40 results about "Flux density distribution" patented technology

The invention discloses a method for obtaining three-dimensional neutron flux density distribution in a reactor core transient process of a fast neutron reactor. A polygonal prism grid is adopted for the anisotropic neutron flux density of the reactor core of the fast neutron reactor to carry out fully-three-dimensional transportation space dispersion, a semi-spherical surface of a sixty-degree region is taken as a unit to carry out alternate scanning, and iterative format degradation in an angle parallel process is weakened; and the characteristics of the weak local effect and the global space coupling of the neutron flux density of the reactor core of the fast neutron reactor are considered, an estimated correction quasi-static strategy is adopted for neutron flux density change in a transient process to carry out time dispersion, ingredients of different change rates along with time in the neutron flux density can be decomposed, separated solution is carried out on different time scales, meanwhile, nonlinear iteration among above ingredients is avoided, and calculation efficiency is improved. The method for obtaining the three-dimensional neutron flux density distribution in the reactor core transient process of the fast neutron reactor has the advantages of being high in calculation accuracy and reasonable in calculated amount.

The invention relates to an electric machine, particularly for a synchronous machine excited by a permanent magnet. The electric machine comprises a rotor arrangement (4) having buried permanent magnets (6) and a stator arrangement (2) having an inner recess (3) for rotationally movably receiving the rotor arrangement (4), the rotor arrangement (4) comprising a plurality of rotor segments (7), each having a pole shoe (10), the outer contour thereof corresponding to an arc contour having a contour radius, the contour radius being smaller than the radius of the rotor arrangement (4), thus forming a gap between two adjacent rotor segments (7), the at least one outer contour of one of the rotor segments (7) having an arc contour designed such that an air gap length ratio of the radial spacingbetween the inner recess (3) and the outer contour along a radial outer boundary of the corresponding rotor segment and the radial spacing between the inner recess and the outer contour along a radial center axis of the corresponding rotor segment (7) is optimized with regard to the distortion factor of the course of the flux density distribution of the pole shoe (10).

A synchronous permanent magnet machine includes a permanent magnet arrangement for producing a magnetic field having a flux density distribution that is approximately sinusoidal. The permanent magnet arrangement includes a permanent magnet pole with both low and high energy-product magnets. The permanent magnet pole includes a low energy-product magnet and a high energy-product magnet which have different directions of magnetization, or a disposition of low / high energy-product magnets within the permanent magnet pole is asymmetric with respect to the central region of the permanent magnet pole.

A lens driving apparatus for a lens includes a voice coil motor. A coil position of a coil is detected. A table memory stores a correction factor for each one of plural values of the coil position according to flux density distribution. The correction factor is read from the table memory according to the detected coil position. A coil current is corrected by use of the correction factor for each coil position. The corrected coil current is caused to flow through the coil, with which the lens is moved together along an optical axis. Consequently, changes in a moving speed of the lens can be prevented.

The invention discloses a demagnetization detection apparatus and detection method of a permanent magnet synchronous linear motor. The demagnetization detection apparatus of a permanent magnet synchronous linear motor is characterized in that a linear motor with a demagnetization detection apparatus is used as a detection motor; the demagnetization detection apparatus takes an aluminium block as apedestal; a gaussmeter probe is fixedly arranged on the aluminium block by means of a clamp, so that the probe is arranged in the space air gap of the linear motor to be detected; adjusting bolts areused to adjust the positions of three detection points of the gaussmeter probe in space air gap of the linear motor to be detected; and the demagnetization detection apparatus is used for detecting distribution of air-gap flux density at the positions of the three detection points of the linear motor to be detected so as to realize demagnetization detection. The demagnetization detection apparatus and detection method of a permanent magnet synchronous linear motor can determine the difference distribution between the flux density to be detected and normal flux density distribution, and can extract the demagnetization fault characteristics. The demagnetization detection apparatus and detection method of a permanent magnet synchronous linear motor can realize accurate identification of thedemagnetization fault by means of a PNN classification algorithm.

The invention discloses a solar light condensed heat collector and a method for designing the solar light condensed heat collector. A paraboloid main reflector is arranged. A vacuum heat collecting pipe is installed on the symmetrical axis of the cross section of the paraboloid main reflector and on the inner side of the focal line of the paraboloid main reflector. An even light reflector is installed on the outer side of the focal line of the paraboloid main reflector. The even light reflector and an opening of the paraboloid main reflector are oppositely arranged and fixedly connected. According to the solar light condensed heat collector and the method for designing the solar light condensed heat collector, the vacuum heat collecting pipe is arranged below the position of the focal line of the paraboloid main reflector, the even light reflector is additionally arranged and opposite to the opening of the paraboloid main reflector, solar radiation energy can be distributed at the bottom and the top of a heat absorption pipe, solar energy flux density distribution on the wall face of the heat absorption pipe is homogenized, the temperature gradient and the highest temperature of the wall face of the heat absorption pipe are reduced, a series of problems caused by uneven energy flux density can be avoided from the source, and safety performance of the vacuum heat collecting pipe is improved.

The invention discloses a light spot thermal flux density distribution test system. The light spot thermal flux density distribution test system comprises a ceramic installation base, a plurality of temperature sensors, an input and output module, a data processing module, a data display module, a rear end cover plate, a top plate, a bottom plate, a middle supporting plate, two side plates, a speed reducer and a drive motor, wherein one end of the ceramic installation base is fixed to the position of a circular hole in a front end cover plate, the other end of the ceramic installation base is connected with a rotating shaft, the temperature sensors are distributed on the test installation face of the ceramic installation base, the rear end cover plate is provided with the speed reducer, a circular hole used for allowing the rotating shaft to penetrate through is formed in the middle of the middle supporting plate, the other end of the rotating shaft is connected with the speed reducer, the drive motor is arranged on the speed reducer, the drive motor drives the speed reducer to rotate, and rotation is delivered to the rotating shaft so that the ceramic installation base can be driven to rotate. The light spot thermal flux density distribution test system can test whether the thermal flux density distribution of light spots on a whole section is even or not, and the phenomenon that when light spot thermal flux density distribution is not even due to condenser system errors, a hot end part of a thermal absorber is burnt, and even a working medium leaks or explodes is avoided.

A permanent magnet motor has rotor structure that includes magnetically permeable backing material attached to magnets for enhancing flux density distribution. A plurality of permanent magnets are circumferentially distributed about an axis of rotation, adjacent magnets successively alternating in magnetic polarity. The magnetically permeable material is configured with apertures therethrough at areas of low flux density, such as at central portions of the magnets, while in contact with perimeter areas of the magnets. Additional apertures in the material may be located at spaced intersections at which no significant flux density exists. The apertures may be replaced with backing material portions of reduced radial thickness.

The invention provides a dry calibration method and the device for the portable electromagnetic flow meter. The device comprises a measuring paper which is arranged with hall sensor array, a measuring control module and a portable computer. The measuring paper is pasted to the inner wall of the electromagnetic flow meter pipe. The computer controls the measuring paper through the measuring control module to obtain the normal flux density distribution information of the pipe inner wall, and furthermore, combining with the geometries of the electrode and the pipe and the flow rate distribution information, and by using the computer program compiled based on dry calibration methematical model, the once sensor conversion coefficient can be calculated, and so the once sensor dry calibration of the electromagnetic flow meter can be realized. The size of the measuring paper can be adjusted by cutting or assembling, which leads that the device can be applied in the electromagnetic flow meter with different size. The device removes the complicate point-by-point scanning process and the bulky driving mechanism in the prior point-by-point typed dry calibration device, which makes the calibration rate improve greatly. The device is quite light and convenient, and is a portable dry calibration device for the electromagnetic flow meter.

A lens driving apparatus for a lens includes a voice coil motor. A coil position of a coil is detected. A table memory stores a correction factor for each one of plural values of the coil position according to flux density distribution. The correction factor is read from the table memory according to the detected coil position. A coil current is corrected by use of the correction factor for each coil position. The corrected coil current is caused to flow through the coil, with which the lens is moved together along an optical axis. Consequently, changes in a moving speed of the lens can be prevented.

An apparatus for sensing a position of an object is provided that may include a magnet having a set of magnetic flux properties, the magnet mounted for movement about an axis relative to the object and a magnetic field-sensing device mounted in fixed relation to and spaced from the magnet, the magnetic field-sensing device calibrated to sense a change in at least one magnetic flux property in response to movement of the magnet relative to the object and generate a data signal indicative of a position of the object. In one aspect the magnet is configured to have a substantially diamond shaped cross section and the magnetic field-sensing device is calibrated to sense a change in flux density distribution in response to a change in an air gap defined between an exterior surface of the magnet and the magnetic field-sensing device.

A synchronous permanent magnet machine includes a permanent magnet arrangement for producing a magnetic field having a flux density distribution that is approximately sinusoidal. The permanent magnet arrangement includes a permanent magnet pole with both low and high energy-product magnets. The permanent magnet pole includes a low energy-product magnet and a high energy-product magnet which have different directions of magnetization, or a disposition of low / high energy-product magnets within the permanent magnet pole is asymmetric with respect to the central region of the permanent magnet pole.

A developing device includes a first magnet fixed inside a first developer bearing member and including a pair of first repulsion magnetic poles with the same polarity and disposed adjacent to each other, and a second magnet fixed inside a second developer bearing member and including a pair of second repulsion magnetic poles with the same polarity and disposed adjacent to each other. The first magnet has a magnetic flux density distribution of a normal component of the first developer bearing member in the circumferential direction of the first developer bearing member having only one minimal point between the pair of first repulsion magnetic poles, and the second magnet has a magnetic flux density distribution of a normal component of the second developer bearing member in the circumferential direction of the second developer bearing member having a plurality of minimal points between the pair of second repulsion magnetic poles.

The invention provides a method for finding an influence rule on torques and harmonic waves by negative sequence components in a steam-turbine generator and particularly relates to calculation of influences on the torques and the harmonic waves by a magnetic field generated by negative sequence current components, aiming at solving the problem that the heat stability of a motor is reduced, caused by the fact that a rotor of the large-size steam-turbine generator is restricted by the negative sequence components. The method comprises the following steps: step 1, establishing a steam-turbine generator model; step 2, analyzing the influences on the torques by the different negative sequence components; step 3, analyzing the influences on gap flux density harmonic waves by the changes of the different negative sequence components; and step 4, analyzing the influences on flux density distribution when the negative sequence components are changed. According to the method provided by the invention, simulating calculation can be carried out through the steam-turbine generator under the condition that the negative sequence current components are different, and the torques are calculated and analyzed under a negative sequence operating working condition; and regular changes of the gap flux density harmonic waves of the generator are concluded and analyzed.

A stator punched plate of a single-phase direct current brushless motor comprises a stator punched plate body and is characterized in that the inner arc of the stator punched plate body is in a step tooth shape, an asymmetrical continuous arc shape or an eccentric circular arc shape, the circular arc of the inner arc is transited by an offset circular arc, the offset direction is directed to a corresponding stator tooth portion, the radius of the offset circular arc is R, the radius of the stator inner arc before offset is R0, the center of a circle offset circle radius of the offset circular arc is r, the circle center offset angle of the offset circular arc with a central axis serving as a basic reference is alpha, the offset distance of the intersection point between the offset circular arc and the stator tooth central axis of the stator punched plate is e, the relations among the R, the R0, the r, the alpha and the e conform to a cosine law, and the radius of the offset circular arc can be determined. According to the stator punched plate of the single-phase direct current brushless motor, an optimized stator punching inner arc structure is utilized, the flux density distribution in air gaps of the punching structure which is a step tooth shape and a continuous arc shape tooth is rearranged, the flux density transition tends to be even, the starting torque is improved by about 14.48%, the average output torque is improved by 0.6%, the torque pulsation is decreased by 2.1%, the electromagnetic noise and vibration of a motor are improved, and the efficiency of the motor is increased.

The invention belongs to the technical field of flat wire motors, and particularly relates to a same-slot-layer multi-wire stator assembly and a flat wire motor. The stator assembly comprises a stator core and a stator winding. The stator iron core is roughly in a cylindrical shape; the stator core is provided with a plurality of stator grooves, and each stator groove is internally provided with a plurality of combined conductor layer groups. Compared with the prior art, the stator assembly provided by the invention has the advantages that the length-width ratio of each rectangular conductor is reduced under the condition of ensuring that the total sectional areas of the conductors in the stator grooves are similar, so that U-shaped wire forming is facilitated, and the manufacturability is better; and meanwhile, the length and width of each rectangular conductor in the stator slots are adjusted, the stator slot types are adjusted, the stator tooth parts are utilized, the radial distance of the stator slots is adjusted, the inner diameter of the stator is adjusted, and the stator yoke parts are adjusted, so that the flux density distribution of each part of the stator assembly is reasonable, the slot fullness rate is improved, and the working efficiency of the motor is improved.

The invention discloses a rapid calculation method for PWM harmonic loss of a permanent magnet motor. The method comprises the steps of firstly, adopting the static finite element calculation to obtain the flux density distribution in a permanent magnet motor silicon steel sheet; then constructing a permanent magnet motor alternating current small signal model based on a freezing increment tensormagnetoresistance method, calculating the loss factors on a stator and a rotor under the respectively excitation of the d-axis and q-axis high-frequency harmonic voltages by adopting a frequency domain finite element method, and calculating the PWM harmonic iron loss on the stator and the rotor quickly by directly utilizing the PWM voltage frequency spectrums on the stator and the rotor respectively; and finally, fitting the change relationship of the eddy current loss factors along with a fundamental current through a quadratic polynomial to realize the rapid calculation of the PWM harmonic iron loss of the permanent magnet motor in a whole working range. The method overcomes the defect of high time consumption in the prior art, and has both accuracy and rapidity.

The invention relates to an electric machine, particularly for a synchronous machine excited by a permanent magnet. The electric machine comprises a rotor arrangement (4) having buried permanent magnets (6) and a stator arrangement (2) having an inner recess (3) for rotationally movably receiving the rotor arrangement (4), the rotor arrangement (4) comprising a plurality of rotor segments (7), each having a pole shoe (10), the outer contour thereof corresponding to an arc contour having a contour radius, the contour radius being smaller than the radius of the rotor arrangement (4), thus forming a gap between two adjacent rotor segments (7), the at least one outer contour of one of the rotor segments (7) having an arc contour designed such that an air gap length ratio of the radial spacing between the inner recess (3) and the outer contour along a radial outer boundary of the corresponding rotor segment and the radial spacing between the inner recess and the outer contour along a radial center axis of the corresponding rotor segment (7) is optimized with regard to the distortion factor of the course of the flux density distribution of the pole shoe (10).

The invention provides a rotor structure, a motor and a household electrical appliance. The rotor structure is used for an alternating pole motor. The rotor structure comprises permanent magnetic poles, alternating poles and air grooves; the air grooves are formed in the permanent magnetic poles and / or the alternating poles; and the air grooves are used for increasing the gap flux density of the permanent magnetic poles and / or the alternating poles. According to the rotor structure, the motor and the household electrical appliance of the invention, the air grooves are formed in the permanent magnetic poles and / or the alternating poles, so that flux density distribution in the magnetic poles is optimized, and gap flux density at the magnetic poles is increased, and therefore, the torque ofthe motor is improved; with the air grooves adopted, the flux density waveforms of the rotor are optimized, and therefore, the flux density waveforms of the rotor tend to be sinusoidal, the torque pulsation of the motor is reduced, and the vibration and noise of the motor are reduced.

The invention discloses a near-field magnetic localization method for a circular ring magnet. The method includes the steps that a magnetic field distribution integral model of the circular ring magnet is built in a magnet coordinate system OXYZ, and then the magnetic field distribution integral model of the circular ring magnet is used for obtaining the magnetic flux density vector generated by the circular ring magnet at the space point on the plane YOZ; the value of the magnetic flux density vector generated at any space point around the circular ring magnet in the magnet coordinate system OXYZ is calculated; a magnetic doublet magnetic flux density distribution model is used for calculating respective initial values of six pose parameters of the circular ring magnet in a word coordinate system; the magnet coordinate system OXYZ is built in the word coordinate system according to the initial values of six pose parameters of the circular ring magnet in the word coordinate system, and the respective final values of the six pose parameters of the circular ring magnet in the word coordinate system are obtained. The near-field magnetic localization method has the advantages that location precision is high during near-field magnetic localization, and calculation complexity of magnetic flux density is reduced.

The invention discloses a stator punching of a single-phase capacitor-run motor. The center of the stator punching is provided with a hollow inner round hole; a plurality of winding slots are arranged along the radial direction of the stator punching; a stator tooth is formed between the adjacent winding slots; a salient pole is formed at the end part of each stator tooth; and the salient poles are evenly distributed towards the edge of the hollow inner round hole. The dimensions of the stator punching are shown as follows: the diameter of the excircle of the stator punching is 88.00-88.03mm; the diameter of the hollow inner round hole is 50.00-50.046mm; the stator teeth are parallel teeth and are 4.9-5.1mm wide and 6.85-6.95mm high; the notch of each winding slot is 1.80-1.85mm wide; notches are 0.48-0.52mm high; slot shoulders are 0.75-0.85mm high; and the diameter of a circle on which slot bases are located is 66.30-66.50mm. According to the stator punching disclosed by the invention, as a brand-new inner diameter, outer diameter and groove dimensional design is adopted, flux density distribution of all parts in a magnetic circuit are fully matched, so that the energy efficiency of the motor is improved by 5-10 percent. Meanwhile, the demand of enameled wires and steel products of the single-phase capacitor-run motor is 7-10 percent lower than that of motors with the same power level as the single-phase capacitor-run motor. The stator punching of the single-phase capacitor-run motor is excellent in performance and is convenient for serving as the stator punching for high-power split air conditioner internal units.

The invention discloses a rotor punching sheet for an outer rotor motor of a household electric appliance fan, and the punching sheet comprises a punching sheet body, wherein the surface of the punching sheet body is provided with an inner circular hole and punching sheet slots. The periphery of the inner circular hole is uniformly provided with the punching sheet slots, and each punching sheet slot comprises a notch, a slot shoulder and a slot body, wherein the notch is a rectangular hole, the slot shoulder is a trapezoid hole, the slot shoulder is communicated with the notch and the slot body is a trapezoid hole. The inner circular hole is communicated with the slot shoulders through the slot bodies. The punching sheet employs a flat bottom groove shape, increases the area of the punching sheet slots, improves the quality of aluminium casting of a rotor, and achieves the effect of improving the noise. The flux density distribution of a tooth part of the motor rotor is enabled to be more reasonable, and the collocation of the flux density of the rotor punching sheet and a stator punching sheet is more reasonable. The motor efficiency is improved, and the loss of copper or aluminium is also reduced during the manufacturing of the motor, and the consumption of the raw materials of a winding and an iron core is reduced.

A stator punching plate used for an air conditioning fan motor relates to the technical field of AC asynchronous motor modification, and is characterized by comprising an annular punching plate body, wherein the middle part of the punching plate body is provided with a hollow inner round hole and an outer circle, a punching plate groove is arranged between the outer circle of the punching plate body and the hollow inner round hole, the punching plate groove is provided with a notch, a groove shoulder, a groove body and a groove top. The stator punching plate provided by the invention has the advantages that the structure is reasonable, the flux density distribution of iron cores is effectively improved, the raw material consumption of coils and the iron cores is reduced, the energy efficiency is high and the service life is long.

The invention discloses a near-field magnetic localization method for a circular ring magnet. The method includes the steps that a magnetic field distribution integral model of the circular ring magnet is built in a magnet coordinate system OXYZ, and then the magnetic field distribution integral model of the circular ring magnet is used for obtaining the magnetic flux density vector generated by the circular ring magnet at the space point on the plane YOZ; the value of the magnetic flux density vector generated at any space point around the circular ring magnet in the magnet coordinate system OXYZ is calculated; a magnetic doublet magnetic flux density distribution model is used for calculating respective initial values of six pose parameters of the circular ring magnet in a word coordinate system; the magnet coordinate system OXYZ is built in the word coordinate system according to the initial values of six pose parameters of the circular ring magnet in the word coordinate system, and the respective final values of the six pose parameters of the circular ring magnet in the word coordinate system are obtained. The near-field magnetic localization method has the advantages that location precision is high during near-field magnetic localization, and calculation complexity of magnetic flux density is reduced.

The invention discloses a non-uniform geometrical variational nodal method aiming at a reactor neutron diffusion equation. The method comprises the following steps: 1, establishing a functional containing a neutron conservation relationship inside the nodal block and flow continuity conditions on the nodal surface; 2, performing nodal discrete disposal by utilizing a finite element shape function in the x-y direction and a chip constant polynomial, and realizing non-uniform nodal geometrical and material description functions; 3, deducing to obtain a response matrix equation; and 4, solving the response matrix equation by utilizing a red-black scanning manner, and finally obtaining the neutron-flux density distribution in the whole non-uniform solving area. According to the method disclosed by the invention, the non-uniform lattice-cell structure of a nuclear reactor can be finely described; and according to the method, the nodal internal fine geometrical structure is processed based on the variational nodal method by adopting an isoparametric finite element, and then the non-uniform geometrical neutron diffusion equation is solved.

The invention discloses a tangential four-layer winding fractional slot permanent magnet motor flux density distribution calculation method. The method comprises the following steps: performing equivalence on each magnetic isolation bridge of a permanent magnet motor by using a rectangular equivalent air gap; estimating the saturation degree of the iron core at the magnetic isolation bridge; calculating an equivalent air gap length initial value; dividing a motor region into five types of sub-domains; establishing a vector magnetic potential equation in each sub-domain and a boundary condition on an interface; obtaining a flux density expression of the permanent magnet motor and an error of relative permeability by solving an unknown coefficient in the vector magnetic potential equation; and the relative permeability of the iron core at the magnetic isolation bridge is updated for iterative calculation until the error value of the obtained relative permeability is smaller than a limit value, so that the final flux density result of the permanent magnet motor is obtained. According to the method, the flux density of the permanent magnet motor under the consideration of iron core saturation can be accurately calculated, and an efficient and accurate research method is provided for magnetic field calculation and performance analysis of the tangential four-layer winding fractional slot permanent magnet motor.

The invention provides a method for finding an influence rule on torques and harmonic waves by negative sequence components in a steam-turbine generator and particularly relates to calculation of influences on the torques and the harmonic waves by a magnetic field generated by negative sequence current components, aiming at solving the problem that the heat stability of a motor is reduced, caused by the fact that a rotor of the large-size steam-turbine generator is restricted by the negative sequence components. The method comprises the following steps: step 1, establishing a steam-turbine generator model; step 2, analyzing the influences on the torques by the different negative sequence components; step 3, analyzing the influences on gap flux density harmonic waves by the changes of the different negative sequence components; and step 4, analyzing the influences on flux density distribution when the negative sequence components are changed. According to the method provided by the invention, simulating calculation can be carried out through the steam-turbine generator under the condition that the negative sequence current components are different, and the torques are calculated and analyzed under a negative sequence operating working condition; and regular changes of the gap flux density harmonic waves of the generator are concluded and analyzed.

The invention discloses a stator punching piece, a stator and a compressor. The stator punching piece comprises a punching piece body provided with a rotor hole and three mounting holes; a plurality of wire embedding slots are formed in the inner peripheral wall of the rotor hole; the two mounting holes and one mounting hole are formed in the two sides of the rotor hole respectively; and a plane passing through the center of the mounting hole and the center of the rotor hole is a first plane. The punching piece body is formed by two semi-structure elements that are symmetric relative to the first plane; the outer peripheral wall of each semi-structure element is formed by a first straight line segment, a second straight line segment, a notch part, and an end portion connecting segment; the first straight line segments of the two semi-structure elements and the end portion connecting segments are connected; and the second straight line segments are perpendicular to the first straight line segments. The notch parts include first bevel edges, second bevel edges, and connection segments; and the first bevel edges are parallel to the second bevel edges. According to the stator punching piece, materials can be saved and uniform flux density distribution can be guaranteed.

The invention discloses a light spot thermal flux density distribution test system. The light spot thermal flux density distribution test system comprises a ceramic installation base, a plurality of temperature sensors, an input and output module, a data processing module, a data display module, a rear end cover plate, a top plate, a bottom plate, a middle supporting plate, two side plates, a speed reducer and a drive motor, wherein one end of the ceramic installation base is fixed to the position of a circular hole in a front end cover plate, the other end of the ceramic installation base is connected with a rotating shaft, the temperature sensors are distributed on the test installation face of the ceramic installation base, the rear end cover plate is provided with the speed reducer, a circular hole used for allowing the rotating shaft to penetrate through is formed in the middle of the middle supporting plate, the other end of the rotating shaft is connected with the speed reducer, the drive motor is arranged on the speed reducer, the drive motor drives the speed reducer to rotate, and rotation is delivered to the rotating shaft so that the ceramic installation base can be driven to rotate. The light spot thermal flux density distribution test system can test whether the thermal flux density distribution of light spots on a whole section is even or not, and the phenomenon that when light spot thermal flux density distribution is not even due to condenser system errors, a hot end part of a thermal absorber is burnt, and even a working medium leaks or explodes is avoided.