in phase with the supply voltage. This approach utilizes boost rectifier technique for compensation. Selected experimental results are presented to verify the concept.

Single-phase shunt active power filter using single-switch incorporating boost circuit

This paper is concerned on a shunt active power filter for harmonic compensation of a single-phase system feeding non-linear load. An active current wave-shaping technique is proposed to mitigate the distortion current by injecting equal but opposite current to shape the pulsating nature of the supply current to a sinusoidal form and in-time phase with the supply voltage. In the proposed work only one power switch is employed to minimize cost, reduce switching stress and losses. The behaviour and operation of the proposed filter structure was examined with computer simulation and through experimental verification.

Single-phase hybrid active power filter using single switch parallel active filter and simple passive filter

This paper presents an implementation of hybrid active power filter for minimizing the input current distortion in a single-phase system feeding a non-linear load. In this method, the active power filter is injecting equal but opposite current to mitigate the distortion current shape the supply current to a sinusoidal form and in phase with the supply voltage. In this work, the single-switch parallel active power filter is used to reduce switching stress, losses and also the cost. Studies are performed to evaluate the performance of this topology in conjunction with a simple passive filter in a hybrid arrangement using two components; a parallel active power filter and a passive filter for removing both high order and low order harmonics. The passive filter uses simple LC configuration; whilst the parallel active filter uses a single-switch topology typically used in boost rectifier circuit. Theoretical, simulation and experimental result are presented to prove the validity of this arrangement.

Performance improvement of induction motor drive using simplified FLC method

This paper presents the improvement method for simplified Fuzzy Logic Controller (FLC) for Induction Motor Drive. This method is aimed to enhance performance for variable speed drive performance in a rated forward and reverse operation. The implementation of simplified rules based is able to reduce the computational burden and memory space limitation. However, the speed performance shows some degradation with regards to simplification process. Thus, the propose improvement method is made to increase the error gain parameter. The membership function (MF) domain for error is increased from nominal 1 to 2. It increases the torque current and improves the speed response. The speed control is applied to the indirect Field Oriented Control method fed with Space Vector Pulse Width Modulation (SVPWM). The real time implementation is done using dSPACE DS1103 controller. The performance results are compared between simplified rules method, simplified rules improvement method and Anti-Windup Proportional Controller (AWPI). The results show improvement in terms of rise time, overshoot and settling time compared to its counterparts.

Implementation of Space Vector Two-Arm Modulation for Independent Motor Control Drive Fed by a Five-Leg Inverter

This paper presents the implementation of two-arm modulation (TAM) technique for the independent control of a two-induction motor drive fed by a five-leg inverter (FLI). A carrier-based space vector pulse width modulation technique for TAM is proposed to generate switching signals for FLI. Two independent three-phase space vecto modulators are utilized to control two motors. The motor drive system applies two separate indirect field-oriented control methods. The stationary voltage outputs from the vector control are synthesized in the three-phase space vector modulator to generate switching signals for FLI. The performance of the independent control of the motors and the voltage utilization factor are likewise analyzed. Simulation and experimental results verify the effectiveness of the proposed method for the independent control of the two-motor drive system. The proposed technique is successfully validated by dSPACE DS1103 experimental work.

Comparative study of different PWM control scheme for three-phase three -wire shunt active power filter

Instantaneous reactive power theory was the most popular control theory used when dealing with harmonics compensations. In conjunction with the instantaneous theory, switching signal generation techniques plays an important role to ensure the correct compensation signal injected in the system. Therefore, this paper discussed on comparative study of five (5) methods used in instantaneous theory namely; p-q method, modified p-q, d-q method, p-q-r method and vectorial with three (3) types of signal generation namely; carrier current control, hysteresis current control and space vector modulation control. Continuous reductions of the total harmonics distortion (THD) are expected at the supply current when applied different types of switching technique. The comparison was examining using MATLAB/Simulink (MLS) environment.

Analysis on speed characteristics of Five Leg Inverter for different carrier based PWM scheme

This paper focused on the performance analysis of two induction motor drive fed by the Five Leg Inverter (FLI). Two carrier based PWM scheme for FLI are used in these motor control analysis which are known as Double Zero Sequence (DZS) Injection Method and Two Arm Modulation (TAM). Simulink/MATLAB is used as the simulation tool for analysis. Detailed investigation of the speed response characteristics under speed command change, load disturbance, steady state stability and dynamic response is performed based on these two schemes. The results reveal that both methods have good capabilities of independently controlling the two motors. Comparison of these methods show that, DZS method has better speed and torque ripple disturbance performance at half rated speed while TAM have better performance at lower rated speed. Further analysis for the same speed demand shows that TAM has better capability for a higher same speed operation range.

Characteristic of Induction Motor Drives Fed by Three Leg and Five Leg Inverters

This paper aims to compare the performance of three phase induction motor drives using Five Leg Inverter (FLI) and Three Leg Inverter (TLI) configurations. An Indirect Field Oriented Control (IFOC) method using a TLI is well established and incorporated for high performance speed drives in various industries. The FLI dual motor drive system on the other hand shows good workability in the independent control of two induction motor drives simultaneously. In this experiment, the IFOC method is utilized for both drive systems, and Space Vector Pulse Width Modulation (SVPWM) is used to generate pulses for both inverters. For the FLI, the Double Zero Sequence (DZS) Injection technique is used to generate the modulation signal. The complete experiment setup is done by using a DSpace 1103 controller board. The individual motor performances are analyzed using similar schemes, equipment setups and controller parameter values. The results show similar speed performance response capability between the single motor operation using a TLI system and the two motor operation using a FLI system based on the variable speed range either in forward or reverse operation. They also show similar load rejection abilities. However, the single motor with a TLI has a better power quality aspect such as ripple current and total harmonics distortion (THD).

Kalman Filters for Reference Current Generation in Shunt Active Power Filter (APF)

Shunt active power filter (APF) method have been used by many researchers as a solution in reducing the harmonics creating by the non-liner loads. Therefore, this research is targeted to design and implement a three-phase shunt APF employing Kalman filter estimator. Conventionally, low-pass filter (LPF) is used to filter out the unwanted DC component of the non-linear load to produce the sinusoidal waveform called the reference current. However, when applying LPF it contributes with the phase shift and high transient at the supply current. Therefore, to reduce these problems, the digital Kalman filter estimator is used to replace the LPF for generating the reference current. Details on the investigation between conventional and proposed methods under simulation based on Matlab Simulink platform and experimental that are made for two types of load, namely, three-phase rectifier with RC-load and three-phase induction motor, are presented. The performance criteria of the shunt APF are determined by the supply current waveform, total harmonic distortion (THD), harmonic spectrum and power quality measurements, which were also obtained by simulation and experimental. In conclusion, by employing Kalman filter estimator for generating the reference current, it reduces the time delay and high transient current at the power supply and, thus, improved the overall THD from 0.1 to 0.42% compared to the LPF.

Three-Phase Reference Current Generator Employing with Kalman Filter for Shunt Active Power Filter

This paper presents a new technique of reference current generator based on Kalman filter (KF) estimator for three-phase shunt active power filter (APF). The stationary reference frame (d-q algorithm) is used to transform the load currents into DC component. The harmonics of load currents are extracted and the three-phase reference currents are generated using KF estimator. The work is simulated using Matlab/Simulink platform. To validate the simulation results, an experimental test-rig have been perform using real-time control dSPACE DS1104. In addition, hysteresis current control was used to generate the switching signal for the correction of the harmonics in the system. The nonlinear load were constructed with three-phase rectifier which connected in series with inductor and parallel with resistor and capacitor. The results shows that the new technique of shunt APF embedded with KF is proven to eliminate the harmonics created by the non-linear load with some improvement on the total harmonics distortion (THD).