260results about How to "Reduce peak current" patented technology

A circuit that utilizes most of the energy stored in the bulk capacitor of an AC to DC or DC to DC converter power supply by providing an intermediate converter between a first stage boost converter and a DC-DC converter. When the bulk voltage starts to fall during the hold-up time, the intermediate converter boosts the falling voltage to maintain the regulated DC input to the DC to DC converter while reducing the operating range and increasing the operating duty cycle, so as to increase efficiency, reduce peak current and voltage stresses, reduce the size of output filter components and reduce the size of the bulk capacitance by up to half.

An energy buffer including an electrochemical capacitor can be added to the primary circuit and/or to the secondary circuit of in-motion wireless power transfer system. The energy buffer(s) can smoothen the power delivered by the power grid and captured by a vehicle passing over an array of transmit coils through in-motion wireless power transfer. The reduction in the transient power transfer can reduce the peak current that flows through various components of the in-motion wireless power transfer system including a vehicle battery on the vehicle, and prolong the life of the in-motion wireless power transfer system.

The invention relates to a method for controlling drive pulses of a DAB type bidirectional isolation DC-DC converter. The method for controlling the drive pulses of the DAB type bidirectional isolation DC-DC converter comprises the steps of firstly, carrying out drive pulse control on the DAB type bidirectional isolation DC-DC converter based on a drive pulse working principle; and then inferring relevant formulas in the mode of control, and carrying out characteristic analysis and verification. The method for controlling the drive pulses of the DAB type bidirectional isolation DC-DC converter only needs to control a single variable, is simple and practical, applicable to the state of light load of a system, simple in algorithm, convenient to achieve, and prone to feedback regulation, reduces stress of devices, and effectively improves system efficiency when the system is in light load.

A surface NMES stimulation device the device has a control processor, a voltage regulator connected to a high voltage supply, a bridge of control switches, and electrodes or electrode terminals connected in the bridge to receive drive signals via the control switches. The processor directs a drive scheme for the bridge control switches in which charge build-up on a user's skin is allowed to dissipate to ground in an inter-pulse interval. An isolation capacitor isolates the high voltage supply from the electrodes, and charging of the capacitor only occurs if a switch allows it. Sensors senses supply voltage and bridge current and the processor monitors there to determine further stimulation and faults.

The invention relates to an optimal current waveform controlling method for a current type two-way DC-DC convertor, and belongs to the power electronics field of the high frequency switch power source direction. According to the method, by simultaneously adjusting the duty ratio of a low voltage side and the conductive logic of two bridge arm switching tubes of a high voltage side, so that when the voltage of the low voltage side of a transformer reaches zero, a leakage inductance current of the transformer maintains the cocurrent change, the dynamic change of the leakage inductance current is completed so that the maximum peak value can be reached, when the voltage of the low voltage side of a transformer does not reach zero, the peak value of the leakage inductance current is guaranteed to be minimum under the condition of transmitting the same power. Therefore, the current-circulation loss and the conduction loss of circuits and the switching tubes and the current stress of power devices are greatly reduced, and the efficiency and performance of the circuits are improved. Meanwhile, although conducting logics of secondary side switching tubes during a boost mode and a buck mode are slightly different, the seamless switching can be achieved between the boost mode and the buck mode, so that a closed loop real-time control on the system can be easily achieved.

The invention discloses a motor synchronous modulation method and a control system thereof. Under the offline state, the optimization calculation on the switching angle of an inverter is carried out according to the total harmonic loss of the motor; the modulation ratio is taken as an independent variable; m switching angles (Alpha1, Alpha2,..., Alpha m) corresponding to the modulation ratio are worked out by the optimization algorithm; the modulation frequency division number obtained by the m switching angles is 2m+1; the m switching angles are used as a data table memorized in a memory; during the working process, according to the target modulation ratio, the m switching angles can be obtained by searching the data table, thus carrying out conduction control on the inverter switch device. By adopting the method and the technical scheme described by the control method, the running track of the motor magnetic chain can be a regular polygon so as to reduce the output current harmonicsof the inverter, thus improving the control performance of the transmission system.

The invention discloses an LCC-MMC hybrid three-terminal high-voltage direct current transmission system and a DC fault fast current limiting method thereof. The LCC-MMC hybrid three-terminal high-voltage direct current transmission system comprises a transmitting end converter station LCC and receiving end converter stations, namely, two hybrid MMCs, and redesigns a control architecture of the existing hybrid direct current transmission system. The DC fault fast current limiting method provides a fault current limiting control strategy for the LCC and the MMCs, suppresses the magnitude of fault currents of the transmitting end LCC and the receiving end MMCs by adopting an additional control strategy during the system DC fault transient process, quickly suppresses the DC fault current whena DC fault occurs in the system, and protects current converter equipment. The LCC-MMC hybrid three-terminal high-voltage direct current transmission system and the DC fault fast current limiting method thereof realize the independent control of AC-DC control through AC-DC decoupling, enable each bridge arm to output a bridge arm output voltage reference value, and realize the control of AC and DC currents at the same time; and when a direct current fault occurs, the MMCs operate near a zero direct voltage through quickly switching the transmitting end LCC into an inverting state and negatively inputting full-bridge sub-modules of the receiving end hybrid MMCs, thereby realizing elimination of the DC fault current.

The invention relates to a buck-boost converter used in a defrillating and pacing power supply, which comprises a flyback converter, a PWM controller which is operated in a mode of critical current, an adjustable constant-current source and an isolated feedback circuit, wherein the flyback converter is used for realizing voltage change; the adjustable constant-current source is used for converting control voltage into a current control signal which is proportional with the control voltage; two input ends of the isolated feedback circuit are connected with a voltage output end of the flyback converter and the current control signal respectively; output voltage of the flyback converter is overlaid with the current control signal, and adjusting voltage is outputted and acts on a feedback voltage end of the PWM controller which is operated in the mode of critical current; and the PWM controller controls the switch-on time of a switch tube of the flyback converter according to the adjusting voltage and drives output voltage of the flyback converter to change. The buck-boost converter realizes isolation of input and output of the converter; the output voltage can be continuously changed within a large range lower than or higher than input voltage; and the control voltage VC and the output voltage form a linear proportional control relation.

A field oriented control system for a brushless wound field synchronous machine that determines positioning of a rotor for the machine from exciter stator electrical potentials and current harmonics.

Disclosed is a level shift circuit. The level shift circuit comprises a first level shift circuit, an inverter and a second level shift circuit. The first level shift circuit is used for outputting a first level signal according to an input signal; the first input end of the first level shift circuit is connected with the input signal; the second input end of the first level shift circuit is connected with an anti-phase incoming signal; the level overturn speed of the first level signal outputted by the first level shift circuit is smaller than the level overturn speed of the input signal; the inverter is used for inverting the first level signal; the second level shift circuit is used for outputting a second level signal according to the first level signal; the first input end of the second level shift circuit is connected with the first level signal; the second input end of the second level shift circuit is connected with the first level signal inverted by the inverter; and the level overturn speed of the second level signal outputted by the second level shift circuit is smaller than the level overturn speed of the first level signal. The level shift circuit provided by the invention has the advantage of low power dissipation.

The invention discloses a device and a method for assisting gas metal arc welding by using externally applied magnetic fields, belonging to the field of welding techniques under the action of magnetic fields. The device comprises necessary conventional equipment for gas metal arc welding, a short circuiting transfer detection circuit, an exciting drive circuit, a main exciting circuit and a magnetic head device. According to the invention, during droplet short circuit period, a transverse pulsed magnet field which is acted on a short circuit liquid bridge and perpendicular to a welding-wire axis can be generated so as to promote the advanced fracture of the short circuit liquid bridge; and compared with the conventional method, the method provided by the invention has the advantages that the peak current during the short circuit period is reduced, the induced explosion and splash are lowered, and the regularity of a short circuit cycle in the process of short circuiting transfer welding can be improved. The device disclosed by the invention is simple in manufacturing, and the welding process of short circuiting transfer is obviously improved.

The invention relates to a portable lottery ticket machine, which comprises a main case body, a case body cover, a display, a host machine, a printer and a keyboard. The display is arranged on the case body cover, the host machine and the printer are arranged in the main case body, a host machine seal cover is arranged above the host machine, the keyboard is arranged on the host machine seal cover, the printer and the keyboard are respectively connected with the host machine through different data lines, and the portable lottery ticket machine is also provided with a case body locking device used for locking the case body cover and the main case body. The portable lottery ticket machine can carry out movable ticket sale and is suitable to moving lottery ticket sale for underdeveloped areas or small towns, villages and even peripheral mountain areas.

The invention discloses an efficient method for frequency conversion and energy saving of an oil pumping unit. The efficient method comprises the following steps that after a device is started, a system is initialized and the balance degree of the oil pumping unit is adjusted; whether the oil pumping unit is in a power frequency operation mode or in a frequency conversion operation mode is judged; in the frequency conversion operation mode, whether a frequency converter breaks down or not is judged, and if not, a stroke frequency adjustment mode of the oil pumping unit is judged; in an automatic stroke frequency adjusting mode, indicator diagram data are collected and whether the oil pumping unit breaks down or not is judged according to an indicator diagram; if the oil pumping unit does not break down, whether the oil pumping unit needs interval pumping control or not is judged; if the oil pumping unit does not need the interval pumping control, the stroke frequency of the oil pumping unit is automatically adjusted. The method for frequency conversion and energy saving of the oil pumping unit has the advantages that the adjustment of the balance degree, the optimal operation stroke frequency and the optimal interval pumping mode is conducted according to the working conditions of the oil pumping unit, the states of high efficiency and low energy consumption of the oil pumping unit can be kept, and the problems of high energy consumption and low efficiency in the operation process of the oil pumping unit can be solved.

The invention provides a direct torque control method for the high load capability of a dual-three phase permanent magnet synchronous motor. Center points of two sets of windings of the dual-three phase permanent magnet synchronous motor are connected together, third and fifth harmonics in a high ratio are contained in the back electromotive force of the winding, a six-phase inverter is used to output a voltage vector, a direct control method on a dual-electromagnetic torque and a stator flux linkage is built in a fundamental wave plane and a fifth harmonic plane, and the electromagnetic torque in the fifth harmonic plane is used for enhancing the load capability of the motor. Peak current of a stator winding can be reduced, the center points of two sets of windings are connected together, and current flowing through a remaining healthy phase winding is used for enhancing the load capability in the case of motor winding fault.

The invention relates to a hydraulic system used for adjusting the buoyancy of a full-ocean-depth submersible. The hydraulic system comprises a hydraulic power source, a seawater hydraulic power source, a water ballast space and a water ballast space control valve set. The hydraulic power source drives the seawater hydraulic power source to work, and water injection or water drainage of the interior of the water ballast space is controlled through switching of the water ballast space control valve set, and thus adjusting of the buoyancy of the full-ocean-depth submersible is achieved. The hydraulic system is simple in structure and convenient to use; and a pressure cylinder of the hydraulic system is driven by oil pressure and outputs aqueous media, compared with traditional axial plunger type seawater pumps, the machining cost of the hydraulic system is low, and the flow is larger, the service life is long, the reliability is good and the volume efficiency is high with the same volume. The submersible buoyancy adjusting working condition of the hydraulic system has quite low requirements for pumping flow pulsation, the hydraulic system is better agree with the submersible buoyancy adjusting working condition than the axial plunger pumps, and the outlet pressure of the pressure cylinder can meet the full-ocean-depth application requirements by adjusting the pressure ratio of the pressure cylinder.

The invention provides an electromagnetic resonance control circuit, an electromagnetic heating device and a method for controlling a transistor. The electromagnetic resonance control circuit comprises a power module, a resonance circuit, the transistor and a controller, the resonance circuit is connected to the power module, the transistor is arranged between the resonance circuit and the ground, and used for executing the power-on or power-off operation according to pulse width modulation signals sent by the controller to control the work state of the resonance circuit, and the controller is connected to the power module and the control end of the transistor, and used for adjusting the duty ratio of the pulse width modulation signals sent to the transistor according to the change condition of voltages output to the resonance circuit by the power module to control the power-on time of the transistor. According to the technical scheme, the power-on time of the transistor can be controlled according to the voltages output to the resonance circuit, power output is increased in a low-voltage area, power output is reduced in a high-voltage area, the peak voltage and the peak current of the transistor are reduced under the condition of identical power, and therefore the transistor is effectively protected.

The invention relates to a charge pump circuit with low power consumption. The charge pump circuit comprises a multiphase clock generation circuit, a charge transmission transistor, a substrate adjustment circuit of the charge transmission transistor and a capacitor element, wherein one end of the capacitor element is connected to a serial connection joint of the charge transmission transistor, and the other end is connected to clock signals generated by the multiphase clock circuit; the plurality of clock signals output by the multiphase clock generation circuit have different phases, and each clock signal is connected to the corresponding capacitor element so that the charge pump only charges one capacitor when working at different moments. The invention can effectively avoid larger transient current and transient power consumption caused by charging the plurality of capacitors in the traditional charge pump circuit at the same time, and thereby the dynamic power consumption and power peak current are reduced when the charge pump works.

The present invention discloses an energy feedback elevator traction driving system control method based on a matrix converter. Based on the power balance active damping inhibition resonance method and a model prediction control method, according to the motor side power requirement, the power grid side reference input current is obtained, current high-frequency components corresponding to the high-frequency components in the input voltage are added into the reference input current to obtain the active damping control of the grid-connected current with high sine degree, the interlace control advantage of a two-channel circuit itself is added to effectively inhibit the grid-connected current harmonic wave and improve the input current sine degree. The model prediction control is performed at the motor side to derive and establish the mathematical model of the system and take two-channel three-level permanent magnet motor torque and linkage as control objects, the required variable is subjected to sampling according to the system requirement to predict the value of the next moment under all the actions of all the switch states, and a value function through human construction is employed to select a switch state which is the most suitable for the requirement so as to allow the system to obtain superior input/output performances.

The invention provides a control method for improving the light-load efficiency of a DAB-type DC-DC converter and belongs to the technical field of modulation of bidirectional isolation DC-DC converter power switch tubes. Switch tubes on a diagonal of a full bridge at a side generate phase shift when a driving pulse is controlled so as to output a three-level voltage waveform. A full bridge at the other side is not required to be subjected to any phase shift control. The control method comprises two control modes. In the first mode, phase shift is performed on a bridge at an input side but is not performed on a bridge at an output side. In the second mode, phase shift is performed on the bridge at the output side but is not performed on the bridge at the input side. The control method is suitable for converter small-medium power output, greatly reduces the peak value and the effective value of the current flowing through a transformer, an inductor, and a switch device, effectively decreases device stress, greatly reduces system reactive power and system loss, and improves system efficiency.

The invention relates to a comprehensive low voltage ride-through method for a doubly-fed fan based on a stator series dynamic reactor. The method comprises the following steps: when the grid voltagedrop is detected, performing control according to a transient control mode 1, wherein the transient control mode 1 is a comprehensive traversing mode in which the stator series reactor with a large value is input and a RSC adopts a control strategy of active transient flux linkage attenuation, and the setting principle of the large reactor in the mode 1 is to ensure that the peak value of the rotor current does not exceed the limit after the fault occurs; observing the modulus value of the transient induced electromotive force in real time, and switching to a control mode 2 when the modulus value decays to the set threshold value, wherein the setting principle is to ensure that the rotor current does not exceed the limit after reactor witching; restoring the normal control of the fan, andcutting off the series reactor after a delay of 100 ms, when the grid voltage returns to normal.

The invention discloses a bias voltage generating circuit and a memory of a line decoder. The bias voltage generating circuit of the line decoder is suitable for providing a first bias voltage and a second bias voltage to the line decoder. The bias voltage generating circuit of the line decoder comprises a high voltage detecting unit, a level shifting unit, a first driving unit and a second driving unit, wherein the high voltage detecting unit is suitable for detecting the power supply voltage of the line decoder and outputting a detection control signal; the level shifting unit is suitable for receiving the detection control signal and outputting a driving signal under the control of the detection control signal; the first driving unit is used for providing the first bias voltage under the control of the detection control signal; and the second driving unit is used for providing the second bias voltage under the control of the detection control signal. According to the technical scheme of the bias voltage generating circuit of the line decoder, the first bias voltage and the second bias voltage are respectively output through two driving units, so that the power loss in the process that a memory is subjected to erasure operation is reduced.

A fuse circuit comprises a plurality of enable fuse units and a plurality of fuse sets. Current flows at a reset mode in the plurality of enable fuse units, and the flowing of current is controlled by enable signals outputted from the plurality of enable fuse units in the plurality of fuse sets. In the fuse circuit, a fuse set connected to the end of the enable fuse unit whose fuse is disconnected selectively performs a reset operation, thereby reducing peak current to decrease the whole current consumption.

The invention provides an invert plasma cutter. The cutter is to add a power correcting device based on the conventional plasma cutter to ensure that input voltage of the invert plasma cutter is synchronized with current phase position, aberrance of the current wave shape is improved, meanwhile, harmonization can be inhibited, peak current and effective current are reduced to improve power efficiency finally. In the invert plasma cutter, a major power element is fixed on a radiator; a rear cover is provided with a rear fan; a printed circuit board is arranged in the middle of the cutter; the printed circuit board is provided with a middle fan; the rear fan, the middle fan and the major heat element are positioned on the same horizontal line; the rear fan pumps outside air through a louver of the rear cover; and the middle fan blows internal heat outside the cutter through the reticular radiation pores on the front cover and the louver on the side surface, thereby forming an excellent horizontal tunnel. The cutter improves the radiation performance, improves service life of the device, and ensures stability and reliability of the whole device.