A short predictive Model Predictive Control (MPC) approach for hybrid characteristics analysis in DC-DC converter

Historically, the MPC has been successfully applied in drives system for over a decade. Furthermore, the DC-DC converter naturally deals with high switching phenomenon that contributes to the challenging in control approach. Its operation conventionally associated with PI/PID controller in order to meet the desired output. However, the PI/PID controller lacking in getting a good transient response since this controller highly depends on the controller gains. Recently, an advanced controller has been proposed in the literature for the purpose to enhance the DC-DC converter performance. Hence, in this thesis, the short prediction horizon of MPC using search tree optimization that generates low switching states phenomenon is proposed. The MPC algorithm is developed based on the hybrid characteristic signals from the DC-DC converter. The load changes due to the increasing or decreasing the loads (could be happened of heating effect) will affect the tracking of the output voltage. The Kalman Filter (KF) is used for load estimation for smoothing and tracking the output voltage. The performance of short prediction horizons is being compared to PI controller in terms of transient response during the start-up scenario. The results show that the proposed controller has a better response than PI controller, which is the overshoot has been reduced to more than 50% and the settling time more faster about 25% than PI controller during start-up scenario. Therefore, this control approach for DC-DC buck converter has produced the promising output transient performance when compared with the conventional PI controller while also minimizing the switching sequence phenomenon

Nonlinear Cascaded Control for a DC-DC Boost Converter

The Boost Converter is a type of DC-DC converter that operates using switching techniques and is designed to elevate the voltage level. This paper presents a cascaded control for a boost converter to ensure that the inductor current and output capacitor voltage remain in a safe operating zone. Ensuring safe operating conditions and stable closed-loop poles is crucial because it guarantees that both current and voltage remain within the designated operating range. This preventive measure prevents any damage to components like capacitors (C), inductors (L), and switches. Unstable operation, on the other hand, could lead to oscillations and an undesirable increase in the amplitude of current and voltage, posing a risk to all components involved. The research contribution involves an investigation of cascaded control, utilizing power and energy concepts due to their advantageous effects on system performance and design. By implementing nonlinear controllers based on a large-signal averaged model, the closed-loop poles remain independent of operating points, eliminating the need for small-signal linearization. Small-signal linearization makes the controlled system dependent on the operating point. Two controllers are introduced based on power and energy concept, which is easy to understand. The potential practical application of the proposed cascaded control approach is in high-power applications. Tracking the energy stored in the output capacitor is first investigated to validate the proposed control scheme by varying the output voltage reference from 32 V to 50 V. Then, the regulation of the energy voltage is explored by varying the load resistance for the output voltage at 50 V. Both are done using a switched model using MATLAB/Simulink software. Simulation results are given to demonstrate the effectiveness of the proposed method. The key metrics used to assess the effectiveness of the proposed control scheme are the undershoot voltage and robustness. The results show that the studied system's tracking, regulating operations and robustness properties are as expected. The proposed method faces a challenge with the number of sensors required. To address this, observers can be utilized to reduce sensor usage while maintaining measurement accuracy. The proposed method can be applied to other power electronic systems

Nonlinear Analysis and Control of Interleaved Boost Converter Using Real-Time Cycle to Cycle Variable Slope Compensation

Switched-mode power converters are inherently nonlinear and piecewise smooth systems that may exhibit a series of undesirable operations that can greatly reduce the converter's efficiency and lifetime. This paper presents a nonlinear analysis technique to investigate the influence of system parameters on the stability of interleaved boost converters. In this approach, Monodromy matrix that contains all the comprehensive information of converter parameters and control loop can be employed to fully reveal and understand the inherent nonlinear dynamics of interleaved boost converters, including the interaction effect of switching operation. Thereby not only the boundary conditions but also the relationship between stability margin and the parameters given can be intuitively studied by the eigenvalues of this matrix. Furthermore, by employing the knowledge gained from this analysis, a real-Time cycle to cycle variable slope compensation method is proposed to guarantee a satisfactory performance of the converter with an extended range of stable operation. Outcomes show that systems can regain stability by applying the proposed method within a few time periods of switching cycles. The numerical and analytical results validate the theoretical analysis, and experimental results verify the effectiveness of the proposed approach

Sliding Mode Control of Buck Converter

DC-DC converters are used to convert DC voltage from one level to other. These converters are drastically used in industry as well as in research. One of the main limitations of these converters is unregulated supply of voltage and current. To overcome these problems there are various control techniques. This paper presents two such methods. This paper compares dynamic performance of buck Converter using PID controller and Sliding mode controller. Simulation of PI and Sliding mode control of Buck Converter is carried out in MATLAB SIMULINK

Power Electronics and Energy Management for Battery Storage Systems

The deployment of distributed renewable generation and e-mobility systems is creating a demand for improved dynamic performance, flexibility, and resilience in electrical grids. Various energy storages, such as stationary and electric vehicle batteries, together with power electronic interfaces, will play a key role in addressing these requests thanks to their enhanced functionality, fast response times, and configuration flexibility. For the large-scale implementation of this technology, the associated enabling developments are becoming of paramount importance. These include energy management algorithms; optimal sizing and coordinated control strategies of different storage technologies, including e-mobility storage; power electronic converters for interfacing renewables and battery systems, which allow for advanced interactions with the grid; and increase in round-trip efficiencies by means of advanced materials, components, and algorithms. This Special Issue contains the developments that have been published b researchers in the areas of power electronics, energy management and battery storage. A range of potential solutions to the existing barriers is presented, aiming to make the most out of these emerging technologies

Electronic operation and control of high-intensity gas-discharge lamps

The ever increasing amount of global energy consumption based on the application of fossil fuels is threatening the earth’s natural resources and environment. Worldwide, grid-based electric lighting consumes 19 % of total global electricity production. For this reason the transition towards energy efficient lighting plays an important environmental role. One of the key technologies in this transition is High-Intensity Discharge (HID) lighting. The technical revolution in gas-discharge lamps has resulted in the highlyefficient lamps that are available nowadays. As with most energy efficient light solutions, all HID lighting systems require a ballast to operate. Traditionally, magnetic ballast designs were the only choice available for HID lighting systems. Today, electronic lampdrivers can offer additional power saving, flicker free operation, and miniaturisation. Electronic lamp operation enables additional degrees of freedom in lamp-current control over the conventional electro-magnetic (EM) ballasts. The lamp-driver system performance depends on both the dynamics of the lamp and the driver. This thesis focuses on the optimisation of electronically operated HID systems, in terms of highly-efficient lamp-driver topologies and, more specifically, lamp-driver interaction control. First, highly-efficient power topologies to operate compact HID lamps on low-frequency-square-wave (LFSW) current are explored. The proposed two-stage electronic lamp-driver consists of a Power Factor Corrector (PFC) stage that meets the power utility standards. This converter is coupled to a stacked buck converter that controls the lamp-current. Both stages are operated in Zero Voltage Switching (ZVS) mode in order to reduce the switching losses. The resulting two-stage lamp-drivers feature flexible controllability, high efficiency, and high power density, and are suitable for power sandwich packaging. Secondly, lamp-driver interaction (LDI) has been studied in the simulation domain and control algorithms have been explored that improve the stability, and enable system optimisation. Two HID lamp models were developed. The first model describes the HID lamp’s small-signal electrical behaviour and its purpose is to aid to study the interaction stability. The second HID lamp model has been developed based on physics equations for the arc column and the electrode behaviour, and is intended for lampdriver simulations and control applications. Verification measurements have shown that the lamp terminal characteristics are present over a wide power and frequency range. Three LDI control algorithms were explored, using the proposed lampmodels. The first control principle optimises the LDI for a broad range of HID lamps operated at normal or reduced power. This approach consists of two control loops integrated into a fuzzy-logic controller that stabilises the lamp-current and optimises the commutation process. The second control problem concerns the application of ultra high performance (UHP) HID lamps in projection applications that typically set stringent requirements on the quality of the light generated by these lamps, and therefore the lampcurrent. These systems are subject to periodic disturbances synchronous with the LFSW commutation period. Iterative learning control (ILC) has been examined. It was experimentally verified that this algorithm compensates for repetitive disturbances. Third, Electronic HID operation also opens the door for continuous HID lamp dimming that can provide additional savings. To enable stable dimming, an observer-based HID lamp controller has been developed. This controller sets a stable minimum dim-level and monitors the gas-discharge throughout lamp life. The HID lamp observer derives physical lamp state signals from the HID arc discharge physics and the related photometric properties. Finally, practical measurements proved the proposed HID lamp observer-based control principle works satisfactorily

Sliding Mode Control of Buck Converter

DC-DC converters are used to convert DC voltage from one level to other. These converters are drastically used in industry as well as in research. One of the main limitations of these converters is unregulated supply of voltage and current. To overcome these problems there are various control techniques. This paper presents two such methods. This paper compares dynamic performance of buck Converter using PID controller and Sliding mode controller. Simulation of PI and Sliding mode control of Buck Converter is carried out in MATLAB SIMULINK