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This paper studies on/off control of a dc-dc system that contains multiple active-clamp LLC resonant modules operating in parallel. The architecture and the on/off control method yield high overall efficiency and fast transient responses. Two converter models are introduced for different purposes: (1) a high-frequency model to determine a gate timing sequence that enables fast on/off control, and...
This paper derives the small-signal model and designs the controller for a high boost ratio dc-dc converter with the application for PV modules. A voltage controller with proportional-integral (PI) cascaded quasi-resonant (QR) controllers is presented for an inner PV voltage loop of maximum power point tracking (MPPT) control. Here, PI controller provides fast-tracking of voltage reference and maintains...
This paper proposes a novel current measurement method for Maximum Power Point Tracking (MPPT) control of thermoelectric power generation. This paper presents the possibility to use the MOS-FET as the current measuring resistance, instead of conventional measuring methods, such as the DC-CT or the shunt resistance. Former is high cost and latter causes energy loss. The reduction of components is also...
A common approach for selecting a suitable EMI filter is detailed based on the example of a realized single-phase 500W PFC rectifier. The presented work separates conducted EMI noise into Differential Mode (DM) and Common Mode (CM) components and derives expressions for the DMand CM insertion losses achieved if a given EMI filter is connected to a dedicated power converter. With the use of hardware...
A breadth of advanced manufacturing technologies utilize plasma based material processing. A central system to plasma processing schemes is the RF power delivery and associated components. In a conventional RF power delivery system, the RF power supply performs power regulation for a desired power leveling quantity, and an impedance tuning network operates autonomously to match the dynamic and nonlinear...
This paper studies the dynamic voltage stability of a typical aircraft power system - variable frequency generation system loaded with PWM rectifier as a constant power load. The L-CCR filter is used for reducing input current harmonics of the rectifier. It establishes the small-signal model of the system. The parameters dominating the system stability were studied based on the eigenvalues of the...
Differential power processing (DPP) architectures employ low power rated dc-dc converters to mitigate, without insertion losses, mismatches in series strings of photovoltaic (PV) cells. This paper presents tools for simulation of PV systems based on the isolated-port submodule integrated converter (subMIC) DPP architecture. While the ideal operation with full power rated subMICs is relatively easy...
In this paper a new control-interface card for developing simple control loops and generating test signals for power electronic converters is presented. The control board can operate with two computational cores (Texas Instruments and Microchip) allowing using the preferred DSP architecture and development environment. Moreover, the interface board can operate with open hardware Arduino-like boards...
This paper presents a simple and fast Maximum Power Point Taking (MPPT) for a grid connected photovoltaic (PV) system. The adopted MPPT technique is based on the determination of the optimum slope of the power load line. This method needs the measurement of short circuit current of the PV panel. The choice of the whole of the elements of the adopted (PV) system (CDC capacitor, L inductance, transformer...
In order to optimize the clamped inductive load (hard) switching behavior of IGBTs in voltage source power electronic converters, i.e. to ensure a defined switching behavior independent of the load current level, the DC-link voltage or the junction temperature, in recent publications an IGBT gate drive for controlling diC/dt and dvCE/dt has been proposed and experimentally verified for chopper circuits...
Hot spots result from localized heating in a string of photovoltaic (PV) cells due to mismatch that is often caused by partial shading or uneven degradation. Over time, this localized heating can result in permanent damage and degrade string performance. Bypass diodes are commonly employed in PV panels to mitigate this problem, but it does not eradicate the problem—hot spots can still form. This study...
Despite recent market conditions and significant consolidation among photovoltaic (PV) module and cell manufacturers, the widespread deployment of PV technologies is increasingly viable. Recent advances in power electronics systems include the emergence of sub-module partial-power processing architectures based on multi-level ladder converters. This work presents a control scheme and a multiple-input,...
This work demonstrates a method for rapid maximum power point tracking in photovoltaic applications using dithered PWM control. Constraints imposed by power consumption, cost and component size, limit the available PWM resolution of a power converter, and may in turn limit the MPP tracking efficiency of the PV system. PWM dithering can be used to improve average PWM resolution. However, additional...
This paper presents a comprehensive summary and detailed analysis on the modeling of modular multilevel converters for High Voltage Direct Current (HVDC) transmission, and develops a state-space switching model for the now well-known Modular Multilevel Converter (MMC), and also for the more recently developed Alternate Arm Converter (AAC). Various models used for the MMC are firstly discussed, followed...
High-voltage dc (HVDC) is an attractive alternative to conventional ac transmission for offshore wind farms as well as bulk power transmission application. This paper reviews different HVDC architectures and their control methods for systems based on both conventional line commutated converters (LCC) and new voltage-source converters (VSC). The reviewed system architectures include both point-to-point...
Recent PV faults and subsequent fire-hazards on April 5, 2009, in Bakersfield, California, and April 16, 2011, in Mount Holly, North Carolina provide evidence of a lack of knowledge among PV system manufacturers and installers about different PV faults. The conducted survey within the scope of this paper describes various faults in a PV plant, and explains the limitations of existing detection and...
This work investigates the stability and control of offshore wind farms with high-voltage dc (HVDC) connection to onshore power grids. An impedance-based stability criterion is applied to determine the stability of the offshore ac collection bus and to develop control requirements for the wind inverters as well as the HVDC rectifier built based on voltage-source converters (VSC). Positive- and negative-sequence...
The expansion of cities often leads to enlarged load concentration and carries extra challenges to managing the electrical grid while insuring power availability to critical loads. The developing Shanghai power grid faces many challenges in the areas of generation, transmission, and distribution of the rapidly growing amounts of electrical energy in demand. Its development should address issues of...
A compact Super-Junction MOSFET model is reported. The model describes all device performances based on the potential distribution calculated by solving the Poisson equation and the current continuity between channel and resistive drift region. The main focus is given on describing the resistance effect in the drift region, where the current flow is first parallel to the surface and then changes into...
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