17results about How to "Small pulsation" patented technology

The utility model relates to three screw rod pump technical field, concretely relates to three screw rod pump for conveying high temperature lubricating grease, including double -deck heat preservation pump body, shaft seal, screw rod to be used for double -deck heat preservation pump body's double -deck welding type heat preservation mechanism, be used for shaft seal's mechanical seal flushing mechanism, be used for screw rod's axial thrust mechanism. The three screw rod pump for conveying high temperature lubricating grease, through having the double -deck welding type with heat preservation function's double -deck heat preservation pump body design, make it in the conveying high temperature lubricating grease pumping process, realize high pressure material in low pressure chamber when in overpressure is introduced, through having the shaft seal design with mechanical seal flushing system, reliably realized the shaft seal problem of high temperature lubricating grease, through the combination use under double -deck welding type heat preservation mechanism, mechanical seal flushing mechanism, axial thrust mechanism, can completely realize the safe long -life pumping of high temperature lubricating grease, pulsation is low, no shear, and this method is simple, economic, continuous, is suitable for the conveying process of high temperature lubricating grease.

In order to improve the stability of an existing exciter, a three-phase input winding is arranged on a stator and is connected with a three-phase power supply, a rotor is coaxially connected with a main generator, and meanwhile, a multi-phase output winding is arranged on the rotor and is connected with the input end of a rotating rectifier; the rotor is driven by a prime motor to rotate, and the rotating direction of the rotor is opposite to the rotating magnetic field direction of the stator. When the phase-changing power supply rotor is driven by a prime motor, a rotor winding cuts a stator rotating magnetic field with double fundamental frequency, multi-phase double fundamental frequency induced electromotive force is generated in the rotor winding, and power is supplied to a main generator exciting winding after rectification. The function of converting a three-phase power supply into a multi-phase power supply and then rectifying the multi-phase power supply into a direct-current excitation power supply is achieved, the reliability is high, and brushless can be achieved.

A pedestrian conveyor includes a torsional vibration damper system including a shaft, a cylindrical housing attached to the shaft and configured to damp vibrations of the shaft, a first gear, and a second gear.

The method and verification device for dynamic shock wave closed-loop control disclosed in the present invention at least partially solve the technical problems of unstable operation such as shock wave pulsation in the inlet of the existing engine. Based on the real-time control of the dynamic shock wave induced by the dynamic shock wave generator by the arc plasma exciter, the verification device sequentially arranges the plasma exciter and the dynamic shock wave generator along the airflow direction, and a first pressure sensor is installed at the upstream position of the plasma exciter, and a second pressure sensor is installed at a preset position downstream of the rotating shaft of the shock wave generator along the airflow direction; the current shock wave intensity is determined by obtaining the measurement values ​​of the first sensor and the second sensor, and the closed-loop controller monitors the switch state quantity of the plasma exciter and the theoretical value of the shock wave intensity in real time; according to the currently measured shock wave intensity, a closed-loop control is formed and the working parameters of the plasma exciter are adjusted in real time to achieve the stable control of the dynamic shock wave pressure ratio and achieve the preset control target value.

The present application discloses a horizontal flow metering pump, comprising a pump body, a crankshaft, a half-stroke plunger and a full-stroke plunger; a half-stroke cavity and a full-stroke cavity are arranged on the pump body, the half-stroke plunger and the full-stroke plunger are both slidably mounted on the pump body, one end of the half-stroke plunger is located in the half-stroke cavity, and the full-stroke plunger is located in the full-stroke cavity; the present invention has the following beneficial effects: by making the flow peak phases of the full-stroke pump cavity and the half-stroke pump cavity 180 degrees to each other, the pulsation is greatly reduced after superposition, and the flow is stable; and during the liquid suction process of the half-stroke pump cavity, the half-stroke plunger will generate a reverse thrust acting on the crankshaft, which assists the liquid discharge process of the full-stroke plunger pump head and reduces energy consumption.

The application discloses a Sepic type power correction circuit based on a switched inductor, which comprises switching tubes S1-S3, diodes D1-D5, inductors L1-L5, capacitors C1 and C o The diodes D3-D5 and the inductors L4 and L5 form a switched inductor structure, and the voltage gain of the converter is D / (2-D). Compared with a conventional Sepic PFC converter, the Sepic type power correction circuit based on the switched inductor improves the step-down gain, ensures that the whole duty cycle range is in a step-down state, and has a larger duty cycle than the conventional Sepic PFC converter in the case of a high step-down ratio, thereby effectively avoiding the emergence of a limit duty cycle. The no-bridge structure can realize lower conduction loss. The original output diode is replaced by the switched inductor structure, so that the output current is continuous, and the output current can be filtered. All the switching tubes are common ground, and a lower-cost driving circuit can be used.

A current decoupling control method for an auxiliary inductor dual-buck half-bridge power amplifier relates to the field of precision motor drive. The present invention controls the magnitude of the average current flowing through the auxiliary inductor to balance the current passing through the filter inductors on the two branches, thereby reducing the output current pulsation and further reducing the loss. The magnitudes of the currents in the two branches are set to constant values, so that the two branch currents output a half-cycle sine wave, and the branch output current does not pass through the zero point, thereby reducing the switching loss and harmonic distortion. The topological method of auxiliary increase in inductance can reduce the total inductance volume of the loop, and improve the problem of large inductance volume and weight caused by the DC bias magnetization of the inductor caused by the bias current. In addition, the auxiliary inductor current is added to the bias current of the loop, thereby reducing the nonlinear distortion of the system. The present invention improves the disadvantage of large inductance volume in the traditional dual-buck half-bridge inverter circuit loop, reduces the cost, and reduces the harmonic distortion of the circuit.

The invention discloses a method for suppressing rotation speed pulsation of a permanent magnet synchronous motor caused by a current measurement error. Acquiring state data of the permanent magnet synchronous motor; according to the acquired state data, based on a given signal and an actual three-phase current signal of the permanent magnet synchronous motor, determining a PWM wave signal for controlling the operation of the permanent magnet synchronous motor; according to the determined PWM wave signal and the constructed permanent magnet synchronous motor mathematical model; then, by optimizing a control strategy, such as a vector control method, the rotating speed of the motor can be adjusted more accurately, and pulsation caused by current measurement errors is reduced; and finally, by applying a filtering algorithm on a current measurement value, noise and interference from the sensor can be reduced, so that the measurement precision is improved. By adopting a filtering algorithm, adjustment and optimization can be carried out according to specific application and requirements so as to realize effective filtering and smooth processing of signals, thereby reducing noise and interference from the sensor and improving measurement precision.

The application discloses a bridgeless Cuk PFC converter based on a switched-inductor-capacitor structure, which comprises switching tubes S1-S3, diodes D1-D4, inductors L1-L5, capacitors C1, C2 and C o The diodes D3 and D4, the capacitor C2 and the inductors L3 and L4 form a switched-inductor-capacitor structure. The original freewheeling diode is replaced by the switched-inductor-capacitor structure, so that the voltage gain of the converter is D / 2(1-D), compared with a traditional Cuk PFC converter, the converter realizes positive voltage output and improves the voltage reduction gain, and the duty cycle range in the voltage reduction mode is wider. Meanwhile, the bridgeless structure is adopted, so that lower on-state loss can be realized. The converter has continuous input and output currents, high power factor and high efficiency, and has rich application.

The invention relates to a maintenance method of an inner curve hydraulic motor cam ring, which comprises the following steps of: scanning point coordinates of an original cam ring curve, and calculating a motion equation of the center of a roller according to the point scanning coordinates of the cam ring and the radius of the roller by using software; and then, according to the new small diameter of the cam ring and the roller center motion equation, calculating the curve point coordinates of the cam ring after maintenance. According to the cam ring maintained by the method, the original design movement rule of the original motor is not changed under the condition that the curve design principle of the original cam ring is not known, and the stable operation of the maintained motor is ensured. Meanwhile, the machining error of an original curve can be compensated by using the method to repair the cam ring, and the pulsatility of the repaired motor is even possibly lower than the pulsatility of the original curve.

This invention discloses an exhaust muffler assembly, a compressor, and a refrigeration appliance, relating to the field of compressor technology. It solves the problem of poor noise reduction effect of existing exhaust mufflers and improves the ability and effect of reducing exhaust noise and pulsation. The specific solution is as follows: the axis of the air inlet is perpendicular to that of the exhaust outlet. A first inner tube is fixedly installed at one end of the first exhaust pipe and passes through the air inlet and is inserted into the muffler mechanism. The end connection between the first inner tube and the first exhaust pipe is a constricted section with a size smaller than the diameter of the first exhaust pipe. The outlet end of the first inner tube faces away from the exhaust outlet. A buffer platform for buffering airflow is fixedly provided on the side wall of the muffler mechanism adjacent to the outlet end of the first inner tube.

This invention relates to the field of reciprocating pump technology, specifically to a low-pulse steady-flow reciprocating pump. The reciprocating pump includes a pump body, a gearbox, and a pump head, with the gearbox and pump head respectively located at both ends of the pump body. The reciprocating pump includes a cylindrical cam reciprocating mechanism and a protection mechanism. The cylindrical cam reciprocating mechanism reduces the pulsation of the reciprocating pump, achieving uniform and stable flow delivery. The protection mechanism works in conjunction with the cylindrical cam reciprocating mechanism to cool the pump body. This invention utilizes a differential mechanism in conjunction with the cylindrical cam reciprocating mechanism. The specially designed cylindrical cam in the cylindrical cam reciprocating mechanism reduces the pulsation of the reciprocating pump, achieving uniform and stable flow delivery. Furthermore, the structure is simple and compact, occupying little space. The rotational connection between the limiting roller and the slide bar allows the limiting roller to roll along the cylindrical cam during reciprocating motion, reducing the friction between the cylindrical cam and the limiting roller, thereby reducing wear and extending their service life.

The invention discloses a high-gain bipolar grid-connected inverter applied to a photovoltaic hydrogen production system, which comprises a first transformer, a second transformer, a two-phase staggered inversion unit, a three-level rectifying unit and a half-bridge inverter, and is characterized in that primary coils of the first transformer and the second transformer are connected in parallel, and secondary coils of the first transformer and the second transformer are connected in series in opposite directions; the two-phase interlaced inversion unit is used for interlacing and connecting a photovoltaic power supply with primary coils of the first transformer and the second transformer in parallel and complementing current ripples of direct current output by the photovoltaic power supply; the three-level rectifying unit is used for boosting the voltage of the alternating current output by the first transformer and the second transformer and converting the alternating current with the boosted voltage into direct current with a bipolar characteristic to be output; and the half-bridge inverter is used for converting the direct current output by the three-level rectifying unit into alternating current and outputting the alternating current to a hydrogen production power grid. According to the invention, leakage current can be suppressed, the cost is low, the size is small, and three-level output is realized.

The application discloses a kind of liquid piston pump systems and working methods of multiple hydraulic cylinder phase difference arrangement, including drive motor, transmission mechanism, first hydraulic cylinder unit, flow convergence pipeline, high-pressure liquid outlet main pipeline and low-pressure liquid inlet main pipeline.First hydraulic cylinder unit includes first hydraulic cylinder and second hydraulic cylinder, two pistons movement phase difference half movement cycle, so that two hydraulic cylinders alternate execution liquid suction and liquid discharge stroke.System further includes at least one same structure hydraulic cylinder unit, each unit is arranged according to preset phase difference, and the output fluid is converged and output after passing through flow convergence pipeline.The application is arranged by pure mechanical structure phase difference, without sensor and controller, can effectively inhibit output flow pulsation, with the advantages of simple structure, high reliability, low cost.

This invention relates to a pulsation reduction device installed in a vehicle's hydraulic braking system. The pulsation reduction device includes: a first chamber (A) into which brake hydraulic fluid is input from a brake hydraulic circuit (2); a second chamber (B) into which brake hydraulic fluid is output to the brake hydraulic circuit (2); and a connecting portion (80a) connecting the first chamber (A) and the second chamber (B); the connecting portion (80a) includes: a first valve body (86) movable to a non-connected position seated on a first valve seat (85b) without connecting the first chamber (A) and the second chamber (B), and a connected position dismounted from the first valve seat (85b) and connecting the first chamber (A) and the second chamber (B); and a force-applying member for applying force to the first valve body (86) towards the first valve seat (85b). b) Lateral force application; the force application components include a second force application component (89) and a third force application component (90) different from the second force application component (89); the second force application component (89) has a hysteresis characteristic that the recovery force (p) in the loading process and the recovery force (p) in the unloading process are different magnitudes when the displacement (s) is the same in the loading process and the unloading process; the third force application component (90) has a characteristic that the recovery force (p) in the unloading process when the displacement (s) is the same as that of the second force application component (89) is larger than the recovery force in the unloading process of the second force application component (89) when the displacement (s) is the same.

The application provides a kind of weak magnetic control method based on permanent magnet synchronous motor adaptive parameter identification, it is related to motor control technical field, the method is by fusing the improved particle swarm optimization algorithm (CIPSO) of chaos inertia weight and Gaussian disturbance online identification stator resistance, cross-axis inductance and permanent magnet flux linkage, solve the problem of control performance decline caused by parameter time-varying;Below rated speed, maximum torque current ratio (MTPA) control based on real-time parameters is used, the convex pole effect is used to reduce the amplitude of stator current, improve the efficiency and dynamic response of low speed operation;Above rated speed, the voltage saturation criterion triggers the lead angle weak magnetic control, dynamically introduces the phase of lead angle correction current vector, makes the operating point move along the voltage limit ellipse boundary, breaks through the voltage constraint of inverter, while combining the parameter identification result carries out feedforward decoupling compensation, realizes the smooth switching from MTPA to weak magnetic and high speed area stable operation.

The application discloses a Cuk type power factor correction circuit based on a switching inductor, which comprises switching tubes S1-S3, diodes D1-D5, inductors L1-L5, capacitors C1 and C o Among them, diodes D3-D5 and inductors L3 and L4 form a switching inductor structure.The converter voltage gain is D / (2-D), compared with a traditional Cuk PFC converter, the power factor correction circuit realizes positive voltage output, improves the step-down gain, ensures that the whole duty cycle range is in a step-down state, and the duty cycle is larger than that of the traditional Cuk PFC converter in the case of high step-down ratio, and the emergence of the limit duty cycle condition is effectively avoided.The application of the bridgeless structure can realize lower on-state loss.The power factor correction circuit has the advantages of continuous input and output current, high power factor and high efficiency, and has great practical value.