Micro motors in the robotic application have the advantage of lightweight, small size, more reliable and highly efficient. The objective of this study is to improve the speed characteristics of micro ...PMBLDC for surgical robot applications. In this paper, the micro PMBLDC for various configurations of inter pole is developed to obtain the desired torque and magnetic flux. The PID controller and fuzzy logic controller using ANFIS is proposed to regulate the speed response of the BLDC motor. The combination of PID and fuzzy logic in the closed-loop gives a steady-state error of 2.376%, and the use of a PID controller alone gives a steady-state error of 12.5%. With the proposed design of the controller for BLDC motor, the desired speed with lesser steady-state error obtained for surgical stapler application.
A fundamental task in the dynamic simulation of parabolic trough power plants (PTPP) is to understand the behavior of the system physics and control loops in the presence of weather variations. This ...study provides a detailed description of the advanced controllers used in the power block (PB) of a 50 MWel parabolic trough power plant (PTPP). The PB model is achieved using APROS software based on the actual specifications of the existing power plant. To verify the behaviour of the PB model, a comparison between the simulated results and given real data is documented depending on a previous study, and the results indicate a reasonable degree of correspondence. The purpose of this study is to create reference models for the PB. Thereby, developers and engineers will have a better understanding of the state of the art of advanced control loops in these power plants. Moreover, these types of models can be used to specify the most suitable mode of operation for the power plant. In addition, this study gives an overview of dynamic simulation for the design, optimisation and development of power blocks in parabolic trough power plants.
The publication presents some technical solutions of mechanical systems created on the basis of gears, the design of which includes additional elements with nonlinear properties. The characteristics ...of such elements with automatic control stiffness control allow to implement a universal design approach mechanical systems providing the property of adaptation to variable external loading of mechanical systems at the design stage, while improving the dynamic quality of the system.
This paper presents a real-time feedback control system for evanescent-mode cavity filters. The control loop monitors the frequency of each cavity in the filter and adjusts the bias voltage on the ...tuning piezoelectric actuator based on the monitoring data, such that each resonator of the filter is at the desired frequency. The control system can tune the filter regardless of any effects from hysteresis or creep. While applicable to a variety of filter structures, the presented control system has been validated on a second-order bandstop filter built using a standard PCB process. The control system can successfully tune the filter from 0.9 to 1.45 GHz (550-MHz tuning range or 61%) without affecting the RF performance. The control system is fully electronic with a digital interface for easier integration. It also exhibits a measured frequency resolution of 33-6 MHz (or 3.5%-0.4%).
A methodology for designing concurrent dual-band high efficiency power amplifiers (PAs) is presented in this letter. Load-pull simulations based on active device model are performed in two different ...bands to find the optimal required impedance conditions. A novel matching network with up to third order harmonic control is proposed to realize the high-efficiency mode matching in the two designed bands. A 1.9/2.6 GHz GaN PA is then designed to verify this method. The realized dual-band PA delivers above 10 W output power with more than 74% drain efficiency in the both operation bands.
This paper introduces a design for a charge pump DC-DC boost regulator with an integrated low-voltage control circuit. With a charge pump and feedback circuits implemented in 0.35 µm CMOS technology, ...the proposed DC-DC boost regulator offers an efficient device solution for low-power applications. The proposed design employs an error amplifier, oscillator, and comparator in the control circuit which is designed with a supply voltage of 1.8–3.5 V and 2 MHz frequency. Stability is obtained via a pole-zero compensation in the feedback circuit. The charge pump regulator with four pump stages and the whole regulator circuit are analyzed using the Cadence simulation tool. Measurements of the fabricated 0.35 µm CMOS regulator show that the transient time of the error amplifier is controlled within 1.0 µsec and the output voltage is accurately controlled from 7.8 V to 9.4 V with 27–38 mV ripple and 4.5 mA maximum current.
Semiconductor lasers are widely used in incoherent/coherent optical communications, optical fiber sensing, and lidar due to their small size, high efficiency, and immunity to vibrations. To support ...the continuous evolution of these high-performance application systems, the noise characteristics of semiconductor lasers play a key role and the noise levels need to be reduced to unprecedentedly low values (such as quantum limit). In this paper, a comprehensive overview on the principles, measurements, and suppressions of semiconductor laser noises are provided. First, we introduce the analysis models and key performance indicators of semiconductor lasers related to noise. Then, different noise measurement systems are investigated for semiconductor lasers and the noise characteristics are fully analyzed. Next, the noise suppression methods towards semiconductor lasers are demonstrated from three aspects: the chip structures, the external cavity optical feedback technology and the driving and controlling circuits. Finally, we summarize the recent advances on the noise measurement and suppression of semiconductor laser, future prospects are also discussed.
A Harmonic Control Circuit (HCC) is one of the most important blocks in the Class-F power amplifiers, which should pass the even harmonics and suppress the odd harmonics. Long open stubs are usually ...used to suppress odd harmonics in the conventional Class-F power amplifiers, which resulted in the large size of the amplifiers. In this work, two ClassF F are designed, a simple amplifier with traditional HCC and proposed PA with a proposed HCC. The proposed HCC suppresses third, fifth and seventh harmonics and easily pass second, fourth and sixth harmonics. In the proposed amplifier with proposed HCC, the design parameters are improved compared to the simple Class-F with traditional HCC. The power added efficiency (PAE), drain efficiency (DE) and gain parameters are increased from 76%, 79% and 19.4 dB to 79.2%, 82.2% and 21.2 dB, respectively. The proposed PA is fabricated, measured and results show that the proposed PA correctly works at 0.9 GHz with 0.12 GHz bandwidth.
Modular multilevel converter (MMC) is a proven technology for HVDC applications due to its salient features such as modularity and excellent power quality. To ensure best possible grid support, ...recent grid codes require incorporating fault ride-through (FRT) strategies so that HVDC converter stations remain connected and maintain reliable operation under various symmetrical and asymmetrical AC faults. In this paper, a communication-free enhanced fault ride-through technique without the need of DC chopper has been proposed. The proposed FRT strategy ensures quick post fault recovery operation and can effectively manage DC link and capacitor voltages within safe limits. Along with proposed FRT strategy, in order to avoid high circulating current (CC) inside an MMC, this paper has proposed an optimal circulating current control approach based on proportional resonant and PI controllers in an abc reference frame. The suggested technique lowers the ripple in capacitor voltages while reducing the magnitude of the CC. Under both balanced and unbalanced ac grid conditions, the ripple in the dc link voltage is also reduced without the use of dual synchronous reference frame or any additional controllers. Simulation results confirm the effectiveness of the proposed FRT and CC suppression techniques for a 580-kV, 850-MW MMC-based HVDC system.
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