85 results about "Current ramp" patented technology

A pulsed waveform welding operation is implemented by reference to a commanded wire feed speed set by an operator. The wire feed speed is set on a wire feeder, and a signal representative of the commanded wire feed speed is applied to a power supply. The power supply control circuitry references a look-up table in which pulsed waveform parameters are provided based upon wire feed speed. The parameters may include multiple parameters such as pulse frequency, peak current, background current, and current ramp rates. The control circuitry commands power conversion circuitry to generate the commanded waveform as a function of the commanded wire feed speed.

This disclosure describes a non-dissipative snubber circuit configured to boost a voltage applied to a load after the load's impedance rises rapidly. The voltage boost can thereby cause more rapid current ramping after a decrease in power delivery to the load which results from the load impedance rise. In particular, the snubber can comprise a combination of a unidirectional switch, a voltage multiplier, and a current limiter. In some cases, these components can be a diode, voltage doubler, and an inductor, respectively.

A step down switching regulator circuit that is particularly well-suited to drive high power LEDs includes a crossover conduction mode (XCM) control circuit that maintains operation at the crossover point between continuous conduction mode (CCM) and discontinuous conduction mode (DCM). This XCM operation provides an inductor current waveform that ramps up and down between zero and a desired maximum current. One or more comparators in the XCM control circuit can be used to control switching between the inductor current ramp up and ramp down phases. In this manner, complex feedback loop logic and PID controlled PWM signal generation logic can be avoided, and the need for external sense resistors and associated interface pins can be eliminated.

Operation of a switching power converter having an output capacitor having a small equivalent series resistance (ESR) is stabilized and jitter reduced by sensing capacitor current with gain and combining the resulting signal with the output voltage signal to provide a feedback signal to control switching of the power converter. capacitor current can be sensed without interfering with operation of the filter capacitor by providing a branch circuit having a time constant matched to the output or filter capacitor but an arbitrarily high impedance so as to be effectively lossless. The gain provided in the capacitor current signal can be tuned to provide optimally short settling time after load transients; generally within one switching cycle. Matching of time constants and / or tuning of gain can be performed automatically.

A step down switching regulator circuit that is particularly well-suited to drive high power LEDs includes a crossover conduction mode (XCM) control circuit that maintains operation at the crossover point between continuous conduction mode (CCM) and discontinuous conduction mode (DCM). This XCM operation provides an inductor current waveform that ramps up and down between zero and a desired maximum current. One or more comparators in the XCM control circuit can be used to control switching between the inductor current ramp up and ramp down phases. In this manner, complex feedback loop logic and PID controlled PWM signal generation logic can be avoided, and the need for external sense resistors and associated interface pins can be eliminated.

A method of predicting by non-invasive testing the available energy of a battery at any state of charge by acquiring data of the parameters of internal resistance (IR), open circuit voltage (OCV) and temperature (T), the points of voltage and current of the slope on a positive current ramp of Vup and Iup at the transition from charge to overcharge and on a negative current ramp of Vdn and Idn at the transition from overcharge to charge for a plurality of batteries. Next an algorithm in the form of a linear equation is developed using this data. The available energy of a battery under test is predicted by acquiring from it the numerical data values of these parameters and applying them to the algorithm.

A system for controlling a weld-current in an arc welding apparatus for short arc welding comprising a current regulator included in a voltage feedback loop from a power supply to a welding electrode and a ramp generator arranged to provide current ramps during a short circuit phase at said welding electrode.

A hybrid-technology metal detector, using pulse-induction and sine-wave excitation of the transmitter coil alternately, in rapid succession. The energy stored in the transmitter coil, in the pulsed mode, is used to shock-excite a high-Q circuit formed by the coil and a parallel capacitor into oscillations in the sine-wave mode. The multiplicative action of the circuit Q causes high currents to flow in the transmitter coil, causing high fluxes to be impressed on the searched area, with increased sensitivity as a result. Using a linear coil-current ramp to assess and minimize the coupling between the transmitter and receiver coils permits effective separation of the reactive and resistive components of the target signals, making accurate identification of targets possible.

An electric arc welder with a waveform generator controlled to create a welding process involving current flow between an electrode and a workpiece wherein the welding process comprises a succession of pulse waveforms, each having a current ramp up portion, a peak current portion, a current ramp down portion and a background current portion, a voltage sensing circuit to sense a short circuit between the electrode and the workpiece and a reset circuit to reset the waveform generator upon sensing of a short circuit. The preferred electrode is a solid wire which may be in the form of a metal cored wire.

A method of predicting by non-invasive testing the available energy of a battery at any state of charge by acquiring data of the parameters of internal resistance (IR), open circuit voltage (OCV) and temperature (T), the points of voltage and current of the slope on a positive current ramp of Vup and Iup at the transition from charge to overcharge and on a negative current ramp of Vdn and Idn at the transition from overcharge to charge for a plurality of batteries. Next an algorithm in the form of a linear equation is developed using this data. The available energy of a battery under test is predicted by acquiring from it the numerical data values of these parameters and applying them to the algorithm.

This disclosure describes a non-dissipative snubber circuit configured to boost a voltage applied to a load after the load's impedance rises rapidly. The voltage boost can thereby cause more rapid current ramping after a decrease in power delivery to the load which results from the load impedance rise. In particular, the snubber can comprise a combination of a unidirectional switch, a voltage multiplier, and a current limiter. In some cases, these components can be a diode, voltage doubler, and an inductor, respectively.

An electric arc welder with a waveform generator controlled to create a welding process involving current flow between an electrode and a workpiece wherein the welding process comprises a succession of pulse waveforms, each having a current ramp up portion, a peak current portion, a current ramp down portion and a background current portion, a voltage sensing circuit to sense a short circuit between the electrode and the workpiece and a reset circuit to reset the waveform generator upon sensing of a short circuit. The preferred electrode is a solid wire which may be in the form of a metal cored wire.

A buck-boost regulation methodology operable, in one embodiment, with a single inductor, four-switch (S1-S4) buck-boost regulator configured for DCM. Buck-boost transition switching control is operable when inductor charge time exceeds a max charge time, and inductor discharge time exceeds a max discharge time, and includes: (a) during charge transition cycles, at the end of the max charge time, if IL is less than a predetermined peak current IL<sub2>—< / sub2>MAX, switching S2 on (grounding the output side of the inductor) and S4 off, causing IL to increase (a rapid S1S2 charging current ramp), until IL reaches IL<sub2>—< / sub2>MAX, and (b) during discharge transition cycles, at the end of the max charge time, if IL is greater than zero, switching S1 off and S3 on (grounding the input side of the inductor), causing IL to increase (a rapid S3S4 IL discharging current ramp), until IL reaches zero.

A buck-boost regulation methodology operable, in one embodiment, with a single inductor, four-switch (S1-S4) buck-boost regulator configured for DCM. Buck-boost transition switching control is operable when inductor charge time exceeds a max charge time, and inductor discharge time exceeds a max discharge time, and includes: (a) during charge transition cycles, at the end of the max charge time, if IL is less than a predetermined peak current IL<sub2>—< / sub2>MAX, switching S2 on (grounding the output side of the inductor) and S4 off, causing IL to increase (a rapid S1S2 charging current ramp), until IL reaches IL<sub2>—< / sub2>MAX, and (b) during discharge transition cycles, at the end of the max charge time, if IL is greater than zero, switching S1 off and S3 on (grounding the input side of the inductor), causing IL to increase (a rapid S3S4 IL discharging current ramp), until IL reaches zero.

A metal detector using a linear current ramp followed by an abrupt current transition to energize the transmitter coil. The constant emf imposed on the target during the current ramp permits separation of transient voltages generated in response to eddy currents in the target and its environment from the voltages arising as a result of an inductive imbalance of the coil system The temporal separation of the various voltages makes reliable differentiation between ferrous and non-ferrous targets possible.

An average current mode buck-boost DC to DC converter has a buck stage coupled between an input voltage source terminal and an output terminal. A boost stage is coupled between the input voltage source terminal and the output terminal. A current ramp control circuit generates a ramp signal for driving the buck and boost stages, the ramp signals being coupled to the buck and boost stages. A constant voltage related to the desired output voltage by a constant is applied directly to both a voltage control feedback loop for adjusting the output voltage and directly to an input to the current ramp control circuit, whereby the output voltage can be shifted from one voltage to another by feedforward control.

A buck-boost regulation methodology operable, in one embodiment, with a single inductor, four-switch (S1-S4) buck-boost regulator configured for DCM. Buck-boost transition switching control is operable when inductor charge time exceeds a max charge time, and inductor discharge time exceeds a max discharge time, and includes: (a) during charge transition cycles, at the end of the max charge time, if IL is less than a predetermined peak current IL—MAX, switching S2 on (grounding the output side of the inductor) and S4 off, causing IL to increase (a rapid S1S2 charging current ramp), until IL reaches IL—MAX, and (b) during discharge transition cycles, at the end of the max charge time, if IL is greater than zero, switching S1 off and S3 on (grounding the input side of the inductor), causing IL to increase (a rapid S3S4 IL discharging current ramp), until IL reaches zero.

A system and method for detecting and correcting excess current in a power amplifier in a transmit chain of a mobile terminal are provided. Over current detection and correction circuitry compares a current detection signal indicative of an output current of the power amplifier to a maximum current ramp during ramp-up for a transmit burst. If the current detection signal exceeds the maximum current ramp, then a power control signal controlling a supply voltage provided to the power amplifier circuitry is reduced, thereby reducing the output power and output current. Over voltage detection and correction circuitry compares a voltage detection signal indicative of an output voltage of the power amplifier to a maximum voltage ramp during ramp-up for the transmit burst. If the voltage detection signal exceeds the maximum voltage ramp, then the power control signal is reduced.

Methods and systems are provided to reduce stimulated Brillouin scattering in high power optical fiber amplifiers. In an embodiment, a seed source includes a narrow linewidth semiconductor laser driven with a current ramp that simultaneously sweeps the optical power and the lasing frequency at a rate fast enough to reduce stimulated Brillouin scattering.

The present invention provides a system and method for dynamically increasing the numeric gain applied to the temperature loop in a DBR laser control system in response to the anticipated wavelength change that occurs as a tuning current ramp is in progress. In accordance with a preferred embodiment of the invention, the feedback control signal to the laser's TEC is overcompensated for, and as a result, the system is forced to respond much faster, thermally, to the anticipated wavelength shift, thus providing improved real time wavelength stabilization to the control system. The implementation of the increased numeric gain can be carried out through software and / or firmware.

A capacitive load drive circuit may comprise a high current drive amplifier configured to be coupled to a capacitive load during a high current ramp up of the voltage across the capacitive load to a cut off voltage; a low current drive amplifier configured to be connected to the capacitive load during a low current ramp up of the voltage across the capacitive load, from the cut off voltage to a maximum voltage across the capacitive load; and the high current drive amplifier configured to be connected to the capacitive load during a high current ramp down of the voltage across the capacitive load. The low current drive amplifier may be connected to the capacitive load during a period of steady state of the voltage across the capacitive load, intermediate the low current ramp up and the high current ramp down.

Provided are a geographic ramp self-learning method and system for a vehicle. The method comprises the steps of acquiring road information and a slope value of a current driving position of the vehicle in real time; determining whether or not the vehicle travels on a slope road segment according to a gradient value, and if so, caching slope values and road information of respective ramp points; according to the slope values and the road information cached, fitting a quadratic curve y=ax2+bx+c; determining whether or not historical ramp data of the same ramp exists in a database, and if not, storing current ramp data; if yes, respectively comparing fitting coefficients a, b, and c with the corresponding fitting coefficients in the historical ramp data, and judging whether or not the ramp data is updated based on a comparison result. The ramp self-learning method and system can acquire the road information and the slope value of the current driving position of the vehicle in real time, learn and record the geographical ramp on the road with small storage space, have certain fault tolerance, can automatically conduct correction after multiple driving, and maintain the consistency of the ramp data with actual road conditions.

A high speed ramp generator is presented. The high speed ramp generator is advantageous over the prior art because it provides a ramp response without the delay incident with a simple integrator approach. A closed loop system generates a continuous ramp and, in an open loop manner, subtracts a mirror of the current ramp from itself. A switch is provided which when open, triggers an immediate current ramp output that is not dependent on the amplifier or any other component of prior art feedback circuits. Two such ramp generators may be used in tandem to provide alternating portions of a precision ramp signal, such as may be used to cancel the magnetization current induced in the primary of an isolation transformer.

A high speed ramp generator is presented. The high speed ramp generator is advantageous over the prior art because it provides a ramp response without the delay incident with a simple integrator approach. A closed loop system generates a continuous ramp and, in an open loop manner, subtracts a mirror of the current ramp from itself. A switch is provided which when open, triggers an immediate current ramp output that is not dependent on the amplifier or any other component of prior art feedback circuits. Two such ramp generators may be used in tandem to provide alternating portions of a precision ramp signal, such as may be used to cancel the magnetization current induced in the primary of an isolation transformer.

A method of controlling a welding system includes controlling a weld current supplied to an electrode at a current ramp rate and determining an arc length based at least in part on the controlled weld current and a changing arc voltage. The arc length includes a distance between the electrode and a workpiece, and the arc voltage includes a voltage between the electrode and the workpiece.

A pulsed waveform welding operation is implemented by reference to a commanded wire feed speed set by an operator. The wire feed speed is set on a wire feeder, and a signal representative of the commanded wire feed speed is applied to a power supply. The power supply control circuitry references a look-up table in which pulsed waveform parameters are provided based upon wire feed speed. The parameters may include multiple parameters such as pulse frequency, peak current, background current, and current ramp rates. The control circuitry commands power conversion circuitry to generate the commanded waveform as a function of the commanded wire feed speed.

An electric arc welder with a waveform generator controlled to create a welding process involving current flow between an electrode and a workpiece wherein the welding process comprises a succession of pulse waveforms, each having a current ramp up portion, a peak current portion, a current ramp down portion and a background current portion, a voltage sensing circuit to sense a short circuit between the electrode and the workpiece and a reset circuit to reset the waveform generator upon sensing of a short circuit. The preferred electrode is a solid wire which may be in the form of a metal cored wire.

The invention discloses a method and device for controlling the hill start of a vehicle to prevent slip. The method includes the steps that whether the vehicle is in a hill start state or not is detected; the vehicle is continuously locked, the current ramp slope is collected to determine the gradient resistance, and the accelerator depth is collected to determine the driver demand wheel end torque; whether the driver demand wheel end torque is larger than or equal to the gradient resistance or not is judged; if yes, the vehicle is unlocked, and the motor target torque corresponding to the gradient resistance is output to prevent the vehicle from slipping. By means of the method and device, in the hill start, the vehicle is locked first and prevented from slipping backwards; if the driverdemand wheel end torque generated when a driver steps on an accelerator pedal is larger than or equal to the gradient resistance, the vehicle is unlocked only after it is ensured that power output bya vehicle motor can prevent the vehicle from slipping in uphill running, the motor target torque corresponding to the gradient resistance is output to prevent the vehicle from slipping, and thus the problem of hill start slip is thoroughly solved.

In accordance with the invention, there is a battery defect detection method comprising applying a current ramp to a battery; determining a first time (t1) when a current of the battery reaches a maximum current (Ipeak), and determining a second time (t2) when a terminal voltage of the battery reaches a maximum voltage (Vpeak). The method also includes determining a differential (d), wherein (d)= / (t1)−(t2) / , and wherein (d) corresponds to a magnitude of defects in the battery.

An average current mode buck-boost DC to DC converter has a buck stage coupled between an input voltage source terminal and an output terminal. A boost stage is coupled between the input voltage source terminal and the output terminal. A current ramp control circuit generates a ramp signal for driving the buck and boost stages, the ramp signals being coupled to the buck and boost stages. A constant voltage related to the desired output voltage by a constant is applied directly to both a voltage control feedback loop for adjusting the output voltage and directly to an input to the current ramp control circuit, whereby the output voltage can be shifted from one voltage to another by feedforward control.