Quadrature Signal Generation Research Articles

An Adaptive Frequency-Fixed Second-Order Generalized Integrator-Quadrature Signal Generator Using Fractional-Order Conformal Mapping Based Approach

The frequency-fixed second-order generalized integrator-based quadrature signal generator (FFSOGI-QSG) has been widely used in grid synchronization applications. The major limitations of using this technique are the unequal amplitudes of in-phase and quadrature-phase signals under grid frequency variation, which causes double-frequency oscillatory and offset errors in FFSOGI-based phase-locked loop output. To overcome the issues, in this letter, a modified complex analysis of FFSOGI-QSG using fractional-order-based conformal mapping approach has been presented, and an adaptive FFSOGI-QSG (AFFSOGI-QSG) is proposed. The proposed AFFSOGI-QSG can adapt itself to the grid frequency variations through the adjustment of single tuning parameter, i.e., fractional-order gain. The proposed structure is also found to inherit the simplicity of the FFSOGI-QSG without changing the order of the system while demonstrating an improved disturbance rejection capability under various grid disturbances. Performance of the proposed AFFSOGI-QSG is finally validated against some well-known SOGI-QSGs using numerical results obtained from the MATLAB and experimental results from the dSPACE DS1104 hardware.

Cooperative Regulation of Imbalances in Three-Phase Four-Wire Microgrids Using Single-Phase Droop Control and Secondary Control Algorithms

Collaborative control of power converters operating in microgrids with unbalanced single-phase loads is difficult to achieve, considering that the voltages and currents have positive-, negative-, and zero-sequence components. In this paper, a new control scheme for collaborative control of four-leg microgrids is proposed. The main advantage of the proposed methodology is simplicity, because the sharing of the powers produced by the positive-, negative-, and zero-sequence voltage and currents is simple to achieve using the easy to implement and well-known droop control algorithms, i.e., as those based on $P$ – $\omega$ and $Q$ – $v$ droop control. The proposed droop algorithms do not require high bandwidth communication channels and the application of virtual impedances, whose design usually demands extensive simulation work, is not required. Three secondary control systems are also analyzed, discussed, and implemented in this paper to regulate the frequency, voltage, and phase at the point of common coupling (PCC), to achieve a balanced 50-Hz three-phase voltage supply in the PCC during steady-state operation. For these secondary control systems, single-phase phase-locked loop based on quadrature signal generators are implemented. Small signal modeling and design are discussed in this paper. A microgrid prototype of $\approx$ 5 kW, implemented using two power converters of 3 kW (each), is used to experimentally validate the proposed algorithms.

A W-Band 6-Bit Phase Shifter With 7 dB Gain and 1.35° RMS Phase Error in 130 nm SiGe BiCMOS

This brief presents a W-band 6-bit active phase shifter fabricated in $0.13~\mu \text{m}$ SiGe BiCMOS process. A wideband quadrature signal generator composed of a 90-degree hybrid and a pair of transformers is exploited for low insertion loss and superior balance. Conventional architecture used in gain control unit is replaced by a novel phase inverter-embedded variable gain amplifier to achieve a high gain and low complexity. In addition, a balun-first combiner with symmetrical layout is utilized at the output to keep as low the imbalance of I/Q paths as possible. The proposed phase shifter exhibits a record average gain of 7 dB at 79 GHz with a 3-dB bandwidth from 71.5 to 84.5 GHz. The variation of gain remains below 2.1 dB over 64 phase states. The measured RMS phase error is 1.35° at 78 GHz and remains below 3.5° from 72 to 82 GHz. The RMS gain error is measured to be 0.46 dB at 75 GHz and keeps less than 0.76 dB from 71 to 82 GHz. The measured input 1dB compression point amounts to −10 dBm. To the best of the author’s knowledge, this brief presents the lowest RMS phase error (1.35°) and the highest gain (7 dB) compared with the reported silicon-based W-band active phase shifters.

Analysis and Design of Wideband I/Q CMOS 100–200 Gb/s Modulators

This paper presents the analysis and design of wideband I/Q CMOS modulators and transmitters. Non-idealities and performance limitations of Cartesian transmitter and modulator systems are discussed, and circuit design techniques and analyses are shown. A DC-60 GHz I/Q modulator/transmitter chip in 45-nm SOI CMOS is presented as a critical building block for next-generation multi-standard and high-capacity wireless backhaul links. The modulator consists of a wideband quadrature signal generator, wideband buffers, and two current-combined DC-100 GHz low-noise double-balanced mixers driven in quadrature. The 1.4 mm2 modulator chip achieves 60 dB of dynamic range in a 1-GHz bandwidth, with an OP1dB of ~ −10 dBm, thus enabling spectrally efficient high-order modulation schemes such as 256-QAM. The I/Q modulator achieves 200 Gb/s in 16-QAM (50 Gbaud/s) while consuming 200 mW, resulting in record 1-pJ/bit modulation efficiency. In addition to backhaul links, the modulator is an attractive and cost-effective alternative to short-range optical links for data center interconnects (DCI) and for chip-to-chip communications.

Dual-Band Millimeter-Wave Quadrature LO Generation With a Common-Centroid Floorplan

This brief presents a dual-band millimeter-wave (mm-Wave) quadrature signal generation network comprising an RC-CR polyphase filter (PPF) and two quarter-wave coupled-line couplers. A common-centroid layout is proposed to improve the phase and amplitude matching of quadrature signals. The effects of interconnects and parasitic capacitances on PPFs are investigated, and design guidelines are provided to achieve low insertion loss and broad bandwidth. A proof-of-concept image-reject mixer is implemented in a 0.13 $ \mu \text{m}$ SiGe BiCMOS technology, which achieves a mean image-rejection ratio of 34 dB over a wide frequency range of 36 – 100 GHz. To the best of authors’ knowledge, this design achieves the widest bandwidth of any mm-Wave mixer having a mean image rejection ratio above 30 dB, and accomplishes this without calibration or tuning.

A CMOS Highly Linear Doherty Power Amplifier With Multigated Transistors

This paper presents a highly linear and power back-off efficiency-enhanced Doherty power amplifier (PA) fully integrated into CMOS. The proposed Doherty PA employs a transformer-based quadrature signal generator, multigated transistors (MGTRs) in the main PA, Class-C mode auxiliary PA, and synthesized transformer-based Doherty parallel output network with the second-harmonic control circuits. An on-chip 8-port transformer-based quadrature signal generator is designed within a single transformer footprint ( $340\,\,\mu \text{m}\,\,\times 340\,\,\mu \text{m}$ ) and provides 0°/−90° differential signals to the main/auxiliary PAs. The MGTR in the main PA is implemented using four transistors with different sizes and biases to generate and extend a near-zero $\text {g}_{\text {m3}}$ operation region. Moreover, an on-chip transformer-based Doherty parallel output network with the second-harmonic control circuits shows higher passive efficiency compared with a conventional Doherty parallel output network and provides low second-harmonic loads to the main/auxiliary PAs. Both the proposed MGTR in the main PA and the second-harmonic control circuits in the main/auxiliary PAs suppress the third-order intermodulation distortion of the Doherty PA. This results in a substantial linearity improvement of the Doherty PA, which can support high-order modulation signals and reduce or even eliminate the need for digital predistortion (DPD). As a proof-of-concept design, a 5.8 GHz Doherty PA is implemented in a standard 55 nm bulk CMOS process. The proposed Doherty PA exhibits 27.2 dBm saturated output power with 24.5% power-added efficiency (PAE) at 5.8 GHz. The measured error vector magnitude with 40/80 MHz of 64-QAM/256-QAM is 2.5%/1.8% with 20.7/17 dBm average output power, 9.5%/5.3% average PAE, and −33.2/−36.3 dBc adjacent channel leakage ratio without any DPD.

A Multiple Improved Notch Filter-Based Control for a Single-Stage PV System Tied to a Weak Grid

In this paper, a control scheme based on improvement in a generalized integrator is implemented on a three-phase single-stage grid-tied solar photovoltaic system with the distribution static compensator capabilities under grid abnormal conditions of voltage distortion and voltage unbalance. The photovoltaic voltage-source converter system compensating for the reactive power consumed by nonlinear load at point of common coupling provides load balancing and mitigates harmonics. The proposed multiple-improved-notch-filter-based quadrature signal generator control approach extracts the load current fundamental component, independent of the grid voltage. This control has better dc offset and harmonics component rejection capability in comparison to a conventional second-order generalized integrator algorithm. The perturb and observe-based maximum power point tracking algorithm is applied for the extraction of maximum power from the photovoltaic array. The system is analyzed under different abnormal conditions of voltage distortions, voltages unbalance, voltage swell, voltage sag, load currents unbalance, and insolation change on a prototype developed in the laboratory. The system performance is found to be satisfactory, within limits as described in an IEEE-519 standard while feeding active power to distribution network and connected loads.

Sensorless Control of Standalone Brushless Doubly Fed Induction Generator Feeding Unbalanced Loads in a Ship Shaft Power Generation System

The standalone brushless doubly fed induction generator (BDFIG) has demonstrated excellent energy-saving performance in ship shaft power generation applications. As a standalone system, it exhibits unbalanced terminal voltages and poor performance under unbalanced loads. However, the existing control scheme of grid-connected BDFIGs cannot be directly applied to stabilize the amplitude and frequency of terminal voltage when the rotor speed and electrical load vary. This paper presents a new sensorless control scheme for the standalone BDFIG under unbalanced load conditions in the ship shaft power generation system. A second-order generalized integrator-based quadrature signal generator is introduced to realize the rotor speed observer for the standalone BDFIG feeding unbalanced loads. The compensation method of negative-sequence power winding voltage is proposed to eliminate the negative-sequence component of the unbalanced power winding voltage. Comprehensive experiments are carried out on a prototype BDFIG with and without the compensation of negative-sequence power winding voltage. The good performance of the proposed sensorless control scheme is verified by the experimental test results.

A Low-Loss Broadband Quadrature Signal Generation Network for High Image Rejection at Millimeter-Wave Frequencies

This paper presents a broadband low-loss quadrature-hybrid-based network that enhances the phase and the amplitude matching of quadrature signals. The performance of this network is investigated, and a detailed theoretical analysis is provided. Several stages of this network can be cascaded to generate broadband balanced quadrature signals. Each stage has a loss of 0.5 dB and enhances the image rejection ratio (IRR) by approximately 8 dB. Compared with the conventional polyphase quadrature signal generation methods, the proposed network enables lower insertion loss, wider bandwidth, and reduced sensitivity to process variations. To verify the theoretical analyses, two proof-of-concept image-reject mixers are implemented in a 0.13- $\mu \text{m}$ SiGe BiCMOS technology. The first mixer achieves an average IRR of 37.5 dB across 40–76 GHz, whereas the second mixer achieves an average IRR of 33.5 dB across 40–102 GHz. The proposed network is a promising solution for broadband quadrature signal generation at millimeter-wave frequencies, as it eliminates the need for calibration and tuning.

A PVT-Tolerant >40-dB IRR, 44% Fractional-Bandwidth Ultra-Wideband mm-Wave Quadrature LO Generator for 5G Networks in 55-nm CMOS

Precise generation of quadrature signals over a wide frequency range is a key function for the next-generation 5G communication systems. In this paper, we present a wideband quadrature generator based on a single-stage polyphase filter (PPF). A phase detector senses the phase error from quadrature signals generated by a single-stage PPF, and a feedback circuit continuously tunes the filter center frequency to the input signal frequency by varying the polyphase resistance of an nMOS device in triode. Transformer-based resonant circuits at the input and output of the PPF ensure wide bandwidth and low loss. Prototypes have been realized in a 55-nm CMOS technology. Tailored to the next-generation 5G systems for cross-network interoperability requirements, the measured quadrature generator shows an image rejection ratio IRR > 40 dB over a bandwidth from 28 to 44 GHz. The power consumption is 36 mW for the PPF and buffers, and 3 mW only for the calibration loop. One key aspect of the proposed solution is its robustness over process, voltage and temperature (PVT), one of the weak aspects of alternatives proposed in the literature. This solution compares favorably with the state of the art and shows the largest fractional bandwidth (44%) among the quadrature generators at frequencies greater than 20 GHz, to authors’ knowledge.

A Direct Maximum Power Point Tracking Method for Single-Phase Grid-Connected PV Inverters

A direct maximum power point tracking (MPPT) method for PV systems has been proposed in this work. This method solves two of the main drawbacks of the perturb and observe MPPT, namely: 1) the tradeoff between the speed and the oscillations in steady-state and 2) the poor effectiveness in dynamic conditions, especially in low irradiance when the measurement of signals becomes more sensitive to noise. The proposed MPPT is designed for single-phase single-stage grid-connected PV inverters and is based on estimating the ripple of the instantaneous PV power and voltage, using a second-order generalized integrator-based quadrature signal generator. We analyzed the global stability of the closed-loop control system and validated the proposed algorithm through simulation and experiments on an inverter test platform according to the EN 50530 standard. The experimental results confirm the performance of the proposed method in terms of both speed and tracking efficiency.

A 38-GHz High-Speed I/Q Modulator Using Weak-Inversion Biasing Modified Gilbert-Cell Mixer

A 90-nm CMOS I/Q modulator with low dc-power consumption, low local oscillator (LO) power requirement, and high image reject ratio (IRR) is proposed in this letter. To minimize dc-power consumption and LO power requirement, the weak-inversion biasing technique is adopted in the switching transistors and the modified Gilbert-cell mixer structure is also applied to solve the voltage headroom problem in conventional Gilbert-cell mixer. Moreover, to demonstrate high IRR, a four-way quadrature signal generator with low phase and gain imbalance is implemented. With only 28.8-mW dc consumption and 0-dBm LO driving power, this I/Q modulator performs −2 ± 1-dB conversion gain and better than −35-dBc IRR from 34 to 39 GHz at 0.5-GHz IF frequency. Furthermore, due to the high IRR performance, 16-quadratic-amplitude modulation (QAM) and 256-QAM measurements with data rate of 4 and 1.6 Gb/s are successfully demonstrated at 38 GHz.

A CMOS Quadrature Signal Generator for Impedance Spectroscopy Measurement Systems

A CMOS fully integrated quadrature signal generator for on-chip impedance spectroscopy (IS) applications is presented. Frequency can be digitally tuned from 5 to 350 kHz with 12-bit resolution. Power consumption is 0.77 mW and active area is 0.129 mm2. Its suitability for the target application is validated with a Randles test impedance cell modelling a protein.

A CMOS Self-Contained Quadrature Signal Generator for SoC Impedance Spectroscopy.

This paper presents a low-power fully integrated quadrature signal generator for system-on-chip (SoC) impedance spectroscopy applications. It has been designed in a 0.18 μm-1.8 V CMOS technology as a self-contained oscillator, without the need for an external reference clock. The frequency can be digitally tuned from 10 to 345 kHz with 12-bit accuracy and a relative mean error below 1.7%, thus supporting a wide range of impedance sensing applications. The proposal is experimentally validated in two impedance spectrometry examples, achieving good magnitude and phase recovery results compared to the results obtained using a commercial LCR-meter. Besides the wide frequency tuning range, the proposed programmable oscillator features a total power consumption lower than 0.77 mW and an active area of 0.129 mm2, thus constituting a highly suitable choice as stimulation module for instrument-on-a-chip devices.

An Approach to Optimize Manufacture of an Active Quadrature Signal Generator Based on Heterostructures to Increase Density of Elements. Influence of Miss-Match Induced Stress and Porosity of Materials on Technological Process

An Approach to Optimize Manufacture of an Active Quadrature Signal Generator Based on Heterostructures to Increase Density of Elements. Influence of Miss-Match Induced Stress and Porosity of Materials on Technological Process

An Approach to Optimize Manufacture of an Active Quadrature Signal Generator Based on Heterostructures to Increase Density of Elements. Influence of Miss-Match Induced Stress and Porosity of Materials on Technological Process

An Approach to Optimize Manufacture of an Active Quadrature Signal Generator Based on Heterostructures to Increase Density of Elements. Influence of Miss-Match Induced Stress and Porosity of Materials on Technological Process

An Approach to Optimize Manufacture of an Active Quadrature Signal Generator Based on Heterostructures to Increase Density of Elements. Influence of Miss-Match Induced Stress and Porosity of Materials on Technological Process

An Approach to Optimize Manufacture of an Active Quadrature Signal Generator Based on Heterostructures to Increase Density of Elements. Influence of Miss-Match Induced Stress and Porosity of Materials on Technological Process

An Approach to Optimize Manufacture of an Active Quadrature Signal Generator Based on Heterostructures to Increase Density of Elements. Influence of Miss-Match Induced Stress and Porosity of Materials on Technological Process

An Approach to Optimize Manufacture of an Active Quadrature Signal Generator Based on Heterostructures to Increase Density of Elements. Influence of Miss-Match Induced Stress and Porosity of Materials on Technological Process

Разработка и исследование SiGe интегральных формирователей квадратурных сигналов L- и S-диапазонов

Разработка и исследование SiGe интегральных формирователей квадратурных сигналов L- и S-диапазонов

A Precision Wideband Quadrature Generation Technique With Feedback Control for Millimeter-Wave Communication Systems

An integrated two-stage polyphase filter (PPF) with feedback control for quadrature local oscillator generation at millimeter-wave frequencies is described. To minimize the in-phase (I) and quadrature (Q) mismatch, the second stage of the PPF utilizes triode-region nMOS transistors to implement variable resistors where the resistance is precisely controlled by modulating the shared gate-to-source bias voltage at the gate of nMOS devices. The gate bias voltage of the triode-region devices is set by a feedback loop which changes with variations in process, voltage, and temperature. A prototype quadrature signal generator, employing this PPF design, is integrated in a 28-nm LP CMOS process. A worst case measured phase/amplitude imbalance of 2°/0.32 dB (typical-typical corner dies) and 2.2°/0.55 dB (slow-slow corner dies) is reported over 7-GHz bandwidth for a fixed control current (ICtrl). By retuning ICtrl at every 7 GHz, this IQ generator would maintain the measured quadrature accuracy from 55 to 70 GHz. The core area occupied by the IQ generator circuitry is 20 μm × 40 μm and the device consumes less than 192 μW, of which 120/72 μW comes from the feedback control-loop/opamp, respectively. The proposed PPF method has a simulated input impedance of 150 Ω in-parallel with 18 fF.