BSH Home Appliances (United States)

For the first time, die-level electrical stress from current crowding is analyzed by InfraRed (IR) thermography in an IGBT operating in a half-bridge resonant converter outside the zero-voltage switching (ZVS) regime from 150 to 75 kHz. Custom IR image processing with Fourier coefficients and time reconstruction enables non-invasive 10 μm, sub-millisecond monitoring of the device's surface thermal map during switching operation, identifying overheated areas in low-impedance regions at a tens of microseconds time scale.

Abstract With the enhancement of people's awareness of environmental protection and the improvement of environmental quality requirements, it is necessary to evaluate the effect of kitchen smoke exhaust on the environment. We introduced the structural definition of the parameters involved in the centralized exhaust flue and the range hood model in the centralized flue exhaust system. The iterative function calculation flow of the smoke output is clarified and the convergence of the iterative function was verified. To ensure the accuracy of parameters in the control equation which include the combined resistance coefficient of the pipeline's inner wall, we used CFD to solve resistance coefficients in the flue model of this smoke exhaust system. This solution was later verified experimentally. We deployed C# language for parametric programming, which allowed us to accommodate changes in different conditions. These include the number or height of layers, flue size, hood model, branch pipe length and type, valve angle, check valve type, and operating rate, among others. The results show that different pipe structures and smoke exhaust conditions are represented as a whole by parameters, which can be quickly calculated and displayed visually visualization program of flow changes in various layers inside the centralized exhaust flue. Lastly, we utilized the model to simulate a scenario, following which we evaluated the impact of the centralized exhaust flue in that scenario. The results of this study can guide the modeling of centralized flue systems and the evaluation of the effect of the exhaust pipe.

Three-phase inverters for grid-connected applications typically require some form of grid voltage phase detection in order to properly synchronize to the grid and control real and reactive power. This phase detection is usually based upon some type of grid voltage sensing. However, in this work, a method is proposed, whereby the phase angle of the grid can be accurately identified solely via the grid current feedback. In the proposed current-control scheme, the only measurement is the output inverter current, and no phase-locked loop (PLL) exists within the scheme. This phase observer is incorporated into a current controller, which can manage the injected power to the grid. The design of this combined observer/controller system is motivated and validated via a Lyapunov stability analysis. The performance of the proposed control scheme has been compared with the conventional PI PLL-based control scheme that needs both a grid voltage and a current sensors. Experimental results utilizing a Controller+ Hardware-in-the-Loop test bed have been presented in order to validate the proposed observer/controller scheme under normal operation, weak grid, distorted grid, and faulty grid conditions. To summarize, this scheme archives current control for a grid-connected inverter using only current feedback. In comparison, traditional methods require voltage and current feedback along with a PLL to synchronize with the grid creating a cascaded closed-loop control system.

PCB technology provides an alternative to conventional Wireless Power Transfer (WPT) coils made of wound copper wire. The most common wires for conventional coils are either a single wire or a multistranded cable conforming a litz wire structure. On the other hand, the implementation on printed board is suitable for medium-low power applications, presenting advantages as low cost, high repetibility and compact design. Moreover, for reduced losses, the litz wire structure can be adapted to a PCB implementation. In this paper, a mathematical description of the PCB litz structure is presented together with a method to automatically generate PCB layouts of custom coils. Following this method, several prototypes were built and tested. The experimental characterization of the samples shows that coils with PCB litz structure present reduced losses.

While there have been extensive studies on thermofluid characteristics of different magnetocaloric refrigeration systems, a conclusive optimization study using non-dimensional parameters which can be applied to a generic system has not been reported yet. In this study, a numerical model has been developed for optimization of active magnetic refrigerator (AMR). This model is computationally efficient and robust, making it appropriate for running the thousands of simulations required for parametric study and optimization. The governing equations have been non-dimensionalized and numerically solved using finite difference method. A parametric study on a wide range of non-dimensional numbers has been performed. While the goal of AMR systems is to improve the performance of competitive parameters including COP, cooling capacity and temperature span, new parameters called “AMR performance index-1” have been introduced in order to perform multi objective optimization and simultaneously exploit all these parameters. The multi-objective optimization is carried out for a wide range of the non-dimensional parameters. The results of this study will provide general guidelines for designing high performance AMR systems.

Domestic induction cookers can have several heating areas, hence multiple‐output topologies are commonly used. One of these multiple‐output topologies is the double series‐resonant half‐bridge inverter. An upgrading of this topology is proposed. This upgrading consists of adding a relay to allow connecting the capacitor tanks in parallel. The aim of this upgrading is to increase the efficiency through the reduction of the device currents. The proposed upgrading topology has been tested by means of a prototype.

This paper presents a real-time algorithm to predict the energy consumption of the heating, ventilation, and air conditioning (HVAC) system at home. The autoregressive model with exogenous inputs (ARX model) is used to identify the house thermal model. The ARX model, with the thermostat controller, is simulated to obtain the future state of the HVAC system with the knowledge of the weather forecast data obtained from a weather server. The utility bill for the HVAC system can be estimated if a real-time price model is provided, thereafter. The proposed method is validated by experimentation in a particular home using GE Nucleus energy management system for data aggregation and algorithm implementation. The experimental results show that the energy prediction error is around 15% in both heating and cooling mode of the HVAC system.

New mathematical models of L-Complementary self-oscillating class D inverter with output voltage clamping in the steady state and during starting are proposed in this paper. The proposed models are very useful for predicting the converter operation and optimizing the circuit design. Experimental results for 42watt spiral CFL electronic ballast are presented to validate the analysis.