523 results about "Chopper" patented technology

A relatively low frequency chopping operation is applied to a delta-sigma ADC to reduce DC offsets resulting from non-ideal component operation. Sequential chopping takes place outside a closed loop and may include an inverted polarity feedback for a part of the chopping period. Nested chopping involves chopping within the closed loop, and may include an inverted polarity feedback and a time shift. The feedback compensation for sequential and nested chopping permits the correct polarity feedback to be provided at the desired time in conjunction with sampling and quantization events. Integrating capacitor(s) may be swapped in relative polarity during nested chopping to preserve residual conversion information for the desired polarity. The ADC operation is non-temperature dependent and avoids modification to the useful signal, resulting in higher accuracy.

Choppers are provided respectively in the output stages of two diode bridges, and their output sides are connected in parallel to a smoothing capacitor. By controlling the operations of the two choppers, the currents which are allowed to be inputted to the diode bridges are made triangular waves of mutually opposite phases, or middle-phase waveforms of three phases.

The utility model provides a wind farm super capacitor energy storage type unified power quality conditioner which comprises a compensation transformer, a series connection compensator, a parallel connection compensator, a current limiting circuit, a super capacitor group, a bidirectional DC/DC chopper circuit, a signal acquisition conditioning circuit, a control circuit and a driving circuit. The conditioner has two control modes which are a power regulating mode and a low voltage ride through mode. In the power regulating mode, the wind power unit assembly output power quality can be improved, in the low voltage ride through mode, namely in a fault condition, the blower outlet voltage can be maintained and is not reduced, and the current influence on a blower system is avoided until the voltage is recovered and the low voltage ride through is realized. Electric energy generated by the blower in a fault stage can be stored in the super capacitor group, the energy is transmitted to the power grid after a power grid is recovered to a normal state, and the waste of the electric energy is avoided. The conditioner has versatility and can be applied to wind farms of various blower generations of a fixed speed induction generator (FSIG), a permanent magnet synchronous generator (PMSG) and a double-fed induction generator (DFIG).

The invention relates to a vehicle auxiliary converter, which comprises a line side filtrating part (3), a direct-current conversion part (14) and an alternating-current conversion part (21). A diode (6) in the line side filtrating part is connected with a collecting electrode of a line side power switching tube (7), an emitting electrode of the line side power switching tube (7) is connected with an anode of a filtrating capacitor (9) to form the anode of a direct-current bus, both ends of a soft starting resistance (8) are respectively connected with the collecting electrode of the line side power switching tube (7) and the emitting electrode of the line side power switching tube (7). Power switching tubes of DC/DC wave choppers (10, 15) operate in a soft switching state. A DC/DC wave chopper (10) of the direct-current conversion part and the alternating-current conversion part is a zero-voltage soft switching resonant converter. The adoption of a contactless power switching tube instead of a contactor reduces the noise of the switch; as the power switching tube operates in the soft switching state, the consumption of the switch is reduced, and the adoption of a high-frequency transformer to insulate results in light weight.

A chopper-direct-conversion (CDC) radio receiver includes a phase-alternating mixer receiving an antenna input signal and at least one local oscillator signal and generating a double sideband signal in a single mixing step. The phase-alternating mixer may be implemented by two parallel mixers each mixing the input signal with one of two local oscillator signals and an adder receiving and summing outputs from the two parallel mixers, by a track-and-hold circuit sampling the input signal based upon the local oscillator signal, or by a window averaging circuit averaging the input signal across a period of the local oscillator signal. The CDC architecture is suitable for fabrication on a single chip and offers solutions to virtually all problems found in conventional direct-conversion receivers.

In the fast chopper circuit and method of the switched reluctance motor drive system, the current sampling circuit (4) collects the instantaneous value of the phase winding current of the motor, and transmits it to the microprocessor (1) in real time, and the microprocessor (1) judges the motor Whether the instantaneous value of the phase winding current needs chopping, and output the pulse width modulation signal and the chopping signal according to the judgment result. Control signal to control its upper switch tube. After the microprocessor (1) makes an internal judgment, it outputs the pulse width modulation signal and the chopping signal to the two-input AND gate (2) through the pulse width modulation module (11) and the input and output module (12): if the current is higher than the chopping signal If the current is lower than the lower limit of chopping, the chopping signal is set high to turn on the upper tube of the power converter (3). Control signal; realize fast chopping control of the power converter.

The invention provides a two-stage inversion type micro-arc oxidation power supply, comprising a main circuit, a control system and a human-computer interaction device, wherein, the main circuit comprises a power supply switch, an input rectifying and filtering circuit, a power inverter circuit, a high frequency transformer, an output rectifying and filtering circuit and a chopper inverter circuit. The control system comprises a control transformer and a control circuit. The human-computer interaction device comprises a keyboard and a display. The control transformer and the input rectifying and filtering circuit are respectively connected with a power frequency AC network by the power supply switch. The chopper inverter circuit is connected with a load. The control circuit is respectively connected with the power inverter circuit, the chopper inverter circuit, the keyboard, the display and the output end of the output rectifying and filtering circuit. The two-stage inversion type micro-arc oxidation power supply is characterized by high control precision, rapid response speed and multiple outputs. Furthermore, the technique stability is good and the intelligent monitoring is adopted, therefore, high efficiency, high frequency and intelligence can be realized.

A method of controlling a direct current (“DC”) chopper controller having a switch and a storage choke in which the choke has a current dependent on the switching of the switch on and off includes the following. A current variable derived from one of the time averaged value of the current of the choke and the peak value of the current of the choke is determined. A switching frequency for synchronizing the turning on and off the switch is calculated as a function of the current variable and on whether the current variable exceeds a current threshold. The switching frequency is determined to be a predetermined low frequency if the switching frequency is lower than the low frequency and is determined to be a predetermined high frequency if the switching frequency is greater than the high frequency. The switch is switched on and off in accordance with the switching frequency.

A chopper-stabilized amplifier includes a main signal path having first and second chopping circuits at the inputs and outputs of a transconductance amplifier, and an auto-correction feedback loop. The feedback loop includes a transconductance amplifier connected to amplify the chopped output from the main signal path, a third chopping circuit which chops the amplified output, a filter which filters the chopped output to substantially reduce any offset voltage-induced AC component present in the signal being filtered, and a transconductance amplifier which receives the filtered output and produces an output which is coupled back into the main signal path. When properly arranged, the auto-correction feedback loop operates to suppress transconductance amplifier-related offset voltages and offset voltage-induced ripple that might otherwise be present in the amplifier's output.

The invention concerns an installation constituting a railway propulsion chain, characterized in that it comprises, sequentially arranged, in the power electrical circuit, between a power transformer powered by a catenary and an electric motor of said vehicle, said catenary being capable of supplying a plurality of voltages, alternating or direct, said electrical circuit comprising a plurality of contact switches for selecting a given catenary voltage, at least one of the following elements: a controlled rectifier bridge (A1, A2), preferably a single-phase bridge with forced switching; a substantially reactive input filter (A3), preferably comprising at least a capacitance and/or at least an induction coil; a braking chopper capable of including also a clipping function (B); a multiphase and multilevel static converter (C1, C2, C3), preferably three-phase; electronic components, preferably IGBT power semiconductors for each element, each element belonging to at least an elementary power arm of the modular circuit diagram.

The invention relates to a wide-input voltage range arc power-supply device. A wide-range commercial power voltage is divided into a low-voltage module voltage, a medium-voltage module voltage and a high-voltage module voltage after rectified, filtered and stabilized, the low-voltage module voltage is boosted and the high-voltage module voltage is bucked as well as the medium-voltage module voltage is directly connected by a booster chopper circuit and a cascade voltage-reducing chopper, and then the low-voltage module voltage, the medium-voltage module voltage and the high-voltage module voltage are inverted by one group of inverters for obtaining the single voltage value with the required frequency so as to be used by an inversion type electric welder, and the single voltage value can be connected with the single-phase/three-phase power supply voltage, thus the flexibility is stronger.

The invention relates to a low-common-mode-noise grid-connected inverter circuit and a reactive power control method. The low-common-mode-noise grid-connected inverter circuit comprises an enhanced voltage-reducing chopper circuit and a silicon controlled rectifier power frequency phase-changing circuit, wherein the enhanced voltage-reducing chopper circuit comprises a power switch tube modulated through sinusoidal pulse width modulation (SPWM), a double-follow-current diode, a power-factor control power switch tube, an inductor and a capacitor. The direct current electric energy is converted into sine semiwaves by adjusting the duty ratio of high-frequency switch tubes in the enhanced voltage-reducing chopper circuit. The power-factor can be adjusted by adjusting a conducting mode of the power-factor control power switch tube. The phase-changing circuit consisting of four low-frequency silicon controlled rectifiers performs phase changing on the direct current sine semiwave to obtain full sine waves and finishes inversion from the direct current to the sine alternating current. Compared with conventional full-bridge grid-connected inverter circuits, the low-common-mode-noise grid-connected inverter circuit is simple in structure, strong in overcurrent-resisting capacity, high in stability and inversion efficiency and low in cost, and the number of the high-frequency switch tubes is approximately decreased by one half. Due to the fact that a whole inversion loop is fully symmetrical in the switching and phase-changing process, the common-mode voltage produced by inverted alternating-current output is constant, the common-mode current is restrained, and electro-magnetic interference (EMI) is reduced.

The invention discloses an AC chopper-full bridge rectification AC-DC converter in the technical field of power electronic conversion, comprising: a step-down circuit and a rectifier circuit or an impedance conversion circuit connected in series in sequence, and the step-down circuit is converted by an AC chopper The high-voltage power-frequency AC voltage is transformed into a high-voltage and high-frequency pulsed AC voltage, and the low-voltage and high-frequency pulsed AC voltage is obtained through step-down transformer step-down; the rectification circuit or impedance transformation circuit rectifies the output low-voltage and high-frequency pulsed AC voltage to obtain a stable The DC output and linear input impedance are reflected to the high-voltage AC grid to obtain linear input impedance and unit input power factor. The invention realizes the conversion of high-voltage AC voltage to low-voltage DC voltage through a step-down circuit and a rectifier circuit, and has the advantages of fewer power devices, simple overall structure and more perfect overall performance.

A cascaded H-bridge (CHB) inverter for higher rated power conditioning systems which operates at medium voltages while providing high power quality and low dv/dt. By incorporating battery energy storage, the power conditioning system operates at night to provide power to a load or grid and stabilizes the system during sudden changes in climatic conditions. Various energy storage system (ESS) configurations such as AC side coupled ESS, dual active bridge based ESS, and chopper based ESS configurations for cascaded H-bridge inverters are described. A comparison of these configurations on the basis of cost, control complexity, controller hardware requirements was performed and the advantages of chopper based ESS configurations over other ESS configurations was demonstrated. A control algorithm for the chopper based configurations was developed to operate the system in standalone and grid-connected modes of operation.

A method and arrangement for determination of the sharpness of chopping blades of a field chopper during chopping includes the steps of measuring, at least at two points in time, a characteristic parameter of the operating oscillation of a component of the chopping unit. Each such measurement obtains the oscillation fractions of at least two frequency bands of the measured signal or its peak, with the ratio between the two measurements being evaluated to generate a signal, when a certain deviation is determined between the initial measurement and the current measurement, which is indicative of the need to sharpen the chopping blades and the counterblade. The sharpening process can then be automatically initiated.

The invention provides a dynamic two-way wireless charging system for an electric vehicle. The dynamic two-way wireless charging system includes a transmitting device and a receiving device, the transmitting device includes an alternating current power supply, a power supply PFC circuit, a bi-directional DC/DC circuit, a first bi-directional AC/DC circuit, a first resonant compensation module, a first coil and a first control module; the receiving device includes a second coil, a second resonant compensation module, a second bi-directional AC/DC circuit, a storage battery pack, a third bi-directional AC/DC circuit, an alternating current dynamo, a super-capacitor and a second control module; and when the power PFC circuit works in a rectification mode, the bi-directional DC/DC circuit works in a buck chopper mode, the first bi-directional AC/DC circuit works in an inversion mode, the second bi-directional AC/DC circuit works in the rectification mode and the third bi-directional AC/DCcircuit works in the rectification or inversion mode, the electric vehicle is in a dynamic charging mode, and otherwise, the electric vehicle is in a feed mode. According to the dynamic two-way wireless charging system for the electric vehicle, the functions of dynamic charging of the electric vehicle and dynamic feed to a power grid are achieved at the same time, stable operation of the power grid is maintained, and energy waste is reduced.

The invention discloses a bidirectional high-frequency isolation type DC/DC module for realizing bidirectional transmission of electric quantity. The bidirectional high-frequency isolation type DC/DCmodule is characterized by comprising: a three-level boosting and voltage reduction circuit; and two bidirectional LLC full-bridge resonance conversion circuits, wherein the two bidirectional LLC full-bridge resonance conversion circuits are respectively connected with the three-level boosting and voltage reduction circuit. The bidirectional high-frequency isolation type DC/DC module can be applied to a bidirectional high-frequency auxiliary conversion system to realize the bidirectional transmission of power between the traction intermediate DC bus and the auxiliary intermediate DC bus, thereby realizing the bidirectional transmission of electric quantity between a traction intermediate DC bus and an auxiliary intermediate DC bus, so that the bidirectional energy flow of the conversion system is realized, and the rail emergency traction demands are met. Specifically, the three-level boosting and voltage reduction circuit can also reduce the voltage and current stress of a chopper circuit while realizing bidirectional power transformation, and improve the working range of the circuit; and the bidirectional LLC full-bridge resonance conversion circuit can realize the electric isolation of the bidirectional power transformation and input/output, meanwhile all switching tubes thereof can realize zero-voltage turn-on when used as chopper tubes, and can achieve zero-current turn-offwhen used as rectifier tubes, thereby improving the transformation efficiency.

A reference signal generation unit 110a generates a reference signal VCA representing a limit indicator. Under the control of a PWM control unit 120a, a bridge rectification circuit 130a controls the current supplied to a coil 19a to the limit indicator, using a current chopper method. Therewith, the circuit 130a implements synchronous rectification where transistors 10 and 12 are brought into conduction when the current supply is stopped, forming a closed circuit with the coil 19a, and a regenerative current circulates in the closed circuit. During a time period when the reference signal is decreasing relatively rapidly, a SR prohibition unit 115a prohibits the transistor 10 or 12 from being brought into conduction when the current supply is stopped, and thereby the decay of regenerative current is accelerated.

The invention provides a high-performance digital self-calibration chopper precision amplifier which is low in cost and easy to implement and an implementation method. The amplifier mainly comprises a digital self-calibration loop and a chopper circuit. After the amplifier is energized, the amplifier is configured as a digital self-calibration state within a period of time, and the chopper circuit and an amplifier output circuit are switched off. The calibrated digital quantity is stored in a register, and input offset voltage of the amplifier is calibrated through a digital analog converter. After the digital self-calibration state is finished, a comparison output circuit is switched off, the amplifier is configured as a chopper magnifying state, and the chopper circuit and the amplifier output circuit work, so that the input offset voltage of the amplifier, temperature drift of the offset voltage and flicker noise are lowered.

The invention discloses a low-voltage ride-through power supply of a frequency converter. The low-voltage rid-through power supply comprises a power circuit and a control circuit, wherein the power circuit consists of a main switch circuit, a rectifying circuit, a pre-charging circuit, a boosting chopper circuit, a switching circuit and a bypass circuit; the control circuit consists of a sampling circuit, a controller, a drive circuit and a control circuit power supply; a direct current capacitor is charged through a pre-charging resistor YR1 when a breaker QF is switched on for electrification, and the pre-charging resistor YR1 is bypassed after the electrification is finished; through full bridge uncontrolled rectification, the filter capacitor is used for feeding direct current into a boosting circuit, the boosting circuit is formed by connecting three BOOST circuits with same parameters in parallel; switching tubes of the three circuits are in standby states in the low-voltage ride-through power supply in an interleaving modulation mode, the isolation of the low-voltage ride-through power supply is realized through a thyristor switch, and switching control is realized according to a designed control strategy.

The invention relates to a low-high voltage cascading fault ride-through control method for a double-fed wind generating set, and belongs to the technical field of wind power generation. The method comprises the steps: for at the special condition of the low-high voltage cascading failure of a power grid, detecting a power grid voltage in real time, and quickly and accurately obtaining the positive sequence vector per unit value of the power grid voltage through an SOGI phase-locked loop, and quickly judging the low-high voltage cascading failure by combining a low-voltage penetration end marksignal; when a power grid has a low-high voltage cascading failure, performing the coordination control of cooperation and combined action of a grid-side converter, a Chopper circuit and a rotor-sideconverter synchronously, so the reliability of fan off-grid operation of the double-fed wind generating set when a low-voltage and high-voltage cascading fault occurs in a power grid is effectively improved, and continuous active power output of the converters during fault ride-through is guaranteed. The pulse blocking time is determined according to the low-high voltage sudden change amplitude of the power grid, so the low-high voltage cascading failure ride-through capability of the system is simply and efficiently improved.