ON Semiconductor (Czechia)

This letter describes a new average current control dc–dc LED driver suitable for automotive pixel (matrix) lighting. Current is sensed only on an integrated high side switch and peak current is controlled to achieve required average output current independent of tolerances of components and parameters other than the current sensing itself. Fast reaction to output voltage changes required by the pixel light operation is achieved by using a constant ripple control with an off time inversely proportional to the output voltage.

In this work two different methods for the identification of the cogging torque in three-phase Permanent Magnet (PM) motors are presented. The cogging torque map carried out from these methods is then used in a Field Oriented Control (FOC) algorithm to mitigate the ripple in speed and torque. The first method uses a high bandwidth position control loop in a FOC structure, in which a slow and accurate positioning of the rotor is implemented and the cogging torque map is extracted from the q-axis current. Second method uses Load Torque Observer (LTO), which is able to observe various disturbances like load, friction but also the cogging torque. These two methods are experimentally verified and compared. After having identified the most significant harmonics in the cogging torque waveform, they have been suitably added to the q-axis current reference of a FOC in order to mitigate the ripple in torque and speed caused by cogging torque. The effectiveness of the cogging torque reduction algorithm was experimentally verified by significant minimization of the speed ripple.

Field-oriented control of PMSM motors without a position or speed sensor is very popular mainly in automotive industry. Many self-sensing/sensorless techniques have been introduced, including saliency-based (high-frequency signal injection) or model-based techniques. This paper focuses on the model-based techniques applications, where an open-loop start-up sequence has to be used. I-F open-loop start-up techniques are discussed. Simulation model and experiments are introduced to explain the open-loop start-up situation in more details. Novel simple current cross-over technique is introduced and tested in concept, indicating positive impact on the start-up reliability especially for low-load or no-load start-up conditions, thus e.g. cooling fan or blower applications.

The main aim of this paper is to design such synchronous reluctance rotor, whose parameters are comparable with induction motor (IM) and with existing original reluctance synchronous rotor with the same stator. This paper deals with Finite Element Analysis (FEA) and experimental methods used for new developed and designed reluctance synchronous rotor parameters investigation. The investigated equivalent circuit parameters are synchronous and magnetizing inductances in d and q axis, rotor parameters and developed electromagnetic torque. These parameters are calculated by means of FEM and verified by measurements. The output torque and power are compared with original reluctance synchronous motor (RSM) and with IM at the same phase current.

The future space X-ray astronomy imaging missions require very large collecting areas at still fine angular resolution and reasonable weight. The novel space Xray optics substrates such as Silicon wafers and thin thermally formed glass enable wide applications of precise and very light weight (volume densities 2.3 to 2.5 gcm-3) optics. The recent status of novel technologies as well as developed test samples with emphasis on precise optical surfaces based on novel materials and their space applications will be presented and discussed.

The future space X-ray astronomy imaging missions require very large collecting areas at still fine angular resolution and reasonable weight. The novel substrates for X-ray mirrors such as Silicon wafers and thin thermally formed glass enable wide applications of precise and very light weight (volume densities 2.3 to 2.5 gcm-3) optics. The recent status of novel technologies as well as developed test samples with emphasis on precise optical surfaces based on novel materials and their space applications is presented and discussed.

In this work, a high voltage (HV) galvanically isolated chip-to-chip communication circuit utilizing laterally coupled resonators is reported. The adjacently placed resonators provide high voltage galvanic isolation (GI) using horizontal space between resonators filled with oxide, which minimizes the need for thick inter-metal dielectrics. A previously unexplored application for lateral coupling is introduced as a passive communication channel for GIs. Magnetic coupling between resonators is used to transfer an upconverted digitally-modulated OOK control signal at 2.8 GHz through the galvanic isolator. This proposed method can be integrated using CMOS processes, without altering the native process or adding extra fabrication steps. The system is realized in a 0.25 µm BCD (Bipolar-CMOS-DMOS) process with only four metal layers for proof of concept. The design does not require exotic packaging and provides 3.3kV RMS isolation, small physical area of 0.95mm2, and sub-20ns propagation delay. The implemented resonators inherently act as bandpass filters, thus enhancing circuit noise immunity to common mode transients.

This paper presents a resistance model of integrated octagonal-shaped Hall sensor device. The nonlinear voltage dependent, temperature and parasitic junction (leakage & capacitance) effects are modeled using JFET compact model. The model topology consists of eight nonlinear resistor models with two types of resistance. This approach reduces the number of model parameters with sustaining high model accuracy and reduces the modeling time significantly. The JFET compact model is available in many commercial SPICE simulators, e.g. Eldo, Spectre or Hspice.