819 results about "Constant power" patented technology

The invention belongs to the technical field of plasma sources, and provides a high-power high-stability remote plasma source fuzzy hysteresis control method and a circuit, when a reaction cavity is successfully ignited, a plasma source system is controlled to work at constant-frequency variable-duty-ratio constant-power output, and the method comprises the following steps: according to a sampled current value, a duty ratio, a predicted current value and a predicted duty ratio, calculating a constant-frequency variable-duty-ratio constant-power output value; respectively obtaining error control variables e and ec; the error control variables e and ec serve as input values of a fuzzy controller, and the actual control quantity hr output by the fuzzy controller is obtained; obtaining compensation variables # imgabs0 # and # imgabs1 # of the current and the duty ratio based on the error control variables e and ec; and taking the actual control quantity hr as the ring width value of a hysteresis comparator, and respectively compensating the current # imgabs4 # and the duty ratio # imgabs5 # at the moment k by outputting compensation variables # imgabs2 # and # imgabs3 # according to a preset rule. According to the method provided by the invention, a power window in a relatively wide range can be ensured, so that the working stability of the remote plasma source is improved, and the uniformity of a semiconductor manufacturing process is improved.

The invention discloses a coordination control method for energy storage and a flexible multi-state switch in a power distribution network system, and relates to the field of power supply and distribution. The hierarchical control mode is adopted to coordinate the energy storage system and the flexible multi-state switch; the coordination control layer performs working mode selection and switching in a networking operation mode by a centralized controller according to the feeder load power, the charge state of a storage battery, the operation state of each transformer and the position and the number of feeder faults; the control strategy of the flexible multi-state switch can be changed among a constant DC voltage control strategy, a constant power control strategy and a droop control strategy; the control strategy of the storage battery can be switched among constant-current charging control, floating charging control and constant-voltage control; and the feeder load in the equipment control layer can also realize a load switching control strategy. By adopting the coordination control method, the power supply reliability and the power quality of the system can be improved.

The invention relates to the technical field of ship propulsion power generation system control, in particular to a constant-power rotating speed control method and system for a ship shaft generator, and the method comprises the following steps: obtaining operation state parameters and ship environment parameters of a ship propulsion power generation system; based on the operation state parameters and the ship environment parameters, the influence of the adjusting action of the shaft generator on the rotating speed of a main propulsion diesel engine and the influence of the adjusting action of a main propulsion diesel engine speed adjusting device on the output power of the shaft generator are pre-judged, and an interactive pre-judgment result is obtained; according to the interactive pre-judgment result, jointly deciding and generating a first adjusting instruction for adjusting an axle generator and a second adjusting instruction for adjusting a main propulsion diesel engine speed adjusting device; by introducing an interactive pre-judgment and joint decision-making mechanism, the negative interaction between the shaft generator and the main propulsion diesel engine speed regulation device can be effectively identified and eliminated, and the operation stability and safety of the ship under the severe sea condition are improved.

The invention discloses an ignition control method of a remote plasma source in the technical field of remote plasma sources, which comprises the following steps: S1, setting a gas current excitation threshold value, and introducing excitation gas; s2, judging whether an ignition signal is received or not, and if yes, closing a relay and entering a constant current stage; s3, whether system ignition is normal or not is judged, and if not, the ignition voltage is adjusted through a self-learning type ignition threshold value calibration method; s4, the output power is improved, and the ignition voltage is adjusted through an ignition threshold calibration method during the period; s5, entering a constant power stage when the output power reaches the full-load power; according to the self-learning type ignition threshold value calibration method, gas flow, gas pressure and cavity temperature are collected in real time, a current load impedance value is predicted through an LSF-BP model, and an ignition voltage threshold value is updated according to the current load impedance value. According to the method, the ignition threshold is dynamically adjusted according to the operation condition, the ignition stability can be effectively improved, and equipment damage and maintenance cost are reduced.

The invention discloses a short-circuit current limiting and short-circuit recovery transient voltage control device and method for an aviation three-stage power generation system, and the device comprises a three-stage power generator, a power generator controller, a current sensor, a voltage and current collection module, and an asymmetric half-bridge excitation control circuit. Collecting the output current iL and voltage UL of the generator through a digital processor of the generator controller; when short circuit occurs, the given voltage USet of the voltage regulating loop is linearly reduced in a piecewise mode according to the relation between the iL and a preset threshold value, so that the generator works in a constant power interval; and when the short circuit is recovered, closing the upper / lower power tubes of the asymmetric half-bridge excitation control circuit according to the relationship between UL and a preset threshold value in a grading manner, and triggering a negative-pressure follow-current mode of a main excitation winding of the generator controller to quickly extinguish the field. The method can adapt to different generators without adjusting hardware circuit parameters, has no motor ablation risk during short circuit, has transient voltage less than 350V after short circuit recovery, has no power supply interruption in the whole process, has response delay less than 1ms, and greatly improves the safety and robustness of an aviation power supply and distribution system.

The invention discloses a power supply method, a power supply system and a cabinet, the method is applied to the power supply system, the power supply system comprises a PSU and an explosion power supply module, both the PSU and the explosion power supply module are connected with a bus of the cabinet, and the method comprises the following steps: detecting the state of the cabinet where the power supply system is located; and when the state shows that the cabinet has a transient power supply event, triggering the PSU and the explosion power supply module to supply power to the cabinet in a coordinated manner according to a transient power supply demand. The explosion power supply module is additionally arranged in the power supply system in the cabinet, and when the PSU supplies power to the cabinet at constant power, the explosion power supply module connected with the bus can obtain electric energy and store the electric energy. When a transient power supply event occurs in the cabinet, the explosion power supply module quickly supplements the electric energy required by the cabinet to supply power to the cabinet, so that the transient power supply requirement of the cabinet is met. Therefore, the power supply reliability of the cabinet when the transient power supply event occurs in the cabinet is improved.

The invention discloses a magnetic adjusting assembly, a motor, an electric drive system and a vehicle, and the magnetic adjusting assembly comprises a magnetic conductive part which is suitable for being movably disposed on one side of a rotor in the radial direction, so as to adjust the magnetic flux passing through the rotor. According to the magnetic adjusting assembly, the magnetic flux passing through the rotor is adjusted to change the magnetic flux of the magnetic flux short-circuit loop formed by the magnetic conductive piece and the rotor, so that the adjustment of the magnetic flux of the main magnetic field is realized, the adjustment is convenient, and the motor applying the magnetic adjusting assembly has the advantages of a constant torque area and a constant power area; and a constant-power operation region and a high-efficiency region are effectively widened while high torque density and power density are ensured.

The invention discloses a converter grid following-grid construction control mode smooth switching method suitable for wide-range source-grid state change. The method comprises the following steps: constructing a phase-locked loop control loop, a power outer loop control loop and a current inner loop control loop of a grid following type converter based on constant power control; constructing a voltage control loop, a phase control loop and a voltage and current double-closed-loop control loop of the network construction type converter based on the virtual synchronous generator VSG; calculating real-time output active power P and reactive power Q of the converter; constructing a voltage phase synchronization loop switching control loop and a current instruction tracking loop, and realizing smooth switching of dq-axis current instruction values output by a power outer loop of a following network type and a voltage outer loop of a construction network type; and the output dq-axis current instruction value is transmitted to a current inner loop to generate a final voltage signal, and a PWM wave is output to the converter through a modulation link. According to the method, a voltage phase synchronous switching compensation mechanism is adopted, a voltage amplitude and a phase signal are synchronously corrected in the mode switching process, and smooth change of an inner ring current reference signal is achieved.

The invention provides a constant-power load analog circuit, a constant-power adjusting method and a rack-mounted load box, and belongs to the field of rack-mounted load boxs.The analog circuit comprises a rectifying circuit, a diverter, a power module, a fan module and a control and drive circuit, and the power module comprises at least one heating tube and at least one transistor. The control and drive circuit comprises a main control circuit, a voltage signal processing circuit, a current signal processing circuit, a power setting and display module and at least one IGBT drive circuit, the base electrode of the transistor is connected to the main control circuit through the IGBT drive circuit, and the power setting and display module is connected to the main control circuit and used for inputting a set power value. The main control circuit collects voltage and current of an external power supply, calculates a rated power value, calculates a signal duty ratio according to a set power value and the rated power value, outputs a PWM wave, controls on or off of a transistor through the IGBT driving circuit, dynamically adjusts actual output power of the load simulation circuit to be consistent with the set power value, and controls the load simulation circuit to work. And the power regulation precision of the load box is improved.

The invention provides a constant-power driving method of a light source, a light source driver and an air conditioning system, and the constant-power driving method comprises the steps: determining an equivalent voltage corresponding to the power of the current light source based on the working current and working voltage of the current light source obtained in real time; performing differential amplification processing on the equivalent voltage and the expected voltage to generate a constant power modulation instruction of the light source; the expected voltage is a constant voltage simulated according to the rated power of the light source; driving power of the light source is generated based on a constant power modulation instruction of the light source and a feedback adjustment instruction, the driving power is amplified by using a preset power amplification coefficient, the amplified driving power is used for driving the light source to emit light, and the feedback adjustment instruction is generated based on sampling feedback of the driving power of the amplified light source. The constant-power driving of the light source is adopted, so that the service life, the precision and the response speed of the light source are ensured.

The utility model discloses a constant power controller with pressure control for a high-pressure plunger pump, which comprises a shell, a variable piston is arranged in the shell, a return spring connected with the shell is arranged at the small end of the variable piston, a shifting block rotationally connected with the shell is arranged on the radial side of the variable piston, and a power control valve is arranged on one side of the shifting block. A variable supporting column extending towards the shifting block is arranged on the variable piston in the radial direction, a guide hole is formed in the end face of the variable supporting column, the bottom face of the guide hole is communicated with the small end of the variable piston, a variable plunger is arranged in the guide hole and comprises a plunger body and a sliding shoe, the plunger body is in sliding connection with the variable supporting column, and one side of the sliding shoe is in spherical hinge joint with the plunger body. And the other side of the sliding shoe is in surface contact with the shifting block. The utility model has the advantages of longer service life and higher constant power control precision.

An automatic lock is disclosed. The lock can use a constant power spring to automatically lock itself when unlocked. The door lock can comprise a motor configured to charge a capacitor when a battery is depleted. The door lock can comprise a spindle extending from an exterior portion of the door lock to an interior portion of the door lock, mechanically linked to a key arm and a latch. When engaged, the key arm can allow the spindle to be turned by the exterior knob without actuating the latch, when disengaged, the key arm can allow the spindle to be turned by the exterior knob and actuate the latch.

The invention discloses a shutdown discharge method for an all-vanadium redox flow battery system. The all-vanadium redox flow battery system comprises an all-vanadium redox flow battery, a battery management system and an energy storage converter, the all-vanadium redox flow battery comprises a galvanic pile, an electrolyte, an electrolyte circulating pump and positive and negative storage tanks, the battery management system and the energy storage converter are independently and electrically connected with the all-vanadium redox flow battery; the battery management system is in communication connection with the energy storage converter through a communication protocol; after the all-vanadium redox flow battery system is shut down, when the SOC value of the all-vanadium redox flow battery is smaller than SOC3, shutdown discharging is not needed; and when the SOC value of the all-vanadium redox flow battery is greater than or equal to SOC3, the battery management system issues a discharging instruction to control the energy storage converter to discharge at constant power until the voltage of the all-vanadium redox flow battery is reduced to cut-off voltage V, and the battery management system issues a discharging stopping instruction to control the energy storage converter to stop discharging.

A DC electronic load circuit relates to the technical field of electronic load control. The utility model provides a direct current electronic load circuit which integrates a dissipation MOS tube array, an analog PID loop, a digital integrated control module, a bus electrical parameter sampling and processing module and a WiFi communication module, and realizes a plurality of working modes such as constant current, constant voltage, constant resistance and constant power by accurately controlling the conduction degree of the MOS tube array. The system has the advantages of real-time monitoring, remote control, overvoltage and overcurrent protection, low power consumption design and the like, and an electronic load solution which is high in precision, high in stability and flexible to operate is provided, so that diversified test requirements are met, and the power supply test efficiency and safety are improved.

The invention relates to the technical field of grinding control, in particular to a constant-power grinding control method, system and equipment of a numerical control grinding machine. According to the method, in a preset historical time period of a to-be-regulated moment, a time sequence curve of the deviation of the grinding power of the numerical control grinding machine relative to the preset grinding power is obtained and subjected to time sequence decomposition, and then proportional gain in PID control parameters is obtained according to the change trend of a trend component and the power deviation at the to-be-regulated moment in the trend component; obtaining an integral gain in the PID control parameters according to the periodic fluctuation characteristics of the seasonal components; according to the change trend of the time sequence curve and the fluctuation characteristics of the residual component, and in combination with the proportional gain and the integral gain, obtaining the differential gain in the PID control parameters; and finally carrying out constant-power grinding control on the numerical control grinding machine. The PID control parameters are adaptively adjusted based on the time sequence decomposition result of the power deviation, and the constant power control effect on the numerical control grinding machine is improved.

A method for Field Oriented Control (FOC) of a Permanent Magnet Synchronous Motor (PMSM) with a constant Power Factor Control (PFC) Loop includes measuring a rotor position of the PMSM. A plurality of stator voltages of the PMSM is controlled with a required direct (d)-axis current, a required quadrature (q)-axis current, the rotor position and a plurality of measured stator currents of the PMSM in a three-phase stationary reference frame. The required d-axis current is determined with a required power factor, the plurality of measured stator currents transformed into two-phase stationary reference frame, the measured stator currents transformed into a rotational reference frame, and each of a required α-axis voltage and a required β-axis voltage transformed into the two-phase stationary reference frame, wherein a power factor of the PMSM is controlled to be equal to the required power factor.

The invention discloses an MPC-SP-based all-vanadium redox flow battery constant-power charging and discharging control method, which is applied to an energy storage control system composed of an MPC-SP controller, a PCS and an all-vanadium redox flow battery, and is characterized in that the controller dynamically and accurately adjusts the power output to the battery based on preset SOC interval division, and the power output to the battery is increased along with the increase of the actual SOC value of the battery. The power is increased in stages. Meanwhile, the controller pays attention to the voltage Ud of the battery end all the time, and when the Ud reaches a voltage limiting value, the constant voltage mode is switched, so that the battery is effectively prevented from being damaged due to overhigh voltage. The state-based dynamic power management is much safer, more flexible and more intelligent than traditional fixed constant power control. According to the invention, the change rate of current in the charge-discharge process of the all-vanadium redox flow battery can be reduced, the service life of the battery is prolonged, and the safety is guaranteed.

The invention discloses a virtual impedance compensation-based active-disturbance-rejection control method for a dual-active-bridge converter, and the method comprises the following steps: firstly designing a virtual impedance compensation strategy, connecting an equivalent virtual conductor in parallel with an output capacitor, converting the equivalent virtual conductor into a duty ratio injection amount, and achieving the active counteracting of the negative impedance of a constant-power load and the reconstruction of the damping of a port; an unstable pole of the right half plane is made to move back to the left half plane, and extra power loss is not introduced; an active disturbance rejection control strategy based on virtual impedance compensation is designed, residual uncertainty after virtual impedance compensation is uniformly regarded as total disturbance online observation and feedforward offset, and therefore rapid and smooth voltage tracking is kept under parameter perturbation and external disturbance. Under the working conditions of voltage reference step and load abrupt change, the improved active disturbance rejection control strategy realizes the effects of no overshoot, shortest setting time and minimum oscillation by enhancing disturbance observation and virtual impedance compensation, and has better damping and disturbance rejection performance.

The invention relates to the technical field of micro-grids, and discloses a control method of a distributed power supply in a plant micro-grid, and the method comprises the steps: S1, constructing a multi-source collaborative micro-grid system; s2, executing real-time power dynamic allocation; s3, working condition power balance control; s4, active regulation of bidirectional power flow and the like. Based on a real-time AGC instruction and plant load data, a hierarchical coordination mechanism is adopted, charging and discharging power is dynamically adjusted by means of stored energy to track the AGC instruction, and constant power output of wind power is maintained in combination with a wind power prediction model; when a thermal power generating unit is subjected to deep peak regulation, shutdown or fault, the system absorbs excess wind power through energy storage charging, synergistically improves the hydrogen production load power, guarantees dynamic matching of the load and power generation, and actively adjusts energy storage charging and discharging and hydrogen production loads by monitoring the power flow directions of a thermal power generating unit section and a desulfurization section in real time according to voltage fluctuation caused by bidirectional power flow. And the voltage deviation is dynamically compensated, and the system voltage stability is greatly improved.

The invention provides a load tracking control method for an energy storage system in an oil field scene, which realizes cooperative control of constant-power operation of a generator and rapid compensation of energy storage. The system comprises the following mechanisms: a diesel generator; the energy storage system comprises an energy storage converter PCS and an energy storage battery pack; the AI sampling module is used for respectively sampling implementation voltage and current data of the diesel generator and the load through a voltage transformer PT and a current transformer CT; the EMS system side power calculation module comprises an energy management system power calculation module and a power conversion system; and an oil field load; an output end of a diesel generator and an output end of an energy storage converter PCS are converged to a load output line and then are connected to an oil field load, an AI sampling module also samples voltage and current data of the load output line, the diesel generator and an energy storage system supply power to the oil field load at the same time, and an engine operates in a high-efficiency interval. And the energy storage system bears instantaneous power fluctuation.

The invention belongs to the technical field of remote plasma sources, and provides a remote plasma source load impedance disturbance protection control method and device. The method comprises the following steps: collecting gas flow, gas pressure and reaction chamber temperature of a reaction chamber; obtaining a load impedance prediction value according to the load impedance prediction model; and controlling the system to work in a constant power stage or a constant current stage according to whether the load impedance predicted value F is in a fluctuation stable interval. According to the method, the load impedance value F can be predicted by using the load impedance prediction model under different gas flows, pressures and cavity temperatures, whether the working state is stable or not is determined according to the load impedance value, and the system is controlled to work in a constant power stage or a constant current stage. Gas load fluctuation and plasma dynamic real-time cooperative regulation and control are achieved, mixing disturbance during gas switching is effectively restrained, and the problem of plasma instability is solved; the situation that a power device is damaged due to overlarge current caused by gas load fluctuation is avoided, and the service life of the remote plasma source is prolonged.

The invention discloses a grid-connected inverter power and current coordination control method under a harmonic power grid and a related device, and relates to the technical field of renewable energy power generation, and the method comprises the steps: obtaining a two-phase power grid AC voltage based on a three-phase power grid AC voltage; calculating a reference current under a direct power control strategy based on the active power reference value, the reactive power reference value and the two-phase power grid AC voltage; harmonic waves in the reference current under the direct power control strategy are filtered out, and a fundamental component and a harmonic component are obtained; based on a preset adjustment coefficient, the fundamental component and the harmonic component, obtaining a reference current with an adjustable harmonic content; performing zero static error control on the reference current with the adjustable harmonic content to obtain a modulation voltage; and performing sine pulse width modulation on the modulation voltage to obtain a grid-connected current. According to the invention, coordinated control of power constancy and current balance of the grid-connected inverter can be realized.

The invention relates to an electric heat tracing type liquid cargo conveying hose which is composed of an inner layer, an outer layer and an electric heat tracing layer between the inner layer and the outer layer, the inner layer is composed of an inner rubber layer, a pressure-bearing framework and a static electricity conducting copper wire, the pressure-bearing framework is arranged between the inner rubber layer and the electric heat tracing layer, and the static electricity conducting copper wire is arranged on the pressure-bearing framework; the electric heat tracing layer is composed of heat tracing cables and filler, the heat tracing cables are spirally wound in the pipe body, and the filler is filled between the heat tracing cables after the heat tracing cables are wound and fixed; the outer layer is composed of a protective adhesive tape layer and an outer adhesive layer arranged outside the protective adhesive tape layer. The constant-power heat tracing cable is wound in the pipe wall, when liquid is conveyed, the hose is heated through the heat tracing cable, a certain temperature is kept in the pipeline, and the condensation phenomenon occurring when the liquid is conveyed in a low-temperature environment is prevented.

The invention relates to the field of UHPC stirring machine control, in particular to a constant-power automatic speed regulation control system and method for UHPC stirring, the operation process of a UHPC stirring machine is divided into a plurality of process stages, each stage corresponds to different frequencies, rotating speeds and operation time, accurate control over the rotating speeds is achieved, and on the premise that the power is constant, the speed regulation speed of the UHPC stirring machine can be accurately controlled. The rotating speed is flexibly adjusted to meet the requirements of different stirring stages of UHPC, the mixing quality is guaranteed, efficient utilization of energy is achieved, a constant-speed stirring machine is changed into a variable-speed intelligent stirring machine through multi-section speed control of the frequency converter, energy is saved by 30% or above, and the quality and productivity of UHPC products are remarkably improved through process-level rotating speed matching.

The invention discloses a high-power stepless magnetic damping device and a power control method thereof.The high-power stepless magnetic damping device comprises a magnetic resistance magnetic core mechanism, the magnetic resistance magnetic core mechanism achieves control over high-power stepless magnetic damping according to the electromagnetic damping principle, regulation and control response is fast, continuity of constant-power output is guaranteed, and the high-power stepless magnetic damping device is suitable for large-power stepless magnetic damping. And a circle of Halbach magnet array formed by reinforcing magnets is arranged, so that the field intensity in the unit direction is enhanced, and the generation of high-power magnetic damping is realized. According to the power control method, a static Kalman data fusion updating model is introduced for power updating, speed and accuracy are balanced, a PWM signal is output through a PID controller to adjust the input current of a control coil, and therefore the size of a magnetic field is controlled, control over the size of magnetic damping is achieved, stepless regulation and control are achieved, and the control precision is improved. Therefore, stable output of constant power is ensured.

The invention discloses an MMC pre-charging method based on bridge arm module alternate bypass. The method comprises the following steps: detecting the voltage of a grid-connected point at the AC side of an MMC; detecting a medium-voltage energy storage unit and a low-voltage energy storage unit, and selecting an energy storage unit participating in MMC pre-charging and a corresponding control mode according to a detection result; controlling a DC bus voltage in the DC power distribution system to be raised to a rated value of a capacitor voltage of an MMC bridge arm sub-module, and executing an MMC pre-charging mode; on the premise that the voltage fluctuation amplitude of the direct-current bus does not exceed the allowable range, different sub-modules on the same bridge arm of the MMC are bypassed alternately in sequence until the difference value between the capacitor voltage of the bridge arm sub-module and the rated working voltage of the bridge arm sub-module is within the allowable range; and closing a circuit breaker at the AC side of the MMC, unlocking the MMC, switching the pre-charging mode of the MMC to a normal operation mode, executing constant DC voltage control by the MMC, and recovering the determined control mode of the energy storage unit to a constant power control mode.

The invention relates to the field of power grids, in particular to a safe constant-power control method for a micro-grid under false information injection attack. The method comprises the following steps: firstly, establishing a micro-grid distributed power supply model, and establishing a dynamic model for describing a distributed power supply inverter in a constant power control mode according to the power supply model; and then, analyzing false information injection attacks, modeling damage of the false information injection attacks to the micro-grid distributed power supply model, and designing an extended state observer to observe damaged information. Finally, designing a sliding mode controller and setting controller parameters; and enabling the micro-grid distributed power supply to stably track the reference power of the energy management system based on the controller. According to the invention, by providing an innovative false information injection attack protection scheme, the constant power control of the micro-grid is optimized, the safety and stability of the system are remarkably improved, and the method is of great significance to the construction, operation and maintenance of an intelligent power grid.

The present application relates to an automatic temperature-controlled air disturbance constant-power charging energy storage system for aqueous liquid-rich batteries, the system comprising: an air disturbance unit for delivering gas to the interior of the battery, the air disturbance unit comprising an air duct, the air duct being vertically inserted into the battery and having a plurality of air holes on its surface for injecting gas into the electrolyte of the battery in the form of bubbles, a temperature regulating unit for regulating the temperature of the gas input to the battery by the air disturbance unit, a collection module for collecting the electrical parameters and temperature parameters of the battery, a control unit for controlling the start and stop of the air disturbance unit, as well as the gas pressure and gas flow rate input to the battery according to the electrical parameters, and controlling the temperature regulating unit according to the temperature parameters. Through the present application, the problems of low charging efficiency and short service life of aqueous liquid-rich batteries are solved. By controlling the temperature of the input gas, the battery temperature is kept within an appropriate range, thereby improving the charging efficiency of the battery, and the air disturbance unit is used to avoid electrolyte stratification, thereby extending the service life of the battery.

The invention discloses a negative electrode tab cover plate laser welding method which comprises the following steps: attaching a tab to a to-be-welded piece, and welding two layers by adopting a spiral welding track; the whole track of the tab is spirally welded on the first layer, and variable power welding is adopted as the first layer spiral welding power; the first one-fifth track of the tab is rewelded on the second layer in a spiral mode, and constant-power welding is adopted as the second layer in spiral welding power. The spiral track can provide a continuous and smooth movement path, the stable welding speed can be kept, the welding efficiency is improved through the stability, and due to the fact that the laser welding head does not need to be started and stopped frequently, the non-production time is shortened; the same welding mark is welded twice in total, the first layer is welded with the whole track, the second layer is welded with the first one-fifth part, the two layers of welding tracks are different in spiral line density, and the second layer mainly aims at modifying the welding appearance and at the same time, the welding temperature is low when welding is just started, and the risk that the front end is not fused is caused; and the abnormity can be solved by re-welding the front part.

The invention belongs to the field of space electric propulsion, and particularly relates to a working medium-free cathode heating method, which comprises the following steps: heating a working medium-free cathode by adopting a constant voltage mode and a constant power mode, dividing the heating process into a plurality of stages, calculating the heating voltage according to the expected power of each stage, and heating for a period of time under corresponding heating; after multi-stage constant-voltage heating is completed, a constant-power heating mode is switched to, the working-medium-free cathode heating voltage is adjusted, and the adjusted working-medium-free cathode heating power is made to be equal to the set rated heating power; according to the method, the thermal instability of working medium-free cathode heating can be effectively reduced, and the working performance of the cathode is enhanced; in the constant-power heating mode, as the input heating power is always a constant value, the temperature of the working-medium-free cathode tends to be stable due to the zeroth law of thermodynamics, namely the thermal equilibrium law, as time goes on, and then thermal instability and noise caused by the thermal performance of the working-medium-free cathode are reduced.