Variable Phase Control Research Articles

Synthesis of phased array antenna for side lobe level reduction using the differential evolution algorithm

In this paper, we synthesis an array consisting of uniformly excited unequally spaced elements for reducing SLLs. A globally optimal solution for the array elements phase and position is determined by using a differential evolutionary algorithm for a given radiation pattern. Reduced side-lobe levels are observed with position-phase synthesis. The obtained results are compared with the possible two cases i.e., uniform amplitude equal phase (variable position-control) and uniform amplitude unequal phase (variable phase-control). The obtained results justify that the position-phase synthesis technique is not only reduces the side-lobe levels to (− 25.28) dB, but also preserves the advantages of both variable position-controlled synthesis and variable phase-controlled synthesis with a minimum number of array elements.

Analysis of dynamic wireless charging using tunable self-oscillating method

ABSTRACTIn this paper, Tunable Self-Oscillating Switching (TSOS) technique for Dynamic Wireless Charging (DWC) of Electric Vehicle (EV) is investigated. TSOS is a suitable option for DWC, which has parameter variation and requires fast frequency tracking. The system consists of a high-frequency full-bridge inverter, a series–series compensated loosely coupled transformer that is created by Unequal Double D (UDD) coils and a Li-Ion battery as the load that is connected to the output of the full-bridge rectifier. To achieve high efficiency and energy transfer and realise zero voltage switching, the phase of total impedance in steady state condition is investigated. To limit the overshoot of current in the system, a variable phase control method is proposed. Also, an investigation on the proper point to start the charger is performed to decrease the overshoot of current and increase the efficiency. Using this method, overshoot of current could be limited to 50% and energy efficiency could be at least 92.68%. To analyse this method, simulation is done in the Simulink/MATLAB, and to verify the results, a laboratory prototype is implemented.Abbreviations:TSOS: Tunable Self-Oscillating Switching; DWC: Dynamic Wireless Charging; EV: Electric Vehicle; DD: Double D; UDD: Unequal Double D; IPT: Inductive Power Transfer; CT: Current Transformer; MCU: Micro Controller Unit; SOS: Self-Oscillating Switching; ZVZCS: Zero Voltage and Zero Current Switching; EMI: Electromagnetic Interference; SS: Series–Series; PLL: Phase-Locked Loop; DC: Direct Current

Multistage multiphase switched‐capacitor DC–DC converter with variable‐phase and PWM control

SUMMARYA closed‐loop multistage multiphase switched‐capacitor converter (n‐stagep‐phase MPSC) is proposed with a variable‐phase control (VPC) and a pulse‐width‐modulation (PWM) technique for low‐power step‐up conversion and high‐efficiency regulation. In thisn‐stage MPSC,nvoltage doublers are connected in series for boosting the voltage gain up to 2nat most. Here, VPC is suggested to realize a variable multiphase operation by changing the phase numberpand topological path for the more suitable level of voltage gain so as to improve the power efficiency, especially for the lower output voltage Besides, PWM is adopted not only to enhance output regulation for different desired outputs, but also to reinforce output robustness to source/loading variation. Further, some theoretical analyses and designs include:n‐stagep‐phase MPSC model, steady‐state analysis, conversion ratio, power efficiency, output ripple, stability, capacitance selection, and control design. Finally, the closed‐loop MPSC is simulated, and the hardware is implemented and tested. All the results are illustrated to show the efficacy of the proposed scheme. Copyright © 2011 John Wiley & Sons, Ltd.

Design and Analysis of Multistage Multiphase Switched-Capacitor Boost DC–AC Inverter

A closed-loop multistage ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$n$</tex> </formula> -stage) multiphase ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$p$</tex> </formula> -phase) switched-capacitor boost dc–ac inverter (MPSCI) is proposed by combining a variable-phase control (VPC) and sinusoidal pulsewidth-modulation (SPWM) technique for low-power step-up inversion/regulation. Its power stage contains two parts: an MPSC booster (front) and an H-bridge (rear). An <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$n$</tex></formula> -stage <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$p$</tex></formula> -phase MPSC is for an inductor-less boost dc–dc conversion, where <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$n$</tex></formula> voltage doublers are in series for boosting voltage gain up to <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$2^{n}$</tex> </formula> at most. For improving efficiency, VPC is suggested to realize a variable multiphase operation by changing phase number <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$p$</tex></formula> and topological path for more suitable gain level. An H-bridge is employed for dc–ac conversion, where four switches are controlled by SPWM not only for full-wave operation, but also for enhancing output regulation as well as robustness to source/loading variation. The analysis and design include an MPSCI model, steady-state/dynamic analysis, conversion ratio, power efficiency, stability, capacitance selection, total harmonic distortion (THD), filter, and control design. Finally, the closed-loop MPSCI is simulated, and the hardware is implemented and tested. All results are illustrated to show the efficacy of the proposed scheme.

HIGH-EFFICIENCY 2-STAGE MULTIPHASE SWITCHED-CAPACITOR CONVERTER VIA VARIABLE-PHASE AND PWM CONTROL

A closed-loop scheme of 2-stage multiphase switched-capacitor (MPSC) converter is proposed by combining variable-phase control (VPC) and pulse-width-modulation (PWM) technique for low-power DC-DC step-up conversion and high-efficiency output regulation. In this MPSC, there are 2 voltage doublers in series for boosting voltage gain up to 4 at most. Here, VPC is suggested to improve power efficiency, especially for the lower output voltage. It realizes a variable multiphase operation by changing MPSC topological path for more suitable level of voltage gain (4x/3x/2x/1x) according to the desired output. Besides, PWM is adopted for better output regulation not only to compensate dynamic error, but also to reinforce robustness against source/loading variation. Further, the theoretical analysis and design include: MPSC model, steady-state analysis, power efficiency, conversion ratio, ripple percentage, capacitance selection, stability, and control design. Finally, the closed-loop MPSC is simulated, and the hardware implementation is realized and tested. All the results are illustrated to show the efficacy of the proposed scheme.

Variable phase control of wing rock

This paper addresses a variable phase control issue for suppressing wing rock with hysteresis. In free-to-roll tests, as the angle of attack (AOA) is increased, the roll angle versus the rolling moment indicates hysteresis and provides clues about where wing rock motion is being driven and where the motion is being damped. We present the analysis method of wing rock energy to explain the mechanism of wing rock and the formation of hysteresis, and then develop a variable phase control (VPC) scheme to compensate the phase and magnitude distortions. The effectiveness and robustness of the proposed scheme are demonstrated by suppressing wing rock phenomenon at various AOA and any initial conditions.

Erratum: “Rapidly variable phase control method of capacitor currents,” volume 188, number 3, 1997, pages 67–77

It has been brought to the attention of the publisher that an error appeared in the title of the above article. The title as it appears here is correct. We apologize for any inconvenience this error may have caused the author.

Rapidly variable phase control method of character currents

Rapidly variable phase control method of character currents

Rapidly variable phase control method of character currents

Phase control of capacitor currents is obtained by the method of forced turn-off of the switching devices and turn-on at the phases when the potential differences between ac source voltage and residual voltage of capacitor become zero. For the technique of forced turn-off of the switching devices which conduct the capacitor currents, two circuit methods have been reported. One method used back-to-back thyristor choppers, and the other used a coupling reactor. However, the former generates pulse noises and the latter operates unstably. Therefore, a simple and stable circuit method, without generations of pulse noises, is expected for practical uses. For this purpose, new circuit methods are designed using self-turn-off devices. This paper reports the new method and characteristics of phase controls of capacitor currents when self-turn-off devices are used as the switching devices. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (3): 67–77, 1997

Rapidly Variable Phase Control Method of Capacitor Currents.

Phase control of capacitor currents is obtained by the method of forced turn-off of the switching devices and turn-on at the phases when the potential differences between AC source voltage and residual voltage of capacitor become zero.For the technique of forced turn-off of the switching devices which conduct the capacitor currents, two circuit methods have been reported. One of the method used back-to-back thyristor choppers, and the another used coupling reactor. But the former generates pulse noises and the latter operates unstably. Therefore, simple and stable circuit method, without generations of pulse noises, are expected for practical uses. For this purpose, new circuit methods are designed using self-turn-off devices.This paper reports about the new method and characteristics of phase controls of capacitor currents when self-turn-off devices are used as the switching devices.

The Electronic Isograph for Roots of Polynomials

An electronic apparatus which assists in the finding of the roots of polynomials is described. The device accepts the coefficients of polynomials of degree 10 or less and yields the absolute magnitude of the roots to a precision of 0.01 relative to the largest coefficient in the polynomial and an angular accuracy of 0.3 degree on the angle of the root. The method used is the electronic analog of the expression ω= ∑ anzn= ∑ anrn cosnθ+j ∑ anrn sinnθ.Sinnθ and cosnθ are generated by a motor-driven commutator. The radius r is controlled manually. Hence a plot of ω is placed on the oscilloscope for a fixed r as a function of θ. To find the root r is manipulated until ω crosses the origin in the ω-plane. The value of θ is found by inserting a pip on the intensity of the oscilloscope under a variable phase control. When this pip is moved to the origin of the ω-plane the phase meter indicates the angle of the root in the z plane.