Abstracts:In bidirectional inductive power transfer (BIPT) systems, phase synchronization loop that keeps the secondary-side excitation voltage synchronized with the current is essential for stable power transmission. However, the characteristic of control object in the synchronization loop can vary due to the variation of the operating point parameters (OPPs), which can lead to loop instability. In this article, the transfer functions of the control object and the phase detector in the phase synchronization loop are derived. The influence of the variation of OPPs on the transfer function of the control object is analyzed. The transfer function is mainly affected by one zero that is sensitive to the OPPs and can shift into low-frequency region, while the other poles and zeros are at high frequencies and have less influence. The phase synchronization controller is designed considering the variation of OPPs to ensure the stability of the system in a wide range of OPPs. The sensitivity of the loop to the OPPs is analyzed. Frequency response results from simulation and experiment have verified the correctness of the model, and the stability of the loop. Steady-state and transient experiments prove the stable steady-state performance and fast transient response of the system.

Abstracts:In this article, a structure-reconfigurable series resonant DC-DC converter is proposed for a wide gain on-board charger application. The proposed converter consists of a dual-bridge structure on the primary side which can realize 0.5 to 1 voltage gain by using a reconfigurable half/full bridge structure, and a hybrid rectifier on the secondary side which can realize 1 to infinite voltage gain by replacing two diodes with active switches. Moreover, the proposed converter employs a control scheme based on fixed frequency PWM, with the operating frequency being identical to the series resonant frequency. Accordingly, magnetizing inductance of the transformer is independent of the converter gain characteristics, which simplifies the consideration of the resonance parameters design. In addition, soft switching can be realized during the entire charging process, and high efficiency can be achieved. To avoid the voltage spike and current impact in the transition between two operation modes, a unified switching modulation strategy is applied to achieve a smooth transition and improve the control stability. Finally, a 2.5 kW prototype with an output voltage range of 200V - 500 V is established and tested to verify the effectiveness and feasibility of the proposed converter.

Abstracts:The application of federated learning in Virtual Power Plants (VPPs) addresses the data silo issue between VPPs and enhances their ability to cope with nonlinear and stochastic scheduling characteristics, which enables VPPs better accommodate distributed energy resources and flexible loads while participating in frequency regulation services. However, although existing federated learning methods strive to solve privacy protection issues, the plaintext transmission of gradients still exposes sensitive data to the threat of curious power control centers and external inference attacks. Therefore, a privacy-protected horizontal federated reinforcement learning approach for multi-VPP optimal scheduling is proposed in this paper. Firstly, a cost-based global optimization scheduling model for multiple VPPs is constructed, modeling the internal scheduling process of VPPs as a Markov decision process. Then, an improved secure horizontal federated multi-VPP collaborative training method is presented, and local models are trained using the Deep Transformer Q-Network algorithm, with local differential privacy and CKKS homomorphic encryption implemented to ensure privacy protection. Finally, a case study is conducted using frequency regulation ancillary service market data and the IEEE-39 bus system structure. Simulation results show that the proposed approach outperforms similar algorithms, achieving high levels of privacy protection and economic operation for VPPs.

Abstracts:In this paper, the small signal model for a four-level flying capacitor multilevel (FCML) totem-pole PFC converter is presented. In contrast to conventional PFC converters, the state space equations for the FCML PFC converter in a complete switching cycle change over the line cycle. If the standard state space averaging technique is applied, it will only evaluate a single combination of state space equations corresponding to only one segment of the line cycle. Since the four-level FCML PFC converter consists of three different segments in one half-line cycle, this technique is not applicable to derive a comprehensive small signal model of the converter that is required for regulation and transient stability. Moreover, the effects of flying capacitors on the FCML PFC dynamics are nulled out using the average model due to their natural balancing capability. In this work, the Fourier analysis of time-interval modulated switched network is used to determine the closed form small-signal control to output frequency response and verify its accuracy with the experimental results. The dynamic characteristic of the FCML converter is also evaluated for the variations in the converter passive elements. Finally, a hardware prototype is designed, fabricated, and tested for ac input 120 Vac, 400-V dc output, and 1-kW power rating demonstrating peak efficiency of 98.48%, power factor 0.995 and THD of 4.26% to observe the system behavior under load step changes.

Abstracts:Virtual synchronous generator (VSG) controlled isolated power grid has been widely concerned because of its advantages of voltage support. However, in the presence of significant disturbance, the system would face the risk of transient instability like conventional power grid. As a recently developed control method, phase sequence exchange (PSE) can not only stabilize the system but also avoid additional reduction in system capacity and inertia. Nonetheless, PSE increases redundant power electronic devices into the grid. Therefore, this paper establishes a transient model for VSG-controlled isolated power grid initially. Based on this, a control method is proposed to realize the effect of PSE by reducing the power angle of VSG through power electronic control in the inverter, named as virtual phase sequence exchange (VPSE). This control method effectively avoids the need for external PSE devices while improving the transient stability. Furthermore, this paper investigates the VPSE technology through the extended equal area criterion (EEAC) and modern control theory, with results indicating that compared to PSE, VPSE has better transient control effects. Finally, the proposed scheme is verified by physical experiments on the real-time digital simulation platform (RTDS).

Abstracts:Modular multilevel converters (MMCs) obtain widespread utilization in high-voltage direct current (HVdc) applications scenarios. The cost of power losses plays a significant part in MMC’s operating costs. Hence, this article proposes a quantum genetic algorithm-based power losses optimization control (QGA-PLOC). By comprehensively considering the power losses of the MMC, the quantum genetic algorithm determines the first-best value of the injected second circulating current magnitude and phase angle in the arm, as well as the optimal MMC power losses under given conditions. The quantum genetic algorithm incorporates the quantum state vector representation into genetic encoding and utilizes quantum logic gates for chromosome evolution, greatly improving the algorithm’s performance and significantly enhancing its computational efficiency and global optimization capability. Moreover, introducing the quantum genetic algorithm into the field of MMC power losses optimization offers a new path to address the acquisition of the optimal circulating current reference value in power loss optimization problems. MMC Simulation and experiment are also conducted, and the research results verify the effectiveness of the proposed QGA-PLOC for MMCs.

Abstracts:This paper proposes a novel and efficient model for the estimation of post-FEC BER for high-speed serial links using FEC codes such as RS (544, 514) in the presence of DFE error propagation. The model employs the Markov model for DFE error propagation and incorporates concepts from the Gilbert-Elliott model. Using various optimization techniques, including Markov state aggregation, burst tables, and adaptive neglect of rare cases, it achieves a computation time that is only 1.658% of that required by previous work for the post-FEC BER computation with RS (544, 514) FEC code and a 2-tap DFE. Furthermore, analyses demonstrate that its computation time increases less rapidly with respect to the number of DFE taps compared to previous works, indicating its better applicability for systems with more DFE taps or larger state spaces. Data measured from an FPGA-based behavior simulator proved that the model can accurately estimate post-FEC BER.

Abstracts:In this paper, we present an ultra-low power wake-up receiver (WuRX) with effective interference suppression capability. A specific robust design has been implemented to address the common interference issues in the industrial, scientific, and medical (ISM) frequency band. A mathematical expression is derived in this paper for the minimum signal-to-noise ratio (SNR) required by the comparator at which a envelope detector first (ED-first) WuRX can detect the wake-up message in the presence of interference. Aiming to meet the minimum SNR requirements, a quasi-direct coupling (QDC) baseband buffer scheme is proposed. Compared to the output SNR of traditional AC schemes, the QDC baseband buffer scheme achieves a 4.16 dB increase in output SNR under optimal conditions. To solve the problem where traditional comparator calibration schemes require recovery time after sudden disappearance of interference, the multipath signal detection (MPSD) scheme proposed in this paper can immediately detect information following the disappearance of interference, which improves detection efficiency. The WuRX is manufactured in 65nm LP process, consuming 7.56nW at a 0.4V power supply, with a sensitivity of −79dBm in the 433MHz ISM band. Under continuous wave (CW) interference, the receiver achieves a signal-to-interference ratio (SIR) of −31dB at a frequency offset of 1MHz.

Abstracts:This paper describes an adaptive duo-binary four-level pulse amplitude modulation (Duo-PAM4) detector that significantly reduces the bit error rate (BER) of the conventional wireline transceivers under high insertion loss (IL) channels. The parallel maximum likelihood sequence detection (MLSD) combined with parallel feed-forward equalization (FFE) is proposed to generate, equalize, and detect Duo-PAM4 signals, thus reducing BER compared to conventional decision feedback equalizer (DFE) and slicers. The proposed reduced branch MLSD reduces power consumption compared to MLSD. An improved delay zero-forcing algorithm for Duo-PAM4 is proposed to achieve fast convergence of the FFE tap coefficients, reducing convergence time by up to 72.5% compared to conventional ZF algorithms for Duo-PAM4. Both the proposed and conventional detectors are implemented in a 28-nm CMOS process at 56 Gb/s and 38-dB insertion loss. The FFE+MLSD and FFE+RB-MLSD reduce the BER by two orders of magnitude compared to conventional FFE+DFE+slicer. The RB-MLSD reduces power consumption by 21.1% compared to conventional MLSD. The detector can be easily migrated to 112Gb/s or 224Gb/s transceivers.

Abstracts:In this paper, a cloud-edge model predictive control (MPC) framework is proposed for cyber-physical systems in the presence of deception attacks and Denial-of-Service (DoS) attacks. In the proposed framework, the original MPC optimization problem is decomposed into cloud and edge layers by using an efficient parameterized control input sequence. Then, a novel controller updating mechanism is developed by discontinuously comparing the optimal value functions of the modified optimization problem and the original optimization problem, which saves the communicational and computational resources. Specifically, the control performance is optimized over all possible uncertainties and deception attack realizations using a min-max optimization technique, while the DoS attacks can be tackled with the parameterization feature of the control input sequence. Besides, the closed-loop system is guaranteed to be input-to-state practical stable (ISpS) under the proposed MPC strategy. Simulation studies and comparisons are performed to verify effectiveness of the proposed method.