32results about How to "Reduce output ripple" patented technology

The present invention provides a resonant converter. The resonant converter includes a first resonant conversion circuit, a second resonant conversion circuit, and a control unit. The first resonant conversion circuit has a first switch element and a second switch element, and the first switch element is ungrounded coupled to the second switch element and the second switch element is grounded. Thesecond resonant conversion circuit has a third switch element and a fourth switch element, and the third switch element is ungrounded coupled to the fourth switch element and the fourth switch element is grounded. The control unit receives a feedback signal and controls the first resonant conversion circuit and the second resonant conversion circuit according to the feedback signal. Accordingly,it is to simplify circuit controls and increase the dynamic performance of phase controls.

The rotary detector according to this invention comprises a rotary detector unit C1, C1' which detects rotary motion of a rotor; and a rotary calculator unit C2, C2' , C2" comprising a rotation angle detector, which detects the rotation angle of the rotor, and an angle speed detector 47 which detects the angle speed of the rotor, based on the output of the rotary detector unit. The rotary calculator unit comprises a trigonometrical calculator C3, C3', C3" which calculates a sine value or a cosine value of the rotation angle detected by the rotary detector; a gain adjuster 57, 57', 57" which multiplies the sine value or the cosine value, calculated by the trigonometrical calculator, by a predetermined gain; a multiplier 59, 59' which multiplies the output of the gain adjuster by the output of the angle speed detector; and a subtracter 61, 61' which subtracts the output of the multiplier from the output of the angle speed detector.

Disclosed is a control circuit for a buck-boost power converter. The control circuit is used for providing a control signal to drive a buck-boost power level so as to convert an input voltage into an output voltage. The buck-boost power level comprises an inductor and at least two switches connected with the inductor. The control circuit is characterized by comprising a feedback circuit, an error amplifier, a dynamic working period generator and a driving circuit, wherein the feedback circuit detects the output voltage to generate a feedback signal, the error amplifier is connected with the feedback circuit and amplifies a difference value between the feedback signal and a reference voltage to generate an error signal, the dynamic working period generator generates a first signal according to a detection signal after being started, and the driving circuit is connected with the error amplifier and the dynamic working period generator and determines the control signal according to the error signal and the first signal. The control circuit and method for the buck-boost power converter have the advantages that the on-off switching sequence is optimized, switching losses are reduced, efficiency is improved, and output ripples are reduced.

The present invention proposes a switching controller of a flyback power converter. The switching controller includes a switching circuit, a sample-and-hold circuit, a voltage detection circuit, an oscillation circuit, and a comparator. The voltage detection circuit generates a holding signal when a level of an input voltage of the flyback power converter is lower than a low-threshold. The oscillation circuit limits the maximum frequency of switching signal. The maximum frequency is increased in response to a decrement of a modulation signal. The modulation signal correlated with a level of the input voltage is used to generate a control signal when the level of the input voltage is lower than an ultra-low-threshold. The control signal is enabled to operate the flyback power converter in continuous current mode operation. Therefore, an input capacitor can be eliminated and manufacturing cost is saved.

The invention provides a bionic type piezoelectric pump. The bionic type piezoelectric pump comprises an upper sealing piece, a lower sealing piece, a cavity, a water inlet hose, a water outlet hose, a flexible piezoelectric driving piece B and a flexible piezoelectric driving piece A. A counter bore A, a water inlet and a water outlet are formed in the upper sealing piece. The water inlet is provided with a valvula valve A, and the water outlet is provided with a valvula valve C. The cavity is provided with a pump cavity, a water inlet connecting pipe, a water outlet connecting pipe, a water inlet water-collection hole and a water outlet water-collection hole. A one-way flowing valvula valve B is arranged in the pump cavity. The counter bore A corresponds to the pump cavity in position and is used for storing the flexible piezoelectric driving piece A. The lower sealing piece is provided with a counter bore B. The counter bore B is used for mounting and bonding the flexible piezoelectric driving piece B therein. According to the bionic type piezoelectric pump, a double-cavity double-vibrator structure is adopted; the pump cavity, the inlet and the outlet are provided with the valvula valves; the heart of a human body is simulated; and the bionic type piezoelectric pump is provided with the multiple pump cavities and the multiple valvula valves, and the capacity and pressure of the pump can be effectively increased. New reference is provided for research of an artificial heart.

Disclosed is a control circuit for a buck-boost power converter. The control circuit is used for providing a control signal to drive a buck-boost power level so as to convert an input voltage into an output voltage. The buck-boost power level comprises an inductor and at least two switches connected with the inductor. The control circuit is characterized by comprising a feedback circuit, an error amplifier, a dynamic working period generator and a driving circuit, wherein the feedback circuit detects the output voltage to generate a feedback signal, the error amplifier is connected with the feedback circuit and amplifies a difference value between the feedback signal and a reference voltage to generate an error signal, the dynamic working period generator generates a first signal according to a detection signal after being started, and the driving circuit is connected with the error amplifier and the dynamic working period generator and determines the control signal according to the error signal and the first signal. The control circuit and method for the buck-boost power converter have the advantages that the on-off switching sequence is optimized, switching losses are reduced, efficiency is improved, and output ripples are reduced.

The present invention relates to micro mechanical reciprocating membrane pump, and is one kind of micro mechanical reciprocating membrane pump for biochemical microanalysis. The micro mechanical reciprocating membrane pump has piezoelectric driving device as driving source, which makes the membrane vibrate to force the pump cavity to suck in and pump out fluid reciprocally; inertial fairing flow channel as no-motion valve to make the flow damp in some direction greater than that in the other direction; inertial ring cavity to further increase the damp difference between two directions. The present invention has simple structure, can drive fluid containing relatively large grain, has no damage to cell or macro molecule in fluid, no dead volume and constant flow rate and other advantages, and is suitable for driving micro volume fluid in micro flow channel of cross section size in decades and hundreds microns.

The invention relates to a control circuit for a buck-boost power supply converter, which is used for providing a control signal to drive a buck-boost power level, so that input voltage is converted into output voltage, wherein the buck-boost power level comprises an inductor and at least two switches connected to the inductor. The control circuit is characterized by comprising a feedback circuit, an error amplifier, a dynamic work period generator and a driving circuit, wherein the feedback circuit detects the output voltage and generates a feedback signal; the error amplifier is connected with the feedback circuit and amplifies a difference value between the feedback signal and reference voltage to generate an error signal; the dynamic work period generator generates a first signal according to a detection signal after being started; and the driving circuit is connected with the error amplifier and the dynamic work period generator, and determines a control signal according to the error signal and the first signal. The control circuit and a control method for the buck-boost power supply converter have the advantages that: a switch witching order is optimized; the switching loss is reduced; the efficiency is improved; and output ripples are reduced.

The invention relates to a buck-boost DC converter which can achieve a characteristic of zero-ripple voltage, wherein the zero-ripple voltage represents extremely low ripple voltage close to zero in engineering. The buck-boost DC converter comprises a ripple elimination inductor, an electric energy isolation and conversion unit, a power switch, a first inductor, a first capacitor, a second capacitor and a rectifying element, wherein the electric energy isolation and conversion unit is electrically connected to the ripple elimination inductor and comprises a plurality of coils, and the coils divide the buck-boost DC converter into an input stage and an output stage; the power switch, the first inductor and the first capacitor are located at the input stage and electrically connected to the electric energy isolation and conversion unit and the second capacitor and the rectifying element are located at the output stage and electrically connected to the electric energy isolation and conversion unit.

The invention relates to a novel interleaved parallel BUCK converter and a ripple elimination method thereof. The converter includes: 2n+2 IGBTs, n+1 inductors and two capacitors; n is a natural number; two IGBTs and an inductor form a phase bridge arm, and the converter has n+1 phase bridge arms in total; Wherein, the bridge arm of the second phase to the n+1th phase bridge arm are connected in parallel, and the bridge arm after parallel connection is directly connected to the capacitor C P connected in parallel, capacitor C S Inductor L connected in series with the first phase bridge arm S and capacitor C P Between; the first phase bridge arm is used as an output ripple compensation bridge arm, and the second phase bridge arm to the n+1th phase bridge arm are all used as power bridge arms for power transmission. The invention can reduce the switching loss, cost and volume of the interleaved parallel BUCK converter.