55results about How to "Less design parameters" patented technology

The invention discloses a nonlinear self-adaption control method of near-space hypersonic vehicle (NHV), which belongs to a flight control method in the technical field of aerospace. The control method mainly comprises three control law parts: a nominal nonlinear generalized predictive control law (NGPC), a B-spline recursive functional linkage network (BRFLN) self-adaption control law, and a robust control law of gain self-adaption adjustment. The invention integrates the simplicity of the NGPC method and the effectiveness of dynamic uncertainty of the BRFLN learning, targets the immeasurable dynamic uncertainty and fast interference of an attitude system in the flight of the NHV, brings favorable learning effect, and realizes the nonlinear accurate control to the attitude angle.

The invention relates to a vertical takeoff and landing reusable launch vehicle attitude tracking control method based on a fixed time convergence observer, which belongs to the technical field of aircraft control. The method derives an attitude tracking error state equation based on a reentry coordinate system, all modeled and unmodeled dynamics of the system except a control moment are treated as system disturbances, converting to a second-order double-integral state equation is carried out, and the complexity of the system is further simplified.

The invention relates to a design method for row space between pressure relief boreholes. The method comprises the following three steps of: before the row space between the pressure relief boreholes is designed, firstly, requiring to evaluate the stress environment of a pressure relief site, and calculating a working face (roadway) surrounding rock supporting pressure peak value [Sigma]p and a peak value position Lp; selecting a surrounding rock on the Lp as an analysis object, adopting a corrected surrounding rock elastoplasticity analytical solution to calculate a borehole plastic zone radius rp, taking the rp as an index for evaluating the single-hole action range of the borehole, and determining the maximum row space between the boreholes as R which is less than or equal to 2rp; and meanwhile, adopting the elastoplasticity analytical solution to calculate the evolution curve of the circumferential stress [Sigma][Theta] of the borehole, taking the stress of a crosspoint of the circumferential stress curves of the adjacent boreholes as [Sigma]m, taking the stress [Sigma]0 of primary rock of an experiment site as an evaluation index, and determining the condition of the minimum row space R between the boreholes as [Sigma]m which is greater than or equal to [Sigma]0. The method is simple in operation and high in practicality and can be applied to fields including high-stress roadway pressure relief, rock burst prevention and treatment, high gassy seam permeability increasing and the like, the design accuracy of the row space between the boreholes can be effectively improved, and a borehole engineering quantity is lowered.

The invention provides an adaptive fault tolerance control method for a vertical take-off and landing reusable launch vehicle. The method comprises the steps of: Step 1: obtaining a guidance command;Step 2: establishing a landing section fault tolerance control model; Step 3: designing a fixed time convergence and expansion state observer; step 4: designing a non-singular fast terminal sliding mode surface; and Step 5: designing an adaptive fault tolerance controller. According to the adaptive fault tolerance control method, this design pattern not only effectively improves the rejection capability of the system to the complex external interference and the adaptive fault tolerance performance under various engine failure modes, but also guarantees the rapid and accurate tracking of the attitude guidance command.

The invention relates to a track dip angle inversion controlling method of an aircraft based on a control force limitation situation. The track dip angle inversion controlling method comprises the following four steps of: step 1, constructing a longitudinal model of an aircraft and converting a state of the aircraft; step 2, carrying out an inversion control design based on saturated control input; step 3, verifying tracking performance and regulating parameters; and step 4, finishing the design. The invention aims at a longitudinal plane dynamic model of the aircraft, utilizes an input saturation error dynamic amplification method by defining an auxiliary analysis system to realize an inversion control method based on the saturated control input, and is applied to the control of a track dip angle of the aircraft. The invention has better practical value and a wide application prospect in an aerospace automatic control technical field.

The invention discloses a multilayer segmented built-in permanent magnet synchronous motor used for electric automobile driving. A built-in rotor part comprises a rotor iron core, a three-layer segmented neodymium-iron-boron magnetic steel and a magnetic barrier. By optimizing a pole-arc coefficient of every layer of a permanent magnet, the harmonic content of the gap flux density of the built-in permanent magnet synchronous motor is minimized, and therefore the torque ripple and the iron core loss of the built-in permanent magnet synchronous motor are reduced. By adopting the multi-layer mechanism, the salient pole rate of the motor reaches more than three, and the flux weakening capability of the motor is improved. Each permanent magnet is divided into four segments, and therefore the eddy current loss of the permanent magnet is reduced, the heating of the permanent magnet is reduced, and an anti-irreversible demagnetization capability is improved, and the reliability of the motor is improved. Compared with the prior art, the torque ripple and the iron core loss of the permanent magnet synchronous motor, and the permanent magnet eddy current loss are reduced, and the noises of the operation of the motor are reduced, and the operation efficiency and the reliability of the electric automobile driving motor are improved.

The double spherical shock absorbing and insulating bearer for railroad bridge includes an upper bearing plate, a middle bearing plate and a lower bearing plate superposed successively and sliding teflon plates set between bearing plates. The lower bearing plate has fixed shearing force member. The middle bearing plate has an upper spherical surface in small curvature radium for connection to the upper bearing plate through spherical spin friction, and a lower spherical surface in great curvature radium for connection to the lower bearing plate through spherical sliding friction. In addition, there are also a top basin on the upper bearing plate and a sliding teflon plate in between. the present invention has obvious shock absorbing and insulating effect, easy control and regulation, capacity of ensuring structural safety and lowering engineering cost, and other features.

The invention discloses a hypersonic speed maneuvering flight anti-rudder surface saturation resistance robust control method, belongs to flight control methods in the technical field of aviation and aerospace, and aims to solve the problem of poor control system performance of a HSV (hypersonic vehicle) caused by operating control surface amplitude saturation and composite disturbance in the hypersonic speed maneuvering flight process. The method provides a novel saturation resistance auxiliary design system, the order of the system is as same as that of an attitude control system, and the system is applicable to an SISO (single input single output) system and an MIMO (multiple input multiple output) system. Variables of the auxiliary system is led into a back-stepping method error variables, HSV maneuvering flight control laws are designed by the aid of the back-stepping method ideologies, and the closed loop stability of a system is ensured. The invention provides a disturbance observer based on a mixed tracking differentiator, tracking and approach for composite disturbance are performed by the disturbance observer, and compensation control laws are designed.

The present invention is parallel triaxial spindle head structure and belongs to the field of machine building technology. The parallel triaxial spindle head structure includes one spindle, one movable platform, one fixed platform, and three identical branches to connect the movable platform and the fixed platform, with the spindle being fixed onto the movable platform. Each of the three branches includes one input rod member, one multivariant hinge connected to the movable platform, and two kinematic pairs, including one driving one connected between the input rod member and the fixed platform and one driven one connected between the input rod member and the multivariant hinge. The present invention may operate alone or through coordination with other device, and has high rigidity, low moving mass, high dynamic performance, simple structure, low cost and other advantages.

The invention discloses an automatic gain control circuit for closed-loop drive of an MEMS gyroscope. The automatic gain control circuit comprises an amplitude comparator, a residual selector and a loop filter. The amplitude comparator automatically determines whether a gyroscope is in an oscillation starting phase or a stabilizing phase based on the magnitude of an output signal of the amplitude detector, and outputs a control signal for controlling an operation mode of the loop filter and the residual selector according to the determination result. The residual selector outputs an input signal required for the loop filter according to the control signal output from the amplitude comparator and a preset digital reference value. The loop filter generates a drive amplitude signal based on the input signal and the control signal output from the amplitude comparator. The invention designs the amplitude comparator in the automatic gain control circuit to realize the self-detection of a drive system and to adaptively adjust the operation mode of an automatic gain controller; and the oscillation starting time can be less at very small loop bandwidth, the stabilizing time is shorter, meanwhile, fewer design parameters are needed, and the system is more concise.

The invention relates to a real-time estimation method of a road adhesion coefficient under a braking working condition. According to the real-time estimation method disclosed by the invention, a two-wheeled vehicle braking dynamics model, an ideal braking torque controller and a road adhesion coefficient observer are adopted, wherein the two-wheeled vehicle braking dynamics model consists of a full vehicle model and a tire model; based on the two-wheeled vehicle braking dynamics model, a saturation function and an integral switching surface are adopted to redesign a sliding mode controller, so that a shake problem is solved, and the ideal braking torque controller is set up. Based on the two-wheeled vehicle braking dynamics model and the ideal braking torque controller, a second order linear extended state observer is adopted to design the road adhesion coefficient observer and to observe an extended state quantity which is relevant with an adhesion coefficient, and then the real-time estimation of the road adhesion coefficient is completed. According to the real-time estimation method disclosed by the invention, the quantity of design parameters is small, the calculating efficiency is high, and the modes of the saturation function and the integral switching surface are adopted to solve the shake problem which is controlled by a sliding mode variable structure; the road adhesion coefficient observer adopts the second order linear extended state observer, so that the robustness is strong.

The invention belongs to the technical field of the environmental protection, and in particular relates to an optimization design method of sewage treatment plant A2 / O process. According to the weaknesses of the prior sewage treatment plant A2 / O process that the traditional design method has high basic construction expense, high running expense and the like, the optimization design method adopts an active mud 2D model as a mechanism to respectively carry out the model construction of three biological reaction tanks (anaerobic tank, anoxic tank and an aerobic tank) and a sedimentation tank so as to establish an optimization design model of the sewage treatment plant and to optimize the design parameters in the A2 / O process, a mantlab language is used for programming a program main body, and 1stOpt software is adopted to carry out the final solving so as to obtain the design results of different parameters. Compared with the traditional design method, the optimized design method facilitates the appropriate dereferencing of each design parameter of the sewage treatment plant; therefore, on the premise that the outlet water quality is satisfied, the construction and running cost of the sewage treatment plant is reduced. The optimization design method is applicable to the design of a new sewage treatment plant and to the running management of a built sewage treatment plant.

The invention discloses a ship motion control simulation platform which comprises a control module, a driving module, an attitude measurement module, a position determination module and a power module. The driving module is used for controlling the forward movement and turn of a motion platform. The attitude measurement module and the position determination module are used for measuring the attitude and position data of the motion platform. The control module is provided with a track tracking algorithm and a deck motion model. The control module obtains the attitude and position information of the motion platform from the attitude measurement module and the position determination module and then carries out track tracking calculation, then a ship moves according to an expected path through the driving module according to a calculation result, and the deck movement of the ship in waves can be simulated at the same time. Further, the invention also discloses a ship motion control method. Through the platform or the method and an indirect control method of separating heading control and track control, the control parameter adjustment is simple, and a heading control and a track control algorithm can be modified separately.

The invention relates to an alternating current side wiring structure of a direct current transmission system of a power supply converter and a control method of the alternating current side wiring structure. The wiring structure comprises an upper stage circuit breaker CB1, an access circuit breaker CB2, a transformer T, a start resistor R and an alternating current circuit breaker CB3, wherein an alternating current incoming line of a converter station is led to a power supply from the upper stage circuit breaker CB1, the upper stage circuit breaker CB1 is connected with the transformer T through the access circuit breaker CB2, the start resistor R and the alternating current circuit breaker CB3 constitute a parallel circuit, and the transformer T is connected with the converter C through the parallel circuit constituted by the start resistor R and the alternating current circuit breaker CB3. When the direct current side of the converter breaks down, control protection is performed to simultaneously send commands for skipping the alternating current incoming line circuit breaker and the circuit breaker connected with the start resistor in parallel. Under the condition that the alternating current incoming line circuit breaker fails, the start resistor is connected into the fault circuit, and thus a fault current flowing through the converter before the skipping of the upper stage circuit breaker is effectively reduced, safety of a converter valve is protected and design parameters of original components of equipment are reduced.

The invention discloses a satellite channel complex-valued neural polynomial network blind equalization system and a method. According to the invention, a complex-valued neural polynomial network is adopted as a blind equalization module, wherein a single-layer neural network is used to compensate the linear characteristic of a satellite channel, and a nonlinear memoryless processor is used to compensate the nonlinear characteristic of the satellite channel. A six-layer fuzzy neural network controller is designed by building fuzzy control rules, and a sixth-layer weight vector is adjusted by a fixed-step constant modulus approach. The six-layer fuzzy neural network controller controls the iteration step length of the weight vectors of the single-layer neural network and the nonlinear memoryless processor at high precision. The satellite channel complex-valued neural polynomial network blind equalization system has the advantages of simple structure, high convergence rate and small steady-state error. The problem of high complex-valuedity is well solved. The contradiction between convergence rate and mean square error is overcome effectively.

The invention provides a wind turbine pitch variation execution mechanism robust control method based on H-infinity mixed sensitivity. The method comprises the following steps: establishing an open-loop transfer function GP (s) of a pitch variation execution mechanism; establishing a sensitivity function S and a complementary sensitivity function T; establishing weighting functions W1, W2, and W3 meeting constraint conditions; and establishing a closed-loop system transfer function Tzw (s) of a generalized controlled object of the pitch variation execution mechanism, and further obtaining a transfer function K(s) of an H-infinity controller Chinf. According to the method, the H-infinity mixed sensitivity robust control is applied to the wind power generation pitch variation execution mechanism, and an advanced control plan is provided for the pitch variation execution mechanism to carry out rapid and accurate pitch variation command tracking, thereby reducing tracking error, and improving tracking performance, dynamic performance, robust performance and anti-interference capability of the pitch variation execution mechanism.

The invention provides an automatic optimization method for a turbomachinery blade, and the method comprises the following steps: performing parametric modeling on an initial blade profile by adopting an improved category shape transformation method, and flexibly constructing a suction surface molded line and a pressure surface molded line of the blade profile on the basis of applying fewer variables, so the method has the advantages of good robustness, few design parameters, high modeling precision and the like; employing a sample sampling method, an agent model and a cubic chaotic mapping whale optimization algorithm for automatically optimizing the blades, so the method has the advantages of high sampling efficiency, high agent precision, high optimization capacity and the like. By applying the automatic optimization method, the comprehensive performance of the impeller mechanical blade is improved.

The invention discloses a composite material X-shaped support structure optimization design method and system for connecting a fuel storage tank, and the method comprises the steps: firstly determining design parameters according to the structural features of a composite material X-shaped support, and building a parameterized geometric model; carrying out finite element analysis on the integral model containing the fuel storage tank and the composite material X-shaped support, and determining a displacement boundary condition; based on the parameterized geometric model, establishing a finite element model of the composite material X-shaped support, and utilizing an experiment design method to obtain an optimization design variable; establishing an optimization design model based on the parameterized geometric model, the displacement boundary conditions and the optimization design variables, and obtaining optimization design parameters meeting constraint conditions; and finally, based on optimization design parameters and selection of a layering mode, establishing a finite element model based on layering for strength check analysis, and obtaining the composite material X-shaped support structure meeting the strength design requirement. The composite material X-shaped support structure designed by the design method has the advantages of light weight and high strength.

The invention discloses an anti-saturation model-free preset performance trajectory tracking control method for an autonomous surface vehicle, and belongs to the technical field of unmanned surface vehicle anti-interference control. The anti-saturation model-free preset performance trajectory tracking control method for the autonomous surface vehicle comprises the following steps: step 1, establishing an unmanned surface vehicle kinetic model considering external interference; 2, establishing a saturation function model; 3, designing an anti-saturation controller independent of the model information; and 4, verifying the stability and robustness of the unmanned ship control system. By designing the error conversion equation and the saturation function model, saturation tracking control can be achieved only by adjusting the preset performance parameters, the structure is simple, the number of design parameters is small, and good applicability is achieved in the engineering aspect.

The invention discloses an integral low-temperature nuclear heat reactor with the circuit equipment adopting integral arrangement and belonging to the low- and medium-parameter pressurized-water reactor, wherein, a reactor core adopts the mature nuclear power plant fuel component and control rod component; a main heat exchanger is of integral coil type; a voltage stabilizer is a built-in nitrogenpartial pressure control voltage stabilizer; coolant circulation is completed by a built-in jet apparatus and the equipment of an external drive circuit; the drive circuit and the equipment and a main circuit auxiliary system are arranged at the circumference of a reactor pressure vessel; a containment vessel consists of a reactor body containment vessel and a reactor top containment vessel; the reactor body containment vessel which is a structure combined by a reactor vault of reinforced concrete structure and a casing of steel structure is connected with a sealed refueling water storage pool through a pipe and a valve. The thermal power of the reactor can be selected between 50MW and 500MW at will and the outlet temperature of the reactor can be selected between 100 DEG C to 200 DEG C according to application, requirement and power.

The invention belongs to the technical field of multi-agent cluster control, and particularly discloses a multi-agent cluster control method inspired by physicochemistry, which comprises the steps offirstly, carrying out model abstraction; secondly, introducing a probability density distribution function of virtual electrons to construct a potential energy functional; then obtaining a cluster control law by solving a Lagrange equation of a non-isolated mass point system; and finally, introducing a dissipative structure theory to evaluate whether the cluster control law has the potential of controlling the initially disordered agent group to a stable ordered structure, if the control law meets three necessary conditions of the dissipative structure theory, performing stability and convergence analysis on the designed control law by adopting a similar Lyapunov method, and judging whether the intelligent agent group can form a stable time-progressive cluster or not. According to the method, the problem that a complex experience potential field needs to be constructed in the cluster control law design process of a traditional social force model is solved, and a complete theoretical basis is provided for cluster control stability and accessibility.

The invention discloses an electromagnetic docking control method and a device, which adopt an anomalous magnetic moment control plus one-time magnetic moment switching mode, wherein the electromagnetic docking control method includes the following steps: according to the magnetic induction intensity of a target electromagnetic device, the initial speed and initial magnetic moment of a tracking electromagnetic device and the initial distance between the barycenters of the target electromagnetic device and the tracking electromagnetic device, the initial mechanical energy of a docking system is calculated; according to the set switching speed and initial magnetic moment of the tracking electromagnetic device and the initial mechanical energy of the docking system, the switching distance, which corresponds to the switching speed, between the barycenters of the target electromagnetic device and the tracking electromagnetic device is calculated; according to the switching speed, the switching distance and the expected docking speed and expected docking distance of the tracking electromagnetic device, the switching magnetic moment of the tracking electromagnetic device is calculated; when the speed of the tracking electromagnetic device is changed into the switching speed, the electromagnetic moment of the tracking electromagnetic device is transformed into the switching magnetic moment. The invention solves the technical problem that the design of the conventional method is complex and the requirement for control design robustness is high.

The invention discloses a nonlinear self-adaption control method of near-space hypersonic vehicle (NHV), which belongs to a flight control method in the technical field of aerospace. The control method mainly comprises three control law parts: a nominal nonlinear generalized predictive control law (NGPC), a B-spline recursive functional linkage network (BRFLN) self-adaption control law, and a robust control law of gain self-adaption adjustment. The invention integrates the simplicity of the NGPC method and the effectiveness of dynamic uncertainty of the BRFLN learning, targets the immeasurable dynamic uncertainty and fast interference of an attitude system in the flight of the NHV, brings favorable learning effect, and realizes the nonlinear accurate control to the attitude angle.

The invention provides a wind turbine pitch variation execution mechanism robust control method based on H-infinity mixed sensitivity. The method comprises the following steps: establishing an open-loop transfer function GP (s) of a pitch variation execution mechanism; establishing a sensitivity function S and a complementary sensitivity function T; establishing weighting functions W1, W2, and W3 meeting constraint conditions; and establishing a closed-loop system transfer function Tzw (s) of a generalized controlled object of the pitch variation execution mechanism, and further obtaining a transfer function K(s) of an H-infinity controller Chinf. According to the method, the H-infinity mixed sensitivity robust control is applied to the wind power generation pitch variation execution mechanism, and an advanced control plan is provided for the pitch variation execution mechanism to carry out rapid and accurate pitch variation command tracking, thereby reducing tracking error, and improving tracking performance, dynamic performance, robust performance and anti-interference capability of the pitch variation execution mechanism.

The invention relates to an air inflation free tire structure comprising an inner ring connected to a hub, an outer ring connected to tread rubber and an N-type elastomer connected to the inner and outer rings to form an annular air inflation free tire. The N-type elastomer comprises a plurality of elastomeric spokes in the radial direction of the tire, and the widths of the two spokes between theradial spokes respectively occupy half of the width of the radial spokes. The elastomeric spokes are staggered on both sides to be connected to the inner and outer rings. The air inflation free tirecan reduce tire weight and rolling resistance and prevent the occurrence of puncture.

The invention discloses a heat recovery system with a plurality of stages of hybrid heaters. Specifically, the heat recovery system comprises a BEST machine, five high-pressure heaters, five low-pressure heaters, the two to five hybrid heaters, boosting pumps and a condensate pump; each hybrid heater is configured with the corresponding boosting pump; the condensate pump is positioned between thelow-pressure heaters and a steam condenser; extraction steam of the first high-pressure heater is from a main steam turbine; the extraction steam of the second high-pressure heater to the fifth high-pressure heater is from the BEST machine; steam sources of the hybrid heaters are all from the BEST machine, wherein the steam source of the last stage hybrid heater is from the exhaust steam of the BEST machine; the extraction steam of the five low-pressure heaters is from the main steam turbine; and the last stage hybrid heater is connected with one of the low-pressure heaters, and the water supply of the last stage hybrid heater is from the low-pressure heater. According to the heat recovery system with the plurality of stages of deaerators, the circulating efficiency of the system is improved; the superheat degree of the steam is fully utilized; the project cost is reduced; the cold end loss of the steam is reduced; and the heat recovery system with the multiple stages of deaerators isparticularly suitable for the situation that the steam extracting steam of a plurality of heaters are close to the saturation pressure of the steam, and the feed water flow is large.

The invention relates to a design method for row space between pressure relief boreholes. The method comprises the following three steps of: before the row space between the pressure relief boreholes is designed, firstly, requiring to evaluate the stress environment of a pressure relief site, and calculating a working face (roadway) surrounding rock supporting pressure peak value [Sigma]p and a peak value position Lp; selecting a surrounding rock on the Lp as an analysis object, adopting a corrected surrounding rock elastoplasticity analytical solution to calculate a borehole plastic zone radius rp, taking the rp as an index for evaluating the single-hole action range of the borehole, and determining the maximum row space between the boreholes as R which is less than or equal to 2rp; and meanwhile, adopting the elastoplasticity analytical solution to calculate the evolution curve of the circumferential stress [Sigma][Theta] of the borehole, taking the stress of a crosspoint of the circumferential stress curves of the adjacent boreholes as [Sigma]m, taking the stress [Sigma]0 of primary rock of an experiment site as an evaluation index, and determining the condition of the minimum row space R between the boreholes as [Sigma]m which is greater than or equal to [Sigma]0. The method is simple in operation and high in practicality and can be applied to fields including high-stress roadway pressure relief, rock burst prevention and treatment, high gassy seam permeability increasing and the like, the design accuracy of the row space between the boreholes can be effectively improved, and a borehole engineering quantity is lowered.

The invention relates to a vertical takeoff and landing reusable launch vehicle attitude tracking control method based on a fixed time convergence observer, which belongs to the technical field of aircraft control. The method derives an attitude tracking error state equation based on a reentry coordinate system, all modeled and unmodeled dynamics of the system except a control moment are treated as system disturbances, converting to a second-order double-integral state equation is carried out, and the complexity of the system is further simplified.

The invention relates to a track dip angle inversion controlling method of an aircraft based on a control force limitation situation. The track dip angle inversion controlling method comprises the following four steps of: step 1, constructing a longitudinal model of an aircraft and converting a state of the aircraft; step 2, carrying out an inversion control design based on saturated control input; step 3, verifying tracking performance and regulating parameters; and step 4, finishing the design. The invention aims at a longitudinal plane dynamic model of the aircraft, utilizes an input saturation error dynamic amplification method by defining an auxiliary analysis system to realize an inversion control method based on the saturated control input, and is applied to the control of a track dip angle of the aircraft. The invention has better practical value and a wide application prospect in an aerospace automatic control technical field.

The invention discloses a heat recovery system with a plurality of stages of hybrid heaters. Specifically, the heat recovery system comprises a BEST machine, five high-pressure heaters, five low-pressure heaters, the two to five hybrid heaters, boosting pumps and a condensate pump; each hybrid heater is configured with the corresponding boosting pump; the condensate pump is positioned between thelow-pressure heaters and a steam condenser; extraction steam of the first high-pressure heater is from a main steam turbine; the extraction steam of the second high-pressure heater to the fifth high-pressure heater is from the BEST machine; steam sources of the hybrid heaters are all from the BEST machine, wherein the steam source of the last stage hybrid heater is from the exhaust steam of the BEST machine; the extraction steam of the five low-pressure heaters is from the main steam turbine; and the last stage hybrid heater is connected with one of the low-pressure heaters, and the water supply of the last stage hybrid heater is from the low-pressure heater. According to the heat recovery system with the plurality of stages of deaerators, the circulating efficiency of the system is improved; the superheat degree of the steam is fully utilized; the project cost is reduced; the cold end loss of the steam is reduced; and the heat recovery system with the multiple stages of deaerators isparticularly suitable for the situation that the steam extracting steam of a plurality of heaters are close to the saturation pressure of the steam, and the feed water flow is large.