Shunt Active Power Filter Employing Kalman Filter Estimator For Harmonics Reduction

The wide use of non-linear loads, such as front-end rectifiers connected to the power distribution systems for DC supply or inverter-based applications, causes significant power quality degradation in power distribution networks in terms of current or voltage harmonics, power factor, and resonance problems. Many techniques have been proposed by the researchers to overcome these problems. One of the method is by using shunt active power filter (APF). This technique is an effective solution for reducing the current harmonics for low to medium power applications. Therefore, this research is targeted to design and implement a three-phase shunt APF employing Kalman filter estimator. The first step is designing the shunt APF circuit by deploying voltage source inverter (VSI). However, when using VSI the DC voltage needs to be maintained because its influence the real power conversion hence degrades the performance of the APF. Two methods are used to overcome this problem namely are conventional PI and PI-improved method. Both methods have been simulated under voltage variation and open circuit test. The results show that PI-improved voltage regulator produce better performance in reduction of the THD as the results reduce the surge current. On the other hands, three common controllers of the shunt APF for generation of reference current are compared and analysed to determine the best performance of THD reduction. Based on the results, the d-q reference current generator produces the lowest THD among others. 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 reference current. However, when applying LPF it contribute 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 investigation between conventional and proposed method under simulation based on Matlab simulink platform and experimental are made for three types of load namely three-phase rectifier with R-load, 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, THD, harmonics spectrum and power quality measurements were also obtained by simulation and experimental. In conclusion, by employing Kalman filter estimator for generating the reference current it reduce the time delay and high transient current at the power supply thus, improved the overall THD from 0.15% to 0.42% compared to the LPF

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

High frequency signal injection method for sensorless permanent magnet synchronous motor drives

The objective of this project is to design a high frequency signal injection method for sensorless control of permanent magnet synchronous motor (PMSM) drives. Generally, the PMSM drives control requires the appearance of speed and positon sensor to measure the motor speed hence to feedback the information for variable speed drives operation. The usage of the sensor will increase the size, cost, extra hardwire and feedback devices. Therefore, there is motivation to eliminate this type of sensor by injecting high frequency signal and utilizing the electrical parameter from the motor so that the speed and positon of rotor can be estimated. The proposed position and speed sensorless control method using high frequency signal injection together with all the power electronic circuit are modelled using Simulink. PMSM sensorless driveis simulated and the results are analyzed in terms of speed, torque and stator current response without load disturbance but under the specification of varying speed, forward to reverse operation, reverse to forward operation and step change in reference speed. The results show that the signal injection method performs well during start-up and low speed operation

Improved direct torque control load torque estimator with the influence of steering angle for dual induction motors electric vehicle traction drive system

Front-wheel direct-driven dual motors of an electric vehicle (EV) with a single controller configuration offer great potential and flexibility for improving system performance, efficiency and safety. The objective of the paper is to design a new load torque estimator of Direct Torque Control (DTC) by merging the electrical model with the mechanical model of an EV traction system to improve the dual motors single controller configuration. The electrical model utilise Space Vector PWM (SVPWM) DTC control of dual induction motors fed Five-leg Inverter (FLI) while the mechanical model takes the 14DOF vehicle dynamic model as its main structure. The new technique used is by integrating lateral force with longitudinal force produced at the touch point of a tyre with road surface as the input to the new load torque estimator of DTC. The new load torque estimator technique results were, then, compared with the standard load torque estimator that used the voltage and current feedback only. The findings showed that while torque estimator of conventional DTC had no effect of steering angle on the speed, torque and current performance of the motors, the new load torque estimator showed a significant impact. The speed, torque and current responds of the motors now have precisely been estimated; following the trajectory of the steering angle. Hence, for future research the new load torque estimator with the accurate and precise speed and torque response can further be utilized in stability, slip and skid and traction control or even for electronic braking system

Comparison Analysis of Indirect FOC Induction Motor Drive using PI, Anti-Windup and Pre Filter Schemes

This paper presents the speed performance analysis of indirect Field Oriented Control (FOC) induction motor drive by applying Proportional Integral (PI) controller, PI with Anti-Windup (PIAW) and Pre- Filter (PF). The objective of this experiment is to have quantitative comparison between the controller strategies towards the performance of the motor in term of speed tracking and load rejection capability in low, medium and rated speed operation. In the first part, PI controller is applied to the FOC induction motor drive which the gain is obtained based on determined Induction Motor (IM) motor parameters.  Secondly an AWPI strategy is added to the outer loop and finally, PF is added to the system. The Space Vector Pulse Width Modulation (SVPWM) technique is used to control the voltage source inverter and complete vector control scheme of the IM drive is tested by using a DSpace 1103 controller board. The analysis of the results shows that, the PI and AWPI controller schemes produce similar performance at low speed operation. However, for the medium and rated speed operation the AWPI scheme shown significant improvement in reducing the overshoot problem and improving the setting time. The PF scheme on the other hand, produces a slower speed and torque response for all tested speed operation. All schemes show similar performance for load disturbance rejection capability

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)

Implementation of Anti-Windup PI Speed Controller for Induction Motor Drive Using dSPACE and Matlab/Simulink Environment

This paper presents the design, analysis and implementation of speed control drive indirect Field Oriented Control (FOC) induction motor using a dSPACE DS1103 digital-signal-processor-based real-time data acquisition control system and MATLAB/Simulink environment. The details design of speed control indirect Field Oriented Control (FOC) induction motor drive with Anti-Windup PI controllers' (AWPI) is discussed. In addition, the controller designed is focused on the mathematical determination of proportional integral (PI) controller which is usually obtained by trial and error approached. Three PI controllers are used in speed and current loops to control the Space Vector Pulse Width Modulation Technique (SVPWM) in FOC scheme. Simulation and experimental test results at rated voltage, speed and load disturbance are verified the effectiveness of the design approached

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