Scholarly Works, Electrical and Computer Engineering
Permanent URI for this collection
Research articles, presentations, and other scholarship
Browse
Browsing Scholarly Works, Electrical and Computer Engineering by Content Type "Patent"
Now showing 1 - 20 of 68
Results Per Page
Sort Options
- Anti-islanding detection for three-phase distributed generation(United States Patent and Trademark Office, 2017-04-25)Wobbling the operating frequency of a phase-locked loop (PLL), preferably by adding a periodic variation is feedback gain or delay in reference signal phase allows the avoidance of any non-detection zone that might occur due to exact synchronization of the phase locked loop operating frequency with a reference signal. If the change in PLL operating frequency is periodic, it can be made of adequate speed variation to accommodate and time requirement for islanding detection or the like when a reference signal being tracked by the PLL is lost. Such wobbling of the PLL operating frequency is preferably achieved by addition a periodic variable gain in a feedback loop and/or adding a periodically varying phase delay in a reference signal and/or PLL output.
- Apparatus and Method for Induction HeatingLai, Jih (2004-04-27)
- Avoiding internal switching loss in soft switching cascode structure device(United States Patent and Trademark Office, 2017-08-15)In a cascode switching device, avalanche breakdown of a control transistor and loss of soft switching or zero voltage switching in a high voltage normally-on depletion mode transistor having a negative switching threshold voltage and the corresponding losses are avoided by providing additional capacitance in parallel with a parallel connection of drain-source parasitic capacitance of the control transistor and gate-source parasitic capacitance of the high voltage, normally-on transistor to form a capacitive voltage divider with the drain-source parasitic capacitance of the high voltage, normally-on transistor such that the avalanche breakdown voltage of the control transistor cannot be reached. The increased capacitance also assures that the drain source parasitic capacitance of the high voltage, normally-on transistor is fully discharged before internal turn-on can occur.
- Circuit and method for driving synchronous rectifiers for high-frequency flyback converters(United States Patent and Trademark Office, 2017-11-07)A voltage waveform similar to a waveform of a magnetizing current of an isolation transformer and immune to high frequency oscillatory resonant behavior is developed across a capacitor of a series resistor and capacitor connection connected in parallel with a synchronous rectifier. A simple logic circuit produces a waveform for controlling the synchronous rectifier which is not subject to significant turn on delay or early turn off caused by oscillatory resonances among parasitic inductances and capacitances. Improved timing accuracy of a synchronous converter provides improved power converter accuracy, particularly for flyback converters which are commonly used in converters for supplying power to offline electrical devices but are subject to oscillatory resonant behaviors that cannot be adequately damped at switching frequencies sufficiently high to support miniaturization of adapters.
- Cognitive reconfigurable RF technology(United States Patent and Trademark Office, 2017-11-21)The present invention provides a radio architecture that contains a main radio path and a sensing path. The parameters of the main radio path are controlled by a cognitive engine. The main radio path is tuned to a desired frequency band. The sensing path is used to monitor the spectrum around the desired frequency band. To minimize effects of undesired non-linearity on sensing, sensing path may have a lower gain setting. The cognitive engine determines the optimal setting of the main RF front-end with respect to the current state of the spectrum.
- Cooperative modulation of classification in cognitive radio networks(United States Patent and Trademark Office, 2016-11-22)Multiuser classification of the modulation schemes of simultaneous multiple unknown transmitters is disclosed. Cooperation among multiple cognitive radio receivers for modulation classification offers improvements in classification performance and overcomes detrimental channel effects that degrade single cognitive radio classifier performance. A centralized soft-combining data fusion algorithm based on the joint probability distribution of fourth order cumulants is presented for cooperative modulation classification. Fourth order cumulants of received signals are calculated as discriminating features for different modulation schemes at each cognitive radio node and sent to a centralized data node. The data node chooses the modulation scheme that maximizes the joint probability of the estimated cumulants.
- DC-DC power conversion apparatus and methodLai, Jih (2016-05-31)
- Delta connected resonant snubber circuitLai, Jih (1998-01-20)
- Electrical SystemLai, Jih (2020-09-30)
- Energy storage for power factor correction in battery charger for electric-powered vehicles(United States Patent and Trademark Office, 2018-03-13)Switches of a switching circuit used to control operation of an electric motor such as in an electrically powered vehicle connect respective windings of the electric motor as a single phase inductor during battery charging. The inductor can then store inherent low frequency, second order ripple power and return that power to a load presented by a battery during battery charging to deliver substantially constant current. Storage of ripple power in the inductor allows the capacitance value, size, weight and cost of a filter capacitor of a power factor correction circuit providing input power to a battery charger to be reduced by an order of magnitude or more. Direction of current flow through the inductor is periodically reversed to avoid magnetizing the motor.
- Estimating the location of a wireless terminal based on radio-frequency pattern matching and cooperative measurements(United States Patent and Trademark Office, 2017-03-14)A method for estimating the location of a wireless terminal is disclosed that is based on using: the known location of one or more devices, empirical data that indicates the relative position of the wireless terminal to the devices, and empirical data that indicates the relative position of the wireless terminal (which is at an unknown location) relative to other wireless terminals that are also at unknown locations.
- External ramp autotuning for current mode control of switching converter(United States Patent and Trademark Office, 2017-06-13)Peak current, valley current or average current mode controlled power converters in either digital or analog implementations obtain a stabilized feedback loop and allow high system bandwidth design by use of an external ramp generator using a slope computation equation or design parameters based on fixing the quality factor of a double pole at one-half of the switching frequency at a desired value The slope of the external ramp waveform is tuned automatically with knowledge of the slope change in the waveform of inductor current of a power converter derived by differentiating a waveform in the current feedback loop. This autotuning of the external ramp generator provides immunity of quality factor change under variations of duty cycle, component values of topological change of the power converter.
- High frequency integrated point-of-load power converter with embedded inductor substrate(United States Patent and Trademark Office, 2017-02-07)A low profile power converter structure is provide wherein volume is reduced and power density is increased to approach 1 KW/in3 by at least one of forming an inductor as a body of magnetic material embedded in a substrate formed by a plurality of printed circuit board (PCB) lamina and forming inductor windings of PCB cladding and vias which may be of any desired number of turns and may include inversely coupled windings and which provide a lateral flux path, forming the body of magnetic material from high aspect ratio flakes of magnetic material which are aligned with the inductor magnetic field in an insulating organic binder and hot-pressed and providing a four-layer architecture comprising two layers of PCB lamina including the embedded body of magnetic material, a shield layer and an additional layer of PCB lamina, including cladding for supporting and connecting a switching circuit, a capacitor and the inductor.
- High frequency quasi-resonant DC voltage notching scheme of a PWM voltage fed inverter for AC motor drivesLai, Jih; Bose, Bimal (1992-05-05)
- Hybrid interleaving structure with adaptive phase locked loop for variable frequency controlled switching converter(United States Patent and Trademark Office, 2018-07-03)In a multi-phase power converter using a phase-locked loop (PLL) arrangement for interleaving of pulse frequency modulated (PFM) pulses of the respective phases, improved transient response, improved stability of high bandwidth output voltage feedback loop, guaranteed stability of the PLL loop and avoidance of jittering and phase cancellation issues are achieved by anchoring the bandwidth at the frequency of peak phase margin. This methodology is applicable to multi-phase power conveners of any number of phases and any known or foreseeable topology for individual phases and is not only applicable to power converters operating under constant on-time control, but is extendable to ramp pulse modulation (RPM) control and hysteresis control. Interleaving of pulses from all phases is simplified through use of phase managers with a reduced number of PLLS using hybrid interleaving arrangements that do not exhibit jittering even when ripple is completely canceled.
- Iaverage current mode (ACM) control for switching power converters(United States Patent and Trademark Office, 2016-05-17)Providing a fast current sensor direct feedback path to a modulator for controlling switching of a switched power converter in addition to an integrating feedback path which monitors average current for control of a modulator provides fast dynamic response consistent with system stability and average current mode control. Feedback of output voltage for voltage regulation can be combined with current information in the integrating feedback path to limit bandwidth of the voltage feedback signal.
- Interleaved Multi-Channel Multi-level Multi-Quadrant DC-DC ConvertersBurgos, Rolando; Du, Yu; Aeloiza, Eddy (2021-04-13)Direct-current-to-direct-current (DC-DC) power converters that include two or more multi-quadrant, multi-level, DCDC, switching converter subcircuits, connected in parallel at respective input and output sides, so as to provide a multichannel, multi-quadrant, multi-level configuration, are disclosed. The DC-DC power converters further include a control circuit configured to control the switching converter subcircuits so that corresponding switching semiconductors in each of the switching converter subcircuits are switched in an interleaved manner. In some embodiments, each of the switching converter subcircuits is a three-level, neutralpoint- clamped, four-quadrant DC-DC converter circuit. In other embodiments, each of the switching converter subcircuits is a three-level, neutral-point-clamped, two-quadrant DC-DC converter circuit. In any of these embodiments, a filter capacitor may be connected between across a pair of output terminals at the output sides of the switching converter subcircuits.
- Line frequency commutated voltage source converters for multiphase modular multilevel converters(2022-11-29)Aspects are described for line frequency commutated voltage source converters for multiphase modular multilevel converters. A voltage source converter (VSC) capacitor voltage of a multiphase VSC of a multiphase power converter can be identified. The multiphase VSC can include a half-bridge circuit for each phase of the multiphase power converter. A circuit parameter can be identified and utilized to determine an arm voltage of an arm of a branch of the multiphase converter. Switch control signals can be generated to insert or bypass the VSC capacitor for the arm of the branch of the multiphase converter device, based at least in part on a comparison between the arm voltage and the VSC capacitor voltage.
- Low profile coupled inductor substrate with transient speed improvement(United States Patent and Trademark Office, 2018-10-23)A low profile inductor structure suitable for use in a high power density power converter has one or more windings formed by vias through a thin, generally planar body of magnetic material forming the inductor core and conductive cladding on the body of magnetic material or material covering the magnetic material body. Variation of inductance with load current and other operational or environmental parameters is reduced to any desired degree by forming a slot that removes all or a portion of the magnetic material between the locations of the vias.