Frequency tracking fundamentals, challenges, and solutions

2011 ◽  
Author(s):  
D. Costello ◽  
K. Zimmerman
Keyword(s):  
Frequency Tracking

scholarly journals Optimal Design of LLC Resonant DC Transformer under Adaptive Frequency Tracking Strategy

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2160
Author(s):  
Yu Tang ◽  
Dekai Kong ◽  
Chenxu Duan ◽  
Hao Sun
Keyword(s):  
Working Condition ◽  
Transmission Efficiency ◽  
Switching Frequency ◽  
Optimal Operating ◽  
Frequency Tracking ◽  
Zero Current ◽  
Llc Resonant Converter ◽  
Dc Transformer ◽  
Zero Voltage ◽  
Tracking Strategy

In recent years, the LLC (inductor–inductor–capacitor) DC transformer has been widely used in communication and computer power supply because of its advantages of zero voltage conduction of primary switch and zero current turn off concerning the output rectifier diode. To obtain higher transmission efficiency and make the LLC DC transformer always run at the optimal operating point, the switching frequency of the LLC DC transformer should work at the resonance frequency of the circuit. In actual conditions, the optimal operating frequency of the LLC DC transformer will be changed due to the influences of the working condition on the circuit parameters and the load change. Therefore, the LLC DC transformer controlled by the fixed frequency mode will not be in the best working condition. In this paper, an adaptive frequency tracking method is used to control the circuit; when the circuit parameters change, the LLC DC transformer can always be in the best working state. Then, the influence of circuit parameters such as output power and excitation inductor on the optimal working point of the LLC DC transformer is analyzed in detail. Finally, a 1 kW LLC resonant converter prototype is designed under laboratory conditions to verify the feasibility of the control strategy.

Study of Induction Heating Power Supply Based on 74HC4046

2014 ◽  
Vol 1008-1009 ◽  
pp. 663-667 ◽  
Author(s):  
Yan Cui ◽  
Xiao Jun He ◽  
Ze Ping Lin ◽  
Qing Bin Chen ◽  
Wei Hao Yang ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Induction Heating ◽  
Power Supply ◽  
Simulation Experiment ◽  
Tracking System ◽  
Output Frequency ◽  
Phase Compensation ◽  
Frequency Tracking ◽  
Iron Load ◽  
Inverter Power Supply

According to the change of resistivity and magnetic permeability of iron load which will influence the resonance frequency in the process of induction heating, this paper presents a frequency tracking system based on the 74HC4046. It can control the output frequency of the power supply in real time, and make the power output frequency to trace the resonance frequency of load. This paper also analyses the phase compensation of the control system, and proposes a new way of phase compensation. The corresponding simulation experiment is done finally. It provides the theory basis to analyze and design an inverter power supply.

Implementation and Performance Assessment of a Vector Tracking Method Based on a Software GPS Receiver

2011 ◽  
Vol 64 (S1) ◽  
pp. S151-S161 ◽  
Author(s):  
Sihao Zhao ◽  
Mingquan Lu ◽  
Zhenming Feng
Keyword(s):  
Global Positioning System ◽  
Carrier Frequency ◽  
Gps Receiver ◽  
Tracking Loop ◽  
Frequency Tracking ◽  
Tracking Method ◽  
Global Positioning ◽  
Vector Tracking ◽  
Tracking Loops ◽  
And Performance

A number of methods have been developed to enhance the robustness of Global Positioning System (GPS) receivers when there are a limited number of visible satellites. Vector tracking is one of them. It utilizes information from all channels to aid the processing of individual channels to generate receiver positions and velocities. This paper analyzes relationships among code phase, carrier frequency, and receiver position and velocity, and presents a vector loop-tracking algorithm using an Extended Kalman filter implemented in a Matlab-based GPS software receiver. Simulated GPS signals are generated to test the proposed vector tracking method. The results show that when some of the satellites are blocked, the vector tracking loop provides better carrier frequency tracking results for the blocked signals and produces more accurate navigation solutions compared with traditional scalar tracking loops.

Automatic Frequency-Tracking Control for Ultrasound Welding System

2011 ◽  
Vol 204-210 ◽  
pp. 2041-2044
Author(s):  
Kao Feng Yarn ◽  
King Kung Wu ◽  
Kai Hsing Ma ◽  
Wen Chung Chang
Keyword(s):  
High Power ◽  
Tracking Control ◽  
Control Method ◽  
Ultrasonic Welding ◽  
Automatic Frequency ◽  
Frequency Tracking ◽  
Power Ultrasonic ◽  
Fpga Chip ◽  
Working Frequency ◽  
Welding System

A new frequency-tracking control method to catch the optimal working frequency for the high power ultrasonic welding system is proposed. In a high power ultrasonic resonant system, the induced high temperature will change the working frequency. Therefore, the proposed control method to track the optimal working frequency becomes very attractive and important. This control method is practically implemented by a FPGA chip which basically includes two logic circuits. One logic circuit is to find the optimal working frequency automatically and the other one is to adjust the working frequency by detecting the working current simultaneously. Experimental results exhibit the new method can effectively control and track frequency for high power ultrasonic welding system.

scholarly journals On frequency tracking in harmonic acoustic signals

2017 ◽  
Author(s):  
Martin Lindfors ◽  
Gustaf Hendeby ◽  
Fredrik Gustafsson ◽  
Rickard Karlsson
Keyword(s):  
Acoustic Signals ◽  
Frequency Tracking

Analysis of a Natural Frequency Tracking System for MEMS Fatigue Testing

2001 ◽  
Author(s):  
Xiaotian Sun ◽  
Roberto Horowitz ◽  
Kyriakos Komvopoulos
Keyword(s):  
Control System ◽  
Natural Frequency ◽  
Averaging Method ◽  
Fatigue Testing ◽  
Tracking System ◽  
Frequency Tracking ◽  
At Resonance ◽  
Mems Resonator ◽  
Control Gain ◽  
Good Agreement

Abstract A nonlinear control system that can track the natural frequency of a MEMS resonator was developed in this study. Due to the evolution of fatigue damage, the natural frequency of the resonator decreases. To maintain the device at resonance, a phase-locked loop system is used to track the frequency decay and adjust the driving force accordingly. A model for the control system is introduced and the system behavior is analyzed using an averaging method. A quantitative criterion for selecting the control gain to achieve stability is derived from the analysis. Simulation results are shown to be in good agreement with the prediction of the theoretical analysis.

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