The present disclosure describes a methodology for wireless power transmission based on pocket-forming. This methodology may include one transmitter and at least one or more receivers, being the transmitter the source of energy and the receiver the device that is desired to charge or power. The transmitter may identify and locate the device to which the receiver is connected and thereafter aim pockets of energy to the device in order to power it. Pockets of energy may be generated through constructive and destructive interferences, which may create null-spaces and spots of pockets of energy ranged into one or more radii from transmitter. Such feature may enable wireless power transmission through a selective range, which may limit operation area of electronic devices and/or may avoid formation of pockets of energy near and/or over certain areas, objects and people.

Wireless power transmission with selective range

In a phase-leg configuration, the high-switching-speed performance of silicon carbide (SiC) devices is limited by the interaction between the upper and lower devices during the switching transient (crosstalk), leading to additional switching losses and overstress of the power devices. To utilize the full potential of fast SiC devices, this paper proposes two gate assist circuits to actively suppress crosstalk on the basis of the intrinsic properties of SiC power devices. One gate assist circuit employs an auxiliary transistor in series with a capacitor to mitigate crosstalk by gate loop impedance reduction. The other gate assist circuit consists of two auxiliary transistors with a diode to actively control the gate voltage for crosstalk elimination. Based on CREE CMF20120D SiC MOSFETs, the experimental results show that both active gate drivers are effective to suppress crosstalk, enabling turn-on switching losses reduction by up to 17%, and negative spurious gate voltage minimization without the penalty of decreasing the switching speed. Furthermore, both gate assist circuits, even without a negative isolated power supply, are more effective in improving the switching behavior of SiC devices in comparison to the conventional gate driver with a -2 V turn-off gate voltage. Accordingly, the proposed active gate assist circuits are simple, efficient, and cost-effective solutions for crosstalk suppression.

Active Gate Driver for Crosstalk Suppression of SiC Devices in a Phase-Leg Configuration

Configurations and methods of wireless power transmission for charging or powering one or more electronic devices inside a vehicle are disclosed. A transmitter capable of single or multiple pocket-forming may be connected to a car lighter, where this transmitter may include a circuitry module and an antenna array integrated within the transmitter, or operatively connected through a cable. This cable may allow the positioning of the antenna array in different locations inside the vehicle suitable for directing RF waves or pockets of energy towards one or more electronic devices. Transmitter's configuration can be accessed by one or more electronic devices through Bluetooth communication in order to set up charging or powering priorities.

Wireless charging and powering of electronic devices in a vehicle

The present disclosure may provide a wireless power system which may be used to provide wireless power transmission (WPT) while using suitable WPT techniques such as pocket-forming. Wireless power system may be used in a wireless powered house for providing power and charge to a plurality of mobile and non-mobile devices. Wireless powered house may include a single base station which may be connected to several transmitters. Base station may manage operation of every transmitter in an independently manner or may operate them as a single transmitter. Connection between base station and transmitters may be achieved through a plurality of techniques including wired connections and wireless connections.

Wireless powered house

Embodiments directed to providing health safety in a wireless power transmission systems are disclosed herein. One embodiment includes a processing apparatus with a processor; a data storage; and one or more wireless power transmitters each including at least two antennas. The one or more wireless power transmitters receive instructions from the processing apparatus that cause the transmitters to transmit RF waves that constructively interfere to provide wirelessly delivered power to one or more receivers. The processing apparatus receives and processes wireless power proscribing data for each respective receiver, respective wireless power proscribing data including at least one user-specified circumstance that a user inputs as to when a respective electronic device coupled with the respective receiver is in use; and the processing apparatus causes transmission of the RF waves by the transmitters in accordance with determining that the at least one user-specified circumstance is not present at the respective electronic device.

System and method for providing health safety in a wireless power transmission system

A transverse ultra-thin insulated gate bipolar transistor having current density includes: a P substrate, where the P substrate is provided with a buried oxide layer thereon, the buried oxide layer is provided with an N epitaxial layer thereon, the N epitaxial layer is provided with an N well region and P base region therein, the P base region is provided with a first P contact region and an N source region therein, the N well region is provided with an N buffer region therein, the N well region is provided with a field oxide layer thereon, the N buffer region is provided with a P drain region therein, the N epitaxial layer is provided therein with a P base region array including a P annular base region, the P base region array is located between the N well region and the P base region, the P annular base region is provided with a second P contact region and an N annular source region therein, and the second P contact region is located in the N annular source region. The present invention greatly increases current density of a transverse ultra-thin insulated gate bipolar transistor, thus significantly improving the performance of an intelligent power module.

Transverse ultra-thin insulated gate bipolar transistor having high current density

Primary-side regulation (PSR) flyback converter with a discontinuous conduction modulation (DCM) mode is widely used in small-power applications. To introduce higher output power, a continuous conduction modulation (CCM) mode is used in which an analog to digital converter of high cost is always required. In this paper, to reduce the cost, a novel digital peak current control method is proposed to realize constant output current control in both DCM mode and CCM mode. However, there exists a time length calculation error that cannot be avoided in the critical condition between DCM mode and CCM mode. The output current will be lower than the nominal output current. Thus, a hysteretic multimode control method with two pulse width modulation modes and two pulse frequency modulation modes is utilized to eliminate the time length calculation error. In the proposed control, only a low-speed digital to analog converter and three comparators are used, which greatly reduced the cost, and high accuracy of output current can be obtained. The proposed control scheme was then verified through a field-programmable gate array (FPGA)-controlled 3.76–15 V/3.76 A PSR flyback converter. In the prototype, the accuracy of the output current is within ±1.5% for the universal load range.

A Low-Cost Constant Current Control Method for DCM and CCM in Digitally Controlled Primary-Side Regulation Flyback Converter

Considering the main parasitic parameters in brushless DC (BLDC) motor's driving circuit of “three phase bridge” topology, the switching characteristics under high frequency and large current circumstances are analyzed. Firstly, the switching operation process of the BLDC motor's driving circuit is presented. In particular, the Cdv/dt induced effect which is caused by main parasitic parameters of the circuit is analyzed in detail. Secondly, an equivalent circuit of one bridge leg is presented in modeling, and then the analytical solutions of the circuit's differential equations are derived. Based on the model, the simulations are performed to study the Cdv/dt induced effect with different values of main parasitic parameters. Finally, several design optimizations of BLDC motor's driving circuit are presented, and a practical prototype is used to validate the proposed approach.

Analysis and design optimization of brushless DC motor's driving circuit considering the Cdv/dt induced effect

The accurate model of switched reluctance motor (SRM) is critical for performance prediction. However, due to the doubly salient structure, the flux linkage of SRM is a non-linear function with phase current and rotor position, which makes the determination of the characteristic of SRM very difficult. In this study, indirect measurement method is used to obtain the sample data and least square support vector machine (LSSVM) is used for the prediction of flux linkage. First, the basic principles of indirect measurement and the exact methods of realisation are presented. Second, the errors in the indirect measurements are analysed and post-processing is given to reduce them. Third, the entire static electromagnetic characteristics are obtained by the prediction of improved LSSVM. The results are compared with those of using artificial neural network and those of using less training data by LSSVM, which shows both strong learning ability and generalisation ability. Finally, a simulation model is built up using MATLAB/Simulink and the results are compared between simulation and measurement. The good agreement shows that the proposed model has good accuracy. In addition, the LSSVM does not need any prior knowledge which is much easier for modelling than the existing literatures.

Accurate model of switched reluctance motor based on indirect measurement method and least square support vector machine

In order to improve the dynamic responses of multimode controlled primary-side regulation flyback converter, a novel digital control method is proposed in this paper. A new DAC sampling method, which can capture the output voltage during dynamic transition, is introduced. Based on it, a dynamic module which can monitor the variation of the output voltage to improve the dynamic performance is proposed. In a 5-V/1-A primary-side regulation flyback converter, the maximum undershoot voltage and overshoot voltage of the proposed control scheme in this study are 0.472 and 0.192 V, respectively. They are much lower compared to 1.296 and 0.584 V in the traditional control scheme. The maximum undershoot and overshoot recovery times are reduced from 10.86 to 1.29 ms and 126.3 to 53.68 ms, respectively. The proposed control scheme was then verified by a FPGA controlled prototype.

Shen Xu

Papers

Transverse ultra-thin insulated gate bipolar transistor having high current density

A Low-Cost Constant Current Control Method for DCM and CCM in Digitally Controlled Primary-Side Regulation Flyback Converter

Analysis and design optimization of brushless DC motor's driving circuit considering the Cdv/dt induced effect

Accurate model of switched reluctance motor based on indirect measurement method and least square support vector machine

Novel Digital Control Method for Improving Dynamic Responses of Multimode Primary-Side Regulation Flyback Converter