32results about How to "Solve uneven flow" patented technology

The invention provides a current non-equalizing control method of a converter multi-unit parallel system. The phenomenon of current non-equalizing during converter multi-unit parallel connection is avoided by delaying a falling edge of a control pulse, namely delaying switch-off. When a certain phase of current of a certain converter is low, the aim of increasing the phase of current is fulfilled by delaying the falling edge of the phase of control pulse. When n three-phase pulse width modulation (PWM) converters are connected in parallel, corresponding phases of (n-1) three-phase PWM converters are required to be compensated. The delay time of the falling edge of the control pulse is a current function. In order to achieve an online real-time dynamic compensation effect, a fixed delay time compensation method is employed, a current compensation effect is observed, and compensation time is continuously modified, so a relation curve of the compensation time and current is determined.

The invention discloses a three-phase coupling reactor and a converter. The three-phase coupling reactor comprises an iron core and six windings, the iron core comprises an upper iron yoke, a lower iron yoke, at least one first iron core post without a gas gap and three second iron core posts with gas gaps, wherein the first iron core post and the second iron core posts are located between the upper iron yoke and the lower iron yoke; two windings wind each second iron core post, and the ends of the two windings on the same second iron core post in different names are connected in a short circuit mode. According to the three-phase coupling reactor and converter, the zero sequence circulating current impedance of the converter system is increased through the coupling between windings, and accordingly the problem of uneven current of parallel power modules due to zero sequence circulating current is effectively solved.

The invention discloses a forging piece forming method based on differential temperature control. The method comprises the steps of placing a whole forging piece into a heating furnace, heating the forging piece to the temperature ranging from 600 DEG C to 800 DEG C, keeping the temperature for 2 hours to 3 hours, taking the forging piece out of the heating furnace, placing the forging piece inside a die cavity, warping a local low-temperature area by heat preservation cotton, placing the forging piece into the furnace again, and taking out the forging piece when the whole temperature of the forging piece is increased to range from 1000 DEG C to 1020 DEG C for forging, wherein at the moment, the temperature of the portion wrapped by the heat preservation cotton is 50 DEG C to 100 DEG C slightly lower than that of the other portions; placing a die forging piece forming device into the heating furnace, heating the die forging piece forming device to the temperature ranging from 200 DEG C to 250 DEG C, inserting a heating stick into a heating hole in an upper die insert, partially heating the die forging piece forming device to the temperature ranging from 350 DEG C to 400 DEG C, taking out the die forging piece forming device for forging, and utilizing the die forging piece forming device for forging and forming the forging piece. According to the forging piece forming method based on the differential temperature control, the forging piece forming filling rate is high, the service life of the die is long, grains of the forging piece are fine, the forming force of the die forging piece can be reduced to the great extent, and the service life of the hot-forging die is prolonged.

The invention discloses a multi-inverter parallel current equalization control method, which comprises four parts: multi-inverter parallel circuit, delay pulse width compensation, SPWM modulation and current equalization control. The circulating current problem existing in the parallel system is solved, and the uneven current problem of the output current of the inverter is solved by pulse delay compensation. The advantage of the pulse modulation method being the closed-loop compensation method is that it can realize automatic compensation and can adapt to the multi-inverter parallel system with different parallel numbers. Therefore, by changing the pulse modulation method to SPWM modulation method, the circulating current in the parallel system is effectively suppressed. question.

The invention discloses an interleaved parallel PFC control circuit for controlling parallel PFC circuits, wherein a sampling module samples alternating current input voltage, PFC bus voltage and PFC bus current; a processing module processes the sampling signals and a reference voltage signal to generate a control signal; a comparing module compares the control signal with a first carrier signaland a second carrier signal to generate a first duty ratio signal and a second duty ratio signal, wherein the first carrier signal and the second carrier signal are interleaved by a specified phase angle and have the same wave shape; and a selecting module alternates the first duty ratio signal and the second duty ratio signal respectively according to the period thereof to be used as the drivingcontrol signal of one of two parallel PFC circuits to another to be output. The invention also discloses an interleaved parallel PFC control method. The invention can effectively avoid the problem ofunbalanced current caused by asymmetrical driving signals of the prior interleaved parallel circuit, and has simple realization and low cost.

The invention discloses a forging piece forming method based on differential temperature control. The method comprises the steps of placing a whole forging piece into a heating furnace, heating the forging piece to the temperature ranging from 600 DEG C to 800 DEG C, keeping the temperature for 2 hours to 3 hours, taking the forging piece out of the heating furnace, placing the forging piece inside a die cavity, warping a local low-temperature area by heat preservation cotton, placing the forging piece into the furnace again, and taking out the forging piece when the whole temperature of the forging piece is increased to range from 1000 DEG C to 1020 DEG C for forging, wherein at the moment, the temperature of the portion wrapped by the heat preservation cotton is 50 DEG C to 100 DEG C slightly lower than that of the other portions; placing a die forging piece forming device into the heating furnace, heating the die forging piece forming device to the temperature ranging from 200 DEG C to 250 DEG C, inserting a heating stick into a heating hole in an upper die insert, partially heating the die forging piece forming device to the temperature ranging from 350 DEG C to 400 DEG C, taking out the die forging piece forming device for forging, and utilizing the die forging piece forming device for forging and forming the forging piece. According to the forging piece forming method based on the differential temperature control, the forging piece forming filling rate is high, the service life of the die is long, grains of the forging piece are fine, the forming force of the die forging piece can be reduced to the great extent, and the service life of the hot-forging die is prolonged.

The invention discloses a current sharing circuit structure with a large number of capacitors connected in parallel and a spheromak device power supply. According to the current sharing circuit structure, a single-group capacitor structure comprises a plurality of capacitors, a positive group connecting bar and a negative group connecting bar, the plurality of capacitors are connected in parallel, the positive electrodes of all the capacitors are connected to the positive group connecting bar, the positive group connecting bar is connected with the positive electrodes of all the capacitors and then leads out along a capacitor arrangement direction A, the negative electrodes of all the capacitors are connected to the negative group connecting bar, the negative group connecting bar is connected with the negative electrodes of all the capacitors and then leads out along a capacitor arrangement direction B, the wiring direction is changed to be along the capacitor arrangement direction A by rotating 180 degrees at the position of the last capacitor, the wiring direction and the outgoing line of the positive group connecting bar are gathered and led out to form a loop, and the direction A and the direction B are parallel and opposite; and multiple groups of capacitor structures comprise multiple groups of single-group capacitor structures, and the multiple groups of single-group capacitor structures are arranged side by side to form a capacitor group parallel matrix structure. According to the invention, the capacitor group parallel matrix structure can achieve the current sharing effect without adding extra devices.

The application discloses a linear stabilized voltage power supply, which includes a current sharing control circuit. The current sharing control circuit includes at least one current sharing control unit, and each current sharing control unit includes a driving voltage adjustment circuit, a linear voltage stabilization circuit and a feedback circuit. Wherein, the feedback circuit is used to feed back the voltage of the current sampling resistor of the linear voltage stabilizing circuit to the driving voltage adjusting circuit, and the driving voltage adjusting circuit adjusts the current of the analog control signal Vctrl input to the current sharing control unit according to the voltage value of the current sampling resistor before Output to the linear voltage stabilizing circuit, so as to adjust the output power of the linear voltage stabilizing circuit by adjusting the voltage of the current sampling resistor. Since the output power of the linear voltage stabilizing circuit of each current sharing control unit can be adjusted separately, the problem of uneven current of the linear voltage stabilizing power supply can be solved, so as to improve the stability and service life of the linear voltage stabilizing power supply.

The embodiment of the invention provides a battery system and an electric vehicle, and relates to the technical field of battery application. The battery system comprises at least two battery branchesand a controller, wherein each battery branch comprises a battery and a regulating unit, each battery branch is connected in parallel with each other, the battery in each battery branch is connectedin series with the regulating unit in each battery branch, and the controller is electrically connected with the regulating unit in each battery branch; The controller is used for regulating the resistance value of the regulating unit in each battery branch according to a pre-established mathematical model, thereby regulating the output current of each battery branch. The battery system and the electric vehicle provided by the embodiment of the invention can solve the problem that the output current distribution of each branch of the battery system is unbalanced.

The invention discloses a three-phase coupling reactor and a converter. The three-phase coupling reactor comprises an iron core and six windings, the iron core comprises an upper iron yoke, a lower iron yoke, at least one first iron core post without a gas gap and three second iron core posts with gas gaps, wherein the first iron core post and the second iron core posts are located between the upper iron yoke and the lower iron yoke; two windings wind each second iron core post, and the ends of the two windings on the same second iron core post in different names are connected in a short circuit mode. According to the three-phase coupling reactor and converter, the zero sequence circulating current impedance of the converter system is increased through the coupling between windings, and accordingly the problem of uneven current of parallel power modules due to zero sequence circulating current is effectively solved.

The invention discloses a test method, a test system and test equipment. The test method comprises the following steps: dividing source data into a plurality of groups, wherein the source data are used for testing a plurality of resources, and the source data that test the same resource are divided into the same group; generating grouping information based on the source data in the same group; generating a plurality of sequences based on the plurality of groups; and taking the grouping information and the plurality of sequences as configuration information, sending the configuration information to a plurality of terminals together with a test instruction, wherein the test instruction is used for instructing the plurality of terminals to test the plurality of resources according to different sequences in the plurality of sequences and according to the grouping information.

This invention relates to a micro-channel ribbon tube hot pump air-condition / exchanger composed of an upper collector, a lower collector, micro-channel ribbon tubes and ribs, which are plane or wave ones with drainage grooves distributed slantly against the wind to exhaust condensed water or frost water timely, in which a liquid separation structure is applied for the connection of upper and lower collectors with the micro-channel ribbon tubes to solve the problem that heat-exchange area can't be used fully since cooling agent can't flow uniformly among channels when the heat exchanger is used as an evaporator.

The invention provides a method for determining an oil outlet position of a double rectangular cavity static pressure sliding bearing; during the operation process of the static pressure sliding bearing, due to the influence of the position of the oil outlet, the shape and rotary speed of an oil chamber, the flow rate of the hydraulic oil flowing out of each oil sealing edge is different, so the operation stability of the static pressure equipment is reduced. In order to balance the flow of the oil sealing edge, reduce the influence of the rotary speed on the flow distribution and improve thebearing performance and stability of the static pressure sliding bearing, the invention provides the method for determining the oil outlet position of the double rectangular cavity static pressure sliding bearing. The method comprises the following steps of: step A: establishing a single rectangular cavity to simplify the flow rate vector; step B: establishing a rotary speed vector of a turntable,and synthesizing with the hydraulic oil flow rate vector to obtain a resultant velocity; step C: analyzing the flow change of each oil sealing edge by the resultant velocity, and performing integralsum calculation; step D: obtaining a liquid resistance ratio from the flow rate ratio, wherein the distance from the oil outlet to the oil sealing edge is larger, and calculating the coordinates of the oil outlet by the integral ratio method; and step E: calculating the position of the oil outlet of another oil chamber by the geometric method.

The invention discloses a parallel IGBT power unit. The parallel IGBT power unit comprises an upper bridge IGBT module and a lower bridge IGBT module. Each IGBT module includes at least two IGBT modules which are connected in parallel, and further comprises an upper busbar and a lower busbar which are correspondingly connected with the two IGBT modules. The upper busbar is provided with a first leading-out terminal for connecting with a first main busbar and a first capacitor connecting terminal for connecting with a capacitor. The lower busbar is provided with a second leading-out terminal for connecting with a second main busbar and a second capacitor connecting terminal for connecting with a capacitor. According to the parallel IGBT power unit, the two IGBT modules and the two busbars which have identical structures and are correspondingly connected with the modules respectively are adopted; the leading-out terminals for connecting with the main busbars and the capacitor connecting terminals for connecting with the capacitors on the busbars are in conductive connection with docking connecting terminals and capacitor connecting terminals at corresponding positions of the IGBT modules of corresponding busbars by using copper bars in identical lengths; and since busbars connecting the IGBTs are identical in length, the current-sharing performance of the parallel IGBT modules on the busbars is guaranteed, and a problem of uneven current during parallel connection of the IGBTs is solved.