Digital Signal Controller Research Articles

Serial resonant converter (SRC) polynomial model implemented in a digital signal controller (DSC)

AbstractThis work describes the process of modelling resonant converters by means of polynomial equations, in such a way that they can be easily implemented in digital controllers as digital signal controller. As an example, the serial resonant converter is modelled and its implementation in the TMS320F28335 Texas Controller.

An innovative 11-level multilevel inverter topology with rotating trapezoidal SPWM for industrial and renewable applications

This paper provides a new, less complex multilevel inverter topology that can be used for industrial loads and renewable energy sources. The arrangement consists of eight switches to produce an 11-level output voltage with two uneven input sources. Moreover, it can be connected in a cascade to increase the output voltage and number of levels even further. Due to its control mechanism, which is based on the Rotating Trapezoidal Sinusoidal Pulse Width Modulation control method for creating a high-quality output voltage, the inverter’s key characteristic is its very low harmonic distortion of 3.45% at the output voltage when compared to the advanced triangular carrier-based PWM techniques of phase disposition sinusoidal pulse width modulation (PD-SPWM) it produces harmonic distortion of 11.38% at the output voltage, phase opposition disposition sinusoidal pulse width modulation (POD-SPWM) it produces harmonic distortion of 6.43% at the output voltage, alternative phase opposition disposition sinusoidal pulse width modulation (APOD-SPWM) it produces harmonic distortion of 6.69% at the output voltage, IN-Shift sinusoidal pulse width modulation (IN-shift SPWM) it produces harmonic distortion of 3.93% at the output voltage. This inverter is commonly used in wind turbines and solar cells. The schemes are implemented in MATLAB/SIMULINK and are validated with single-phase 11-level inverter implemented by using digital signal controller (DSC).

Any-nucleus distributed active programmable transmit coil.

There are 118 known elements. Nearly all of them have NMR active isotopes and at least 39 different nuclei have biological relevance. Despite this, most of today's MRI is based on only one nucleus-1H. To facilitate imaging all potential nuclei, we present a single transmit coil able to excite arbitrary nuclei in human-scale MRI. We present a completely new type of RF coil, the Any-nucleus Distributed Active Programmable Transmit Coil (ADAPT Coil), with fast switches integrated into the structure of the coil to allow it to operate at any relevant frequency. This coil eliminates the need for the expensive traditional RF amplifier by directly converting direct current (DC) power into RF magnetic fields with frequencies chosen by digital control signals sent to the switches. Semiconductor switch imperfections are overcome by segmenting the coil. Circuit simulations demonstrated the effectiveness of the ADAPT Coil approach, and a 9 cm diameter surface ADAPT Coil was implemented. Using the ADAPT Coil, 1H, 23Na, 2H, and 13C phantom images were acquired, and 1H and 23Na ex vivo images were acquired. To excite different nuclei, only digital control signals were changed, which can be programmed in real time. The ADAPT Coil presents a low-cost, scalable, and efficient method for exciting arbitrary nuclei in human-scale MRI. This coil concept provides further opportunities for scaling, programmability, lowering coil costs, lowering dead-time, streamlining multinuclear MRI workflows, and enabling the study of dozens of biologically relevant nuclei.

Low-noise preamplifier for scanning tunneling microscope

The current preamplifier is one of the important components of the scanning tunneling microscope (STM), and its performance is crucial to the basic operations of the STM system, as well as for the development of demanding novel functionalities such as autonomous atomic fabrication. In this study, the factors that affect the performance of a current preamplifier, including its noise spectrum density and the bandwidth, are analyzed in depth, and a preamplifier is designed and fabricated specifically for the STM system. By using a carefully selected low-noise op amp chip, the optimized current preamplifier has a noise floor as low as 4 <inline-formula><tex-math id="M2">\begin{document}$ {\mathrm{f}}{\mathrm{A}}/\sqrt{{\mathrm{H}}{\mathrm{z}}} $\end{document}</tex-math><alternatives><graphic specific-use="online" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20240560_M2.jpg"/><graphic specific-use="print" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20240560_M2.png"/></alternatives></inline-formula> and a bandwidth of 2.3 kHz, at its most sensitive transimpedance gain of 1 GΩ. It has three transimpedance gains, 10 MΩ, 100 MΩ, and 1 GΩ, that can be switched through digital control signals. A two-switch configuration is adopted to minimize the noise floor while maintaining the optimal bandwidth. The current detectable by this three-level preamplifier ranges from pA to μA, satisfying the requirements of most STM operations. Using this preamplifier, the fundamental functions of the STM system are successfully demonstrated, including surface topographic characterization, scanning tunneling spectroscopy, and single atom/molecule manipulation. The measurement of shot noise in tunneling current is also explored, and a linear relationship between shot noise and tunneling current is obtained by carefully analyzing noise. It is illustrated that the Fano factor of the shot noise in a normal metallic tunneling junction is approximately equal to 1, revealing the expected Poisson process for electron tunneling in such a scenario. The results are valuable for the high-resolution characterization of correlation systems in the future.

Review on FPGA Implementation of CORDIC Algorithm

The Coordinate Rotation Digital Computer (CORDIC) algorithm has emerged as a pivotal method for executing trigonometric and various mathematical operations within digital systems. Field-Programmable Gate Arrays (FPGAs) have witnessed a remarkable surge in adoption for implementing the CORDIC algorithm owing to their inherent flexibility and exceptional performance capabilities. This paper endeavours to provide a comprehensive overview of FPGA implementations of the CORDIC algorithm, elucidating both the advantages and challenges associated with this methodology. It thoroughly examines various FPGA architectures customized for CORDIC implementation, meticulously analyzing their respective trade-offs regarding resource utilization, performance metrics, and accuracy levels. Moreover, the paper explores numerous applications where the FPGA-based CORDIC algorithm shines, illustrating its adaptability across diverse domains like digital signal processing and control systems. These applications underscore the algorithm's efficacy in addressing real-world challenges and its potential to significantly augment system performance and efficiency.By furnishing profound insights into FPGA-based CORDIC implementations, this paper serves as an invaluable resource for engineers and researchers keen on harnessing the capabilities of FPGAs for high-performance mathematical computations in digital systems.

A Novel ANN-Based GMPPT Method for PV Systems Under Complex Partial Shading Conditions

In this paper, a new two-stage global maximum power point tracking (GMPPT) algorithm based on artificial neural network (ANN) is proposed. The novel ANN architecture is presented first, which requires fewer sampling points than other ANN-based GMPPT approaches, thereby reducing both the tracking time and power loss involved in the tracking. In addition, it does not require costly illuminance or temperature sensors and can be realized using a low-cost digital signal controller. According to the simulation results, the proposed method has the best performance among all methods in terms of tracking speed, tracking accuracy, and tracking loss for all the three tested shading patterns (SPs). The simulated results of 252 SPs show that the performance indexes (PIs) of the proposed method are the best among all the compared methods, which are: the average tracking time 0.18 seconds, average power loss 0.01 W. In addition, the proposed method can correctly predict the GMPP positions of all 252 SPs. Furthermore, the PIs of the proposed method are also the best among all the compared methods according to the experimental results, which are: the tracking speed 0.21 seconds, tracking accuracy 99.66%, and tracking loss 12.58 W, all the above are average values.

A single current sensor based adaptive step size MPPT control of a small scale variable speed wind energy conversion system

Due to the limited size and lower environmental impact, a small-scale wind energy conversion system (WECS) is a promising alternative for remote locations and residential areas where installing large wind turbines is not feasible. This system employs a permanent magnet synchronous generator (PMSG) as a variable speed wind generator due to its advantages such as high torque density, gearless, and require no external excitation, etc. This article proposes a single load current sensor-based adaptive step size (LCAS) maximum power point extraction (MPPT) method which utilizes the load current information to track the maximum power. This method does not require rotor speed information and knowledge of the turbine parameters. Also, this article uses a simple and cost-effective switch mode rectifier topology (AC–DC and DC–DC boost converters) for the PMSG-based variable speed WECS. The proposed method is validated in a 1.5 kW test rig using an OPAL-RT digital signal controller and also compared with various fixed step size (FSS) MPPT algorithms at various operating conditions. Extensive experimental work has been carried out for the LCAS MPPT method that confirms the tracking efficiency is better and tracking speed is faster along with the improved steady state as well as transient performance.

Endovascular Brain-Computer Interfaces in Poststroke Paralysis.

Stroke is a leading cause of paralysis, most frequently affecting the upper limbs and vocal folds. Despite recent advances in care, stroke recovery invariably reaches a plateau, after which there are permanent neurological impairments. Implantable brain-computer interface devices offer the potential to bypass permanent neurological lesions. They function by (1) recording neural activity, (2) decoding the neural signal occurring in response to volitional motor intentions, and (3) generating digital control signals that may be used to control external devices. While brain-computer interface technology has the potential to revolutionize neurological care, clinical translation has been limited. Endovascular arrays present a novel form of minimally invasive brain-computer interface devices that have been deployed in human subjects during early feasibility studies. This article provides an overview of endovascular brain-computer interface devices and critically evaluates the patient with stroke as an implant candidate. Future opportunities are mapped, along with the challenges arising when decoding neural activity following infarction. Limitations arise when considering intracerebral hemorrhage and motor cortex lesions; however, future directions are outlined that aim to address these challenges.

Hardware-in-the-loop testing of grid-tied PMSG-based wind power generation system with optimum PI parameters

The regulators based on PI control law continue to be the key elements in many of the industrial systems for their control. Likewise, the wind power generation systems (WPGSs) also make extensive use of PI regulators in their control schemes. The enhanced performance of these WPGS depends on proper selection of the PI regulator parameters. This paper deals with the control of a grid-tied permanent magnet synchronous generator (PMSG)-based WPGS wherein, a new attempt has been depicted to apply the most optimum design of the involved PI regulator parameters for the proposed WPGS based on standard performance indices making use of four popular optimization algorithms namely genetic algorithm (GA), cultural algorithm (CA), particle swarm optimization (PSO) and artificial bee colony (ABC). An informative discussion has also been presented which would be useful for practicing engineers/researchers to select flexibly and reasonably the PI regulators parameters meant for the control of the proposed WPGS. A detailed simulation model developed in MATLAB/Simulink has been used to analyze the performance of the proposed PMSG-based WPGS employed with the most optimum values of PI regulator parameters. The performances of WPGS have been compared while the most optimum PI regulator parameters have been included in the control system, and also when incorporating the PI regulator parameters in WPGS control designed via classical d-partition technique. The results obtained under gradually changing wind speed profile show the improvement in the performance of WPGS in terms of peak overshoot, time response and waveform oscillations. The experimental validation of the control performances have been carried out by way of real-time hardware-in-the-loop (HIL) testing making use of Typhoon HIL402 emulator and TMS320F28335 digital signal controller. The obtained real time HIL results are in close agreement to the results obtained in simulations using MATLAB/Simulink. A deviation of less than 4% was observed in the percentage overshoot/undershoot of the PMSG speed and DC link voltage determined through simulation and experimental means under various wind speed conditions.

Assessment of Multi-Phase Conversion and Modified PWM Strategy for Power Converters of Medium-Voltage Induction Motors Drive

Multi pulse and multilevel converters show great potential for use in medium voltage induction motor drive systems due to cascaded design and high-quality output. However, variable-speed medium voltage drives have demanding requirements in enhancement number of pulses with less number of DC sources and converter topologies with reduced component counts. This paper utilizes the phase displacement technique as well as the three-phase to five-phase conversion technique so that the drive system extracts 30-pulse current from the grid supply, which helps to enhance the power quality at the grid end. In this paper, a 30-pulse AC-DC converter based on a 10-pulse converter is designed and implemented to feed a power 4-level cascaded inverter through three DC sources. Apart from this, a modified carrier-based LSPWM technique is used to enhance the performance of the MLI at a low switching frequency. An indirect field-oriented control (IFOC) method is utilized to address the issues of the drive system during dynamic operations. Performance analysis through theoretical and simulation by using the full-scale model is evaluated in terms of voltage and current quality, speed and torque response, losses, and efficiency. Experimental verification is also carried out on a 7.5kW, 415V laboratory prototype using a digital signal controller for implementation of the control scheme.

Portable low-cost and highly accurate programmable triggering controller for confocal spinning disk image scanning microscope

This work presents a very low-cost and highly accurate alternative way of implementing triggering control for a confocal spinning-disk image scanning microscope (CSD-ISM). Instead of using the previously reported hig-cost field programmable gate array (FPGA), that connects to a computer by an internal PCIe bus, we implemented the controller using a simple, low-cost real-time digital signal controller (DSC) development kit that connects to a computer via an external USB channel. The overall time resolution of the controller is better than 10 nanoseconds. The DSC programming is implemented using the free software included in the development kit and no additional commercial software is required. The operation of the CSD-ISM is performed by a 32-bit 150 MHz processor using the software environment Micro-Manager, a popular open-source platform for microscopy. Since software is used to calculate all the necessary times, the output signal is almost limitless.

Adaptive Maximum Power Point Tracking Control Algorithm for Wind Energy Conversion Systems

For small-scale wind energy conversion systems (WECSs), an adaptive maximum power point tracking (MPPT) algorithm is presented in this paper to increase wind energy harvesting. For its adaptability across a wide range of WECSs and quick tracking of maximum power point, the proposed algorithm combines the computational behavior of hill climb search, tip speed ratio, and power signal feedback control algorithms. Using buck–boost-featured single-ended primary inductor converters, the proposed MPPT algorithm is implemented in this paper to extract maximum power from the entire wind velocity profile. A laboratory-scaled dc motor drive-based WECS emulator is used to test the proposed algorithm. The in-lab experimental setup's control schemes are carried out with the help of a 32-bit floating point digital signal controller called TMS320F28335. The experimental results demonstrate that the proposed algorithm's tracking capability is effective and efficient in both sudden and gradual wind conditions.

Comprehensive Controller for Super Sonic Molecular Beam Gas Chromatograph Mass Spectrometer

This paper presents a new, comprehensive digital circuit used for the control of a novel gas chromatograph mass spectrometer (GC-MS) interface that is based on supersonic molecular beam (SMB). The circuit includes a Texas Instruments 150 MHz digital signal controller (DSC), high voltage amplifiers for 8 independent channels and 4 independent channels of high resolution pulse width modulation (PWM). The circuit, along with a sophisticated embedded program and a custom made personal computer (PC) application, control all aspects of the interface: smart filament emission-current stabilization, static and scanning mass-dependent ion-source voltages, transfer-line heater proportional integral differential (PID) controls with thermocouple feedbacks, on/off valves, relays and several peripheral device controls that enable the full operation of a turbo-molecular vacuum pump, and of gas flow and pressure controllers. All aspects of this comprehensive controller were successfully tested. The signal for the 450 Th ion (C32H66) for example increased by 123% which is a significant increase. It is obvious that correctly tuned dynamic voltages can guarantee the optimal signal for each mass.

ULP Super Regenerative Transmitter with Digital Quenching Signal Controller

This paper demonstrates an on–off keying (OOK) super-regenerative quenching transmitter operating in 402–405 MHz MICs band applications. To reduce power consumption, the transmitter is controlled by a novel digital quenching signal controller that generates a digital control signal to start transmitter operation when a baseband signal is input to the transmitter. The digital signal controller consists of an envelope detector, a comparator, and a quench timer designed using a state machine to synchronize the operation between the digital controller and the input baseband signal. The transmitter consists of a Colpitts oscillator operating in double operating frequency followed by a frequency divider by 2; this configuration reduces system area and improves phase noise and signal spectrum. The proposed transmitter is implemented using UMC 130 nm CMOS technology and a 1.2 V supply. Simulation shows that the proposed transmitter can meet MICS band mask specifications with data rates up to 1 Mbps and total power dissipation of 537 uW.

A digitally controlled adaptive LDO for power management unit in sensor node

Power management unit (PMU) is the core of the sensor node SoC to achieve high performance in wireless body area network (WBAN). This article presents a low power digitally controlled low dropout regulator (LDO) targeted for the power management unit (PMU) in a sensor node. A flash-based approach, substituting the classical error amplifier with an array of dynamic comparators, is employed in order to achieve fast transient response. The proposed LDO minimizes dynamic power consumption by employing clock gating to the comparator array through detecting any abrupt change in load demand with a modular topology. In addition, during the load transient, the proposed LDO effectively detects the voltage droop and generates a set of digital control signals to activate a specific PMOS array for coarse tuning (CT) and fine-tuning (FT). The proposed LDO is capable of handling a load step of 10 μA to 1 mA with a voltage droop of 287 mV. The LDO is implemented with 180 nm CMOS technology node, producing a regulated output voltage of 0.9 V for input voltage ranges from 0.8 V to 1.8 V. The current efficiency at 1 mA load current is 99.4%, with settling time to recover the voltage droop is 80 ns at 50 MHz clock frequency.

Experimental Investigations into the Behavior of Scaling Factors in a Fuzzy Logic Speed Control Induction Motor with Model Reference Adaptive Control

This paper presents a self-tuning fuzzy logic speed controller (FLSC) with model reference adaptive control (MRAC) for an induction motor (IM) drive system. The MRAC is examined by output scaling the factor tuner for optimum motor speed performance. A detailed investigation is carried out on the scaling factor control of the input change error and main FLSC output increment. This proposed method utilizes seven simplified rules of the 5 × 5 matrix membership functions to minimize the computational burden and memory space limitations. All simulation work is conducted using Simulink and Fuzzy Tools in the MATLAB software and the experimental testing with the aid of a digital signal controller board, dSPACE DS1103. Based on the results, the output scaling factor makes a more significant impact on the performance effect compared to the input error scaling factor. The input change error and output SF also exhibit similar behavior, indicating that a large range of UoD tuners works well in terms of capability load rejection while a small range of UoD tuners performs well in terms of rise time. The analysis includes no-load and load tests to ascertain the overshoot percentage, rise time, and settling time for transient and steady-state conditions.

A Parallel Resonant Converter Polynomial Model Implemented in a Digital Signal Controller

Due to their exceptional performance in coping with large variations in output voltage and current, parallel resonant converters (PRC) are commonly used in high-voltage applications. The incorporation of step-up transformer parasitic components as part of a power topology, on the right duty and a suitable switching frequency, determines the high efficiency and wide variety of applications with PRC. Switching losses are reduced in the same topology by tracking and running on the optimum mode for each power and voltage by a set frequency and duty. The PRC’s static model behaviors, under optimum operating circumstances, are illustrated. The equivalent polynomial model is used to quickly compute the switching frequency and duty cycle required to achieve the converter’s desired output voltage and power. The polynomial model is simple and easy to implement in any form of a digital signal controller (DSC). Normalized parameters are used to widen the operational range and generalize the model. This also offers the essential protection against current and voltage spikes. The work in progress depicts the specific procedures involved in developing a polynomial model. The normalized equations provide a graphical description of the static model, from which the graphical representation of the polynomial are derived. Hence, polynomial equations are obtained. This paper describes the PRC static model, how to convert it to a polynomial model, how to validate it with MATLAB-Simulink, how to program F28335 using Simulink, and how to use it in practice.

Maximum power extraction of hybrid photovoltaic ‐battery system with nonisolated single‐input and dual‐output DC‐DC converter: An efficient RFAMAO approach

The DC-DC converter is more significant for the integration of photovoltaic (PV) and battery. The design of the power converter is high complexity, because of the nonlinear characteristics, like supply voltage variations, switches, load current variations, and parasitic component fluctuation. This article proposes an efficient approach for increasing the maximum power of PV system and system efficiency. The proposed approach is the consolidation of Random Forest Algorithm (RFA) and Mexican Axolotl Optimization (MAO), hence it is called RFAMAO approach. The proposed approach utilized the single-input and dual-output boost converter to implement the maximum power point tracking of the system that improves the lesser voltage input power source, controllable higher voltage direct current bus and middle voltage output terminals. RFA is used to deal with the uncertainty caused by climate change. MAO is utilized to tune the control parameter of the system. The voltage-mode controlling strategy among the PV, battery, and standalone DC load depending on Digital Signal Processing and Control Engineering (DSPACE) is utilized for uninterruptible power flow management and constant DC load voltage maintenance. The proposed approach is implemented in MATLAB/Simulink, and its efficiency is compared with existing approaches. The oscillation around maximum power point (MPP) for case 1 of RFAMAO, modified shuffled frog leaping algorithm with fuzzy logic (MSFLA-FLC), fuzzy logic, and perturb and observe (P&O) is 2.69, 7.31, 20.54, and 29.12 W. The oscillation around MPP for case 2 of RFAMAO, MSFLA-FLC, fuzzy logic, and P&O is 2.57, 8.34, 18.56, and 27.65 W.

A Speed Range Extension Scheme for Scalar-Controlled Open-End Winding Induction Motor Drives

This articleproposes a new control scheme for extension of speed range of dual inverter fed induction motor drives with open-end stator windings. One of the inverters connected to one end of the stator windings is fed by a dc power source whereas the inverter connected to the other end of the windings is fed by a capacitor. The control scheme ensures that only active power required by the drive is supplied by the inverter fed by dc power source and the reactive power alone is provided by the capacitor fed inverter. The modulation index of the capacitor fed inverter is varied to provide higher voltage to the motor at higher speeds keeping the capacitor voltage constant, thereby facilitating operation above base speed without field weakening. An alternative scheme in which the capacitor voltage is allowed to vary while keeping the modulation index of the capacitor fed inverter at its maximum value is also presented in this article. The proposed schemes, based on constant v/f ratio control, are simple compared to the existing schemes. Validation of the proposed schemes is carried out under transient and steady state operating conditions by extensive simulation using PLECS software. Experimental verification is also carried out on a laboratory prototype using a digital signal controller for implementation of the control scheme.

A Five-Level Torque Controller Based DTC Scheme for Open-End Winding Five-Phase IM Drives With Single DC Source and Auxiliary Plane Harmonic Elimination

This article presents a new five-level torque hysteresis based direct torque control scheme for dual inverter fed five-phase induction motor drives with open-end stator windings. Three voltage levels required to implement the five-level torque hysteresis controller are generated by combining the appropriate voltage vectors of the two inverters. The proposed scheme ensures that the harmonic voltages in the nontorque producing auxiliary plane are nullified in every switching period. Since the switching voltage vectors are realized using adjacent and nonadjacent line voltages, the magnitude of the voltage appearing across the windings is much higher compared to the conventional star connected five-phase drive, for the same dc link voltage. This feature reduces the dc link voltage requirement substantially for a given motor voltage. The switching scheme employed prevents circulation of common mode currents even when a common dc source is used for feeding both inverters. The proposed scheme is experimentally verified on a five-phase induction motor drive with open end stator windings. The control scheme is implemented using TMS320F28335 digital signal controller.