Parallel Compensation Technique Research Articles

Modified Broadband Ruthroff-Type Transmission Line Transformer Balun for Isolation-Enhanced Passive Mixer Design.

Generalized broadband operation facilitates multifunction or multiband highly integrated applications, such as modern transceiver systems, where ultra-wideband bidirectional passive mixers are favored to avoid a complex up/down-conversion scheme. In this paper, a modified Ruthroff-type transmission line transformer (TLT) balun is presented to enhance the isolation of the mixer from the local oscillator (LO) to the radio frequency (RF). Compared to the conventional methods, the proposed Ruthroff-type architecture adopts a combination of shunt capacitors and parallel coupled lines to improve the return loss at the LO port, thus effectively avoiding the area consumption for the diode-to-balun impedance transformation while simultaneously providing a suitable point for IF extraction. In addition, a parallel compensation technique consisting of an inductor and resistor is applied to the RF balun to significantly improve the amplitude/phase balance performance over a wide bandwidth. Benefiting from the aforementioned operations, an isolation-enhanced 8-30 GHz passive double-balanced mixer is designed as a proof-of-principle demonstration via 0.15-micrometer GaAs p-HEMT technology. It exhibits ultra-broadband performance with 7 dB average conversion loss and 50 dB LO-to-RF isolation under 15 dBm LO power. The monolithic microwave integrated circuit area is 0.96 × 1.68 mm2 including all pads.

Simulation and synthesis of TS fuzzy system using parallel distribution compensation technique

Simulation and synthesis of TS fuzzy system using parallel distribution compensation technique

Load-Independent Duality of Current and Voltage Outputs of a Series- or Parallel-Compensated Inductive Power Transfer Converter With Optimized Efficiency

Inductive power transfer (IPT) systems are resonant converters whose output characteristics are mostly load dependent. Conditions for load-independent voltage-transfer ratios of IPT systems have been studied. However, load-independent current output can be more desirable for applications such as battery charging and LED driving. Theoretical operating frequencies for maximal efficiency of operation and load-independent voltage output of the IPT system have been explored in our previous paper. Using the duality concept, the system should exhibit similar characteristics as an IPT current output converter. Thus, in this paper, operating frequencies for maximal efficiency of operation and load-independent current output of the IPT system are explored, the aim being to identify some practical power-conversion efficient and load-independent operating frequencies. Analysis for the series- and parallel-compensation techniques is performed in order to facilitate the design of output current converter with an efficient power conversion and a load-independent frequency of operation. The analysis is supported with experimental results.

Dual-Miller Parallel Compensation for Low-Power Three-Stage Amplifier with a Wide Range of Capacitive Loads

In this paper, a dual-Miller parallel compensation (DMPC) technique for low-power three-stage amplifier is presented with detailed theoretical analysis. A feedback network realized by capacitor and transconductance is added between the first and third stage, which improves significantly the performance when driving large capacitive loads. Furthermore, it is found to be stable for a wide range of capacitive loads. The proposed DMPC amplifier has been implemented in a 0.13-μm CMOS process and the chip area is 0.17×0.11 mm2. It achieves a 0.87 MHz gain-bandwidth product by consuming a total current of 41 μA. The DMPC amplifier is verified to be stable when the load capacitor ranges from 8 pF to 2 nF.

Fuzzy control for geometrically nonlinear vibration of piezoelectric flexible plates

This paper presents a LMI(linear matrix inequality)-based fuzzy approach of modeling and active vibration control of geometrically nonlinear flexible plates with piezoelectric materials as actuators and sensors. The large-amplitude vibration characteristics and dynamic partial differential equation of a piezoelectric flexible rectangular thin plate structure are obtained by using generalized Fourier series and numerical integral. Takagi-Sugeno (T-S) fuzzy model is employed to approximate the nonlinear structural system, which combines the fuzzy inference rule with the local linear state space model. A robust fuzzy dynamic output feedback control law based on the T-S fuzzy model is designed by the parallel distributed compensation (PDC) technique, and stability analysis and disturbance rejection problems are guaranteed by LMI method. The simulation result shows that the fuzzy dynamic output feedback controller based on a two-rule T-S fuzzy model performs well, and the vibration of plate structure with geometrical nonlinearity is suppressed, which is less complex in computation and can be practically implemented.

Fuzzy control with passivity synthesis for continuous affine Takagi‐Sugeno fuzzy systems

PurposeThe purpose of this paper is to propose a stability analysis and control synthesis for achieving passivity properties of a class of continuous‐time nonlinear systems. These nonlinear systems are represented via continuous affine Takagi‐Sugeno (T‐S) fuzzy models, which played an important role in nonlinear control systems. The affine T‐S fuzzy models are more approximate than homogeneous T‐S fuzzy models for modeling nonlinear systems. Using the energy concept of passivity theory with Lyapunov function, the conditions are derived to ensure the passivity and stability of nonlinear systems. Based on the parallel distribution compensation (PDC) technique, this paper proposes a fuzzy controller design approach to achieve the passivity and stability for the continuous affine T‐S fuzzy systems.Design/methodology/approachFor solving stability and stabilization problems of affine T‐S fuzzy models, the conversion techniques and passive theory are employed to derive the stability conditions. By applying the linear matrix inequality technique, a modified iterative linear matrix inequality algorithm is proposed to determine and update the auxiliary variables for finding feasible solutions of these stability conditions.FindingsBy studying the numerical example, the proposed design technique of this paper is an effectiveness and useful approach to design the PDC‐based fuzzy controller. From the simulation results, the considered nonlinear system with external disturbances driven by proposed design fuzzy controller is stable and strictly input passive.Originality/valueThis paper is interesting for designing fuzzy controller to guarantee the stability and strict input passivity of affine T‐S fuzzy models.

H ∞ Fuzzy Filtering for Discrete-Time Nonlinear Systems via Fuzzy Lyapunov Function Approach

This paper is concerned with the H ? fuzzy filtering problem for a class of discrete-time fuzzy systems. The objective is to design a stable filter guaranteeing the asymptotic stability and a prescribed H ? performance of the filtering error system. Motivated by the parallel distributed compensation (PDC) technique, a new filter model is proposed in this paper. Both full-order and reduced-order filters are established, and they can be obtained from the solution of convex optimization problems in terms of linear matrix inequalities (LMIs). When these LMIs are feasible, an explicit expression of a desired H ? fuzzy filter is given. A numerical example is provided to demonstrate the effectiveness and applicability of the proposed design approach.

A dual-path bandwidth extension amplifier topology with dual-loop parallel compensation

A dual-path amplifier topology with dual-loop parallel compensation technique is proposed for low-power three-stage amplifiers. By using two parallel high-speed paths for high-frequency signal propagation, there is no passive capacitive feedback network loaded at the amplifier output. Both the bandwidth and slew rate are thus significantly improved. Implemented in a 0.6-μm CMOS process, the proposed three-stage amplifier has over 100-dB gain, 7-MHz gain-bandwidth product, and 3.3-V/μs average slew rate while only dissipating 330 μW at 1.5 V, when driving a 25-k/spl Omega///120-pF load. The proposed amplifier achieves at least two times improvement in bandwidth-to-power and slew-rate-to-power efficiencies than all other reported multistage amplifiers using different compensation topologies.

A Study on Control Design Method Using Parallel Compensation Technique

In the present paper, we study on a control design using parallel compensation technique. Parallel compensation technique is applied to many control design problem such as simple adaptive control, robust control using phase information and the parametrization of all proper stabilizing controllers for minimum phase strictly proper system. The parallel compensation technique is used so as to expand applicable plant of simple adaptive control and robust control using phase information. However the relationship between controllers that is obtained using parallel compensation technique and the parametrization of all stabilizing controllers have never considered. In the present paper, we consider this problem and give the necessary and sufficient condition that the class of controllers that is obtained using parallel compensation technique equal to that of controllers for the plant.

The Parametrization of All Stabilizing Repetitive Controllers for Cetain Class of Non-Minimum Phase Systems

In the present paper, we give explicit parametrization of all causal stabilizing repetitive controllers for single-input/single-output continuous time certain class of non-minimum phase systems. The parametrization of all causal stabilizing repetitive controllers was first studied by Hara and Yamamoto. Katoh and Funahashi give the parametrization for the class of all stabilizing repetitive controllers for minimum phase biproper plants by solving the Bezout equation explicitly. However, Katoh and Funahashi assumed the plant is asymptotically stable. Using parallel compensation technique, Yamada and Okuyama gave explicit parametrization of all repetitive controllers for minimum phase systems that is not necessarily stable. We expand the result by Yamada and Okuyama and give the parametrization of all causal stabilizing controllers for certain class of non-minimum phase systems. Finally, a numerical example is used to illustrate the effectiveness of the proposed method.

A Design Method for Robust Control Systems Using Phase Information for Minimum Phase Systems with Uncertain Relative Degree

In this paper, we examine a design method for robust control systems with robust stability for minimum phase systems using phase information. Yamada clarified that, using phase information, low sensitivity control systems with robust stability can be achieved if the relative degree of plant is equal to or 1-degree smaller than that of the nominal plant. In many cases, it is difficult to obtain the accurate relative degree of plant. The purpose of this paper is to expand the result by Yamada and give a design method for low sensitivity control system for the system with uncertain relative degree using phase information. In order to design low sensitivity control with robust stability, we adapt the idea of fusion of robust control design using phase information and the parallel compensation technique. A design procedure for low sensitivity control with robust stability is presented. Finally, without solving interpolation problem, a design method for low sensitivity robust servo control systems with robust stability is presented.

THE PARAMETERIZATION OF ALL STABILIZING REPETITIVE CONTROLLERS FOR A CERTAIN CLASS OF NON-MINIMUM PHASE SYSTEMS

We give an explicit parameterization of all causal stabilizing repetitive controllers for single-input/single-output continuous time non-minimum phase systems of a certain class. When the plant meets certain conditions, using the parallel compensation technique, we obtain the parameterization of all repetitive controllers. Finally, a numerical example shows the effectiveness of this parameterization.

A modification to the fast decoupled power flow for networks with high R/X ratios

The reliability of the fast decoupled load-flow method for most power systems is high, but it presents difficulties in convergence for systems with high ratios of branch resistance to reactance. Modifications that retain the advantages of this method but can handle high r/x ratios are of interest, and compensation techniques have been used for this purpose. Both the series and parallel compensation techniques, however, give mixed results. A modification is presented that performed better on several test systems. The test results show that this method not only converges well for systems with high r/x ratios but also is only slightly less efficient than the fast decoupled method for systems with normal ratios. >

Nominated Lecture: The Mechanics of Instrumentation

In this lecture instrumentation will be interpreted as the ways and means to transport and modify signals so as to make them suitable for the input channels of human beings and automatic controllers. A difference may be made between measuring and control systems; the first present the value of the measured quantity in an appropriate way, the second also formulate and execute command signals. Modern control theory and techniques have an increasing influence on the arts of instrumentation. An important part of all instrumentation systems is the transducers, which convert the value of the signal to be measured to another physical dimension, more suited for transport or evaluation. Typical are the conversions to electric voltages, pneumatic or hydraulic pressures. The main requirements for the design of a transducer are a low energy consumption from the measuring source, fast response and low susceptibility to disturbing signals and noise. At the input there exist besides the value of the signal to be measured xm an associate signal ym, such that xmym has the dimension of energy W (watt). The generalized impedance Z is defined as Z = xm/ym, so that W = xm2/ Z. In general W should be small, requiring Z being large, sometimes approaching infinity. On the other hand, examples will be given where Z must have a certain specified value. A low value of W can be obtained either by using a very sensitive primary sensor and applying sufficient signal amplification afterwards or by using feedback techniques. Most of the primary sensors transfer the measured quantity into a displacement or elongation of the measuring element. A fast response requires small moving parts and a high stiffness. This lowers the sensitivity and efficiency of the signal conversion. Feedback techniques make it possible to increase the high-frequency response without undue miniaturization of the mechanical parts. The shape and the way of loading of the measuring elements have great influence on the efficiency of signal conversion and a figure of merit will be defined and applied to a number of common elements. An instrumentation system should be insensitive to disturbing signals and noise. This requires no, or a non-changing, interaction between adjacent components. Further the design should be such that such disturbances as temperature and barometric changes, accelerations, vibrations and gravity have no influence on the output. The first step is to make the design as insensitive as possible for these errors and thereafter by means of series—or parallel-compensation techniques—the remaining effects can be reduced to the required values.