Delay Compensation Research Articles

A Picosecond Delay Generator Optimized by Layout and Routing Based on FPGA

A delay generator is a timing control device that can generate a delay for the input signal according to the actual requirements. A delay generator with a combination of rough delay and precise delay is implemented on a Xilinx Kintex-7 series FPGA with a design scheme based on carry delay chain. The delay generator uses the delay time parameters sent by the upper monitor to work and to reflect the current working state to the upper monitor. In this article, a theoretical model of the delay generator is designed, and a delay compensation scheme is proposed to make the working state of the theoretical model closer to the actual circuit. Through simulation experiments, the time resolution of the delay generator is 54 ps, and the time accuracy is less than 50 ps. The delay scheme adopted in this article is highly scalable, and the time resolution and time accuracy can be further improved. Finally, a theoretical model of the delay generator with relatively high time resolution is implemented through low resource occupancy rate and little workload.

Optimal control of wind farm power output with delay compensated nested-loop extreme seeking control

In this paper, we propose to enhance the nested-loop extremum seeking control (NLESC)-based wind farm control strategy with the predictor-based delay compensation in order to improve its convergence characteristics under fluctuating wind. Earlier work has shown the effectiveness of NLESC for region-2 wind farm operation, i.e., maximizing the total power output of cascaded wind turbine array, while its convergence speed is highly limited by the delay of power output for downstream turbines due to wake propagation along the wind direction. By utilizing the delay compensated ESC proposed by Oliveira and Krstic, the delay compensated NLESC (DCNLESC) wind farm control is proposed, allowing the dither frequencies to be of similar magnitude as that in the single-turbine ESC. This can significantly improve the convergence speed of optimum tracking for real-time wind farm control. The wake propagation delay is estimated from turbine power outputs using cross correlation and proper filtering. Using the SimWindFarm platform, the proposed DCNLESC strategy is simulated with both a single-column three-turbine array and a 2 × 3 turbine array, under different wind speeds. The results show that the convergence speed toward the calibrated optimum is significantly improved over the NLESC operation. The convergence time for the upstream turbines' torque gain is reduced by 55%–14% in terms of integral time-weighted absolute error, while the impact on turbine fatigue loads is as low as no more than 3.5% increase on turbine tower and shaft.

Cloud Control of Connected Vehicle Under Both Communication-Induced Sensing and Control Delay: A Prediction Method

In this paper, we focus on the problem of cloud control of the connected vehicle with time-varying communication-induced sensing delay and control delay. First, the connected vehicle cloud control system containing communication-induced delay is modeled as the discrete linear output feedback system with bounded input and output delay. Second, corresponding to the linear output feedback system, the “predictor-observer” structured controller is introduced and redesigned to compensate for the delay in both output and input channels actively, without measurement of actual input delay as its original version. The stability of the close-looped prediction-based control system under a certain delay boundary is analyzed, and the sufficient stability condition is proposed. Third, with the help of Cone Complementary Linearization (CCL), an iterative algorithm is proposed to design stabilized controller and observer gains. Finally, the proposed method is verified through vehicle lateral and longitudinal control simulations, and the effectiveness and the performance of the proposed delay compensation strategy are innovatively evaluated under real vehicle control scenarios.

Multi-Modal Sensor Fusion and Object Tracking for Autonomous Racing

Reliable detection and tracking of surrounding objects are indispensable for comprehensive motion prediction and planning of autonomous vehicles. Due to the limitations of individual sensors, the fusion of multiple sensor modalities is required to improve the overall detection capabilities. Additionally, robust motion tracking is essential for reducing the effect of sensor noise and improving state estimation accuracy. The reliability of the autonomous vehicle software becomes even more relevant in complex, adversarial high-speed scenarios at the vehicle handling limits in autonomous racing. In this paper, we present a modular multi-modal sensor fusion and tracking method for high-speed applications. The method is based on the Extended Kalman Filter (EKF) and is capable of fusing heterogeneous detection inputs to track surrounding objects consistently. A novel delay compensation approach enables to reduce the influence of the perception software latency and to output an updated object list. It is the first fusion and tracking method validated in high-speed real-world scenarios at the Indy Autonomous Challenge 2021 and the Autonomous Challenge at CES (AC@CES) 2022, proving its robustness and computational efficiency on embedded systems. It does not require any labeled data and achieves position tracking residuals below 0.1 m. The related code is available as open-source software at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/TUMFTM/FusionTracking</uri> .

A 254-nW 20-kHz On-Chip RC Oscillator With 21-ppm/°C Minimum Temperature Stability and 10-ppm Long Term Stability.

This paper presents a temperature compensated RC oscillator (TC-RCO) designed in 130 nm CMOS technology using regular transistors. The TC-RCO uses constant transconductance biasing for first order temperature compensation. Device mismatch based offset correction and delay compensation techniques in the comparator are used to improve temperature instability by cancelling out second order effects. The oscillator achieves a minimum temperature stability down to 21 ppm/°C for a temperature range of -20 to 100 °C. In the lowest power mode, the oscillator consumes 254 nW power with a 1 V supply. The TC-RCO is operated in two modes, a low power mode that consumes an average of 254 nW and a high stability mode that consumes an average of 345 nW. A duty-cycling technique is used to correct offset after four cycles of oscillation. The oscillator exhibits long term stability of 10 ppm after 1 s integration time.

Robust Deadbeat Predictive Direct Speed Control for PMSM With Dual Second-Order Sliding-Mode Disturbance Observers and Sensitivity Analysis

A novel robust deadbeat predictive direct speed control (RDP-DSC) method for permanent magnet synchronous motor (PMSM) is proposed to improve the speed control bandwidth and eliminate the conventional cascaded speed control structure. Firstly, the basic DP-DSC method with one-step ahead time delay compensation is introduced briefly. Then, the control sensitivity analysis issue on the electrical and mechanical parameter mismatches, external disturbance, and inverter nonlinearity are inspirationally discussed. Further, based on the analysis above, a novel dual second-order sliding-mode disturbance observer (SOSMDO) structure is proposed for both current and speed disturbance suppression. The proposed RDP-DSC equipped with SOSMDO is presented with full control errors completely compensated. Meanwhile, the undesired chattering phenomenon caused by the switching function in the existing popular sliding-mode observers is eliminated by the proposed SOSMDO. Rich experiments are then performed, showing that the proposed method has strong enough robustness to various parameter mismatches and external disturbances while the system still holds the direct speed control methods' advantages, such as high response speed and satisfying bandwidth.

Control of a transformerless static synchronous series compensator for unbalanced voltage compensation

AbstractThis paper explores a transformerless static synchronous series compensator (TL‐SSSC) for mitigating voltage distortion in a power distribution line with renewable generations. A novel deadbeat current control scheme with time delay compensation is proposed which models the a‐b‐c three phase line with TL‐SSSC plus its LC filters and predicts the compensating voltages to be injected by the TL‐SSSC. Without resolving measured voltages and currents into positive and negative sequences, the scheme is computationally efficient and effective in mitigating voltage distortion due to faults occurring at different locations along the distribution line. It also eliminates the problem of inaccurate compensation voltage caused by inverter filter choking voltage drop. The paper also analyses the power controllable ranges for a TL‐SSSC under different unbalanced voltage ratios. The proposed TL‐SSSC and control scheme is validated using Typhoon Hardware‐In –Loop (HIL) device. Experimental results on mitigation unbalanced voltages of a 11kV transmission line confirm the effectiveness and high performance.

Research on control strategy for improving stability of multi-inverter parallel system under weak grid condition

Under weak-grid condition, the mismatch degree between grid impedance and inverter output impedance can increase, which will lead to inverter instability. Compared with conventional power grid, the parallel resonance of multi-inverter parallel system is more likely to happen. In order to improve inverter stability and suppress multiple-inverter parallel resonance under weak-grid condition, a new generalized control mode for control layer is proposed in this paper, which is based on finite set model predictive control (FCS-MPC) and inverse dynamic model control (IDM). The FCS-MPC with delay compensation is introduced into the current inner loop of the control layer, and the IDM control is introduced into the voltage outer loop, so as to make the transfer functions of current inner loop and voltage outer loop unitized and further reduce the order of the inverter’s control system. Order reduction can improve the phase margin of the inverter output impedance, in other words, enhance inverter dynamic performance. Finally, the simulation model of multi-inverter parallel system is built, and by comparing with the traditional control strategies, the effectiveness of the proposed control strategy is verified.

Enhancing Power Generation Stability in Oscillating-Water-Column Wave Energy Converters through Deep-Learning-Based Time Delay Compensation

Oscillating-water-column wave energy converters (OWC-WECs) are gaining attention for their high energy potential and environmental friendliness. However, their irregular input energy characteristics pose challenges to achieving stable power generation, particularly due to high peak power compared to average power. This study focuses on stable rating control to enable continuous power generation in the presence of irregular wave energy. It is difficult to precisely configure the existing rated power controllers due to physical time delays; this impacts system stability and utilization. To address this, we propose a rated power controller that compensates for system time delays using a deep learning algorithm. By predicting the valve control angle in advance and analyzing the input data for angle estimation, we successfully compensate for the physical time delay. The performance of the proposed rated power controller, incorporating the deep learning algorithm, is evaluated by analyzing the algorithm’s error rate. The results demonstrate that the proposed method improves power generation under various wave conditions by compensating for the unavoidable time delay of OWC-WECs, leading to a significant increase in annual power generation. In conclusion, the proposed method achieves approximately 31% higher annual power generation compared to the time delay controller.

Two networked predictive control methods for output tracking of networked systems with plant-model mismatch

This paper addresses the output tracking control problem for networked systems with plant-model mismatch, where two-channel random network delays are considered. According to the different ways of obtaining future control commands, two networked predictive control (NPC) methods are designed. One is the NPC method using one-way time delays, called ONPC, and the other is the NPC method using round-trip time delays, called RNPC. Furthermore, they are compared in terms of the way of compensation for two-channel delays, prediction process, and communication load, respectively. Then, the closed-loop stability conditions of the RNPC system and the ONPC system for the plant-model mismatch and match cases are derived, and their output tracking performance is also theoretically analysed. Finally, the results of the theoretical analysis are verified through numerical simulation that illustrates the effectiveness of the proposed two NPC methods as well as their separate advantages.

Model predictive control of a semi-active suspension with a shift delay compensation using preview road information

This paper presents a model predictive control of a semi-active suspension with a shift delay compensation using preview road information. A Model Predictive Control (MPC) methodology has been developed to optimize both ride comfort and road handling performance, where suspension states have been estimated through a model-based Kalman filter. The use of MPC in semi-active suspension control has proven to be suitable due to its ability to consider constraints when optimizing the objective function. A feasible region for the control inputs into the semi-active suspension has been determined from its mechanical limitations. However, the proposed Model Predictive Controller carries a sizeable computational load. Occurrences of “shift time delays” have been observed from the vehicle’s Electronic Control Unit processing the algorithm. To combat this, a model prediction system, in which a full-car dynamic model and road preview information are utilized to predict vehicle suspension states, has been further proposed to compensate for the shift time delay. Preview road information has been obtain through the computation of relative vehicle motion and a temporal–spatial conversion. The overall algorithm has been evaluated via computer simulation studies. Simulation results have shown that the shift compensation algorithm provides considerable improvements with regards to ride comfort. A noteworthy section of this study is the successful implementation of the proposed algorithms into an actual vehicle, where the real world performance of the proposed algorithms have been assessed. It has been shown via vehicle tests that significant improvement in ride comfort can be obtained by the proposed MPC damping control.

SR Control With Zero Current Detection Delay Compensation for GaN CRM Totem-Pole PFC Rectifier

An SR control with ZCD delay compensation is proposed to reduce the high reverse inductor current and input current distortion caused by the zero current detection (ZCD) delay in critical mode totem-pole power factor correction (PFC). The basic idea of the proposed control is to calculate the SR turn-off instant considering the ZCD delay. Accurate operation model in VOT control is analyzed with ZCD delay compensation to realize the proposed control. A prototype of 2 kW GaN CRM totem-pole PFC converter is built to verify the proposed control. The total harmonic distortion (THD) with full load decreases to 3% by mitigating the current distortion caused by the ZCD delay, 1.6% lower than that before compensation. The high reverse inductor current near the zero-crossing of input voltage is avoided since the length of the zero-current platform is shortened by 87.5%. The prototype achieves 99% efficiency at full load (2 kW) and a power density of 120 W/inch <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> .

A Digital Frequency-Dependent I/Q Imbalance and Group Delay Estimation and Compensation Modules for mmWave Single Carrier Baseband Transceivers

This paper proposes the estimation and compensation modules of digital frequency-dependent (FD) I/Q imbalance and group delay for single carrier (SC) mode with 15 Gbps throughput rate in the millimeter-wave (mmWave) band. The proposed compensation module of a digital recursive filter can mitigate FD I/Q imbalance effects caused by the -3 dB corner imbalance of the reconstruction and anti-aliasing filters of I/Q branches. The proposed recursive filter with the appropriate initial coefficients based on the result of Golay sequence estimation can shorten the convergence time and precisely acquire the desired coefficients. The average image rejection ratio (IRR) performance after compensating by the proposed module can be improved from 21.97 dB to 47.54 dB. Besides, the group delay distortion in reconstruction and anti-aliasing filters will cause intersymbol interference to distort the in-band signal. We employ a digital equalization filter with the filter coefficients derived from the correlation results based on the Golay sequence to compensate the in-band group delay distortion. After the proposed group delay is pre-compensation at TX, the system-level performance of error vector magnitude (EVM) performance is improved by 6.21 dB to -27.78 dB to satisfy the IEEE 802.11ad/ay requirement in 64-QAM mode. The inner RX BER performance with the FD I/Q imbalance and the group delay compensation modules can achieve 3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> at 23 dB and also satisfy the system requirement at SNR of required 25.52 dB. A four-times parallelism architecture is proposed to work at a clock rate of 625 MHz with 64-QAM mode. The gate count and power consumption of the proposed design are 154.4 K and 16.2 mW, respectively.

Generating six pairs of bandwidth-expanded entangled sideband modes via time delay compensation.

Quantum entanglement is an important pillar of quantum information processing. In addition to the entanglement degree, the bandwidth of entangled states becomes another focus of quantum communication. Here, by virtue of a broadband frequency-dependent beam splitter, we experimentally demonstrate six pairs of independent entangled sideband modes with maximum entanglement degree of 8.1 dB. Utilizing a time delay compensation scheme, the bandwidth of independent entangled sideband modes is expanded to dozens of megahertz. This work provides a valuable resource to implement efficient quantum information processing.

Group delay compensation based on negative group velocity effect of spoof surface plasmon polaritons

Negative group velocity (NGV) exists only in the anomalous dispersion band with resonance absorption. In this paper, it is verified that spoof surface plasmon polaritons (SSPPs) with spiral-shaped periodic units have the NGV characteristics near cutoff frequency. The negative group delay of this NGV SSPP can be used to achieve the compression of the pulse signal, and also to compensate the positive group delay with high efficiency. Of course, this group delay compensation scheme based on NGV may introduce an absorption loss, which is the characteristic of all passive negative group delay circuits.

A 24-kHz BW 90.5-dB SNDR 96-dB DR continuous-time delta-sigma modulator using FIR DAC feedback

This paper presents a single bit continuous time delta-sigma modulator (CTDSM) with finite impulse response (FIR) feedback DAC designed for audio applications. By using FIR feedback in the input stage, the linearity requirements of the first integrator are relaxed, and the clock jitter sensitivity is reduced, as seen in a multi-bit quantizers. The choppers, working in conjunction with the FIR DAC, effectively suppresses in-band aliasing noise generated by the chopper in the first integrator. A fast comparator serves as a single-bit quantizer, and the 9.2% TS loop delay eliminates the need for excess loop delay compensation in the modulator. Energy efficient integrators are implemented using the current-starved OTA. The CTDSM prototype was fabricated using a 180-nm CMOS process, achieving a 90.5 dB SNDR and 96 dB DR with a 24 kHz signal bandwidth. The power consumption is 210 μ W, corresponding to a Schreier figure-of-merit value of 171.1 dB.

A K-Band Series-Fed WR42 Waveguide Horn Array with Beam Squint Reduction through Shunt Delay Sections

Series feeds are commonly used in antenna arrays because of their compact size and low loss compared to corporate feeds but typically feature beam squint over wide bandwidths. This work proposes a series-fed waveguide horn array with reduced beam squint by introducing synthesized time delay sections between the horns and the feed line. The array, implemented in a WR42 waveguide, achieves 1.53° beam squint over a 4 GHz operating band, compared to 10.52° for a reference design without time delay compensation.

Delay Compensation of Neutral-Type Time-Delay Control Systems by Cascaded-Observers

Delay Compensation of Neutral-Type Time-Delay Control Systems by Cascaded-Observers

Overview of Predictive Control Technology for Permanent Magnet Synchronous Motor Systems

Permanent magnet synchronous motors (PMSMs) are commonly used in the automation industry. With the speedy development of digital system processors, predictive control as a modern control scheme has been applied to improve the dynamic performance and work efficiency of PMSMs. This paper provides an overview of the research status of PMSM-based predictive control strategies. The deficiencies of the three most popular predictive schemes, deadbeat predictive control, finite-control-set model predictive control, and continuous-control-set model predictive control, and existing improvement strategies such as delay compensation schemes, robust control schemes, and multi-vector control schemes, are summarized. Finally, current technological trends are discussed, emphasizing future research directions for predictive control in PMSM drive systems.

Analisis Penanganan Kompensasi Delay pada Maskapai Lion Air terhadap Kepuasan Penumpang oleh PT Kokapura di Bandar Udara Jenderal Ahmad Yani Semarang

&#x0D; Delay is a state of delayed flight at an airline. Delay compensation is the provision of compensation to passengers if there is a flight delay either in the form of goods or money in accordance with Ministerial Regulation Number 89 of 2015. The purpose of this research is to find out whether there is an effect between the provision of delay compensation on satisfaction passengers, and to find out whether passengers are satisfied with the provision of compensation according to PM Number 89 of 2015. The method used in this research is a quantitative method. The population in this study were passengers from Lion Air at Jenderal Ahmad Yani Airport, Semarang with a sample of 100 respondents. Data collection was carried out by observing and distributing questionnaires (questionnaires). In this study, data analysis used a one-sample test analysis calculation and a simple linear regression test. The results of this study state that the provision of delay compensation to passengers is in accordance with PM Number 89 of 2015. Based on the results of the t-test it can be stated that there is an effect of handling delay compensation on passenger satisfaction at Lion Air Airlines at Jenderal Ahmad Yani Airport, Semarang. While the one-sample test results that passengers are satisfied with the handling of the delay compensation provided in accordance with PM Number 89 of 2015.&#x0D; Keywords: delay compensation, passenger satisfaction, one sample test analysis and simple linear regression analysis.