Digital Signal Processor Control Research Articles

Artificial neural network based decentralized current-sharing control for parallel connected DC-DC converters in DC microgrid application

To create a non-interrupted, economical and reliable direct current (DC) microgrid, multiple DC-DC converters can be connected in parallel. Current sharing among these multiple converters becomes essential for proper operation of the system. This study proposes an artificial neural network (ANN) based control technique for parallel connected DC-DC boost converters which ensures accurate current sharing according to the specified maximum limits. Levenberg-Marquardt algorithm-based ANN network is used to reduce the training time and, also to achieve near ≈ 100 % accuracy of the training data. ANN control provides better voltage regulation, accurate current sharing unlike the conventional proportional-integral (PI) based control which faces issues such as inaccurate current sharing, high transient, peak overshoots and steady state error during sudden change in the system. The efficient functioning of the proposed control method is verified by simulating two parallel connected DC-DC converters using MATLAB/Simulink. A hardware prototype of converters rating ≈ 250 W using TMS320F28379D Digital signal processor controller is also developed to verify the performance and effectiveness of the ANN based control in comparison to PI based technique. The ANN based technique is faster to achieve the reference voltage, and the peak overshoot is approximately 75 % lesser than the PI based control.

Sensor Fusion-Based Pulsed Controller for Low Power Solar-Charged Batteries with Experimental Tests: NiMH Battery as a Case Study

Solar energy is considered the major source of clean and ubiquitous renewable energy available on various scales in electric grids. In addition, solar energy is harnessed in various electronic devices to charge the batteries and power electronic equipment. Due to its ubiquitous nature, the corresponding market for solar-charged small-scale batteries is growing fast. The most important part to make the technology feasible is a portable battery charger and the associated controllers to automate battery charging. The charger should consider the case of charging to be convenient for the user and minimize battery degradation. However, the issue of slow charging and premature battery life loss plagues current industry standards or innovative battery technologies. In this paper, a new pulse charging technique is proposed that obviates battery deterioration and minimizes the overall charging loss. The solar-powered battery charger is prototyped and executed as a practical, versatile, and compact photovoltaic charge controller at cut rates. With the aid of sensor fusion, the charge controller is disconnected and reconnects the battery during battery overcharging and deep discharging conditions using sensors with relays. The laboratory model is tested using a less expensive PV panel, battery, and digital signal processor (DSP) controller. The charging behavior of the solar-powered PWM charge controller is studied compared with that of the constant voltage–constant current (CV–CC) method. The proposed method is pertinent for minimizing energy issues in impoverished places at a reasonable price.

Implementation of Shunt Active Power Filter Using DSP Controller Based on Synchronous Reference Frame for Harmonic Mitigation

This research paper introduces the concept of a shunt active power filter (SAPF) that leverages synchronous-reference-frame (SRF) theory to mitigate harmonics in the power system. The SAPF works by injecting a compensating current at the point of common coupling (PCC) to counteract the harmonics in the line and restore sinusoidal current waveforms. It employs a three-phase current-controlled voltage source inverter (VSI) with a DC link capacitor for active filtering. An SRF algorithm is designed for a low-voltage laboratory prototype utilizing the TMS320F28335 Digital Signal Processor (DSP). The experimental findings affirm that the control strategy effectively aligns with the recommended harmonic standard limits of IEEE 519-1992.

Design Implementation of a Logger-Based Digital Thermometer

LM35 temperature sensor is a widely used 3-terminal sensor known for its precise temperature measurement capabilities without the need for external calibration circuitry. With a sensitivity of 10mV/°C, it operates within a temperature range of -55°C to 150°C, with an error margin of 0.5°C. This paper presents the development and testing of a logger-based digital thermometer using LM35 sensor, integrated with a dsPIC30F4013 digital signal processing controller, an LCD, a real-time clock (DS1307), and other essential components. The methodology involves the analysis of the sensor's sensitivity and its response under both stress and non-stress temperature conditions. The findings indicate that the sensor's output closely follows the theoretical sensitivity, with a negligible offset, ensuring accurate temperature measurements. Comparative analysis with a standard laboratory thermometer suggests that the digital sensor provides superior precision, with an error margin of ±0.01°C. The results confirm LM35's suitability for accurate ambient temperature monitoring and validation of environmental temperature fluctuations.

Enhanced Volts-per-Hertz Sensorless Starting of Permanent Magnet Motor with Heavy Loads in Long-Cable Subsea Applications

Permanent magnet (PM) motors are gaining prominence in subsea applications such as drilling, pumping, and boosting for oil and natural gas extraction. These motors are gradually replacing traditional induction motors. However, starting and operating PM motors at low speeds under heavy loads poses significant challenges. This is because of unknown initial rotor positions and resistive voltage drops due to the presence of a sinewave filter, transformer, and long cable. An unknown rotor position may result in temporary reverse speed, which may cause a loss of synchronism; therefore, initial rotor position estimation is preferable. Additionally, addressing the voltage drop issue requires careful voltage compensation to avoid transformer core saturation. In this paper, an enhanced V/Hz starting of a PM motor is proposed with initial position detection (IPD) and voltage compensation to start the motor reliably with a heavy load. The proposed control method is verified with controller hardware in the loop (C-HIL) real-time simulation using a Typhoon HIL-604 emulator and a Texas Instruments TMS320F28335 digital signal processor (DSP) control card.

Adaptive feedback control of stability in an axial compressor with circumferential inlet distortion

The adaptive feedback control of stability with circumferential inlet distortion has been experimentally investigated in a low-speed, axial compressor. The flat-baffles with different span heights are used to simulate different distorted inflow cases. Compared with auto-correlation and root-mean-square analysis, cross-correlation analysis used to predict early stall warning does not depend on the distortion position. Hence, the cross-correlation coefficient was used to monitor the stable status of the compressor and provide the feedback signal in the active control strategy when suffering from different distortions. Based on the stall margin improvement of tip air injection obtained under different distorted inflow cases and the sensitivity analysis of cross-correlation coefficients to injected momentum ratios, tip air injection was adopted as the actuator for adaptive feedback control. The digital signal processing controller was designed and applied to achieve adaptive feedback control in distorted inflow conditions. The results show that the adaptive feedback control of air injection nearly achieves the same stall margin improvement as steady air injection under different distortion intensities with a reduced injection mass flow. Thus, the proposed adaptive feedback control method is ideal for the engine operation with circumferential distorted inflow, which frequently occurs in flight.

Simulation and implementation of a harmonics suppression technique for a single-phase full-bridge converters

ABSTRACT This paper presents a harmonic suppression technique for a single-phase full-bridge converter, and the mathematical principles underlying a modified PWM technique are discussed. To verify the effectiveness of the proposed technique, voltage and current sensor circuits in a single-phase full-bridge converter connected to a digital signal processor controller with an analog-to-digital converter were analyzed experimentally. The output voltage harmonics of the converter were examined, and the frequency spectra of the output voltage were analyzed. Furthermore, a digital control system with a TMS320F2808 digital signal microcontroller was realized. The experimental results verified the effectiveness of the proposed technique in suppressing low-frequency harmonic in a prototype of a converter.

SR Motor T-I Characteristics Performance Simulation Validation through Experimental Results

This article presents T-I (Torque–Current) characteristics performance of switched reluctance motor (SRM), simulation validation through experimental results. SRM has a simple construction, high fault tolerance capability, reliability, and low cost considered for the study. It works on the principle of reluctance. The simulation using MATLAB/SIMULINK for 8/6 SRM and experimentation tests in the laboratory is essential to find performance. Advance speed control technique of SRM drive using Digital Signal Processor (DSP-28335) controller and hardware setup for experimentation is utilized, for testing the performance. SRM is applicable in automation, electric vehicle, and industry. The characteristics study is a very important need in all applications. The simulation model for SRM is built in MATLAB/SIMULINK using proportional-integral controller. Experiments are conducted in the laboratory on SRM by load tests with a digital storage oscilloscope. Test data along with waveform are recorded for simulation and experimentation. Torque–Current characteristics performances are plotted. Finally, all results of both experimental and simulation are validated and presented. T-I characteristics of SRM are compared in both simulation and experimentation are very close to comparable.

Power Quality Control System of High-Power-Density Switching Power Supply for Green Environment

There is higher harmonics and electromagnetic interference caused by high-power-density switching power supply during high-frequency and normal operations which affects power quality of switching power supply and also impacts the environment. To solve this problem, this paper proposes a dual digital signal processor (DSP) controller suitable for unified power quality regulators and designs high-power-density switching power supply control system for promoting green environment. The overall structure of the system is divided into two parts, the power main circuit and the control circuit. In the main power circuit, the electromagnetic interference (EMI) filter is used to filter the input AC voltage and convert it into a stable DC voltage. A high-frequency inverter is used to invert the DC voltage into a high-frequency AC voltage to achieve harmonic control and reactive power compensation. In the control circuit, dual DSP controller is used to improve real-time detection, control of the output voltage, and current and driver temperature of the high-power-density switching power supply, while high-precision analysis and processing system collect different information and then achieve the power quality control of the switching power supply based on system software to keep this environment green. The experimental results suggest that the harmonic content of the experimental objects controlled by the system is reduced by 16.7% compared with the existing power quality control and the absolute error of the system is less than 0.02 V which improves the de-noising performance. The power generation systems require that the consumption of natural resources and renewable energy solutions can assist in saving the natural resources.

A PLL-less Vector Control technique for the single-phase Grid connected inverters

The control of single-phase Grid connected inverters by Vector Current Control Direct Quadrature (VCC DQ) method is a well-known technique. However, the presence of a Phase-Locked Loop (PLL) affects the dynamic response of the system. This paper proposes a PLL-less Vector Control (PLVC) method in which a single-phase Grid connected inverter is controlled without any PLL. Hence it reduces the complexity and computational burden during implementation on the Digital Signal Processor (DSP) controller as well as the natural coupling of PLL and current controller. The mathematical modeling and controller design for the PLVC method is described. A 5 kW single-phase Grid connected inverter simulation model and a 150 W hardware prototype with TI F28379D processor are developed and tested under steady-state at rated power condition and dynamic conditions like instant variation in the reference powers. Also, the robustness of the controller is tested under adverse conditions voltage sag, swell at the instant of distinct phase angles and frequency deviation also.

New perturb and observe algorithm based on trapezoidal rule: Uniform and partial shading conditions

This paper proposes a new version of the perturb and observe (P&O) algorithm which is able to recognize the global maximum power point (GMPP) among the multiple maximum peaks that exist in the P-V curve under the effect of the partial shading condition (PSC). For the first time, Trapezoidal rule concept is employed in P&O approach as a new consideration in the tracking process to calculate the best path for precisely tracking the GMPP. The new algorithm allows the search to continue until the extremum maximum is identified among numerous local maximums, rather than being imprisoned at one of the local maximums as is the case with the standard algorithm. Furthermore, the algorithm is able to achieve the MPP efficiently under the presence of rapid and abrupt changes in irradiation levels. The proposed Trapezoidal rule based P&O algorithm is evaluated under three conditions: (1) under uniform irradiance (2) under shading conditions and (3) under sudden and step changes in irradiation levels as well as the transition between shading patterns. The feasibility and effectiveness of the suggested algorithm, as well as the well-designed boost converter, are validated using two different methodologies: a simulation model in MATLAB/Simulink and hardware implementation by the (TMS320F28335) digital signal processing controller. Both simulation and hardware results confirm that the proposed algorithm provides excellent efficiency of 100% and 99.6% respectively. The GMPP is achieved within less than 100 ms, which is extremely advantageous tracking time, that avoids the power losses. In addition, the minimal steady-state oscillation is shown, with the desired level of simplicity without the need to complicated computations or random particles.

Optimized design of battery pole control system based on dual-chip architecture.

At present, the global demand for lithium batteries is still in a high growth state, and the traditional lithium battery pole mill control system is still dominated by ARM (Artificial Intelligence Enhanced Computing), DSP (Digital Signal Processing), and other single-chip control methods. There are problems such as poor anti-interference ability and insufficient real-time online analysis of production data. This paper adopts the dual-chip control system architecture based on "ARM+DSP", starting from the mechanical characteristics and operating signal features of the pole mill. The hardware system adopts a three-unit joint control hardware structure, which separates the control unit from the data processing unit and improves the operation of the system. The software system adopts fuzzy PID algorithm to realize deflection control and tension control, and verifies that the Fuzzy PID (Proportion Integration Differentiation) control algorithm can effectively improve the anti-interference ability of the deflection system and tension system. The results show that the data loss rate is low with the SPI communication between DSP and ARM. The tension error of the "ARM+DSP" control system does not exceed 5%, and the deviation of the correction band is within ±4mm. The dedicated dual-chip hardware architecture effectively improves the robustness and operation efficiency of the pole mill, solves the problem of low tension control accuracy, and provides a theoretical basis for the application of the dual-roll mill.

DSP Processer-in-the-Loop Tests Based on Automatic Code Generation

The digital signal processing (DSP) processor-in-the-loop tests based on automatic code generation technology are studied. Firstly, the idea of model-based design is introduced, and the principle and method of embedded code automatic generation technology are analyzed by taking the automatic code generation of the DSP control algorithm for pulse width modulation (PWM) output as an example. Then, the control system model is established on MATLAB/Simulink. After verifying the model through simulation, the target board platform is established with DSP as the core processor, and the automatically generated code is tested by the processor-in-the-loop (PIL). The results show that the technology greatly shortens the development cycle of the project, improves the robustness and consistency of the control code, and can be widely used in the complex algorithm development process of the controller, from intelligent design and modeling to implementation.

Battery energy storage system with functions of wide AC voltage range and battery current filtering

ABSTRACT This paper develops a power conversion interface for a battery energy storage system (BESS). The power conversion interface is composed of a bidirectional DC-DC power converter and a three-port DC-AC power converter, and it has the functions of wide AC voltage range and battery current filtering. The three-port DC-AC power converter has a high-voltage DC port, a low-voltage DC port and an AC port. The high-voltage DC port and low-voltage DC port are, respectively, connected to the output of the DC-DC power converter and the battery set, and the AC port is connected to the grid. The three-port DC-AC power converter generates a five-level voltage or a three-level AC voltage at the AC port according to the amplitude of grid voltage. The bidirectional DC-DC power converter has two functions. One is to generate a higher DC voltage to the high-voltage DC port, and the other is to perform a DC active filter function for attenuating the low-frequency ripple of the charging/discharging current for the battery set. All or part of the charging/discharging power for the battery set is only processed by the three-port DC-AC power converter, which can improve the efficiency of the BESS. A hardware prototype with a digital signal processor controller is developed to verify the performance of the developed power conversion interface for the BESS.

Programmable smart fast gas chromatograph and open probe controller

Today, labs that carry out chemical analyses for regulation, food safety, health, forensics, or even security purposes are looking for ways to accelerate the analytical process. Slow procedures are costly because the necessary instruments are expensive and require maintenance and a highly trained staff to operate them. One of the more ubiquitous instruments in such labs is a Gas Chromatograph (GC), which accepts a solution and outputs each of the compounds within it in a gaseous form, one by one to be further analyzed and identified, usually by a Mass Spectrometer (MS). This separation process in a GC can be rather time-consuming, partly due to the slow heating and cooling of the GC column through which the compounds move, which happens inside a box-shaped oven.This paper describes a controller developed for a unique Open Probe Fast GC instrument that enables, among other things, high-speed and controlled heating and cooling of a gas-carrying capillary transfer line. Fast heating is achieved by precisely controlling the electrical current flowing through the small inner-diameter steel tube through which the GC column passes. The fast cooling occurs by exposing the low-mass heated tube to room temperature, along with the assistance of a simple fan that carries the heated air away. This technology also supports control of other system parts, including a unique quick sampling device called an Open Probe that allows for an even faster analysis cycle. Our design is based entirely on a digital signal processor (DSP) and digital control. The use of pulse width modulation (PWM) control enables a compact and efficient system.

Development and experimental realization of an adaptive neural-based discrete model predictive direct torque and flux controller for induction motor drive

This paper develops a neural network-based discrete predictive direct torque and flux control (NNPDTFC) for induction motor drive with the space vector modulation (SVM) technique. Moreover, this SVM technique with NNPDTFC is implemented to activate the inverter in the two-level operation and the performance is compared with the conventional PI direct torque and flux control (PIDTFC) technique. The PSO based model predictive control incorporated with the neural network is developed here in the NNPDTFC and is analyzed using MATLAB software. Disturbance reduction, simple control, and real-time implementation are the major features of NNPDTFC and it also enhances the transient performance of the motor drive by reducing settling time and peak overshoot. In addition, the flux and the torque ripples are significantly improved using the proposed NNPDTFC technique which is extensively used for the fast dynamic response of the induction motor drives as compared to PIDTFC. In order to show the potentiality of the proposed controller, a prototype controller is developed and validated with the laboratory setup and the control signals are generated for both NNPDTFC and PIDTFC using a low-cost Digital signal processor (DSP) controller which is fed to the induction motor of 3.7 kW capacity in the real-time platform. It is observed that the results with NNPDTFC are not only found to be extremely satisfactory even with the system and parameter uncertainties and external load perturbations but also, it produces enhanced dynamic as well as steady-state performance along with the reduced ripples in the signal flux, torque, and current compared to that of PIDTFC.

Second‐order SMO‐based sensorless control of IM drive: experimental investigations of observer sensitivity and system reconfiguration in postfault operation mode

In normal operation mode, sensorless speed-controlled motor drives should be more reliable, less expensive and less bulky than their counterparts with a speed sensor. The sensorless drive structure allows avoiding the electromagnetic and vibratory sensitivity of the mechanical sensor, the additional connecting circuits, additional space for the sensor, its price and maintenance requirements. However, in postfault operation mode, the robustness of speed sensorless control strategies has been poorly addressed in the study. Accordingly, this study deals with an experimental study of the robustness and the availability of speed-controlled induction motor (IM) drives without speed sensor in the presence of inverter open-switches faults. For that purpose, a super twisting algorithm-based observer for motor speed estimation is proposed for experimental investigation. Experimental results are performed upon 3-kW IM drive by using dSPACE digital signal processing controller board. Experimental investigations evaluate the performances of the method used for the control without speed sensor in prefault, postfault and regeneration operation modes.

Voltage Regulation of Hydro Standalone 1-Φ Micro Grid using Fuzzy Logic Based Adaptive Sliding Mode Control Algorithm

This paper presents an adaptive sliding mode control (ASMC) of an improved power quality standalone single phase microgrid system. The proposed microgrid system integrates a governor-less micro-hydro turbine driven single- phase two winding self-excited induction generator (SEIG) with a wind driven permanent magnet brushless DC (PMBLDC) generator, solar photo-voltaic (PV) array and a battery energy storage system (BESS). These renewable energy sources are integrated using only one single-phase voltage source converter (VSC). The ASMC based control algorithm is used to estimate the reference source current which controls the single-phase VSC and regulates the voltage and frequency of the microgrid in addition to harmonics current mitigation. The proposed ASMC estimates the reference real and reactive powers of the system, which is adaptive to the fluctuating loads. The sliding mode control is used to estimate the reference real power of the system to maintain the energy balance among wind, micro-hydro, solar PV power and BESS, which controls the frequency of standalone microgrid. The proposed microgrid is implemented in real time using a DSP (Digital Signal Processor) controller. Test results of proposed microgrid shows that the grid voltage and frequency are maintained constant while the system is following a sudden change in loads and under intermittent penetration of wind and solar energy sources.

Submodule Capacitance Monitoring Strategy for Phase-Shifted Carrier Pulsewidth-Modulation-Based Modular Multilevel Converters

Capacitance monitoring is one of the important issues for a modular multilevel converter (MMC) to obtain high reliability. Since pulsewidth modulation is usually implemented in the field-programmable gate array (FPGA), produced precise switching states in the FPGA cannot be directly accessed by the top digital signal processor (DSP) controller, which poses challenges to the existing capacitance monitoring methods based on precise switching states of the MMC. This article presents a submodule (SM) capacitance monitoring strategy for the MMC with a simple algorithm, where the fundamental frequency components of the SM capacitor voltage and current are extracted to estimate the SM capacitance based on reference, but not the precise switching states. The proposed scheme not only simplifies the implementation and calculation, but also avoids control limitations and heavy communication burden between the DSP and the FPGA. Besides, the proposed strategy effectively eliminates noise impact from sensors and increases accuracy. Simulation and experimental studies are implemented, and the results confirm the effectiveness of the proposed strategy.

A Multi-Level Power Converter Interface for a Battery Energy Storage System

— This study proposes a multi-level power converter for a battery energy storage system (BESS) with bidirectional power flow. The multi-level power converter includes a DC-DC power converter, a selection switch set and a full-bridge inverter. The DC-DC power converter performs bidirectional power conversion and provides a DC voltage that is greater than the peak voltage of the utility. Integrating the selection switch set and the full-bridge inverter produces a five-level AC voltage that controls the real power flow and the reactive power flow between the battery set, the DC-DC power converter and the grid. Because partial power is directly processed using only the selection switch set and the full-bridge inverter, the DC-DC power converter is operated only when the grid voltage is greater than the voltage of the battery set. Therefore, the power conversion efficiency for the proposed BESS is improved. The proposed BESS uses only eight power electronic switches, so the power circuit is simplified. A hardware prototype with a digital signal processor controller is used to verify the performance of the proposed BESS. The experimental results are as expected.