A coupled inductor based on dual switches buck-boost converter is proposed in the article, which can be used in renewable energy applications. Wide conversion ratio can be realized by regulating turns ratio of the coupled inductor and the duty cycle. The topology has a quadratic- like voltage gain, and the low voltage stress and current stress. Combing the passive clamping circuit to recover leakage energy, the voltage spikes of power switches are suppressed, improving the efficiency. Moreover, it has the merits of continuous input current and common ground. To demonstrate the superior performances of the presented converter, the principle of operation and steady-state analysis are presented in detail. At last, a 100 W experimental prototype was designed to verify the correctness of the theoretical analysis, with a maximum efficiency of 95.7% in step-up mode and 96.8 % in step-down mode.

A document by Zhiwen Niu. Click on the document to view its contents.

In this article, we propose a fast 3D-IC floorplanning method for hard macro-blocks that includes a thermal management scheme. It applies a genetic algorithm constituted by an optimal combination of crossover and mutation operations to identify the optimal solution for design variables, namely, total wire length, number of through-silicon vias (TSVs), and maximum average layer power density. The proposed method additionally makes use of a unique TSV placement scheme that arranges TSVs next to their respective functional blocks. To enable efficient heat transmission to the ambient environment, layers with higher power densities are placed closer to the heat sink. The proposed 3D-IC floorplanning approach provides the fewest TSVs, the lowest peak temperature, and promising values of wire length within the least amount of computation time. Compared to the recent fast thermal analysis for fixed-outline 3D-floorplanning, it generates 13.14% shorter wire length, 39.27% lower peak temperature, and 34.35% lesser number of TSVs on average with significant improvement in computation time, while analyzing GSRC thermal benchmark circuits.

It is well-known that DC-DC boost converters are cascaded with DC-AC inverters for grid connection of the photovoltaic (PV) systems. In the traditional control approaches, the mentioned DC-DC and DC-AC converters are controlled separately to facilitate the controller design problem. However, from the controller design viewpoint, the overall structure of the grid connected PV generator is a multi-input multi-output (MIMO) system. The duty-cycle of the DC-DC converter and Inverter modulation index are the control inputs and on the other hand, generated photovoltaic DC power, and exported power to the grid are control outputs. Moreover, the inverter DC link voltage should be stabilized by the closed-loop controller as well as an internal control output. If controllers are designed separately, it means that the interaction between DC-DC and DC-AC controllers isn’t considered accurately and since the isolated models of DC-DC converter and DC-AC inverter are extracted based on some approximated assumptions, separate controller design cannot guarantee stability and robustness of the whole system in a wide range of operation. To cope with these problems, in this paper, a novel MIMO sliding mode controller (SMC) is developed for comprehensive closed-loop control of the DC-DC boost converter cascaded with a single-phase DC-AC grid connected photovoltaic inverter. In the proposed approach, the dynamic model of whole system is developed comprehensively at first and then a unique MIMO controller is designed to control both DC-to-AC and DC-to-DC converters together. To cope with the nonlinear characteristic of the system and uncertainty of model parameters in a wide range, a fixed-frequency SMC is developed using the comprehensive state space model of the closed loop system. In the proposed MIMO-SMC controller, the AC power (which is exported to the grid) and operating point of the PV source are controlled via inverter modulation index and duty cycle of the DC-DC boost converter respectively. Another major advantage of the proposed system is mitigating the non-minimum phase characteristic of the boost converter through the indirect control of inverter DC link capacitor. To evaluate the performance of the designed control system, simulation results are compared with a standard linear PI controller. It is shown that the developed system has zero steady-state error and enjoys faster dynamic response during the start-up and step changes of AC and DC current references. Moreover, it can maintain the stability of closed-loop systems in a wide range of operations.

By integrating the Four Switch Buck-Boost (FSBB) PFC and full-bridge LLC resonant converter, a novel single-stage FSBB-LLC AC-DC converter is proposed. Moreover, a dual-loop feedback control strategy based on PFM/PWM hybrid modulation is proposed for obtaining the desired bus voltage and stable output voltage. The bus voltage feedback loop is utilized to regulate the bus voltage by selecting the boost or buck-boost mode; the output voltage feedback loop is employed to stabilize the output voltage by adjusting the switching frequency or phase shifting angle. Furthermore, an optimal parameter design based on power balance principle is also derived. The experimental results of an 85~300V input, 12V/25A output prototype demonstrate that: (1) low and narrow bus voltage of 240~340V is achieved under the entire input and output condition; (2) the LLC cell operates as a DCX converter over the whole load range as the input voltage exceeds 120V; (3) the output voltage is well regulated even under the no-load condition; (4) ZVS feature for the shared main switches is still maintained; (5) a peak efficiency of 90.9% and PF values above 0.987 are achieved.

Multilevel inverters (MLIs) have attracted the attention of researchers for their needs in industrial applications, renewable energy systems, and electric vehicles. MLIs require a large number of power electronic components to synthesize higher levels at the output voltage. However, overuse of power electronic devices increases the complexity, losses, and cost of MLIs. In this study, a new MLI has been proposed with a reduced number of power switches. The basic unit of the proposed MLI comprises only three independent DC sources and ten switches (eight unidirectional, and two bidirectional) to produce 21 levels at the output voltage waveform. The nearest level control (NLC) modulation method has been used to produce gate pulses. Furthermore, three extension topologies have been proposed to generate a higher number of levels and the extension parameters have been compared with recently introduced and conventional topologies. The comparative study shows that the proposed MLI topology requires fewer components in terms of power electronics parameters than the others. On the other hand, the presented first extension study can be used for all non-extendable basic units is one of the prominent values of the study. Simulation studies showing modulation methods, switching patterns, and signal outputs were performed with Matlab/Simulink. A prototype of the proposed main module has been realized and tested in the laboratory with an FPGA processing board. Experimental results have been verified with simulation results, and the performance of the proposed topology has been proven.

In this paper, a low power transconductor-capacitor (Gm-C) filter with programmable cutoff frequency is designed for electroencephalogram (EEG), electrocardiogram (ECG), and surface electromyography (sEMG) biosignals. The second order Butterworth low pass filter (LPF) is designed as an interface between an instrumentation amplifier (IA) and analog to digital converter (ADC). The proposed Gm-C filter suppresses out of band components and also plays anti-aliasing role. With the variable transconductance based on flipped voltage follower (FVF), the cutoff frequencies of 100 Hz, 560 Hz, and 1.5 kHz are obtained for EEG, ECG, and sEMG, respectively. This structure has highly accurate by using a robust and low power common mode feedback (CMFB). With 0.8 V supply voltage, the total power consumption of the filter is only 56 nW, 100 nW, and 221 nW for cutoff frequencies of 100 Hz, 560 Hz, and 1.5 kHz, respectively. The proposed Gm-C filter is simulated in TSMC 65 nm CMOS technology and occupies an area of 0.12 mm2. The figure of merit (FOM) of the proposed filter is equal to 1.9 pW/pole.

Nowadays, Z-source inverter has received several attentions compared to the other power converters owing to its simplicity and reliability. In this paper, a refine control methodology of capacitor voltage control is presented based on third-order small signal analysis. The proposed control is applied to the improved switched inductor Z-Source inverter (ISL ZSI). Proportional, integral and derivative controller (PID) is adopted due to its capability to operate with large operation levels , reliable operation, and cheaper in implementation. In addition, the function of this control can be achieved even with incomplete system data or parameters variations. ISL-ZSI has been presented because of its advantages such as the high gain of DC voltage, low voltage stress for both the Z-network and the inverter bridge switches and ensure good soft starting. in addition, the inrush current has been removed based on its configuration. The proposed control is validated by both experimental and simulation results under input voltage change, load change, and steady state operations using DSP F28335 and MATLAB SIMULINK Real-Time Workspace (RTW).

In this work a self-configuration system and the frequency characterization for a fully integrated CMOS photodetector sensor is presented. The sensor is composed of pixels with programmable switches that allow each pixel to connect with its neighbors; in this way, an arbitrary detection pattern can be synthesized on it. The design was aimed to be part of an optical encoder based on a non-diffractive light beam, therefore, the purpose of the self-configuration routine is to find the center of the incident non-diffractive beam and then configure the detection pattern around it. The corresponding algorithm is implemented on a Zynq-7000 SoC allowing to automate the alignment of the beam with the detection pattern, without using micrometric positioning procedures. The frequency response of the analog front-end of the entire chip (the pixels and the amplification system) is addressed via SPICE simulations and experimental data, and is consistent with the classical mathematical models, allowing us to propose future improvements to the design.

A novel capacitor voltage-reduced bidirectional (CVRB) PWM DC-DC buck-boost converter is presented in this study. Compared to the conventional bidirectional buck-boost converter, the proposed converter has a lower voltage rating filter capacitor. Accordingly, the given converter has a lower cost and 3.3% higher power density than the conventional buck-boost converter. Additionally, the proposed converter is more efficient due to the direct power transfer feature. Besides, the semiconductor switches have no extra voltage/current stress. The theoretical analysis of the converter is made, and its mathematical analysis is presented. The novel converter is experimentally operated in both the buck and boost modes. The experimental waveforms are shown for both operations. The proposed converter is operated in 100 W output power and 20 kHz switching frequency conditions.

The standard van Neumann computer excels at many things. However, it can be very inefficient in solving optimization problems with a large solution space. For that reason, a novel analog approach, the oscillator-based Ising machine, has been proposed as a better alternative for dealing with such problems. In this work, we review the concept of oscillator-based Ising machines. In particular, we address how optimization problems can be mapped onto such machines when the QUBO formulation is given. Furthermore, we provide an ideal circuit that can be used in combination with the wave digital concept for real-time simulated annealing. The functionality of this circuit is explained on the basis of a Lyapunov stability analysis. The latter also provides an answer for the question: when has the Ising machine solved a mapped problem? At the end, we provide emulation results demonstrating the correlation between functionality and stability of the discussed machine. These results show that mapping a problem onto an Ising machine effectively maps the solution of the problem onto an equilibrium of the phase space.