Search

This paper addresses the tracking control problem for a class of uncertain nonlinear systems with full state deferred constraints. The constraints considered occur after a period of system operation rather than from the beginning. An attempt has been made to use a shifting function to realize the purpose of deferred constraint. Moreover, the difficulty of asymmetric constraint on states comes from the design on barrier function. Due to this, an unified barrier function is proposed to prevent system states from violating the constraint range, indirectly. Meanwhile, it effectively removes the restriction condition used in existing results that the upper and lower bound signs of constraint functions are the same. Consequently, the goals of tracking a reference signal and state constraints are achieved through the control scheme designed. Theoretical analysis and simulations are presented to demonstrate the efficacy of the proposed control strategy.

This article presents and analyzes a wide-locking range divide-by-5 injection-locked frequency divider (ILFD) manufactured in the TSMC 0.18- $\mu \text{m}$ processes. The ILFD uses the balanced injection method and uses the pure harmonic mixing approach at low injection power, and it is designed with an RLC dual-resonance resonator. The harmonic mixer relies on the self-generated second harmonic, which increases with injection power. Because of no narrowband filter as used in the linear mixer counterpart, the divide-by-5 ILFD uses a wideband design method. In addition, the ILFD enhances the divide-by-5 locking range via the overlapped dual-band locking ranges as verified by both experiment and simulation. At the drain–source bias ${V} _{\text{DD}}$ of 0.8 V and at the incident power of 0 dBm, the locking range of the divide-by-5 ILFD is 3.6 GHz, from the incident frequency 13.0–16.6 GHz with the percentage 24.3%. The core power consumption is 4.09 mW, and the die area is $1.02\times0.93$ mm2. [ABSTRACT FROM AUTHOR]

This article designs and analyzes wide locking range (LR) high even-modulus LC-tank injection-locked frequency dividers (ILFDs) with current-reused topologies. The current-reused LC ILFD uses two stacked LC sub-ILFDs sharing the same dc current. The current-reused ILFD becomes a divide-by-4 ($\div 4$) ILFD, when both sub-ILFDs are used $\div 2$ ILFDs, and it is used as a divide-by-8 ($\div 8$) ILFD when one sub-ILFD is used a $\div 4$ ILFD. Both sub-ILFDs use nMOSFETs as linear injection mixers for high conversion gain. For the $\div 8$ LC ILFD designed in the TSMC 0.18- $\mu \text{m}$ CMOS process, the circuit uses one high-frequency $\div 4$ sub-ILFD and one low-frequency $\div 2$ sub-ILFD, at the supply of 1.6 V, and at the incident power of 0 dBm, the LR is 4 GHz (38.835%), from the incident frequency 8.3 to 12.3 GHz. The $\div 8$ ILFD core power consumption is 13.98 mW, and the die size is $1.2 \times 1.2$ mm2. Both the $\div 8$ LC ILFD and the $\div 4$ sub-ILFD have nonoverlapped and overlapped LRs, which are due to a dual-resonance resonator used in the varactor-free n-core sub-ILFD. The LC dual-resonance resonator is due to parasitic capacitors in active FETs and on-chip spiral inductors and inductive elements, and it is used to get wide overlapped LR. Two $\div 4$ LC ILFDs inherent in the designed circuit are also studied. [ABSTRACT FROM AUTHOR]

Voltage sags are often manifested as the permanent or incipient faults occurred in the power system because of equipment malfunctions or failures. The incipient faults that are originally self-cleaning faults may repeatedly occur and gradually develop to a permanent fault after its first occurrence. The incipient fault detection is considered as a crucial task in predictive maintenance for power equipment, such as transformers, circuit breakers, and underground cables. This paper proposes a hybrid method for incipient faults detection and classification. The proposed method firstladopts two extraction methods and two feature measures to obtain seven peculiar features from voltage waveforms of abnormal phases recorded by power quality monitors at substations in a transmission network. Then, a feature selection method and the support vector machine combined with particle swarm optimization are applied to classify various types of incipient faults. Test results show that the proposed method contributes relatively accurate classification of incipient faults and can be employed as a useful tool for condition monitoring of major power equipment in the transmission network. [ABSTRACT FROM AUTHOR]

Three-phase bridge converter is popular in ac–dc power conversion. The conventional sensor control with inner current loop and outer voltage loop is often used to control the three-phase bridge converter. Many three-phase sensorless control methods had been proposed to control the bridge converter with considering the inductance and inductor resistance. In this paper, the voltage drop of the power semiconductor is first considered in the proposed three-phase current sensorless control method. At first, the dynamic behaviors of three-phase bridge converter for power factor correction (PFC) applications are studied, and its equivalent three-switch model is developed. Based on this developed model, three-phase current sensorless control with only voltage controller is proposed. Additionally, the voltage-loop transfer function of PFC bridge converter controlled by the proposed method is modeled, and the result is helpful to obtain the controller parameter. The proposed control method is implemented on the DSP-based platform for evaluation. Finally, the provided simulation and experimental results demonstrate the performance of the proposed method. [ABSTRACT FROM AUTHOR]

In a near-field scanning system, each element of the measurement chain contributes to the thermal noise power density: probe, cables, amplifiers, and the measuring instrument. The signal-to-noise ratio (SNR) is strongly affected by the source output impedance, source temperature, the lossy transmission lines between probe and amplifiers, amplifier noise, amplifier temperature, and amplifier gain. By minimizing the loss between the probe and by using ultralow-noise amplifiers (noise figure (NF)<0.5 dB), SNR improves by >10 dB, compared to a setup using a 1-m cable and a 3-dB NF amplifier. Aresonant probe that is cooled with liquid nitrogen improves measurement SNR by an additional 10-12 dB, as compared to a broadband probe of similar loop size. To combine the advantages of a resonant probe, without sacrificing the ability to measure broadband, a proof of concept is demonstrated that uses a tunable resonant probe which is synchronized to the frequency sweep of the spectrum analyzer. [ABSTRACT FROM AUTHOR]

To improve the efficiency of the conventional boost-type power factor correction (PFC) converters with the diode bridge circuit, the PFC converters of bridgeless category are often used. Due to no series-connected switches and no short-through risks, the dual-boost half-bridge (DBHB) circuit is used as the PFC converter in this paper. In order to simplify the conventional two-loop control scheme and reduce the number of sensors, the behaviors of the DBHB PFC converter are studied and its equivalent single-switch model is developed. Then, the current sensorless control for the DBHB PFC converter is proposed to achieve voltage regulation and yield sinusoidal input current in phase with the input voltage without sensing any current. In addition, the proposed method is able to balance capacitor voltages naturally without adding any voltage balancing control loop. An 800-W DBHB PFC prototype is implemented to evaluate the control performance. Both simulation and experimental results are provided to demonstrate the proposed current sensorless control method. [ABSTRACT FROM AUTHOR]

This brief presents a low-power high-stability scan driver integrated by In–Zn–O (IZO) TFTs on polyimide substrate. Observed from the experimental results of the scan driver with 48 stages, there is no distortion and good noise-suppressed characteristics for the output waveforms. In one stage of the proposed scan driver, there only needs a small TFT connected to clock signals by using a feedback inverter and a dc output module to minimize the dynamic power consumption. It is measured that the power consumption for one stage of the proposed gate driver is 18.3 \mu \textW at the output swing of 15.3 V and the clock frequency of 50 kHz. There is a good noise-suppressed characteristic and high stability for the proposed scan driver as shown from a 300-h test. [ABSTRACT FROM AUTHOR]