Current Issue : January - March Volume : 2020 Issue Number : 1 Articles : 5 Articles
This paper proposes an inductive power transfer (IPT) system with three-bridge switching \ncompensation topology. With the proposed IPT topology, the equivalent circuit and the resonant \ncondition are analyzed to achieve the load-independent constant current (CC) and load-\nindependent constant voltage (CV) outputs. On this basis, multiple power levels can be achieved \nunder CC/CV conditions by bridge arm switching, which makes it possible to complete charging \ntasks for multiple power level electric vehicles (EV) without switching the IPT system. A circuit \nsimulation was built to verify the different power level switching effects of the structure. A 3.3 kW \nIPT system was designed to verify the proposed structure. At the rated output power, the \nexperimental efficiency was up to 92.04% and 91.21% in CC and CV output modes, respectively....
The wireless power transfer (WPT) technology has the advantages of convenience, safety\nand reliability due to its non-metal contact power supply and has a broad application prospect in\nmany occasions. In practical applications, the information communication between the primary and\nsecondary side is necessary for output voltage control, load detection, condition monitoring and\nother functions, which makes the WPT system more intelligent and convenient. A simultaneous\nwireless information and power transfer (SWIPT) system with controlled chopper circuit receiver is\nproposed in this paper. The load voltage remains constant by adjusting the pulse width of the\nsecondary controlled device through feedback control. The information bidirectional transmission\nmethods and two modes are proposed, considering different application scenarios. Simulation and\nexperiment results validate the proposed topology and the method of information bidirectional\ntransmission....
The design and implementation of an asymmetrical Doherty power amplifier are\ndiscussed, where two Cree GaN High Electron Mobility Transistors (HEMTs) devices are used for\ndesigning an asymmetrical Doherty power amplifier to achieve saturated power of 48 dBm and\noptimal back-off efficiency of 8 dB in the frequency band of 3.3-3.5 GHz. Rogers RO4350B material\nis used as a substrate material, a back-off of 8 dB was achieved with an average gain of 10 dB. Loadpull\ndata are an important tool for determining the optimum load impedance that the transistor\nneeds to see. Additionally, the measured efficiency was 50% when the designed amplifier was tested\nby a modulated signal of 8 dB peak-to-average-power ratio when the average output power was 40\ndBm. At the same time, the linearity of the designed amplifier was measured and found 31.8 dB\nwhich can be improved using a digital pre-distorter. The gain phase measurement can be used as\nan indicator for compensating the phase difference between the two cells....
The design and testing phase of photovoltaic (PV) power systems requires timeconsuming\nand expensive field-testing activities for the proper operational evaluation of maximum\npower point trackers (MPPT), battery chargers, DC/AC inverters. Instead, the use of a PV source\nemulator that accurately reproduces the electrical characteristic of a PV panel or array is highly\ndesirable for in-lab testing and rapid prototyping. In this paper, we present the development of a\nlow-cost microcontroller-based PV source emulator, which allows testing the static and dynamic\nperformance of PV systems considering different PV module types and variable operating and\nenvironmental conditions. The novelty of the simple design adopted resides in using a low-cost\ncurrent generator and a single MOSFET converter to reproduce, from a fixed current source, the\nexact amount of current predicted by the PV model for the actual load conditions. The I-V\ncharacteristic is calculated in real-time using a single diode exponential model under variable and\nuser-selectable operating conditions. The proposed method has the advantage of reducing noise\nfrom high-frequency switching, reducing or eliminating ripple and the demand for output filters,\nand it does not require expensive DC Power source, providing high accuracy results. The fast\nresponse of the system allows the testing of very fast MPPTs algorithms, thus overcoming the main\nlimitations of state-of-art PV source emulators that are unable to respond to the quick variation of\nthe load. Experimental results carried on a hardware prototype of the proposed PV source emulator\nare reported to validate the concept......................
In DC microgrid (DC-MG), the loads connected with converters under strict control are\nconsidered as CPLs (constant power loads). When the voltage of CPLs decreases, the current\nincreases and the negative impedance characteristic of CPLs cause instability easily. Fortunately,\nappropriate Control for energy storage units could improve the system stability. However, most\ntraditional control methods for bidirectional DC-DC power converters (BDC) connected with\nbattery storage units do not quantitatively consider the stability influences of control parameters.\nThis paper quantitatively analyzes the stability influence of the BDC current-mode control\nparameters and the negative impact of CPLs and derives the control parameter determination\nmethod for BDC interfaced storage systems. Large signal stability constraints are obtained in terms\nof mixed potential function. According to the constraints, the large signal stability is improved when\nthe BDC control parameter kp increases, while the stability is degraded when the power of CPLs\nincreases. The control parameter determination method is very effective and convenient to apply,\nand the appropriate parameter kp for BDC is determined. The regions of asymptotic stability (RAS)\nidentify that the proposed control parameter determination method could improve the system\nstability effectively. The determination method is fully verified by the simulation and experimental\nresults....
Loading....