Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026In-depth Analysis of the Control Unit for Multiple Voltage Rails to Drive a Variety of ICs
Yanarateş, Cağfer; Altan, Aytaç
Generating a negative output voltage rail from a positive input voltage is possible by reconfiguring an ordinary buck regulator into an inverting buck-boost (IBB) topology. Rather than operating considerations such as voltage and current stresses, the main challenge associated with this transformation arises from differences in the small-signal closed-loop characteristics. The most critical distinction is the presence of a right-half-plane (RHP) zero in the control-to-output transfer function of the IBB, which introduces non-minimum-phase behaviour, reduces the achievable phase margin, and may lead to instability and poor load transient response. For conventional PI controllers, the buck and IBB converters resulted in settling times of 5.0 ms and 6.8 ms, with overshoots of 13.65% and 8.46%, respectively, thus demonstrating the performance limitations of fixed-gain designs. As a solution, an auto-tuned PI controller with adaptive features has been proposed, which operates effectively in both the buck and IBB topologies. The proposed scheme achieves a significantly faster settling time of 2.27 ms with overshoot and undershoot below 2%, thereby ensuring superior robustness and dynamic performance compared to conventional approaches.
- MakaleYayıncıda açık erişim2026Measurement-aware zero-phase iterative learning control for robust regulation of nonideal boost converters in electric vehicle fast charging
Altan, Aytaç; Alzaidi, Mohammed S.; Yanarateş, Cağfer
Integrating battery energy storage with DC-DC boost converters for electric vehicle fast charging exposes the regulator to ageing-induced parameter drift, periodic load pulses, and, critically, the nonidealities in the output-voltage sensing chain. This paper proposes a measurement-aware, zero-phase iterative learning control scheme for robust output-voltage regulation of a nonideal boost converter whose parameters are matched to those of a commercial Texas Instruments TPS6102x battery regulator. The controller combines an inner proportional-integral stabilizing loop with an outer zero-phase learning law that updates a feedforward correction based on the sensor-captured output trajectory; a forward-backward robustness filter suppresses the amplification of measurement noise and quantization across successive trials without introducing phase lag. The averaged small-signal model is validated against a 960 kHz switched simulation, with agreement within 0.2% at the operating point and a transient-waveform correlation of 0.91, while the bandwidth limitations imposed by the lightly damped resonance and the nonminimum-phase dynamics on feedback are quantified from the loop frequency response. Because feedback alone is bandwidth-limited, the learning feedforward recovers the intrinsic converter speed for the repetitive task and reduces the periodic tracking error by more than an order of magnitude relative to a fairly tuned baseline. A bounded-error convergence theorem shows that, under real sensing, the tracking error converges to a neighbourhood whose size is proportional to the measurement-disturbance level; this is confirmed numerically, with the asymptotic error scaling approximately linearly with the noise standard deviation once the noise dominates the filter bias. Systematic sweeps of converter resolution, noise, and sensor delay show that the zero-phase measurement-aware law remains bounded where a naive learning law diverges, and a 500-sample Monte Carlo study confirms robustness to component tolerances, load variation, and parasitic aging. The primary physical task is the rejection of a repeating high-current charging pulse: over successive charging cycles the scheme reduces the periodic output-voltage sag from 35% to below 0.01%, whereas the best feedback comparator leaves a 17% residual, and the sinusoidal reference used elsewhere serves as a spectral diagnostic that isolates the feedback-bandwidth ceiling at a single known frequency. The learning law is further verified in closed loop on the cycle-by-cycle switched large-signal converter, where it converges and stays bounded. A per-unit scale-invariance analysis then establishes the conditions under which the design obtained on the low-power benchmark transfers to fast-charging power levels, as confirmed on a 400 V, 6.1 kW stage that reproduces the benchmark convergence exactly.
- MakaleAçık Erişim2025Optimizing Reflow Soldering Oven Temperature Control: A Mathematical Approach with First-Order Modelling and PI Controller Design
Altan, Aytaç; Yanarates, Cagfer
This paper presents a comprehensive analysis of the identification and control of a reflow soldering oven, with the primary goal of developing a Proportional-Integral (PI) controller to ensure precise temperature regulation and high-quality solder joints in circuit board manufacturing. The study begins by examining the generic thermal profile of a reflow soldering oven, offering insights into its temperature dynamics and control requirements. A mathematical model of the oven is derived using a first-order transfer function with transport delay, based on system response analysis. This model serves as the basis for designing and tuning the PI controller. The design process involves a systematic approach, including model validation and performance analysis under various operating conditions. The optimization of temperature control focuses on minimizing overshoot, compensating for steady-state errors, and ensuring robust responses to disturbances. Comprehensive simulations are conducted to evaluate the system's performance and stability, taking into account potential disturbances, noise, and time delays. The effectiveness of the developed PI controller is validated through comparisons with a simple Proportional (P) controller, and its accuracy is verified using the pole placement method. The results demonstrate significant improvements in temperature control, highlighting the controller's ability to precisely maintain desired thermal profiles.
- MakaleAçık Erişim2025Solving the Dynamic Stability Challenge of Automatic Gain-Controlled Phase-Locked Loops: A Robust Alternative via Enhanced SRF-PLL Design and Implementation
Yanarateş, Cağfer; Altan, Aytaç
This study presents a robust alternative to conventional phase-locked loop (PLL) architectures through the design and real-time implementation of an enhanced Synchronous Reference Frame Phase-Locked Loop (SRF-PLL) for single-phase inverter systems. Targeting the inherent dynamic stability limitations of Automatic Gain-Controlled PLLs (AGC-PLLs), the proposed SRF-PLL demonstrates superior performance in transient response and tracking accuracy. Comparative evaluations under diverse dynamic operating conditions—including phase angle jumps, voltage sags/swells, frequency steps, noise, and harmonic distortion—highlight its resilience and adaptability. Experimental results reveal a substantial improvement in dynamic response, achieving 2.5 to 6 times faster settling times depending on the operating condition. Moreover, peak-to-peak oscillations were significantly suppressed, with deviations reduced from 2° to nearly 0° under a 5 Hz frequency step scenario, even in the presence of 3rd order harmonic injection. For a 40° phase angle step, the proposed system achieves a fivefold improvement in attenuation time (0.03 s vs. 0.11 s) compared to the AGC-PLL. Under voltage sag conditions with noise and 3rd order harmonic injection, the enhanced SRF-PLL reduces the attenuation time from 0.2 s to 0.08 s. During voltage swell scenarios, it further improves the response time from 0.025 s to 0.01 s. These findings confirm the practical benefits and efficiency of the enhanced SRF-PLL for applications requiring precise and reliable phase tracking and synchronization.
- MakaleAçık Erişim2024Dc regulation and loop gain analysis of a dc-dc switch mode power supply: a case study on a synchronous pwm controlled buck converter
Altan, Aytaç; Yanarates, Cagfer
This study investigates the DC regulation of a DC-DC buck converter operating with pulse width modulation (PWM), taking into account the internal resistance of the coil and the on-resistance of the switching device. The effect of these parameters on the input/output disturbances is analyzed in continuous-conduction mode under constant frequency voltage mode control. The study also explores the effect on loop gain using the IRU3037 8-pin IC synchronous PWM controlled buck converter. The transfer function of the IRU3037 IC is derived from datasheet values using state-space averaging and AC small signal methods. A Type II compensator is then designed based on the derived transfer function. In addition, the step response characteristics of the open-loop and closed-loop circuits are investigated by time domain analysis.
- MakaleAçık Erişim2024Compact analysis of the necessity of padé approximation for delayed continuous-time models in lqr, h-infinity and root locus control strategies
Altan, Aytaç; Yanarates, Cagfer
This paper presents a comprehensive analysis of the need for the Padé approximation for continuous-time models with delays, focusing on its critical role in addressing the control challenges posed by time delays. Time delays, often referred to as dead times, transport delays or time lags, are inherent in a wide range of industrial and engineering processes. These delays introduce phase shifts that degrade control performance by reducing control bandwidth and threatening the stability of closed-loop systems. Accurate modelling and compensation of these delays is essential to maintain system stability and ensure effective control. This paper highlights the difficulties that arise when using advanced control techniques such as root locus (RL), linear quadratic regulator (LQR) and H-infinity (H_∞) control in systems with delays. Representing delays in exponential form leads to an infinite number of state problems, complicating the design and analysis of controllers in such systems. To address these challenges, the Padé approximation is proposed as an effective method for approximating time delays with rational polynomials of appropriate order. This approach allows for more accurate simulation, system analysis and controller design, thereby mitigating the problems caused by delays. The paper also provides a detailed comparative analysis between the Padé approximation and Taylor polynomials, demonstrating the superiority of the former in achieving accurate delay modelling and control performance. The results show that the use of Padé approximation not only improves the accuracy of system models, but also improves the robustness and stability of control strategies such as RL, LQR, and H_∞. These results highlight the importance of the Padé approximation as a valuable tool in the design of delay-affected control systems, offering significant advantages for both theoretical and practical applications.
- MakaleAçık Erişim2024Investigating the impact of discretization techniques on real-time digital control of DC-DC boost converters: A comprehensive analysis
Yanarateş, Cağfer; Zhou, Zhongfu; Altan, Aytaç
This paper provides a thorough comparative analysis of discretization techniques commonly utilized in digital control applications for DC-DC boost converters (DBCs). Given the crucial role of DC-DC converters in various industries such as renewable energy systems, electric vehicles, and portable electronic devices, it is imperative to optimize their performance through efficient digital control. This study aims to improve the understanding of the effects of discretization methods on control system behaviour. It investigates their impact on the performance, stability and accuracy of control algorithms in the context of DBC, using dSPACE real-time interface (RTI) and hardware-in-the-loop (HIL) simulation for validation. This approach replicates real-world conditions, allowing performance to be evaluated in a controlled environment. The analysis examines behaviour in the time and frequency domains, providing insight into the strengths and weaknesses of each method. Experimental validation using MATLAB/Simulink/Stateflow on dSPACE RTI 1007 processor, DS2004 high-speed A/D and CP4002 timing and digital I/O boards ensures that the comparative analysis provides practical benefits for DBC digital control applications.
- MakaleAçık Erişim2024A robust chaos-inspired artificial intelligence model for dealing with nonlinear dynamics in wind speed forecasting
Barış, Caner; Yanarateş, Cağfer; Altan, Aytaç
The global impacts of climate change have become increasingly pronounced in recent years due to the rise in greenhouse gas emissions from fossil fuels. This trend threatens water resources, ecological balance, and could lead to desertification and drought. To address these challenges, reducing fossil fuel consumption and embracing renewable energy sources is crucial. Among these, wind energy stands out as a clean and renewable source garnering more attention each day. However, the variable and unpredictable nature of wind speed presents a challenge to integrating wind energy into the electricity grid. Accurate wind speed forecasting is essential to overcome these obstacles and optimize wind energy usage. This study focuses on developing a robust wind speed forecasting model capable of handling non-linear dynamics to minimize losses and improve wind energy efficiency. Wind speed data from the Bandırma meteorological station in the Marmara region of Turkey, known for its wind energy potential, was decomposed into intrinsic mode functions (IMFs) using robust empirical mode decomposition (REMD). The extracted IMFs were then fed into a long short-term memory (LSTM) architecture whose parameters were estimated using the African vultures optimization (AVO) algorithm based on tent chaotic mapping. This approach aimed to build a highly accurate wind speed forecasting model. The performance of the proposed optimization algorithm in improving the model parameters was compared with that of the chaotic particle swarm optimization (CPSO) algorithm. Finally, the study highlights the potential of utilizing advanced optimization techniques and deep learning models to improve wind speed forecasting, ultimately contributing to more efficient and sustainable wind energy generation. This robust hybrid model represents a significant step forward in wind energy research and its practical applications.
- MakaleAçık Erişim2023Performance analysis of digitally controlled nonlinear systems considering time delay issues
Yanarateş, Cağfer; Okur, Serkan; Altan, Aytaç
In this paper, a comprehensive investigation into discretization, effective sample time selection considering delays in the system, and time and frequency domain analysis of a DC-DC buck converter, which plays a vital role in photovoltaic (PV) systems, is conducted to enhance the understanding of their dynamic behavior, optimize control algorithms, improve system efficiency, and ensure reliable power conversion in photovoltaic applications. To effectively address the non-linear behavior and enhance digital control of a buck converter by selecting the best sample time, several approaches can be employed. These include accurate modeling and identification of non-linear elements, development of advanced control algorithms that account for non-linearities, implementation of adaptive control techniques, and utilization of feedback mechanisms to compensate for deviations from linearity. By considering and mitigating the non-linear behavior, digital control systems can achieve improved accuracy, stability, and transient behavior in regulating the buck converter's output waveforms (voltage or current). The results of the study demonstrated that the trapezoidal integration method which is also known as bilinear approximation, or Tustin's approach outperformed other commonly used discretization methods, such as first-order hold (FOH), zero-order hold (ZOH), impulse response matching (impulse invariant), and matched pole-zero (MPZ) technique, in dual-domain (both time and frequency) analysis. The key finding highlighting the superiority of the bilinear approximation was its ability to achieve the closest match in the frequency domain bridging the continuous-time and discrete systems. This finding emphasizes the significance of the bilinear approach in preserving the frequency characteristics of the original continuous-time system during discretization. By employing this method, the discrete system closely approximated the behavior of its continuous-time counterpart, ensuring accurate frequency-domain representation.