RU2444802C1 - Device of automatic control of power generator - Google Patents

Abstract

FIELD: electricity. ^ SUBSTANCE: device of automatic control of a power generator comprises a ferromagnetic ring, a part of which is placed into a saturating magnetic field of a strong permanent magnet, equipped with a magnetisation coil, and its other part is connected to a heat-releasing medium, for instance, purified water taken from the appropriate water pool, a three-phase AC generator connected to a three-phase rectifier and to an electric load, a control unit of the magnetisation coil of the strong permanent magnet, a reference voltage generator, a phase-sensitive rectifier and a low-pass filter (or an integrator), a a tacho-generator connected to each other as specified in the invention claims. The magnetic gap of the strong permanent magnet is made of two parts, the first of which forms a uniform magnetic field with intensity providing for maximisation of magnetic response of the ferromagnetic at the length L of this part of the magnetic gap, and the second part of the magnetic gap with the length L generates a saturating magnetic field in the beginning of this part of the magnetic gap and further a magnetic field in direction of movement of the ferromagnetic ring that linearly increases by intensity to the end of the magnetic gap. Angular speed ë* of the ferromagnetic ring rotation corresponding to the maximum value of the rotation torque that occurs in it is determined by the condition ë*=L/Rä, where =1.23 and R - average radius of the ferromagnetic ring, ä - time constant of magnetic viscosity relaxation of the ferromagnetic, from which the ferromagnetic ring is made. The device that does not consume deficit fuel is an environmentally pure power engineering facility, which does not increase a thermal component during its operation, operates successfully in winter time, slightly decreasing its capacity. ^ EFFECT: improved power efficiency of a thermomagnetic converter of thermal energy of environment into mechanical work.

Description

The invention relates to the field of physics and electronics, in particular to systems for automatic stabilization of the frequency of generated electrical oscillations, and can be used as a stabilized AC source that uses environmental thermal energy for its work.

Direct conversion of thermal energy into electrical energy is known based on the Seebeck effect — the occurrence in an electrical circuit consisting of several dissimilar conductors, the contacts between which have different temperatures [1-4], for example, on the basis of a junction of conductors "constantan (-38 μV / K) - chromel (+24 µV / K) ”or compounds of“ bismuth (-68 µV / K) with antimony (+43 µV / K) ”. On the basis of the Seebeck effect, thermoelectric generators have been developed, which include thermopiles composed of semiconductor thermoelements (amorphous or glassy) connected in series or in parallel. The idea of using semiconductor thermocouples, instead of metal thermocouples, belongs to Academician A.F. Ioffe (USSR). However, these devices have not yet found application in the electric power industry for a number of objective reasons.

It is of interest to use thermomagnetic phenomena to obtain mechanical energy, in particular, the magnetocaloric effect in ferromagnets in combination with such well-known properties of ferromagnets as magnetic viscosity, a decrease in magnetic susceptibility in saturating magnetic fields (Stoletov curve), the presence of a first-order phase transition in saturating magnetic fields (with an adequate decrease in the specific heat capacity of the ferromagnet), symmetry breaking in the heating processes during magnetization and cooling at times agnichivanii. The combination of these properties makes it possible to synthesize a parametric thermomagnetic generator of mechanical energy in which a rotating magnetic field is replaced by a rotating distribution of magnetic susceptibility synchronously with a rotating ferromagnetic ring, a small part of which is placed in a stationary saturating magnetic field localized in space (principle of rotation equivalence). In this case, the center of magnetization of a ferromagnet moving inside the magnetic gap in such a constant distribution over time lags behind the center of attraction inside the magnetic gap, as a result of which a constant force arises, the vector of which is directed tangentially to the ferromagnetic ring in the direction of rotation, which supports the indicated rotational motion if the rotational moment is not less than the friction moment and the connected load. In this case, internal thermal energy is expended in the ferromagnetic ring during its demagnetization, which is replenished by the thermal energy of the environment in the heat conduction mechanism.

On the specified combination of the known properties of ferromagnets, the author proposed a method for producing energy and a number of devices based on this method and its modifications [1-7].

The closest analogue of the claimed technical solution (prototype) can be taken "Device for stabilizing the frequency of the generator" [7], previously proposed by the author, containing a permanent magnet with a saturating magnetic field in its gap and placed in this gap a ferromagnetic body of a magnetically viscous substance, made, for example , in the form of two disks with coaxial axes of rotation, the edges of which are placed in the gap of the specified permanent magnet, and the disks are driven into rotational motion by an external single action in mutually opposed in the same directions with equal absolute angular velocities from the alternating voltage source using an engine generator with a freely rotating rotor and a stator mechanically connected with the corresponding rotation axes of the indicated ferromagnetically viscous disks, while the rotor is made on the basis of a permanent magnet, and the stator contains a three-phase winding, outputs which are connected via insulated ring electrodes, a brush holder with three brushes and a two-position three-contact switch, or to an alternating source voltage when the device is put into operation, or to an electric load with variable parameters through a three-phase rectifier - in the mode of generating electric current, while one of the phases of the stator is connected to the input of the electronic frequency meter, characterized in that a stabilized reference voltage generator is connected in series , frequency divider, phase-sensitive rectifier, inertial link, DC amplifier, output connected to the load in the form of a magnetizing winding, made on permanent magnet to change the intensity of the saturating magnetic field in its gap, while the second input of the phase-sensitive rectifier is connected to one of the phases of the stator in the mode of generating electric current, and the power of the introduced electrical circuits is provided from the output of a three-phase rectifier, in addition, an additional current is made on the permanent magnet winding connected in the gap between the output of a three-phase rectifier and the load with variable parameters.

The use in a known device (prototype) of a uniform magnetic field in the gap of a permanent magnet, which is fundamentally important given two ferromagnetic disks rotating in mutually opposite directions, slightly reduces the energy efficiency of the energy generator, since the centers of magnetization and attraction are slightly spaced. In addition, in such a magnetic field there is no tension gradient, which also reduces the energy of the device.

These disadvantages of the known device are eliminated in the claimed technical solution.

The aim of the invention is to increase the energy efficiency of a thermomagnetic converter of thermal energy of the environment into mechanical work.

This goal is achieved in the inventive device for automatic control of an electric generator containing a ferromagnetic ring mechanically connected to the axis of rotation through the yokes, part of the ferromagnetic ring is placed in the saturating magnetic field of a strong permanent magnet equipped with a magnetizing coil, and the other part is connected to a heat-generating medium, for example, purified water taken from the corresponding water basin, a three-phase alternator is mechanically connected to the axis of rotation, connected to the three-phase rectifier and to the electrical load, the output of the three-phase rectifier through the magnetization control unit is connected to the magnetization coil of a strong permanent magnet, the input of the magnetization control unit is connected to the output of a series-connected reference voltage generator, phase-sensitive rectifier and low-pass filter (or integrator), characterized in that a tachogenerator is mechanically connected to the axis of rotation of the ferromagnetic ring, the output of which is connected to the second input of the phase detector rectifier, and the magnetic gap of a strong permanent magnet is made of two parts, the first of which forms a uniform magnetic field with a strength that ensures that the magnetic susceptibility of the ferromagnet is maximized along the length L of this part of the magnetic gap, and the second part of the magnetic gap of length L forms a saturating magnetic field at the beginning of this part of the magnetic gap and further in the direction of motion of the ferromagnetic ring, the magnetic field increases linearly in strength to the end of the magnetic a gap, and the angular velocity ω * of rotation of the ferromagnetic ring, corresponding to the maximum of the rotational moment arising in it, is determined by the condition ω * = L / λRτ, where λ = 1.23 and R is the average radius of the ferromagnetic ring, τ is the relaxation time constant of the magnetic viscosity of the ferromagnet from which the ferromagnetic ring is made.

Achieving the stated objective of the invention is explained, firstly, by preliminary bringing the ferromagnet to its entrance into the second part of the magnetic gap with a saturating magnetic field to its maximum value of magnetic susceptibility, which leads to the appearance of a rapidly developing magnetization jump in the magnetization moving inside the second part of the magnetic gap in its beginning, which shifts the magnetization center of the ferromagnet in this part of the magnetic gap to its beginning, and, secondly, the displacement of the center of attraction nonuniform magnetic field within the second part of the magnetic gap to the end of a linearly increasing magnetic field strength. Both of these effects lead to a significant separation of these centers, which increases the arising force of retraction of the ferromagnetic ring in the second part of the magnetic gap, which is the working part accelerating the ferromagnetic ring. In addition, the presence of a magnetic field gradient also contributes to an increase in this force, which determines the torque applied to the ferromagnetic ring in the direction of its rotation.

In addition, the use of an automatic control system for the magnetization current of a strong permanent magnet makes it possible to stabilize the frequency of the generated oscillations in the electric generator at a load that varies within specified limits by comparing the frequency of the signals from the output of the tachogenerator and the reference voltage generator in a static or astatic control system.

The invention is clear from the scheme shown in Fig. 1, which consists of:

1 - ferromagnetic ring,

2 - a strong permanent magnet with a magnetizing winding,

3 - magnetization coils of a strong permanent magnet 2,

4 - axis of rotation of the ferromagnetic ring 1,

5 - traverse fastening a ferromagnetic ring with its axis of rotation,

6 - tachogenerator, measuring the frequency of rotation of the ferromagnetic ring,

7 - alternator, for example, three-phase,

8 - phase-sensitive rectifier,

9 - low pass filter (or integrator),

10 - magnetization control unit (powerful DC amplifier),

11 - reference voltage generator (with a frequency corresponding to a stabilized frequency of rotation of the axis 4 or the shaft of the electric generator when using a boost gear),

12 - three-phase rectifier (according to the Larionov scheme) with a ripple filter.

The axis of rotation 4 is mechanically connected with the tachogenerator 6 and the alternator 7, which is shown in bold dotted line in Fig. 1. The inflow of thermal energy Q to the ferromagnetic ring is conventionally shown by arrows. A side section of the magnetic gap of the strong permanent magnet 2 is shown together with a part of the ferromagnetic disk 1 in Fig. 2.

Figure 2 shows the direction of motion of the ferromagnetic ring 1 in the magnetic gap of the strong permanent magnet 2 arrow. The broaching speed of a ferromagnet in the magnetic gap is V = ω * R and it corresponds to the maximum rotational moment applied to the ferromagnetic ring from the side of the magnetic field. In the first part of the magnetic gap, a uniform magnetic field with an intensity H * is formed, which ensures that the ferromagnet reaches its maximum magnetic susceptibility χ _MAX , the initial value of which is χ _NACH <χ _MAX , along the length L of this part of the magnetic gap at a speed V of the pulling ferromagnet. A step is made between the first and second parts of the magnetic gap, so that at the beginning of the second part of the magnetic gap of length L, the magnetic field strength H _{O is} selected saturating for the ferromagnet used, and H _O >> H *. In the second part of the magnetic gap (working), an inhomogeneous magnetic field is formed with a linearly increasing intensity and a field gradient along the x axis equal to grad Н _X = (H _MAX- Н _О ) / L, where H _MAX is the magnetic field strength at the end of the magnetic gap.

Figure 3 shows a graph of the magnetic susceptibility χ (x) of a ferromagnet inside both parts of the magnetic gap with a stationary ferromagnetic ring, i.e., in static (at V = 0). It can be seen that the magnetic susceptibility changes sequentially from the initial χ _NACH to the maximum χ _MAX inside the first part of the magnetic gap, and then drops to the minimum χ _MIN inside the second part of the magnetic gap, which is due to the deep saturation of the ferromagnet in this part of the magnetic gap. Upon exiting the magnetic gap, the magnetic susceptibility is again restored to the initial initial value χ _NACH .

Figure 4 shows a graph of the magnetic susceptibility χ (x) of a ferromagnet in the dynamics of motion of a ferromagnetic ring in a magnetic gap. First, in the first part of the magnetic gap, the magnetic susceptibility increases exponentially from its initial value χ _NAV to χ _MAX *, which is slightly less than χ _MAX . Then it exponentially drops in the saturating magnetic field of the second part of the magnetic gap to a minimum value χ _MIN *> χ _MIN , slightly exceeding the value χ _MIN (due to the finite time of the exponential process by the limited length L). The data with an asterisk corresponds to the case of rotation of the axis 4 with an angular velocity ω * = L / λRτ (that is, with the optimum speed of the ferromagnet V = ω * R. The x coordinate is connected with the time coordinate t by the simple relation x = Vt.

Figure 5 shows a graph of the distribution of the magnetization J (t) of a ferromagnet inside the magnetic gap as a function of time t (or, equivalently, as a function of the x coordinate). Since the magnetization is determined by the formula J (x) = µ _О χ (x) Н (x), where µ _О is the previously determined absolute vacuum magnetic permeability [GN / m], then by the end of the first part of the magnetic gap, the magnetization increases to J _NACH * (its initial value at the very beginning of the second part of the magnetic gap), calculated as J _NACH * = µ _О χ _MAX H *. Since at the beginning of the second part of the magnetic gap there is a magnetic field strength Н _О >> Н * (for example, an order of magnitude), and the magnetic susceptibility cannot change abruptly, a sufficiently strong magnetization surge occurs in this part of the magnetic gap, which tends to the value µ _O χ _MAX Н _O , although at the same time a saturating magnetic field acts on the ferromagnet, which prevents the growth of magnetization to the indicated value, and the magnetization of the ferromagnet at the beginning of the second part of the magnetic gap quickly reaches values of J _MAX . Then, the magnetization of the ferromagnet in the saturating magnetic field exponentially decreases, tending to the saturation magnetization J _HAС (∞), but reaches a value slightly exceeding this value, namely, J _HAC (∞) + ΔJ * due to the finiteness of the interval L. The value The saturation magnetization J _HAC (∞) is always greater than the magnetization J _HACH * at the highest magnetic susceptibility χ _MAX several times, which can be denoted as σ = J _HAC (∞) / J _HACH * (usually σ≈2 ... 3). As will be shown below, the magnetization splash front at the boundary of the first and second parts of the magnetic gap has a duration Δt * = - τln [1- (Н * / Н _O )], which is due to a sharp increase in the rate of the exponential process due to the inequality Н _O >> Н *.

Fig. 6 shows a graph for calculating the position of the center of magnetic attraction in an inhomogeneous magnetic field of the second part of the magnetic gap, constructed using the Mathcad program with some changes in the notation of quantities, and also a table of relative positions of this center in the function of the parameter p = (H _MAX- Н _O ) / N _O , the preferred value of which lies in the range p = 5 ... 10. The position of the center of magnetic attraction is in the range (0.66 ... 0.68) L.

Fig. 7 shows a graph for calculating the position of the center of magnetization of a ferromagnet located in the second part of the (working) magnetic gap for one of the specific examples, as well as a table of values of the position of this center as a function of the parameter σ = 2 ... 4. It is seen that the range of positions of the center of magnetization lies within the narrow limits (0.445 ... 0.473) L.

A comparison of the relative (and absolute) positions of the centers of magnetization and magnetic attraction proves that the first from the second ferromagnet in the magnetic gap lags the second along the broach, that is, it explains the nature of the occurrence, the constantly acting forces F (ω) of drawing the ferromagnetic ring into the magnetic gap, as a function of the angular rotational speed ω of the ferromagnetic ring.

Fig. 8 shows the graphs of the retracting forces F (ω) _MAX and F (ω) _MIN at the highest and correspondingly lowest values of the magnetization current of a strong permanent magnet 2 (Fig. 1) in coil 3, as well as the corresponding load direct feedback, expressed at load moments, respectively, M _{N MAX} and M _{H MIN} . From the theory of automatic control it is known that at the intersection points of these pairs of graphs with different signs of derivatives, a stable rotation mode is ensured.

That is why, in order to keep the rotational speed of the ferromagnetic ring in a fairly narrow range, that is, with a minimum permissible deviation from the operating frequency (for example, 50 Hz), the claimed technical solution uses an electronic automatic control system for a given model signal from the output of the reference voltage generator 11 As mentioned above, the maximum torque is achieved at an angular velocity of rotation ω *, although the working frequency range is ω> ω *, and the working section is selected on the falling side power characteristics F (ω). With an increase in the load, the rotational speed of the axis 4 decreases somewhat within the permissible values, and when the load decreases, on the contrary, it increases slightly, as can be seen from the graphs.

In Fig. 9, in a relative representation, the graphs of the net power on the rotation axis 4 are given, respectively, for the largest and smallest loads - P _MAX and P _MIN in a frequency-stabilized zone of width Δω, which is small compared to ω, i.e., we have the stabilization condition Δω / ω << 1 in the entire range of working loads on the generator 7.

Figure 10 shows a diagram of the design of the device with the combination of several modules of ferromagnetic disks with their strong permanent magnets (with magnetization coils and a magnetization control unit 10 common to all modules) connected to a single axis of rotation, in order to increase the net power delivered to the load 7. For each ferromagnetic ring (or disk), this design has two strong permanent magnets, instead of one, which improves the energy efficiency of the device. CTBA power generation. In this case, the heating time of the ferromagnet is halved, which reduces the power of the device in comparison with its twofold increase due to a pair of magnets on one ferromagnetic ring (or disk). In this device, a common housing 13 is used, in which there is flowing purified water 14, supplied by means of a pump 15 equipped with a water purification filter taken from any reservoir (water can flow by itself if there is a difference in the levels of water intake and its discharge). All ferromagnetic rings (or disks) 1 are mechanically connected to a single axis of rotation 4, which is connected through an up-converter 16 to an alternator 7 and a tachogenerator 6 (not shown in Fig. 10). An autonomous heating system for ferromagnetic rings (or disks) is possible due to the use of a radiator for heating the liquid circulating in the housing 13 in a closed cycle. In addition to the radiator, the housing 13 is made of finned metal rings with a developed surface, which also contributes to the transfer of thermal energy from the external environment to the circulating fluid. Direct contact of the heating fluid with ferromagnetic rings (or disks) increases the rate of heat energy input to the cooling ferromagnet, but increases friction losses, therefore, it is necessary to reduce the angular velocity of rotation of axis 4 and use a reduction gear 16 to increase the rotation speed of the alternator shaft. The decrease in the rotation speed of the axis 4 helps to improve the conditions of heat transfer to the ferromagnetic rings (or disks), which allows to increase the number of strong permanent magnets 2 for each ferromagnetic ring (or disk) to increase the power of the device.

Consider the action of the claimed device.

The operation of a thermomagnetic motor based on a ferromagnetic ring 1 and a strong permanent magnet 2 is based on the well-known principle of the operation of an electromagnetic motor using force interaction between a magnetized rotor and a stator, in which the stator magnetic field rotates, entraining the rotor, which rotates together with the rotating stator magnetic field . So work, for example, synchronous and asynchronous AC motors. In the claimed technical solution, the stator magnetic field is motionless, being formed by a motionlessly located strong permanent magnet. However, by virtue of the principle of equivalence, the magnetization distribution in the ferromagnetic ring, which rotates in the opposite direction relative to the physical rotation of the ferromagnetic ring as a rotor, also leads to force interaction due to the lag of the magnetization center of the ferromagnetic ring inside the magnetic gap of the strong permanent magnet from its center of magnetic attraction. As a result of this force interaction, the ferromagnetic ring rotates under the action of a pulling force, which tends to combine the indicated centers of magnetization and magnetic attraction. Thus, it remains to ensure the indicated lag of the center of magnetization of that part of the ferromagnetic ring, which is in the gap of a strong permanent magnet, from the center of magnetic attraction of the latter. In this case, it is understood that the rotation of the indicated distribution of magnetization on the ferromagnetic ring in the coordinate system associated with the ferromagnetic ring is inverse to the rotation of the ferromagnetic ring, which leads to a permanent picture of the distribution of magnetization inside the magnetic gap in the coordinate system associated with a fixed strong permanent magnet , and the retraction force is permanent. This problem is solved by using the magnetic viscosity property of the ferromagnet from which the ferromagnetic ring is made in the dynamics of the rotation of the latter under the action of applying a sufficient momentum to the ferromagnetic ring of the starting moment, after which the ferromagnetic ring will maintain the rotation mode provided that the friction moment and the connected load are not more than the rotational moment arising from the indicated force interaction, and the compensation of energy losses during this rotation is a ferromagnet th ring is performed due to the inflow of the ambient heat energy to the ferromagnetic ring, which is cooled by leaving the demagnetization of the magnetic gap portion of the ferromagnetic ring of the known magnetocaloric effect.

One of the important properties of ferromagnetic materials with respect to the technical solution under consideration is their so-called magnetic viscosity, the magnetic aftereffect is the time lag of the magnetization of the ferromagnet from the change in the magnetic field strength. In the simplest cases, the change in the magnetization ΔJ as a function of time t is described by the formula

where J ₀ and J _∞ are, respectively, the magnetization values immediately after the magnetic field strength H changes at the moment t = 0 and after the establishment of a new equilibrium state, τ is a constant characterizing the rate of the process and is called the relaxation time constant. The value of τ depends on the nature of magnetic viscosity and in various materials can vary from 10 ^-9 s to several tens of hours.

There are two types of magnetic viscosity: diffusion (Richter) and thermofluctuation (Jordan). In the first of them, the magnetic viscosity is determined by the diffusion of impurity atoms or defects in the crystal structure. An explanation of the role of impurities was given, J. Snock, and a more rigorous theory was constructed, L. Neel, and is based on the assumption of the predominant diffusion of impurity atoms into those interatomic gaps of the crystal that are oriented in a certain way relative to the direction of spontaneous magnetization. This creates a local induced anisotropy, leading to stabilization of the domain structure. Therefore, after changing the magnetic field, a new domain structure is not established immediately, but after the diffuse redistribution of the impurity, which is the reason for the magnetic viscosity.

The second type of magnetic viscosity is more universal and is observed in almost all ferromagnets, especially in the field of magnetic fields comparable with the coercive force. Néel proposed a thermofluctuation mechanism to explain this type of magnetic viscosity. Thermal fluctuations contribute to overcoming by the domain walls of energy barriers in magnetic fields lower than the critical field. In highly coercive alloys consisting of single-domain regions, a particularly high magnetic viscosity is observed, since in this case thermal fluctuations provide additional energy for the irreversible rotation of the spontaneous magnetization of those particles whose potential energy in the external magnetic field is insufficient for their magnetization reversal.

In addition to these basic mechanisms of magnetic viscosity, there are others. For example, in some ferrites, the contribution of magnetic viscosity comes from the redistribution of electron density (electron diffusion between ions of different valencies). Such phenomena in ferromagnets as loss of magnetization reversal, a temporary decrease in the relative magnetic susceptibility χ, and its frequency dependence [8-10] are closely related to magnetic viscosity.

The claimed technical solution, as already indicated, is based on the use of the dynamic interaction of a ferromagnetic substance with a magnetic field created by a strong permanent magnet. A ferromagnetic substance is characterized by a rather complex dependence of its magnetic susceptibility χ on the magnitude of the magnetic field acting on it by the intensity H according to the well-known Stoletov curve. In the absence of a magnetic field, a ferromagnetic substance has an initial magnetic susceptibility χ _NACH , and as the magnetic field increases, the magnetic susceptibility first increases, reaches its maximum value χ _MAX at a magnetic field strength H *, and then decreases again, and in the saturation region of magnetic induction (in a para process) its product with the magnitude of the magnetic field remains almost unchanged, determining the saturation magnetization J _HAC (∞) = µ _О χ (Н) H _HAC ≈const (Н) in the range of us saturating magnetic fields Н _О ≤H _HAC ≤H _MAX , realized in the second (working) part of the magnetic gap, as shown in Fig. 2; wherein µ _O = 1.256. 10 ^-6 GN / m is a constant called the absolute magnetic permeability of a vacuum. The indicated saturation magnetization value is established exponentially in time; therefore, the value of J _HAC (∞) takes place in the steady state, theoretically as t → ∞, and for practically a certain number m of relaxation constants τ, taking into account relation (1), when ΔJ (mτ) → 0.

The operation of the device shown in Fig. 1 consists in preliminary increasing the magnetic susceptibility of the ferromagnetic ring 1 to its maximum value χ _MAX, for which the first part of the magnetic gap with a uniform magnetic field strength equal to H * is used in it, as can be seen from Fig. 2 after which the process of magnetic retraction of ferro-matter into the second (working) part of the magnetic gap of the strong permanent magnet 2 is carried out, magnetization to saturation of the ferromagnet, and upon its exit from the magnetic gap, its magnitude demagnetization magnetic susceptibility lowered to the initial value χ _HACH with cooling, after which the ferromagnetic substance (outside the magnetic field) again heated by thermal energy from the environment in the mechanism of heat conduction, and a cycle of action is repeated again and again, causing continuous rotation of the ferromagnetic ring.

With a sufficient degree of accuracy, the well-known Stoletov curve (Fig. 3) can analytically be given by a continuous function of the form χ (Н):

so that for H = 0 we have χ (0) = χ _NACH, for H = H * we have χ (H *) = χ _MAX ; and as H → ∞ we have χ (∞) → 0, which corresponds to the Stoletov concept.

Figure 3 shows a graph for the values of the magnetic susceptibility of a ferromagnet at various coordinates x of the magnetic gap in the range - L≤x≤L with a stationary ferromagnetic ring (ω = 0), i.e., in steady state. It is seen that in the first half of the magnetic gap (Fig. 2), the maximum magnetic susceptibility χ _{MAX is established,} and in the second, the minimum χ _MIN , at which the magnetization is saturating L _HAС (∞), as can be seen in Fig. 5. The transitions from χ _HAACH to χ _MAX and further to χ _MIN and again to χ _HAACH , although sharp, but not spasmodic, which is determined by the influence of edge effects at the boundaries of the magnetic field transitions in the magnetic gap.

In the first part of the magnetic gap of length L, when the ferromagnetic substance is pulled along the x axis at a speed of V = ω * R during the time Δt = L / ω * R, the magnetic susceptibility of the ferromagnet will exponentially increase to the maximum possible value χ _MAX * at this drawing speed, as seen from Fig. 3. As will be shown below, the angular velocity of rotation of the ferromagnetic ring ω *, corresponding to the maximum rotational moment in the ring, is ω * = L / ΔtR = L / λτR. Therefore, the quantity χ _MAX (Н *) depends on the value of the angular velocity of rotation of the ferromagnetic ring and for ω = 0, that is, when the ferromagnetic ring is stationary, χ _MAX (Н *) | _{ω = 0} = χ _MAX >> χ _{MAX *,} although the excess of χ _MAX * relative to the value of χ _{MAX is} insignificant - only about 6.6%.

The magnitude of the magnetization of the ferromagnet at the end of the first half of the magnetic gap J _HAX * reaches

as seen in Fig. 5.

Since in the second part of the magnetic gap of the strong permanent magnet 2 there is an inhomogeneous magnetic field linearly increasing along the x coordinate, which has an analytical form:

where 0≤x≤L, L is the length of the second part of the magnetic gap, then the magnetization J (x) of the ferromagnetic substance located in the second part of the magnetic gap is calculated based on the recurrence relations. For this purpose we divide the interval L in n small and identical segments, the dimensionless value of the ratio x / L = ε denote a discrete representation of integer index i, and the ratio (H _MAX -H _O) / N _O is denoted, as before, by setting the magnetic gradient field p, then expression (4) is written in index form as

and for i = n we have H _n = H _MAX .

Since the state of the ferromagnet at the beginning of its interaction with the magnetic field of the second part of the magnetic gap has already formed, and the magnetic susceptibility is brought to the maximum value χ _MAX * in the magnetic field H *, and the magnetic field at the beginning of this part of the magnetic gap jumps up to the value of H _O >> H *, then when analyzing the magnetization of a ferromagnet inside the magnetic gap of the working permanent magnet, only its falling part of the Stoletov curve in the index representation should be taken into account in expression (2):

which corresponds to Fig. 5, and for i = n we have χ _n = χ _MIN *> χ _MIN, and the indicated excess of χ _MIN * over χ _{MIN is} insignificant (about 6.6%).

When analyzing the magnetization dynamics of a ferromagnet defined by the general expression J = μ _O χ H, it should be borne in mind that a temporary change in this quantity depends only on a temporary change in magnetic susceptibility, which has the property of magnetic viscosity, that is, cannot change abruptly, as in this device the magnetic field strength at the boundary of the first and second parts of the magnetic gap changes practically abruptly, from H * to H _O. This explains the presence of a magnetization spike with a short front of the order of Δt * = - τln [1- (H * / H _O )], as can be seen in Fig. 5, tending to the value J _MAX = μ _O χ _MAX * Н _O , but not reaching it due to the simultaneous action of a saturating magnetic field, which decreases the value of magnetic susceptibility in time, after which the magnetization for the steady state decreases exponentially to a value of saturation magnetization equal to J _HAC (∞), and in this case to J _HAC (∞) + ΔJ *, which exceeds the saturation magnetization for steady state the value ΔJ *.

Since the magnetization of the differential volume of the ferromagnetic ring is dv = Sdx (S is the cross section of the ferromagnetic ring inside the magnetic gap) located at any x coordinate in the interval 0≤x≤L at any time, it is defined as J (x) = µ _O χ [H (x)] H (x), where H (x) is given by expression (4), then, given (1), we note that to find it, it is necessary to find its previous value at the coordinate (x-dx) or, that the same with a sufficiently large number of partitions of the segment L into n equal parts, for finding the magnetization in the i-th interval , we must first find it on the (i-1) interval, then we have:

But to find the value of J _(i-1) , you must first find the value of J _(i-2) , etc. to J ₁ , the value of which is determined simply:

используются установившиеся значения этих величин, а не мгновенные значения в текущем времени.Note that in parentheses of expressions (6) and (7), as well as subsequent similar expressions for differences

the steady-state values of these quantities are used, not the instantaneous values in the current time.

Then we come to a system of recurrence equations of the form:

Based on (8), the general expression for the magnetization in the k-th interval of the interval 0≤x≤L (or, what is the same, 0≤ε≤1 - for the dimensionless designation of the variable) can be written in the form:

In expression (9), the well-known factor μ _О χ _MAX * Н * is a constant value, therefore, the dimensionless function that is in braces and equal to is of interest:

To calculate the distribution of this function in the interval i = 1, 2, 3 ,. ... n using the Mathcad computer program, it is necessary to represent this function in integral form, that is, using continuous functions of the parameter ε = x / L. Then we get:

where λ = Δt / τ, and p = (H _MAX -H _O) / H _O, and the variable ranges 0≤ε≤1.

, функция максимальна при λ=1,23 независимо от текущего значения переменной ε, откуда находим оптимальное значение угловой скорости ω* вращения ферромагнитного кольца, при которой достигается максимум вращательного момента:As the analysis of the function f (ε) by extremum shows by equating to zero its derivative with respect to the parameter λ, i.e.

, the function is maximum at λ = 1.23 regardless of the current value of the variable ε, whence we find the optimal value of the angular velocity ω * of rotation of the ferromagnetic ring at which the maximum torque is reached:

We turn to the question of how the centers of magnetic attraction X _H and magnetization X _J are spaced apart from each other along the x axis in the direction of drawing the ferromagnetic substance in the magnetic gap. To determine the center of magnetic attraction inside the second part of the magnetic gap using the Mathcad program, using the root operator, we write the equation, from the solution of which the value of the relative center of magnetic attraction α is found:

Figure 6 shows a graph of the relative position of the center of magnetic attraction α as a function of the parameter p, as well as a table of some values of α (p). It is seen that the position of the center of magnetic attraction X _H = (0.5 ... 0.707) L. So, for the most suitable values of p = 5 ... 10, we have X _H = (0.66 ... 0.68) L, that is, significantly farther from the middle of the second part of the magnetic gap at x = L / 2.

To find the magnetization center of the ferromagnet X _J located inside the second part of the magnetic gap of length L, we use the modified expression (11) for the relative distribution of the magnetizations of the ferromagnet f (ε) under certain specific conditions: p = 10, τ = 5 · 10 ^-4 sec , λ = 1.23, and the introduced value σ = J _HAC (∞) / J _HACH * = 2 ... 4 and specifically σ = 2.

The modified equation can be written in the form:

where Δt * = - τln [1- (Н * / Н _O )] = - 5 · 10 ^-4 ln0.9 = 5.27 * 10 ^-5 s, Δt = 1.23 * 5 · 10 ^-4 = 6 , 15 · 10 ^-4 s. The ratio Δt / Δt * = 11.67. In this case, equation (14) for given values takes the form:

which at ε = 0 is equal to unity, and at ε = 1 it takes the value σ = 2, which corresponds to the conditions of the problem.

Fig. 7 shows a graph for the considered example. It can be seen that the maximum of the relative magnetization function of the ferromagnet is pressed to the beginning of the second part of the magnetic gap; therefore, the magnetization center X _{J is} clearly shifted to the beginning of this part of the gap relative to its center x = L / 2. The exact value of this center is calculated by the formula

by solving by which, by successive approximations, we find the value of ε *, which determines the position of the center of magnetization X _J = ε * L. Solution (16) taking into account (15) at the angular velocity ω * of rotation of the ferromagnetic disk has the form ε * = 0.445, so that the center of magnetization is at the coordinate X _J = 0.445L.

Comparing the average values of the positions of the centers of magnetic attraction and magnetization, we see that they are separated by the interval ΔX = X _H -X _J = (0.67-0.45) L = 0.22L, therefore, the pulling force F (ω * ) a ferromagnet in the magnetic gap, and the ferromagnetic disk receives a torque M _BP * = F (ω *) R under the action of this force.

It is known that the differential force dF (ω) acting on the side of an inhomogeneous magnetic field with a gradient of tension along the x axis equal to grad Н _X on the differential ferromagnetic volume dv with magnetic moment J (x) dv is

since dv = Sdx, x / L = ε, dx = Ldε and grad H _X = H _O (p-1) / L.

Note that the approximate equal sign is taken due to the fact that the magnetization ejection at the beginning of the second part of the magnetic gap does not actually reach µ _O χ _MAX * Н _O , as was indicated earlier. So, from Fig. 7 it is seen that the maximum of the function f (ε) is 0.86 of the expected value, which should be taken into account in accurate estimates of the device’s energy. For the considered example of the device implementation, the exact expression for (17) corresponds to dF (ω, ε) = 0.86 μ _O χ _MAX * Н _O ² f (ε) (p-1) Sdε. In expression (17), the factor μ _O χ _MAX * Н _O ² (p-1) S = const (ε), and the variable part of this expression is df (ε) = f (ε) dε, where the differential of the relative strength function is determined from ( eleven). The distribution of forces for differential volumes dv located on the x coordinates or dimensionless coordinates ε (which is the same) is found from the equation:

and these force differentials for the corresponding differential volumes of the ferromagnetic ring inside the second part of the magnetic gap are measured in Newtons [N].

The maximum value of the retraction force of the ferromagnet by the second part of the magnetic gap F (ω *) is determined by the difference of the integrals:

where α = X _H / L is the relative position of the center of magnetic attraction of the second part of the magnetic gap.

Substituting the value of the function from (11) into the integrands (19), we obtain an explicit expression for the maximum retraction force F (ω *), the distribution of which in the angular velocity function ω is shown in the graphs of Fig. 8 for two different values of Н _О.

You can write the following expressions for (10) with the following parameters:

α = 0.67, λ = 1.23, p = 2

and then, substituting these expressions in (19), we obtain the maximum of the retracting force F (ω *) at the optimal rotation speed of the ferromagnetic ring ω * equal to

For the considered example (20), it has the solution F (ω *) = 0.106 µ _О χ _MAX * Н _О ² (p-1) S.

It can be shown that at other angular velocities ω> ω * and ω <ω *, the forces F (ω) <F (ω *).

Consider an example.

Let χ _MAX * = 1000, Н _O = 10 ⁴ A / m, p = 9 and S = 6 * 10 ^-5 m ² (with a ferromagnetic ring 3 mm thick and 2 cm wide), then F (ω *) = 0.106 * 1.256 · 10 ^-6 * 10 ³ * 10 ⁸ * 9 * 6 · 10 ^-5 = 7.19 N. If the average radius of the ferromagnetic ring is R = 0.1 m, then the rotational moment is M _BP = F (ω *) R = 0.719 Nm If L = 0.02 m and τ = 5 · 10 ^-4 , then the optimal angular velocity of rotation of the ferromagnetic ring is ω * = L / 1.23 R τ = 400 rad / s = 63.7 r / s. The maximum power on the shaft P _MAX = M _BP ω * = 287.6 watts. The device must consume thermal power from the environment, for example, from the water of the corresponding water basin. By varying the parameters L and R, it is possible to obtain other angular rotational speeds of the ferromagnetic ring in order to ensure the rotation speed of the generator shaft 7 (Fig. 1) equal to 50 r / s. This will generate an alternating current with a standard network frequency of 50 Hz.

It is known from the theory of automatic control that the attached load and friction reduce the speed of the axis of rotation 4, and a steady state of the regime of its rotation is achieved at the point of intersection of the curve of the force characteristic F (ω) with the load direct feedback when the derivatives of these characteristics have opposite signs. The load moment is determined by the slope of the feedback loop and the derivative of the load line is positive, therefore, a steady state in the automatic control system is achieved on the descending branch of the power characteristic F (ω), as can be seen from Fig. 8. Therefore, the actually removed power on the axis of rotation 4 is always less than the maximum P _MAX and the speed of the steady-state rotation process will always be higher than ω *. For the considered example, at maximum load M _{H MAX, the} power on the axis of rotation can reach values of the order of 200 W with an appropriate selection of sizes L and R at an axis rotation speed of about 50 r / s with the parameter τ taken into account. In this case, such a heat flux power should come to the ferromagnetic ring from the external environment. This means that if the water temperature drops during heating of the ferromagnet at 1 ° C, the required water flow will be approximately 50 g / s or 180 l / h.

To increase the intensity of heat transfer, it is advisable to immerse the ferromagnetic ring in its heating liquid, for example, purified water or another liquid with its circulation in a closed cycle with a heating radiator and a pump to ensure circulation (in this case, the radiator can be immersed in running water). To reduce friction losses, nitrobenzene having a low viscosity compared to water can be chosen as a circulating fluid. In addition, it is necessary to significantly reduce the angular velocity of rotation of the ferromagnetic ring, which will require the use of a reduction gear 16 between the axis of rotation 4 and the electric generator 7, as can be seen in Fig. 10. At the same time, several ferromagnetic rings can be connected to a single axis of rotation 4, and each of them can be connected with several equidistant strong permanent magnets 2 with the sequential inclusion of all their magnetization windings to the output of the magnetization control unit 10 (Fig. 1), which is repeatedly increase net power.

As can be seen in Fig. 9, the power on the axis of rotation increases with increasing angular velocity of rotation of axis 4, exponentially approaching the corresponding threshold levels. This means that a decrease in the angular velocity of rotation of ferromagnetic rings associated with a single axis of rotation (Fig. 10) reduces the power received from each ferromagnetic ring; therefore, this decrease is compensated by an increase in the number of ferromagnetic rings and the associated strong permanent magnets.

Consider the process of automatic control of an electric generator 7 according to the scheme of Fig. 1. The purpose of this control is to maintain the frequency of generated oscillations within small permissible limits, for example, a frequency of 50 Hz with tolerances of ± 0.5 Hz (no worse than 1%), while varying the load value (power consumed from the generator). To accomplish this task, automatic control of the bias current in coils of strong permanent magnets leads to a corresponding change in the magnetic field strength Н _О in the magnetic gap, the value of which is included in expression (20) with a factor. The effectiveness of this control is due to the fact that the value of H _O in this expression is squared. For example, to increase the power by a factor of four, the bias current is only doubled or even less, given the intrinsic magnetization of a strong permanent magnet (without the bias current). Fig. 8 shows graphs for the highest load of the electric generator (M _{H MAX} ) and the smallest (M _{H MIN} ). The magnetizing currents are selected so that, regardless of the load on the generator, the rotation speed of its shaft is kept constant (for example, 50 r / s) with acceptable accuracy. From Fig. 8, it is seen that at maximum load the oscillation frequency of the alternating current is slightly lower, and at minimum load it is slightly higher than the average frequency value. The same can be seen from the graphs in Fig. 9.

The automatic control circuit includes a reference voltage generator 11, for example, with a frequency of 50 Hz, the output signal of which is compared with the frequency of the signal from the output of the tachogenerator 6 in a phase-sensitive rectifier 8, the output signal of which is filtered either by a low-pass filter 9 (in the static control circuit with residual errors), or by an integrator, instead of a low-pass filter, (in this case, the regulation scheme is astatic with zero residual error, but with reduced speed). An error signal with the corresponding sign and magnitude is fed to the magnetization control unit 10, changing the magnetization current in strong permanent magnets 2. A three-phase rectifier 12 (according to the Larionov circuit) with a ripple smoothing filter at a frequency of 300 Hz is used to power the magnetization control unit. In addition, the three-phase output of the generator 7 is associated with an electrical load with fixed limits of its possible change.

You should specifically focus on the magnetocaloric effect, due to which the operation of the device.

Suppose that in the initial state an unmagnetized ferromagnet has a temperature T _O and a specific heat capacity c _O For the mass of a ferromagnet m in question, we have its internal thermal energy Q _O = c _O mT _O. If the density of the ferromagnet is ρ, then the volume of the indicated mass m is equal to v = m / ρ. If said volume placed in the magnetic gap of a permanent magnet which generates a magnetic field of intensity H, the magnetic energy stored in this volume, as is known, is equal to W = μ _O μvN ^2/2 where μ = χ + 1 - relative magnetic permeability ferromagnet. In this case, its magnetization occurs, and the law of conservation of energy is expressed by the relation

where c _H is the specific heat of a magnetized ferromagnet (with _H <c _O ), T ₁ is the temperature of its volume v during quasi-adiabatic magnetization, and T ₁ > T _O (during magnetization, as is known, a ferromagnet heats up), η is the coefficient of magnetocaloric activity depending on the properties of the ferromagnet. After the volume v of the ferromagnet leaves the indicated magnetic gap during its quasi-adiabatic demagnetization, this volume is cooled, and the energy conservation law is written as for adiabatic demagnetization

where T ₂ is the temperature of the considered volume of the ferromagnet during its adiabatic demagnetization (strictly speaking, quasi-adiabatic demagnetization takes place).

, то есть внутренняя тепловая энергия данного объема ферромагнетика, который сначала намагничивается в магнитном зазоре, а затем покидает его, размагничиваясь в адиабатическом процессе (за счет вращения ферромагнитного кольца), уменьшается на величинуWe show that T ₂ <T _O

, i.e., the internal thermal energy of a given volume of a ferromagnet, which is first magnetized in the magnetic gap, and then leaves it, demagnetized in the adiabatic process (due to the rotation of the ferromagnetic ring), decreases by

According to (21), for the value c _{H, we can} write the expression

Substituting (24) into (22), we obtain

It follows from (25) that

Since ηW / c _O m = µ _O ηµvH ² / 2c _O m = µ _O ηµH ² / 2ρc _O > 0, we really have the inequality T _O -T ₂ > 0, that is, T _O > T ₂ , and the final temperature T _{2 of} the volume of the ferromagnet under consideration is below its initial temperature T _O (before entering the magnetic gap with the magnetic field H).

The change in the internal thermal energy of the considered volume of a ferromagnet in the processes of its quasi-adiabatic magnetization and demagnetization was determined in (23).

It should be specially noted that the magnetocaloric effect is most often used for deep cooling of superconductors in cryogenic technology. However, this does not mean that this effect is manifested only at infra-low temperatures and in conditions of adiabaticity, that is, isolation from the external environment. The magnetocaloric effect directly follows from the first-order phase transition, in which the specific heat of the ferromagnet abruptly decreases when a certain boundary value of the saturating magnetic field is reached, and this decrease (with subsequent restoration upon demagnetization) does not require any isolation of the ferromagnet from the environment or or infra-low temperature.

The considered volume of the ferromagnet is v = LS, where L is the length of the magnetic gap of the permanent magnet, S is the cross section of the ferromagnetic ring covered by the magnetic gap with the magnetic field, the magnetic gap passes in time Δt = L / ωR, where ω is the angular velocity of rotation of the magnetic ring of radius R therefore, the heat loss power is calculated according to the expression:

So, from (27) it is seen that the loss of mechanical energy of a rotating ferromagnetic ring is compensated in the heat transfer mechanism by the thermal energy of the external environment. In this case, the process of changing the internal energy of the ferromagnetic ring is not adiabatic in its strict interpretation, and any differential volume of the ferromagnetic ring upon its exit from the magnetic gap restores its specific heat capacity, receiving thermal energy from the external medium for a time ΔТ = (1 / n) - 2Δt = 2 (πR-L) ωR. In the above example, the ferromagnetic ring heats up in the magnetic field gap for a time of 2Δt = 1.23 ms, and then quickly cools during demagnetization and at the same time heats up with the external environment for 18.77 ms (when using one strong permanent magnet).

Without thermal contact with the external environment, the claimed device will not work. This is in full agreement with the law of conservation and conversion of energy. In addition, to start the rotational motion, it is necessary to provide two indispensable conditions: firstly, unscrew the ferromagnetic ring by external action to the required angular velocity ω> ω *, and secondly, provide the friction moment and the connected load on the axis of rotation not exceeding the moment rotation M _BP . It should be noted that, if the moment of friction and the attached load is less than the rotational moment, then the ferromagnetic ring with the idle automatic control system will increase its angular velocity of rotation until these moments are equalized.

The claimed technical solution generates mechanical energy from the thermal energy of the external environment, for example, water, implementing a fundamentally new mechanism of energy conversion.

The strong permanent magnet used in the system under consideration is made of magnetically rigid ferromaterials (ferrites), for example, SmCo ₃ , NdFeB, or AlNiCo, which have high residual magnetization induction [10-11].

In conclusion, it should be noted that in order to increase the efficiency of the proposed method in terms of its energy, ferromagnetic materials should be developed that have the required magnetic viscosity parameters, a relatively low saturation induction at the highest magnetic susceptibility, and, most importantly, with a significant magnitude of magnetocaloric activity to satisfy the expression ( twenty).

Literature

1. Smaller OF, Magnetoviscous pendulum. RF patent No. 2291546, publ. No. 01 dated January 10, 2007.

2. Smaller OF, Ferromagnetically viscous rotator. RF patent No. 2309527, publ. No. 30 dated October 27, 2007.

3. Smaller OF, Magnetic motor. RF patent No. 2310265, publ. No. 31 dated November 10, 2007.

4. Smaller OF, Magnetoviscous rotator. RF patent №2325754, publ. No. 15 dated 05/27/2008.

5. Smaller OF, Method for producing energy and a device for its implementation. RF patent No. 2332778, publ. No. 24 dated 08/17/2008.

6. Smaller OF, Ferromagnetically viscous engine. RF patent No. 2359398, publ. No. 17 dated 06/20/2009.

7. Smaller OF, Device for stabilizing the frequency of the generator. RF patent No. 2368073, publ. No. 26 dated 09/20/2009.

8. Kronmuller H., Nachwirkung in Ferromsgnetika, 1968.

9. Vonsovsky S.V., Magnetism, M., 1971.

10. Mishin D.D., Magnetic materials, M., 1981.

11. Wolfart E., Magnetic-solid materials, trans. from English., M.-L., 1963.

Patent Search Data

SU 1001487 A, 02.28 / 1983. SU 243977 A, 05/14/1969.

SU 219667 A, 06/14/1968. SU 107575 A, 31/12/1957.

Claims (1)

An automatic generator control device containing a ferromagnetic ring mechanically connected to the axis of rotation through the yokes, part of the ferromagnetic ring is placed in the saturating magnetic field of a strong permanent magnet equipped with a magnetizing coil, and the other part is connected to a heat-generating medium, for example, purified water taken from the corresponding water pool, with the axis of rotation is mechanically connected a three-phase alternator connected to a three-phase rectifier and to electricity load, the output of the three-phase rectifier through the magnetization control unit is connected to the magnetization coil of a strong permanent magnet, the input of the magnetization control unit is connected to the output of a series-connected reference voltage generator, a phase-sensitive rectifier and a low-pass filter (or integrator), characterized in that with the axis of rotation of the ferromagnetic the ring is mechanically connected by a tachogenerator, the output of which is connected to the second input of the phase-sensitive rectifier, and the magnetic gap nth permanent magnet is made of two parts, the first of which forms a uniform magnetic field with a strength that ensures that the magnetic susceptibility of the ferromagnet is maximized along the length L of this part of the magnetic gap, and the second part of the magnetic gap of length L forms a saturating magnetic field at the beginning of this part of the magnetic of the gap and further in the direction of movement of the ferromagnetic ring, the magnetic field increases linearly in strength to the end of the magnetic gap, and the angular velocity ω * of rotation of a ferromagnetic ring, corresponding to the maximum of the rotational moment arising in it, is determined by the condition ω * = L / λRτ, where λ = 1.23 and R is the average radius of the ferromagnetic ring, τ is the relaxation time constant of the magnetic viscosity of the ferromagnet from which the ferromagnetic ring is made.

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