2107 results about "Ripple" patented technology

The present invention relates to a converter and a driving method thereof. The converter uses an input voltage to generate an output voltage by a main switch's switching and applies power to a load, senses the current flowing to the main switch to generate a sense voltage, uses a first voltage corresponding to the current applied to the load and a sawtooth waveform signal having a first frequency to control a group frequency of the burst mode, controls the main switch's turn-on timing, and uses the first voltage and the sense voltage to determine whether to turn off the main switch, thereby controlling the main switch's switching. The converter determines the start and end of the period for switching according to the result of comparing the first voltage and the sawtooth waveform signal. Therefore, a converter for having a constant group frequency, preventing audible noise, and preventing output voltage ripple, and a driving method thereof, are provided.

A ripple-mode controller provides reliable operation in multi-phase power supply circuits, over a variety of operating conditions. Cross-phase blanking allows the controller to preserve the desired phase relationship between the switching pulses its provides to the different output phases, and permits the controller to operate each output phase at nearly 100% duty cycles. Active current sharing compliments blanking operations by adjusting the width of switching pulses the controller provides to one or more of the output phases based on detecting load current imbalances between the different output phases. With active current sharing, the controller prevents one or more output phases from carrying excessive portions of the load current. Further complimenting its operation, the controller may include virtual ripple generation to increase the noise immunity of its ripple-mode regulation.

A two-stage power converter that dynamically adjusts to output current requirements includes a first stage regulator that provides power to a second stage regulator. The first stage can be a buck converter, and the second stage can be a multiple-phase buck converter. The output voltage of the first stage (intermediate bus voltage Vbus) is varied according to the load current to optimize conversion efficiency. To provide maximum efficiency, the Vbus voltage is increased as load current increases. The Vbus voltage provided by the first stage can be varied by duty cycle or operating frequency control. In another embodiment, the switching frequency of the second stage is varied as output current changes so that output current ripple is held constant. In an embodiment employing a multiple-phase buck converter in the second stage, the number of operating phases are varied as output current changes.

A two-stage power converter that dynamically adjusts to output current requirements includes a first stage regulator that provides power to a second stage regulator. The first stage can be a buck converter, and the second stage can be a multiple-phase buck converter. The output voltage of the first stage (intermediate bus voltage Vbus) is varied according to the load current to optimize conversion efficiency. To provide maximum efficiency, the Vbus voltage is increased as load current increases. The Vbus voltage provided by the first stage can be varied by duty cycle or operating frequency control. In another embodiment, the switching frequency of the second stage is varied as output current changes so that output current ripple is held constant. In an embodiment employing a multiple-phase buck converter in the second stage, the number of operating phases are varied as output current changes.

The present invention is a system and a method that controls the current limit such that it is maintained within a small range for any acceptable input voltages, e.g., 90 to 264 Volts RMS, causes the output voltage of a PWM controller to drop as the output load increases so as to maintain a constant current output, and does cycle by cycle calculation compensating for the VIN ripple output from the bridge and bulk filter capacitor so that no loop filter is required in the constant current mode.

Systems, devices, and methods for measuring a peak to peak switching ripple in a voltage present on welding output terminals are provided. The systems, devices, and methods may also be utilized to determine, during a welding operation, a weld cable inductance based on the measured peak to peak voltage ripple.

A method and apparatus are disclosed for single-inductor multiple-output switching converter design. With the proposed freewheel switching control, this converter operates in a pseudo-continuous conduction mode (PCCM) and is capable of handling large load currents with a much smaller current ripple and peak inductor current, while retaining low cross regulation. It can also work in discontinuous conduction mode (DCM) for high efficiency at light loads. This design can be applied to have single or multiple outputs and for different types of DC-DC conversions.

In a pulse frequency modulated (PFM) voltage regulator, a PFM switching controller is provided to generate a PFM switching signal for converting a DC voltage source to an output voltage. A minimum OFF-time controller provides the PFM switching signal with a minimum OFF-time. In response to the output voltage, a feedback circuit generates a feedback signal. When the output voltage is lower than a predetermined target voltage, an OFF-time prolonging circuit prolongs the minimum OFF-time in response to the feedback signal. In other words, a time of delivering energy to a capacitor from an inductor may be prolonged by the OFF-time prolonging circuit. Therefore, a ripple of the output voltage is effectively reduced when the PFM voltage regulator is operated in a heavy loading condition.

A switched-capacitor DC-DC converter has a reconfigurable power stage with variable gain ratio and / or interleaving regulation for low ripple voltage, fast load transient operation, variable output voltage and high efficiency. Since the power stage has multiple switches per capacitor, the converter exploits reconfigurable characteristics of the power stage for fast dynamic control and adaptive pulse control for tight and efficient voltage regulation.

A method of controlling a brushless permanent-magnet motor that includes rectifying an alternating voltage to provide a rectified voltage having a ripple of at least 50%, and exciting a winding of the motor with the rectified voltage. The winding is excited in advance of zero-crossings of back EMF by an advance period and is excited for a conduction period over each electrical half-cycle of the motor. The advance period and / or the conduction period are then adjusted in response to changes in the speed of the motor and / or the RMS value of the alternating voltage so as to maintain constant average power. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

An all-digital class-D audio amplifier and method of digitizing an analog signal comprises a pulse-width modulation (PWM) wave generator for generating a PWM wave; an interpolator for receiving an input audio signal, up-sample the input audio signal; and down-sample the input audio signal to a PWM wave switching frequency; an audio speaker for broadcasting an amplified version of the input audio signal; a pair of MOSFETs driven by the PWM wave and the input supply voltage, wherein the pair of MOSFETs transmit the amplified version of the input audio signal to the audio speaker; a natural-sampling and pre-distortion circuit adapted to (i) generate a pre-distorted natural-sampling frequency point for the PWM wave switching frequency, and (ii) account for digitized power supply ripples for an input supply voltage used to drive the audio speaker; and an analog-to-digital converter (ADC) adapted to digitize the power supply ripples or distortion.

There is provided by this invention a system for supply power utilizing a power supply having an adaptive feedforward circuit that uses a gating circuit to periodically apply a feedback signal to an integrator circuit in order to develop an optimal level of a scaled feedforward signal that is used to diminish perturbations of the output of the power supply due to ripple and transient voltages present at the DC bus that supplies power to the power supply. The gating circuit is synchronized to the periodic ripple in the DC bus voltage.

A system and a method for to use multiple power sources for supplying power to a load. The system and method use a triggering system to automatically and substantially cancel a ripple component of the input current drawn by the system. A master power source and a slave power source supply power to the load. The triggering system results in the two power sources having switching frequencies that are substantially equal and switching cycles that are substantially 180° out of phase. Further, the method and the device contemplate the use of a local oscillator in the triggering system to ensure that the slave power source is triggered to the on position at a point in the switching cycle of the master power source that is approximately 180° out of phase with a leading edge of the master switching drive signal. The system and method are advantageously used to provide a power factor correction front-end for a switch-mode power supply. Power supplies with a diverse array of relationships between power supplied and switching frequency can be used.

Disclosed is a switched-mode power supply including an inductor which is connected between a voltage input terminal to which a DC voltage is input and an output terminal to which a load is connected, a driver switching element which intermittently feeds a current to the inductor and a control circuit which generates a control pulse according to a feedback voltage from output side and controls on / off of the driver switching element. The control circuit includes a voltage comparison circuit which compares the feedback voltage to a predetermined voltage and a pseudo ripple generator circuit which generates a pseudo ripple voltage having a predetermined amplitude, and the control circuit injects a ripple component in a transmission path of the feedback voltage based on the pseudo ripple voltage generated by the pseudo ripple generator circuit.

The invention discloses a multiphase phase stagger parallel connection two-stage converter which comprises a control circuit and two resonance conversion circuits with pre-stage regulators, the resonance conversion circuits are in parallel connection between an input positive and negative bus and an output positive and negative bus. Resonance circuits of the resonance conversion circuits with the pre-stage regulators open loop to work, and through the pre-stage regulators, output voltage control is realized. The control circuit controls each resonance conversion circuit to work with same frequency and phase stagger, and through current feedback control, same output current of each resonance conversion circuit is ensured. According to the invention, an uneven current problem of each resonance conversion circuit caused by parameter difference is solved, and ripple current of an input terminal and an output terminal of a circuit is reduced.

The invention provides a PFC (power factor correction) control method with high input power factor and a control circuit thereof. The method comprises the steps of controlling a switching tube to be switched on and switched off according to the principle of leading impulse area to be equivalent, and leading input inductive current and sinusoidal half-wave current to have the equivalent impulse area in each switching period, thereby realizing the high power factor (PF); furthermore, the higher the switching frequency, the closer to 1 the PF value is. In the control circuit, a circuit topological structure of a Boost converter and a control circuit for realizing a variable duty ratio sequence jointly constitute a PFC stage of a commonly used LED (light-emitting diode) driving power supply, the front stage of the PFC stage is connected with the output end of a non-controllable rectifier bridge of a single-phase diode via an input filter capacitor, the back stage of the PFC stage is connected with a DC / DC (direct current / direct current) stage of the commonly used LED driving power supply via an output filter inductor and an output filter capacitor. By adopting the PFC control method, not only the very high input power factor can be realized, but also output voltage ripple can be reduced; furthermore, the control circuit is simple and easy to realize an analog circuit, thereby being conductive to large-scale integration.

The invention discloses a Boost type isolated DC / DC converter and a control method of the Boost type isolated DC / DC converter. The Boost type isolated DC / DC converter is composed of a primary side circuit, an auxiliary side circuit, an ideal transformer and a two-port passive network, wherein the primary side circuit is composed of a full-bridge unit circuit where interleaved Boost circuits are integrated, the auxiliary side circuit is composed of a rectifying circuit, the two-port passive circuit is composed of an inductor and a capacitor and is an energy transmitting unit, and the transformer is used for achieving isolation and transformation. Two interleaved Boost input inductors are connected in the middles of two bridge arms of the full-bridge unit circuit, and therefore the gain range of the isolated DC / DC converter is widened, and input current ripples are reduced; frequency-fixed PWM control is adopted, the duty ratio D of a bridge arm switching tube is controlled, and therefore the output voltage can be adjusted. The Boost type isolated DC / DC converter and the control method have the advantages of being wide in input voltage range, small in input current ripple, fixed in switching frequency, capable of allowing soft switching to be achieved, small in switching loss and the like, and are particularly suitable for renewable energy power generation systems and other systems.

The bi-directional DC / DC converter has zero voltage switching (ZVS) soft switching capability resulting in a higher efficiency, and provides reduction of the switching losses due to higher switching frequencies. The capability of operation in higher frequencies results in reducing the size of passive components including inductance and capacitors. The subject DC / DC converter is capable of operating with three voltage levels in both power flow directions, thus providing flexibility in the voltage control and attaining lower inductor current ripple and lower switch voltage ratings. DC link capacitors are replaced with ultra capacitor banks split in two.

Methods and circuitry for combining the outputs of multiphase power converters which greatly improves the transient response of the power conversion system are presented in a variety of embodiments. Transformers (e.g., 59, 60, 61, 62) may be used to accomplish the combining function, and with properly phased and connected windings it is possible to achieve a great reduction in output ripple current and a simultaneous reduction in transistor ripple current, which give the designer freedom to reduce the value of the system output inductor (e.g., 68), improving transient response.

A mobile communication terminals RF performance adaptive temperature compensation device, including RF modules, analog baseband modules, digital baseband modules, as well as temperature detection module; temperature detection module contains DC Power Supply, the precision series resistor and thermistor, also includes and with the stated thermistor the elimination of the voltage ripple module; a mobile communication terminals RF performance adaptive temperature compensation method, the temperature will be calculated DAC value and the temperature compensation terminal comparison table, calculated on the RF transmitter power and receiver gain compensation value and realize the RF parameters of temperature compensation. This invention using thermistor, high-precision resistors with terminal software-controlled methods, the environmental temperature can be achieved automatically detect, judgment, and in accordance with the terminal RF performance parameters expected accurate target compensation to enable terminals to meet the national standard of technical indicator.

The invention discloses a wide-range bidirectional conversion circuit and a control method. The wide-range bidirectional conversion circuit comprises a three-stage bidirectional converter and a control unit, and the three-stage bidirectional converter is formed by sequentially connecting a non-isolated DC / DC converter, an isolated DC / DC converter and a DC / AC inverter. When the system works in theforward direction, a direct-current power supply or energy storage equipment realizes grid-connected energy feedback through the non-isolated DC / DC converter, the isolated DC / DC converter and the DC / AC inverter; and during reverse working, an alternating voltage supplies power to a direct-current load or charges an energy storage device through a rectifying circuit, the isolated DC / DC converter and the non-isolated DC / DC converter. In order to adapt to different power levels and realize higher input current ripple control, the non-isolated converter adopts a multi-phase interleaved parallel structure; and in order to further broaden the requirements of input and output ranges in practical application, the isolated converter can be controlled by adopting a full-bridge / half-bridge variable structure. The whole system has the advantages of wide input direct-current voltage range, wide output alternating-current voltage range, wide load range, small current ripple, high-frequency isolation, high efficiency, energy conservation, environmental protection and the like.

The invention belongs to the technical field of power electronic application, and especially relates to a wide-input direct current inverter topology and a feedforward average current control method thereof. The wide-input direct current inverter topology comprises a two-transistor Buck-Boost inverter and an interleaved two-transistor Buck-Boost inverter. The feedforward average current control method applicable to the wide-input direct current inverter topology is composed of an input voltage feedforward module, a mode switching module, a voltage outer ring and a current inner ring. According to the method, input voltage feedforward is introduced into the current inner ring in average current control, a feedforward function from the input voltage feedforward to the current inner ring is computed, simplification is carried out, thereby obtaining feedforward average current control applicable to practical application, and the input dynamic response performance of the inverters in a whole input voltage range is greatly improved; and moreover, by adoption of an interleaving technology, the conversion capacity is increased, the output current ripple is effectively reduced, and the support is provided for the field with wide range input and high power conversion.

A method of controlling a brushless motor that includes rectifying an alternating voltage to provide a rectified voltage having a ripple of at least 50%, exciting a winding of the motor with the rectified voltage, and performing a first process or a second process in response to current in the winding exceeding a threshold that is proportional to the rectified voltage. The first process includes freewheeling the winding, while the second process includes continuing to excite the winding for an overrun period and freewheeling the winding at the end of the overrun period. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

The invention relates to a method for measuring grounding resistance of power transmission tower and a corresponding measurer, which are used for solving the problems present in the prior measurement such as inconvenient line arrangement and measurement interference. The method comprises the following steps of: (1) well connecting a lightning wire with a tower to be measured; (2) completely disconnecting the connection between a tower body of the tower to be measured and a ground net; (3) connecting grounding leads of the tower to be measured in parallel; (4) connecting a tower grounding resistance measuring instrument between the tower body and the leads; (5) resetting the instrument and executing measurement; and (6) reading the measured value. The measurer comprises a singlechip system, a keypad / display interface, a D / A converter, a V / I converter and a power amplifier circuit, an output current and ripple current sampling circuit, an A / D converter, a power supply system and a power voltage monitor and reset circuit. The invention has the advantages of convenient measurement and more accurate measurement by obviating power frequency interference and interference resulting from mutual interference effect in conventional method.

The invention provides a method for eliminating chopping waves and ripple waves and an analogue-digital conversion circuit for realizing the method. The method comprises the following steps of: carrying out two times of sampling on signals in a chopping wave period at an interval which is one half of time of the chopping wave period; and carrying out integration and summation on two times of sampling values so as to keep useful signals and eliminate residual ripple wave signals in the chopping waves. The signal amplification and analogue-digital conversion circuit comprises a chopping wave amplifier and a sigma-delta analogue-digital converter which is cascaded behind the chopping wave amplifier. A switching structure which is embedded into the sigma-delta analogue-digital converter is adopted and an analogue addition function of a first-grade integrator in the analogue-digital converter can be used for carrying out first-order reshaping (voltage summation) on the residual ripple waves of output signals of the chopping wave amplifier, so that the ripple wave amplitude is reduced and influences on the conversion precision of the analogue-digital converter is weakened. The circuit does not need an analogue low-pass filter between the chopping wave amplifier and the analogue-digital converter, so that the power consumption and the area are saved and the design of the circuit is simplified.

The invention discloses a non-flux observation doubly-fed induction generator low voltage ride-through control method and a system, which can be applied to excitation control on a rotor-side converter of the doubly-fed induction generator in the case of deep power grid fault. The specific implementation method comprises steps: once deep fault is detected to happen to the power grid, rotor current of the doubly-fed induction generator is instantly controlled to directly track stator current at a certain ratio, and a certain compensation term related to stator voltage is injected to a rotor current instruction for providing dynamic reactive support. The invention also provides a control system structure diagram for realizing the above principle. Compared with de-excitation control, flux tracking and other low voltage ride-through excitation control methods, no flux observation step is needed for generating a transient control instruction, the structure is simple, multiple control objectives such as electromagnetic torque ripple suppression or dynamic reactive power compensation can be realized, and the low voltage ride-through ability of the doubly-fed induction generator is greatly enhanced.

The invention discloses a novel aging technology of a mesohigh voltage aluminum electrolytic capacitor. The novel aging technology adopts an aging mode of adding alternating current and the direct current and comprises the following steps that: 10+ / -0.5 V alternating-current voltage can be applied for the preaging of a cathode first, the aging time can be 9-11 min, direct-current pulse current can be then applied for two anode and cathode ends of the capacitor for the direct-current pulse aging, the direct-current pulse aging can be subjected to section processing by a 12-stage power supply, wherein 1-8 stages of the power supply are used for normal-temperature aging, 9-12 stages of the power supply are used for high-temperature and constant-voltage aging, the direct-current pulse aging time is totally to be 180+ / -5 min, the aging voltage value of the eighth stage is set to be 1.15-1.2 times than that of the rated voltage of the capacitor, the aging temperatures for the high-temperature and constant-voltage of the 9-12 stages are set to be 105+ / -2 DEG C, and the aging voltage set value and the aging voltage value of the eighth stage are the same. By adopting the aging mode by adding the alternating current and the direct current, the effect of simultaneously repairing an anode oxidation film and a cathode oxidation film is reached, the problem that a whole energy-saving lamp is easily broken when an upper line of the energy-saving lamp is aged, the leakage of electricity of a product is reduced, the heat emission of the whole energy-saving lamp is reduced under a high-frequency condition, the ability of adapting to a high ripple wave of the aluminum electrolytic capacitor can be increased , and the reliability of the product is increased.

An adaptive pulse width control power conversion device includes a pulse width adjustable pulse frequency module (PFM) control circuit, a pulse width modulation (PWM) control circuit, a PWM / PFM switching unit, a switching circuit, and a load status detection circuit. When the power conversion device is to be switched from a PWM mode to a PFM mode, pulse width of a series of PFM control signals is sequentially adjusted from a low value to a high value according to a predetermined pulse width increment until an optimum pulse width is determined and thereafter, an output voltage is supplied to a load in the PFM mode, whereby ripple of output voltage in the PFM mode can be improved and improved stability of output of the power conversion device is realized.