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2549 results about "Sine wave" patented technology

A sine wave or sinusoid is a mathematical curve that describes a smooth periodic oscillation. A sine wave is a continuous wave. It is named after the function sine, of which it is the graph. It occurs often in pure and applied mathematics, as well as physics, engineering, signal processing and many other fields. Its most basic form as a function of time (t) is: y(t)=Asin(2πft+φ)=Asin(ωt+φ) where: A, amplitude, the peak deviation of the function from zero. f, ordinary frequency, the number of oscillations (cycles) that occur each second of time.

Low-Noise High Efficiency Bias Generation Circuits and Method

A bias generation method or apparatus defined by any one or any practical combination of numerous features that contribute to low noise and/or high efficiency biasing, including: having a charge pump control clock output with a waveform having limited harmonic content or distortion compared to a sine wave; having a ring oscillator to generating a charge pump clock that includes inverters current limited by cascode devices and achieves substantially rail-to-rail output amplitude; having a differential ring oscillator with optional startup and/or phase locking features to produce two phase outputs suitably matched and in adequate phase opposition; having a ring oscillator of less than five stages generating a charge pump clock; capacitively coupling the clock output(s) to some or all of the charge transfer capacitor switches; biasing an FET, which is capacitively coupled to a drive signal, to a bias voltage via an “active bias resistor” circuit that conducts between output terminals only during portions of a waveform appearing between the terminals, and/or wherein the bias voltage is generated by switching a small capacitance at cycles of said waveform. A charge pump for the bias generation may include a regulating feed back loop including an OTA that is also suitable for other uses, the OTA having a ratio-control input that controls a current mirror ratio in a differential amplifier over a continuous range, and optionally has differential outputs including an inverting output produced by a second differential amplifier that optionally includes a variable ratio current mirror controlled by the same ratio-control input. The ratio-control input may therefore control a common mode voltage of the differential outputs of the OTA. A control loop around the OTA may be configured to control the ratio of one or more variable ratio current mirrors, which may particularly control the output common mode voltage, and may control it such that the inverting output level tracks the non-inverting output level to cause the amplifier to function as a high-gain integrator.

Charging-discharging system for V2G bilateral power conversion electric automobile and control method thereof

The invention discloses a charging-discharging system for a V2G bilateral power conversion electric automobile and a control method thereof, which belong to the technical field of intelligent power grids. In the charging-discharging system, a single-phase or three-phase voltage PWM (Pulse Width Modulation) converter (VSC) is taken as a first-grade power conversion circuit, so that energy conversion between an alternating-current power grid and a first direct-current bus is realized; and a symmetric half-bridge LLC (Logical Link Control) resonant bilateral direct current-direct current (DC/DC) converter is taken as a second-grade power conversion circuit, so that energy conversion between a direct-current bus and a power battery pack is realized. The charging-discharging system has the beneficial effects that: the current of the converter power grid side of the first-grade power conversion circuit is approximate to sine wave, so that the harmonic content is small; and the converting efficiency, dynamic performance and power density of the second-grade power conversion circuit are increased, the volume and weight of a charging-discharging device of the electric automobile are reduced, and the safety, reliability and economic efficiency of the system are improved effectively.

Square wave three-phase brushless permanent magnetic DC motor

The invention relates to a square wave three phase brushless permanent magnet dc motor. In order to solve the problems existed in the prior square wave permanent magnet motor and sine wave permanent magnet motor, a magnetic pole number 2P is equal to 8 on a rotor iron core; a slot number Z is equal to 12 of a stator iron core, twelve teeth comprises three big teeth, three middle teeth and six small teeth;a mechanical angle ratio of the big teeth is 50 degree +/- 5 degree, the mechanical angle ratio of the middle teeth is 40 degree +/- 5 degree,the mechanical angle ratio of the small teeth is 15 degree +/- 5 degree,and a total mechanical angle ratio of one big tooth plus one middle tooth plus two small teeth is equal to 120 degree.The three phase concentrated windings respectively wind on the big teeth and middle teeth, each phase only has two concentrated windings and the three phase motor only has six concentrated windings. The motor can generate a stable torque when driven by a three phase square wave current and a torque fluctuation index is equivalent to that of the sine wave permanent magnet. The motor of the invention has a series of advantages of minimum winding end, minimum air gap, minimum material, minimum locating torque and minimum loss or the like.

Method and apparatus for controlling power factor correction

In a method and apparatus for controlling power factor correction (PFC) in mixed operation modes, a frequency of the input voltage is obtained by detecting the zero crossing points of the input voltage. A peak of the input voltage is obtained by detecting input voltage with 90 degree phase. Thus, the present invention predicts the input voltage by its frequency and peak and the characteristic of the sine wave. A digital signal processor computes the duty and frequency of a boost switch, switching the operation mode of the boost converter among continuous mode, critical mode and discontinuous mode according to input voltage or the load. According to another aspect, the operation is switched to critical mode from the average current mode when a zero current is detected before the charging and recharging cycle of the boost switch is finished. Overcurrent protection may be achieved by controlling current in response to detected voltage to provide a substantially constant power level. The overcurrent protection may be adaptive in nature. In this aspect, an adaptive driver for a PFC controller reduces the slew rate of signals over the boost switch of the PFC controller. The adaptive driver may have a group of transistors which may be divided into a plurality of branches. The charging current through the boost switch may be increased by turning on an increasing number of branches until the voltage over the switch exceeds a reference voltage, and this may determine the number of branches to drive the boost switch during normal operation.
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