TMS320F28335 Digital Signal Processor Research Articles

Fundamental Active Current Adaptive Linear Neural Networks for Photovoltaic Shunt Active Power Filters

This paper presents improvement of a harmonics extraction algorithm, known as the fundamental active current (FAC) adaptive linear element (ADALINE) neural network with the integration of photovoltaic (PV) to shunt active power filters (SAPFs) as active current source. Active PV injection in SAPFs should reduce dependency on grid supply current to supply the system. In addition, with a better and faster harmonics extraction algorithm, the SAPF should perform well, especially under dynamic PV and load conditions. The role of the actual injection current from SAPF after connecting PVs will be evaluated, and the better effect of using FAC ADALINE will be confirmed. The proposed SAPF was simulated and evaluated in MATLAB/Simulink first. Then, an experimental laboratory prototype was also developed to be tested with a PV simulator (CHROMA 62100H-600S), and the algorithm was implemented using a TMS320F28335 Digital Signal Processor (DSP). From simulation and experimental results, significant improvements in terms of total harmonic distortion (THD), time response and reduction of source power from grid have successfully been verified and achieved.

Galvanically isolated high gain Y‐source DC–DC converters for dispersed power generation

This study deals with a novel high voltage gain isolated dc–dc converter that utilise a versatile Y-source for its boosting stage. Having Y-source impedance network, isolation transformer and voltage doubling rectifier, the proposed converter can achieve high voltage gain with reduced stress on its components. Since continuous input current (CIC) ability is an advantageous characteristic of dc–dc converters tied to renewable energy sources, a CIC version of the proposed converter is well demonstrated and discussed in the study. In addition, detailed operation principles of the proposed converters are mathematically expressed. Simulation results from Simulink\Pspice interface have examined the performance of proposed converters in both boost and normal operation modes. Finally, a laboratory prototype was built to evaluate the theoretical assumptions. Besides, in the experiment a TMS320F2812 digital signal processor board was used for generating the shifted shoot-through control method. Experimental results in both operation modes show a reliable performance for the proposed CIC converter and its counterpart.

Single pole switch leg based multi‐port converter with an energy storage

This study presents a new multi-functional control system for a multi-port energy converter that interfaces one bi-directional battery port, one dc input port, and three output ports. Only one single-leg active switching element (a module type can be used) is employed in the system, and hence the single leg requires digital switching signals for a multi-functional operation to regulate output voltages and to simultaneously manage the battery port. The proposed system has buck-boost conversion capabilities to accommodate wide range, various input sources and output loads. In addition, the single leg requires no dead time due to an integrated impedance network, which will improve the system reliability and performance. Furthermore, the proposed structure can charge a battery even when the input and capacitor voltages are much lower than the battery voltage and hence it significantly improves charging behaviours. The proposed multi-functional control strategy and the converter structure are explained in detail. Then the feasibility and performance of the converter are verified both by computer simulations and experiments based on the Texas Instruments TMS320F28335 digital signal processor.

Feedback Linearization Direct Torque Control With Reduced Torque and Flux Ripples for IPMSM Drives

This paper designs a feedback linearization direct torque control (FL-DTC) based on the space vector modulation (SVM) which can noticeably reduce the electromagnetic torque and stator flux ripples that affect the system efficiency on interior permanent magnet synchronous motor (IPMSM) drives. First, a decoupled linear IPMSM model with two state variables (i.e., the stator flux and electromagnetic torque) is derived to implement the proposed FL-DTC strategy that preserves some advantages such as fast torque control, high torque at low speed, and fast speed response. Also, the proposed technique greatly alleviates the torque and stator flux ripples which are the major concerns of the classical hysteresis-based DTC scheme and have an effect on the stator current distortion. The system stability with the designed FL-DTC method is mathematically analyzed using the Lyapunov stability theory. Finally, the effectiveness of the proposed control law is validated through simulation results with MATLAB/Simulink and experimental results obtained from a prototype 1-HP IPMSM drive with TI TMS320F28335 digital signal processor (DSP). The verification results demonstrate that the proposed FL-DTC scheme achieves faster torque response, smaller torque ripple, and lower stator flux ripple than the conventional SVM-based PI-DTC approach under parameter uncertainties and external disturbances.

Improving the Dynamic Response during Field Weakening Control of IPMSM Drive System using Adaptive Hysteresis Current Control Technique

Abstract This paper presents the control of IPMSM drive in flux weakening region, for high speed applications. An adaptive hysteresis band current controller has been designed and implemented in this work to overcome the drawbacks which are present in case of conventional hysteresis band current controllers such as: high torque ripple, more current error, large variation in switching frequency etc. The proposed current controller is a hysteresis controller in which the hysteresis band is programmed as a function of variation of motor speed and load current. Any variation in those parameters causes an appropriate change in the band which in turns reduces the torque ripple as well as current error of the machine. The proposed scheme is modeled and tested in the MATLAB-Simulink environment for the effectiveness of the study. Further, the result is validated experimentally by using TMS320F2812 digital signal processor.

Implementation of ANN-based Selective Harmonic Elimination PWM using Hybrid Genetic Algorithm-based optimization

A PWM technique with Selective Harmonic Elimination (SHE) is used to control fundamental harmonic and eliminate harmonics of chosen lower-order in voltage source inverters (VSI). Therefore, this PWM technique requires the determination of the optimum switching angles by solving the nonlinear equation set. The determined angles are recorded on a look-up table to generate PWM signals in real-time systems. The paper proposes two Artificial Neural Networks (ANN) based solution for determining angles and generating PWM signals. ANN generates optimum switching angels for all modulation index between 0 and 1.20 because of it has learning capability differently from the look-up table. Primarily, the optimum 11-switching angles for three-phase two-level inverter are determined by using offline Hybrid Genetic Algorithm (HGA). The first ANN was trained by the data obtained from HGA to calculate the switching angles without using a look-up table. Second ANN was trained by using these switching angles to generate PWM signals. The ANN-based SHEPWM was designed to obtain inverter output voltage which has a bipolar waveform with quarter-wave symmetry. The algorithm of ANN-based SHEPWM is performed by using TMS320F28335 Digital Signal Processor (DSP). The experimental results related to dc-link voltage, inverter output voltage and load current are measured for different Ma by using scope and power quality analyzer. The waveform of inverter output voltage are also analyzed with FFT for an induction motor load. The low-order harmonics are successfully eliminated by proposed ANN based SHEPWM.

Advanced induction motor drive control with single current sensor

This paper proposes induction motor drive control method which uses minimal number of sensors, providing only DC-link current as a feedback signal. Improved DC-link current sampling scheme and modified asymmetrical switching pattern cancels characteristic waveform errors which exist in all three reconstructed motor line-currents. Motor linecurrent harmonic content is reduced to an acceptable level, eliminating torque and speed oscillations which were inherent for conventional single sensor drives. Consequently, use of single current sensor and line-current reconstruction technique is no longer acceptable only for low and medium performance drives, but also for drives where priority is obtaining a highly accurate, stable and fast response. Proposed control algorithm is validated using induction motor drive hardware prototype based on TMS320F2812 digital signal processor.

Experimental evaluation of a partially shaded photovoltaic system with a fuzzy logic‐based peak power tracking control strategy

Partial shading on photovoltaic (PV) array makes the task of operating the PV system at its peak power more complex due to multiple peak points on power–voltage (P–V) characteristic. Amongst multiple peaks, it is challenging to find global peak as there is a possibility of the system getting stuck at a local peak otherwise considerable loss of power may occur. In this study, experimental evaluation of a novel algorithm which tracks global peak is presented. The algorithm is capable of tracking the peak power under all partial shadowing and uniformly varying insolation conditions. The algorithm scans the entire P–V curve in larger steps by varying the duty cycle of DC–DC converter without missing any peak to determine approximate location of peak power point and then uses fuzzy logic to track the real global peak. The algorithm is verified through simulation and the results are validated through hardware implementation using TMS320F28335 digital signal processor. The experimental results match with the simulation results that justify the performance and robustness of the proposed algorithm for tracking global peak power when the PV array is partially shaded. The comparative evaluation of the proposed algorithm with conventional perturb and observe-based method is also carried out experimentally.

Improving the SRF method to compensate low-order harmonics under nonsinusoidal network voltages

Increasing the application of power in electronic devices has increased the harmonics in power systems. Numerous methods like the synchronous reference frame (SRF) and the p-q-based method have been suggested to overcome the effects of these harmonics. The conventional SRF method provides acceptable results in harmonic compensation of high-order harmonics (higher than the fourth order), but the transient response time will be drastically increased in the presence of low-order harmonics due to the existence of a conventional low-pass filter. Furthermore, if the load terminal voltages are distorted, then the conventional SRF method will become unable to implement load current compensation. This research has used wavelet transform to overcome these difficulties. The proposed method is not only faster than conventional SRF, but it can also compensate the load currents if the load terminal voltages are also distorted. The simulation and experimental results are performed using MATLAB/Simulink and digital signal processor TMS320F28335 to verify the proposed method.

Wavelet-fuzzy speed indirect field oriented controller for three-phase AC motor drive – Investigation and implementation

Three-phase voltage source inverter driven induction motor is used in many medium- and high-power applications. Precision in speed of the motor play vital role, i.e. popular methods of direct/indirect field-oriented control (FOC) are applied. FOC is employed with proportional–integral (P-I) or proportional–integral–derivative (P-I-D) controllers and they are not adaptive, since gains are fixed at all operating conditions. Therefore, it needs a robust speed controlling in precision for induction motor drive application. This research paper articulates a novel speed control for FOC induction motor drive based on wavelet-fuzzy logic interface system. In specific, the P-I-D controller of IFOC which is actually replaced by the wavelet-fuzzy controller. The speed feedback (error) signal is composed of multiple low and high frequency components. Further, these components are decomposed by the discrete wavelet transform and the fuzzy logic controller to generate the scaled gains for the indirect FOC induction motor. Complete model of the proposed ac motor drive is developed with numerical simulation Matlab/Simulink software and tested under different working conditions. For experimental verification, a hardware prototype was implemented and the control algorithm is framed using TMS320F2812 digital signal processor (dsp). Both simulation and hardware results presented in this paper are shown in close agreement and conformity about the suitability for industrial applications.

Autotuning Controller for Motion Control System Based on Intelligent Neural Network and Relay Feedback Approach

In this paper, we introduce a proportional-integral-derivative (PID) autotuning controller using an intelligent neural network control based on the relay feedback approach. The proposed controller takes advantage of offline learning and self-learning capability of the online control strategy, in which the initial knowledge of the control system is recognized by the relay feedback approach, and the online learning capability of the neural network controller helps the control system respond quickly to the dynamics changes. Furthermore, the proposed control algorithms are implemented in the high performance digital signal processor TMS320F28335. The robustness and motion tracking performance are validated through simulation and experimental results.

금속 부품의 결함 판단을 위한 고유 주파수 분석 시스템 개발

In this study, we developed a system to detect the various defects in the metallic objects using the phenomenon that the defects cause the changes of the natural resonant frequencies. Our system consists of a FFT Amp, an Auto Impact Hammer, a Hammer controller and a PC. Auto Impact Hammer creates vibrations in the metallic objects when tapped on the surface. These vibrational signals are converted to the voltage signals by an acceleration sensor attached to the metallic part surface. These analog voltage signals were fed into an ADC (analog-digital converter) and an FFT (fast fourier transform) conversion in the FFT Amp to obtain the digital data in the frequency domain. Labview graphical program was used to process the digital data from th FFT amp to display the spectrum. We compared those spectra with the standard spectrum to find the shifts in the resonant frequencies of the metal parts, and thus detecting the defects. We used PCB's acceleration sensor and TI's TMS320F28335 DSP (digital signal processor) to obtain the resolution of 2.93 Hz and to analyze the frequencies up to 44 kHz.

A Class of Quasi-Switched Boost Inverters

A switched boost inverter (SBI) can replace a $Z$ -source inverter (ZSI) in low-power applications because it has one less $LC$ pair than the ZSI. This paper presents a class of quasi-SBIs (qSBIs) that offers several advantages when compared with a conventional SBI, including reducing the voltage stress on the capacitor, increasing the boost voltage factor, and improving input current profiles. Operating principles, steady-state analysis, and comparisons with conventional inverters are presented. A prototype based on a TMS320F28335 digital signal processor is built to verify the operating principle of the proposed qSBIs.

Development board based on the TMS320F28335 DSP for applications of power electronics

This paper presents the design of a special purpose development board for power applications based on the digital signal processor (DSP) TMS320F28335. We also propose some considerations for the design of any four-layer printed circuit line with international recommendations to counteract the EMI (electromagnetic interference) and increase the EMC (electromagnetic compatibility). Additionally, the main features of each module on the board and their respective conditioning circuits designed are presented in order for the development board to be useful for any application of power electronics as motor control, switching power supplies, LED lighting, communications through the electric network, etc. Finally, a test protocol to verify the performance of the card and the comparison between the final cost per unit and similar cards on the market were performed.

Control strategy and hardware implementation for DC–DC boost power circuit based on proportional–integral compensator for high voltage application

For high-voltage (HV) applications, the designers mostly prefer the classical DC–DC boost converter. However, it lacks due to the limitation of the output voltage by the gain transfer ratio, decreased efficiency and its requirement of two sensors for feedback signals, which creates complex control scheme with increased overall cost. Furthermore, the output voltage and efficiency are reduced due to the self-parasitic behavior of power circuit components. To overcome these drawbacks, this manuscript provides, the theoretical development and hardware implementation of DC–DC step-up (boost) power converter circuit for obtaining extra output-voltage high-performance. The proposed circuit substantially improves the high output-voltage by voltage-lift technology with a closed loop proportional–integral controller. This complete numerical model of the converter circuit including closed loop P-I controller is developed in simulation (Matlab/Simulink) software and the hardware prototype model is implemented with digital signal processor (DSP) TMS320F2812. A detailed performance analysis was carried out under both line and load regulation conditions. Numerical simulation and its verification results provided in this paper, prove the good agreement of the circuit with theoretical background.

Improvement of Dynamic Behavior of Shunt Active Power Filter Using Fuzzy Instantaneous Power Theory

Dynamic behavior of the harmonic detection part of an active power filter (APF) has an essential role in filter compensation performances during transient conditions. Instantaneous power (p?q) theory is extensively used to design harmonic detectors for active filters. Large overshoot of p?q theory method deteriorates filter response at a large and rapid load change. In this study the harmonic estimation of an APF during transient conditions for balanced three-phase nonlinear loads is conducted. A novel fuzzy instantaneous power (FIP) theory is proposed to improve conventional p?q theory dynamic performances during transient conditions to adapt automatically to any random and rapid nonlinear load change. Adding fuzzy rules in p?q theory improves the decomposition of the alternating current components of active and reactive power signals and develops correct reference during rapid and random current variation. Modifying p?q theory internal high-pass filter performance using fuzzy rules without any drawback is a prospect. In the simulated system using MATLAB/SIMULINK, the shunt active filter is connected to a rapidly time-varying nonlinear load. The harmonic detection parts of the shunt active filter are developed for FIP theory-based and p?q theory-based algorithms. The harmonic detector hardware is also developed using the TMS320F28335 digital signal processor and connected to a laboratory nonlinear load. The software is developed for FIP theory-based and p?q theory-based algorithms. The simulation and experimental tests results verify the ability of the new technique in harmonic detection of rapid changing nonlinear loads.

Single‐phase ac–dc–ac multilevel five‐leg converter

In this study, a multilevel five-leg single-phase ac–dc–ac converter and its generalisation are presented. The converter is suitable to be used as an uninterrupted power supply or a unified power quality conditioner without an isolation transformer. The operating principles, the pulse-width modulation strategy and the control system for the proposed converter are presented. The proposed single-phase multilevel ac–dc–ac converter is composed mostly of low-power switches capable of generating input and output voltages with low harmonic content. The proposed configuration is compared with the conventional solution in terms of harmonic distortion, semiconductor losses and ratings of switches. Experimental results demonstrate the feasibility of the proposed configuration. The experimental verification of the proposed topology and control strategy was obtained by using IGBTs with dedicated drives and a digital signal processor TMS320F28335 with plug-in boards and sensors.

DSP-Based Modified SPWM Switching Technique with Two-Degrees-of-Freedom Voltage Control for Three-Phase AC–DC Buck Converter

This paper presents a modified sinusoidal pulse-width modulation (SPWM) switching technique in three-phase ac–dc buck converter with new modulation strategy. The modulation strategy used two reference signals (0°–60° and 120°–180° sine wave) and one type of carrier signal, instead of two types of carrier signal to generate pulse-width modulation signals. A conventional 6-switch three-phase ac–dc buck converter is extended by comprising four diodes in each switch to achieve bidirectional power flow capability. A digital feedback voltage control using two-degrees-of-freedom-control approach is implemented to achieve the output voltage to equal the reference voltage with high dynamic performance and to obtain sinusoidal ac current with unity power factor. The modified SPWM switching strategy of ac–dc power flow and vice versa is discussed and verified via mathematical model. The validity of the proposed three-phase ac-dc buck converter with bidirectional capability its PWM and the feedback control strategy is verified through simulation and is implemented in a prototype using TMS320F28335 Digital Signal Processor.

Sensorless Sliding-Mode Rotor Speed Observer of Induction Machines Based on Magnetizing Current Estimation

This paper presents a rotor speed observer for induction-machine drives based on a sliding-mode approach and magnetizing current estimation. The back electromotive force (EMF) is calculated from the stator current and the stator voltage signals. The magnetizing currents are obtained from the back EMF. A theorem which gives the rotor speed estimate in the continuous-time domain is formulated using the magnetizing current estimation. The stability analysis is achieved based on the Lyapunov approach. Moreover, the discrete-time approach of the method is discussed, and a theorem for the discrete-time implementation is proposed. The limits that ensure the system stability for the switching gains and for the observer gain are discussed. This paper shows that the limits for the gains of the discrete-time algorithm are different from the limits for the gains of the continuous-time algorithm. Simulation results are presented to validate the theoretical analysis. In addition, experimental results based on a fixed-point digital signal processor (DSP) platform (DSP TMS320F2812) demonstrate the performance of the proposed scheme.

A maximum power point tracking algorithm for photovoltaic systems using bang-bang controller

In this paper, an algorithm for maximum power point tracking (MPPT) for photovoltaic based generation systems has been proposed. The technique is primarily based on “bang-bang” (hysteresis) control strategy. It is implemented using digital signal processor (DSP) TMS320F2812, which controls the DC-DC boost converter to enhance accuracy and speed. Code Composer Studio v3.1 is used to program DSP TMS320F2812. As compared to the conventional techniques for MPPT, the proposed configuration results in a simple configuration and a good overall efficiency. A complete description of various aspects of the system is presented, such as converter design, programming of the controller, and tuning of system components. Results obtained from simulation studies and experimental investigations show conformity to the proposed concepts.