Small-Signal Analysis of All-Si Microring Resonator Photodiode

All-silicon microring resonator photodiodes are attractive for silicon photonics integrated circuits due to their compactness, wavelength division multiplexing ability, and the absence of germanium growth. To analyze and evaluate the performance of the microring photodiode, we derived closed-form expression of the response transfer function with both electrical and optical behavior included, using a small-signal analysis. The thermo-optic nonlinearity resulting from optical loss and ohmic heating was simulated and considered in the model. The predicted response achieved close agreement with the experiment results, which provides an intuitive understanding of device performance. We analytically investigated the responsivity–bandwidth product and demonstrated that the performance is superior when the detuning frequency is zero.

Small-signal analysis of a single-stage bridgeless boost half-bridge AC/DC converter with bidirectional switch

A small-signal analysis of a single-stage bridgeless boost half-bridge alternating current/direct current (AC/DC) Converter with bidirectional switches is performed using circuit averaging method. The comprehensive approach to develop the small signal model from the steady state analysis is discussed. The small-signal model is then simulated with MATLAB Simulink. The small-signal model is verified through the comparison of the bode-plot obtained from MATLAB Simulink and the simulated large signal model in piecewise linear electrical circuit simulation (PLECS). The mathematical model obtain from the small-signal analysis is then used to determine the proportional gain K_p and integral gain K_i. In addition, the switch large-signal model is developed by considering the current and voltage waveforms during load transients and steady-state conditions.

Design and Implementation of a High Step-Up DC-DC Converter Based on the Conventional Boost and Buck-Boost Converters with High Value of the Efficiency Suitable for Renewable Application

This paper introduces a novel topology of the proposed converter that has these merits: (i) the topology of the converter is based on conventional boost and buck-boost converters, which has caused its simplicity; (ii) the voltage gain of the converter has provided higher values by the lower value of the duty cycle; (iii) due to the use of high-efficiency conventional topologies in its structure, the efficiency of the converter keeps its high value for a great interval of duty cycle; (iv) besides the increase of the voltage gain, the current/voltage stresses of the semiconductors have been kept low; (v) the continuous input current of this converter reduces the current stress of the capacitor in the input filter. It is worth noting that the proposed converter has been discussed in both ideal and non-ideal modes. Moreover, the operation of the converter has been discussed in both continuous/discontinuous current modes. The advantages of the converter have been compared with recently suggested converters. In addition, the different features of the converter have been discussed for different conditions. In the small-signal analysis, the appropriate compensator has been designed. Finally, the simulation and experimental results have been reported for 90 W output power, 90 V output voltage, 3-times voltage gain, and 100 kHz switching frequency.

Small-signal analysis and control implementation of boost converter fed PMDC motor for electric vehicle applications

Small-signal analysis of boost converter fed permanent magnet DC (PMDC) motor for electric vehicle applications is performed, and hardware implementation is realized in this paper. Extensive analysis is performed to identify the relevant steady-state and dynamic features of the proposed system with small-signal linearization, and relevant transfer functions are formulated. The nonlinear equations of the system are derived and then linearized around a stable operating point to construct a small-signal model. Transfer functions relating the control of the converter to the motor speed and control to input current are derived symbolically using computerized symbolic algebra in MathCAD. The control-to-output transfer functions are obtained by introducing perturbation in state variables, equating AC and DC quantities and proceeding with AC quantities. The principle of operation, operation modes, small-signal analysis, experimental verification, and the effectiveness of the speed control are discussed and presented. An experimental prototype is implemented using dSPACE DS1103-based digital signal processor, and the proposed model is used for online parameter tuning of the speed controller. The speed control dynamics and transient response are investigated under sudden load changes. The overall system performance is evaluated and verified experimentally based on a speed feedback control scheme for validation purposes.

Small-Signal Stability Analysis for Multi-Terminal LVDC Distribution Network Based on Distributed Secondary Control Strategy

This paper presents a detailed and accurate small-signal analysis model for a four-terminal low-voltage direct current (LVDC) distribution network with distributed secondary control strategy. To tackle the contradiction between power sharing accuracy and average voltage recovery ability of voltage source converters (VSCs), a distributed secondary control strategy is adopted, which is based on average consensus algorithm and local voting protocol. Furthermore, to analyze the stability of LVDC distribution network based on the proposed distributed secondary control strategy, a detailed and accurate small-signal analysis model is formulated which is derived from various non-linear state-space sub-models. The time-domain simulation and electromagnetic simulation are carried out to verify the validity and accuracy of the proposed model. Based on this model, the influence rules of main eigenvalues are summarized with the variation of PI control and DC line parameters. Time-domain simulations conducted in PSCAD are used to validate the operational limits of the secondary controllers and DC line obtained from the small-signal stability analysis.

A S-Type Bistable Locally-Active Memristor and Its Application in Oscillator Circuit

In this paper, a S-type memristor with tangent nonlinearity is proposed. The introduced memristor can generate two kinds of stable pinched hysteresis loops with initial conditions from two flanks of the initial critical point. The power-off plot verifies that the memristor is nonvolatile, and the DC V-I plot shows that the memristor is locally active with the locally-active region symmetrical about the origin. The equivalent circuit of the memristor, derived by small-signal analysis method, is used to study the dynamics near the operating point in the locally-active region. Owing to the bistable and locally-active properties and S-type DC V-I curve, this memristor is called S-type BLAM for short. Then, a new Wien-bridge oscillator circuit is designed by substituting one of its resistances with S-type BLAM. It find that the circuit system can produce chaotic oscillation and complex dynamic behavior, which is further confirmed by analog circuit experiment.