2047 results about "Ripple" patented technology

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 V_IN 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.

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.

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.

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.

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 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.

The invention discloses a ripple reducing circuit for a light-load pulse hopping mode of a DC-DC (Direct Current-Direct Current) converter, which mainly solves the problem that the output ripple of an existing light-load pulse hopping mode is large. The ripple reducing circuit comprises a capacitance charge-discharge unit (1), a comparison unit (2), a logic control unit (3) and a switch-on time control unit (4), wherein the capacitance charge-discharge unit (1) is used for outputting different voltage signals VC1 according to difference of switch-off signals ZC of a switch tube; the comparison unit (2) is used for comparing the voltages signals with reference voltage and supplying a zero clearing signal to the logic control unit (3); the logic control unit (3) is used for counting a pulse signal LG and outputting a switch signal RR; the switch-on time of an upper switch tube can be controlled by the switch signal through controlling the size of charge current of internal capacitance of the switch-on time control unit (4), and a peak value of inductive current can be reduced. According to the ripple reducing circuit disclosed by the invention, the output voltage ripple of the light-load pulse hopping mode of the converter is effectively reduced while the high efficiency of the converter is ensured, and the ripple reducing circuit can be used for the DC-DC converter.

The invention discloses a feedback circuit of a negative-pressure charge pump. The feedback circuit is connected between the output end of the negative-pressure charge pump and an AND gate, and a clock signal is connected with the negative-pressure charge pump through the AND gate under the control of feedback signals. The feedback circuit comprises a switch capacitor circuit and a comparator, the first end of a first capacitor of the switch capacitor circuit is connected with the output end of the negative-pressure charge pump through a first switch and is grounded through a second switch, the first end of a second capacitor is connected with the second end of the first capacitor, is grounded through a third switch and is connected with the comparator through a fourth switch, an adjustable capacitor is connected parallelly in two ends of the second capacitor, and a positive phase input end of the comparator is connected with reference voltage. The four switches are controlled through four control signals, so that the switch capacitor circuit can be switched between two states successively, and conversion between the division voltage and positive and negative voltage is realized. By the feedback circuit, the area of the circuit can be reduced, feedback is accelerated and output voltage ripples of the charge pump can be reduced.

A ripple current generation method adopts a direct current power supply U, an inductor L, a transformer T with two windings wound in a bifilar mode, a diode D, a field effect tube Q, a pulse width modulation control circuit P and a tested capacitor, wherein the transformer T is provided with a magnetic core with an adjustable air gap, and the tested capacitor and the inductor L are connected in series and then are in parallel connection with the power supply. The field effect tube Q and the winding 1 of the transformer T are connected in series and then are in parallel connection with the tested capacitor. The winding 2 of the transformer T and the diode D are connected in series and then are in parallel connection with the tested capacitor. The control circuit P drives the field effect tube Q to work in an on-off state, and the biggest duty ratio is smaller than 0.5. When the Q is turned on, the winding 1 is excited to produce discharge current, and when the Q is turned off, the winding 1 carries follow current and performs demagnetization to produce charging current, and energy is recovered. Therefore, ripple current of the tested capacitor is obtained, and a ripple current generation circuit has the advantages of being low in cost, low in energy consumption, simple in wiring and small in size.

The invention discloses an electron beam welding machine power supply high-voltage voltage stabilization method and method employing a micro ripper Cuk type converter. The method comprises the following steps: (1), after a three-phase AC power supply is subjected to boosting, rectification and filtering, high voltage is obtained; (2), the high voltage passes through a DC converter, an on-off duty ratio is controlled for adjusting output voltage; (3), the output voltage passes through a PID circuit and a PWM circuit, the duty ratio of a power device is controlled, and the size of the output voltage can be adjusted; and (4), needed voltage is obtained at an output capacitor. The apparatus further comprises a boost rectification filtering circuit, a Cuk main circuit, a control circuit and an output circuit. According to the invention, the Cuk main circuit is introduced in a switch power supply circuit, two inductors of the Cuk circuit are coupled by use of the property of the coupling inductors, the coupling degree of the inductors is reasonably distributed, the circuit ripples are substantially reduced, a feedforward circuit is additionally arranged to enable fluctuations generated at an input end to be directly adjusted from the input end, the control adjustment speed of a whole power supply system is enabled to be higher and more stable, the structure is simple, the control is easy, and the cost is low.

A power supply for converting AC to a regulated DC output current, utilizing two serial switched mode power supplies, the first providing an intermediate DC output voltage with only moderate ripple properties, this output being input to the second, which operates as a DC/DC converter to provide the desired output with low ripple and good regulation. The diode rectifier assembly has no reservoir/smoothing capacitor, or one of much smaller capacitance than in prior art power supplies. The large resulting rectifier output ripple is overcome by use of the two power supply units, at least the first having a smoothing capacitor at its output. A majority of the energy stored in this capacitor is utilized during each AC half cycle. Such power supplies also provide improved hold-up times. The power supply is also constructed to have low standby power consumption, by use of a double burst configuration.

The invention discloses a power factor correcting and converting method and device for eliminating power frequency ripple waves by peak load shifting. An extra bidirectional DC/DC (Direct Current/Direct Current) converter is combined with an AC/DC (Alternating Current/Direct Current) single-phase PFC (Power Factor Correction) converter; when an output of the single-phase PFC converter is higher than a reference voltage or a reference current, the bidirectional DC/DC converter is used for storing and absorbing surplus energy to an energy buffering and storing capacitor; when the output of the single-phase PFC converter is lower than the reference voltage or the reference current, the energy of the energy storage capacitor is released to a load; and alternating current ripple wave energy output by the single-phase PFC converter is compensated by the way so that double power frequency ripple waves on a filter at a direct current output end of the single-phase PFC converter are eliminated. According to the method and the device provided by the invention, a power frequency ripple wave voltage or a ripple wave current of a power factor correction converter is eliminated, and the following problems are solved: the cost is high due to utilizing a large-capacity capacitor to reduce the power frequency ripple waves of the power factor correction converter, the efficiency is low due to using a cascaded two-stage converter, and the like.

A combined type DC-DC (direct current) converter is composed of two DC power supplies (1) connected in series and two completely symmetrical boosted modules (2 and 3). The combined type DC-DC converter is used for converting lower voltage of a renewable DC source such as a photovoltaic /fuel cell and the like to higher voltage for outputting. Compared with the existing boosted converter, the combined type DC-DC converter provided by the invention has a larger boosted transformation ratio under the condition of the same duty cycle, the voltage current stress of a switching tube is low, ripple of input current is low and ripple of output voltage is low; meanwhile, the combined type DC-DC converter has the outstanding advantages of simple structure and convenience in control and the like, and is very applicable to the grid-connected system of renewable energy sources such as photovoltaic /fuel cells and the like in the future, thus the combined type DC-DC converter has better applicationand promotion prospects.