Abstract: This invention relates to an apparatus and method for deriving speed and position information for an electric motor. Apparatus for and a method of controlling a motor 100 are also disclosed. The apparatus for providing information relating to the operation of an electrical motor 100 comprises a sampler 50, 51 for sampling the instantaneous motor current is and a processor 160 for determining the instantaneous rate of change of the motor current and providing information about the motion or position of said motor based on said instantaneous rate of change of the motor current. In this way speed and position information can be provided, at low speeds, and without using a speed sensor.

Abstract: Optimal operating techniques are disclosed for using coreless printed-circuit-board (PCB) transformers under (1) minimum input power conditions and (2) maximum energy efficiency conditions. The coreless PCB transformers should be operated at or near the ‘maximum impedance frequency’ (MIF) in order to reduce input power requirement. For maximum energy efficiency, the transformers should be at or near the “maximum efficiency frequency” (MEF) which is below the MIF. The operating principle has been confirmed by measurement and simulation. The proposed operating techniques can be applied to coreless PCB transformers in many circuits that have to meet stringent height requirements, for example to isolate the gates of power MOSFET and IGBT devices from the input power supply.

Abstract: A planar transformer structure, which can be constructed in an integrated semiconductor circuit without using traditional metallic windings. To avoid large thermal expansion of metallic spiral windings and associated mechanical stress on a metal-semiconductor interface, it is suggested that highly doped semiconductor materials with or without silicides and salicides can be used to form windings or conducting paths because their thermal expansion coefficients are similar to that of semiconductor material. The planar semiconductor transformer may find application for low-power and signal transfer that needs electrical isolation.

Abstract: There is provided a method that can detect the lamp type of fluorescent lamps and operate the lamp at the appropriate lamp power. The proposed method involves the classification of lamp characteristics of existing fluorescent lamps and the use of logic detection method such as a fuzzy logic detection and control technique to zoom into the right type of lamp. The information used in the lamp detection includes (1) lamp filament/electrode resistance, (2) lamp voltage and (3) lamp current. These three pieces of information can be used to select the appropriate fluorescent lamp type so that the control gear can operate the lamp at the right rated power. The importance of this invention can lead to a universal electronic ballast that can detect and operate all fluorescent lamps commonly available. It can also be used in a limited capacity to control a limited range of lamps.

Abstract: There is provided a planar inductive battery charging system designed to enable electronic devices to be recharged. The system includes a planar charging module having a charging surface on which a device to be recharged is placed. Within the charging module and parallel to the charging surface is at least one and preferably an array of primary windings that couple energy inductively to a secondary winding formed in the device to be recharged. The invention also provides secondary modules that allow the system to be used with conventional electronic devices not formed with secondary windings.

Abstract: The present invention provides an electronic ballast for a high intensity discharge lamp such as a metal halide lamp. The ballast includes an inverter and a resonant circuit with an ignition capacitor between the resonant circuit and the lamp. The ignition capacitor serves to provide the necessary start-up energy and also serves to provide a low impedance discharge path. A single ignition capacitor may be sufficient, but if a long cable is used to connect the lamp to the ballast, then two ignition capacitors in parallel at opposite ends of the cable may be used. The ballast further provides means for monitoring and controlling lamp power by monitoring a nominally constant dc link voltage, and means for detecting short-circuit and open circuit conditions. A retrial mechanism is provided in the event of the lamp failing to ignite that includes a temporary disabling of the inverter in order to keep the rms lamp voltage low.

Abstract: A battery charging apparatus comprises an inductive charging platform including a charging surface on which an electrical device to be charged is to be placed, and a first winding for generating lines of magnetic flux generally perpendicular to the charging surface. To compensate for voltage sag caused by a reduction in the flux generated by the first winding, a second winding is located within an area defined by the first winding for generating an auxiliary magnetic flux generally perpendicular to the charging surface.

Abstract: Dimming of an electrical lamp of the type driven by a ballast is provided by a reactive power device in series between the AC supply and the ballast. The reactive power device provides a variable auxiliary voltage out of phase by 90 or 270 degrees with the current such that a smaller magnitude voltage is applied to the lamp. The dimming device has a switch to enable/disable dimming. When the switch is enabled, the voltage applied to the lamp is controlled by a half-bridge inverter with a pair of totem pole power electronic switches, along with a pair of DC series capacitors and a low-pass filter.

Abstract: There is provided a planar inductive battery charging system designed to enable electronic devices to be recharged. The system includes a planar charging module having a charging surface on which a device to be recharged is placed. Within the charging module and parallel to the charging surface is at least one and preferably an array of primary windings that couple energy inductively to a secondary winding formed in the device to be recharged. The invention also provides secondary modules that allow the system to be used with conventional electronic devices not formed with secondary windings.

Abstract: The present invention provides an electronic ballast for a high intensity discharge lamp such as a metal halide lamp. The ballast includes an inverter and a resonant circuit with an ignition capacitor between the resonant circuit and the lamp. The ignition capacitor serves to provide the necessary start-up energy and also serves to provide a low impedance discharge path. A single ignition capacitor may be sufficient, but if a long cable is used to connect the lamp to the ballast, then two ignition capacitors in parallel at opposite ends of the cable may be used. The ballast further provides means for monitoring and controlling lamp power by monitoring a nominally constant dc link voltage, and means for detecting short-circuit and open circuit conditions. A retrial mechanism is provided in the event of the lamp failing to ignite that includes a temporary disabling of the inverter in order to keep the rms lamp voltage low.

Abstract: This invention relates to new soft-switching techniques for minimizing switching losses and stress in power electronic circuits using inverter legs. By choosing the switching frequency with specific relationships with the resonant frequency of the power electronic circuits, the proposed switching technique enables the power electronic circuits to achieve soft switching under full load and short-circuit conditions at the defined frequencies for both capacitive and inductive loads. This technique can be applied to an electronic circuit with two switches connected in totem pole configuration between two dc voltage rails or commonly known as a power inverter leg or inverter arm. Examples of these circuits are class-D power converter, half-bridge power converters and full-bridge power converters or inverters. The proposed techniques allow inverter circuits with resistive, capacitive and inductive loads to achieve soft switching.

Abstract: This invention relates to new soft-switching techniques for minimizing switching losses and stress in power electronic circuits using inverter legs. By choosing the switching frequency with specific relationships with the resonant frequency of the power electronic circuits, the proposed switching technique enables the power electronic circuits to achieve soft switching under full load and short-circuit conditions at the defined frequencies for both capacitive and inductive loads. This technique can be applied to an electronic circuit with two switches connected in totem pole configuration between two dc voltage rails or commonly known as a power inverter leg or inverter arm. Examples of these circuits are class-D power converter, half-bridge power converters and full-bridge power converters or inverters. The proposed techniques allow inverter circuits with resistive, capacitive and inductive loads to achieve soft switching.

Abstract: The present invention provides a low-cost and simple system for the remote control of dimmable electronic ballasts. The system includes a transmitter module for transmitting dimming data to a ballast, and a receiver module for receiving the dimming data and outputting a dimming signal in response thereto. Optionally the transmitter module may also control ON/OFF operation and will also include address data identifying the ballast to be controlled.

Abstract: An apparatus and method for determining the characteristic(s) of a discharge lamp (for example a fluorescent lamp or a high-intensity discharge lamp) operated by a high-frequency electronic ballast including a resonant tank that includes an inductor and a capacitor, wherein the characteristic(s) are selected from the group consisting of lamp input voltage, lamp resistance and lamp power, and including capability for measuring the inductor voltage and/or current, and capability for determining the characteristic(s) from the measured inductor voltage and/or current. More generally, the apparatus and method provide techniques for determining a number of parameters of a power converter circuit simply from measuring an inductor voltage or inductor current.

Abstract: The invention provides an apparatus and a method for controlling the power output of a fluorescent lamp in order to provide dimming control. The fluorescent lamp is driven by an electronic ballast, for example a half-bridge resonant inverter, and the electronic ballast is switched at a constant frequency and with a constant duty-cycle, but with a variable DC voltage power input. Dimming control is provided by variation of the DC voltage power supply. The variable DC supply may be obtained from an AC source followed by a power factor corrected AC-DC variable converter, or a DC source followed by a variable DC—DC converter.

Abstract: The present invention provides an electronic ballast for a high intensity discharge lamp such as a metal halide lamp. The ballast includes an inverter and a resonant circuit with an ignition capacitor between the resonant circuit and the lamp. The ignition capacitor serves to provide the necessary start-up energy and also serves to provide a low impedance discharge path. A single ignition capacitor may be sufficient, but if a long cable is used to connect the lamp to the ballast, then two ignition capacitors in parallel at opposite ends of the cable may be used. The ballast further provides means for monitoring and controlling lamp power by monitoring a nominally constant dc link voltage, and means for detecting short-circuit and open circuit conditions. A retrial mechanism is provided in the event of the lamp failing to ignite that includes a temporary disabling of the inverter in order to keep the rms lamp voltage low.

Abstract: The present invention provides an apparatus and method for determining the characteristic(s) of a discharge lamp (f rto example a fluorescent lamp or a high-intensity discharge lamp) operated by a high-frequency electronic ballast including a resonant tank comprising an inductor and a capacitor, wherein said characteristic(s) are selected from the group consisting of lamp input voltage, lamp resistance and lamp power, comprising means for measuring the inductor voltage and/or current, and means for determining said characteristic(s) from the measured inductor voltage and/or current. More generally, the present invention provides techniques for determining a number of parameters of a power converter circuit simply from easuring an inductir voltage or inductor current.

Abstract: The invention provides an apparatus and a method for controlling the power output of a fluorescent lamp in order to provide dimming control. The fluorescent lamp is driven by an electronic ballast, for example a half-bridge resonant inverter, and the electronic ballast is switched at a constant frequency and with a constant duty-cycle, but with a variable DC voltage power input. Dimming control is provided by variation of the DC voltage power supply. The variable DC supply may be obtained from an AC source followed by a power factor corrected AC-DC variable converter, or a DC source followed by a variable DC-DC converter.

Abstract: A bidirectional switched-capacitor power converter has a first step-up mode and a second step-down mode. The converter includes a capacitor in which in both modes is charged during a first switch topology and then discharged during a second switch topology. Two converters operating out of phase may be disposed in parallel to enable continuous power conversion.