Jun Zeng

A Unified Phase-Shift Modulation for Optimized Synchronization of Parallel Resonant Inverters in High Frequency Power System

High frequency alternating current (HFAC) has already been applied in many power distribution systems due to outstanding merits. The circulation current control of the high frequency resonant inverter in parallel connection is more complicated than the low frequency counterpart. Methods from topology, modulation, and control perspectives have already been proposed; however, most of them are difficult to simultaneously accomplish the synchronization of magnitude and phase in high frequency circumstance. In this paper, a new modulation called as unified phase-shift modulation (PSM) is proposed to integrate the regulations of magnitude and phase. The unified PSM in steady state completely removes the modulation coupling between magnitude and phase so that the controllers of magnitude and phase can be independently accomplished without interactions. The operation scope of unified PSM is determined by zero voltage switching and total harmonic distortion of the resonant inverter. A prototype with two parallel inverters is established to verify the effectiveness with an operation frequency of 25 kHz and a full bridge output voltage of 40 V peak. The results of simulation and experiment prove that the unified PSM is superior over the existing PSM in HFAC circumstance. The controllers of magnitude and phase integrated by the proposed modulation can accomplish optimized output synchronization in the parallel single-stage resonant inverter.

Operational optimization of a stand-alone hybrid renewable energy generation system based on an improved genetic algorithm

In a hybrid renewable energy power generation system, optimization and control is a challenging task because the behaviors of the system are becoming unpredictable and more complex. After the system is built, optimization and control of its operation is important for utilizing the renewable energy efficiently and economically. In the paper, an improved genetic algorithm is developed for achieving the optimization of the hybrid RE system by considering its operation during its life-time. The proposed algorithm is validated by performing a scenario simulation and the results show that the improved genetic algorithm has better convergence speed or accuracy than those of the standard genetic algorithm.

A phase synchronization control scheme for LCL-T type high-frequency current source in parallel connection

Summary nConsidering the applications of high voltage gate driving system and contactless power transmission, a current-based power distribution is adopted as a kind of replacement of voltage based high-frequency Alternating Current (AC) power distribution system. In order to implement high-frequency current source, an LCL-T resonant inverter is examined with constant current characteristic and high conversion efficiency. First, the resonant topology is studied as a high-frequency power source, including circuit principle, operational cycle analysis, and AC analysis. The effective control and high conversion efficiency are both achieved by LCL-T resonant inverter. Second, the phase angle control scheme is explored to improve the synchronization performance in parallel system formed by multiple of LCL-T resonant inverters. Lastly, a prototype of parallel system is evaluated by simulation and experiment results, both of which are constructed by two resonant inverters with rated peak current of 2u2009A, rated output frequency of 30u2009kHz, and rated output power of 100u2009W. The experimental results in accordance with simulation prove that the better phase synchronization of output currents is achieved by the phase angle control. Hence, the high-frequency resonant topology and phase control scheme are a feasible realization of current source that can be used to feed current-based high-frequency power distribution system. Copyright

A novel multi-sensors fusion framework based on Kalman Filter and neural network for AFS application

An adaptive front light system (AFS) is put forward by the Society of Automotive Engineers and Economic Commission for Europe as a means of enhancing vehicular lighting. Traditionally, AFS can be divided into three parts: (1) a leveling subsystem to make lighting parallel to the road surface; (2) a swiveling subsystem to change light distribution along with the angle of the steering wheel; (3) a dimming subsystem to reduce or intensify the lighting. In this paper, a new hybrid multi-sensor fusion framework combining Kalman Filter with neural network is proposed to adjust two stepper motors controlling the vehicles headlights pitch and yaw. Kalman Filter as the frontend is used to deal with redundant sensor signals that are collected from sensors in the different places. Fuzzy Neutral Network as the backend is used to generate adjustment of leveling and swiveling angle through the integration of different type signals. An adaptive parameter adjustment is accomplished by the proposed fusion framework with the varying filter coefficients. The simulation and experiment of leveling angle are conducted using the predefined experimental data. The evaluation results of leveling angle prove that the proposed algorithm can effectively filter out high-frequency perturbations and provide reliable outputs for stepper motor. The same results can be obtained for a swiveling subsystem. Consequently, the hybrid fusion framework is a feasible approach for AFS design to accomplish data processing and nonlinear mapping.

The study of distributed EV charging station based on network

In order to reduce carbon emission, the world wide is developing novel electrical vehicle (EV) application. The battery and charging technology development is the most difficult breakthrough for EV promotion, wherein the design of convenient and reasonable charging station is critical to implement a sound charging system. This paper firstly introduces the development of Hongkong local charging station, and then proposes the distributed charging station network based on communication hierarchy. Finally, the state of charging (SoC) evaluation based on hybrid mode is presented. The deployment of charging station network testified distributed charging station network can effectively provide electricity to EV and centralized monitor the charging state. In the future, the proposed charging station network will has a broad application in Hong Kong market.

An integrated controller for high-frequency LCLC resonant inverter with phase-shifted control and frequency regulation

High-frequency alternating current has an extensive application as a result of outstanding advantages. The aim of the study is to develop a high-frequency power source to feed the auxiliary loads of vehicle application such as electric fans, blower motors, and lighting. A feasible implementation of high-frequency power source is examined by a full-bridge LCLC resonant inverter. The corresponding control scheme is proposed for the fourth-order resonant inverter to confront the control challenges of low output harmonics and dynamic nonlinear load. Firstly, an analysis parameter Sr is defined to address the possible impacts of the varying operational frequency to output THD and ZVS features. Secondly, an integrated control scheme is presented to implement pulse-width control at heavy load and frequency regulation at light load. Lastly, an experimental prototype is accomplished with the peak voltage of 35V and the output power of 120W. The accordance of experimental results and theoretical analysis testifies that the proposed control scheme can achieve the low harmonics and high conversion efficiency over a wide scope of operational conditions. Copyright

Some considerations of arc protection and breaker design for high frequency AC power distribution systems

High frequency power distribution already has a numerous applications in electric vehicle, renewable energy microgird, and telecommunication system. In order to propel high frequency power distribution into larger power grade, an effective ac arc protection scheme is significant for safety and reliability. However, almost all of the studies of arc fault are focused on dc or low frequency ac (LFAC). This paper presents protection scheme and examines electrical characteristics for high frequency arc fault. Meanwhile, high frequency breaker is examined with ZCS feature, and residual current devices (RCD) design is explored for high frequency power distribution as well. First, the location of arc fault detector (AFD) and interrupting devices (ID) is studied from system level; and the single phase arc grounding fault is analyzed for high frequency sinusoidal waveforms. Second, zero-current-switching (ZCS) feature of high frequency breaker is discussed from monitor circuit and breaker circuit. Third, trigger deficiency of high frequency RCD is demonstrated and corresponding solution is examined. Lastly, the simulation results further testify the effectiveness of theoretical analysis.

Sliding-mode control of phase angle in single-stage resonant inverter using unified phase-shifted modulation

In the view of the outstanding advantage, high frequency AC (HFAC) power distribution system (PDS) has already an extensive application from telecommunication system to electric vehicle. Resonant inverter as the high frequency power source provides fixed frequency output for point of load (POL). The controller designed with ever increasing frequency becomes more complicated, because the robustness and dynamic performance will deteriorate so as to greatly affect the stability of resonant converters. A sliding mode controller of phase angle is proposed for full-bridge series-parallel resonant inverter with unified phase-shift-modulation (PSM). The proposed nonlinear controller can effectively cooperate with the conventional controller of output magnitude to improve system robustness and dynamic performance. Furthermore, a simulation prototype is implemented for performance evaluation with a rated output power of 120W and operation frequency of 25 kHz.