61results about How to "Meet the requirements of control accuracy" patented technology

The invention discloses a rotary steering tool controlling method which can be used for determining the control mode and steering parameters of a steering tool, achieving automatic control over a hole trajectory, improving the working efficiency of the steering tool, and meeting the requirement of directional drilling for steering control. The method comprises the steps of acquiring surveying data and monitoring the trajectory. By the adoption of the method, steerable drilling efficiency is improved, hole trajectory control precision is improved, and the requirement of extended-reach well drilling, complicated geology structure horizontal well drilling and geosteering drilling for trajectory control can be met.

The invention relates to surveying and mapping class, in particular to a method for surveying river-crossing leveling during the shield run-through of rivers in tunnel engineering, which comprises the steps of: starting from various elevation control points of two banks of a river respectively, adopting a second-order leveling surveying specification, and inductively surveying elevations to the banks of the river respectively first; then taking second-order leveling points inductively surveyed on the two banks of the river as transfer station surveying points; and finally taking triangular elevation surveying as the basis, utilizing a higher electronic holographic device, staring from one transfer station surveying point on one side of the river to place a sighting target as 'backsight', placing a sighting target as 'foresight' at one transfer station surveying point on the other side of the river, and transferring the elevation of the 'backsight' sighting target to the 'foresight' sighting target by surveying through the station surveying points and taking the station surveying points as the transition. The method is simple, convenient and efficient, has simple used equipment and high surveying accuracy, is particularly suitable for the construction of the tunnel shield run-through of the rivers, and can effectively meet the requirement of control precision of run-through surveying of shield advance construction.

The invention discloses an energy-saving full-function refrigeration cycle system, which consists of an indoor unit and an outdoor unit, wherein the outdoor unit comprises a compressor, an outdoor heat exchanger, a heating expansion valve, a check valve, a heating dry filter, a liquid receiver, a vapor-liquid separator and a pipe joint; and the indoor unit comprises a blower, an electromagnet valve B, an electromagnetic valve A, a refrigerating dry filter, a refrigerating expansion valve B, a check valve B, an indoor heat exchanger B, a check valve A, a refrigerating expansion valve A, an indoor heat exchanger A, an electromagnetic valve C, and a four-way reversing valve. The refrigeration cycle system can meet the requirement of control precision defined by the national standard under the condition of energy-saving operation. The refrigeration cycle system can greatly save heating energy consumption through the energy-saving operation of partial working condition, improve the energy-efficiency ratio in a heating season and annual performance coefficient, and has important practical value.

The invention discloses a control method of a sight-stabilizing servo system based on ADRC and NLPID. Under the premise of meeting the control precision requirement of the sight-stabilizing servo system, through the design of applying an active disturbance rejection control algorithm to a speed loop controller of the servo control system, steady-state error of the sight-stabilizing servo system isreduced; and through the design of applying an improved non-linear PID control algorithm to a current loop controller, torque fluctuation of a DC torque motor can be suppressed effectively. The control method has obvious effect for improvement of tracking precision of the sight-stabilizing servo system and enhancement of disturbance isolation property, and meanwhile, the controller of the servo system has high adaptability and robustness.

The invention provides a combined type pressurizing double-electromagnetic-valve gas injection device which comprises a pressurizing part, a double-electromagnetic-valve part, a double-control-piston part, a double-needle-valve-nozzle part and an injection device body. The pressurizing part is located on the upper portion of the injection device body. The double-electromagnetic-valve part is located at the position, below the pressurizing part, in the injection device body. The double-control-piston part is located at the position, below the double-electromagnetic-valve part, in the injection device body. The double-needle-valve-nozzle part is located on the lower portion of the injection device body. The combined type pressurizing double-electromagnetic-valve gas injection device can be matched with an engine with a wide power range, and gas leakage and static control oil leakage are avoided. Two electromagnetic valves are adopted for controlling two nozzles to inject gas separately, the two nozzles share one pressurizing piston to achieve gas pressurization, and the gas injection process can be switched between a pressurizing mode and a non-pressurizing mode. The gas injection process and the gas pressurizing process are controlled separately, injection pressure can be adjusted, the injection law is flexible and changeable, and the needs for the power of the engine under different working conditions and the power of serialized engines are met.

The invention relates to a method for controlling the variable temperature and humidity interval of a central air conditioner. The method includes a temperature loop control method and a humidity loop control method. The temperature loop control method includes the steps that after a unit is operated, whether the current environment temperature is within the safety interval set in a program or not is judged; if the current environment temperature is within the safety interval, the temperature set value is in a change following state, and PID variables are triggered to be reset; thirdly, if the current environment temperature is not within the safety interval, the temperature set value is set to be the upper limit value regulated in the program when the current environment temperature is larger than values within the safety interval, PID trigger adjustment is conducted, and the temperature value is controlled towards the safety interval at the highest system speed; when the current environment temperature is smaller than the values within the safety interval, the temperature set value is set to be the lower limit value regulated in the program, PID trigger adjustment is conducted, and the temperature value is controlled towards the safety interval at the highest system speed. The process of the humidity loop control method is the same as that of the temperature loop control method. The method meets the maximal energy-saving space requirements.

The speed controller for the coiling apparatus possesses one PID calculation device for the PID calculation for the essentially identical frequency detecting value corresponding to the detected linear speed value of the speed sensor and the frequency command value corresponding to the given linear speed command value; and one PID calculating result correcting device to correct the PID calculating result and comprising a last frequency input unit, a subtraction calculation unit, a frequency dependence calculating unit, a limit unit and an addition calculation unit. The lower the motor rotation speed, the less the dependence of the PID calculating result on the output frequency. The corrected PID calculating result is used as the output frequency to the motor.

The invention discloses an energy storage-combined wind power plant energy management system, comprising an energy management module, a wind power plant booster station data collecting module which isconnected to the energy management module, an energy storage device data collecting module, a scheduling data receiving module, a wind turbine generator data collecting module, a storage module, a historical data query module, a wind turbine generator system control module, an energy storage device control module, and a monitoring alarm module connected to the storage module. The invention is advantageous in that active and reactive fluctuation of the wind power plant can be inhibited; wind power scheduling can be optimized; the control of reactive power, reactive voltage and power factors ofthe wind power plant can be better completed; the demand of power grid guidance on the grid connected voltage control precision can be met.

The invention relates to a method for digital control high frequency switching power supply technique in constant potential apparatus. It belongs to cathode protection technique field. The invention is made up of ac power supply rectification filter circuit, inverter circuit, high frequency rectification filter circuit, synthesis operation display control circuit, feedback signal isolation A / D conversion circuit, isolation predrive circuit, power semiconductor drive circuit, power semiconductor overflow protection circuit, and high speed digital control pulse modulation unit. The constant potential apparatus has the effects of large power, high efficiency, small volume, light weight, and so on. The invention can improve control accuracy and efficiency, reduce volume-weight and heating, improve complete machine reliability of the constant potential apparatus.

The invention provides a combined piezoelectric and pressurizing electromagnetic fuel gas injection device which comprises a pressurizing part, an electromagnetic-piezoelectric control part, a double-piston part, a double needle valve nozzle part and an injection device shell.Electromagnetic valves and a piezoelectric control valve are adopted to control the fuel gas injection process of two nozzles respectively; the nozzle controlled by the electromagnetic valves can be switched between a pressurizing mode and a non-pressurizing mode flexibly, adjustable gas injection pressure and gas injection quantity of the gas injection device can be achieved in a work cycle by adjusting the work state and work order of the pressurizing electromagnetic valve, the nozzle electromagnetic valve and the piezoelectric control valve, and the power requirements of an engine under different working conditions and series engine power requirements are met.A seal band is designed between each needle valve and a corresponding needle valve seat, part of control oil is introduced to the seal bands through an oil duct to seal fuel gas, leakage of fuel gas can be effectively prevented, meanwhile control oil in a control cavity and sealing oil at the needle valves are the same, and static leakage of the fuel oil in the control cavity and the sealing bands can be effectively prevented.

The invention discloses a fast frequency modulation response communication method for a photovoltaic power station with a group series inverter. After a frequency regulating system sends a power setting command to a secondary power control device, the secondary power control device calculates the active power target values of all the inverters and broadcasts instructions containing the active power target values of all the inverters. After the inverters receive the instructions, no reply confirmation is required and the active power setting values corresponding to their own communication addresses can be analyzed and executed. A transformer measurement and control device is connected to the secondary power control device through RS485. The secondary power control device directly collects the active power on the transformer side and uploads it to the frequency regulating system. The frequency regulating system performs closed-loop regulation again according to the feedback value. The fast frequency modulation response communication method saves the time for collecting inverter operation data and the time for sequentially issuing instructions.

The invention relates to a double-manipulator multi-freedom-degree mechanical arm and belongs to the technical field of the multi-freedom-degree mechanical arm. The double-manipulator multi-freedom-degree mechanical arm comprises two manipulators, a main arm, a main motor, a main motor bevel gear, a rotating shaft bevel gear and a rotating shaft, wherein the two manipulators are each connected with the main arm through a rotary frame; the main arm is matched with the rotating shaft bevel gear through the rotating shaft; the rotating shaft bevel gear is meshed with the main motor bevel gear, and the main motor bevel gear is installed on a main motor shaft. The overall mechanical arm utilizes each electromotor as a driving link and realizes actions such as pitching and rotation by virtue of a gear mechanism, a crank-link mechanism and the like; the manipulators realize the actions such as rotation, stretch and retraction by virtue of mechanisms such as a gear and a screw, and thus the work of grabbing an object can be effectively implemented.

The invention belongs to technologies for aviation support equipment, and relates to an improved pitching assembly of a radar scanner for detecting foreign matters on runways. The improved pitching assembly comprises a right backup plate (1), a backup plate cover (2), a servo module (3), a right angular contact ball bearing (4), a pitching frame end cover, a left arm, a left angular contact ball bearing (7), a left backup plate, a backup plate cover (9), a pitching frame and a right arm. A pitching motor is a permanent-magnet direct-current brushless torque motor (20) and is of a hollow shaft sleeve type, a stator of the pitching motor is mounted on a servo frame (18), a rotor of the pitching motor is mounted on the left backup plate (21), the servo module (3) is mounted inside the pitching frame (18), a pitching angle is fed via a rotary transformer (26) sleeved on a revolving shaft (23), a revolving stator is fixed into the pitching frame by the aid of a hoop, and axial clearance and pre-tightening force can be regulated by the aid of a sleeve (25) and a jackscrew (24). The improved pitching assembly has the advantages of high transmission and scanning precision, capability of meeting the requirement on low scanning speed, light weight, small size, high system rigidity, protection grade and reliability and long service life.

The invention provides a combined type dual-electromagnetic-valve gas injection device which comprises a dual-electromagnetic-valve part, a dual-control-piston part, a dual-needle-valve nozzle part, an injection device upper end cover and an injection device shell. A high-pressure control oil inlet, two low-pressure oil drainage openings and a gas inlet are formed in the injection device shell. The dual-electromagnetic-valve part is composed of two electromagnetic valves, an electromagnetic valve body, an electromagnetic valve spring seat and an electromagnetic valve sealing base. The dual-control-piston part comprises a piston sleeve, a first piston, a first piston control cavity, a first needle valve control cavity, a second needle valve control cavity, a second piston and a second piston control cavity. The dual-needle-valve nozzle part is composed of a first needle valve, a second needle valve, a needle valve base, a nozzle sleeve, a first nozzle sealing ring belt and a second nozzle sealing ring belt. According to the combined type dual-electromagnetic-valve gas injection device, gas leakage and static leakage of control oil are avoided, the two electromagnetic valves are adopted for separately controlling two nozzles for gas injection, and the requirements for the power of engines under different working conditions and the power of series engines are met.

The present invention pertains to the field of firefighting equipment, concretely relates to an automatic foam proportional mixing digital display controlling module and consists of microcomputer control unit, sensor unit and driver unit. The microcomputer control unit consists of circuit board component, electric signal connector, display and operating mechanism, and housing. They are overlapped in the housing. The circuit board component consists of microprocessor, electric signal input interface, electric signal output interface and digital communication interface. The electric signal connector and the display and operating mechanism are inside the housing; the sensor unit includes water flowmeter, foam flowmeter, and one or several types of level sensor or pressure sensor; the driver unit includes one or several types of DC brushless motor driver and electric valve driver; the electric signal input interface, electric signal output interface and digital communication interface of the electric circuit component are connected to the sensing component of the sensor unit and the driving component of the driver unit with electric signal connector. The present invention may greatly raise the automation degree of proportional foam mixing, and realize accurate control and adjustment of less than 1% mixing proportion.

The invention discloses a launching vehicle high-reliability aligning control method and belongs to the design field of launching vehicle control systems. In each aligning control period, a pitch angle [eta] of a launching frame under a ground coordinate system and a yaw angle [sigma] of a revolution platform under the ground coordinate system are measured and collected, and the state information of an existing vehicle body of the launching vehicle, such as the transverse levelness and the longitudinal levelness under the ground coordinate system and an erection angle and a revolution angle under a vehicle body coordinate system are utilized to calculate the data such as the pitch angle of an equivalent launching frame under the ground coordinate system and the yaw angle of the revolution platform under the ground coordinate system. When measuring devices in the system have faults, the pitch angle of the equivalent launching frame under the ground coordinate system and the yaw angle of the revolution platform under the ground coordinate system are used in the control operation of the launching frame and the revolution platform, the launching process is still successful, and the reliability of the launching vehicle in the aligning control process is substantially improved.

The invention discloses a valve device. The valve device comprises a drive component and a valve base component. The valve base component is provided with an inlet and an outlet. The inlet communicates with a valve cavity. A sliding block supported through the valve base component is further included. The bottom face of the sliding block is attached to the top face of the valve base component. Thesliding block is provided with a runner part and a blockage part which are arranged around the rotation center of the sliding block in the circumferential direction. In the circumferential direction,the circulation areas of the runner part are different. The runner part communicates with the valve cavity. The drive component can drive the sliding block to rotate relative to the valve base component, accordingly, the runner part communicates with the outlet, or the blockage part closes the outlet. According to the valve device, through the structure improvement on a flow adjusting part, the phenomenon of jamming in the total-closing state is avoided; and the flow deviation of the valve device can be controlled within the small range, and accordingly the flow precision control requirementfor refrigerators and similar small refrigeration systems can be met.

The present invention proposes a proportional valve, including a valve body and a valve core; inside the valve body there is an accommodating cavity, which is divided into several sections of single cavities from top to bottom; the upper part of each single cavity has an annular extension cavity; each The valve body on both sides of the middle part of the single chamber is symmetrically provided with an inlet and an outlet; the valve core includes a number of single cores stacked from top to bottom, and several single cores are fixed by string rods, and the top of the string rods is connected to The output shaft of the driving motor; the single core includes a working single core and a sealed single core; the single core has a cylindrical core, and the core is accommodated in a single cavity; the upper part of the core has an annular extension edge, which is accommodated In the extension cavity; the core body of the working single core is provided with a through flow channel, and when one end of the flow channel is aligned with the inlet, the other end of the flow channel is aligned with the outlet. The present invention can adjust the maximum flow rate of the proportional valve, can be applied to occasions requiring various flow rates, and can meet the requirements of flow control accuracy.

The invention discloses an optical transmission system automatically optimizing transmit end in optical communication field and its automatic optimizing method. It includes transmit end and receive end as well as transmission line and monitoring channel route; where the transmit end includes: continuous wave light source, forced modulator, phase modulator, strength modulation driving circuit, phase modulation driving circuit, sampling optical coupler, automatic power control circuit, CPU system, transmit-end route transmitter, and output optical interface; the receive end includes: input optical interface, input optical coupler, receiver, Q-value tester, control CPU, and receive-end route transmitter. It can automatically implement system performance optimization without a large quantity of manual debugging, meeting operating and maintenance requirements of on-line equipment. It is applied to a system with signal FEC coding and also without signal FEC coding.

The invention belongs to the field of vibration isolation of ships and particularly relates to an air bag control system for a ship. An altitude valve-based air bag control device for a ship comprises a vibration isolation air bag, an altitude valve, a high pressure gas cylinder and a supporting device; when the total weight of equipment is increased, the height of the vibration isolation air bag is decreased to drive the altitude valve to descend, the rotating angel of a main shaft is increased, the air inlet of the altitude valve is opened, and gas in the high pressure gas cylinder enters the vibration isolation air bag through the altitude valve, so that the vibration isolation air bag is raised; when the total weight of the equipment is decreased, the height of the vibration isolation air bag is increased to drive the altitude valve to ascend, the rotating angle of the main shaft is decreased, the exhaust port of the altitude valve is opened, and gas in the vibration isolation air bag enters the air from the exhaust port. The composition of the control system is simplified to satisfy different control precision requirements. The supporting device of the control system has a height adjusting function, is used for arranging the initial operational height of the altitude valve, and plays a protective role after the air bag works normally.

The invention discloses a photovoltaic active power distribution network scheduling control method based on f-dp / dv. The method comprises the following steps: (1) actively collecting actual active power Ppcc at a power distribution network port; (2) calculating the power difference delta P between the port reference active power and the actual active power Ppcc; (3) carrying out frequency recoverycontrol on each photovoltaic power supply, collecting the output port frequency f of each photovoltaic power supply, and calculating the corrected rated frequency; (4) carrying out proportional scheduling control on each photovoltaic power supply, collecting the voltage and current of photovoltaic output according to the power difference delta P from a dispatching center and a preset rated value,and calculating to obtain a corrected rated value, (5) carrying out droop control on each photovoltaic power supply, inputting obtained values, and calculating a reference value through a droop formula; and (6) allowing each photovoltaic power supply to control actual output according to the dp / dv reference value. According to the invention, the robustness of the AC microgrid system can be improved, and the reliable control of the grid-connected island operation and switching of the AC microgrid system is realized.

The invention belongs to the technical field of aircrafts, and discloses a helicopter flight driving robot system. The helicopter flight driving robot system comprises a fuselage hanging frame, a fuselage bottom plate, a servo mechanism, a robot control box and a visual perception module, and the servo mechanism comprises a six-degree-of-freedom manipulator, a steering engine mechanical arm and a steering engine mechanical leg; the fuselage hanging frame is installed on a cockpit seat, and a space for containing the robot control box is formed in the fuselage hanging frame; the fuselage bottom plate is horizontally placed on the helicopter cockpit seat; the six-degree-of-freedom manipulator is used for controlling a helicopter steering column; the steering engine mechanical arm is used for controlling a helicopter collective pitch rod; the steering engine mechanical leg is used for controlling a helicopter rudder; and the visual perception module is used for monitoring the environment of a cockpit and the scene outside the cockpit. The robot system can be installed in the helicopter cockpit, the helicopter is independently piloted by connecting a robot executing mechanism and a helicopter control mechanism, and rapid switching between a manned mode and an unmanned mode of the helicopter can be achieved under the condition that the helicopter is not modified.

The invention discloses a valve device which comprises a driving part and a valve seat part, and further comprises a sliding block and a filtering part, wherein the valve seat part is provided with aninlet and an outlet; the inlet communicates with the valve cavity; the sliding block is supported by the valve seat part; the bottom surface of the sliding block fits the top surface of the valve seat part; the sliding block comprises flow channel parts and a blockage part which are circumferentially arranged around the rotating center of the sliding block; along the circumferential direction, the circulation areas of the flow channel parts are different; the flow channel parts communicate with a valve cavity; the sliding block can be driven by a driving part to rotate relative to the valve seat part, so that the flow channel parts can communicate with the outlet, or the outlet can be closed by the blockage part; and the filtering part is used for filtering a refrigerant which flows intothe flow channel parts. According to the valve device, the all-closed stuck phenomenon can be avoided through the structural improvement of a flow regulating part; furthermore, the flow deviation of the valve device can be controlled to be within a relatively small range; and accordingly, the requirements for the flow accuracy control of refrigerators and similar small-sized refrigerating systemscan be met.

The invention provides a method for reconstructing a flywheel system under on-orbit biased-momentum control switching of a spacecraft. A flywheel group linear programming model under an inequality constraint condition is established according to a biased momentum control target of the spacecraft, a flywheel recombination strategy is made according to an optimization criterion, the output maximization of the biased momentum in a direction of a pitch axis is achieved, and a flywheel control system is reconstructed. According to the method, a flywheel recombination biased angular momentum outputmodel under the constraint condition can be quickly established, the iterative optimal solution is carried out by adopting a simplex method, and a gyroscope is replaced to ensure normal on-orbit operation of a satellite.

The invention provides a device for the monitoring motion gesture of a rotating disk of an omnibearing propeller of a submersible. Linear scales are respectively arranged on the three hydraulic cylinders of the omnibearing propeller; a microprocessor sends out a command signal to determine a linear scale signal data channel; a data conversion unit receives the output signals of the linear scales corresponding to the hydraulic cylinders in real time, wherein the determined data signals are switched to a signal processing unit after level switch; the data signals are identified and processed by the microprocessor of the signal processing unit and then transmitted to the signal processing unit, the signal processing unit converts the displacement and channel information of the linear scales into an RS232 signal and then is accessed to an upper computer through a communication interface unit; and the upper computer displays in real time and stores the data at the same time. The monitoring device has the characteristics of high acquisition precision, low work voltage and power consumption, high reliability, simple structure and the like.

The invention discloses a nonlinear adaptive PQ control method of an inverter in a grid-connected state, comprising the following steps: (1) collecting the three-phase output voltage vabc and the output current iabc of the LCL output port; (2) according to the output voltage and current obtained in the step (1) to calculate the active power P and reactive power Q output from the inverter; (3) calculating the d-axis component v<*>[d] of the modulation voltage; (4) calculating the q-axis component v<*>[q] of the modulation voltage; (5) adjusting the parameters in the step (3) and the step (4) through the adaptive control scale function; and (6) subjecting the v<*>[d] and v<*>[q] obtained in the step (3) to dq0 / abc transform to generate a PWM modulation wave, wherein the PWM modulation wave is input to the PWM wave generator to generate the PWM control signal for controlling the inverter. The method of the present invention not only does not require complex multi-parameter tuning, but also can set the control accuracy and is simple and efficient.

The invention discloses a high-precision micro-displacement actuator utilizing a threaded parallel structure, which comprises two sets of parallel threaded screw rod structures, namely a first threaded screw rod and a first screw rod nut matched with the outside, and a second threaded screw rod with a hollow structure and a second screw rod nut matched with the outside, the first threaded lead screw and the second threaded lead screw are the same in spiral direction and have different thread leads, displacement output is achieved through the relative lead difference between the first threaded lead screw and the second threaded lead screw, the first threaded lead screw is connected with the mirror face through the guide rod, the first lead screw nut and the second threaded lead screw are both connected with the motor, and the second lead screw nut is fixed to a telescope rack. The actuator is mainly used for accurately adjusting the position of the optical mirror surface in the field of astronomical telescopes, and the mirror surface is continuously displaced without a gap or backlash phenomenon when the position of the mirror surface is adjusted. The position adjustment precision of the mirror surface can reach a submicron level or even a nanometer level.

The invention discloses a pseudo-hierarchical control method for a direct current microgrid system under photovoltaic high permeability. A photovoltaic panel is connected to a direct current microgridthrough a Buck circuit. The method comprises the following steps: adding a proportional scheduling part, a voltage regulation part and a droop control part into the microgrid system; actively collecting the actual active power Ppcc at the port of the power distribution network; calculating a power difference delta P between the port reference active power and the actual active power Ppcc, and transmitting the power difference delta P to each photovoltaic power supply; carrying out proportional scheduling control, voltage regulation control and droop control on each photovoltaic power supply to obtain a photovoltaic power supply output dp / dv reference value; and enabling each photovoltaic power supply to control actual output according to the dp / dv reference value. By means of the method,the photovoltaic generator keeps certain hot standby power to participate in mitigation of power fluctuation, equal-proportion schedulable control over the photovoltaic generator in the microgrid system is achieved, the stability and robustness of the direct-current microgrid system are improved, and reliable control over grid connection-island operation and switching of the direct-current microgrid system is achieved.

The invention provides an electromagnetic and piezoelectric combined fuel gas injection device. Gas injection is carried out by double needle valve nozzles to meet gas injection requirements under different working conditions of an engine, fuel gas injection processes of the two nozzles are controlled by an electromagnetic valve and a piezoelectric control valve respectively, and when the electromagnetic valve or the piezoelectric control valve works independently, only one nozzle is used for gas injection, and the control accuracy requirement of a low load of the engine on small-flow gas injection is met; when the electromagnetic valve and the piezoelectric control valve work simultaneously, the two nozzles are used for gas injection simultaneously, and the requirements of a high load of the engine on a gas injection amount and gas injection stability are met; and a sealing ring belt is designed between each needle valve and a corresponding needle valve seat above two needle valve cavities, a part of control oil is introduced to each sealing ring belt to seal a fuel gas through an oil channel, leakage of the fuel gas can be effectively prevented, the same oil is adopted as control oil in control cavities and sealing oil at the needle valves, and static leakage of fuel oil in the control cavities and the sealing ring belts can be effectively prevented.

The invention discloses a valve device which comprises a driving part and a valve seat part, and further comprises a sliding block and a filtering part, wherein the valve seat part is provided with aninlet and an outlet; the inlet communicates with the valve cavity; the sliding block is supported by the valve seat part; the bottom surface of the sliding block fits the top surface of the valve seat part; the sliding block comprises flow channel parts and a blockage part which are circumferentially arranged around the rotating center of the sliding block; along the circumferential direction, the circulation areas of the flow channel parts are different; the flow channel parts communicate with a valve cavity; the sliding block can be driven by a driving part to rotate relative to the valve seat part, so that the flow channel parts can communicate with the outlet, or the outlet can be closed by the blockage part; and the filtering part is used for filtering a refrigerant which flows intothe flow channel parts. According to the valve device, the all-closed stuck phenomenon can be avoided through the structural improvement of a flow regulating part; furthermore, the flow deviation of the valve device can be controlled to be within a relatively small range; and accordingly, the requirements for the flow accuracy control of refrigerators and similar small-sized refrigerating systemscan be met.